PT J
AU HANDFORD, PA
   MAYHEW, M
   BARON, M
   WINSHIP, PR
   CAMPBELL, ID
   BROWNLEE, GG
AF HANDFORD, PA
   MAYHEW, M
   BARON, M
   WINSHIP, PR
   CAMPBELL, ID
   BROWNLEE, GG
TI KEY RESIDUES INVOLVED IN CALCIUM-BINDING MOTIFS IN EGF-LIKE DOMAINS
SO NATURE
LA English
DT Article
ID beta-hydroxyaspartic acid; epidermal growth-factor; human factor-ix; nucleotide-sequence; protein; gene; homology; repeats; site
AB MANY extracellular proteins with diverse functions contain domains similar to epidermal growth factor (EGF), a number of which have a consensus Asp/Asn, Asp/Asn, Asp*/Asn*, Tyr/Phe (where the asterisk denotes a beta-hydroxylated residue) 1.  These include the coagulation factors IX and X, proteins with two EGF-like domains, the first of which contains the consensus residues 2.  The first EGF-like domain of human factor IX contains a calcium-binding site, which is believed to be responsible for one of the high-affinity sites detected in this protein 3.  Similar results have been obtained for bovine factor X 4.  We have now used protein engineering and H-1-NMR techniques to investigate the importance of individual consensus residues for ligand binding.  Measurement of a calcium-dependent Tyr 69 shift 3 in the isolated first EGF-like domain from human factor IX demonstrates that Asp 47, Asp 49, and Asp 64 are directly involved in this binding.  Gln 50, whose importance has previously been overlooked, is also involved in this binding.  Two mutations 5 in this domain, Asp 47 --> Glu, and Asp 64 --> Asn, present in patients with haemophilia B, reduce calcium binding to the domain > 4-fold and > 1,000-fold, respectively.  Furthermore, the defective calcium binding of Asn 64 can be partially rescued by the compensatory mutation Gln 50 --> Glu.  This latter mutation, when introduced singly more than doubles the affinity of the domain for calcium.  This study thus defines residues involved in a new type of calcium-binding site and provides strong circumstantial evidence for calcium-binding motifs in many extracellular proteins, including the developmentally important proteins of Drosophila, notch, delta and crumbs 1,6-8.
C1 UNIV OXFORD,DEPT BIOCHEM,OXFORD OX1 3RE,ENGLAND.
   UNIV OXFORD,OXFORD CTR MOLEC SCI,OXFORD OX1 3RE,ENGLAND.
C3 University of Oxford; University of Oxford
RP HANDFORD, PA (corresponding author), UNIV OXFORD,SIR WILLIAM DUNN SCH PATHOL,S PARKS RD,OXFORD OX1 3RE,ENGLAND.
NR 22
TC 281
Z9 302
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 164
EP 167
DI 10.1038/351164a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500057
PM 2030732
DA 2026-03-10
ER

PT J
AU GOODNOW, CC
   BRINK, R
   ADAMS, E
AF GOODNOW, CC
   BRINK, R
   ADAMS, E
TI BREAKDOWN OF SELF-TOLERANCE IN ANERGIC LYMPHOCYTES-B
SO NATURE
LA English
DT Article
ID systemic lupus-erythematosus; t-cell tolerance; major histocompatibility complex; transgenic mice; clonal anergy; receptor; inactivation; expression; induction; deletion
AB PRODUCTION of autoantibodies, which characterizes most autoimmune diseases, is normally avoided by active elimination 1-7 or functional inactivation (anergy) 8-15 of B and T lymphocytes bearing receptors for self antigens. The mechanisms leading to the escape of self-reactive clones from these normal tolerance mechanisms in autoimmune diseases nevertheless remain obscure. Here, we demonstrate that clonal anergy in B lymphocytes is a reversible process, and that silenced self-reactive B cells can be reactivated under particular conditions to give rise to vigorous antibody responses. Reactivation of anergic lymphocytes may explain many examples of transient autoimmune reactions in normal individuals, and may under pathological conditions be important in the development of chronic autoimmune disease.
C1 STANFORD UNIV, HOWARD HUGHES MED INST, STANFORD, CA 94305 USA.
   STANFORD UNIV, DEPT MICROBIOL & IMMUNOL, STANFORD, CA 94305 USA.
C3 Stanford University; Howard Hughes Medical Institute; Stanford University
RP GOODNOW, CC (corresponding author), UNIV SYDNEY, CENTENARY INST CANC MED & CELL BIOL, SYDNEY, NSW 2006, AUSTRALIA.
NR 24
TC 229
Z9 258
U1 0
U2 4
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 532
EP 536
DI 10.1038/352532a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600064
PM 1830923
DA 2026-03-10
ER

PT J
AU KAWAMURA, S
   MURAKAMI, M
AF KAWAMURA, S
   MURAKAMI, M
TI CALCIUM-DEPENDENT REGULATION OF CYCLIC-GMP PHOSPHODIESTERASE BY A PROTEIN FROM FROG RETINAL RODS
SO NATURE
LA English
DT Article
ID outer segment; photoreceptor-membranes; cgmp phosphodiesterase; guanylate-cyclase; plasma-membrane; salamander rods; binding protein; activation; conductance; sequence
AB IN vertebrate photoreceptors, light reduces cyclic GMP concentration and closes cGMP-activated channels to induce a hyperpolarizing response 1. As Ca2+ can permeate the channels and the Na+ - CA2+ exchanger continuously extrudes Ca2+, closure of the channel results in a reduction of the inter-rod Ca2+ concentration 2-4.  This is believed to be one of the mechanisms of light adaptation produced by activation of guanylate cyclase 5-9.  Effects of Ca2+ on the cGMP phosphodiesterase (PDE) have been reported 10-15, but their physiological significance has remained unclear.  We have perfused the inside-out preparation of a frog rod outer segment (I/O ROS (ref. 16), originally termed truncated ROS (ref. 17)), and find that Ca2+ in a physiological range regulates the light-activation of PDE.  Therefore, PDE regulation by Ca2+ must be involved in light-adaptation in rods.  The effect is mediated by a newly found protein which binds to disk membranes at high Ca2+ concentrations and prolongs PDE activation.
RP KAWAMURA, S (corresponding author), KEIO UNIV,SCH MED,DEPT PHYSIOL,SHINANOMACHI 35,SHINJUKU KU,TOKYO 160,JAPAN.
NR 22
TC 210
Z9 219
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 420
EP 423
DI 10.1038/349420a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400053
PM 1846944
DA 2026-03-10
ER

PT J
AU MIRANKER, A
   RADFORD, SE
   KARPLUS, M
   DOBSON, CM
AF MIRANKER, A
   RADFORD, SE
   KARPLUS, M
   DOBSON, CM
TI DEMONSTRATION BY NMR OF FOLDING DOMAINS IN LYSOZYME
SO NATURE
LA English
DT Article
ID egg-white lysozyme; molten globule state; alpha-lactalbumin; ribonuclease-a; protein; intermediate; exchange; kinetics
AB ALTHOUGH there has been much speculation on the pathways of protein folding, only recently have experimental data on the topic been available.  The study of proteins under conditions where species intermediate between the fully folded and unfolded states are stable has provided important information, for example about the disulphide intermediates in BPTI 1,2, cis/trans proline isomers of RNase A3 and the molten globule state of alpha-lactalbumin 4.  An alternative approach to investigating folding pathways has involved detection and characterization of transient conformers in refolding studies using stopped-flow methods coupled with NMR measurements of hydrogen exchange 5,6.  The formation of intermediate structures has been detected in the early stages of folding of cytochrome c (ref. 7), RNaseA 8 and barnase 9.  For alpha-lactalbumin, hydrogen exchange kinetics monitored by NMR proved to be crucial for identifying native-like molten globule state 10.  An analogous partially folded protein stable under equilibrium conditions has not been observed for the structurally homologous protein hen egg-white lysozyme, although there is evidence that a similar but transient state is formed during refolding. Here we describe NMR experiments based on competition between hydrogen exchange and the refolding process which not only support the existence of such a transient species for lysozyme, but enable its structural characteristics to be defined.  The results indicate that the two structural domains of lysozyme are distinct folding domains, in that they differ significantly in the extent to which compact, probably native-like, structure is present in the early stages of folding.
C1 UNIV OXFORD,INORGAN CHEM LAB,OXFORD OX1 3QR,ENGLAND.
   HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138.
   UNIV OXFORD,OXFORD CTR MOLEC SCI,OXFORD OX1 3QR,ENGLAND.
C3 University of Oxford; Harvard University; University of Oxford
RP MIRANKER, A (corresponding author), HARVARD UNIV,COMM HIGHER DEGREES BIOPHYS,7 DIVIN ST,CAMBRIDGE,MA 02138, USA.
NR 29
TC 245
Z9 254
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 633
EP 636
DI 10.1038/349633a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000067
PM 2000138
DA 2026-03-10
ER

PT J
AU STEBBINS, JF
AF STEBBINS, JF
TI NMR EVIDENCE FOR 5-COORDINATED SILICON IN A SILICATE GLASS AT ATMOSPHERIC-PRESSURE
SO NATURE
LA English
DT Article
ID molecular-dynamics; si-29 nmr; liquid; coordination; temperature; k2si4o9; sio2
AB KNOWLEDGE of the structure of liquid silicates is essential to understanding the properties of materials ranging from magmas in lava flows to melts in glass processing.  At 1 atmosphere pressure, a wide range of evidence indicates that most silicon cations in these systems are coordinated by four oxygens in a tetrahedral configuration (Si(IV)).  Molecular dynamics computer simulations of these liquids have, however, predicted that defect complexes (of relatively low abundance) consisting of silicon with five oxygen neighbours (Si(V)) are of key importance in the mechanism by which viscous flow takes place 1-5.  I present here direct experimental evidence from Si-29 NMR studies of K2Si4O9 glass that Si(V) does exist in silicate liquids at low pressures, and that the abundance of this species increases with temperature, supporting the idea that Si(V) defects contribute to 'weakening' of the structure of molten silicates.
RP STEBBINS, JF (corresponding author), STANFORD UNIV,DEPT GEOL,STANFORD,CA 94305, USA.
NR 19
TC 191
Z9 200
U1 0
U2 36
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 638
EP 639
DI 10.1038/351638a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200060
DA 2026-03-10
ER

PT J
AU ASHCROFT, AT
   CHEETHAM, AK
   GREEN, MLH
   VERNON, PDF
AF ASHCROFT, AT
   CHEETHAM, AK
   GREEN, MLH
   VERNON, PDF
TI PARTIAL OXIDATION OF METHANE TO SYNTHESIS GAS-USING CARBON-DIOXIDE
SO NATURE
LA English
DT Article
ID nickel-catalysts; decomposition; monoxide; co2
AB INCREASING concern about world dependence on petroleum oil has generated interest in the more efficient use of natural gas 1-4. The conversion of methane to the common feedstock synthesis gas (carbon monoxide and hydrogen) by steam reforming is already well established 5, and we have shown recently that yields of synthesis gas in excess of 90% can be obtained at moderate temperatures and ambient pressure by partial oxidation, with air or oxygen, over supported transition-metal catalysts 6,7. The use of carbon dioxide as an oxidant for conversion of natural gas to synthesis gas is well established in steam reforming 5, and is also known in CO2 reforming (for example, the Calcor process 8,9), in which the use of excess CO2 yields mainly CO. In the present work, we describe an alternative catalytic strategy for CO2 reforming which gives excellent yields (90%) from a stoichiometric (1:1) feed of CO2 and CH4. Carbon deposition ('coking'), which is a hazard of CO2-reforming routes, is suppressed here by the use of catalysts based on platinum-group metals. We show that the exothermic partial oxidation of CH4 and the endothermic CO2- reforming reaction can be carried out simultaneously, thus introducing the possibility of tuning the thermodynamics of the process.
C1 UNIV OXFORD,INORGAN CHEM LAB,OXFORD OX1 3QR,ENGLAND.
C3 University of Oxford
RP ASHCROFT, AT (corresponding author), UNIV OXFORD,CHEM CRYSTALLOG LAB,9 PARKS RD,OXFORD OX1 3PD,ENGLAND.
NR 22
TC 781
Z9 877
U1 7
U2 586
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 225
EP 226
DI 10.1038/352225a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500059
DA 2026-03-10
ER

PT J
AU HUANG, S
   LEE, WH
   LEE, EYHP
AF HUANG, S
   LEE, WH
   LEE, EYHP
TI A CELLULAR PROTEIN THAT COMPETES WITH SV40 T-ANTIGEN FOR BINDING TO THE RETINOBLASTOMA GENE-PRODUCT
SO NATURE
LA English
DT Article
ID susceptibility gene; expression; cells
AB TUMOUR-suppressor genes, such as the human retinoblastoma susceptibility gene (Rb), are widely recognized as being vital in the control of cell growth and tumour formation 1.  This role is indicated, in part, by the suppression of tumorigenicity of human tumour cells after retrovirus-mediated Rb replacement 2-4.  How Rb acts to bring about this suppression is not clear 5 but one clue is that the Rb protein forms complexes with the transforming oncoproteins of several DNA tumour viruses 6-8, and that two regions of Rb essential for such binding frequently contain mutations in tumour cells 9,10.  These observations suggest that endogenous cellular proteins might exist that bind to the same regions of Rb and thereby mediate its function.  We report here the identification of one such human cellular Rb-associated protein of relative molecular mass 46,000 (46K) (RbAP46).  Two lines of evidence support the notion that RbAP46 and simian virus 40 T antigen have homologous Rb-binding properties:  first, several mutated Rb proteins that failed to bind to T also did not associate with RbAP46; and second, both T antigen and T peptide (amino acids 101-118) were able to compete with RbAP46 for binding to Rb.  The apparent targeting of the RbAP46-Rb interaction by oncoproteins of DNA tumour viruses strongly suggests that formation of this complex is functionally important.
RP HUANG, S (corresponding author), UNIV CALIF SAN DIEGO,SCH MED,DEPT PATHOL,LA JOLLA,CA 92093, USA.
NR 18
TC 149
Z9 173
U1 1
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 160
EP 162
DI 10.1038/350160a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500061
PM 2005966
DA 2026-03-10
ER

PT J
AU LINDSTEDT, SL
   HOKANSON, JF
   WELLS, DJ
   SWAIN, SD
   HOPPELER, H
   NAVARRO, V
AF LINDSTEDT, SL
   HOKANSON, JF
   WELLS, DJ
   SWAIN, SD
   HOPPELER, H
   NAVARRO, V
TI RUNNING ENERGETICS IN THE PRONGHORN ANTELOPE
SO NATURE
LA English
DT Article
ID body-mass; mammals; flight; consumption; metabolism; foxes; power; cost
AB THE pronghorn antelope (Antilocapra americana) has an alleged top speed of 100 km h-1, second only to the cheetah (Acionyx jubatus) among land vertebrates 1, a possible response to predation in the exposed habitat of the North American prairie 2. Unlike cheetahs, however, pronghorn antelope are distance runners rather than sprinters, and can run 11 km in 10 min, an average speed of 65 km h-1 (ref. 1). We measured maximum oxygen uptake in pronghorn antelope to distinguish between two potential explanations for this ability:  either they have evolved a uniquely high muscular efficiency (low cost of transport) or they can supply oxygen to the muscles at unusually high levels. Because the cost of transport (energy per unit distance covered per unit body mass) varies as a predictable function of body mass among terrestrial vertebrates, we can calculate the predicted cost to maintain speeds of 65 and 100 km h-1 in an average 32-kg animal 3. The resulting range of predicted values, 3.2-5.1 ml O2 kg-1 s-1, far surpasses the predicted maximum aerobic capacity 4 of a 32-kg mammal (1.5 ml O2 kg-1 s-1). We conclude that their performance is achieved by an extraordinary capacity to consume and process enough oxygen to support a predicted running speed > 20 ms-1 (70 km h-1), attained without unique respiratory-system structures.
C1 UNIV WYOMING,DEPT ZOOL & PHYSIOL,LARAMIE,WY 82071.
   UNIV BERN,DEPT ANAT,CH-3000 BERN 9,SWITZERLAND.
C3 University of Wyoming; University of Bern
NR 27
TC 109
Z9 123
U1 4
U2 107
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 748
EP 750
DI 10.1038/353748a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600066
PM 1944533
DA 2026-03-10
ER

PT J
AU HIGUCHI, H
   GOLDMAN, YE
AF HIGUCHI, H
   GOLDMAN, YE
TI SLIDING DISTANCE BETWEEN ACTIN AND MYOSIN-FILAMENTS PER ATP MOLECULE HYDROLYZED IN SKINNED MUSCLE-FIBERS
SO NATURE
LA English
DT Article
ID frog-muscle; step size; fibers; rabbit; adenosine-5'-triphosphate; generation; movement; force; assay; rigor
AB MUSCLE contraction is generally thought to be driven by tilting 1,2 of the 19-nm-long myosin head 3, part of the thick filament, while attached to actin, part of the thin filament. This motion would produce about 12 nm of filament sliding 4,5.  Recent estimates of the sliding distance per ATP molecule hydrolysed by actomyosin in vitro vary widely from 8 nm (ref. 6) to greater-than-or-equal-to 200 nm (ref. 7). The latter value is incompatible with a power stroke incorporating a single tilting motion of the head. We have measured the isotonic sliding distance per ATP molecule hydrolysed during the interaction between myosin and actin in skinned muscle fibres. We directly estimated the proportion of simultaneously attached actomyosin complexes and their ATP use. We report here that at low loads the interaction distance is at least 40 nm. This distance corresponds to the length of the power stroke plus the filament sliding while actomyosin crossbridges bear negative drag forces 5,8. If the power stroke is 12 nm, then our results indicate the drag distance to be at least 28 nm. Our results could also be explained by multiple power strokes per ATP molecule hydrolysed.
C1 UNIV PENN,DEPT PHYSIOL,PHILADELPHIA,PA 19104.
   UNIV PENN,PENN MUSCLE INST,PHILADELPHIA,PA 19104.
C3 University of Pennsylvania; University of Pennsylvania
NR 20
TC 92
Z9 93
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 352
EP 354
DI 10.1038/352352a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900077
PM 1852212
DA 2026-03-10
ER

PT J
AU GEAR, WK
AF GEAR, WK
TI ARE BL LAC OBJECTS TOO LARGE TO BE GRAVITATIONALLY LENSED
SO NATURE
LA English
DT Article
ID multifrequency observations; millimeter continuum; radio outbursts; blazars; variability; spectra; quasars; 3c-273; models; flux
AB BL LACERTAE objects are extragalactic sources, generally of low redshift, with highly variable, strongly polarized continuum emission ranging from radio wavelengths to X-rays, but with little or no evidence of line emission.  It has been suggested 1 that BL Lacs are in fact more distant radio-loud, optically violently variable (OVV) quasars whose continuum is enhanced, relative to the line emission, by gravitational lensing caused by a star in an intervening galaxy.  I argue here, however, that the spectral similarity of BL Lacs and OVVs over a wide wavelength range can be explained by gravitational lensing only if the continuum-emitting region is small, a requirement that is contradicted by independent observations.
RP GEAR, WK (corresponding author), ROYAL OBSERV,BLACKFORD HILL,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND.
NR 27
TC 15
Z9 15
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 676
EP 678
DI 10.1038/349676a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700039
DA 2026-03-10
ER

PT J
AU ADAMS, SR
   HAROOTUNIAN, AT
   BUECHLER, YJ
   TAYLOR, SS
   TSIEN, RY
AF ADAMS, SR
   HAROOTUNIAN, AT
   BUECHLER, YJ
   TAYLOR, SS
   TSIEN, RY
TI FLUORESCENCE RATIO IMAGING OF CYCLIC-AMP IN SINGLE CELLS
SO NATURE
LA English
DT Article
ID dependent protein-kinase; resonance energy-transfer; catalytic subunit; escherichia-coli; transfer microscopy; skeletal-muscle; expression; compartments; receptor; probes
AB FLUORESCENCE imaging is perhaps the most powerful technique currently available for continuously observing the dynamic intracellular biochemistry of single living cells 1. However, fluorescent indicator dyes have been available only for simple inorganic ions such as Ca2+, H+, Na+, K+, Mg2+ and Cl-. We now report a fluorescent indicator for the adenosine 3',5'-cyclic monophosphate (cAMP) signalling pathway. The sensor consists of cAMP-dependent protein kinase 2 in which the catalytic (C) and regulatory (R) subunits are each labelled with a different fluorescent dye such as fluorescein or rhodamine capable of fluorescence resonance energy transfer in the holoenzyme complex R2C2. When cAMP molecules bind to the R subunits, the C subunits dissociate, thereby eliminating energy transfer. The change in shape of the fluorescence emission spectrum allows cAMP concentrations and the activation of the kinase to be nondestructively visualized in single living cells microinjected with the labelled holoenzyme.
C1 UNIV CALIF SAN DIEGO, HOWARD HUGHES MED INST M-047, LA JOLLA, CA 92093 USA.
   UNIV CALIF SAN DIEGO, DEPT CHEM M-054, LA JOLLA, CA 92093 USA.
C3 University of California System; University of California San Diego; University of California System; University of California San Diego
NR 30
TC 574
Z9 646
U1 0
U2 88
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 694
EP 697
DI 10.1038/349694a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700047
PM 1847505
DA 2026-03-10
ER

PT J
AU RAMPONE, E
   BOTTAZZI, P
   OTTOLINI, L
AF RAMPONE, E
   BOTTAZZI, P
   OTTOLINI, L
TI COMPLEMENTARY TI AND ZR ANOMALIES IN ORTHO-PYROXENE AND CLINOPYROXENE FROM MANTLE PERIDOTITES
SO NATURE
LA English
DT Article
ID spinel peridotite xenoliths; oceanic upper mantle; rare-earth elements; lithospheric mantle; basalts; rocks; geochemistry; metasomatism; petrology; france
AB FROM the observation that clinopyroxenes in lherzolites from sub-arc, sub-continental and sub-oceanic lithosphere are depleted in titanium and zirconium Salters and Shimizu 1 inferred the existence of a worldwide layer in the upper mantle depleted in these 'high-field-strength' elements. This seems inconsistent, however, with the fact that basalts generated in the upper mantle, except in certain restricted environments (related to subduction processes), do not show depletion of these elements. In an attempt to address this conflict, we have used ion-probe measurements to study Ti and Zr abundances in sub-continental spinel peridotites from Liguria, Italy. We confirm the existence of Ti and Zr depletion in clinopyroxenes, but find that these are compensated by enrichment in the coexisting orthopyroxene. The calculated whole-rock abundance patterns therefore show negligible anomalies. We conclude that Ti, Zr and rare-earth abundances in clinopyroxene alone cannot be used to infer the existence of a global mantle layer depleted in high-field-strength elements, a feature that would place important constraints on models of lithospheric growth 2.
C1 MAX PLANCK INST CHEM,W-6500 MAINZ,GERMANY.
   CNR,CTR STUDIO CRISTALLOCHIM & CRISTALLOG,I-27100 PAVIA,ITALY.
C3 Max Planck Society; Consiglio Nazionale delle Ricerche (CNR)
RP RAMPONE, E (corresponding author), UNIV GENOA,DIPARTIMENTO SCI TERRA,CORSO EUROPA 30,I-16132 GENOA,ITALY.
NR 31
TC 124
Z9 132
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 518
EP 520
DI 10.1038/354518a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100012
DA 2026-03-10
ER

PT J
AU SKEWS, BW
AF SKEWS, BW
TI AUTOROTATION OF MANY-SIDED BODIES IN AN AIRSTREAM
SO NATURE
LA English
DT Article
AB AUTOROTATION is the rotation of an object in an airstream in the absence of any other driving force 1. It is important in the fall characteristics of some tree fruits, the growth of hailstones, and the trajectories of objects separating from aircraft and spacecraft. Previous studies have concentrated on thin, flat plates rotating about an axis normal to the airstream, but in many applications - those relating to the free fall of bodies through air - the behaviour of bodies of more complex geometry is of interest. When these autorotate, a lift force is generated which can significantly alter the body's trajectory. Here I examine the autorotation of prisms whose cross-sections are regular polygons. Prisms of triangular section rotate fastest, but generate less lift than a flat plate. Only bodies with less than eight sides are found to show autorotational behaviour. In all of these cases, the lift forces generated are larger than those obtained from a spinning cylinder driven externally at the same rotation speed. Many devices have been proposed in the past that use as a propulsion mechanism the lift force developed on a driven rotating cylinder, perhaps the most spectacular being the Flettner rotorship which crossed the Atlantic in 1926 2. The use of polygonal bodies would have application in these cases, not only because of the higher lift generated but also because the energy required may be derived simply from the relative wind. There are thus also clear implications for wind-power devices.
RP SKEWS, BW (corresponding author), UNIV WITWATERSRAND,SCH MECH ENGN,JOHANNESBURG 2001,SOUTH AFRICA.
NR 10
TC 29
Z9 34
U1 1
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 512
EP 513
DI 10.1038/352512a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600056
DA 2026-03-10
ER

PT J
AU RUDENSKY, AY
   RATH, S
   PRESTONHURLBURT, P
   MURPHY, DB
   JANEWAY, CA
AF RUDENSKY, AY
   RATH, S
   PRESTONHURLBURT, P
   MURPHY, DB
   JANEWAY, CA
TI ON THE COMPLEXITY OF SELF
SO NATURE
LA English
DT Article
ID antigen
AB SELF peptides bound to self major histocompatibility complex (MHC) molecules have been implicated both in positive 1,2 and in negative 3,4 selection of T cells during intrathymic development. We report here that the novel MHC-restricted monoclonal antibody Y-Ae (ref. 5) detects the MHC class II bound form of a major self peptide 6. Y-Ae binds approximately 12% of the relevant MHC class II molecules on self antigen presenting cells. The peptide detected by Y-Ae is one of several major peptides eluted from the MHC molecule 6. These data suggest that self peptides presented by self MHC class II molecules at densities sufficient to signal a CD4 T cell are of very limited complexity. Furthermore, as Y-Ae stains antigen presenting cells that mediate negative selection but not thymic cortical epithelial cells 5 that drive positive selection 3, differential expression of self peptide:self MHC class II complexes may be a key feature of intrathymic selection.
C1 YALE UNIV,SCH MED,IMMUNOBIOL SECT,NEW HAVEN,CT 06510.
   HOWARD HUGHES MED INST,NEW HAVEN,CT 06510.
C3 Yale University; Howard Hughes Medical Institute
NR 11
TC 261
Z9 281
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 660
EP 662
DI 10.1038/353660a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200070
PM 1656278
DA 2026-03-10
ER

PT J
AU CAMERON, DA
   PUGH, EN
AF CAMERON, DA
   PUGH, EN
TI DOUBLE CONES AS A BASIS FOR A NEW TYPE OF POLARIZATION VISION IN VERTEBRATES
SO NATURE
LA English
DT Article
ID orientation; light; patterns; sensitivity; goldfish; retina; fish
AB MANY invertebrates 1-4 and vertebrates 5-14 are sensitive to the polarization of light. The biophysical basis of invertebrate polarization sensitivity is an intrinsic dichroism, the alignment of chromophores along the photoreceptor microvilli 3. But such dichroism to axially propagating light is not present in vertebrate photoreceptors, whose chromophores are free to rotate in the plane of the outer-segment disc membranes, and a biophysical mechanism responsible for vertebrate polarization sensitivity has not been established. We hypothesize that the roughly elliptical cross-sectioned double-cone inner segment acts as a birefringent, polarization-sensitive dielectric waveguide, and that the double cone mosaic generates a 'polarization contrast' neural image. Here we confirm three predictions derived from these hypotheses:  (1) 90-degrees periodicity for polarization sensitivity; (2) polarization sensitivity maxima corresponding to the absolute orientation of the axes of the double-cone inner-segment cross-sections; and (3) action spectrum for polarization sensitivity corresponding to the absorption spectrum of the double cones. We also present evidence for a polarization-opponent neural encoding in vertebrates.
C1 UNIV PENN,SCH ARTS & SCI,DEPT PSYCHOL,PHILADELPHIA,PA 19104.
C3 University of Pennsylvania
RP CAMERON, DA (corresponding author), UNIV PENN,SCH ARTS & SCI,INST NEUROL SCI,3815 WALNUT ST,PHILADELPHIA,PA 19104, USA.
NR 30
TC 102
Z9 112
U1 1
U2 34
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 161
EP 164
DI 10.1038/353161a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100052
PM 1891046
DA 2026-03-10
ER

PT J
AU POWIS, SJ
   TOWNSEND, ARM
   DEVERSON, EV
   BASTIN, J
   BUTCHER, GW
   HOWARD, JC
AF POWIS, SJ
   TOWNSEND, ARM
   DEVERSON, EV
   BASTIN, J
   BUTCHER, GW
   HOWARD, JC
TI RESTORATION OF ANTIGEN PRESENTATION TO THE MUTANT-CELL LINE RMA-S BY AN MHC-LINKED TRANSPORTER
SO NATURE
LA English
DT Article
ID class-i molecules; toxic lymphocytes-t; influenza nucleoprotein; region; association; proteins; peptides; invitro; chains; heavy
AB IN mammalian cells, short peptides derived from intracellular proteins are displayed on the cell membrane associated with class I molecules of the major histocompatibility complex (MHC). The surface presentation of class I-peptide complexes presumably alerts the immune system to intracellular viral protein synthesis. Peptides derived from the cytosol must reach the cisternae of the endoplasmic reticulum where they are required for the assembly of stable class I molecules 1-11, and it has been proposed that the Products of the two MHC-encoded ATP-binding cassette (ABC) transporter genes 12-15 function to deliver the peptides across the membrane of the endoplasmic reticulum. This idea is supported by experiments in which transfection of a human cell line defective in class I expression with a complementary DNA of one of these genes restored cell surface expression levels 16.  Here we show that the complete phenotype of the mouse mutant cell line RMA-S, in which lack of surface expression of stable class I molecules correlates with an inability to present viral peptides originating in the Cytosol 6-10,17, is repaired by the cDNA of the other transporter gene. These results are consistent with the possibility that the two transporter polypeptides form a heterodimer.
C1 JOHN RADCLIFFE HOSP,INST MOLEC MED,MOLEC IMMUNOL GRP,OXFORD OX3 9DU,ENGLAND.
C3 University of Oxford
RP POWIS, SJ (corresponding author), AFRC,INST ANIM PHYSIOL & GENET RES,DEPT IMMUNOL,CAMBRIDGE CB2 4AT,ENGLAND.
NR 27
TC 358
Z9 400
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 528
EP 531
DI 10.1038/354528a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100016
PM 1758495
DA 2026-03-10
ER

PT J
AU HAMPTON, RY
   GOLENBOCK, DT
   PENMAN, M
   KRIEGER, M
   RAETZ, CRH
AF HAMPTON, RY
   GOLENBOCK, DT
   PENMAN, M
   KRIEGER, M
   RAETZ, CRH
TI RECOGNITION AND PLASMA-CLEARANCE OF ENDOTOXIN BY SCAVENGER RECEPTORS
SO NATURE
LA English
DT Article
ID low-density-lipoprotein; escherichia-coli lipopolysaccharide; a-binding-sites; cholesterol deposition; peritoneal-macrophages; rat-liver; cells; protein; degradation; metabolism
AB LIPID A is the active moiety of lipopolysaccharide (LPS, also referred to as endotoxin), a surface component of Gram-negative bacteria that stimulates macrophage activation and causes endotoxic shock 1,2.  Macrophages can bind, internalize and partially degrade LPS, lipid A and its bioactive precursor, lipid IV(A) (refs 3-7). We report here that lipid IV(A) binding and subsequent metabolism to a less active form by macrophage-like RAW 264.7 cells is mediated by the macrophage scavenger receptor. Scavenger-receptor ligands inhibit lipid IV(A) binding to, and metabolism by, RAW cells, and lipid IV(A) binds to type I and type II bovine scavenger receptors on transfected Chinese hamster ovary cells. Although in vitro competition studies with RAW cells indicate that scavenger receptor binding is not involved in LPS or lipid IV(A)-induced stimulation of macrophages, in vivo studies show that scavenger-receptor ligands greatly inhibit hepatic uptake of lipid IV(A) in mice. Thus, scavenger receptors expressed on macrophages may have an important role in the clearance and detoxification of endotoxin in animals.
C1 MERCK SHARP & DOHME LTD,DEPT BIOCHEM,RAHWAY,NJ 07065.
   MIT,DEPT BIOL,CAMBRIDGE,MA 02139.
C3 Merck & Company; Massachusetts Institute of Technology (MIT)
RP HAMPTON, RY (corresponding author), UNIV WISCONSIN,DEPT BIOCHEM,MADISON,WI 53706, USA.
NR 30
TC 483
Z9 535
U1 0
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 342
EP 344
DI 10.1038/352342a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900073
PM 1852209
DA 2026-03-10
ER

PT J
AU HAPKE, B
   BLEWETT, D
AF HAPKE, B
   BLEWETT, D
TI COHERENT BACKSCATTER MODEL FOR THE UNUSUAL RADAR REFLECTIVITY OF ICY SATELLITES
SO NATURE
LA English
DT Article
AB RADAR is a powerful technique for probing the surfaces and subsurfaces of Solar System bodies. Inner Solar System bodies reflect radar in an almost specular fashion, with low reflectivity and little polarization. The icy satellites of Jupiter, by contrast, show high reflectivities, diffuse scattering laws and unusual polarization properties 1: compared with what would be expected for specular reflection, there is 1.5 times as much power reflected in the unexpected sense of circularly polarized radar as in the expected sense, and half as much power in the unexpected as in the expected sense of linear polarization. According to the coherent backscatter model 2, most of the received power from icy satellites is multiply reflected by particles about a wavelength in size located randomly under the surface of the regolith. We have constructed a laboratory analogue of this model by reflecting laser light off polystyrene beads suspended in water, and find that this model reproduces the unusual polarization ratios observed in the radar data. This implies that the regoliths of icy satellites are weakly absorbing matrices of small refractive index containing imbedded scatterers separated by distances of the order of a wavelength. No structures of special shape or other geometrical or optical properties are required.
RP HAPKE, B (corresponding author), UNIV PITTSBURGH,DEPT GEOL & PLANETARY SCI,321 OLD ENGN HALL,PITTSBURGH,PA 15260, USA.
NR 15
TC 39
Z9 39
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 46
EP 47
DI 10.1038/352046a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800063
DA 2026-03-10
ER

PT J
AU MACKINNON, R
AF MACKINNON, R
TI DETERMINATION OF THE SUBUNIT STOICHIOMETRY OF A VOLTAGE-ACTIVATED POTASSIUM CHANNEL
SO NATURE
LA English
DT Article
ID charybdotoxin block; k+ channels; drosophila; inhibitor; junction
AB The voltage-activated K+, Na+ and Ca2+ channels are responsible for the generation and propagation of electrical signals in cell membranes.  The K+ channels are multimeric membrane proteins formed by the aggregation of an unknown number of independent subunits 1-3.  By studying the interaction of a scorpion toxin with coexpressed wild-type and toxin-insensitive mutant Shaker K+ channels, the subunit stoichiometry can be determined.  The Shaker K+ channel is found to have a tetrameric structure.  This is consistent with the sequence relationship between a K+ channel and each of the four internally homologous repeats of Na+ and Ca2+ channels 4-6.
RP MACKINNON, R (corresponding author), HARVARD UNIV,SCH MED,DEPT CELLULAR & MOLEC PHYSIOL,25 SHATTUCK ST,BOSTON,MA 02115, USA.
NR 23
TC 830
Z9 925
U1 0
U2 47
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 232
EP 235
DI 10.1038/350232a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900058
PM 1706481
DA 2026-03-10
ER

PT J
AU DEVOL, AH
AF DEVOL, AH
TI DIRECT MEASUREMENT OF NITROGEN GAS FLUXES FROM CONTINENTAL-SHELF SEDIMENTS
SO NATURE
LA English
DT Article
ID organic-matter; marine-sediments; denitrification; sea; nitrification; water; mineralization; diagenesis; oxidation; reduction
AB It has been suggested that denitrification in continental shelf and slope sediments is the most important sink in the marine nitrogen cycle 1-4.  This conclusion has been reached, not from direct measurements of denitrification in these areas, but rather from indirect estimates derived from pore-water models of diagenetic processes.  In highly bioturbated continental shelf and slope sediments with steep pore-water gradients, such indirect estimates may not be applicable 5,6.  I have now made direct, in situ measurements of denitrification in sediments of the eastern North Pacific continental margin by determining the flux of molecular nitrogen out of the sediments into the overlying water.  Denitrification rates in continental shelf sediments measured in this fashion averaged 3.7 pmol N cm-2 s-1.  The flux of nitrate from the overlying water into the sediments was only 1.5 pmol N cm-2 s-1, showing that most of the nitrogen gas production is coupled to nitrification within the sediments.  The denitrification rates observed here are four to five times those estimated previously by indirect methods for these same sediments, and indicate the limitations of such indirect estimates.  My results suggest that the global denitrification rate in shelf and slope sediments may be greater than previously thought, and confirm the importance of sedimentary denitrification in the marine nitrogen budget.
RP DEVOL, AH (corresponding author), UNIV WASHINGTON,SCH OCEANOG,WB-10,SEATTLE,WA 98195, USA.
NR 30
TC 162
Z9 183
U1 0
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 319
EP 321
DI 10.1038/349319a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100048
DA 2026-03-10
ER

PT J
AU DALICHAOUCH, R
   ARMSTRONG, JP
   SCHULTZ, S
   PLATZMAN, PM
   MCCALL, SL
AF DALICHAOUCH, R
   ARMSTRONG, JP
   SCHULTZ, S
   PLATZMAN, PM
   MCCALL, SL
TI MICROWAVE LOCALIZATION BY 2-DIMENSIONAL RANDOM SCATTERING
SO NATURE
LA English
DT Article
ID weak localization; photons; media
AB WAVEFUNCTIONS of electrons or photons in a strongly scattering random medium may become localized owing to the underlying wave nature of the particles 1,2.  Particularly surprising and counter-intuitive is the prediction that, under appropriate conditions, scatterers placed randomly in space will always produce fully localized states-that is, an energy distribution of the normal modes whose envelope decays exponentially in all directions. In consequence, energy at the resonant frequency of a localized mode, injected into that mode's region of space, cannot diffuse away, but remains trapped until dissipated. Here we report measurements of the electric-field energy density for microwave radiation localized in essentially two-dimensional space by scattering from a random array of dielectric cylinders placed between a pair of parallel conducting plates. We detect regions of high energy density representing the signature of localized modes. The available range of measured variables, scattering materials and cylinder configurations offer the opportunity to provide quantitative answers to important general questions about strong localization. In particular, a better understanding of two-dimensional localization raises the possibility of using localized-mode resonances as a diagnostic tool for situations in which localization phenomenon may occur naturally 3-for example, in investigations of the internal distribution of media and defects in geological strata, under-ocean topology or electronic thin films, all of which may exhibit pseudo-two-dimensional characteristics.
C1 AT&T BELL LABS,MURRAY HILL,NJ 07974.
C3 AT&T; Nokia Corporation; Nokia Bell Labs
RP DALICHAOUCH, R (corresponding author), UNIV CALIF SAN DIEGO,9500 GILMAN DR,LA JOLLA,CA 92093, USA.
NR 18
TC 232
Z9 260
U1 0
U2 30
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 53
EP 55
DI 10.1038/354053a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900054
DA 2026-03-10
ER

PT J
AU PERROT, V
   RICHERD, S
   VALERO, M
AF PERROT, V
   RICHERD, S
   VALERO, M
TI TRANSITION FROM HAPLOIDY TO DIPLOIDY
SO NATURE
LA English
DT Article
ID dominance
AB AS a direct consequence of sex, organisms undergo a haploid and a diploid stage during their life cycle. Although the relative duration of haploid and diploid phases varies greatly among taxa, the diploid phase is more conspicuous in all higher organisms. Therefore it is widely believed that diploidy offers more evolutionary possibilities 1-3 and is thus nearly always selected for. We have now performed computer simulations to investigate one possible advantage of diploidy, that is, protection against the expression of deleterious mutations. Instead of comparing isolated haploid and diploid populations, we considered interbreeding haploids and diploids. Diploids invaded the population only when the dominance degree of a single deleterious mutation was smaller than about 1/2, and the condition allowing diploidy to invade depended on how harmful the mutation was.
C1 UNIV SCI & TECHNOL LILLE FLANDRES ARTOIS, GENET & EVOLUT POPULAT VEGETALES LAB, CNRS, URA 1185, F-59655 VILLENEUVE DASCQ, FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS); Universite de Lille
RP PERROT, V (corresponding author), UNIV BASEL, INST ZOOL, RHEINSPRUNG 9, CH-4051 BASEL, SWITZERLAND.
NR 14
TC 112
Z9 122
U1 0
U2 9
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 315
EP 317
DI 10.1038/351315a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600060
PM 2034274
DA 2026-03-10
ER

PT J
AU WOODS, AW
   WOHLETZ, K
AF WOODS, AW
   WOHLETZ, K
TI DIMENSIONS AND DYNAMICS OF CO-IGNIMBRITE ERUPTION COLUMNS
SO NATURE
LA English
DT Article
ID explosive volcanic-eruptions; pyroclastic flows; plinian eruptions; dispersal; ash; generation; fall; dust
AB Very powerful volcanic eruptions cannot always form classical Plinian eruption columns 1-4. Instead, collapsing fountains may develop above the vent and shed pyroclastic flows which spread laterally along the ground 5. The upper part of these hot, dense pyroclastic flows may become buoyant through the entrainment, heating and expansion of ambient air, coupled with the sedimentation of larger clasts suspended in the flow. The buoyant material may rise, in a co-ignimbrite eruption column, carrying massive quantities of fine dust and volatiles into the stratosphere 6,7. Here we present a model of this process, and show that the co-ignimbrite columns associated with the eruptions of Toba 8,9 75,000 years ago and Tambora 10 in 1815 may have ascended only about 32 and 23 km; the latter is comparable with the less powerful 1982 Plinian eruption column of El Chichon 11. This corroborates arguments that the mass of sulphuric acid aerosols injected into the stratosphere and not the eruptive power determines the climatic impact of an eruption 12,13.
C1 UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, INST GEOPHYS & PLANETARY PHYS, LA JOLLA, CA 92093 USA.
   UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA.
C3 University of California System; University of California San Diego; Scripps Institution of Oceanography; United States Department of Energy (DOE); Los Alamos National Laboratory
NR 27
TC 105
Z9 114
U1 1
U2 15
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 225
EP 227
DI 10.1038/350225a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900055
DA 2026-03-10
ER

PT J
AU STEINMEYER, K
   ORTLAND, C
   JENTSCH, TJ
AF STEINMEYER, K
   ORTLAND, C
   JENTSCH, TJ
TI PRIMARY STRUCTURE AND FUNCTIONAL EXPRESSION OF A DEVELOPMENTALLY REGULATED SKELETAL-MUSCLE CHLORIDE CHANNEL
SO NATURE
LA English
DT Article
ID sodium-channel; acetylcholine-receptor; torpedo electroplax; selective channels; messenger-rnas; rat muscle; conductance
AB SKELETAL muscle is unusual in that 70-85% of resting membrane conductance is carried by chloride ions 1. This conductance is essential for membrane-potential stability, as its block by 9-anthracene-carboxylic acid and other drugs causes myotonia 2,3. Fish electric organs are developmentally derived from skeletal muscle, suggesting that mammalian muscle may express a homologue of the Torpedo mamorata electroplax chloride channel 4,5. We have now cloned the complementary DNA encoding a rat skeletal muscle chloride channel by homology screening to the Cl- channel from Torpedo 4 (Fig. 1a). It encodes a 994-amino-acid protein which is about 54% identical to the Torpedo channel and is predominantly expressed in skeletal muscle. Messenger RNA amounts in that tissue increase steeply in the first 3-4 weeks after birth, in parallel with the increase in muscle Cl- conductance 6. Expression from cRNA in Xenopus oocytes leads to 9-anthracene-carboxylic acid-sensitive currents with time and voltage dependence typical for macroscopic muscle Cl- conductance. This and the functional destruction of this channel in mouse myotonia 7 suggests that we have cloned the major skeletal muscle chloride channel.
C1 UNIV HAMBURG,CTR MOLEC NEUROBIOL,MARTINISTR 52,W-2000 HAMBURG 20,GERMANY.
C3 University of Hamburg
NR 24
TC 401
Z9 424
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 301
EP 304
DI 10.1038/354301a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400046
PM 1659664
DA 2026-03-10
ER

PT J
AU GYLLENSTEN, U
   WHARTON, D
   JOSEFSSON, A
   WILSON, AC
AF GYLLENSTEN, U
   WHARTON, D
   JOSEFSSON, A
   WILSON, AC
TI PATERNAL INHERITANCE OF MITOCHONDRIAL-DNA IN MICE
SO NATURE
LA English
DT Article
ID maternal inheritance; chain-reaction; polymerase; drosophila; evolution; deletions; sequence; strains
AB FOR nearly 20 years it has been assumed on the basis of low-resolution experiments that mitochondrial (mt)DNA, in contrast to the genes in the nucleus, has an exclusively maternal mode of inheritance in animals 1. Using the polymerase chain reaction 2-3, paternally inherited mtDNA molecules have now been detected in mice at a frequency of 10(-4), relative to the maternal contributions. These mice were hybrids between two inbred strains (C57BL/6J and Mus spretus) whose mtDNAs can be distinguished easily. This new mode of inheritance provides a mechanism for generating heteroplasmy and may explain mitochondrial disorders exhibiting biparental transmission.
C1 NEW YORK ZOOL SOC,BRONX,NY 10460.
   FORDHAM UNIV,DEPT BIOL SCI,BRONX,NY 10458.
   UNIV CALIF BERKELEY,DIV BIOCHEM & MOLEC BIOL,BERKELEY,CA 94720.
C3 Wildlife Conservation Society; Fordham University; University of California System; University of California Berkeley
RP GYLLENSTEN, U (corresponding author), UNIV UPPSALA,CTR BIOMED,DEPT MED GENET,BOX 589,S-75123 UPPSALA,SWEDEN.
NR 19
TC 499
Z9 562
U1 0
U2 30
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 255
EP 257
DI 10.1038/352255a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500071
PM 1857422
DA 2026-03-10
ER

PT J
AU TSUKAMOTO, T
   MIURA, S
   FUJIKI, Y
AF TSUKAMOTO, T
   MIURA, S
   FUJIKI, Y
TI RESTORATION BY A 35K MEMBRANE-PROTEIN OF PEROXISOME ASSEMBLY IN A PEROXISOME-DEFICIENT MAMMALIAN-CELL MUTANT
SO NATURE
LA English
DT Article
ID rat-liver peroxism; endoplasmic-reticulum; zellweger syndrome; carboxy terminus; polypeptide; envelope; genome
AB PEROXISOMES are among the intracellular organelles of eukaryotic cells that contain specialized sets of enzymes with specific functions 1.  Little is known of membranous components involved in assembly of the intracellular compartments 2-5.  We isolated two peroxisome-deficient and mutually complementary, Chinese hamster ovary cell mutants, Z65 and Z24 6, which closely resembled fibroblasts from patients with autosomal recessive, peroxisome-defective disorders such as Zellweger syndrome 1,7.  These patients show characteristic dysmorphism, severe hypotonia, psychomotor retardation, and peroxisomal dysfunctions and rarely survive early childhood.  Here we report what seems to be the first direct cloning and characterization of a complementary DNA encoding a peroxisomal membrane protein of relative molecular mass 35,000 (M(r) 35K) that restores the biogenesis of peroxisomes and complements the defect of peroxisomal functions in the mutant Z65.
C1 MEIJI INST HLTH SCI,MOLEC CELL BIOL LAB,ODAWARA,KANAGAWA 250,JAPAN.
NR 29
TC 225
Z9 229
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 77
EP 81
DI 10.1038/350077a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300070
PM 1750930
DA 2026-03-10
ER

PT J
AU BLUNDY, JD
   BRODHOLT, JP
   WOOD, BJ
AF BLUNDY, JD
   BRODHOLT, JP
   WOOD, BJ
TI CARBON FLUID EQUILIBRIA AND THE OXIDATION-STATE OF THE UPPER MANTLE
SO NATURE
LA English
DT Article
ID oxygen fugacity; basaltic magmas; fe-57 mossbauer; heat-flow
AB It has been proposed that the oxidation state of the Earth's upper mantle is buffered by C-O fluids in equilibrium with elemental carbon 1,2.  A large body of data on the oxygen fugacities (f(O2) recorded by mantle rocks and their derivative melts now allows us to test this proposal.  By comparing the measured f(O2) values with those calculated for carbon-CO2-CO-carbonate equilibria along appropriate mantle geotherms, we find the data to be wholly consistent with this hypothesis.  Moreover, the calculated variation of f(O2) with temperature and pressure accounts for much of the observed correlation between the oxidation state of mantle samples and their tectonic provenance 3,4.  The apparent buffering of mantle f(O2) requires modest quantities of mantle carbon and fluid, which do not exceed independently estimated values.  The proposal is not compromised if parts of the mantle are fluid-undersaturated, or if the C-O fluid phase is diluted by other volatiles.
RP BLUNDY, JD (corresponding author), UNIV BRISTOL,DEPT GEOL,WILLS MEM BLDG,BRISTOL BS8 1RJ,ENGLAND.
NR 36
TC 78
Z9 86
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 321
EP 324
DI 10.1038/349321a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100049
DA 2026-03-10
ER

PT J
AU HATTA, K
   KIMMEL, CB
   HO, RK
   WALKER, C
AF HATTA, K
   KIMMEL, CB
   HO, RK
   WALKER, C
TI THE CYCLOPS MUTATION BLOCKS SPECIFICATION OF THE FLOOR PLATE OF THE ZEBRAFISH CENTRAL-NERVOUS-SYSTEM
SO NATURE
LA English
DT Article
ID embryo; cells
AB THE floor plate is a set of epithelial cells present in the ventral midline of the neural tube in vertebrates 1 that seems to have an important role in the developmental patterning 2 of central nervous system fibre pathways 3,4, and arrangements of specific neurons 5. The floor plate arises from dorsal ectodermal cells closely associated with the mesoderm that forms notochord 6, and it may depend on interactions from the notochord for its specification. To learn the nature of these interactions we have analysed mutations in zebrafish (Brachydanio rerio). We report here that in wild-type embryos the floor plate develops as a simply organized single cell row, but that its development fails in embryos bearing the newly discovered zygotic lethal 'cyclops' mutation, cyc-1(b16). Mosaic analysis establishes that cyc-1 blocks floor plate development autonomously and reveals the presence of homeogenetic induction between floor plate cells.
RP HATTA, K (corresponding author), UNIV OREGON, INST NEUROSCI, EUGENE, OR 97403 USA.
NR 27
TC 392
Z9 429
U1 0
U2 7
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 339
EP 341
DI 10.1038/350339a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800092
PM 2008211
DA 2026-03-10
ER

PT J
AU WESTWOOD, JT
   CLOS, J
   WU, C
AF WESTWOOD, JT
   CLOS, J
   WU, C
TI STRESS-INDUCED OLIGOMERIZATION AND CHROMOSOMAL RELOCALIZATION OF HEAT-SHOCK FACTOR
SO NATURE
LA English
DT Article
ID dna-binding property; drosophila-melanogaster; transcription factor; rna-polymerase; proteins; invitro; gene; activation; localization; upstream
AB The induction of heat-shock transcription factor (HSF) binding to DNA is accomplished by a heat-induced oligomerization. The transition to the induced state is accompanied by a chromosomal redistribution of HSF to the heat-shock puff sites. Over 150 additional chromosomal sites also accumulate HSF, including developmental loci that are repressed during heat shock. These findings suggest an unforeseen role for HSF as a repressor of normal gene activity during heat stress.
RP WESTWOOD, JT (corresponding author), NCI, BIOCHEM LAB, BG 37, RM 4C-09, BETHESDA, MD 20892 USA.
NR 56
TC 323
Z9 362
U1 0
U2 26
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 822
EP 823
DI 10.1038/353822a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200051
PM 1944557
DA 2026-03-10
ER

PT J
AU STRAUSFELD, U
   LABBE, JC
   FESQUET, D
   CAVADORE, JC
   PICARD, A
   SADHU, K
   RUSSELL, P
   DOREE, M
AF STRAUSFELD, U
   LABBE, JC
   FESQUET, D
   CAVADORE, JC
   PICARD, A
   SADHU, K
   RUSSELL, P
   DOREE, M
TI DEPHOSPHORYLATION AND ACTIVATION OF A P34CDC2 CYCLIN-B COMPLEX INVITRO BY HUMAN CDC25 PROTEIN
SO NATURE
LA English
DT Article
ID m-phase; fission yeast; tyrosine phosphorylation; periodic activation; possible mechanism; mitotic inducer; kinase; purification; starfish; mitosis
AB OOCYTES arrested in the G2 phase of the cell cycle contain a p34cdc2/cyclin B complex which is kept in an inactive form by phosphorylation of its p34cdc2 subunit on tyrosine, threonine and perhaps serine residues (see refs 1 and 2 for review). The phosphatase(s) involved in p34cdc2 dephosphorylation is unknown, but the product of the fission yeast cdc25+ gene 3,4, and its homologues in budding yeast 5 and Drosophila 6 are probably positive regulators of the transition from G2 to M phase. We have purified the inactive p34cdc2/cyclin B complex from G2-arrested starfish oocytes. Addition of the purified bacterially expressed product of the human homologue of the fission yeast cdc25+ gene 7 (p54CDC25H) triggers p34cdc2 dephosphorylation and activates H1 histone kinase activity in this preparation. We propose that the cdc25+ gene product directly activates the p34cdc2-cyclin B complex.
C1 LAB ARAGO, F-66650 BANYULS SUR MER, FRANCE.
   Scripps Res Inst, RES INST, DEPT MOLEC BIOL, LA JOLLA, CA 92037 USA.
   INSERM, F-34033 MONTPELLIER, FRANCE.
C3 Scripps Research Institute; Institut National de la Sante et de la Recherche Medicale (Inserm); Universite de Montpellier
RP STRAUSFELD, U (corresponding author), CNRS, BP 5051, F-34033 MONTPELLIER, FRANCE.
NR 21
TC 542
Z9 601
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 242
EP 245
DI 10.1038/351242a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000060
PM 1828290
DA 2026-03-10
ER

PT J
AU CROTTS, APS
   HEATHCOTE, SR
AF CROTTS, APS
   HEATHCOTE, SR
TI VELOCITY STRUCTURE OF THE RING NEBULA AROUND SUPERNOVA-1987A
SO NATURE
LA English
DT Article
ID progenitor; sn-1987a; 1987a
AB THE optical fading of supernova 1987 A has revealed a parsec-sized nebula glowing in narrow atomic lines.  The emission is presumed to come from circumstellar material, shed during the life of the progenitor star, illuminated by the ultraviolet flash from the explosion.  This material is the closest to the supernova site that has been detected (apart from some transient radio emission immediately after the explosion 1) and therefore represents the youngest pre-supernova structure available for study.  Here we report a series of high-resolution spectra of the nebulosity.  The hollow, 1.7-arcsec-wide nebula has the velocity field of a ring expanding at 10.3 km s-1, not that of a limb-brightened spheroid.  Fainter nebulosity within 3 arcsec is expanding slightly faster, as indicated by redshifted emission from behind the supernova.  The geometry of the emission can be used to infer structure, provided that light travel time and recombination delays are accounted for.  Our analysis sets an upper limit to the velocity of the wind from the progenitor during its red supergiant (RSG) phase, and implies an RSG lifetime of < 4 x 10(5) yr and an interval of approximately 2 x 10(4) yr between the end of the RSG phase and the supernova explosion.
C1 CERRO TOLOLO INTERAMER OBSERV,LA SERENA 1353,CHILE.
C3 National Optical Astronomy Observatory; Cerro Tololo Inter-American Observatory
RP CROTTS, APS (corresponding author), COLUMBIA UNIV,DEPT ASTRON,NEW YORK,NY 10027, USA.
NR 12
TC 91
Z9 92
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 683
EP 685
DI 10.1038/350683a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000051
DA 2026-03-10
ER

PT J
AU JAUNCEY, DL
   REYNOLDS, JE
   TZIOUMIS, AK
   MUXLOW, TWB
   PERLEY, RA
   MURPHY, DW
   PRESTON, RA
   KING, EA
   PATNAIK, AR
   JONES, DL
   MEIER, DL
   BIRD, DJ
   BLAIR, DG
   BUNTON, JD
   CLAY, RW
   COSTA, ME
   DUNCAN, RA
   FERRIS, RH
   GOUGH, RG
   HAMILTON, PA
   HOARD, DW
   KEMBALL, A
   KESTEVEN, MJ
   LOBDELL, ET
   LUITEN, AN
   MCCULLOCH, PM
   MURRAY, JD
   NICOLSON, GD
   RAO, AP
   SAVAGE, A
   SINCLAIR, MW
   SKJERVE, L
   TAAFFE, L
   WARK, RM
   WHITE, GL
AF JAUNCEY, DL
   REYNOLDS, JE
   TZIOUMIS, AK
   MUXLOW, TWB
   PERLEY, RA
   MURPHY, DW
   PRESTON, RA
   KING, EA
   PATNAIK, AR
   JONES, DL
   MEIER, DL
   BIRD, DJ
   BLAIR, DG
   BUNTON, JD
   CLAY, RW
   COSTA, ME
   DUNCAN, RA
   FERRIS, RH
   GOUGH, RG
   HAMILTON, PA
   HOARD, DW
   KEMBALL, A
   KESTEVEN, MJ
   LOBDELL, ET
   LUITEN, AN
   MCCULLOCH, PM
   MURRAY, JD
   NICOLSON, GD
   RAO, AP
   SAVAGE, A
   SINCLAIR, MW
   SKJERVE, L
   TAAFFE, L
   WARK, RM
   WHITE, GL
TI AN UNUSUALLY STRONG EINSTEIN RING IN THE RADIO-SOURCE PKS1830-211
SO NATURE
LA English
DT Article
AB RADIO observations of the strong, flat-spectrum radio source PKS1830-211 revealed a double structure, with a separation of 1 arcsec, suggesting that it might be a gravitationally lensed object 1.  We have now obtained high-resolution radio images of PKS1830-211 from several interferometric radiotelescope networks, which show an unusual elliptical ring-like structure connecting the two brighter components.  The presence of the ring, and the similarity of the two brighter spots, argue strongly that this is indeed a gravitationally lensed system, specifically an Einstein ring in which lens and lensed object are closely aligned.  Although the source is close to the galactic plane, it seems that both the lens and background (lensed) object are extragalactic.  This object is one hundred times brighter than either of the two previously discovered radio Einstein rings, and is among the six brightest flat-spectrum sources in the sky.  Its brightness makes it a peculiar object:  it must involve either a chance alignment of a lensing object with an unusually bright background source, or an alignment with a less bright object but amplified to an unusual degree.
C1 MT STROMLO & SIDING SPRING OBSERV,CANBERRA,ACT 2611,AUSTRALIA.
   NUFFIELD RADIO ASTRON LAB,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND.
   NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801.
   UNIV TASMANIA,DEPT PHYS,HOBART,TAS 7001,AUSTRALIA.
   UNIV WESTERN AUSTRALIA,DEPT PHYS,NEDLANDS,WA 6009,AUSTRALIA.
   HARTEBEESTHOEK RADIO ASTRON OBSERV,JOHANNESBURG,SOUTH AFRICA.
   TATA INST FUNDAMENTAL RES,CTR RADIO ASTRON,UDHAGAMANDALAM 643001,INDIA.
   ANGLO AUSTRALIAN OBSERV,UK SCHMIDT TELESCOPE UNIT,COONABARABRAN,NSW 2857,AUSTRALIA.
   CALTECH,JET PROP LAB,PASADENA,CA 91109.
   UNIV ADELAIDE,DEPT PHYS,ADELAIDE,SA 5001,AUSTRALIA.
   CSIRO,DIV RADIOPHYS,EPPING,NSW 2121,AUSTRALIA.
C3 Australian National University; University of Manchester; National Radio Astronomy Observatory (NRAO); University of Tasmania; University of Western Australia; National Research Foundation - South Africa; Hartebeesthoek Radio Astronomy Observatory; Tata Institute of Fundamental Research (TIFR); National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; Adelaide University; University of Adelaide; Commonwealth Scientific & Industrial Research Organisation (CSIRO)
RP JAUNCEY, DL (corresponding author), CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA.
NR 17
TC 119
Z9 123
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 132
EP 134
DI 10.1038/352132a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700046
DA 2026-03-10
ER

PT J
AU JEFFREYS, AJ
   MACLEOD, A
   TAMAKI, K
   NEIL, DL
   MONCKTON, DG
AF JEFFREYS, AJ
   MACLEOD, A
   TAMAKI, K
   NEIL, DL
   MONCKTON, DG
TI MINISATELLITE REPEAT CODING AS A DIGITAL APPROACH TO DNA TYPING
SO NATURE
LA English
DT Article
AB Most DNA typing systems used in forensic and legal medicine assay allelic length variation at tandem repetitive DNA regions such as minisatellites. A simple alternative approach that displays patterns of variant repeat units along minisatellite alleles is described here. This produces DNA profiles as extraordinarily variable digital sequences appropriate for forensic investigations, including computer databasing, and for analysing allele diversity and the role of recombination in minisatellite instability.
RP JEFFREYS, AJ (corresponding author), UNIV LEICESTER, DEPT GENET, UNIV RD, LEICESTER LE1 7RH, ENGLAND.
NR 34
TC 367
Z9 409
U1 1
U2 16
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 204
EP 209
DI 10.1038/354204a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800040
PM 1961248
DA 2026-03-10
ER

PT J
AU FELGNER, PL
   RHODES, G
AF FELGNER, PL
   RHODES, G
TI GENE THERAPEUTICS
SO NATURE
LA English
DT Article
ID foreign gene; expression; invivo; dna; delivery; transfection; virus; liver; mice
RP FELGNER, PL (corresponding author), VICAL INC,DIV GENE THERAPEUT,9373 TOWNE CTR DR,SAN DIEGO,CA 92121, USA.
NR 24
TC 203
Z9 262
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 351
EP 352
DI 10.1038/349351a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100060
PM 1987492
DA 2026-03-10
ER

PT J
AU MATESE, JJ
   WHITMAN, PG
   WHITMIRE, DP
AF MATESE, JJ
   WHITMAN, PG
   WHITMIRE, DP
TI GRAVITATIONALLY UNBOUND COMETS MOVE IN PREDOMINANTLY RETROGRADE ORBITS
SO NATURE
LA English
DT Article
ID galactic tidal field; oort cloud comets; original orbits; solar-system; showers; infall; forces
AB COMETS are presumed to enter the inner Solar System from the Oort cloud, a repository of comets more than 10(4) AU from the Sun. Provided the perturbing effects of planetary encounters are taken into account, the original orbital energy of a comet can be calculated, and is negative or positive according to whether the comet's orbit is bound or unbound. The Oort effect 1 is the tendency for the original energies of long-period (> 200-yr) comets to fall within a narrow range:  about 25% of such comets have original energies in the upper 0.2% of the total energy range. In addition, 10% of long-period comets are unbound, and it has been found 2 that positive original energy correlates with distance of closest approach to the Sun. We report here a further correlation:  unbound comets are more likely to move in retrograde orbits. We suggest that this anomaly comes about because of the omission from the orbital energy determination of non-gravitational effects arising from enhanced volatility.
RP MATESE, JJ (corresponding author), UNIV SW LOUISIANA,DEPT PHYS,LAFAYETTE,LA 70504, USA.
NR 20
TC 8
Z9 8
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 506
EP 508
DI 10.1038/352506a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600053
DA 2026-03-10
ER

PT J
AU DIFRANCESCO, D
   TORTORA, P
AF DIFRANCESCO, D
   TORTORA, P
TI DIRECT ACTIVATION OF CARDIAC-PACEMAKER CHANNELS BY INTRACELLULAR CYCLIC-AMP
SO NATURE
LA English
DT Article
ID sino-atrial node; dependent protein-kinase; current if; phosphorylation; myocytes; modulation; neurons; heart; acetylcholine; conductance
AB CYCLIC AMP acts as a second messenger in the modulation of several ion channels 1-9 that are typically controlled by a phosphorylation process 10.  In cardiac pacemaker cells, adrenaline and acetylcholine regulate the hyperpolarization-activated current (i(f)), but in opposite ways; this current is involved in the generation and modulation of pacemaker activity 11.  These actions are mediated by cAMP and underlie control of spontaneous rate by neurotransmitters 12-17.  Whether the cAMP modulation of i(f) is mediated by channel phosphorylation is, however, still unknown.  Here we investigate the action of cAMP on i(f) in excised patches of cardiac pacemaker cells and find that cAMP activates i(f) by a mechanism independent of phosphorylation, involving a direct interaction with the channels at their cytoplasmic side.  Cyclic AMP activates i(f) by shifting its activation curve to more positive voltages, in agreement with whole-cell results.  This is the first evidence of an ion channel whose gating is dually regulated by voltage and direct cAMP binding.
RP DIFRANCESCO, D (corresponding author), UNIV MILAN,DIPARTIMENTO FISIOL & BIOCHIM GEN,VIA CELORIA 26,I-20133 MILAN,ITALY.
NR 30
TC 704
Z9 781
U1 0
U2 37
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 145
EP 147
DI 10.1038/351145a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500050
PM 1709448
DA 2026-03-10
ER

PT J
AU SCOTTI, JV
   RABINOWITZ, DL
   MARSDEN, BG
AF SCOTTI, JV
   RABINOWITZ, DL
   MARSDEN, BG
TI NEAR MISS OF THE EARTH BY A SMALL ASTEROID
SO NATURE
LA English
DT Article
AB THE 0.91-m Spacewatch Telescope, on Kitt Peak in Arizona, is being used to search for new Earth-approaching asteroids. On the night of 18 January 1991 a streaked image extending over more than 161 arcseconds was recorded. Further observations over the next 4.6 hours showed that the images were of an object travelling in an independent orbit around the Sun; it was given the asteroidal designation 1991 BA. Orbital computations, presented here, indicate that 1991 BA was only 0.0053 AU from the Earth at the time of discovery, closing to 0.0033 AU at the last detection. Extrapolation of the calculated orbit shows that the object passed only 0.0011 AU (170,000 km) from the Earth 12 hours after it was found. The observed brightness translates into an absolute visual magnitude 28.9, corresponding to a diameter of only 5-10 m. 1991 BA is the closest and smallest asteroid yet observed outside the Earth's atmosphere.
C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138.
C3 Smithsonian Astrophysical Observatory; Smithsonian Institution; Harvard University
RP SCOTTI, JV (corresponding author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA.
NR 12
TC 19
Z9 20
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 287
EP 289
DI 10.1038/354287a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400040
DA 2026-03-10
ER

PT J
AU JEANLOZ, R
   GODWAL, BK
   MEADE, C
AF JEANLOZ, R
   GODWAL, BK
   MEADE, C
TI STATIC STRENGTH AND EQUATION OF STATE OF RHENIUM AT ULTRA-HIGH PRESSURES
SO NATURE
LA English
DT Article
ID yield strength; mbar; nacl; gpa
AB YIELDING of materials is not understood well enough for detailed, quantitative predictions of strength to be possible, except by using semi-empirical models 1,2. Studies of material strength at high pressures are therefore of fundamental as well as practical interest for determining the relationship between strength and other physical properties3-6. To this end, we have measured the shear stress (tau) supported by rhenium at pressures of up to 120 GPa, far higher than the pressures used in previous studies. Rhenium is of particular interest because it has the highest known bulk and shear moduli among metallic elements 7-9. By using two independent methods determining shear stress at room temperature, we find that rhenium is one of the strongest polycrystalline materials investigated so far, with shear stresses at high pressures reaching tau/mu almost-equal-to 0.04 (+/- 0.02) relative to the shear modulus-mu. These values of tau/mu are nevertheless compatible with current theoretical expectations, indicating that the high strength of rhenium is not anomalous 1,2,6.
C1 BHABHA ATOM RES CTR, DIV NEUTRON PHYS, BOMBAY 400085, INDIA.
C3 Bhabha Atomic Research Center (BARC)
RP JEANLOZ, R (corresponding author), UNIV CALIF BERKELEY, DEPT GEOL & GEOPHYS, BERKELEY, CA 94720 USA.
NR 26
TC 79
Z9 87
U1 0
U2 33
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 687
EP 689
DI 10.1038/349687a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700044
DA 2026-03-10
ER

PT J
AU ROSSI, G
   JIANG, Y
   NEWMAN, AP
   FERRONOVICK, S
AF ROSSI, G
   JIANG, Y
   NEWMAN, AP
   FERRONOVICK, S
TI DEPENDENCE OF YPT1 AND SEC4 MEMBRANE ATTACHMENT ON BET2
SO NATURE
LA English
DT Article
ID ras proteins; yeast; secretion; binding; suppression; mutants; genes
AB MANY small GTP-binding proteins are synthesized as soluble proteins that are post-translationally modified as a prerequisite for membrane attachment 1.  Ypt1 and Sec4 are homologous Raslike GTP-binding proteins that have been proposed to regulate the specificity of vesicular traffic at different stages of the secretory pathway by cycling on and off membranes 2-6.  Here we show that BET2, initially identified as a gene required for transport from endoplasmic reticulum to Golgi apparatus in yeast 7, encodes a factor that is needed for the membrane attachment of Ypt1 and Sec4.  DNA sequence analysis has revealed that Bet2 is homologous to Dpr1 (Ram1), an essential component of a protein prenyltransferase that modifies Ras 8, enabling it to attach to membranes 9,10.  We propose that Bet2 modifies Ypt1 and Sec4 in an analogous manner.
C1 YALE UNIV,SCH MED,DEPT CELL BIOL,333 CEDAR ST,NEW HAVEN,CT 06510.
C3 Yale University
NR 25
TC 103
Z9 112
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 158
EP 161
DI 10.1038/351158a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500055
PM 1903184
DA 2026-03-10
ER

PT J
AU SHOWALTER, MR
AF SHOWALTER, MR
TI VISUAL DETECTION OF 1981S13, SATURNS 18 SATELLITE, AND ITS ROLE IN THE ENCKE GAP
SO NATURE
LA English
DT Article
ID planetary rings; uranian rings; sharp edges; voyager-2; moonlet; system
AB Careful inspection of many images taken by the Voyager spacecraft reveals the presence within the Encke gap of Saturn's eighteenth satellite. Its existence had been inferred from gravitational disturbances seen in Voyager data, and it falls close to the predicted orbit. Its shepherding effect is responsible for keeping the Encke gap open, and it may also be the progenitor of a narrow ringlet within the gap.
RP SHOWALTER, MR (corresponding author), STANFORD UNIV,CTR RADAR ASTRON,STANFORD,CA 94305, USA.
NR 23
TC 95
Z9 97
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 709
EP 713
DI 10.1038/351709a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100052
DA 2026-03-10
ER

PT J
AU GERARD, NP
   GERARD, C
AF GERARD, NP
   GERARD, C
TI THE CHEMOTACTIC RECEPTOR FOR HUMAN-C5A ANAPHYLATOXIN
SO NATURE
LA English
DT Article
ID beta-adrenergic-receptor; c5a receptor; cloning; cdna; c3a
AB HOST defence and inflammatory responses are controlled and amplified by receptor-mediated events often initiated by a chemotactic factor that directs the approach of phagocytic cells 1. Complement receptors CR1 and CR3 are responsible for the phagocytic and adhesive properties of neutrophils 2,3, whereas the C5a receptor mediates the pro-inflammatory and chemotactic actions of the complement anaphylatoxin C5a 4-6. In addition stimulating chemotaxis, granule enzyme release and superoxide anion production, this receptor stimulates upregulation of expression and activity of the adhesion molecule MAC-1, and of CR1, and a decrease in cell-surface glycoprotein 100MEL-14 on neutrophils 7-9. In vivo, the C5a receptor may participate in anaphylactoid and septic shock. The human C5a receptor was cloned from U937 and HL-60 cells and identified by high affinity binding when expressed in COS-7 cells. The deduced amino-acid sequence of the receptor reveals the expected motifs befitting its interaction with cellular GTP-binding proteins.
C1 BETH ISRAEL HOSP, DIV PULM, BOSTON, MA 02215 USA.
   HARVARD UNIV, SCH MED, DEPT MED, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, DEPT PEDIAT, BOSTON, MA 02115 USA.
C3 Harvard University; Harvard University Medical Affiliates; Beth Israel Deaconess Medical Center; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School
RP GERARD, NP (corresponding author), CHILDRENS HOSP MED CTR, INA SUE PERLMUTTER RES LAB, BOSTON, MA 02115 USA.
NR 23
TC 647
Z9 707
U1 0
U2 11
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 614
EP 617
DI 10.1038/349614a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000061
PM 1847994
DA 2026-03-10
ER

PT J
AU STEPHENS, PW
   MIHALY, L
   LEE, PL
   WHETTEN, RL
   HUANG, SM
   KANER, R
   DEIDERICH, F
   HOLCZER, K
AF STEPHENS, PW
   MIHALY, L
   LEE, PL
   WHETTEN, RL
   HUANG, SM
   KANER, R
   DEIDERICH, F
   HOLCZER, K
TI STRUCTURE OF SINGLE-PHASE SUPERCONDUCTING K3C60
SO NATURE
LA English
DT Article
AB RECENT reports 1-3 of superconductivity in alkali-metal-doped compounds of the icosahedral C60 (buckminsterfullerene) molecule have attracted great experimental and theoretical interest.  Superconductivity was originally discovered in samples prepared from gas-solid reactions 1, which made it impossible to determine the composition or structure of the superconducting phase.  Holczer et al. 4 demonstrated that potassium-doped C60 has only a single stable superconducting phase, K3C60, with a transition temperature of 19.3 K.  Improvements have since resulted in the preparation of 100% bulk superconductors 3.  Because of the absence of impurity phases, we have been able to perform accurate Rietveld analysis of X-ray diffraction data from the superconducting phase.  Here we report our results for the crystal structure of K3C60, determining that this superconducting compound has a face-centred cubic structure with a well defined stoichiometry.  These results should open the way to rigorous description of the normal and superconducting properties of this compound.
C1 UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024.
   SUNY BUFFALO,NEW YORK STATE INST SUPERCONDUCT,BUFFALO,NY 14214.
   SUNY BUFFALO,DEPT CHEM,BUFFALO,NY 14214.
   UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024.
   UNIV CALIF LOS ANGELES,CTR SOLID STATE SCI,LOS ANGELES,CA 90024.
C3 University of California System; University of California Los Angeles; State University of New York (SUNY) System; University at Buffalo, SUNY; State University of New York (SUNY) System; University at Buffalo, SUNY; University of California System; University of California Los Angeles; University of California System; University of California Los Angeles
RP STEPHENS, PW (corresponding author), SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794, USA.
NR 11
TC 721
Z9 742
U1 1
U2 136
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 632
EP 634
DI 10.1038/351632a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200057
DA 2026-03-10
ER

PT J
AU PODSIADLOWSKI, P
   FABIAN, AC
   STEVENS, IR
AF PODSIADLOWSKI, P
   FABIAN, AC
   STEVENS, IR
TI ORIGIN OF THE NAPOLEON HAT NEBULA AROUND SN1987A AND IMPLICATIONS FOR THE PROGENITOR
SO NATURE
LA English
DT Article
ID sn-1987a; winds; model
AB THE emission nebula around supernova 1987 A 1,2 is recombination radiation excited by the ultraviolet flash from the supernova explosion as it travels through circumstellar material. Recent observations show it to have a complex but clearly structured morphology, which has been likened to Napoleon's hat 1. We present here a simple geometrical model for the nebula, consisting of a ring and a truncated double cone. When the effects of light travel-time are included, the model reproduces the important topological structures of the nebula and makes detailed quantitative predictions for its future appearance. In particular, the hat-shaped northern rim is simply explained as the interaction of the light front with the northern cone. To explain the origin of the double cone, we argue that the progenitor of SN1987A was in a binary system: its strong wind, colliding with a weaker wind from the companion star, created an asymptotic shock surface that was spread out into the required geometry by the rotation of the binary. This suggestion is consistent with other binary models 13 for the progenitor of this unusual supernova.
RP PODSIADLOWSKI, P (corresponding author), UNIV CAMBRIDGE,INST ASTRON,MADINGLEY RD,CAMBRIDGE CB3 0HA,ENGLAND.
NR 18
TC 36
Z9 37
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 43
EP 46
DI 10.1038/354043a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900050
DA 2026-03-10
ER

PT J
AU TAYLOR, AR
   GREGORY, PC
   DURIC, N
   TSUTSUMI, T
AF TAYLOR, AR
   GREGORY, PC
   DURIC, N
   TSUTSUMI, T
TI GT2318 + 620, A VARIABLE GALACTIC SOURCE WITH A RADIO JET
SO NATURE
LA English
DT Article
ID x-ray sources; catalog
AB A RECENT galactic survey with the National Radio Astronomy Observatory (NRAO) 91-m telescope revealed a small number of variable radio sources at low galactic latitude 1.  Similar sources within the Galaxy, where they have been identified, are often associated with energetic objects such as X-ray binaries, pulsars, cataclysmic variables and flare stars.  One of the new variable sources, GT2318 + 620, is within the error box for the Uhuru X-ray source 4U2316 + 61 (ref. 2), and our measurement of the neutral hydrogen absorption towards GT2318 + 620, reported here, indicates that it is a galactic object, at a distance of 3-6 kpc.  We also present a high-resolution radio image of the source, which reveals an unresolved core with a jet-like feature extending on either side.  GT2318 + 620 is coincident with a star of approximately 20th magnitude, and we suggest here that it is radio-emitting low-mass X-ray binary.  The radio luminosity of GT2318 + 620 is markedly higher than that of Sco X-1, the only other low-mass X-ray binary to show a radio jet; in its radio brightness it resembles SS433, which is remarkable for its relativistic jet motion on arcsecond scales, thought to result from accretion onto a collapsed stellar object 3.
C1 UNIV BRITISH COLUMBIA,DEPT PHYS,VANCOUVER V6T 1W5,BC,CANADA.
   UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131.
C3 University of British Columbia; University of New Mexico
RP TAYLOR, AR (corresponding author), UNIV CALGARY,DEPT PHYS & ASTRON,2500 UNIV DR NW,CALGARY T2N 1N4,ALBERTA,CANADA.
NR 12
TC 6
Z9 6
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 547
EP 549
DI 10.1038/351547a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400050
DA 2026-03-10
ER

PT J
AU HEMPSTEAD, BL
   MARTINZANCA, D
   KAPLAN, DR
   PARADA, LF
   CHAO, MV
AF HEMPSTEAD, BL
   MARTINZANCA, D
   KAPLAN, DR
   PARADA, LF
   CHAO, MV
TI HIGH-AFFINITY NGF BINDING REQUIRES COEXPRESSION OF THE TRK PROTOONCOGENE AND THE LOW-AFFINITY NGF RECEPTOR
SO NATURE
LA English
DT Article
ID nerve growth-factor; pc12 pheochromocytoma cells; human neuro-blastoma; human-melanoma cells; neurotrophic factor; rat pheochromocytoma; molecular-cloning; gene-transfer; expression; brain
AB Nerve growth factor (NGF) interacts with two different low-affinity receptors that can be distinguished by affinity crosslinking. Reconstitution experiments by membrane fusion and transient transfection into heterologous cells indicate that high-affinity NGF binding requires coexpression and binding to both the low-affinity NGF receptor and the tyrosine kinase trk gene product. These studies reveal a new growth factor receptor-mediated mechanism of cellular differentiation involving trk and the low-affinity NGF receptor.
C1 NCI, FREDERICK CANC RES & DEV CTR, MOLEC EMBRYOL GRP, FREDERICK, MD 21701 USA.
   NCI, FREDERICK CANC RES & DEV CTR, ABL BASIC RES PROGRAM, FREDERICK, MD 21701 USA.
C3 National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Science Applications International Corporation (SAIC); SAIC-Frederick; Science Applications International Corporation (SAIC); SAIC-Frederick; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI)
RP HEMPSTEAD, BL (corresponding author), CORNELL UNIV, MED CTR,COLL MED,DEPT MED,DEPT CELL BIOL & ANAT, DIV HEMATOL ONCOL, 1300 YORK AVE, NEW YORK, NY 10021 USA.
NR 79
TC 1154
Z9 1264
U1 0
U2 17
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 678
EP 683
DI 10.1038/350678a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000050
PM 1850821
DA 2026-03-10
ER

PT J
AU GUO, XD
   JOHNSON, JJ
   KRAMER, JM
AF GUO, XD
   JOHNSON, JJ
   KRAMER, JM
TI EMBRYONIC LETHALITY CAUSED BY MUTATIONS IN BASEMENT-MEMBRANE COLLAGEN OF C-ELEGANS
SO NATURE
LA English
DT Article
ID caenorhabditis-elegans; iv collagen; dna; sequence; region; domain; genes; chain
AB BASEMENT membranes are specialized forms of extracellular matrix with important functions in development 1-3.  A major structural component of basement membranes is type IV collagen, a heterotrimer of two alpha-1(IV) and one alpha-2(IV) chains, which forms a complex, polygonal network associated with other basement membrane components 4,5.  Here we report that the alpha-1(IV) collagen chain of Caenorhabditis elegans is encoded by the genetic locus emb-9.  Mutations in emb-9 cause temperature-sensitive lethality during late embryogenesis.  We have identified single nucleotide alterations that substitute glutamic acid for glycine in the triple-helical Gly-X-Y repeat region of the alpha-1(IV) collagen in three emb-9 mutant strains.  These results are direct evidence that defects in basement membranes can disrupt embryonic development and form a basis for the genetic analysis of basement membrane function.
C1 UNIV ILLINOIS,DEPT BIOL SCI,MOLEC BIOL LAB,POB 4348,CHICAGO,IL 60680.
C3 University of Illinois System; University of Illinois Chicago; University of Illinois Chicago Hospital
NR 27
TC 92
Z9 113
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 707
EP 709
DI 10.1038/349707a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700051
PM 1996137
DA 2026-03-10
ER

PT J
AU CHOI, HK
   TONG, L
   MINOR, W
   DUMAS, P
   BOEGE, U
   ROSSMANN, MG
   WENGLER, G
AF CHOI, HK
   TONG, L
   MINOR, W
   DUMAS, P
   BOEGE, U
   ROSSMANN, MG
   WENGLER, G
TI STRUCTURE OF SINDBIS VIRUS CORE PROTEIN REVEALS A CHYMOTRYPSIN-LIKE SERINE PROTEINASE AND THE ORGANIZATION OF THE VIRION
SO NATURE
LA English
DT Article
ID semliki forest virus; alpha-lytic protease; amino-acid-sequence; capsid protein; rna virus; nonstructural proteins; cysteine proteases; mosaic-virus; resolution; alphavirus
AB Sindbis virus consists of a nucleocapsid core surrounded by a lipid membrane through which penetrate 80 glycoprotein trimers. The structure of the core protein comprising the coat surrounding the genomic RNA has been determined. The polypeptide fold from residue 114 to residue 264 is homologous to that of chymotrypsin-like serine proteinases with catalytic residues His 141, Asp 163 and Ser 215 of the core protein positioned as in other serine proteinases. The C-terminal tryptophan remains in the P1 substrate site subsequent to the autocatalytic cis cleavage of the capsid protein, thus rendering the proteinase inactive. Model building of the Sindbis core protein dimer shows that the nucleocapsid is likely to have T = 4 quasisymmetry.
C1 PURDUE UNIV, DEPT BIOL SCI, W LAFAYETTE, IN 47907 USA.
   UNIV ALBERTA, DEPT BIOCHEM, EDMONTON T6G 2H7, ALBERTA, CANADA.
   UNIV GIESSEN, INST VIROL, W-6300 GIESSEN, GERMANY.
C3 Purdue University System; Purdue University; University of Alberta; Justus Liebig University Giessen
NR 68
TC 275
Z9 316
U1 0
U2 11
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 37
EP 43
DI 10.1038/354037a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900049
PM 1944569
DA 2026-03-10
ER

PT J
AU RUDOLPH, AS
   RATNA, BR
   KAHN, B
AF RUDOLPH, AS
   RATNA, BR
   KAHN, B
TI SELF-ASSEMBLING PHOSPHOLIPID FILAMENTS
SO NATURE
LA English
DT Article
ID membranes; fluctuations; shapes
AB AQUEOUS dispersions of double-chain phospholipids spontaneously assemble into closed bilayers called vesicles (or liposomes). Although the vesicles are in general topologically spherical, cylindrical 1 and helical 2 liposomes have sometimes been observed. We present here video-enhanced microscopic studies of a diacetylenic phospholipid dispersed in ethanol/water, which reveal the existence of unusual bilayer morphologies. On cooling the dispersion from the isotropic phase, we have observed the formation of long (of the order of hundreds of micrometres), thin (0.2-2-mu-m) filaments, which fluctuate strongly. When the temperature is decreased further, the filaments rapidly retract into a mass of lipid. At constant temperature, on the other hand, the filaments transform into torus or ring-like vesicles. Such nonspherical structures have been predicted theoretically 3,4 but not previously observed experimentally.
C1 GEORGETOWN UNIV,MED CTR,DEPT BIOCHEM,WASHINGTON,DC 20007.
   GEOCENTERS INC,FT WASHINGTON,MD 20744.
C3 Georgetown University; Geo-Centers Inc.
RP RUDOLPH, AS (corresponding author), USN,RES LAB,CTR BIOMOLEC SCI & ENGN,CODE 6090,WASHINGTON,DC 20375, USA.
NR 16
TC 43
Z9 45
U1 0
U2 17
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 52
EP 55
DI 10.1038/352052a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800066
PM 2062377
DA 2026-03-10
ER

PT J
AU MORAN, N
AF MORAN, N
TI PRESCRIPTIONS FOR PHARMACEUTICAL RESEARCH
SO NATURE
LA English
DT Article
NR 0
TC 1
Z9 1
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 873
EP 874
DI 10.1038/353873a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200071
DA 2026-03-10
ER

PT J
AU FOUQUET, Y
   VONSTACKELBERG, U
   CHARLOU, JL
   DONVAL, JP
   ERZINGER, J
   FOUCHER, JP
   HERZIG, P
   MUHE, R
   SOAKAI, S
   WIEDICKE, M
   WHITECHURCH, H
AF FOUQUET, Y
   VONSTACKELBERG, U
   CHARLOU, JL
   DONVAL, JP
   ERZINGER, J
   FOUCHER, JP
   HERZIG, P
   MUHE, R
   SOAKAI, S
   WIEDICKE, M
   WHITECHURCH, H
TI HYDROTHERMAL ACTIVITY AND METALLOGENESIS IN THE LAU BACK-ARC BASIN
SO NATURE
LA English
DT Article
ID east pacific rise; chemistry; ridge
AB IN 1989, the submersible Nautile discovered one of the most active hydrothermal fields on the modern ocean floor, in the Lau back-arc basin (Fig. 1).  The field contains high-temperature white and black smokers, and as we report here, its characteristics contrast strongly with those of the hydrothermal fields found at normal mid-ocean ridges.  The main differences are the acidity (pH as low as 2), chemistry and temperature (up to 400-degrees-C) of the hydrothermal fluids, the composition of the ore deposits, and the volcanic and tectonic environments.  The fluids also have very high concentrations of trace metals, and primary gold is present in the accompanying mineral deposits.  Our data show that these back-arc deposits in the Lau Basin are intermediate between typical mid-ocean-ridge mineralization and massive sulphide deposits of the Kuroko type.
C1 BUNDESANSTALT GEWISSENSCH & ROHSTOFFE,W-3000 HANNOVER 51,GERMANY.
   UNIV GIESSEN,INST GEOWISSENSCH,W-6300 GIESSEN,GERMANY.
   RHEIN WESTFAL TH AACHEN,INST MINERAL & LAGERSTATTENLEHRE,W-5100 AACHEN,GERMANY.
   MINIST LANDS SURVEY & NAT RESOURCES,NUKUALOFA,TONGA.
   ECOLE & OBSERV PHYS GLOBE STRASBOURG,F-67084 STRASBOURG,FRANCE.
   UNIV KIEL,INST GEOL,W-2300 KIEL 1,GERMANY.
C3 Justus Liebig University Giessen; RWTH Aachen University; University of Kiel
RP FOUQUET, Y (corresponding author), IFREMER,CTR BREST,BP 70,F-29280 PLOUZANE,FRANCE.
NR 19
TC 164
Z9 181
U1 2
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 778
EP 781
DI 10.1038/349778a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600051
DA 2026-03-10
ER

PT J
AU BORNER, C
   FILIPUZZI, I
   WEINSTEIN, IB
   IMBER, R
AF BORNER, C
   FILIPUZZI, I
   WEINSTEIN, IB
   IMBER, R
TI FAILURE OF WILD-TYPE OR A MUTANT FORM OF PROTEIN KINASE-C-ALPHA TO TRANSFORM FIBROBLASTS
SO NATURE
LA English
DT Article
ID ras oncogene; cells; growth
AB A MUTANT form of the alpha-isoform of protein kinase C (PKC) was recently isolated from an ultraviolet radiation-induced murine fibrosarcoma cell line and reported to transform mouse BALB/c 3T3 fibroblasts on transfection 1.  Four point mutations in the regulatory domain were assumed to be responsible for its oncogenicity and unusual preference for membrane localization. Here, we report that overexpression of the reported mutant PKC-alpha complementary DNA in three fibroblast cell lines, including BALB/c 3T3, does not enable these cells to grow in soft agar or nude mice. In addition, this mutant PKC-alpha form seems to be indistinguishable from the wild-type PKC-alpha with respect to its dependence on cofactors, phorbol ester binding, subcellular distribution and its effects on growth and morphology. These results fail to confirm the previous study 1 and indicate that overexpression of either the wild-type or the reported mutant form of PKC-alpha does not transform rodent fibroblasts.
C1 COLUMBIA UNIV,CTR COMPREHENS CANC,NEW YORK,NY 10032.
   COLUMBIA UNIV,INST CANC RES,NEW YORK,NY 10032.
   UNIV BASEL CLIN,SCH MED,MOLEC TUMORBIOL LAB,CH-4031 BASEL,SWITZERLAND.
C3 Columbia University; Columbia University; University of Basel
NR 12
TC 82
Z9 83
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 78
EP 80
DI 10.1038/353078a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500063
PM 1881450
DA 2026-03-10
ER

PT J
AU PUTKONEN, P
   THORSTENSSON, R
   GHAVAMZADEH, L
   ALBERT, J
   HILD, K
   BIBERFELD, G
   NORRBY, E
AF PUTKONEN, P
   THORSTENSSON, R
   GHAVAMZADEH, L
   ALBERT, J
   HILD, K
   BIBERFELD, G
   NORRBY, E
TI PREVENTION OF HIV-2 AND SIVSM INFECTION BY PASSIVE-IMMUNIZATION IN CYNOMOLGUS MONKEYS
SO NATURE
LA English
DT Article
ID macaca-fascicularis; immunodeficiency; virus; glycoprotein; protection; chimpanzees; macaques; leukemia; gp71
AB INFECTION of macaques with simian immunodeficiency virus (SIV) 1,2 and human immunodeficiency virus type 2 (HIV-2) 3,4 are useful models for studies of immunotherapy and vaccination against HIV as well as for testing of antiviral drugs. Vaccine research showing protective immunity in immunized monkeys 4-10 has indicated that it will be possible to develop a vaccine for prevention of human HIV infection, although many hurdles remain. The design of an HIV vaccine would be helped if the basis of the protective immunity could be elucidated. Passive immune prophylaxis offers a means to determine the relative role of antibodies in protection against infection. We have studied whether a transfer of antibodies can prevent HIV-2 and SIV(sm) (SIV of sooty mangabey origin) infection in cynomolgus monkeys. Sera with high antibody titres were collected, heat-treated and injected into naive animals 6 h before challenge with 10-100 monkey-infectious doses of live homologous virus. All control animals treated with normal monkey serum (n = 6) or no serum (n = 39) became infected by the challenge virus, whereas five out of seven animals pretreated with antibody-containing serum at a dose of 9 ml kg-1 resisted infection. Thus passively transferred antibodies can protect against a low-dose lentivirus challenge in a nonhuman primate.
C1 NATL BACTERIOL LAB,DEPT VIROL,S-10521 STOCKHOLM,SWEDEN.
   KAROLINSKA INST,DEPT VIROL,S-10521 STOCKHOLM,SWEDEN.
C3 Karolinska Institutet
RP PUTKONEN, P (corresponding author), NATL BACTERIOL LAB,DEPT IMMUNOL,S-10521 STOCKHOLM,SWEDEN.
NR 20
TC 203
Z9 217
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 436
EP 438
DI 10.1038/352436a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600067
PM 1677743
DA 2026-03-10
ER

PT J
AU PYLE, AM
   CECH, TR
AF PYLE, AM
   CECH, TR
TI RIBOZYME RECOGNITION OF RNA BY TERTIARY INTERACTIONS WITH SPECIFIC RIBOSE 2'-OH GROUPS
SO NATURE
LA English
DT Article
ID tetrahymena ribozyme; intervening sequence; kinetics; binding; temperature; substrate; selection
AB SHORTENED forms of the group I intron from Tetrahymena catalyse sequence-specific cleavage of exogenous oligonucleotide substrates 1, 2.  The association between RNA enzyme (ribozyme) and substrate is mediated by pairing between an internal guide sequence on the ribozyme and a complementary sequence on the substrate 1, 3, 4.  RNA substrates and cleavage products associate with a binding energy greater than that of base-pairing by approximately 4 kcal-mol-1 (at 42-degrees-C), whereas DNA associates with an energy around that expected for base-pairing 5-9.  It has been proposed that the difference in binding affinity is due to specific 2'-OH groups on an RNA substrate forming stabilizing tertiary interactions with the core of the ribozxyme, or that the RNA.RNA helix formed upon association of an RNA substrate and the ribozyme might be more stable than an RNA.DNA helix of the same sequence 6.  To differentiate between these two models, chimaeric oligonucleotides containing deoxynucleotide residues at successive positions along the chain were synthesized, and their equilibrium binding constants for association with the ribozyme were measured directly by a new gel electrophoresis technique 5.  We report here that most of the extra binding energy can be accounted for by discrete RNA-ribozyme interactions, the 2'-OH group on the sugar residue three nucleotides from the cleavage site contributing the most interaction energy.  Thus, in addition to the well documented binding of RNA to RNA by base-pairing 10-14, 2'-OH groups within a duplex can also mediate association between RNA molecules.
C1 UNIV COLORADO,HOWARD HUGHES MED INST,BOULDER,CO 80309.
   UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309.
C3 Howard Hughes Medical Institute; University of Colorado System; University of Colorado Boulder; University of Colorado System; University of Colorado Boulder
NR 31
TC 188
Z9 200
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 628
EP 631
DI 10.1038/350628a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200066
PM 1708111
DA 2026-03-10
ER

PT J
AU MURPHY, BW
   RUTTEN, RGM
   CALLANAN, PJ
   SEITZER, P
   CHARLES, PA
   COHN, HN
   LUGGER, PM
AF MURPHY, BW
   RUTTEN, RGM
   CALLANAN, PJ
   SEITZER, P
   CHARLES, PA
   COHN, HN
   LUGGER, PM
TI DETECTION OF BINARIES IN THE CORE OF THE GLOBULAR-CLUSTER M15 USING CALCIUM EMISSION-LINES
SO NATURE
LA English
DT Article
ID fk comae; stars; atmospheres; evolution
AB M15 is the prototypical collapsed-core globular cluster.  Having undergone collapse, its core is believed now to be expanding, with energy for the re-expansion provided by binary stars, which turn gravitational potential energy into kinetic energy 1.  Because these binary stars are generally more massive than single stars, they will have settled to the centre of the cluster 2.  We report here that several of the stars at the core of M15 show Ca II H- and K-line emission, characteristic of young, rapidly rotating stars and close binaries 3.  We argue that the emission from M15 comes from primordial binaries, in which a period of spin-up has led to magnetic field generation by enhanced dynamo action, which in turn causes heating of the stellar chromospheres.  If this interpretation is correct, the Ca H and K emission may provide an important diagnostic tool of the binary population in cluster cores, and thus of the cluster dynamics.
C1 ASTRON INST ANTON PANNEKOEK,1098 SJ AMSTERDAM,NETHERLANDS.
   UNIV OXFORD,DEPT ASTROPHYS,OXFORD OX1 3R4,ENGLAND.
   SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218.
   OBSERV ROQUE MUCHACHOS,TENERIFE,SPAIN.
   INDIANA UNIV,DEPT ASTRON,BLOOMINGTON,IN 47405.
C3 University of Amsterdam; University of Oxford; Space Telescope Science Institute; Indiana University System; Indiana University Bloomington
RP MURPHY, BW (corresponding author), STATE UNIV UTRECHT,INST ASTRON,POSTBUS 80000,3508 TA UTRECHT,NETHERLANDS.
NR 22
TC 12
Z9 12
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 130
EP 132
DI 10.1038/351130a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500043
DA 2026-03-10
ER

PT J
AU RAMSKOLD, L
   HOU, XG
AF RAMSKOLD, L
   HOU, XG
TI NEW EARLY CAMBRIAN ANIMAL AND ONYCHOPHORAN AFFINITIES OF ENIGMATIC METAZOANS
SO NATURE
LA English
DT Article
AB THERE is much interest in the early evolution of metazoans with the restudy of the Middle Cambrian 'soft-bodied' fauna of the Burgess Shale 1. Several other, newly discovered Cambrian 'soft-bodied' faunas 2 provide a wealth of new data. One of the oldest and best-preserved faunas was discovered in 1984 in Chengjiang in southern China 3. This fauna is of early Cambrian age, about late Atdabanian 4 (approximately 520-530 Myr BP)2. We now describe a new 'armoured lobopod' from the Chengjiang fauna. This animal shows close affinity with the enigmatic Microdictyon 5. The conundrum Hallucigenia 6 is reinterpreted as another 'armoured lobopod', as are Xenusion 7 and Luolishania 8. The large plates set in pairs along the trunk are a synapomorphy of this group, which flourished soon after the 'Cambrian explosion'. Soft-part anatomy suggests that the group has affinities with the Burgess Shale 'lobopod' Aysheaia 9. All these marine, Cambrian forms are here grouped with the extant, terrestrial velvet worms in the phylum Onychophora.
C1 ACAD SINICA, NANJING INST GEOL & PALAEONTOL, NANJING, PEOPLES R CHINA.
C3 Chinese Academy of Sciences
RP RAMSKOLD, L (corresponding author), SWEDISH MUSEUM NAT HIST, DEPT PALAEOZOOL, BOX 50007, S-10405 STOCKHOLM, SWEDEN.
NR 32
TC 92
Z9 102
U1 0
U2 26
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 225
EP 227
DI 10.1038/351225a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000054
DA 2026-03-10
ER

PT J
AU FRANK, D
   KESHET, I
   SHANI, M
   LEVINE, A
   RAZIN, A
   CEDAR, H
AF FRANK, D
   KESHET, I
   SHANI, M
   LEVINE, A
   RAZIN, A
   CEDAR, H
TI DEMETHYLATION OF CPG ISLANDS IN EMBRYONIC-CELLS
SO NATURE
LA English
DT Article
ID x-chromosome inactivation; denovo methylation; dna methylation; chromatin structure; transgenic mice; 2 genes; mouse; expression; embryogenesis; lines
AB DNA in differentiated somatic cells has a fixed pattern of methylation, which is faithfully copied after replication. By contrast, the methylation patterns of many tissue-specific and some housekeeping genes are altered during normal development 1. This modification of DNA methylation in the embryo has also been observed in transgenic mice and in transfection experiments 2. Here we report the fate in mice of an in vitro-methylated adenine phosphoribosyltransferase transgene. The entire 5' CpG island region became demethylated, whereas the 3' end of the gene remained modified and was even methylated de novo at additional sites. Transfection experiments in vitro show that the demethylation is rapid, is specific for embryonic cell-types and affects a variety of different CpG island sequences. This suggests that gene sequences can be recognized in the early embryo and imprinted with the correct methylation pattern through a combination of demethylation and de novo methylation.
C1 AGR RES ORG, VOLCANI CTR, INST ANIM SCI, IL-50250 BET DAGAN, ISRAEL.
C3 Volcani Institute of Agricultural Research
RP FRANK, D (corresponding author), HEBREW UNIV JERUSALEM, SCH MED, DEPT CELLULAR BIOCHEM, POB 1172, JERUSALEM, ISRAEL.
NR 27
TC 134
Z9 142
U1 0
U2 5
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 239
EP 241
DI 10.1038/351239a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000059
PM 2041571
DA 2026-03-10
ER

PT J
AU SCHOUTEN, PG
   WARMAN, JM
   DEHAAS, MP
   FOX, MA
   PAN, HL
AF SCHOUTEN, PG
   WARMAN, JM
   DEHAAS, MP
   FOX, MA
   PAN, HL
TI CHARGE MIGRATION IN SUPRAMOLECULAR STACKS OF PERIPHERALLY SUBSTITUTED PORPHYRINS
SO NATURE
LA English
DT Article
ID electron
AB PORPHYRIN derivatives play a central part in energy- and electron-transfer processes in natural systems, in which they occur as individual entities or, commonly, as oligomers or supramolecular assemblies. These compounds have also been proposed for use in conducting and photoconducting bulk materials and as conductive and capacitive elements in molecular electronic devices. Much effort has therefore been devoted towards understanding the factors that control energy and charge transport within porphyrin assemblies. Here we describe studies of charge migration along one-dimensional columnar stacks-of porphyrin molecules bearing peripheral hydrocarbon groups. In both the solid phase and the relatively plastic liquid-crystalline mesophase, in which the hydrocarbon groups are mobile, charge is transferred between adjacent porphyrin groups with a jump time of a few picoseconds or less. The isotropic liquid phase, on the other hand, is not conductive. The formation of supramolecular structures therefore seems to be necessary to support and direct charge and energy migration in these systems.
C1 UNIV TEXAS,DEPT CHEM,AUSTIN,TX 78712.
C3 University of Texas System; University of Texas Austin
RP SCHOUTEN, PG (corresponding author), DELFT UNIV TECHNOL,IRI,MEKELWEG 15,2629 JB DELFT,NETHERLANDS.
NR 13
TC 240
Z9 248
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 736
EP 737
DI 10.1038/353736a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600061
DA 2026-03-10
ER

PT J
AU WANG, J
   BEDZYK, MJ
   PENNER, TL
   CAFFREY, M
AF WANG, J
   BEDZYK, MJ
   PENNER, TL
   CAFFREY, M
TI STRUCTURAL STUDIES OF MEMBRANES AND SURFACE-LAYERS UP TO 1,000 A THICK USING X-RAY STANDING WAVES
SO NATURE
LA English
DT Article
ID bragg-diffraction; interface; reflection; fields
AB THE X-ray standing wave (XSW) method, developed in the 1960s, was used originally to determine heavy atom positions in and on silicon and germanium single crystals 1-7. An X-ray standing wave generated by the interference of coherent incident and reflected beams excites X-ray fluorescence from the heavy atom, the intensity of which as a function of incident angle provides an indication of the atom's distance from the X-ray reflecting surface. The availability of X-ray mirrors and the ability to prepare layered synthetic microstructures has made possible the study of biologically relevant structures using the XSW technique on length scales of typically tens to hundreds of angstroms 8-12, allowing heavy atoms in such structures to be located with angstrom or subangstrom resolution. Many model biological systems (such as Langmuir-Blodgett films, which mimic membranes) require access to still larger scales, but it is not obvious that an XSW will remain coherent over such length scales. Here we report studies of a lipid multilayer system using the XSW method, in which we have been able to locate the metal atoms in a zinc arachidate bilayer with angstrom resolution at a distance of almost 1,000 angstrom above the surface of a gold mirror. Our results indicate that the XSW technique should be useful for structural studies of supramolecular aggregates, receptor-ligand interactions and multi-membrane stacks, in which length scales of this order are encountered.
C1 CORNELL UNIV,CORNELL HIGH ENERGY SYNCHROTRON SOURCE,ITHACA,NY 14853.
   EASTMAN DENT CTR,CORP RES LABS,ROCHESTER,NY 14620.
C3 Cornell University; University of Rochester; Eastman Chemical Company
RP WANG, J (corresponding author), OHIO STATE UNIV,DEPT CHEM,COLUMBUS,OH 43210, USA.
NR 17
TC 63
Z9 68
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 377
EP 380
DI 10.1038/354377a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100045
PM 1956399
DA 2026-03-10
ER

PT J
AU JAP, BK
   WALIAN, PJ
   GEHRING, K
AF JAP, BK
   WALIAN, PJ
   GEHRING, K
TI STRUCTURAL ARCHITECTURE OF AN OUTER-MEMBRANE CHANNEL AS DETERMINED BY ELECTRON CRYSTALLOGRAPHY
SO NATURE
LA English
DT Article
ID escherichia-coli; rhodobacter-capsulatus; sensitive specimens; lipid bilayers; phoe protein; porin; resolution; beam
AB PORINS are a family of membrane channels commonly found in the outer membranes of Gram-negative bacteria where they serve as diffusional pathways for waste products, nutrients and antibiotics,  and can also be receptors for bacteriophages 1,2.  Porin channels have been shown in vitro to be voltage-gated 3-6.  They can exhibit slight selectivities for certain solutes; for example PhoE porin has some selectivity for anionic and phosphate-containing compounds 1,7.  Unlike many known membrane proteins which often contain long stretches of hydrophobic segments that are believed to traverse the membrane in a helical conformation, porins are found to have charged residues distributed almost uniformly along their primary sequences and have most of their secondary structure in a beta-sheet conformation 8-10.  We have made crystalline patches of PhoE porin embedded in a lipid bilayer and have used these to determine the structure of PhoE porin by electron crystallography to a resolution of 6 angstrom.  The basic structure consists of a trimer of elliptically shaped, cylindrical walls of beta-sheet.  Each cylinder has an inner lining, formed by parts of the polypeptide, that defines the channel size.  The structure provides a clue as to how deletions of segments of polypeptide, which are found in certain mutants, can result in an actual increase in the channel size.
RP JAP, BK (corresponding author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DONNER LAB,BERKELEY,CA 94720, USA.
NR 26
TC 132
Z9 137
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 167
EP 170
DI 10.1038/350167a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500064
PM 1848682
DA 2026-03-10
ER

PT J
AU CHAVRIER, P
   GORVEL, JP
   STELZER, E
   SIMONS, K
   GRUENBERG, J
   ZERIAL, M
AF CHAVRIER, P
   GORVEL, JP
   STELZER, E
   SIMONS, K
   GRUENBERG, J
   ZERIAL, M
TI HYPERVARIABLE C-TERMINAL DOMAIN OF RAB PROTEINS ACTS AS A TARGETING SIGNAL
SO NATURE
LA English
DT Article
ID gtp-binding-proteins; molecular-cloning; cell-line; secretion; transferrin; family; cdnas; brain; genes; virus
AB MAMMALIAN cells express many ras-like low molecular mass GTP-binding proteins (rab proteins) 1-6 that are highly homologous to the Ypt1 and Sec4 proteins involved in controlling secretion in yeast 7-9. Owing to their structural similarity and to their variety, rab proteins have been postulated to act as specific regulators of membrane traffic in exocytosis and endocytosis 10, and rab5 has been shown to be involved in early endosome fusion in vitro 11. In agreement with their postulated functions, all rab proteins studied so far have been found in distinct subcompartments along the exocytic or endocytic pathways 5,11-13. To define the region mediating their specific localization, we transiently expressed rab2, rab5 and rab7 hybrid proteins in BHK cells, and determined their intracellular localization by immunofluorescence confocal microscopy and subcellular fractionation. Here we present evidence that the highly variable C-terminal domain contains structural elements necessary for the association of rab proteins with their specific target membranes in the endocytic pathway.
C1 EUROPEAN MOLEC BIOL LAB, POSTFACH 102209, W-6900 HEIDELBERG, GERMANY.
C3 European Molecular Biology Laboratory (EMBL)
NR 25
TC 349
Z9 404
U1 0
U2 18
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 769
EP 772
DI 10.1038/353769a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600073
PM 1944536
DA 2026-03-10
ER

PT J
AU GLOTZER, M
   MURRAY, AW
   KIRSCHNER, MW
AF GLOTZER, M
   MURRAY, AW
   KIRSCHNER, MW
TI CYCLIN IS DEGRADED BY THE UBIQUITIN PATHWAY
SO NATURE
LA English
DT Article
ID recognition particle srp; embryonic-cell cycle; short-lived protein; sea-urchin eggs; messenger-rna; phytochrome degradation; biochemical-mutants; proteolytic system; conjugating enzyme; activating enzyme
AB Cyclin degradation is the key step governing exit from mitosis and progress into the next cell cycle.  When a region in the N terminus of cyclin is fused to a foreign protein, it produces a hybrid protein susceptible to proteolysis at mitosis.  During the course of degradation, both cyclin and the hybrid form conjugates with ubiquitin. The kinetic properties of the conjugates indicate that cyclin is degraded by ubiquitin-dependent proteolysis.  Thus anaphase may be triggered by the recognition of cyclin by the ubiquitin-conjugating system.
C1 UNIV CALIF SAN FRANCISCO,SCH MED,DEPT PHYSIOL,SAN FRANCISCO,CA 94143.
C3 University of California System; University of California San Francisco
RP GLOTZER, M (corresponding author), UNIV CALIF SAN FRANCISCO,SCH MED,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143, USA.
NR 49
TC 2142
Z9 2476
U1 1
U2 130
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 132
EP 138
DI 10.1038/349132a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800049
PM 1846030
DA 2026-03-10
ER

PT J
AU GOLDFARB, RJ
   SNEE, LW
   MILLER, LD
   NEWBERRY, RJ
AF GOLDFARB, RJ
   SNEE, LW
   MILLER, LD
   NEWBERRY, RJ
TI RAPID DEWATERING OF THE CRUST DEDUCED FROM AGES OF MESOTHERMAL GOLD DEPOSITS
SO NATURE
LA English
DT Article
ID coast plutonic complex; british-columbia; regional metamorphism; southeastern alaska; history; evolution; belt
AB THE large-scale migration of fluids through the continental crust has been well documented, but there is no consensus regarding the timing of fluid migration relative to orogenic episodes, or rates of crustal dewatering 1. Here we present 40Ar/39Ar dates for muscovites from quartz veins along a major shear zone in southeast Alaska, which show that the veins were emplaced in the early Eocene, during the late stages of orogenic deformation. Hydrothermal activity took place for only about 1 Myr and along a distance of at least 200 km. The fluids were generated by metamorphic reactions in subducted crust along the North American plate margin, and were apparently trapped in the crust by the low permeabilities accompanying a convergent tectonic regime until 56 Myr ago. The rapid dewatering event coincided with a change in plate motion at 56-55 Myr, which caused a shift from convergent to partly transcurrent tectonics. We suggest that this change in tectonic regime led to increased crustal permeabilities and hence the possibility of large-scale fluid migration.
C1 ECHO BAY MINES, JUNEAU, AK 99801 USA.
   UNIV ALASKA, DEPT GEOL, FAIRBANKS, AK 99775 USA.
C3 University of Alaska System; University of Alaska Fairbanks
RP GOLDFARB, RJ (corresponding author), US GEOL SURVEY, DENVER FED CTR, BOX 25046, MS 973, DENVER, CO 80225 USA.
NR 30
TC 134
Z9 145
U1 0
U2 25
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 296
EP 298
DI 10.1038/354296a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400044
DA 2026-03-10
ER

PT J
AU RORSMAN, P
   BOKVIST, K
   AMMALA, C
   ARKHAMMAR, P
   BERGGREN, PO
   LARSSON, O
   WAHLANDER, K
AF RORSMAN, P
   BOKVIST, K
   AMMALA, C
   ARKHAMMAR, P
   BERGGREN, PO
   LARSSON, O
   WAHLANDER, K
TI ACTIVATION BY ADRENALINE OF A LOW-CONDUCTANCE G- PROTEIN-DEPENDENT K+ CHANNEL IN MOUSE PANCREATIC B-CELLS
SO NATURE
LA English
DT Article
ID insulin-secreting cells; free ca-2+ concentration; beta-cells; sulfonylureas; inhibition; galanin
AB INSULIN is produced and secreted by the B cells in the endocrine pancreas.  In vivo, insulin secretion is under the control of a number of metabolic, neural and hormonal substances.  It is now clear that stimulation of insulin release by fuel secretagogues, such as glucose, involves the closure of K+ channels that are sensitive ot the intracellular ATP concentration (K(ATP) channels)1.  This leads to membrane depolarization and the generation of Ca2+-dependent action potentials2.  The mechanisms whereby hormones and neurotransmitters such as adrenaline, galanin and somatostatin, which are released by intraislet nerve endings and the pancreatic D cells, produce inhibition of insulin secretion are not clear3.  Here we show that adrenaline suppresses B-cell electrical activity (and thus insulin secretion) by a G protein-dependent mechanism, which culminates in the activation of a sulphonylurea-insensitive low-conductance K+ channel distinct from the K(ATP) channel.
C1 KAROLINSKA INST,DEPT ENDOCRINOL,S-10401 STOCKHOLM 60,SWEDEN.
   KAROLINSKA INST,DEPT PHARMACOL,S-10401 STOCKHOLM 60,SWEDEN.
C3 Karolinska Institutet; Karolinska Institutet
RP RORSMAN, P (corresponding author), GOTHENBURG UNIV,DEPT MED PHYS,BOX 33031,S-40033 GOTHENBURG,SWEDEN.
NR 13
TC 125
Z9 134
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 77
EP 79
DI 10.1038/349077a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100056
PM 1898674
DA 2026-03-10
ER

PT J
AU MANGO, SE
   MAINE, EM
   KIMBLE, J
AF MANGO, SE
   MAINE, EM
   KIMBLE, J
TI CARBOXY-TERMINAL TRUNCATION ACTIVATES GLP-1 PROTEIN TO SPECIFY VULVAR FATES IN CAENORHABDITIS-ELEGANS
SO NATURE
LA English
DT Article
ID c-elegans; cell-interactions; growth-factor; lin-12 gene; mutations; nematode; drosophila; induction; stability; decision
AB THE glp-1 and lin-12 genes encode homologous transmembrane proteins 1,2 that may act as receptors for cell interactions during development 3,4.  The glp-1 product is required for induction of germ-line proliferation and for embryogenesis 3,5.  By contrast, lin-12 mediates somatic cell interactions, including those between the precursor cells that form the vulval hypodermis (VPCs) 6.  Here we analyse an unusual allele of glp-1, glp-1(q35), which displays a semidominant multivulva phenotype (Muv), as well as the typical recessive, loss-of-function Glp phenotypes (sterility and embryonic lethality) 3.  We find that the effects of glp-1(q35) on VPC development mimic those of dominant lin-12 mutations, even in the absence of lin-12 activity.  The glp-1(q35) gene bears a nonsense mutation predicted to eliminate the 122 C-terminal amino acids, including a ProGluSerThr (PEST) sequence thought to destabilize proteins.  We suggest that the carboxy terminus bears a negative regulatory domain which normally inactivates glp-1 in the VPCs.  We propose that inappropriate glp-1(q35) activity can substitute for lin-12 to determine vulval fate, perhaps by driving the VPCs to proliferate.
C1 UNIV WISCONSIN,MOLEC BIOL LAB,1525 LINDEN DR,MADISON,WI 53706.
   UNIV WISCONSIN,DEPT BIOCHEM,MADISON,WI 53706.
   SYRACUSE UNIV,DEPT BIOL,SYRACUSE,NY 13214.
C3 University of Wisconsin System; University of Wisconsin Madison; University of Wisconsin System; University of Wisconsin Madison; Syracuse University
NR 27
TC 61
Z9 89
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 811
EP 815
DI 10.1038/352811a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400063
PM 1881436
DA 2026-03-10
ER

PT J
AU SHANG, QY
   DOU, XM
   HUDSON, BS
AF SHANG, QY
   DOU, XM
   HUDSON, BS
TI OFF-AXIS ORIENTATION OF THE ELECTRONIC-TRANSITION MOMENT FOR A LINEAR CONJUGATED POLYENE
SO NATURE
LA English
DT Article
AB IN many applications of conjugated polyenes for nonlinear optoelectronics and as probes of biophysical systems, the orientation of the electronic transition dipole moment relative to the long axis of the chains is an important quantity. Simple models predict that the transition moment lies closely along the chain axis 1,2 or at an angle of about 30-degrees to this axis 3, but the difficulty of preparing perfectly oriented samples has made these predictions hard to test. Here we report the results of polarized single crystal spectroscopy of a linear conjugated tetraene in the highly aligned configuration made possible by incorporating these molecules as guests in the channels of urea crystals. The angular dependence of the absorption spectrum indicates that the transition moment lies at an angle of 15-degrees to the chain axis. Molecular-orbital calculations can reproduce this value when they include the effects of electron correlation.
C1 UNIV OREGON,DEPT CHEM,EUGENE,OR 97403.
   UNIV OREGON,INST CHEM PHYS,EUGENE,OR 97403.
C3 University of Oregon; University of Oregon
NR 40
TC 43
Z9 43
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 703
EP 705
DI 10.1038/352703a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400053
DA 2026-03-10
ER

PT J
AU DAVIDSEN, AF
   KRISS, GA
   FERGUSON, HC
   BLAIR, WP
   BOWERS, CW
   DIXON, WV
   DURRANCE, ST
   FELDMAN, PD
   HENRY, RC
   KIMBLE, RA
   KRUK, JW
   LONG, KS
   MOOS, HW
   VANCURA, O
AF DAVIDSEN, AF
   KRISS, GA
   FERGUSON, HC
   BLAIR, WP
   BOWERS, CW
   DIXON, WV
   DURRANCE, ST
   FELDMAN, PD
   HENRY, RC
   KIMBLE, RA
   KRUK, JW
   LONG, KS
   MOOS, HW
   VANCURA, O
TI TEST OF THE DECAYING DARK MATTER HYPOTHESIS USING THE HOPKINS ULTRAVIOLET TELESCOPE
SO NATURE
LA English
DT Article
ID rich clusters; galaxy; neutrinos; dust
AB SCIAMA has argued 1-4 that the dark matter associated with galaxies, clusters of galaxies and the intergalactic medium consists of tau-neutrinos of rest mass 28-30 eV, whose decay generates ultraviolet photons of energy approximately m-nu/2 almost-equal-to 14-15 eV.  We have carried out a test of this hypothesis using the Hopkins Ultraviolet Telescope, which was flown aboard the space shuttle Columbia as part of the Astro-1 mission in December 1990.  A straightforward application of Sciama's model predicts that we should have observed, from the rich galaxy cluster Abell 665, a spectral line from neutrino decay photons with a signal-to-noise ratio of approximately 30.  We detected no such emission.  For neutrinos (or any similar dark matter particle) in the mass range 27.2-32.1 eV, our observations set a lower lifetime limit significantly greater than Sciama's model requires.
RP DAVIDSEN, AF (corresponding author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,CTR ASTROPHYS SCI,34TH & CHARLES ST,BALTIMORE,MD 21218, USA.
NR 21
TC 48
Z9 49
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 128
EP 130
DI 10.1038/351128a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500042
DA 2026-03-10
ER

PT J
AU KROLIK, JH
AF KROLIK, JH
TI CREATION BY STELLAR ABLATION OF THE LOW-MASS COMPANION TO PULSAR 1829-10
SO NATURE
LA English
DT Article
ID eclipsing millisecond pulsar; binary; psr-1957+20; terzan-5
AB THE pulsar 1829 - 10 has a remarkable companion 1 of only approximately 10 Earth masses, which occupies a nearly circular orbit of 184-day period. Bailes et al. 1 speculate that this companion is a planet which has either survived the earlier stellar evolution and supernova which created the pulsar, or else formed through some sort of coagulation process during the lifetime of the pulsar. I argue here that another interpretation, which they excluded, may actually be more plausible: that the companion began its life as a star, and has been ablated down to its present mass by absorbing a portion of the pulsar's spindown energy. That similar phenomena have already been seen in two other binary pulsars, PSR 1957 + 20 (refs 2, 3) and PSR 1744 - 24A (refs 4, 5), lends preliminary credence to this suggestion. The (surprisingly small) final mass of the remnant is determined by the interplay between decreasing spindown luminosity, recession of the companion from the pulsar as a result of its mass loss, and, most importantly, shrinkage of the companion due to convective cooling of its interior.
RP KROLIK, JH (corresponding author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA.
NR 17
TC 13
Z9 14
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 829
EP 831
DI 10.1038/353829a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200053
DA 2026-03-10
ER

PT J
AU MELDRUM, FC
   WADE, VJ
   NIMMO, DL
   HEYWOOD, BR
   MANN, S
AF MELDRUM, FC
   WADE, VJ
   NIMMO, DL
   HEYWOOD, BR
   MANN, S
TI SYNTHESIS OF INORGANIC NANOPHASE MATERIALS IN SUPRAMOLECULAR PROTEIN CAGES
SO NATURE
LA English
DT Article
ID iron uptake; ferritin; crystallites; apoferritin; mechanism
AB THERE is currently great interest in the synthesis of inorganic materials of nanometre dimensions.  The small size of these particles endows them with unusual structural and optical properties that may find application in catalysis and electro-optical devices.  Such materials may also prove valuable as precursor phases to strong ceramics.  Many approaches to the synthesis of these materials have focused on constraining the reaction environment through the use of surface-bound organic groups 1, polymers 2,3, porous glasses 4,5, zeolites 6, phospholipid vesicles 7,8 and reverse micelles 9. Nanometre-sized particles may also be produced in vivo by microorganisms 10.  Here we describe a novel synthetic route based on the use of a supramolecular protein structure as a reaction cage in which to form inorganic phases. We show that the iron-storage protein ferritin can be used to generate nanometre-sized iron sulphide particles by in situ reaction of the iron oxide core of the native ferritin.  Discrete nanoscale particles of manganese and uranium oxo-species can also be formed in the protein cavity.  Our results highlight the potential of adapting natural biomineralization processes to problems in materials science, and suggest that the use of biological molecules and their synthetic analogues in mediating solid-state reactions constitutes a promising approach to nanophase engineering.
C1 UNIV BATH,SCH CHEM,BATH BA2 7AY,AVON,ENGLAND.
C3 University of Bath
NR 15
TC 434
Z9 484
U1 0
U2 165
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 684
EP 687
DI 10.1038/349684a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700043
DA 2026-03-10
ER

PT J
AU GURURAJAN, R
   PERRYOKEEFE, H
   MELTON, DA
   WEEKS, DL
AF GURURAJAN, R
   PERRYOKEEFE, H
   MELTON, DA
   WEEKS, DL
TI THE XENOPUS LOCALIZED MESSENGER-RNA AN3 MAY ENCODE AN ATP-DEPENDENT RNA HELICASE
SO NATURE
LA English
DT Article
ID unwinding activity; factor eif-4a; protein; cloning; eggs; genes; vasa
AB THE maternal messenger RNA An3 was originally identified localized to the animal hemisphere of Xenopus laevis oocytes, eggs and early embryos 1,2.  Xenopus embryos depend on mRNA and protein present in the egg before fertilization (maternal molecules) to provide the information needed for early development.  Localization of maternal mRNA gives cells derived from different regions of the egg distinctive capacities for protein synthesis.  We show here that An3 mRNA encodes a protein with 74% identity to a protein encoded by the testes-specific mRNA PL10 found in mouse 3, which is proposed to have RNA helicase activity.  Because the gene encoding An3 mRNA is reactivated after gastrulation and remains active throughout embryogenesis 1,2, we have examined its distribution in embryonic and adult tissues.  Unlike PL10 mRNA, which is primarily restricted to the testes, An3 mRNA is broadly distributed in later development.
C1 UNIV IOWA,DEPT BIOCHEM,IOWA CITY,IA 52242.
   HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,CAMBRIDGE,MA 02138.
C3 University of Iowa; Harvard University
NR 25
TC 78
Z9 85
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 717
EP 719
DI 10.1038/349717a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700055
PM 1996140
DA 2026-03-10
ER

PT J
AU FEATHERSTONE, C
   RUSSELL, P
AF FEATHERSTONE, C
   RUSSELL, P
TI FISSION YEAST P107WEE1 MITOTIC INHIBITOR IS A TYROSINE SERINE KINASE
SO NATURE
LA English
DT Article
ID expression; proteins; mitosis
AB THE fission yeast wee1+ gene product is a dose-dependent, negative regulator of entry into mitosis 1,2. wee1+ encodes a protein of relative molecular mass 107,000 (M(r) 107K), the C-terminal third of which has strong similarities with the serine/threonine protein kinase family 2,3. Here we report that p107wee1 immune complexes phosphorylate p107wee1 equally on serine and tyrosine residues, and also phosphorylate an exogenous substrate, angiotensin II, on tyrosine. Both kinase activities are attributable to p107wee1 because they are also observed when wee1+ is expressed in heterologous systems; both are abolished by a point mutation in the ATP-binding domain, and both behave like an asymmetric monomer of M(r) 114K on gel filtration and density-gradient centrifugation. Thus the wee1+ gene product is representative of a novel class of protein kinase that phosphorylates both serine and tyrosine residues.
C1 Scripps Res Inst, RES INST, DEPT MOLEC BIOL, LA JOLLA, CA 92037 USA.
C3 Scripps Research Institute
NR 13
TC 332
Z9 374
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 808
EP 811
DI 10.1038/349808a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600062
PM 1825699
DA 2026-03-10
ER

PT J
AU FRITZ, SC
   JUGGINS, S
   BATTARBEE, RW
   ENGSTROM, DR
AF FRITZ, SC
   JUGGINS, S
   BATTARBEE, RW
   ENGSTROM, DR
TI RECONSTRUCTION OF PAST CHANGES IN SALINITY AND CLIMATE USING A DIATOM-BASED TRANSFER-FUNCTION
SO NATURE
LA English
DT Article
ID ph
AB THE prospect of global warming has focused attention on the role of palaeoecology in testing the accuracy and sensitivity of climate-model predictions, in identifying past analogues for future climate change, and in placing model-predicted climate responses in the context of natural climate variability 1,2. Proxy data for climate reconstruction can be derived from many sources, including the palaeolimnological record 3,4. In closed-basin lakes in arid and semi-arid regions, shifts in effective moisture lead to the concentration or dilution of dissolved salts, and these changes in salinity are clearly reflected in the composition of lacustrine diatom assemblages 5-8. Here we refine a previously published 9 diatom-based transfer function for the reconstruction of past changes in salinity of lakes in the northern Great Plains region of North America, and apply the refined transfer function to a late-glacial and Holocene sediment record from Devils Lake, North Dakota. Our results show that there were a number of alternations between fresh and saline conditions during the Holocene and hence demonstrate the utility of the technique in reconstructing past changes in regional climate.
C1 UCL, ENVIRONM CHANGE RES CTR, DEPT GEOG, LONDON WC1H 0AP, ENGLAND.
C3 University of London; University College London
RP FRITZ, SC (corresponding author), UNIV MINNESOTA, LIMNOL RES CTR, 310 PILLSBURY DR SE, MINNEAPOLIS, MN 55455 USA.
NR 18
TC 272
Z9 325
U1 1
U2 92
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 706
EP 708
DI 10.1038/352706a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400054
DA 2026-03-10
ER

PT J
AU SESHADRI, G
   CHUN, JKM
   BOCARSLY, AB
AF SESHADRI, G
   CHUN, JKM
   BOCARSLY, AB
TI EFFECT OF CYANIDE ON THE PHOTOELECTROCHEMICAL RESPONSE OF N-CDSE/FE(CN)6(4-/3-) ELECTROLYTIC CELLS
SO NATURE
LA English
DT Article
ID electrodes
AB PHOTOELECTROCHEMICAL cells based on cadmium chalcogenide electrodes in an aqueous ferrocyanide electrolyte 1-9 provide a model system for studying the fundamental processes associated with photo-induced interfacial charge transfer, and also hold the promise of converting solar energy to electricity and useful chemical products with high efficiency. Licht 9 has suggested that it is possible to devise n-CdSe/[Fe(CN)6(3-/4-)]aq cells with a maximum solar-energy conversion efficiency of 16.4%, which derives from an open-circuit photovoltage of approximately 1.2 V, a value that approaches the thermodynamic limiting value for a semiconductor with a bandgap of 1.7 eV. Licht suggested that improvements in energy conversion efficiency are possible by modifying the electrolyte so as to prevent chemical modification of the semiconductor surface while optimizing the equilibrium concentrations of critical solution species. Here we report that addition of KCN to a ferro/ferricyanide electrolyte does not prevent surface modification on either the (112BAR0) face of n-CdX (where X is S or Se) or the (0001) face of n-CdS. We show instead that the current-voltage response observed by Licht is due to a hidden negative-DELTA-G in the system associated with the thermodynamically 'downhill' oxidation of CN-, which accounts for as much as 700 mV of the reported 'open circuit' photovoltage.
C1 PRINCETON UNIV,FRICK LAB,DEPT CHEM,PRINCETON,NJ 08544.
C3 Princeton University
NR 14
TC 25
Z9 25
U1 0
U2 17
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 508
EP 510
DI 10.1038/352508a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600054
DA 2026-03-10
ER

PT J
AU DEANGELIS, GC
   OHZAWA, I
   FREEMAN, RD
AF DEANGELIS, GC
   OHZAWA, I
   FREEMAN, RD
TI DEPTH IS ENCODED IN THE VISUAL-CORTEX BY A SPECIALIZED RECEPTIVE-FIELD STRUCTURE
SO NATURE
LA English
DT Article
ID cat striate cortex; spatial-frequency; local stereopsis; binocular interaction; simple cells; vision; model; discrimination; organization; selectivity
AB BINOCULAR neurons in the visual cortex are thought to perform the first stage of processing for the fine stereoscopic depth discrimination exhibited by animals with frontally located eyes.  Because lateral separation of the eyes gives a slightly different view to each eye, there are small variations in position (disparities), mainly along the horizontal dimension, between corresponding features in the two retinal images.  The visual system uses these disparities to gauge depth.  We studied neurons in the cat's visual cortex to determine whether the visual system uses the anisotropy in the range of horizontal and vertical disparities.  We report here that there is a corresponding anisotropy in the cortical representation of binocular information:  receptive-field profiles for left and right eyes are matched for cells that are tuned to horizontal orientations of image contours.  For neurons tuned to vertical orientations, left and right receptive fields are predominantly dissimilar.  Therefore, a major modification is required of the conventional notion of disparity processing.  The modified scheme allows a unified encoding of monocular form and binocular disparity information.
C1 UNIV CALIF BERKELEY,SCH OPT,BIOENGN GRP,BERKELEY,CA 94720.
   UNIV CALIF BERKELEY,SCH OPT,NEUROBIOL GRP,BERKELEY,CA 94720.
C3 University of California System; University of California Berkeley; University of California System; University of California Berkeley
NR 25
TC 222
Z9 244
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 156
EP 159
DI 10.1038/352156a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700057
PM 2067576
DA 2026-03-10
ER

PT J
AU REGUEIRO, MN
   MONCEAU, P
   RASSAT, A
   BERNIER, P
   ZAHAB, A
AF REGUEIRO, MN
   MONCEAU, P
   RASSAT, A
   BERNIER, P
   ZAHAB, A
TI ABSENCE OF A METALLIC PHASE AT HIGH-PRESSURES IN C60
SO NATURE
LA English
DT Article
AB THE bonding between molecules in bulk solid C60 is extremely weak, making it a narrow-band semiconductor with an energy gap of 1.5 eV (ref. 1) for the face-centred cubic phase. Doping with alkali metals produces a metallic state which can be superconducting at temperatures as high as 33 K (ref. 2). The intermolecular coupling should have an important influence on the conductivity of the pure, semiconducting state: stronger coupling might induce a transition to a metallic or possibly even superconducting state, as is the case for silicon 3, or it may result in a covalent solid such as diamond 4. We have explored these possibilities by measuring the electrical resistivity of solid granular C60 up to pressures of 25 GPa. Our results show that the magnitude of the gap and the resistivity decrease with increasing pressures as the sample volume 5 decreases. But eventual gap closure to give a metallic state is not observed; instead, there is a sudden transition at 15-20 GPa to a more insulating phase, possibly with covalent intermolecular bonding.
C1 NORMALE SUPER,ACTIVAT MOLEC LAB,F-75231 PARIS,FRANCE.
   UNIV MONTPELLIER,DYNAM PHASES CONDENSEES GRP,F-34060 MONTPELLIER,FRANCE.
C3 Universite de Montpellier
RP REGUEIRO, MN (corresponding author), CNRS,CTR RECH TRES BASSES TEMP,BP 166X CEDEX 9,F-38042 GRENOBLE,FRANCE.
NR 15
TC 73
Z9 74
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 289
EP 291
DI 10.1038/354289a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400041
DA 2026-03-10
ER

PT J
AU COOPER, E
   COUTURIER, S
   BALLIVET, M
AF COOPER, E
   COUTURIER, S
   BALLIVET, M
TI PENTAMERIC STRUCTURE AND SUBUNIT STOICHIOMETRY OF A NEURONAL NICOTINIC ACETYLCHOLINE-RECEPTOR
SO NATURE
LA English
DT Article
ID affinity binding-site; functional expression; noncompetitive blockers; h-3 chlorpromazine; xenopus oocytes; alpha-subunit; ion channel; cdna; brain; sequence
AB NEURONAL nicotinic acetylcholine receptors are members of a gene family of ligand-gated transmitter receptors that includes muscle nicotinic receptors, GABA(A) receptors and glycine receptors 1-4.  Several lines of evidence indicate that neuronal nicotinic receptors can be made up of only two subunits, an alpha (alpha) subunit which binds ligand, and a non-alpha (n-alpha) or beta (beta) subunit 5-13.  The stoichiometry of each subunit in the functional receptor has been difficult to assess, however.  Estimates of the molecular weight of neuronal nicotinic receptor macromolecules suggest that these receptors contain at least four subunits but probably not more than five 5,12.  We have examined the subunit stoichiometry of the chick neuronal alpha-4/n-alpha-1 receptor 7,9 by first using site-directed mutagenesis to create subunits that confer different single channel properties on the receptor. Co-injection with wild-type and mutant subunits led to the appearance of receptors with wild-type, mutant and hybrid conductances.  From the number of hybrid conductances, we could deduce the number of each subunit in the functional receptor.
C1 UNIV GENEVA,DEPT BIOCHEM,CH-1211 GENEVA 4,SWITZERLAND.
C3 University of Geneva
RP COOPER, E (corresponding author), MCGILL UNIV,DEPT PHYSIOL,MONTREAL H3G 1YG,QUEBEC,CANADA.
NR 24
TC 418
Z9 488
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 235
EP 238
DI 10.1038/350235a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900059
PM 2005979
DA 2026-03-10
ER

PT J
AU KNIGHT, MR
   CAMPBELL, AK
   SMITH, SM
   TREWAVAS, AJ
AF KNIGHT, MR
   CAMPBELL, AK
   SMITH, SM
   TREWAVAS, AJ
TI TRANSGENIC PLANT AEQUORIN REPORTS THE EFFECTS OF TOUCH AND COLD-SHOCK AND ELICITORS ON CYTOPLASMIC CALCIUM
SO NATURE
LA English
DT Article
ID suspended callus-cultures; elicitation; expression
AB METHODS for measuring plant cytoplasmic calcium using microelectrodes or microinjected fluorescent dyes are associated with extensive technical problems, so measurements have been limited to single or small groups of cells in tissue strips or protoplasts 1,2. Aequorin is a calcium-sensitive luminescent protein 3 from the coelenterate Aequorea victoria (A. forskalea) which is formed from apoaequorin, a polypeptide of relative molecular mass approximately 22,000, and coelenterazine, a hydrophobic luminophore 4. Microinjected aequorin has been widely used for intracellular calcium measurement in animal cells 4, but its use in plants has been limited to exceptionally large cells 5. We show here that aequorin can be reconstituted in transformed plants and that it reports calcium changes induced by touch, cold-shock and fungal elicitors. Reconstituted aequorin is cytoplasmic and nonperturbing; measurements can be made on whole plants and a calcium indicator can be constituted in every viable cell. Now that apoaequorin can be targeted to specific organelles, cells and tissues, with the range of coelenterazines with differing calcium sensitivities and properties available 6, this new method could be valuable for determining the role of calcium in intracellular signalling processes in plants.
C1 UNIV WALES COLL MED, DEPT MED BIOCHEM, CARDIFF CF4 4XN, S GLAM, WALES.
C3 Cardiff University
RP KNIGHT, MR (corresponding author), UNIV EDINBURGH, INST CELL & MOLEC BIOL, EDINBURGH EH9 3JH, MIDLOTHIAN, SCOTLAND.
NR 25
TC 989
Z9 1115
U1 5
U2 130
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 524
EP 526
DI 10.1038/352524a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600061
PM 1865907
DA 2026-03-10
ER

PT J
AU GUTHRIE, PB
   SEGAL, M
   KATER, SB
AF GUTHRIE, PB
   SEGAL, M
   KATER, SB
TI INDEPENDENT REGULATION OF CALCIUM REVEALED BY IMAGING DENDRITIC SPINES
SO NATURE
LA English
DT Article
ID long-term potentiation; synaptic transmission; pyramidal cells; hippocampal; neurons; accumulation; 4-aminopyridine; stimulation; enhancement; microscopy
AB THE dendritic spine is a basic structural unit of neuronal organization. It is assumed to be a primary locus of synaptic plasticity, and to undergo long-term morphological and functional changes 1-6, at least some of which are regulated by intracellular calcium concentrations 7-11. It is known that physiological stimuli can cause marked increases in intracellular calcium levels in hippocampal dendritic shafts 12,13, but it is completely unknown to what extent such changes in the dendrites would also be seen by calcium-sensing structures within spines. Will calcium levels in all spines change in parallel with the dendrite or will there be a heterogeneous response? This study, through direct visualization and measurement of intracellular calcium concentrations in individual living spines, demonstrates that experimentally evoked changes in calcium concentrations in the dendritic shaft ([Ca2+]d) are frequently not parallelled in the spine ([Ca2+]s). This isolation is not caused by a physical diffusion barrier. This report provides, to our knowledge, the first direct demonstration of autonomous spine function.
C1 COLORADO STATE UNIV, DEPT ANAT & NEUROBIOL, PROGRAM NEURONAL GROWTH & DEV, FT COLLINS, CO USA.
   WEIZMANN INST SCI, CTR NEUROSCI, IL-76100 REHOVOT, ISRAEL.
C3 Colorado State University System; Colorado State University Fort Collins; Weizmann Institute of Science
NR 32
TC 218
Z9 230
U1 0
U2 6
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 76
EP 80
DI 10.1038/354076a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900062
PM 1944573
DA 2026-03-10
ER

PT J
AU SHIBATA, K
   MATSUMOTO, R
AF SHIBATA, K
   MATSUMOTO, R
TI FORMATION OF GIANT MOLECULAR CLOUDS AND HELICAL MAGNETIC-FIELDS BY THE PARKER INSTABILITY
SO NATURE
LA English
DT Article
ID nonuniform gravitational-fields; complexes; orion
AB USING the Nagoya telescope 1, Uchida et al. 2 found an unusual helical filamentary structure, spinning about its long axis, in the L1641 cloud in the Orion cloud complex. Noting that this structure is consistent with a helically twisted magnetic field inferred from optical polarization observations 3,4, they argued that the helical filament is a manifestation of torsional magnetohydrodynamic (Alfven) waves draining angular momentum from a nearby massive cloud, thus promoting collapse and star formation. Here we present an alternative interpretation. We suggest that the Orion molecular cloud complex formed through the Parker instability 5 (the buoyancy of a magnetic field entrained in matter), and that the helical filament is the result of spinning gas falling along the magnetic field and twisting it. The twisted magnetic field, unlike a purely planar field, suppresses the Parker instability on small scales, allowing the generation of finite clouds rather than general turbulence.
C1 CHIBA UNIV,COLL ARTS & SCI,CHIBA 260,JAPAN.
   AICHI UNIV EDUC,DEPT PHYS & ASTRON,KARIYA,AICHI 448,JAPAN.
C3 Chiba University; Aichi University Education
NR 23
TC 45
Z9 48
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 633
EP 635
DI 10.1038/353633a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200059
DA 2026-03-10
ER

PT J
AU EOM, CB
   MARSHALL, AF
   SUZUKI, Y
   BOYER, B
   PEASE, RFW
   GEBALLE, TH
AF EOM, CB
   MARSHALL, AF
   SUZUKI, Y
   BOYER, B
   PEASE, RFW
   GEBALLE, TH
TI ABSENCE OF WEAK-LINK BEHAVIOR IN YBA2CU3O7 GRAINS CONNECTED BY 90-DEGREES [010] TWIST BOUNDARIES
SO NATURE
LA English
DT Article
ID bicrystals; films
AB ONE of the obstacles to developing applications of the high-T(c) copper oxide superconductors is the low critical current density (J(c)) of the bulk polycrystalline materials, due to the presence of grain boundaries.  On the other hand, these same grain boundaries can be put to good use in device applications, where their low J(c) allows them to be used as 'weak links' in Josephson junctions 1,2.  Dimos et al. 3,4 have shown that the transport properties of certain twist and tilt boundaries degrade as the misorientation angle increases, suggesting that high-angle grain boundaries are generally deleterious to the overall J(c).  More recently, however, Babcock et al. 5 reported weak-link-free behaviour at high magnetic field in an YBa2Cu3O7-delta (YBCO) bicrystal containing two kinds of 90-degrees boundary; they were not able to distinguish between the characteristics of the two types, which were electrically in parallel.  Here we report the observation of 90-degrees [010] twist boundaries in {103}-oriented YBCO thin films.  (Because of the twin microstructure, we do not distinguish between the a and b axes).  Across these boundaries the J(c) and normal-state conductivity are as high as those of high-quality c-axis-oriented films with no high-angle grain boundaries.
C1 STANFORD UNIV,DEPT APPL PHYS,STANFORD,CA 94305.
   STANFORD UNIV,CTR ELECT ENGN,STANFORD,CA 94305.
   STANFORD UNIV,DEPT ELECT ENGN,STANFORD,CA 94305.
C3 Stanford University; Stanford University; Stanford University
NR 10
TC 79
Z9 79
U1 2
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 544
EP 547
DI 10.1038/353544a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300061
DA 2026-03-10
ER

PT J
AU ABO, A
   PICK, E
   HALL, A
   TOTTY, N
   TEAHAN, CG
   SEGAL, AW
AF ABO, A
   PICK, E
   HALL, A
   TOTTY, N
   TEAHAN, CG
   SEGAL, AW
TI ACTIVATION OF THE NADPH OXIDASE INVOLVES THE SMALL GTP-BINDING PROTEIN P21RAC1
SO NATURE
LA English
DT Article
ID chronic granulomatous-disease; cell-free system; 2 cytosolic components; sodium dodecyl-sulfate; dependent superoxide production; human-neutrophils; plasma-membrane; cytochrome-b; guanine-nucleotides; respiratory burst
AB PROFESSIONAL phagocytes, such as neutrophils and monocytes, have an NADPH oxidase that generates superoxide and other reduced oxygen species important in killing microorganisms (reviewed in ref. 1). Several components of the oxidase complex have been identified as targets of genetic defects causing chronic granulomatous disease 2-4. The complex consists of an electron transport chain that has as its substrate cytosolic NADPH and which discharges superoxide into the cavity of the intracellular phagocytic vacuole. The only electron transport component identified so far is a low-potential cytochrome b (refs 5, 6), apparently the only membrane component required 7. At least three cytosolic factors are also necessary, two of which, p67phox and p47phox, have been identified by their absence in patients with chronic granulomatous disease 8-11. A third component, sigma-1 (refs 12, 13), is required for stimulation of oxidase activity in a cell-free system 14-16. The active components of purified sigma-1 are two proteins that associate as heterodimers 17, and here we report that these are the small GTP-binding protein p2lrac1 and the GDP-dissociation inhibitor rhoGDI.
C1 INST CANC RES,CHESTER BEATTY LABS,LONDON SW3 6JB,ENGLAND.
   LUDWIG INST CANC RES,LONDON W1P 8BT,ENGLAND.
   UNIV LONDON UNIV COLL,RAYNE INST,DEPT MED,LONDON WC1E 6JJ,ENGLAND.
C3 Royal Marsden NHS Foundation Trust; University of London; Institute of Cancer Research - UK; Ludwig Institute for Cancer Research; University of London; University College London; King's College London
RP ABO, A (corresponding author), TEL AVIV UNIV,SACKLER SCH MED,IMMUNOPHARMACOL LAB,TEL AVIV,ISRAEL.
FU Wellcome Trust Funding Source: Medline
NR 39
TC 873
Z9 945
U1 1
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 668
EP 670
DI 10.1038/353668a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200074
PM 1922386
DA 2026-03-10
ER

PT J
AU DOORBAR, J
   ELY, S
   STERLING, J
   MCLEAN, C
   CRAWFORD, L
AF DOORBAR, J
   ELY, S
   STERLING, J
   MCLEAN, C
   CRAWFORD, L
TI SPECIFIC INTERACTION BETWEEN HPV-16 E1-E4 AND CYTOKERATINS RESULTS IN COLLAPSE OF THE EPITHELIAL-CELL INTERMEDIATE FILAMENT NETWORK
SO NATURE
LA English
DT Article
ID human papillomavirus type-16; open reading frames; human keratinocytes; vaccinia virus; proteins; e4; identification; transformation; l1; cytoskeleton
AB THE human papillomaviruses (HPV) are associated specifically with epithelial lesions, ranging from benign warts to invasive carcinoma (for review, see refs 1, 2).  The virus encodes three late proteins, which are produced only in terminally differentiating keratinocytes, two of which are structural components of the virion 3.  The third, E1-E4, is derived primarily from the E4 open reading frame, which represents a region of maximal divergence between different HPV types 4,5.  E1-E4 does not seem to be a component of the virus particle or to be needed for transformation in vitro 6,7, but accumulates in the cytoplasm 5,8-10, where in certain benign lesions it can comprise 20-30% of total cell protein 4,10.  We show here that expression of the HPV-16 E1-E4 protein in human keratinocytes (the natural host cell for HPV infection) results in the total collapse of the cytokeratin matrix.  Tubulin and actin networks are unaffected by E1-E4, as are the nuclear lamins.
RP DOORBAR, J (corresponding author), UNIV CAMBRIDGE,DEPT PATHOL,IMPERIAL CANC RES FUND,TUMOUR VIRUS GRP,TENNIS COURT RD,CAMBRIDGE CB2 1QP,ENGLAND.
NR 27
TC 232
Z9 320
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 824
EP 827
DI 10.1038/352824a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400067
PM 1715519
DA 2026-03-10
ER

PT J
AU BAKER, SC
   KELLY, DP
   MURRELL, JC
AF BAKER, SC
   KELLY, DP
   MURRELL, JC
TI MICROBIAL-DEGRADATION OF METHANESULFONIC-ACID - A MISSING LINK IN THE BIOGEOCHEMICAL SULFUR CYCLE
SO NATURE
LA English
DT Article
ID methanesulfonic-acid; dimethylsulfide; sulfide
AB ATMOSPHERIC dimethyl sulphide, arising from marine algae, cyanobacteria and salt marsh plants such as Spartina, is the principal sulphur compound entering the atmosphere from terrestrial and aquatic environments 1-6. Methanesulphonic acid (CH3SO3H; MSA) has been identified as a major product of the photochemical oxidation in the atmosphere of dimethyl sulphide 1-3, 5, 7-9. Dimethyl sulphide and MSA are thus predominantly, if not exclusively, biogenic in origin, and are the main gaseous links in the biogeochemical sulphur cycle. MSA is a stable compound, not undergoing photochemical decomposition 3, so its removal from the atmosphere is by wet and dry deposition. MSA partitions into the aerosol phase, as well as nucleating droplet formation, and is deposited in rain and snow. Analysis of Antarctic ice cores 10 gives evidence of its global deposition over many thousands of years. The subsequent fate of MSA deposited on land was unknown. Here we describe terrestrial bacteria that grow on MSA. Their activities in the natural environment would result in the mineralization of MSA to carbon dioxide and sulphate, thus completing our understanding of this part of the sulphur cycle.
C1 NERC, SWINDON SN2 1EU, ENGLAND.
C3 UK Research & Innovation (UKRI); Natural Environment Research Council (NERC)
RP BAKER, SC (corresponding author), UNIV WARWICK, DEPT BIOL SCI, COVENTRY CV4 7AL, W MIDLANDS, ENGLAND.
NR 21
TC 109
Z9 116
U1 2
U2 23
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 627
EP 628
DI 10.1038/350627a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200065
DA 2026-03-10
ER

PT J
AU WILCOCK, D
   LANE, DP
AF WILCOCK, D
   LANE, DP
TI LOCALIZATION OF P53, RETINOBLASTOMA AND HOST REPLICATION PROTEINS AT SITES OF VIRAL REPLICATION IN HERPES-INFECTED CELLS
SO NATURE
LA English
DT Article
ID simplex virus type-1; dna-binding-protein; large tumor-antigen; monoclonal-antibody; gene-product; sv40-transformed cells; susceptibility gene; auxiliary protein; polymerase-delta; nuclear antigen
AB REPLICATION of DNA occurs at DNA occurs at discrete sites in eukaryotic cell nuclei, where replication proteins are clustered into large complexes, or 'replicases' 1-3.  Similarly, viral DNA replication is a highly structured process, notably in herpes simplex virus type-1 (HSV-1; reviewed in ref. 4) in which large globular "replication compartments' containing the viral replication machinery exist. Replicating cellular DNA redistributes to these compartments upon HSV-1 infection 5.  We have now used antibodies raised against several cellular proteins to detect changes in their subnuclear localization on HSV-1 infection.  We found that various proteins involved in cellular DNA replication move to sites of viral DNA synthesis, whereas a selection of non-replication proteins do not.  The retinoblastoma protein and p53 (the products of two putative anti-oncogenes 6.7) relocate to the same sites as known DNA replication proteins, suggesting that they may be associated with DNA replication complexes in normal, uninfected cells.
RP WILCOCK, D (corresponding author), IMPERIAL CANC RES FUND,CLARE HALL LABS,POTTERS BAR EN6 3LD,HERTS,ENGLAND.
NR 42
TC 256
Z9 278
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 429
EP 431
DI 10.1038/349429a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400056
PM 1671528
DA 2026-03-10
ER

PT J
AU BEARD, KC
   KRISHTALKA, L
   STUCKY, RK
AF BEARD, KC
   KRISHTALKA, L
   STUCKY, RK
TI 1ST SKULLS OF THE EARLY EOCENE PRIMATE SHOSHONIUS-COOPERI AND THE ANTHROPOID-TARSIER DICHOTOMY
SO NATURE
LA English
DT Article
ID origins; omomyidae; evolution; tarsiidae; africa
AB THE phylogenetic relationships of living tarsiers and extinct omomyid primates are critical for deciphering the origin and relationships of primate higher taxa, particularly anthropoids1-6.  Three competing phylogenetic hypotheses are:  (1) tarsiers are most closely related to early Cenozoic Omomyidae5-8, particularly genera such as Necrolemur from the late Eocene of Europe9-11; (2) tarsiers share a more recent common ancestry with anthropoids than they do with any known omoyid2-4,12,13; (3) tarsiers and/or omoyids are most closely related to strepsirhines14. The anatomy of four skulls of the early Eocene omomyid Shoshonius cooperi-the first cranial material recovered for this genus-strongly suggests that Schoshonius shares a more recent common ancestry with Tarsius than do either anthropoids or other Eocene omomyids for which cranial anatomy is known.  If the primate suborder Haplorhini (anthropoids, omomyids, tarsiids) is monophyletic, the phylogenetic position of Shoshonius requires that anthropoids and Tarsius diverged by at least the early Eocene, some 15 million years before the first appearance of anthropoids in the fossil record15-17.
C1 DENVER MUSEUM NAT HIST,DEPT EARTH SCI,DENVER,CO 80205.
RP BEARD, KC (corresponding author), CARNEGIE MUSEUM NAT HIST,VERTEBRATE PALEONTOL SECT,4400 FORBES AVE,PITTSBURGH,PA 15213, USA.
NR 32
TC 60
Z9 70
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 64
EP 67
DI 10.1038/349064a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100051
PM 1985267
DA 2026-03-10
ER

PT J
AU LUSSO, P
   DEMARIA, A
   MALNATI, M
   LORI, F
   DEROCCO, SE
   BASELER, M
   GALLO, RC
AF LUSSO, P
   DEMARIA, A
   MALNATI, M
   LORI, F
   DEROCCO, SE
   BASELER, M
   GALLO, RC
TI INDUCTION OF CD4 AND SUSCEPTIBILITY TO HIV-1 INFECTION IN HUMAN CD8+ LYMPHOCYTES-T BY HUMAN HERPESVIRUS-6
SO NATURE
LA English
DT Article
ID acquired immunodeficiency syndrome; cells; virus; expression; antigen; gene; differentiation; cytomegalovirus; individuals; retrovirus
AB DURING intrathymic T-cell ontogenesis, functionally competent CD3+CD4+CD8- and CD3+CD4-CD8+ T lymphocytes develop from immature CD4-CD8- thymocytes after transiently acquiring a double-positive CD4+CD8+ phenotype 1-3.  The partition between CD4+CD8- and CD4-CD8+ T cells is generally considered to be irreversible, although a small percentage of circulating CD3+ T lymphocytes coexpressing CD4 and CD8 molecules has been identified 4.  It has been suggested that in CD8+ T cells the CD4 genes may be methylated and thus highly repressed 5, whereas in CD4+ T cells the CD8 genes are unmethylated 6 and their transcription can be induced by physiological stimuli such as interleukin-4 (ref. 7).  Here, we demonstrate that infection with human herpesvirus 6 (HHV-6) (ref. 8), a virus proposed as a potential cofactor in AIDS (ref. 9), dramatically upregulates the expression of CD4-the receptor for human immunodeficiency virus type-1 (HIV-1) (refs 10-12)-in a human neoplastic T-cell line.  More importantly, HHV-6 induces de novo expression of CD4 messenger RNA and protein in normal mature CDE8+ T lymphocytes, rendering them susceptible to infection with HIV-1.  These findings demonstrate that human CD3+CD4-CD8+ T lymphocytes can reacquire CD4 in the post-thymic life and elucidate a novel mechanism-receptor regulation-through which HHV-6 may positively interact with HIV-1 in coinfected patients.
C1 NIAID,IMMUNOREGULAT LAB,BETHESDA,MD 20892.
   NCI,FREDERICK CANC RES FACIL,PROGRAM RESOURCES INC,FREDERICK,MD 21701.
   NIAID,IMMUNOGENET LAB,BETHESDA,MD 20892.
   ADV BIOSCI LABS,DEPT CELL BIOL,KENSINGTON,MD 20895.
C3 National Institutes of Health (NIH) - USA; NIH National Institute of Allergy & Infectious Diseases (NIAID); National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); National Institutes of Health (NIH) - USA; NIH National Institute of Allergy & Infectious Diseases (NIAID)
RP LUSSO, P (corresponding author), NCI,TUMOR CELL BIOL LAB,BETHESDA,MD 20892, USA.
NR 30
TC 248
Z9 262
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 533
EP 535
DI 10.1038/349533a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100070
PM 1846951
DA 2026-03-10
ER

PT J
AU KUHLBRANDT, W
   WANG, DN
AF KUHLBRANDT, W
   WANG, DN
TI 3-DIMENSIONAL STRUCTURE OF PLANT LIGHT-HARVESTING COMPLEX DETERMINED BY ELECTRON CRYSTALLOGRAPHY
SO NATURE
LA English
DT Article
ID a/b-protein complex; photosynthetic reaction center; rhodopseudomonas-viridis; sensitive specimens; purple membrane; chlorophyll; resolution; micrographs; crystals; beam
AB The structure of the light-harvesting chlorophyll a/b-protein complex, a membrane protein serving as the major antenna of solar energy in plant photosynthesis, has been determined at 6 angstrom resolution by electron crystallography.  Within the complex, three membrane-spanning alpha-helices and 15 chlorophyll molecules are resolved.  There is an intramolecular diad relating two of the alpha-helices and some of the chlorophylls.  The spacing of the chlorophylls suggests energy transfer by delocalized exciton coupling and Forster mechanisms.
RP KUHLBRANDT, W (corresponding author), EUROPEAN MOLEC BIOL LAB,MEYERHOFSTR 1,W-6900 HEIDELBERG,GERMANY.
NR 39
TC 433
Z9 457
U1 0
U2 46
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 130
EP 134
DI 
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500048
PM 2005962
DA 2026-03-10
ER

PT J
AU LORENZ, EN
AF LORENZ, EN
TI DIMENSION OF WEATHER AND CLIMATE ATTRACTORS
SO NATURE
LA English
DT Article
ID strange attractors; short timescales; systems; chaos
AB A PROCEDURE for estimating the correlation dimension of the attractor of a dynamical system 1 has been applied to a number of data sets that are representative of weather or climate variations. Reported values of the attractor dimension have typically fallen between 3.0 and 8.0 (refs 2-9). Because the atmosphere is so complex, these values have seemed surprisingly low, and doubts as to their appropriateness have been expressed even by the originators of the method 8,10,11. Here I apply the procedure to 'data' generated by a mathematical system whose dimension can be evaluated by other means, and identify conditions, apparently satisfied by the studies that use real data, in which the procedure will yield systematic underestimates. It therefore seems unlikely that global weather or climate systems possess low-dimensional attractors.
C1 UNIV CALIF SAN DIEGO, INST NONLINEAR SCI, LA JOLLA, CA 92093 USA.
C3 University of California System; University of California San Diego
NR 20
TC 194
Z9 202
U1 1
U2 25
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 241
EP 244
DI 10.1038/353241a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400053
DA 2026-03-10
ER

PT J
AU LOVLEY, DR
   PHILLIPS, EJP
   GORBY, YA
   LANDA, ER
AF LOVLEY, DR
   PHILLIPS, EJP
   GORBY, YA
   LANDA, ER
TI MICROBIAL REDUCTION OF URANIUM
SO NATURE
LA English
DT Article
ID iron reduction; sediments; deposition; oxidation; mechanisms; manganese; thorium; sea
AB REDUCTION of the soluble, oxidized form of uranium, U(VI), to insoluble U(IV) is an important mechanism for the immobilization of uranium in aquatic sediments and for the formation of some uranium ores 1-10.  U(VI) reduction has generally been regarded as an abiological reaction in which sulphide, molecular hydrogen or organic compounds function as the reductant 1,2,5,11.  Microbial involvement in U(VI) reduction has been considered to be limited to indirect effects, such as microbial metabolism providing the reduced compounds for abiological U(VI) reduction and microbial cell walls providing a surface to stimulate abiological U(VI) reduction 1,12,13.  We report here, however, that dissimilatory Fe(III)-reducing microorganisms can obtain energy for growth by electron transport to U(VI).  This novel form of microbial metabolism can be much faster than commonly cited abiological mechanisms for U(VI) reduction.  Not only do these findings expand the known potential terminal electron acceptors for microbial energy transduction, they offer a likely explanation for the deposition of uranium in aquatic sediments and aquifers, and suggest a method for biological remediation of environments contaminated with uranium.
RP LOVLEY, DR (corresponding author), US GEOL SURVEY,DIV WATER RESOURCES,430 NATL CTR,RESTON,VA 22092, USA.
NR 30
TC 1120
Z9 1351
U1 12
U2 332
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 413
EP 416
DI 10.1038/350413a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200046
DA 2026-03-10
ER

PT J
AU SLEZAK, SE
   MUIRHEAD, KA
AF SLEZAK, SE
   MUIRHEAD, KA
TI RADIOACTIVE CELL-MEMBRANE LABELING
SO NATURE
LA English
DT Article
ID fluorescent
RP SLEZAK, SE (corresponding author), ZYNAXIS CELL SCI,371 PHOENIXVILLE PIKE,MALVERN,PA 19355, USA.
NR 12
TC 21
Z9 23
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 261
EP 262
DI 10.1038/352261a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500073
PM 1857424
DA 2026-03-10
ER

PT J
AU LASPADA, AR
   WILSON, EM
   LUBAHN, DB
   HARDING, AE
   FISCHBECK, KH
AF LASPADA, AR
   WILSON, EM
   LUBAHN, DB
   HARDING, AE
   FISCHBECK, KH
TI ANDROGEN RECEPTOR GENE-MUTATIONS IN X-LINKED SPINAL AND BULBAR MUSCULAR-ATROPHY
SO NATURE
LA English
DT Article
ID localization; expression; cloning; family; locus; acid; opa
AB X-LINKED spinal and bulbar muscular atrophy (Kennedy's disease) is an adult-onset form of motorneuron disease which may be associated with signs of androgen insensitivity. We have now investigated whether the androgen receptor gene on the proximal long arm of the X chromosome is a candidate gene for this disease. In patient samples we found androgen receptor gene mutations with increased size of a polymorphic tandem CAG repeat in the coding region. These amplified repeats were absolutely associated with the disease, being present in 35 unrelated patients and none of 75 controls. They segregated with the disease in 15 families, with no recombination in 61 meioses (the maximum log likelihood ratio (lod score) is 13.2 at a recombination rate of 0). The association is unlikely to be due to linkage disequilibrium, because 11 different disease alleles were observed. We conclude that enlargement of the CAG repeat in the androgen receptor gene is probably the cause of this disorder.
C1 UNIV N CAROLINA,REPROD BIOL LABS,CHAPEL HILL,NC 27599.
   NATL HOSP,INST NEUROL,LONDON WC1N 3BG,ENGLAND.
C3 University of North Carolina; University of North Carolina Chapel Hill; University of London; University College London; UCL Medical School; University College London Hospitals NHS Foundation Trust; National Hospital for Neurology & Neurosurgery
RP LASPADA, AR (corresponding author), UNIV PENN,SCH MED,DEPT NEUROL,PHILADELPHIA,PA 19104, USA.
NR 19
TC 2122
Z9 2375
U1 0
U2 75
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 77
EP 79
DI 10.1038/352077a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800075
PM 2062380
DA 2026-03-10
ER

PT J
AU YANG, L
   LI, R
   MOHR, IJ
   CLARK, R
   BOTCHAN, MR
AF YANG, L
   LI, R
   MOHR, IJ
   CLARK, R
   BOTCHAN, MR
TI ACTIVATION OF BPV-1 REPLICATION INVITRO BY THE TRANSCRIPTION FACTOR E2
SO NATURE
LA English
DT Article
ID sv40 dna-replication; simian virus-40 dna; t-antigen; human-cells; protein; origin; phosphorylation; binding; complex
AB Soluble extracts from uninfected murine cells supplemented with purified viral E1 and E2 proteins support the replication of exogenously added papilloma virus DNA. The E2 transactivator stimulates the binding of the E1 replication protein to the minimal origin of replication and activates DNA replication. These results support the concept that transcription factors have a direct role in the initiation of DNA replication in eukaryotes by participating in the assembly of a complex at the origin of replication.
RP YANG, L (corresponding author), UNIV CALIF BERKELEY, DEPT MOLEC & CELL BIOL, DIV BIOCHEM & MOLEC BIOL, BERKELEY, CA 94720 USA.
NR 33
TC 282
Z9 302
U1 0
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 628
EP 632
DI 10.1038/353628a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200058
PM 1656277
DA 2026-03-10
ER

PT J
AU SPEAKMAN, JR
   RACEY, PA
AF SPEAKMAN, JR
   RACEY, PA
TI NO COST OF ECHOLOCATION FOR BATS IN FLIGHT
SO NATURE
LA English
DT Article
ID pteropus-gouldii; gas-exchange; metabolism; physiology
AB ECHOLOCATION has evolved in relatively few animal species 1.  One constraint may be the high cost of producing pulses, the echoes of which can be detected over useful distances 2.  The energy cost of echolocation in a small (6 g) insectivorous bat, when hanging at rest, was recently measured at 0.067 Joules per pulse 3, implying a mean cost for echolocation in flight of 9.5 x basal metabolic rate (range 7 to 12x).  Because flight is very costly 4, whether the costs of echolocation and flying are additive is an important question.  We measured the energy costs of flight in two species of small echolocating Microchiroptera using a novel combination of respirometry and doubly-labelled water 5.  Flight energy expenditure (adjusted for body mass) was not significantly different between echolocating bats and non-echolocating bats and birds.  The low cost of echolocation for flying vertebrates may have been a significant factor favouring its evolution in these groups.
RP SPEAKMAN, JR (corresponding author), UNIV ABERDEEN,DEPT ZOOL,ABERDEEN AB9 2TN,SCOTLAND.
NR 28
TC 185
Z9 203
U1 1
U2 54
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 421
EP 423
DI 10.1038/350421a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200049
PM 2011191
DA 2026-03-10
ER

PT J
AU COWIE, LL
   SONGAILA, A
   HU, EM
AF COWIE, LL
   SONGAILA, A
   HU, EM
TI WERE SMALL GALAXIES ONCE THE DOMINANT COSMOLOGICAL POPULATION
SO NATURE
LA English
DT Article
ID dwarf galaxy; redshift; evolution; parameter; origin
AB DEEP sky surveys have turned up unexpectedly large numbers of faint blue galaxies 1,2-three to five times more than would be estimated by extrapolation from the present galaxy population assuming no evolution. Unless distances to these faint galaxies are known, it is difficult to distinguish between luminosity evolution (in which case, galaxies in the past were systematically brighter) and density evolution (as, for example, if modern galaxies are the results of mergers of earlier ones). We have obtained redshifts and K magnitudes for a small but complete sample of 22 galaxies with B magnitude down to 24. In the luminosity range B = 23-24, the B-band galaxy counts are dominated by a population of small blue galaxies at z almost-equal-to 0.25, which may collectively contain as much baryonic matter as the normal galaxies. It is possible either that these earlier galaxies have undergone merging 3 to create the present galaxy population, or that they represent a quite different galactic population which has now faded or disappeared 4. Either possibility has considerable implications for our understanding of galaxy formation.
RP COWIE, LL (corresponding author), UNIV HAWAII, INST ASTRON, 2680 WOODLAWN DR, HONOLULU, HI 96822 USA.
NR 17
TC 180
Z9 180
U1 0
U2 1
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 460
EP 461
DI 10.1038/354460a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800052
DA 2026-03-10
ER

PT J
AU STARK, CP
AF STARK, CP
TI AN INVASION PERCOLATION MODEL OF DRAINAGE NETWORK EVOLUTION
SO NATURE
LA English
DT Article
ID fractal dimension; stream networks; diffusion; growth; aggregation; clusters
AB STREAM networks evolve by headward growth and branching away from escarpments such as rift margins. The structure of these networks and their topographic relief are known to be fractal 1-3, but no model so far bas been able to generate the observed scaling properties. Here I present a statistical model of network growth in which stream heads branch and propagate at a rate that depends only on the local strength of the substrate. This model corresponds to the process of invasion percolation 4, with the added requirement of self-avoidance; it is a self-organized critical system 5 with properties similar to those of standard percolation models 6.  A description based on self-avoiding invasion percolation reproduces the known scaling behaviour of stream networks, and may provide a valuable tool for delineation of drainage patterns from digital topographic data sets 7,8.
RP STARK, CP (corresponding author), UNIV LEEDS,DEPT EARTH SCI,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND.
NR 28
TC 92
Z9 99
U1 1
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 423
EP 425
DI 10.1038/352423a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600061
DA 2026-03-10
ER

PT J
AU HESS, JF
   PARISI, MA
   BENNETT, JL
   CLAYTON, DA
AF HESS, JF
   PARISI, MA
   BENNETT, JL
   CLAYTON, DA
TI IMPAIRMENT OF MITOCHONDRIAL TRANSCRIPTION TERMINATION BY A POINT MUTATION ASSOCIATED WITH THE MELAS SUBGROUP OF MITOCHONDRIAL ENCEPHALOMYOPATHIES
SO NATURE
LA English
DT Article
ID transfer rnalys; dna-sequence; binding; invitro; purification; selection; epilepsy; genome
AB DEFECTS in mitochondrial DNA (mtDNA) are associated with several different human diseases, including the mitochondrial encephalomyopathies.  The mutations include deletions but also duplications and point mutations 1.  Individuals with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) carry a common A-to-G substitution in a highly conserved portion of the gene for transfer RNA(Leu(UUR)) (refs 2, 3).  Although the MELAS mutation may be comparable to the defect in the tRNA(Lys) gene associated with MERRF (refs 4, 5) (myoclonus epilepsy associated with ragged-red fibres), it is also embedded in the middle of a tridecamer sequence necessary for the formation of the 3' ends of 16S ribosomal RNA in vitro 6.  We found that the MELAS mutation results in severe impairment of 16S rRNA transcription termination, which correlates with a reduced affinity of the partially purified termination protein for the MELAS template.  This suggests that the molecular defect in MELAS is the inability to produce the correct type and quantity of rRNA relative to other mitochondrial gene products.
C1 STANFORD UNIV,MED CTR,SCH MED,DEPT DEV BIOL,STANFORD,CA 94305.
C3 Stanford University
NR 19
TC 221
Z9 226
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 236
EP 239
DI 10.1038/351236a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000058
PM 1755869
DA 2026-03-10
ER

PT J
AU SMITH, MG
   MANTHIRAM, A
   ZHOU, J
   GOODENOUGH, JB
   MARKERT, JT
AF SMITH, MG
   MANTHIRAM, A
   ZHOU, J
   GOODENOUGH, JB
   MARKERT, JT
TI ELECTRON-DOPED SUPERCONDUCTIVITY AT 40-K IN THE INFINITE-LAYER COMPOUND SR1-YNDYCUO2
SO NATURE
LA English
DT Article
ID copper oxides; pr
AB THE known copper oxide superconductors all have intergrowth structures consisting of superconducting layers of fixed oxygen content alternating with non-superconducting oxide layers.  Siegrist et al. 1 reported the synthesis of the 'infinite-layer' parent compound of the copper oxide superconductor - a structure comprising CuO2 planes separated only by calcium and strontium atoms, with the composition Ca0.86Sr0.14CuO2. Although this compound has not been made to superconduct, here we show that the isostructural compound Sr(1-y)Nd(y)CuO2, in which the substitution of neodymium for strontium adds electrons to the CuO2 planes, is superconducting at 40 K.  The difference in dopant type seems to distinguish this superconductor from the superconductivity found in a multiphase sample of nominal composition Sr(1-y)Ba(y)CuO2 by Takano et al. 2, in an independent study.
C1 UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712.
C3 University of Texas System; University of Texas Austin
RP SMITH, MG (corresponding author), UNIV TEXAS,CTR MAT SCI & ENGN,ETC 5160,AUSTIN,TX 78712, USA.
NR 10
TC 402
Z9 417
U1 1
U2 66
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 549
EP 551
DI 10.1038/351549a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400051
DA 2026-03-10
ER

PT J
AU GRAUR, D
   HIDE, WA
   LI, WH
AF GRAUR, D
   HIDE, WA
   LI, WH
TI IS THE GUINEA-PIG A RODENT
SO NATURE
LA English
DT Article
ID amino-acid-sequences; molecular evolution; ribonuclease; phylogeny; nucleotide; gene
AB THE guinea-pig (Cavia porcellus), traditionally classified as a New World hystricomorph rodent, often shows anomalous morphological and molecular features in comparison with other eutherian mammals 1-14. For example, its insulin differs from that of other mammals in anabolic and growth-promoting activities and in its capability to form hexamers 5, 6. Indeed, the literature about the molecular evolution of guinea-pigs abounds in references to 'convergent evolution', 'extremely rapid rates of substitution', and 'unique evolutionary mechanisms'. These claims are based on the assumption that the guinea-pig is a rodent. Our phylogenetic analyses of amino-acid sequence data, however, imply that the guinea-pig diverged before the separation of the primates and the artiodactyls from the myomorph rodents (rats and mice). If true, then the myomorphs and the caviomorphs do not constitute a natural clade, and the Caviomorpha (or the Histricomorpha) should be elevated in taxonomical rank and regarded as a separate mammalian order distinct from the Rodentia. If, as suggested by recent data 15, 16, the myomorphs branched off before the divergence among the carnivores, lagomorphs, artiodactyls and primates, then the new order would represent an early divergence in eutherian radiation.
C1 UNIV TEXAS, CTR DEMOG & POPULAT GENET, POB 20334, HOUSTON, TX 77225 USA.
   TEL AVIV UNIV, GEORGE S WISE FAC LIFE SCI, DEPT ZOOL, IL-69978 TEL AVIV, ISRAEL.
   BAYLOR UNIV, DEPT CELL BIOL, HOUSTON, TX 77030 USA.
C3 University of Texas System; University of Texas Health Science Center Houston; Tel Aviv University; Baylor University
NR 25
TC 279
Z9 296
U1 0
U2 26
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 649
EP 652
DI 10.1038/351649a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200065
PM 2052090
DA 2026-03-10
ER

PT J
AU POUVELLE, B
   SPIEGEL, R
   HSIAO, L
   HOWARD, RJ
   MORRIS, RL
   THOMAS, AP
   TARASCHI, TF
AF POUVELLE, B
   SPIEGEL, R
   HSIAO, L
   HOWARD, RJ
   MORRIS, RL
   THOMAS, AP
   TARASCHI, TF
TI DIRECT ACCESS TO SERUM MACROMOLECULES BY INTRAERYTHROCYTIC MALARIA PARASITES
SO NATURE
LA English
DT Article
ID falciparum-infected erythrocytes; plasmodium-falciparum; transport; membrane; protein; culture
AB TRAFFICKING pathways in malaria-infected erythrocytes are complex because the internal parasite is separated from the serum by the erythrocyte and parasitophorous vacuolar membranes 1. Intraerythrocytic Plasmodium falciparum parasites can endocytose dextrans, protein A and an IgG2a antibody. Here we show that these macromolecules do not cross the erythrocyte or parasitophorous vacuolar membranes, but rather gain direct access to the aqueous space surrounding the parasite through a parasitophorous duct. Evidence for this structure includes visualization of membranes that are continuous between the parasitophorous vacuolar and erythrocyte membranes, and surface labelling of the parasite with fluorescent macromolecules under conditions that block endocytosis. The parasite can internalize by fluid-phase endocytosis macromolecules from the aqueous compartment surrounding it. Thus, surface antigens on trophozoites and schizonts should be considered as targets for antibody-directed parasiticidal agents.
C1 THOMAS JEFFERSON UNIV, JEFFERSON MED COLL, DEPT PATHOL & CELL BIOL, 1020 LOCUST ST, PHILADELPHIA, PA 19107 USA.
   DNAX RES INST MOLEC & CELLULAR BIOL INC, PALO ALTO, CA 94304 USA.
C3 Thomas Jefferson University; Merck & Company; Dnax Research Institute Of Molecular & Cellular Biology Inc.
NR 17
TC 198
Z9 210
U1 0
U2 4
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 73
EP 75
DI 10.1038/353073a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500061
PM 1715521
DA 2026-03-10
ER

PT J
AU WELLS, ML
   MAYER, LM
   DONARD, OFX
   SIERRA, MMD
   ACKELSON, SG
AF WELLS, ML
   MAYER, LM
   DONARD, OFX
   SIERRA, MMD
   ACKELSON, SG
TI THE PHOTOLYSIS OF COLLOIDAL IRON IN THE OCEANS
SO NATURE
LA English
DT Article
ID diatom thalassiosira-weissflogii; optical-property; natural-waters; phytoplankton
AB THE extent to which iron limits primary production in open ocean waters depends not only on the aeolian supply 1-3, but also on factors that control its availability for biological uptake. Although the marine chemistry of iron is poorly understood, much of it occurs in refractory particulate 1,2 and colloidal 4 states-forms unavailable for direct assimilation by phytoplankton 5,6. But iron availability depends on its chemical lability 5, or ease of dissolution; hence processes that alter the lability of particulate and colloidal iron in sea water govern their availability to phytoplankton. Here we report that light increases the lability of colloidal iron in sea water of pH 8, with a photon-normalized spectral dependence that generally increases with decreasing wavelength from 400-300 nm. From optical modelling we predict that the incident solar spectrum, combined with the preferential attenuation of shorter ultraviolet wavelengths in sea water, will lead to a maximum depth-integrated photoreaction near 380-400 nm. Our results show that the photolysis of forms of solid iron may occur deep into the ocean's euphotic zone, and hence that the availability of iron to phytoplankton in the ocean may be much greater than previously thought.
C1 UNIV MAINE, DARLING MARINE CTR, DEPT OCEANOG, WALPOLE, ME 04573 USA.
   UNIV BORDEAUX 1, PHOTOPHYS & PHOTOCHIM MOLEC LAB, F-33405 TALENCE, FRANCE.
   BIGELOW LAB OCEAN SCI, BOOTHBAY HARBOR, ME 04575 USA.
C3 University of Maine System; University of Maine Orono; Universite de Bordeaux; Bigelow Laboratory for Ocean Sciences
NR 20
TC 106
Z9 116
U1 0
U2 38
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 248
EP 250
DI 10.1038/353248a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400055
DA 2026-03-10
ER

PT J
AU PRIMMERMAN, CA
   MURPHY, DV
   PAGE, DA
   ZOLLARS, BG
   BARCLAY, HT
AF PRIMMERMAN, CA
   MURPHY, DV
   PAGE, DA
   ZOLLARS, BG
   BARCLAY, HT
TI COMPENSATION OF ATMOSPHERIC OPTICAL DISTORTION USING A SYNTHETIC BEACON
SO NATURE
LA English
DT Article
AB ATMOSPHERIC turbulence limits the resolution of a ground-based astronomical telescope to much worse than the diffraction limit of the instrument. An adaptive-optics system, in which some part of the optical train of the telescope can be adjusted in real time, can compensate for atmospheric turbulence, but a beacon or guide-star is needed to allow measurement of the atmospheric optical distortion. It has been suggested 1 that the measurement could be achieved by means of a synthetic beacon (also called an artificial beacon, and sometimes a laser guide-star) formed by atmospheric backscatter from a ground-based laser. We have performed an experiment to demonstrate atmospheric compensation using a synthetic beacon. With a pulsed dye laser to generate the beacon and a 241-channel adaptive-optics system to perform the phase correction, we obtained almost diffraction-limited resolution of star images in the visible part of the spectrum. Our results indicate that there are no technical barriers to atmospheric compensation using synthetic beacons at ground-based observatories.
RP PRIMMERMAN, CA (corresponding author), MIT,LINCOLN LAB,LEXINGTON,MA 02173, USA.
NR 7
TC 120
Z9 142
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 141
EP 143
DI 10.1038/353141a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100045
DA 2026-03-10
ER

PT J
AU DOTTI, CG
   PARTON, RG
   SIMONS, K
AF DOTTI, CG
   PARTON, RG
   SIMONS, K
TI POLARIZED SORTING OF GLYPIATED PROTEINS IN HIPPOCAMPAL-NEURONS
SO NATURE
LA English
DT Article
ID cells; culture
AB Our recent studies suggested that neurons and epithelial cells sort viral glycoproteins in a similar manner.  The apical influenza virus haemagglutinin was preferentially delivered to the axon of hippocampal neurons in culture, whereas the basolateral vesicular stomatitis virus glycoprotein was sorted to the dendrites. 1  To investigate whether other membrane proteins showed similar sorting in neurons and epithelial cells, we have analysed the localization of a glypiated (glycosylphosphatidylinositol-anchored) protein, Thy-1, in hippocampal neurons in culture.  In MDCk and other epithelial cells, endogenous glycosylphosphatidylinositol (GPI)-anchored proteins, as well as mutated exogenous proteins containing the GPI-attachment signal, undergo preferential delivery to the apical surface 2-4.  This polarized sorting of GPI-anchored proteins has been been proposed to occur by the same mechanisms as the sorting of glycolipids to the apical surface 5,6.  We report here that the neuronal GPI-protein Thy-1 is present in hippocampal neurons in culture and is exclusively located on the axonal surface.  This finding further strengthens our hypothesis that the mechanisms of sorting of surface components may be similar in neurons and epithelial cells.
RP DOTTI, CG (corresponding author), EUROPEAN MOLEC BIOL LAB,CELL BIOL PROGRAMME,MEYERHOFSTR 1,W-6900 HEIDELBERG,GERMANY.
NR 20
TC 220
Z9 226
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 158
EP 160
DI 10.1038/349158a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800059
PM 1670898
DA 2026-03-10
ER

PT J
AU WEISS, RF
   CARMACK, EC
   KOROPALOV, VM
AF WEISS, RF
   CARMACK, EC
   KOROPALOV, VM
TI DEEP-WATER RENEWAL AND BIOLOGICAL PRODUCTION IN LAKE BAIKAL
SO NATURE
LA English
DT Article
ID chlorofluoromethanes; seawater; ocean
AB The physics of mixing in deep temperate lakes is strongly constrained by the existence of a temperature of maximum density for fresh water, and by the pressure dependence of that temperature. The world's deepest lake is well suited to the study of such deep-water renewal processes, and also to the determination of the rate of renewal using time-dependent chemical tracers. The mean rates of biological recycling of oxygen, carbon and nutrients for the entire lake can then also be determined.
C1 FISHERIES & OCEANS CANADA INST OCEAN SCI, SIDNEY V8L 4B2, BC, CANADA.
   MOSCOW APPL GEOPHYS INST, MOSCOW 107258, USSR.
C3 Fisheries & Oceans Canada
RP WEISS, RF (corresponding author), UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, LA JOLLA, CA 92093 USA.
NR 27
TC 266
Z9 282
U1 2
U2 37
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 665
EP 669
DI 10.1038/349665a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700037
DA 2026-03-10
ER

PT J
AU RHEE, G
AF RHEE, G
TI AN ESTIMATE OF THE HUBBLE CONSTANT FROM THE GRAVITATIONAL LENSING OF QUASAR Q0957+561
SO NATURE
LA English
DT Article
ID galaxy
AB The double quasar Q0957 + 561 AB is believed to be a gravitationally lensed image formed by a galaxy at redshift z = 0.36:  a single quasar at z = 1.41 is seen as two images because of the intervening galaxy.  I present here a measurement of the velocity dispersion of the intervening galaxy which, combined with a measurement of the time delay between the appearance of brightness variations in the two images, can be applied to a simple model of the lensing geometry to yield an estimate for the Hubble constant H0.  The flux from the A and B images has been monitored for several years by two groups and a consistent value of 415 days for the time delay between variations in A and B has been obtained.  The measured line-of-sight velocity dispersion for the intervening galaxy of 303 +/- 50 km s-1 then gives H0 = 50 +/- 17 km s-1 Mpc-1.
C1 STERREWACHT LEIDEN,2300 RA LEIDEN,NETHERLANDS.
C3 Leiden University; Leiden University - Excl LUMC
NR 14
TC 59
Z9 60
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 211
EP 212
DI 10.1038/350211a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900048
DA 2026-03-10
ER

PT J
AU THORSETT, SE
   NICE, DJ
AF THORSETT, SE
   NICE, DJ
TI ECLIPSES OF THE ABLATING BINARY PULSAR PSR1744-24A
SO NATURE
LA English
DT Article
ID x-ray binary; millisecond pulsar; terzan-5
AB PSR1744-24A, a binary pulsar in the globular cluster Terzan 5, is eclipsed for up to half of each 109-minute orbit 1,2. This is a much longer duration than its 0.09-solar-mass companion star could cause if it were confined within its Roche lobe, and has led to the suggestion that PSR1744-24A is ablating material from its companion, producing an extensive stellar wind that eclipses the radio signal. We have measured the pulsar light curve at a frequency of 1.67 GHz, and find that the eclipse is not total: maximum attenuation in some cases is only about 70 per cent. The pulsar signal is substantially delayed during the eclipse. We model these observations by means of free-free absorption and dispersion in an ionized wind, processes which also explain the frequency dependence of the eclipse duration 3.  A simplified model predicts a wind density at the Roche surface of approximately 6 X 10(7) electrons cm-3 and an electron temperature in the wind of (3.6-15) x 10(3) K, although some theoretical difficulties remain. Such a wind is unlikely to ablate the companion star entirely in less than a Hubble time, so that in this one case at least, ablation may not ultimately form an isolated millisecond pulsar.
C1 PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544.
   PRINCETON UNIV,JOSEPH HENRY LABS,PRINCETON,NJ 08544.
C3 Princeton University; Princeton University
NR 11
TC 12
Z9 12
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 731
EP 733
DI 10.1038/353731a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600059
DA 2026-03-10
ER

PT J
AU TAYLOR, SJ
   CHAE, HZ
   RHEE, SG
   EXTON, JH
AF TAYLOR, SJ
   CHAE, HZ
   RHEE, SG
   EXTON, JH
TI ACTIVATION OF THE BETA-1 ISOZYME OF PHOSPHOLIPASE-C BY ALPHA-SUBUNITS OF THE GQ CLASS OF G-PROTEINS
SO NATURE
LA English
DT Article
ID bovine brain; tyrosine phosphorylation
AB MANY hormones, neurotransmitters and growth factors, on binding to G protein-coupled receptors or receptors possessing tyrosine kinase activity, increase intracellular levels of the second messengers inositol 1,4,5-trisphophate and 1,2-diacylglycerol. This is due to activation of phosphoinositide-specific phospholipase(s) C (PLC), the isozymes of which are classified into groups, alpha, beta, gamma and delta (refs 1, 2). The beta, gamma and delta-groups themselves contain PLC isozymes which have both common and unique structural domains 3. Only the gamma-1 isozyme has been implicated in a signal transduction mechanism 4. This involves association with, and tyrosine phosphorylation by, the ligand-bound epidermal growth factor and platelet-derived growth factor receptors 5-7, probably by means of the PLC-gamma-1-specific src homology (SH2) domain 8. Because EGF receptor-mediated tyrosine phosphorylation of PLC-gamma-1 stimulates catalytic activity in vitro 9 and G proteins have been implicated in the activation of PLC 10, we investigated which PLC isozymes are subject to G protein regulation. We have purified 11 an activated G protein alpha-subunit that stimulates partially purified phospholipase C and now report that this G protein specifically activates the beta-1 isozyme, but not the gamma-1 and delta-1 isozymes of phospholipase C. We also show that this protein is related to the G(q) class of G protein alpha-subunits 12.
C1 VANDERBILT UNIV, MED CTR,SCH MED,HOWARD HUGHES MED INST, DEPT MOLEC PHYSIOL & BIOPHYS, NASHVILLE, TN 37232 USA.
   NHLBI, BIOCHEM LAB, BETHESDA, MD 20892 USA.
C3 Vanderbilt University; Howard Hughes Medical Institute; National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI)
NR 30
TC 775
Z9 830
U1 0
U2 7
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 516
EP 518
DI 10.1038/350516a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300056
PM 1707501
DA 2026-03-10
ER

PT J
AU GOATE, A
   CHARTIERHARLIN, MC
   MULLAN, M
   BROWN, J
   CRAWFORD, F
   FIDANI, L
   GIUFFRA, L
   HAYNES, A
   IRVING, N
   JAMES, L
   MANT, R
   NEWTON, P
   ROOKE, K
   ROQUES, P
   TALBOT, C
   PERICAKVANCE, M
   ROSES, A
   WILLIAMSON, R
   ROSSOR, M
   OWEN, M
   HARDY, J
AF GOATE, A
   CHARTIERHARLIN, MC
   MULLAN, M
   BROWN, J
   CRAWFORD, F
   FIDANI, L
   GIUFFRA, L
   HAYNES, A
   IRVING, N
   JAMES, L
   MANT, R
   NEWTON, P
   ROOKE, K
   ROQUES, P
   TALBOT, C
   PERICAKVANCE, M
   ROSES, A
   WILLIAMSON, R
   ROSSOR, M
   OWEN, M
   HARDY, J
TI SEGREGATION OF A MISSENSE MUTATION IN THE AMYLOID PRECURSOR PROTEIN GENE WITH FAMILIAL ALZHEIMERS-DISEASE
SO NATURE
LA English
DT Article
ID secondary structure; linkage; chromosome-21; cdna; prediction; markers; defect; locus; dna
AB A LOCUS segregating with familial Alzheimer's disease (AD) has been mapped to chromosome 21 (ref. 1), close to the amyloid precursor protein (APP) gene 2-5. Recombinants between the APP gene and the AD locus have been reported 6-8 which seemed to exclude it as the site of the mutation causing familial AD. But recent genetic analysis of a large number of AD families has demonstrated that the disease is heterogeneous 9. Families with late-onset AD do not show linkage to chromosome 21 markers 9,10. Some families with early-onset AD show linkage to chromosome 21 markers, but some do not 8,9,11. This has led to the suggestion that there is non-allelic genetic heterogeneity even within early onset familial AD 8,9. To avoid problems that heterogeneity poses for genetic analysis, we have examined the cosegregation of AD and markers along the long arm of chromosome 21 in a single family with AD confirmed by autopsy. Here we demonstrate that in this kindred, which shows linkage to chromosome 21 markers, there is a point mutation in the APP gene. This mutation causes an amino-acid substitution (Val --> Ile) close to the carboxy terminus of the beta-amyloid peptide. Screening other cases of familial AD revealed a second unrelated family in which this variant occurs. This suggests that some cases of AD could be caused by mutations in the APP gene.
C1 ST MARYS HOSP, SCH MED, DEPT BIOCHEM, ALZHEIMERS DIS RES GRP, LONDON W2 1PG, ENGLAND.
   ST MARYS HOSP, SCH MED, DEPT NEUROL, LONDON W2 1PG, ENGLAND.
   YALE UNIV, SCH MED, DEPT HUMAN GENET, NEW HAVEN, CT 06510 USA.
   DUKE UNIV, MED CTR, DURHAM, NC 27710 USA.
   UNIV COLL CARDIFF, DEPT PSYCHOL MED, CARDIFF CF4 4XN, S GLAM, WALES.
   UNIV COLL CARDIFF, DEPT MED GENET, CARDIFF CF4 4XN, S GLAM, WALES.
C3 Imperial College London; Imperial College London; Yale University; Duke University; Cardiff University; Cardiff University
FU NIA NIH HHS [AG-05128] Funding Source: Medline; Wellcome Trust Funding Source: Medline
NR 30
TC 3949
Z9 4654
U1 1
U2 539
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 704
EP 706
DI 10.1038/349704a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700050
PM 1671712
DA 2026-03-10
ER

PT J
AU BROCHIER, B
   KIENY, MP
   COSTY, F
   COPPENS, P
   BAUDUIN, B
   LECOCQ, JP
   LANGUET, B
   CHAPPUIS, G
   DESMETTRE, P
   AFIADEMANYO, K
   LIBOIS, R
   PASTORET, PP
AF BROCHIER, B
   KIENY, MP
   COSTY, F
   COPPENS, P
   BAUDUIN, B
   LECOCQ, JP
   LANGUET, B
   CHAPPUIS, G
   DESMETTRE, P
   AFIADEMANYO, K
   LIBOIS, R
   PASTORET, PP
TI LARGE-SCALE ERADICATION OF RABIES USING RECOMBINANT VACCINIA RABIES VACCINE
SO NATURE
LA English
DT Article
ID oral vaccination; field trial; virus glycoprotein; fox raby; immunization; wildlife; protection; expression; efficacy; safety
AB RABIES infection of domestic and wild animals is a serious problem throughout the world. The major disease vector in Europe is the red fox (Vulpes vulpes) and rabies control has focused on vaccinating and/or culling foxes. Culling has not been effective, and the distribution of live vaccine baits is the only appropriate method for the vaccination of wild foxes 1.  Although some European countries have conducted field vaccination campaigns using attenuated rabies virus strains 2-5, their use has not been extensively approved because they retain pathogenicity for rodents and can revert to virulence 6,7.  These strains cannot be used in North America because they are pathogenic for the striped skunk (Mephitis mephitis) 8 and are ineffective in the racoon (Procyon lotor) 9.  We have constructed a recombinant vaccinia virus 10, VVTGgRAB, expressing the surface glycoprotein (G) of rabies virus (ERA strain) 11-13.  The recombinant was a highly effective vaccine in experimental animals 11-13, in captive foxes 14,15 and in racoons 9.  We report here the results of a large-scale campaign of fox vaccination in a 2,200 km2 region of southern Belgium, an area in which rabies is prevalent. After distribution, 81% of foxes inspected were positive for tetracycline, a biomarker included in the vaccine bait and, other than one rabid fox detected close to the periphery of the treated area, no case of rabies, either in foxes or in domestic livestock, has been reported in the area.
C1 TRANSGENE SA,F-67000 STRASBOURG,FRANCE.
   PASTEUR INST BRABANT,DEPT RABIES,B-1180 BRUSSELS,BELGIUM.
   RHONE MERIEUX LAB IFFA,F-69342 LYONS,FRANCE.
   STATE UNIV LIEGE,FAC SCI,INST ZOOL,B-4020 LIEGE,BELGIUM.
C3 Transgene SA; University of Liege
RP BROCHIER, B (corresponding author), STATE UNIV LIEGE,FAC VET MED,DEPT VIROL,45 RUE VET,B-1070 BRUSSELS,BELGIUM.
NR 31
TC 226
Z9 263
U1 1
U2 67
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 520
EP 522
DI 10.1038/354520a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100013
PM 1758494
DA 2026-03-10
ER

PT J
AU BLAKELY, RD
   BERSON, HE
   FREMEAU, RT
   CARON, MG
   PEEK, MM
   PRINCE, HK
   BRADLEY, CC
AF BLAKELY, RD
   BERSON, HE
   FREMEAU, RT
   CARON, MG
   PEEK, MM
   PRINCE, HK
   BRADLEY, CC
TI CLONING AND EXPRESSION OF A FUNCTIONAL SEROTONIN TRANSPORTER FROM RAT-BRAIN
SO NATURE
LA English
DT Article
ID imipramine binding-sites; tritiated imipramine; depressed-patients; uptake inhibitor; gaba transporter; ligand-binding; polymerase; platelets; dopamine; protein
AB SELECTIVE antagonism of serotonin (5-hydroxytryptamine, 5HT) and noradrenaline transport by antidepressants is a key element in the 'amine' hypothesis of affective disorders 1. Uptake 2,3 and/or transport sites 4-5 of 5HT have been reported to be reduced in platelets of patients suffering from depression and in post-mortem brain samples of depressed patients 6 and suicide victims 7. To date there has been little molecular information available on the structure and regulation of 5HT transporters. Using the polymerase chain reaction 8 with degenerate oligonucleotides 9 derived from two highly conserved regions of the transporters for noradrenaline 10 and gamma-aminobutyric acid 11 (GABA), we have identified a large family of related gene products expressed in rodent brain. One of these products hybridizes to a single 3.7-kilobase RNA restricted to rat midbrain and brainstem, where it is highly enriched within the serotonergic raphe complex. Transfection with a single 2.3-kilobase brainstem complementary DNA clone is sufficient to confer expression of a Na+-dependent 5HT transporter upon non-neural cells, with transport selectively and potently antagonized by 5HT uptake-specific antidepressants, including paroxetine, citalopram and fluoxetine.
C1 EMORY UNIV, SCH MED, PROGRAM NEUROSCI, ATLANTA, GA 30322 USA.
   DUKE UNIV, SCH MED, DEPT NEUROBIOL, DURHAM, NC 27710 USA.
   DUKE UNIV, SCH MED, DEPT CELL BIOL & MED, DURHAM, NC 27710 USA.
C3 Emory University; Duke University; Duke University
RP BLAKELY, RD (corresponding author), EMORY UNIV, SCH MED, DEPT ANAT & CELL BIOL, ATLANTA, GA 30322 USA.
NR 39
TC 728
Z9 807
U1 0
U2 28
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 66
EP 70
DI 10.1038/354066a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900059
PM 1944572
DA 2026-03-10
ER

PT J
AU PRODEHL, C
   MECHIE, J
   KAMINSKI, W
   FUCHS, K
   GROSSE, C
   HOFFMANN, H
   STANGL, R
   STELLRECHT, R
   KHAN, MA
   MAGUIRE, PKH
   KIRK, W
   KELLER, GR
   GITHUI, A
   BAKER, M
   MOONEY, W
   CRILEY, E
   LUETGERT, J
   JACOB, B
   THYBO, H
   DEMARTIN, M
   SCARASCIA, S
   HIRN, A
   BOWMAN, JR
   NYAMBOK, I
   GACIRI, S
   PATEL, J
   DINDI, E
   GRIFFITHS, DH
   KING, RF
   MUSSETT, AE
   BRAILE, LW
   THOMPSON, G
   OLSEN, K
   HARDER, S
   VEES, R
   GAJEWSKI, D
   SCHULTE, A
   OBEL, J
   MWANGO, F
   MUKINYA, J
   RIAROH, D
AF PRODEHL, C
   MECHIE, J
   KAMINSKI, W
   FUCHS, K
   GROSSE, C
   HOFFMANN, H
   STANGL, R
   STELLRECHT, R
   KHAN, MA
   MAGUIRE, PKH
   KIRK, W
   KELLER, GR
   GITHUI, A
   BAKER, M
   MOONEY, W
   CRILEY, E
   LUETGERT, J
   JACOB, B
   THYBO, H
   DEMARTIN, M
   SCARASCIA, S
   HIRN, A
   BOWMAN, JR
   NYAMBOK, I
   GACIRI, S
   PATEL, J
   DINDI, E
   GRIFFITHS, DH
   KING, RF
   MUSSETT, AE
   BRAILE, LW
   THOMPSON, G
   OLSEN, K
   HARDER, S
   VEES, R
   GAJEWSKI, D
   SCHULTE, A
   OBEL, J
   MWANGO, F
   MUKINYA, J
   RIAROH, D
TI LARGE-SCALE VARIATION IN LITHOSPHERIC STRUCTURE ALONG AND ACROSS THE KENYA RIFT
SO NATURE
LA English
DT Article
ID gregory rift; valley
AB THE Kenya rift is one of the classic examples of a continental rift zone:  models for its evolution range from extension of the lithosphere by pure shear 1, through extension by simple shear 2, to diapiric upwelling of an asthenolith 3.  Following a pilot study in 1985 4, the present work involved the shooting of three seismic refraction and wide-angle reflection profiles along the axis, across the margins, and on the northeastern flank of the rift (Fig. 1). These lines were intended to reconcile the different crustal thickness estimates for the northern and southern parts of the rift 4-6 and to reveal the structure across the rift, including that beneath the Hanks. The data, presented here, reveal significant lateral variations in structure both along and across the rift. The crust thins along the rift axis from 35 km in the south to 20 km in the north; there are abrupt changes in Moho depth and uppermost-mantle seismic velocity across the rift margins, and crustal thickening across the boundary between the Archaean craton and Pan-African orogenic belt immediately west of the rift. These results suggest that thickened crust may have controlled the rift's location, that there is a decrease in extension from north to south, and that the upper mantle immediately beneath the rift may contain reservoirs of magma generated at greater depth.
C1 UNIV LEICESTER,DEPT GEOG,LEICESTER LE1 7RH,ENGLAND.
   UNIV TEXAS,DEPT GEOL SCI,EL PASO,TX 79968.
   US GEOL SURVEY,MENLO PK,CA 94025.
   UNIV COPENHAGEN,INST ALMEN GEOL,COPENHAGEN,DENMARK.
   CNR,IST GEOFIS LITOSFERA,I-20133 MILAN,ITALY.
   INST PHYS GLOBE,PARIS,FRANCE.
   AUSTRALIAN NATL UNIV,SCH EARTH SCI,CANBERRA,ACT 2600,AUSTRALIA.
   UNIV NAIROBI,NAIROBI,KENYA.
   UNIV BIRMINGHAM,DEPT GEOL SCI,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND.
   UNIV LIVERPOOL,DEPT GEOL SCI,LIVERPOOL L69 3BX,ENGLAND.
   PURDUE UNIV,DEPT EARTH & ATMOSPHERE SCI,W LAFAYETTE,IN 47907.
   STANFORD UNIV,MENLO PK,CA 94025.
   UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544.
   TEXAS A&M UNIV SYST,COLLEGE STN,TX 77843.
   UNIV CLAUSTHAL,INST GEOPHYS,CLAUSTHAL ZELLERFE,GERMANY.
   SURVEY KENYA,NAIROBI,KENYA.
   MINIST WATER RESOURCES & DEV,NAIROBI,KENYA.
   DEPT FISHERIES,NAIROBI,KENYA.
   MINIST ENERGY,NAIROBI,KENYA.
C3 University of Leicester; University of Texas System; University of Texas El Paso; United States Department of the Interior; United States Geological Survey; University of Copenhagen; Consiglio Nazionale delle Ricerche (CNR); Universite Paris Cite; Australian National University; University of Nairobi; University of Birmingham; University of Liverpool; Purdue University System; Purdue University; Stanford University; United States Department of Energy (DOE); Los Alamos National Laboratory; Texas A&M University System; Texas A&M University College Station; TU Clausthal
RP PRODEHL, C (corresponding author), UNIV KARLSRUHE,INST GEOPHYS,W-7500 KARLSRUHE,GERMANY.
NR 19
TC 60
Z9 63
U1 0
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 223
EP 227
DI 
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800047
DA 2026-03-10
ER

PT J
AU WERNER, P
   VOIGT, M
   KEINANEN, K
   WISDEN, W
   SEEBURG, PH
AF WERNER, P
   VOIGT, M
   KEINANEN, K
   WISDEN, W
   SEEBURG, PH
TI CLONING OF A PUTATIVE HIGH-AFFINITY KAINATE RECEPTOR EXPRESSED PREDOMINANTLY IN HIPPOCAMPAL CA3 CELLS
SO NATURE
LA English
DT Article
ID acid binding-sites; kainic acid; glutamate receptor; nervous-system; rat forebrain; localization; subunit; brain; sequence; family
AB KAINIC acid is a potent neurotoxin for certain neurons 1.  Its neurotoxicity is thought to be mediated by an excitatory amino-acid-gated ion channel (ionotropic receptor) possessing nanomolar affinity for kainate 2. Here we describe a new member of the rat excitatory amino-acid receptor gene family, KA-1, that has a 30% sequence similarity with the previously characterized alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor subunits GluR-A to -D 3-5.  The pharmacological profile of expressed recombinant KA-1 determined in binding experiments with [H-3]kainate is different from that of the cloned AMPA receptors and similar to the mammalian high-affinity kainate receptor (kainate > quisqualate > glutamate >> AMPA) with a dissociation constant of about 5 nM for kainate 2,6.  The selectively high expression of KA-1 messenger RNA in the CA3 region of the hippocampus closely corresponds to autoradiographically located high-affinity kainate binding sites 7-9.  This correlation, as well as the particular in vivo pattern of neurodegeneration observed on kainate-induced neurotoxicity 1,2, suggests that KA participates in receptors mediating the kainate sensitivity of neurons in the central nervous system.
C1 UNIV HEIDELBERG,CTR MOLEC BIOL,MOLEC NEUROENDOCRINOL LAB,NEUENHEIMER FELD 282,W-6900 HEIDELBERG,GERMANY.
C3 Ruprecht Karls University Heidelberg
NR 30
TC 449
Z9 498
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 742
EP 744
DI 10.1038/351742a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100063
PM 1648176
DA 2026-03-10
ER

PT J
AU SUMIMOTO, H
   OHKUMA, Y
   SINN, E
   KATO, H
   SHIMASAKI, S
   HORIKOSHI, M
   ROEDER, RG
AF SUMIMOTO, H
   OHKUMA, Y
   SINN, E
   KATO, H
   SHIMASAKI, S
   HORIKOSHI, M
   ROEDER, RG
TI CONSERVED SEQUENCE MOTIFS IN THE SMALL SUBUNIT OF HUMAN GENERAL TRANSCRIPTION FACTOR TFIIE
SO NATURE
LA English
DT Article
ID rna polymerase-ii; sigma-factors; initiation; proteins; purification; specificity; expression; binding; myod
AB A GENERAL initiation factor, TFIIE, is essential for transcription initiation by RNA polymerase II in conjunction with other general factors 1,2 . TFIIE is a heterotetramer containing two subunits of relative molecular mass 57,000 (TFIIE-alpha) and two of 34,000 (TFIIE-beta) 3,4. TFIIE-beta is required in conjunction with TFIIE-alpha for transcription initiation. Here we report the cloning and expression of a complementary DNA encoding a functional human TFIIE-beta. Recombinant TFIIE-beta could replace the natural TFIIE-beta for transcription in conjunction with TFIIE-alpha. Amino-acid sequence comparisons reveal regions with sequence similarities to: subregion 3 of bacterial or factors 6; a region of RAP30 (the small subunit of TFIIF) with sequence similarity to a sigma-factor subregion implicated in binding to RNA polymerase 7; and a portion of the basic region-helix-loop-helix motif found in several enhancer-binding proteins 8-10. These potential homologies have implications for the role of TFIIE in preinitiation complex assembly and function.
C1 WHITTIER INST DIABET & ENDOCRINOL,DEPT MOLEC ENDOCRINOL,LA JOLLA,CA 92037.
RP SUMIMOTO, H (corresponding author), ROCKEFELLER UNIV,BIOCHEM & MOLEC BIOL LAB,NEW YORK,NY 10021, USA.
NR 30
TC 80
Z9 84
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 401
EP 404
DI 10.1038/354401a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100054
PM 1956404
DA 2026-03-10
ER

PT J
AU CLUTTONBROCK, TH
   VINCENT, ACJ
AF CLUTTONBROCK, TH
   VINCENT, ACJ
TI SEXUAL SELECTION AND THE POTENTIAL REPRODUCTIVE RATES OF MALES AND FEMALES
SO NATURE
LA English
DT Article
ID breeding-behavior; parental investment; pimephales-promelas; spring emergence; mating systems; fathead minnow; mate choice; success; pisces; care
AB PRONOUNCED sex differences in mating competition are a prominent feature of many animal breeding systems. These differences are widely attributed to sex differences in parental investment 1,2 which bias the ratio of sexually receptive females to males 3 (the operational sex ratio), generating more intense competition between members of one sex, usually males 3-5. Unfortunately, relative parental investment 1 is usually impossible to measure in species where both sexes invest in their offspring 6,7 and there is currently no empirical basis for predicting the pattern of mating competition in these species. In contrast, the potential rate of reproduction by males and females (measured as the maximum number of independent offspring that parents can produce per unit time) is both more directly related to the operational sex ratio and more easily estimated in natural populations 7. Here we show that among species where males care for the young, the sex with the higher potential reproductive rate competes more intensely for mates than the sex with the lower potential rate of reproduction.
RP CLUTTONBROCK, TH (corresponding author), UNIV CAMBRIDGE, DEPT ZOOL, LARGE ANIM RES GRP, CAMBRIDGE CB3 0DT, ENGLAND.
NR 71
TC 593
Z9 687
U1 2
U2 232
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 58
EP 60
DI 
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300058
PM 2027382
DA 2026-03-10
ER

PT J
AU BRESSAC, B
   KEW, M
   WANDS, J
   OZTURK, M
AF BRESSAC, B
   KEW, M
   WANDS, J
   OZTURK, M
TI SELECTIVE G-MUTATION TO T-MUTATION OF P53 GENE IN HEPATOCELLULAR-CARCINOMA FROM SOUTHERN AFRICA
SO NATURE
LA English
DT Article
ID hepatitis-b virus; cell-line; liver; dna; establishment
AB HEPATOCELLULAR carcinoma (HCC) is a prevalent cancer in sub-Saharan Africa and eastern Asia 1.  Hepatitis B virus and aflatoxins are risk factors for HCC 2, but the molecular mechanism of human hepatocellular carcinogenesis is largely unknown 3.  Abnormalities in the structure and expression of the tumour-suppressor gene p53 are frequent in HCC cell lines 4, and allelic losses from chromosome 17p have been found in HCCs from China 5 and Japan 6.  Here we report on allelic deletions from chromosome 17p and mutations of the p53 gene found in 50% of primary HCCs from southern Africa.  Four of five mutations detected were G --> T substitutions, with clustering at codon 249.  This mutation specificity could reflect exposure to a specific carcinogen, one candidate being aflatoxin B1 (ref. 7), a food contaminant in Africa 8, which is both a mutagen that induces G to T substitution 9 and a liver-specific carcinogen 10.
C1 MASSACHUSETTS GEN HOSP,CTR CANC,MOLEC HEPATOL LAB,MGH E,149 13TH ST,BOSTON,MA 02129.
   UNIV WITWATERSRAND,PARKTOWN 2193,SOUTH AFRICA.
C3 Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; University of Witwatersrand
NR 29
TC 1295
Z9 1406
U1 0
U2 78
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 429
EP 431
DI 10.1038/350429a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200052
PM 1672732
DA 2026-03-10
ER

PT J
AU SMITH, WO
   CODISPOTI, LA
   NELSON, DM
   MANLEY, T
   BUSKEY, EJ
   NIEBAUER, HJ
   COTA, GF
AF SMITH, WO
   CODISPOTI, LA
   NELSON, DM
   MANLEY, T
   BUSKEY, EJ
   NIEBAUER, HJ
   COTA, GF
TI IMPORTANCE OF PHAEOCYSTIS BLOOMS IN THE HIGH-LATITUDE OCEAN CARBON-CYCLE
SO NATURE
LA English
DT Article
ID marginal ice-zone; sea; pouchetii; autumn
AB THE Greenland Sea is particularly important to the world ocean circulation, and potentially to carbon dioxide exchange between the ocean and atmosphere, because it is an area of surface convergence and deep-water formation 1-3.  Previous investigations indicate that biological productivity is low 4,5 in this area, especially in waters remote from the ice edge. During April and early May 1989, however, we observed the development of a massive bloom of the colonial prymnesiophyte Phaeocystis pouchetii across much of the Greenland Sea. From measurements of the rate of removal of nitrate from surface waters, we calculate that the average regional new production was about 40 g C m-2 during the 35-day period of our observations. This rate of new production is approximately equal to that observed in other hyperproductive polar regions, such as the Bering Sea and the Bransfield Strait. Because Phaeocystis blooms seem to be frequent and widespread in polar ocean 4,6, our results suggest that the Greenland Sea may be a larger sink of atmospheric carbon dioxide than has been previously thought.
C1 MONTEREY BAY AQUARIUM,RES INST,PACIFIC GROVE,CA 93950.
   UNIV ALASKA,INST MARINE SCI,FAIRBANKS,AK 99775.
   UNIV TENNESSEE,GRAD PROGRAM ECOL,KNOXVILLE,TN 37996.
   OREGON STATE UNIV,COLL OCEANOG,CORVALLIS,OR 97331.
   MIDDLEBURY COLL,DEPT GEOL,MIDDLEBURY,VT 05753.
   UNIV TEXAS,DEPT OCEANOG,PORT ARANSAS,TX 78373.
C3 Monterey Bay Aquarium Research Institute; University of Alaska System; University of Alaska Fairbanks; University of Tennessee System; University of Tennessee Knoxville; Oregon State University; Middlebury College; University of Texas System
RP SMITH, WO (corresponding author), UNIV TENNESSEE,DEPT BOT,KNOXVILLE,TN 37996, USA.
NR 29
TC 146
Z9 162
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 514
EP 516
DI 10.1038/352514a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600057
DA 2026-03-10
ER

PT J
AU WALKER, DH
   MALLER, JL
AF WALKER, DH
   MALLER, JL
TI ROLE FOR CYCLIN-A IN THE DEPENDENCE OF MITOSIS ON COMPLETION OF DNA-REPLICATION
SO NATURE
LA English
DT Article
ID maturation-promoting factor; embryonic-cell cycle; messenger-rna; xenopus oocytes; protein; initiation; eggs; degradation; extracts; entry
AB THE cyclins were first identified by their cell-cycle-dependent synthesis and destruction 1-3 and have a key role in the control of mitosis in Xenopus embryonic cell cycles 4-6. All higher eukaryotes have at least two types of cyclins, the A- and B-type, which can be distinguished by sequence motifs and the timing of their destruction in the cell cycle 2,7-10. The degradation of both cyclins is required for exit from mitosis 11, but the activation and destruction of cyclin A occur earlier in the cell cycle than with the B-type cyclins 9-11. This suggests that cyclin A has a distinct role in cell-cycle progression. We have used an antisense oligodeoxynucleotide directed against cyclin A to investigate this role. Ablation of cyclin A messenger RNA in cytostatic factor/metaphase-arrested extracts of Xenopus eggs, followed by in vitro progression into interphase, resulted in the premature appearance of cyclin B/cdc2-associated H1 kinase activity and premature entry into mitosis. Although cyclin A-ablated extracts could initiate DNA synthesis during interphase, S phase was not completed before entry into mitosis. The effects of cyclin A ablation were reversed by the addition of cyclin A mRNA or cyclin A protein to the extracts.
RP WALKER, DH (corresponding author), UNIV COLORADO,SCH MED,HOWARD HUGHES MED INST,DENVER,CO 80262, USA.
NR 28
TC 205
Z9 253
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 314
EP 317
DI 10.1038/354314a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400050
PM 1659666
DA 2026-03-10
ER

PT J
AU FERREN, RA
AF FERREN, RA
TI ADVANCES IN POLYMERIC PIEZOELECTRIC TRANSDUCERS
SO NATURE
LA English
DT Article
RP FERREN, RA (corresponding author), ATOCHEM SENSORS INC,950 FORGE AVE,NORRISTOWN,PA 19403, USA.
NR 0
TC 7
Z9 10
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 26
EP 27
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100009
DA 2026-03-10
ER

PT J
AU SIVELL, WJ
   MCCULLOCH, MT
AF SIVELL, WJ
   MCCULLOCH, MT
TI NEODYMIUM ISOTOPE EVIDENCE FOR ULTRA-DEPLETED MANTLE IN THE EARLY PROTEROZOIC
SO NATURE
LA English
DT Article
ID 1.9-1.7 ga age; continental-crust; central australia; trace-element; nd isotopes; evolution; basalts; range; arc; sr
AB THE episodic extraction of juvenile continental crust from the Earth's mantle over the past 4 Gyr has led to a progressive depletion of incompatible elements in the upper mantle 1,2. A knowledge of the degree and uniformity of this mantle depletion throughout Earth history is important for understanding the growth of continents, the evolution of the crust-mantle system and the nature of mantle convection through time. Here we report initial Nd-143/Nd-144 ratios for 1.8-Gyr-old mafic volcanics from the Harts Range meta-igneous complex of central Australia which are the highest yet reported for Proterozoic igneous rocks (epsilon(Nd) = +6.9 to +8.2 for the least contaminated samples). These ratios far exceed those proposed in models 3-5 for the isotopic evolution of the depleted mantle at this time, and imply the existence of a mantle reservoir that had been highly depleted for at least 1 Gyr. This provides strong evidence that major periods of continental growth, such as that in the late Archaean, produced long-lived heterogeneities in the upper mantle.
C1 AUSTRALIAN NATL UNIV,RES SCH EARTH SCI,CANBERRA,ACT 2601,AUSTRALIA.
C3 Australian National University
RP SIVELL, WJ (corresponding author), UNIV WESTERN SYDNEY,FAC SCI & TECHNOL,KINGSWOOD 2747,AUSTRALIA.
NR 31
TC 22
Z9 24
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 384
EP 387
DI 10.1038/354384a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100048
DA 2026-03-10
ER

PT J
AU ZHOU, O
   FISCHER, JE
   COUSTEL, N
   KYCIA, S
   ZHU, Q
   MCGHIE, AR
   ROMANOW, WJ
   MCCAULEY, JP
   SMITH, AB
   COX, DE
AF ZHOU, O
   FISCHER, JE
   COUSTEL, N
   KYCIA, S
   ZHU, Q
   MCGHIE, AR
   ROMANOW, WJ
   MCCAULEY, JP
   SMITH, AB
   COX, DE
TI STRUCTURE AND BONDING IN ALKALI-METAL-DOPED C60
SO NATURE
LA English
DT Article
ID graphite; c-60
AB IT has been shown recently that M(x)C60 (M = alkali metal) is metallic at 300 K for some M and x (ref. 1) and superconducts below 18 K for M = potassium 2. These observations give further impetus to studies of the molecular 3 and solid-state 4 properties of fullerenes. Here we report on X-ray diffraction studies of the structure and bonding in alkali-metal-doped solid C60 (fullerite). Powder diffraction data obtained from equilibrium compositions of C60 doped to saturation with K or Cs show that the face-centred cubic lattice of pure C60 (refs 5-7) transforms to body-centred cubic at these doping levels, with a saturation composition close to M6C60. The rotational disorder of the fullerene molecules in pure C60 at 300 K is absent in the fully doped compounds.
C1 UNIV PENN, RES STRUCT MATTER LAB, PHILADELPHIA, PA 19104 USA.
C3 University of Pennsylvania
NR 18
TC 347
Z9 367
U1 1
U2 70
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 462
EP 464
DI 10.1038/351462a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800048
DA 2026-03-10
ER

PT J
AU SWAT, W
   IGNATOWICZ, L
   VONBOEHMER, H
   KISIELOW, P
AF SWAT, W
   IGNATOWICZ, L
   VONBOEHMER, H
   KISIELOW, P
TI CLONAL DELETION OF IMMATURE CD4+8+ THYMOCYTES IN SUSPENSION-CULTURE BY EXTRATHYMIC ANTIGEN-PRESENTING CELLS
SO NATURE
LA English
DT Article
ID transgenic mice; t-cells; tolerance; receptor; thymus
AB ONE mechanism ensuring self tolerance of T cells is the clonal deletion of thymocytes bearing alpha-beta T-cell receptors 1-4.  The stage of thymocyte development at which the interaction with antigen-presenting cells (APCs) leads to deletion, however, has not been determined directly.  Indirect evidence suggests that intrathymic APCs induce deletion of CD4+8+ thymocytes 3-6 (which die by apoptosis 7) but deletion at less 8 and more mature 9 developmental stages has also been implied.  It is also not clear if clonal elimination of thymocytes can be triggered by peripheral antigens carried on extrathymic APCs migrating through the thymus 10.  Here we show antigen-specific induction of apoptosis in CD4+8+ thymocytes cultured in suspension, by thymic as well as splenic APCs.  Thus the recognition of antigen by CD4+8+ thymocytes may lead to deletion, suggesting that this is the central mechanism of tolerance induction, which is not limited by the antigen-presenting ability of the thymic stroma.
C1 POLISH ACAD SCI,INST IMMUNOL & EXPTL THERAPY,UL CZERSKA 12,PL-53114 WROCLAW,POLAND.
   BASEL INST IMMUNOL,CH-4005 BASEL,SWITZERLAND.
C3 Polish Academy of Sciences; Hirszfeld Institute of Immunology & Experimental Therapy of the Polish Academy of Sciences
NR 18
TC 272
Z9 286
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 150
EP 153
DI 10.1038/351150a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500052
PM 1903182
DA 2026-03-10
ER

PT J
AU SASLAW, WC
AF SASLAW, WC
TI BLACK-HOLES AND STRUCTURE IN AN OSCILLATING UNIVERSE
SO NATURE
LA English
DT Article
ID pregalactic objects; galaxy
AB IF black holes exist in the contracting phase of a closed universe, they will give rise to a pressure and entropy catastrophe.  First, the black holes absorb all the radiation; then their apparent horizons merge, and coalesce with the cosmological apparent horizon.  All external observers become internal observers.  It is possible that the internal metric of some of the merging black holes will be contracting, and others expanding.  I suggest here that the resulting violent inhomogeneities can lead to a re-expansion in a significant portion of the universe. Global re-expansion, prompted by the merging of black holes, may thus begin in a semi-classical rather than fully quantum gravitational era, at densities greater than those at which nucleosynthesis occurs. Surviving black holes and inhomogeneities could initiate the formation of structures such as galaxies in the 'new' universe.  The behaviour of such an oscillating universe would differ in detail from cycle to cycle.
C1 UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND.
   NATL RADIO ASTRON OBSERV,CHARLOTTESVILLE,VA 22901.
C3 University of Cambridge; National Radio Astronomy Observatory (NRAO)
RP SASLAW, WC (corresponding author), UNIV VIRGINIA,DEPT ASTRON,POB 3818,UNIV STN,CHARLOTTESVILLE,VA 22903, USA.
NR 24
TC 8
Z9 9
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 43
EP 45
DI 10.1038/350043a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300056
DA 2026-03-10
ER

PT J
AU SCHLESINGER, ME
   JIANG, XJ
AF SCHLESINGER, ME
   JIANG, XJ
TI REVISED PROJECTION OF FUTURE GREENHOUSE WARMING
SO NATURE
LA English
DT Article
AB For the Intergovernmental Panel on Climate Change (IPCC) report 1, using a simple climate/ocean model, we made projections of the greenhouse warming to 2100.  Projections were made for four greenhouse-gas scenarios, whose radiative effects in 2100, expressed in terms of an equivalent amount of CO2, ranged from 2 to 5.5 times the pre-industrial CO2 concentration.  The projected global warming in 2100 for these scenarios, relative to 1990, ranged from 0.62-2.31-degrees-C for the minimum assumed CO2-doubling temperature sensitivity, DELTA-T2x = 1.5-degrees-C, to 1.61-5.15-degrees-C for the maximum sensitivity DELTA-T2x = 4.5-degrees-C.  Here we broaden these projections to include a recently suggested lower sensitivity, DELTA-T2x = 0.5-degrees-C.  We also revise all projections by prescribing, using the results of our analysis of simulations by a coupled atmosphere-ocean general circulation model, a lower value for a key parameter of the simple ocean model, II, which indicates the warming of the polar ocean relative to the warming of the non-polar ocean.  We find that, for any value of DELTA-T2x, the atmospheric temperature increases more rapidly with time as a consequence of the reduction in II.  We also find that a delay of ten years in initiating a 20-year transition from the IPCC 'business-as-usual' scenario to any other IPCC scenario has only a small effect on the projected warming in 2100, regardless of the value of DELTA-T2x.  This indicates that the penalty for a 10-year delay is small.
RP SCHLESINGER, ME (corresponding author), UNIV ILLINOIS,DEPT ATMOSPHER SCI,105 S GREGORY AVE,URBANA,IL 61801, USA.
NR 8
TC 53
Z9 56
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 219
EP 221
DI 
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900052
DA 2026-03-10
ER

PT J
AU ROTHENBURG, L
   BERLIN, AA
   BATHURST, RJ
AF ROTHENBURG, L
   BERLIN, AA
   BATHURST, RJ
TI MICROSTRUCTURE OF ISOTROPIC MATERIALS WITH NEGATIVE POISSON RATIO
SO NATURE
LA English
DT Article
AB MATERIALS that expand in the transverse direction under uniaxial extension, or that contract laterally when compressed, are said to have a negative Poisson's ratio, nu. For an isotropic elastic material, nu is the negative of the ratio of lateral to axial strain under uniaxial extension or compression. Despite the apparently counter-intuitive nature of this behaviour, nu < 0 has been observed for some anisotropic crystals 1 and materials comprised of fibrous networks 2,3, when loaded in a specific direction. Lakes 4 has described a class of foams that constitute perhaps the only known isotropic materials with negative-nu. Materials of this sort are expected to have interesting mechanical properties, such as high energy absorption and fracture resistance, which may be useful in some applications 4. Here we describe a general class of microstructures that lead to a negative Poisson's ratio, and show that some existing and hypothetical materials with this property share features common to this class. Our microstructural model provides insight into why natural materials of this kind are rare, and suggests a general methodology for designing such materials.
C1 ACAD SCI USSR,INST CHEM PHYS,MOSCOW 117977,USSR.
   ROYAL MIL COLL CANADA,DEPT CIVIL ENGN,KINGSTON K7K 5L0,ONTARIO,CANADA.
C3 Russian Academy of Sciences; N.N. Semenov Federal Research Centre for Chemical Physics, Russian Academy of Sciences; Royal Military College - Canada
RP ROTHENBURG, L (corresponding author), UNIV WATERLOO,DEPT CIVIL ENGN,WATERLOO N2L 3G1,ONTARIO,CANADA.
NR 9
TC 156
Z9 164
U1 4
U2 58
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 470
EP 472
DI 10.1038/354470a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800057
DA 2026-03-10
ER

PT J
AU RIVIERE, Y
   BLANK, V
   KOURILSKY, P
   ISRAEL, A
AF RIVIERE, Y
   BLANK, V
   KOURILSKY, P
   ISRAEL, A
TI PROCESSING OF THE PRECURSOR OF NF-KAPPA-B BY THE HIV-1 PROTEASE DURING ACUTE INFECTION
SO NATURE
LA English
DT Article
ID human immunodeficiency virus; transcription factor; binding; expression
AB TRANSCRIPTION of the human immunodeficiency virus type-1 (HIV-1) genome is regulated in part by cellular factors and is stimulated by activation of latently infected T cells.  T-cell activation also correlates with the induction of the factor NF-kappa-B which binds to two adjacent sites in the HIV-1 long terminal repeat 1.  This factor consists of two DNA-binding subunits of relative molecular mass 50,000 (50K) associated with two 65K subunits.  It is located in the nucleus in mature B cells, but is present in other cell types as an inactive cytoplasmic complex 2, 3.  External stimuli, including those that activate T cells, result in nuclear translocation of active NF-kappa-B.  The cloning of the complementary DNA for the 50K subunit 4,5 helped to identify an exclusively cytoplasmic 105K precursor (p105) (V.B., P.K. and A.I., manuscript submitted).  The expression of active NF-kappa-B might therefore also be regulated by the extent of processing of p105.  Because HIV-1 requires active NF-kappa-B for efficient transcription 1, we tested the effect of HIV-1 infection on the processing of the human 105K precursor.  We show here that the HIV-1 protease can process p105 and increases levels of active nuclear NF-kappa-B complex.
C1 INST PASTEUR,UNITE BIOL MOLEC GENE,25 RUE DR ROUX,F-75724 PARIS 15,FRANCE.
   INST PASTEUR,UNITE VIROL & IMMUNOL CELLULAIRE,CNRS,URA 1157,F-75724 PARIS 15,FRANCE.
C3 Pasteur Network; Universite Paris Cite; Institut Pasteur Paris; Pasteur Network; Universite Paris Cite; Institut Pasteur Paris; Centre National de la Recherche Scientifique (CNRS)
NR 13
TC 168
Z9 179
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 625
EP 626
DI 10.1038/350625a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200064
PM 2017258
DA 2026-03-10
ER

PT J
AU DILEO, AJ
   ALLEGREZZA, AE
AF DILEO, AJ
   ALLEGREZZA, AE
TI VALIDATABLE VIRUS REMOVAL FROM PROTEIN SOLUTIONS
SO NATURE
LA English
DT Article
RP DILEO, AJ (corresponding author), MILLIPORE CORP,80 ASHBY RD,BEDFORD,MA, USA.
NR 3
TC 10
Z9 11
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 420
EP 421
DI 10.1038/351420a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600065
PM 2034293
DA 2026-03-10
ER

PT J
AU MARTIN, J
   LANGER, T
   BOTEVA, R
   SCHRAMEL, A
   HORWICH, AL
   HARTL, FU
AF MARTIN, J
   LANGER, T
   BOTEVA, R
   SCHRAMEL, A
   HORWICH, AL
   HARTL, FU
TI CHAPERONIN-MEDIATED PROTEIN FOLDING AT THE SURFACE OF GROEL THROUGH A MOLTEN GLOBULE-LIKE INTERMEDIATE
SO NATURE
LA English
DT Article
ID ribulose bisphosphate carboxylase; liver dihydrofolate-reductase; heat-shock proteins; escherichia-coli; precursor proteins; ribulosebisphosphate-carboxylase; atp hydrolysis; rhodanese; hsp60; mitochondria
AB Folding of two monomeric enzymes mediated by groE has been reconstituted in vitro. The groEL protein stabilizes the polypeptides in a conformation resembling the 'molten globule' state. Mg-ATP and groES then promote the acquisition of ordered tertiary structure at the surface of groEL. Folding requires the hydrolysis of about 100 ATP molecules per protein monomer. This active process of surface-mediated chain folding might represent a general mechanism for the formation of protein structure in vivo.
C1 UNIV MUNICH,INST PHYSIOL CHEM,GOETHESTR 33,W-8000 MUNICH 2,GERMANY.
   YALE UNIV,SCH MED,HOWARD HUGHES MED INST,NEW HAVEN,CT 06510.
   YALE UNIV,SCH MED,DEPT HUMAN GENET,NEW HAVEN,CT 06510.
   UNIV MUNICH,INST ZOOL,W-8000 MUNICH 2,GERMANY.
C3 University of Munich; Yale University; Howard Hughes Medical Institute; Yale University; University of Munich
NR 54
TC 822
Z9 863
U1 1
U2 42
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 36
EP 42
DI 10.1038/352036a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800061
PM 1676490
DA 2026-03-10
ER

PT J
AU MURAKAMI, T
   INOUE, H
   NISHIMURA, J
   VANPARADIJS, J
   FENIMORE, EE
   ULMER, A
   YOSHIDA, A
AF MURAKAMI, T
   INOUE, H
   NISHIMURA, J
   VANPARADIJS, J
   FENIMORE, EE
   ULMER, A
   YOSHIDA, A
TI A GAMMA-RAY BURST PRECEDED BY X-RAY ACTIVITY
SO NATURE
LA English
DT Article
ID neutron stars; ginga; absorption; scattering; cyclotron; features
AB GAMMA-RAY bursts remain mysterious astrophysical phenomena.  The discovery of cyclotron harmonics 1-3 in their spectra is strong evidence that they originate from strongly magnetized neutron stars, but their energy source and photon production mechanism are unknown.  In observations of a gamma-ray burst using the Ginga astronomy satellite, we detected X-ray emission in the 2-10 keV energy range approximately 10 s before the onset of the gamma-ray event, as well as a tail of X-ray emission for approximately 30 s afterwards.  The long timescale and near black-body spectrum of the precursory X-ray emission suggests that the burst mechanism involves a transition from thermal to non-thermal photon production, and that the energy source for the burst comes from within the neutron star rather than from accretion.
C1 CTR HIGH ENERGY ASTROPHYS,1098 SJ AMSTERDAM,NETHERLANDS.
   INST CHEM & PHYS RES,SAITAMA 351,JAPAN.
   UNIV AMSTERDAM,ASTRON INST ANTON PANNEKOEK,AMSTERDAM,NETHERLANDS.
   UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545.
C3 University of Amsterdam; United States Department of Energy (DOE); Los Alamos National Laboratory
RP MURAKAMI, T (corresponding author), INST SPACE & ASTRONAUT SCI,1-1 YOSHINODAI 3-CHOME,SAGAMIHARA,KANAGAWA 229,JAPAN.
NR 24
TC 102
Z9 104
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 592
EP 594
DI 10.1038/350592a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200052
DA 2026-03-10
ER

PT J
AU DAVISON, W
   GRIME, GW
   MORGAN, JAW
   CLARKE, K
AF DAVISON, W
   GRIME, GW
   MORGAN, JAW
   CLARKE, K
TI DISTRIBUTION OF DISSOLVED IRON IN SEDIMENT PORE WATERS AT SUBMILLIMETER RESOLUTION
SO NATURE
LA English
DT Article
ID anoxic lake; manganese
AB MUCH effort has been directed at measuring concentration gradients at the sediment/water interface of aquatic systems, where the biogeochemical cycling of natural and pollutant species is particularly active 1.  Precise measurements of oxygen gradients using microelectrodes 2 and estimates from independently determined fluxes 3 suggest that concentration gradients in this region often extend only to depths of approximately 1 mm, much less than the resolution (approximately 1 centimetre) of conventional techniques 4-7.  We have developed a new method for measuring pore-water composition in which diffusive equilibrium is established rapidly (within minutes) in a thin film of gel inserted in the sediment. On removal, the dissolved components are fixed, allowing chemical measurements to be made at high spatial resolution (< 1 mm) on a stable solid phase. Using MeV-proton-induced X-ray emission (PIXE) to analyse the dried gel, we have measured iron concentrations in lacustrine pore waters at submillimetre resolution, revealing steep concentration gradients and sub-surface maxima consistent with a hypothesis of localized, reductive dissolution of fresh material.
C1 FRESHWATER BIOL ASSOC,AMBLESIDE LA22 0LP,CUMBRIA,ENGLAND.
   UNIV OXFORD,DEPT NUCL PHYS,OXFORD OX1 3RH,ENGLAND.
   INST FRESHWATER ECOL,AMBLESIDE LA22 0LP,CUMBRIA,ENGLAND.
C3 Freshwater Biological Association (FBA); University of Oxford; UK Centre for Ecology & Hydrology (UKCEH)
RP DAVISON, W (corresponding author), UNIV LANCASTER,INST ENVIRONM & BIOL SCI,LANCASTER LA1 4YQ,ENGLAND.
NR 19
TC 160
Z9 189
U1 0
U2 89
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 323
EP 325
DI 10.1038/352323a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900066
DA 2026-03-10
ER

PT J
AU POTTER, E
   BEHAN, DP
   FISCHER, WH
   LINTON, EA
   LOWRY, PJ
   VALE, WW
AF POTTER, E
   BEHAN, DP
   FISCHER, WH
   LINTON, EA
   LOWRY, PJ
   VALE, WW
TI CLONING AND CHARACTERIZATION OF THE CDNAS FOR HUMAN AND RAT CORTICOTROPIN RELEASING FACTOR-BINDING PROTEINS
SO NATURE
LA English
DT Article
ID amino-acid sequence; human-plasma; maternal plasma; human-placenta; pregnancy; hormone; acth; adrenalectomy; secretion; oxytocin
AB CORTICOTROPIN-releasing factor (CRF)1, is a potent stimulator of synthesis and secretion of preopiomelanocortin-derived peptides. Although CRF concentrations in the human peripheral circulation are normally low 2-4, they increase throughout pregnancy 4-8 and fall rapidly after parturition.  Maternal plasma CRF probably originates from the placenta, which responds to the bioactive peptide 5, 9, 10 and produces the peptide 9 and its messenger RNA 11.  Even though CRF concentrations in late gestational maternal plasma are similar to those in rat hypothalamic portal blood 12,13 and to those that can stimulate release of adrenocorticotropic hormone (ACTH) in vitro, maternal plasma ACTH concentrations increase only slightly with advancing gestation and remain within the normal range 14.  Several groups have now reported the existence of a CRF-binding protein in human plasma which inactivates CRF 15-20 and which has been proposed to prevent inappropriate pituitary-adrenal stimulation in pregnancy.  The binding protein was recently purified from human plasma 19.  We have now isolated and partially sequenced the binding protein, allowing us to clone and characterize its complementary DNA from human liver and rat brain. Expression of the cDNAs for human and rat binding protein in COS7 cells showed that these proteins bind CRF with the same affinity as the native human protein 15.  Both rat and human recombinant binding proteins inhibit CRF binding to a CRF antibody and inhibit CRF-induced ACTH release by pituitary cells in vitro.
C1 UNIV CALIF SAN DIEGO,DEPT PHARMACOL,LA JOLLA,CA 92037.
   UNIV READING,SCH ANIM & MICROBIAL SCI,DEPT BIOCHEM & PHYSIOL,READING RG6 2AJ,BERKS,ENGLAND.
C3 University of California System; University of California San Diego; University of Reading
RP POTTER, E (corresponding author), SALK INST BIOL STUDIES,CLAYTON FDN PEPTIDE BIOL,LA JOLLA,CA 92138, USA.
NR 33
TC 331
Z9 368
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 423
EP 426
DI 10.1038/349423a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400054
PM 1846945
DA 2026-03-10
ER

PT J
AU CHERNEVSKAYA, NI
   OBUKHOV, AG
   KRISHTAL, OA
AF CHERNEVSKAYA, NI
   OBUKHOV, AG
   KRISHTAL, OA
TI NMDA RECEPTOR AGONISTS SELECTIVELY BLOCK N-TYPE CALCIUM CHANNELS IN HIPPOCAMPAL-NEURONS
SO NATURE
LA English
DT Article
ID excitatory amino-acids; chick sensory neurons; guinea-pig invitro; synaptic transmission; omega-conotoxin; rat hippocampus; ca1 neurons; currents; modulation; activation
AB THE modulation of voltage-dependent calcium channels by various neurotransmitters had been demonstrated in many neurons 1-4,.  Because of the critical role of Ca2+ in transmitter release and, more generally, in transmembrane signalling, this modulation has important functional implications.  Hippocampal neurons posses low-threshold (T-type) Ca2+ channels and both L- and N-type high voltage-activated Ca2+ channels. 5-7  N-type Ca2+ channels are blocked selectively by omega-conotoxin 8, 9 and adenosine 10, 11.  These substances both block excitatory synaptic transmission in the hippocampus 12-13, whereas dihydropyridines, which selectively block L-type channels 14, are ineffective 12.  Excitatory synaptic transmission in the hippocampus displays a number of plasticity phenomena that are initiated by Ca2+ entry through ionic channels operated by N-methyl-D-aspartate (NMDA) receptors 15, 16.  Here we report that NMDA receptor agonists selectively and effectively depress N-type Ca2+ channels which are involved in neurotransmitter release from presynaptic sites.  The inhibitory effect is eliminated by the competitive NMDA antagonist D-2-amino-5-phosphonovalerate, does not require Ca2+ entry into the cell, and is probably receptor-mediated. This phenomenon may provide a negative feedback between the liberation of excitatory transmitter and entry of Ca2+ into the cell, and could be important in presynaptic inhibition and in the regulation of synaptic plasticity.
C1 AA BOGOMOLETZ PHYSIOL INST,BOGOMOLETZ STR 4,KIEV 252024,UKRAINE,USSR.
C3 National Academy of Sciences Ukraine; A.A. Bogomoletz Institute of Physiology
NR 26
TC 63
Z9 71
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 418
EP 420
DI 10.1038/349418a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400052
PM 1671527
DA 2026-03-10
ER

PT J
AU KOLCH, W
   HEIDECKER, G
   LLOYD, P
   RAPP, UR
AF KOLCH, W
   HEIDECKER, G
   LLOYD, P
   RAPP, UR
TI RAF-1 PROTEIN-KINASE IS REQUIRED FOR GROWTH OF INDUCED NIH/3T3 CELLS
SO NATURE
LA English
DT Article
ID signal transduction; v-raf; oncogene; phosphorylation
AB MANY growth factors regulate the cytoplasmic RAF-1 protein kinase 1-10, consistent with its having a central role in transduction of growth signals.  The kinase is ubiquitously expressed 11 and can promote proliferation 12, presumably in a manner dependent on growth-factor receptors and membrane-associated oncogenes 13-15.  We have now examined the dependence of serum- and TPa (12-O-tetradecanoylphorbol-13-acetate)-regulated NIH/3T3 cell growth on RAF-1 kinase to determine whether Raf-1 is essential for receptor signalling.  We inhibited Raf-1 function by expressing c-raf-1 antisense RNA or kinase-defective c-raf-1 mutants.  Antisense RNA for c-raf-1 interferes with proliferation of normal NIH/3T3 cells and reverts raf-transformed cells.  In revertant cells, DNA replication induced by serum or TPA was eliminated or reduced proportionately to the reduction in Raf protein levels.  Expression of a kinase-defective Raf-1 mutant (craf301) or a regulatory domain fragment (HCR) inhibited serum-induced NIH/3T3-cell proliferation and raf transformation even more efficiently. Inhibition by antisense RNA or craf301 blocked proliferation and transformation by Ki- and Ha-ras oncogenes.  We conclude that raf functions as an essential signal transducer downstream of serum growth factor receptors, protein kinase C and ras.
C1 NCI,FREDERICK CANC RES & DEV CTR,VIRAL CARCINOGENESIS LAB,FREDERICK,MD 21702.
   NCI,FREDERICK CANC RES & DEV CTR,PROGRAM RESOURCES INC DYNCORP,FREDERICK,MD 21702.
C3 National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Science Applications International Corporation (SAIC); SAIC-Frederick; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Science Applications International Corporation (SAIC); SAIC-Frederick
NR 26
TC 478
Z9 546
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 426
EP 428
DI 10.1038/349426a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400055
PM 1992343
DA 2026-03-10
ER

PT J
AU CAMPS, R
   BONTE, J
AF CAMPS, R
   BONTE, J
TI ENVIRONMENTAL-RESEARCH - THE EFFECTS OF AIR-POLLUTION ON PLANTS
SO NATURE
LA English
DT Article
C1 CTR DEPT ETUD & RECH ENVIRONM,F-64150 MOUREIUX,FRANCE.
RP CAMPS, R (corresponding author), ELF AQUITAINE,DIV ENVIRONM,F-92078 PARIS,FRANCE.
NR 0
TC 0
Z9 0
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 4
EP 5
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100004
DA 2026-03-10
ER

PT J
AU STEACY, SJ
   SAMMIS, CG
AF STEACY, SJ
   SAMMIS, CG
TI AN AUTOMATON FOR FRACTAL PATTERNS OF FRAGMENTATION
SO NATURE
LA English
DT Article
ID gouge
AB FRACTURES in the Earth's crust have a fractal structure over a wide range of length scales. A micromechanical model has been proposed 1 for the formation of fractal patterns of fragmentation in fault zones, based on the preferential fracture, at all length scales, of neighbours of a particle that have the same size as the particle itself. Here we explore this model in two and three dimensions using computer automata which implement these nearest-neighbour fracture rules. The automata produce random fractals which have capacity dimensions between 1.1 and 1.7 in two dimensions, and between 2.0 and 2.8 in three dimensions, the precise value depending on the packing geometry and the presence of long-range interactions imposed by uniform strain conditions. The fractal fragmentation patterns observed in natural systems tend to have dimensions between 2.5 and 2.7; we suggest that our model may permit an interpretation of these values in terms of the packing configuration (number of nearest neighbours) of the constituent particles.
RP STEACY, SJ (corresponding author), UNIV SO CALIF,DEPT GEOL SCI,LOS ANGELES,CA 90089, USA.
NR 9
TC 131
Z9 145
U1 1
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 250
EP 252
DI 10.1038/353250a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400056
DA 2026-03-10
ER

PT J
AU HILBERT, P
   LINDPAINTNER, K
   BECKMANN, JS
   SERIKAWA, T
   SOUBRIER, F
   DUBAY, C
   CARTWRIGHT, P
   DE GOUYON B
   JULIER, C
   TAKAHASI, S
   VINCENT, M
   GANTEN, D
   GEORGES, M
   LATHROP, GM
AF HILBERT, P
   LINDPAINTNER, K
   BECKMANN, JS
   SERIKAWA, T
   SOUBRIER, F
   DUBAY, C
   CARTWRIGHT, P
   DE GOUYON B
   JULIER, C
   TAKAHASI, S
   VINCENT, M
   GANTEN, D
   GEORGES, M
   LATHROP, GM
TI CHROMOSOMAL MAPPING OF 2 GENETIC-LOCI ASSOCIATED WITH BLOOD-PRESSURE REGULATION IN HEREDITARY HYPERTENSIVE RATS
SO NATURE
LA English
DT Article
ID renin gene; angiotensin-i; amplification; hybridization; cosegregation; linkage
AB The spontaneously hypertensive rat and the stroke-prone spontaneously hypertensive rat are useful models for human hypertension. In these strains hypertension is a polygenic trait, in which both autosomal and sex-linked genes can influence blood pressure 1-7. Linkage studies in crosses between the stroke-prone spontaneously hypertensive rat and the normotensive control strain Wistar-Kyoto have led to the localization of two genes, BP/SP-1 and BP/SP-2, that contribute significantly to blood pressure variation in the F2 population. BP/SP-1 and BP/SP-2 were assigned to rat chromosomes 10 and X, respectively. Comparison of the human and rat genetic maps indicates that BP/SP-1 could reside on human chromosome 17q in a region that also contains the angiotensin I-converting enzyme gene (ACE) 8. This encodes a key enzyme of the renin-angiotensin system 9, and is therefore a candidate gene in primary hypertension. A rat microsatellite marker of ACE was mapped to rat chromosome 10 within the region containing BP/SP-1.
C1 CTR ETUD POLYMORPHISME HUMAIN, 27 RUE JULIETTE DODU, F-75010 PARIS, FRANCE.
   CTR MOLEC MED, W-1115 BERLIN, GERMANY.
   INST RECH INTERDISCIPLINAIRE BIOL HUMAINE & NUCL, B-1070 BRUSSELS, BELGIUM.
   HARVARD UNIV, SCH MED,DEPT CELLULAR & MOLEC PHYSIOL, BOSTON, MA 02115 USA.
   UNIV HEIDELBERG, GERMAN INST HIGH BLOOD PRESSURE, W-6900 HEIDELBERG, GERMANY.
   COLL FRANCE, MED EXPTL LAB,INSERM,U36, F-75231 PARIS 05, FRANCE.
   UNIV CLAUDE BERNARD, PHYSIOL LAB, F-69373 Lyon, FRANCE.
   UNIV UTAH, DEPT HUMAN GENET, SALT LAKE CITY, UT 84132 USA.
   GENMARK INC, SALT LAKE CITY, UT 84108 USA.
   UNIV HEIDELBERG, DEPT PHARMACOL, W-6900 HEIDELBERG, GERMANY.
   KYOTO UNIV, FAC MED,INST LAB ANIM, KYOTO 606, JAPAN.
C3 Harvard University; Harvard Medical School; Ruprecht Karls University Heidelberg; Universite PSL; College de France; Institut National de la Sante et de la Recherche Medicale (Inserm); Universite Lyon 1; Utah System of Higher Education; University of Utah; Ruprecht Karls University Heidelberg; Kyoto University
NR 43
TC 596
Z9 627
U1 0
U2 13
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 521
EP 529
DI 10.1038/353521a0
PG 9
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300056
PM 1656270
DA 2026-03-10
ER

PT J
AU CORNALL, RJ
   PRINS, JB
   TODD, JA
   PRESSEY, A
   DELARATO, NH
   WICKER, LS
   PETERSON, LB
AF CORNALL, RJ
   PRINS, JB
   TODD, JA
   PRESSEY, A
   DELARATO, NH
   WICKER, LS
   PETERSON, LB
TI TYPE-1 DIABETES IN MICE IS LINKED TO THE INTERLEUKIN-1 RECEPTOR AND LSH/ITY/BCG GENES ON CHROMOSOME-1
SO NATURE
LA English
DT Article
ID nod mouse; nonobese; resistance; prevention; disease; cyclophosphamide; insulitis; mellitus; alpha; map
AB HUMAN type 1 (insulin-dependent) diabetes is a common autoimmune disease of the insulin-producing beta-cells of the pancreas which is caused by both genetic and environmental factors 1,2. Several features or the genetics and immunopathology of diabetes in nonobese diabetic (NOD) mice are shared with the human disease 1,3,4. Of the three diabetes-susceptibility genes, Idd-1 (refs 5-7), -3 and -4 (ref. 4) that have been mapped in mice to date, only in the case of Idd-1 is there any evidence for the identity of the gene product: allelic variation within the murine immune response I-A-beta gene and its human homologue HLA-DQB1 correlates with susceptibility, implying that I-A-beta is a component of Idd-1 (refs 5-11). We report here the mapping of Idd-5 to the proximal region of mouse chromosome 1. This region contains at least two candidate susceptibility genes, the interleukin-1 receptor gene (Il-1r1; ref. 12) and Lsh/Ity/Bcg (refs 13-19), which encodes resistance to bacterial and parasitic infections and affects the function of macrophages.
C1 MERCK SHARP & DOHME LTD, DEPT CELLULAR & MOLEC PHARMACOL, RAHWAY, NJ 07065 USA.
   MERCK SHARP & DOHME LTD, AUTOIMMUNE DIS RES, RAHWAY, NJ 07065 USA.
C3 Merck & Company; Merck & Company
RP CORNALL, RJ (corresponding author), JOHN RADCLIFFE HOSP, NUFFIELD DEPT SURG, OXFORD OX3 9DU, ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 30
TC 188
Z9 190
U1 0
U2 9
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 262
EP 265
DI 10.1038/353262a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400061
PM 1832743
DA 2026-03-10
ER

PT J
AU OHKUMA, Y
   SUMIMOTO, H
   HOFFMANN, A
   SHIMASAKI, S
   HORIKOSHI, M
   ROEDER, RG
AF OHKUMA, Y
   SUMIMOTO, H
   HOFFMANN, A
   SHIMASAKI, S
   HORIKOSHI, M
   ROEDER, RG
TI STRUCTURAL MOTIFS AND POTENTIAL SIGMA-HOMOLOGIES IN THE LARGE SUBUNIT OF HUMAN GENERAL TRANSCRIPTION FACTOR TFIIE
SO NATURE
LA English
DT Article
ID rna polymerase-ii; tata box; sequence; protein; cloning
AB THE general transcription factor TFIIE has an essential role in eukaryotic transcription initiation together with RNA polymerase II and other general factors 1,2 . Human TFIIE consists of two subunits of relative molecular mass 57,000 (TFIIE-alpha) and 34,000 (TFIIE-beta) 3-5 and joins the preinitiation complex after RNA polymerase II and TFIIF (ref. 5). Here we report the cloning and structure of a complementary DNA encoding 2 functional human TFIIE-alpha. TFIIE-alpha is necessary for transcription initiation together with TFIIE-beta, and recombinant TFIIE-alpha can fully replace the natural subunit in an in vitro transcription assay. The sequence contains several interesting structural motifs 6 (leucine repeat, zinc finger and helix-turn-helix) and sequence similarities to bacterial sigma-factors that suggest direct involvement in the regulation of transcription initiation.
C1 WHITTIER INST DIABET & ENDOCRINOL,LA JOLLA,CA 92037.
RP OHKUMA, Y (corresponding author), ROCKEFELLER UNIV,BIOCHEM & MOLEC BIOL LAB,NEW YORK,NY 10021, USA.
NR 30
TC 92
Z9 98
U1 1
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 398
EP 401
DI 10.1038/354398a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100053
PM 1956403
DA 2026-03-10
ER

PT J
AU SIKKEMA, AE
   ISRAEL, W
AF SIKKEMA, AE
   ISRAEL, W
TI BLACK-HOLE MERGERS AND MASS INFLATION IN A BOUNCING UNIVERSE
SO NATURE
LA English
DT Article
ID future
AB THE idea that our expanding Universe was born in a 'bounce'-the re-expansion of a previously contracting universe-is an old cosmogonical hypothesis, and continues to resurface 1-5 despite being overshadowed recently by hypotheses inspired by Guth's inflationary model. Here we show how recent developments in the physics of black-hole interiors force a major revision of our ideas of the final moments of a contracting universe, and remove a thermodynamic difficulty6,7 which had appeared to rule out any kind of bounce origin for our Universe. As the black hole formed by the collapse of a rotating star settles down, it absorbs part of the gravitational radiation emitted during the last moments of collapse. This radiation, strongly blue-shifted near the inner horizon, enormously increases the mass of the black hole's core. External observers cannot detect this mass, but it manifests itself dramatically when the black holes in a collapsing universe merge, a few minutes before the 'big crunch'. The mass of a rebounding universe is enormously inflated, and its specific entropy correspondingly reduced. This allows the expansion to begin from a state of relatively low disorder.
C1 UNIV ALBERTA, CANADIAN INST ADV RES, INST THEORET PHYS, COSMOL PROGRAM, EDMONTON T6G 2J1, ALBERTA, CANADA.
C3 Canadian Institute for Advanced Research (CIFAR); University of Alberta
NR 24
TC 11
Z9 11
U1 0
U2 3
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 45
EP 47
DI 10.1038/349045a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100043
DA 2026-03-10
ER

PT J
AU COMPTON, J
AF COMPTON, J
TI NUCLEIC-ACID SEQUENCE-BASED AMPLIFICATION
SO NATURE
LA English
DT Article
AB Nucleic acid sequence-based amplification (NASBA) is a primer-dependent technology that can be used for the continuous amplification of nucleic acids in a single mixture at one temperature.
RP COMPTON, J (corresponding author), CANGENE CORP,3403 AMER DR,MISSISSAUGA L4V 1T4,ONTARIO,CANADA.
NR 1
TC 1071
Z9 1552
U1 3
U2 338
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 91
EP 92
DI 10.1038/350091a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300075
PM 1706072
DA 2026-03-10
ER

PT J
AU BLOOMFIELD, SA
AF BLOOMFIELD, SA
TI 2 TYPES OF ORIENTATION-SENSITIVE RESPONSES OF AMACRINE CELLS IN THE MAMMALIAN RETINA
SO NATURE
LA English
DT Article
ID ganglion-cells; rabbit retina; structural basis; organization; selectivity; cortex
AB NEURONS sensitive to the orientation of light stimuli exist throughout the mammalian visual system 1-3, suggesting that this spatial feature is a fundamental cue used by the brain to decipher visual information. The most peripheral neurons known to show orientation sensitivity are the retinal ganglion cells.  Considerable morphological 4,5 and pharmacological 6-10 data suggest that the orientation sensitivity of ganglion cells is formed, at least partly, by the amacrine cells, which are laterally oriented interneurons presynaptic to the ganglion cells in the inner plexiform layer.  So far there have been few studies of the responses of amacrine cells to oriented visual stimuli and their role in forming orientation-sensitive responses in the retina remains unclear. Here I report the novel finding of a population of amacrine cells in the rabbit retina which are orientation-sensitive.  These amacrine cells can be divided into two subtypes, whose orientation sensitivity is manufactured by two distinct mechanisms.  The orientation sensitivity of the first subtype of amacrine cell is formed from the interactions of excitatory, centre-receptive field synaptic inputs and inhibitory inputs of opposite polarity, whereas that for cells of the second subtype seems to be the product of a marked asymmetry in their dendritic arbors.
RP BLOOMFIELD, SA (corresponding author), NYU MED CTR,DEPT OPHTHALMOL,550 1ST AVE,NEW YORK,NY 10016, USA.
FU National Eye Institute [R01EY007360] Funding Source: NIH RePORTER; NEI NIH HHS [R01 EY007360] Funding Source: Medline
NR 24
TC 31
Z9 35
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 347
EP 350
DI 10.1038/350347a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800095
PM 1706822
DA 2026-03-10
ER

PT J
AU PIOMELLI, D
   PILON, C
   GIROS, B
   SOKOLOFF, P
   MARTRES, MP
   SCHWARTZ, JC
AF PIOMELLI, D
   PILON, C
   GIROS, B
   SOKOLOFF, P
   MARTRES, MP
   SCHWARTZ, JC
TI DOPAMINE ACTIVATION OF THE ARACHIDONIC-ACID CASCADE AS A BASIS FOR D1/D2 RECEPTOR SYNERGISM
SO NATURE
LA English
DT Article
ID signal transduction; adenylate-cyclase; d1; metabolites; expression; neurons; inhibition
AB UNDERSTANDING the actions of the neurotransmitter dopamine in the brain is important in view of its roles in neuropsychiatric illnesses 1.  Dopamine D1 receptors, which stimulate both adenylyl cyclase 2 and phospholipase C3, and D2 receptors, which inhibit them 4,5, can nevertheless act synergistically to produce many electrophysiological and behavioural responses 6.  Because this functional synergism can occur at the level of single neurons, another, as yet unidentified, signalling pathway activated by dopamine has been hypothesized 7.  We report here that in Chinese hamster ovary (CHO) cells transfected with the D2 receptor complementary DNA, D2 agonists potently enhance arachidonic acid release, provided that such release has been initiated by stimulating constitutive purinergic receptors or by increasing intracellular Ca2+. In CHO cells expressing D1 receptors, D1 agonists exert no such effect. When D1 and D2 receptors are coexpressed, however, activation of both subtypes results in a marked synergistic potentiation of arachidonic acid release. The numerous actions of arachidonic acid and its metabolites in neuronal signal transduction 8 suggest that facilitation of its release may be implicated in dopaminergic responses, such as feedback inhibition mediated by D2 autoreceptors, and may constitute a molecular basis for D1/D2 receptor synergism.
RP PIOMELLI, D (corresponding author), CTR PAUL BROCA,INSERM,U109,UNITE NEUROBIOL & PHARMACOL,2TER RUE ALESIA,F-75014 PARIS,FRANCE.
NR 28
TC 265
Z9 280
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 164
EP 167
DI 10.1038/353164a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100053
PM 1909771
DA 2026-03-10
ER

PT J
AU BAILES, M
   LYNE, AG
   SHEMAR, SL
AF BAILES, M
   LYNE, AG
   SHEMAR, SL
TI A PLANET ORBITING THE NEUTRON-STAR PSR1829-10
SO NATURE
LA English
DT Article
ID binary pulsars; young
AB CONVENTIONAL optical techniques for detecting companions to stars have been unable to confirm the existence of other planetary systems. This is because of the small angular separation (less than an arcsecond) and relative luminosity (approximately 10(-10)) of any planet with respect to its parent star. As the velocity of the star due to the motion of a planet is likely to be only about one metre per second, detection through the Doppler shift of spectral lines in the stellar atmosphere is also impractical. Here we report observations which imply the existence of a planet-sized companion orbiting a neutron star, the pulsar PSR1829-10, whose motion can be seen by Doppler effects on the observed arrival times of the pulses from the rotating neutron star. The planet is about 10 times the mass of the Earth, and is in an almost circular six-month orbit. It is not clear whether it formed in the aftermath of the supernova that created the neutron star, or was pre-existing and somehow survived through the late phases of stellar evolution and neutron-star formation. In either case, the existence of the planet challenges conventional theories of the formation of neutron stars from supernovae and has important implications for the existence of planetary systems around other stars.
RP BAILES, M (corresponding author), UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,JODRELL BANK,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND.
NR 22
TC 90
Z9 95
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 311
EP 313
DI 10.1038/352311a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900061
DA 2026-03-10
ER

PT J
AU RATTO, GM
   ROBINSON, DW
   YAN, B
   MCNAUGHTON, PA
AF RATTO, GM
   ROBINSON, DW
   YAN, B
   MCNAUGHTON, PA
TI DEVELOPMENT OF THE LIGHT RESPONSE IN NEONATAL MAMMALIAN RODS
SO NATURE
LA English
DT Article
ID developing rat retina; outer segments; spectral sensitivity; postnatal-development; human infants; rhodopsin; desensitization; mechanisms; activation; vision
AB THE sensitivity to light is low in many neonatal mammals when compared with that in the adult.  In human infants at one month of age, for example, the dark-adapted sensitivity for detection of large stimuli is 50 times lower than in the adult 1-4, and in rats the overall sensitivity of the neonatal retina is also low compared with the adult 5, 6.  This low sensitivity in the neonate has been attributed to a number of factors 5-11, but the possibility that the photoreceptors themselves might be an important limitation on the overall visual sensitivity has not so far been clearly established.  Here we record the light response of single neonatal rat rods and find that the sensitivity is considerably lower than in the adult.  The response to a single photoisomerization is normal in the neonate, and the sensitivity deficit can therefore be attributed to a low level of functional rhodopsin. Opsin, the protein component of rhodopsin, must be present in normal amounts, as the sensitivity can be restored to adult levels by treating the retina with 9-cis retinal, an active homologue of the native chromophore 11-cis retinal.  The low sensitivity of photoreceptors in the neonate can therefore be attributed mainly to a low concentration of 11-cis retinal in the developing retina.
RP RATTO, GM (corresponding author), PHYSIOL LAB,DOWNING ST,CAMBRIDGE CB2 3EG,ENGLAND.
NR 24
TC 63
Z9 74
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 654
EP 657
DI 10.1038/351654a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200067
PM 2052091
DA 2026-03-10
ER

PT J
AU WILLSON, RC
   HUDSON, HS
AF WILLSON, RC
   HUDSON, HS
TI THE SUNS LUMINOSITY OVER A COMPLETE SOLAR-CYCLE
SO NATURE
LA English
DT Article
ID irradiance
AB THE Active Cavity Radiometer Irradiance Monitor (ACRIM I), an instrument carried on NASA's Solar Maximum Mission satellite, measured the Sun's luminosity (total power outflow) from early 1980 to late 1989 1-5.  Here we present the first account of the complete ACRIM I data set, and give evidence confirming our previous suggestion that solar luminosity varies with the 11-year solar cycle 6.  As previously reported, this slow variation closely follows statistical measures of the distribution of magnetic and photospheric features on the Sun's surface 4-8.  But there was an exception to this correlation in the form of a remarkable irradiance excess during 1980, at about the time of the sunspot maximum of solar cycle 21.  The linkage, over a whole cycle, of luminosity variation to photospheric activity suggests the existence of an unknown physical mechanism other than the thermal diffusion model that explains luminosity deficits due to sunspots.  Luminosity models connecting total irradiance to global indicators of solar activity, such as the equivalent width of the 1,083-nm helium line, are consistent with the gross features of the variability, but fail to account for the 1980 irradiance excess.
C1 UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093.
C3 University of California System; University of California San Diego
RP WILLSON, RC (corresponding author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA.
NR 13
TC 273
Z9 290
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 42
EP 44
DI 10.1038/351042a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300051
DA 2026-03-10
ER

PT J
AU STUART, JJ
   BROWN, SJ
   BEEMAN, RW
   DENELL, RE
AF STUART, JJ
   BROWN, SJ
   BEEMAN, RW
   DENELL, RE
TI A DEFICIENCY OF THE HOMEOTIC COMPLEX OF THE BEETLE TRIBOLIUM
SO NATURE
LA English
DT Article
ID gene fushi-tarazu; drosophila-melanogaster; bithorax complex; molecular analysis; antennapedia gene; segmentation; embryo; activation; head
AB IN Drosophila, the establishment of regional commitments along most of the anterior/posterior axis of the developing embryo depends on two clusters of homeotic genes:  the Antennapedia complex (ANT-C) and the bithorax complex (BX-C).  The red flour beetle has a single complex (HOM-C) representing the homologues of the ANT-C and BX-C in juxtaposition 1.  Beetles trans-heterozygous for two particular HOM-C mutations spontaneously generate a large deficiency, presumably by an exchange within the common region of two overlapping inversions.  Genetic and molecular results indicate that this deficiency spans at least the interval between the Deformed and abdominal-A homologues.  In deficiency homozygous embryos, all gnathal, thoracic and abdominal segments develop antennal appendages, suggesting that a gene(s) has been deleted that acts to distinguish trunk from head.  There is no evidence that beetles have a homologue of the segmentation gene fushi tarazu of similar genomic location and function.  On the basis of the genetic tractability 2, convenient genome size and organization of Tribolium 3, and its relatively long phylogenetic divergence from Drosophila (> 300 million years), we have integrated developmental genetic and molecular analyses of the HOM-C.  We isolated about 70 mutations in the complex representing at least six complementation groups.  The homeotic phenotypes of adults 2 and lethal embryos lead us to believe that these beetle genes are homologous with the Drosophila genes indicated in Fig. 1.
C1 KANSAS STATE UNIV AGR & APPL SCI,DIV BIOL,ACKERT HALL,MANHATTAN,KS 66506.
   USDA ARS,N CENT REG,US GRAIN MKT RES LAB,MANHATTAN,KS 66502.
C3 Kansas State University; United States Department of Agriculture (USDA)
NR 24
TC 151
Z9 162
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 72
EP 74
DI 10.1038/350072a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300068
PM 11536480
DA 2026-03-10
ER

PT J
AU THERIOT, JA
   MITCHISON, TJ
AF THERIOT, JA
   MITCHISON, TJ
TI ACTIN MICROFILAMENT DYNAMICS IN LOCOMOTING CELLS
SO NATURE
LA English
DT Article
ID heavy-chain gene; electric-fields; microtubules; fluorescence; fibroblasts; motility; myosin; organization; lamellipodia; cytoskeleton
AB The dynamic behaviour of actin filaments has been directly observed in living, motile cells using fluorescence photoactivation. In goldfish epithelial keratocytes, the actin microfilaments in the lamellipodium remain approximately fixed relative to the substrate as the cell moves over them, regardless of cell speed. The rate of turnover of actin subunits in the lamellipodium is remarkably rapid. Cell movement is directly and tightly coupled to the formation of new actin filaments at the leading edge.
C1 UNIV CALIF SAN FRANCISCO, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA.
C3 University of California System; University of California San Francisco
RP THERIOT, JA (corresponding author), UNIV CALIF SAN FRANCISCO, DEPT PHYSIOL & BIOPHYS, SAN FRANCISCO, CA 94143 USA.
NR 41
TC 699
Z9 814
U1 0
U2 65
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 126
EP 131
DI 10.1038/352126a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700045
PM 2067574
DA 2026-03-10
ER

PT J
AU GRAY, AD
   CRAM, LE
   EKERS, RD
   GOSS, WM
AF GRAY, AD
   CRAM, LE
   EKERS, RD
   GOSS, WM
TI A FILAMENTARY RADIO-SOURCE NEAR THE GALACTIC-CENTER
SO NATURE
LA English
DT Article
ID emission; model
AB NEAR the Galactic Centre are several filamentary radio structures that have become known as 'threads' 1 and which are thought to signify either magnetic loops 2 or electric current paths 3 between active regions and the galactic magnetic field. Using the Molonglo Observatory Synthesis Telescope, we have found a new elongated radio source, G359.1-0.2, within 1-degrees of the Galactic Centre. Observations with the Australia Telescope Compact Array and the Very Large Array show it to be filamentary in nature, extending more than 20 arcmin in length but only 10 aresec wide. This object is spectrally similar to the previously known threads, but unlike them has kinks along its length, and does not appear to be obviously connected with any active region that might be responsible for its generation.
C1 AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA.
   NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801.
C3 Commonwealth Scientific & Industrial Research Organisation (CSIRO); Australia Telescope National Facility; National Radio Astronomy Observatory (NRAO)
RP GRAY, AD (corresponding author), UNIV SYDNEY,SCH PHYS,SYDNEY,NSW 2006,AUSTRALIA.
NR 19
TC 51
Z9 51
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 237
EP 239
DI 10.1038/353237a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400051
DA 2026-03-10
ER

PT J
AU BROCKDORFF, N
   ASHWORTH, A
   KAY, GF
   COOPER, P
   SMITH, S
   MCCABE, VM
   NORRIS, DP
   PENNY, GD
   PATEL, D
   RASTAN, S
AF BROCKDORFF, N
   ASHWORTH, A
   KAY, GF
   COOPER, P
   SMITH, S
   MCCABE, VM
   NORRIS, DP
   PENNY, GD
   PATEL, D
   RASTAN, S
TI CONSERVATION OF POSITION AND EXCLUSIVE EXPRESSION OF MOUSE XIST FROM THE INACTIVE X-CHROMOSOME
SO NATURE
LA English
DT Article
ID controlling elements; construction
AB X-CHROMOSOME inactivation in mammals is a regulatory phenomenon whereby one of the two X chromosomes in female cells is genetically inactivated, resulting in dosage compensation for X-linked genes between males and females 1.  In both man and mouse, X-chromosome inactivation is thought to proceed from a single cis-acting switch region or inactivation centre (XIC/Xic) 2-5.  In the human, XIC has been mapped to band Xq13 (ref. 6) and in the mouse to band XD (ref. 7), and comparative mapping has shown that the XIC regions in the two species are syntenic 8.  The recently described human XIST gene maps to the XIC region 6 and seems to be expressed only from the inactive X chromosome 9.  We report here that the mouse Xist gene maps to the Xic region of the mouse X chromosome and, using an interspecific Mus spretus/Mus musculus domesticus F1 hybrid mouse carrying the T(X; 16)16H translocation, show that Xist is exclusively expressed from the inactive X chromosome.  Conservation between man and mouse of chromosomal position and unique expression exclusively from the inactive X chromosome lends support to the hypothesis that XIST and its mouse homologue are involved in X-chromosome inactivation.
C1 MRC,CLIN RES CTR,COMPARAT BIOL SECT,HARROW HA1 3UJ,MIDDX,ENGLAND.
   INST CANC RES,CHESTER BEATTY LABS,LONDON SW3 6JB,ENGLAND.
C3 Medical Research Council Clinical Trials Unit; University of London; Institute of Cancer Research - UK; Royal Marsden NHS Foundation Trust
NR 22
TC 568
Z9 646
U1 0
U2 30
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 329
EP 331
DI 10.1038/351329a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600065
PM 2034279
DA 2026-03-10
ER

PT J
AU NIGGLI, E
   LEDERER, WJ
AF NIGGLI, E
   LEDERER, WJ
TI MOLECULAR OPERATIONS OF THE SODIUM CALCIUM EXCHANGER REVEALED BY CONFORMATION CURRENTS
SO NATURE
LA English
DT Article
ID guinea-pig; voltage dependence; ventricular cells; mechanism; vesicles; pumps
AB THE sodium-calcium exchanger is critical in the normal functioning of many cells 1,2.  In heart muscle, it is the principal way by which the cells keep the concentration of intracellular calcium low, pumping out the Ca2+ that enters the cytosol through L-type Ca2+ channels 3,4.  The exchanger may also contribute to the triggering of Ca2+ release during voltage-activated excitation-contraction coupling in heart 5,6.  Time resolved examination of the conformational changes of macromolecules in living cells has so far been largely restricted to ion-channel proteins whose gating is voltage-dependent 7,8.  We have now directly measured electrical currents arising from the molecular rearrangements of the sarcolemmal Na-Ca exchanger.  Changes in the conformation of the exchanger protein were activated by a rapid increase in the intracellular calcium concentration produced by flash photolysis of caged calcium 9 in voltage-clamped heart cells.  Two components of membrane current were produced, reflecting a calcium-dependent conformational change of the transporter proteins and net transport of ions by the exchanger.  The properties of these components provide evidence that the Na-Ca exchanger protein undergoes two consecutive membrane-crossing molecular transitions that each move charge, and that there are at least 250 exchangers per mu-m2 turning over up to 2,500 times per second.
C1 UNIV MARYLAND,SCH MED,DEPT PHYSIOL,BALTIMORE,MD 21201.
   MED BIOTECHNOL CTR,BALTIMORE,MD 21201.
C3 University System of Maryland; University of Maryland Baltimore
NR 27
TC 135
Z9 145
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 621
EP 624
DI 10.1038/349621a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000063
PM 2000135
DA 2026-03-10
ER

PT J
AU PYKE, GH
AF PYKE, GH
TI WHAT DOES IT COST A PLANT TO PRODUCE FLORAL NECTAR
SO NATURE
LA English
DT Article
ID bells blandfordia-nobilis; pollination ecology; standing crop; seed-set; manipulations; hummingbird; patterns; flowers; removal
AB TO understand the adaptive nature of floral nectar production it is necessary to determine for individual plants the associated costs and benefits in terms of growth and/or reproduction 1-3.  Nectar production may use up to 37% of a plant's available energy 4,5 but might not affect growth or reproduction.  I report here that removal of nectar from flowers of Christmas bells (Blandfordia nobilis) increased the plant's net nectar production but reduced its ability to produce seeds.  To our knowledge this is the first demonstration that nectar production entails a cost to a plant in terms of growth and/or reproduction and that both the gains and costs associated with nectar production may be estimated in the same 'currency' (seeds).  As a plant's nectar production increases, there should therefore be a trade-off between pollinator-mediated increases in numbers of fertilized seeds 1-3 and decreases in seed number due to the costs of producing the nectar.
RP PYKE, GH (corresponding author), AUSTRALIAN MUSEUM,DIV ENVIRONM SCI,6-8 COLL ST,SYDNEY,NSW 2000,AUSTRALIA.
NR 14
TC 347
Z9 394
U1 0
U2 97
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 58
EP 59
DI 10.1038/350058a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300063
DA 2026-03-10
ER

PT J
AU DATTA, B
   WEINER, AM
AF DATTA, B
   WEINER, AM
TI GENETIC-EVIDENCE FOR BASE-PAIRING BETWEEN U2 AND U6 SNRNA IN MAMMALIAN MESSENGER-RNA SPLICING
SO NATURE
LA English
DT Article
ID small nuclear ribonucleoprotein; 2'-ome rna; yeast; u1; oligonucleotides; particles; selection; invitro; u4
AB REMOVAL of introns from eukaryotic nuclear messenger RNA precursors is catalysed by a large ribonucleoprotein complex called the spliceosome, which consists of four small nuclear ribonucleoprotein particles (U1, U2, U5, and U4/U6 snRNPs) and auxiliary protein factors 1,2.  We have begun a genetic analysis of mammalian U2 snRNA by making second-site mutations in a suppressor U2 snRNA 3.  Here we find that several mutations in the 5' end of U2 (nucleotides 3-8) are deleterious and that one of these can be rescued by compensatory base changes in the 3' end of U6 (nucleotides 92-95).  The results demonstrate genetically that the base-pairing interaction between U2 (nucleotides 3-11) and U6 snRNA (nucleotides 87-95), originally proposed on the basis of psoralen photocrosslinking experiments 4, can influence the efficiency of mRNA splicing in mammals.  The U2/U6 interaction in yeast, however, is fairly tolerant to mutation 5 (D. J. Field and J. D. Friesen, personal communication), emphasizing the potential for facultative RNA interactions within the spliceosome.
RP DATTA, B (corresponding author), YALE UNIV,SCH MED,DEPT MOLEC BIOPHYS & BIOCHEM,NEW HAVEN,CT 06510, USA.
NR 29
TC 159
Z9 168
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 821
EP 824
DI 10.1038/352821a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400066
PM 1831879
DA 2026-03-10
ER

PT J
AU LUESCHER, IF
   ROMERO, P
   CEROTTINI, JC
   MARYANSKI, JL
AF LUESCHER, IF
   ROMERO, P
   CEROTTINI, JC
   MARYANSKI, JL
TI SPECIFIC BINDING OF ANTIGENIC PEPTIDES TO CELL-ASSOCIATED MHC CLASS-I MOLECULES
SO NATURE
LA English
DT Article
ID major histocompatibility complex; cytolytic t-cells; immunogenic peptides; recognition; hla; capacity; gene
AB T LYMPHOCYTES recognize antigen in the form of peptides that associate with specific alleles of class I or class II major histocompatibility (MHC) molecules 1,2.  By contrast with the clear MHC allele-specific binding of peptides to purified class II molecules 3-6 purified solubilized class I molecules either bind relatively poorly 7 or show degenerate specificity 8-11.  Using photoaffinity labelling, we demonstrate here the specific interaction of peptides with cell-associated MHC class I molecules and show that this involves metabolically active processes.
RP LUESCHER, IF (corresponding author), LUDWIG INST CANC RES,LAUSANNE BRANCH,CH-1066 EPALINGES,SWITZERLAND.
NR 32
TC 62
Z9 78
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 72
EP 74
DI 10.1038/351072a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300063
PM 2027386
DA 2026-03-10
ER

PT J
AU FERGUSONSMITH, AC
   CATTANACH, BM
   BARTON, SC
   BEECHEY, CV
   SURANI, MA
AF FERGUSONSMITH, AC
   CATTANACH, BM
   BARTON, SC
   BEECHEY, CV
   SURANI, MA
TI EMBRYOLOGICAL AND MOLECULAR INVESTIGATIONS OF PARENTAL IMPRINTING ON MOUSE CHROMOSOME-7
SO NATURE
LA English
DT Article
ID growth factor-ii; gene-expression; embryogenesis; chimeras; pattern; cells; mice; rna
AB MOUSE embryos with duplications of whole maternal (parthenogenetic and gynogenetic) or paternal (androgenetic) genomes show reciprocal phenotypes and do not develop to term 1, 2.  Genetic complementation has identified the distal region of chromosome 7 (Chr 7) as one of the regions for which both a maternal and paternal chromosome copy are essential for normal development, presumably because of the presence of imprinted genes whose expression is dependent on their parental origin 3, 4.  Embryos with the maternal duplication and paternal deficiency of distal Chr 7 are growth retarded and died around day 16 of gestation; the reciprocal paternal duplication embryos die at an unidentified earlier stage 4.  We report here the incorporation of cells with the paternal duplication into chimaeras, resulting in a striking growth enhancement of the embryos.  One gene located on mouse distal Chr 7 (ref. 5) is the insulin-like growth factor 2 (Igf2) gene, an embryonic mitogen 6.  In embryos with the maternal duplication of distal Chr 7, the two maternal alleles of the Igf2 gene are repressed.  The presence of two paternal alleles of this gene in many cells is probably responsible for the growth enhancement observed in chimaeras.  We propose that there are other imprinted genes in this Chr 7 region.  We also compare the imprinting of this subgenomic region with phenotypes resulting from the duplication of the whole parental genome in parthenogenones and androgenones.
C1 MRC,RADIOBIOL UNIT,OXFORD OX1 0RD,ENGLAND.
RP FERGUSONSMITH, AC (corresponding author), AFRC,INST ANIM PHYSIOL & GENET RES,DEPT MOLEC EMBRYOL,CAMBRIDGE CB2 4AT,ENGLAND.
NR 30
TC 263
Z9 307
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 667
EP 670
DI 10.1038/351667a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200072
PM 2052093
DA 2026-03-10
ER

PT J
AU BISCHOFF, FR
   PONSTINGL, H
AF BISCHOFF, FR
   PONSTINGL, H
TI CATALYSIS OF GUANINE-NUCLEOTIDE EXCHANGE ON RAN BY THE MITOTIC REGULATOR RCC1
SO NATURE
LA English
DT Article
ID chromosome condensation; human-gene; protein; onset; cloning; mutant; cdna; dna; gdp
AB THE product of the gene RCC1 (regulator of chromosome condensation) in a BHK cell line is involved in the control of mitotic events 1. Homologous genes have been found in Xenopus 2, Drosophila 3 and yeast 4,5. A human genomic DNA fragment and complementary DNA that complement a temperature-sensitive mutation of RCC1 in BHK21 cells 6,7 encode a protein of relative molecular mass 45,000 (M(r) 45K) which is located in the nucleus and binds to chromatin 8. We have recently isolated a protein from HeLa cells that strongly binds an anti-RCC1 antibody and has the same molecular mass, DNA-binding properties, and amino-acid sequence as the 205 residues already identified 9. HeLa cell RCC1 is complexed to a protein of M(r) 25K (ref. 9). We have shown 10 that this 25K protein has a sequence homologous to the translated reading frame of TC4, a cDNA found by screening a human teratocarcinoma cDNA library with oligonucleotides coding for a ras consensus sequence 11, and that the protein binds GDP and GTP. We have referred to this protein as the Ran protein (ras-related nuclear protein). In addition to the fraction of Ran protein complexed to RCC1, a 25-fold molar excess of the protein over RCC1 was found in the nucleoplasm of HeLa cells. Here we show that RCC1 specifically catalyses the exchange of guanine nucleotides on the Ran protein but not on the protein c-Ha-ras p2l (p21ras).
C1 DEUTSCH KREBSFORSCHUNGSZENTRUM,MOLEC BIOL MITOSIS PROJECT,NEUENHEIMER FELD 280,W-6900 HEIDELBERG,GERMANY.
C3 Helmholtz Association; German Cancer Research Center (DKFZ)
NR 20
TC 586
Z9 686
U1 0
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 80
EP 82
DI 10.1038/354080a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900063
PM 1944575
DA 2026-03-10
ER

PT J
AU LI, JD
   CARROLL, J
   ELLAR, DJ
AF LI, JD
   CARROLL, J
   ELLAR, DJ
TI CRYSTAL-STRUCTURE OF INSECTICIDAL DELTA-ENDOTOXIN FROM BACILLUS-THURINGIENSIS AT 2.5-A RESOLUTION
SO NATURE
LA English
DT Article
ID brush-border membrane; var tenebrionis; macromolecular crystallography; protein-structure; specificity; gene; binding; purification; coleoptera; mechanism
AB The structure of the delta-endotoxin from Bacillus thuringiensis subsp. tenebrionis that is specifically toxic to Coleoptera insects (beetle toxin) has been determined at 2.5 angstrom resolution. It comprises three domains which are, from the N- to C-termini, a seven-helix bundle, a three-sheet domain, and a beta-sandwich. The core of the molecule encompassing all the domain interfaces is built from conserved sequence segments of the active delta-endotoxins. Therefore the structure represents the general fold of this family of insecticidal proteins. The bundle of long, hydrophobic and amphipathic helices is equipped for pore formation in the insect membrane, and regions of the three-sheet domain are probably responsible for receptor binding.
C1 UNIV CAMBRIDGE, DEPT BIOCHEM, CAMBRIDGE CB2 1QW, ENGLAND.
C3 University of Cambridge
RP LI, JD (corresponding author), MRC, MOLEC BIOL LAB, HILLS RD, CAMBRIDGE CB2 2QH, ENGLAND.
NR 47
TC 647
Z9 766
U1 3
U2 75
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 815
EP 821
DI 10.1038/353815a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200050
PM 1658659
DA 2026-03-10
ER

PT J
AU KURIYAN, J
   KRISHNA, TSR
   WONG, L
   GUENTHER, B
   PAHLER, A
   WILLIAMS, CH
   MODEL, P
AF KURIYAN, J
   KRISHNA, TSR
   WONG, L
   GUENTHER, B
   PAHLER, A
   WILLIAMS, CH
   MODEL, P
TI CONVERGENT EVOLUTION OF SIMILAR FUNCTION IN 2 STRUCTURALLY DIVERGENT ENZYMES
SO NATURE
LA English
DT Article
ID glutathione-reductase; thioredoxin reductase; escherichia-coli; active-site; resolution; protein; binding; crystallography; refinement; disulfide
AB AN example of two related enzymes that catalyse similar reactions but possess different active sites is provided by comparing the structure of Escherichia coli thioredoxin reductase with glutathione reductase 1.  Both are dimeric enzymes that catalyse the reduction of disulphides by pyridine nucleotides through an enzyme disulphide and a flavin 2.  Human glutathione reductase contains four structural domains within each molecule:  the flavin-adenine dinucleotide (FAD)- and nicotinamide-adenine dinucleotide phosphate (NADPH)-binding domains, the 'central' domain and the C-terminal domain that provides the dimer interface and part of the active site 3,4.  Although both enzymes share the same catalytic mechanism and similar tertiary structures, their active sites do not resemble each other 5,6.  We have determined the crystal structure of E. coli thioredoxin reductase at 2 angstrom resolution, and show that thioredoxin reductase lacks the domain that provides the dimer interface in glutathione reductase, and forms a completely different dimeric structure.  The catalytically active disulphides are located in different domains on opposite sides of the flavin ring system.  This suggests that these enzymes diverged from an ancestral nucleotide-binding protein and acquired their disulphide reductase activities independently.
C1 ROCKEFELLER UNIV,HOWARD HUGHES MED INST,NEW YORK,NY 10021.
   COLUMBIA UNIV,DEPT MOLEC BIOPHYS & BIOCHEM,NEW YORK,NY 10032.
   DEPT VET AFFAIRS MED CTR,ANN ARBOR,MI 48105.
   UNIV MICHIGAN,DEPT BIOL CHEM,ANN ARBOR,MI 48109.
C3 Rockefeller University; Howard Hughes Medical Institute; Columbia University; University of Michigan System; University of Michigan
RP KURIYAN, J (corresponding author), ROCKEFELLER UNIV,1230 YORK AVE,NEW YORK,NY 10021, USA.
NR 26
TC 174
Z9 194
U1 1
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 172
EP 174
DI 10.1038/352172a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700062
PM 2067578
DA 2026-03-10
ER

PT J
AU MARINO, BD
   MCELROY, MB
AF MARINO, BD
   MCELROY, MB
TI ISOTOPIC COMPOSITION OF ATMOSPHERIC CO2 INFERRED FROM CARBON IN C4 PLANT CELLULOSE
SO NATURE
LA English
DT Article
ID past 2 century; leaf conductance; tree rings; partial-pressure; antarctic ice; record; discrimination; fractionation; assimilation; dioxide
AB The isotopic composition of atmospheric carbon dioxide provides an important constraint for models of the global carbon cycle. It is shown that carbon in C4 plants preserves an isotopic record of the CO2 used in photosynthesis. Data for the maize plant Zea mays yield results for the isotopic composition of atmospheric CO2 consistent with measurements of modern air and air trapped in polar ice. Data from C4 plants may thus be used to extend the isotopic record of atmospheric CO2 into the past, complementing data from other sources.
C1 HARVARD UNIV, DIV APPL SCI, CAMBRIDGE, MA 02138 USA.
C3 Harvard University
RP MARINO, BD (corresponding author), HARVARD UNIV, DEPT EARTH & PLANETARY SCI, CAMBRIDGE, MA 02138 USA.
NR 47
TC 377
Z9 430
U1 0
U2 43
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 127
EP 131
DI 10.1038/349127a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800048
DA 2026-03-10
ER

PT J
AU BROEK, D
   BARTLETT, R
   CRAWFORD, K
   NURSE, P
AF BROEK, D
   BARTLETT, R
   CRAWFORD, K
   NURSE, P
TI INVOLVEMENT OF P34CDC2 IN ESTABLISHING THE DEPENDENCY OF S-PHASE ON MITOSIS
SO NATURE
LA English
DT Article
ID yeast schizosaccharomyces-pombe; cell-division cycle; fission yeast; protein-kinase; dna-replication; tyrosine phosphorylation; chromosome condensation; colorimetric method; molecular-cloning; mitotic control
AB Mutants of cdc2+ can disrupt the dependency of S phase on completion of the previous mitosis.  By changing the state of p34cdc2 it is possible to reprogramme a cell from entering mitosis to undergoing S phase.  This leads to the proposal that the cell cycle can be considered a p34cdc2 cycle, and has implications for the evolution of life cycles.
C1 UNIV OXFORD,IMPERIAL CANC RES FUND,DEPT BIOCHEM,MICROBIOL UNIT,OXFORD OX1 3QU,ENGLAND.
C3 University of Oxford
NR 59
TC 327
Z9 345
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 388
EP 393
DI 10.1038/349388a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400040
PM 1992340
DA 2026-03-10
ER

PT J
AU SCHWER, B
   GUTHRIE, C
AF SCHWER, B
   GUTHRIE, C
TI PRP16 IS AN RNA-DEPENDENT ATPASE THAT INTERACTS TRANSIENTLY WITH THE SPLICEOSOME
SO NATURE
LA English
DT Article
ID nuclear ribonucleoprotein particle; messenger-rna; saccharomyces-cerevisiae; monoclonal-antibody; polyacrylamide gels; splicing invitro; escherichia-coli; t-antigen; yeast; protein
AB The assembly of the spliceosome is an ATP-dependent process.  The splicing factor PRP16 contains variations of several motifs that define the eIF-4A-like ATP-dependent RNA helicase family.  The protein has now been purified and shown to exhibit RNA-dependent ATPase activity.  PRP16 is required specifically for the second catalytic step of the splicing reaction in vitro.  This function requires ATP binding and/or hydrolysis, which appears to be concomitant with release of the protein from the spliceosome.  PRP16 may be the prototype for a set of splicing factors which use ATP to drive a cycle of conformational changes.
RP SCHWER, B (corresponding author), UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143, USA.
NR 51
TC 301
Z9 332
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 494
EP 499
DI 10.1038/349494a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100056
PM 1825134
DA 2026-03-10
ER

PT J
AU RUDENSKY, AY
   PRESTONHURLBURT, P
   HONG, SC
   BARLOW, A
   JANEWAY, CA
AF RUDENSKY, AY
   PRESTONHURLBURT, P
   HONG, SC
   BARLOW, A
   JANEWAY, CA
TI SEQUENCE-ANALYSIS OF PEPTIDES BOUND TO MHC CLASS-II MOLECULES
SO NATURE
LA English
DT Article
ID antigen-binding site; t-cell recognition; histocompatibility molecules; monoclonal-antibody; ia; specificity; complex; clones; chain; restriction
AB CD4 T cells recognize peptide fragments of foreign proteins bound to self class II molecules of the major histocompatibility complex (MHC). Naturally processed peptide fragments bound to MHC class II molecules are peptides of 13-17 amino acids which appear to be precessively truncated from the carboxy terminus, perhaps after binding to the MHC class II molecule. The finding of predominant self peptides has interesting implications for antigen processing and self-non-self discrimination.
C1 YALE UNIV,SCH MED,PSYCHOL SECT,NEW HAVEN,CT 06510.
   YALE UNIV,SCH MED,HOWARD HUGHES MED INST,NEW HAVEN,CT 06510.
C3 Yale University; Yale University; Howard Hughes Medical Institute
NR 49
TC 1038
Z9 1146
U1 0
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 622
EP 627
DI 10.1038/353622a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200057
PM 1656276
DA 2026-03-10
ER

PT J
AU [Anonymous]
AF [Anonymous]
TI NATURES MANIFESTO FOR BRITISH SCIENCE
SO NATURE
LA English
DT Article
NR 0
TC 0
Z9 0
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 105
EP 112
DI 
PG 8
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100022
PM 1891041
DA 2026-03-10
ER

PT J
AU TODD, JA
   AITMAN, TJ
   CORNALL, RJ
   GHOSH, S
   HALL, JRS
   HEARNE, CM
   KNIGHT, AM
   LOVE, JM
   MCALEER, MA
   PRINS, JB
   RODRIGUES, N
   LATHROP, M
   PRESSEY, A
   DELARATO, NH
   PETERSON, LB
   WICKER, LS
AF TODD, JA
   AITMAN, TJ
   CORNALL, RJ
   GHOSH, S
   HALL, JRS
   HEARNE, CM
   KNIGHT, AM
   LOVE, JM
   MCALEER, MA
   PRINS, JB
   RODRIGUES, N
   LATHROP, M
   PRESSEY, A
   DELARATO, NH
   PETERSON, LB
   WICKER, LS
TI GENETIC-ANALYSIS OF AUTOIMMUNE TYPE-1 DIABETES-MELLITUS IN MICE
SO NATURE
LA English
DT Article
ID dna polymorphisms; nod mouse; nonobese; insulitis; expression; prevention; linkage; heterogeneity; recombination; construction
AB Two genes, Idd-3 and Idd-4, that influence the onset of autoimmune type 1 diabetes in the nonobese diabetic mouse have been located on chromosomes 3 and 11, outside the chromosome 17 major histocompatibility complex.  A genetic map of the mouse genome, analysed using the polymerase chain reaction, has been assembled specifically for the study.  On the basis of comparative maps of the mouse and human genomes, the homologue of Idd-3 may reside on human chromosomes 1 or 4 and Idd-4 on chromosome 17.
C1 CLIN RES CTR,HARROW HA1 3UJ,MIDDX,ENGLAND.
   CTR ETUD POLYMORPHISME HUMAINE,F-75010 PARIS,FRANCE.
   MERCK SHARP & DOHME LTD,DEPT CELLULAR & MOLEC PHARMACOL,RAHWAY,NJ 07065.
   MERCK SHARP & DOHME LTD,AUTOIMMUNE DIS RES,RAHWAY,NJ 07065.
C3 Merck & Company; Merck & Company
RP TODD, JA (corresponding author), JOHN RADCLIFFE HOSP,NUFFIELD DEPT SURG,OXFORD OX3 9DU,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 50
TC 510
Z9 531
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 542
EP 547
DI 10.1038/351542a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400049
PM 1675432
DA 2026-03-10
ER

PT J
AU KUDRASS, HR
   ERLENKEUSER, H
   VOLLBRECHT, R
   WEISS, W
AF KUDRASS, HR
   ERLENKEUSER, H
   VOLLBRECHT, R
   WEISS, W
TI GLOBAL NATURE OF THE YOUNGER DRYAS COOLING EVENT INFERRED FROM OXYGEN ISOTOPE DATA FROM SULU SEA CORES
SO NATURE
LA English
DT Article
ID vostok ice core; last deglaciation; abrupt termination; ocean circulation; record; pacific; mexico; level; gulf; co2
AB THE Younger Dryas, an approximately 1,000-year-long return to near-glacial conditions, interrupted the glacial/Holocene climate transition during which most of the Northern Hemisphere ice sheets melted.  Evidence for the Younger Dryas event has been found mainly in sediments from the North Atlantic Ocean and northwest Europe, and this has led to the idea that the event was caused by an injection of meltwater into the North Atlantic Ocean 1-3.  This model, however, has been recently questioned in the light of coral-reef data on the rate of sea level changes during this transition 4.  Here we present high-resolution oxygen isotope records from benthic and planktonic foraminifera from two radio-carbon-dated cores in the Sulu Sea, showing that the Younger Dryas occurred synchronously in the surface and deep waters of the Sulu Sea and the northern Atlantic Ocean.  By combining our results with other palaeoclimate data, we suggest that the Younger Dryas event was a global phenomenon, and we believe it to have been caused by low atmospheric CO2 concentrations.
C1 INST REINE & ANGEW KERNPHYS,W-2300 KIEL,GERMANY.
   INST GEOL & PALAONTOL,W-3400 GOTTINGEN,GERMANY.
RP KUDRASS, HR (corresponding author), BUNDESANSTALT GEOWISSENSCH & ROHSTOFFE,STILLEWEG 2,W-3000 HANNOVER 51,GERMANY.
NR 31
TC 120
Z9 124
U1 3
U2 41
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 406
EP 409
DI 10.1038/349406a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400047
DA 2026-03-10
ER

PT J
AU INGHAM, PW
   TAYLOR, AM
   NAKANO, Y
AF INGHAM, PW
   TAYLOR, AM
   NAKANO, Y
TI ROLE OF THE DROSOPHILA PATCHED GENE IN POSITIONAL SIGNALING
SO NATURE
LA English
DT Article
ID segment polarity gene; spatial-distribution; embryonic pattern; fushi-tarazu; protein; expression; wingless; blastoderm; region
AB AFTER cellularization of the Drosophila embryo, positional differences within each primordial segment are maintained and elaborated by processes that require cell interactions. The best-documented examples 1,2 of such intercellular signalling are the mutual interactions between neighbouring cells expressing the homeodomain protein engrailed 3 and the secreted glycoprotein encoded by wingless 4, the Drosophila homologue of the murine Wnt-1 gene 5. Little is known about the molecular basis of these signalling mechanisms but the activities of several other genes, notably patched and hedgehog, have been implicated in the process 1,2. Here we show that the role of patched in positional signalling is permissive rather than instructive, its activity being required to suppress wingless transcription in cells predisposed to express the latter. According to this view, expression of wingless is normally maintained only in those cells receiving an extrinsic signal, encoded by hedgehog, that antagonizes the repressive activity of patched. We suggest that the patched protein may itself be the receptor for this signal, implying that this is an unusual mechanism of ligand-dependent receptor inactivation.
RP INGHAM, PW (corresponding author), IMPERIAL CANC RES FUND, DEPT ZOOL, DEV BIOL UNIT, MOLEC EMBRYOL LAB, S PARKS RD, OXFORD OX1 3PS, ENGLAND.
NR 22
TC 391
Z9 484
U1 0
U2 32
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 184
EP 187
DI 10.1038/353184a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100059
PM 1653906
DA 2026-03-10
ER

PT J
AU CALVERT, SE
   KARLIN, RE
   TOOLIN, LJ
   DONAHUE, DJ
   SOUTHON, JR
   VOGEL, JS
AF CALVERT, SE
   KARLIN, RE
   TOOLIN, LJ
   DONAHUE, DJ
   SOUTHON, JR
   VOGEL, JS
TI LOW ORGANIC-CARBON ACCUMULATION RATES IN BLACK-SEA SEDIMENTS
SO NATURE
LA English
DT Article
ID accelerator; preservation; reduction; matter
AB THE Black Sea, the world's largest anoxic marine basin, is frequently used as a modern analogue for the formation of organic-rich sediments and carbonaceous rocks 1-3, on the widely held assumption that anoxic conditions promote the preferential preservation of organic matter in sediments.  Data for testing this hypothesis have so far been equivocal 4-7, but here we use radiocarbon ages obtained using accelerator mass spectrometry for the organic fraction of recent Black Sea sediments to estimate the organic carbon accumulation rates.  These range from 0.69 to 2.09 g C m-2 yr-1 and are significantly lower than earlier estimates based on varve counting 6.  Depending on the value taken for the rate of primary production in the Black Sea 4,8, between 0.7 and 2.1% of the organic carbon is preserved in the bottom sediments.  When compared with carbon accumulation rates in equivalent oxygenated environments 9, these results indicate that the modern Black Sea is not a site of anomalously high organic carbon accumulation.  This suggests that anoxic conditions in the water column may not be a prerequisite for the preservation of organic matter in marine sediments, and that models of the origin of carbonaceous facies in the geological record may therefore need to be modified.
C1 UNIV NEVADA,MACKAY SCH MINES,RENO,NV 89557.
   UNIV ARIZONA,NATL SCI FDN,ARIZONA AMS FACIL,TUCSON,AZ 85721.
   SIMON FRASER UNIV,DEPT ARCHAEOL,BURNABY V5A 1S6,BC,CANADA.
C3 Nevada System of Higher Education (NSHE); University of Nevada Reno; National Science Foundation (NSF); University of Arizona; Simon Fraser University
RP CALVERT, SE (corresponding author), UNIV BRITISH COLUMBIA,DEPT OCEANOG,VANCOUVER V6T 1W5,BC,CANADA.
NR 29
TC 114
Z9 117
U1 0
U2 30
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 692
EP 695
DI 10.1038/350692a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000055
DA 2026-03-10
ER

PT J
AU TANAKA, N
   TUREKIAN, KK
AF TANAKA, N
   TUREKIAN, KK
TI USE OF COSMOGENIC S-35 TO DETERMINE THE RATES OF REMOVAL OF ATMOSPHERIC SO2
SO NATURE
LA English
DT Article
ID ray produced s-38; insitu measurement; sulfur-dioxide; lifetimes; pb-210; troposphere; sulfate; aerosol; be-7
AB GASEOUS sulphur dioxide supplied to the atmosphere is removed principally by three processes: direct scavenging in precipitation, oxidation to aerosol sulphate with subsequent deposition by vertical and horizontal precipitation, and 'dry' deposition, primarily on the surface of vegetation. The rates of these removal processes, which vary with environmental conditions, must be known in order to understand the fate of SO2 and the concentration and distribution of aerosol sulphate 1-3. The latter is thought to play a part in the heat balance of the lower troposphere 4, and is thus relevant to the issue of global warming. Approaches to this problem using field observations 5,6 have not given consistent or uncontested results. We report here the use of cosmogenic S-35 (half-life 87.2 days) as a way of determining the time constants for oxidation, in-cloud scavenging and aerosol deposition. Our method involves determining S-35 levels in gaseous SO2, aerosol sulphate and precipitation. If these seasonally and regionally variable time constants can be applied to terrestrially produced SO2, S-35 measurements could provide an independent method for studying the fate Of SO2 in the atmosphere as a function of time and place.
RP TANAKA, N (corresponding author), YALE UNIV,DEPT GEOL & GEOPHYS,POB 6666,NEW HAVEN,CT 06511, USA.
NR 19
TC 39
Z9 42
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 226
EP 228
DI 10.1038/352226a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500060
DA 2026-03-10
ER

PT J
AU BOSS, AP
AF BOSS, AP
TI FORMATION OF HIERARCHICAL MULTIPLE PROTOSTELLAR CORES
SO NATURE
LA English
DT Article
ID dark clouds; dense cores; molecular clouds; evolution; systems; star; fragmentation; discovery; stability; binary
AB BINARY pre-main-sequence stars 1,2 seem to occur as frequently as binary main-sequence stars 3,4; triple pre-main-sequence star systems have also been detected 5, and hierarchical main-sequence multiple stars continue to be identified 6. (Hierarchical systems contain both closely spaced stars and stars orbiting at much greater distances.)  These observations suggest that essentially all binary stars were formed before the main-sequence phase of evolution.  The detection of a number of binary young stellar objects 7,8 seems to indicate that binary formation must occur no later than the protostellar phase (further observations are needed to establish if this is the case for multiple star systems).  Here I describe numerical hydrodynamical calculations showing that stable hierarchical systems of multiple protostellar cores can form through gravitationally driven fragmentation during the collapse of an isolated gas cloud, suggesting that the hierarchical systems observed may be the result of the hydrodynamical collapse of rapidly rotating clouds.
RP BOSS, AP (corresponding author), CARNEGIE INST WASHINGTON,DEPT TERR MAGNETISM,5241 BROAD BRANCH RD NW,WASHINGTON,DC 20015, USA.
NR 31
TC 74
Z9 75
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 298
EP 300
DI 10.1038/351298a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600052
DA 2026-03-10
ER

PT J
AU DAVIDSON, DR
   CRAWLEY, A
   HILL, RE
   TICKLE, C
AF DAVIDSON, DR
   CRAWLEY, A
   HILL, RE
   TICKLE, C
TI POSITION-DEPENDENT EXPRESSION OF 2 RELATED HOMEOBOX GENES IN DEVELOPING VERTEBRATE LIMBS
SO NATURE
LA English
DT Article
ID chick wing bud; pattern-formation; polarizing region; retinoic acid; mouse; drosophila
AB MANY genes that control pattern formation in insects contain a conserved homeobox region which encodes a domain involved in DNA binding 1.  One approach to understanding pattern formation in vertebrates is to examine the role of homeobox-containing genes in the developing limb 2.  Two such genes, Hox-7.1 and Hox-8.1, are expressed in distal mesoderm, but not in the proximal core, of mouse forelimb (refs 3,4, and D.R.D., manuscript in preparation). The proximodistal cartilage pattern in the chick wing is progressively determined in the distal mesoderm, which is maintained as a 'progress zone' by the overlying apical ectodermal ridge 5.  Indeed, proximal cells are reprogrammed to form distal structures when placed in the progress zone 6 and we therefore expect that genes involved in controlling limb pattern should be activated in such grafts. We tested this requirement for Hox-7.1 and Hox-8.1 in mouse limb mesoderm placed in chick wing buds. Our results reported here indicate that both genes are rapidly activated by a signal from the apical ectoderm. These properties, taken with the DNA-binding properties of the homeodomain, strongly suggest that Hox-7.1 and Hox-8.1 have fundamental roles in limb-pattern formation.
C1 UNIV COLL & MIDDLESEX SCH MED,DEPT ANAT & DEV BIOL,LONDON W1P 6DB,ENGLAND.
C3 University of London; University College London
RP DAVIDSON, DR (corresponding author), WESTERN GEN HOSP,MRC,HUMAN GENET UNIT,DEV GENET GRP,EDINBURGH EH4 2XU,MIDLOTHIAN,SCOTLAND.
NR 20
TC 191
Z9 198
U1 1
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 429
EP 431
DI 10.1038/352429a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600064
PM 1677742
DA 2026-03-10
ER

PT J
AU AHLBERG, PE
AF AHLBERG, PE
TI TETRAPOD OR NEAR-TETRAPOD FOSSILS FROM THE UPPER DEVONIAN OF SCOTLAND
SO NATURE
LA English
DT Article
ID greererpeton-burkemorani romer; morphology; australia; evolution; victoria; fish
AB SINCE 1932, the earliest known undisputed tetrapods have been of uppermost Famennian (late Upper Devonian) age 1-3. Although a probable tetrapod jaw has been described from the Lower Famennian 4, and tetrapod tracks of supposedly Frasnian 5 (and possibly earlier 6) age are known, no fossil limb material older than the latest Famennian has been discovered. The 'panderichthyids' Panderichthys 7 and Elpistostege 8 from the Lower Frasnian (early Upper Devonian) are regarded by some 8-10 as the closest known sister group of tetrapods, but Panderichthys has paired fins rather than limbs 11. Here, I describe a hitherto unrecognized tibia from the Upper Frasnian (middle Upper Devonian) site of Scat Craig, near Elgin, Scotland 12-14, collected during the nineteenth century, which extends the fossil record of the tetrapod-type hind limb by roughly seven million years 15. Other isolated bones from the same locality also show tetrapod characteristics. The tibia, a humerus and some incomplete jaws are discussed below, but a complete description of the material is in preparation.
RP AHLBERG, PE (corresponding author), UNIV OXFORD,DEPT ZOOL,S PARKS RD,OXFORD OX1 3PS,ENGLAND.
NR 36
TC 69
Z9 75
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 298
EP 301
DI 10.1038/354298a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400045
DA 2026-03-10
ER

PT J
AU MORI, Y
   FRIEDRICH, T
   KIM, MS
   MIKAMI, A
   NAKAI, J
   RUTH, P
   BOSSE, E
   HOFMANN, F
   FLOCKERZI, V
   FURUICHI, T
   MIKOSHIBA, K
   IMOTO, K
   TANABE, T
   NUMA, S
AF MORI, Y
   FRIEDRICH, T
   KIM, MS
   MIKAMI, A
   NAKAI, J
   RUTH, P
   BOSSE, E
   HOFMANN, F
   FLOCKERZI, V
   FURUICHI, T
   MIKOSHIBA, K
   IMOTO, K
   TANABE, T
   NUMA, S
TI PRIMARY STRUCTURE AND FUNCTIONAL EXPRESSION FROM COMPLEMENTARY-DNA OF A BRAIN CALCIUM-CHANNEL
SO NATURE
LA English
DT Article
ID skeletal-muscle; dihydropyridine receptor; cerebellar slices; messenger-rnas; mutant mice; alpha-1-subunit; modulation; currents; sequence; neurons
AB The primary structure of a voltage-dependent calcium channel from rabbit brain has been deduced by cloning and sequencing the complementary DNA. Calcium channel activity expressed from the cDNA is dramatically increased by coexpression of the alpha-2 and beta-subunits, known to be associated with the dihydropyridine receptor. This channel is a high voltage-activated calcium channel that is insensitive both to nifedipine and to omega-conotoxin. We suggest that it is expressed predominantly in cerebellar Purkinje cells and granule cells.
C1 KYOTO UNIV, FAC MED, DEPT MED CHEM, KYOTO 606, JAPAN.
   KYOTO UNIV, FAC MED, DEPT MOLEC GENET, KYOTO 606, JAPAN.
   UNIV SAARLAND, FAK MED, INST MED BIOCHEM, W-6650 HOMBURG, GERMANY.
   NATL INST BASIC BIOL, DIV BEHAV & NEUROBIOL, OKAZAKI, AICHI 444, JAPAN.
   OSAKA UNIV, INST PROT RES, DIV REGULAT MACROMOLEC FUNCT, SUITA, OSAKA 565, JAPAN.
C3 Kyoto University; Kyoto University; Saarland University; National Institutes of Natural Sciences (NINS) - Japan; National Institute for Basic Biology (NIBB); University of Osaka
NR 37
TC 780
Z9 850
U1 0
U2 14
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 398
EP 402
DI 10.1038/350398a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200040
PM 1849233
DA 2026-03-10
ER

PT J
AU RALSTON, R
AF RALSTON, R
TI COMPLEMENTATION OF TRANSFORMING DOMAINS IN E1A/MYC CHIMERAS
SO NATURE
LA English
DT Article
ID adenovirus e1a proteins; c-myc; large-t; oncogenes; products; regions; gene; cells; e7
AB THE myc oncogene is functionally similar to adenovirus E1a in its ability to collaborate with activated ras oncogenes to transform primary fibroblasts 1,2. The transforming functions of E1a and myc have been mapped to two distinct regions in each protein 3,4. I investigated the functional similarities between E1a and myc by constructing E1a/myc chimaeras to discover whether the individual transforming domains of E1a could complement individual myc-transforming domains. Transformation assays in rat embryo fibroblasts demonstrated that the N-terminal transforming domain of E1a (CR1; ref. 5) could complement the C-terminal transforming domain of myc in cis, and that the reciprocal chimaera (N-terminal myc/C-terminal E1a) was also active. Chimaeras constructed using domains from transformation-defective mutants of either E1a or myc were inactive, indicating that both E1a and myc domains contribute to function. These experiments suggest that transformation by myc and E1a may involve interactions with common substrates.
RP RALSTON, R (corresponding author), CHIRON CORP, 4560 HORTON ST, EMERYVILLE, CA 94608 USA.
NR 24
TC 23
Z9 23
U1 0
U2 0
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 866
EP 868
DI 10.1038/353866a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200067
PM 1834947
DA 2026-03-10
ER

PT J
AU OWENS, NJP
   LAW, CS
   MANTOURA, RFC
   BURKILL, PH
   LLEWELLYN, CA
AF OWENS, NJP
   LAW, CS
   MANTOURA, RFC
   BURKILL, PH
   LLEWELLYN, CA
TI METHANE FLUX TO THE ATMOSPHERE FROM THE ARABIAN SEA
SO NATURE
LA English
DT Article
ID surface waters; deep ocean; atlantic; hydrogen
AB ATMOSPHERIC concentrations of methane, an important green-house gas, have increased significantly over the past few decades 1,2. Although attention has been focused on anthropogenic sources, data from ice cores show that large changes in atmospheric methane concentrations have occurred over glacial-interglacial time scales, indicating that there is significant variability in natural methane fluxes 3,4 . The surface waters of the oceans are often supersaturated with methane, which implies that the oceans are a net source, although their contribution to the global methane budget is small relative to other sources 4. Here we report high concentrations of methane in the Arabian Sea, and calculate that the flux of methane to the atmosphere is up to five times greater than the previously reported average ocean flux. Methane production is associated with high phytoplankton biomass, which is closely coupled with the monsoon-driven upwelling of nutrient-rich water. We calculate that the Arabian Sea (representing 0.43% of the total surface area of the world's oceans) could account for between 1.3 and 133% of the current estimates of the open-ocean source of methane. Our results do not alter the view that the oceans are a relatively minor source of atmospheric methane, but the magnitude of the methane fluxes from the Arabian Sea and the link with the monsoon suggest that this region may be particularly sensitive to climate change, with a greater potential for feedback responses than its surface area might suggest.
RP OWENS, NJP (corresponding author), PLYMOUTH MARINE LAB,PROSPECT PL,HOE,PLYMOUTH PL1 3DH,ENGLAND.
NR 27
TC 97
Z9 101
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 293
EP 296
DI 10.1038/354293a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400043
DA 2026-03-10
ER

PT J
AU AHARONI, R
   TEITELBAUM, D
   ARNON, R
   PURI, J
AF AHARONI, R
   TEITELBAUM, D
   ARNON, R
   PURI, J
TI IMMUNOMODULATION OF EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS BY ANTIBODIES TO THE ANTIGEN-IA COMPLEX
SO NATURE
LA English
DT Article
ID myelin basic-protein; autoimmune encephalomyelitis; class-ii; t-cells; histocompatibility molecules; immune-response; peptide; binding; vaccination; recognition
AB AUTOIMMUNE diseases occur when T lymphocytes become activated on recognizing self antigen linked to the autologous class II molecule of the major histocompatibility complex (MHC) 1,2. The resulting complex of antigen MHC T-cell receptor could be a target for treatment of autoimmune diseases. Studies in which each component is blocked separately 3-10 might be limited by interference in non-relevant immune responses that either use the same set of T-cell-receptor V gene segments or are linked to the same MHC. We report here an attack by a specific antibody on the unique antigenic site formed by the binding of two components of the trimolecular complex, the autoantigen bound to the self MHC 11-14. We tested its effect in experimental allergic encephalomyelitis, an acute neurological autoimmune disease which is widely regarded as a model for autoimmune disorders 15-17 and which is mediated by CD4+ T cells recognizing myelin basic protein (BP), or its peptides, in association with self Ia 18,19. We made monoclonal antibodies which bound only the complex of BP and I-A(s). These antibodies blocked the proliferative response in vitro to the encephalitogenic determinant of BP and reduced the response to intact BP, without affecting the response to a nonrelevant antigen-purified protein derivative of tuberculin presented on syngeneic macrophages. They also inhibited experimental allergic encephalomyelitis in H-2s mice. Hence, antibodies directed specifically to the autoantigen-Ia complex, may offer a highly selective and effective treatment in autoimmune diseases.
C1 WEIZMANN INST SCI, DEPT CHEM IMMUNOL, IL-76100 REHOVOT, ISRAEL.
C3 Weizmann Institute of Science
NR 25
TC 92
Z9 112
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 147
EP 150
DI 10.1038/351147a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500051
PM 1709449
DA 2026-03-10
ER

PT J
AU BARASCH, J
   KISS, B
   PRINCE, A
   SAIMAN, L
   GRUENERT, D
   ALAWQATI, Q
AF BARASCH, J
   KISS, B
   PRINCE, A
   SAIMAN, L
   GRUENERT, D
   ALAWQATI, Q
TI DEFECTIVE ACIDIFICATION OF INTRACELLULAR ORGANELLES IN CYSTIC-FIBROSIS
SO NATURE
LA English
DT Article
ID dependent protein-kinase; chloride conductance; golgi-apparatus; rat-liver; glycoproteins; gangliosides; biosynthesis; fibroblasts; epithelium; channels
AB THE phenotype of cystic fibrosis (CF) includes abnormalities in transepithelial transport of Cl- (refs 1-5), decreased sialylation and increased sulphation and fucosylation of glycoproteins 6-9, and lung colonization with Pseudomonas. It is not apparent how these abnormalities are interrelated, nor how they result from loss of function of the CF gene-encoded transmembrane regulator (CFTR) 10. We have previously shown that that the pH of a secretory granule is regulated by the vesicular conductance for Cl- (ref. 11). Here we find defective acidification in CF cells of the trans-Golgi/trans-Golgi network, of prelysosomes and of endosomes as a result of diminished Cl- conductance. Sialylation of proteins and lipids is reduced and ligand traffic altered. These abnormalities can result from defective acidification because vacuolar pH regulates glycoprotein processing and ligand transport. The CF phenotype is similar to that of alkalinized cells 12 and acidification-defective mutatants 13.
C1 COLUMBIA UNIV COLL PHYS & SURG,DEPT PHYSIOL,NEW YORK,NY 10032.
   COLUMBIA UNIV COLL PHYS & SURG,DEPT PEDIAT,NEW YORK,NY 10032.
   UNIV CALIF SAN FRANCISCO,CYST FIBROSIS RES CTR,SAN FRANCISCO,CA 94143.
C3 Columbia University; Columbia University; University of California System; University of California San Francisco
RP BARASCH, J (corresponding author), COLUMBIA UNIV COLL PHYS & SURG,DEPT MED,NEW YORK,NY 10032, USA.
NR 36
TC 472
Z9 494
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 70
EP 73
DI 10.1038/352070a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800073
PM 1712081
DA 2026-03-10
ER

PT J
AU SMEAL, T
   BINETRUY, B
   MERCOLA, DA
   BIRRER, M
   KARIN, M
AF SMEAL, T
   BINETRUY, B
   MERCOLA, DA
   BIRRER, M
   KARIN, M
TI ONCOGENIC AND TRANSCRIPTIONAL COOPERATION WITH HA-RAS REQUIRES PHOSPHORYLATION OF C-JUN ON SERINE-63 AND SERINE-73
SO NATURE
LA English
DT Article
ID expression; gene; pea1
AB RECENT advances indicate a link between tumour promoters, transformation, and AP-1 activity 1. Protein kinase C activation increases AP-1 DNA-binding activity independently of new protein synthesis 2,3. AP-1 is also stimulated by transforming oncoproteins and growth factors 4-6. These proteins are thought to participate in a signalling cascade affecting the nuclear AP-1 complex composed of the Jun and Fos proteins 1,7,8. Because c-Jun is the most potent transactivator in the AP-1 complex 9-12 and is elevated in Ha-ras-transformed cells, in which c-Fos is downregulated 13,14, we focused on it as a potential target. c-Jun could convert input from an oncogenic signalling cascade into changes in gene expression. Indeed, transformation of rat embryo fibroblasts by c-Jun requires an intact transcriptional activation domain 15 and cooperation with oncogenic Ha-ras 16. Expression of oncogenic Ha-ras augments transactivation by c-Jun and stimulates its phosphorylation 14. Here we describe the mapping of the Ha-ras-responsive phosphorylation sites to serines 63 and 73 of c-Jun. Site-directed mutagenesis indicates that phosphorylation of these serines is essential for stimulation of c-Jun activity and for cooperation with Ha-ras in ocogenic transformation.
C1 UNIV CALIF SAN DIEGO, SCH MED, CTR MOLEC GENET, DEPT PHARMACOL, LA JOLLA, CA 92093 USA.
   NCI, DIV CANC PREVENT & CONTROL, BETHESDA, MD 20814 USA.
   UNIV CALIF SAN DIEGO, SCH MED, CTR MOLEC GENET, DEPT PATHOL, LA JOLLA, CA 92093 USA.
   UNIV CALIF SAN DIEGO, SCH MED, CTR MOLEC GENET, DEPT BIOL, LA JOLLA, CA 92093 USA.
C3 University of California System; University of California San Diego; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); University of California System; University of California San Diego; University of California System; University of California San Diego
RP KARIN, M (corresponding author), UNIV CALIF SAN DIEGO, SCH MED, CTR MOLEC GENET, DEPT PHARMACOL, LA JOLLA, CA 92093 USA.
NR 26
TC 787
Z9 856
U1 0
U2 14
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 494
EP 496
DI 10.1038/354494a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800065
PM 1749429
DA 2026-03-10
ER

PT J
AU LEWIS, A
   LIEBERMAN, K
AF LEWIS, A
   LIEBERMAN, K
TI NEAR-FIELD OPTICAL IMAGING WITH A NON-EVANESCENTLY EXCITED HIGH-BRIGHTNESS LIGHT-SOURCE OF SUBWAVELENGTH DIMENSIONS
SO NATURE
LA English
DT Article
ID spatial-resolution; microscopy; apertures
AB NEAR-field optics involves scanning a spot of light, of dimensions smaller than a wavelength, across the surface of a sample at a distance small enough (a few hundred angstroms) that far-field diffraction effects do not occur 1,2.  In principle this method should generate an image with a resolution determined principally by the dimensions of the spot of light and not limited by the wavelength 3. Although near-field imaging was first proposed in 1928 4,5, efficient implementations that overcome the problem of large evanescent losses in passing light through a sub-wavelength aperture have not been previously realized. Here we present a technique that creates a point of sub-wavelength light without associated evanescent losses in its excitation while achieving the advantage of the exponential increase in intensity that occurs within the near-field 3.  The sub-wavelength light source is provided by a micropipette coated with a metal and filled with a fluorescent dye embedded in a plastic matrix. The instrument we describe combines the potential for near-field microscopy with the characteristics of a conventional far-field light microscope. Images with overlapping resolutions can be obtained having magnifications that range from a few hundred with the conventional microscope to magnifications, in the near-field mode, of tens of thousands that are of the order normally associated with scanning electron microscopy. Such imaging with light can be achieved even with fluorescence, under ambient conditions and without the destructive sample preparation and beam damage that is characteristic of electron microscopy.
RP LEWIS, A (corresponding author), HEBREW UNIV JERUSALEM,DIV APPL PHYS,JERUSALEM,ISRAEL.
NR 19
TC 91
Z9 96
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 214
EP 216
DI 10.1038/354214a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800043
DA 2026-03-10
ER

PT J
AU AYERS, GP
   GRAS, JL
AF AYERS, GP
   GRAS, JL
TI SEASONAL RELATIONSHIP BETWEEN CLOUD CONDENSATION NUCLEI AND AEROSOL METHANESULFONATE IN MARINE AIR
SO NATURE
LA English
DT Article
ID cape grim; southern
AB CHARLSON et al. 1 have suggested that cloud-droplet concentrations in remote marine regions might be indirectly controlled by dimethylsulphide (DMS) emissions from marine phytoplankton. Attempts to test the hypothesis that variations in DMS emissions lead to corresponding variations in marine aerosol composition and hence concentrations of cloud condensation nuclei (CCN) have so far proved inconclusive, primarily because of the inherent variability of the atmospheric species involved over the timescales typical of individual field measurements 2.  Here we present nine years of data from Cape Grim (41-degrees-S) which show that there is a significant seasonal relationship between cloud condensation nuclei and methanesulphonate, an easily sampled oxidation product of DMS, but the relationship is nonlinear. These results confirm that DMS emissions strongly influence CCN concentrations, but we note that at low concentrations of methanesulphonate, there are indications that there may be another source of CCN, apart from DMS.
RP AYERS, GP (corresponding author), CSIRO,DIV ATMOSPHER RES,PRIVATE BAG 1,MORDIALLOC 3195,AUSTRALIA.
NR 14
TC 251
Z9 275
U1 0
U2 61
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 834
EP 835
DI 10.1038/353834a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200055
DA 2026-03-10
ER

PT J
AU NONET, ML
   MEYER, BJ
AF NONET, ML
   MEYER, BJ
TI EARLY ASPECTS OF CAENORHABDITIS-ELEGANS SEX DETERMINATION AND DOSAGE COMPENSATION ARE REGULATED BY A ZINC-FINGER PROTEIN
SO NATURE
LA English
DT Article
ID x-chromosome dosage; c-elegans; region; genes; dna
AB THE sdc-1 gene acts at an early step in the regulatory hierarchy that controls the choice of sexual fate in Caenorhabditis elegans.  It functions at a point before the control of sex determination and X-chromosome dosage compensation diverge.  Here we report that sdc-1 encodes a protein of 1,203 amino acids containing seven zinc fingers.  This protein motif in combination with other genetic and molecular information suggests that sdc-1 is likely to function as an embryonic transcription factor regulating downstream genes involved specifically in the sex determination and dosage compensation pathways, or regulating other genes involved in the coordinate control of both processes.  These results enhance our general understanding of sex determination strategies, which are already known to involve transcriptional regulation 1 and alternative RNA splicing 2,3 in Drosophila melanogaster, DNA rearrangements in Saccharomyces cerevisiae 4, and transcriptional regulation in mammals 5,6.
C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720.
C3 University of California System; University of California Berkeley
FU NIGMS NIH HHS [R01 GM030702] Funding Source: Medline
NR 35
TC 55
Z9 69
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 65
EP 68
DI 10.1038/351065a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300061
PM 2027384
DA 2026-03-10
ER

PT J
AU SUTTON, M
   MOCHRIE, SGJ
   GREYTAK, T
   NAGLER, SE
   BERMAN, LE
   HELD, GA
   STEPHENSON, GB
AF SUTTON, M
   MOCHRIE, SGJ
   GREYTAK, T
   NAGLER, SE
   BERMAN, LE
   HELD, GA
   STEPHENSON, GB
TI OBSERVATION OF SPECKLE BY DIFFRACTION WITH COHERENT X-RAYS
SO NATURE
LA English
DT Article
AB REFLECTED light from a coherent light source such as a laser shows a graininess known as speckle. In general, a speckle pattern is produced whenever randomly distributed regions of a material introduce different phase shifts into the scattering of coherent incident light. If the arrangement of the regions evolves with time, the speckle pattern will also change. Observation of the intensity fluctuations at a single point in the speckle pattern provides a direct measure of the time correlation function of the inhomogeneity. This leads to a technique 1,2, alternatively called light-beating spectroscopy, dynamic light scattering or intensity fluctuation spectroscopy, which has been widely used with visible light to study processes such as critical fluctuations near phase transitions in fluids and the diffusion of particles in liquids. But it is not possible to study processes involving length scales less than about 200 nm, or those in opaque materials, using visible light. If intensity fluctuation spectroscopy could be carried out using coherent X-rays, however, one could probe the dynamics of processes involving atomic length scales in a wide range of materials. Here we show that by using a high-brilliance X-ray source it should be possible to perform this type of measurement using radiation of wavelength approximately 0.15 nm. Specifically, we have observed a speckle pattern in the diffraction of coherent X-rays from randomly arranged antiphase domains in a single crystal of the binary alloy Cu3Au.
C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139.
   UNIV FLORIDA,DEPT PHYS,GAINESVILLE,FL 32611.
   BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973.
   IBM CORP,THOMAS J WATSON RES CTR,DIV RES,YORKTOWN HTS,NY 10598.
C3 Massachusetts Institute of Technology (MIT); State University System of Florida; University of Florida; United States Department of Energy (DOE); Brookhaven National Laboratory; State University of New York (SUNY) System; International Business Machines (IBM); IBM USA
RP SUTTON, M (corresponding author), MCGILL UNIV,CTR PHYS MAT,DEPT PHYS,MONTREAL H3A 2T8,QUEBEC,CANADA.
NR 10
TC 330
Z9 369
U1 0
U2 88
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 608
EP 610
DI 10.1038/352608a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100050
DA 2026-03-10
ER

PT J
AU NARDELLI, J
   GIBSON, TJ
   VESQUE, C
   CHARNAY, P
AF NARDELLI, J
   GIBSON, TJ
   VESQUE, C
   CHARNAY, P
TI BASE SEQUENCE DISCRIMINATION BY ZINC-FINGER DNA-BINDING DOMAINS
SO NATURE
LA English
DT Article
ID transcription factor tfiiia; repressor-operator interactions; rna-polymerase; nucleic-acids; factor-iiia; proteins; expression; gene; recognition; resolution
AB Zinc fingers 1,2 constitute important eukaryotic DNA-binding domains, being present in many transcription factors 3-5.  The Cys2/His2 zinc-finger class has conserved motifs of 28-30 amino acids which are usually present as tandem repeats 1,2.  The structure of a Cys2/His2 zinc finger has been determined by nuclear magnetic resonance 6, but details of its interaction with DNA were not established.  Here we identify amino acids governing DNA-binding specificity using in vitro directed mutagenesis guided by similarities between the zinc fingers of transcription factors Sp1 (ref. 7) and Krox-20 (ref. 8).  Krox-20 is a serum-inducible transcription activator 8,9 which is possibly involved in the regulation of hindbrain development 10; it contains three zinc fingers similar to those of Ap1 (refs 7, 8, 11) and binds to a 9-base-pair target sequence which is related to that of Sp1 (ref. 9). Our results show that each finger spans three nucleotides and indicate two positions in Krox-20 zinc fingers that are important for base-pair selectivity.  Modelling with molecular graphics suggests that these residues could bind directly with the bases and that other amino acid-base contracts are also possible.
C1 EUROPEAN MOLEC BIOL LAB,W-6900 HEIDELBERG,GERMANY.
C3 European Molecular Biology Laboratory (EMBL)
RP NARDELLI, J (corresponding author), ECOLE POLYTECH,GENET MOLEC LAB,CNRS,D1302,46 RUE ULM,F-75230 PARIS 05,FRANCE.
NR 30
TC 249
Z9 292
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 175
EP 178
DI 10.1038/349175a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800065
PM 1898772
DA 2026-03-10
ER

PT J
AU UCHIDA, Y
   FUKUI, Y
   MINOSHIMA, Y
   MIZUNO, A
   IWATA, T
   TAKABA, H
AF UCHIDA, Y
   FUKUI, Y
   MINOSHIMA, Y
   MIZUNO, A
   IWATA, T
   TAKABA, H
TI EVIDENCE FOR A ROTATING HELICAL FILAMENT IN L1641, PART OF THE ORION CLOUD COMPLEX
SO NATURE
LA English
DT Article
AB Interstellar cloud structures, typically 10-30 pc long and 3-5 pc wide, are often seen extending outwards from dense clouds that show marked enhancement of star formation within them.  We have used the Nagoya 4-m radiotelescope to study one such 'streamer', L1641, a part of the giant molecular-cloud complex in Orion, lying south of the Kleinmann-Low (KL) nebula.  Using the 110-GHz line of CO-13 (J = 1-0), we have obtained intensity and velocity data, and find within the streamer a dense filament with a helical structure, spinning in the same sense as the gas in the Orion KL region.  We propose a model for this structure in which the streamer, through the action of the interstellar magnetic field, acts as an angular-momentum drain on the Orion KL region, allowing it to collapse.  In this model, the approximately 30-pc-long streamer is essential to the formation of the cloud, as well as the formation of stars within the dense cloud.
C1 NAGOYA UNIV,DEPT ASTROPHYS,CHIKUSA KU,NAGOYA 46401,JAPAN.
   COMMUN RES LABS,KASHIMA,IBARAKI 314,JAPAN.
C3 Nagoya University; National Institute of Information & Communications Technology (NICT) - Japan
RP UCHIDA, Y (corresponding author), UNIV TOKYO,DEPT ASTRON,BUNKYO KU,TOKYO 113,JAPAN.
NR 10
TC 28
Z9 28
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 140
EP 142
DI 10.1038/349140a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800051
DA 2026-03-10
ER

PT J
AU WALSH, JJ
AF WALSH, JJ
TI IMPORTANCE OF CONTINENTAL MARGINS IN THE MARINE BIOGEOCHEMICAL CYCLING OF CARBON AND NITROGEN
SO NATURE
LA English
DT Article
ID organic-carbon; ocean; sea; variability; nitrate; waters; shelf; layer; flux; eddy
AB THE continental margins occupy less than 20% of the surface area of the world ocean, and it is widely assumed that they do not play a significant part in the oceanic biogeochemical cycles of carbon and nitrogen.  Data from 32 sediment-trap moorings, 16 in the deep sea and 16 on the continental slope 1, suggest that at an average depth of 2,650 m on the slope, the combined rain of surviving shelf and slope particles yields a mean carbon flux of 6.9 g C m-2 yr-1-about ten times that at the same average depth in the deep sea (0.8 g C m-2 yr-1).  Because the area of the deep sea is about ten times greater than that of the continental slopes, using the sediment-trap data and assuming a carbon/nitrogen ratio of 5:1, the equivalent total particulate offshore nitrogen loss is 0.5 x 10(14) g N yr-1 at 2,650 m.  If these trap observations are generally representative of the oceans and continental margins, then the supply of dissolved nitrate to the overlying euphotic zones should also be similar.  Here I provide an independent estimate of the annual supply of onwelling nitrate from the deep sea to the shelves and find that it may balance the offshore flux of carbon, suggesting that the continental margins and deep sea are equally important in the carbon and nitrogen biogeochemical cycles.
RP WALSH, JJ (corresponding author), UNIV S FLORIDA,DEPT MARINE SCI,140 7TH AVE S,ST PETERSBURG,FL 33701, USA.
NR 38
TC 563
Z9 625
U1 5
U2 105
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 53
EP 55
DI 10.1038/350053a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300061
DA 2026-03-10
ER

PT J
AU SAKAI, T
   OHTANI, N
   MCGEE, TL
   ROBBINS, PD
   DRYJA, TP
AF SAKAI, T
   OHTANI, N
   MCGEE, TL
   ROBBINS, PD
   DRYJA, TP
TI ONCOGENIC GERM-LINE MUTATIONS IN SP1 AND ATF SITES IN THE HUMAN RETINOBLASTOMA GENE
SO NATURE
LA English
DT Article
ID dna-binding; reporter gene; expression; sequence; proteins
AB THE transcription of a eukaryotic gene is a consequence of intricate interactions between members of a set of transcription factors 1. We describe here evidence indicating that at least two distinct DNA-binding factors play an important part in the transcription of the human retinoblastoma gene (Rb). One of the factors reacts with a sequence overlapping with a potential Sp1 recognition sequence in the promoter region of the gene, the other with a nearby ATF recognition sequence. We have identified two naturally occurring point mutations in these recognition sequences that cause hereditary retinoblastoma. The nuclear factors do not bind to the mutant sequences. We infer that these nuclear factors are necessary for the expression of the Rb gene and the suppression of cancer.
C1 HARVARD UNIV,MASSACHUSETTS EYE & EAR INFIRM,SCH MED,DEPT OPHTHALMOL,BOSTON,MA 02114.
   UNIV PITTSBURGH,SCH MED,DEPT MOLEC GENET & BIOCHEM,PITTSBURGH,PA 15261.
C3 Harvard University; Harvard University Medical Affiliates; Massachusetts Eye & Ear Infirmary; Harvard Medical School; Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh
NR 14
TC 215
Z9 239
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 83
EP 90
DI 10.1038/353083a0
PG 8
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500065
PM 1881452
DA 2026-03-10
ER

PT J
AU PACHOLCZYK, T
   BLAKELY, RD
   AMARA, SG
AF PACHOLCZYK, T
   BLAKELY, RD
   AMARA, SG
TI EXPRESSION CLONING OF A COCAINE-SENSITIVE AND ANTIDEPRESSANT-SENSITIVE HUMAN NORADRENALINE TRANSPORTER
SO NATURE
LA English
DT Article
ID sk-n-sh; norepinephrine uptake; transient-expression; dna transfection; active uptake; cell-line; dopamine; receptor; storage; inhibition
AB AT most synapses, chemical signalling is terminated by a rapid reaccumulation of neurotransmitter into presynaptic terminals 1-5. Uptake systems for the biogenic amines are the initial site of action for therapeutic antidepressants and drugs such as cocaine and the amphetamines.  We have isolated a complementary DNA clone encoding a human noradrenaline transporter.  The cDNA sequence predicts a protein of 617 amino acids, with 12-13 highly hydrophobic regions compatible with membrane-spanning domains.  Expression of the cDNA clone in transfected HeLa cells indicates that noradrenaline transport activity is sodium-dependent and sensitive to selective noradrenaline transport inhibitors.  Transporter RNA is localized to the brainstem and the adrenal gland.  The predicted protein sequence demonstrates significant amino-acid identity with the Na+/gamma-aminobutyric acid transporter, thus identifying a new gene family for neurotransmitter transporter proteins.  Analysis of its structure and function may lead to structure-based drug design for the treatment of human depression and could help determine whether transporter abnormalities underlie affective disorders.
C1 YALE UNIV,PROGRAM NEUROSCI,NEW HAVEN,CT 06510.
C3 Yale University
RP PACHOLCZYK, T (corresponding author), YALE UNIV,SCH MED,HOWARD HUGHES MED INST,MOLEC NEUROBIOL SECT,333 CEDAR ST,NEW HAVEN,CT 06510, USA.
NR 37
TC 823
Z9 930
U1 0
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 350
EP 354
DI 10.1038/350350a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800096
PM 2008212
DA 2026-03-10
ER

PT J
AU ROGERS, DJ
   RANDOLPH, SE
AF ROGERS, DJ
   RANDOLPH, SE
TI MORTALITY-RATES AND POPULATION-DENSITY OF TSETSE-FLIES CORRELATED WITH SATELLITE IMAGERY
SO NATURE
LA English
DT Article
ID africa; glossina; kenya
AB TSETSE flies are a major constraint on animal production in about 10 million km 2 of Africa through their transmission of animal trypanosomiasis 1.  Up to 25 million people are at risk from human trypanosomiasis, or sleeping sickness 2.  Tsetse research has been concentrated on the factors that control the distribution and abundance of these vectors and the means by which their numbers can be reduced 3.  Eradication successes in some countries are insignificant compared with the continental scale of the problem and the long-term reduction in the area infested by tsetse has been negligible 4.  We report here that the mortality rates of tsetse from sites in both West and East Africa, the size of male and female tsetse (related to the mortality rate of the parental female population) along a north-south transect in West Africa, and the abundance of two species of tsetse over the northern half of Cote d'lvoire, are significantly correlated with data from meteorological satellites. This information could be used to predict both the mortality rate and the abundance (key determinants of disease transmission potential) of tsetse over very large areas of the continent and to produce maps of high risk areas of disease transmission for the African trypanosomiases and, by implication, for many other vector-borne diseases.
RP ROGERS, DJ (corresponding author), DEPT ZOOL,S PARKS RD,OXFORD OX1 3PS,ENGLAND.
NR 31
TC 141
Z9 152
U1 1
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 739
EP 741
DI 10.1038/351739a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100062
PM 2062367
DA 2026-03-10
ER

PT J
AU MORDECHAI, S
   MOORE, CF
AF MORDECHAI, S
   MOORE, CF
TI DOUBLE GIANT-RESONANCES IN ATOMIC-NUCLEI
SO NATURE
LA English
DT Article
ID double-charge-exchange; isobaric analog states; dipole resonance
AB Giant resonances are collective excitations of the nucleus in which a large fraction of the component nucleons are set into coherent modes of vibration. Double giant resonances, in which vibration is excited in a nucleus already undergoing a giant resonance, were predicted thirty years ago, but have only recently been observed experimentally. Their properties confirm broad aspects of nuclear structure theory, but show some anomalies that have yet to be explained.
C1 BEN GURION UNIV NEGEV,DEPT PHYS,IL-84105 BEER SHEVA,ISRAEL.
C3 Ben-Gurion University of the Negev
RP MORDECHAI, S (corresponding author), UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712, USA.
NR 20
TC 23
Z9 25
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 393
EP 397
DI 10.1038/352393a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600053
DA 2026-03-10
ER

PT J
AU PLUMMER, MR
   HESS, P
AF PLUMMER, MR
   HESS, P
TI REVERSIBLE UNCOUPLING OF INACTIVATION IN N-TYPE CALCIUM CHANNELS
SO NATURE
LA English
DT Article
ID single sodium-channels; chick sensory neurons; sympathetic neurons; ca-2+ channels; ca-channel; currents; release; sensitivity; modulation; membrane
AB N-TYPE calcium channels are thought to be expressed specifically in neuronal cells 1-3 and to have a dominant role in the control of neurotransmitter release from sympathetic neurons 4, 5.  But their unitary properties are poorly understood and the separation of neuronal Ca2+ current into components carried by N-type or L-type Ca2+ channels is controversial 6.  Here we show that individual N-type Ca2+ channels in sympathetic neurons can carry two kinetically distinct components of current, one that is rapidly transient and one that is long lasting.  The mechanism that gives rise to these two components is unexpected for Ca2+ channels:  a test depolarization elicits either a rapidly inactivating, single short burst with an average duration of 40 ms, or sustained, noninactivating channel activity lasting for over 1 s.  The switching between inactivating and noninactivating activity is a slow process, the occurrence of each type of unitary kinetic behaviour remaining statistically correlated over several seconds.  Variable coupling of inactivation in N-type Ca2+ channels could be an effective mechanism for the modulation of neuronal excitability and synaptic plasticity.
C1 HARVARD UNIV,SCH MED,PROGRAM NEUROSCI,DEPT CELLULAR & MOLEC PHYSIOL,BOSTON,MA 02115.
C3 Harvard University; Harvard Medical School
NR 27
TC 117
Z9 123
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 657
EP 659
DI 10.1038/351657a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200068
PM 1646965
DA 2026-03-10
ER

PT J
AU TABCHARANI, JA
   CHANG, XB
   RIORDAN, JR
   HANRAHAN, JW
AF TABCHARANI, JA
   CHANG, XB
   RIORDAN, JR
   HANRAHAN, JW
TI PHOSPHORYLATION-REGULATED CL- CHANNEL IN CHO CELLS STABLY EXPRESSING THE CYSTIC-FIBROSIS GENE
SO NATURE
LA English
DT Article
ID dependent protein-kinase; chloride channel; camp; toxin
AB A CYCLIC AMP-stimulated chloride conductance appears when the cystic fibrosis gene is expressed in non-epithelial cells by infection with recombinant viruses 1,2. Cyclic AMP-stimulated conductance in this system is mediated by the same ohmic, low-conductance Cl- channel as in human secretory epithelia 2-4, but control of this channel by phosphorylation has not been directly demonstrated. Here we report the appearance of the low-conductance Cl- channel in Chinese hamster ovary cells after stable transfection with the cystic fibrosis gene. The channel is regulated on-cell by membrane-permeant analogues of cAMP and off-cell by protein kinases A and C and by alkaline phosphatase. These results are further evidence that the cystic fibrosis transmembrane regulator is a Cl- channel which can be activated by specific phosphorylation events and inactivated by dephosphorylation; they reveal an unsuspected synergism between converging kinase regulatory pathways.
C1 MCGILL UNIV, DEPT PHYSIOL, 3655 DRUMMOND ST, MONTREAL H3G 1Y6, QUEBEC, CANADA.
   UNIV TORONTO, TORONTO M5S 1A1, ONTARIO, CANADA.
   HOSP SICK CHILDREN, RES INST, TORONTO M5G 1X8, ONTARIO, CANADA.
C3 McGill University; University of Toronto; University of Toronto; Hospital for Sick Children (SickKids)
NR 20
TC 536
Z9 584
U1 0
U2 9
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 628
EP 631
DI 10.1038/352628a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100058
PM 1714039
DA 2026-03-10
ER

PT J
AU TRINH, TQ
   SINDEN, RR
AF TRINH, TQ
   SINDEN, RR
TI PREFERENTIAL DNA SECONDARY STRUCTURE MUTAGENESIS IN THE LAGGING STRAND OF REPLICATION IN ESCHERICHIA-COLI
SO NATURE
LA English
DT Article
ID escherichia-coli; mutation; sequences; junction; repair; gene
AB WHEN present in single-stranded DNA, palindromic or quasipalindromic sequences have the potential to form complex secondary structures, including hairpins, which may facilitate interstrand misalignment of direct repeats and be responsible for diverse types of replication-based mutations, including deletions, additions, frameshifts and duplications 1-5.  In regions of palindromic symmetry, specific deletion events may involve the formation of a hairpin or other DNA secondary structures which can stabilize the misalignment of direct repeats 1,2.  One model suggests that these deletions occur during DNA replication by slippage of the template strand and misalignment with the progeny strand 6,7.  The concurrent DNA replication model, involving an asymmetric dimeric DNA polymerase III complex which replicates the leading and lagging strands 8, has significant implications for mutagenesis. The intermittent looping of the lagging strand template, and the fact that the lagging strand template may contain a region of single-stranded DNA the length of an Okazaki fragment, provides an opportunity for DNA secondary-structure formation and misalignment. Here we report our design of a palindromic fragment to create an 'asymmetric palindromic insert' in the chloramphenicol acetyltransferase gene of plasmid pBR325. The frequency with which the insert was deleted in Escherichia coli depends on the orientation of the gene in the plasmid. Our results suggest that replication-dependent deletion between direct repeats may occur preferentially in the lagging strand.
C1 UNIV CINCINNATI,COLL MED,DEPT MOLEC GENET BIOCHEM & MICROBIOL,231 BETHESDA AVE,CINCINNATI,OH 45267.
C3 University System of Ohio; University of Cincinnati
NR 17
TC 217
Z9 233
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 544
EP 547
DI 10.1038/352544a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600068
PM 1865910
DA 2026-03-10
ER

PT J
AU SERAFINI, T
   STENBECK, G
   BRECHT, A
   LOTTSPEICH, F
   ORCI, L
   ROTHMAN, JE
   WIELAND, FT
AF SERAFINI, T
   STENBECK, G
   BRECHT, A
   LOTTSPEICH, F
   ORCI, L
   ROTHMAN, JE
   WIELAND, FT
TI A COAT SUBUNIT OF GOLGI-DERIVED NON-CLATHRIN-COATED VESICLES WITH HOMOLOGY TO THE CLATHRIN-COATED VESICLE COAT PROTEIN BETA-ADAPTIN
SO NATURE
LA English
DT Article
ID cell-free system; luminal er proteins; brefeldin-a; endoplasmic-reticulum; plasma-membrane; intercompartmental transport; successive compartments; intracellular-transport; vesicular transport; secretory proteins
AB Four high-molecular-weight proteins form the main subunits of the coat of Golgi-derived (non-clathrin) coated vesicles.  One of these coat proteins, beta-COP, is identical to a Golgi-associated protein of relative mass 110,000 (110K) that shares homology with the adaptin proteins of clathrin-coated vesicles.  This connection, and the comparable molecular weights of the coat proteins of Golgi-derived and clathrin-coated vesicles, indicates that they may be structurally related.  The identification of beta-COP as the 110K protein explains the blocking of secretion by the drug brefeldin A.
C1 PRINCETON UNIV,DEPT MOLEC BIOL,PRINCETON,NJ 08544.
   UNIV HEIDELBERG,INST BIOCHEM 1,W-6900 HEIDELBERG,GERMANY.
   MAX PLANCK INST BIOCHEM,GENZENTRUM,W-8033 MARTINSRIED,GERMANY.
   UNIV GENEVA,DEPT MORPHOL,CH-1211 GENEVA 4,SWITZERLAND.
C3 Princeton University; Ruprecht Karls University Heidelberg; Max Planck Society; University of Geneva
RP SERAFINI, T (corresponding author), STANFORD UNIV,DEPT BIOCHEM,STANFORD,CA 94305, USA.
NR 51
TC 316
Z9 354
U1 1
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 214
EP 220
DI 10.1038/349215a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900046
PM 1898984
DA 2026-03-10
ER

PT J
AU REBANE, A
   FEINBERG, J
AF REBANE, A
   FEINBERG, J
TI TIME-RESOLVED HOLOGRAPHY
SO NATURE
LA English
DT Article
ID domain holography
AB IN a conventional hologram, a photographic film records the interference pattern of monochromatic light, scattered from the object to be imaged, with a reference beam of unscattered light.  Illumination of the developed film with a replica of the reference beam then creates a virtual image of the original object.  Here we show how a molecular resonance can be used to record an interference pattern between light signals that arrive at different times, and with this technique create a hologram with time resolution.  Using a timed reference pulse as a 'light shutter', we can record holographic images selectively, according to the time taken by light travelling from the object to the hologram.  We use this method to image an object behind a semi-opaque screen, and indicate how a similar method could be used to inspect objects embedded in a dense scattering medium.  Ultimately, this technique might be applied to the medical imaging of tumours.
C1 UNIV SO CALIF,DEPT PHYS,LOS ANGELES,CA 90089.
C3 University of Southern California
NR 8
TC 54
Z9 54
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 378
EP 380
DI 10.1038/351378a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600048
DA 2026-03-10
ER

PT J
AU ONDARCUHU, T
   VEYSSIE, M
AF ONDARCUHU, T
   VEYSSIE, M
TI RELAXATION MODES OF THE CONTACT LINE OF A LIQUID SPREADING ON A SURFACE
SO NATURE
LA English
DT Article
ID angle; dynamics
AB THE dynamics of spreading of liquids on solid surfaces are important in several practical and industrial processes, such as painting, lubrication and oil recovery in a porous medium. In all these situations, the motion of the 'contact line' at the edge of the advancing fluid is perturbed by the roughness and chemical contamination of the solid, which distort the line and give rise to poorly understood hysteresis effects. To elucidate these effects, one must begin by studying simplified processes, for example the time response to a perturbation of the line on an ideal surface. Here we describe a study of the dynamics of a contact line under controlled conditions of partial wetting, in which we determine the relationship between the characteristic decay time and the wavelength of a perturbation imposed on the line. When relaxation is controlled by the fluid viscosity, there is good agreement with theoretical predictions, but we observe deviations at long wavelengths which we ascribe to gravitational effects that weaken the contact line's elastic response.
RP ONDARCUHU, T (corresponding author), COLL FRANCE,PHYS MAT CONDENSEE LAB,11 PL MARCELIN BERTHELOT,F-75231 PARIS 05,FRANCE.
NR 11
TC 59
Z9 62
U1 1
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 418
EP 420
DI 10.1038/352418a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600059
DA 2026-03-10
ER

PT J
AU MISSIAEN, L
   TAYLOR, CW
   BERRIDGE, MJ
AF MISSIAEN, L
   TAYLOR, CW
   BERRIDGE, MJ
TI SPONTANEOUS CALCIUM RELEASE FROM INOSITOL TRISPHOSPHATE-SENSITIVE CALCIUM STORES
SO NATURE
LA English
DT Article
ID intracellular calcium; ca-2+ release; fura-2-loaded hepatocytes; oscillations; cells; 1,4,5-trisphosphate; mitochondria; phosphates; reticulum; binding
AB Inositol 1,4,5-trisphosphate (InsP3) functions as a second messenger to mobilize Ca2+ from intracellular reservoirs 1. The release mechanism displays all-or-none characteristics 2,3, that may account for other observations that the InsP3-induced mobilization of Ca2+ is quantal 4-6. Quantal release may depend on the sensitivity of the InsP3 receptor being regulated by the Ca2+ concentration in the lumen of the endoplasmic reticulum 7. We report here that the InsP3-sensitive store in hepatocytes discharges spontaneously when overloaded with Ca2+. The release, which is blocked by heparin, is preceded by an increasing sensitivity of the InsP3 receptor to endogenous InsP3, and is promoted by those sulphydryl reagents (oxidized glutathione and thimerosal) that induce Ca2+ oscillations in intact cells (ref. 8, and T. A. Rooney, D. C. Renard, E. J. Sass and A. P. Thomas, manuscript in preparation). This novel process could have a role in generating both Ca2+ oscillations and Ca2+ waves.
C1 UNIV CAMBRIDGE, DEPT PHARMACOL, CAMBRIDGE CB2 1QJ, ENGLAND.
C3 University of Cambridge
RP MISSIAEN, L (corresponding author), UNIV CAMBRIDGE, DEPT ZOOL, AFRC, MOLEC SIGNALLING LAB, DOWNING ST, CAMBRIDGE CB2 3EJ, ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 28
TC 341
Z9 353
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 241
EP 244
DI 10.1038/352241a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500066
PM 1857419
DA 2026-03-10
ER

PT J
AU STOVER, CK
   DELACRUZ, VF
   FUERST, TR
   BURLEIN, JE
   BENSON, LA
   BENNETT, LT
   BANSAL, GP
   YOUNG, JF
   LEE, MH
   HATFULL, GF
   SNAPPER, SB
   BARLETTA, RG
   JACOBS, WR
   BLOOM, BR
AF STOVER, CK
   DELACRUZ, VF
   FUERST, TR
   BURLEIN, JE
   BENSON, LA
   BENNETT, LT
   BANSAL, GP
   YOUNG, JF
   LEE, MH
   HATFULL, GF
   SNAPPER, SB
   BARLETTA, RG
   JACOBS, WR
   BLOOM, BR
TI NEW USE OF BCG FOR RECOMBINANT VACCINES
SO NATURE
LA English
DT Article
ID escherichia-coli; stress proteins; lymphocytes-t; invivo; mycobacteria; expression; sequence; tuberculosis; cloning; operon
AB BCG, a live attenuated tubercle bacillus, is the most widely used vaccine in the world and is also a useful vaccine vehicle for delivering protective antigens of multiple pathogens. Extrachromosomal and integrative expression vectors carrying the regulatory sequences for major BCG heat-shock proteins have been developed to allow expression of foreign antigens in BCG. These recombinant BCG strains can elicit long-lasting humoral and cellular immune responses to foreign antigens in mice.
C1 UNIV PITTSBURGH, DIV BIOL SCI, PITTSBURGH, PA 15260 USA.
   YESHIVA UNIV ALBERT EINSTEIN COLL MED, HOWARD HUGHES MED INST, BRONX, NY 10461 USA.
C3 Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; Yeshiva University; Montefiore Medical Center; Albert Einstein College of Medicine; Howard Hughes Medical Institute
RP STOVER, CK (corresponding author), MEDIMMUNE INC, GAITHERSBURG, MD 20878 USA.
NR 37
TC 1324
Z9 1702
U1 1
U2 64
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 456
EP 460
DI 10.1038/351456a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800046
PM 1904554
DA 2026-03-10
ER

PT J
AU HASEGAWA, A
   ZHAO, DP
   HORI, S
   YAMAMOTO, A
   HORIUCHI, S
AF HASEGAWA, A
   ZHAO, DP
   HORI, S
   YAMAMOTO, A
   HORIUCHI, S
TI DEEP-STRUCTURE OF THE NORTHEASTERN JAPAN ARC AND ITS RELATIONSHIP TO SEISMIC AND VOLCANIC ACTIVITY
SO NATURE
LA English
DT Article
ID velocity structure; structure beneath; earthquakes; mantle; zone; discontinuity; lithosphere; tomography; inversion; depths
AB Evidence for possible deep-seated magmatic activity beneath northeastern Japan can be obtained from seismic observations. Tomographic inversions of P-wave velocity data show low-velocity zones distributed in the crust and upper mantle beneath active volcanoes. In or around these zones, anomalously low-frequency micro-earthquakes, perhaps caused by magmatic activity, are found at depths of 25-40 km; distinct S-wave reflectors, corresponding to the upper surfaces of magma bodies, are found at depths of 10-18 km. Large crustal earthquakes also occur around the low-velocity zones. These observations reveal the distribution of magma reservoirs at depths and elucidate its relation with shallow seismicity beneath volcanic arcs.
RP HASEGAWA, A (corresponding author), TOHOKU UNIV,FAC SCI,OBSERVAT CTR PREDICT EARTHQUAKES & VOLCAN ERUPT,SENDAI,MIYAGI 980,JAPAN.
NR 30
TC 156
Z9 161
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 683
EP 689
DI 10.1038/352683a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400047
DA 2026-03-10
ER

PT J
AU PODSIADLOWSKI, P
AF PODSIADLOWSKI, P
TI IRRADIATION-DRIVEN MASS-TRANSFER IN LOW-MASS X-RAY BINARIES
SO NATURE
LA English
DT Article
ID magnetic braking; evolution; stars
AB IN a low-mass X-ray binary (LMXB), mass accreted onto a neutron star from a larger companion generates a flux of X-rays which irradiate the companion.  Previous studies of irradiated stars have been restricted to the effects on their outermost layers 1-5, or did not address conditions found in interacting binaries6.  Here I show that, under the radiative flux typical of a LMXB, the companion will expand towards a new state of thermal equilibrium, and that this expansion provides a new mechanism to drive mass transfer onto the neutron star.  The evolution of LMXBs can be drastically altered in this way.  In particular, this mechanism may introduce a new evolutionary phase during which the orbital period increases, leading to larger orbital periods during and at the end of mass transfer, and (if the companion is a subgiant) shortening the duration of the LMXB phase.  These modifications may help to resolve a number of observational puzzles concerning the numbers and properties of LMXBs and related objects.
RP PODSIADLOWSKI, P (corresponding author), UNIV CAMBRIDGE,INST ASTRON,MADINGLEY RD,CAMBRIDGE CB3 OHA,ENGLAND.
NR 17
TC 163
Z9 172
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 136
EP 138
DI 10.1038/350136a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500050
DA 2026-03-10
ER

PT J
AU HEMLEY, RJ
   HANFLAND, M
   MAO, HK
AF HEMLEY, RJ
   HANFLAND, M
   MAO, HK
TI HIGH-PRESSURE DIELECTRIC MEASUREMENTS OF SOLID HYDROGEN TO 170-GPA
SO NATURE
LA English
DT Article
ID phase-transition
AB AT high pressure (> 100 GPa), the valence-conduction band gap in solid hydrogen is predicted to decrease and eventually to close, transforming it from an insulator to a metal 1.  Recent experiments at pressures up to approximately 300 GPa suggest a gradual closing of the direct gap at very high pressures whereas closure of the indirect gap may occur at lower pressures, perhaps below 200 GPa (refs 2-6).  Measurements of the refractive index, n, and its frequency dependence (the dispersion dn/d-omega) as a function of pressure can provide information on the changes in electronic structure that occur under these conditions 7,8.  Here we report refractive-index measurements on solid hydrogen at visible frequencies at pressures up to 170 GPa.  Unlike earlier studies 9, we find no evidence for a divergence (dielectric instability) at 150 GPa, close to the low-temperature phase transition observed previously 6 and suggested as being associated with metallization 4,9.  Our results are consistent with closure of the indirect gap.  A fit of our data to a dielectric model indicates that the onset of visible absorption owing to direct interband transitions should occur above 200 GPa, consistent with previous direct observations 3.  Pressure-induced molecular dissociation may occur before closure of the direct gap.
RP HEMLEY, RJ (corresponding author), CARNEGIE INST WASHINGTON,GEOPHYS LAB,5251 BROAD BRANCH RD NW,WASHINGTON,DC 20015, USA.
NR 29
TC 52
Z9 54
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 488
EP 491
DI 10.1038/350488a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300046
DA 2026-03-10
ER

PT J
AU FOOTE, J
   MILSTEIN, C
AF FOOTE, J
   MILSTEIN, C
TI KINETIC MATURATION OF AN IMMUNE-RESPONSE
SO NATURE
LA English
DT Article
ID somatic mutation; antibody; anti-2-phenyloxazolone; 2-phenyloxazolone; sequences; oxazolone; mouse
AB IS the affinity maturation of antibodies under thermodynamic or kinetic control, or both? We compared the physical constants of hapten binding by antibodies from 2-phenyl-5-oxazolone-specific hybridomas from primary, secondary and tertiary responses. In addition to an increase in equilibrium constant, there was a shift in the antibody repertoire after the primary response towards an immunoglobulin family with an extremely high on-rate constant. This shift occurred in spite of the average or below-average affinity of this group of antibodies. This is consistent with B-lymphocyte proliferation being subject to a kinetic selection, with a premium on binding target antigens rapidly, in parallel with a thermodynamic selection based on binding tightly.
RP FOOTE, J (corresponding author), MRC, MOLEC BIOL LAB, HILLS RD, CAMBRIDGE CB2 2QH, ENGLAND.
NR 20
TC 269
Z9 309
U1 0
U2 16
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 530
EP 532
DI 10.1038/352530a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600063
PM 1907716
DA 2026-03-10
ER

PT J
AU REPRESA, J
   LEON, Y
   MINER, C
   GIRALDEZ, F
AF REPRESA, J
   LEON, Y
   MINER, C
   GIRALDEZ, F
TI THE INT-2 PROTOONCOGENE IS RESPONSIBLE FOR INDUCTION OF THE INNER-EAR
SO NATURE
LA English
DT Article
ID chick-embryo; sequence
AB THE int-2 proto-oncogene encodes several products related to the fibroblast growth factor (FGF) family 1,2.  FGFs have been associated with mesoderm induction in the amphibian embryo 2,3 and int-2 has a distinct pattern of expression throughout development in vertebrates 4,5.  But evidence for a function of int-2 in embryo-genesis has been lacking.  In the mouse embryo, int-2 transcripts have been detected in the rhombencephalon at a developmental stage where classical experiments showed that the induction of the inner ear occurs 6,7.  This raises the possibility that int-2 may constitute a signal for the induction of the otic vesicle, the primordium of the inner ear.  We provide direct evidence for this view by showing that (1) the formation of the otic vesicle is inhibited by antisense oligonucleotides targeted to the secreted form of int-2, and by antibodies against int-2 oncoproteins, and (2) basic FGF (bFGF) can mimic the inductive signal in the absence of the rhombencephalon.
C1 FAC MED VALLADOLID,DEPT BIOQUIM & BIOL MOLEC & FISIOL,E-47005 VALLADOLID,SPAIN.
   FAC MED VALLADOLID,DEPT CIENCIAS MORFOL,E-47005 VALLADOLID,SPAIN.
C3 Universidad de Valladolid; Universidad de Valladolid
NR 14
TC 166
Z9 172
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 561
EP 563
DI 10.1038/353561a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300068
PM 1922362
DA 2026-03-10
ER

PT J
AU HILL, DH
   BOYNTON, WV
   HAAG, RA
AF HILL, DH
   BOYNTON, WV
   HAAG, RA
TI A LUNAR METEORITE FOUND OUTSIDE THE ANTARCTIC
SO NATURE
LA English
DT Article
AB OUR knowledge of the Moon's surface composition has come from samples returned by the Apollo and Luna missions, and from eleven lunar meteorites, all of which were discovered in Antarctica 1,2. Here we report the discovery of a new lunar meteorite, Calcalong Creek, in a desert region of Australia which is analogous to Antarctica in its ability to preserve meteorites of different types 3. On the basis of a diagnostic Fe/Mn ratio of 73-78, and other element abundances, we conclude that Calcalong Creek is a lunar breccia, containing both highland and mare materials. Whereas the Apollo and Luna missions selectively sampled only 5% of the lunar crust, lunar meteorites should provide a random sample 4; nevertheless there has been some concern that the Antarctic meteorite population may be biased in some way 5. Calcalong Creek will add to our understanding of lunar petrology, and as the first non-Antarctic lunar meteorite, may also shed new light on the transfer of impact ejecta from the Moon to the Earth.
C1 UNIV ARIZONA,DEPT PLANETARY SCI,TUCSON,AZ 85721.
   ROBERT A HAAG METEORITES,TUCSON,AZ 85726.
C3 University of Arizona
RP HILL, DH (corresponding author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA.
NR 19
TC 35
Z9 38
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 614
EP 617
DI 10.1038/352614a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100053
DA 2026-03-10
ER

PT J
AU BARTOLOMEI, MS
   ZEMEL, S
   TILGHMAN, SM
AF BARTOLOMEI, MS
   ZEMEL, S
   TILGHMAN, SM
TI PARENTAL IMPRINTING OF THE MOUSE H19 GENE
SO NATURE
LA English
DT Article
ID expression; evolution; rna
AB THE mouse H19 gene encodes one of the most abundant RNAs in the developing mouse embryo 1.  It is expressed at the blastocyst stage of development, and accumulates to high levels in tissues of endodermal and mesodermal origin (H. Kim, unpublished result).  After birth the gene is repressed in all tissues except skeletal muscle.  It lacks a common open reading frame in the 2.5-kilobase RNA, but has considerable nucleotide sequence similarity between the genes of rodents and humans 2,3.  Expression of the gene in transgenic mice results in late prenatal lethality, suggesting that the dosage of its gene product is strictly controlled 4.  The H19 gene maps to the distal segment of mouse chromosome 7, in a region that is parentally imprinted 5, a process by which genes are differentially expressed on the maternal and paternal chromosomes.  We have now used an RNase protection assay that can distinguish between H19 alleles in four subspecies of Mus, to demonstrate that the H19 gene is parentally imprinted, with the active copy derived from the mother.  This assay will be of general use in assaying allele-specific gene expression.
C1 PRINCETON UNIV,DEPT MOLEC BIOL,PRINCETON,NJ 08544.
C3 Princeton University
RP BARTOLOMEI, MS (corresponding author), PRINCETON UNIV,HOWARD HUGHES MED INST,PRINCETON,NJ 08544, USA.
NR 23
TC 1040
Z9 1192
U1 2
U2 71
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 153
EP 155
DI 10.1038/351153a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500053
PM 1709450
DA 2026-03-10
ER

PT J
AU YOKOUCHI, Y
   SASAKI, H
   KUROIWA, A
AF YOKOUCHI, Y
   SASAKI, H
   KUROIWA, A
TI HOMEOBOX GENE-EXPRESSION CORRELATED WITH THE BIFURCATION PROCESS OF LIMB CARTILAGE DEVELOPMENT
SO NATURE
LA English
DT Article
ID retinoic acid; morphogenesis; cells
AB THE complex architecture of the limb cartilage pattern probably develops by the sequential segmentation and branching process of precartilaginous cell condensation under the control of positional signalling 1,2 provided by the zone of polarizing activity (anteroposterior) 3,4 and the apical ectodermal ridge (proximodistal) 5.  This signalling is monitored and interpreted in the mesenchymal cells and induces the position-specific response of subsets of genes.  Homeobox genes may be responsible for the interpretation of signalling 6-11.  A correlation between limb pattern and expression domains of the homeobox genes in the upstream region of Hox/Chox-4 has been proposed 10-12.  We have analysed the spatial expression pattern of the Chox-1 genes during development of chick limb buds.  In contrast to genes in Hox/Chox-4 expressed coordinately along the anteroposterior axis 10,11, homeobox genes in Chox-1 have unique and mutually exclusive expression domains along the proximodistal axis.  We report here that the expression domains of the Chox-1 genes are closely related to the segmental structure of cartilage along the proximodistal axis, whereas the expression domains of the Chox-4 genes are related to the cartilage branching pattern.
C1 TOHOKU UNIV,TB & CANC RES INST,DEPT CELL BIOL,4-1 SEIRYOMACHI,AOBA KU,SENDAI,MIYAGI 980,JAPAN.
   TOHOKU UNIV,FAC SCI,INST BIOL,AOBA KU,SENDAI,MIYAGI 980,JAPAN.
C3 Tohoku University; Tohoku University
NR 20
TC 297
Z9 311
U1 2
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 443
EP 445
DI 10.1038/353443a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600061
PM 1680221
DA 2026-03-10
ER

PT J
AU BUDRENE, EO
   BERG, HC
AF BUDRENE, EO
   BERG, HC
TI COMPLEX PATTERNS FORMED BY MOTILE CELLS OF ESCHERICHIA-COLI
SO NATURE
LA English
DT Article
ID chemotaxis; migration; movement
AB WHEN chemotactic strains of the bacterium Escherichia coli are inoculated on semi-solid agar containing mixtures of amino acids or sugars, the cells swarm outwards in a series of concentric rings:  they respond to spatial gradients of attractants generated by uptake and catabolism 1-3.  Cells also drift up gradients generated artificially, for example by diffusion from the tip of a capillary tube 4 or by mixing 5. Here we describe conditions under which cells aggregate in response to gradients of attractant which they excrete themselves.  When cells are grown in semi-solid agar on intermediates of the tricarboxylic acid cycle, they form symmetrical arrays of spots or stripes that arise sequentially.  When cells in a thin layer of liquid culture are exposed to these compounds, spots appear synchronously, more randomly arrayed. In either case, the patterns are stationary.  The attractant is a chemical sensed by the aspartate receptor.  Its excretion can be triggered by oxidative stress.  As oxygen is limiting at high cell densities, aggregation might serve as a mechanism for collective defence.
C1 ROWLAND INST SCI INC,CAMBRIDGE,MA 02142.
RP BUDRENE, EO (corresponding author), HARVARD UNIV,DEPT CELLULAR & DEV BIOL,16 DIVIN AVE,CAMBRIDGE,MA 02138, USA.
NR 22
TC 481
Z9 538
U1 3
U2 72
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 630
EP 633
DI 10.1038/349630a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000066
PM 2000137
DA 2026-03-10
ER

PT J
AU KONDRASHOV, AS
   CROW, JF
AF KONDRASHOV, AS
   CROW, JF
TI HAPLOIDY OR DIPLOIDY - WHICH IS BETTER
SO NATURE
LA English
DT Article
ID selection
AB ALTHOUGH the evolutionary advantages of sexual reproduction have been extensively discussed 1-3, much less attention has been paid to haploid and diploid phases of the sexual life cycle.  The relative lengths of these phases differ greatly in various taxa, including as extremes those with one or the other phase reduced to a single cell. Here we consider the efficiency of elimination of deleterious mutations as an evolutionary force and compare the mutation loads under haploid and diploid selection, L(n) and L2n.  With truncation-like selection, partial dominance, and heterozygous effect of a mutation less than about 1/4 its hemizygous effect, L2n < L(n); otherwise L2n > L(n).  The difference becomes important when the genomic deleterious mutation rate exceeds about 1 per genome.  This suggests that the mutation rate, degree of dominance and mode of selection can be important in life-cycle evolution.
C1 UNIV WISCONSIN,DEPT GENET,MADISON,WI 53706.
   ACAD SCI USSR,CTR RES COMP,PUSHCHINO 142292,USSR.
C3 University of Wisconsin System; University of Wisconsin Madison; Russian Academy of Sciences
NR 13
TC 154
Z9 176
U1 0
U2 32
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 314
EP 315
DI 10.1038/351314a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600059
PM 2034273
DA 2026-03-10
ER

PT J
AU KIM, SJ
   DROSSART, P
   CALDWELL, J
   MAILLARD, JP
   HERBST, T
   SHURE, M
AF KIM, SJ
   DROSSART, P
   CALDWELL, J
   MAILLARD, JP
   HERBST, T
   SHURE, M
TI IMAGES OF AURORAE ON JUPITER FROM H-3+ EMISSION AT 4 MU-M
SO NATURE
LA English
DT Article
ID fundamental-band
AB SINCE their discovery by Voyager 1, aurorae on Jupiter have been regularly observed over the past ten years, from space at ultraviolet wavelengths 2 and from the Earth in the thermal infrared band 3 (8-13-mu-m).  The ultraviolet emissions originate from H and H-2 in the highest part of the atmosphere, whereas the thermal infrared emissions originate from the stratosphere.  Here we present images of near-infrared H-3+ emission, recorded simultaneously with high-resolution spectra.  Having both imaging and spectral data provides us with a much improved opportunity to study the spatial and spectral characteristics of the H-3+ emission.  We find that northern and southern emissions show strong spatial variation at the wavelengths of H-3+ emission.  We suggest that the appearance of the jovian auroral regions at these wavelengths may be explained by a combination of localized H-3+ emission, reflection of sunlight by polar haze and stratospheric CH4 emission in the 3.3-3.6-mu-m range.
C1 INST ASTROPHYS,F-75014 PARIS,FRANCE.
   OBSERV PARIS,CNRS,UA 264,ASTROPHYS SECT,F-92195 MEUDON,FRANCE.
   YORK UNIV,DEPT PHYS,N YORK M3J 1P3,ONTARIO,CANADA.
   UNIV HAWAII MANOA,IRTF,INST ASTRON,HONOLULU,HI 96822.
C3 Sorbonne Universite; Universite PSL; Observatoire de Paris; Centre National de la Recherche Scientifique (CNRS); York University - Canada; University of Hawaii System; University of Hawaii Manoa
RP KIM, SJ (corresponding author), UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742, USA.
NR 12
TC 69
Z9 70
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 536
EP 539
DI 10.1038/353536a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300058
DA 2026-03-10
ER

PT J
AU WERY, JP
   SCHEVITZ, RW
   CLAWSON, DK
   BOBBITT, JL
   DOW, ER
   GAMBOA, G
   GOODSON, T
   HERMANN, RB
   KRAMER, RM
   MCCLURE, DB
   MIHELICH, ED
   PUTNAM, JE
   SHARP, JD
   STARK, DH
   TEATER, C
   WARRICK, MW
   JONES, ND
AF WERY, JP
   SCHEVITZ, RW
   CLAWSON, DK
   BOBBITT, JL
   DOW, ER
   GAMBOA, G
   GOODSON, T
   HERMANN, RB
   KRAMER, RM
   MCCLURE, DB
   MIHELICH, ED
   PUTNAM, JE
   SHARP, JD
   STARK, DH
   TEATER, C
   WARRICK, MW
   JONES, ND
TI STRUCTURE OF RECOMBINANT HUMAN RHEUMATOID ARTHRITIC SYNOVIAL-FLUID PHOSPHOLIPASE-A2 AT 2.2 A RESOLUTION
SO NATURE
LA English
DT Article
ID bovine pancreatic phospholipase-a2; transition-state analog; crystal-structure; extracellular phospholipase-a2; venom phospholipase-a2; nucleic-acids; force-field; purification; expression; refinement
AB PHOSPHOLIPASES A2 (PLA2s) may be grouped into distinct families of proteins that catalyse the hydrolysis of the 2-acyl bond of phospholipids and perform a variety of biological functions. The best characterized are the small (relative molecular mass approximately 14,000) calcium-dependent, secretory enzymes of diverse origin, such as pancreatic and venom PLA2s 1. The structures and functions of several PLA2s are known 2. Recently, high-resolution crystal structures of complexes of secretory PLA2s with phosphonate phospholipid analogues have provided information about the detailed stereochemistry of transition-state binding 3, confirming the proposed catalytic mechanism of esterolysis 4. By contrast, studies on mammalian nonpancreatic secretory PLA2S (s-PLA2S) have only recently begun; s-PLA2S are scarce in normal cells and tissues but large amounts are found in association with local and systemic inflammatory processes and tissue injury in animals and man 5-7. Such s-PLAs have been purified from rabbit and rat inflammatory exudate 8,9, from synovial fluid from patients with rheumatoid arthritis 10,11 and from human platelets 11. Cloning and sequencing shows that the primary structure of the human s-PLA2 11,12 has about 37% homology with that of bovine pancreatic PLA2 13 and 44% homology with that of Crotalus atrox PLA2 14. The human s-PLA2 is an unusually basic protein, yet contains most of the highly conserved amino-acid residues and sequences characteristic of the PLA2S sequenced so far 1,15. Here we report the refined, three-dimensional crystal structure at 2.2 angstrom resolution of recombinant human rheumatoid arthritic synovial fluid PLA2. This may aid the development of potent and specific inhibitors of this enzyme using structure-based design.
RP WERY, JP (corresponding author), ELI LILLY & CO,LILLY RES LAB,LILLY CORP CTR,INDIANAPOLIS,IN 46285, USA.
NR 29
TC 231
Z9 248
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 79
EP 82
DI 10.1038/352079a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800076
PM 2062381
DA 2026-03-10
ER

PT J
AU KAECH, S
   COVIC, L
   WYSS, A
   BALLMERHOFER, K
AF KAECH, S
   COVIC, L
   WYSS, A
   BALLMERHOFER, K
TI ASSOCIATION OF P60C-SRC WITH POLYOMA-VIRUS MIDDLE-T-ANTIGEN ABROGATING MITOSIS-SPECIFIC ACTIVATION
SO NATURE
LA English
DT Article
ID tyrosine phosphorylation; transforming protein; regulatory domain; pp60c-src; sites; kinase; gene; product; invivo
AB POLYOMA middle-T antigen is required for tumorigenesis in animals and for viral transformation of a variety of cells in culture (reviewed in ref. 1). Middle-T associates with and thereby activates p60c-src, a cellular tyrosine kinase homologous to the oncogene product of Rous sarcoma virus 2,3. Activation of p60c-src by middle-T is accompanied both by dephosphorylation of tyrosine 527, a site which negatively regulates src kinase activity (reviewed in refs 4-6) and by autophosphorylation on tyrosine 416 (refs 7-10). Phosphoprotein p60c-src is subject to cell cycle-specific regulation. It is most active during mitosis and repressed in interphase 11. Here we report that mitotic p60c-src is dephosphorylated at tyrosine 527. We also show that in cells expressing middle-T, src kinase activity is high both in mitosis and during interphase. An oncogenic mutant src protein, p60c-src(527F), where tyrosine 527 is substituted by phenylalanine, is also highly active in all phases of the cell cycle.
C1 FRIEDRICH MIESCHER INST, POB 2543, CH-4002 BASEL, SWITZERLAND.
C3 Friedrich Miescher Institute for Biomedical Research
NR 27
TC 55
Z9 56
U1 0
U2 1
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 431
EP 433
DI 10.1038/350431a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200053
PM 1707141
DA 2026-03-10
ER

PT J
AU HOGAN, CJ
AF HOGAN, CJ
TI FORMATION OF COSMIC STRUCTURE BY DOPPLER INSTABILITY
SO NATURE
LA English
DT Article
ID driven stellar winds; radiation; universe; model
AB A new mechanism is described which can create an instability in homogeneous gaseous matter at very low density. When an isotropic background radiation field has, near an electronic resonance (such as the hydrogen Lyman-alpha-line), a spectral feature for which photon occupation number increases with frequency, moving atoms increase their speed by taking energy from the photon distribution. In a cosmological setting, a sufficiently intense spectral feature can interact with neutral atomic gas, after recombination, to generate protogalactic perturbations of the scale and magnitude needed to explain large-scale cosmic structure.
C1 UNIV WASHINGTON, DEPT ASTRON, SEATTLE, WA 98195 USA.
   UNIV WASHINGTON, DEPT PHYS, SEATTLE, WA 98195 USA.
C3 University of Washington; University of Washington Seattle; University of Washington; University of Washington Seattle
RP HOGAN, CJ (corresponding author), KYOTO UNIV, YUKAWA INST THEORET PHYS, KYOTO 606, JAPAN.
NR 39
TC 8
Z9 8
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 469
EP 473
DI 10.1038/350469a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300040
DA 2026-03-10
ER

PT J
AU AMBROSE, WP
   MOERNER, WE
AF AMBROSE, WP
   MOERNER, WE
TI FLUORESCENCE SPECTROSCOPY AND SPECTRAL DIFFUSION OF SINGLE IMPURITY MOLECULES IN A CRYSTAL
SO NATURE
LA English
DT Article
ID para-terphenyl
AB MOTIVATED by the possibility of studying individual local environments in the solid state, there have been attempts to observe the optical absorption spectra of single impurity molecules trapped in crystals1,2. For example, time-dependent shifts in spectral features (spectral diffusion) are expected to result from motions of the molecules surrounding the impurity species. Recent advances in high-efficiency fluorescence excitation spectroscopy using ultra-thin sublimed crystals3 have now removed the earlier obstacle of low signal-to-noise ratios. Here we report the observation of jumps in the resonance frequency, on timescales of seconds to minutes, in the fluorescence excitation spectrum of single molecules of pentacene in crystals of p-terphenyl cooled to 1.5 K. These effects are seen, only for some impurities, which probably correspond to pentacene molecules in particularly strained local environments; most impurities show no time-dependent behaviour. We speculate on the possible causes of these spectral jumps, although further work will be required to draw definitive conclusions about the molecular motions involved.
RP AMBROSE, WP (corresponding author), IBM CORP, DIV RES, ALMADEN RES CTR, SAN JOSE, CA 95120 USA.
NR 18
TC 305
Z9 353
U1 0
U2 68
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 225
EP 227
DI 10.1038/349225a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900049
DA 2026-03-10
ER

PT J
AU LENARDO, MJ
AF LENARDO, MJ
TI INTERLEUKIN-2 PROGRAMS MOUSE ALPHA-BETA-LYMPHOCYTES-T FOR APOPTOSIS
SO NATURE
LA English
DT Article
ID staphylococcal enterotoxin-b; cell antigen receptor; stimulatory factor-i; monoclonal-antibody; proliferation; invivo; activation; clones; unresponsiveness; thymocytes
AB ANTIGEN receptor stimulation of mature alpha-beta-T lymphocytes can lead either to proliferation or death 1-4.  Programmed cell death, termed apoptosis, leads to the clonal deletion of both thymocytes and mature T cells that establishes tolerance 5-9.  How a mature T cell selects between proliferation and death is not understood. Here I show that interleukin-2 (IL-2) is a critical determinant of the choice between these two fates. Both CD4+ and CD8+ T cells previously exposed to IL-2 undergo apoptosis after antigen-receptor stimulation. Antibody blockade of IL-2 but not IL-4 reverses the marked reduction of lymph node V-beta-38+ T cells caused in mice by the bacterial superantigen Staphylococcus aureus enterotoxin B. IL-2 may thus participate in a feedback regulatory mechanism by predisposing mature T lymphocytes to apoptosis.
RP LENARDO, MJ (corresponding author), NIAID,IMMUNOL LAB,BLDG 10,RM 11N311,BETHESDA,MD 20892, USA.
NR 29
TC 988
Z9 1092
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 858
EP 861
DI 10.1038/353858a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200064
PM 1944559
DA 2026-03-10
ER

PT J
AU VARADI, G
   LORY, P
   SCHULTZ, D
   VARADI, M
   SCHWARTZ, A
AF VARADI, G
   LORY, P
   SCHULTZ, D
   VARADI, M
   SCHWARTZ, A
TI ACCELERATION OF ACTIVATION AND INACTIVATION BY THE BETA SUBUNIT OF THE SKELETAL-MUSCLE CALCIUM-CHANNEL
SO NATURE
LA English
DT Article
ID dihydropyridine receptor; functional expression; mammalian-cells; messenger-rna; cdna cloning; alpha-1-subunit; resolution; induction; existence; currents
AB THE L-type voltage-dependent calcium channel is an important link in excitation-contraction coupling of muscle cells 1 (reviewed in refs 2 and 3).  The channel has two functional characteristics:  calcium permeation and receptor sites for calcium antagonists.  In skeletal muscle the channel is a complex of five subunits, alpha-1, alpha-2, beta, gamma and delta (ref. 4).  Complementary DNAs to these subunits have been cloned and their amino-acid sequences deduced 5-8.  The skeletal muscle alpha-1 subunit cDNA expressed in L cells manifests as specific calcium-ion permeation, as well as sensitivity to the three classes of organic calcium-channel blockers 9,10.  We report here that coexpression of the alpha-1 subunit with other subunits results in significant changes in dihydropyridine binding and gating properties.  The available number of drug receptor sites increases 10-fold with an alpha-1-beta combination, whereas the affinity of the dihydropyridine binding site remains unchanged.  Also, the presence of the beta-subunit accelerates activation and inactivation kinetics of the calcium-channel current.
C1 UNIV CINCINNATI,DEPT PHARMACOL & CELL BIOPHYS,231 BETHESDA AVE,CINCINNATI,OH 45267.
C3 University System of Ohio; University of Cincinnati
NR 28
TC 272
Z9 293
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 159
EP 162
DI 10.1038/352159a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700058
PM 1712427
DA 2026-03-10
ER

PT J
AU WILSON, BS
   FINLEY, CC
   LAWSON, DT
   WOLFORD, RD
   EDDINGTON, DK
   RABINOWITZ, WM
AF WILSON, BS
   FINLEY, CC
   LAWSON, DT
   WOLFORD, RD
   EDDINGTON, DK
   RABINOWITZ, WM
TI BETTER SPEECH RECOGNITION WITH COCHLEAR IMPLANTS
SO NATURE
LA English
DT Article
ID processing strategy; previous experience; confounding factor; deaf subjects; performance; psychophysics; reception; schemes; cues; aid
AB HIGH levels of speech recognition have been achieved with a new sound processing strategy for multielectrode cochlear implants. A cochlear implant system consists of one or more implanted electrodes for direct electrical activation of the auditory nerve, an external speech processor that transforms a microphone input into stimuli for each electrode, and a transcutaneous (rf-link) or percutaneous (direct) connection between the processor and the electrodes. We report here the comparison of the new strategy and a standard clinical processor. The standard compressed analogue (CA) processor 1,2 presented analogue waveforms simultaneously to all electrodes, whereas the new continuous interleaved sampling (CIS) strategy presented brief pulses to each electrode in a nonoverlapping sequence. Seven experienced implant users, selected for their excellent performance with the CA processor, participated as subjects. The new strategy produced large improvements in the scores of speech reception tests for all subjects. These results have important implications for the treatment of deafness and for minimal representations of speech at the auditory periphery.
C1 DUKE UNIV, MED CTR, DIV OTOLARYNGOL, DURHAM, NC 27710 USA.
   DUKE UNIV, MED CTR, CTR SPEECH & HEARING DISORDERS, DURHAM, NC 27710 USA.
   MIT, ELECTR RES LAB, CAMBRIDGE, MA 02139 USA.
   MASSACHUSETTS EYE & EAR HOSP, COCHLEAR IMPLANT RES LAB, BOSTON, MA 02114 USA.
   HARVARD UNIV, SCH MED, DEPT OTOL & LARYNGOL, BOSTON, MA 02115 USA.
C3 Duke University; Duke University; Massachusetts Institute of Technology (MIT); Harvard University; Harvard Medical School
RP WILSON, BS (corresponding author), RES TRIANGLE INST, NEUROSCI PROGRAM, RES TRIANGLE PK, NC 27709 USA.
NR 32
TC 920
Z9 1125
U1 2
U2 151
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 236
EP 238
DI 10.1038/352236a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500064
PM 1857418
DA 2026-03-10
ER

PT J
AU HSU, IC
   METCALF, RA
   SUN, T
   WELSH, JA
   WANG, NJ
   HARRIS, CC
AF HSU, IC
   METCALF, RA
   SUN, T
   WELSH, JA
   WANG, NJ
   HARRIS, CC
TI MUTATIONAL HOTSPOT IN THE P53 GENE IN HUMAN HEPATOCELLULAR CARCINOMAS
SO NATURE
LA English
DT Article
ID dna; exposure
AB HUMAN hepatocellular carcinomas (HCC) from patients in Qidong, an area of high incidence in China, in which both hepatitis B virus and aflatoxin B1 are risk factors 1, were analysed for mutations in p53, a putative tumour-suppressor gene.  Eight of the 16 HCC had a point mutation at the third base position of codon 249.  The G --> T transversion in seven HCC DNA samples and the G --> C transversion in the other HCC are consistent with mutations caused by aflatoxin B1 in mutagenesis experiments 2,3.  No mutations were found in exons 5, 6, 8 or the remainder of exon 7.  These results contrast with p53 mutations previously reported in carcinomas and sarcomas of human lung, colon, oesophagus and breast; these are primarily scattered over four of the five evolutionarily conserved domains, which include codon 249 (refs 4-9).  We suggest that the mutant p53 protein may be responsible for a selective clonal expansion of hepatocytes during carcinogenesis.
C1 NCI,DIV CANC ETIOL,HUMAN CARCINOGENESIS LAB,BETHESDA,MD 20892.
   UNIV MARYLAND,SCH MED,DEPT PATHOL,BALTIMORE,MD 21201.
   CHINESE ACAD MED SCI,INST CANC,BEIJING,PEOPLES R CHINA.
   QIDONG LIVER CANC INST,JIANGSU,PEOPLES R CHINA.
C3 National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); University System of Maryland; University of Maryland Baltimore; Chinese Academy of Medical Sciences - Peking Union Medical College
NR 25
TC 1489
Z9 1618
U1 0
U2 72
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 427
EP 428
DI 10.1038/350427a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200051
PM 1849234
DA 2026-03-10
ER

PT J
AU SCHNELL, RC
   LIU, SC
   OLTMANS, SJ
   STONE, RS
   HOFMANN, DJ
   DUTTON, EG
   DESHLER, T
   STURGES, WT
   HARDER, JW
   SEWELL, SD
   TRAINER, M
   HARRIS, JM
AF SCHNELL, RC
   LIU, SC
   OLTMANS, SJ
   STONE, RS
   HOFMANN, DJ
   DUTTON, EG
   DESHLER, T
   STURGES, WT
   HARDER, JW
   SEWELL, SD
   TRAINER, M
   HARRIS, JM
TI DECREASE OF SUMMER TROPOSPHERIC OZONE CONCENTRATIONS IN ANTARCTICA
SO NATURE
LA English
DT Article
ID profile measurements; mcmurdo station; destruction; pacific; hole
AB AS an oxidant and a precursor for other highly reactive oxidants, ozone plays an important role in tropospheric photochemistry. In the upper troposphere, ozone absorbs infrared radiation and is thus an effective greenhouse gas 1.  Here we show that surface ozone concentrations at the South Pole in the austral summer decreased by 17% over the period 1976-90. Over the same period, solar irradiance at the South Pole in January and February decreased by 7% as a result of a 25% increase in cloudiness. We suggest that the trend in the summer ozone concentrations is caused by enhanced photochemical destruction of ozone in the lower troposphere caused by the increased penetration of ultraviolet radiation associated with stratospheric ozone depletion, coupled with enhanced transport of ozone-poor marine air from lower latitudes to the South Pole.
C1 NOAA,AERON LAB,BOULDER,CO 80303.
   NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303.
   UNIV WYOMING,DEPT PHYS & ASTRON,LARAMIE,WY 82071.
   UNIV COLORADO,DEPT GEOG,BOULDER,CO 80303.
C3 National Oceanic Atmospheric Admin (NOAA) - USA; National Oceanic Atmospheric Admin (NOAA) - USA; University of Wyoming; University of Colorado System; University of Colorado Boulder
RP SCHNELL, RC (corresponding author), UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309, USA.
NR 36
TC 57
Z9 63
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 726
EP 729
DI 10.1038/351726a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100057
DA 2026-03-10
ER

PT J
AU DRISCOLL, PC
   CYSTER, JG
   CAMPBELL, ID
   WILLIAMS, AF
AF DRISCOLL, PC
   CYSTER, JG
   CAMPBELL, ID
   WILLIAMS, AF
TI STRUCTURE OF DOMAIN-1 OF RAT LYMPHOCYTE-T CD2 ANTIGEN
SO NATURE
LA English
DT Article
ID immunoglobulin superfamily; 3-dimensional structure; crystal-structure; protein; fragment; spectroscopy; activation; resolution; receptors; sequences
AB THE CD2 antigen is largely restricted to cells of the T-lymphocyte lineage and has been established as an important adhesion molecule in interactions between human T lymphocytes and accessory cells 1. In the adhesion reaction, CD2 on T cells binds to LFA-3 on other cells, with binding through domain 1 of CD2 (ref. 2). CD2 can also be a target for the delivery of mitogenic signals to T lymphocytes cultured with combinations of anti-CD2 antibodies 3,4. Two predictions that are contradictory have been made for the structure of CD2 domain 1. One suggests an immunoglobulin (Ig) fold, on the basis of sequence patterns conserved in the Ig-superfamily (IgSF) 5, whilst the other proposes a pattern of alternating alpha-helices and beta-strands, on the basis of secondary structure predictions 6. Thus CD2 domain 1 is an important test case for the validity of IgSF assignments based on sequence patterns. We report here the expression of domain 1 of rat CD2 in an Escherichia coli expression system and have determined a low-resolution solution structure by NMR spectroscopy.
C1 UNIV OXFORD, SIR WILLIAM DUNN SCH PATHOL, MRC, CELLULAR IMMUNOL RES UNIT, OXFORD OX1 3RE, ENGLAND.
C3 University of Oxford
RP DRISCOLL, PC (corresponding author), UNIV OXFORD, DEPT BIOCHEM, OXFORD OX1 3QU, ENGLAND.
NR 29
TC 150
Z9 167
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 762
EP 765
DI 10.1038/353762a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600071
PM 1682812
DA 2026-03-10
ER

PT J
AU FLEMING, RM
   ROSSEINSKY, MJ
   RAMIREZ, AP
   MURPHY, DW
   TULLY, JC
   HADDON, RC
   SIEGRIST, T
   TYCKO, R
   GLARUM, SH
   MARSH, P
   DABBAGH, G
   ZAHURAK, SM
   MAKHIJA, AV
   HAMPTON, C
AF FLEMING, RM
   ROSSEINSKY, MJ
   RAMIREZ, AP
   MURPHY, DW
   TULLY, JC
   HADDON, RC
   SIEGRIST, T
   TYCKO, R
   GLARUM, SH
   MARSH, P
   DABBAGH, G
   ZAHURAK, SM
   MAKHIJA, AV
   HAMPTON, C
TI PREPARATION AND STRUCTURE OF THE ALKALI-METAL FULLERIDE A4C60
SO NATURE
LA English
DT Article
AB SUPERCONDUCTING K3C60 (ref. 1) has been shown 2 to have an intercalated face-centred cubic (f.c.c.) structure, and other A3C60 compounds (where A is K, Rb or mixtures of K, Rb and/or Cs) form an isostructural series with superconducting transition temperatures up to 31.3 K (ref. 3). Recently we reported 4 C-13 NMR studies of K(x)C60 for x < 3, and concluded that the system contained two phases (x = 0 and x = 3) for 0 < x < 3. Here we report an investigation of A(x)C60 in the range 3 < x < 6 and find evidence for an additional phase at x = 4. In contrast to f.c.c. A3C60 (refs 2, 3) and body-centred cubic A6C60 (ref. 5), A4C60 (where A is K, Rb, Cs) has a body-centred tetragonal structure. We show that all of the experimentally observed phases of A(x)C60 can be predicted solely on the basis of electrostatic considerations. We have found no evidence for superconductivity in A4C60.
RP FLEMING, RM (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 7
TC 303
Z9 311
U1 1
U2 57
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 701
EP 703
DI 10.1038/352701a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400052
DA 2026-03-10
ER

PT J
AU YAMASHIRO, S
   YAMAKITA, Y
   HOSOYA, H
   MATSUMURA, F
AF YAMASHIRO, S
   YAMAKITA, Y
   HOSOYA, H
   MATSUMURA, F
TI PHOSPHORYLATION OF NONMUSCLE CALDESMON BY P34CDC2 KINASE DURING MITOSIS
SO NATURE
LA English
DT Article
ID maturation-promoting factor; control gene cdc2+; cell-cycle; smooth-muscle; protein-kinase; m-phase; activation; component; regulator; homologs
AB One of the profound changes in cellular morphology which occurs during mitosis is a massive alteration in the organization of the microfilament cytoskeleton 1,2.  This change, together with other mitotic events including nuclear membrane breakdown, chromosome condensation and formation of mitotic spindles, is induced by a molecular complex called maturation promoting factor 3-5.  This consists of at least two subunits, a polypeptide for relative molecular mass 45,000-62,000 (M(r) 45-62K) known as cyclin, and a 34K catalytic subunit which as series/threonine kinase activity and is known as cdc2 kinase 6-9. Non-muscle caldesmon, an 83K actin- and calmodulin-binding protein, is dissociated from microfilaments during mitosis, apparently as a consequence of mitosis-specific phosphorylation 10.  We now report that cdc2 kinase phosphorylates caldesmon in vitro principally at the same sites as those phosphorylated in vivo during mitosis, and that phosphorylation reduces the binding affinity of caldesmon for both actin and calmodulin. Because caldesmon inhibits actomyosin ATPase, our results suggest that cdc2 kinase directly causes microfilament reorganization during mitosis.
C1 TOKYO METROPOLITAN INST MED SCI,TOKYO 113,JAPAN.
C3 Tokyo Metropolitan Institute of Medical Science
RP YAMASHIRO, S (corresponding author), RUTGERS STATE UNIV,DEPT MOLEC BIOL & BIOCHEM,NELSON HALL,BUSCH CAMPUS,PISCATAWAY,NJ 08855, USA.
NR 20
TC 166
Z9 177
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 169
EP 172
DI 10.1038/349169a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800063
PM 1986309
DA 2026-03-10
ER

PT J
AU BARCONS, X
   FABIAN, AC
   REES, MJ
AF BARCONS, X
   FABIAN, AC
   REES, MJ
TI THE PHYSICAL STATE OF THE INTERGALACTIC MEDIUM
SO NATURE
LA English
DT Article
ID universe; nucleosynthesis
AB BECAUSE the process of galaxy formation is most unlikely to be perfectly efficient, there is a strong possibility that some baryonic gas remains outside collapsed structures such as galaxies and clusters of galaxies. What fraction of the baryonic content of the Universe resides in this intergalactic medium (IGM) and what physical state it is in are open questions. Here we use observational limits on the density of neutral hydrogen in the IGM, on the lack of deviations from a black-body spectrum of the cosmic microwave background (MBR), and on the extragalactic component of the soft X-ray background (XRB) to constrain the state of the IGM. From the lack of MBR fluctuations, any energetic IGM (containing as much energy as the binding energy in galaxies) is inferred to be smoothly distributed on scales greater than galactic. This rules out hot IGM models for the origin of the hard X-ray background, as well as the hypothesis that cosmic explosions may have given rise to cosmological structure on scales larger than galaxies.
C1 UNIV CAMBRIDGE, INST ASTRON, CAMBRIDGE CB3 0HA, ENGLAND.
C3 University of Cambridge
RP BARCONS, X (corresponding author), UNIV CANTABRIA, DEPT FIS MODERNA, E-39005 SANTANDER, SPAIN.
NR 21
TC 30
Z9 30
U1 0
U2 1
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 685
EP 687
DI 10.1038/350685a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000052
DA 2026-03-10
ER

PT J
AU VAGHJIANI, GL
   RAVISHANKARA, AR
AF VAGHJIANI, GL
   RAVISHANKARA, AR
TI NEW MEASUREMENT OF THE RATE COEFFICIENT FOR THE REACTION OF OH WITH METHANE
SO NATURE
LA English
DT Article
ID flash-photolysis; climate change; kinetics; ch4; chemistry
AB METHANE is an important greenhouse gas, whose concentration in the troposphere is steadily increasing.  To estimate the flux of methane into the atmosphere and its atmospheric lifetime, its rate of removal needs to be accurately determined.  The main loss process for atmospheric methane is the reaction with the hydroxyl radical OH.  We have measured the rate coefficient for this reaction in carefully controlled experiments and found it to be smaller than currently accepted values.  Our results indicate a longer CH4 lifetime (by approximately 25%) and a correspondingly smaller flux (by approximately 100 Tg CH4 yr-1) than previously calculated.
C1 NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303.
   UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309.
   UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309.
C3 National Oceanic Atmospheric Admin (NOAA) - USA; University of Colorado System; University of Colorado Boulder; National Oceanic Atmospheric Admin (NOAA) - USA; University of Colorado System; University of Colorado Boulder
NR 18
TC 193
Z9 208
U1 1
U2 62
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 406
EP 409
DI 10.1038/350406a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200043
DA 2026-03-10
ER

PT J
AU CEULEMANS, A
   FOWLER, PW
AF CEULEMANS, A
   FOWLER, PW
TI EXTENSION OF EULER THEOREM TO SYMMETRY PROPERTIES OF POLYHEDRA
SO NATURE
LA English
DT Article
ID clusters; numbers; c-60
AB POLYHEDRAL cages and clusters are widespread in chemistry. Examples of fully triangulated polyhedra (deltahedra) are the skeletons of closo-boranes B(n)H(n)2-, many heteroboranes and transition-metal carbonyls 1.  Three-connected cages occur for carbon 2,3 and in zeolites 1.  The numbers v, f and e of vertices, faces and edges of a convex polyhedron are related by Euler's theorem 4,5 v + f = e + 2. Here we show that within the point group of the polyhedron the symmetries spanned by the sets of vertices, faces and edges are also related. We prove a general theorem relating these symmetries for convex polyhedra, and give further relations specific to deltahedra and 3-connected polyhedra. The latter extensions of Euler's theorem to point-group characters allow us to generate complete sets of internal vibrational coordinates from bond stretches for deltahedra, and to classify, from symmetry properties alone, the bonding or antibonding nature of molecular orbitals of 3-connected cages.
C1 UNIV EXETER,DEPT CHEM,EXETER EX4 4RJ,DEVON,ENGLAND.
C3 University of Exeter
RP CEULEMANS, A (corresponding author), UNIV LOUVAIN,DEPT CHEM,CELESTIJNENLAAN 200F,B-3001 LOUVAIN,BELGIUM.
NR 13
TC 47
Z9 51
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 52
EP 54
DI 10.1038/353052a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500053
DA 2026-03-10
ER

PT J
AU HARZ, H
   HEGEMANN, P
AF HARZ, H
   HEGEMANN, P
TI RHODOPSIN-REGULATED CALCIUM CURRENTS IN CHLAMYDOMONAS
SO NATURE
LA English
DT Article
ID alga haematococcus-pluvialis; reinhardtii; phototaxis; membrane
AB THE unicellular alga Chlamydomonas reinhardtii responds to weak flashes of light by changing its swimming direction and to brighter flashes with transient backward swimming (the stop or phobic response) 1,2. In continuous light the cells swim towards or away from the light source (phototaxis) 3,4. This behaviour is controlled by a visual system with a rhodopsin as the functional photoreceptor 5,6. Physiological experiments under different ionic conditions have suggested that ionic processes are involved in the signal transduction from the photoreceptor to the flagella 1,2,4. Here we show by ion current measurements that there are two distinct light-regulated inward currents which are localized in the eyespot and in the flagellar region of the cell. From the kinetics and the rhodopsin action spectrum of these photocurrents we conclude that they are part of the rhodopsin-regulated signal transduction chain controlling the cellular behaviour in light. Both photocurrents are Ca2+-dependent and are suppressed by the Ca2+-channel inhibitors verapamil and pimozide, suggesting that the photoreceptor current and probably the flagellar current are both carried by Ca2+.
RP HARZ, H (corresponding author), MAX PLANCK INST BIOCHEM, KLOPFERSPITZ, W-8033 MARTINSRIED, GERMANY.
NR 23
TC 204
Z9 235
U1 0
U2 51
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 489
EP 491
DI 10.1038/351489a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800058
DA 2026-03-10
ER

PT J
AU MAURETTE, M
   OLINGER, C
   MICHELLEVY, MC
   KURAT, G
   POURCHET, M
   BRANDSTATTER, F
   BOUROTDENISE, M
AF MAURETTE, M
   OLINGER, C
   MICHELLEVY, MC
   KURAT, G
   POURCHET, M
   BRANDSTATTER, F
   BOUROTDENISE, M
TI A COLLECTION OF DIVERSE MICROMETEORITES RECOVERED FROM 100 TONNES OF ANTARCTIC BLUE ICE
SO NATURE
LA English
DT Article
ID unequilibrated ordinary chondrites; deep-sea sediments; interplanetary dust; noble-gases; meteorites
AB STUDIES of meteorites and interplanetary dust particles (IDPs) have provided constraints on the formation and evolution of the Solar System 1, and have identified pre-solar interstellar grains 2-4.  Here we describe a new type of meteoritic material, intermediate in size between meteorites and IDPs.  Melting and filtering of approximately 100 tonnes of blue ice near Cap Prudhomme, Antarctica, yielded greater-than-or-equal-to 7,500 irregular, friable particles and approximately 1,500 melted spherules, approximately 100-mu-m in size, both showing a 'chondritic' composition suggestive of an extraterrestrial origin 5,6.  For the present work, we analysed the composition and texture of 51 irregular particles and 25 spherules.  The irregular particles appear to be unmelted, and have similarities with the fine-grained matrix of primitive carbonaceous chondrites, but are extremely diverse in composition.  Isotopic analysis of trapped neon confirms an extraterrestrial origin for 16 of 47 irregular particles and 2 of 19 spherules studied, and strongly suggests that they were exposed in space as micrometeoroids.  These large Antarctic micrometeorites constitute a new family-or at least a new population-of Solar System objects, in a mass range corresponding to the bulk of extraterrestrial material accreted by the Earth today.
C1 WASHINGTON UNIV,MCDONNELL CTR SPACE SCI,ST LOUIS,MO 63130.
   WASHINGTON UNIV,DEPT PHYS,ST LOUIS,MO 63130.
   UNIV PARIS 06,MINERAL CRISTALLOG LAB,F-75252 PARIS,FRANCE.
   NAT HIST MUSEUM,A-1014 VIENNA,AUSTRIA.
   LAB GLACIOL,F-38402 ST MARTIN DHERES,FRANCE.
   MUSEUM NATL HIST NAT,MINERAL LAB,F-75231 PARIS 05,FRANCE.
C3 Washington University (WUSTL); Washington University (WUSTL); Sorbonne Universite; Museum National d'Histoire Naturelle (MNHN)
RP MAURETTE, M (corresponding author), CNRS,INST NATL PHYS NUCL & PHYS PARTICULES,CSNSM,BATIMENT 108,F-91405 ORSAY,FRANCE.
NR 29
TC 215
Z9 227
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 44
EP 47
DI 10.1038/351044a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300052
DA 2026-03-10
ER

PT J
AU SIXMA, TK
   PRONK, SE
   KALK, KH
   WARTNA, ES
   VANZANTEN, BAM
   WITHOLT, B
   HOL, WGJ
AF SIXMA, TK
   PRONK, SE
   KALK, KH
   WARTNA, ES
   VANZANTEN, BAM
   WITHOLT, B
   HOL, WGJ
TI CRYSTAL-STRUCTURE OF A CHOLERA TOXIN-RELATED HEAT-LABILE ENTEROTOXIN FROM ESCHERICHIA-COLI
SO NATURE
LA English
DT Article
ID aeruginosa exotoxin-a; adp-ribosyltransferase activity; amino-acid-sequence; x-ray-diffraction; escherichia-coli; pseudomonas-aeruginosa; nucleotide-sequence; b-subunit; diphtheria-toxin; 3-dimensional structure
AB Examination of the structure of Escherichia coli heat-labile enterotoxin in the AB5 complex at a resolution of 2.3 angstrom reveals that the doughnut-shaped B pentamer binds the enzymatic A subunit using a hairpin of the A2 fragment, through a highly charged central pore. Putative ganglioside G(M1-) binding sites on the B subunits are more than 20 angstrom removed from the membrane-crossing A1 subunit. This ADP-ribosylating (A1) fragment of the toxin has structural homology with the catalytic region of exotoxin A and hence also to diphtheria toxin.
C1 STATE UNIV GRONINGEN, DEPT CHEM, BIOCHEM LAB, 9747 AG GRONINGEN, NETHERLANDS.
C3 University of Groningen
RP SIXMA, TK (corresponding author), STATE UNIV GRONINGEN, BIOSON RES INST, NIJENBORGH 16, 9747 AG GRONINGEN, NETHERLANDS.
NR 65
TC 499
Z9 548
U1 1
U2 22
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 371
EP 377
DI 10.1038/351371a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600047
PM 2034287
DA 2026-03-10
ER

PT J
AU SASAKI, K
   YAMANO, Y
   BARDHAN, S
   IWAI, N
   MURRAY, JJ
   HASEGAWA, M
   MATSUDA, Y
   INAGAMI, T
AF SASAKI, K
   YAMANO, Y
   BARDHAN, S
   IWAI, N
   MURRAY, JJ
   HASEGAWA, M
   MATSUDA, Y
   INAGAMI, T
TI CLONING AND EXPRESSION OF A COMPLEMENTARY-DNA ENCODING A BOVINE ADRENAL ANGIOTENSIN-II TYPE-1 RECEPTOR
SO NATURE
LA English
DT Article
ID binding-sites; solubilization; membranes; sequence; subtypes; cortex
AB ANGIOTENSIN II elicits different responses which affect cardiovascular, neuronal and electrolyte transport regulation 1. To understand the mechanisms responsible for its various actions, the receptor for angiotensin II has long been sought, but numerous attempts to purify the receptor have been unsuccessful owing to its instability and low concentration 2-6. We report here the expression cloning of a complementary DNA encoding a bovine angiotensin II receptor to overcome these difficulties. The receptor cDNA encodes a protein of 359 amino-acid residues with a transmembrane topology similar to that of other G protein-coupled receptors. COS-7 cells transfected with cDNA expressed specific and high-affinity binding sites for angiotensin II, angiotensin II antagonist and a non-peptide specific antagonist for type-1 receptor. Dithiothreitol inhibited ligand binding. The concentration of intracellular Ca2+ and of inositol-1,4,5-trisphospate increased in the transfected COS-7 cells in response to angiotensin II or angiotensin III, indicating that this receptor is the type-1 receptor for angiotensin II. Northern blot analysis revealed that the messenger RNA for this receptor is expressed in bovine adrenal medulla, cortex and kidney.
C1 VANDERBILT UNIV, DEPT BIOCHEM, NASHVILLE, TN 37232 USA.
   VANDERBILT UNIV, DEPT MED, NASHVILLE, TN 37232 USA.
   KYOWA HAKKO KOGYO CO LTD, TOKYO RES LABS, TOKYO 194, JAPAN.
C3 Vanderbilt University; Vanderbilt University; Kyowa Kirin Ltd
NR 26
TC 823
Z9 861
U1 0
U2 29
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 230
EP 233
DI 10.1038/351230a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000056
PM 2041569
DA 2026-03-10
ER

PT J
AU WU, L
   SCOLLAY, R
   EGERTON, M
   PEARSE, M
   SPANGRUDE, GJ
   SHORTMAN, K
AF WU, L
   SCOLLAY, R
   EGERTON, M
   PEARSE, M
   SPANGRUDE, GJ
   SHORTMAN, K
TI CD4 EXPRESSED ON EARLIEST T-LINEAGE PRECURSOR CELLS IN THE ADULT MURINE THYMUS
SO NATURE
LA English
DT Article
ID homing progenitor cells; interleukin-2 receptor; monoclonal-antibody; pgp-1 glycoprotein; mouse thymus; stem-cells; thymocytes; surface; antigen; subpopulations
AB A CONTINUOUS but low input of stem cells or 'prothymocytes' is necessary to maintain T-cell development in the adult thymus1, but the colonizing cell has not been characterized.  Precursors of T cells have been found in the minor CD4-8- population2 of thymocytes, but even the earliest cells of this population already have partially rearranged T-cell antigen receptor (TCR) genes3.  We now demonstrate that the thymus contains a minute population of lymphoid cells similar in some but not all respects to bone marrow-derived haemopoietic stem cells.  This population has TCR genes in a germline state.  It gives a slow but extensive reconstitution of both alpha-beta and gamma-delta-lineages on transfer into an irradiated thymus, with kinetics indicating that it includes the earliest intrathymic precursor cells so far isolated. Surprisingly, these cells express low surface levels of the mature T-cell marker CD4.
C1 ROYAL MELBOURNE HOSP,WALTER & ELIZA HALL INST MED RES,PARKVILLE,VIC 3050,AUSTRALIA.
C3 Walter & Eliza Hall Institute; Melbourne Health; Royal Melbourne Hospital
NR 30
TC 340
Z9 363
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 71
EP 74
DI 10.1038/349071a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100054
PM 1702186
DA 2026-03-10
ER

PT J
AU ELLIOTT, TR
   HAWKESWORTH, CJ
   GRONVOLD, K
AF ELLIOTT, TR
   HAWKESWORTH, CJ
   GRONVOLD, K
TI DYNAMIC MELTING OF THE ICELAND PLUME
SO NATURE
LA English
DT Article
ID ocean ridge basalts; reykjanes peninsula basalts; mid-atlantic ridge; mantle evolution; beneath iceland; isotope ratios; famous area; magma; lead; strontium
AB Icelandic high-magnesia basalts show striking correlations between major element abundances and incompatible element and radiogenic isotope ratios.  The most MgO-rich lavas have the most depleted incompatible element ratios and among the least radiogenic lead isotopes recorded in Atlantic mid-ocean-ridge basalts, highlighting a decoupling of the major and trace element characteristics expected of plume melts.  This paradox can be explained by the process that mixes melts segregated from different depths of the melting column.  The resulting model provides insight into the processes governing melt compositions at spreading ridges.
C1 UNIV ICELAND,NORD VOLCANOL INST,IS-101 REYKJAVIK,ICELAND.
C3 University of Iceland
RP ELLIOTT, TR (corresponding author), OPEN UNIV,DEPT EARTH SCI,MILTON KEYNES MK7 6AA,BUCKS,ENGLAND.
NR 49
TC 153
Z9 157
U1 0
U2 18
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 201
EP 206
DI 10.1038/351201a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000046
DA 2026-03-10
ER

PT J
AU HARDARSON, BS
   FITTON, JG
AF HARDARSON, BS
   FITTON, JG
TI INCREASED MANTLE MELTING BENEATH SNAEFELLSJOKULL VOLCANO DURING LATE PLEISTOCENE DEGLACIATION
SO NATURE
LA English
DT Article
AB BASALTIC magmatism results when upwelling mantle crosses the peridotite solidus. The greater the overstep of the solidus, the greater the degree of mantle melting and the larger the volume of magma produced. In Iceland most of the active volcanism occurs along the central spreading axis, although some occurs in isolated off-axis volcanoes such as Snaefellsjokull. Because the mantle beneath Snaefellsjokull is not upwelling as vigorously as that beneath the spreading axis, it oversteps its solidus by a much smaller amount and consequently the degree of melting is less. The composition of the resulting magma will be much more sensitive to small perturbations in the amount of upwelling than will the mantle beneath the ridge axis. We show here that the reduction of pressure in the mantle caused by the unloading of ice was sufficient to affect magma composition. Unloading was accompanied by a clear shift towards less undersaturated magma compositions, which reflect a transient increase of about 0.5% in the degree of mantle melting, coupled with a decrease in depth of melting.
RP HARDARSON, BS (corresponding author), UNIV EDINBURGH,DEPT GEOL & GEOPHYS,W MAINS RD,EDINBURGH EH9 3JW,SCOTLAND.
NR 16
TC 93
Z9 122
U1 1
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 62
EP 64
DI 10.1038/353062a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500057
DA 2026-03-10
ER

PT J
AU DILLON, N
   GROSVELD, F
AF DILLON, N
   GROSVELD, F
TI HUMAN GAMMA-GLOBIN GENES SILENCED INDEPENDENTLY OF OTHER GENES IN THE BETA-GLOBIN LOCUS
SO NATURE
LA English
DT Article
ID transgenic mice; expression
AB ERYTHROPOIESIS during human development is characterized by switches in expression of beta-like globin genes during the transition from the embryonic through fetal to adult stages.  Activation and high-level expression of the genes is directed by the locus control region (LCR), located 5' to the epsilon-gene 1-3.  The location of the LCR and its role in directing high-level expression of the globin genes has led to the suggestion that competition from the beta-gene for interaction with the LCR has a major role in silencing the fetal gamma-genes during adult life 4,5.  We have now constructed lines of transgenic mice containing the human A-gamma-globin gene linked to the LCR.  We observe high-level expression of the transgene in the embryonic stages but silencing of the gene in adult animals.  We conclude that the gamma-gene is not deregulated by the presence of the LCR and that competition from the beta-gene is not required for silencing of the gamma-genes in adult life.  The silencing is therefore likely to be mediated by stage-specific factors binding to sequences immediately flanking the genes.
RP DILLON, N (corresponding author), NATL INST MED RES,RIDGEWAY,MILL HILL,LONDON NW7 1AA,ENGLAND.
NR 19
TC 168
Z9 178
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 252
EP 254
DI 10.1038/350252a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900065
PM 1706482
DA 2026-03-10
ER

PT J
AU FUJIWARA, H
   YONEZAWA, Y
AF FUJIWARA, H
   YONEZAWA, Y
TI PHOTOELECTRIC RESPONSE OF A BLACK LIPID-MEMBRANE CONTAINING AN AMPHIPHILIC AZOBENZENE DERIVATIVE
SO NATURE
LA English
DT Article
AB LIPID membranes containing dye molecules that respond to light, for example by photoisomerization, may provide the basis for artificial visual systems for use in optoelectronic devices and optical transducers. Here we describe such a membrane/dye system that generates an electrical signal in response to irradiation within a specific range of wavelengths. We incorporated an amphiphilic azobenzene derivative into the planar black lipid membrane formed from egg lecithin. When a d.c. voltage is applied across the modified membrane, transient current pulses are induced by alternate irradiation with ultraviolet and visible light. We interpret this photoelectric response as the result of changes in the membrane capacitance caused by cis-trans photoisomerization of the azobenzene derivative.
C1 KYOTO UNIV,FAC ENGN,DEPT IND CHEM,KYOTO 606,JAPAN.
C3 Kyoto University
NR 11
TC 48
Z9 49
U1 0
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 724
EP 726
DI 10.1038/351724a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100056
DA 2026-03-10
ER

PT J
AU HIRATA, M
   HAYASHI, Y
   USHIKUBI, F
   YOKOTA, Y
   KAGEYAMA, R
   NAKANISHI, S
   NARUMIYA, S
AF HIRATA, M
   HAYASHI, Y
   USHIKUBI, F
   YOKOTA, Y
   KAGEYAMA, R
   NAKANISHI, S
   NARUMIYA, S
TI CLONING AND EXPRESSION OF CDNA FOR A HUMAN THROMBOXANE-A2 RECEPTOR
SO NATURE
LA English
DT Article
ID human-platelets; activation; protein; distinct; binding; u44069; gtpase; cells
AB THROMBOXANE A2 is a very unstable arachidonate metabolite, yet a potent stimulator of platelet aggregation and a constrictor of vascular and respiratory smooth muscles 1.  It has been implicated as a mediator in diseases such as myocardial infarction, stroke and bronchial asthma 2. Using a stable analogue of this compound we recently purified the human platelet thromboxane A2 receptor to apparent homogeneity 3.  Using an oligonucleotide probe corresponding to its partial amino-acid sequence, we have obtained a complementary DNA clone encoding this receptor from human placenta and a partial clone from cultured human megakaryocytic leukaemia cells.  The placenta cDNA encodes a protein of 343 amino acids with seven putative transmembrane domains.  The protein expressed in COS-7 cells binds drugs with affinities identical to those of the platelet receptor, and that in Xenopus oocytes opens Ca2+-activated Cl- channel on agonist stimulation.  Northern blot analysis and nucleotide sequences of the two clones suggest that an identical species of the thromboxane A2 receptor is present in platelets and vascular tissues. This first report on the molecular structure of an eicosanoid receptor will promote the molecular pharmacology and pathophysiology of these bioactive compounds.
C1 KYOTO UNIV,FAC MED,DEPT IMMUNOL,KYOTO 606,JAPAN.
C3 Kyoto University
RP HIRATA, M (corresponding author), KYOTO UNIV,FAC MED,DEPT PHARMACOL,KYOTO 606,JAPAN.
NR 29
TC 679
Z9 740
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 617
EP 620
DI 10.1038/349617a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000062
PM 1825698
DA 2026-03-10
ER

PT J
AU BAGRODIA, S
   CHACKALAPARAMPIL, I
   KMIECIK, TE
   SHALLOWAY, D
AF BAGRODIA, S
   CHACKALAPARAMPIL, I
   KMIECIK, TE
   SHALLOWAY, D
TI ALTERED TYROSINE-527 PHOSPHORYLATION AND MITOTIC ACTIVATION OF P60C-SRC
SO NATURE
LA English
DT Article
ID overexpressed pp60c-src; protein-kinase; mitosis; transformation; sites; entry
AB The tyrosine kinase activity of p60c-src, the protein of the c-src gene, increase during mitosis 1,2; this may be important in initiating at least some of the cellular changes that occur during this phase of the cell cycle.  Although there is evidence that p60c-src is phosphorylated at several sites during mitosis, phosphorylation in vitro does not increase its kinase activity 2,3.  We now report that this kinase activity of a p60c-src mutant with residue tyrosine 527 changed to phenylanine does not change during the cell cycle, suggesting that changes in the phosphorylation state of this residue may be responsible for the activation of p60c-src at mitosis.  Although changes in phosphorylation at Tyr527 cannot be detected with the wild-type protein we find that phosphorylation at Tyr527 of a mutant with reduced kinase activity decreased threefold during mitosis.  On the basis of these results we suggest that activation of p60c-src at mitosis results from decreased phosphorylation on Tyr 527, and that p60c-src may be or may activate the kinase that phosphorylates Tyr 527.
C1 CORNELL UNIV,BIOCHEM MOLEC & CELL BIOL SECT,ITHACA,NY 14853.
   CORNELL UNIV,DEPT PATHOL,ITHACA,NY 14853.
C3 Cornell University; Cornell University
NR 17
TC 122
Z9 127
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 172
EP 175
DI 10.1038/349172a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800064
PM 1702522
DA 2026-03-10
ER

PT J
AU VINCENT, A
   HEITZ, D
   PETIT, C
   KRETZ, C
   OBERLE, I
   MANDEL, JL
AF VINCENT, A
   HEITZ, D
   PETIT, C
   KRETZ, C
   OBERLE, I
   MANDEL, JL
TI ABNORMAL PATTERN DETECTED IN FRAGILE-X PATIENTS BY PULSED-FIELD GEL-ELECTROPHORESIS
SO NATURE
LA English
DT Article
ID mental-retardation; mutation; inheritance; expression; markers; males
AB THE fragile-X syndrome is the most frequent inherited form of mental retardation, with an incidence of 1 in 1,500 males.  It is characterized by the presence of a fragile site at Xq27.3 induced in vitro by folate deprivation or by inhibitors of deoxynucleotide synthesis 1.  Its mode of inheritance is unusual for an X-linked trait, with incomplete penetrance in both males and females.  Some phenotypically normal males transmit the mutation to all their daughters who rarely express any symptoms, but penetrance is high in sons and daughters of these carrier women 2. Genetic and physical mapping of the Xq27-q28 region has confirmed that the disease locus is located at or very near the fragile site 3-6. Hypotheses proposed to account for the abnormalities in the inheritance of the disease include sequence rearrangements by meiotic recombination 1,7,8 or a mutation that affects reactivation of an inactive X chromosome during differentiation of female germ cells 9,10. To detect such rearrangements, or methylation changes that may reflect a locally inactive X chromosome, we used pulsed-field gel analysis of DNA from fragile-X patients with probes close to the fragile-X locus.  The probe Do33 (DXS465) detected abnormal patterns in fragile-X patients, but not in normal controls or in non-expressing male transmitters.
C1 FAC MED STRASBOURG,CNRS,GENET MOLEC EUCARYOTES LAB,INSERM,U184,F-67085 STRASBOURG,FRANCE.
   INST PASTEUR,UNITE RECOMBINAISON & EXPRESS GENET,F-75724 PARIS,FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS); Institut National de la Sante et de la Recherche Medicale (Inserm); Universites de Strasbourg Etablissements Associes; Universite de Strasbourg; Pasteur Network; Universite Paris Cite; Institut Pasteur Paris
NR 14
TC 199
Z9 211
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 624
EP 626
DI 10.1038/349624a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000064
PM 1672039
DA 2026-03-10
ER

PT J
AU KITAMURA, S
   SATO, T
   IWATSUKI, M
AF KITAMURA, S
   SATO, T
   IWATSUKI, M
TI OBSERVATION OF SURFACE RECONSTRUCTION ON SILICON ABOVE 800-DEGREES-C USING THE STM
SO NATURE
LA English
DT Article
ID phase-transition; si(111); 7x7
AB AN understanding of the kinetics of structural phase transitions in crystalline, semiconducting thin films is important for the control of film growth in techniques such as molecular-beam epitaxy, as well as in applications of such films at high temperatures.  Electron diffraction techniques (LEED and RHEED) have been applied to the study of high-temperature surface reconstruction, but although these can detect changes in surface periodicity, they do not permit atomic-scale resolution of the nucleation and growth processes.  The scanning tunnelling microscope (STM) provides an alternative tool to investigate changes of this sort, but high-temperature observations have been hampered by problems of thermal drift.  Here we report our success in overcoming these problems and thus in obtaining atomic-resolution STM images of the 1 x 1 --> 7 x 7 surface reconstruction of a silicon thin film at about 860-degrees-C.  Step formation and migration are clearly visible in these images.
RP KITAMURA, S (corresponding author), JEOL LTD,1-2 MUSASHINO 3-CHOME,TOKYO 196,JAPAN.
NR 9
TC 144
Z9 145
U1 0
U2 51
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 215
EP 217
DI 10.1038/351215a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000050
DA 2026-03-10
ER

PT J
AU MENKE, A
   JOCKUSCH, H
AF MENKE, A
   JOCKUSCH, H
TI DECREASED OSMOTIC STABILITY OF DYSTROPHIN-LESS MUSCLE-CELLS FROM THE MDX MOUSE
SO NATURE
LA English
DT Article
ID duchenne muscular-dystrophy; gene
AB HUMAN X-linked Duchenne and Becker muscular dystrophies are due to defects in dystrophin, the product of an exceptionally large gene1,2. Although dystrophin has been characterized as a spectrin-like3 submembranous4 cytoskeletal protein, there is no experimental evidence for its function in the structural maintenance of muscle5.  Current hypotheses attribute necrosis of hystrophin-less fibres in situ to mechanical weakening of the outer membrane6, to an excessive influx of Ca2+ ions7,8, or to a combination of these two mechanisms, possibly mediated by stretch-sensitive ion channels9.  Using hypo-osmotic shock to determine stress resistance10 and a mouse model (mdx)11,12 for the human disease, we show that functional dystrophin contributes to the stability of both cultured myotubes and isolated mature muscle fibres.
RP MENKE, A (corresponding author), UNIV BIELEFELD,DEV BIOL UNIT,W-4800 BIELEFELD 1,GERMANY.
NR 22
TC 299
Z9 320
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 69
EP 71
DI 10.1038/349069a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100053
PM 1985268
DA 2026-03-10
ER

PT J
AU HASTY, P
   RAMIREZSOLIS, R
   KRUMLAUF, R
   BRADLEY, A
AF HASTY, P
   RAMIREZSOLIS, R
   KRUMLAUF, R
   BRADLEY, A
TI INTRODUCTION OF A SUBTLE MUTATION INTO THE HOX-2.6 LOCUS IN EMBRYONIC STEM-CELLS
SO NATURE
LA English
DT Article
ID germ-line transmission; homologous recombination; es cells; gene; expression; murine; organization; disruption; regions
AB GENE targeting in embryonic stem (ES) cells is a powerful tool for generating mice with null alleles 1. Current methods of gene inactivation in ES cells introduce a neomycin gene (neo) cassette both as a mutagen and a selection marker for transfected cells 2-11. Although null alleles are valuable, changes at the nucleotide level of a gene are very important for functional analysis. One gene family in which subtle mutations would be particularly valuable are the clusters of Hox homeobox genes 12-16. Inactivation of genes in a cluster with a neo cassette that includes promoter/enhancer elements may deregulate transcription of neighbouring genes and generate a phenotype which is difficult to interpret. We describe here a highly efficient gene targeting method, termed the 'hit and run' procedure. This generates ES cells with subtle site-specific mutations with no selectable marker and may be useful for most genes. We have developed this procedure at the hypoxanthine phosphoribosyltransferase (hprt) locus and subsequently isolated ES cells with a premature stop codon in the homeobox of Hox-2.6 (ref. 14).
C1 BAYLOR UNIV, INST MOLEC GENET, 1 BAYLOR PLAZA, HOUSTON, TX 77030 USA.
   NATL INST MED RES, LONDON NW7 1AA, ENGLAND.
C3 Baylor University; Baylor College of Medicine; MRC National Institute for Medical Research
NR 27
TC 268
Z9 318
U1 0
U2 11
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 243
EP 246
DI 10.1038/350243a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900062
PM 1672446
DA 2026-03-10
ER

PT J
AU XIE, XM
   SMART, TG
AF XIE, XM
   SMART, TG
TI A PHYSIOLOGICAL-ROLE FOR ENDOGENOUS ZINC IN RAT HIPPOCAMPAL SYNAPTIC NEUROTRANSMISSION
SO NATURE
LA English
DT Article
ID pyramidal cells; brain; localization; release; neurons; zn-2+; responses
AB THE mammalian central nervous system (CNS) contains an abundance of the transition metal zinc, which is highly localized in the neuronal parenchyma 1-4. Zinc is actively taken up 5,6 and stored in synaptic vesicles in nerve terminals 7-10, and stimulation of nerve fibre tracts that contain large amounts of zinc, such as the hippocampal mossy fibre system 4, can induce its release 11-13, suggesting that it may act as a neuromodulator. The known interaction of zinc with the major excitatory and inhibitory amino-acid neurotransmitter receptors in the CNS supports this notion 14-16. That zinc has a role in CNS synaptic transmission, however, has so far not been shown. Here we report a physiological role for zinc in the young rat hippocampus (postnatal, P3-P14 days). Our results indicate that naturally occurring spontaneous giant depolarizing synaptic potentials (GDPs) in young CA3 pyramidal neurones, mediated by the release of GABA (gamma-aminobutyric acid) 17, are induced by endogenously released zinc. These synaptic potentials are inhibited by specific zinc-chelating agents. GDPs are apparently generated by an inhibitory action of zinc on both pre- and postsynaptic GABA(B) receptors in the hippocampus. Our study implies that zinc modulates synaptic transmission in the immature hippocampus, a finding that may have implications for understanding benign postnatal seizures in young children suffering with acute zinc deficiency 18.
C1 UNIV LONDON, DEPT PHARMACOL, 29-39 BRUNSWICK SQ, LONDON WC1N 1AX, ENGLAND.
C3 University of London
FU Wellcome Trust Funding Source: Medline
NR 30
TC 388
Z9 404
U1 1
U2 17
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 521
EP 524
DI 10.1038/349521a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100065
PM 1846946
DA 2026-03-10
ER

PT J
AU TANIGAKI, K
   EBBESEN, TW
   SAITO, S
   MIZUKI, J
   TSAI, JS
   KUBO, Y
   KUROSHIMA, S
AF TANIGAKI, K
   EBBESEN, TW
   SAITO, S
   MIZUKI, J
   TSAI, JS
   KUBO, Y
   KUROSHIMA, S
TI SUPERCONDUCTIVITY AT 33-K IN CSXRBYC60
SO NATURE
LA English
DT Article
ID c-60
AB THE synthesis of macroscopic quantities 1,2 of the fullerenes C60 and C70 has led to discoveries of several unusual properties 3-10, in particular the high conductivity 3 and superconductivity 4-6 of alkali-metal-doped phases. Here we report a superconducting phase of C60 doped with caesium and rubidium, which has the highest transition temperature T(c) and the largest diamagnetic shielding found so far for the alkali-metal-doped compounds. Cs(x)Rb(y)C60 (x = 2 and y = 1 in the dopant feed) exhibits a T(c) of 33 K and a diamagnetic shielding of over 60%. This is also the highest T(c) yet observed in a molecular superconductor. The variation of T(c) with dopant, T(c)(K(x)C60) [18 K] < T(c)(Rb(x)C60)[approximately 29 K] < T(c)(Cs(x)Rb(y)C60) [33 K], supports the interpretation that the transition temperature of these fullerides is determined mainly by the density of states at the Fermi level.
RP TANIGAKI, K (corresponding author), NEC CORP LTD,FUNDAMENTAL RES LABS,TSUKUBA 305,JAPAN.
NR 10
TC 884
Z9 915
U1 0
U2 122
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 222
EP 223
DI 10.1038/352222a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500057
DA 2026-03-10
ER

PT J
AU SHIODA, T
   LEVY, JA
   CHENGMAYER, C
AF SHIODA, T
   LEVY, JA
   CHENGMAYER, C
TI MACROPHAGE AND T-CELL LINE TROPISMS OF HIV-1 ARE DETERMINED BY SPECIFIC REGIONS OF THE ENVELOPE GP120 GENE
SO NATURE
LA English
DT Article
ID human immunodeficiency virus; aids-associated retrovirus; variants; type-1; expression; sequences; capacity
AB Strains of human immunodeficiency virus type 1 (HIV-1) display a high degree of biological heterogeneity which may be linked to certain clinical manifestations of AIDS.  They vary in their ability to infect different cell types 1-3, to replicate rapidly and to high titre in culture 4-6, to down-modulate the CD4 receptor 7,8, and to cause cytopathic changes in infected cells 7,9-11.  Some of these in vitro properties correlate with pathogenicity of the virus in vivo 11,12.  To map the viral determinants of the cellular host range of HIV-1, recombinant viruses were generated between biologically active molecular clones of HIV-1 isolates showing differences in infection of primary peripheral blood macrophages and established T-cell lines.  We report here at a specific region of the envelope gp120 gene representing 159 amino-acid residues of glycoprotein gp 120 seems to determine macrophage tropism, whereas an overlapping region representing 321 amino-acid residues determines T cell-line tropism.  These studies provide a basis for relating functional domains of the HIV-1 env gene to pathogenic potential.
RP SHIODA, T (corresponding author), UNIV CALIF SAN FRANCISCO,DEPT MED,CANC RES INST,SAN FRANCISCO,CA 94143, USA.
NR 26
TC 521
Z9 550
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 167
EP 169
DI 10.1038/349167a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800062
PM 1986308
DA 2026-03-10
ER

PT J
AU NADA, S
   OKADA, M
   MACAULEY, A
   COOPER, JA
   NAKAGAWA, H
AF NADA, S
   OKADA, M
   MACAULEY, A
   COOPER, JA
   NAKAGAWA, H
TI CLONING OF A COMPLEMENTARY-DNA FOR A PROTEIN-TYROSINE KINASE THAT SPECIFICALLY PHOSPHORYLATES A NEGATIVE REGULATORY SITE OF P60C-SRC
SO NATURE
LA English
DT Article
ID phospholipase-c; rat-brain; pp60c-src; gene; binding; virus; sequence; dephosphorylation; similarity; domains
AB THE protein-tyrosine kinase activity of the proto-oncogene product p60c-src is negatively regulated by the phosphorylation of a tyrosine residue close to the C terminus, tyrosine 527 (refs 1-11).  The phosphorylation might be catalysed by a so-far-unidentified tyrosine kinase, distinct from p60c-src (ref. 7).  Recently we purified a protein-tyrosine kinase that specifically phosphorylates tyrosine 527 of p60c-src from neonatal rat brain 8,12,13.  We have now confirmed the specificity of this enzyme by using a mutant p60c-src that has a phenylalanine instead of tyrosine 527, and cloned a complementary DNA that encodes the enzyme.  The enzyme is similar to kinases of the src family in that it has two conserved regions, Src-homology regions 2 and 3, upstream of a tyrosine kinase domain.  The amino-acid identity of each region is no more than 47%, however, and the enzyme lacks phosphorylation sites corresponding to tyrosines 416 and 527 of p60c-src and has no myristylation signal.  These results suggest that this protein-tyrosine kinase, which might negatively regulate p60c-src, represents a new type of tyrosine kinase.
C1 OSAKA UNIV,INST PROT RES,DIV PROT METAB,3-2 YAMADAOKA,SUITA,OSAKA 565,JAPAN.
   FRED HUTCHINSON CANC RES CTR,SEATTLE,WA 98104.
C3 University of Osaka; Fred Hutchinson Cancer Center
NR 32
TC 609
Z9 672
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 69
EP 72
DI 10.1038/351069a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300062
PM 1709258
DA 2026-03-10
ER

PT J
AU MUSSELWHITE, DS
   DRAKE, MJ
   SWINDLE, TD
AF MUSSELWHITE, DS
   DRAKE, MJ
   SWINDLE, TD
TI EARLY OUTGASSING OF MARS SUPPORTED BY DIFFERENTIAL WATER SOLUBILITY OF IODINE AND XENON
SO NATURE
LA English
DT Article
ID noble-gases; earth; meteorites; evolution; volatiles
AB THE martian atmosphere has a high Xe-129/Xe-132 ratio compared with any on Earth and most meteorites. The Xe-129/Xe-132 ratio in the martian atmosphere is also high relative to the martian mantle 1. In contrast, Earth's upper mantle has a higher Xe-129/Xe-132 ratio than its atmosphere 2.  As Xe-129 is the daughter product of the extinct nuclide I-129, a means of fractionating iodine from xenon early in martian history appears necessary to account for the Xe-129/Xe-132 ratios of its known reservoirs. Crystal/melt partitioning will fractionate iodine from xenon in the right sense, but the fractionation is probably inadequate in magnitude; differences in the silicate melt solubilities of iodine and xenon would cause fractionation in the wrong direction. Here we present a model to account for the martian xenon data which relies on the very different solubilities of the two elements in water to fractionate them after outgassing. Atmospheric xenon is lost by impact erosion during heavy bombardment, followed by release of X-129 produced from I-129 decay in the crust.
RP MUSSELWHITE, DS (corresponding author), UNIV ARIZONA,DEPT PLANETARY SCI,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA.
NR 20
TC 33
Z9 34
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 697
EP 699
DI 10.1038/352697a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400050
DA 2026-03-10
ER

PT J
AU FLANAGAN, PM
   KELLEHER, RJ
   SAYRE, MH
   TSCHOCHNER, H
   KORNBERG, RD
AF FLANAGAN, PM
   KELLEHER, RJ
   SAYRE, MH
   TSCHOCHNER, H
   KORNBERG, RD
TI A MEDIATOR REQUIRED FOR ACTIVATION OF RNA POLYMERASE-II TRANSCRIPTION INVITRO
SO NATURE
LA English
DT Article
ID preinitiation complex; gal4 derivatives; factor atf; yeast; gene; initiation; mechanism; binding; promoters; interacts
AB ACTIVATOR proteins bind to enhancer DNA elements and stimulate the initiation of transcription.  It has been proposed 1-3 that activators contact general initiation factors at a promoter, and evidence for such direct interaction has been obtained 4-10.  Studies of transcription in vitro, however, have suggested that activators might function through an intermediary molecule(s) distinct from the general factors.  In the first of these studies 11,12, we exploited the finding that one activator could inhibit transcription stimulated by a second activator (activator interference or 'squelching') 13-15.  This inhibition, which is attributed to competition between the activators for a common target factor, could not be relieved by addition of a large excess of general initiation factors, suggesting that the target for which activators compete is distinct from these factors.  Similar conclusions came from the observation that TFIID's expressed from cloned genes 16-18 fail to replace partially purified 'natural' TFIID fractions in supporting activation, evidently because they lacked some component present in the impure fractions.  While these lines of evidence for a novel 'mediator' of activation were negative, we also showed that a partially purified fraction from yeast would reverse activator interference 12.  This positive effect of a presumptive mediator provided an assay for its activity, but its role in activation was still only inferred.  We now present direct evidence for a mediator which is required for stimulation of transcription in vitro by the activators GAL4-VP16 and GCN4, but which has no effect on transcription in the absence of activator protein.
RP FLANAGAN, PM (corresponding author), STANFORD UNIV,MED CTR,SCH MED,FAIRCHILD CTR,DEPT CELL BIOL,STANFORD,CA 94305, USA.
NR 27
TC 310
Z9 377
U1 0
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 436
EP 438
DI 10.1038/350436a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200055
PM 2011193
DA 2026-03-10
ER

PT J
AU GODIN, I
   DEED, R
   COOKE, J
   ZSEBO, K
   DEXTER, M
   WYLIE, CC
AF GODIN, I
   DEED, R
   COOKE, J
   ZSEBO, K
   DEXTER, M
   WYLIE, CC
TI EFFECTS OF THE STEEL GENE-PRODUCT ON MOUSE PRIMORDIAL GERM-CELLS IN CULTURE
SO NATURE
LA English
DT Article
ID tyrosine kinase receptor; c-kit; growth-factor; w-locus; proto-oncogene; si-locus; expression; ligand; rat
AB MUTATIONS at the steel (sl) and dominant white spotting (W) loci in the mouse affect primordial germ cells (PGC), melanoblasts and haemopoietic stem cells 1.  The W gene encodes a cell-surface receptor of the tyrosine kinase family 2,3, the proto-oncogene c-kit.  In situ analysis has shown c-kit messenger RNA expression in PGC in the early genital ridges 4.  The Sl gene encodes the ligand for this receptor, a peptide growth factor, called here stem cell factor (SCF) 5-7.  SCF mRNA is expressed in many regions of the early mouse embryo, including the areas of migration of these cell types 8.  It is important now to identify the role of the Sl-W interaction in the development of these migratory embryonic stem cell populations.  Using an in vitro assay system 9, we show that SCF increases both the overall numbers and colony sizes of migratory PGC isolated from wild-type mouse embryos, and cultured on irradiated feeder layers of STO cells (a mouse embryonic fibroblast line).  In the absence of feeder cells, SCF causes a large increase in the initial survival and apparent motility of PGC in culture.  But labelling with bromodeoxyuridine shows that SCF is not, by itself, a mitogen for PGC.  SCF does not exert a chemotropic effect on PGC in in vitro assays.  These results suggest that SCF in vivo is an essential requirement for PGC survival.  This demonstrates the control of the early germ-line population by a specific trophic factor.
C1 UNIV CAMBRIDGE,DEPT ZOOL,CAMBRIDGE CB2 1QR,ENGLAND.
   CHRISTIE HOSP & HOLT RADIUM INST,PATERSON INST CANC RES,DEPT EXPTL HAEMATOL,MANCHESTER M20 9BX,LANCS,ENGLAND.
   AMGEN INC,AMGEN CTR,THOUSAND OAKS,CA 91320.
C3 University of Cambridge; Paterson Institute for Cancer Research; Christie NHS Foundation Trust; Christie Hospital; Amgen
RP GODIN, I (corresponding author), UNIV CAMBRIDGE,WELLCOME CANC RES CAMPAIGN INST,TENNIS COURT RD,CAMBRIDGE CB2 1QR,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 15
TC 376
Z9 409
U1 1
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 807
EP 809
DI 10.1038/352807a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400061
PM 1715517
DA 2026-03-10
ER

PT J
AU BRZOZOWSKI, AM
   DEREWENDA, U
   DEREWENDA, ZS
   DODSON, GG
   LAWSON, DM
   TURKENBURG, JP
   BJORKLING, F
   HUGEJENSEN, B
   PATKAR, SA
   THIM, L
AF BRZOZOWSKI, AM
   DEREWENDA, U
   DEREWENDA, ZS
   DODSON, GG
   LAWSON, DM
   TURKENBURG, JP
   BJORKLING, F
   HUGEJENSEN, B
   PATKAR, SA
   THIM, L
TI A MODEL FOR INTERFACIAL ACTIVATION IN LIPASES FROM THE STRUCTURE OF A FUNGAL LIPASE-INHIBITOR COMPLEX
SO NATURE
LA English
DT Article
ID miehei triglyceride lipase; transition-state analog; macromolecular structures; venom phospholipase-a2; pancreatic lipase; crystal-structure; refinement; crystallography
AB LIPASES are hydrolytic enzymes which break down triacylglycerides into free fatty acids and glycerols. They have been classified as serine hydrolases owing to their inhibition by diethyl p-nitrophenyl phosphate 1. Lipase activity is greatly increased at the lipid-water interface 2,3, a phenomenon known as interfacial activation. X-ray analysis has revealed the atomic structures of two triacylglycerol lipases, unrelated in sequence: the human pancreatic lipase (hPL) 4, and an enzyme isolated from the fungus Rhizomucor (formerly Mucor) miehei 5 (RmL). In both enzymes the active centres contain structurally analogous Asp-His-Ser triads (characteristic of serine proteinases), which are buried completely beneath a short helical segment, or 'lid'. Here we present the crystal structure (at 3 angstrom resolution) of a complex of R. miehei lipase with n-hexylphosphonate ethyl ester in which the enzyme's active site is exposed by the movement of the helical lid. This movement also increases the nonpolarity of the surface surrounding the catalytic site. We propose that the structure of the enzyme in this complex is equivalent to the activated state generated by the oil-water interface.
C1 UNIV ALBERTA, DEPT BIOCHEM,MRC,PROT STRUCT & FUNCT GRP, 474 MED SCI BLDG, EDMONTON T6G 2H7, ALBERTA, CANADA.
   UNIV YORK, DEPT CHEM, YORK YO1 5DD, N YORKSHIRE, ENGLAND.
   UNIV LODZ, INST CHEM, DEPT CRYSTALLOG, PL-91416 LODZ, POLAND.
C3 University of Alberta; University of York - UK; University of Lodz
NR 26
TC 1071
Z9 1137
U1 2
U2 224
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 491
EP 494
DI 10.1038/351491a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800059
PM 2046751
DA 2026-03-10
ER

PT J
AU HUNT, P
   GULISANO, M
   COOK, M
   SHAM, MH
   FAIELLA, A
   WILKINSON, D
   BONCINELLI, E
   KRUMLAUF, R
AF HUNT, P
   GULISANO, M
   COOK, M
   SHAM, MH
   FAIELLA, A
   WILKINSON, D
   BONCINELLI, E
   KRUMLAUF, R
TI A DISTINCT HOX CODE FOR THE BRANCHIAL REGION OF THE VERTEBRATE HEAD
SO NATURE
LA English
DT Article
ID homeobox-containing gene; mouse hindbrain; expression; murine; segmentation; organization; hox-5.1; hox-2.6; domains; hox-1.5
AB THE branchial region of the vertebrate head forms through complex interactions involving rhombomeric segments, neural crest and branchial arches 1. It is thought that aspects of their patterning mechanisms are linked 2 and involve Hox-2 genes, whose overlapping and spatially restricted expression domains represent a combinatorial code for generating regional diversity 3-5. Vertebrates possess four Hox clusters of Antennapedia class homeobox genes, related to each other by duplication and divergence from a common ancestral complex 3,6-8. In consequence, at equivalent positions in different clusters there are highly related genes known as subfamilies or paralogous groups. As Hox-2 genes cannot fully account for patterning individual rhombomeres, we investigated whether offsets in expression limits of paralogous genes could account for the generation of regional diversity. We report here that, with the exception of the labial subfamily, paralogues show identical expression limits in rhombomeres, cranial ganglia and branchial arches, providing a combinatorial Hox code for the branchial region that seems to be different in organization to that of the trunk.
C1 NATL INST MED RES, MRC, EUKARYOT MOLEC GENET LAB, RIDGEWAY, LONDON NW7 1AA, ENGLAND.
   CNR, INT INST GENET & BIOPHYS, NAPLES, ITALY.
C3 Consiglio Nazionale delle Ricerche (CNR); Istituto di Genetica e Biofisica Adriano Buzzati-Traverso (IGB-CNR)
NR 39
TC 467
Z9 506
U1 0
U2 13
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 861
EP 864
DI 10.1038/353861a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200065
PM 1682814
DA 2026-03-10
ER

PT J
AU ROBINSON, DR
   GULL, K
AF ROBINSON, DR
   GULL, K
TI BASAL BODY MOVEMENTS AS A MECHANISM FOR MITOCHONDRIAL GENOME SEGREGATION IN THE TRYPANOSOME CELL-CYCLE
SO NATURE
LA English
DT Article
ID brucei-brucei; microtubules; invitro
AB THE mitochondrial genome of Trypanosoma brucei is organized in the form of a complex catenated network of circular DNA molecules. This mass of DNA, known as the kinetoplast, is present at a unique site in the single mitochondrion, and is replicated in a discrete, periodic S phase of the cell cycle. The single-copy nature of the kinetoplast suggests that there is a mechanism ensuring segregation fidelity of replicated copies to each daughter cell. Historically, speculation regarding the nature of this mechanism has often attributed significance to the close association between the kinetoplast and the flagellum basal body. We provide here direct evidence that this mitochondrial DNA complex is indeed linked to the basal body, and segregation of the kinetoplast DNA is dependent on a microtubule-mediated separation of the new and old flagellar basal bodies during the cell cycle. This unique system may represent the remnants of an evolutionarily archaic mechanism for genome segregation.
C1 UNIV MANCHESTER, SCH MED, DEPT BIOCHEM & MOLEC BIOL, OXFORD RD, MANCHESTER M13 9PT, LANCS, ENGLAND.
C3 University of Manchester
NR 16
TC 272
Z9 297
U1 0
U2 10
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 731
EP 733
DI 10.1038/352731a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400064
PM 1876188
DA 2026-03-10
ER

PT J
AU GVIRTZMAN, H
   GORELICK, SM
AF GVIRTZMAN, H
   GORELICK, SM
TI DISPERSION AND ADVECTION IN UNSATURATED POROUS-MEDIA ENHANCED BY ANION EXCLUSION
SO NATURE
LA English
DT Article
ID transport; water; diffusion; movement; soils; flow
AB IT has been observed 1-4 that the average transport velocity of dissolved anions through soils may be larger than that of the accompanying water molecules, owing to electrostatic repulsion by negatively charged solid surfaces, which forces the anions into pore centres where the velocity is faster.  This phenomenon, known as anion exclusion, has been explained by diffusive double-layer theory 5-7.  Here we present analyses and numerical modelling of concentration/depth profiles of tritium, chloride and sulphate which were collected from irrigated land in the Israeli coastal plain.  We found that the anions travelled at about twice the velocity of tritium.  The behaviour of tritium is consistent with advective-diffusive transport, but the values of the dispersion coefficients associated with anion transport greatly exceeded the values expected for molecular diffusion in a porous medium, and were approximately 30 times those found for tritium transport.  Our results indicate that anion exclusion restricts the number of active pore networks available for anion transport.  We present two conceptual models that can explain the observed results-in one model some porous regions are completely blocked, whereas in the other they are only partially blocked.
C1 STANFORD UNIV,DEPT APPL EARTH SCI,STANFORD,CA 94305.
C3 Stanford University
NR 22
TC 65
Z9 73
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 793
EP 795
DI 10.1038/352793a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400056
DA 2026-03-10
ER

PT J
AU CHOWRIRA, BM
   BERZALHERRANZ, A
   BURKE, JM
AF CHOWRIRA, BM
   BERZALHERRANZ, A
   BURKE, JM
TI NOVEL GUANOSINE REQUIREMENT FOR CATALYSIS BY THE HAIRPIN RIBOZYME
SO NATURE
LA English
DT Article
ID tobacco ringspot virus; t7 rna-polymerase; satellite rna; sequence; cleavage
AB THERE is much interest in the development of 'designer ribozymes' to target destruction of RNAs in vitro and in vivo 1. Engineering of ribozymes with novel specificities requires detailed knowledge of the ribozyme-substrate interaction, and a rigorous evaluation of sequence specificity. The hairpin ribozyme catalyses an efficient and reversible site-specific cleavage reaction 2-4. We have used mutagenesis and in vitro selection strategies to show that RNA cleavage and ligation has an absolute requirement for guanosine immediately 3' to the cleavage-ligation site. This G is not required for efficient substrate binding, rather, its 2-amino group is an essential component of the active site required for catalysis.
C1 UNIV VERMONT, MARKEY CTR MOLEC GENET, DEPT MICROBIOL & MOLEC GENET, BURLINGTON, VT 05405 USA.
C3 University of Vermont
NR 18
TC 143
Z9 167
U1 0
U2 5
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 320
EP 322
DI 10.1038/354320a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400052
PM 1956383
DA 2026-03-10
ER

PT J
AU AMANN, R
   SPRINGER, N
   LUDWIG, W
   GORTZ, HD
   SCHLEIFER, KH
AF AMANN, R
   SPRINGER, N
   LUDWIG, W
   GORTZ, HD
   SCHLEIFER, KH
TI IDENTIFICATION INSITU AND PHYLOGENY OF UNCULTURED BACTERIAL ENDOSYMBIONTS
SO NATURE
LA English
DT Article
ID paramecium-caudatum; holospora-elegans; obtusa; probes; forms; cells; dna
AB THE use of Koch's technique to isolate bacteria in pure cultures has enabled thousands of bacterial species to be characterized.  But for the many microorganisms that have never been cultivated, DNA amplification in vitro using the polymerase chain reaction is now making their genes accessible 1-3.  Here we use this technique to study bacteria of the genus Holospora, which live in ciliates 4 and whose phylogenetic relationship has remained unknown because they are impossible to cultivate.  Species of Holospora are highly infectious 5-7 and live in the nuclei of their specific host cells:  H. elegans and H. undulata infect micronuclei of Paramecium caudatum 8, whereas H. obtusa infects the macronucleus in other strains of the same host species 9; Holospora species have a common developmental cycle 10-13.  We have amplified, cloned and sequenced gene fragments encoding ribosomal RNA of H. obtusa.  The phylogenetic position of H. obtusa in the alpha-group of Proteobacteria was determined by 16S rRNA sequence analysis.  The sequences were then used to design species- as well as genus-specific rRNA hybridization probes, which enabled us to detect and differentiate individual cells of the endosymbionts in situ.  The large amount of rRNA in the cells indicates a high physiological activity of the endosymbionts in the host nuclei.
C1 UNIV MUNSTER,INST ZOOL,W-4400 MUNSTER,GERMANY.
C3 University of Munster
RP AMANN, R (corresponding author), TECH UNIV MUNICH,LEHRSTUHL MIKROBIOL,ARCISSTR 21,W-8000 MUNICH 2,GERMANY.
NR 30
TC 294
Z9 305
U1 0
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 161
EP 164
DI 10.1038/351161a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500056
PM 1709451
DA 2026-03-10
ER

PT J
AU COUVES, JW
   THOMAS, JM
   WALLER, D
   JONES, RH
   DENT, AJ
   DERBYSHIRE, GE
   GREAVES, GN
AF COUVES, JW
   THOMAS, JM
   WALLER, D
   JONES, RH
   DENT, AJ
   DERBYSHIRE, GE
   GREAVES, GN
TI TRACING THE CONVERSION OF AURICHALCITE TO A COPPER CATALYST BY COMBINED X-RAY ABSORPTION AND DIFFRACTION
SO NATURE
LA English
DT Article
ID methanol; exafs
AB EVER since X-ray sources first became available, the merit of deploying diffraction and absorption spectroscopic studies simultaneously has been acknowledged 1. Information on oxidation states and local (approximately 6-angstrom radius) atomic environments is now obtained routinely from X-ray absorption measurements using synchrotron sources 2-4. Synchrotron radiation is also used commonly for high-resolution powder diffraction crystallography. We report here an instrumental arrangement that has allowed us to extract quantitative short- and long-range structural information on samples undergoing chemical change by measuring X-ray absorption spectra and X-ray diffraction patterns in situ and within a few seconds of one another, using a synchrotron X-ray source. To illustrate the combination of these techniques, we have followed the structural and chemical changes that occur within the layered mineral aurichalchite (Cu5-xZnx(OH)6(CO3)2) when heated in dry air to approximately 450-degrees-C. Despite marked changes in crystallinity, the local environment and electronic state of the CU2+ ions remain unchanged, even when at approximately 450-degrees-C the material is converted to a mixture of CuO and ZnO. Heating this mixture in H-2/N2 produces an active catalyst for the water-gas shift reaction (CO2 + H-2 --> CO + H2O), which our studies show to consist of small particles of copper metal (with some zinc incorporated) supported on ZnO.
C1 UCL ROYAL INST GREAT BRITAIN, DAVY FARADAY RES LAB, 21 ALBERMARLE ST, LONDON W1X 4BS, ENGLAND.
   SERC, DARESBURY LAB, WARRINGTON WA4 4AD, CHESHIRE, ENGLAND.
C3 University of London; University College London; STFC Daresbury Laboratory
RP THOMAS, JM (corresponding author), UCL ROYAL INST GREAT BRITAIN, DAVY FARADAY RES LAB, 21 ALBERMARLE ST, LONDON W1X 4BS, ENGLAND.
NR 15
TC 199
Z9 204
U1 0
U2 69
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 465
EP 468
DI 10.1038/354465a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800055
DA 2026-03-10
ER

PT J
AU WARD, RHR
   CAPON, DJ
   JETT, CM
   MURTHY, KK
   MORDENTI, J
   LUCAS, C
   FRIE, SW
   PRINCE, AM
   GREEN, JD
   EICHBERG, JW
AF WARD, RHR
   CAPON, DJ
   JETT, CM
   MURTHY, KK
   MORDENTI, J
   LUCAS, C
   FRIE, SW
   PRINCE, AM
   GREEN, JD
   EICHBERG, JW
TI PREVENTION OF HIV-1 IIIB INFECTION IN CHIMPANZEES BY CD4 IMMUNOADHESIN
SO NATURE
LA English
DT Article
ID human-immunodeficiency-virus; recombinant soluble cd4; type-1; immunization
AB THE first step in infection by the human immunodeficiency virus (HIV) is the specific binding of gp120, the envelope glycoprotein of HIV, to its cellular receptor, CD4 (see ref. 1 for review). To inhibit this interaction, soluble CD4 analogues that compete for gp120 binding and block HIV infection in vitro have been developed 2-8.  To determine whether these analogues can protect an uninfected individual from challenge with HIV, we used the chimpanzee model system of cell-free HIV infection. Chimpanzees are readily infected with the IIIB strain of HIV-1, becoming viraemic within about 4-6 weeks of challenge, although they do not develop the profound CD4+ T-cell depletion and immunodeficiency characteristic of HIV infection in humans 9.  CD4 immunoadhesin (CD4-IgG), a chimaeric molecule consisting of the N-terminal two immunoglobulin-like regions of CD4 joined to the Fc region of human IgG1 (refs 8, 10), was selected as the CD4 analogue for testing because it has a longer half-life than CD4, contributed by the IgG Fc portion of the molecule. In humans, this difference results in a 25-fold increased concentration of CD4-IgG in the blood compared with recombinant CD4 (ref. 11). Here we report that pretreatment with CD4-IgG can prevent the infection of chimpanzees with HIV-1. The need for a preventative agent is particularly acute in perinatal HIV transmission. As recombinant CD4-IgG, like the parent IgG molecule, efficiently crosses the primate placenta 10, it may be possible to set up an immune state in a fetus before HIV transfer occurs, thus preventing infection.
C1 CELL GENESYS INC,FOSTER CITY,CA 94404.
   SW FDN BIOMED RES,SAN ANTONIO,TX 78284.
   NEW YORK BLOOD CTR,LINDSLEY F KIMBALL RES INST,NEW YORK,NY 10021.
C3 Cell Genesys Inc; Texas Biomedical Research Institute; New York Blood Center
RP WARD, RHR (corresponding author), GENENTECH INC,460 PT SAN BRUNO BLVD,S SAN FRANCISCO,CA 94080, USA.
NR 23
TC 60
Z9 71
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 434
EP 436
DI 10.1038/352434a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600066
PM 1907354
DA 2026-03-10
ER

PT J
AU TIMSIT, Y
   VILBOIS, E
   MORAS, D
AF TIMSIT, Y
   VILBOIS, E
   MORAS, D
TI BASE-PAIRING SHIFT IN THE MAJOR GROOVE OF (CA)N TRACTS BY B-DNA CRYSTAL-STRUCTURES
SO NATURE
LA English
DT Article
ID a-dna; sequences; conformation; refinement; hydration; mutation; mismatch; exchange
AB THE crystal packing of the B-DNA dodecamer d(ACCGGCGCCACA). d(TGTGGCGCCGGT) is characterized by the reciprocal fit of double helices with specific base-backbone interactions in the major groove. Cooling the crystals below -10-degrees-C stabilizes a new conformational state with a long-range sequence-dependent one-step shift in the major-groove base pairing. The tilt of the bases leads to the disruption of the Watson-Crick pairing in the major groove and to the formation of interactions with the 5' neighbour of their complement. This alteration propagates along the helical axis over more than half a turn. As a result, the molecular structure is normal when seen from the minor groove side and mismatched in the major groove. Comparison with a parent isomorphous dodecamer structure corresponding to the codon 10-13 of the c-Ha-ras proto-oncogene shows that this new structural feature is sequence dependent and clearly favoured by (CA)n tracts. As(CA)n tracts of DNA are involved both in recombination and in transcription, this new recognition pattern should be considered in the analysis of the various processes involving the reading of the genetic information.
RP TIMSIT, Y (corresponding author), INST BIOL MOLEC & CELLULAIRE,CRISTALLOG BIOL LAB,15 RUE DESCARTES,F-67000 STRASBOURG,FRANCE.
NR 27
TC 97
Z9 98
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 167
EP 170
DI 10.1038/354167a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000066
PM 1944598
DA 2026-03-10
ER

PT J
AU HERNQUIST, L
   BARNES, JE
AF HERNQUIST, L
   BARNES, JE
TI ORIGIN OF KINEMATIC SUBSYSTEMS IN ELLIPTIC GALAXIES
SO NATURE
LA English
DT Article
AB ELLIPTICAL galaxies were once thought to be smooth, featureless stellar systems with little or no substructure, but increasingly sophisticated observations are challenging this point of view. Some ellipticals contain small central disks which may be counter-rotating or otherwise kinematically decoupled from the rest of the galaxy 1-6. It seems unlikely that these disks could form during the monolithic collapse of a slowly rotating proto-galaxy, as the most plausible outcome of such evolution is a system with a simple rotation pattern. Like other kinds of fine structure in elliptical galaxies 7, these subsystems have been widely interpreted as evidence for multiple formation events or episodes. Here we demonstrate the formation of a counter-rotating central gas disk in a merger of two gas-rich disk galaxies of equal mass. Such a structure may well account for the unusual gas kinematics found in the merger remnant NGC7252 (refs 8, 9). Continued star formation in such gaseous disks may produce central components with decoupled kinematics, resembling the cores of some elliptical galaxies.
C1 UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA.
C3 University of Hawaii System
RP HERNQUIST, L (corresponding author), UNIV CALIF SANTA CRUZ, LICK OBSERV, SANTA CRUZ, CA 95064 USA.
NR 34
TC 198
Z9 206
U1 0
U2 0
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 210
EP 212
DI 10.1038/354210a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800041
DA 2026-03-10
ER

PT J
AU OREGAN, B
   GRATZEL, M
AF OREGAN, B
   GRATZEL, M
TI A LOW-COST, HIGH-EFFICIENCY SOLAR-CELL BASED ON DYE-SENSITIZED COLLOIDAL TIO2 FILMS
SO NATURE
LA English
DT Article
ID photoelectrochemical conversion; electrochemistry; complexes; light; photochemistry; electricity; electrodes
AB THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods 1. Here we describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency. The device is based on a 10-mu-m-thick, optically transparent film of titanium dioxide particles a few nanometres in size, coated with a monolayer of a charge-transfer dye to sensitize the film for light harvesting. Because of the high surface area of the semiconductor film and the ideal spectral characteristics of the dye, the device harvests a high proportion of the incident solar energy flux (46%) and shows exceptionally high efficiencies for the conversion of incident photons to electrical current (more than 80%). The overall light-to-electric energy conversion yield is 7.1-7.9% in simulated solar light and 12% in diffuse daylight. The large current densities (greater than 12 mA cm-2) and exceptional stability (sustaining at least five million turnovers without decomposition), as well as the low cost, make practical applications feasible.
C1 SWISS FED INST TECHNOL, INST PHYS CHEM, CH-1015 LAUSANNE, SWITZERLAND.
C3 Swiss Federal Institutes of Technology Domain; Ecole Polytechnique Federale de Lausanne
NR 19
TC 26388
Z9 28764
U1 56
U2 9144
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 737
EP 740
DI 10.1038/353737a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600062
DA 2026-03-10
ER

PT J
AU BOLLAG, G
   MCCORMICK, F
AF BOLLAG, G
   MCCORMICK, F
TI DIFFERENTIAL REGULATION OF RASGAP AND NEUROFIBROMATOSIS GENE-PRODUCT ACTIVITIES
SO NATURE
LA English
DT Article
ID gtpase-activating protein; type-1 gene; gap; p21; domain; stimulation; interacts; encodes; cloning; lipids
AB THE ras-encoded p21ras proteins bind GTP very tightly, but catalyse hydrolysis to GDP very slowly 1.  In humans, two genes encode proteins that stimulate this GTPase activity (GAP, or GTPase-activating proteins)2, one of relative molecular mass 120,000, referred to as p120-GAP, and another NF1-GAP, which is encoded by the neurofibromatosis type-1 gene 3-5.  Both GAPs are widely expressed in mammalian tissues 6,7.  Here we show that although they will both bind oncogenic mutants of p21ras, neither will stimulate their GTPase activity.  NF1-GAP binds to the p21ras proteins up to 300 times more efficiently than p120-GAP.  The two GAPs are inhibited to different extents  by certain lipids:  micromolar concentrations of arachidonate, phosphatidate and phosphatidylinositol-4,5-bisphosphate affect only NF1-GAP.  This inhibition does not compete with p21ras, and lipid-inactivated NF1-GAP can still bind p21ras.  We used the detergent dodecyl maltoside, which inhibits only NF1-GAP, to distinguish between the two activities in cell extracts and found both types present together in several mammalian cell lines.  In contrast, GAP activity in extracts of Xenopus oocytes was not affected by dodecyl maltoside.  By these criteria, the mammalian cells contain both GAP activities and the oocytes have only p120-like GAP activity.  These results indicate that more than one GAP regulates p21ras in the same cell.
RP BOLLAG, G (corresponding author), CETUS CORP,DEPT MOLEC BIOL,1400 53RD ST,EMERYVILLE,CA 94608, USA.
NR 24
TC 317
Z9 350
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 576
EP 579
DI 10.1038/351576a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400062
PM 1904555
DA 2026-03-10
ER

PT J
AU TURSKI, L
   BRESSLER, K
   RETTIG, KJ
   LOSCHMANN, PA
   WACHTEL, H
AF TURSKI, L
   BRESSLER, K
   RETTIG, KJ
   LOSCHMANN, PA
   WACHTEL, H
TI PROTECTION OF SUBSTANTIA-NIGRA FROM MPP+ NEUROTOXICITY BY N-METHYL-D-ASPARTATE ANTAGONISTS
SO NATURE
LA English
DT Article
ID excitatory amino-acids; mouse-brain; parkinsons-disease; rat; glutamate; neurons; mptp; n-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine; 1-methyl-4-phenylpyridinium
AB INTAKE of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) leads to symptoms of Parkinson's disease and produces degeneration of nigrostriatal dopaminergic neurons in humans, giving rise to the hypothesis that this disorder may be caused by endogenous or environmental toxins 1-3.  Excitation mediated by dicarboxylic amino acids such as L-glutamate or L-aspartate, has been claimed to be involved in pathogenesis of neurodegenerative disorders 4.  We therefore sought to determine whether antagonists active at the NMDA or quisqualate subtypes of L-glutamate receptors prevent toxicity of either MPP+ (1-m ethyl-4-phenyl-pyridinium ion 5, the active metabolite of MPTP 6) or the selective dopaminergic neurotoxin 6-OHDA in the rat substantia nigra pars compacta.  We report here that certain selective NMDA antagonists (AP7, CPP, MK-801) 7, but not the preferential quisqualate antagonists CNQX and NBQX, 8 provided short-term (up to 24 h) protection against MPP+ toxicity when coadministered into the substantia nigra. Systemic administration of CPP or MK-801 also offered temporary protection for up to 4 h against MPP+ toxicity.  Repeated systemic administration of either compound prolonged protection against MPP+ challenge.  Repeated administration for at least 24 h also led to permanent protection, still evident 7 days after intranigral administration of MPP+.
RP TURSKI, L (corresponding author), SCHERING AG,RES LABS,W-1000 BERLIN 65,GERMANY.
NR 35
TC 544
Z9 581
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 414
EP 418
DI 10.1038/349414a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400051
PM 1846943
DA 2026-03-10
ER

PT J
AU SCHAFER, DA
   GELLES, J
   SHEETZ, MP
   LANDICK, R
AF SCHAFER, DA
   GELLES, J
   SHEETZ, MP
   LANDICK, R
TI TRANSCRIPTION BY SINGLE MOLECULES OF RNA-POLYMERASE OBSERVED BY LIGHT-MICROSCOPY
SO NATURE
LA English
DT Article
ID ternary complexes; movements; tracking
AB THE kinetics of transcription by Escherichia coli RNA polymerase relate directly to the regulation of transcription and to the properties of processive enzymes in general 1, but analysis of RNA polymerase movement along the DNA template has so far been limited to the study of populations of enzyme molecules. The ability to view nanometre-sized particles with the light microscope 2,3 suggested a method of monitoring transcription by individual RNA polymerase molecules. We describe here the behaviour of 40-nm-diameter particles of colloidal gold attached to the ends of DNA molecules being transcribed by RNA polymerase immobilized on a glass surface. The tethered gold particles are released from the surface at times after addition of nucleoside triphosphates that are consistent with the kinetics of transcription by RNA polymerase in solution. Analysis of the brownian motion of the gold particles enabled us to measure the movement along the template DNA of individual polymerase molecules.
C1 WASHINGTON UNIV,DEPT CELL BIOL,ST LOUIS,MO 63130.
   WASHINGTON UNIV,DEPT BIOL,ST LOUIS,MO 63130.
   DUKE UNIV,MED CTR,DEPT CELL BIOL,DURHAM,NC 27710.
   BRANDEIS UNIV,GRAD DEPT BIOCHEM,WALTHAM,MA 02254.
   BRANDEIS UNIV,CTR COMPLEX SYST,WALTHAM,MA 02254.
C3 Washington University (WUSTL); Washington University (WUSTL); Duke University; Brandeis University; Brandeis University
NR 13
TC 252
Z9 307
U1 0
U2 31
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 444
EP 448
DI 10.1038/352444a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600070
PM 1861724
DA 2026-03-10
ER

PT J
AU LIU, ZC
   AMBROS, V
AF LIU, ZC
   AMBROS, V
TI ALTERNATIVE TEMPORAL CONTROL-SYSTEMS FOR HYPODERMAL CELL-DIFFERENTIATION IN CAENORHABDITIS-ELEGANS
SO NATURE
LA English
DT Article
ID developmental switch; c-elegans; nematode; genes; lineages; expression; mutants
AB IN certain multicellular organisms, genetic regulatory systems that specify the timing of cell division, differentiation and morphogenesis 1-3 must accommodate environmental and physiological contingencies that perturb or arrest development.  For example, Caenorhabditis elegans can either develop continuously through four larval stages (L1-14) or arrest indefinitely as a 'dauer larva' at the second larval (L2) moult, and later resume L3 and L4 development 4-7.  At the larva-to-adult (L4) moult of both continuous and 'post-dauer' development, hypodermal cells switch (the 'L/A switch') from a proliferating state to the terminally differentiated state.  Four temporal regulators, lin-4, lin-14, lin-28 and lin-29, have been identified in C. elegans by mutations that cause precocious or retarded expression of stage-specific post-embryonic development events, including the L/A switch (refs 3, 8, 9; Fig. 1a).  These genes have been organized into a genetic pathway that controls the timing of the L/A switch during continuous development 10:  lin-29 activates the switch and the other heterochronic genes regulate it indirectly by regulating lin-29.  We have now examined how the proper timing of this event is specified in alternative developmental pathways.  In continuously developing lin-4, lin-14 and lin-28 mutants the L/A switch occurs at abnormally early or late moults 3,8, but during post-dauer development of the same mutants the L/A switch occurs normally.  Thus hypodermal cell differentiation is regulated by separate temporal control systems, depending on the developmental history.
RP LIU, ZC (corresponding author), HARVARD UNIV,DEPT CELLULAR & DEV BIOL,16 DIVIN AVE,CAMBRIDGE,MA 02138, USA.
NR 20
TC 51
Z9 61
U1 1
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 162
EP 165
DI 10.1038/350162a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500062
PM 26502479
DA 2026-03-10
ER

PT J
AU DODORICO, S
   OOSTERLOO, T
   ZWITTER, T
   CALVANI, M
AF DODORICO, S
   OOSTERLOO, T
   ZWITTER, T
   CALVANI, M
TI EVIDENCE THAT THE COMPACT OBJECT IN SS433 IS A NEUTRON-STAR AND NOT A BLACK-HOLE
SO NATURE
LA English
DT Article
ID x-ray; ss-433; candidate; spectrum; emission; eclipse; system; model
AB THE unusual galactic object SS433 is well known because of the periodic red and blueshifts, corresponding to velocities of 50,000 kms-1, of some of its emission lines 1,2. It is now believed to be a binary system that emits two oppositely directed precessing jets moving with a speed of 0.26c. The jets are produced and controlled by an accretion disk, probably geometrically thick, around a compact object whose nature is still controversial. Several arguments have been advanced 21-23 suggesting that it is a black hole. Here we report spectroscopic observations of the He II line at 4,686 angstrom from which we deduce a new estimate of the orbital speed of the compact object. Together with the mass ratio of the binary components, derived from X-ray observations, we find that the compact object is a neutron star, not a black hole. Analysis of the double-peaked profile of the He II line suggests that it is emitted by the accretion disk (or its corona), which is partly obscured by an opaque wind from the hot-spot region.
C1 EDVARD KARDELJ UNIV, DEPT PHYS, YU-61000 LJUBLJANA, YUGOSLAVIA.
   ASTRON OBSERV, I-35122 PADUA, ITALY.
C3 University of Ljubljana; University of Padua
RP DODORICO, S (corresponding author), EUROPEAN SO OBSERV, W-8046 GARCHING, GERMANY.
NR 24
TC 47
Z9 48
U1 0
U2 0
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 329
EP 331
DI 10.1038/353329a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400050
DA 2026-03-10
ER

PT J
AU BELGUED, M
   PAREJA, P
   AMARIGLIO, A
   AMARIGLIO, H
AF BELGUED, M
   PAREJA, P
   AMARIGLIO, A
   AMARIGLIO, H
TI CONVERSION OF METHANE INTO HIGHER HYDROCARBONS ON PLATINUM
SO NATURE
LA English
DT Article
ID catalysts; decomposition; oxidation
AB CONSIDERABLE effort has been devoted to the conversion of methane into more useful compounds 1.  Oxygen has generally been used to draw methane into reaction, at the cost of losing some of the feedstock as carbon dioxide.  Several catalytic routes exist for the formation of synthesis gas, (CO + H-2) 2,3, but attempts to synthesize higher hydrocarbons from methane have not yet resulted in a commercially viable process 4.  Here we report that exposure of platinum to pure methane, followed by hydrogenation, can result in appreciable conversion to aliphatic hydrocarbons with up to six carbon atoms.  Optimization of this process could lead to a new route to industrially important alkanes.
C1 CNRS,LAB MAURICE LETORT,F-54600 VILLERS LES NANCY,FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS)
RP BELGUED, M (corresponding author), UNIV NANCY 1,CATALYSE HETEROGENE LAB,BP 239,F-54506 VANDOEUVRE NANCY,FRANCE.
NR 12
TC 195
Z9 208
U1 2
U2 69
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 789
EP 790
DI 10.1038/352789a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400054
DA 2026-03-10
ER

PT J
AU BOWEN, BW
   MEYLAN, AB
   AVISE, JC
AF BOWEN, BW
   MEYLAN, AB
   AVISE, JC
TI EVOLUTIONARY DISTINCTIVENESS OF THE ENDANGERED KEMPS RIDLEY SEA-TURTLE
SO NATURE
LA English
DT Article
ID restriction endonucleases; mitochondrial-dna
AB THE endangered Kemp's ridley sea turtle (Lepidochelys kempi) nests almost exclusively at a single locality in the western Gulf of Mexico, whereas the olive ridley (L. olivacea) nests globally in warm oceans. Morphological similarities between kempi and olivacea, and a geographical distribution that ". . . makes no sense at all under modern conditions of climate and geography" 1, raise questions about the degree of evolutionary divergence between these taxa. Analysis of mitochondrial (mt) DNA restriction sites shows that Kemp's ridley is distinct from the olive ridley in matriarchal phylogeny, and that the two are sister taxa with respect to other marine turtles. Separation of olive and the Kemp's ridley lineages may date to formation of the Isthmus of Panama, whereas the global spread of the olive ridley lineage occurred recently. In contrast to recent examples in which molecular genetic assessments challenged systematic assignments underlying conservation programmes 2-6, our mtDNA data corroborate the taxonomy of an endangered form.
C1 UNIV GEORGIA,DEPT GENET,ATHENS,GA 30602.
   FLORIDA MARINE RES INST,ST PETERSBURG,FL 33701.
C3 University System of Georgia; University of Georgia
NR 29
TC 58
Z9 70
U1 0
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 709
EP 711
DI 10.1038/352709a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400056
PM 1876185
DA 2026-03-10
ER

PT J
AU PODSIADLOWSKI, P
   PRINGLE, JE
   REES, MJ
AF PODSIADLOWSKI, P
   PRINGLE, JE
   REES, MJ
TI THE ORIGIN OF THE PLANET ORBITING PSR1829-10
SO NATURE
LA English
DT Article
ID neutron star; binary; dwarf
AB BAILES et al. 1 have reported the discovery of a planet-mass object in a six-month orbit around the radio pulsar PSR1829-10.  The parameters of the orbit, in particular its circularity, make it unlikely that this planet existed before the supernova explosion that presumably created the pulsar, and somehow survived 1.  Here we present two alternative explanations for the existence and orbital parameters of the claimed planet-mass object. In the first, the pulsar forms from the coalescence of two white dwarfs, and the planet condenses from a massive disk of material left behind.  In the second, a neutron star collides with and cannibalizes the central star of a solar-type planetary system.  The orbits of the inner planets are made elliptical by this collision, but then recircularized by drag forces due to the extended but short-lived envelope of the disrupted central star.
RP PODSIADLOWSKI, P (corresponding author), UNIV CAMBRIDGE,INST ASTRON,MADINGLEY RD,CAMBRIDGE CB3 0HA,ENGLAND.
NR 13
TC 35
Z9 36
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 783
EP 784
DI 10.1038/352783a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400051
DA 2026-03-10
ER

PT J
AU ALDRICH, CJ
   HAMMER, RE
   JONESYOUNGBLOOD, S
   KOSZINOWSKI, U
   HOOD, L
   STROYNOWSKI, I
   FORMAN, J
AF ALDRICH, CJ
   HAMMER, RE
   JONESYOUNGBLOOD, S
   KOSZINOWSKI, U
   HOOD, L
   STROYNOWSKI, I
   FORMAN, J
TI NEGATIVE AND POSITIVE SELECTION OF ANTIGEN-SPECIFIC CYTOTOXIC LYMPHOCYTES-T AFFECTED BY THE ALPHA-3 DOMAIN OF MHC-I MOLECULES
SO NATURE
LA English
DT Article
ID histocompatibility complex antigens; cells; cd8; expression; hla-a2
AB THE alpha-1 and alpha-2 domains of major histocompatibility complex (MHC) class I molecules function in the binding and presentation of foreign peptides to the T-cell antigen receptor and control both negative and positive selection of the T-cell repertoire 1-3.  Although the alpha-3 domain of class I is not involved in peptide binding, it does interact with the T-cell accessory molecule, CD8 (refs 4, 5). CD8 is important in the selection of T cells as anti-CD8 antibody injected into perinatal mice interferes with this process 6.  We previously used a hybrid class I molecule with the alpha-1/alpha-2 domains from L(d) and the alpha-3 domain from Q7b and showed that this molecule binds an L(d)-restricted peptide but does not interact with CD8-dependent cytotoxic T lymphocytes 7.  Expression of this molecule in transgenic mice fails to negatively select a subpopulation of anti-L(d) cytotoxic T lymphocytes. In addition, positive selection of virus-specific L(d)-restricted cytotoxic T lymphocytes does not occur. We conclude that besides the alpha-1/alpha-2 domains of class I, the alpha-3 domain plays an important part in both positive and negative selection of antigen-specific cells.
C1 UNIV TEXAS,SW MED CTR,DEPT BIOCHEM,DALLAS,TX 75235.
   HOWARD HUGHES MED INST,DALLAS,TX 75235.
   UNIV ULM,VIROL ABT,W-7900 ULM,GERMANY.
   CALTECH,DEPT BIOL,PASADENA,CA 91125.
C3 University of Texas System; University of Texas Southwestern Medical Center; University of Texas Dallas; Howard Hughes Medical Institute; Ulm University; California Institute of Technology
RP ALDRICH, CJ (corresponding author), UNIV TEXAS,SW MED CTR,DEPT MICROBIOL,DALLAS,TX 75235, USA.
NR 24
TC 84
Z9 85
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 718
EP 721
DI 10.1038/352718a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400059
PM 1652099
DA 2026-03-10
ER

PT J
AU GILBERT, AD
AF GILBERT, AD
TI FAST DYNAMO ACTION IN A STEADY CHAOTIC FLOW
SO NATURE
LA English
DT Article
ID fast magnetic dynamos; streamlines
AB THE observation of rapid variations in the Sun's magnetic field motivates the search for 'fast dynamos' 1-3 - flows of highly conducting fluid that amplify magnetic fields on the typically rapid timescales of convection, rather than the longer timescales of diffusion.  Certain helical flows 4-6 have been proposed as possible fast dynamos, but numerical studies 7,8 of such flows have shown no conclusive evidence for this.  Here I examine the evolution of a magnetic field in one such flow, which possesses a web of chaotic streamlines mingled with tubes of regular streamlines 9.  In the case of no magnetic diffusion, I observe intense stretching and folding of the magnetic field in the chaotic regions of the flow.  The folding brings together field that is largely aligned in the same direction, and the average field in a chaotic region therefore grows exponentially with time.  This provides evidence for fast dynamo action, the main effect of weak diffusion being to average the field locally 10-13, and indicates that smooth, steady chaotic flows can be fast dynamos.
RP GILBERT, AD (corresponding author), UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,SILVER ST,CAMBRIDGE CB3 9EW,ENGLAND.
NR 24
TC 21
Z9 22
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 483
EP 485
DI 10.1038/350483a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300044
DA 2026-03-10
ER

PT J
AU ROUSSEL, MF
   CLEVELAND, JL
   SHURTLEFF, SA
   SHERR, CJ
AF ROUSSEL, MF
   CLEVELAND, JL
   SHURTLEFF, SA
   SHERR, CJ
TI MYC RESCUE OF A MUTANT CSF-1 RECEPTOR IMPAIRED IN MITOGENIC SIGNALING
SO NATURE
LA English
DT Article
ID recombinant murine retrovirus; factor-i receptor; nih 3t3 cells; c-myc; growth-factor; bone-marrow; transcription; kinase; fos; macrophages
AB THE colony-stimulating factor-1 receptor (CSF-1R) mediates its pleiotropic effects through the coupling of its ligand-activated tyrosine kinase to multiple intracellular effector proteins, whose combined actions determine the magnitude and specificity of the biological response. The interaction of cytoplasmic signalling molecules with CSF-1R is mediated in part by sequence motifs flanking sites of receptor tyrosine phosphorylation 1. Mutation of an autophosphorylation site at tyrosine 809 in the cytoplasmic domain of human CSF-1R does not significantly reduce its ligand-stimulated tyrosine kinase activity, binding to phosphatidylinositol 3-kinase, or induction of the immediate early response genes, c-fos and junB (ref. 2). Unlike cells bearing wild-type receptors, mouse NIH3T3 cells expressing mutant CSF-1R(Phe 809) were unable to grow in serum-free medium containing human recombinant CSF-1 and did not form colonies in semi-solid medium in its presence. CSF-1 induction of c-myc messenger RNA in these cells was impaired, but enforced expression of an exogenous c-myc gene restored their ability to proliferate in response to the growth factor. These studies demonstrate a receptor-mediated bifurcation of intracellular signal transduction pathways during the immediate early response and assign a central role for c-myc in CSF-1-induced mitogenesis.
C1 ST JUDE CHILDRENS RES HOSP, DEPT TUMOR CELL BIOL, 332 N LAUDERDALE, MEMPHIS, TN 38105 USA.
   ST JUDE CHILDRENS RES HOSP, DEPT BIOCHEM, MEMPHIS, TN 38105 USA.
   ST JUDE CHILDRENS RES HOSP, HOWARD HUGHES MED INST, MEMPHIS, TN 38105 USA.
   UNIV TENNESSEE, CTR HLTH SCI, COLL MED, DEPT BIOCHEM, MEMPHIS, TN 38163 USA.
C3 St Jude Children's Research Hospital; St Jude Children's Research Hospital; Howard Hughes Medical Institute; St Jude Children's Research Hospital; University of Tennessee System; University of Tennessee Health Science Center
NR 24
TC 170
Z9 183
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 361
EP 363
DI 10.1038/353361a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400064
PM 1833648
DA 2026-03-10
ER

PT J
AU ROY, AL
   MEISTERERNST, M
   POGNONEC, P
   ROEDER, RG
AF ROY, AL
   MEISTERERNST, M
   POGNONEC, P
   ROEDER, RG
TI COOPERATIVE INTERACTION OF AN INITIATOR-BINDING TRANSCRIPTION INITIATION-FACTOR AND THE HELIX LOOP HELIX ACTIVATOR USF
SO NATURE
LA English
DT Article
ID rna polymerase-ii; major late promoter; genetic specificity; upstream element; dna-binding; tata; proteins; identification; purification; expression
AB TRANSCRIPTION initiation by mammalian RNA polymerase II is effected by multiple common factors 1,2 interacting through minimal promoter elements and regulated by gene-specific factors 3 interacting with distal control elements. Minimal promoter elements that can function independently or together, depending on the specific promoter, include the upstream TATA box 4,5 and a pyrimidine-rich initiator 6-8 (Inr) overlapping the transcription start site. The binding of TFIID to the TATA element 4,9 promotes the assembly of other factors into a preinitiation complex 10-12 but factors which function at the Inr have not been defined. We show here that a novel factor (TFII-I) binds specifically to Inr elements, supports basal transcription from the adenovirus major late promoter and is immunologically related to the helix-loop-helix activator USF (ref. 13). We further show that TFII-I also binds to the upstream high-affinity USF site (E box), that USF also binds to the Inr, and that TFII-I and USF interact cooperatively at both Inr and E box sites. Thus, TFII-I represents a novel type of transcription initiation factor whose interactions at multiple promoter elements may aid novel communication mechanisms between upstream regulatory factors and the general transcriptional machinery.
RP ROY, AL (corresponding author), ROCKEFELLER UNIV,BIOCHEM & MOLEC BIOL LAB,NEW YORK,NY 10021, USA.
NR 24
TC 445
Z9 479
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 245
EP 248
DI 10.1038/354245a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800054
PM 1961251
DA 2026-03-10
ER

PT J
AU RAHA, N
   SELLWOOD, JA
   JAMES, RA
   KAHN, FD
AF RAHA, N
   SELLWOOD, JA
   JAMES, RA
   KAHN, FD
TI A DYNAMIC INSTABILITY OF BARS IN DISK GALAXIES
SO NATURE
LA English
DT Article
ID galactic bulges; box
AB STRONG, rapidly rotating, persistent bars readily form in numerical simulations of initially axisymmetric disk galaxies 1-4.  The global dynamical instability responsible for this behaviour is a great embarrassment to the subject of galactic dynamics, as most galaxies in the sky do not possess a strong bar 5; the suggestion 3 that the dark matter content or galaxies might resolve this discrepancy is unattractive 6.  Here we present the results of three-dimensional simulations which show that the bar is dynamically unstable to buckling out of the galactic plane (the majority of previous disk galaxy simulations have been strictly two-dimensional). Stars acquire large motions normal to the plane, giving the bar a peanut shape through a mechanism that we suggest to be the fire-hose instability 7-9.  Bars may be weakened or even destroyed by this instability; thus the fraction of disk galaxies containing strong bars today could be lower than the fraction in which they have formed in the past. The instability may also account for the peanut morphology of many galaxies, and because it leads to a less flattened stellar system with increased central density, it may play a part in the formation of galactic bulges.
RP RAHA, N (corresponding author), UNIV MANCHESTER,DEPT ASTRON,MANCHESTER M13 9PL,LANCS,ENGLAND.
NR 18
TC 452
Z9 469
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 411
EP 412
DI 10.1038/352411a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600056
DA 2026-03-10
ER

PT J
AU GREEN, WV
   ACHAUER, U
   MEYER, RP
AF GREEN, WV
   ACHAUER, U
   MEYER, RP
TI A 3-DIMENSIONAL SEISMIC IMAGE OF THE CRUST AND UPPER MANTLE BENEATH THE KENYA RIFT
SO NATURE
LA English
DT Article
ID east-african rift; gregory rift; lithosphere; valley; volcanism; velocity; gravity; magma
AB A tomographic image of the seismic structure beneath the Kenya rift shows its three-dimensional character. in the lower crust, an axial zone of high seismic velocity varies in width and magnitude along the axis, suggesting that the amount of crustal modification also varies along the length of the rift. In the upper mantle, a steep-sided low-velocity body indicates the presence of partial melt, and its shape suggests that diapirs rise from a narrow wedge of asthenosphere beneath the rift axis in response to extension by pure shear.
C1 UNIV KARLSRUHE,INST GEOPHYS,W-7500 KARLSRUHE,GERMANY.
C3 Helmholtz Association; Karlsruhe Institute of Technology
RP GREEN, WV (corresponding author), UNIV WISCONSIN,DEPT GEOL & GEOPHYS,MADISON,WI 53706, USA.
NR 34
TC 108
Z9 113
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 199
EP 203
DI 10.1038/354199a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800039
DA 2026-03-10
ER

PT J
AU PAPAZIAN, DM
   TIMPE, LC
   JAN, YN
   JAN, LY
AF PAPAZIAN, DM
   TIMPE, LC
   JAN, YN
   JAN, LY
TI ALTERATION OF VOLTAGE-DEPENDENCE OF SHAKER POTASSIUM CHANNEL BY MUTATIONS IN THE S4-SEQUENCE
SO NATURE
LA English
DT Article
ID sodium-channel; xenopus oocytes; electrophorus-electricus; complementary-dna; drosophila muscle; gating currents; molecular-model; na channels; inactivation; locus
AB Voltage-dependent potassium, sodium and calcium ion channels may share a common mechanism of activation, in which the conserved S4 sequence acts as the primary voltage sensor.  Site-directed mutagenesis of the S4 sequence of the Shaker potassium channel and electrophysiological analysis suggest that voltage-dependent activation involves the S4 sequence but is not solely due to electrostatic interactions.
C1 UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143.
   UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM,SAN FRANCISCO,CA 94143.
   UNIV CALIF SAN FRANCISCO,HOWARD HUGHES MED INST,SAN FRANCISCO,CA 94143.
C3 University of California System; University of California San Francisco; University of California System; University of California San Francisco; Howard Hughes Medical Institute; University of California System; University of California San Francisco
FU NIGMS NIH HHS [R01 GM043459] Funding Source: Medline
NR 41
TC 456
Z9 535
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 305
EP 310
DI 10.1038/349305a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100043
PM 1846229
DA 2026-03-10
ER

PT J
AU LAINE, RM
   BLOHOWIAK, KY
   ROBINSON, TR
   HOPPE, ML
   NARDI, P
   KAMPF, J
   UHM, J
AF LAINE, RM
   BLOHOWIAK, KY
   ROBINSON, TR
   HOPPE, ML
   NARDI, P
   KAMPF, J
   UHM, J
TI SYNTHESIS OF PENTACOORDINATE SILICON COMPLEXES FROM SIO2
SO NATURE
LA English
DT Article
ID polymer electrolyte; nucleophiles; reactivity; si-29; nmr
AB THE potential role of inorganic and organometallic silicon compounds in the development of new chemical reagents, polymers, glasses and ceramics 1 is limited at present by the paucity of simple silicon-containing starting materials. Whereas industrial carbon-based chemistry can draw on the diversity of compounds produced from crude oil, coal or other natural sources, silicon chemistry 2 relies almost exclusively on the carbothermal reduction of SiO2 to silicon. This is then transformed into feedstock chemicals by reaction with HCl, or by routes such as the 'direct process' for making methylchlorosilanes 2, in which silicon is reacted with methyl chloride at 200-350-degrees-C over a copper/tin catalyst. Organosilicon compounds are in demand in fields ranging from organic synthesis to ceramics to the electronics industry. New synthetic routes to these materials are therefore highly desirable, especially if they rely on low-cost SiO2 and on processing methods that avoid the energy-intensive and equipment-intensive carbothermal reduction step which currently precedes almost all silicon chemistry. Here we describe a direct process in which SiO2 is reacted with ethylene glycol and an alkali base to produce highly reactive, pentacoordinate silicates which provide access to a wide variety of new silicon compounds.
C1 UNIV MICHIGAN,DEPT MAT SCI & ENGN,ANN ARBOR,MI 48109.
   UNIV MICHIGAN,DEPT CHEM,ANN ARBOR,MI 48109.
C3 University of Michigan System; University of Michigan; University of Michigan System; University of Michigan
RP LAINE, RM (corresponding author), UNIV WASHINGTON,DEPT MAT SCI & ENGN,SEATTLE,WA 98195, USA.
NR 19
TC 144
Z9 173
U1 3
U2 82
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 642
EP 644
DI 10.1038/353642a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200063
DA 2026-03-10
ER

PT J
AU MOSIER, A
   SCHIMEL, D
   VALENTINE, D
   BRONSON, K
   PARTON, W
AF MOSIER, A
   SCHIMEL, D
   VALENTINE, D
   BRONSON, K
   PARTON, W
TI METHANE AND NITROUS-OXIDE FLUXES IN NATIVE, FERTILIZED AND CULTIVATED GRASSLANDS
SO NATURE
LA English
DT Article
ID shortgrass steppe; forest soils; emissions; field
AB METHANE and nitrous oxide are long-lived, radiatively active trace gases that account for approximately 20% of the total anticipated atmospheric warming 1. The atmospheric concentrations of both gases have increased dramatically over the past few decades, and continue to increase at a rate of approximately 1.1 and 0.25% yr-1 for CH4 (ref. 2) and N2O (ref. 3) respectively. Increased biospheric production is generally suggested as the reason for the increases, but decreases in global sinks may also be important. It has been suggested, for example, that nitrogen fertilization may decrease the rate at which tropical 4,5 and temperate forest soils 6 take up methane from the atmosphere. Furthermore, the recent extensive changes in land management and cultivation could be contributing to the observed increases in both atmospheric CH4 and N2O, as has been suggested for tropical soils 7. Little information exists on CH4 uptake in temperate grasslands (which currently occupy approximately 8% of the Earth's surface), its relation to N2O production, or the effect of land management or cultivation 8,9. Here we report measurements of CH4 uptake and N2O emissions in native, nitrogen-fertilized and wheat-growing prairie soils from spring to late autumn, 1990. We found that nitrogen fertilization and cultivation can both decrease CH4 uptake and increase N2O production, thereby contributing to the increasing atmospheric concentrations of these gases.
C1 COLORADO STATE UNIV, NAT RESOURCE ECOL LAB, FT COLLINS, CO 80523 USA.
C3 Colorado State University System; Colorado State University Fort Collins
RP MOSIER, A (corresponding author), USDA ARS, POB E, FT COLLINS, CO 80522 USA.
NR 20
TC 783
Z9 910
U1 1
U2 289
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 330
EP 332
DI 10.1038/350330a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800088
DA 2026-03-10
ER

PT J
AU DOLCI, S
   WILLIAMS, DE
   ERNST, MK
   RESNICK, JL
   BRANNAN, CI
   LOCK, LF
   LYMAN, SD
   BOSWELL, HS
   DONOVAN, PJ
AF DOLCI, S
   WILLIAMS, DE
   ERNST, MK
   RESNICK, JL
   BRANNAN, CI
   LOCK, LF
   LYMAN, SD
   BOSWELL, HS
   DONOVAN, PJ
TI REQUIREMENT FOR MAST-CELL GROWTH-FACTOR FOR PRIMORDIAL GERM-CELL SURVIVAL IN CULTURE
SO NATURE
LA English
DT Article
ID receptor tyrosine kinases; c-kit; si-locus; ligand; mouse; identification; progenitors; expression; cloning; rat
AB MAST-CELL growth factor (MGF) is encoded by the murine steel (Sl) locus and is a ligand for the tyrosine kinase receptor protein encoded by the proto-oncogene c-kit at the murine dominant white spotting (W) locus.  Mutations at both these loci affect mast cells, primordial germ cells (PGCs), haemopoietic stem cells and melanocytes.  In many Sl and W mutants, the rapid proliferation of PGC that normally occurs between day 7 and 13.5 of embryonic development fails to occur.  As c-kit is expressed in PGCs 1,2 while MGF is expressed in the surrounding mesenchyme 2,3, MGF might promote the proliferation of PGCs.  Here we report that MGF is essential for PGC survival in culture, but does not stimulate PGC proliferation.  Moreover, whereas both the transmembrane and soluble proteolytic cleavage forms of MGF stimulate mast-cell proliferation, soluble MGF has a relatively limited ability to support survival of PGCs in culture, thus explaining the sterility in mice carrying the steel-dickie (Sl(d)) mutation, which encodes only a soluble form of MGF, and providing a functional role for a transmembrane growth factor.
C1 NCI,FREDERICK CANC RES & DEV CTR,ABL BASIC RES PROGRAM,MAMMALIAN GENET LAB,FREDERICK,MD 21702.
   NCI,FREDERICK CANC RES & DEV CTR,ABL BASIC RES PROGRAM,MOLEC MECHANISMS CARCINOGENESIS LAB,FREDERICK,MD 21702.
   IMMUNEX CORP,DEPT EXPTL HEMATOL,SEATTLE,WA 98101.
   IMMUNEX CORP,DEPT MOLEC BIOL,SEATTLE,WA 98101.
   INDIANA UNIV,SCH MED,INDIANAPOLIS,IN 46202.
   UNIV ROME TOR VERGATA 2,DIPARTIMENTO SANITA PUBBL & BIOL CELLULARE,I-00173 ROME,ITALY.
C3 Science Applications International Corporation (SAIC); SAIC-Frederick; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Science Applications International Corporation (SAIC); SAIC-Frederick; Immunex Corporation; Immunex Corporation; Indiana University System; Indiana University Indianapolis; University of Rome Tor Vergata
NR 26
TC 447
Z9 474
U1 1
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 809
EP 811
DI 10.1038/352809a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400062
PM 1715518
DA 2026-03-10
ER

PT J
AU SUNDA, WG
   SWIFT, DG
   HUNTSMAN, SA
AF SUNDA, WG
   SWIFT, DG
   HUNTSMAN, SA
TI LOW IRON REQUIREMENT FOR GROWTH IN OCEANIC PHYTOPLANKTON
SO NATURE
LA English
DT Article
ID diatom thalassiosira-weissflogii; marine-phytoplankton; cellular manganese; zinc; estuarine; cadmium; copper
AB DESPITE the controversy on the importance of iron in limiting phytoplankton growth and affecting air-sea exchange of CO2 in the ocean 1-4, there is very little information on cellular iron requirements for growth.  The few data available 5,6 come from species isolated from coastal sea water where dissolved Fe levels are 10-1,000 times higher than those (less-than-or-equal-to 0.1 nM) in the open ocean 1,7.  Species from oceanic waters require much lower external Fe concentrations for growth than do comparable coastal species 8.  Here we report that an oceanic diatom was able to grow at a near maximum specific rate of about 1.0 per day at a cellular Fe:C ratio of 2-mu-mol:mol, about 25% of the amount needed for the same rate in a related estuarine species, and 2-20% of values previously used to estimate algal Fe requirements in sea water 1,2.  These results have important implications concerning iron limitation of primary productivity in the ocean and cell biology of iron in oceanic algae.
C1 NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,BEAUFORT LAB,BEAUFORT,NC 28516.
   UNIV RHODE ISL,GRAD SCH OCEANOG,NARRAGANSETT,RI 02882.
C3 National Oceanic Atmospheric Admin (NOAA) - USA; University of Rhode Island
NR 21
TC 249
Z9 274
U1 1
U2 72
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 55
EP 57
DI 10.1038/351055a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300057
DA 2026-03-10
ER

PT J
AU AHMEDZAID, I
   MADON, M
AF AHMEDZAID, I
   MADON, M
TI A HIGH-PRESSURE FORM OF AL2SIO5 AS A POSSIBLE HOST OF ALUMINUM IN THE LOWER MANTLE
SO NATURE
LA English
DT Article
ID diamond-anvil cell; natural olivine
AB ALTHOUGH iron, magnesium and calcium silicates are the principal components of the lower mantle, the significant amount of aluminium present must also be included in models of mantle geochemistry 1-4.  The host mineral for aluminium and other trivalent ions is still open to debate.  Candidates include a high-pressure form of MgAl2O4 (ref. 5), a form of (Ca,Mg)Al2Si2O8 with the hollandite structure 6 and Ca2AlSiO5.5 with a rhombohedral perovskite structure 7.  Here we describe a new candidate formed by transforming CaAl2Si2O8 anorthite, Ca3Al2Si3O12 grossular and Mg3Al2Si3O12 pyrope in a diamond anvil cell at 2,500 K and 40-70 GPa.  Analytical transmission electron microscopy reveals the formation of a new high-pressure phase of Al2SiO5, for which electron diffraction patterns show strong similarities to the V3O5 structure.  We estimate that this phase could be present in the lower mantle in a volumetric proportion of about 5%.
RP AHMEDZAID, I (corresponding author), INST PHYS GLOBE,DEPT GEOMAT,4 PL JUSSIEU,F-75252 PARIS 05,FRANCE.
NR 18
TC 31
Z9 33
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 426
EP 428
DI 10.1038/353426a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600055
DA 2026-03-10
ER

PT J
AU THELEN, M
   ROSEN, A
   NAIRN, AC
   ADEREM, A
AF THELEN, M
   ROSEN, A
   NAIRN, AC
   ADEREM, A
TI REGULATION BY PHOSPHORYLATION OF REVERSIBLE ASSOCIATION OF A MYRISTOYLATED PROTEIN-KINASE-C SUBSTRATE WITH THE PLASMA-MEMBRANE
SO NATURE
LA English
DT Article
ID phorbol esters; growth-factors; okadaic acid; activation; receptor; binding; brain
AB PROTEIN kinase C (PKC) transduces receptor-mediated signals by phosphorylating membrane-bound substrates which then act as effectors of specific cellular responses 1.  The myristoylated alanine-rich C kinase substrate (MARCKS) is a specific PKC substrate which has been implicated in macrophage activation, neurosecretion and growth factor-dependent mitogenesis 2-5.  Myristoylation of MARCKS is required for effective binding to the plasma membrane 6 where it colocalizes with PKC 7.  Here we report that PKC-dependent phosphorylation displaces MARCKS from the membrane and that its subsequent dephosphorylation is accompanied by its reassociation with the membrane.  This cycle of phosphorylation-dependent membrane attachment and detachment of a myristoylated protein represents a novel mechanism of reversible membrane targeting.  As MARCKS is a calmodulin- and actin-binding protein (ref. 8, and J. Hartwig et al., manuscript submitted), the cycle of membrane attachment/detachment represents a mechanism through which PKC might reversibly regulate actin-membrane interaction.
C1 ROCKEFELLER UNIV,1230 YORK AVE,NEW YORK,NY 10021.
C3 Rockefeller University
NR 17
TC 364
Z9 408
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 320
EP 322
DI 10.1038/351320a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600062
PM 2034276
DA 2026-03-10
ER

PT J
AU TRUMPER, J
   HASINGER, G
   ASCHENBACH, B
   BRAUNINGER, H
   BRIEL, UG
   BURKERT, W
   FINK, H
   PFEFFERMANN, E
   PIETSCH, W
   PREDEHL, P
   SCHMITT, JHMM
   VOGES, W
   ZIMMERMANN, U
   BEUERMANN, K
AF TRUMPER, J
   HASINGER, G
   ASCHENBACH, B
   BRAUNINGER, H
   BRIEL, UG
   BURKERT, W
   FINK, H
   PFEFFERMANN, E
   PIETSCH, W
   PREDEHL, P
   SCHMITT, JHMM
   VOGES, W
   ZIMMERMANN, U
   BEUERMANN, K
TI X-RAY SURVEY OF THE LARGE MAGELLANIC CLOUD BY ROSAT
SO NATURE
LA English
DT Article
ID supernova-1987a; catalog; discovery; emission; binary
AB The central region of the Large Magellanic Cloud (LMC) contains a variety of astrophysical objects including supernova remnants, X-ray binary systems, the 30 Doradus complex of hot stars, as well as supernova 1987A.  A survey in X-rays of this region, taken as the 'first light' observations with the Rontgen Observatory Satellite (ROSAT), reveals 45 individual sources.  Fifteen of these are new; the brightest is probably a new and strongly variable low-mass X-ray binary.
C1 TECH UNIV BERLIN,INST ASTRON & ASTROPHYS,W-1000 BERLIN,GERMANY.
C3 Technical University of Berlin
RP TRUMPER, J (corresponding author), MAX PLANCK INST EXTRATERRESTR PHYS,W-8046 GARCHING,GERMANY.
NR 33
TC 251
Z9 254
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 579
EP 583
DI 10.1038/349579a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000049
DA 2026-03-10
ER

PT J
AU CORDES, JM
   WEISBERG, JM
   FRAIL, DA
   SPANGLER, SR
   RYAN, M
AF CORDES, JM
   WEISBERG, JM
   FRAIL, DA
   SPANGLER, SR
   RYAN, M
TI THE GALACTIC DISTRIBUTION OF FREE-ELECTRONS
SO NATURE
LA English
DT Article
ID interstellar-medium; density turbulence; pulsars; scintillation; scattering; spectrum; plasma; scale
AB Dispersion, distance and scattering measurements of pulsars and other radio sources are now sufficiently numerous to allow modelling of the entire galactic distribution of free electrons. A two-component axisymmetric model of local electron density, fitted on all scales from 100 km to a few parsecs, accounts for most of the data; a population of dense, discrete clouds is also needed, and there is some evidence for spiral structure.
C1 CORNELL UNIV,NAIC,ITHACA,NY 14853.
   CARLETON COLL,DEPT PHYS & ASTRON,NORTHFIELD,MN 55057.
   NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801.
   CORNELL UNIV,DEPT PHYS,ITHACA,NY 14853.
   UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242.
C3 Cornell University; Carleton College; National Radio Astronomy Observatory (NRAO); Cornell University; University of Iowa
RP CORDES, JM (corresponding author), CORNELL UNIV,DEPT ASTRON,ITHACA,NY 14853, USA.
NR 33
TC 163
Z9 170
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 121
EP 124
DI 10.1038/354121a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000050
DA 2026-03-10
ER

PT J
AU HILGEMANN, DW
   NICOLL, DA
   PHILIPSON, KD
AF HILGEMANN, DW
   NICOLL, DA
   PHILIPSON, KD
TI CHARGE MOVEMENT DURING NA+ TRANSLOCATION BY NATIVE AND CLONED CARDIAC NA+/CA2+ EXCHANGER
SO NATURE
LA English
DT Article
ID sodium-calcium exchange; sarcolemmal membrane patches; current-voltage relationship; pig ventricular myocytes; ca exchange; guinea-pig; na/k pump; dependence; stoichiometry; transients
AB Na+/Ca2+ EXCHANGE is electrogenic and moves one net positive charge per cycle 1,2.  Although the cardiac exchanger has a three-to-one Na+/Ca2+ stoichiometry 3, details of the reaction cycle are not well defined 2,4-8.  Here we associate Na+ translocation by the cardiac exchanger with positive charge movement in giant membrane patches from cardiac myocytes 9,10 and oocytes expressing the cloned cardiac Na+/Ca2+ exchanger 11.  The charge movements are initiated by step increments of the cytoplasmic Na+ concentration in the absence of Ca2+. Giant patches from control oocytes lack both steady-state Na/Ca2+ exchange current (I(NaCa)) and Na+-induced charge movements. Charge movements indicate about 400 exchangers per mu-m2 in guinea-pig sarcolemma. Fully activated I(NaCa) densities (20-30-mu-A cm-2) indicate maximum turnover rates of 5,000 s-1. As has been predicted for consecutive exchange models 4-7, the apparent ion affinities of steady state I(NaCa) increase as the counterion concentrations are decreased. Consistent with an electroneutral Ca2+ translocation, we find that voltage dependence of I(NaCa) in both directions is lost as Ca2+ concentration is decreased. The principal electrogenic step seems to be at the extracellular end of the Na+ translocation pathway.
C1 UNIV CALIF LOS ANGELES,SCH MED,DEPT MED,LOS ANGELES,CA 90024.
   UNIV CALIF LOS ANGELES,SCH MED,DEPT PHYSIOL,LOS ANGELES,CA 90024.
   UNIV CALIF LOS ANGELES,SCH MED,CARDIOVASC RES LAB,LOS ANGELES,CA 90024.
C3 University of California System; University of California Los Angeles; University of California Los Angeles Medical Center; David Geffen School of Medicine at UCLA; University of California System; University of California Los Angeles; University of California Los Angeles Medical Center; David Geffen School of Medicine at UCLA; University of California System; University of California Los Angeles; University of California Los Angeles Medical Center; David Geffen School of Medicine at UCLA
RP HILGEMANN, DW (corresponding author), UNIV TEXAS,SW MED CTR,DEPT PHYSIOL,DALLAS,TX 75235, USA.
NR 24
TC 203
Z9 223
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 715
EP 718
DI 10.1038/352715a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400058
PM 1876186
DA 2026-03-10
ER

PT J
AU DYSON, PJ
   KNIGHT, AM
   FAIRCHILD, S
   SIMPSON, E
   TOMONARI, K
AF DYSON, PJ
   KNIGHT, AM
   FAIRCHILD, S
   SIMPSON, E
   TOMONARI, K
TI GENES ENCODING LIGANDS FOR DELETION OF V-BETA-11 T-CELLS COSEGREGATE WITH MAMMARY-TUMOR VIRUS GENOMES
SO NATURE
LA English
DT Article
ID major histocompatibility complex; clonal deletion; enterotoxin-b; tolerance; products; reactivity; antigens; markers; mls
AB THE T-cell receptor (TCR) repertoire is selected in the thymus after rearrangement of genes encoding TCR alpha and beta chains 1.  Selection is based on the recognition by newly emergent T cells of self-ligands associated with molecules of the major histocompatibility complex:  some combinations result in positive selection, others in negative selection. Negative selection, or clonal deletion, is an important mechanism for eliminating autoreactive T cells.  A group of self-ligands involved in clonal deletion was identified because they, like exogenous superantigens 2, were recognized by almost all T cells expressing particular TCR V-beta genes.  V-beta-17a T cells are deleted by a tissue-specific ligand 3,4; V-beta-6, V-beta-7, V-beta-8.1 and V-beta-9 T cells are deleted by the minor lymphocyte-stimulating (Mls) determinant Mls-1a (refs 5-8); V-beta-3 T cells by Mls-2a and Mls-3a (refs 9,10); V-beta-11 T cells 11 by ligands encoded by independently segregating genes; and V-beta-5 T cells by ligands encoded by two genes 12. Chromosomes mapping using recombinant inbred strains of mice and classic backcrosses show that Mls-1a in DBA/2 mice is encoded on chromosome 1, that one of the two ligand genes for deletion of V-beta-5 T cells maps to chromosome 12 (ref. 12) and that a ligand gene for V-beta-11 deletion is linked to the CD8 locus on chromosome 6 (ref. 11). Here we present evidence from three sets of backcross mice for concordance between V-beta-11 deletion ligand genes on chromosomes 6, 12 and 14 and endogenous mouse mammary tumour virus integrant (Mtv) genomes.  Our results indicate that the V-beta-11 deletion ligands are products of Mtv genomes.
RP DYSON, PJ (corresponding author), CLIN RES CTR,WATFORD RD,HARROW HA1 3UJ,MIDDX,ENGLAND.
NR 32
TC 332
Z9 337
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 531
EP 532
DI 10.1038/349531a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100069
PM 1846950
DA 2026-03-10
ER

PT J
AU DSOUZA, SE
   GINSBERG, MH
   MATSUEDA, GR
   PLOW, EF
AF DSOUZA, SE
   GINSBERG, MH
   MATSUEDA, GR
   PLOW, EF
TI A DISCRETE SEQUENCE IN A PLATELET INTEGRIN IS INVOLVED IN LIGAND RECOGNITION
SO NATURE
LA English
DT Article
ID iib-iiia complex; membrane glycoprotein-iib; cell-binding domain; fibrinogen binding; gamma-chain; synthetic peptides; alpha-subunits; acid sequences; fibronectin; receptor
AB PLATELET membrane glycoprotein IIb-IIIa (gpIIb-IIIa; alpha-IIb-beta-3), the most prominent member of the integrin family of adhesion receptors on these cells, mediates platelet aggregation by binding fibrinogen and is critical in thrombosis and haemostasis 1-5. A short amino-acid sequence at the carboxy terminus of the gamma-chain of fibrinogen is recognized by gpIIb-IIIa (ref. 6) and peptides containing this sequence are selectively crosslinked to residues 294-314 of gpIIb (ref. 7). Here we show that an 11-residue peptide from this region of gpIIb inhibits platelet aggregation and binding of fibrinogen to platelets and to purified gpIIb-IIIa, and that it interacts directly with fibrinogen. These results implicate this segment of gpIIb-IIIa in the ligand-binding function of the receptor. Moreover, as this region is highly conserved among integrins, it may have a general function in ligand recognition by this broadly distributed family of adhesion receptors.
C1 PRINCETON UNIV, SQUIBB LABS BIOL, PRINCETON, NJ 08544 USA.
C3 Princeton University
RP DSOUZA, SE (corresponding author), SCRIPPS RES INST, COMM VASC BIOL, 10666 N TORREY PINES RD, LA JOLLA, CA 92037 USA.
NR 29
TC 200
Z9 209
U1 0
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 66
EP 68
DI 10.1038/350066a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300066
PM 2002847
DA 2026-03-10
ER

PT J
AU CHARTIERHARLIN, MC
   CRAWFORD, F
   HOULDEN, H
   WARREN, A
   HUGHES, D
   FIDANI, L
   GOATE, A
   ROSSOR, M
   ROQUES, P
   HARDY, J
   MULLAN, M
AF CHARTIERHARLIN, MC
   CRAWFORD, F
   HOULDEN, H
   WARREN, A
   HUGHES, D
   FIDANI, L
   GOATE, A
   ROSSOR, M
   ROQUES, P
   HARDY, J
   MULLAN, M
TI EARLY-ONSET ALZHEIMERS-DISEASE CAUSED BY MUTATIONS AT CODON-717 OF THE BETA-AMYLOID PRECURSOR PROTEIN GENE
SO NATURE
LA English
DT Article
ID polymorphisms
AB A MUTATION at codon 717 of the beta-amyloid precursor protein gene has been found to cosegregate with familial Alzheimer's disease in a single family 1. This mutation has been reported in a further five out of approximately 100 families multiply affected by Alzheimer's disease 1-4. We have identified another family, F19, in which we have detected linkage between the beta-amyloid precursor protein gene and Alzheimer's disease. Direct sequencing of exon 17 (ref. 5) in affected individuals from this family has revealed a base change producing a Val --> Gly substitution, also at codon 717. The occurrence of a second allelic variant at codon 717 linked to the Alzheimer's phenotype supports the hypothesis that they are pathogenic mutations.
C1 UNIV LONDON IMPERIAL COLL SCI & TECHNOL, ST MARYS HOSP, SCH MED, DEPT BIOCHEM, LONDON W2 1PG, ENGLAND.
   UNIV LONDON IMPERIAL COLL SCI & TECHNOL, ST MARYS HOSP, SCH MED, DEPT NEUROL, LONDON W2 1PG, ENGLAND.
   JOHNS HOPKINS UNIV, SCH MED, DEPT PSYCHIAT, BALTIMORE, MD 21205 USA.
   JOHNS HOPKINS UNIV, SCH MED, DEPT BEHAV SCI, BALTIMORE, MD 21205 USA.
C3 Imperial College London; Imperial College London; Johns Hopkins University; Johns Hopkins University
FU Wellcome Trust Funding Source: Medline
NR 20
TC 1114
Z9 1422
U1 0
U2 54
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 844
EP 846
DI 10.1038/353844a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200059
PM 1944558
DA 2026-03-10
ER

PT J
AU SANDLER, DG
   BARRETT, TK
   PALMER, DA
   FUGATE, RQ
   WILD, WJ
AF SANDLER, DG
   BARRETT, TK
   PALMER, DA
   FUGATE, RQ
   WILD, WJ
TI USE OF A NEURAL NETWORK TO CONTROL AN ADAPTIVE OPTICS SYSTEM FOR AN ASTRONOMICAL TELESCOPE
SO NATURE
LA English
DT Article
AB ANGEL et al. 1 recently showed how an artificial neural network could be used to measure optical phase distortion induced by atmospheric turbulence, and demonstrated by numerical simulation that such a system could be used to control the six 1.8-m mirrors of the Multiple Mirror Telescope by constantly adjusting them to compensate for atmospheric distortion of the image.  The neural network estimates the phase distortion using two images of a reference star, or of a laser-produced guide star 2, one image being at the best focus of the telescope while the other is intentionally out of focus.  Here we report the successful test of a neural network with a real star.  We applied a neural network to in- and out-of-focus images of Vega obtained with the 1.5-m single-mirror telescope at the Starfire Optical Range of the Air Force Phillips Laboratory near Albuquerque, New Mexico.  The experimental results agree well with phase reconstructions obtained simultaneously with a conventional wave-front sensor.
C1 USAF,PHILLIPS LAB,STARFIRE OPT RANGE,ALBUQUERQUE,NM 87117.
C3 United States Department of Defense; United States Air Force
RP SANDLER, DG (corresponding author), THERMO ELECTRON TECHNOL,9550 DISTRIBUT AVE,SAN DIEGO,CA 92121, USA.
NR 13
TC 79
Z9 91
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 300
EP 302
DI 10.1038/351300a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600053
DA 2026-03-10
ER

PT J
AU GOODALE, MA
   MILNER, AD
   JAKOBSON, LS
   CAREY, DP
AF GOODALE, MA
   MILNER, AD
   JAKOBSON, LS
   CAREY, DP
TI A NEUROLOGICAL DISSOCIATION BETWEEN PERCEIVING OBJECTS AND GRASPING THEM
SO NATURE
LA English
DT Article
AB Studies of the visual capacity of neurological patients have provided evidence for a dissociation between the perceptual report of a visual stimulus and the ability to direct spatially accurate movements toward that stimulus.  Some patients with damage to the parietal lobe, for example, are unable to reach accurately towards visual targets that they unequivocally report seeing 1,2.  Conversely, some patients with extensive damage to primary visual cortex can make accurate pointing movements or saccades toward a stimulus presented in their 'blind' scotoma 3-5.  But in investigations of visuomotor control in patients with visual disorders, little consideration has ben given to complex acts such as manual prehension.  Grasping a three-dimensional object requires knowledge not only of the object's spatial location, but also of its form, orientation and size.  We have examined a patient with a profound disorder in the perception of such object qualities.  Our quantitative analyses demonstrate strikingly accurate guidance of hand and finger movements directed at the very objects whose qualities she fails to perceive.  These data suggest that the neural substrates for the visual perception of object qualities such as shape, orientation and size are distinct from those underlying the use of those qualities in the control of manual skills.
C1 UNIV ST ANDREWS,PSYCHOL LAB,ST ANDREWS KY16 9JU,FIFE,SCOTLAND.
   UNIV WESTERN ONTARIO,DEPT PSYCHOL,LONDON N6A 5C2,ONTARIO,CANADA.
C3 University of St Andrews; Western University (University of Western Ontario)
NR 12
TC 976
Z9 1117
U1 1
U2 101
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 154
EP 156
DI 10.1038/349154a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800057
PM 1986306
DA 2026-03-10
ER

PT J
AU BIRD, GS
   ROSSIER, MF
   HUGHES, AR
   SHEARS, SB
   ARMSTRONG, DL
   PUTNEY, JW
AF BIRD, GS
   ROSSIER, MF
   HUGHES, AR
   SHEARS, SB
   ARMSTRONG, DL
   PUTNEY, JW
TI ACTIVATION OF CA2+ ENTRY INTO ACINAR-CELLS BY A NON-PHOSPHORYLATABLE INOSITOL TRISPHOSPHATE
SO NATURE
LA English
DT Article
ID rat-liver cells; 1,4,5-trisphosphate 3-kinase; intracellular ca-2+; calcium release; 1,3,4,5-tetrakisphosphate; phosphates; receptor; membrane; thapsigargin; purification
AB IN many cell types, receptor activation of phosphoinositidase C results in an initial release of intracellular Ca2+ stores followed by sustained Ca2+ entry across the plasma membrane. Inositol 1,4,5-trisphosphate is the mediator of the initial Ca2+ release 1, although its role in the mechanism underlying Ca2+ entry remains controversial 2-6. We have now used two techniques to introduce inositol phosphates into mouse lacrimal acinar cells and measure their effects on Ca2+ entry: microinjection into cells loaded with Fura-2, a fluorescent dye which allows the measurement of intracellular free calcium concentration by microspectrofluorimetry, and perfusion of patch clamp pipettes in the whole-cell configuration while monitoring the activity of Ca2+-activated K+ channels as an indicator of intracellular Ca2+. We report here that inositol 1,4,5-trisphosphate serves as a signal that is both necessary and sufficient for receptor activation of Ca2+ entry across the plasma membrane in these cells.
RP BIRD, GS (corresponding author), NIEHS, CELLULAR & MOLEC PHARMACOL LAB, CALCIUM REGULAT SECT, RES TRIANGLE PK, NC 27709 USA.
NR 32
TC 175
Z9 183
U1 0
U2 4
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 162
EP 165
DI 10.1038/352162a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700059
PM 1648669
DA 2026-03-10
ER

PT J
AU HSU, VW
   YUAN, LC
   NUCHTERN, JG
   LIPPINCOTTSCHWARTZ, J
   HAMMERLING, GJ
   KLAUSNER, RD
AF HSU, VW
   YUAN, LC
   NUCHTERN, JG
   LIPPINCOTTSCHWARTZ, J
   HAMMERLING, GJ
   KLAUSNER, RD
TI A RECYCLING PATHWAY BETWEEN THE ENDOPLASMIC-RETICULUM AND THE GOLGI-APPARATUS FOR RETENTION OF UNASSEMBLED MHC CLASS-I MOLECULES
SO NATURE
LA English
DT Article
ID heavy-chains; brefeldin-a; proteins; er; antibody; receptor; complex
AB ASSEMBLY of Class I major histocompatibility complex (MHC) molecules involves the interaction of two distinct polypeptides (the heavy and light chains) with peptide antigen. Cell lines synthesizing both chains but expressing low levels of MHC class I molecules on their surface as a result of a failure in assembly and transport have been identified 1.  We now report that although the apparent steady-state distribution in these cells of class I molecules is in the endoplasmic reticulum (ER), the molecules in fact are recycled between the ER and Golgi, rather than retained in the ER. This explains the failure of class I molecules to negotiate the secretory pathway. Class I molecules do not seem to be modified by Golgi enzymes, suggesting that the proteins do not reach the Golgi apparatus during recycling. But morphological and subcellular fractionation evidence indicates that they pass through the cis Golgi or a Golgi-associated organelle, which we postulate to be the recycling organelle. This compartment, which we call the 'cis-Golgi network', would thereby be a sorting organelle that selects proteins for return to the ER.
C1 GERMAN CANC RES CTR,INST IMMUNOL & GENET,W-6900 HEIDELBERG,GERMANY.
C3 Helmholtz Association; German Cancer Research Center (DKFZ)
RP HSU, VW (corresponding author), NICHHD,CELL BIOL & METAB BRANCH,BETHESDA,MD 20892, USA.
NR 14
TC 164
Z9 174
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 441
EP 444
DI 10.1038/352441a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600069
PM 1861723
DA 2026-03-10
ER

PT J
AU MAYER, U
   RUIZ, RAT
   BERLETH, T
   MISERA, S
   JURGENS, G
AF MAYER, U
   RUIZ, RAT
   BERLETH, T
   MISERA, S
   JURGENS, G
TI MUTATIONS AFFECTING BODY ORGANIZATION IN THE ARABIDOPSIS EMBRYO
SO NATURE
LA English
DT Article
ID drosophila-melanogaster; larval cuticle; zygotic loci; pattern; chromosome; polarity
AB A systematic search for mutations in the flowering plant Arabidopsis thaliana that disrupt the spatial organization of the seedling by altering embryogenesis is described.  Mutations in nine genes affect three different aspects of the body organization:  apical-basal pattern along the single axis of polarity, radial pattern involving the primary tissues, and shape.  The results suggest principles of pattern formation in the plant embryo.
C1 UNIV MUNICH,INST GENET & MIKROBIOL,LEHRSTUHL GENET,MARIA WARD STR 1A,W-8000 MUNICH 19,GERMANY.
C3 University of Munich
NR 22
TC 453
Z9 494
U1 4
U2 63
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 402
EP 407
DI 10.1038/353402a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600047
DA 2026-03-10
ER

PT J
AU BILLIRIS, H
   PARADISSIS, D
   VEIS, G
   ENGLAND, P
   FEATHERSTONE, W
   PARSONS, B
   CROSS, P
   RANDS, P
   RAYSON, M
   SELLERS, P
   ASHKENAZI, V
   DAVISON, M
   JACKSON, J
   AMBRASEYS, N
AF BILLIRIS, H
   PARADISSIS, D
   VEIS, G
   ENGLAND, P
   FEATHERSTONE, W
   PARSONS, B
   CROSS, P
   RANDS, P
   RAYSON, M
   SELLERS, P
   ASHKENAZI, V
   DAVISON, M
   JACKSON, J
   AMBRASEYS, N
TI GEODETIC DETERMINATION OF TECTONIC DEFORMATION IN CENTRAL GREECE FROM 1900 TO 1988
SO NATURE
LA English
DT Article
ID alpine-himalayan belt; active tectonics; region; rates; asia
AB The Global Positioning System has been used to measure the relative displacements of fifteen monuments in a hundred-year-old triangulation network spanning part of the Aegean extensional basin.  These displacements reflect the tectonic deformation of the region over the past century, showing more than one metre of north-south extension across the network.  The crust in this region appears to contain a few slowly deforming blocks separated by more rapidly deforming zones.
C1 UNIV NOTTINGHAM,INST ENGN SURVEYING & SPACE GEODESY,NOTTINGHAM NG7 2RD,ENGLAND.
   UNIV LONDON IMPERIAL COLL SCI & TECHNOL,DEPT CIVIL ENGN,LONDON SW7 2BU,ENGLAND.
   UNIV OXFORD,DEPT EARTH SCI,OXFORD OX1 3PR,ENGLAND.
   UNIV NEWCASTLE UPON TYNE,DEPT SURVEYING,NEWCASTLE TYNE NE1 7RU,TYNE & WEAR,ENGLAND.
   UNIV CAMBRIDGE,DEPT EARTH SCI,CAMBRIDGE CB2 3EQ,ENGLAND.
C3 University of Nottingham; Imperial College London; University of Oxford; Newcastle University - UK; University of Cambridge
RP BILLIRIS, H (corresponding author), NATL TECH UNIV ATHENS,DEPT SURVEYING,GR-15773 ATHENS,GREECE.
NR 23
TC 165
Z9 170
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 124
EP 129
DI 10.1038/350124a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500047
DA 2026-03-10
ER

PT J
AU BAICHWAL, VR
   PARK, A
   TJIAN, R
AF BAICHWAL, VR
   PARK, A
   TJIAN, R
TI V-SRC AND EJ RAS ALLEVIATE REPRESSION OF C-JUN BY A CELL-SPECIFIC INHIBITOR
SO NATURE
LA English
DT Article
ID proto-oncogene; fibroblasts; ap-1; gene; tpa; transcription
AB THE AP-1 family of transcription factors, which includes the proto-oncogene products c-Jun and c-Fos 1, controls the stimulation of cellular genes by growth factors and the expression of oncogenes, including src and ras 2-8.  Transcriptional activation by c-Jun is regulated by a cell-type-specific inhibitor that represses the activity of a transcriptional activation domain (A1) of c-Jun by operating through the adjacent negative regulatory region (delta) (refs 9-11).   Here we show that cotransfection of the src or ras oncogene enhances the transcriptional activity of a GAL4:c-Jun hybrid that includes the delta-A1 region of c-Jun, suggesting that the DNA binding and dimerization domain of c-Jun is not required for stimulation by Src or Ras.  Moreover, induction of c-Jun activity by Src and Ras occurs in cell lines containing the c-Jun inhibitor but not in a cell line lacking it.  The region in c-Jun essential for the stimulatory action of these oncogenes maps to domain A1.  These findings suggest the existence of signal-transduction pathways that result in an increase in transcriptional activity of c-Jun and AP-1 by disrupting the c-Jun:inhibitor interaction.
C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720.
C3 University of California System; University of California Berkeley
RP BAICHWAL, VR (corresponding author), UNIV CALIF BERKELEY,HOWARD HUGHES MED INST,BERKELEY,CA 94720, USA.
NR 17
TC 84
Z9 88
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 165
EP 168
DI 10.1038/352165a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700060
PM 1906140
DA 2026-03-10
ER

PT J
AU LIN, YS
   HA, I
   MALDONADO, E
   REINBERG, D
   GREEN, MR
AF LIN, YS
   HA, I
   MALDONADO, E
   REINBERG, D
   GREEN, MR
TI BINDING OF GENERAL TRANSCRIPTION FACTOR TFIIB TO AN ACIDIC ACTIVATING REGION
SO NATURE
LA English
DT Article
ID rna polymerase-ii; gal4 derivatives; tata-box; initiation; mechanism; cloning; domain
AB A CENTRAL issue in eukaryotic transcriptional regulation is the mechanism by which promoter-specific transcription factors (activators) stimulate transcription.  Two lines of evidence indicate that the general transcription factor TFIIB is a pivotal component in the mechanism by which an acidic activator functions.  First, during assembly of the preinitiation complex TFIIB binding is a rate-limiting step enhanced by an acidic activator 1.  Second, the TFIIB activity in a HeLa cell nuclear extract is specifically retained on a column containing an acidic activating region 1.  But because our previous study monitored only TFIIB activity, it remains possible that the interaction between TFIIB and the acidic activating region is mediated through additional proteins, for example, those designated as adaptors 2, coactivators 3 or mediators 4,5.  A complementary clone encoding TFIIB has recently been isolated and shown to encode a polypeptide of relative molecular mass 35,000 (ref. 6).  Here we report that TFIIB expressed in and purified from Escherichia coli (recombinant TFIIB) binds directly to the potent acidic activating region of the herpes simplex virus-1 VP16 protein.
C1 UNIV MED & DENT NEW JERSEY,ROBERT WOOD JOHNSON MED SCH,DEPT BIOCHEM,PISCATAWAY,NJ 08854.
C3 Rutgers University System; Rutgers University New Brunswick; Rutgers University Biomedical & Health Sciences
RP LIN, YS (corresponding author), UNIV MASSACHUSETTS,MED CTR,PROGRAM MOLEC MED,373 PLANTAT ST,WORCESTER,MA 01605, USA.
NR 19
TC 344
Z9 383
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 569
EP 571
DI 10.1038/353569a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300071
PM 1922364
DA 2026-03-10
ER

PT J
AU HOCH, B
   MAIER, RM
   APPEL, K
   IGLOI, GL
   KOSSEL, H
AF HOCH, B
   MAIER, RM
   APPEL, K
   IGLOI, GL
   KOSSEL, H
TI EDITING OF A CHLOROPLAST MESSENGER-RNA BY CREATION OF AN INITIATION CODON
SO NATURE
LA English
DT Article
ID nucleotide-sequence; plant-mitochondria; gene organization; dna-sequence; genome; maize; map
AB PRIMARY mRNA transcripts in several systems are edited by single base substitutions, small deletions or insertions to yield functional messenger RNA species 1,2.  Mitochondrial mRNAs in particular, including those from plants 3-5, seem to be the subject of extensive editing, unlike mRNAs encoded by chloroplast DNA, for which the prediction of amino-acid sequence from the corresponding gene sequence is generally unambiguous 6-8.  Occasionally, however, an ACG codon appears at the 5' terminus of chloroplast genes, where the initiation codon ATG would be expected. Here we present evidence for a C --> U editing that is responsible for the conversion of the ACG codon to an AUG initiation codon in the mRNA transcript from the rpl2 gene of the maize plastome, showing that mRNA editing can also occur in chloroplasts.
RP HOCH, B (corresponding author), UNIV FREIBURG,INST BIOL 3,SCHANZLE STR 1,W-7800 FREIBURG,GERMANY.
NR 18
TC 290
Z9 325
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 178
EP 180
DI 10.1038/353178a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100057
PM 1653905
DA 2026-03-10
ER

PT J
AU WATSON, SR
   FENNIE, C
   LASKY, LA
AF WATSON, SR
   FENNIE, C
   LASKY, LA
TI NEUTROPHIL INFLUX INTO AN INFLAMMATORY SITE INHIBITED BY A SOLUBLE HOMING RECEPTOR-IGG CHIMERA
SO NATURE
LA English
DT Article
ID monoclonal-antibody; glycoprotein; invivo; lymphocytes; prevention; platelets; adhesion; proteins; cloning
AB Neutrophil-mediated inflammation is involved in a number of human clinical manifestations, including the adult respiratory distress syndrome, multi-organ failure and reperfusion injury 1.  One way of inhibiting this type of inflammatory response would be to block competitively the adhesive interactions between neutrophils and the endothelium adjacent to the inflamed region 2.  The lectin-containing 3,4 murine adhesion molecule gp90MET, the homing receptor, is found on all leukocytic cells, including neutrophils. 5  MEL 14, a monoclonal antibody directed against this adhesion molecule, blocks lymphocyte traffic to lymph nodes 6 and extravasation of neutrophils from blood to inflammatory sites 7.  Here we show that administration to mice of a soluble immunoglobulin chimaera containing the murine homing receptor extracellular domain significantly decreases the number of neutrophils that migrate to the peritoneum in response to the inflammatory irritant thioglycollate.  These results indicate that soluble forms of a single type of adhesion molecule, the homing receptor, could be clinically effective compounds for the inhibition of neutrophil-mediated inflammation.
RP WATSON, SR (corresponding author), GENENTECH INC,DEPT IMMUNOBIOL,460 POINT SAN BRUNO BLVD,S SAN FRANCISCO,CA 94080, USA.
NR 23
TC 297
Z9 373
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 164
EP 166
DI 10.1038/349164a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800061
PM 1986307
DA 2026-03-10
ER

PT J
AU MATSUI, M
   PRICE, GD
AF MATSUI, M
   PRICE, GD
TI SIMULATION OF THE PRE-MELTING BEHAVIOR OF MGSIO3 PEROVSKITE AT HIGH-PRESSURES AND TEMPERATURES
SO NATURE
LA English
DT Article
ID molecular-dynamics simulation; lower mantle conditions; geophysical implications; electrical-conductivity; transitions
AB MAGNESIUM-rich silicate perovskite is thought to be the dominant mineral phase in the Earth's lower mantle. The behaviour of MgSiO3 perovskite at high temperatures and pressures is therefore important for a wide range of geophysical problems, including the chemical and thermal evolution of the Earth, mantle convection, the thermal gradient in the mantle and the secular variations of the Earth's magnetic field. Experimental investigations at lower-mantle conditions are, however, difficult. We have performed computer simulations of MgSiO3 perovskite under typical lower mantle pressures and temperatures using the constant-temperature and constant-pressure molecular dynamics (MD) method. At pressures above 10 GPa, our simulations suggest that orthorhombic MgSiO3 perovskite undergoes a temperature-induced phase transformation to a cubic (or pseudo-cubic) phase before melting, and that the cubic phase is a solid electrolyte. The MD method tends to overestimate the temperature of melting and related phenomena, but should provide a reliable qualitative description of the ionic-conductivity behaviour. Quantitative determination of the structure and ionic conductivity of MgSiO3 perovskite at lower-mantle conditions must, however, await improvements in both experimental and simulation techniques.
C1 KANAZAWA MED UNIV,CHEM LAB,KAHOKU,ISHIKAWA 92002,JAPAN.
C3 Kanazawa Medical University
RP MATSUI, M (corresponding author), UNIV LONDON UNIV COLL,DEPT GEOL SCI,GOWER ST,LONDON WC1E 6BT,ENGLAND.
NR 25
TC 98
Z9 100
U1 0
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 735
EP 737
DI 10.1038/351735a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100060
DA 2026-03-10
ER

PT J
AU PETRENKO, AG
   PERIN, MS
   DAVLETOV, BA
   USHKARYOV, YA
   GEPPERT, M
   SUDHOF, TC
AF PETRENKO, AG
   PERIN, MS
   DAVLETOV, BA
   USHKARYOV, YA
   GEPPERT, M
   SUDHOF, TC
TI BINDING OF SYNAPTOTAGMIN TO THE ALPHA-LATROTOXIN RECEPTOR IMPLICATES BOTH IN SYNAPTIC VESICLE EXOCYTOSIS
SO NATURE
LA English
DT Article
ID widow spider venom; frog neuromuscular-junction; long-term potentiation; protein kinase-c; nerve-terminals; purification; membrane
AB A VERTEBRATE neurotoxin, alpha-latrotoxin, from black widow spider venom causes synaptic vesicle exocytosis and neurotransmitter release from presynaptic nerve terminals 1-4.  Although the mechanism of action of alpha-latrotoxin is not known, it does require binding of alpha-latrotoxin to a high-affinity receptor on the presynaptic plasma membrane 5.  The alpha-latrotoxin receptor seems to be exclusively at the presynaptic plasmamembrane 6.  Here we report that the alpha-latrotoxin receptor specifically binds to a synaptic vesicle protein, synaptotagmin, and modulates its phosphorylation. Synaptotagmin is a synaptic vesicle-specific membrane protein that binds negatively charged phospholipids and contains two copies of a putative Ca2+-binding domain from protein kinase C (the C2-domain), suggesting a regulatory role in synaptic vesicle fusion 7,8.  Our findings suggest that a physiological role of the alpha-latrotoxin receptor may be the docking of synaptic vesicles at the active zone. The direct interaction of the alpha-latrotoxin receptor with a synaptic vesicle protein also suggests a mechanism of action for this toxin in causing neurotransmitter release.
C1 UNIV TEXAS,SW MED CTR,DALLAS,TX 75235.
   UNIV TEXAS,SW MED CTR,DEPT MOLEC GENET,DALLAS,TX 75235.
   SHEMYAKIN BIOORGAN CHEM INST,MOSCOW 117871,USSR.
C3 University of Texas System; University of Texas Dallas; University of Texas Southwestern Medical Center; University of Texas System; University of Texas Southwestern Medical Center; University of Texas Dallas; Russian Academy of Sciences; Pushchino Scientific Center for Biological Research (PSCBI) of the Russian Academy of Sciences; Institute of Bioorganic Chemistry of the Russian Academy of Sciences
NR 20
TC 230
Z9 241
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 65
EP 68
DI 10.1038/353065a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500058
PM 1881448
DA 2026-03-10
ER

PT J
AU DOOLEY, DM
   MCGUIRL, MA
   BROWN, DE
   TUROWSKI, PN
   MCINTIRE, WS
   KNOWLES, PF
AF DOOLEY, DM
   MCGUIRL, MA
   BROWN, DE
   TUROWSKI, PN
   MCINTIRE, WS
   KNOWLES, PF
TI A CU(I)-SEMIQUINONE STATE IN SUBSTRATE-REDUCED AMINE OXIDASES
SO NATURE
LA English
DT Article
ID benzylamine oxidase; pig plasma
AB THE role of copper in copper-containing amine oxidases has long been a source of debate and uncertainty1.  Numerous electron paramagnetic resonance (EPR) experiments 2-6, including rapid freeze-quench studies 7, have failed to detect changes in the copper oxidation state in the presence of substrate amines.  One suggestion that copper reduction might occur 8, has never been confirmed.  Copper amine oxidases contain another cofactor, recently identified as 6-hydroxydopa quinone (topa quinone) 9, which is reduced by substrates.  Copper has been implicated in the reoxidation of the substrate-reduce enzyme 10-12, but the failure to detect any copper redox change has led to proposals that Cu(II) acts as a Lewis acid 13, that it has an indirect role in catalysis 14, or that it serves a structural role 6.  We present evidence for the generation of a Cu(I)-semiquinone state by substrate reduction of several amine oxidases under anaerobic conditions, and suggest that the Cu(I)-semiquinone may be the catalytic intermediate that reacts directly with oxygen.
C1 VET ADM MED CTR,DEPT MOLEC BIOL,SAN FRANCISCO,CA 94121.
   UNIV LEEDS,DEPT BIOCHEM & BIOPHYS,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND.
C3 US Department of Veterans Affairs; Veterans Health Administration (VHA); University of Leeds
RP DOOLEY, DM (corresponding author), AMHERST COLL,DEPT CHEM,AMHERST,MA 01002, USA.
NR 21
TC 252
Z9 264
U1 1
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 262
EP 264
DI 10.1038/349262a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900064
PM 1846226
DA 2026-03-10
ER

PT J
AU TATSUMISAGO, M
   SHINKUMA, Y
   MINAMI, T
AF TATSUMISAGO, M
   SHINKUMA, Y
   MINAMI, T
TI STABILIZATION OF SUPERIONIC ALPHA-AGL AT ROOM-TEMPERATURE IN A GLASS MATRIX
SO NATURE
LA English
DT Article
ID high ionic conductivity; solid-state ionics; system
AB SINCE the discovery 1 that the high-temperature phase of silver iodide (alpha-AgI) has an ionic conductivity comparable to that of the best liquid electrolytes, solid electrolytes have attracted wide interest. Possible applications of these materials range from solid-state batteries to electrochromic displays and sensors 2.  Although alpha-AgI displays conductivities of more than 10 S cm-1 (ref. 3), owing to the almost liquid-like mobility of Ag+ ions, the crystal transforms below 147-degrees-C to the beta-phase with a conductivity of only approximately 10(-5) S cm-1 at room temperature. Efforts to achieve good conductivities at lower temperatures have focused on the addition of a second component to AgI to form solid solutions or new compounds such as RbAg4I5 and Ag2HgI4 (refs 4-7). Here we report our success in depressing the alpha --> beta-transformation temperature so as to stabilize alpha-AgI itself at room temperature. We use a melt-quenching technique to prepare crystallites of alpha-AgI frozen into a silver borate glass matrix. The quenched material showed diffraction peaks characteristic of alpha-AgI and displayed ionic conductivities of about 10(-1) S cm-1. Further development of these glass/crystal composites may make the high ionic conductivity of alpha-AgI available for room-temperature solid-state applications.
RP TATSUMISAGO, M (corresponding author), UNIV OSAKA PREFECTURE,DEPT APPL CHEM,SAKAI,OSAKA 591,JAPAN.
NR 19
TC 209
Z9 217
U1 1
U2 86
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 217
EP 218
DI 10.1038/354217a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800044
DA 2026-03-10
ER

PT J
AU TANAKA, K
   OSHIMURA, M
   KIKUCHI, R
   SEKI, M
   HAYASHI, T
   MIYAKI, M
AF TANAKA, K
   OSHIMURA, M
   KIKUCHI, R
   SEKI, M
   HAYASHI, T
   MIYAKI, M
TI SUPPRESSION OF TUMORIGENICITY IN HUMAN COLON-CARCINOMA CELLS BY INTRODUCTION OF NORMAL CHROMOSOME-5 OR CHROMOSOME-18
SO NATURE
LA English
DT Article
ID familial polyposis coli; colorectal carcinomas; constitutional heterozygosity; gene; assignment; tumors; arm
AB DEVELOPMENT of colon carcinomas can be associated with allelic deletions on several chromosomes, including 5q and 18q (refs 1-10).  The APC gene11-13 on 5q and the DCC gene14 on 18q have been identified as potential tumor suppressor genes, whose suppression contributes to colon carcinogenesis.  To investigate the role of genes in these deleted regions, we have now introduced a single normal human chromosome into a human colon carcinoma cell line, COKFu, through microcell hybridization15-20.  Several clones of hybrid cells containing normal chromosome 5, and others containing normal chromosome 18, were obtained.  The morphology of the hybrid cells was markedly altered:  the hybrids with chromosome 5 exhibited a closely packed polygonal morphology, and the hybrid cells with chromosome 18 were flattened.  The cloning efficiency of the hybrid cells in soft agar was reduced from 0.46 to 0% of that of the parental carcinoma cells, and the tumorigenicity of these hybrid cells in athymic nude mice was completely suppressed.  The growth properties of the hybrid cells with chromosome 11 were not substantially changed.  These results strongly suggest that the genes on normal chromosome 5 and 18 function as tumor suppressors in colon carcinogenesis.
C1 TOTTORI UNIV,FAC MED,DEPT MOLEC & CELL GENET,YONAGO,TOTTORI 683,JAPAN.
C3 Tottori University
RP TANAKA, K (corresponding author), TOKYO METROPOLITAN INST MED SCI,DEPT BIOCHEM,3-18-22 HONKOMAGOME,BUNKYO KU,TOKYO 113,JAPAN.
NR 25
TC 185
Z9 201
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 340
EP 342
DI 10.1038/349340a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100056
PM 1670965
DA 2026-03-10
ER

PT J
AU GATTESCHI, D
   PARDI, L
   BARRA, AL
   MULLER, A
   DORING, J
AF GATTESCHI, D
   PARDI, L
   BARRA, AL
   MULLER, A
   DORING, J
TI LAYERED MAGNETIC-STRUCTURE OF A METAL CLUSTER ION
SO NATURE
LA English
DT Article
AB THE ability of molecular materials to perform many of the optical, electronic and magnetic functions traditionally associated with extended two- and three-dimensional inorganic solids 1,2 has given rise to intensive research on molecular electronics 3,4. In the course of investigating the properties of a class of anionic metal clusters based on the vanadium oxide systems 5-8, which bear analogy with those of bulk solid material 6, we have encountered unusual magnetic behaviour in a finite molecular system. A cluster containing 15 paramagnetic vanadium atoms consists of three distinct layers in each of which the magnetization shows a distinct temperature dependence. Analogous behaviour in bulk systems can be found in magnetic multilayers 9 and also in copper oxide superconductors, where copper layers with strong antiferromagnetic coupling are separated by layers of rare-earth ions in which the coupling is very weak 10. The behaviour of this cluster suggests the possibility of applications for molecular-scale switching.
C1 UNIV BIELEFELD,FAK CHEM,W-4800 BIELEFELD,GERMANY.
C3 University of Bielefeld
RP GATTESCHI, D (corresponding author), UNIV FLORENCE,DIPARTMENTO CHIM,I-50121 FLORENCE,ITALY.
NR 16
TC 195
Z9 198
U1 0
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 463
EP 465
DI 10.1038/354463a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800054
DA 2026-03-10
ER

PT J
AU KAY, GF
   ASHWORTH, A
   PENNY, GD
   DUNLOP, M
   SWIFT, S
   BROCKDORFF, N
   RASTAN, S
AF KAY, GF
   ASHWORTH, A
   PENNY, GD
   DUNLOP, M
   SWIFT, S
   BROCKDORFF, N
   RASTAN, S
TI A CANDIDATE SPERMATOGENESIS GENE ON THE MOUSE Y-CHROMOSOME IS HOMOLOGOUS TO UBIQUITIN-ACTIVATING ENZYME-E1
SO NATURE
LA English
DT Article
ID l-cell defect; x-chromosome; sex determination; dna-replication; short arm; expression; differentiation; complements; cloning; antigen
AB THE human X-linked gene A1S9 (refs 1-3) complements a temperature-sensitive cell-cycle mutation in mouse L cells 4, and encodes the ubiquitin-activating enzyme E1 (refs 5-7). The gene has been reported to escape X-chromosome inactivation 8, but there is some conflicting evidence 9. We have isolated part of the mouse A1s9 gene, mapped it to the proximal portion of the X chromosome and shown that it undergoes normal X-inactivation. We also detected two copies of the gene on the short arm of the mouse Y chromosome (A1s9Y-1 and A1s9Y-2). The functional A1s9Y gene (Als9Y-1) is expressed in testis and is lost in the deletion mutant Sxr(b) (ref. 10). Therefore A1s9Y-1 is a candidate for the spermatogenesis gene, Spy, which maps to this region. A1s9X is similar to the Zfx gene in undergoing X-inactivation 11,12, yet having homologous sequences on the short arm of the Y chromosome 13,14, which are expressed in the testis. These Y-linked genes may form part of a coregulated group of genes which function during spermatogenesis.
C1 MRC,CLIN RES CTR,COMPARAT BIOL SECT,HARROW HA1 3UJ,MIDDX,ENGLAND.
   INST CANC RES,CHESTER BEATTY LABS,LONDON SW3 6JB,ENGLAND.
C3 Medical Research Council Clinical Trials Unit; Royal Marsden NHS Foundation Trust; University of London; Institute of Cancer Research - UK
RP RASTAN, S (corresponding author), MRC,CLIN RES CTR,COMPARAT BIOL SECT,HARROW HA1 3UJ,MIDDX,ENGLAND.
NR 30
TC 114
Z9 124
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 486
EP 489
DI 10.1038/354486a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800063
PM 1749428
DA 2026-03-10
ER

PT J
AU BARTEL, N
   RUPEN, MP
   SHAPIRO, II
   PRESTON, RA
   RIUS, A
AF BARTEL, N
   RUPEN, MP
   SHAPIRO, II
   PRESTON, RA
   RIUS, A
TI A HIGH-RESOLUTION RADIO IMAGE OF A YOUNG SUPERNOVA
SO NATURE
LA English
DT Article
ID vlbi observations; sn-1986j; emission
AB Supernovae in our own Galaxy are so rare that images of their remnants 1 can show only the late aftermath of an explosion that occurred anything from a few hundred to several tens of thousands of years ago.  Young supernovae are seen frequently in other galaxies, but because they are more distant, it has not been possible until now to obtain high-resolution images that would reveal details of the explosion and the immediate development of the ejected material.  Here we present a very-long-baseline interferometric (VLBI) radio image of the bright supernova 1986J, which occurred in the galaxy NGC891 at a distance of approximately 12 Mpc.  No detailed image of any supernova or remnant has been obtained before so soon after the explosion.  Our image shows a shell of emission with jet-like protrusions.  Their analysis should advance our understanding of the dynamics of the expanding debris, the dissipation of energy into the surrounding circumstellar medium, and the evolution of the supernova into the remnant.
C1 CALTECH,JET PROP LAB,PASADENA,CA 91109.
   FAC CIENCIAS MATEMAT MADRID,INST ASTRON & GEODESIA,E-28040 MADRID,SPAIN.
C3 National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; Consejo Superior de Investigaciones Cientificas (CSIC); CSIC-UCM - Instituto de Astronomia y Geodesia (IAG)
RP BARTEL, N (corresponding author), HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138, USA.
NR 24
TC 38
Z9 39
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 212
EP 214
DI 10.1038/350212a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900049
DA 2026-03-10
ER

PT J
AU BALLY, J
   LEVENTHAL, M
AF BALLY, J
   LEVENTHAL, M
TI IS THE GALACTIC-CENTER GAMMA-RAY SOURCE 1E1740.7-2942 ACCRETING FROM A MOLECULAR CLOUD
SO NATURE
LA English
DT Article
ID positron-annihilation radiation; center region; galaxy
AB FOR twenty years there have been detections of an intermittent source of 511-keV electron-positron annihilation radiation at the centre of our Galaxy 1-3.  Until recently, none of the balloon or satellite experiments lucky enough to catch the source in its 'on' state had spatial resolution better than several degrees, but on 13-14 October 1990 the French SIGMA experiment aboard the Soviet GRANAT spacecraft observed a day-long burst of narrow-band gamma-rays, probably annihilation radiation, from within 1.5 arcmin of the known X-ray source 1E1740.7-2942, about 50 arcmin from Sgr A West, which contains the dynamical centre of the Milky Way 4-6.  Here we report millimetre-wavelength observations showing that this variable X-ray source lies on a line of sight to the dense 10(5) M. molecular cloud G-0.86-0.08, near the Galactic Centre. We suggest that the gamma-ray source, probably a compact object, possibly a black hole, is accreting dense gas directly from the molecular cloud.
C1 AT&T BELL LABS,MURRAY HILL,NJ 07974.
C3 AT&T; Nokia Corporation; Nokia Bell Labs
RP BALLY, J (corresponding author), AT&T BELL LABS,HOH L-245,HOLMDEL,NJ 07733, USA.
NR 27
TC 84
Z9 84
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 234
EP 237
DI 10.1038/353234a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400050
DA 2026-03-10
ER

PT J
AU FLEMING, RM
   RAMIREZ, AP
   ROSSEINSKY, MJ
   MURPHY, DW
   HADDON, RC
   ZAHURAK, SM
   MAKHIJA, AV
AF FLEMING, RM
   RAMIREZ, AP
   ROSSEINSKY, MJ
   MURPHY, DW
   HADDON, RC
   ZAHURAK, SM
   MAKHIJA, AV
TI RELATION OF STRUCTURE AND SUPERCONDUCTING TRANSITION-TEMPERATURES IN A3C60
SO NATURE
LA English
DT Article
ID system
AB THE discovery of conductivity 1 in A(x)C60 (where A represents an alkali metal) and superconductivity 2 in K(x)C60 has been followed by reports of superconductivity in other alkali-metal-doped fullerides with transition temperatures as high as 33 K (ref. 3).  Elucidation of phase diagrams and understanding the relationship between structure and superconducting properties is essential to a detailed understanding of superconductivity in these systems.  So far, structural data have been reported only for the non-conducting, intercalated body-centred cubic (b.c.c.) structures A6C60 (where A is K or Cs; ref. 4), a body-centred tetragonal structure for A4C60 (where A is K, Rb, Cs; ref. 5) and the superconducting, intercalated face-centred cubic (f.c.c.) material K3C60 (ref. 6).  Here we report the preparation of a series of single-phase, isostructural f.c.c. superconductors with composition A3C60 (where A is K, Rb, Cs or a mixture of these), and show that T(c) increases monotonically with the size of the unit cell.  Extended Huckel band-structure calculations also show a monotonic increase in the density of states at the Fermi level, N(E(F)), with lattice parameter.  The primary implication of these results is that all A3C60 superconductors have the same structure and that changes in T(c) can be accounted for by changes in N(E(F)).
RP FLEMING, RM (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 18
TC 537
Z9 548
U1 2
U2 77
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 787
EP 788
DI 10.1038/352787a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400053
DA 2026-03-10
ER

PT J
AU BERRY, MJ
   BANU, L
   CHEN, Y
   MANDEL, SJ
   KIEFFER, JD
   HARNEY, JW
   LARSEN, PR
AF BERRY, MJ
   BANU, L
   CHEN, Y
   MANDEL, SJ
   KIEFFER, JD
   HARNEY, JW
   LARSEN, PR
TI RECOGNITION OF UGA AS A SELENOCYSTEINE CODON IN TYPE-I DEIODINASE REQUIRES SEQUENCES IN THE 3' UNTRANSLATED REGION
SO NATURE
LA English
DT Article
ID nucleotide-sequence; cdna; expression
AB SELENOCYSTEINE is incorporated cotranslationally at UGA codons, normally read as stop codons, in several bacterial proteins 1,2 and in the mammalian proteins glutathione peroxidase (GPX) 3-5, selenoprotein P 6 and Type I iodothyronine 5' deiodinase (5'DI) 7.  Previous analyses in bacteria have suggested that a stem-loop structure involving the UGA codon and adjacent sequences is necessary and sufficient for selenocysteine incorporation into formate dehydrogenase and glycine reductase 2,8,9.  We used the recently cloned 5'DI to investigate selenoprotein synthesis in eukaryotes. We show that successful incorporation of selenocysteine into this enzyme requires a specific 3' untranslated (3'ut) segment of about 200 nucleotides, which is found in both rat and human 5'DI messenger RNAs. These sequences are not required for expression of a cysteine-mutant deiodinase. Although there is little primary sequence similarity between the 3'ut regions of these mRNAs and those encoding GPX, the 3'ut sequences of rat GPX can substitute for the 5'DI sequences in directing selenocysteine insertion. Computer analyses predict similar stem-loop structures in the 3'ut regions of the 5'DI and GPX mRNAs. Limited mutations in these structures reduce or eliminate their capacity to permit 5'DI translation. These results identify a 'selenocysteine-insertion sequence' motif in the 3'ut region of these mRNAs that is essential for successful translation of 5'DI, presumably GPX, and possibly other eukaryotic selenocysteine-containing proteins.
C1 BRIGHAM & WOMENS HOSP,DEPT MED,DIV THYROID,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,BOSTON,MA 02115.
C3 Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical School
RP BERRY, MJ (corresponding author), BRIGHAM & WOMENS HOSP,HOWARD HUGHES MED INST,75 FRANCIS ST,BOSTON,MA 02115, USA.
NR 15
TC 554
Z9 632
U1 1
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 273
EP 276
DI 10.1038/353273a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400065
PM 1832744
DA 2026-03-10
ER

PT J
AU OGAWA, K
AF OGAWA, K
TI 4 ATP-BINDING SITES IN THE MIDREGION OF THE BETA-HEAVY CHAIN OF DYNEIN
SO NATURE
LA English
DT Article
ID urchin sperm flagella; photosensitized cleavage; tau-protein; fragment-a; outer arm; sequence; irradiation; subunits; enzymes; motor
AB THE 'motor' proteins of eukaryotic cells contain specialized domains that hydrolyse ATP to produce force and movement along a cytoskeletal polymer (actin in the case of the myosin family; microtubules in the case of the kinesin family and dyneins). There are motor-protein superfamilies in which each member has a conserved force-generating domain joined to a different 'tail' which conveys specific attachment properties (see ref. 1 for a review). The minus-end-directed microtubule motors, the dyneins 2, may also constitute a superfamily of force-generating proteins with distinct attachment domains 3. Axonemal outer-arm dynein from sea urchin spermatozoa is a multimeric protein consisting of two heavy chains (alpha and beta) with ATPase activity. three intermediate chains and several light chains 4. Here I report the sequence of cloned complementary DNA encoding the beta-heavy chain of a dynein motor molecule. The predicted amino-acid sequence reveals four ATP-binding consensus sequences in the central domain. The dynein beta-heavy chain is thought to associate transiently with a microtubule during ATP hydrolysis 5, but the ATP-dependent microtubule-binding sequence common to the kinesin superfamily is not found in the dynein beta-heavy chain. These unique features distinguish the dynein beta-heavy chain from other motor protein superfamilies and may be characteristic of the dynein superfamily.
RP OGAWA, K (corresponding author), NATL INST BASIC BIOL, DEPT CELL BIOL, OKAZAKI, AICHI 444, JAPAN.
NR 21
TC 174
Z9 185
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 643
EP 645
DI 10.1038/352643a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100063
PM 1830928
DA 2026-03-10
ER

PT J
AU DAVIES, CH
   STARKEY, SJ
   POZZA, MF
   COLLINGRIDGE, GL
AF DAVIES, CH
   STARKEY, SJ
   POZZA, MF
   COLLINGRIDGE, GL
TI GABA-B AUTORECEPTORS REGULATE THE INDUCTION OF LTP
SO NATURE
LA English
DT Article
ID d-aspartate receptors; collateral-commissural pathway; synaptic transmission; rat hippocampus; dependent depression; potentiation; inhibition; invitro; neurons; culture
AB UNDERSTANDING the mechanisms involved in long-term potentiation (LTP) should provide insights into the cellular and molecular basis of learning and memory in vertebrates 1. It has been established that in the CA1 region of the hippocampus the induction of LTP requires the transient activation of the N-methyl-D-aspartate (NMDA) receptor system 21. During low-frequency transmission, significant activation of this system is prevented by gamma-aminobutyric acid (GABA) mediated synaptic inhibition 3,4 which hyperpolarizes neurons into a region where NMDA receptor-operated channels are substantially blocked by Mg2+ (refs. 5, 6). But during high-frequency transmission, mechanisms are evoked that provide sufficient depolarization of the postsynaptic membrane to reduce this block 7 and thereby permit the induction of LTP. We now report that this critical depolarization is enabled because during high-frequency transmission GABA depresses its own release by an action on GABA(B) autoreceptors, which permits sufficient NMDA receptor activation for the induction of LTP. These findings demonstrate a role for GABA(B) receptors in synaptic plasticity.
C1 UNIV BIRMINGHAM, SCH MED, DEPT INTERNAL MED, BIRMINGHAM B15 2TT, W MIDLANDS, ENGLAND.
   UNIV BRISTOL, SCH MED SCI, DEPT PHARMACOL, BRISTOL BS8 1TD, AVON, ENGLAND.
C3 University of Birmingham; University of Bristol
NR 25
TC 518
Z9 568
U1 0
U2 37
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 609
EP 611
DI 10.1038/349609a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000059
PM 1847993
DA 2026-03-10
ER

PT J
AU WIGLEY, DB
   DAVIES, GJ
   DODSON, EJ
   MAXWELL, A
   DODSON, G
AF WIGLEY, DB
   DAVIES, GJ
   DODSON, EJ
   MAXWELL, A
   DODSON, G
TI CRYSTAL-STRUCTURE OF AN N-TERMINAL FRAGMENT OF THE DNA GYRASE B-PROTEIN
SO NATURE
LA English
DT Article
ID escherichia-coli; a-protein; gyrb gene; resolution; topoisomerases; refinement; complex; site
AB The crystal structure of an N-terminal fragment of the Escherichia coli DNA gyrase B protein, complexed with a nonhydrolysable ATP analogue, has been solved at 2.5 angstrom resolution.  It consists of two domains, both containing novel protein folds.  The protein fragment forms a dimer, whose N-terminal domains are responsible for ATP binding and hydrolysis.  The C-terminal domains form the sides of a 20 angstrom hole through the protein dimer which may play a role in DNA strand passage during the supercoiling reaction.
C1 UNIV LEICESTER,DEPT BIOCHEM,LEICESTER LE1 7RH,ENGLAND.
C3 University of Leicester
RP WIGLEY, DB (corresponding author), YORK UNIV,DEPT CHEM,YORK YO1 5DD,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 26
TC 509
Z9 558
U1 0
U2 30
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 624
EP 629
DI 10.1038/351624a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200055
PM 1646964
DA 2026-03-10
ER

PT J
AU PEVNY, L
   SIMON, MC
   ROBERTSON, E
   KLEIN, WH
   TSAI, SF
   DAGATI, V
   ORKIN, SH
   COSTANTINI, F
AF PEVNY, L
   SIMON, MC
   ROBERTSON, E
   KLEIN, WH
   TSAI, SF
   DAGATI, V
   ORKIN, SH
   COSTANTINI, F
TI ERYTHROID-DIFFERENTIATION IN CHIMERIC MICE BLOCKED BY A TARGETED MUTATION IN THE GENE FOR TRANSCRIPTION FACTOR GATA-1
SO NATURE
LA English
DT Article
ID dna-binding factor; stem-cells; expression; protein
AB THE zinc-finger transcription factor GATA-1 (previously known as GF-1, NF-E1 or Eryf 1 (refs 1-5)) binds to GATA consensus elements in regulatory regions of the alpha- and beta-globin gene clusters 2-6 and other erythroid cell-specific genes 7-9.  Analysis of the effects of mutations in GATA-bindig sites in cell culture and in binding assays in vitro 2,5,10,11, as well as transactivation studies with GATA-1 expression vectors in heterologous cells 12, have provided indirect evidence that this factor is involved in the activation of globin and other genes during erythroid cell maturation.  GATA-1 is also expressed in megakaryocyte 13,14 and mast cells, but not in other blood cell lineages or in non-haemopoietic cells.  To investigate the role of this factor in haematopoiesis in vivo, we disrupted the X-linked GATA-1 gene by homologous recombination in a male (XY) murine embryonic stem cell line and tested the GATA-1-deficient cells for their ability to contribute to different tissues in chimaeric mice.  The mutant embryonic stem cells contributed to all non-haemopoietic tissues tested and to a white blood cell fraction, but failed to give rise to mature red blood cells.  This demonstrates that GATA-1 is required for the normal differentiation of erythroid cells, and that other GATA-binding proteins 15,16 cannot compensate for its absence.
C1 COLUMBIA UNIV COLL PHYS & SURG,DEPT GENET & DEV,701 W 168TH ST,NEW YORK,NY 10032.
   COLUMBIA UNIV COLL PHYS & SURG,DEPT PATHOL,NEW YORK,NY 10032.
   HARVARD UNIV,CHILDRENS HOSP,SCH MED,DEPT PEDIAT,DIV HEMATOL ONCOL,BOSTON,MA 02115.
   HOWARD HUGHES MED INST,BOSTON,MA 02115.
C3 Columbia University; Columbia University; Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Harvard Medical School; Howard Hughes Medical Institute
NR 30
TC 1150
Z9 1314
U1 2
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 257
EP 260
DI 10.1038/349257a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900062
PM 1987478
DA 2026-03-10
ER

PT J
AU VOLLBRECHT, E
   VEIT, B
   SINHA, N
   HAKE, S
AF VOLLBRECHT, E
   VEIT, B
   SINHA, N
   HAKE, S
TI THE DEVELOPMENTAL GENE KNOTTED-1 IS A MEMBER OF A MAIZE HOMEOBOX GENE FAMILY
SO NATURE
LA English
DT Article
ID drosophila; antennapedia; expression; proteins; homeodomain; transcripts; sequences; region; locus
AB THE Knotted-1 (Kn1) locus is defined by several dominant gain-of-function mutations that alter leaf development.  Foci of cells along the lateral veins do not differentiate properly, but continue to divide, forming outpocketings or knots.  The ligule, a fringe normally found at the junction of leaf blade and sheath, is often displaced and perpendicular to its normal position 1-3.  The phenotype is manifested in all cell layers of the leaf blade, but is controlled by a subgroup of cells of the inner layer 4.  Mutations result from the insertion of transposable elements 5 or a tandem duplication 6.  We show that the Kn1 gene encodes a homeodomain-containing protein, the first identified in the plant kingdom.  Sequence comparisons strongly suggest that Kn1 acts as a transcription factor.  Here we use the Kn1 homeobox to isolate other expressed homeobox genes in maize.  The Kn1 homeobox may permit the isolation of genes that, like animal and fungal counterparts 7, regulate cell fate determination.
C1 USDA ARS,CTR PLANT GENE EXPRESS,800 BUCHANAN ST,ALBANY,CA 94710.
   UNIV CALIF BERKELEY,DEPT PLANT BIOL,BERKELEY,CA 94720.
C3 United States Department of Agriculture (USDA); University of California System; University of California Berkeley
NR 34
TC 632
Z9 743
U1 0
U2 115
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 241
EP 243
DI 10.1038/350241a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900061
PM 1672445
DA 2026-03-10
ER

PT J
AU VANHOOF, AAM
   LANGEREIS, CG
AF VANHOOF, AAM
   LANGEREIS, CG
TI REVERSAL RECORDS IN MARINE MARLS AND DELAYED ACQUISITION OF REMANENT MAGNETIZATION
SO NATURE
LA English
DT Article
ID miocene-pliocene boundary; geomagnetic-field; sediments; magnetite; polarity; age
AB RECORDS of geomagnetic reversals 'frozen' into the magnetic components of sediments provide a means to study the time-dependent behaviour of the geomagnetic field during polarity transitions.  Although sedimentary records have the advantage of being readily available and continuous, the process by which they acquire a remanent magnetization is still not fully understood 1.  Magnetites, which lose their magnetization at relatively high temperatures (less-than-or-similar-to 50-degrees-C) are generally considered to carry the primary remanence of the sediment - that is, to record the palaeomagnetic direction.  Here we describe two reversed-to-normal transitional records from marine marls in which this high-temperature component shows a delayed remanence acquisition relative to a lower-temperature component.  In these samples, therefore, the high-temperature component does not reflect geomagnetic changes during the reversal.  At least for marine marls, detailed palaeomagnetic, rock-magnetic and geochemical studies are apparently necessary to judge the validity of reversal records.
RP VANHOOF, AAM (corresponding author), PALAEOMAGNET LAB FT HOOFDDIJK,BUDAPESTLAAN 17,3584 CD UTRECHT,NETHERLANDS.
NR 25
TC 72
Z9 72
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 223
EP 225
DI 10.1038/351223a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000053
DA 2026-03-10
ER

PT J
AU GASSE, F
   ARNOLD, M
   FONTES, JC
   FORT, M
   GIBERT, E
   HUC, A
   LI, BY
   LI, YF
   LJU, Q
   MELIERES, F
   VANCAMPO, E
   WANG, FB
   ZHANG, QS
AF GASSE, F
   ARNOLD, M
   FONTES, JC
   FORT, M
   GIBERT, E
   HUC, A
   LI, BY
   LI, YF
   LJU, Q
   MELIERES, F
   VANCAMPO, E
   WANG, FB
   ZHANG, QS
TI A 13,000-YEAR CLIMATE RECORD FROM WESTERN TIBET
SO NATURE
LA English
DT Article
ID holocene; circulation; transition; sahara; china; lake
AB ALTHOUGH the Tibetan plateau is important in influencing the atmospheric circulation of the Northern Hemisphere 1-3, there are only a few continuous palaeoclimate records available, and these are limited to the plateau's northeastern margin 4-6. Here we present a 13,000-yr record from Sumxi Co (western Tibet), constructed from both lake-core and shoreline studies, which shows that conditions in the early-middle Holocene were warmer and wetter than at present. These results confirm model predictions of an intensified monsoon over the region at approximately 9,000 yr BP, owing to an orbitally induced increase in summer insolation 7,8. We also find evidence for warm, humid pulses at approximately 12,500 and approximately 10,000 yr BP, in phase with the steps of the last deglaciation, and for a. return to cold, dry conditions at approximately 11-10,000 yr BP, none of which can be explained by orbital variations. The existence of the cold episode confirms that the cooling associated with the Younger Dryas event occurred in continental China 6,9, and provides further evidence of the global nature of this event 10.
C1 CEA, CTR FAIBLES RADIOACT, CNRS, F-91198 GIF SUR YVETTE, FRANCE.
   UNIV PARIS 07, GEOG PHYS LAB, F-75251 PARIS 05, FRANCE.
   INST FRANCAIS PETR, F-92506 RUEIL MALMAISON, FRANCE.
   CHINESE ACAD SCI, INST GEOG, BEIJING 100012, PEOPLES R CHINA.
   MUSEUM NATL HIST NAT, GEOL LAB, F-75231 PARIS 05, FRANCE.
   FAC SCI LUMINY, GEOL QUATERNAIRE LAB, F-13288 MARSEILLE 2, FRANCE.
   NANJING UNIV, DEPT GEOG, NANJING, PEOPLES R CHINA.
C3 Universite Paris Saclay; CEA; Centre National de la Recherche Scientifique (CNRS); Universite Paris Cite; IFP Energies Nouvelles; Chinese Academy of Sciences; Museum National d'Histoire Naturelle (MNHN); Aix-Marseille Universite; Nanjing University
RP GASSE, F (corresponding author), UNIV PARIS 11, HYDROL & GEOCHIM ISOTOPIQUE LAB, BATIMENT 504, F-91405 ORSAY, FRANCE.
NR 31
TC 517
Z9 675
U1 4
U2 144
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 742
EP 745
DI 10.1038/353742a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600064
DA 2026-03-10
ER

PT J
AU KELLEY, J
   XU, QH
AF KELLEY, J
   XU, QH
TI EXTREME SEXUAL DIMORPHISM IN A MIOCENE HOMINOID
SO NATURE
LA English
DT Article
ID body size; evolution; variability; monkeys; china
AB SOME Miocene hominoids may have been extremely sexually dimorphic for body size, inferred from the apparent dimorphism of dental and gnathic remains 1-4.  But this has never been demonstrated convincingly for any fossil species because of small sample sizes, uncertainties about the number of species in most fossil samples, and the inability to reliably sex individual specimens.  Here we demonstrate a case of extreme dental dimorphism, and presumed body-size dimorphism, in a Miocene hominoid sample in which these limitations have been overcome.  Lufengpithecus lufengensis from the late Miocene site of Lufeng, China, was more dimorphic than the most dimorphic living hominoid, the orangutan, and may have been more dimorphic than any living anthropoid.
C1 BROWN UNIV,DIV BIOL & MED,PROVIDENCE,RI 02912.
   ACAD SINICA,INST VERTEBRATE PALEONTOL & PALEOANTHROPOL,BEIJING 100044,PEOPLES R CHINA.
C3 Brown University; Chinese Academy of Sciences; Institute of Vertebrate Paleontology & Paleoanthropology, CAS
NR 33
TC 49
Z9 54
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 151
EP 153
DI 10.1038/352151a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700054
PM 1906139
DA 2026-03-10
ER

PT J
AU CUMMING, BG
   JOHNSTON, EB
   PARKER, AJ
AF CUMMING, BG
   JOHNSTON, EB
   PARKER, AJ
TI VERTICAL DISPARITIES AND PERCEPTION OF 3-DIMENSIONAL SHAPE
SO NATURE
LA English
DT Article
ID depth; distance
AB THE information about depth and three-dimensional shape available from the horizontal component of the stereo disparity field requires interpretation in conjunction with information about ego-centric viewing distance (D).  A novel computational approach for estimating D was proposed by Mayhew and Longuet-Higgins 1,2, who demonstrated that the horizontal gradient of vertical disparities uniquely specifies the viewing distance.  We have now used random dot stereograms in a shape judgement task to show that changes in vertical disparities have no effect on perceived three-dimensional shape.  Changes in ocular convergence do alter perceived shape, suggesting substantial changes in the subjects' scaling of horizontal disparities.  We conclude that vertical disparities are not used to scale disparities for viewing distance, and that extraretinal signals must be considered when analysing human three-dimensional shape perception.
RP CUMMING, BG (corresponding author), UNIV OXFORD,PHYSIOL LAB,PARKS RD,OXFORD OX1 3PT,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 11
TC 89
Z9 96
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 411
EP 413
DI 10.1038/349411a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400049
PM 1992341
DA 2026-03-10
ER

PT J
AU BAILLY, E
   MCCAFFREY, M
   TOUCHOT, N
   ZAHRAOUI, A
   GOUD, B
   BORNENS, M
AF BAILLY, E
   MCCAFFREY, M
   TOUCHOT, N
   ZAHRAOUI, A
   GOUD, B
   BORNENS, M
TI PHOSPHORYLATION OF 2 SMALL GTP-BINDING PROTEINS OF THE RAB FAMILY BY P34CDC2
SO NATURE
LA English
DT Article
ID vesicular stomatitis-virus; synthesized g-protein; control gene cdc2+; ypt1 protein; yeast; secretion; membrane; mitosis; product; activation
AB ENTRY of a cell into mitosis induces a series of structural and functional changes including arrest of intracellular transport 1-4.  Knowledge of how the mitotic cycle is driven progressed substantially with the identification of the p34cdc2 protein kinase as a subunit of maturation-promoting factor 5-7, the universal regulating component of the mitotic cycle 8.  Activation of the kinase at the onset of mitosis 9 is thought to trigger the important mitotic events by phosphorylating key proteins 10.  Small guanine nucleotide-binding proteins have been implicated in regulating transport pathways.  For instance, two small Ras-related GTP-binding proteins, Sec4p and Ypt1p, control distinct stages of the secretory pathway in budding yeast 11-15.  The GTP-binding proteins of the Rab family in rats and humans 16,17 display strong homologies with Sec4p and Ypt1p, and might therefore also be involved in regulating intracellular transport.  Indeed, distinct Rab proteins are located in the exocytotic and endocytotic compartments 18-21.  Interruption of vesicular transport during mitosis might involve modification of these proteins.  We now present biochemical evidence for a mitosis-specific p34cdc2 phosphorylation of Rab1Ap and Rab4p.  By contrast, Rab2p and Rab6p are not phosphorylated.  We also show that the distribution of Rab1Ap and Rab4p between cytosolic and membrane-bound forms is different in interphase and mitotic cells.  This may provide a clue to the mechanism by which phosphorylation could affect membrane traffic during mitosis.
C1 INST PASTEUR,CNRS,URA 361,UNITE GENET SOMAT,F-75724 PARIS,FRANCE.
   FAC MED LARIBOISIERE,INSERM,U248,F-75010 PARIS,FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS); Pasteur Network; Universite Paris Cite; Institut Pasteur Paris; Institut National de la Sante et de la Recherche Medicale (Inserm); Universite Paris Cite
RP BAILLY, E (corresponding author), CNRS,CTR GENET MOLEC,F-91198 GIF SUR YVETTE,FRANCE.
NR 34
TC 146
Z9 166
U1 0
U2 1
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 715
EP 718
DI 10.1038/350715a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000063
PM 1902553
DA 2026-03-10
ER

PT J
AU SCHLOTTERER, C
   AMOS, B
   TAUTZ, D
AF SCHLOTTERER, C
   AMOS, B
   TAUTZ, D
TI CONSERVATION OF POLYMORPHIC SIMPLE SEQUENCE LOCI IN CETACEAN SPECIES
SO NATURE
LA English
DT Article
ID dna; evolution
AB LENGTH polymorphisms within simple-sequence loci occur ubiquitously in non-coding eukaryotic DNA and can be highly informative in the analysis of natural populations 1-4. Simple-sequence length polymorphisms (SSLP) in the long-finned pilot whale Globicephala melas (Delphinidae) have provided useful information on the mating system as well as on the genetic structure of populations 5. We have therefore tested whether the polymerase chain reaction primers designed for Globicephala could also be used to uncover variability in other whale species. Homologous loci could indeed be amplified from a diverse range of whales, including all toothed (Odontoceti) and baleen whales (Mysticeti) tested. Cloning and sequencing these loci from 11 different species revealed an unusually high conservation of sequences flanking the simple-sequence stretches, averaging 3.2% difference over 35-40 Myr. This represents the lowest divergence rate for neutral nucleotide positions found for any species group so far and raises the possible need for a re-evaluation of the age of the modern whales. On the other hand, the high conservation of non-coding sequences in whales simplifies the application of SSLP DNA fingerprinting in cetacean species, as primers designed for one species will often uncover variability in other species.
C1 UNIV MUNICH,INST GENET,W-8000 MUNICH 19,GERMANY.
   UNIV CAMBRIDGE,DEPT GENET,CAMBRIDGE CB2 3EH,ENGLAND.
C3 University of Munich; University of Cambridge
NR 17
TC 304
Z9 350
U1 1
U2 39
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 63
EP 65
DI 10.1038/354063a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900058
PM 1944571
DA 2026-03-10
ER

PT J
AU LANGE, C
   JUGEL, A
   WALTER, J
   NOYERWEIDNER, M
   TRAUTNER, TA
AF LANGE, C
   JUGEL, A
   WALTER, J
   NOYERWEIDNER, M
   TRAUTNER, TA
TI PSEUDO DOMAINS IN PHAGE-ENCODED DNA METHYLTRANSFERASES
SO NATURE
LA English
DT Article
ID target-recognizing domains; bacillus-subtilis phages; sequence; organization; restriction; motifs; spr
AB 5-Cytosine-DNA-methyltransferases, which are found in many organisms ranging from bacteriophages to mammals, transfer a methyl group from S-adenosylmethionine to the carbon-5 of a cytosine residue in specific DNA target sequences 1. Some phage-encoded methyltransferases methylate more than one sequence:  these enzymes contain several independent target-recognizing domains each responsible for recognizing a different site. The amino-acid sequences of these multispecific methyltransferases reveal that some enzymes in addition carry domains that do not contribute to the enzymes' methylation potential, but strongly resemble previously identified target-recognizing domains. Here we show that introducing defined amino-acid alterations into these inactive domains endows these enzymes with additional methylation specificities. Gel retardation analysis demonstrates that these novel methylation specificities correlate with the acquisition of additional DNA-binding potential of the proteins.
RP LANGE, C (corresponding author), MAX PLANCK INST MOLEC GENET,IHNESTR 73,W-1000 BERLIN 33,GERMANY.
NR 16
TC 28
Z9 28
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 645
EP 648
DI 10.1038/352645a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100064
PM 1865925
DA 2026-03-10
ER

PT J
AU NAGY, B
   GAUTHIERLAFAYE, F
   HOLLIGER, P
   DAVIS, DW
   MOSSMAN, DJ
   LEVENTHAL, JS
   RIGALI, MJ
   PARNELL, J
AF NAGY, B
   GAUTHIERLAFAYE, F
   HOLLIGER, P
   DAVIS, DW
   MOSSMAN, DJ
   LEVENTHAL, JS
   RIGALI, MJ
   PARNELL, J
TI ORGANIC-MATTER AND CONTAINMENT OF URANIUM AND FISSIOGENIC ISOTOPES AT THE OKLO NATURAL REACTORS
SO NATURE
LA English
DT Article
ID deposits; gabon; age
AB SOME of the Precambrian natural fission reactors at Oklo in Gabon contain abundant organic matter 1,2, part of which was liquefied at the time of criticality and subsequently converted to a graphitic solid 3,4 . The liquid organic matter helps to reduce U(VI) to U(IV) from aqueous solutions, resulting in the precipitation of uraninite 5. It is known that in the prevailing reactor environments, precipitated uraninite grains incorporated fission products. We report here observations which show that these uraninite crystals were held immobile within the re-solidified, graphitic bitumen. Unlike water-soluble (humic) organic matter, the graphitic bituminous organics at Oklo thus enhanced radionuclide containment. Uraninite encased in solid graphitic matter in the organic-rich reactor zones lost virtually no fissiogenic lanthanide isotopes. The first major episode of uranium and lead migration was caused by the intrusion of a swarm of adjacent dolerite dykes about 1,100 Myr after the reactors went critical. Our results from Oklo imply that the use of organic, hydrophobic solids such as graphitic bitumen as a means of immobilizing radionuclides in pretreated nuclear waste warrants further investigation.
C1 CNRS,CTR GEOCHIM SURFACE,F-67084 STRASBOURG,FRANCE.
   US GEOL SURVEY,DENVER FED CTR,DENVER,CO 80225.
   QUEENS UNIV BELFAST,DEPT GEOL,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND.
   CEN,F-38041 GRENOBLE,FRANCE.
   ROYAL ONTARIO MUSEUM,DEPT GEOL,TORONTO M5S 2C6,ONTARIO,CANADA.
   MT ALLISON UNIV,DEPT GEOL,SACKVILLE E0A 3C0,NB,CANADA.
C3 Centre National de la Recherche Scientifique (CNRS); Universites de Strasbourg Etablissements Associes; Universite de Strasbourg; United States Department of the Interior; United States Geological Survey; Queens University Belfast; Royal Ontario Museum; Mount Allison University
RP NAGY, B (corresponding author), UNIV ARIZONA,DEPT GEOSCI,ORGAN GEOCHEM LAB,TUCSON,AZ 85721, USA.
NR 28
TC 85
Z9 86
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 472
EP 475
DI 10.1038/354472a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800058
DA 2026-03-10
ER

PT J
AU HO, PTP
   HO, LC
   SZCZEPANSKI, JC
   JACKSON, JM
   ARMSTRONG, JT
   BARRETT, AH
AF HO, PTP
   HO, LC
   SZCZEPANSKI, JC
   JACKSON, JM
   ARMSTRONG, JT
   BARRETT, AH
TI A MOLECULAR GAS STREAMER FEEDING THE GALACTIC-CENTER
SO NATURE
LA English
DT Article
ID aperture synthesis observations; ionized-gas; a complex; sgr-a; environment; sagittarius; galaxy; cloud; disk
AB Radio maps of ammonia emission around the nucleus of the Milky Way reveal a long streamer of molecular gas connecting the well known circumnuclear 2-pc ring with molecular clouds 10-20 pc further out.  These clouds appear to be interacting with nearby supernova remnants, suggesting that the impact of the supernovae on the gas may have impelled some of it inwards, thus providing a source of fuel for the activity at the Galactic Centre.
C1 USN OBSERV,DEPT ASTRON,WASHINGTON,DC 20390.
   MIT,DEPT PHYS,CAMBRIDGE,MA 02139.
   BOSTON UNIV,DEPT ASTRON,BOSTON,MA 02215.
C3 United States Department of Defense; United States Navy; Massachusetts Institute of Technology (MIT); Boston University
RP HO, PTP (corresponding author), HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138, USA.
NR 16
TC 66
Z9 70
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 309
EP 312
DI 10.1038/350309a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800081
DA 2026-03-10
ER

PT J
AU CAVA, RJ
   BATLOGG, B
   KRAJEWSKI, JJ
   GAMMEL, P
   POULSEN, HF
   PECK, WF
   RUPP, LW
AF CAVA, RJ
   BATLOGG, B
   KRAJEWSKI, JJ
   GAMMEL, P
   POULSEN, HF
   PECK, WF
   RUPP, LW
TI ANTIFERROMAGNETISM AND METALLIC CONDUCTIVITY IN NB12O29
SO NATURE
LA English
DT Article
AB AT the heart of the controversy about the microscopic origin of superconductivity in high-transition-temperature copper oxide superconductors is the question of whether or not the antiferromagnetism associated with the single-hole Cu2+ 3d9 state is of fundamental importance.  To test whether this unconventional spin-mediated superconductivity might be electron/hole symmetric, oxides of the elements with single d-orbital electrons, such as Ti3+ (3d1), Nb4+ (4d1) and W5+ (5d1), are of particular interest.  Localized magnetic spin states and magnetic ordering have never been observed previously in transition-metal oxides with one or two electrons in the 4d or 5d states, because of the preference for conventional d-band metallic conductivity or for metal-metal bonding.  In exploring the possibility of a d1-d9 and ferroelectricity-superconductivity relationship in oxides (see, for instance, ref. 1), we have found that Nb12O29, a material with a 'crystallographic shear' structure, displays simultaneously both metallic conductivity, a signature of delocalized electrons, and local-moment magnetism with an antiferromagnetic ordering temperature of 12 K.  This suggests that the bonding to oxygen of the 4d levels of early-transition-metal elements may not be sufficiently covalent to yield the kind of exotic conductivity (and thus exotic superconductivity) observed for copper oxides.
C1 RISO NATL LAB,DEPT PHYS,DK-4000 ROSKILDE,DENMARK.
C3 Technical University of Denmark
RP CAVA, RJ (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 12
TC 53
Z9 60
U1 0
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 598
EP 600
DI 10.1038/350598a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200055
DA 2026-03-10
ER

PT J
AU MURPHY, TJ
   ALEXANDER, RW
   GRIENDLING, KK
   RUNGE, MS
   BERNSTEIN, KE
AF MURPHY, TJ
   ALEXANDER, RW
   GRIENDLING, KK
   RUNGE, MS
   BERNSTEIN, KE
TI ISOLATION OF A CDNA-ENCODING THE VASCULAR TYPE-1 ANGIOTENSIN-II RECEPTOR
SO NATURE
LA English
DT Article
ID smooth-muscle cells; converting enzyme; molecular-cloning; system; expression; captopril; proteins; subtypes; calcium; family
AB ANGIOTENSIN II is an important effector molecule controlling blood pressure and volume in the cardiovascular system 1.  Its importance is manifested by the efficacy of angiotensin-converting enzyme inhibitors in the treatment of hypertension and congestive heart failure 2,3.  Angiotensin II interacts with two pharmacologically distinct subtypes of cell-surface receptors, AT1 and AT2 (ref. 4).  AT1 receptors seem to mediate the major cardiovascular effects of angiotensin II 5,6.  Here we report the isolation by expression cloning of a complementary DNA encoding a unique protein with the pharmacological specificity of a vascular AT1 receptor.  Hydropathic modelling of the deduced protein suggests that it shares the seven-transmembrane-region motif with the G protein-coupled receptor superfamily 7.  Knowledge of the AT1 receptor primary sequence should now permit structural analysis, definition of the angiotensin II receptor gene family and delineation of the contribution of AT receptors to the genetic component of hypertension.
C1 EMORY UNIV,SCH MED,DEPT MED,DIV CARDIOL,ATLANTA,GA 30322.
C3 Emory University
RP MURPHY, TJ (corresponding author), EMORY UNIV,SCH MED,DEPT PATHOL,ATLANTA,GA 30322, USA.
NR 31
TC 1261
Z9 1320
U1 0
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 233
EP 236
DI 10.1038/351233a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000057
PM 2041570
DA 2026-03-10
ER

PT J
AU HA, I
   LANE, WS
   REINBERG, D
AF HA, I
   LANE, WS
   REINBERG, D
TI CLONING OF A HUMAN GENE ENCODING THE GENERAL TRANSCRIPTION INITIATION FACTOR-IIB
SO NATURE
LA English
DT Article
ID rna polymerase-ii; adenovirus major late; nucleotide-sequence; sigma-factors; functional-analysis; escherichia-coli; dna; purification; activation; binding
AB Transcription factor IIB (TFIIB) has a central role in transcription of class II genes. The purification of the human TFIIB protein and isolation of a complementary DNA encoding TFIIB activity is reported here. The sequence of TFIIB, which seems to be encoded by a single gene, contains a repeated motif, in addition to a motif with similarity to the prokaryotic sigma-factors. The recombinant protein expressed in bacteria substituted for all the functions attributed to the human TFIIB protein.
C1 UNIV MED & DENT NEW JERSEY,ROBERT WOOD JOHNSON MED SCH,DEPT BIOCHEM,675 HOES LANE,PISCATAWAY,NJ 08854.
   HARVARD UNIV,HARVARD MICROCHEM FACIL,CAMBRIDGE,MA 02138.
C3 Rutgers University System; Rutgers University New Brunswick; Rutgers University Biomedical & Health Sciences; Harvard University
NR 51
TC 250
Z9 269
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 689
EP 695
DI 10.1038/352689a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400048
PM 1876184
DA 2026-03-10
ER

PT J
AU VENKITARAMAN, AR
   WILLIAMS, GT
   DARIAVACH, P
   NEUBERGER, MS
AF VENKITARAMAN, AR
   WILLIAMS, GT
   DARIAVACH, P
   NEUBERGER, MS
TI THE B-CELL ANTIGEN RECEPTOR OF THE 5 IMMUNOGLOBULIN CLASSES
SO NATURE
LA English
DT Article
ID murine lymphocytes-b; surface igm; molecular-components; antibody; complex; expression; transport; tolerance; secretion; proteins
AB Several proteins associate with surface IgM to form the antigen receptor.  We show that just two, the alpha and beta associated chains, are sufficient to reconstitute an IgM surface receptor in fibroblasts.  Contrary to expectation, a common alpha-chain associates with all five immunoglobulin classes.  We propose that B-cell antigen receptors consist of a common alpha/beta heterodimer associated with each immunoglobulin class.  But the classes differ both in the glycosylation of their associated alpha-chain and in their dependence on alpha/beta for surface transport.
C1 UNIV MONTPELLIER 2,IMMUNOGENET MOLEC LAB,F-34060 MONTPELLIER,FRANCE.
C3 Universite de Montpellier
RP VENKITARAMAN, AR (corresponding author), MRC,MOLEC BIOL LAB,HILLS RD,CAMBRIDGE CB2 2QH,ENGLAND.
NR 32
TC 281
Z9 302
U1 1
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 777
EP 781
DI 10.1038/352777a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400049
PM 1881434
DA 2026-03-10
ER

PT J
AU ESTERMANN, M
   MCCUSKER, LB
   BAERLOCHER, C
   MERROUCHE, A
   KESSLER, H
AF ESTERMANN, M
   MCCUSKER, LB
   BAERLOCHER, C
   MERROUCHE, A
   KESSLER, H
TI A SYNTHETIC GALLOPHOSPHATE MOLECULAR-SIEVE WITH A 20-TETRAHEDRAL-ATOM PORE OPENING
SO NATURE
LA English
DT Article
ID framework topology; phosphate
AB THE most widely used catalyst in petroleum cracking and reforming processes is the synthetic zeolite Y. Its unique properties arise from the fact that the enormous inner surface area created by the three-dimensional channel system is accessible to sorbed molecules through 12-ring pore openings. These windows, with free diameters of 7-8 angstrom, allow both aliphatic and small aromatic molecules to enter the zeolite. Attempts to synthesize zeolitic structures with even wider pores, to accommodate larger molecules, have produced two aluminophosphates with one-dimensional channels:  VPI-5 (ref. 1), which has 18-ring channels with free diameters of 12-13 angstrom, and AIPO4-8 (refs 2, 3), with oval 14-ring channels. We now report the structure of a new cubic gallophosphate with a pore opening comprising 20 tetrahedrally coordinated atoms in the shape of a four-leafed clover (Fig. 1) and a three-dimensional channel system. The unusual shape of the window is due to the presence of terminal hydroxyl groups in the framework, and provides new possibilities for shape-selective sorption. The supercage formed at the intersection of the channels has a body diagonal of 29-30 angstrom, and could thus accommodate larger intermediates in zeolite catalytic processes.
C1 ECOLE NATL SUPER CHIM,MAT MINERAUX LAB,CNRS,URA 428,F-68093 MULHOUSE,FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS)
RP ESTERMANN, M (corresponding author), SWISS FED INST TECHNOL,INST CRYSTALLOG,CH-8092 ZURICH,SWITZERLAND.
NR 20
TC 740
Z9 787
U1 2
U2 100
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 320
EP 323
DI 10.1038/352320a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900065
DA 2026-03-10
ER

PT J
AU HOFMANN, DJ
   DESHLER, T
AF HOFMANN, DJ
   DESHLER, T
TI EVIDENCE FROM BALLOON MEASUREMENTS FOR CHEMICAL DEPLETION OF STRATOSPHERIC OZONE IN THE ARCTIC WINTER OF 1989-90
SO NATURE
LA English
DT Article
ID clouds
AB Measurements of the vertical ozone profile with balloon-borne sensors in the Arctic during January and February 1990 indicate repeated minima in the 22-km region.  A general negative correlation of the 22-km ozone mixing ratio with time spent by the air parcel in regions cold enough for the formation of polar stratospheric clouds, together with the presence of sunlight on a portion of the air-parcel trajectory, and an inability to explain the ozone minimum by conventional dynamical processes, suggest that this feature is related to chemical ozone depletion.
RP HOFMANN, DJ (corresponding author), UNIV WYOMING,DEPT PHYS & ASTRON,LARAMIE,WY 82071, USA.
NR 14
TC 65
Z9 66
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 300
EP 305
DI 10.1038/349300a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100042
DA 2026-03-10
ER

PT J
AU HADDON, RC
   HEBARD, AF
   ROSSEINSKY, MJ
   MURPHY, DW
   DUCLOS, SJ
   LYONS, KB
   MILLER, B
   ROSAMILIA, JM
   FLEMING, RM
   KORTAN, AR
   GLARUM, SH
   MAKHIJA, AV
   MULLER, AJ
   EICK, RH
   ZAHURAK, SM
   TYCKO, R
   DABBAGH, G
   THIEL, FA
AF HADDON, RC
   HEBARD, AF
   ROSSEINSKY, MJ
   MURPHY, DW
   DUCLOS, SJ
   LYONS, KB
   MILLER, B
   ROSAMILIA, JM
   FLEMING, RM
   KORTAN, AR
   GLARUM, SH
   MAKHIJA, AV
   MULLER, AJ
   EICK, RH
   ZAHURAK, SM
   TYCKO, R
   DABBAGH, G
   THIEL, FA
TI CONDUCTING FILMS OF C60 AND C70 BY ALKALI-METAL DOPING
SO NATURE
LA English
DT Article
ID c-60
AB THE recent syntheses 1, 2 of macroscopic quantities of C60 have suggested possible applications in host-guest and organic chemistry, tribology, electrochemistry and semiconductor technology.  Here we report the preparation of alkali-metal-doped films of C60 and C70 which have electrical conductivities at room temperature that are comparable to those attained by n-type doped polyacetylene.  The highest conductivities observed in the doped films are:  4 S cm-1 (Cs/C60), 100 (Rb/C60), 500 (K/C60), 20 (Na/C60), 10 (Li/C60), 2 (K/C70).  The doping process is reversed on exposure of the films to the atmosphere.  At high doping levels, the films become more resistive.  We attribute the conductivity induced in these films to the formation of energy bands from the pi-orbitals of C60 or C70, which become partially filled with carriers on doping.  The smaller alkali metal ions should be able to fit into the interstices in the lattice without disrupting the network of contacts between the carbon spheroids.  In the case of C60, this would allow the development of an isotropic band structure, and we therefore propose that these materials may constitute the first three-dimensional 'organic' conductors.
RP HADDON, RC (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 10
TC 988
Z9 1053
U1 4
U2 219
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 320
EP 322
DI 10.1038/350320a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800084
DA 2026-03-10
ER

PT J
AU CHISHOLM, MF
   PENNYCOOK, SJ
AF CHISHOLM, MF
   PENNYCOOK, SJ
TI STRUCTURAL ORIGIN OF REDUCED CRITICAL CURRENTS AT YBA2CU3O7-DELTA GRAIN-BOUNDARIES
SO NATURE
LA English
DT Article
ID superconductors; oxygen
AB THE critical current density across individual grain boundaries in thin films of the high-T(c) superconductor YBa2Cu3O7-delta (YBCO) has been found 1-4 to be inversely proportional to lattice misorientation for tilts up to approximately 10-degrees.  Reports of impurity segregation 5,6 at grain boundaries, and variations in the chemical stoichiometry 7,8, have led to the view that deviations from the ideal composition are responsible for the depressed superconducting order parameter at the boundary.  Here we present images of YBCO grain boundaries obtained by a scanning transmission electron microscope in Z-contrast mode 9,10, which show that chemical segregation does not necessarily occur at these boundaries.  A simple model of the strain associated with the grain-boundary dislocations provides a reasonable physical explanation of the suppressed superconductivity.  The surprisingly large effect of strain implied by our model has implications beyond critical currents, for the physics and applications of any thin-film YBCO structures involving strained epitaxial layers.
RP CHISHOLM, MF (corresponding author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA.
NR 23
TC 198
Z9 203
U1 2
U2 79
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 47
EP 49
DI 10.1038/351047a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300053
DA 2026-03-10
ER

PT J
AU DIXON, AE
   DAMASKINOS, S
   ATKINSON, MR
AF DIXON, AE
   DAMASKINOS, S
   ATKINSON, MR
TI A SCANNING CONFOCAL MICROSCOPE FOR TRANSMISSION AND REFLECTION IMAGING
SO NATURE
LA English
DT Article
AB IN a confocal scanning laser microscope 1,2 (CSLM), the detector pinhole is confocal with the illuminated spot on the sample, and rejects light reflected from objects that are not in the focal plane.  This results in images that contain only sharp or empty areas, as opposed to non-confocal images which contain sharp and blurry areas, and allows the CSLM to perform optical sectioning.  Individual optical sections can be used to produce a true three-dimensional image or can be added together to produce an extended-depth-of-focus image.  For biological specimens, the intensity of the reflected-light (or fluorescence) signal decreases with increasing penetration into the sample, and self-shadowing also limits the information in the image.  Moreover, many biological specimens are only weak reflectors, but produce transmission images with good contrast.  The only confocal transmission images reported previously have used scanning-stage microscopes 3,4, although Goldstein 5 has reported a confocal scanning-beam microscope that should in principle work in transmission.  Here we describe a microscope that produces true confocal images in transmission, and also forms a reflected-light image from both the top and bottom of the specimen.  The optical slices produced in transmission do not change in average intensity with depth in the specimen, and as the microscope can also examine the specimen from the bottom in reflected light, loss of data by self-shadowing is minimized.  All of the original contrast modes of the CSLM (reflected light, fluorescence, differential phase contrast and so on) are also available using this new microscope.
RP DIXON, AE (corresponding author), UNIV WATERLOO,GUELPH WATERLOO PROGRAM GRAD WORK PHYS,WATERLOO CAMPUS,WATERLOO N2L 3G1,ONTARIO,CANADA.
NR 5
TC 43
Z9 47
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 551
EP 553
DI 10.1038/351551a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400052
DA 2026-03-10
ER

PT J
AU MASLEN, CL
   CORSON, GM
   MADDOX, BK
   GLANVILLE, RW
   SAKAI, LY
AF MASLEN, CL
   CORSON, GM
   MADDOX, BK
   GLANVILLE, RW
   SAKAI, LY
TI PARTIAL SEQUENCE OF A CANDIDATE GENE FOR THE MARFAN-SYNDROME
SO NATURE
LA English
DT Article
ID microfibrils; fibrillin; component; proteins; complex
AB FIBRILLIN is a large (relative molecular mass 350,000) glycoprotein which can be isolated from fibroblast cell cultures and is a component of the microfibrils that are ubiquitous in the connective tissue space 1.  The microfibrils of the suspensory ligament of the lens as well as the elastic fibre microfibrils of the blood vessel wall are composed of fibrillin. The ocular and cardiovascular manifestations of the Marfan syndrome are consistent with a defect in the gene coding for a structural constituent of these connective tissues. Immunohistological experiments have recently implicated fibrillin microfibrils in the pathogenesis of the Marfan syndrome 2. Genetic linkage data 3,4 localizing the Marfan gene to chromosome 15 and the in situ hybridization of fibrillin complementary DNA to 15q21.1 (ref. 5) together support fibrillin as a candidate Marfan gene. As a first step towards investigating the function of fibrillin in the architecture and development of connective tissues and its relationship to the Marfan syndrome, we report the cloning and partial sequencing of fibrillin cDNA.
C1 SHRINERS HOSP CRIPPLED CHILDREN,3101 SW SAM JACKSON PK RD,PORTLAND,OR 97201.
   OREGON HLTH SCI UNIV,DEPT BIOCHEM & MOLEC BIOL,PORTLAND,OR 97201.
C3 Oregon Health & Science University
NR 14
TC 299
Z9 325
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 334
EP 337
DI 10.1038/352334a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900070
PM 1852207
DA 2026-03-10
ER

PT J
AU ZAHLER, AM
   WILLIAMSON, JR
   CECH, TR
   PRESCOTT, DM
AF ZAHLER, AM
   WILLIAMSON, JR
   CECH, TR
   PRESCOTT, DM
TI INHIBITION OF TELOMERASE BY G-QUARTET DNA STRUCTURES
SO NATURE
LA English
DT Article
ID terminal transferase-activity; tetrahymena; ribonucleoprotein; oxytricha; repeats; enzyme; model
AB THE ends or telomeres of the linear chromosomes of eukaryotes are composed of tandem repeats of short DNA sequences, one strand being rich in guanine (G strand) and the complementary strand in cytosine 1,2.  Telomere synthesis involves the addition of telomeric repeats to the G strand by telomere terminal transferase (telomerase) 3-6. Telomeric G-strand DNAs from a variety of organisms adopt compact structures 7, the most stable of which is explained by the formation of G-quartets 8,9.  Here we investigate the capacity of the different folded forms of telomeric DNA to serve as primers for the Oxytricha nova telomerase in vitro.  Formation of the K+-stabilized G-quartet structure in a primer inhibits its use by telomerase.  Furthermore, the octanucleotide T4G4, which does not fold, is a better primer than (T4G4)2, which can form a foldback structure 7-10.  We conclude that telomerase does not require any folding of its DNA primer.  Folding of telomeric DNA into G-quartet structures seems to influence the extent of telomere elongation in vitro and might therefore act as a negative regulator of elongation in vivo.
C1 UNIV COLORADO,HOWARD HUGHES MED INST,DEPT CHEM & BIOCHEM,DEPT MOLEC CELLULAR & DEV BIOL,BOULDER,CO 80309.
C3 University of Colorado System; University of Colorado Boulder; Howard Hughes Medical Institute
NR 21
TC 1065
Z9 1240
U1 0
U2 163
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 718
EP 720
DI 10.1038/350718a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000064
PM 2023635
DA 2026-03-10
ER

PT J
AU BROWN, CJ
   LAFRENIERE, RG
   POWERS, VE
   SEBASTIO, G
   BALLABIO, A
   PETTIGREW, AL
   LEDBETTER, DH
   LEVY, E
   CRAIG, IW
   WILLARD, HF
AF BROWN, CJ
   LAFRENIERE, RG
   POWERS, VE
   SEBASTIO, G
   BALLABIO, A
   PETTIGREW, AL
   LEDBETTER, DH
   LEVY, E
   CRAIG, IW
   WILLARD, HF
TI LOCALIZATION OF THE X-INACTIVATION CENTER ON THE HUMAN X-CHROMOSOME IN XQ13
SO NATURE
LA English
DT Article
ID dna-polymerase-alpha; regional localization; gene; mouse; translocation
AB X-CHROMOSOME inactivation results in the strictly cis-limited inactivation of many but not all genes on one of the two X chromosomes during early development in somatic cells of mammalian females1.  One feature of virtually all models of X inactivation is the existence of an X-inactivation centre (XIC) required in cis for inactivation to occur2-5.  This concept predicts that all structurally abnormal X chromosomes capable of being inactivated have in common a defineable region of the X chromosome6-8.  Here we report an analysis of several such rearranged human X chromosomes and define a minimal region of overlap.  The results are consistent with models invoking a single XIC and provide a molecular foothold for cloning and analysing the XIC region.  One of the markers that defines this region is the XIST gene9, which is expressed specifically from inactive, but not active, X chromosomes.  The localization of the XIST gene to the XIC region on the human X chromosome implicates XIST in some aspect of X inactivation.
C1 STANFORD UNIV,MED CTR,SCH MED,DEPT GENET,STANFORD,CA 94305.
   NAPLES UNIV,FAC MED 2,DEPT PEDIAT,I-80138 NAPLES,ITALY.
   BAYLOR UNIV,INST MOLEC GENET,HOUSTON,TX 77030.
   UNIV OXFORD,GENET LAB,OXFORD OX3 9DU,ENGLAND.
C3 Stanford University; University of Naples Federico II; Baylor University; Baylor College of Medicine; University of Oxford
NR 33
TC 172
Z9 200
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 82
EP 84
DI 10.1038/349082a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100058
DA 2026-03-10
ER

PT J
AU GOODE, PR
   DZIEMBOWSKI, WA
AF GOODE, PR
   DZIEMBOWSKI, WA
TI SOLAR-CYCLE DEPENDENCE OF THE SUNS DEEP INTERNAL-ROTATION SHOWN BY HELIOSEISMOLOGY
SO NATURE
LA English
DT Article
AB HELIOSEISMOLOGY, the study of solar oscillations, yields information on the Sun's internal rotation and magnetism which is of great importance in understanding the 22-year solar cycle.  We show here that helioseismic data suggest that the Sun's internal rotation rate, at depths greater than half the solar radius, has changed systematically during the most recent cycle.  There is no variation, however, in greater the rotation over a range of intermediate solar radii covering the upper part of the Sun's radiative interior and the lower part of the convective zone; this intermediate region is where, according to the same helioseismic data, an abrupt change in rotation rate with depth accompanies the transition from convective to radiative structure.  We suggest that the modulation of the rotation rate in the Sun's interior could be caused by a torsional oscillation, provided that a poloidal magnetic field of kilogauss strength exists in the radiative interior.
C1 NEW JERSEY INST TECHNOL,DEPT PHYS,NEWARK,NJ 07102.
   POLISH ACAD SCI,COPERNICUS ASTRON CTR,WARSAW 42,POLAND.
   UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106.
C3 New Jersey Institute of Technology; Polish Academy of Sciences; University of California System; University of California Santa Barbara
NR 15
TC 27
Z9 27
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 223
EP 225
DI 10.1038/349223a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900048
DA 2026-03-10
ER

PT J
AU MANDRUS, D
   FORRO, L
   KOLLER, D
   MIHALY, L
AF MANDRUS, D
   FORRO, L
   KOLLER, D
   MIHALY, L
TI GIANT TUNNELING ANISOTROPY IN THE HIGH-TC SUPERCONDUCTOR BI2SR2CACU2O8
SO NATURE
LA English
DT Article
ID electron-tunneling experiments; ca-cu-o; energy-gap; single-crystals; conductance; junctions
AB TUNNELLING spectroscopy has been one of the most fruitful methods in the study of superconductors 1,2. Excellent agreement has been obtained between theory and experiment, and even the fine details of the tunnelling spectra for conventional, low-transition-temperature (low-T(c)) superconductors have been explained in terms of electron-phonon interactions. The low-T(c) materials are generally isotropic enough for accurate measurements to be made on polycrystalline specimens; in contrast, it has been difficult to obtain reliable and reproducible tunnelling data for the highly anisotropic high-T(c) materials 3. We have overcome these difficulties by performing break-junction tunnelling measurements 4 on extremely thin single crystals, and show here that the tunnelling spectra of Bi2Sr2CaCu2O8 are indeed highly anisotropic. In the superconducting state, for electrons tunnelling parallel to the copper oxide planes, there are no electronic states at the Fermi level. In the normal state the tunnelling conductance is nearly independent of the d.c. bias voltage. Tunnelling perpendicular to the copper oxide planes was found to be qualitatively different from that parallel to the planes, and we suggest that electron scattering processes play an important role here.
C1 UNIV ZAGREB, INST PHYS, YU-41001 ZAGREB, CROATIA.
C3 University of Zagreb; Institute of Physics Zagreb
RP MANDRUS, D (corresponding author), SUNY STONY BROOK, DEPT PHYS, STONY BROOK, NY 11794 USA.
NR 28
TC 138
Z9 138
U1 0
U2 14
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 460
EP 462
DI 10.1038/351460a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800047
DA 2026-03-10
ER

PT J
AU PEASE, RJ
   HARRISON, GB
   SCOTT, J
AF PEASE, RJ
   HARRISON, GB
   SCOTT, J
TI COTRANSLOCATIONAL INSERTION OF APOLIPOPROTEIN-B INTO THE INNER LEAFLET OF THE ENDOPLASMIC-RETICULUM
SO NATURE
LA English
DT Article
ID protein translocation; microsomal-membranes; translation system; stop-transfer; sequence; coronavirus; fractions; invitro
AB APOLIPOPROTEIN (apo) B100 is required for the distribution of hepatic triglyceride to peripheral tissues as very-low-density lipoproteins.  The translocation of apo B100 into the endoplasmic reticulum (ER) and its subsequent assembly into lipoprotein particles is of particular interest as the protein is both very large (relative molecular mass 512,000) and insoluble in water.  It has been proposed that apo B translocation occurs in discrete stages and is completed post-translationally 1.  Several sites of arrest of translocation were reported to be present in apo B15 (the N-terminal 15% of the protein).  We have re-examined this question by in vitro translation coupled with translocation into microsomes, and find no evidence for transmembrane segments in truncated apo B proteins.  Translocated apo B17 is strongly associated with the membrane of the ER, being only partially releasable with alkaline carbonate, and remaining bound to the microsomes following disruption with saponin.  The efficient binding of short segments of apo B, despite the absence of transmembrane domains, suggests that apo B is cotranslationally inserted into the inner leaflet of the ER.  This will obviate problems caused by the size and insolubility of apo B100, because the growing hydrophobic protein chains will never exist in a lipid-free form during translocation.  From the inner leaflet, apo B in association with membrane-derived lipid can bud into the lumen of the ER to form nascent lipoprotein particles.
RP PEASE, RJ (corresponding author), MRC,CLIN RES CTR,DIV MOLEC MED,WATFORD RD,HARROW HA1 3UJ,MIDDX,ENGLAND.
NR 20
TC 78
Z9 84
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 448
EP 450
DI 10.1038/353448a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600063
PM 1896087
DA 2026-03-10
ER

PT J
AU KIM, J
   CHEONG, C
   MOORE, PB
AF KIM, J
   CHEONG, C
   MOORE, PB
TI TETRAMERIZATION OF AN RNA OLIGONUCLEOTIDE CONTAINING A GGGG SEQUENCE
SO NATURE
LA English
DT Article
ID 5'-guanosine monophosphate; fiber diffraction; telomeric dna; x-ray; model; acid
AB POLY rG can form four-stranded helices 1. The Hoogsteen-paired quartets of G residues on which such structures depend are so stable that they will form in 5'-GMP solutions, provided that Na+ or K+ are present (see for example, refs 2-4). Telomeric DNA sequences, which are G-rich, adopt four-stranded antiparallel G-quartet conformations in vitro 5,6, and parallel tetramerization of G-rich sequences may be involved in meiosis 7,8. Here we show that RNAs containing short runs of Gs can also tetramerize. A 19-base oligonucleotide derived from the 5S RNA of Escherichia coli (strand III), 5'GCCGAUGGUAGUGUGGGGU3', forms a K+-stabilized tetrameric aggregate that depends on the G residues at its 3' end. This complex is so stable that it would be surprising if similar structures do not occur in nature.
RP KIM, J (corresponding author), YALE UNIV, DEPT CHEM, 225 PROSPECT ST, NEW HAVEN, CT 06511 USA.
NR 12
TC 147
Z9 165
U1 0
U2 15
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 331
EP 332
DI 10.1038/351331a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600066
PM 1709723
DA 2026-03-10
ER

PT J
AU RIORDAN, ML
   MARTIN, JC
AF RIORDAN, ML
   MARTIN, JC
TI OLIGONUCLEOTIDE-BASED THERAPEUTICS
SO NATURE
LA English
DT Article
ID triple helix formation; inhibition; rna; dna
AB Oligonucleotide analogues offer several mechanisms for potential therapeutic action; triple helix agents that inhibit disease-causing genes at the DNA level show particular promise.
RP RIORDAN, ML (corresponding author), GILEAD SCI,346 LAKESIDE DR,FOSTER CITY,CA 94404, USA.
NR 14
TC 62
Z9 80
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 442
EP 443
DI 10.1038/350442a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200057
DA 2026-03-10
ER

PT J
AU HADDON, RC
   SCHNEEMEYER, LF
   WASZCZAK, JV
   GLARUM, SH
   TYCKO, R
   DABBAGH, G
   KORTAN, AR
   MULLER, AJ
   MUJSCE, AM
   ROSSEINSKY, MJ
   ZAHURAK, SM
   MAKHIJA, AV
   THIEL, FA
   RAGHAVACHARI, K
   COCKAYNE, E
   ELSER, V
AF HADDON, RC
   SCHNEEMEYER, LF
   WASZCZAK, JV
   GLARUM, SH
   TYCKO, R
   DABBAGH, G
   KORTAN, AR
   MULLER, AJ
   MUJSCE, AM
   ROSSEINSKY, MJ
   ZAHURAK, SM
   MAKHIJA, AV
   THIEL, FA
   RAGHAVACHARI, K
   COCKAYNE, E
   ELSER, V
TI EXPERIMENTAL AND THEORETICAL DETERMINATION OF THE MAGNETIC-SUSCEPTIBILITY OF C60 AND C70
SO NATURE
LA English
DT Article
ID aromatic character; icosahedral c-60; annulenes
AB THE magnetic susceptibility of C60 and the possibility of magnetic-field-induced pi-electron ring currents in this carbon spheroid have been of interest since the initial experiments on carbon clusters 1.  If the molecule is regarded as a sphere with a radius of 3.5 angstrom, on which 60 electrons are free to move, the Pauling ring-current model predicts a ring-current diamagnetic susceptibility 41 times the pi-electron ring-current magnetic susceptibility of benzene with the field normal to the plane of the six-membered ring 2,3.  London theory predicts, however, that the pi-electron ring currents in C60 should be weakly paramagnetic or diamagnetic, depending on the relative bond strengths used in the calculation 2,3.  With the availability of macroscopic quantities of C60 (ref. 4), it is now possible to study experimentally the magnetic properties of the molecule.  Here we report on such measurements.  We find that the diamagnetism of C60 is small, a result that we attribute to excited-state paramagnetic contributions to the pi-electron ring-current magnetic susceptibility.  Thus C60 seems to be an aromatic molecule with a vanishingly small pi-electron ring-current magnetic susceptibility.  We have performed similar measurements on C70, which indicate an appreciable pi-electron diamagnetism, consistent with theoretical calculations.  We attribute the differences in magnetic properties of these two molecules to their different fractions of five-membered ring structures.  The fullerenes may thus constitute a class of compounds of 'ambiguous' aromatic character, traditional measures of which will not provide an adequate classification.
C1 CORNELL UNIV,DEPT PHYS,ITHACA,NY 14853.
C3 Cornell University
RP HADDON, RC (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 21
TC 171
Z9 176
U1 0
U2 43
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 46
EP 47
DI 10.1038/350046a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300058
DA 2026-03-10
ER

PT J
AU LEE, B
   GODFREY, M
   VITALE, E
   HORI, H
   MATTEI, MG
   SARFARAZI, M
   TSIPOURAS, P
   RAMIREZ, F
   HOLLISTER, DW
AF LEE, B
   GODFREY, M
   VITALE, E
   HORI, H
   MATTEI, MG
   SARFARAZI, M
   TSIPOURAS, P
   RAMIREZ, F
   HOLLISTER, DW
TI LINKAGE OF MARFAN-SYNDROME AND A PHENOTYPICALLY RELATED DISORDER TO 2 DIFFERENT FIBRILLIN GENES
SO NATURE
LA English
DT Article
ID abnormality; microfibrils; defect
AB MARFAN Syndrome (MFS), one of the most common genetic disorders of connective tissue, is characterized by skeletal, cardiovascular and ocular abnormalities 1.  The incidence of the disease is about 1 in 20,000, with life expectancy severely reduced because of cardiovascular complications. As the underlying defect is unknown, MFS diagnosis is based solely on clinical criteria. Certain phenotypic features of MFS are also shared by other conditions, which may be genetically distinct entities although part of a clinical continuum. Immunohistochemical studies have implicated fibrillin, a major component of elastin-associated microfibrils 2, in MFS aetiology 3,4.  Genetic linkage analysis with random probes has independently localized the MFS locus to chromosome 15 (refs 5-7). Here we report that these two experimental approaches converge with the cloning and mapping of the fibrillin gene to chromosome 15q15-21, and with the establishment of linkage to MFS. We also isolated a second fibrillin gene and mapped it to chromosome 5q23-31. We linked this novel gene to a condition, congenital contractural arachnodactyly, that shares some of the features of MFS 1.  Thus, the cosegregation of two related genes with two related syndromes implies that fibrillin mutations are likely to be responsible for different MFS phenotypes.
C1 CUNY MT SINAI SCH MED,BROOKDALE CTR MOLEC BIOL,1 GUSTAVE LEVY PL,NEW YORK,NY 10029.
   UNIV NEBRASKA,MED CTR,DEPT PEDIAT,MEYER REHABIL INST,MUNROE CTR HUMAN GENET,OMAHA,NE 68131.
   HOP ENFANTS LA TIMONE,INSERM,U242,F-13385 MARSEILLE,FRANCE.
   UNIV CONNECTICUT,CTR HLTH,DEPT PEDIAT,MOLEC GENET LAB,FARMINGTON,CT 06030.
   TOKYO MED & DENT UNIV,MED RES INST,DEPT TISSUE PHYSIOL,TOKYO 101,JAPAN.
   UNIV NEBRASKA,MED CTR,DEPT PATHOL,OMAHA,NE 68131.
C3 Icahn School of Medicine at Mount Sinai; City University of New York (CUNY) System; University of Nebraska System; University of Nebraska Medical Center; Institut National de la Sante et de la Recherche Medicale (Inserm); Aix-Marseille Universite; Assistance Publique-Hopitaux de Marseille; University of Connecticut; Institute of Science Tokyo; Tokyo Medical & Dental University (TMDU); University of Nebraska System; University of Nebraska Medical Center
NR 19
TC 590
Z9 644
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 330
EP 334
DI 10.1038/352330a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900069
PM 1852206
DA 2026-03-10
ER

PT J
AU SCHRAG, JD
   LI, Y
   WU, S
   CYGLER, M
AF SCHRAG, JD
   LI, Y
   WU, S
   CYGLER, M
TI SER-HIS-GLU TRIAD FORMS THE CATALYTIC SITE OF THE LIPASE FROM GEOTRICHUM-CANDIDUM
SO NATURE
LA English
DT Article
ID amino-acid-sequence; 2 molecular-forms; pancreatic lipase; cdna; mechanism; acetylcholinesterase; resolution; cutinase; cloning
AB THE Ser-His-Asp triad is a well known structural feature of the serine proteases. It has also been directly observed in the catalytic sites of two lipases, whose high-resolution three-dimensional structures have been determined 1,2. Lipases show a wide variety of sizes, substrate and positional specificities, and catalytic rates 3. They achieve maximal catalytic rates at oil-water interfaces. The fungus Geotrichum candidum produces several different forms of lipases, two of which have been purified to homogeneity 4,5. Two lipase genes have been identified, cloned and sequenced 6,7. Both code for proteins of 544 amino acids with a total relative molecular mass of about 60,000 (M(r) 60K). The two forms are 86% identical. Their isoelectric points differ slightly, being between 43 and 4.6. About 7% of the total M(r) is carbohydrate. Until now, only a low resolution structure of GCL has been reported 8, but no high resolution structure has followed. We now report the three-dimensional structure of a lipase from G. candidum (GCL) at 2.2 angstrom resolution. Unlike the other lipases and serine proteases, the catalytic triad of GCL is Ser-His-Glu, with glutamic acid replacing the usual aspartate. Although the sequence similarity with the other two lipases is limited to the region near the active-site serine, there is some similarity in their three-dimensional structures. The GCL is also an alpha/beta-protein with a central mixed beta-sheet whose topology is similar to that of the N-terminal domain of human pancreatic lipase. As in the other lipases 1,2, the catalytic site is buried under surface loops. Sequence comparisons with proteins from the cholinesterase family suggest that they also contain the Ser-His-Glu triad.
C1 NATL RES COUNCIL CANADA, BIOTECHNOL RES INST, MONTREAL H4P 2R2, QUEBEC, CANADA.
C3 National Research Council Canada
NR 29
TC 491
Z9 520
U1 1
U2 52
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 761
EP 764
DI 10.1038/351761a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100070
PM 2062369
DA 2026-03-10
ER

PT J
AU PACKER, C
   GILBERT, DA
   PUSEY, AE
   OBRIEN, SJ
AF PACKER, C
   GILBERT, DA
   PUSEY, AE
   OBRIEN, SJ
TI A MOLECULAR GENETIC-ANALYSIS OF KINSHIP AND COOPERATION IN AFRICAN LIONS
SO NATURE
LA English
DT Article
ID dna; relatedness; coalitions; paternity
AB AFRICAN lions live in complex social groups and show extensive cooperative behaviour 1-10.  Here we describe a new application of DNA fingerprinting that unequivocally demonstrates the kinship structure of lion 'prides':  female companions are always closely related, male companions are either closely related or unrelated, and mating partners are usually unrelated.  The variability in relatedness among male coalition partners provides an important opportunity to test for the effects of kinship on cooperative behaviour 11.  Paternity analysis reveals that male reproductive success becomes increasingly skewed as coalition size increases, and the tendency to form coalitions with non-relatives drops sharply with increasing coalition size.  Thus males only act as non-reproductive 'helpers' in coalitions composed of close relatives.
C1 WR GRACE & CO CONN,WASHINGTON RES CTR,DEPT BIOMOLEC RES,COLUMBIA,CT.
   NCI,FREDERICK CANC RES & DEV CTR,VIRAL CARCINOGENESIS LAB,FREDERICK,MD 21701.
C3 National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Science Applications International Corporation (SAIC); SAIC-Frederick
RP PACKER, C (corresponding author), UNIV MINNESOTA,DEPT ECOL EVOLUT & BEHAV,MINNEAPOLIS,MN 55455, USA.
NR 27
TC 384
Z9 417
U1 1
U2 116
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 562
EP 565
DI 10.1038/351562a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400057
DA 2026-03-10
ER

PT J
AU CEBRATHOMAS, JA
   DECKER, CL
   SNYDER, LC
   PILDER, SH
   SILVER, LM
AF CEBRATHOMAS, JA
   DECKER, CL
   SNYDER, LC
   PILDER, SH
   SILVER, LM
TI ALLELE-SPECIFIC AND HAPLOID-SPECIFIC PRODUCT GENERATED BY ALTERNATIVE SPLICING FROM A MOUSE T-COMPLEX-RESPONDER LOCUS CANDIDATE
SO NATURE
LA English
DT Article
ID distorter genes; haplotypes; family; dna
AB MOUSE t haplotypes represent a variant form of chromosome 17 that has evolved the ability to propagate through natural populations by the phenomenon of 'transmission ratio distortion' (TRD), in which heterozygous +/t males transmit their t-carrying chromosome to 95% or more of their offspring 1,2.  Although multiple t-associated loci have a role in expression of this phenotype, only one-the t complex responder (Tcr) locus-is responsible for determining which of the two homologues of chromosome 17 will be transmitted at a high ratio 3.  A candiate gene (Tcp-10b) for Tcr that is expressed in both meiotic and post-meiotic male germ cells has been cloned 4.  But for this candiate gene to function as the haploid effector of TRD, the t-allele of this gene (Tcp-10b(t)) must express a unique product in a haploid-specific manner.  Here we show that a change in the splicing pattern of Tcp-10b(t) transcripts occurs during sperm differentiation.  This change results in a unique allele-specific and haploid-specific transcript which could encode a variant polypeptide that would fulfil the conditions required of the Tcr effector of TRD.
C1 PRINCETON UNIV,DEPT MOLEC BIOL,PRINCETON,NJ 08544.
C3 Princeton University
NR 10
TC 45
Z9 52
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 239
EP 241
DI 10.1038/349239a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900055
PM 1987476
DA 2026-03-10
ER

PT J
AU ITO, E
   SATO, H
AF ITO, E
   SATO, H
TI ASEISMICITY IN THE LOWER MANTLE BY SUPERPLASTICITY OF THE DESCENDING SLAB
SO NATURE
LA English
DT Article
ID phase-transformations; lithosphere; deep; earthquakes; deformation; transition; flow
AB IT has been suggested 1-7 that deep earthquakes in subduction zones may be caused by mineralogical transformations in the subducting slab. These transformations, from olivine to modified spinel to spinel, are also thought to affect the rheology of the descending slab 2-4. Experiments in the system Mg2SiO4-Fe2SiO4 (ref. 8) have shown that at still higher pressure, coinciding with the 670-km seismic discontinuity between the upper and lower mantle, spinel dissociates to a fine-grained mixture of perovskite plus magnesiowustite.  Here we argue that the dissociation product in the mantle will also be very fine-grained, and that its eutectoid texture, combined with the low temperature in the slab, will prevent grain growth.  We note (as have others 9,3) that fine-grained materials at moderately high temperatures and low strain rates exhibit super-plastic behaviour; the resulting viscous behaviour of the slab below the spinel dissociation boundary may therefore account for the observed absence of seismicity below approximately 700 km depth, even if slabs do penetrate into the lower mantle.
RP ITO, E (corresponding author), OKAYAMA UNIV,INST STUDY EARTHS INTERIOR,TOTTORI 68201,JAPAN.
NR 28
TC 66
Z9 70
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 140
EP 141
DI 10.1038/351140a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500047
DA 2026-03-10
ER

PT J
AU WHITE, RE
   SCHONBRUNN, A
   ARMSTRONG, DL
AF WHITE, RE
   SCHONBRUNN, A
   ARMSTRONG, DL
TI SOMATOSTATIN STIMULATES CA2+-ACTIVATED K+ CHANNELS THROUGH PROTEIN DEPHOSPHORYLATION
SO NATURE
LA English
DT Article
ID pituitary cell-line; vasoactive intestinal peptide; amp-independent actions; intracellular free calcium; pertussis toxin blocks; cyclic-amp; tumor-cells; gh3 cells; potassium conductance; prolactin secretion
AB THE neuropeptide somatostatin inhibits secretion from electrically excitable cells in the pituitary, pancreas, gut and brain 1.  In mammalian pituitary tumour cells somatostatin inhibits secretion through two distinct pertussis toxin-sensitive mechanisms 2-5.  One involves inhibition of adenylyl cyclase 6, the other an unidentified cyclic AMP-independent mechanism that reduces Ca2+ influx 7,8 by increasing membrane conductance to potassium 9,10.  Here we demonstrate that the predominant electrophysiological effect of somatostatin on metabolically intact pituitary tumour cells is a large, sustained increase in the activity of the large-conductance Ca2+- and voltage-activated K+ channels (BK).  This action of somatostatin does not involve direct effects of Ca2+, cAMP or G proteins on the channels.  Our results indicate instead that somatostatin stimulates BK channel activity through protein dephosphorylation.
C1 NIEHS,CELLULAR & MOLEC PHARMACOL LAB,RES TRIANGLE PK,NC 27709.
   UNIV TEXAS,SCH MED,DEPT PHARMACOL,HOUSTON,TX 77225.
C3 National Institutes of Health (NIH) - USA; NIH National Institute of Environmental Health Sciences (NIEHS); University of Texas System
NR 39
TC 258
Z9 265
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 570
EP 573
DI 10.1038/351570a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400060
PM 1710783
DA 2026-03-10
ER

PT J
AU ORTIZNAVARRETE, V
   SEELIG, A
   GERNOLD, M
   FRENTZEL, S
   KLOETZEL, PM
   HAMMERLING, GJ
AF ORTIZNAVARRETE, V
   SEELIG, A
   GERNOLD, M
   FRENTZEL, S
   KLOETZEL, PM
   HAMMERLING, GJ
TI SUBUNIT OF THE 20S PROTEASOME (MULTICATALYTIC PROTEINASE) ENCODED BY THE MAJOR HISTOCOMPATIBILITY COMPLEX
SO NATURE
LA English
DT Article
ID class-ii region; antigen presentation; cells; identification; transporters; interferon; gene; expression; particles; pathway
AB CYTOTOXiC T lymphocytes recognize fragments (peptides) of protein antigens presented by major histocompatibility complex (MHC) class I molecules. In general, the peptides are derived from cytosolic proteins and are then transported to the endoplasmic reticulum where they assemble with the MHC class I heavy chains and beta-2-microglobulin to form stable and functional class I molecules 1-4. The proteases involved in the generation of these peptides are unknown. One candidate is the proteasome, a nonlysosomal proteinase complex abundantly present in the cytosol. Proteasomes have several proteolytically active sites and are complexes of high relative molecular mass (M(r) about 600K), consisting of about 20-30 subunits with M(r)s between 15 and 30K (refs 5-10). Here we show that at least one of these subunits is encoded by the mouse MHC in the region between the K locus and the MHC class II region, and inducible by interferon-gamma. This raises the intriguing possibility that the MHC encodes not only the MHC class I molecules themselves but also proteases involved in the formation of MHC-binding peptides.
C1 GERMAN CANC RES CTR,INST IMMUNOL & GENET,NEUENHEIMER FELD 280,W-6900 HEIDELBERG,GERMANY.
   UNIV HEIDELBERG,ZMBH,W-6900 HEIDELBERG,GERMANY.
C3 Helmholtz Association; German Cancer Research Center (DKFZ); Ruprecht Karls University Heidelberg
NR 33
TC 247
Z9 262
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 662
EP 664
DI 10.1038/353662a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200071
PM 1922384
DA 2026-03-10
ER

PT J
AU DAVIS, RJ
   UNWIN, SC
   MUXLOW, TWB
AF DAVIS, RJ
   UNWIN, SC
   MUXLOW, TWB
TI LARGE-SCALE SUPERLUMINAL MOTION IN THE QUASAR-3C273
SO NATURE
LA English
DT Article
ID extragalactic radio-sources; 3c273; jets
AB THE quasar 3C273, one of the first discovered 1, is optically the brightest example of a source with a one-sided jet. It was also the first object to display apparent superluminal motion on parsec scales 2, a  phenomenon attributed to relativistic effects on the appearance of a jet moving close to the line of sight 3,4. The same explanation allows an intrinsically similar 'counter-jet', moving at high speed in the opposite direction, to be dimmed to invisibility. We have made observations at 1.7 GHz, using very-long-baseline interferometry with a global network of 16 radiotelescopes, resulting in a high-dynamic-range map of the jet with a ratio of peak brightness to r.m.s. noise level of 16,000:1. We fail to see a counter-jet, a result which is just barely consistent with the standard model of a superluminal jet. The jet extends out to 220 pc, and some models 5,6 require that the relativistic bulk flow should continue along its  entire length. Comparison with an earlier image shows that superluminal motion extends out to at least 120 pc, three times farther than previously noted 7. Because different components emerge with different velocities 7,8, a third epoch of observations is needed to determine if and deceleration has occurred.
C1 CALTECH,PASADENA,CA 91125.
C3 California Institute of Technology
RP DAVIS, RJ (corresponding author), UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,JODRELL BANK,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND.
NR 18
TC 45
Z9 47
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 374
EP 376
DI 10.1038/354374a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100043
DA 2026-03-10
ER

PT J
AU KELLY, A
   POWIS, SH
   GLYNNE, R
   RADLEY, E
   BECK, S
   TROWSDALE, J
AF KELLY, A
   POWIS, SH
   GLYNNE, R
   RADLEY, E
   BECK, S
   TROWSDALE, J
TI 2ND PROTEASOME-RELATED GENE IN THE HUMAN MHC CLASS-II REGION
SO NATURE
LA English
DT Article
ID major histocompatibility complex; multicatalytic proteinase; antigen presentation; lymphocyte-t; transporters; cells; sequences; pathway; cloning; cdna
AB ANTIGEN processing involves the generation of peptides from cytosolic proteins and their transport into the endoplasmic reticulum where they associate with major histocompatibility complex (MHC) class I molecules 1-6. Two genes have been identified in the MHC class II region, RING4 and RING11 in humans, which are believed to encode the peptide transport proteins 7-12. Attention is now focused on how the transporters are provided with peptides. The proteasome, a large complex of subunits with multiple proteolytic activities, is a candidate for this function 13-16. Recently we reported a proteasome-related sequence, RING1O, mapping between the transporter genes 17. Here we describe a second human proteasome-like gene, RING12, immediately centromeric of the RING4 locus. Therefore RING12, 4, 10 and 11 form a tightly linked cluster of interferon-inducible genes within the MHC with an essential role in antigen processing.
RP KELLY, A (corresponding author), IMPERIAL CANC RES FUND,LINCOLNS INN FIELDS,LONDON WC2A 3PX,ENGLAND.
NR 33
TC 349
Z9 369
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 667
EP 668
DI 10.1038/353667a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200073
PM 1922385
DA 2026-03-10
ER

PT J
AU KAGAN, ML
   KEPLER, TB
   EPSTEIN, IR
AF KAGAN, ML
   KEPLER, TB
   EPSTEIN, IR
TI GEOMETRIC PHASE-SHIFTS IN CHEMICAL OSCILLATORS
SO NATURE
LA English
DT Article
ID quantum phase; systems
AB ONE of the most remarkable developments in quantum mechanics in recent years has been the discovery that when a system is moved adiabatically around a closed loop in parameter space there occurs, besides the familiar dynamical phase shift, an additional phase shift (sometimes referred to as 'Berry's phase') that is purely geometric in nature 1-3. The dynamical phase shift, which results from the variation of the period of the oscillatory system with the change in parameters, is relatively easily understood and is proportional to the time over which the parameter change occurs.  The geometric phase shift, on the other hand, is less intuitive and depends on the curvature of the surface in parameters space bounded by the closed path, but is independent of the time taken to traverse the circuit.  Here we present evidence for time-independent geometric phase shifts in numerical solutions for a model of an oscillating chemical reaction.  The conditions for the occurrence of such shifts seem to be sufficiently general that geometric phase effects should be experimentally observable in essentially all chemical oscillators as well as in biological networks such as the brain and the central nervous system, where phase control is of vital importance4.
C1 BRANDEIS UNIV,DEPT BIOL,WALTHAM,MA 02254.
   BRANDEIS UNIV,CTR COMPLEX SYST,WALTHAM,MA 02254.
C3 Brandeis University; Brandeis University
RP KAGAN, ML (corresponding author), BRANDEIS UNIV,DEPT CHEM,WALTHAM,MA 02254, USA.
NR 18
TC 20
Z9 21
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 506
EP 508
DI 10.1038/349506a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100059
PM 1992353
DA 2026-03-10
ER

PT J
AU WELLS, ML
   GOLDBERG, ED
AF WELLS, ML
   GOLDBERG, ED
TI OCCURRENCE OF SMALL COLLOIDS IN SEA-WATER
SO NATURE
LA English
DT Article
ID aggregation; particles
AB COLLOIDAL particles in sea water may be important in the marine chemistry of elements such as carbon and iron 1,2.  Non-living, submicrometre particles (0.4-1.0-mu-m) have recently been found to be abundant (10(6)-10(7) particles ml-1) in the north Pacific 3 and off Nova Scotia 4, but smaller colloidal particles in sea water remain largely uncharacterized.  Here we report that marine colloids < 120 nm in size are at least three orders of magnitude more abundant than larger submicrometre particles.  Moreover, the distribution with depth of these small colloids differs markedly from that reported for their larger counterparts 3.  This vertical stratification suggests that small colloidal particles in sea water are reactive.  Examination by transmission electron microscopy and energy-dispersive X-ray spectroscopy indicates that the colloids are largely organic, although trace metals (Fe, Al, Co) may also be present.  The existence of such colloids may contribute to the discrepancy between standard and new high-temperature methods for measuring dissolved organic carbon 1.
RP WELLS, ML (corresponding author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093, USA.
NR 13
TC 236
Z9 271
U1 1
U2 53
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 342
EP 344
DI 10.1038/353342a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400056
DA 2026-03-10
ER

PT J
AU MORTLOCK, RA
   CHARLES, CD
   FROELICH, PN
   ZIBELLO, MA
   SALTZMAN, J
   HAYS, JD
   BURCKLE, LH
AF MORTLOCK, RA
   CHARLES, CD
   FROELICH, PN
   ZIBELLO, MA
   SALTZMAN, J
   HAYS, JD
   BURCKLE, LH
TI EVIDENCE FOR LOWER PRODUCTIVITY IN THE ANTARCTIC OCEAN DURING THE LAST GLACIATION
SO NATURE
LA English
DT Article
ID atmospheric co2; high-latitude; ice ages; waters; dissolution; diatoms
AB BOTH increased biological productivity and more efficient uptake of upwelled nutrients in high-latitude oceans have been proposed 1-5 as mechanisms responsible for the glacial reduction in atmospheric concentrations of carbon dioxide deduced from ice-core measurements 6-8. These glacial models invoke more efficient 'biological pumping' of carbon into the deep sea by increasing the uptake of 'excess' biolimiting nutrients in the Antarctic surface ocean 9 or by reorganizing chemical circulation patterns within the ocean 10,11. Here we challenge this conventional view with new evidence from tracers of palaeoproductivity preserved in Antarctic sediments. Records of the accumulation rates of diatom shells, the ratio of germanium to silicon in diatomaceous opal and the carbon isotope ratio in foraminiferal carbonate all suggest lower glacial productivity and less efficient uptake of nutrients. Although alternative interpretations are possible, our results support previous studies that indicate lower glacial productivity in the Southern Ocean 12,13 and raise new questions about the role of ocean productivity in models of the causes (or remedies) for changes in atmospheric concentrations of carbon dioxide.
C1 COLUMBIA UNIV, DEPT GEOL SCI, PALISADES, NY 10964 USA.
C3 Columbia University
RP MORTLOCK, RA (corresponding author), COLUMBIA UNIV, LAMONT DOHERTY GEOL OBSERV, PALISADES, NY 10964 USA.
NR 39
TC 254
Z9 285
U1 1
U2 39
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 220
EP 223
DI 10.1038/351220a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000052
DA 2026-03-10
ER

PT J
AU RUDEN, DM
   MA, J
   LI, Y
   WOOD, K
   PTASHNE, M
AF RUDEN, DM
   MA, J
   LI, Y
   WOOD, K
   PTASHNE, M
TI GENERATING YEAST TRANSCRIPTIONAL ACTIVATORS CONTAINING NO YEAST PROTEIN SEQUENCES
SO NATURE
LA English
DT Article
AB WE previously reported that roughly 1% of the short peptides encoded by Escherichia coli genomic DNA fragments act as transcriptional activating regions in yeast when fused to GAL4(1-147), a DNA-binding portion of the yeast transcriptional activator GAL4 (ref. 1).  Struhl questioned the conclusion that we had identified new transcriptional activating sequences that function in the absence of yeast transcriptional activating sequences 2.  His criticism was based on two considerations:  first, GAL4(1-147) contains an acidic segment (and subsequent experiments have shown that this region contains a weak activating region in vitro 3); second, attempts to isolate new activating regions failed when the DNA-binding domain of a bacterial repressor, LexA(1-87), was used as the DNA-binding unit 2.  We report here a repeat of our original experiment using the complete LexA molecule LexA(1-202) as the DNA-binding region, instead of GAL4(1-147) or LexA(1-87).  We find that, as in the original experiment, about 1% of the short peptides encoded by E. coli genomic fragments act as transcriptional activating regions when fused to intact LexA.  All of the new activating regions whose sequences we determined bore an excess of acidic amino acids (see Table 1).
C1 HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,7 DIVIN AVE,CAMBRIDGE,MA 02138.
C3 Harvard University
NR 8
TC 141
Z9 161
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 250
EP 252
DI 10.1038/350250a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900064
PM 2005981
DA 2026-03-10
ER

PT J
AU SLOANE, DL
   LEUNG, R
   CRAIK, CS
   SIGAL, E
AF SLOANE, DL
   LEUNG, R
   CRAIK, CS
   SIGAL, E
TI A PRIMARY DETERMINANT FOR LIPOXYGENASE POSITIONAL SPECIFICITY
SO NATURE
LA English
DT Article
ID low-density-lipoprotein; human reticulocyte 15-lipoxygenase; molecular-cloning; substrate-specificity; human 5-lipoxygenase; iron environment; expression; protein; cdna; 12-lipoxygenase
AB THE three mammalian lipoxygenases are named according to the carbon position (5, 12 or 15) at which they catalyse the oxygenation of arachidonic acid 1; they are implicated in inflammatory disorders, for example 15-lipoxygenase is induced in atherosclerosis 2 and can oxidize low-density lipoprotein to its atherogenic form 3,4. To identify what determines this positional specificity, we have exchanged conserved differences in the isoforms of 12- and 15-lipoxygenases. Substitution of methionine with valine at position 418 of human 15-lipoxygenase results in an enzyme that performs 12- and 15-lipoxygenation equally. This effect can be mimicked by incubating wild-type 15-lipoxygenase with a synthetically altered substrate which has its doubly allylic methylene carbons shifted by one carbon relative to arachidonic acid. Other mutations at the neighbouring amino acids 416 and 417 give an enzyme which performs 12- and 15-lipoxygenation in a ratio of 15:1. These results indicate that this region might position the substrate in the active site.
C1 UNIV CALIF SAN FRANCISCO,CARDIOVASC RES INST,SAN FRANCISCO,CA 94143.
   UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143.
   UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94143.
C3 University of California System; University of California San Francisco; University of California System; University of California San Francisco; University of California System; University of California San Francisco
NR 28
TC 205
Z9 220
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 149
EP 152
DI 10.1038/354149a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000060
PM 1944593
DA 2026-03-10
ER

PT J
AU MOLNAR, Z
   BLAKEMORE, C
AF MOLNAR, Z
   BLAKEMORE, C
TI LACK OF REGIONAL SPECIFICITY FOR CONNECTIONS FORMED BETWEEN THALAMUS AND CORTEX IN COCULTURE
SO NATURE
LA English
DT Article
ID cerebral-cortex; cortical areas; visual-cortex; rat; cultures; projections; pathway; neurons
AB THE mammalian cerebral cortex consists of many structurally 1 and functionally 2 specialized areas, with characteristic input from particular nuclei of the thalamus. Some localized external influence, such as the arrival of fibres from the appropriate thalamic nucleus before or around the time of birth 3-6, could trigger the emergence of committed cortical fields from an undifferentiated 'protocortex' 7,8. The guidance of axons from each thalamic nucleus to its appropriate target area in the cortex could, then, be crucial in the regulation of cortical differentiation. Recently, Yamamoto et al. 9 and Bolz et al. 10 have demonstrated that cocultured explants of rat lateral geniculate nucleus and visual cortex can form layer-specific interconnections. We have now tested the possibility that each cortical area exerts a selective trophic influence on axons from its appropriate thalamic nucleus, and vice versa, by coculturing explants of different regions of the thalamus and cortex taken at various stages of development.
RP MOLNAR, Z (corresponding author), UNIV OXFORD, PHYSIOL LAB, PARKS RD, OXFORD OX1 3PT, ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 20
TC 197
Z9 204
U1 0
U2 3
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 475
EP 477
DI 10.1038/351475a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800053
PM 2046749
DA 2026-03-10
ER

PT J
AU PROSPERO, JM
   SAVOIE, DL
   SALTZMAN, ES
   LARSEN, R
AF PROSPERO, JM
   SAVOIE, DL
   SALTZMAN, ES
   LARSEN, R
TI IMPACT OF OCEANIC SOURCES OF BIOGENIC SULFUR ON SULFATE AEROSOL CONCENTRATIONS AT MAWSON, ANTARCTICA
SO NATURE
LA English
DT Article
ID sea-salt sulfate; methanesulfonic-acid; seasonal-variations; dimethylsulfide; atmosphere; continent; winds
AB Sulphate is the dominant aerosol species in the Antarctic atmosphere 1,2 and an important constituent in Antarctic snow and ice 3.  Various sources have been suggested for Antarctic non-sea-salt sulphate (n.s.s. SO4(2-)):  volcanic emissions, stratospheric injection, pollutants transported from the low latitudes and biogenic dimethylsulphide (DMS) from the ocean 1,2.  Although the oceanic source is now believed to be especially important, there has been no strong chemical evidence directly linking oceanic DMS with the Antarctic n.s.s. SO4(2-) concentrations.  Here we present extended measurements from the Antarctic for both n.s.s.  SO4(2-) and methanesulphonate (MSA), an oxidation product of DMS.  Both species have a very strong seasonal cycle with a maximum in the austral summer; this cycle parallels that of the oceanic biogenic sulphur producers, thereby suggesting a strong link between the Antarctic atmospheric sulphur cycle and biological processes in the Southern Ocean.
C1 US DOE,ENVIRONM MEASUREMENTS LAB,NEW YORK,NY 10014.
C3 United States Department of Energy (DOE)
RP PROSPERO, JM (corresponding author), UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MAC,4600 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA.
NR 28
TC 112
Z9 118
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 221
EP 223
DI 10.1038/350221a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900053
DA 2026-03-10
ER

PT J
AU KRAUSS, S
   JOHANSEN, T
   KORZH, V
   FJOSE, A
AF KRAUSS, S
   JOHANSEN, T
   KORZH, V
   FJOSE, A
TI EXPRESSION PATTERN OF ZEBRAFISH PAX GENES SUGGESTS A ROLE IN EARLY BRAIN REGIONALIZATION
SO NATURE
LA English
DT Article
ID developing excretory system; proto-oncogene int-1; drosophila; conservation; hindbrain; embryos
AB IN vertebrates the developing hindbrain is organized in segmental units 1.  These units provide the primary grid for differentiation and axonal outgrowth 1,2.  In the more anterior regions of the brain, however, the subdivisions remain more controversial. Cellular and molecular studies of the embryonic brain in lower vertebrates such as the zebrafish, Brachydanio rerio, may reveal remnants of such subdivisions. We have isolated complementary DNA clones for two zebrafish pax genes related to Drosophila and mouse paired-box-containing segmentation genes 3-10.  The expression of these two genes is confined to specific regions in the embryonic forebrain and midbrain. Strikingly, the borders of expression of the two pax genes coincide with morphological landmarks corresponding to the primary axon tracts that are generated in the embryonic brain a few hours after the initiation of expression of these genes 11,12.
C1 UNIV TROMSO,INST MED BIOL,DEPT MICROBIOL,BIOTECHNOL GRP,N-9000 TROMSO,NORWAY.
C3 UiT The Arctic University of Tromso
RP KRAUSS, S (corresponding author), UNIV TROMSO,INST MED BIOL,DEPT MICROBIOL,MOLEC GENET GRP,N-9000 TROMSO,NORWAY.
NR 23
TC 239
Z9 260
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 267
EP 270
DI 10.1038/353267a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400063
PM 1680220
DA 2026-03-10
ER

PT J
AU REMILLARD, RA
   GROSSAN, B
   BRADT, HV
   OHASHI, T
   HAYASHIDA, K
   MAKINO, F
   TANAKA, Y
AF REMILLARD, RA
   GROSSAN, B
   BRADT, HV
   OHASHI, T
   HAYASHIDA, K
   MAKINO, F
   TANAKA, Y
TI A RAPID ENERGETIC X-RAY FLARE IN THE QUASAR PKS0558-504
SO NATURE
LA English
DT Article
ID active galactic nuclei; bl-lacertae object; superluminal motion; variability; emission; ginga
AB QUASARS normally exhibit only small fluctuations in brightness, but occasional instances of substantial variability have been used to constrain the size and geometry of the emitting region.  Here we report a recent observation from the Ginga satellite 1 of the quasar PKS0558-504, during which the X-ray flux increased by 67% in the space of only 3 minutes.  There was no significant change in the spectrum.  Comprehensive analysis of the data strongly indicates that this was a genuine X-ray flare originating in the quasar.  The implied rate of change in luminosity in the 2-10 keV range, assuming a Hubble constant of 70 km s-1 Mpc-1 and a cosmological deceleration parameter q0 = 0.5, is 3.2 x 10(42) erg s-2, the highest value measured for a quasar.  When photon scattering is considered, this is approximately 16 times greater than could be produced, with a 3-minute rise time, in an isotropically emitting plasma.  We argue that the apparent luminosity must be enhanced by relativistic beaming.  This is the first indication of beaming in an 'ordinary' unpolarized quasar.
C1 UNIV TOKYO,DEPT PHYS,BUNKYO KU,TOKYO 113,JAPAN.
   INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN.
C3 University of Tokyo; Japan Aerospace Exploration Agency (JAXA); Institute of Space & Astronautical Science (ISAS)
RP REMILLARD, RA (corresponding author), MIT,CTR SPACE RES,CAMBRIDGE,MA 02139, USA.
NR 27
TC 49
Z9 52
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 589
EP 592
DI 10.1038/350589a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200051
DA 2026-03-10
ER

PT J
AU WOJCIECHOWSKI, AP
   FARRALL, M
   CULLEN, P
   WILSON, TME
   BAYLISS, JD
   FARREN, B
   GRIFFIN, BA
   CASLAKE, MJ
   PACKARD, CJ
   SHEPHERD, J
   THAKKER, R
   SCOTT, J
AF WOJCIECHOWSKI, AP
   FARRALL, M
   CULLEN, P
   WILSON, TME
   BAYLISS, JD
   FARREN, B
   GRIFFIN, BA
   CASLAKE, MJ
   PACKARD, CJ
   SHEPHERD, J
   THAKKER, R
   SCOTT, J
TI FAMILIAL COMBINED HYPERLIPEMIA LINKED TO THE APOLIPOPROTEIN AI-CIII-AIV GENE-CLUSTER ON CHROMOSOME-11Q23-Q24
SO NATURE
LA English
DT Article
ID triglyceride-rich lipoproteins; coronary heart-disease; dna polymorphisms; linkage analysis; lipid-levels; deficiency; humans
AB Familial combined hyperlipidaemia (FCHL) is a common inherited disorder of lipid metabolism with a prevalence of 0.5-2.0% (refs 1,2).  It is estimated to cause 10% of premature coronary heart disease 1,3.  The underlying metabolic and genetic defects in FCHL have not been identified, but a population study has suggested an association between FCHL and an XmnI restriction fragment length polymorphism (RFLP) within the apolipoprotein AI-CIII-AIV gene cluster 4.  Here we confirm this association and show that it results from linkage disequilibrium between FChl and the 6.6-kilobase (kb) allele of the XmnI RFLP.  Subsequent analysis in seven FChl families, ascertained through a proband carrying the 6.6 kb XmnI allele, demonstrated linkage to the AI-CIII-AIV cluster on 11q23-q24, z = 6.86 with no recombinants.  This assignment will facilitate the identification of the mutation that causes hyperlipidaemia in these families.
C1 NORTHWICK PK HOSP & CLIN RES CTR,MRC,CLIN RES CTR,DIV MOLEC MED,WATFORD RD,HARROW HA1 3UJ,MIDDX,ENGLAND.
   GLASGOW ROYAL INFIRM,INST PATHOL BIOCHEM,GLASGOW G4 0SF,SCOTLAND.
C3 Imperial College London; Medical Research Council Clinical Trials Unit; University of Glasgow
NR 24
TC 176
Z9 185
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 161
EP 164
DI 10.1038/349161a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800060
PM 1670899
DA 2026-03-10
ER

PT J
AU KARLSSON, L
   SURH, CD
   SPRENT, J
   PETERSON, PA
AF KARLSSON, L
   SURH, CD
   SPRENT, J
   PETERSON, PA
TI A NOVEL CLASS-II MHC MOLECULE WITH UNUSUAL TISSUE DISTRIBUTION
SO NATURE
LA English
DT Article
ID major histocompatibility complex; t-cells; e-alpha; antigen; expression; mouse; genes; selection; invivo
AB THE repertoire of mature class II-restricted T cells is generated through a complex process of selection whereby early T cells confront class II molecules in the thymus, especially on epithelial cells 1-3. Expression of class II molecules on such cells is prominent both in the cortex and in the medulla 4,5. We have identified a novel class II molecule, H-2O, which is expressed only in epithelial cells of the thymic medulla and in B cells. The unusual tissue distribution and the nonpolymorphic nature of H-2O suggest that its function is different from that of classical class II molecules.
RP KARLSSON, L (corresponding author), SCRIPPS CLIN & RES FDN, DEPT IMMUNOL, 10666 N TORREY PINES RD, LA JOLLA, CA 92037 USA.
NR 23
TC 123
Z9 138
U1 0
U2 0
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 485
EP 488
DI 10.1038/351485a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800057
PM 1675431
DA 2026-03-10
ER

PT J
AU ROCHE, PA
   MARKS, MS
   CRESSWELL, P
AF ROCHE, PA
   MARKS, MS
   CRESSWELL, P
TI FORMATION OF A NINE-SUBUNIT COMPLEX BY HLA CLASS-II GLYCOPROTEINS AND THE INVARIANT CHAIN
SO NATURE
LA English
DT Article
ID lymphoblastoid cell; beta-chain; antigens; proteins; binding; glycosylation; association; peptide
AB HLA CLASS II molecules are heterodimeric transmembrane glycoproteins that bind and present processed antigenic peptides to CD4-positive T lymphocytes. Intracellularly, class II molecules associate with a third subunit termed the invariant (1) chain. Here we describe the physical characteristics of the intracellular class II alpha-beta-I complex. Chemical crosslinking, size exclusion chromatography and sedimentation velocity studies demonstrate that the alpha-beta-I complex is a nine-subunit transmembrane protein that contains three alpha-beta-dimers associated with an I chain trimer. The organization of class II alpha- and beta-subunits in such a multimer may have a role in the documented ability of the I chain to inhibit peptide binding to class II molecules 1-3. In addition, the formation of the nine-chain complex may induce the structural changes necessary to overcome the cytoplasmic retention signal responsible for the localization of free I chain in the endoplasmic reticulum, releasing class II-I chain complexes for transport to endosomes 4-6.
C1 DUKE UNIV,MED CTR,DEPT MICROBIOL & IMMUNOL,DURHAM,NC 27710.
C3 Duke University
NR 22
TC 320
Z9 360
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 392
EP 394
DI 10.1038/354392a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100051
PM 1956401
DA 2026-03-10
ER

PT J
AU TOMALSKI, MD
   MILLER, LK
AF TOMALSKI, MD
   MILLER, LK
TI INSECT PARALYSIS BY BACULOVIRUS-MEDIATED EXPRESSION OF A MITE NEUROTOXIN GENE
SO NATURE
LA English
DT Article
ID pyemotes-tritici; transcription; vectors; toxins
AB FEMALE mites of the species Pyemotes tritici inject an extremely potent venom into their insect prey that causes muscle-contraction and paralysis 1-4. These mites are able to paralyse insects 150,000 times their size 5 and their venom is effective in a broad range of insect species 4. A toxin (TxP-I) associated with the mite venom apparatus causes immediate muscle-contractive paralysis when injected into insects but not mice 6. In this report, we describe the cloning, sequencing and expression of a complementary DNA (Tox-34) encoding TxP-I. Insect cells infected with a recombinant baculovirus (vEV-Tox34) expressing Tox-34 secrete three polypeptides related to TxP-I which cause paralysis on injection. Larvae infected with vEV-Tox34 become paralysed during infection, thus reflecting the potential application of this toxin gene in insect biocontrol methods. The toxin gene expression system will also allow further exploration of the neurophysiological basis of its insect-specific effects.
C1 UNIV GEORGIA,DEPT GENET,ATHENS,GA 30602.
C3 University System of Georgia; University of Georgia
RP TOMALSKI, MD (corresponding author), UNIV GEORGIA,DEPT ENTOMOL,ATHENS,GA 30602, USA.
NR 19
TC 230
Z9 277
U1 0
U2 19
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 82
EP 85
DI 10.1038/352082a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800077
PM 1840646
DA 2026-03-10
ER

PT J
AU MARRACK, P
   KUSHNIR, E
   KAPPLER, J
AF MARRACK, P
   KUSHNIR, E
   KAPPLER, J
TI A MATERNALLY INHERITED SUPERANTIGEN ENCODED BY A MAMMARY-TUMOR VIRUS
SO NATURE
LA English
DT Article
ID major histocompatibility complex; nucleotide-sequence; expression; gene; reactivity; tolerance; products; region; mls
AB A COLLECTION of superantigens, molecules which in combination with class II major histocompatibility complex (MHC) engage T cells bearing particular V-beta chains as part of their alpha-beta receptors, have recently been described 1,2.  The mouse self superantigen, Mls-1a, for example, in conjunction with many MHC class II proteins, engages mouse T cells bearing V-beta-6, 7, 8.1 and 9, almost regardless of the sequences of the other variable components of the receptors on the T cells 3-5. Two types of superantigen have been identified so far:  first, superantigens encoded in the mouse genome, such as mls-1a; second, superantigens produced by bacteria, such as the staphylococcal enterotoxins 1,2. Although the latter type of super-antigens are in many cases known to be proteins of about 220 amino acids 6,7, nothing is known about the structures of any of the superantigens encoded in mouse. Here we describe the properties of a new mouse superantigen.  The antigen is maternally transmitted in milk and is probably encoded by a mammary tumour virus (MTV).  Given the known genetic linkage between at least one of the mouse genomic superantigens and endogenous MTV integration sites 8, it is tempting to speculate that the superantigen described here and some of the endogenous mouse superantigens are encoded by MTVs.
RP MARRACK, P (corresponding author), NATL JEWISH CTR IMMUNOL & RESP MED,DEPT MED,HOWARD HUGHES MED INST,DENVER,CO 80206, USA.
NR 20
TC 347
Z9 364
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 524
EP 526
DI 10.1038/349524a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100066
PM 1846947
DA 2026-03-10
ER

PT J
AU CHO, SG
   ATTAYA, M
   MONACO, JJ
AF CHO, SG
   ATTAYA, M
   MONACO, JJ
TI NEW CLASS-II-LIKE GENES IN THE MURINE MHC
SO NATURE
LA English
DT Article
ID major histocompatibility complex; chain gene; nucleotide-sequence; beta-chain; mouse; alpha; cdna; haplotype; subregion; distinct
AB MAJOR histocompatibility complex (MHC) class I molecules present endogenous antigens to CD8+ (cytotoxic) T cells.  MHC class II molecules present primarily exogenously derived antigens to CD4+ T cells.  Three new genes (Ma, Mb1 and Mb2) located between the Pb and Ob genes of the murine MHC have properties indicating that they are members of the MHC class II gene family, but they are the most divergent class II members so far identified and are almost as closely related in sequence to class I genes as they are to the known class II genes.
RP CHO, SG (corresponding author), VIRGINIA COMMONWEALTH UNIV,MED COLL VIRGINIA,DEPT MICROBIOL & IMMUNOL,RICHMOND,VA 23298, USA.
NR 23
TC 122
Z9 134
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 573
EP 576
DI 10.1038/353573a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300073
PM 1922366
DA 2026-03-10
ER

PT J
AU HYMAN, AA
   MITCHISON, TJ
AF HYMAN, AA
   MITCHISON, TJ
TI 2 DIFFERENT MICROTUBULE-BASED MOTOR ACTIVITIES WITH OPPOSITE POLARITIES IN KINETOCHORES
SO NATURE
LA English
DT Article
ID cytoplasmic dynein; protein; spindle; kinesin; drosophila; poleward; mitosis; force; dephosphorylation; micromanipulation
AB The movement of microtubules on the kinetochores of isolated chromosomes has been examined by video microscopy. Two different microtubule-based motors on the kinetochore were identified, which have opposite directions of movement. The activities of these two motors can be regulated by factors that can influence phosphorylation.
RP HYMAN, AA (corresponding author), UNIV CALIF SAN FRANCISCO, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA.
NR 43
TC 181
Z9 190
U1 0
U2 3
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 206
EP 211
DI 10.1038/351206a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000047
PM 2041567
DA 2026-03-10
ER

PT J
AU DALY, MC
   LAWRENCE, SR
   KIMUNA, D
   BINGA, M
AF DALY, MC
   LAWRENCE, SR
   KIMUNA, D
   BINGA, M
TI LATE PALEOZOIC DEFORMATION IN CENTRAL AFRICA - A RESULT OF DISTANT COLLISION
SO NATURE
LA English
DT Article
AB SEISMIC reflection profiles from the Cuvette Centrale (Central Basin) of Zaire show that a major contractional deformation affected a part of central Africa during the late Permian and early Triassic periods. At the same time, other regions of central Africa experienced extensional and strike-slip deformation and associated rift formation. The coexistence of such varied styles of tectonic activity over a large continental area resembles the Cenozoic tectonics of central Asia and northwest Europe. The intracontinental deformation seen in these latter areas is attributed to collisional processes at a distant continental margin 1-3. By analogy, we argue here that deformation of central Africa in the late Palaeozoic period was a direct result of collisional processes some distance away at the southern margin of Gondwana.
C1 QUAD CONSULTING, OXFORD, ENGLAND.
   MINIST MINES & ENERGY, CTP PETROZAIRE, KINSHASA, DEM REP CONGO.
RP DALY, MC (corresponding author), BP EXPLORAT CO LTD, GLOBAL BASIN ANAL GRP, BRITANN HOUSE, MOOR LANE, LONDON EC2Y 9BU, ENGLAND.
NR 21
TC 70
Z9 73
U1 0
U2 5
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 605
EP 607
DI 10.1038/350605a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200058
DA 2026-03-10
ER

PT J
AU GREGORY, CD
   DIVE, C
   HENDERSON, S
   SMITH, CA
   WILLIAMS, GT
   GORDON, J
   RICKINSON, AB
AF GREGORY, CD
   DIVE, C
   HENDERSON, S
   SMITH, CA
   WILLIAMS, GT
   GORDON, J
   RICKINSON, AB
TI ACTIVATION OF EPSTEIN-BARR-VIRUS LATENT GENES PROTECTS HUMAN B-CELLS FROM DEATH BY APOPTOSIS
SO NATURE
LA English
DT Article
ID endemic burkitts-lymphoma; dependence; expression; phenotype; lines; ebv
AB EPSTEIN-Barr virus (EBV), a human herpesvirus, establishes a persistent asymptomatic infection of the circulating B-lymphocyte pool 1-3. The mechanism of virus persistence is not understood but, given the limited lifespan of most B cells in vivo, it seems most likely that EBV-infected cells must gain access to the long-lived memory B-cell pool. Here we show in an in vitro system that EBV, through expression of the full set of eight virus-coded 'latent' proteins, can protect human B cells from programmed cell death (apoptosis), the deletion mechanism which normally restricts entry into memory 4. We have found that EBV-positive Burkitt's lymphoma (BL) cell clones 5 retaining the original tumour cell phenotype and expressing only one of the virus latent proteins, the nuclear antigen EBNA 1, are extremely sensitive to apoptosis; in this respect they resemble the tumour's normal cell of origin found in the germinal centres of lymphoid tissue. By contrast, isogenic BL cell clones which have activated expression of all eight EBV latent proteins are resistant to the induction of apoptosis. The EBV latent proteins should therefore be seen not just as activators of B-cell proliferation but, perhaps more importantly, as mediators of enhanced B-cell survival.
C1 UNIV BIRMINGHAM, SCH MED, DEPT CANC STUDIES, BIRMINGHAM B15 2TT, W MIDLANDS, ENGLAND.
   UNIV BIRMINGHAM, DEPT ANAT, BIRMINGHAM B15 2TT, W MIDLANDS, ENGLAND.
   UNIV ASTON, INST PHARMACEUT SCI, BIRMINGHAM B4 7ET, W MIDLANDS, ENGLAND.
C3 University of Birmingham; University of Birmingham; Aston University
RP GREGORY, CD (corresponding author), UNIV BIRMINGHAM, SCH MED, DEPT IMMUNOL, BIRMINGHAM B15 2TT, W MIDLANDS, ENGLAND.
NR 23
TC 514
Z9 541
U1 1
U2 13
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 612
EP 614
DI 10.1038/349612a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000060
PM 1705663
DA 2026-03-10
ER

PT J
AU BACHELERIE, F
   ALCAMI, J
   ARENZANASEISDEDOS, F
   VIRELIZIER, JL
AF BACHELERIE, F
   ALCAMI, J
   ARENZANASEISDEDOS, F
   VIRELIZIER, JL
TI HIV ENHANCER ACTIVITY PERPETUATED BY NF-KAPPA-B INDUCTION ON INFECTION OF MONOCYTES
SO NATURE
LA English
DT Article
ID human immunodeficiency virus; gene-expression; alpha; transcription; interleukin-1; activation; mitogens
AB PERMISSIVENESS to replication of human immunodeficiency virus (HIV) differs in T lymphocytes and macrophages.  In T cells, HIV transcription is poorly detected in vivo 1.  Cloned, normal T lymphocytes show very little, if any, basal activity of the HIV enhancer and low nuclear expression of NF-kappa-B 2, a potent transcriptional activator of the HIV enhancer 3-5.  In contrast, fixed tissue macrophages express detectable HIV proteins, indicating permanent virus transcription 6.  One explanation for the perpetuation of virus infection in macrophages could be sustained nuclear NF-kappa-B expression.  However, the U937 monocytic cell line, which is fully permissive to HIV replication, is known to express only low levels of nuclear  NF-kappa-B 7.  We show here that chronic HIV infection results in both induction of a nuclear factor with antigenic properties indistinguishable from those of NF-kappa-B and permanently increased HIV enhancer activity.  This phenomenon, which is independent of tumour necrosis factor, is associated with HIV replication, and is thus likely to explain at least in part the perpetuation of HIV infection in monocytes.
C1 INST PASTEUR,UNITE IMMUNOL VIRALE,28 RUE DR ROUX,F-75724 PARIS 15,FRANCE.
C3 Pasteur Network; Universite Paris Cite; Institut Pasteur Paris
NR 26
TC 182
Z9 194
U1 0
U2 5
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 709
EP 712
DI 10.1038/350709a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000061
PM 2023633
DA 2026-03-10
ER

PT J
AU KIM, CM
   KOIKE, K
   SAITO, I
   MIYAMURA, T
   JAY, G
AF KIM, CM
   KOIKE, K
   SAITO, I
   MIYAMURA, T
   JAY, G
TI HBX GENE OF HEPATITIS-B VIRUS INDUCES LIVER-CANCER IN TRANSGENIC MICE
SO NATURE
LA English
DT Article
ID hepatocellular-carcinoma; x-protein; mouse model; tat gene; expression; antigen; tumors; activation; integration; secretion
AB THE exact role of hepatitis B virus in the development of liver cancer is not known.  The recent identification of a viral regulatory gene HBx suggests a possible direct involvement of the virus whereby the HBx protein, acting as a transcriptional transactivator of viral genes, may alter host gene expression and lead to the development of hepatocellular carcinoma.  We have tested this possibility by placing the entire HBx gene under its own regulatory elements directly into the germline of mice.  Transgenic animals harbouring this viral gene succumbed to progressive histopathological changes specifically in the liver, beginning with multifocal areas of altered hepatocytes, followed by the appearance of benign adenomas, and proceeding to the development of malignant carcinomas.  Male mice developed disease and died much earlier than females.  This transgenic animal model appears ideal for defining the molecular events that follow the expression of the viral HBx gene and are responsible for the development of liver cancer.
C1 AMER RED CROSS,JEROME H HOLLAND LAB,VIROL LAB,ROCKVILLE,MD 20855.
   NATL INST HLTH,DEPT ENTEROVIRUSES,HEPATITIS VIRUSES LAB,TOKYO 141,JAPAN.
C3 American Red Cross; National Institute of Health Sciences - Japan
NR 39
TC 1039
Z9 1143
U1 2
U2 64
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 317
EP 320
DI 10.1038/351317a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600061
PM 2034275
DA 2026-03-10
ER

PT J
AU COLLERSON, KD
   CAMPBELL, LM
   WEAVER, BL
   PALACZ, ZA
AF COLLERSON, KD
   CAMPBELL, LM
   WEAVER, BL
   PALACZ, ZA
TI EVIDENCE FOR EXTREME MANTLE FRACTIONATION IN EARLY ARCHEAN ULTRAMAFIC ROCKS FROM NORTHERN LABRADOR
SO NATURE
LA English
DT Article
ID terrestrial magma ocean; west greenland; early differentiation; isotope systematics; continental-crust; greenstone belts; trace-elements; sr-isotope; sm-nd; constraints
AB Samarium-neodymium isotope data for tectonically interleaved fragments of lithospeheric mantle and meta-komatiite from the North Atlantic craton provide the first direct record of mantle differentiation before 3,800 Myr ago.  The results confirm the magnitude of light-rare-earth-element depletion the magnitude of light-rare-earth-element depletion in the early mantle, and also its depleted neodymium isotope composition.  The mantle fragments were able to retain these ancient geochemical signatures by virtue of having been tectonically incorporated in buoyant felsic crust, thus escaping recycling and homogenization by mantle convection.
C1 UNIV OKLAHOMA,SCH GEOL & GEOPHYS,NORMAN,OK 73019.
   VG ISOTECH,MIDDLEWICH CW10 0HT,CHESHIRE,ENGLAND.
C3 University of Oklahoma System; University of Oklahoma - Norman
RP COLLERSON, KD (corresponding author), UNIV CALIF SANTA CRUZ,EARTH SCI BOARD,SANTA CRUZ,CA 95064, USA.
NR 53
TC 94
Z9 99
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 209
EP 214
DI 10.1038/349209a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900045
DA 2026-03-10
ER

PT J
AU BALLOU, LM
   LUTHER, H
   THOMAS, G
AF BALLOU, LM
   LUTHER, H
   THOMAS, G
TI MAP2 KINASE AND 70K-S6 KINASE LIE ON DISTINCT SIGNALING PATHWAYS
SO NATURE
LA English
DT Article
ID ribosomal-protein s6; serine-threonine kinase; swiss mouse 3t3-cells; 3t3 cells; insulin; activation; serum; phosphorylation; purification; identification
AB ACTIVATION of protein synthesis is required for quiescent cells to transit the cell cycle1, and seems to be mediated in part by phosphorylation of the 40S ribosomal protein, S6 (ref. 2).  A mitogen-activated S6 kinase of relative molecular mass 70,000 (70K) has been isolated from mouse fibroblasts3,4 as well as from avian, rat and rabbit tissues5-9.  Comparison of complementary DNA sequences shows that this enzyme10 is distinct from S6 kinase II (92K)11 found in Xenopus eggs12 and fibroblasts13,14.  Both kinases are activated by serine/threonine phosphorylation3,15-18, suggesting that at least one serine/threonine kinase links receptor tyrosine kinases with S6 kinases.  A candidate for this link is MAP2 kinase, which is rapidly activated by tyrosine/threonine phosphorylation following mitogenic stimulation19-23.  Incubation of MAP2 kinase from insulin-treated 3T3-L1 adipocytes with phosphatase-inactivated S6 kinase II from Xenopus leads to partial reactivation and phosphorylation of the enzyme17.  These and other findings8 have led to the suggestion that MAP2 kinase also activates the 70K S6 kinase.  Here we refute this idea by showing that the two kinases lie on distinct signalling pathways.
C1 FRIEDRICH MIESCHER INST,POSTFACH 2543,CH-4002 BASEL,SWITZERLAND.
C3 Friedrich Miescher Institute for Biomedical Research
NR 28
TC 205
Z9 213
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 348
EP 350
DI 10.1038/349348a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100059
PM 1702881
DA 2026-03-10
ER

PT J
AU ETTL, R
   CHAO, I
   DIEDERICH, F
   WHETTEN, RL
AF ETTL, R
   CHAO, I
   DIEDERICH, F
   WHETTEN, RL
TI ISOLATION OF C76, A CHIRAL (D2) ALLOTROPE OF CARBON
SO NATURE
LA English
DT Article
ID c-60; clusters; spectra; form; c-70
AB A LONG search for molecular allotropic forms of carbon 1-4 culminated in the discovery 5-7 of a method for preparing large quantities of the C60 molecule and the subsequent confirmation 8,9 of its cage-like truncated-icosahedral structure 1.  The C70 molecule prepared by the same method was later also isolated and found to have the predicted cylindrical (D5h) structure. Incomplete chromatographic separation of the large molecules C76, C78 and C84 was achieved at the same time 10,11, and small quantities of highly enriched samples were later isolated 12.  Preliminary NMR and spectroscopic studies of these carbon clusters failed, however, to provide evidence for the symmetrical structures predicted earlier 13. Here we report the isolation and characterization of the C76 molecule, a third molecular form of carbon following C60 and C70. We isolated and purified substantial quantities of this species using the extraction technique of ref. 6 together with chromatography. The C-13 NMR spectrum consists of 19 lines of essentially equal intensity, confirming a compact, cage-like fullerene structure. Among the several thousand possible structures for C76, theoretical calculations by Manolopolous 14 predict a chiral structure with D2 symmetry, consisting of a spiralling, double-helical arrangement of edge-sharing pentagons and hexagons. Our NMR spectrum is uniquely consistent with this remarkable structure.
C1 UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024.
C3 University of California System; University of California Los Angeles
NR 23
TC 399
Z9 415
U1 0
U2 68
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 149
EP 153
DI 10.1038/353149a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100048
DA 2026-03-10
ER

PT J
AU WONG, P
AF WONG, P
TI CONTROLLING LABORATORY VIBRATIONS
SO NATURE
LA English
DT Article
RP WONG, P (corresponding author), NEWPORT BIOINSTRUMENTS,18235 MT BALDY CIRCLE,POB 8020,FOUNTAIN VALLEY,CA 92728, USA.
NR 0
TC 0
Z9 0
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 168
EP 169
DI 10.1038/351168a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500058
DA 2026-03-10
ER

PT J
AU MALLA, PB
   RAVINDRANATHAN, P
   KOMARNENI, S
   ROY, R
AF MALLA, PB
   RAVINDRANATHAN, P
   KOMARNENI, S
   ROY, R
TI INTERCALATION OF COPPER METAL-CLUSTERS IN MONTMORILLONITE
SO NATURE
LA English
DT Article
ID complexes; reduction; catalysts; cations
AB EXPANDABLE layer silicates such as montmorillonite can be converted to efficient heterogeneous catalysts by introducing catalytically active sites or guest species between the layers or on the external surfaces.  Attempts to produce intercalated zero-valent transition-metal particles in layer silicates, by hydrogen reduction for example, have, however, failed:  the layers tend to collapse 1, sometimes followed by deposition of metal particles on the external surfaces 2-4.  Here we describe the successful intercalation of copper metal clusters of 4-5 angstrom in montmorillonite by in situ reduction of Cu2+ ions using ethylene glycol.  These metal-cluster intercalates were stable up to at least 500-degrees-C.  The clusters prop the silicate layers apart, much as metal oxides do in pillared clays 5, and may thus be able to introduce unique catalytic product selectivity through a molecular sieving effect similar to that in cluster-loaded zeolites.  As metal clusters of these dimensions behave very differently from the bulk metal 6, intercalates of this sort may prove to be versatile catalysts.
RP MALLA, PB (corresponding author), PENN STATE UNIV,MAT LAB,UNIVERSITY PK,PA 16802, USA.
NR 22
TC 72
Z9 74
U1 1
U2 52
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 555
EP 557
DI 10.1038/351555a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400054
DA 2026-03-10
ER

PT J
AU WOOD, WB
AF WOOD, WB
TI EVIDENCE FROM REVERSAL OF HANDEDNESS IN C-ELEGANS EMBRYOS FOR EARLY CELL-INTERACTIONS DETERMINING CELL FATES
SO NATURE
LA English
DT Article
ID nematode caenorhabditis-elegans; lineages; glp-1
AB MANY animals with overall bilateral symmetry also exhibit some left-right asymmetries with generally invariant handedness.  Therefore, the left-right embryonic axis must have a consistent polarity, whose origins and subsequent effects on development are not understood (reviewed in ref. 1).  Caenorhabditis elegans exhibits such left-right asymmetries at all developmental stages.  The embryonic cell lineage is asymmetric as well:  although the animal is generally bilaterally symmetric, many of its contralaterally analogous cells arise from different lineages on the two sides of the embryo 2,3.  I accomplished reversal of embryonic handedness by micromanipulation at the 6-cell stage, which resulted in mirror-image but otherwise normal development into healthy, fertile animals with all the usual left-right asymmetries reversed.  This result demonstrates that in the 6-cell embryo the pair of anterior (AB) blastomeres on the right is equivalent to the pair on the left, and that the extensive differences in fates between lineally homologous derivatives of these cells on the two sides of the animals must be dictated by cell interactions, most of which are likely to occur early in embryogenesis.
C1 MRC,MOLEC BIOL LAB,CAMBRIDGE CB2 2QH,ENGLAND.
C3 MRC Laboratory Molecular Biology
RP WOOD, WB (corresponding author), UNIV COLORADO,DEPT MOLEC CELLULAR & DEV BIOL,BOX 347,BOULDER,CO 80309, USA.
NR 18
TC 153
Z9 164
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 536
EP 538
DI 10.1038/349536a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100071
PM 1992354
DA 2026-03-10
ER

PT J
AU IGARASHI, M
   NAGATA, A
   JINNO, S
   SUTO, K
   OKAYAMA, H
AF IGARASHI, M
   NAGATA, A
   JINNO, S
   SUTO, K
   OKAYAMA, H
TI WEE1+-LIKE GENE IN HUMAN-CELLS
SO NATURE
LA English
DT Article
ID high-efficiency transformation; fission yeast; schizosaccharomyces-pombe; human homolog; inducer; dna
AB THE wee1+ gene is a mitotic inhibitor controlling the G2 to M transition of the fission yeast Schizosaccharomyces pombe 1 and encodes a protein kinase with both serine- and tyrosine-phosphorylating activities 2.  We have cloned a human gene (WEE1Hu) similar to wee1+ by transcomplementation of a yeast mutant 3,4.  WEE1Hu encodes a protein homologous to the S. pombe wee1+ and mik1+ (a functionally redundant sibling of wee1+) 5 kinases and effectively rescues a wee1 mutation. We report here that overexpression of WEE1Hu in fission yeast generates very elongated cells as a result of inhibition of the G2-M transition in the cell cycle. In addition, we detected a 3-kilobase-long WEE1Hu messenger RNA in all the human cell lines we examined. We conclude that a wee1+-like gene exists and is expressed in human cells.
C1 OSAKA UNIV,MICROBIAL DIS RES INST,DEPT MOLEC GENET,3-1 YAMADAOKA,SUITA,OSAKA 565,JAPAN.
C3 University of Osaka
NR 16
TC 188
Z9 209
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 80
EP 83
DI 10.1038/353080a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500064
PM 1840647
DA 2026-03-10
ER

PT J
AU MAREAN, CW
   GIFFORDGONZALEZ, D
AF MAREAN, CW
   GIFFORDGONZALEZ, D
TI LATE QUATERNARY EXTINCT UNGULATES OF EAST-AFRICA AND PALEOENVIRONMENTAL IMPLICATIONS
SO NATURE
LA English
DT Article
AB UNGULATE communities of two East African savannas, the Serengeti and Athi-Kapiti Plains, are dominated by wildebeest (Connochaetes taurinus) supplemented by zebra (Equus burchelli), topi (Damaliscus lunatus), hartebeest (Alcelaphus buselaphus), buffalo (Syncerus caffer), eland (Taurotragus oryx) and gazelles (Gazella granti and G. thomsoni) 1-3.  Before this research, little was known of East African large mammal communities in the Late Pleistocene and early to middle Holocene.  We document an extinct impala-sized alcelaphine antelope that is numerically dominant in Late Pleistocene archaeofaunal assemblages from the Athi-Kapiti Plains.  The extinct giant buffalo Pelorovis antiquus is present, and a number of arid-adapted regionally extinct species are common.  The small alcelaphine is rare in northern Tanzania, but regionally extinct arid-adapted species are present in Late Pleistocene deposits.  These data indicate that as recently as 12,000 years ago, the large mammal community structure of East African savannas was very different and dry grasslands and arid-adapted ungulates expanded at least as far south as northern Tanzania during the Last Glacial Maximum.
C1 UNIV CALIF SANTA CRUZ,BOARD STUDIES ANTHROPOL,SANTA CRUZ,CA 95064.
C3 University of California System; University of California Santa Cruz
RP MAREAN, CW (corresponding author), SUNY STONY BROOK,DEPT ANTHROPOL,STONY BROOK,NY 11794, USA.
NR 22
TC 42
Z9 49
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 418
EP 420
DI 10.1038/350418a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200048
DA 2026-03-10
ER

PT J
AU SMYTH, JR
   BELL, DR
   ROSSMAN, GR
AF SMYTH, JR
   BELL, DR
   ROSSMAN, GR
TI INCORPORATION OF HYDROXYL IN UPPER-MANTLE CLINOPYROXENES
SO NATURE
LA English
DT Article
ID eclogites; chemistry; minerals
AB WATER (and hydroxyl, OH) plays an important part in determining the properties of minerals and melts in the Earth's upper mantle. The main hydroxyl-bearing phases found in rocks from the upper mantle, phlogopite and amphibole, are not believed to exist in significant quantities at depth. Some of the less abundant phases found in these rocks contain small amounts of hydrous components 1-3, but do not constitute an important reservoir for water. Traces of hydroxyl have been found in common mantle phases 4-6, but not at concentrations high enough to account for the amount of water thought to be present at depth. An exception is suggested by a report 7 that the pyroxene (omphacite) in an eclogite nodule from the Roberts Victor kimberlite pipe contains up to 1,000 p.p.m. OH. Here we show that some of this hydroxyl is associated with cation vacancies in sodic clinopyroxene, and that these pyroxenes may be an important reservoir for hydrous components in the upper mantle.
C1 CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125.
C3 California Institute of Technology
RP SMYTH, JR (corresponding author), UNIV COLORADO,DEPT GEOL SCI,BOULDER,CO 80309, USA.
NR 16
TC 201
Z9 223
U1 0
U2 32
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 732
EP 735
DI 10.1038/351732a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100059
DA 2026-03-10
ER

PT J
AU ALDOVINI, A
   YOUNG, RA
AF ALDOVINI, A
   YOUNG, RA
TI HUMORAL AND CELL-MEDIATED IMMUNE-RESPONSES TO LIVE RECOMBINANT BCG-HIV VACCINES
SO NATURE
LA English
DT Article
ID helper t-cells; stress proteins; foreign dna; htlv-iii; mycobacteria; virus; expression; protection; infection
AB SEVERAL viral and bacterial live recombinant vaccine vehicles are being developed to produce a new generation of vaccines against a broad spectrum of infectious diseases 1. The human tuberculosis vaccine Mycobacterium bovis bacillus Calmette-Guerin (BCG) 2 has features that make it a particularly attractive live recombinant vaccine vehicle. BCG and other mycobacteria are highly effective adjuvants, and the immune response to mycobacteria has been studied extensively. With nearly two billion immunizations, BCG has a long record of safe use in man 3,4. It is one of the few vaccines that can be given at birth, it engenders long-lived immune responses with only a single dose, and there is a worldwide distribution network with experience in BCG vaccination. Recently developed molecular genetic tools and methods for mycobacteria have provided the means to introduce foreign genes into BCG 5-8. Here we report that a variety of human immunodeficiency virus type 1 polypeptides can be expressed in BCG recombinants under the control of the mycobacterial hsp70 promoter and that the foreign polypeptides produced in BCG can induce antibody and T-cell responses. These results demonstrate that BCG can be used as a live recombinant vaccine vehicle to induce immune responses to pathogen proteins produced by the bacillus.
C1 MIT, DEPT BIOL, CAMBRIDGE, MA 02139 USA.
C3 Massachusetts Institute of Technology (MIT)
RP ALDOVINI, A (corresponding author), WHITEHEAD INST BIOMED RES, 9 CAMBRIDGE CTR, CAMBRIDGE, MA 02142 USA.
NR 28
TC 285
Z9 338
U1 0
U2 7
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 479
EP 482
DI 10.1038/351479a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800055
PM 2046750
DA 2026-03-10
ER

PT J
AU RITLAND, DB
   BROWER, LP
AF RITLAND, DB
   BROWER, LP
TI THE VICEROY BUTTERFLY IS NOT A BATESIAN MIMIC
SO NATURE
LA English
DT Article
ID monarch butterfly; pyrrolizidine alkaloids; similarity; lepidoptera; nymphalidae; spectrum
AB DEFENSIVE mimicry has long been a paradigm of adaptive evolution by natural selection 1-3.  Mimics, models and predators in a batesian mimicry system (unpalatable model, palatable mimic) exist in a very different selective milieu from those in a mullerian system (involving greater-than-or-equal-to 2 unpalatable 'co-models') 1,4-6. Consequently, the incorrect characterization of a mimicry relationship obscures the natural histories of populations involved and undermines attempts to test general mimicry theory by means of empirical studies of specific systems.  Here, we reassess the classic case of mimicry involving viceroy butterflies, Limenitis archippus (Cramer) (Nymphalidae), and two species they purportedly mimic:  the monarch, Danaus plexippus (L.), and the queen, Danaus gilippus (Cramer) (Nymphalidae:  Danainae).  Viceroys are historically considered palatable (batesian) mimics 7,8 of the chemically defended 9 danaines. Our experiment refutes this interpretation by revealing that viceroys are as unpalatable as monarchs, and significantly more unpalatable than queens from representative Florida populations.  This implies that viceroys are mullerian co-mimics of the danaines and prompts a comprehensive reassessment of this widely cited exemplar of mimicry.
RP RITLAND, DB (corresponding author), UNIV FLORIDA,DEPT ZOOL,GAINESVILLE,FL 32611, USA.
NR 27
TC 75
Z9 92
U1 4
U2 93
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 497
EP 498
DI 10.1038/350497a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300049
DA 2026-03-10
ER

PT J
AU STEWART, LMD
   HIRST, M
   FERBER, ML
   MERRYWEATHER, AT
   CAYLEY, PJ
   POSSEE, RD
AF STEWART, LMD
   HIRST, M
   FERBER, ML
   MERRYWEATHER, AT
   CAYLEY, PJ
   POSSEE, RD
TI CONSTRUCTION OF AN IMPROVED BACULOVIRUS INSECTICIDE CONTAINING AN INSECT-SPECIFIC TOXIN GENE
SO NATURE
LA English
DT Article
ID androctonus-australis hector; nuclear polyhedrosis-virus; expression vectors; bacillus-thuringiensis; cells; venom
AB BACULOVIRUSES provide alternatives to chemicals for controlling insect pests 1-4 and can be applied by spraying. Baculoviruses have a limited host range, but work relatively slowly. They are dissolved in the midgut of insect larvae to release infectious virions which enter gut epithelial cells and begin to replicate. Replication in other organs causes extensive tissue damage and eventually death. This process can take 4-5 days, but in the field may last for more than a week, allowing the larvae to feed for longer and thereby damaging the host plant. Baculovirus expression vectors expreSSing foreign genes 5,6, such as those for insect-specific toxins, hormones or enzymes, might alleviate this problem 7-11. We have now constructed a recombinant baculovirus derived from Autographa californica nuclear polyhedrosis virus containing an insect-specific neurotoxin from the venom of the North African (Algerian) scorpion, Androctonus australis Hector 12. The neurotoxin acts by causing specific modifications to the Na+ conductance of neurons, producing a presynaptic excitatory effect leading to paralysis and death 15,16; it has no effect in mice 17,18. Expression of the neurotoxin by the virus causes a reduction in the time required to kill the host insect.
C1 WELLCOME ENVIRONM HLTH,BERKHAMSTED HP4 2DY,HERTS,ENGLAND.
C3 GlaxoSmithKline; Glaxosmithkline United Kingdom
RP STEWART, LMD (corresponding author), NERC,INST VIROL & ENVIRONM MICROBIOL,MANSFIELD RD,OXFORD OX1 3SR,ENGLAND.
NR 30
TC 309
Z9 364
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 85
EP 88
DI 10.1038/352085a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800078
PM 2062383
DA 2026-03-10
ER

PT J
AU LIDDINGTON, RC
   YAN, Y
   MOULAI, J
   SAHLI, R
   BENJAMIN, TL
   HARRISON, SC
AF LIDDINGTON, RC
   YAN, Y
   MOULAI, J
   SAHLI, R
   BENJAMIN, TL
   HARRISON, SC
TI STRUCTURE OF SIMIAN VIRUS-40 AT 3.8-A RESOLUTION
SO NATURE
LA English
DT Article
ID bushy stunt virus; simple spherical virus; major capsid protein; common cold virus; polyoma-virus; subunit association; multiple-modes; invitro; cells; vp1
AB The crystallographically determined structure of simian virus 40 shows that the 72 pentamers of viral protein VP1, which form the outer shell, have identical conformations except for the C-terminal arms of their subunits. Five arms emerge from each pentamer and insert into neighbouring pentamers. This tying together of standard building blocks allows for the required variability in packing geometry without sacrificing specificity.
C1 HARVARD UNIV,HOWARD HUGHES MED INST,CAMBRIDGE,MA 02138.
   HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,CAMBRIDGE,MA 02138.
   HARVARD UNIV,SCH MED,DEPT PATHOL,BOSTON,MA 02115.
C3 Howard Hughes Medical Institute; Harvard University; Harvard University; Harvard University; Harvard Medical School
NR 42
TC 590
Z9 648
U1 0
U2 36
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 278
EP 284
DI 10.1038/354278a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400038
PM 1659663
DA 2026-03-10
ER

PT J
AU MITCHELL, MJ
   WOODS, DR
   TUCKER, PK
   OPP, JS
   BISHOP, CE
AF MITCHELL, MJ
   WOODS, DR
   TUCKER, PK
   OPP, JS
   BISHOP, CE
TI HOMOLOGY OF A CANDIDATE SPERMATOGENIC GENE FROM THE MOUSE Y-CHROMOSOME TO THE UBIQUITIN-ACTIVATING ENZYME-E1
SO NATURE
LA English
DT Article
ID sex-determining region; l-cell defect; insitu hybridization; dna-replication; mice; localization; expression; antigen; differentiation; sequences
AB THE Sxr (sex-reversed) region, a fragment of the Y chromosome short arm, can cause chromosomally female XXSxr or XSxrO mice to develop as sterile males 1-3. The original Sxr region, termed Sxr(a), encodes:  Tdy, the primary sex-determining gene; Hya, the controlling or structural locus for the minor transplantation antigen H-Y (ref. 4); gene(s) controlling the expression of the serologically detected male antigen (SDMA) 5; Spy, a gene(s) required for the survival and proliferation of A spermatogonia during spermatogenesis 6,7; Zfy-1/Zfy-2, zinc-finger-containing genes of unknown function 8; and Sry, which is probably identical to Tdy (ref. 9). A deletion variant 10 of Sxr(a), termed Sxr(b), which lacks Hya, SDMA expression, Spy and some Zfy-2 sequences, makes positional cloning of these genes possible. We report here the isolation of a new testis-specific gene, Sby, mapping to the DNA deleted from the Sxr(b) region (the DELTA-Sxr(b) interval). Sby has extensive homology to the X-linked human ubiquitin-activating enzyme E1 (ref. 11). The critical role of this enzyme in nuclear DNA replication 12 together with the testis-specific expression of Sby suggests Sby as a candidate for the spermatogenic gene Spy.
C1 INST PASTEUR,INSERM,U276,UNITE IMMUNOGENET HUMAINE,PARIS 15,FRANCE.
   UNIV MICHIGAN,MUSEUM ZOOL,ANN ARBOR,MI 48109.
   UNIV MICHIGAN,DEPT BIOL,ANN ARBOR,MI 48109.
C3 Pasteur Network; Universite Paris Cite; Institut Pasteur Paris; Institut National de la Sante et de la Recherche Medicale (Inserm); University of Michigan System; University of Michigan; University of Michigan System; University of Michigan
RP MITCHELL, MJ (corresponding author), UNIV TENNESSEE,DEPT OBSTET GYNECOL,DIV REPROD GENET,MOLEC GENET RES LAB,MEMPHIS,TN 38105, USA.
NR 33
TC 150
Z9 164
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 483
EP 486
DI 10.1038/354483a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800062
PM 1684224
DA 2026-03-10
ER

PT J
AU BIKOFF, EK
   JAFFE, L
   RIBAUDO, RK
   OTTEN, GR
   GERMAIN, RN
   ROBERTSON, EJ
AF BIKOFF, EK
   JAFFE, L
   RIBAUDO, RK
   OTTEN, GR
   GERMAIN, RN
   ROBERTSON, EJ
TI MHC CLASS-I SURFACE EXPRESSION IN EMBRYO-DERIVED CELL-LINES INDUCIBLE WITH PEPTIDE OR INTERFERON
SO NATURE
LA English
DT Article
ID major histocompatibility complex; carcinoma-cells; gene-expression; mouse; antigen; beta-2-microglobulin; transcripts; molecules; placenta; vector
AB IT has long been recognized that the absence of expression of products of the major histocompatibility complex (MHC) during early development might allow the fetus to escape recognition by maternal lymphocytes. In addition to the MHC class I heavy chain and beta-2-microglobulin, antigenic peptide is an essential structural component of the class I molecule 1-5.  Indeed, there is evidence that MHC-linked genes encoding peptide transporter molecules 6-10 and possibly components of a proteolytic complex 11,12 are necessary for MHC class I assembly and stability at the cell surface. Here we demonstrate that embryonic cells in general show a defect in MHC class I assembly. Surface expression was rescued in the presence of an appropriate antigenic peptide, or by treatment with interferon. Consistent with this, HAM1 (ref. 9) messenger RNA was not constitutively expressed, but was inducible by interferon, and during differentiation in vitro. Thus, tolerance of the fetal allograft may in part be controlled at the level of peptide-dependent MHC class I assembly.
C1 NIAID,IMMUNOL LAB,BETHESDA,MD 20892.
   COLUMBIA UNIV COLL PHYS & SURG,DEPT GENET & DEV,NEW YORK,NY 10032.
C3 National Institutes of Health (NIH) - USA; NIH National Institute of Allergy & Infectious Diseases (NIAID); Columbia University
RP BIKOFF, EK (corresponding author), CUNY MT SINAI SCH MED,DEPT OBSTET GYNECOL & REPROD SCI,NEW YORK,NY 10029, USA.
NR 30
TC 57
Z9 61
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 235
EP 238
DI 10.1038/354235a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800051
PM 1720508
DA 2026-03-10
ER

PT J
AU HAN, HQ
   NICHOLS, RA
   RUBIN, MR
   BAHLER, M
   GREENGARD, P
AF HAN, HQ
   NICHOLS, RA
   RUBIN, MR
   BAHLER, M
   GREENGARD, P
TI INDUCTION OF FORMATION OF PRESYNAPTIC TERMINALS IN NEUROBLASTOMA-CELLS BY SYNAPSIN-IIB
SO NATURE
LA English
DT Article
ID glioma hybrid-cells; phosphoprotein; protein-1
AB THE synapsins are a family of closely related phosphoproteins (termed synapsins Ia, Ib, IIa and IIb) associated with synaptic vesicles and implicated in the short-term regulation of neurotransmitter release from nerve endings 1-5.  During development, expression of the synapsins correlates temporally with synapse formation 6, but there has been no direct evidence that they are involved in synaptogenesis.  Here we report that overexpression of synapsin IIb in the neuroblastoma x glioma hybrid clonal cell line NG108-15 leads, during cell differentiation, to marked increases in the number of neuritic varicosities and in the numbers of small clear vesicles and large dense core vesicles per varicosity, as well as to the appearance of synapse-like cell-cell contacts.  Thus, synapsin IIb may be involved in the regulation of synapse formation and, as a result, in long-term neuronal signalling.
RP HAN, HQ (corresponding author), ROCKEFELLER UNIV,MOLEC & CELLULAR NEUROSCI LAB,1230 YORK AVE,NEW YORK,NY 10021, USA.
NR 20
TC 163
Z9 171
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 697
EP 700
DI 10.1038/349697a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700048
PM 1899916
DA 2026-03-10
ER

PT J
AU LINGNER, J
   KELLERMANN, J
   KELLER, W
AF LINGNER, J
   KELLERMANN, J
   KELLER, W
TI CLONING AND EXPRESSION OF THE ESSENTIAL GENE FOR POLY(A) POLYMERASE FROM SACCHAROMYCES-CEREVISIAE
SO NATURE
LA English
DT Article
ID binding-protein; yeast; identification; sequence; invitro; motifs
AB POLY(A) polymerase is essential for the maturation of messenger RNA, adding tracts of adenosine residues to the 3' end of precursor RNA generated by endonucleolytic cleavage. This mechanism of MRNA 3' processing seems to be similar in yeast and in higher eucaryotes 1, although there are differences in the recognition signals in the pre-mRNA 2. Here we describe the cloning of the gene for yeast poly(A) polymerase. The enzyme is encoded by a single and essential gene located near the centromere on the left arm of chromosome 11. Poly(A) polymerase purified from recombinant Escherichia coli has the same physical and biochemical properties as the yeast enzyme. The yeast poly(A) polymerase shares features of sequence with its mammalian homologue 3,4.
C1 MAX PLANCK INST BIOCHEM, GENZENTRUM, W-8033 MARTINSRIED, GERMANY.
C3 Max Planck Society
RP LINGNER, J (corresponding author), UNIV BASEL, BIOZENTRUM, DEPT CELL BIOL, CH-4056 BASEL, SWITZERLAND.
NR 30
TC 116
Z9 124
U1 0
U2 3
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 496
EP 498
DI 10.1038/354496a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800066
PM 1840648
DA 2026-03-10
ER

PT J
AU KNILL, DC
   KERSTEN, D
AF KNILL, DC
   KERSTEN, D
TI APPARENT SURFACE CURVATURE AFFECTS LIGHTNESS PERCEPTION
SO NATURE
LA English
DT Article
ID illumination; information
AB THE human visual system has the remarkable capacity to perceive accurately the lightness, or relative reflectance, of surfaces, even though much of the variation in image luminance may be caused by other scene attributes, such as shape and illumination.  Most physiological 1,2, and computational models 3-6 of lightness perception invoke early sensory mechanisms that act independently of, or before, the estimation of other scene attributes.  In contrast to the modularity of lightness perception assumed in these models are experiments that show that supposedly 'higher-order' percepts of planar surface attributes, such as orientation, depth and transparency 7-10, can influence perceived lightness.  Here we show that perceived surface curvature can also affect perceived lightness.  The results of the earlier experiments indicate that perceiving luminance edges as changes in surface attributes other than reflectance can influence lightness.  These results suggest that the interpretation of smooth variations in luminance can also affect lightness percepts.
RP KNILL, DC (corresponding author), UNIV MINNESOTA,DEPT PSYCHOL,MINNEAPOLIS,MN 55455, USA.
NR 16
TC 172
Z9 186
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 228
EP 230
DI 10.1038/351228a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000055
PM 2041568
DA 2026-03-10
ER

PT J
AU BERRY, MJ
   BANU, L
   LARSEN, PR
AF BERRY, MJ
   BANU, L
   LARSEN, PR
TI TYPE-I IODOTHYRONINE DEIODINASE IS A SELENOCYSTEINE-CONTAINING ENZYME
SO NATURE
LA English
DT Article
ID selenium glutathione-peroxidase; protein disulfide isomerase; rat-liver; nucleotide-sequence; active-site; expression; thyroxine; triiodothyronine; inhibition; deficiency
AB ALTHOUGH thyroxine (3,5,3',5'-tetraiodonthyroine, T4) is the principal secretory product of the vertebrate thyroid, its essential metabolic and developmental effects are all mediated by 3,5,3'-triiodothyronine (T3), which is produced from the prohormone by 5'-deiodination.  The type-I iodothyronine deiodinase, a thiol-requiring propylthiouracil-sensitive oxidoreductase, is found mainly in liver and kidney and provides most of the circulating T3(1) but so far this enzyme has not been purified. Using expression cloning in the Xenopus oocyte, we have isolated a 2.1-kilobase complementary DNA of this deiodinase from a rat liver cDNA library.  The kinetic properties of the protein expressed in transient assay systems, the tissue distribution of the messenger RNA, and its changes with thyroid status, all confirm its identity.  We find that the mRNA for this enzyme contains a UGA codon for selenocysteine which is necessary for maximal enzyme activity.  This explains why conversion to T4 to T3 is impaired in experimental selenium deficiency 2-6 and identifies an essential role for this trace element in thyroid hormone action.
C1 BRIGHAM & WOMENS HOSP,DEPT MED,DIV THYROID,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,BOSTON,MA 02115.
C3 Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical School
RP BERRY, MJ (corresponding author), BRIGHAM & WOMENS HOSP,DEPT MED,HOWARD HUGHES MED INST LAB,75 FRANCIS ST,BOSTON,MA 02115, USA.
NR 31
TC 831
Z9 889
U1 0
U2 35
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 438
EP 440
DI 10.1038/349438a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400059
PM 1825132
DA 2026-03-10
ER

PT J
AU BEZPROZVANNY, I
   WATRAS, J
   EHRLICH, BE
AF BEZPROZVANNY, I
   WATRAS, J
   EHRLICH, BE
TI BELL-SHAPED CALCIUM-RESPONSE CURVES OF INS(1,4,5)P3-GATED AND CALCIUM-GATED CHANNELS FROM ENDOPLASMIC-RETICULUM OF CEREBELLUM
SO NATURE
LA English
DT Article
ID inositol 1,4,5-trisphosphate receptor; muscle sarcoplasmic-reticulum; pancreatic acinar-cells; smooth-muscle; trisphosphate receptor; single channel; adenine-nucleotides; release channel; skeletal-muscle; ca-2+ release
AB RELEASE of calcium from intracellular stores occurs by two pathways, an inositol 1,4,5-trisphosphate (InsP3)-gated channel 1-3 and a calcium-gated channel (ryanodine receptor) 4-6. Using specific antibodies, both receptors were found in Purkinje cells of cerebellum 7,8. We have now Compared the functional properties of the channels corresponding to the two receptors by incorporating endoplasmic reticulum vesicles from canine cerebellum into planar bilayers. InsP3-gated channels were observed most frequently. Another channel type was activated by adenine nucleotides or caffeine, inhibited by ruthenium red, and modified by ryanodine, characteristics of the ryanodine receptor/channel 6. The open probability of both channel types displayed a bell-shaped curve for dependence on calcium. For the InsP3-gated channel, the maximum probability of opening occurred at 0.2-mu-M free calcium, with sharp decreases on either side of the maximum. Maximum activity for the ryanodine receptor/channel was maintained between 1 and 100-mu-M calcium. Thus, within the physiological range of cytoplasmic calcium, the InsP3-gated channel itself allows positive feedback and then negative feedback for calcium release, whereas the ryanodine receptor/channel behaves solely as a calcium-activated channel. The existence in the same cell of two channels with different responses to calcium and different ligand sensitivities provides a basis for complex patterns of intracellular calcium regulation.
C1 UNIV CONNECTICUT, CTR HLTH, DEPT MED, FARMINGTON, CT 06032 USA.
   UNIV CONNECTICUT, CTR HLTH, DEPT PHYSIOL, FARMINGTON, CT 06032 USA.
   ACAD SCI USSR, INST CYTOL, LENINGRAD 194064, USSR.
C3 University of Connecticut; University of Connecticut; Russian Academy of Sciences
NR 35
TC 1611
Z9 1753
U1 0
U2 61
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 751
EP 754
DI 10.1038/351751a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100066
PM 1648178
DA 2026-03-10
ER

PT J
AU TURNLEY, AM
   MORAHAN, G
   OKANO, H
   BERNARD, O
   MIKOSHIBA, K
   ALLISON, J
   BARTLETT, PF
   MILLER, JFAP
AF TURNLEY, AM
   MORAHAN, G
   OKANO, H
   BERNARD, O
   MIKOSHIBA, K
   ALLISON, J
   BARTLETT, PF
   MILLER, JFAP
TI DYSMYELINATION IN TRANSGENIC MICE RESULTING FROM EXPRESSION OF CLASS-I HISTOCOMPATIBILITY MOLECULES IN OLIGODENDROCYTES
SO NATURE
LA English
DT Article
ID pancreatic beta-cells; myelin basic-protein; multiple-sclerosis; mhc molecules; schwann-cells; antigens; tolerance; gene; transcription; interferon
AB MAJOR histocompatibility complex (MHC) molecules are not normally expressed in the central nervous system (CNS) 1-3.  However, aberrant expression has been observed in multiple sclerosis lesions and could contribute to the destruction of myelin or the myelinating cells known as oligodendrocytes 4,5.  The mechanism of cell damage associated with aberrant MHC molecule expression is unclear:  for example, overexpression of class I (ref. 6) and class II (refs 7, 8) MHC molecules in pancreatic beta-cells in transgenic mice leads to nonimmune destruction of the cells and insulin-dependent diabetes mellitus.  We have generated transgenic mice that express class I H-2K(b) MHC molecules, under the control of the myelin basic protein promoter, specifically in oligodendrocytes.  Homozygous transgenic mice have a shivering phenotype, develop tonic seizures and die at 15-22 days.  This phenotype, which we term 'wonky', is due to hypomyelination in the CNS, and not to involvement of the immune system.  The primary defect appears to be a shortage of myelinating oligodendrocytes resulting from overexpression of the class I MHC molecules.
C1 OSAKA UNIV,INST PROT RES,OSAKA 565,JAPAN.
C3 University of Osaka
RP TURNLEY, AM (corresponding author), ROYAL MELBOURNE HOSP,WALTER & ELIZA HALL INST MED RES,PO ROYAL MELBOURNE HOSP,PARKVILLE,VIC 3050,AUSTRALIA.
NR 26
TC 108
Z9 115
U1 1
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 566
EP 569
DI 10.1038/353566a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300070
PM 1717849
DA 2026-03-10
ER

PT J
AU STEINMEYER, K
   KLOCKE, R
   ORTLAND, C
   GRONEMEIER, M
   JOCKUSCH, H
   GRUNDER, S
   JENTSCH, TJ
AF STEINMEYER, K
   KLOCKE, R
   ORTLAND, C
   GRONEMEIER, M
   JOCKUSCH, H
   GRUNDER, S
   JENTSCH, TJ
TI INACTIVATION OF MUSCLE CHLORIDE CHANNEL BY TRANSPOSON INSERTION IN MYOTONIC MICE
SO NATURE
LA English
DT Article
ID recessive generalized myotonia; mouse mutant adr; sequence; etn; conductance; expression; protein; rat
AB MYOTONIA (stiffness and impaired relaxation of skeletal muscle) is a symptom of several diseases caused by repetitive firing of action potentials in muscle membranes 1. Purely myotonic human diseases are dominant myotonia congenita (Thomsen) and recessive generalized myotonia (Becker), whereas myotonic dystrophy is a systemic disease. Muscle hyperexcitability was attributed to defects in sodium channels 2,3 and/or to a decrease in chloride conductance (in Becker's myotonia 4 and in genetic animal models 5-10). Experimental blockage of Cl- conductance (normally 70-85% of resting conductance in muscle") in fact elicits myotonia 1,9. ADR (ref. 12) mice are a realistic animal model 5-7,12-18 for recessive autosomal myotonia. In addition to Cl- conductance 5, many other parameters 6,12,16 are changed in muscles of homozygous animals. We have now cloned the major mammalian skeletal muscle chloride channel (ClC-1) 19. Here we report that in ADR mice a transposon of the ETn family 20-23 has inserted into the corresponding gene, destroying its coding potential for several membrane-spanning domains. Together with the lack of recombination between the Clc-1 gene and the adr locus, this strongly suggests a lack of functional chloride channels as the primary cause of mouse myotonia.
C1 UNIV HAMBURG,CTR MOLEC NEUROBIOL,MARTINISTR 52,W-2000 HAMBURG 20,GERMANY.
   UNIV BIELEFELD,DEV BIOL UNIT,W-4800 BIELEFELD 1,GERMANY.
C3 University of Hamburg; University of Bielefeld
NR 35
TC 329
Z9 351
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 304
EP 308
DI 10.1038/354304a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400047
PM 1659665
DA 2026-03-10
ER

PT J
AU HENNECKE, F
   KOLMAR, H
   BRUNDL, K
   FRITZ, HJ
AF HENNECKE, F
   KOLMAR, H
   BRUNDL, K
   FRITZ, HJ
TI THE VSR GENE-PRODUCT OF ESCHERICHIA-COLI K-12 IS A STRAND-SPECIFIC AND SEQUENCE-SPECIFIC DNA MISMATCH ENDONUCLEASE
SO NATURE
LA English
DT Article
ID short patch repair; escherichia-coli; polymerase-i; lambda; 5-methyl-cytosine; recombination; methylation; glycosylase; repressor; mechanism
AB IN Escherichia coli K-12, the Dcm methyltransferase catalyses methylation of the inner cytosine residue in the sequence CC(A)/(T)GG 1,2. Hydrolytic deamination of 5-methylcytosine bases in DNA leads to thymine residues, and hence to T/G mismatches, pre-mutagenic DNA lesions consisting of two natural DNA constituents and thus devoid of an obvious marker of the damaged DNA strand. These mismatches are corrected by the VSP repair pathway, which is characterized by very short patches of DNA repair synthesis 3,4. It depends on genes vsr 5 and polA 6 and is strongly stimulated by mutL and mutS 7-9. The vsr gene product (Vsr; M(r) 18,000) was purified and characterized as a DNA mismatch endonuclease, a unique and hitherto unknown type of enzyme. Vsr endonuclease nicks double-stranded DNA within the sequence CT(A)/(T)GN or NT(A)/(T)GG next to the underlined thymidine residue, which is mismatched to 2'-deoxyguanosine. The incision is mismatch-dependent and strand-specific. These results illustrate how Vsr endonuclease initiates VSP mismatch repair.
RP HENNECKE, F (corresponding author), UNIV GOTTINGEN,INST MOLEK GENET,GRISEBACHSTR 8,W-3400 GOTTINGEN,GERMANY.
NR 26
TC 132
Z9 138
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 776
EP 778
DI 10.1038/353776a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600075
PM 1944537
DA 2026-03-10
ER

PT J
AU FALKOWSKI, PG
   ZIEMANN, D
   KOLBER, Z
   BIENFANG, PK
AF FALKOWSKI, PG
   ZIEMANN, D
   KOLBER, Z
   BIENFANG, PK
TI ROLE OF EDDY PUMPING IN ENHANCING PRIMARY PRODUCTION IN THE OCEAN
SO NATURE
LA English
DT Article
ID photosynthetic energy-conversion; pacific-ocean; fluxes; growth
AB IN steady-state models of primary production in the open ocean, the upward fluxes of nutrients are balanced by the export of particulate production to the ocean depths. Export production represents the biological effect of carbon production on the net exchange of carbon dioxide between the atmosphere and the ocean. Geochemical estimates of exported production, based on calculations of rates of oxygen usage 1 or heat fluxes 2 are two to three times as high as those determined from biological measurements 3-5. One possible explanation for the differing estimates is that export production, calculated from independent geochemical signals, is too high. Another is that biological measurements severely undersample episodic nutrient injections into the photic zone 1,4. Eddy pumping represents one of the possible mechanisms of nutrient injection 1. Here we examine the enhancement of production by a cyclonic eddy in the subtropical Pacific with instrumentation that allows us to overcome the sampling problem. Our results reveal that eddy pumping markedly stimulates primary production, and that phytoplankton in the upper oligotrophic ocean outside the eddy are not growing near their maximum relative specific growth rates. But if the relative enhancement of production is typical, our results suggest that eddy pumping would enhance total primary production by only approximately 20%.
C1 OCEAN INST,WAIMANALO,HI 96795.
RP FALKOWSKI, PG (corresponding author), BROOKHAVEN NATL LAB,DIV OCEANOG & ATMOSPHER SCI,UPTON,NY 11973, USA.
NR 17
TC 547
Z9 589
U1 2
U2 120
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 55
EP 58
DI 10.1038/352055a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800067
DA 2026-03-10
ER

PT J
AU ROJAS, CV
   WANG, JZ
   SCHWARTZ, LS
   HOFFMAN, EP
   POWELL, BR
   BROWN, RH
AF ROJAS, CV
   WANG, JZ
   SCHWARTZ, LS
   HOFFMAN, EP
   POWELL, BR
   BROWN, RH
TI A MET-TO-VAL MUTATION IN THE SKELETAL-MUSCLE NA+ CHANNEL ALPHA-SUBUNIT IN HYPERKALEMIC PERIODIC PARALYSIS
SO NATURE
LA English
DT Article
ID sodium-channel; cdna sequence; rat-brain; gene; expression; drosophila
AB HYPERKALAEMIC periodic paralysis (HYPP) 1 is an autosomal dominant disease that results in episodic electrical inexcitability and paralysis of skeletal muscle. Electrophysiological data indicate that tetrodotoxin-sensitive sodium channels from muscle cells of HYPP-affected individuals show abnormal inactivation 2,3. Genetic analysis of nine HYPP families has shown tight linkage between the adult skeletal muscle sodium channel alpha-subunit gene on chromosome 17q and the disease (lod score, z = 24; recombination frequency theta = 0) 4-6, strongly suggesting that mutations of the alpha-subunit gene cause HYPP. We sequenced the alpha-subunit coding region isolated from muscle biopsies from affected (familial HYPP) and control individuals by cross-species polymerase chain reaction-mediated complementary DNA cloning. We have identified an A --> G substitution in the patient's messenger RNA that causes a Met --> Val change in a highly conserved region of the alpha-subunit, predicted to be in a transmembrane domain. This same change was found in a sporadic case of HYPP as a new mutation. We have therefore discovered a voltage-gated channel mutation responsible for a human genetic disease.
C1 UNIV PITTSBURGH,SCH MED,DEPT MOLEC GENET & BIOCHEM,PITTSBURGH,PA 15261.
   UNIV PITTSBURGH,SCH MED,DEPT HUMAN GENET,PITTSBURGH,PA 15261.
   UNIV PITTSBURGH,SCH MED,DEPT PEDIAT,PITTSBURGH,PA 15261.
   OREGON HLTH SCI UNIV,PEDIAT METAB LAB,PORTLAND,OR 97201.
C3 Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; Oregon Health & Science University
NR 24
TC 317
Z9 334
U1 1
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 387
EP 389
DI 10.1038/354387a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100049
PM 1659668
DA 2026-03-10
ER

PT J
AU WALTER, RC
   MANEGA, PC
   HAY, RL
   DRAKE, RE
   CURTIS, GH
AF WALTER, RC
   MANEGA, PC
   HAY, RL
   DRAKE, RE
   CURTIS, GH
TI LASER-FUSION 40AR/39AR DATING OF BED-I, OLDUVAI-GORGE, TANZANIA
SO NATURE
LA English
DT Article
ID age; calibration; event; kenya
AB BED I of Olduvai Gorge has yielded some of the most important hominid fossils in the world, but precise age estimates have been elusive. Here we report new dating results for Bed I, based on 40Ar/AR-39 analyses of single mineral grains using the laser-fusion technique. These dates reveal that the fossiliferous deposits of middle to upper Bed I, a period of significant biological and climatic change, comprise an extremely brief interval of time, from 1.80 Myr to 1.75 Myr. Dates for lower Bed I suggest that the base of the Olduvai subchron, of the geomagnetic polarity timescale, may be around 100,000 yr older than the currently accepted value.
C1 UNIV COLORADO, DEPT GEOL, BOULDER, CO 80309 USA.
   UNIV COLORADO, INSTAAR, BOULDER, CO 80309 USA.
   UNIV ILLINOIS, DEPT GEOL, URBANA, IL 61801 USA.
C3 University of Colorado System; University of Colorado Boulder; University of Colorado System; University of Colorado Boulder; University of Illinois System; University of Illinois Urbana-Champaign
RP WALTER, RC (corresponding author), INST HUMAN ORIGINS, CTR GEOCHRONOL, 2453 RIDGE RD, BERKELEY, CA 94709 USA.
NR 28
TC 112
Z9 122
U1 0
U2 6
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 145
EP 149
DI 10.1038/354145a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000059
DA 2026-03-10
ER

PT J
AU PEREZMUNUZURI, V
   ALIEV, R
   VASIEV, B
   PEREZVILLAR, V
   KRINSKY, VI
AF PEREZMUNUZURI, V
   ALIEV, R
   VASIEV, B
   PEREZVILLAR, V
   KRINSKY, VI
TI SUPER-SPIRAL STRUCTURES IN AN EXCITABLE MEDIUM
SO NATURE
LA English
DT Article
ID chemical activity; waves; circulation
AB ROTATING spiral waves have been observed in various excitable media, including heart muscle 1, retinae 2, cultures of the slime mould Dyctiostelium discoideum 3,4 and chemical oscillators such as the Belousov-Zhabotinsky (BZ) reaction 5-7. Under certain conditions the spiral wave does not exhibit simple periodic rotation, but quasiperiodic 8 (or 'compound' 9) rotation, in which the spiral's origin (the tip) meanders 10. Recent calculations 11 have shown that highly meandering tip motion can impose superstructures on spiral waves. Here we reproduce these patterns experimentally, using the BZ reaction as the excitable medium. We induce high tip meander by applying pulses of electrical current locally at the tip 12. Image processing of the patterns reveals a spiral wave of larger wavelength superimposed on the original wave, an effect that can be described in terms of a Doppler shift in the original spiral.
C1 UNIV SANTIAGO COMPOSTELA,FAC FIS,DEPT FIS MAT CONDENSADA,E-15706 SANTIAGO,SPAIN.
C3 Universidade de Santiago de Compostela
RP PEREZMUNUZURI, V (corresponding author), ACAD SCI USSR,INST THEORET & EXPTL BIOPHYS,PUSHCHINO 142292,USSR.
NR 17
TC 88
Z9 94
U1 4
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 740
EP 742
DI 10.1038/353740a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600063
DA 2026-03-10
ER

PT J
AU GILBERT, JS
   LANE, SJ
   SPARKS, RSJ
   KOYAGUCHI, T
AF GILBERT, JS
   LANE, SJ
   SPARKS, RSJ
   KOYAGUCHI, T
TI CHARGE MEASUREMENTS ON PARTICLE FALLOUT FROM A VOLCANIC PLUME
SO NATURE
LA English
DT Article
ID mount-st-helens; eruptions; tephra; deposition
AB THE aggregation of fine ash particles has an important role in controlling the deposition of widely dispersed volcanic ash.  Here we report measurements of electrical charge on ash particles falling from the eruption columns of Sakurajima volcano in Japan. Absolute charge to mass (q/m) ratios ranged from +3 to +6x10(-4) C kg-1 and from -2 to -5x10(-4) C kg-1.  The average q/m ratio ranged from +2 to +5x10(-5) C kg-1.  The generation of electrostatic charge may result from triboelectric effects in the plume, or from fracture-induced charging.  Charge on ash particles provides attractive forces large enough to cause the aggregation of smaller particles and the adhesion of dust to larger particles.  Particle aggregation may explain the polymodal grain-size distributions commonly found in ash-fall deposits, and the proximal deposition of fine ash, as well as the distal deposition of coarse particles in these deposits.  Our data suggest that electrostatic effects greatly influence the dispersal and deposition of ash during explosive volcanic eruptions.
C1 KUMAMOTO UNIV,FAC SCI,DEPT GEOL,KUMAMOTO 860,JAPAN.
C3 Kumamoto University
RP GILBERT, JS (corresponding author), UNIV BRISTOL,DEPT GEOL,WILLS MEM BLDG,QUEENS RD,BRISTOL BS8 1RJ,ENGLAND.
NR 19
TC 112
Z9 121
U1 0
U2 36
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 598
EP 600
DI 10.1038/349598a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000055
DA 2026-03-10
ER

PT J
AU DAVIES, K
AF DAVIES, K
TI HUMAN-GENETICS - BREAKING THE FRAGILE-X
SO NATURE
LA English
DT Article
ID expression
NR 11
TC 7
Z9 7
U1 1
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 439
EP 440
DI 10.1038/351439a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800025
PM 1646399
DA 2026-03-10
ER

PT J
AU BAKER, VR
   STROM, RG
   GULICK, VC
   KARGEL, JS
   KOMATSU, G
   KALE, VS
AF BAKER, VR
   STROM, RG
   GULICK, VC
   KARGEL, JS
   KOMATSU, G
   KALE, VS
TI ANCIENT OCEANS, ICE SHEETS AND THE HYDROLOGICAL CYCLE ON MARS
SO NATURE
LA English
DT Article
ID small martian valleys; morphology; water; evolution; history; origin; earth; features; climate; release
AB A variety of anomalous geomorphological features on Mars can be explained by a conceptual scheme involving episodic ocean and ice-sheet formation. The formation of valley networks early in Mars' history is evidence for a long-term hydrological cycle, which may have been associated with the existence of a persistent ocean. Cataclysmic flooding, triggered by extensive Tharsis volcanism, subsequently led to repeated ocean formation and then dissipation on the northern plains, and associated glaciation in the southern highlands until relatively late in martian history.
C1 UNIV ARIZONA,DEPT GEOSCI,TUCSON,AZ 85721.
   UNIV POONA,DEPT GEOG,POONA 411007,MAHARASHTRA,INDIA.
C3 University of Arizona; Savitribai Phule Pune University
RP BAKER, VR (corresponding author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA.
NR 53
TC 593
Z9 655
U1 0
U2 115
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 589
EP 594
DI 10.1038/352589a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100045
DA 2026-03-10
ER

PT J
AU WANEK, N
   GARDINER, DM
   MUNEOKA, K
   BRYANT, SV
AF WANEK, N
   GARDINER, DM
   MUNEOKA, K
   BRYANT, SV
TI CONVERSION BY RETINOIC ACID OF ANTERIOR CELLS INTO ZPA CELLS IN THE CHICK WING BUD
SO NATURE
LA English
DT Article
ID polarizing region; pattern-formation; limb bud; digits
AB IN recent years there has been considerable interest in the role of retinoic acid (RA) in vertebrate-limb pattern formation. When RA is applied to the anterior of the chick wing bud, a mirror-image duplication of the limb pattern develops that is identical to the pattern resulting from grafts of posterior tissue (zone of polarizing activity, or ZPA) 1. It has been proposed that position along the anterior-posterior axis in the chick limb is specified by a gradient of a diffusible factor produced by the ZPA 2. The ZPA-mimicking action of RA has led to the hypothesis that exogenously applied RA acts by providing graded spatial information across the anterior-posterior limb axis 3,4. An alternative interpretation is that RA changes anterior cells into ZPA cells, which in turn provide the actual pattern-duplicating stimulus 3-5; there is already some preliminary evidence that this occurs 5. A hybrid interpretation has also been suggested whereby ZPA cells are formed in response to RA exposure and then begin to release retinoids that act as graded spatial cues 3. We have used a functional assay 6 to test anterior chick wing-bud cells for ZPA activity after exposure to RA. The results of our studies indicate that the action of RA is to change anterior cells into ZPA cells. Further, our results indicate that it is unlikely that RA-treated anterior cells then begin producing RA in such a way as to provide a graded positional signal.
C1 UNIV CALIF IRVINE, CTR DEV BIOL, IRVINE, CA 92717 USA.
C3 University of California System; University of California Irvine
NR 19
TC 220
Z9 236
U1 0
U2 5
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 81
EP 83
DI 10.1038/350081a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300071
PM 2002849
DA 2026-03-10
ER

PT J
AU DRYER, SE
   HENDERSON, D
AF DRYER, SE
   HENDERSON, D
TI A CYCLIC GMP-ACTIVATED CHANNEL IN DISSOCIATED CELLS OF THE CHICK PINEAL-GLAND
SO NATURE
LA English
DT Article
ID single ion channels; rod inner segments; photoendocrine transduction; concentration-dependence; melatonin rhythm; light
AB PHOTOTRANSDUCTION in the vertebrate retina is dependent in part on a cyclic GMP-activated ionic channel in the plasma membrane of rods and cones 1,2. But other vertebrate cells are also photosensitive. Cells of the chick pineal gland have a photosensitive circadian rhythm in melatonin secretion that persists in dissociated cell culture 3,4. Exposure to light causes inhibition of melatonin secretion, and entrainment of the intrinsic circadian oscillator 5,6. Chick pinealocytes express several 'retinal' proteins, including arrestin 7, transducin 8 and a protein similar to the visual pigment rhodopsin 9. Pinealocytes of lower vertebrates display hyperpolarizing responses to brief pulses of light 10,11. Thus it is possible that some of the mechanisms of phototransduction are similar in retinal and pineal photoreceptors. We report here the first recordings of cyclic GMP-activated channels in an extraretinal photoreceptor. Application of GMP, but not cyclic AMP, to excised inside-out patches caused activation of a 15-25 pS cationic channel. These channels may be essential for phototransduction in the chick pineal gland.
RP DRYER, SE (corresponding author), FLORIDA STATE UNIV, DEPT BIOL SCI B157, PROGRAM PSYCHOBIOL & NEUROSCI, TALLAHASSEE, FL 32306 USA.
NR 19
TC 100
Z9 102
U1 0
U2 3
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 756
EP 758
DI 10.1038/353756a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600069
PM 1719422
DA 2026-03-10
ER

PT J
AU SPRINGER, TA
AF SPRINGER, TA
TI THE NEXT CLUSTER OF DIFFERENTIATION (CD) WORKSHOP
SO NATURE
LA English
DT Article
RP SPRINGER, TA (corresponding author), HARVARD UNIV,SCH MED,CTR BLOOD RES,800 HUNTINGTON AVE,BOSTON,MA 02115, USA.
NR 6
TC 0
Z9 1
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 415
EP 416
DI 10.1038/354415a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100058
PM 1956408
DA 2026-03-10
ER

PT J
AU JANSEN, E
   SJOHOLM, J
AF JANSEN, E
   SJOHOLM, J
TI RECONSTRUCTION OF GLACIATION OVER THE PAST 6 MYR FROM ICE-BORNE DEPOSITS IN THE NORWEGIAN SEA
SO NATURE
LA English
DT Article
ID quartz sand grains; isotope record; history; environments; textures; iceland; volume; ocean
AB IT is well known that a significant intensification of Northern Hemisphere glaciation occurred approximately 2.5 Myr ago, in contrast to the much earlier onset (approximately 35 Myr) of glaciation in Antarctica 1-3.  Much less is known about the behaviour of the climate before 2.5 Myr, and it has remained unclear when sizeable glaciers first started to develop in the Northern Hemisphere.  Here we deduce the history of high-northern-latitude glaciation over the past 6 Myr from records of ice-borne deposits in deep-sea sediments of the Norwegian Sea.  We find that glaciers large enough to reach sea level were present in the Norwegian Sea area as early as 5.5 Myr, three million years before the intensification of glaciation at 2.5 Myr.  Fluctuations in ice volume can be deduced from the oxygen isotope record, but this provides only a global average, which may not reflect the history of ice-sheet growth in specific regions.  From a comparison of the oxygen isotope records with the record of ice-rafted material, we derive an estimate of the relative contributions of Southern and Northern Hemisphere glaciation to global variations in ice volume.
RP JANSEN, E (corresponding author), UNIV BERGEN,DEPT GEOL,SECT B,ALLEGATEN 41,N-5007 BERGEN,NORWAY.
NR 35
TC 266
Z9 286
U1 0
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 600
EP 603
DI 10.1038/349600a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000056
DA 2026-03-10
ER

PT J
AU RITTER, AM
   LEWIN, GR
   KREMER, NE
   MENDELL, LM
AF RITTER, AM
   LEWIN, GR
   KREMER, NE
   MENDELL, LM
TI REQUIREMENT FOR NERVE GROWTH-FACTOR IN THE DEVELOPMENT OF MYELINATED NOCICEPTORS INVIVO
SO NATURE
LA English
DT Article
ID hairy skin; rat; mechanoreceptors; receptor; survival
AB IN adult animals, sensory neurons innervating the skin are phenotypically diverse 1-3.  We have now investigated whether nerve growth factor (NGF) has a physiological role in the development of this diversity.  We gave antisera against NGF to rats from postnatal day 1 (PND 1) to adulthood (5 weeks).  We found a virtually complete depletion of high threshold mechanoreceptors conducting in the A-delta range (2-13 m s-1) in the sural nerve.  This afferent type, normally present in large numbers, appeared to have been replaced by D-hair afferents, sensitive mechanoreceptors which normally are relatively rare.  NGF deprivation had this effect only in early postnatal life; treatment from postnatal day 14 to adulthood had no effect.  We conclude that the presence of NGF postnatally in skin is necessary for the proper phenotypic development of A-delta cutaneous nociceptors.
C1 SUNY STONY BROOK,DEPT NEUROBIOL & BEHAV,STONY BROOK,NY 11794.
C3 State University of New York (SUNY) System; Stony Brook University
NR 17
TC 143
Z9 159
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 500
EP 502
DI 10.1038/350500a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300051
PM 2014050
DA 2026-03-10
ER

PT J
AU LAMARRE, E
   MELVILLE, WK
AF LAMARRE, E
   MELVILLE, WK
TI AIR ENTRAINMENT AND DISSIPATION IN BREAKING WAVES
SO NATURE
LA English
DT Article
ID bubble; layer; sea
AB WAVE breaking transfers momentum from the atmosphere (winds) to the ocean (currents) 1,2 and entrains air in bubbles which are believed to generate and scatter underwater sound 3-5. Wave breaking and the associated entrainment of air in bubbles are also thought to be important in heat and gas transfer across the air-sea interface 6-8, but the lack of detailed measurements of air entrainment in bubbles has impeded our understanding of the effect of wave breaking on these processes. Here we present measurements of air entrainment by controlled deep-water breaking waves, which show that the bubble plumes generated by breaking waves contain volume fractions of air that are many orders of magnitude greater than expected. Bubble plumes with such large void fractions may be the source of low-frequency sound in the ocean 9. We conclude that the processes of surface-wave evolution and air entrainment are dynamically coupled, and that the contribution of bubbles to air-sea gas transfer and to sound propagation may be seriously underestimated if the existence of these plumes of large bubbles is not taken into account.
RP LAMARRE, E (corresponding author), MIT, DEPT CIVIL ENGN, RM PARSONS LAB, CAMBRIDGE, MA 02139 USA.
NR 17
TC 245
Z9 288
U1 0
U2 42
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 469
EP 472
DI 10.1038/351469a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800051
DA 2026-03-10
ER

PT J
AU SCHORLE, H
   HOLTSCHKE, T
   HUNIG, T
   SCHIMPL, A
   HORAK, I
AF SCHORLE, H
   HOLTSCHKE, T
   HUNIG, T
   SCHIMPL, A
   HORAK, I
TI DEVELOPMENT AND FUNCTION OF T-CELLS IN MICE RENDERED INTERLEUKIN-2 DEFICIENT BY GENE TARGETING
SO NATURE
LA English
DT Article
ID embryonic stem-cells; severe combined immunodeficiency; germ-line transmission; mouse interleukin-2; hprt gene; receptor; antibody; differentiation; culture
AB INTERLEUKIN-2 (IL-2) is a lymphocytotropic hormone which is thought to have a key role in the immune response of mammalian cells. It is produced by a subpopulation of activated T-lymphocytes and acts in vitro as the principal auto- and paracrine T-cell growth factor (for reviews see refs 1-3). IL-2 is, however, not the sole T-cell growth factor 4,5, nor does it act exclusively on T cells, also promoting growth of NK cells 6 and differentiation of B cells 7. A role for IL-2 in T-cell development has been postulated but remains controversial 8-12. Here we test the requirement for IL using IL-2-deficient mice generated by targeted recombination. We find that mice homozygous for the IL-2 gene mutation are normal with regard to thymocyte and peripheral T-cell subset composition, but that a dysregulation of the immune system is manifested by reduced polyclonal in vitro T-cell responses and by dramatic changes in the isotype levels of serum immunoglobulins.
C1 UNIV WURZBURG, INST VIROL & IMMUNOBIOL, VERSBACHERSTR 7, W-8700 WURZBURG, GERMANY.
C3 University of Wurzburg
NR 29
TC 793
Z9 851
U1 0
U2 13
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 621
EP 624
DI 10.1038/352621a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100056
PM 1830926
DA 2026-03-10
ER

PT J
AU WU, J
   MANLEY, JL
AF WU, J
   MANLEY, JL
TI BASE-PAIRING BETWEEN U2 AND U6 SNRNAS IS NECESSARY FOR SPLICING OF A MAMMALIAN PRE-MESSENGER-RNA
SO NATURE
LA English
DT Article
ID small nuclear ribonucleoprotein; branch site selection; genes even though; u1 snrna; efficient transcription; different polymerase; 2'-ome rna; yeast; particles; elements
AB SPLICING of pre-messenger RNA in eukaryotic cells occurs in a multicomponent complex termed the spliceosome, which contains small nuclear ribonucleoprotein particles (snRNPs), protein factors and substrate pre-mRNA 1-3.  Assembly of the spliceosome involves the stepwise binding of snRNPs and protein factors to the pre-mRNA through a poorly understood mechanism which probably involves specific RNA-RNA, RNA-protein and protein-protein interactions.  Of particular interest are the interactions between snRNPs, which are likely to be important not only for assembly of the spliceosome but also for catalysis.  U1 snRNP interacts with the 5' splice site and U2 snRNP with the branch site of the pre-mRNA; both of these interactions involve Watson-Crick base pairing 4-9.  But very little is known about how other factors such as the U4/U6 and U5 snRNPs reach the spliceosome and function in splicing.  Here we report evidence that U6 snRNA interacts directly with U2 snRNA by a mechanism involving base-pairing, and that this interaction can be necessary for splicing of a mammalian pre-mRNA in vivo.
RP WU, J (corresponding author), COLUMBIA UNIV,DEPT BIOL SCI,NEW YORK,NY 10027, USA.
NR 32
TC 162
Z9 177
U1 1
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 818
EP 821
DI 10.1038/352818a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400065
PM 1831878
DA 2026-03-10
ER

PT J
AU ODELL, TJ
   KANDEL, ER
   GRANT, SGN
AF ODELL, TJ
   KANDEL, ER
   GRANT, SGN
TI LONG-TERM POTENTIATION IN THE HIPPOCAMPUS IS BLOCKED BY TYROSINE KINASE INHIBITORS
SO NATURE
LA English
DT Article
ID dependent protein-kinase; epidermal growth-factor; src gene-product; rat-brain; phorbol esters; phosphorylation; receptor; slices; cells
AB LONG-TERM potentiation (LTP) in the hippocampus is thought to contribute to memory formation.  In the Ca1 region, LTP requires the NMDA (N-methyl-D-aspartate) receptor-dependent influx of Ca2+ and activation of serine and threonine protein kinases.  Because of the high amount of protein tyrosine kinases in hippocampus and cerebellum 1,2, two regions implicated in learning and memory, we examined the possible additional requirement of tyrosine kinase activity in LTP.  We first examined the specificity in brain of five inhibitors of tyrosine kinase 3-5 (Table 1) and found that two of them, lavendustin A and genistein, showed substantially greater specificity for tyrosine kinase from hippocampus 6 than for three serine-threonine kinases:  protein kinase A, protein kinase C, and Ca2+/calmodulin kinase II.  Lavendustin A and genistein selectively blocked the induction of LTP when applied in the bath or injected into the postsynaptic cell.  By contrast, the inhibitors had no effect on the established LTP, on normal synaptic transmission, or on the neurotransmitter actions attributable to the actions of protein kinase A or protein kinase C.  These data suggest that tyrosine kinase activity could be required postsynaptically for long-term synaptic plasticity in the hippocampus.  As Ca2+ calmodulin kinase II or protein kinase C seem also to be required 7,8, the tyrosine kinases could participate postsynaptically in a kinase network together with serine and threonine kinases.
C1 COLUMBIA UNIV COLL PHYS & SURG,HOWARD HUGHES MED INST,NEW YORK,NY 10032.
C3 Columbia University; Howard Hughes Medical Institute
RP ODELL, TJ (corresponding author), COLUMBIA UNIV COLL PHYS & SURG,CTR NEUROBIOL & BEHAV,722 W 168TH ST,NEW YORK,NY 10032, USA.
NR 29
TC 514
Z9 553
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 558
EP 560
DI 10.1038/353558a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300067
PM 1656271
DA 2026-03-10
ER

PT J
AU CLAGUE, DA
   WEBER, WS
   DIXON, JE
AF CLAGUE, DA
   WEBER, WS
   DIXON, JE
TI PICRITIC GLASSES FROM HAWAII
SO NATURE
LA English
DT Article
ID silicate liquids; major-element; kilauea; origin; melts
AB ESTIMATES of the MgO content of primary Hawaiian tholeiitic melts range from 8 wt% to as high as 25 wt% (refs 1, 2).  In general, these estimates are derived from analysis of the whole-rock composition of lavas, coupled with the compositions of the most magnesian olivine phenocrysts observed.  But the best estimate of magma composition comes from volcanic glass, as it represents the liquid composition at the time of quenching; minimal changes occur during the quenching process.  Here we report the discovery of tholeiitic basalt glasses, recovered offshore of Kilauea volcano, that contain up to 15.0 wt% MgO.   To our knowledge, these are the most magnesian glasses, and have the highest eruption temperatures (approximately 1,316-degrees-C), yet found.   The existence of these picritic (high-MgO) liquids provides constraints on the temperature structure of the upper mantle, magma transport and the material and thermal budgets of the Hawaiian volcanoes.  Furthermore, picritic melts are affected little by magma-reservoir processes, and it is therefore relatively straightforward to extrapolate back to the composition of the primary melt and its volatile contents.
C1 CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125.
C3 California Institute of Technology
RP CLAGUE, DA (corresponding author), US GEOL SURVEY,MENLO PK,CA 94025, USA.
NR 19
TC 120
Z9 126
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 553
EP 556
DI 10.1038/353553a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300065
DA 2026-03-10
ER

PT J
AU STEPHENS, LR
   HUGHES, KT
   IRVINE, RF
AF STEPHENS, LR
   HUGHES, KT
   IRVINE, RF
TI PATHWAY OF PHOSPHATIDYLINOSITOL(3,4,5)-TRISPHOSPHATE SYNTHESIS IN ACTIVATED NEUTROPHILS
SO NATURE
LA English
DT Article
ID phosphatidylinositol kinase-activity; inositol phosphates; bovine brain; 4,5-bisphosphate; identification; 4-phosphate; polyphosphoinositide; phosphodiesterase; transformation; trisphosphate
AB Neutrophils activated by the formyl peptide f-Met-LeuPhe transiently accumulate a small subset of highly polar inositol lipids.  A similar family of lipids also appear in many other cells in response to a range of growth factors and activated oncogenes, and are presumed to be the direct or indirect products of 3-phosphatidylinositol kinase.  The structures of these lipids are shown to be phosphatidylinositol 3-phosphate, phosphatidylinositol-(3,4)bisphosphate and phosphatidylinositol-(3,4,5)trisphosphate, and we present evidence that in intact neutrophils a phosphatidyl-inositol-(4,5)bisphosphate-3-kinase seems to be the focal point through which agonists stimulate the formation of 3-phosphorylated inositol lipids.
C1 AMERSHAM INT PLC,CARDIFF CF4 7YT,WALES.
RP STEPHENS, LR (corresponding author), AFRC,INST ANIM PHYSIOL & GENET RES,CAMBRIDGE RES STN,DEPT BIOCHEM,CAMBRIDGE CB2 4AT,ENGLAND.
NR 50
TC 455
Z9 522
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 33
EP 39
DI 10.1038/351033a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300049
PM 1851250
DA 2026-03-10
ER

PT J
AU KERR, RC
AF KERR, RC
TI EROSION OF A STABLE DENSITY GRADIENT BY SEDIMENTATION-DRIVEN CONVECTION
SO NATURE
LA English
DT Article
ID turbidity currents; sea
AB STABLE density gradients are common in the world's oceans and lakes, and play a crucial part in their physical, chemical and biological evolution.  It has recently been suggested 1 that turbidity currents provide an indirect mechanism for eroding this stratification.  In these currents, light ambient fluid that has been mixed by cyclones with dense suspended sediment is transported to greater depths, where it convectively erodes the gradient as the sediment settles.  Here I present experimental results which show that in these circumstances the density gradient is eroded in a number of cycles of decreasing intensity and increasing duration.  In each cycle some of the sediment settles to the base of a stagnant region of unimpeded sedimentation, while the rest is mixed into an overlying region that is vigorously convecting.  My experimental observations agree with a simple physical model that predicts the rate and extent of vertical mixing as well as the variation of particle sizes in the resulting turbidite.
RP KERR, RC (corresponding author), AUSTRALIAN NATL UNIV,RES SCH EARTH SCI,GPO BOX 4,CANBERRA,ACT 2601,AUSTRALIA.
NR 20
TC 29
Z9 29
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 423
EP 425
DI 10.1038/353423a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600054
DA 2026-03-10
ER

PT J
AU DIRICK, L
   NASMYTH, K
AF DIRICK, L
   NASMYTH, K
TI POSITIVE FEEDBACK IN THE ACTIVATION OF G1 CYCLINS IN YEAST
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; ho gene; mating-pheromone; cell; arrest; size
AB YEAST cells become committed to the mitotic cell cycle at a stage during G1 called Start 1.  To enter Start, cells must grow to a critical size. They also require the CDC28 protein kinase and at least one of three G1-specific cyclins encoded by CLN1, 2, and 3 (refs 2-4). It is thought that Start is triggered by the accumulation of G1 cyclins that bind to the CDC28 kinase and activate it. So what determines the accumulation of G1 cyclins? For CLN1 and CLN2, transcriptional activation could be involved because their RNAs appear transiently during the cell cycle as cells undergo Start 5.  Here we report that the appearance of CLN1 and CLN2 RNAs depends on an active CDC28 kinase and is stimulated by CLN3 activity. We propose that CDC28 kinase activity due to CLN1 and CLN2 proteins arises through a positive feedback loop which allows CLN proteins to promote their own synthesis.
RP DIRICK, L (corresponding author), RES INST MOLEC PATHOL,DR BOHR GASSE 7,A-1030 VIENNA,AUSTRIA.
NR 19
TC 174
Z9 197
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 754
EP 757
DI 10.1038/351754a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100067
PM 1829507
DA 2026-03-10
ER

PT J
AU PAOLINI, R
   JOUVIN, MH
   KINET, JP
AF PAOLINI, R
   JOUVIN, MH
   KINET, JP
TI PHOSPHORYLATION AND DEPHOSPHORYLATION OF THE HIGH-AFFINITY RECEPTOR FOR IMMUNOGLOBULIN-E IMMEDIATELY AFTER RECEPTOR ENGAGEMENT AND DISENGAGEMENT
SO NATURE
LA English
DT Article
ID cell antigen receptor; natural-killer-cells; fc-gamma receptor; ige receptor; zeta-chain; molecular-cloning; cd16; expression; subunit; riii
AB TRIGGERING of mast cells and basophils by immunoglobulin E (IgE) and antigen induces various biochemical signals, including tyrosine kinase activation 1,2, which lead to cell degranulation and the release of mediators of the allergic reaction. The high-affinity receptor for IgE (Fc-epsilon-RI) responsible for initiating these events is a complex structure composed of an IgE-binding alpha-chain, a beta-chain and a homodimer of gamma-chains 3.  It has been assumed that beta and gamma, which have extensive cytoplasmic domains, play an important but undefined role in coupling Fc-epsilon-RI to signal transduction mechanisms. Here we show that Fc-epsilon-RI engagement induces immediate in vivo phosphorylation on beta (tyrosine and serine) and gamma (tyrosine and threonine) by at least two different non-receptor kinases. We take advantage of unique features of this receptor system to demonstrate that the phosphorylation signal is restricted to activated receptors and is immediately reversible upon receptor disengagement by undefined phosphatases. Rapid phosphorylation and dephosphorylation may be a general mechanism to couple and uncouple activated receptors to other effector molecules. This could be particularly relevant to other multimeric receptors containing Fc-epsilon-RI gamma-chains or the related-zeta and eta-chains such as the T-cell antigen receptor (TCR) 4-6 and the low-affinity receptor for immunoglobulin G (Fc-gamma-RIII, CD16) (refs 7-11).
RP PAOLINI, R (corresponding author), NIAID,MOLEC ALLERGY & IMMUNOL SECT,TWINBROOK II BLDG,12441 PARKLAWN DR,ROCKVILLE,MD 20852, USA.
NR 28
TC 286
Z9 301
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 855
EP 858
DI 10.1038/353855a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200063
PM 1834946
DA 2026-03-10
ER

PT J
AU WANG, WC
   DUDEK, MP
   LIANG, XZ
   KIEHL, JT
AF WANG, WC
   DUDEK, MP
   LIANG, XZ
   KIEHL, JT
TI INADEQUACY OF EFFECTIVE CO2 AS A PROXY IN SIMULATING THE GREENHOUSE-EFFECT OF OTHER RADIATIVELY ACTIVE GASES
SO NATURE
LA English
DT Article
ID climate-chemical interactions; atmospheric trace gases; global climate; feedback; chlorofluorocarbons; perturbations
AB The use of an 'effective' CO2 concentration to simulate the combined greenhouse effect of CO2 and the trace gases CH4, N2O, CFC-11 and CFC-12 is open to question, because the radiative-forcing behaviour of CO2 is very different from that of these other gases.  Model simulations show that different radiative forcing can lead to quite different climatic effects.  The thermal infrared opacity of these trace gases therefore needs to be explicitly accounted for when attempting to predict the climate response to increasing concentrations of greenhouse gases.
C1 NATL CTR ATMOSPHER RES,BOULDER,CO 80307.
C3 National Center Atmospheric Research (NCAR) - USA
RP WANG, WC (corresponding author), SUNY ALBANY,ATMOSPHER SCI RES CTR,ALBANY,NY 12005, USA.
NR 26
TC 86
Z9 86
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 573
EP 577
DI 10.1038/350573a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200048
DA 2026-03-10
ER

PT J
AU LLOYD, A
   YANCHEVA, N
   WASYLYK, B
AF LLOYD, A
   YANCHEVA, N
   WASYLYK, B
TI TRANSFORMATION SUPPRESSOR ACTIVITY OF A JUN TRANSCRIPTION FACTOR LACKING ITS ACTIVATION DOMAIN
SO NATURE
LA English
DT Article
ID c-jun; gene; expression; cells
AB THE oncoprotein c-Jun is thought to be a mediator of ras transformation as both its synthesis and activity as a transcription factor are stimulated by ras expression 1,2. But c-Jun co-operates with ras in transformation assays 3, suggesting that they act along different pathways (reviewed in ref. 4). Here we show by means of a dominant-negative mutated transcription factor that c-Jun potentially in conjunction with other factors that interact with it is necessary for transformation by ras. The mutant Jun lacks an activation domain and blocks stimulation of transcription by several oncoproteins, including Ras, v-Src, polyoma middle T, c-Jun and c-Fos, as well as by the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). The inhibition is specific for motifs that bind Jun:  activation of an NF-kappa B/Rel motif is not affected. This Jun mutant acts as an anti-oncogene in ras-transformed cells, generating non-transformed revertants that have acquired anchorage and density-dependent growth, as well as reduced tumorigenicity in vivo. Mutants of other transcription factors designed to inhibit transformation will enable us to study their role in signal transduction.
C1 FAC MED STRASBOURG,INST CHIM BIOL,CNRS,GENET MOLEC EUCARYOTES LAB,INSERM,U184,11 RUE HUMANN,F-67085 STRASBOURG,FRANCE.
C3 Institut National de la Sante et de la Recherche Medicale (Inserm); Centre National de la Recherche Scientifique (CNRS); Universites de Strasbourg Etablissements Associes; Universite de Strasbourg
NR 17
TC 186
Z9 195
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 632
EP 638
DI 10.1038/352635a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100060
PM 1907719
DA 2026-03-10
ER

PT J
AU ELDRIDGE, CS
   COMPSTON, W
   WILLIAMS, IS
   HARRIS, JW
   BRISTOW, JW
AF ELDRIDGE, CS
   COMPSTON, W
   WILLIAMS, IS
   HARRIS, JW
   BRISTOW, JW
TI ISOTOPE EVIDENCE FOR THE INVOLVEMENT OF RECYCLED SEDIMENTS IN DIAMOND FORMATION
SO NATURE
LA English
DT Article
ID eclogitic diamonds; sulfide inclusions; mantle; carbon; xenoliths; sulfur; kimberlite; nitrogen; africa; ratios
AB DIAMONDS, as chemically robust containers of material from the mantle, have provided important information regarding the evolution of the Earth's interior 1; yet despite much effort 2-9, the origins of diamonds themselves have remained controversial 10-13. Sulphur isotope ratios measured in most mantle or meteoritic samples exhibit minimal deviation from the meteoritic standard, whereas the ratios in crustal materials deviate by as much as +/- 70 parts per thousand (ref. 14): for this reason, isotopic studies of sulphide mineral inclusions in diamonds and mantle material are an attractive means of investigating the possible role of crust-mantle interaction in the formation of diamonds 15. Recent ion microprobe studies have found departures from mantle values in the sulphur isotope compositions of individual diamond inclusions 16 and some mantle rocks 17, which would be consistent with subduction of altered ocean crust into the region of diamond growth. Here we present new sulphur and lead isotope data from diamond sulphide inclusions, which suggest that sedimentary material might also be subducted into the mantle and that the crustal recycling process has been operative for at least 1,000 million years.
C1 AUSTRALIAN NATL UNIV,RES SCH EARTH SCI,CANBERRA,ACT 2601,AUSTRALIA.
   UNIV GLASGOW,DEPT GEOL & APPL GEOL,GLASGOW G12 8QQ,SCOTLAND.
   ANGLO AMER CORP LTD,RES LAB,CROWN MINES 2025,SOUTH AFRICA.
C3 Australian National University; University of Glasgow
RP ELDRIDGE, CS (corresponding author), AUSTRALIAN NATL UNIV,DEPT GEOL,GPO BOX 4,CANBERRA,ACT 2601,AUSTRALIA.
NR 28
TC 143
Z9 164
U1 0
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 649
EP 653
DI 10.1038/353649a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200066
DA 2026-03-10
ER

PT J
AU MOZZARELLI, A
   RIVETTI, C
   ROSSI, GL
   HENRY, ER
   EATON, WA
AF MOZZARELLI, A
   RIVETTI, C
   ROSSI, GL
   HENRY, ER
   EATON, WA
TI CRYSTALS OF HEMOGLOBIN WITH THE T-QUARTERNARY STRUCTURE BIND OXYGEN NONCOOPERATIVELY WITH NO BOHR EFFECT
SO NATURE
LA English
DT Article
ID human-hemoglobin; single-crystals; stereochemistry; mechanisms; constants; affinity; enzyme; state
AB THE relationship between the structure and function of haemoglobin has mainly been studied by comparing its X-ray crystal structures with its function in solutions 1-11.  To make a direct comparison we have studied the functional properties of haemoglobin in single crystals, an approach that has been an important part of the investigation of several enzyme mechanisms 12, 13.  Here we report on the oxygen binding by single crystals of human haemoglobin grown in solutions of polyethylene glycol.  Unlike haemoglobin crystals formed in concentrated salt solution, which crack and become disordered on oxygenation 14-16, crystals grown in polyethylene glycol remain intact.  X-ray studies have shown that the T (deoxy) quaternary structure of haemoglobin in this crystal at pH 7.0 is maintained at atmospheric oxygen pressure, and that the salt-bridges are not broken 17-19.  We find striking differences between oxygen binding by haemoglobin in this crystal and by haemoglobin in solution.  Not only is oxygenation of the crystal noncooperative, but the oxygen affinity is independent of pH in the range 6.0-8.5, and is much lower than that of the T state in solution.  The lack of cooperativity without a change in quaternary structure is predicted by the two-state allosteric model of Monod, Wyman and Changeux 1, 5.  The absence of a Bohr effect without breakage of salt-bridges is predicted by Perutz's stereochemical mechanism 2, 4, 9-11.  In contrast to the X-ray result that oxygen binds only to the alpha-haems, our measurements show that the alpha-haems have only a slightly higher affinity than the beta-haems.
C1 NIDDKD,CHEM PHYS LAB,BETHESDA,MD 20892.
C3 National Institutes of Health (NIH) - USA; NIH National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK)
RP MOZZARELLI, A (corresponding author), UNIV PARMA,INST BIOCHEM SCI,I-43100 PARMA,ITALY.
NR 35
TC 122
Z9 122
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 416
EP 419
DI 10.1038/351416a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600062
PM 2034292
DA 2026-03-10
ER

PT J
AU BERGE, B
   FAUCHEUX, L
   SCHWAB, K
   LIBCHABER, A
AF BERGE, B
   FAUCHEUX, L
   SCHWAB, K
   LIBCHABER, A
TI FACETED CRYSTAL-GROWTH IN 2 DIMENSIONS
SO NATURE
LA English
DT Article
ID sodium dodecyl-sulfate; phase-diagram; models
AB CRYSTAL growth has attracted interest for centuries 1. Three-dimensional crystals are usually faceted, but equilibrium thermodynamics prohibits faceting in two dimensions 2:  the one-dimensional perimeter of a two-dimensional crystal cannot exhibit long-range order at any non-zero temperature 3.  This need not, however, prevent facets from being stable dynamically during the growth process. Computer simulations have indeed produced nearly faceted two-dimensional crystals 4,5.  Here we describe the results of experiments on monolayers of a surfactant, sodium dodecyl sulphate (SDS), at the surface of an aqueous solution.  Surface-tension measurements and fluorescence microscopy 6-8 reveal a solid-liquid transition in the surface monolayer at fixed SDS bulk concentration, as the temperature is decreased.  At low SDS concentration, faceted monolayer crystals appear, although increasing the concentration induces a change to smoother growth morphologies.  The faceted crystals become unstable as growth proceeds, the corners emitting filaments of various shapes.  Some of these growth processes seem not to have three-dimensional analogues.
C1 ENRICO FERMI INST,CHICAGO,IL 60637.
   LAB SPECTROMETRIE PHYS,F-38402 ST MARTIN DHERES,FRANCE.
RP BERGE, B (corresponding author), JAMES FRANCK INST,5640 S ELLIS AVE,CHICAGO,IL 60637, USA.
NR 23
TC 81
Z9 84
U1 0
U2 38
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 322
EP 324
DI 10.1038/350322a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800085
DA 2026-03-10
ER

PT J
AU TILMAN, D
   WEDIN, D
AF TILMAN, D
   WEDIN, D
TI OSCILLATIONS AND CHAOS IN THE DYNAMICS OF A PERENNIAL GRASS
SO NATURE
LA English
DT Article
ID herbaceous vegetation; time-series; litter; populations; error
AB ECOLOGICAL models describe the conditions required for chaotic population dynamics 1-7, but there are few studies with which to test these predictions 4,8-10, and none for perennial plants. In a five-year experiment, a perennial grass exhibited numerous traits associated with chaotic dynamics. Biomass oscillations were greater on more productive soils, with plots on the richest soils exhibiting a 6,000-fold crash. Curves relating the biomass one year to that in the previous year had the peaks and steep slopes associated with chaos, and the dependence of plant biomass on productivity became fuzzy over time. These dynamics resulted from the time-delayed inhibitory effect of plant litter on subsequent growth. A model incorporating litter inhibition predicts oscillations and chaos as productivity increases.
RP TILMAN, D (corresponding author), UNIV MINNESOTA,DEPT ECOL EVOLUT & BEHAV,MINNEAPOLIS,MN 55455, USA.
NR 19
TC 150
Z9 171
U1 0
U2 34
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 653
EP 655
DI 10.1038/353653a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200067
DA 2026-03-10
ER

PT J
AU BARSTOW, MA
   BROMAGE, GE
   PANKIEWICZ, GS
   GONZALEZRIESTRA, R
   DENBY, M
   PYE, JP
AF BARSTOW, MA
   BROMAGE, GE
   PANKIEWICZ, GS
   GONZALEZRIESTRA, R
   DENBY, M
   PYE, JP
TI DETECTION OF A STELLAR FLARE AT EXTREME ULTRAVIOLET WAVELENGTHS
SO NATURE
LA English
DT Article
ID interstellar
AB THE transition region between stellar chromospheres and coronae contains plasma at temperatures of 10(5)-10(6) K, radiating predominantly at extreme ultraviolet (EUV) wavelengths (60-1,000 angstrom; 0.012-0.2 keV). To understand the energy transport processes that maintain the corona, radiative losses from this region must be studied, particularly during the dramatic energy release that occurs in a stellar flare. During the all-sky survey conducted by the Rosat Wide Field Camera 1, we monitored the binary flare star system BY Draconis, with coverage by the International Ultraviolet Explorer satellite far ultraviolet and optical observations and by the Rosat X-ray telescope 2 for part of the time. We detected a stellar flare in all four wavebands. This is the first unambiguous extreme ultraviolet detection of a flare, and one of the widest simultaneous wavelength-range coverages obtained. The peak luminosity and total energy of this flare, in the photon energy range 0.08-0.18 keV, are comparable with the values obtained for a number of flares integrated over a larger energy range (0.05-2.0 keV) by Exosat satellite observations in 1983-86. We conclude that radiation in the extreme ultraviolet carries away a substantial fraction of the total flare energy.
C1 RUTHERFORD APPLETON LAB,SPACE ASTRON GRP,DIDCOT OX11 0QX,OXON,ENGLAND.
   IUE OBSERV,MADRID,SPAIN.
C3 UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory
RP BARSTOW, MA (corresponding author), UNIV LEICESTER,DEPT PHYS & ASTRON,LEICESTER LE1 7RH,ENGLAND.
NR 12
TC 4
Z9 4
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 635
EP 637
DI 10.1038/353635a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200060
DA 2026-03-10
ER

PT J
AU WEBSTER, A
AF WEBSTER, A
TI COMPARISON OF A CALCULATED SPECTRUM OF C60H60 WITH THE UNIDENTIFIED ASTRONOMICAL INFRARED-EMISSION FEATURES
SO NATURE
LA English
DT Article
ID ngc-7027; carbon; bands; c-60
AB INFRARED emission features consisting of narrow lines and broad plateaux, ranging from 3-mu-m in wavelength to over l2-mu-m, are seen in a wide variety of astronomical objects in which interstellar or circumstellar gas is illuminated by ultraviolet radiation from a star. Several candidates have been proposed as the source of this emission, but none is widely accepted. Here I calculate the vibrational spectrum of the fullerane C60H60, the saturated hydride of the soccerball-shaped molecule C60, using a force-field model. Six of the infrared active frequencies match unidentified emission lines to within 4%, and a seventh differs from an observed line by 8%. The calculation suggests why the astronomical feature at 7.7-mu-m is the strongest, and the observed variation of the 3.4-mu-m and 3.28-mu-m features with astrophysical environment is consistent with the idea that the former is attributable to stretching of the C-H bond in heavily hydrogenated fulleranes, whereas the latter is due to the same transition in lightly hydrogenated fulleranes.
RP WEBSTER, A (corresponding author), ROYAL OBSERV,BLACKFORD HILL,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND.
NR 18
TC 71
Z9 71
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 412
EP 414
DI 10.1038/352412a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600057
DA 2026-03-10
ER

PT J
AU CHIANG, HL
   SCHEKMAN, R
AF CHIANG, HL
   SCHEKMAN, R
TI REGULATED IMPORT AND DEGRADATION OF A CYTOSOLIC PROTEIN IN THE YEAST VACUOLE
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; secretory pathway; catabolite inactivation; structural gene; fructose-1,6-bisphosphatase; translocation; phosphorylation; proteolysis; encodes; glucose
AB The key regulatory enzyme in gluconeogenesis, fructose 1,6-bisphosphatase (FBPase) is subject to glucose-stimulated proteolytic degradation in Saccharomyces cerevisiae. This process involves the regulated transfer of FBPase directly from the cytosol into the vacuole or a vacuole-related organelle. Glucose may regulate the production of an FBPase receptor or import factor that is transported to the vacuole through the secretory pathway.
RP CHIANG, HL (corresponding author), UNIV CALIF BERKELEY, HOWARD HUGHES MED INST, DIV BIOCHEM & MOLEC BIOL, 401 BARKER HALL, BERKELEY, CA 94720 USA.
NR 32
TC 141
Z9 147
U1 0
U2 3
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 313
EP 318
DI 10.1038/350313a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800082
PM 1848921
DA 2026-03-10
ER

PT J
AU SATHYENDRANATH, S
   GOUVEIA, AD
   SHETYE, SR
   RAVINDRAN, P
   PLATT, T
AF SATHYENDRANATH, S
   GOUVEIA, AD
   SHETYE, SR
   RAVINDRAN, P
   PLATT, T
TI BIOLOGICAL-CONTROL OF SURFACE-TEMPERATURE IN THE ARABIAN SEA
SO NATURE
LA English
DT Article
ID southwest monsoon; mixed layer; ocean; phytoplankton; oceanography; color; model; onset
AB BY far the dominant variable parameter controlling the absorption cross-section for short-wavelength solar radiation incident on the ocean surface is the concentration of photosynthetic pigment contained in phytoplankton cells 1,2.  The abundance of phytoplankton depends on the intensity of incident radiation and on the supply of essential nutrients (nitrogen in particular).  A higher abundance increases absorption of radiation and thus enhances the rate of heating at the ocean surface. In the Arabian Sea, the southwest monsoon promotes seasonal upwelling of deep water, which supplies nutrients to the surface layer 3,4 and leads to a marked increase in phytoplankton growth.  Using remotely sensed data on ocean colour, we show here that the resulting distribution of phytoplankton exerts a controlling influence on the seasonal evolution of sea surface temperature.  This results in a corresponding modification of ocean-atmosphere heat exchange on regional and seasonal scales.  Thus we show that this biological mechanism may provide an important regulating influence on ocean-atmosphere interactions.
C1 FISHERIES & OCEANS CANADA,BEDFORD INST OCEANOG,DIV BIOL OCEANOG,DARTMOUTH B2Y 4A2,NS,CANADA.
   NATL INST OCEANOG,DIV PHYS OCEANOG,PANAJI 403004,GOA,INDIA.
C3 Bedford Institute of Oceanography; Fisheries & Oceans Canada; Council of Scientific & Industrial Research (CSIR) - India; CSIR - National Institute of Oceanography (NIO)
RP SATHYENDRANATH, S (corresponding author), DALHOUSIE UNIV,DEPT OCEANOG,HALIFAX B3H 4J1,NS,CANADA.
NR 23
TC 205
Z9 242
U1 2
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 54
EP 56
DI 10.1038/349054a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100047
DA 2026-03-10
ER

PT J
AU VAN DE VELDE, H
   VONHOEGEN, I
   LUO, W
   PARNES, JR
   THIELEMANS, K
AF VAN DE VELDE, H
   VONHOEGEN, I
   LUO, W
   PARNES, JR
   THIELEMANS, K
TI THE B-CELL SURFACE PROTEIN CD72/LYB-2 IS THE LIGAND FOR CD5
SO NATURE
LA English
DT Article
ID t-cells; differentiation antigen; lymphocytes-t; receptors; activation; adhesion; antibody; system; identification; expression
AB THE glycoprotein CD5 is expressed on the surface membrane of all mature T cells 1 and a small proportion of B lymphocytes 1, 2. Its exact role in immune interactions is still unknown. Studies 3-10 indicate that CD5 functions both in mice and humans as a receptor, delivering co-stimulatory signals to T cells in a manner similar to CD2 (ref. 11) and CD28 (ref. 12). Anti-CD5 antibodies stimulate both T-cell proliferation mediated by CD3 in association with the T-cell receptor and secretion of interleukin-2 and expression of its receptor, as well as inducing an increase in intracellular Ca2+ concentration (refs 5-10). To identify the ligand for CD5 we purified the human CD5 protein, labelled it with biotin and used it as a probe. Here we report that CD5 specifically interacts with the cell-surface protein CD72 exclusive to B cells. This interaction is blocked by anti-CD72 antibodies, but not by any other anti-B-cell antibodies. Moreover, non-B cells (mouse L-cell fibroblasts and human Jurkat T cells) expressing a transfected human CD72 complementary DNA could bind to the CD5-biotin conjugate. The results demonstrate that the B-cell surface protein CD72 (Lyb-2 in mice) is the ligand for CD5.
C1 VRIJE UNIV BRUSSELS, SCH MED, DIV HAEMATOL IMMUNOL, B-1090 BRUSSELS, BELGIUM.
   STANFORD UNIV, MED CTR, DEPT IMMUNOL & RHEUMATOL, STANFORD, CA 94305 USA.
C3 Vrije Universiteit Brussel; Universite Libre de Bruxelles; Stanford University
NR 32
TC 315
Z9 334
U1 0
U2 12
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 662
EP 665
DI 
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200070
PM 1711157
DA 2026-03-10
ER

PT J
AU SAMPEDRO, J
   GUERRERO, I
AF SAMPEDRO, J
   GUERRERO, I
TI UNRESTRICTED EXPRESSION OF THE DROSOPHILA GENE PATCHED ALLOWS A NORMAL SEGMENT POLARITY
SO NATURE
LA English
DT Article
ID pattern-formation; body pattern; embryos; requirements; wingless; protein; cuticle; larval
AB IN the Drosophila embryo, mutations in the segment polarity gene patched (ptc) cause the replacement of the middle region of each segment by a mirror-image duplication of the remaining structures, including the parasegmental border 1-3. This gene, which encodes a transmembrane protein, is initially expressed in a generalized way at blastoderm, but later stops being transcribed in cells expressing the engrailed gene, and even later in cells in the middle of the parasegment 2-4. The genes engrailed (en) and wingless (wg) are also segment-polarity genes, and they are expressed in adjacent stripes flanking the parasegment borders in the embryo 5; in ptc mutants wg expression extends anteriorly and an ectopic stripe of en expression is induced 6,7. The suggestion has been made that ptc must be transcribed in a specific subset of cells to prevent en expression anterior to the wg-expressing stripe 4. Here we report that unrestricted expression of ptc from a heat-shock promoter has no adverse effect on development of Drosophila embryos. The heat-shock construct can also rescue ptc mutants, restoring wg expression to its normal narrow stripe. The ectopic en stripe fails to appear, but the normal one remains unaffected. The results imply that, despite its localized requirement, the restricted expression of ptc does not itself allocate positional information.
C1 UNIV AUTONOMA MADRID, CSIC, CTR BIOL MOLEC, E-28049 MADRID, SPAIN.
C3 Consejo Superior de Investigaciones Cientificas (CSIC); Autonomous University of Madrid
NR 19
TC 31
Z9 42
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 187
EP 190
DI 10.1038/353187a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100060
PM 1653907
DA 2026-03-10
ER

PT J
AU NASRIN, N
   BUGGS, C
   KONG, XF
   CARNAZZA, J
   GOEBL, M
   ALEXANDERBRIDGES, M
AF NASRIN, N
   BUGGS, C
   KONG, XF
   CARNAZZA, J
   GOEBL, M
   ALEXANDERBRIDGES, M
TI DNA-BINDING PROPERTIES OF THE PRODUCT OF THE TESTIS-DETERMINING GENE AND A RELATED PROTEIN
SO NATURE
LA English
DT Article
ID sex-determining region; motif; expression; homology; cloning; cells; sry
AB THE upstream region of the human glyceraldehyde-3-phosphate dehydrogenase gene contains an insulin-response element (IRE-A) responsible for insulin-dependent transcription of the gene (ref. 1). The open reading frame of a rat complementary DNA encoding a protein (IRE-ABP) that binds to this sequence contains an HMG box motif 2 that is 67% identical to the mouse candidate gene for the testis-determining factor SRY, and 98% identical to the mouse SRY-like gene, alpha-4(refs 3, 4). Here we report that IRE-ABP and SRY bind to IRE-A DNA with comparable specificity in a DNase-I footprinting assay. Two females with sex reversal were found to have a single amino-acid substitution in the HMG box domain of SRY at position 3 and 7, respectively 5,6. SRY derivatives containing corresponding mutations do not make contact with IRE-A DNA. These results are direct evidence that mouse SRY-like proteins are sequence-specific DNA-binding proteins and identify two amino acids critical to this interaction. Moreover, IRE-A is a candidate SRY-response element.
C1 HARVARD UNIV,MASSACHUSETTS GEN HOSP,SCH MED,HOWARD HUGHES MED INST,DIABET UNIT,50 BLOSSOM ST,BOSTON,MA 02114.
   HARVARD UNIV,MASSACHUSETTS GEN HOSP,SCH MED,MED SERV,BOSTON,MA 02114.
C3 Howard Hughes Medical Institute; Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Massachusetts General Hospital; Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Massachusetts General Hospital
NR 17
TC 172
Z9 177
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 317
EP 320
DI 10.1038/354317a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400051
PM 1956382
DA 2026-03-10
ER

PT J
AU BELVEDERE, G
   PROCTOR, MRE
   LANZAFAME, G
AF BELVEDERE, G
   PROCTOR, MRE
   LANZAFAME, G
TI THE LATITUDE BELTS OF SOLAR-ACTIVITY AS A CONSEQUENCE OF A BOUNDARY-LAYER DYNAMO
SO NATURE
LA English
DT Article
ID stellar convective dynamos; numerical simulations; radiative interior; zone; cycle; propagation; interface; equations; rotation; model
AB HELIOSEISMOLOGY has provided much insight into the Sun's activity, allowing measurements of the thickness of the solar convection zone and the internal solar rotation rate as a function of latitude and depth. Solar activity is generally thought to result from dynamo action within the Sun, but there has been some debate as to whether this action occurs in the whole convection zone, at the base of the convection zone, or in the boundary layer between the convection and radiative zones 1,2 (about 0.65 R. to 0.7 R.).  Here we point out that recent helioseismological data 3-7  seem consistent with the last location.  We present the results of calculations on a model in which dynamo action arises in a very thin (0.05 R.) spherical boundary layer, which are consistent with the observations.  In particular, this model provides an explanation of why there exists a latitudinal boundary on the solar surface, below which features such as sunspots migrate towards the equator whereas above it they migrate polewards.
C1 UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,CAMBRIDGE,ENGLAND.
C3 University of Cambridge
RP BELVEDERE, G (corresponding author), UNIV CATANIA,IST ASTRON,VIALE DORIA 6,I-95124 CATANIA,ITALY.
NR 20
TC 26
Z9 26
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 481
EP 483
DI 10.1038/350481a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300043
DA 2026-03-10
ER

PT J
AU LEMON, WC
AF LEMON, WC
TI FITNESS CONSEQUENCES OF FORAGING BEHAVIOR IN THE ZEBRA FINCH
SO NATURE
LA English
DT Article
ID rates; time
AB OPTIMAL foraging theory is based on the assumption that natural selection favours animals that forage most efficiently 1-3. But such selection does not act directly on foraging efficiency, but rather indirectly by favouring animals that survive and reproduce most successfully. Studies that use optimal foraging models often assume that maximization of some behavioural currency, such as the animal's net rate of energy gain, maximizes the animal's fitness 4, but rarely is an attempt made to test this assumption 5-8. Most studies of the effects of foraging behaviour on fitness fail to control for the amount of energy gained by the foraging animals 5-8, and lead to the obvious conclusion that animals that eat more reproduce more. Often the studies do not control for characters correlated with foraging behaviour 6 or compare traits assumed to be correlated with fitness 7,8. A better method would be to assign net rates of energy gain to randomly chosen individuals for their entire lifetimes in a controlled environment and measure fitness directly. Variation in the amount of energy consumed would be controlled by using individuals that employ a time-minimizing foraging strategy 9 and would alter the time taken to satisfy their daily energy requirements, while obtaining the same absolute amount of energy. I have now manipulated the net rate of energy gain in four populations of the zebra finch Taeniopygia guttata, and show that fitness, as measured by population growth rate, is indeed positively and significantly correlated with the net rate of energy gain.
C1 UNIV TEXAS, DEPT ZOOL, AUSTIN, TX 78712 USA.
C3 University of Texas System; University of Texas Austin
NR 19
TC 117
Z9 136
U1 1
U2 51
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 153
EP 155
DI 10.1038/352153a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700055
DA 2026-03-10
ER

PT J
AU VANDERGOOT, FG
   GONZALEZMANAS, JM
   LAKEY, JH
   PATTUS, F
AF VANDERGOOT, FG
   GONZALEZMANAS, JM
   LAKEY, JH
   PATTUS, F
TI A MOLTEN-GLOBULE MEMBRANE-INSERTION INTERMEDIATE OF THE PORE-FORMING DOMAIN OF COLICIN-A
SO NATURE
LA English
DT Article
ID phospholipid monolayers; lipid bilayers; proteins; channel; state; peptide; translocation; mechanism; liposm; fragment
AB THE 'molten' globular conformation of a protein is compact with a native secondary structure but a poorly defined tertiary structure 1,2. Molten globular states are intermediates in protein folding and unfolding 3-5 and they may be involved in the translocation or insertion of proteins into membranes 6. Here we investigate the membrane insertion of the pore-forming domain of colicin A, a bacteriocin that depolarizes the cytoplasmic membrane of sensitive cells 7-9. We find that this pore-forming domain, the insertion of which depends on pH (refs 10, 11), undergoes a native to molten globule transition at acidic pH. The variation of the kinetic constant of membrane insertion of the protein into negatively charged lipid vesicles as a function of the interfacial pH correlates with the appearance of the acidic molten globular state, indicating that this state could be an intermediate formed during the insertion of colicin A into membranes.
RP VANDERGOOT, FG (corresponding author), EUROPEAN MOLEC BIOL LAB,MEYERHOFSTR 1,W-6900 HEIDELBERG,GERMANY.
NR 31
TC 414
Z9 436
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 408
EP 410
DI 10.1038/354408a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100056
PM 1956406
DA 2026-03-10
ER

PT J
AU PARESCE, F
   SHARA, M
   MEYLAN, G
   BAXTER, D
   GREENFIELD, P
   JEDRZEJEWSKI, R
   NOTA, A
   SPARKS, WB
   ALBRECHT, R
   BARBIERI, C
   BLADES, JC
   BOKSENBERG, A
   CRANE, P
   DEHARVENG, JM
   DISNEY, MJ
   JAKOBSEN, P
   KAMPERMAN, TM
   KING, IR
   MACCHETTO, F
   MACKAY, CD
   WEIGELT, G
AF PARESCE, F
   SHARA, M
   MEYLAN, G
   BAXTER, D
   GREENFIELD, P
   JEDRZEJEWSKI, R
   NOTA, A
   SPARKS, WB
   ALBRECHT, R
   BARBIERI, C
   BLADES, JC
   BOKSENBERG, A
   CRANE, P
   DEHARVENG, JM
   DISNEY, MJ
   JAKOBSEN, P
   KAMPERMAN, TM
   KING, IR
   MACCHETTO, F
   MACKAY, CD
   WEIGELT, G
TI BLUE STRAGGLERS IN THE CORE OF THE GLOBULAR-CLUSTER 47-TUCANAE
SO NATURE
LA English
DT Article
ID stellar collisions; stars; ngc-5466; systems
AB High-resolution observations of the core of the globular cluster 47 Tucanae with the Faint Object Camera on the Hubble Space Telescope reveal a high density of 'blue straggler' stars, occupying the upper end of the main sequence from which all stars in the cluster should have long since evolved. Their presence in the dense core supports the hypothesis that they formed by stellar collision and coalescence, and, as the heaviest objects in the cluster, have drifted to the core.
C1 EUROPEAN SPACE TECHNOL CTR,EUROPEAN SPACE AGCY,DEPT SPACE SCI,DIV ASTROPHYS,2200 AG NOORDWIJK,NETHERLANDS.
   SPACE TELESCOPE EUROPEAN COORDINATING FACIL,W-8046 GARCHING,GERMANY.
   OSSERV ASTRON PADOVA,I-35122 PADUA,ITALY.
   ROYAL GREENWICH OBSERV,CAMBRIDGE CB3 0EZ,ENGLAND.
   EUROPEAN SO OBSERV,W-8046 GARCHING,GERMANY.
   CNRS,ASTRON SPATIALE LAB,F-13012 MARSEILLE,FRANCE.
   SPACE RES INST,3584 CA UTRECHT,NETHERLANDS.
   UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720.
   UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND.
   MAX PLANCK INST RADIOASTRON,W-5300 BONN 1,GERMANY.
C3 European Space Agency; European Space Research & Technology Centre; University of Padua; Istituto Nazionale Astrofisica (INAF); University of Cambridge; European Southern Observatory; Centre National de la Recherche Scientifique (CNRS); University of California System; University of California Berkeley; University of Cambridge; Max Planck Society
RP PARESCE, F (corresponding author), SPACE TELESCOPE SCI INST,3700 SAN MARTIN DR,BALTIMORE,MD 21218, USA.
NR 26
TC 119
Z9 121
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 297
EP 301
DI 10.1038/352297a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900058
DA 2026-03-10
ER

PT J
AU IZPISUABELMONTE, JC
   TICKLE, C
   DOLLE, P
   WOLPERT, L
   DUBOULE, D
AF IZPISUABELMONTE, JC
   TICKLE, C
   DOLLE, P
   WOLPERT, L
   DUBOULE, D
TI EXPRESSION OF THE HOMEOBOX HOX-4 GENES AND THE SPECIFICATION OF POSITION IN CHICK WING DEVELOPMENT
SO NATURE
LA English
DT Article
ID retinoic acid; limb-bud; quantitative-analysis; pattern-formation; murine; morphogenesis; organization
AB The chicken Hox-4 homeogenes, like those of the mouse, are coordinately expressed in partially overlapping domains during wing development.  Local application of retinoic acid, a putative endogenous morphogen, induces de novo transcription of Hox-4 genes.  The mirror-image patterns of Hox-4 gene expression, which are obtained in this way, correlate with the subsequent development of mirror-image patterns of digits.  Hox-4 genes probably encode positional information.
C1 EUROPEAN MOLEC BIOL LAB,MEYERHOFSTR 1,POSTFACH 102209,W-6900 HEIDELBERG 1,GERMANY.
   UNIV COLL & MIDDLESEX SCH MED,DEPT ANAT & DEV BIOL,LONDON W1P 6DP,ENGLAND.
C3 European Molecular Biology Laboratory (EMBL); University of London; University College London
NR 26
TC 370
Z9 390
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 585
EP 589
DI 10.1038/350585a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200050
PM 1673231
DA 2026-03-10
ER

PT J
AU SPERGEL, DN
AF SPERGEL, DN
TI EVACUATION OF GAS FROM GLOBULAR-CLUSTERS BY WINDS FROM MILLISECOND PULSARS
SO NATURE
LA English
DT Article
ID hydrogen; search; evolution; nebula
AB WHY is so little gas observed within globular clusters?  A typical globular cluster contains approximately 10(3) post-turnoff stars, each of which will lose approximately 0.2 M. before its asymptotic giant branch phase of evolution, and approximately 0.1 M. during this phase 1, and so should accumulate 10(2) - 10(3) M. of gas in the 10(8)-year interval between passages of the globular cluster through the galactic disk.  (At each disk passage, gas ram pressure will remove the accumulated material 2,3.)  But observational searches show that there is scant intracluster gas; in many clusters, there is less than 1M. of gas, orders of magnitude less than theoretical predictions 3.  The recent discover 4,5 of multiple millisecond pulsars in globular clusters may resolve this long-standing problem:  the relativistic wind from these pulsars is enough to drive gas from stellar mass loss out of the globular cluster.
RP SPERGEL, DN (corresponding author), PRINCETON UNIV OBSERV,PRINCETON,NJ 08544, USA.
NR 28
TC 38
Z9 43
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 221
EP 222
DI 10.1038/352221a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500056
DA 2026-03-10
ER

PT J
AU SUES, HD
AF SUES, HD
TI VENOM-CONDUCTING TEETH IN A TRIASSIC REPTILE
SO NATURE
LA English
DT Article
AB I REPORT here the discovery of highly distinctive reptilian teeth of early Late Triassic age from the Newark Supergroup of Virginia 1, which are distinguished by the development of a deeply infolded median groove on both the labial and lingual surfaces of the blade-like crowns.  On the basis of the close structural similarity to comparable features in the two living species of the lizard Heloderma and on the poison-fangs in extant venomous snakes 2-5, it is suggested that these grooves functioned in venom conduction.  This would represent the earliest instance of the use of oral toxins among reptiles (comprising diapsids and turtles) recorded to date.
RP SUES, HD (corresponding author), NATL MUSEUM NAT HIST,DEPT PALEOBIOL,WASHINGTON,DC 20560, USA.
NR 9
TC 22
Z9 24
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 141
EP 143
DI 10.1038/351141a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500048
DA 2026-03-10
ER

PT J
AU JOHNSON, DW
   KILSBY, CG
   MCKENNA, DS
   SAUNDERS, RW
   JENKINS, GJ
   SMITH, FB
   FOOT, JS
AF JOHNSON, DW
   KILSBY, CG
   MCKENNA, DS
   SAUNDERS, RW
   JENKINS, GJ
   SMITH, FB
   FOOT, JS
TI AIRBORNE OBSERVATIONS OF THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE KUWAIT OIL SMOKE PLUME
SO NATURE
LA English
DT Article
ID carbonaceous smoke; fractal clusters
AB Airborne measurements in the densest part of the smoke plume at about 120km from the burning wells in Kuwait in late March 1991 showed typical particulate mass densities of 500-1,000-mu-g m-3, mixing ratios of 500-1,000 p.p.b.v. of sulphur dioxide and 30-60 p.p.b.v. of nitrogen oxides. One thousand kilometres from Kuwait, ozone concentrations in the plume exceeded background levels by about 50 p.p.b.v. The oil burn rate was estimated f rom sulphur fluxes to be 3.9 +/- 1.6 million barrels per day. Significant amounts of smoke were observed only below 5,000 m altitude, and the measured attenuation of solar radiation by the smoke was similar to those assumed in recent assessments.
C1 METEOROL OFF,BRACKNELL RB12 2SZ,BERKS,ENGLAND.
   ROYAL AEROSP ESTAB,METEOROL OFF,REMOTE SENSING INSTRUMENTAT,FARNBOROUGH GU14 6TD,HANTS,ENGLAND.
C3 Met Office - UK; Met Office - UK
RP JOHNSON, DW (corresponding author), ROYAL AEROSP ESTAB,METEOROL OFF,METEOROL RES FLIGHT,FARNBOROUGH GU14 6TD,HANTS,ENGLAND.
NR 19
TC 60
Z9 63
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 617
EP 621
DI 10.1038/353617a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200056
DA 2026-03-10
ER

PT J
AU BANCHEREAU, J
   ROUSSET, F
AF BANCHEREAU, J
   ROUSSET, F
TI GROWING HUMAN LYMPHOCYTES-B IN THE CD40 SYSTEM
SO NATURE
LA English
DT Article
ID cells
RP BANCHEREAU, J (corresponding author), SCHERING PLOUGH CORP, IMMUNOL RES LAB, 27 CHEMIN PEUPLIERS, BP 11, F-69571 DARDILLY, FRANCE.
NR 9
TC 185
Z9 200
U1 0
U2 11
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 678
EP 679
DI 10.1038/353678a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200077
PM 1717852
DA 2026-03-10
ER

PT J
AU BIANCONI, PA
   LIN, J
   STRZELECKI, AR
AF BIANCONI, PA
   LIN, J
   STRZELECKI, AR
TI CRYSTALLIZATION OF AN INORGANIC PHASE CONTROLLED BY A POLYMER MATRIX
SO NATURE
LA English
DT Article
ID stearic-acid monolayers; crystals; clusters; caco3
AB BIOLOGICAL composite materials such as bones, teeth and shells consist of a polymer matrix reinforced by an inorganic phase which forms in the matrix 1.  These materials are distinguished from synthetic composites by the high degree of organization and regularity displayed by the inorganic phase:  inorganic minerals of uniform size, morphology and crystallographic orientation can be formed in ordered arrays in living cells.  Such a process has until now not been realized in synthetic systems, although the recent interest in nanoscience 2-6 has stimulated much research in the area.  We report here an example of a synthetic process that produces composite materials analogous to those produced by natural biomineralization.  The inorganic/organic in situ synthesized composites display controlled inorganic crystal size, morphology and orientation, which are determining features of type II, or matrix-mediated 7, biocomposites.  The synthetic factors that must be optimized to give biomimetic properties to synthetic composites are strong binding of the inorganic reagents by the organic matrix (molecular complementarity); good 'solvation' of the inorganic reagents by the polymer; and an ordered, regular polymer environment in which to induce nucleation (matrix preorganization).
RP BIANCONI, PA (corresponding author), PENN STATE UNIV,DEPT CHEM,152 DAVEY LAB,UNIVERSITY PK,PA 16802, USA.
NR 21
TC 120
Z9 133
U1 1
U2 44
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 315
EP 317
DI 10.1038/349315a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100046
DA 2026-03-10
ER

PT J
AU SIGG, A
   NEFTEL, A
AF SIGG, A
   NEFTEL, A
TI EVIDENCE FOR A 50-PERCENT INCREASE IN H2O2 OVER THE PAST 200 YEARS FROM A GREENLAND ICE CORE
SO NATURE
LA English
DT Article
ID hydrogen-peroxide; system
AB HYDROGEN peroxide has attracted increasing attention from atmospheric chemists over the past decade, because in the gas phase it acts as a reservoir species of OH radicals 1,2, and in the aqueous phase it plays a key role in the oxidation of SO2 to H2SO4 in clouds 3.  It is also known to have an adverse effect on trees and plants 4.  In 1984, hydrogen peroxide was identified as one of the dominant trace species in polar ice 5, introducing the possibility of constructing a record of atmospheric hydrogen peroxide concentrations from ice-core data.  Here we present such a record for the past 700 years from Summit, Central Greenland.  We find that hydrogen peroxide concentrations have increased by 50% over the past 200 years, with most of the increase occurring in the past 20 years, indicating that human activities may be responsible for such a dramatic change.
RP SIGG, A (corresponding author), UNIV BERN,INST PHYS,SIDLERSTR 5,CH-3012 BERN,SWITZERLAND.
NR 13
TC 87
Z9 99
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 557
EP 559
DI 10.1038/351557a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400055
DA 2026-03-10
ER

PT J
AU PLANCHE, JP
   KING, HW
   KING, GN
AF PLANCHE, JP
   KING, HW
   KING, GN
TI A REFINERS APPROACH TO ASPHALT CHARACTERIZATION
SO NATURE
LA English
DT Article
C1 ELF ASPHALT INC LAB,TERRE HAUTE,IN 47807.
RP PLANCHE, JP (corresponding author), CTR RECH ELF SOLAIZE,BP 22,F-69360 ST SYMPHORIEN OZO,FRANCE.
NR 3
TC 0
Z9 0
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 24
EP 25
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100008
DA 2026-03-10
ER

PT J
AU RIELEY, G
   COLLIER, RJ
   JONES, DM
   EGLINTON, G
   EAKIN, PA
   FALLICK, AE
AF RIELEY, G
   COLLIER, RJ
   JONES, DM
   EGLINTON, G
   EAKIN, PA
   FALLICK, AE
TI SOURCES OF SEDIMENTARY LIPIDS DEDUCED FROM STABLE CARBON ISOTOPE ANALYSES OF INDIVIDUAL COMPOUNDS
SO NATURE
LA English
DT Article
ID atmospheric partial pressures; leaf starch; c-3 plants; discrimination; dioxide; ratio; photosynthesis; sugars; c-13
AB COMPOUND-Specific isotope analysis by gas chromatography combined with isotope-ratio mass spectrometry (GC-IRMS) 1,2 provides a new tool with which to study the carbon cycle at the molecular scale 3.  Previous studies 2,4 using this technique have been concerned with oceanic systems. Here we demonstrate that the potential for elucidating terrestrial sedimentary processes is equally important. By comparing the carbon isotope ratios (delta-C-13) of individual n-alkanes from the leaves of lakeside trees with those from the lake sediments, we are able to discriminate between the diverse sources of the sedimentary carbon. The leaf-wax n-alkanes show a large inter-species delta-C-13  variation of -30.1 to -38.7 parts per thousand, which may be the result of genetic differences in plant adaptation and physiology. Values of -30.1 to -35.9 parts per thousand were obtained for the corresponding n-alkanes extracted from the lake sediments, indicating that they derive from a mixed input of deciduous leaf waxes. Shorter-chain lipids in the sediments had delta-C-13 values of -20 to -22 parts per thousand, implying that these originate from a different (probably algal) source. Information of this sort goes beyond that which can be deduced from bulk isotope or biomarker analyses alone.
C1 SCOTTISH UNIV RES & REACTOR CTR,E KILBRIDE G75 0QU,LANARK,SCOTLAND.
C3 Scottish Universities Research & Reactor Center
RP RIELEY, G (corresponding author), UNIV BRISTOL,SCH CHEM,ORGAN GEOCHEM UNIT,CANTOCKS CLOSE,BRISTOL BS8 1TS,AVON,ENGLAND.
NR 20
TC 266
Z9 328
U1 1
U2 72
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 425
EP 427
DI 10.1038/352425a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600062
DA 2026-03-10
ER

PT J
AU PRASSIDES, K
   TOMKINSON, J
   CHRISTIDES, C
   ROSSEINSKY, MJ
   MURPHY, DW
   HADDON, RC
AF PRASSIDES, K
   TOMKINSON, J
   CHRISTIDES, C
   ROSSEINSKY, MJ
   MURPHY, DW
   HADDON, RC
TI VIBRATIONAL SPECTROSCOPY OF SUPERCONDUCTING K3C60 BY INELASTIC NEUTRON-SCATTERING
SO NATURE
LA English
DT Article
ID c-60
AB INTERCALATION of C60 (buckminsterfullerene 1,2) by alkali metals 3 leads to superconducting compounds of stoichiometry A3C60 (refs 4-6) with transition temperatures T(c) as high as 33 K (ref. 7). These transition temperatures are considerably higher than those for alkali-metal-intercalated graphite (< 0.6 K) 8 and scale with the size of the face-centred-cubic unit cell 9. Here we present the results of an inelastic neutron scattering study of the vibrational spectrum of the superconducting fulleride K3C60 (T(c) = 19.3 K). We find significant changes in the peak positions and intensities principally of the intramolecular H(g) vibrational modes, both in the high-energy tangential (130-200 meV) and the low-energy radial (approximately 50 meV) regions, compared with the vibrational spectrum of C60 (refs 10, 11).  Our results provide strong evidence for the importance of these modes in the pairing mechanism for superconductivity.
C1 RUTHERFORD APPLETON LAB,ISIS,DIV SCI,DIDCOT OX11 0QX,OXON,ENGLAND.
   AT&T BELL LABS,MURRAY HILL,NJ 07974.
C3 UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory; AT&T; Nokia Corporation; Nokia Bell Labs
RP PRASSIDES, K (corresponding author), UNIV SUSSEX,SCH CHEM & MOLEC SCI,BRIGHTON BN1 9QJ,E SUSSEX,ENGLAND.
NR 22
TC 127
Z9 127
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 462
EP 463
DI 10.1038/354462a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800053
DA 2026-03-10
ER

PT J
AU INGOLD, AL
   LANDEL, C
   KNALL, C
   EVANS, GA
   POTTER, TA
AF INGOLD, AL
   LANDEL, C
   KNALL, C
   EVANS, GA
   POTTER, TA
TI CO-ENGAGEMENT OF CD8 WITH THE T-CELL RECEPTOR IS REQUIRED FOR NEGATIVE SELECTION
SO NATURE
LA English
DT Article
ID protein kinase p56lck; i alpha-3 domain; transgenic mice; lymphocytes-t; recognition; deletion; molecule; antigen; self; substitution
AB ALTHOUGH it is established that the CD8 and CD4 co-receptors are involved in T-lymphocyte recognition and activation in the periphery, it is less clear whether these molecules participate in thymic selection events. Analysis of thymic selection in mice transgenic for T cell-receptor genes 1-4 or for major histocompatibility complex (MHC) genes 5, or mice injected with antibodies against CD8, CD4 or MHC molecules 6-8, is consistent with the participation of CD8 and CD4 in thymic selection. But antibody-mediated crosslinking of surface receptors in thymic organ cultures 9 has indicated that CD8 is not involved in thymic deletion. We show here that mice transgenic for a mutant MHC class I molecule that cannot interact with CD8 do not delete CD8-dependent T cells reactive with the wild-type molecule. This finding unequivocally establishes that for negative selection in the thymus, CD8 must interact with the same MHC class I molecule as the T cell receptor.
C1 UNIV COLORADO,HLTH SCI CTR,DEPT MICROBIOL & IMMUNOL,DENVER,CO 80206.
   UNIV COLORADO,HLTH SCI CTR,CTR CANC,DENVER,CO 80206.
   SALK INST BIOL STUDIES,MOLEC GENET LAB,SAN DIEGO,CA 92138.
C3 University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus; University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus; Salk Institute
RP INGOLD, AL (corresponding author), NATL JEWISH CTR IMMUNOL & RESP MED,DIV BASIC IMMUNOL,DENVER,CO 80206, USA.
NR 23
TC 85
Z9 87
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 721
EP 723
DI 10.1038/352721a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400060
PM 1908563
DA 2026-03-10
ER

PT J
AU PEDERSEN, J
   BJORNHOLM, S
   BORGGREEN, J
   HANSEN, K
   MARTIN, TP
   RASMUSSEN, HD
AF PEDERSEN, J
   BJORNHOLM, S
   BORGGREEN, J
   HANSEN, K
   MARTIN, TP
   RASMUSSEN, HD
TI OBSERVATION OF QUANTUM SUPERSHELLS IN CLUSTERS OF SODIUM ATOMS
SO NATURE
LA English
DT Article
ID electronic shell structure; metal-clusters
AB ATOMIC clusters of sodium and other simple metals are known to exhibit a shell structure, giving rise to enhanced stability at certain 'magic numbers' of constituent atoms 1-3. Balian and Bloch have shown 4 that such shells are the likely result of particularly stable electronic structures: electrons in a spherical cavity (approximating the potential in the clusters) follow semiclassical triangular or square orbits, leading to a shell structure similar to that in atoms 5, and stable configurations occur at magic numbers proportional to the cube root of the number of electrons. Balian and Bloch 4 also predicted that the existence of both triangular and square orbits, with slightly different periodicities of their magic numbers, should lead to a 'quantum beating' effect that imposes a low-frequency envelope on the periodic variation in cluster stability with increasing size, in effect creating an additional 'supershell' structure. Here we report the observation of this supershell effect in sodium clusters with up to 3,000 constituent atoms.
C1 MAX PLANCK INST FESTKORPERFORSCH,W-7000 STUTTGART 80,GERMANY.
C3 Max Planck Society
RP PEDERSEN, J (corresponding author), UNIV COPENHAGEN,NIELS BOHR INST,BLEGDAMSVEJ 17,DK-2100 COPENHAGEN,DENMARK.
NR 14
TC 202
Z9 208
U1 0
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 733
EP 735
DI 10.1038/353733a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600060
DA 2026-03-10
ER

PT J
AU COFER, WR
   LEVINE, JS
   WINSTEAD, EL
   STOCKS, BJ
AF COFER, WR
   LEVINE, JS
   WINSTEAD, EL
   STOCKS, BJ
TI NEW ESTIMATES OF NITROUS-OXIDE EMISSIONS FROM BIOMASS BURNING
SO NATURE
LA English
DT Article
ID trace gas emissions; climate change; combustion
AB ATMOSPHERIC nitrous oxide is important because of its role in stratospheric ozone destruction 1 and because it is a greenhouse gas. 2,3.  Measurements indicate that N2O is increasing in the atmosphere at a rate of approximately 0.2% yr-1 (ref. 4).  Fossil-fuel combustion and biomass burning 5,6 have been considered to be significant global sources of N2O, but the recent discovery of an artefact producing increased levels of N2O in combustion gas samples collected and stored in grab bottles before chemical analysis 7,8 has resulted in the downgrading of a fossil-fuel combustion and the questioning of biomass burning as important sources of N2O 9,10.  As almost all reported analyses of N2O produced from biomass burning have involved essentially the same collection and analysis protocols as used in the fossil-fuel studies, this source of N2O must also be re-examined.  Here we report and compare measurement of N2O made over a large prescribed fire using a near real-time in situ measurement technique with measurements of N2O from simultaneously collected grab-bottle samples.  The results from 27 small laboratory biomass test fires also help clarify the validity of earlier assessments.  We conclude that biomass burning contributes approximately 7% of atmospheric N2O, as opposed to earlier estimates of several times this value 6.
C1 ST SYST CORP,HAMPTON,VA 23666.
   FORESTRY CANADA,GREAT LAKES FORESTRY CTR,SAULT ST MARIE P6A 5M7,ONTARIO,CANADA.
C3 Natural Resources Canada; Canadian Forest Service
RP COFER, WR (corresponding author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665, USA.
NR 17
TC 40
Z9 42
U1 1
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 689
EP 691
DI 10.1038/349689a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700045
DA 2026-03-10
ER

PT J
AU WITTMANN, JC
   SMITH, P
AF WITTMANN, JC
   SMITH, P
TI HIGHLY ORIENTED THIN-FILMS OF POLY(TETRAFLUOROETHYLENE) AS A SUBSTRATE FOR ORIENTED GROWTH OF MATERIALS
SO NATURE
LA English
DT Article
ID polyethylene; polymers; orientation; mechanism; fibers
AB THE formation of highly oriented structures such as single crystals, single-domain liquid crystals and systems comprising uniaxially oriented crystallites is important in many applications of thin films and interfaces, ranging from materials reinforcement to molecular electronics. Of the methods that exist for forming such oriented structures, however, few have sufficient generality to make them applicable to materials of differing chemical composition or physical properties. Here we present a simple and surprisingly versatile method 1 for orienting a wide variety of crystalline and liquid-crystalline materials, including polymers, monomers and small organic and inorganic molecules. In our technique, a thin, single-crystal-like film of poly(tetrafluoroethylene) (PTFE) is deposited mechanically on a smooth substrate such as glass. Materials grown on this coated surface from solution, melt or vapour phases show a remarkable degree of alignment.
C1 UNIV CALIF SANTA BARBARA,DEPT CHEM & NUCL ENGN,SANTA BARBARA,CA 93106.
   ECOLE APPLICAT HAUTS POLYMERES,CTR RECH MACROMOLEC,INST CHARLES SADRON,6 RUE BOUSSINGAULT,F-67083 STRASBOURG,FRANCE.
C3 University of California System; University of California Santa Barbara
RP WITTMANN, JC (corresponding author), UNIV CALIF SANTA BARBARA,DEPT MAT,SANTA BARBARA,CA 93106, USA.
NR 28
TC 595
Z9 617
U1 4
U2 202
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 414
EP 417
DI 10.1038/352414a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600058
DA 2026-03-10
ER

PT J
AU ALTABET, MA
   DEUSER, WG
   HONJO, S
   STIENEN, C
AF ALTABET, MA
   DEUSER, WG
   HONJO, S
   STIENEN, C
TI SEASONAL AND DEPTH-RELATED CHANGES IN THE SOURCE OF SINKING PARTICLES IN THE NORTH-ATLANTIC
SO NATURE
LA English
DT Article
ID particulate organic-carbon; n-15 natural abundance; deep sargasso sea; amino-acids; food web; ocean; nitrogen; pacific; biovolume; biomass
AB LARGE, fast-sinking particles are important in the downward transport and redistribution of biogeochemical species in the deep ocean. Using nitrogen isotope ratio, N-15/N-14, as an in situ tracer, we investigate the source and transformation of these particles in the North Atlantic ocean. We observe seasonal variations in delta-N-15 associated with seasonal changes in near-surface nitrate concentration and particle flux; the nitrogen isotope variations are consistent with, but much larger than, previously observed variability 1,2.  Our results show that the signal from these near-surface changes propagates rapidly into the deep ocean, but is modified depending on the phase of the seasonal production cycle. Surprisingly, we find that delta-N-15 values for sinking particles decrease with depth during low-flux periods - behaviour that may occur generally in the open ocean. The sinking particles must therefore be either gaining light nitrogen or losing heavy nitrogen, an effect that we believe requires there to be another source of sinking particles, apart from recent surface production.
C1 INST MEERESKUNDE,W-2300 KIEL,GERMANY.
RP ALTABET, MA (corresponding author), WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543, USA.
NR 31
TC 216
Z9 245
U1 2
U2 46
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 136
EP 139
DI 10.1038/354136a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000055
DA 2026-03-10
ER

PT J
AU NICHOLLS, KW
   MAKINSON, K
   ROBINSON, AV
AF NICHOLLS, KW
   MAKINSON, K
   ROBINSON, AV
TI OCEAN CIRCULATION BENEATH THE RONNE ICE SHELF
SO NATURE
LA English
DT Article
AB THE intimate thermal contact between the base of Antarctic ice shelves and the underlying ocean enables changes in climate to have a rapid impact on the outflow of ice from the interior of Antarctica 1,2. Furthermore, water modified by passage under ice shelves, particularly in the Weddell Sea, is believed to be an important constituent of Antarctic Bottom Water 3 -a water mass that can be observed as far north as 50-degrees-N in the deep oceans 4. Antarctic Bottom Water is both cold and oxygen-rich, and plays an important part in the cooling and ventilation of the world's oceans. Because of the difficulty in gaining access, the oceanographic regime beneath ice shelves is very poorly sampled 5. By successfully drilling through the ice, however, we were able to obtain oceanographic data from beneath the largest Antarctic ice shelf, the Ronne-Filchner ice shelf in the southern Weddell Sea. We find that our data agree well with the predictions of a relatively simple oceanographic plume model of sub-ice-shelf circulation 6. This model can therefore be used with some confidence to investigate the links between climate changes, ice-shelf melting and bottom-water production.
RP NICHOLLS, KW (corresponding author), NERC, BRITISH ANTARCT SURVEY, HIGH CROSS, MADINGLEY RD, CAMBRIDGE CB3 0ET, ENGLAND.
NR 16
TC 44
Z9 48
U1 0
U2 7
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 221
EP 223
DI 10.1038/354221a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800046
DA 2026-03-10
ER

PT J
AU LEE, DW
AF LEE, DW
TI ULTRASTRUCTURAL BASIS AND FUNCTION OF IRIDESCENT BLUE COLOR OF FRUITS IN ELAEOCARPUS
SO NATURE
LA English
DT Article
ID plants; photosynthesis
AB IRIDESCENT colour, caused by physical effects (thin-film interference, diffraction and Tyndall scattering), is relatively common in animals but exceedingly rare among plants 1. Some benthic marine algae produce blue to violet iridescence 2,3, and the upper leaf surfaces of a few vascular plants from the shady environments of humid tropical forests are iridescent blue 4-6. Blue fruit colour has been assumed to be caused by anthocyanis 7. A survey of such fruits (26 species in 18 genera) in Costa Rica, India, Florida and Malaysia, showed this to be the case, except for the iridescent colour in fruits of Elaeocarpus angustifolius Blume (Elaeocarpaceae). There I show that the colour is caused by a remarkable structure in the epidermis, and provide evidence for its selective advantage.
C1 FAIRCHILD TROP GARDEN, MIAMI, FL 33156 USA.
RP LEE, DW (corresponding author), FLORIDA INT UNIV, DEPT BIOL SCI, UNIV PK, MIAMI, FL 33199 USA.
NR 30
TC 85
Z9 94
U1 2
U2 31
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 260
EP 262
DI 10.1038/349260a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900063
DA 2026-03-10
ER

PT J
AU BARNARD, SM
   WALT, DR
AF BARNARD, SM
   WALT, DR
TI A FIBEROPTIC CHEMICAL SENSOR WITH DISCRETE SENSING SITES
SO NATURE
LA English
DT Article
ID carbon-dioxide; fluorescence
AB A LONG-standing goal of clinical medicine has been the continuous, in situ measurement of solute concentrations (such as pH, pCO2 and pO2), particularly in blood.  Blood monitoring is accomplished at present by analysing discrete samples at a centralized, remote clinical laboratory, causing delays between sampling and analysis.  Most multi-analyte sensors developed for 'bedside' in situ monitoring 1 consist of several sensors fabricated into a sensor array or bundle 2,3.  This approach is not ideal where sensor size is an important factor.  Here we describe a technique that enables the development of a compact, multi-analyte fibre-optic chemical sensor.  The technique is based on localized photopolymerization of appropriate dye indicators on the face of an imaging fibre.  The sensing sites fluoresce to a degree controlled by analyte concentration, intensities being monitored simultaneously with an enhanced charge-coupled device (CCD) video camera.  We present results from a sensor that contains three individual pH-sensitive areas, and indicate how multi-analyte sensitivity may be achieved.
RP BARNARD, SM (corresponding author), TUFTS UNIV,DEPT CHEM,MAX TISHLER LAB ORGAN CHEM,MEDFORD,MA 02155, USA.
NR 15
TC 92
Z9 152
U1 1
U2 31
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 338
EP 340
DI 10.1038/353338a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400054
DA 2026-03-10
ER

PT J
AU NRIAGU, JO
   COKER, RD
   BARRIE, LA
AF NRIAGU, JO
   COKER, RD
   BARRIE, LA
TI ORIGIN OF SULFUR IN CANADIAN ARCTIC HAZE FROM ISOTOPE MEASUREMENTS
SO NATURE
LA English
DT Article
ID air-pollution; sulfur; aerosol
AB Since the mid-1950s, there has been a marked increase in levels of air pollution in the Arctic region 1-3.  This is apparent from the pervasive haze that has been detected over large areas of the Northern Hemisphere 3-6, which can cover up to 9% of the Earth's surface.  The haze is most pronounced during January to April, and is characterized by a reduction in visibility and anomalously high levels of organic and inorganic compounds of the type found in polluted environments 3,6,7. Most of the present knowledge about the origin of the chemical constituents of the haze comes from studies of elemental ratios and trajectory analyses 2,4,6,7.  Here we report the results of an analysis of the isotopic composition of sulphur in the Arctic haze.  We find that most the sulphur in the haze comes from Europe rather than from more local anthropogenic or biogenic sources, indicating that this form of air pollution becomes distributed globally.
C1 ATMOSPHER ENVIRONM SERV,TORONTO M3H 5T4,ONTARIO,CANADA.
C3 Environment & Climate Change Canada; Meteorological Service of Canada
RP NRIAGU, JO (corresponding author), NATL WATER RES INST BRANCH,BOX 5050,BURLINGTON L7R 4A6,ONTARIO,CANADA.
NR 32
TC 72
Z9 85
U1 2
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 142
EP 145
DI 10.1038/349142a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800052
DA 2026-03-10
ER

PT J
AU ADAMS, J
   WETMILLER, RJ
   HASEGAWA, HS
   DRYSDALE, J
AF ADAMS, J
   WETMILLER, RJ
   HASEGAWA, HS
   DRYSDALE, J
TI THE 1ST SURFACE FAULTING FROM A HISTORICAL INTRAPLATE EARTHQUAKE IN NORTH-AMERICA
SO NATURE
LA English
DT Article
AB Although many fault ruptures are known from the boundaries of the Earth's lithospheric plates, the 'stable' interiors of continents are much less active 1. Worldwide, only ten historical intraplate earthquakes are known to have produced surface faulting and none of these was in eastern North America. Despite the confirmed prehistoric rupture of the Meers fault 3, some have wondered if intraplate earthquakes in the stable North American craton might somehow be different from plate-boundary earthquakes, and hence fail to rupture the surface 4. This is an important consideration for seismic hazard assessments. When the Ungava earthquake (with magnitude (M(s)) 6.3 and apparent shallow depth) occurred on 25 December 1989 in northern Canada, we (and, independently, A. Johnston of Memphis State University) concluded that it might have produced surface faulting. Here we report that there was indeed a surface rupture, 8.5 km long, with up to 1.8 m of reverse faulting on a steeply dipping, arcuate fault plane. The faulting confirms the seismological process and indicates that there is a hazard from ground-rupturing earthquakes in eastern North America, but the poor surface expression shows that finding prehistoric fault ruptures in order to constrain seismic hazard estimates will be difficult.
RP ADAMS, J (corresponding author), GEOL SURVEY CANADA, DIV GEOPHYS, 1 OBSERV CRESCENT, OTTAWA K1A OY3, ONTARIO, CANADA.
NR 16
TC 78
Z9 84
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 617
EP 619
DI 10.1038/352617a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100054
DA 2026-03-10
ER

PT J
AU OHTSUKI, YH
   OFURUTON, H
AF OHTSUKI, YH
   OFURUTON, H
TI PLASMA FIREBALLS FORMED BY MICROWAVE INTERFERENCE IN AIR
SO NATURE
LA English
DT Article
AB DESPITE many experimental and theoretical studies, a widely accepted explanation of ball lightning has yet to be found.  It is possible, however, that ball lightning is created by the interaction of different types of energy in the atmosphere 1.  Indeed, the production of a fireball by an electric discharge in an atmosphere containing dilute fuel gases such as propane has been reported 2.  We have also managed to produce several types of fireball by setting off electric discharges in an atmosphere containing aerosol with varying concentrations of ethane and/or methane 3.  Here we report the production of plasma fireballs in a natural atmosphere by microwave interference.  The fireballs exhibited certain properties that match eyewitness observations of ball lightning, such as motion against the wind and the ability to pass through a wall intact.
C1 TOKYO METROPOLITAN COLL AERONAUT ENGN,ARAKAWA KU,TOKYO 116,JAPAN.
RP OHTSUKI, YH (corresponding author), WASEDA UNIV,DEPT PHYS,OKUBO 3,SHINJUKU KU,TOKYO 169,JAPAN.
NR 15
TC 75
Z9 80
U1 0
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 139
EP 141
DI 10.1038/350139a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500051
DA 2026-03-10
ER

PT J
AU DIEKMANN, D
   BRILL, S
   GARRETT, MD
   TOTTY, N
   HSUAN, J
   MONFRIES, C
   HALL, C
   LIM, L
   HALL, A
AF DIEKMANN, D
   BRILL, S
   GARRETT, MD
   TOTTY, N
   HSUAN, J
   MONFRIES, C
   HALL, C
   LIM, L
   HALL, A
TI BCR ENCODES A GTPASE-ACTIVATING PROTEIN FOR P21RAC
SO NATURE
LA English
DT Article
ID ras p21; gene-product; escherichia-coli; gap; leukemia; domain; cells; cdna; identification; interacts
AB MORE than thirty small guanine nucleotide-binding proteins related to the ras-encoded oncoprotein, termed Ras or p21ras, are known 1.  They regulate many fundamental processes in all eukaryotic cells, such as growth, vesicle traffic and cytoskeletal organization. GTPase-activating proteins (GAPs) accelerate the intrinsic rate of GTP hydrolysis of Ras-related proteins, leading to down-regulation of the active GTP-bound form 2.  For p21ras, two GAP proteins are known, rasGAP and the neurofibromatosis (NF1) gene product 2-5.  There is evidence that rasGAP may also be a target protein for regulation by Ras and be involved in downstream signalling 6-8.  We have purified a GAP protein for p21rho, which is involved in the regulation of the actin cytoskeleton 9. Partial sequencing of rhoGAP reveals significant homology with the product of the bcr (breakpoint cluster region) gene, the translocation breakpoint in Philadelphia chromosome-positive chronic myeloid leukaemias.  We show here that the carboxy-terminal domains of the bcr-encoded protein (Bcr) and of a Bcr-related protein, n-chimaerin, are both GAP proteins for the Ras-related GTP-binding protein, p21rac.  This result suggests that Bcr could be a target for regulation by Rac and has important new implications for the role of bcr translocations in leukaemia.
C1 INST CANC RES,CHESTER BEATTY LABS,237 FULHAM RD,LONDON SW3 6JB,ENGLAND.
   LUDWIG INST CANC RES,LONDON W1P 8BT,ENGLAND.
   INST NEUROL,LONDON WC1 1PJ,ENGLAND.
C3 University of London; Institute of Cancer Research - UK; Royal Marsden NHS Foundation Trust; Ludwig Institute for Cancer Research; University of London; University College London
NR 29
TC 422
Z9 484
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 400
EP 402
DI 10.1038/351400a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600056
PM 1903516
DA 2026-03-10
ER

PT J
AU DESAI, KM
   SESSA, WC
   VANE, JR
AF DESAI, KM
   SESSA, WC
   VANE, JR
TI INVOLVEMENT OF NITRIC-OXIDE IN THE REFLEX RELAXATION OF THE STOMACH TO ACCOMMODATE FOOD OR FLUID
SO NATURE
LA English
DT Article
ID l-arginine; glyceryl trinitrate; guanylate-cyclase; methylene-blue; stimulation; nitroprusside; inhibitor; muscle
AB THE fundus of the guinea-pig stomach actively dilates in response to low increases in intragastric pressure 1. This physiological response, now called adaptive relaxation 2,3, accommodates the intake of liquid or food. It is independent of external innervation, resistant to ganglion blockade, but reflex in origin. The nerves involved are neither adrenergic nor cholinergic in nature. Non-adrenergic, non-cholinergic (NANC) nerves have now been recognized in many parts of the gastrointestinal tract 4 and have recently been linked with release of nitric oxide (NO) on electrical stimulation 5-7. Here we show that adaptive relaxation in isolated stomach of the guinea pig is mediated by a NANC neurotransmitter substance indistinguishable from NO derived from L-arginine 8. This is substantiated by inhibition of adaptive relaxation by N(G)-monomethyl-L-arginine or N-omega-nitro-L-arginine methyl ester, both inhibitors of NO synthesis 9,10, and by methylene blue, an inhibitor of soluble guanylate cyclase 11. There are two distinct neuronal pathways signalling NO-dependent adaptive relaxation, as evidenced by tetrodotoxin sensitivity. The first is a local reflex arc, the afferent fibres of which sense changes in intragastric pressure. The second is stimulated by an agonist for ganglionic nicotinic receptors. Thus, the functional significance of NO release from NANC nerves in the stomach is to bring about adaptive relaxation through a reflex response to increases in intragastric pressure.
C1 ST BARTHOLOMEWS HOSP, COLL MED, WILLIAM HARVEY RES INST, LONDON EC1M 6BQ, ENGLAND.
C3 University of London; Queen Mary University London
NR 18
TC 516
Z9 537
U1 0
U2 12
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 477
EP 479
DI 10.1038/351477a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800054
PM 1675430
DA 2026-03-10
ER

PT J
AU NUNEZ, G
   HOCKENBERY, D
   MCDONNELL, TJ
   SORENSEN, CM
   KORSMEYER, SJ
AF NUNEZ, G
   HOCKENBERY, D
   MCDONNELL, TJ
   SORENSEN, CM
   KORSMEYER, SJ
TI BCL-2 MAINTAINS B-CELL MEMORY
SO NATURE
LA English
DT Article
ID antigen-driven selection; immunological memory; germinal-centers; bone-marrow; secondary; expression; survival; mice; population; responses
AB THE number of lymphocytes in an animal is remarkably constant despite antigen-driven proliferation and a high rate of B-cell lymphopoiesis. This reflects the relatively brief lifespan of many newly generated B cells and argues for a well-regulated death mechanism 1-3.  Even so, a secondary immune response can be generated years after a primary exposure to antigen 4.  Antigen that might restimulate B cells persists for extended periods on follicular dendritic cells in the light zone of germinal centres 5-13.  Antigen binding B cells have also been found months after the end of obvious cell division 14.  The precise signal that enables certain B cells to emerge as long-term surviving memory cells 14-17 is unknown. Bcl-2, an inner mitochondrial membrane protein 18, blocks programmed cell death in B cells 18-20.  We report here that this proto-oncogene maintains immune responsiveness. Transgenic mice overproducing Bcl-2 have a long-term persistence of immunoglobulin-secreting cells and an extended lifetime for memory B cells.
C1 WASHINGTON UNIV,SCH MED,DEPT MED,ST LOUIS,MO 63110.
   WASHINGTON UNIV,SCH MED,DEPT PATHOL,ST LOUIS,MO 63110.
   WASHINGTON UNIV,SCH MED,DEPT MOLEC MICROBIOL,ST LOUIS,MO 63110.
C3 Washington University (WUSTL); Washington University (WUSTL); Washington University (WUSTL)
RP NUNEZ, G (corresponding author), WASHINGTON UNIV,SCH MED,HOWARD HUGHES MED INST,ST LOUIS,MO 63110, USA.
NR 28
TC 217
Z9 226
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 71
EP 73
DI 10.1038/353071a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500060
PM 1908951
DA 2026-03-10
ER

PT J
AU LEE, C
   LEVITT, M
AF LEE, C
   LEVITT, M
TI ACCURATE PREDICTION OF THE STABILITY AND ACTIVITY EFFECTS OF SITE-DIRECTED MUTAGENESIS ON A PROTEIN CORE
SO NATURE
LA English
DT Article
ID free-energy calculations; t4 lysozyme; staphylococcal nuclease; hydrophobic core; packing; thermostability; repressor
AB THEORETICAL prediction of the structure, stability and activity of proteins, an important unsolved problem in molecular biology, would be of use for guiding site-directed mutagenesis and other protein-engineering techniques. X-ray diffraction studies have provided extensive structural information for many proteins, challenging theorists to develop reliable techniques able to use such knowledge as a base for prediction of mutants' characteristics. Here we report theoretical calculation of stabilization energies for 78 triple-site sequence variants of lambda-repressor characterized experimentally by Lim and Sauer 1.  The calculated energies correlate with the mutants' measured activities; active and inactive mutations are discriminated with 92% reliability. They correlate even more directly with the mutants' thermostabilities, correctly identifying two of the mutants to be more stable than the wild type.
RP LEE, C (corresponding author), STANFORD UNIV,MED CTR,DEPT CELL BIOL,BECKMAN LABS STRUCT BIOL,STANFORD,CA 94305, USA.
NR 19
TC 165
Z9 196
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 448
EP 451
DI 10.1038/352448a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600071
PM 1861725
DA 2026-03-10
ER

PT J
AU RUSTGI, AK
   DYSON, N
   BERNARDS, R
AF RUSTGI, AK
   DYSON, N
   BERNARDS, R
TI AMINO-TERMINAL DOMAINS OF C-MYC AND N-MYC PROTEINS MEDIATE BINDING TO THE RETINOBLASTOMA GENE-PRODUCT
SO NATURE
LA English
DT Article
ID adenovirus e1a proteins; dna-binding; susceptibility gene; transformation; oncoproteins; mutations; oncogenes; regions
AB THE proteins encoded by the myc gene family are involved in the control of cell proliferation and differentiation, and aberrant expression of myc proteins has been implicated in the genesis of a variety of neoplasms 1.  In the carboxyl terminus, myc proteins have two domains that encode a basic domain/helix-loop-helix and a leucine zipper motif, respectively. These motifs are involved both in DNA binding and in protein dimerization 2-5.  In addition, myc protein family members share several regions of highly conserved amino acids in their amino termini that are essential for transformation 6,7.  We report here that an N-terminal domain present in both the c-myc and N-myc proteins mediates binding to the retinoblastoma gene product, pRb. We show that the human papilloma virus E7 protein competes with c-myc for binding to pRb, indicating that these proteins share overlapping binding sites on pRb. Furthermore, a mutant Rb protein from a human tumour cell line that carried a 35-amino-acid deletion in its C terminus failed to bind to c-myc. Our results suggest that c-myc and pRb cooperate through direct binding to control cell proliferation.
C1 MASSACHUSETTS GEN HOSP,CTR CANC,DIV MOLEC ONCOL,BOSTON,MA 02150.
   MASSACHUSETTS GEN HOSP,GASTROINTESTINAL UNIT,BOSTON,MA 02150.
   HARVARD UNIV,SCH MED,BOSTON,MA 02115.
C3 Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; Harvard University; Harvard Medical School
RP RUSTGI, AK (corresponding author), MASSACHUSETTS GEN HOSP,CTR CANC,DIV MOLEC GENET,149 13TH ST,BOSTON,MA 02150, USA.
NR 27
TC 327
Z9 335
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 541
EP 544
DI 10.1038/352541a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600067
PM 1865909
DA 2026-03-10
ER

PT J
AU LEOVY, CB
   FRIEDSON, AJ
   ORTON, GS
AF LEOVY, CB
   FRIEDSON, AJ
   ORTON, GS
TI THE QUASIQUADRENNIAL OSCILLATION OF JUPITER EQUATORIAL STRATOSPHERE
SO NATURE
LA English
DT Article
ID quasi-biennial oscillation; semiannual oscillation; middle atmosphere; evolution; waves; cycle; model
AB A NEW 11-year record of Jupiter's stratospheric temperature 1 shows an equatorial temperature oscillation with an apparent period of 4-5 years. Here we compare this oscillation to two long-period oscillations of zonal winds in the Earth's equatorial stratosphere, and propose that the same mechanism-forcing by the stresses of vertically propagating waves-is responsible for the oscillations on both planets. Jupiter's temperature oscillation has been observed for slightly more than two cycles and closely resembles the temperature signatures of the Earth's semiannual oscillation and quasibiennial oscillation. If the mechanisms responsible for these oscillations are indeed similar, Jupiter's oscillation indicates that there is significant vertical momentum transport due to equatorially trapped atmospheric waves, and it may provide a means for probing the poorly understood process of the generation of these waves by convection 2,3.
C1 CALTECH,JET PROP LAB,PASADENA,CA 91109.
C3 National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology
RP LEOVY, CB (corresponding author), UNIV WASHINGTON,DEPT ATMOSPHER SCI,SEATTLE,WA 98195, USA.
NR 15
TC 106
Z9 114
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 380
EP 382
DI 10.1038/354380a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100046
DA 2026-03-10
ER

PT J
AU FORSBURG, SL
   NURSE, P
AF FORSBURG, SL
   NURSE, P
TI IDENTIFICATION OF A G1-TYPE CYCLIN PUC1+ IN THE FISSION YEAST SCHIZOSACCHAROMYCES-POMBE
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; cell-cycle; mating-pheromone; dna-replication; messenger-rna; control gene; m-phase; mitosis; protein; division
AB IN rapidly growing cells of the budding yeast Saccharomyces cerevisiae, the cell cycle is regulated chiefly at Start, just before the G1-S boundary 1, whereas in the fission yeast Schizosaccharomyces pombe, the cycle is predominantly regulated at G2-M (ref. 2). Both control points are present in both yeasts, and both require the p34cdc2 protein kinase 3-5. At G2-M, p34cdc2 kinase activity in S. pombe requires a B-type cyclin in a complex with p34cdc2 (refs 6-14); this complex is the same as MPF (maturation promoting factor 15,16). The p34cdc2 activity at the G1-S transition in S. cerevisiae may be regulated by a similar cyclin complex, using one of the product of a new class of cyclin genes (CLN1, CLN2 and WHI1 (DAF1/CLN3)) (refs 17-22). At least one is required for progression through the G1-S phase, and deletion of all three leads to G1 arrest 19. WHI1 was isolated as a dominant allele causing budding yeast cells to divide at a reduced size 21 and was later independently identified as DAF1, a dominant allele of which rendered the cells refractory to the G1-arrest induced by the mating pheromone alpha-factor 22. The dominant alleles are truncations thought to yield proteins of increased stability, and the cells are accelerated through G1 (refs 20, 22). Without WHI1 function, the cells are hypersensitive to alpha-factor 22, enlarged and delayed in G1 (refs 20, 22). Heretofore, this G1-class of cyclins has not been identified in other organisms. We have isolated a G1-type cyclin gene called puc1+ from S. pombe, using a functional assay in S. cerevisiae. Expression of puc1+ in S. pombe indicates that it has a cyclin-like role in the fission yeast distinct from the role of the B-type mitotic cyclin.
RP FORSBURG, SL (corresponding author), UNIV OXFORD, DEPT BIOCHEM,MICROBIOL UNIT,IMPERIAL CANC RES FUND, CELL CYCLE GRP, S PARKS RD, OXFORD OX1 3QU, ENGLAND.
NR 32
TC 87
Z9 95
U1 0
U2 7
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 245
EP 248
DI 10.1038/351245a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000061
PM 1828291
DA 2026-03-10
ER

PT J
AU MEYER, E
   HOWALD, L
   OVERNEY, RM
   HEINZELMANN, H
   FROMMER, J
   GUNTHERODT, HJ
   WAGNER, T
   SCHIER, H
   ROTH, S
AF MEYER, E
   HOWALD, L
   OVERNEY, RM
   HEINZELMANN, H
   FROMMER, J
   GUNTHERODT, HJ
   WAGNER, T
   SCHIER, H
   ROTH, S
TI MOLECULAR-RESOLUTION IMAGES OF LANGMUIR-BLODGETT-FILMS USING ATOMIC FORCE MICROSCOPY
SO NATURE
LA English
DT Article
AB THE ability to prepare thin films of amphiphilic molecules (Langmuir-Blodgett (LB) films) is valuable to many areas of research. In biology they provide models for ideal membranes; the two-dimensional behaviour and structural phase transitions are of fundamental interest in surface physics; and their tribological characteristics suggest potential engineering applications.  For determining the structure of these films, the common techniques such as X-ray and neutron scattering are limited to thick (greater-than-or-similar-to 200 angstrom) multilayers.  Thinner films can be studied by transmission electron microscopy and low-energy electron diffraction 1,2, but these electron-beam techniques tend to damage thin films.  More recently, the scanning tunnelling microscope 3 has provided a non-destructive means of investigating the structures of LB films 4-6, but as the films are insulating, the interpretation of such images has been controversial. The atomic force microscope 7 is not plagued with these ambiguities, as it does not require a conductive sample.  Here we present images, with molecular resolution, of LB films of cadmium arachidate deposited on an amorphous silicate substrate.  Despite the disorder in the substrate, the films display a periodic structure over large distances (several hundreds of angstroms).  This suggests that the adsorbed molecules near the interface are driven to self-assemble primarily, if not solely, by intermolecular forces rather than by dependence on substrate periodicity.
C1 IBM CORP,ALMADEN RES LAB,SAN JOSE,CA 95120.
   MAX PLANCK INST FESTKORPERFORSCH,W-7000 STUTTGART 80,GERMANY.
C3 International Business Machines (IBM); IBM USA; Max Planck Society
RP MEYER, E (corresponding author), UNIV BASEL,INST PHYS,KLINGELBERGSTR 82,CH-4056 BASEL,SWITZERLAND.
NR 25
TC 224
Z9 229
U1 0
U2 51
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 398
EP 400
DI 10.1038/349398a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400043
DA 2026-03-10
ER

PT J
AU YOOL, AJ
   SCHWARZ, TL
AF YOOL, AJ
   SCHWARZ, TL
TI ALTERATION OF IONIC SELECTIVITY OF A K+ CHANNEL BY MUTATION OF THE H5 REGION
SO NATURE
LA English
DT Article
ID potassium channels; shaker locus; xenopus oocytes; drosophila; brain; cdna; expression; cations; cloning
AB THE high ionic selectivity of K+ channels is a unifying feature of this diverse class of membrane proteins.  Though K+ channels differ widely in regulation and kinetics, physiological studies have suggested a common structure:  a single file pore containing mulitiple ion-binding sites and having broader vestibules at both ends 1-5.  We have used site-directed mutagenesis and single-channel recordings to identify a molecular region that influences ionic selectivity in a cloned A-type K+ channel from Drosophila.  Single amino-acid substitutions in H5, the fifth hydrophobic region 6, enhanced the passage of NH4+ and Rb+, ions with diameters larger than K+, without compromising the ability of the channel to exclude the smaller cation, Na+.  The mutations that substantially altered selectivity had little effect on the gating properties of the channel.  We conclude that the H5 region is likely to line the pore of the K+ channel.
RP YOOL, AJ (corresponding author), STANFORD UNIV,MED CTR,DEPT MOLEC & CELLULAR PHYSIOL,STANFORD,CA 94305, USA.
NR 25
TC 376
Z9 399
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 700
EP 704
DI 10.1038/349700a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700049
PM 1899917
DA 2026-03-10
ER

PT J
AU TRAMIER, B
AF TRAMIER, B
TI ELF-AQUITAINE AND THE ENVIRONMENT
SO NATURE
LA English
DT Article
RP TRAMIER, B (corresponding author), ELF AQUITAINE,ENVIRONM AFFAIRS,F-92078 PARIS,FRANCE.
NR 0
TC 0
Z9 0
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 4
EP 4
DI 
PG 1
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100003
DA 2026-03-10
ER

PT J
AU FRANKEL, WN
   RUDY, C
   COFFIN, JM
   HUBER, BT
AF FRANKEL, WN
   RUDY, C
   COFFIN, JM
   HUBER, BT
TI LINKAGE OF MLS GENES TO ENDOGENOUS MAMMARY-TUMOR VIRUSES OF INBRED MICE
SO NATURE
LA English
DT Article
ID induced immunodeficiency syndrome; chromosomal distribution; mouse chromosome-1; retrovirus; loci; gr; determinants; segregation; expression; induction
AB T CELLS that recognize self antigen are clonally deleted in the thymus-a maturation process that occurs in the context of histocompatibility molecules and the T-cell receptor.  The minor lymphocyte stimulation antigens (Mls) effect these deletions through interactions with the V-beta portion of the T-cell receptor, thus mimicking bacterial 'superantigens'.  Intrigued by the fact that each known Mls gene maps to the same chromosomal region as an endogenous mouse mammary tumour virus (Mtv), we reevaluated the linkage relationships between the two gene families.  Here we report perfect concordance in inbred and recombinant inbred mice between the presence of four Mtv proviruses with the expression of Mls gene products.  These data suggest a general model in which mammary tumour virus gene products themselves are the ligands that shape a considerable portion of the immunological repertoire of common laboratory mice.
C1 TUFTS UNIV,SCH MED,DEPT PATHOL,BOSTON,MA 02111.
   TUFTS UNIV,SCH MED,DEPT MOLEC BIOL,BOSTON,MA 02111.
C3 Tufts University; Tufts University
NR 41
TC 369
Z9 373
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 526
EP 528
DI 10.1038/349526a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100067
PM 1846948
DA 2026-03-10
ER

PT J
AU HUA, QX
   SHOELSON, SE
   KOCHOYAN, M
   WEISS, MA
AF HUA, QX
   SHOELSON, SE
   KOCHOYAN, M
   WEISS, MA
TI RECEPTOR-BINDING REDEFINED BY A STRUCTURAL SWITCH IN A MUTANT HUMAN INSULIN
SO NATURE
LA English
DT Article
AB CRYSTAL Structures of insulin have been determined in various distinct forms 1-5, the relevance of which to receptor recognition has long been the subject of speculation 2,6,7. Recently the crystal structure of an inactive insulin analogue has been determined and, surprisingly, found to have a conformation identical to native insulin 8,9. On this basis Dodson and colleagues have suggested that the known insulin crystal structures reflect an inactive conformation, and that a change in conformation is required for activity-specifically, the carboxy terminal residues of the B-chain are proposed to separate from the amino terminal residues of the A-chain 8. Here we report the solution structure of an active insulin mutant 7,10, determined by two-dimensional NMR, which supports this hypothesis. In the mutant, the carboxy terminal beta-turn and beta-strand of the B-chain are destabilized and do not pack across the rest of the molecule. We suggest that analogous detachment of the carboxy terminal region of the B-chain occurs in native insulin on binding to its receptor. Our finding that partial unfolding of the B-chain exposes an alternative protein surface rationalizes the receptor-binding properties of a series of anomalous insulin analogues 7,11-13, including a mutant insulin associated with diabetes mellitus in man 14,15.
C1 MASSACHUSETTS GEN HOSP, DEPT MED, BOSTON, MA 02114 USA.
   CHINESE ACAD SCI, INST BIOPHYS, BEIJING, PEOPLES R CHINA.
   BRIGHAM & WOMENS HOSP, JOSLIN DIABET CTR, BOSTON, MA 02115 USA.
   BRIGHAM & WOMENS HOSP, DEPT MED, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, DEPT MED, BOSTON, MA 02115 USA.
   CNRS, UA 32, F-91128 PALAISEAU, FRANCE.
C3 Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; Chinese Academy of Sciences; Institute of Biophysics, CAS; Harvard University; Harvard University Medical Affiliates; Joslin Diabetes Center, Inc.; Brigham & Women's Hospital; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical School; Centre National de la Recherche Scientifique (CNRS)
NR 30
TC 237
Z9 270
U1 0
U2 16
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 238
EP 241
DI 10.1038/354238a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800052
PM 1961250
DA 2026-03-10
ER

PT J
AU DELGENIO, AD
   LACIS, AA
   RUEDY, RA
AF DELGENIO, AD
   LACIS, AA
   RUEDY, RA
TI SIMULATIONS OF THE EFFECT OF A WARMER CLIMATE ON ATMOSPHERIC HUMIDITY
SO NATURE
LA English
DT Article
ID feedback; models; co2
AB THE increases in the concentration of water vapour constitute the single largest positive feedback in models of global climate warming caused by greenhouse gases 1,2.  It has been suggested 3-5 that sinking air in the regions surrounding deep cumulus clouds will dry the upper troposphere and eliminate or reverse the direction of water vapour feedback.  We have now tested this hypothesis by performing an idealized simulation of climate change with two different versions of a climate model.  The versions differ in their parameterizations of moist convection and stratiform clouds, but both incorporate the drying due to subsidence of clear air.  Despite increased drying of the upper troposphere by cumulus clouds, upper-level humidity increases in the warmer climate because of enhanced upward moisture transport by the general circulation and increased accumulation of water vapour and ice at cumulus cloud tops.  The model behaviour is consistent with recent satellite estimates of the water vapour feedback 6,7.
RP DELGENIO, AD (corresponding author), NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025, USA.
NR 20
TC 66
Z9 82
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 382
EP 385
DI 
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600050
DA 2026-03-10
ER

PT J
AU HEEMSKERK, J
   DINARDO, S
   KOSTRIKEN, R
   OFARRELL, PH
AF HEEMSKERK, J
   DINARDO, S
   KOSTRIKEN, R
   OFARRELL, PH
TI MULTIPLE-MODES OF ENGRAILED REGULATION IN THE PROGRESSION TOWARDS CELL FATE DETERMINATION
SO NATURE
LA English
DT Article
ID segment-polarity gene; drosophila embryos; developmental compartmentalization; auto-regulation; wingless gene; expression; localization; transcripts; protein; locus
AB The engrailed gene product of Drosophila specifies the fate of a subset of cells in each segment. Our studies of engrailed regulation suggest that fate determination is an elaborate, multistep process. At the time in embryogenesis when the engrailed-dependent cell fate is probably determined, four modes of control act in an overlapping progression to govern engrailed expression. After activation by pair-rule genes, both an extracellular signal, wingless, and autoregulation are required for engrailed expression. Autoregulation graduates to wingless independence, but is transient, and is superseded by an engrailed- independent mode of maintenance.
C1 ROCKEFELLER UNIV, NEW YORK, NY 10021 USA.
   UNIV CALIF BERKELEY, DEPT MOLEC & CELL BIOL, BERKELEY, CA 94720 USA.
C3 Rockefeller University; University of California System; University of California Berkeley
RP HEEMSKERK, J (corresponding author), UNIV CALIF SAN FRANCISCO, SCH MED, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA.
FU NIGMS NIH HHS [R01 GM037193] Funding Source: Medline
NR 33
TC 246
Z9 261
U1 0
U2 6
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 404
EP 410
DI 10.1038/352404a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600055
PM 1861720
DA 2026-03-10
ER

PT J
AU STROBEL, SA
   DERVAN, PB
AF STROBEL, SA
   DERVAN, PB
TI SINGLE-SITE ENZYMATIC CLEAVAGE OF YEAST GENOMIC DNA MEDIATED BY TRIPLE HELIX FORMATION
SO NATURE
LA English
DT Article
ID gel-electrophoresis; saccharomyces-cerevisiae; sequence; endonuclease; recognition; separation; proteins; maturase; binding
AB PHYSICAL mapping of chromosomes would be facilitated by methods of breaking large DNA into manageable fragments, or cutting uniquely at genetic markers of interest.  Key issues in the design of sequence-specific DNA cleaving reagents are the specificity of binding, the generalizability of the recognition motif, and the cleavage yield.  Oligonucleotide-directed triple helix formation is a generalizable motif for specific binding to sequences longer than 12 base pairs within DNA of high complexity 1-3.  Studies with plasmid DNA show that triple helix formation can limit the operational specificity of restriction enzymes to endonuclease recognition sequences that overlap oligonucleotide-binding sites 4,5.  Triple helix formation, followed by methylase protection, triple helix-disruption, and restriction endonuclease digestion produces near quantitative cleavage at the single overlapping triple helix-endonuclease site 4,5.  As a demonstration that this technique may be applicable to the orchestrated cleavage of large genomic DNA, we report the near quantitative single-site enzymatic cleavage of the Saccharomyces cerevisiae genome mediated by triple helix formation.  The 340-kilobase yeast chromosome III was cut uniquely at an overlapping homopurine-EcoRI target site 27 base pairs long to produce two expected cleavage products of 110 and 230 kilobases.  No cleavage of any other chromosome  was detected.  The potential generalizability of this technique, which is capable of near quantitative cleavage at a single site in at lease 14 megabase pairs of DNA, could enable selected regions of chromosomal DNA to be isolated without extensive screening of genomic libraries.
C1 CALTECH,DIV CHEM & CHEM ENGN,PASADENA,CA 91125.
C3 California Institute of Technology
NR 27
TC 136
Z9 158
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 172
EP 174
DI 10.1038/350172a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500066
PM 1848684
DA 2026-03-10
ER

PT J
AU NAUMANN, D
   HELM, D
   LABISCHINSKI, H
AF NAUMANN, D
   HELM, D
   LABISCHINSKI, H
TI MICROBIOLOGICAL CHARACTERIZATIONS BY FT-IR SPECTROSCOPY
SO NATURE
LA English
DT Article
AB Infrared signals of microorganisms are highly specific fingerprint-like patterns that can be used for probing the identity of microorganisms.  The simplicity and versatility of Fourier-transform infrared spectroscopy (FT-IR) makes it a versatile technique for rapid differentiation, classification, identification and large-scale screening at the subspecies level.
RP NAUMANN, D (corresponding author), BUNDESGESUNDHEITSAMT,ROBERT KOCH INST,NORDUFER 20,W-1000 BERLIN 65,GERMANY.
NR 5
TC 829
Z9 929
U1 2
U2 184
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 81
EP 82
DI 10.1038/351081a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300066
PM 1902911
DA 2026-03-10
ER

PT J
AU FALKNER, KK
   ONEILL, DJ
   TODD, JF
   MOORE, WS
   EDMOND, JM
AF FALKNER, KK
   ONEILL, DJ
   TODD, JF
   MOORE, WS
   EDMOND, JM
TI DEPLETION OF BARIUM AND RA-226 IN BLACK-SEA SURFACE WATERS OVER THE PAST 30 YEARS
SO NATURE
LA English
DT Article
ID river-winyah bay; particulate matter; ra-226; estuary; sediments; behavior; shelf; ocean; cycle; flux
AB THE nearly landlocked waters of the Black Sea support a valuable fishery, but are also particularly vulnerable to anthropogenic disturbance.  Here we use dissolved barium and radium-226 as tracers, to investigate the biogeochemical health of the sea.  Both elements are brought to surface waters by vertical mixing of deeper, enriched waters 1,2, and by rivers 3-8; these inputs should ordinarily be balanced by outflow of surface waters at the Bosporus, and by biologically mediated removal of Ra-226-bearing barite.  We show, however, that surface-water inventories have been substantially depleted over the past few decades:  recent (1988-89) barium concentrations were 1.6 times lower than in 1975 9; and recent Ra-226 concentrations were 3.5 times lower than in 1958 10 and 1967 11.  These observations suggest that steady-state cycling of these elements has been perturbed by increased primary productivity, presumably fuelled by nutrients from industry and agricultural runoff, and to a lesser extent by decreased fluvial sediment loads owing to extensive impoundment of rivers in the region.
C1 MIT,CAMBRIDGE,MA 02139.
   UNIV S CAROLINA,COLUMBIA,SC 29208.
C3 Massachusetts Institute of Technology (MIT); University of South Carolina System; University of South Carolina Columbia
NR 30
TC 34
Z9 35
U1 1
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 491
EP 494
DI 10.1038/350491a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300047
DA 2026-03-10
ER

PT J
AU SADEGHNASSERI, S
   GERMAIN, RN
AF SADEGHNASSERI, S
   GERMAIN, RN
TI A ROLE FOR PEPTIDE IN DETERMINING MHC CLASS-II STRUCTURE
SO NATURE
LA English
DT Article
ID major histocompatibility complex; separate alpha-chains; immunogenic peptides; antigenic peptides; lymphocyte-t; beta-chains; molecules; binding; ia; recognition
AB T LYMPHOCYTES recognize antigen-derived peptides associated with major histocompatibility complex (MHC) class I or class II proteins 1,2.  Peptide is critical in class I heavy folding and/or stable association with beta-2-Microglobulin 3-6.  Although data exist suggesting a relationship between class II structure and peptide association 7-9, no equivalent positive contribution of peptide to the folding state or stability of class II dimers has yet been demonstrated. We report here that most purified E-alpha(k)E-beta-k molecules leaving low pH in the absence of specific peptide lack a compact, stable dimeric structure. Brief exposure to the appropriate peptide just before and during neutralization promotes this specific conformation in proportion to stably bound peptide, indicating that peptide is important in determining class II MHC structure. Our results also indicate that efficient generation of long-lived peptide-class II complexes involves two stages:  initial peptide binding in an acidic environment, which enhances the ability of class II to enter a conformation, from which stabilization upon neutralization results in high-affinity binding of previously associated peptide.
RP SADEGHNASSERI, S (corresponding author), NIAID,IMMUNOL LAB,LYMPHOCYTE BIOL SECT,BETHESDA,MD 20892, USA.
NR 26
TC 292
Z9 308
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 167
EP 170
DI 10.1038/353167a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100054
PM 1653903
DA 2026-03-10
ER

PT J
AU CARRELL, RW
   EVANS, DL
   STEIN, PE
AF CARRELL, RW
   EVANS, DL
   STEIN, PE
TI MOBILE REACTIVE CENTER OF SERPINS AND THE CONTROL OF THROMBOSIS
SO NATURE
LA English
DT Article
ID crystal-structure; alpha-1-proteinase inhibitor; conformational change; ovalbumin; alpha-1-antitrypsin; absence; model
AB TWO protease inhibitors in human plasma play a key part in the control of thrombosis:  antithrombin inhibits coagulation and the plasminogen activator inhibitor PAI-1 inhibits fibrinolysis, the dissolving of clots.  Both inhibitors are members of the serpin family and both exist in the plasma in latent or inactive forms.  We show here that the reactive centre of the serpins can adopt varying conformations and that mobility of the reactive centre is necessary for the function of antithrombin and its binding and activation by heparin; the identification of a new locked conformation explains the latent inactive state of PAI-1.  This ability to vary conformation not only allows the modulation of inhibitory activity but also protects the circulating inhibitor against proteolytic attack.  Together these findings explain the retention by the serpins of a large and unconstrained reactive centre as compared to the small fixed peptide loop of other families of serine protease inhibitors.
RP CARRELL, RW (corresponding author), UNIV CAMBRIDGE,CTR MRC,DEPT HAEMATOL,HILLS RD,CAMBRIDGE CB2 2QH,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 21
TC 296
Z9 312
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 576
EP 578
DI 10.1038/353576a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300074
PM 1922367
DA 2026-03-10
ER

PT J
AU ALATALO, RV
   HOGLUND, J
   LUNDBERG, A
AF ALATALO, RV
   HOGLUND, J
   LUNDBERG, A
TI LEKKING IN THE BLACK GROUSE - A TEST OF MALE VIABILITY
SO NATURE
LA English
DT Article
ID mate choice; selection; fitness
AB LEKS, where males congregate to display and females attend only to mate, present one of the most remarkable outcomes of sexual selection 1.  It is a common but untested belief that females mate with the most vigorous males 2.  In leks of the black grouse Tetrao tetrix, males dominant in winter flocks were most successful in mating, as were males winning fights over female dummies placed at territory boundaries.  Males tear feathers from each others' tail ornaments in combats, and attractive males always had undamaged tails.  We report here that by choosing victorious males, females mate with males that are most likely to survive the following six months.  There is a strong association between female preference and male viability which supports a basic assumption of the 'good gene' models (refs. 3-9) where choosy females benefit through better viability of their offspring.  But females may also be choosing viable males for immediate benefits 2,10, in particular if diseases can be transmitted during copulations.
C1 UNIV UPPSALA,DEPT ZOOL,S-75122 UPPSALA,SWEDEN.
C3 Uppsala University
RP ALATALO, RV (corresponding author), UNIV JYVASKYLA,DEPT BIOL,YLIOPISTONKATU 9,SF-40100 JYVASKYLA,FINLAND.
NR 22
TC 144
Z9 152
U1 0
U2 60
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 155
EP 156
DI 10.1038/352155a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700056
DA 2026-03-10
ER

PT J
AU GUO, YJ
   KARASAWA, N
   GODDARD, WA III
AF GUO, YJ
   KARASAWA, N
   GODDARD, WA III
TI PREDICTION OF FULLERENE PACKING IN C60 AND C70 CRYSTALS
SO NATURE
LA English
DT Article
ID c-60; spectra; form
AB RECENT breakthroughs 1,2 in synthesizing large amounts of C60, C70 and other fullerenes 3 have made possible studies of the structures and properties of fullerene crystals. Using a force field developed recently for sp2 carbon atoms, we predict here the crystal structures and cohesive energies for close-packed crystals of C60 and C70. We predict, and confirm from calculations, that for C60 face-centered cubic (f.c.c.) packing is more stable than hexagonal close-packing (h.c.p.), by 0.90 kcal mol-1, whereas for C70 h.c.p. is more stable than f.c.c. by 0.35 kcal mol-1. The cubic structure of C60 undergoes an orthorhombic distortion to space group Cmca at 0 K. At higher temperatures there is rapid reorientation (but not free rotation) of C60 molecules, suggesting that above about 200 K a phase transition occurs to an orientationally disordered, f.c.c. structure (with a room-temperature lattice parameter of 14.13 angstrom). This may correspond to the first-order transition observed 4 at 249 K. The threefold axes of the C60 molecules in the low-temperature structure are not aligned with the threefold crystallographic axes.
RP GUO, YJ (corresponding author), CALTECH, ARTHUR AMOS NOYES LAB CHEM PHYS, BECKMAN INST 139-74, CTR MAT & MOLEC SIMULAT, PASADENA, CA 91125 USA.
NR 15
TC 334
Z9 358
U1 0
U2 95
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 464
EP 467
DI 
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800049
DA 2026-03-10
ER

PT J
AU KALLEN, J
   SPITZFADEN, C
   ZURINI, MGM
   WIDER, G
   WIDMER, H
   WUTHRICH, K
   WALKINSHAW, MD
AF KALLEN, J
   SPITZFADEN, C
   ZURINI, MGM
   WIDER, G
   WIDMER, H
   WUTHRICH, K
   WALKINSHAW, MD
TI STRUCTURE OF HUMAN CYCLOPHILIN AND ITS BINDING-SITE FOR CYCLOSPORINE-A DETERMINED BY X-RAY CRYSTALLOGRAPHY AND NMR-SPECTROSCOPY
SO NATURE
LA English
DT Article
ID cis-trans isomerase; protein; refinement
AB THE protein cyclophilin is the major intracellular receptor for the immunosuppressive drug cyclosporin A (ref. 1). Cyclosporin A acts as an inhibitor of T-cell activation and can prevent graft rejection in organ and bone marrow transplantation 2.  Cyclophilin may be responsible for mediating this immunosuppressive response. Cyclophilin also catalyses the interconversion of the cis and trans isomers of the peptidyl-prolyl amide bonds of peptide and protein substrates 3,4.  Here we report the X-ray crystal structure of human recombinant cyclophilin complexed with a tetrapeptide and the identification, by nuclear magnetic resonance spectroscopy, of the specific binding site for cyclosporin A. Cyclophilin has an eight-stranded antiparallel beta-barrel structure. The prolyl isomerase substrate-binding site is coincident with the cyclosporin-binding site. These results may help to provide a structural basis for rationalizing the immunosuppressive function of the cyclosporin-cyclophilin system and will also be important in the design of improved immunosuppressant drugs.
C1 SANDOZ PHARMA AG,PRECLIN RES,CH-4002 BASEL,SWITZERLAND.
   SWISS FED INST TECHNOL,INST MOLEK BIOL & BIOPHYS,CH-8093 ZURICH,SWITZERLAND.
C3 Novartis; Sandoz; Swiss Federal Institutes of Technology Domain; ETH Zurich
NR 22
TC 267
Z9 289
U1 0
U2 44
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 276
EP 279
DI 10.1038/353276a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400066
PM 1896075
DA 2026-03-10
ER

PT J
AU EGEBJERG, J
   BETTLER, B
   HERMANSBORGMEYER, I
   HEINEMANN, S
AF EGEBJERG, J
   BETTLER, B
   HERMANSBORGMEYER, I
   HEINEMANN, S
TI CLONING OF A CDNA FOR A GLUTAMATE RECEPTOR SUBUNIT ACTIVATED BY KAINATE BUT NOT AMPA
SO NATURE
LA English
DT Article
ID amino-acid receptors; functional expression; xenopus-oocytes; kainic acid; nervous-system; binding-sites; pharmacology; quisqualate; family; sequence
AB FAST excitatory transmission in the vertebrate central nervous system is mediated mainly by L-glutamate. On the basis of pharmacological, physiological and agonist binding properties, the ionotropic glutamate receptors are classified into NMDA (N-methyl-D-aspartate), AMPA (alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate) and kainate subtypes 1. Sequence homology between complementary DNA clones encoding non-NMDA glutamate receptor subunits reveals at least two subunit classes: the GluR1 to GluR4 class 2-6 and the GluR5 class 7. Here we report the cloning and expression of a functional rat glutamate receptor subunit cDNA, GluR6, which has a very different pharmacology from that of the GluR1-GluR4 class. Receptors generated from the GluR1-GluR4 class have a higher apparent affinity for AMPA than for kainate 3-6. When expressed in Xenopus oocytes the homomeric GluR6 receptor is activated by kainate, quisqualate and L-glutamate but not by AMPA, and the apparent affinity for kainate is higher than for receptors from the GluR1-GluR4 class. Desensitization of the receptor was observed with continuous application of agonist. The homomeric GluR6 glutamate receptor exhibits an outwardly rectifying current-voltage relationship. In situ hybridizations reveal a pattern of GluR6 gene expression reminiscent of the binding pattern obtained with [H-3]kainate.
RP EGEBJERG, J (corresponding author), SALK INST BIOL STUDIES, MOLEC NEUROBIOL LAB, LA JOLLA, CA 92037 USA.
NR 22
TC 589
Z9 636
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 745
EP 748
DI 10.1038/351745a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100064
PM 1648177
DA 2026-03-10
ER

PT J
AU BOCKELEEMORVAN, D
   COLOM, P
   CROVISIER, J
   DESPOIS, D
   PAUBERT, G
AF BOCKELEEMORVAN, D
   COLOM, P
   CROVISIER, J
   DESPOIS, D
   PAUBERT, G
TI MICROWAVE DETECTION OF HYDROGEN-SULFIDE AND METHANOL IN COMET AUSTIN (1989C1)
SO NATURE
LA English
DT Article
ID fluorescence; molecules; p/halley; spectrum
AB INFRARED and microwave spectroscopy can be used to identify and study the parent molecules directly sublimed from cometary nuclei.  Here we report spectroscopic observations of comet Austin (1989c1) at millimetre wavelengths using the 30-m telescope of the Institut de Radio Astronomie Millimetrique (IRAM).  We detected the rotational transitions of hydrogen cyanide and formaldehyde, which were previously observed in comets Halley and Brorsen-Metcalf 1.  In addition, we identified hydrogen sulphide and methanol, neither of which has previously been detected in a comet.  The presence of hydrogen sulphide provides severe constraints on the formation of cometary nuclei, whereas that of methanol supports the hypothesis that cometary nuclei have retained, at least in part, some primitive material originating from the solar nebula.
C1 CTR ASTRON YEBES,E-19080 GUADALAJARA,SPAIN.
   INST RADIO ASTRON MILLIMETR,E-18012 GRANADA,SPAIN.
   OBSERV BORDEAUX,F-33270 FLOIRAC,FRANCE.
C3 Universite de Bordeaux
RP BOCKELEEMORVAN, D (corresponding author), OBSERV PARIS SECT,F-92195 MEUDON,FRANCE.
NR 19
TC 82
Z9 84
U1 1
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 318
EP 320
DI 10.1038/350318a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800083
DA 2026-03-10
ER

PT J
AU SIGURDSSON, H
   BONTE, P
   TURPIN, L
   CHAUSSIDON, M
   METRICH, N
   STEINBERG, M
   PRADEL, P
   DHONDT, S
AF SIGURDSSON, H
   BONTE, P
   TURPIN, L
   CHAUSSIDON, M
   METRICH, N
   STEINBERG, M
   PRADEL, P
   DHONDT, S
TI GEOCHEMICAL CONSTRAINTS ON SOURCE REGION OF CRETACEOUS TERTIARY IMPACT GLASSES
SO NATURE
LA English
DT Article
ID systematics; isotopes; history; sulfur; marine; mexico
AB THE 50-cm-thick Cretaceous/Tertiary boundary layer at Beloc in Haiti contains spherules of silicic black glass, 1-8 mm in diameter, which have been attributed to impact fusion of continental crust 1. Calcic yellow glass (up to 30 wt% CaO) forms a coating on and streaks within some black glass spherules, and has been attributed to melting of carbonate-rich sediment 1, or organic-rich or pyritic limestone 2.  Here we present new trace-element and stable and radiogenic isotope data which show that the silicic glass is derived from continental crust of andesitic composition, whereas the high-Ca glass formed by melting of evaporite-rich sediment. This is confirmed by melting experiments with evaporite and andesite at 1,200-1,400-degrees-C, which approximately reproduce the high-Ca glass. The temperature-dependent variation of sulphur content in synthetic high-Ca glasses indicates a formation temperature of 1,300-degrees-C for the Haiti glasses. The geology of the impact site inferred from the geochemistry of the Haiti glasses matches the lithologies found in the 180-km Chicxulub structure, which occurs in Cretaceous evaporite deposits in Mexico. The high sulphur content of the calcic glasses suggests that the impact may have generated significant emissions of sulphur dioxide to the atmosphere, causing short-term global cooling.
C1 UNIV ORSAY,GEOCHIM SEDIMENTOL LAB,F-91405 ORSAY,FRANCE.
   UNIV RHODE ISL,GRAD SCH OCEANOG,NARRAGANSETT,RI 02882.
   CEA,CTR VALLEE RHONE,F-30205 BAGNOLS SUR CEZE,FRANCE.
   CENS,LAB PIERRE SUE,F-91191 GIF SUR YVETTE,FRANCE.
   CTR RECH PETROG & GEOCHIM,CNRS,F-54501 VANDOEUVRE NANCY,FRANCE.
C3 Universite Paris Saclay; University of Rhode Island; CEA; CEA; Universite Paris Saclay; Universite de Lorraine; Centre National de la Recherche Scientifique (CNRS)
RP SIGURDSSON, H (corresponding author), CEA,CNRS,CTR FAIBLES RADIOACT,F-91198 GIF SUR YVETTE,FRANCE.
NR 33
TC 79
Z9 83
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 839
EP 842
DI 10.1038/353839a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200057
DA 2026-03-10
ER

PT J
AU SNOW, E
   KIDMAN, S
AF SNOW, E
   KIDMAN, S
TI EFFECT OF FLUORINE ON SOLID-STATE ALKALI INTERDIFFUSION RATES IN FELDSPAR
SO NATURE
LA English
DT Article
ID chemical diffusion; na
AB SOLID-STATE diffusion plays an important part in controlling the chemical and physical nature of minerals and rocks, and the mechanism and kinetics of diffusion are in turn affected by the physical and chemical environment.  We have investigated the effects of fluorine on alkali interdiffusion in feldspars because it is known that fluorine strongly affects the structure and viscosity of melt 1, fluid-melt partition coefficients 2, mineral melting temperatures 3,4 and, most significantly, the rate of cation diffusion in melts.  We report the results of diffusion-couple experiments run at 600-800-degrees-C and 200 MPa for 2-24 days.  At relatively low fluorine fugacities the alkali interdiffusion rate was increased by about four orders of magnitude compared with the fluorine-absent system, and the activation energy was decreased.  The magnitude of the effect is great enough to explain unexpectedly large exsolution lamellae in some rhyolites, and also calls into question the effects of fluorine on other solid-state reactions involving diffusion.  Because fluorine is a common volatile component in lgneous and metamorphic rocks, the implications of our results may extend far beyond this simple example.
RP SNOW, E (corresponding author), UNIV ARIZONA,DEPT GEOSCI,GOULD SIMPSON BLDG,TUCSON,AZ 85721, USA.
NR 13
TC 22
Z9 24
U1 1
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 231
EP 233
DI 10.1038/349231a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900052
DA 2026-03-10
ER

PT J
AU KAWAKATSU, H
AF KAWAKATSU, H
TI INSIGNIFICANT ISOTROPIC COMPONENT IN THE MOMENT TENSOR OF DEEP EARTHQUAKES
SO NATURE
LA English
DT Article
ID seismic moment; colombian earthquake; focus earthquakes; july 31; mechanism; parameters; retrieval; waves
AB THE mechanism responsible for deep-focus earthquakes, which occur at depths of 300-700 km in subducting slabs, has been a long-standing problem in geophysics. Unlike shallow earthquakes, deep earthquakes cannot be attributed to frictional instabilities across a fault plane, because of high frictional resistance to sliding at depth. A volumetric change associated with a phase transition, expected to occur at depth 1-3, is often invoked as the physical mechanism; if so, the resulting source mechanism should contain a major isotropic component. Although many researchers have attempted to observe such an isotropic component 4-10, no one has yet convincingly proved or disproved its presence. There exists a portion of the seismogram which is well suited to resolve the isotropic component of deep earthquakes but which has not been analysed by previous workers. Here I use this component in a systematic analysis of 19 large deep earthquakes, and show that no significant isotropic component (< 10% of the seismic moment) exists. A sudden implosive phase change can thus be ruled out as the primary physical mechanism for deep earthquakes.
RP KAWAKATSU, H (corresponding author), GEOL SURVEY JAPAN, 1-1-3 HIGASHI, TSUKUBA, IBARAKI 305, JAPAN.
NR 23
TC 59
Z9 70
U1 0
U2 5
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 50
EP 53
DI 10.1038/351050a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300055
DA 2026-03-10
ER

PT J
AU LIVERMORE, RA
   TOMLINSON, JS
   WOOLLETT, RW
AF LIVERMORE, RA
   TOMLINSON, JS
   WOOLLETT, RW
TI UNUSUAL SEA-FLOOR FABRIC NEAR THE BULLARD FRACTURE-ZONE IMAGED BY GLORIA SIDESCAN SONAR
SO NATURE
LA English
DT Article
ID ridge-transform intersection; troodos ophiolite; triple junction; plate boundary; fault zone; tectonics; lithosphere; kinematics; rotations; cyprus
AB THE tectonic fabric of the sea floor created at spreading ridges generally curves in the direction of ridge offset near transform faults, owing to the influence of shearing stress on transform faults. Here we present new GLORIA sidescan sonar images from the South American-Antarctic Ridge, showing fabric to the north of the Bullard transform with a reversed sense of curvature. This curvature, and that observed in an area of older sea floor near the eastern ridge-transform intersection, appears to result from post-emplacement emplacement deformation, caused by the transmission of shear stresses across transforms. The deformation was probably related to a major Early Miocene change in spreading direction, which would have imposed a component of compression on the transforms. Such a sense of curvature has not, to our knowledge, been observed elsewhere on the deep ocean floor, although apparently similar patterns have been reported in ophiolites.
RP LIVERMORE, RA (corresponding author), BRITISH ANTARCTIC SURVEY,NERC,HIGH CROSS,MADINGLEY RD,CAMBRIDGE CB3 0ET,ENGLAND.
NR 32
TC 15
Z9 17
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 158
EP 161
DI 10.1038/353158a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100051
DA 2026-03-10
ER

PT J
AU HOWARD, JB
   MCKINNON, JT
   MAKAROVSKY, Y
   LAFLEUR, AL
   JOHNSON, ME
AF HOWARD, JB
   MCKINNON, JT
   MAKAROVSKY, Y
   LAFLEUR, AL
   JOHNSON, ME
TI FULLERENES C60 AND C70 IN FLAMES
SO NATURE
LA English
DT Article
ID polycyclic aromatic-hydrocarbons; performance liquid-chromatography; carbon; c-60; soot; buckminsterfullerene; form
AB THE fullerenes C60 and C70 were first identified 1 in carbon vapour produced by laser irradiation of graphite, and have recently been produced in macroscopic quantities 2-5 by vaporization of graphite with resistive heating.  It has also been suggested 6-9 that fullerenes might be formed in sooting flames, and indeed all-carbon ions with mass/charge ratios suggestive of fullerenes have been detected in flames 10-12.  These species were assumed to have the cage structures of fullerenes, but the mass spectroscopic evidence could not establish this conclusively.  We have now collected samples of condensible compounds and soot from hydrocarbon combustion under a range of conditions, and analysed these using conventional techniques in an effort to detect fullerenes.  Spectroscopic studies reveal the presence of C60 and C70 in yields and ratios that depend on temperature, pressure, carbon/oxygen ratio and residence time in the flame.  Control of these conditions allows optimal yields of 3 g of fullerenes per kilogram of fuel carbon burned, and variation of the C70/C60 ratio over the range 0.26-5.7.
C1 MIT,CTR ENVIRONM HLTH SCI,CAMBRIDGE,MA 02139.
C3 Massachusetts Institute of Technology (MIT)
RP HOWARD, JB (corresponding author), MIT,DEPT CHEM ENGN,CAMBRIDGE,MA 02139, USA.
NR 27
TC 490
Z9 556
U1 5
U2 156
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 139
EP 141
DI 10.1038/352139a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700049
PM 2067575
DA 2026-03-10
ER

PT J
AU CHRISTINCK, ER
   LUSCHER, MA
   BARBER, BH
   WILLIAMS, DB
AF CHRISTINCK, ER
   LUSCHER, MA
   BARBER, BH
   WILLIAMS, DB
TI PEPTIDE BINDING TO CLASS-I MHC ON LIVING CELLS AND QUANTITATION OF COMPLEXES REQUIRED FOR CTL LYSIS
SO NATURE
LA English
DT Article
ID monoclonal-antibody; hla molecules; recognition; antigens; beta-2-microglobulin; invitro; h-2
AB ANTIGENIC peptides are presented to CD8+ T lymphocytes by class I major histocompatibility complex (MHC) molecules 1,2. Peptides specifically bind to purified class I molecules in vitro 3-7, and to class I molecules on cells at nonphysiological temperatures 8. We report here the kinetic and equilibrium parameters for the binding of radiolabelled influenza nucleoprotein peptides (NP-Y365-380 and shorter homologues) to the murine H-2D(b) molecule on intact, viable cells at 37-degrees-C. In contrast to earlier reports, we show that peptide binding is rapid and reversible, with dissociation constants ranging from nanomolar to micromolar, suggestive of typical ligand-receptor interactions. Only 10% of cell-surface D(b) molecules can bind these peptides. To address the relationship between peptide binding and T-cell recognition of the antigen-MHC complex, we determined the minimum number of complexes required to sensitize a target cell for lysis by class I-restricted cytotoxic T-lymphocytes. Our data indicate that EL4 thymoma cells (H-2b) can be sensitized for lysis by cytotoxic T-lymphocytes when as few as 200 class I-peptide complexes (less than 0.08% of surface D(b) molecules) are present per cell.
C1 UNIV TORONTO,DEPT IMMUNOL,TORONTO M5S 1A8,ONTARIO,CANADA.
C3 University of Toronto
RP CHRISTINCK, ER (corresponding author), UNIV TORONTO,DEPT BIOCHEM,TORONTO M5S 1A8,ONTARIO,CANADA.
NR 29
TC 343
Z9 372
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 67
EP 70
DI 10.1038/352067a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800072
PM 2062379
DA 2026-03-10
ER

PT J
AU CHEN, JH
   SEEMAN, NC
AF CHEN, JH
   SEEMAN, NC
TI SYNTHESIS FROM DNA OF A MOLECULE WITH THE CONNECTIVITY OF A CUBE
SO NATURE
LA English
DT Article
ID nucleic-acid junctions; design
AB A PRINCIPAL goal of biotechnology is the assembly of novel biomaterials for analytical, industrial and therapeutic purposes.  The advent of stable immobile nucleic acid branched junctions 1-4 makes DNA a good candidate for building frameworks to which proteins or other functional molecules can be attached and thereby juxtaposed 5-7.  The addition of single-stranded 'sticky' ends 8 to branched DNA molecules converts them into macromolecular valence clusters that can be ligated together 1.  The edges of these frameworks are double-helical DNA, and the vertices correspond to the branch points of junctions.  Here, we report the construction from DNA of a covalently closed cube-like molecular complex containing twelve equal-length double-helical edges arranged about eight vertices.  Each of the six 'faces' of the object is a single-stranded cyclic molecule, doubly catenated to four neighbouring strands, and each vertex is connected by an edge to three others.  Each edge contains a unique restriction site for analytical purposes.  This is the first construction of a closed polyhedral object from DNA.
RP CHEN, JH (corresponding author), NYU,DEPT CHEM,NEW YORK,NY 10003, USA.
NR 15
TC 1149
Z9 1487
U1 10
U2 437
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 631
EP 633
DI 10.1038/350631a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200067
PM 2017259
DA 2026-03-10
ER

PT J
AU GEHRING, CA
   WHITHAM, TG
AF GEHRING, CA
   WHITHAM, TG
TI HERBIVORE-DRIVEN MYCORRHIZAL MUTUALISM IN INSECT-SUSCEPTIBLE PINYON PINE
SO NATURE
LA English
DT Article
ID growth; colonization; leaves; fungi
AB THE mutualistic ectomycorrhizal fungi associated with the roots of woody perennials can enhance nutrient uptake and provide protection from pathogens in exchange for up to 40% of the photosynthate produced by host plants 1-9.  By removing photosynthetic tissue, herbivores could reduce the amount of photosynthate available for maintaining this mutualism 10-15,29.  Here we examine how ectomycorrhizal levels vary between trees resistant and susceptible to an insect herbivore, and demonstrate how mycorrhizal levels respond to the experimental removal of a native herbivore under natural conditions.  We find that pinyon pine trees susceptible to chronic insect attack have 33% fewer ectomycorrhizae than resistant trees, demonstrating that the herbivore-mycorrhizae-host plant interaction differs between resistant and susceptible trees.  We removed insects from susceptible trees and find that the mycorrhizal levels of these trees increased to a level comparable to that of resistant trees. This demonstrates that herbivores negatively affect the mutualism between ectomycorrhizal fungi and susceptible trees, and that mycorrhizal levels can rebound after herbivore removal.  The dynamics of these interactions on resistant and susceptible plants could be important for understanding plant-pest interactions in natural and managed systems.
RP GEHRING, CA (corresponding author), NO ARIZONA UNIV,DEPT BIOL SCI,FLAGSTAFF,AZ 86011, USA.
NR 29
TC 114
Z9 125
U1 1
U2 40
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 556
EP 557
DI 10.1038/353556a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300066
DA 2026-03-10
ER

PT J
AU KLEUSS, C
   HESCHELER, J
   EWEL, C
   ROSENTHAL, W
   SCHULTZ, G
   WITTIG, B
AF KLEUSS, C
   HESCHELER, J
   EWEL, C
   ROSENTHAL, W
   SCHULTZ, G
   WITTIG, B
TI ASSIGNMENT OF G-PROTEIN SUBTYPES TO SPECIFIC RECEPTORS INDUCING INHIBITION OF CALCIUM CURRENTS
SO NATURE
LA English
DT Article
ID gtp-binding-protein; pituitary cell-line; anti-sense rna; messenger-rna; alpha-subunit; molecular-cloning; genetic-analysis; 2 forms; antisense; channels
AB The inhibition of voltage-dependent Ca2+ channels in secretory cells by plasma membrane receptors is mediated by pertussis toxin-sensitive G proteins. Multiple forms of G proteins have been described, differing principally in their alpha-subunits, but it has not been possible to establish which G-protein subtype mediates inhibition by a specific receptor. By intranuclear injection of antisense oligonucleotides into rat pituitary GH3 cells, the essential role of the G(o)-type G proteins in Ca2+-channel inhibition is established: the subtypes G(o1) and G(o2) mediate inhibition through the muscarinic and somatostatin receptors, respectively.
C1 FREE UNIV BERLIN, INST PHARMAKOL, W-1000 BERLIN 33, GERMANY.
C3 Free University of Berlin
RP KLEUSS, C (corresponding author), FREE UNIV BERLIN, INST MOLEK BIOL & BIOCHEM, ARNIMALLEE 22, W-1000 BERLIN 33, GERMANY.
NR 47
TC 566
Z9 578
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 43
EP 48
DI 10.1038/353043a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500050
PM 1679199
DA 2026-03-10
ER

PT J
AU DAVID, WIF
   IBBERSON, RM
   MATTHEWMAN, JC
   PRASSIDES, K
   DENNIS, TJS
   HARE, JP
   KROTO, HW
   TAYLOR, R
   WALTON, DRM
AF DAVID, WIF
   IBBERSON, RM
   MATTHEWMAN, JC
   PRASSIDES, K
   DENNIS, TJS
   HARE, JP
   KROTO, HW
   TAYLOR, R
   WALTON, DRM
TI CRYSTAL-STRUCTURE AND BONDING OF ORDERED C60
SO NATURE
LA English
DT Article
AB STRUCTURAL studies 1-3 of crystalline C60 (ref. 4) have indicated that at room temperature the C60 molecules are orientationally disordered and the crystal structure may be regarded as a face-centred cubic configuration of C60 spheres. Below 249 K, however, the molecules become orientationally ordered 3 and a simple cubic lattice results, corresponding to a symmetry change from Fm3BAR to Pa3BAR. Here we present the results of a neutron powder diffraction study of the low-temperature ordered structure, which reveals the packing configuration of the C60 molecules. The C60 units are rotated in an anticlockwise manner around the [111] direction by approximately 98-degrees from the ideal Fm3BAR configuration. This apparently arbitrary rotation in fact results from an optimized ordering scheme in which electron-rich short (1.391-angstrom) inter-pentagon bonds face the electron-poor pentagon centres of adjacent C60 units. The high symmetry of the C60 molecule allows these interactions to be optimized identically for all twelve nearest neighbours, a possibility that is by no means intuitively obvious. The bonds common to a given pentagon are somewhat longer (1.455 angstrom). The high degree of bonding optimization and the absence of bonding frustration accounts for the high ordering temperature of 249 K (ref. 5).
C1 UNIV SUSSEX,SCH CHEM & MOLEC SCI,BRIGHTON BN1 9QJ,E SUSSEX,ENGLAND.
C3 University of Sussex
RP DAVID, WIF (corresponding author), RUTHERFORD APPLETON LAB,DIV ISIS SCI,DIDCOT OX11 0QX,OXON,ENGLAND.
NR 11
TC 966
Z9 1027
U1 4
U2 218
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 147
EP 149
DI 10.1038/353147a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100047
DA 2026-03-10
ER

PT J
AU SCHMITT, JHMM
   SNOWDEN, SL
   ASCHENBACH, B
   HASINGER, G
   PFEFFERMANN, E
   PREDEHL, P
   TRUMPER, J
AF SCHMITT, JHMM
   SNOWDEN, SL
   ASCHENBACH, B
   HASINGER, G
   PFEFFERMANN, E
   PREDEHL, P
   TRUMPER, J
TI A SOFT-X-RAY IMAGE OF THE MOON
SO NATURE
LA English
DT Article
AB A soft X-ray image of the Moon obtained by the Rontgen Observatory Satellite ROSAT clearly shows a sunlit crescent, demonstrating that the Moon's X-ray luminosity arises from backscattering of solar X-rays.  The Moon's optically dark side is also X-ray dark, and casts a distinct shadow on the diffuse cosmic X-ray background.  Unexpectedly, the dark side seems to emit X-rays at a level about one per cent of that of the bright side; this emission very probably results from energetic solar-wind electrons striking the Moon's surface.
C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706.
C3 University of Wisconsin System; University of Wisconsin Madison
RP SCHMITT, JHMM (corresponding author), MAX PLANCK INST PHYS & ASTROPHYS,INST EXTRATERR PHYS,KARL SCHWARZSCHILD STR 1,W-8046 GARCHING,GERMANY.
NR 12
TC 62
Z9 68
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 583
EP 587
DI 10.1038/349583a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000050
DA 2026-03-10
ER

PT J
AU RAWLINGS, S
   SAUNDERS, R
AF RAWLINGS, S
   SAUNDERS, R
TI EVIDENCE FOR A COMMON CENTRAL-ENGINE MECHANISM IN ALL EXTRAGALACTIC RADIO-SOURCES
SO NATURE
LA English
DT Article
ID frii radiogalaxy; galaxy; spectrophotometry; dynamics; quasars; sample; jet; gas
AB Extragalactic radio sources produce radio waves and narrow emission lines by very different physical processes:  synchrotron radio emission arises from lobes filled with magnetized plasma extending over scales of kiloparsecs to megaparsecs, fed by the total kinetic power, Q, of jets driven by a central engine, whereas narrow-line luminosity L(NLR) arises from gas, typically concentrated in the inner few kiloparsecs, that has been photoionized by a nuclear source.  We report here the discovery of a close relationship between Q and L(NLR) - an approximate proportionality which extends over four orders of magnitude from low-Q radio sources with relaxed structures to high-Q, radio-luminous classical double-lobe radio galaxies.  Objects with broad Balmer lines follow the same trend as those without, showing that quasar-like photoionizing sources are ubiquitous but not always obvious.  Moreover, all radio-source central engines channel at least as much power into the jets as is radiated by accretion:  this high efficiency implies that the engine is a massive spinning black hole which both powers the jets and controls the accretion rate.
RP RAWLINGS, S (corresponding author), UNIV CAMBRIDGE,CAVENDISH LAB,MULLARD RADIO ASTRON OBSERV,MADINGLEY RD,CAMBRIDGE CB3 0HE,ENGLAND.
NR 30
TC 586
Z9 603
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 138
EP 140
DI 10.1038/349138a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800050
DA 2026-03-10
ER

PT J
AU BASHIR, ZI
   ALFORD, S
   DAVIES, SN
   RANDALL, AD
   COLLINGRIDGE, GL
AF BASHIR, ZI
   ALFORD, S
   DAVIES, SN
   RANDALL, AD
   COLLINGRIDGE, GL
TI LONG-TERM POTENTIATION OF NMDA RECEPTOR-MEDIATED SYNAPTIC TRANSMISSION IN THE HIPPOCAMPUS
SO NATURE
LA English
DT Article
ID collateral-commissural pathway; d-aspartate receptors; mouse central neurons; spinal-cord neurons; rat hippocampus; activation; antagonists; expression; induction; responses
AB Neurotransmission at most excitatory synapses in the brain operates through two types of glutamate receptor termed alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA) receptors; these mediate the fast and slow components of excitatory postsynaptic potentials respectively 1-3. Activation of NMDA receptors can also lead to a long-lasting modification in synaptic efficiency at glutamatergic synapses; this is exemplified in the CAl region of the hippocampus, where NMDA receptors mediate the induction of long-term potentiation (LTP) 4. It is believed that in this region LTP is maintained by a specific increase in the AMPA receptor-mediated synaptic response can undergo robust, synapse-specific LTP. This findings has implications for neuropathologies such as epilepsy and neurodegeneration, in which excessive NMDA receptor activation has been implicated 7. It adds fundamentally to theories of synaptic plasticity because NMDA receptor activation may, in addition to causing increased synaptic efficiency, directly alter the plasticity of synapses.
C1 UNIV BRISTOL, SCH MED SCI, DEPT PHARMACOL, BRISTOL BS8 1TD, AVON, ENGLAND.
   UNIV BIRMINGHAM, SCH MED, DEPT PHARMACOL, BIRMINGHAM B15 2TT, W MIDLANDS, ENGLAND.
   UNIV BRISTOL, SCH MED SCI, DEPT BIOCHEM, BRISTOL BS8 1TD, AVON, ENGLAND.
C3 University of Bristol; University of Birmingham; University of Bristol
FU Wellcome Trust Funding Source: Medline
NR 31
TC 338
Z9 373
U1 0
U2 25
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 156
EP 158
DI 10.1038/349156a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800058
PM 1846031
DA 2026-03-10
ER

PT J
AU FLYNN, GC
   POHL, J
   FLOCCO, MT
   ROTHMAN, JE
AF FLYNN, GC
   POHL, J
   FLOCCO, MT
   ROTHMAN, JE
TI PEPTIDE-BINDING SPECIFICITY OF THE MOLECULAR CHAPERONE BIP
SO NATURE
LA English
DT Article
ID newly synthesized proteins; heat-shock; cells; hydrophobicity; translocation; degradation; catalysts; core; atp
AB Members of the heat-shock protein family (hsp70s) can distinguish folded from unfolded proteins. This property is crucial to the role of hsp70s as molecular chaperones and is attributable to the amino-acid specificity of the peptide-binding site. The specificity for peptide ligands is investigated using a set of peptides of random sequence but defined chain length. The peptide-binding site selects for aliphatic residues and accommodates them in an environment energetically equivalent to the interior of a folded protein.
C1 EMORY UNIV, SCH MED, MICROCHEM FACIL, ATLANTA, GA 30322 USA.
   PRINCETON UNIV, DEPT MOLEC BIOL, MICROCHEM CORE FACIL, PRINCETON, NJ 08544 USA.
C3 Emory University; Princeton University
RP FLYNN, GC (corresponding author), SLOAN KETTERING MEM CANC CTR, ROCKEFELLER RES LAB, PROGRAM CELLULAR BIOCHEM & BIOPHYS, NEW YORK, NY 10021 USA.
NR 35
TC 695
Z9 777
U1 0
U2 36
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 726
EP 730
DI 10.1038/353726a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600057
PM 1834945
DA 2026-03-10
ER

PT J
AU KAPLAN, DR
   MARTINZANCA, D
   PARADA, LF
AF KAPLAN, DR
   MARTINZANCA, D
   PARADA, LF
TI TYROSINE PHOSPHORYLATION AND TYROSINE KINASE-ACTIVITY OF THE TRK PROTOONCOGENE PRODUCT INDUCED BY NGF
SO NATURE
LA English
DT Article
ID nerve growth-factor; pheochromocytoma cell line; acetylcholine; activation; increase; receptor
AB NERVE growth factor (NGF) is a neurotrophic factor responsible for the differentiation and survival of sympathetic and sensory neurons as well as selective populations of cholinergic neurons 1,2.  NGF binds to specific cell-surface receptors but the mechanism for transduction of the neurotrophic signal is unknown.  Several experiments using the NGF-responsive pheochromocytoma cell line, PC12, have implicated tyrosine phosphorylation in NGF-mediated responses, although no NGF-specific tyrosine kinases have been identified 3.  Here we show that NGF induces tyrosine phosphorylation and tyrosine kinase activity of the trk proto-oncogene product, a tyrosine kinase receptor whose expression is restricted in vivo to neurons of the sensory spinal and cranial ganglia of neural crest origin 4.  Tyrosine phosphorylation of trk by NGF is rapid, specific and occurs with picomolar quantities of factor, indicating that the response is mediated by physiological amounts of NGF.  Activation of the trk tyrosine kinase receptor provides a possible mechanism for signal transduction by NGF.
C1 NCI,FREDERICK CANC RES & DEV CTR,ABL BASIC RES PROGRAM,BETHESDA,MD 20892.
C3 Science Applications International Corporation (SAIC); SAIC-Frederick; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI)
RP KAPLAN, DR (corresponding author), NCI,FREDERICK CANC RES & DEV CTR,EUKARYOT SIGNAL TRANSDUCT GRP,POB B,BETHESDA,MD 20892, USA.
NR 21
TC 988
Z9 1073
U1 0
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 158
EP 160
DI 10.1038/350158a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500060
PM 1706478
DA 2026-03-10
ER

PT J
AU HU, PJ
   KING, DA
AF HU, PJ
   KING, DA
TI HOLOGRAPHIC IMAGES OF IODINE ATOMS ON A SILVER SURFACE FROM ELECTRON-EMISSION PATTERNS
SO NATURE
LA English
DT Article
ID photoelectron diffraction; spectroscopy; resolution; leed; pt(111); ag(111)
AB BARTON 1 has suggested that photoelectron interference patterns may be used directly as holograms to obtain atomic-resolution images of surface structures. Bulk structures have been obtained previously by this means from experimental patterns of high-energy Kikuchi(quasi-elastically scattered) and Auger electrons 2,3. Here we test the feasibility of this technique for determination of surface structures using Auger intensity patterns obtained 4,5 from iodine chemisorbed on a pseudomorphic silver monolayer on Pt{111}. By direct numerical holographic inversion, we obtain three-dimensional images which show that iodine adatoms are located in hollows of 3-fold symmetry on the surface. The images yield the site symmetry with good atomic resolution in the surface plane, but suffer from poor resolution along the Ag-I axis. We anticipate that data with better angular resolution obtained at low temperatures would improve the spatial resolution of such images.
RP HU, PJ (corresponding author), UNIV CAMBRIDGE,DEPT CHEM,CAMBRIDGE CB2 1EW,ENGLAND.
NR 24
TC 29
Z9 29
U1 2
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 831
EP 833
DI 10.1038/353831a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200054
DA 2026-03-10
ER

PT J
AU VORTKAMP, A
   GESSLER, M
   GRZESCHIK, KH
AF VORTKAMP, A
   GESSLER, M
   GRZESCHIK, KH
TI GLI3 ZINC-FINGER GENE INTERRUPTED BY TRANSLOCATIONS IN GREIG SYNDROME FAMILIES
SO NATURE
LA English
DT Article
ID cephalopolysyndactyly syndrome; localization; chromosome-7
AB THE Greig cephalopolysyndactyly syndrome (GCPS) is an autosomal dominant disorder affecting limb and craniofacial development in humans 1,2. GCPS-affected individuals are characterized by postaxial polysyndactyly of hands, preaxial polysyndactyly of feet, macroephaly, a broad base of the nose with mild hypertelorism and a prominent forehead. The genetic locus has been pinpointed to chromosome 7p13 by three balanced translocations associated with GCPS in different families 3,4,19.  This assignment is corroborated by the detection of two sporadic GCPS cases carrying overlapping deletions in 7p13 (ref. 7), as well as by tight linkage of GCPS to the epidermal growth factor receptor gene in 7p12-13 (ref. 8). Of the genes that map to this region, those encoding T cell receptor-gamma, interferon-beta-2, epidermal growth factor receptor, and Hox1.4, a potential candidate gene for GCPS, have been excluded from the region in which the deletions overlap 7,9.  Here we show that two of the three translocations interrupt the GLI3 gene, a zinc-finger gene of the GLI-Kruppel family already localized to 7p13 (refs 5, 6). The breakpoints are within the first third of the coding sequence. In the third translocation, chromosome 7 is broken at about 10 kilobases downstream of the 3' end of GLI3. Our results indicate that mutations disturbing normal GLI3 expression may have a causative role in GCPS.
RP VORTKAMP, A (corresponding author), UNIV MARBURG,INST HUMANGENET,BAHNHOFSTR 7A,W-3550 MARBURG,GERMANY.
NR 19
TC 477
Z9 525
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 539
EP 540
DI 10.1038/352539a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600066
PM 1650914
DA 2026-03-10
ER

PT J
AU NEJOH, H
AF NEJOH, H
TI INCREMENTAL CHARGING OF A MOLECULE AT ROOM-TEMPERATURE USING THE SCANNING TUNNELING MICROSCOPE
SO NATURE
LA English
DT Article
ID coulomb blockade; junctions
AB ADDING electrons to, or extracting them from, a sample of microscopic dimensions is opposed by a charging energy that depends on the object's capacitance. The stepwise charging ('Coulomb staircase') that is expected as a result has been observed for metal films and droplets, using the scanning tunnelling microscope (STM) to inject the charge 1-3.  But because of the very small charging energy, the effect was observable only at very low temperatures (approximately 4 K). Here I present evidence for incremental charging of a single molecule (a liquid crystal) from STM studies conducted at room temperature. I observe quasiperiodic variations in the current-voltage curve which I attribute to discrete changes in the molecule's charge. The width of the steps and the asymmetry between positive and negative bias, however, remain to be explained.
RP NEJOH, H (corresponding author), JRDC,ERATO,AONO ATOMCRAFT PROJECT,5-9-9 TOHKOHDAI,TSUKUBA,IBARAKI 30026,JAPAN.
NR 10
TC 42
Z9 44
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 640
EP 642
DI 10.1038/353640a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200062
DA 2026-03-10
ER

PT J
AU GAST, AP
   MONOVOUKAS, Y
AF GAST, AP
   MONOVOUKAS, Y
TI A NEW GROWTH INSTABILITY IN COLLOIDAL CRYSTALLIZATION
SO NATURE
LA English
DT Article
ID suspensions; transition
AB SUSPENSIONS of monodisperse colloidal particles are useful model systems for studying order-disorder transitions.  The bright iridescence of colloidal crystals, resulting from diffraction of visible light, is well-known 1-5.  We have shown recently that this diffraction process depolarizes light sufficiently to reveal the orientation of the primary diffraction planes through the colours observed in a polarizing microscope 6,7.  In the course of these investigations we have observed a new crystallization instability that can be explained, in part, by a diffusion-limited crystallization process.  Although it is analogous to the mechanism of pattern formation in molecular systems, here the instability occurs for particles interacting solely by repulsive forces.  We provide a qualitative explanation of the process using a classic Mullins-Sekerka 8 stability analysis.  Our observations suggest that colloidal suspensions can provide a useful model not only for the study of crystallization thermodynamics but also for investigations of ordering dynamics.
RP GAST, AP (corresponding author), STANFORD UNIV,DEPT CHEM ENGN,STANFORD,CA 94305, USA.
NR 15
TC 53
Z9 59
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 553
EP 555
DI 10.1038/351553a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400053
DA 2026-03-10
ER

PT J
AU VONAHSEN, U
   DAVIES, J
   SCHROEDER, R
AF VONAHSEN, U
   DAVIES, J
   SCHROEDER, R
TI ANTIBIOTIC INHIBITION OF GROUP-I RIBOZYME FUNCTION
SO NATURE
LA English
DT Article
ID catalytic core; ribosomal-rna; binding-site; introns; bacteriophage-t4; sequence; protein
AB THE discovery of catalytically active RNA has provided the basis for the evolutionary concept of an RNA world.  It has been proposed that during evolution the functions of ancient catalytic RNA were modulated by low molecular weight effectors, related to antibiotics, present in the primordial soup.   Antibiotics and RNA may have coevolved in the formation of the modern ribosome 1.  Here we report that a set of aminoglycoside antibiotics, which are known to interact with the decoding region of the 16S ribosomal RNA of Escherichia coli 2-4, inhibit the second step of splicing of the T4 phage-derived td intron.  Thus catalytic RNA seems to interact not only with a mononucleotide 5 and an amino acid 6, but also with another class of biomolecules, the sugars.  Splicing of other group I introns but not group II introns was inhibited.  The similarity in affinity and specificity of these antibiotics for group I introns and rRNAs may result from recognition of evolutionarily conserved structures.
C1 INST PASTEUR,UNITE GENIE MICROBIOL,F-75724 PARIS 15,FRANCE.
C3 Pasteur Network; Universite Paris Cite; Institut Pasteur Paris
RP VONAHSEN, U (corresponding author), UNIV VIENNA,INST MIKROBIOL & GENET,ALTHANSTR 14,A-1090 VIENNA,AUSTRIA.
NR 23
TC 238
Z9 275
U1 1
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 368
EP 370
DI 10.1038/353368a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400066
PM 1922343
DA 2026-03-10
ER

PT J
AU ITO, N
   PHILLIPS, SEV
   STEVENS, C
   OGEL, ZB
   MCPHERSON, MJ
   KEEN, JN
   YADAV, KDS
   KNOWLES, PF
AF ITO, N
   PHILLIPS, SEV
   STEVENS, C
   OGEL, ZB
   MCPHERSON, MJ
   KEEN, JN
   YADAV, KDS
   KNOWLES, PF
TI NOVEL THIOETHER BOND REVEALED BY A 1.7-A CRYSTAL-STRUCTURE OF GALACTOSE-OXIDASE
SO NATURE
LA English
DT Article
ID ribonucleotide reductase; superoxide-dismutase; radical site; copper; resolution; enzyme; identification; involvement; catalysis; system
AB GALACTOSE oxidase is an extracellular enzyme secreted by the fungus Dactylium dendroides.  It is monomeric, with a relative molecular mass of 68,000, catalyses the stereospecific oxidation of a broad range of primary alcohol substrates and possesses a unique mononuclear copper site essential for catalysing a two-electron transfer reaction during the oxidation of primary alcohols to corresponding aldehydes 1.  Recent evidence 2 arguing against a Cu(III)-Cu(I) couple 3 implies the existence of a second redox-active site proposed to involve pyrroloquinoline quinone 4 or a tyrosine radical 5,6.  We now report the crystal structure of galactose oxidase at 1.7 angstrom resolution.  This reveals a unique structural feature at the copper site with a novel thioether bond linking Cys 228 and Tyr 272 in a stacking interaction with Trp 290.  We propose that these molecular components stabilize the protein free-radical species essential for catalysis and thus provide a 'built-in' secondary cofactor.  This feature may represent a new mechanism for mediating electron transfer in metalloenzymes in the absence of exogenous cofactors.
RP ITO, N (corresponding author), UNIV LEEDS,DEPT BIOCHEM & MOLEC BIOL,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND.
NR 30
TC 734
Z9 816
U1 0
U2 83
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 87
EP 90
DI 10.1038/350087a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300073
PM 2002850
DA 2026-03-10
ER

PT J
AU SCHILLING, JG
AF SCHILLING, JG
TI FLUXES AND EXCESS TEMPERATURES OF MANTLE PLUMES INFERRED FROM THEIR INTERACTION WITH MIGRATING MIDOCEAN RIDGES
SO NATURE
LA English
DT Article
ID easter microplate evolution; pb isotope evidence; spreading center; south-atlantic; earths mantle; fuca ridge; convection; hotspots; islands; helium
AB The behaviour of thermal plumes in the Earth's upper mantle is strongly affected by their interaction with nearby mid-ocean ridges. The magnitude of the buoyant topography and the length of the geochemical anomaly induced by plumes at migrating ridge axes provide a way to estimate their excess temperature and discharge rate, and thereby constrain their depth of origin.
RP SCHILLING, JG (corresponding author), UNIV RHODE ISL,GRAD SCH OCEANOG,KINGSTON,RI 02881, USA.
NR 59
TC 341
Z9 369
U1 2
U2 37
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 397
EP 403
DI 10.1038/352397a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600054
DA 2026-03-10
ER

PT J
AU DELLAVALLE, M
   JARVIS, BJ
   WEST, RM
AF DELLAVALLE, M
   JARVIS, BJ
   WEST, RM
TI EVIDENCE FOR A BLACK-HOLE IN THE X-RAY NOVA MUSCAE 1991
SO NATURE
LA English
DT Article
ID a0620-00
AB X-RAY novae form a subclass of low-mass X-ray binaries, which typically consist of a neutron star accreting material from a low-mass, late-type companion. In a few cases, however-notably A0620-00 (ref. 1)-, the accreting object may be a black hole. The detection and study of the optical counterpart is then of great importance in understanding the origin of the X-ray emission and the nature of the companion. We report here the discovery of a new X-ray nova, Nova Muscae 1991, which we found in a search for the optical counterpart of the new transient X-ray source GRS1121-68. The optical position, light-curve and early spectral development of the outburst support the identification of Nova Muscae 1991 as a binary, and similarities with A0620-00 (known optically as V616 Mon) in its early evolutionary stages led us to classify Nova Muscae 1991 as a candidate black-hole binary.
RP DELLAVALLE, M (corresponding author), EUROPEAN SO OBSERV,CASILLA 19001,SANTIAGO 19,CHILE.
NR 23
TC 47
Z9 48
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 50
EP 52
DI 
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500052
DA 2026-03-10
ER

PT J
AU LEHMAN, SJ
   JONES, GA
   KEIGWIN, LD
   ANDERSEN, ES
   BUTENKO, G
   OSTMO, SR
AF LEHMAN, SJ
   JONES, GA
   KEIGWIN, LD
   ANDERSEN, ES
   BUTENKO, G
   OSTMO, SR
TI INITIATION OF FENNOSCANDIAN ICE-SHEET RETREAT DURING THE LAST DEGLACIATION
SO NATURE
LA English
DT Article
ID north-sea; norwegian channel; ocean circulation; sediments; history; norway; geology; sector; sweden; bp
AB ALTHOUGH the retreat history of the southern margin of the Laurentide ice sheet during the last deglaciation has been well known for several decades 1-3 and recently supported by evidence from accelerator mass spectrometer (AMS) radiocarbon dating of meltwater in the Gulf of Mexico 4 and the North Atlantic subtropical gyre 5, the retreat history of the Fennoscandian ice sheet before 13 kyr ago is still poorly documented. From AMS C-14 dating and isotopic analysis of a rapidly deposited series of supratill sediments in the Norwegian Channel (North Sea), we find that the southern margin of the Fennoscandian ice sheet was in retreat by 15 kyr BP (before present), approximately 2,000 yr earlier than previously supposed.  Oxygen isotope analyses in the channel sediments confirm earlier evidence from deep Norwegian Sea sediment cores for low salinity due to ice sheet discharge beginning approximately 15-14.5 kyr BP (ref. 6).  Recent recalibration of the C-14 timescale indicates that the onset of deglaciation within the Norwegian Sea occurred during an interval of rapidly increasing summer insolation beginning approximately 18,000 calendar yr BP (ref. 7), suggesting that ice-sheet retreat may have been caused by increasing insolation acting on a particularly climate-sensitive ice-sheet configuration.  Fresh water and icebergs discharged into the Norwegian Sea at this time reached the North Atlantic and may have contributed to a brief interval of extreme oceanic cooling 8 and reduced production of North Atlantic Deep Water 9,10. These factors may also have helped to briefly reverse the deglaciation trend (Erie Interstade) already underway in North America.
C1 UNIV OSLO,N-0316 OSLO 3,NORWAY.
   NORSK HYDRO AS,N-1321 STABEKK,NORWAY.
C3 University of Oslo; Norsk Hydro ASA
RP LEHMAN, SJ (corresponding author), WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543, USA.
NR 42
TC 123
Z9 124
U1 1
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 513
EP 516
DI 10.1038/349513a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100062
DA 2026-03-10
ER

PT J
AU HENRY, I
   BONAITIPELLIE, C
   CHEHENSSE, V
   BELDJORD, C
   SCHWARTZ, C
   UTERMANN, G
   JUNIEN, C
AF HENRY, I
   BONAITIPELLIE, C
   CHEHENSSE, V
   BELDJORD, C
   SCHWARTZ, C
   UTERMANN, G
   JUNIEN, C
TI UNIPARENTAL PATERNAL DISOMY IN A GENETIC CANCER-PREDISPOSING SYNDROME
SO NATURE
LA English
DT Article
ID wiedemann-beckwith syndrome; wilms tumor; adrenocortical carcinoma; chromosome-11; 11p15.5; alleles; trisomy; markers; locus
AB THE 11p15.5 region of human chromosome 11 seems to contain a locus or loci involved in congenital overgrowth anomalies as well as in the genesis of many tumours associated with the Beckwith-Wiedemann syndrome (BWS) 1-6.  Given the unusual differential parental allele involvement in the different aetiological forms of BWS 5, 7 and the loss of maternal alleles in associated tumours 8-10, we have now used 11p15.5 markers to determine the parental origin of chromosome 11 in eight sporadic cases of BWS.  Probands in three informative families had uniparental paternal disomy for region 11p15.5.  Further, an overall greatly increased frequency of homozygosity for several 11p15.5 markers in 21 sporadic BWS patients suggest that isodisomy probably accounts for an even higher proportion of BWS sporadic cases.  This demonstrates that uniparental paternal disomy can be associated with a genetic cancer-predisposing syndrome.
C1 INSERM,U155,F-75016 PARIS,FRANCE.
   INSERM,U129,F-75014 PARIS,FRANCE.
   GREENWOOD GENET CTR,GREENWOOD,SC 29646.
   UNIV INNSBRUCK,A-6020 INNSBRUCK,AUSTRIA.
C3 Institut National de la Sante et de la Recherche Medicale (Inserm); Institut National de la Sante et de la Recherche Medicale (Inserm); Greenwood Genetic Center; University of Innsbruck
RP HENRY, I (corresponding author), INSERM,U73,CHATEAU LONGCHAMP,F-75016 PARIS,FRANCE.
NR 23
TC 371
Z9 384
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 665
EP 667
DI 10.1038/351665a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200071
PM 1675767
DA 2026-03-10
ER

PT J
AU AMMALA, C
   LARSSON, O
   BERGGREN, PO
   BOKVIST, K
   JUNTTIBERGGREN, L
   KINDMARK, H
   RORSMAN, P
AF AMMALA, C
   LARSSON, O
   BERGGREN, PO
   BOKVIST, K
   JUNTTIBERGGREN, L
   KINDMARK, H
   RORSMAN, P
TI INOSITOL TRISPHOSPHATE-DEPENDENT PERIODIC ACTIVATION OF A CA2+ - ACTIVATED K+ CONDUCTANCE IN GLUCOSE-STIMULATED PANCREATIC BETA-CELLS
SO NATURE
LA English
DT Article
ID b-cells; electrical-activity; skeletal-muscle; channels; secretion; currents; tolbutamide; calcium; apamin; smooth
AB GLUCOSE-STIMULATED insulin secretion is associated with the appearance of electrical activity in the pancreatic beta-cell. At intermediate glucose concentrations, beta-cell electrical activity follows a characteristic pattern of slow oscillations in membrane potential on which bursts of action potentials are superimposed 1.  The electrophysiological background of the bursting pattern remains unestablished. Activation of Ca2+-activated large-conductance K+ channels (K(Ca) channel 12) has been implicated in this process 3 but seems unlikely in view of recent evidence demonstrating that the beta-cell electrical activity is unaffected by the specific K(Ca) channel blocker charybdotoxin 4.  Another hypothesis postulates that the bursting arises as a consequence of two components of Ca2+-current inactivation 5.  Here we show that activation of a novel Ca2+-dependent K+ current in glucose-stimulated-beta-cells produces a transient membrane repolarization. This interrupts action potential firing so that action potentials appear in bursts. Spontaneous activity of this current was seen only rarely but could be induced by addition of compounds functionally related to hormones and neurotransmitters present in the intact pancreatic islet. K+ currents of the same type could be evoked by intracellular application of GTP, the effect of which was mediated by mobilization of Ca2+ from inositol 1,4,5-trisphosphate (InsP3)-sensitive intracellular Ca2+ stores. These observations suggest that oscillatory glucose-stimulated electrical activity, which is correlated with pulsatile release of insulin 6, results from the interaction between the beta-cell and intraislet hormones and neurotransmitters. Our data also provide evidence for a close interplay between ion channels in the plasma membrane and InsP3-induced mobilization of intracellular Ca2+ in an excitable cell.
C1 GOTHENBURG UNIV,DEPT MED PHYS,BOX 33031,S-40033 GOTHENBURG,SWEDEN.
   KAROLINSKA INST,DEPT ENDOCRINOL,S-10401 STOCKHOLM 60,SWEDEN.
C3 University of Gothenburg; Karolinska Institutet
NR 31
TC 129
Z9 132
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 849
EP 852
DI 10.1038/353849a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200061
PM 1719424
DA 2026-03-10
ER

PT J
AU FRANCO, B
   GUIOLI, S
   PRAGLIOLA, A
   INCERTI, B
   BARDONI, B
   TONLORENZI, R
   CARROZZO, R
   MAESTRINI, E
   PIERETTI, M
   TAILLONMILLER, P
   BROWN, CJ
   WILLARD, HF
   LAWRENCE, C
   PERSICO, MG
   CAMERINO, G
   BALLABIO, A
AF FRANCO, B
   GUIOLI, S
   PRAGLIOLA, A
   INCERTI, B
   BARDONI, B
   TONLORENZI, R
   CARROZZO, R
   MAESTRINI, E
   PIERETTI, M
   TAILLONMILLER, P
   BROWN, CJ
   WILLARD, HF
   LAWRENCE, C
   PERSICO, MG
   CAMERINO, G
   BALLABIO, A
TI A GENE DELETED IN KALLMANNS SYNDROME SHARES HOMOLOGY WITH NEURAL CELL-ADHESION AND AXONAL PATH-FINDING MOLECULES
SO NATURE
LA English
DT Article
ID amino-acid-sequence; syndrome hypogonadotropic hypogonadism; human x-chromosome; distal short arm; immunoglobulin superfamily; steroid sulfatase; tyrosine kinase; messenger-rna; y-chromosome; cdna clone
AB Kallmann's syndrome (clinically characterized by hypogonadotropic hypogonadism and inability to smell) is caused by a defect in the migration of olfactory neurons, and neurons producing hypothalamic gonadotropin-releasing hormone.  A gene has now been isolated from the critical region on Xp22.3 to which the syndrome locus has been assigned:  this gene escapes X inactivation, has a homologue on the Y chromosome, and shows an unusual pattern of conservation across species.  The predicted protein has significant similarities with proteins involved in neural cell adhesion and axonal pathfinding, as well as with protein kinases and phosphatases, which suggests that this gene could have a specific role in neuronal migration.
C1 BAYLOR COLL MED,INST MOLEC GENET,1 BAYLOR PLAZA,HOUSTON,TX 77030.
   INST G GASLINI,GENOA,ITALY.
   NAPLES UNIV,DEPT PEDIAT,I-80138 NAPLES,ITALY.
   BAYLOR COLL MED,DEPT CELL BIOL,HOUSTON,TX 77030.
   INT INST GENET & BIOPHYS,I-80125 NAPLES,ITALY.
   WASHINGTON UNIV,SCH MED,CTR GENET MED,ST LOUIS,MO 63110.
   STANFORD UNIV,MED CTR,SCH MED,DEPT GENET,STANFORD,CA 94305.
   IST BIOCHIM GENET EVOLUZION ST,PAVIA,ITALY.
C3 Baylor College of Medicine; University of Genoa; IRCCS Istituto Giannina Gaslini; University of Naples Federico II; Baylor College of Medicine; Consiglio Nazionale delle Ricerche (CNR); Istituto di Genetica e Biofisica Adriano Buzzati-Traverso (IGB-CNR); Washington University (WUSTL); Stanford University
NR 60
TC 704
Z9 744
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 529
EP 536
DI 10.1038/353529a0
PG 8
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300057
PM 1922361
DA 2026-03-10
ER

PT J
AU ATWATER, BF
   STUIVER, M
   YAMAGUCHI, DK
AF ATWATER, BF
   STUIVER, M
   YAMAGUCHI, DK
TI RADIOCARBON TEST OF EARTHQUAKE MAGNITUDE AT THE CASCADIA SUBDUCTION ZONE
SO NATURE
LA English
DT Article
ID time scale; calibration; margin; fault; bc
AB THE Cascadia subduction zone, which extends along the northern Pacific coast of North America, might produce earthquakes of magnitude 8 or 9 ('great' earthquakes) even though it has not done so during the past 200 years of European observation 1-7.  Much of the evidence for past Cascadia earthquakes comes from former meadows and forests that became tidal mudflats owing to abrupt tectonic subsidence in the past 5,000 years 2,3,6,7.  If due to a great earthquake, such subsidence should have extended along more than 100 km of the coast 2.  Here we investigate the extent of coastal subsidence that might have been caused by a single earthquake, through high-precision radiocarbon dating of coastal trees that abruptly subsided into the intertidal zone. The ages leave the great-earthquake hypothesis intact by limiting to a few decades the discordance, if any, in the most recent subsidence of two areas 55 km apart along the Washington coast. This subsidence probably occurred about 300 years ago.
C1 UNIV COLORADO,INST ARCTIC & ALPINE RES,CTR GEOCHRONOL RES,BOULDER,CO 80309.
   UNIV WASHINGTON,QUATERNARY RES CTR,SEATTLE,WA 98195.
   UNIV COLORADO,INST ARCTIC & ALPINE RES,MT RES STN,BOULDER,CO 80309.
C3 University of Colorado System; University of Colorado Boulder; University of Washington; University of Washington Seattle; University of Colorado System; University of Colorado Boulder
RP ATWATER, BF (corresponding author), UNIV WASHINGTON,DEPT GEOL SCI,US GEOL SURVEY,SEATTLE,WA 98195, USA.
NR 17
TC 79
Z9 89
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 156
EP 158
DI 10.1038/353156a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100050
DA 2026-03-10
ER

PT J
AU MARTEN, I
   LOHSE, G
   HEDRICH, R
AF MARTEN, I
   LOHSE, G
   HEDRICH, R
TI PLANT-GROWTH HORMONES CONTROL VOLTAGE-DEPENDENT ACTIVITY OF ANION CHANNELS IN PLASMA-MEMBRANE OF GUARD-CELLS
SO NATURE
LA English
DT Article
ID protoplasts; auxin
AB THE opening of stomatal pores in the epidermis of plant leaves is caused by an increase in turgor pressure of the guard cells as a result of the accumulation of potassium salts 1,2. Although growth hormones have been shown to affect stomatal opening 3, the transduction pathways by which growth regulators exert their effects on stomatal action are largely unknown. Here we report that auxins can elicit stomatal opening. These phytohormones modulate anion channels 4,5 in the plasma membrane in what may be an initial step in regulated volume increase in guard cells. Our patch-clamp experiments demonstrate that auxins can directly interact with the extracellular face of the channel. As a result, its activation potential is shifted towards the resting potential of the cell to favour transient channel opening.
C1 UNIV GOTTINGEN,INST PFLANZENPHYSIOL,W-3400 GOTTINGEN,GERMANY.
C3 University of Gottingen
NR 17
TC 140
Z9 148
U1 3
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 758
EP 762
DI 10.1038/353758a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600070
DA 2026-03-10
ER

PT J
AU STUART, WD
AF STUART, WD
TI SEISMIC QUIESCENCE AT PARKFIELD DUE TO DETACHMENT FAULTING
SO NATURE
LA English
DT Article
ID california
AB ON the San Andreas fault near Parkfield, California, rates of seismicity1,2 and geodetic line shortening3,4 have been lower since 1986 than before.  Wyss et al.1,3 interpret the rate decreases as precursors to an imminent moderate earthquake (magnitude M = 5.5-6) and estimate the earthquake time to be March 1991 +/- 1 yr.  The earthquake was previously predicted to occur in 1988 +/- 5 yr based on five of six similar earthquakes which occurred at intervals approximately 22 yr, the last one in 1966(5).  Here I present a model that attributes the rate changes to the initiation of slip on a subhorizontal detachment fault under the pending rupture area.  In this model, the slip starts late in the seismic cycle, and diminishes the loading rate on the nearby San Andreas, thus acting as a buffer.
RP STUART, WD (corresponding author), US GEOL SURVEY,PASADENA,CA 91106, USA.
NR 13
TC 8
Z9 8
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 58
EP 61
DI 10.1038/349058a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100049
DA 2026-03-10
ER

PT J
AU BEST, JL
   ROY, AG
AF BEST, JL
   ROY, AG
TI MIXING-LAYER DISTORTION AT THE CONFLUENCE OF CHANNELS OF DIFFERENT DEPTH
SO NATURE
LA English
DT Article
ID junctions; flow; morphology; separation
AB CHANNEL confluences have received considerable recent attention in the fields of geomorphology 1-3, sedimentology 4-9 and hydraulic engineering 10-13.  Where channels join, rapid changes in fluid velocity, turbulence intensity, channel hydraulic geometry and bed geometry may occur 14-17.  Previous models of junction dynamics have tended to assume that the confluent channels are of equal depth 10,18, a condition that may be found only rarely in natural junctions; more often, the depths of confluent channels are different 19.  This discordance is commonly the result of the formation, at the mouth of each confluent channel, of bars that possess steep avalanche faces which dip into a central junction scour 1,2,5,20.  Here we suggest that when channels of different depth join, the mixing layer that forms at their confluence is distorted by interacting with a separation zone which forms in the lee of the mouth of the shallower channel.  This mixing-layer distortion imparts a complex three-dimensional flow to the junction, promoting vertical fluid upwelling and significantly enhancing rapid mixing within the flow of the shallow tributary, while retarding the rate of mixing across the flow of the deeper channel.  Suspended sediments or contaminants within the deeper channel may be transferred rapidly across the flow of the shallower tributary, upwelling downstream of the junction.
C1 UNIV MONTREAL,DEPT GEOG,MONTREAL H3C 3J7,QUEBEC,CANADA.
C3 Universite de Montreal
RP BEST, JL (corresponding author), UNIV LEEDS,DEPT EARTH SCI,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND.
NR 24
TC 172
Z9 191
U1 0
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 411
EP 413
DI 10.1038/350411a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200045
DA 2026-03-10
ER

PT J
AU HUNTRESS, WT
   ALLEN, M
   DELITSKY, M
AF HUNTRESS, WT
   ALLEN, M
   DELITSKY, M
TI CARBON SUBOXIDE IN COMET HALLEY
SO NATURE
LA English
DT Article
ID electron-impact ionization; induced chemical-reactions; hydrogen mixture; ion composition; dust particles; p/halley; giotto; emission; monoxide; gas
AB OBSERVATIONAL data acquired during the recent appearance of comet Halley pose a puzzle about the nature and distribution of elemental carbon and carbonaceous material in its nucleus and coma. The nucleus is darker even than coal (albedo < 4%) 1, suggesting that its volatile ices contain a few per cent of carbonaceous material in the form of graphitic or amorphous carbon. The very high abundance of light elements in the coma dust 2,3, particularly H, C, N and O, suggests the presence of a significant organic component. The emission feature near 3.4-mu-m also implies the presence of organic material in the dust 4-6.  But the parent species for the primary carbon-containing material that have been identified so far (such as CO, CO2 and CH4) are not present in sufficient quantities to account for all of it. Here we propose that an additional contribution from carbon suboxide (C3O2) in the coma dust and the nucleus material is consistent with the observational data. A production rate in the coma for C3O2 of about 0.03-0.04 times that of water would provide the distributed source of elemental carbon and CO within 10(4) km of the nucleus that is required to explain the data from the Giotto spacecraft and from ground-based observations.
C1 CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,4800 OAK GROVE DR,PASADENA,CA 91109.
   CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125.
   NASA,DIV SOLAR SYST EXPLORAT,WASHINGTON,DC 20546.
C3 California Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; National Aeronautics & Space Administration (NASA)
NR 46
TC 55
Z9 58
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 316
EP 318
DI 10.1038/352316a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900063
DA 2026-03-10
ER

PT J
AU VANPARADIJS, J
AF VANPARADIJS, J
TI HIGH-ENERGY BACKGROUND-RADIATION FROM QUIESCENT GAMMA-RAY BURST SOURCES
SO NATURE
LA English
DT Article
ID neutron star models; constraints; absorption; cyclotron; features; origin
AB COSMIC gamma-ray bursts (GRBs) were discovered 1 20 years ago, but remain puzzling. The detection 2-4 of cyclotron harmonics in the spectra of some GRBs suggests an origin in magnetized neutron stars, but there is no consensus on the energy source or the mechanism that generates the gamma-rays. Statistical analysis 5 of the spatial distribution of GRBs indicates an origin in our Galaxy, and it has been proposed that they are caused by thermonuclear flashes in accreted material on the surface of strongly magnetized neutron stars 6-9. I point out here that, in this model, accretion during the quiescent intervals between bursts will generate a diffuse background emission from what may be a very large number of objects, too faint to be individually detected. Because the quiescent emission is related directly to the observed intensity and frequency of GRBs throughout the Galaxy, measurement of the diffuse background in the appropriate energy band may provide a test of the thermonuclear-flash model which is independent of the distance scale to GRB sources, the possible emission anisotropy of both burst and quiescent radiation, and the accretion rates and recurrence times of individual sources.
C1 NATL INST NUCL PHYS & HIGH ENERGY PHYS,CTR HIGH ENERGY ASTROPHYS,1098 SJ AMSTERDAM,NETHERLANDS.
   UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106.
C3 University of California System; University of California Santa Barbara
RP VANPARADIJS, J (corresponding author), UNIV AMSTERDAM,ASTRON INST ANTON PANNEKOEK,KRUISLAAN 403,1098 SJ AMSTERDAM,NETHERLANDS.
NR 31
TC 1
Z9 1
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 730
EP 731
DI 10.1038/353730a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600058
DA 2026-03-10
ER

PT J
AU RAYMOND, M
   CALLAGHAN, A
   FORT, P
   PASTEUR, N
AF RAYMOND, M
   CALLAGHAN, A
   FORT, P
   PASTEUR, N
TI WORLDWIDE MIGRATION OF AMPLIFIED INSECTICIDE RESISTANCE GENES IN MOSQUITOS
SO NATURE
LA English
DT Article
ID organo-phosphate resistance; culex-pipiens l; drosophila-melanogaster; l diptera; quinquefasciatus diptera; detoxifying esterases; alcohol-dehydrogenase; culicidae; complex; populations
AB IN Culex pipiens, overproduction of nonspecific esterases is a common mechanism of resistance to organophosphate insecticides 1,2.  The esterases are attributed to closely linked loci named A and B according to substrate preference 3-6, and overproduction of all esterases B is due to gene amplification 7,8.  Distribution of electrophoretically distinct variants of overproduced esterases A and B is geographically restricted, with the exception of esterases A2 and B2, always found together throughout at least three continents (Fig. 1).  To determine whether this situation is due to migration or to a high mutation rate, esterase B structural genes and their flanking regions were compared by sequence and/or restriction fragment length polymorphism analysis.  Whereas structural genes were similar, flanking regions of electrophoretically dissimilar esterases B varied considerably.  In contrast, flanking sequences of esterases B2 from different geographical locations (Africa, Asia, North America) were identical.  These results suggest that amplified esterase B2 genes originated from an initial event that has subsequently spread organophosphate insecticide resistance by migration.
C1 UNIV MONTPELLIER 2,BIOL MOLEC LAB,URA 1191,F-34095 MONTPELLIER,FRANCE.
C3 Universite de Montpellier
RP RAYMOND, M (corresponding author), INST SCI EVOLUT,GENET & ENVIRONM LAB,URA 327,CASE COURRIER 64,F-34095 MONTPELLIER,FRANCE.
NR 33
TC 269
Z9 308
U1 1
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 151
EP 153
DI 10.1038/350151a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500057
PM 2005964
DA 2026-03-10
ER

PT J
AU NOEBELS, JL
   MARCOM, PK
   JALILIANTEHRANI, MH
AF NOEBELS, JL
   MARCOM, PK
   JALILIANTEHRANI, MH
TI SODIUM-CHANNEL DENSITY IN HYPOMYELINATED BRAIN INCREASED BY MYELIN BASIC-PROTEIN GENE DELETION
SO NATURE
LA English
DT Article
ID action-potential conduction; dysmyelinating mutant mice; central nervous-system; shiverer mouse; optic-nerve; rat; expression; differentiation; glycoprotein; deficient
AB TROPHIC control over the expression and membrane distribution of voltage-dependent ion channels is one of the principal organizing events underlying the maturation of excitable cells. The myelin sheath is a major structural determinant of regional ion channel topography in central axons 1,2, but the exact molecular signals that mediate local interactions between the oligodendrocyte and axolemma are not known. We have found that large caliber fibre pathways in the brain of the mutant mouse shiverer (shi, gene on chromosome 18), whose developmental fate of myelination is averted by deletion of five exons in the myelin basic protein gene 3-5, have a striking excess of sodium channels. As cytoplasmic membranes of shiverer oligodendroglia still adhere to axons 6-8, the evidence indicates that myelin basic protein or a myelin basic protein-dependent glial transmembrane signal associated with compact myelin formation, rather than a simple glial-axon contact inhibition or an intrinsic genetic program of neuronal differentiation, could be critical in downregulating sodium channel density in axons. Here we use the shiverer mutant to show that mature central nervous system projection neurons with large caliber unmyelinated fibres sustain functional excitability by increasing sodium channel density. This axon plasticity, triggered by the absence of a single glial protein, contributes to the unexpectedly mild degree of neurological impairment in the mutant brain without myelin, and may be a potentially inducible mechanism determining the recovery of function from dysmyelinating disease.
C1 BAYLOR UNIV,DEPT BIOCHEM,HOUSTON,TX 77030.
C3 Baylor University
RP NOEBELS, JL (corresponding author), BAYLOR UNIV,INST MOLEC GENET,DEPT NEUROL,DIV NEUROSCI,NEUROPHYSIOL SECT,DEV NEUROGENET LAB,HOUSTON,TX 77030, USA.
NR 30
TC 56
Z9 60
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 431
EP 434
DI 10.1038/352431a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600065
PM 1713650
DA 2026-03-10
ER

PT J
AU GORG, A
AF GORG, A
TI 2-DIMENSIONAL ELECTROPHORESIS
SO NATURE
LA English
DT Article
ID immobilized ph gradients; polyacrylamide-gel electrophoresis; two-dimensional electrophoresis; basic myeloid polypeptides; 1st dimension; proteins
RP GORG, A (corresponding author), TECH UNIV MUNICH,INST FOOD TECHNOL,W-8050 FREISING,GERMANY.
NR 14
TC 73
Z9 80
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 545
EP 546
DI 10.1038/349545a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100074
DA 2026-03-10
ER

PT J
AU REGNIER, FE
AF REGNIER, FE
TI PERFUSION CHROMATOGRAPHY
SO NATURE
LA English
DT Article
ID liquid-chromatography; proteins
AB Perfusion chromatography is a technique based on fluid dynamics for reducing stagnant mobile phase mass transfer in liquid chromatography.  This is achieved by using supports with large pores that allow mobile phase to flow through particles.
RP REGNIER, FE (corresponding author), PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907, USA.
NR 13
TC 139
Z9 145
U1 0
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 634
EP 635
DI 10.1038/350634a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200068
PM 2017260
DA 2026-03-10
ER

PT J
AU RASHBASS, P
   COOKE, LA
   HERRMANN, BG
   BEDDINGTON, RSP
AF RASHBASS, P
   COOKE, LA
   HERRMANN, BG
   BEDDINGTON, RSP
TI A CELL AUTONOMOUS FUNCTION OF BRACHYURY IN T/T EMBRYONIC STEM-CELL CHIMERAS
SO NATURE
LA English
DT Article
ID mesoderm formation; mouse embryo; t-gene; inversion; mutation; complex; locus
AB DEVELOPMENTAL genetics has shown that the Brachyury (T) gene has a key role in mesoderm formation during gastrulation in the mouse 1,2.  Homozygous embryos (Fig. 1) have a defective allantois, degenerate or absent notochord and disrupted primitive streak and node.  The neural tube is kinked and somite formation interrupted 3-6.  The T gene has been cloned 7 and is expressed during the early stages of gastrulation, being restricted to the primitive streak region, nascent mesoderm and notochord 8.  Neither the sequence of the gene nor its expression pattern define its developmental function 7,9.  To study the cell autonomy of the T mutation we have isolated and genetically characterized embryonic stem cell lines and studied their behaviour in chimaeras.  T/+ embryonic stem cells form normal chimaeras, whereas T/T <-> +/+ chimaeras mimic the T/T mutant phenotype.   The results indicate that the T gene acts cell autonomously in the primitive streak and notochord but may activate a signalling pathway involved in the specification of other mesodermal tissues.
C1 MAX PLANCK INST ENTWICKLUNGSBIOL,W-7400 TUBINGEN,GERMANY.
C3 Max Planck Society
RP RASHBASS, P (corresponding author), AFRC,CTR GENOME RES,KINGS BLDG,EDINBURGH EH9 3JQ,MIDLOTHIAN,SCOTLAND.
NR 22
TC 94
Z9 102
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 348
EP 351
DI 10.1038/353348a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400059
PM 1922339
DA 2026-03-10
ER

PT J
AU ELSNER, JB
   TSONIS, AA
AF ELSNER, JB
   TSONIS, AA
TI DO BIDECADAL OSCILLATIONS EXIST IN THE GLOBAL TEMPERATURE RECORD
SO NATURE
LA English
DT Article
ID co2 concentration; climate; dynamics; model
AB MODELS predict 1-3 that increasing atmospheric concentrations of greenhouse gases will result in an increase in the global mean temperature over the next few decades and beyond.  It is therefore important to be able to distinguish a warming trend from natural variability in the time series of global temperatures.  Recently, Ghil and Vautard 4 applied singular spectrum analysis to a record of global surface air temperatures, and identified a secular warming trend and a small number of oscillatory modes.  The oscillations had interdecadal periods of 21 and 16 years (attributed to changes in the extratropical ocean circulation), and interannual periods of 6 and 5 years (attributed to the El Nino/Southern Oscillation).  Here we re-analyse the data by considering various lengths of the temperature record, and we apply singular spectrum analysis to five other temperature records (two global, three hemispheric).  Our results offer no support for the presence of bidecadal oscillations in the global surface temperature records.
C1 UNIV WISCONSIN,DEPT GEOSCI,MILWAUKEE,WI 53201.
C3 University of Wisconsin System; University of Wisconsin Milwaukee
RP ELSNER, JB (corresponding author), FLORIDA STATE UNIV,DEPT METEOROL,TALLAHASSEE,FL 32306, USA.
NR 17
TC 38
Z9 41
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 551
EP 553
DI 10.1038/353551a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300064
DA 2026-03-10
ER

PT J
AU WOLFE, JA
AF WOLFE, JA
TI PALEOBOTANICAL EVIDENCE FOR A JUNE IMPACT WINTER AT THE CRETACEOUS TERTIARY BOUNDARY
SO NATURE
LA English
DT Article
ID extinction; spherules; mexico
AB A LARGE bolide impact, such as that thought to have occurred at the Cretaceous/Tertiary (K/T) boundary, should produce large amounts of light-attenuating debris, thereby causing an 'impact winter' 1-3.  Because of thermal buffering in the oceans, evidence for a brief (1-2 months 2-4) impact winter would be found only in terrestrial environments. Aquatic leaves in the K/T boundary section near Teapot Dome, Wyoming, preserve structural deformation that can be duplicated experimentally in extant aquatic leaves by freezing. Reproductive stages reached by the fossil aquatic plants at the time of death suggest that freezing took place in approximately early June. Both the existence of the structurally deformed plants and the high abundance of fern spores occur in a horizon containing sparse impact debris, but below the horizon containing abundant impact debris; I therefore suggest that the lower horizon represents debris and effects from a large, distant bolide impact, and the upper horizon represents a small, nearby bolide impact.
RP WOLFE, JA (corresponding author), US GEOL SURVEY,DENVER FED CTR,MS-919,BOX 25046,DENVER,CO 80225, USA.
NR 24
TC 53
Z9 54
U1 1
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 420
EP 423
DI 10.1038/352420a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600060
DA 2026-03-10
ER

PT J
AU GREENWADE, LE
AF GREENWADE, LE
TI SCIENTIFIC VISUALIZATION - PRACTICES AND PROMISES
SO NATURE
LA English
DT Article
RP GREENWADE, LE (corresponding author), IDAHO NATL ENGN LAB, IDAHO FALLS, ID 83415 USA.
NR 10
TC 0
Z9 1
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 191
EP 192
DI 10.1038/353191a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100061
PM 1891047
DA 2026-03-10
ER

PT J
AU PALMER, MS
   DRYDEN, AJ
   HUGHES, JT
   COLLINGE, J
AF PALMER, MS
   DRYDEN, AJ
   HUGHES, JT
   COLLINGE, J
TI HOMOZYGOUS PRION PROTEIN GENOTYPE PREDISPOSES TO SPORADIC CREUTZFELDT-JAKOB DISEASE
SO NATURE
LA English
DT Article
ID gerstmann-straussler syndrome; gene; dementia; mice
AB THE human prion diseases, Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler syndrome (GSS), are neurodegenerative diseases that are unique in being both infectious and genetic. Transmission of both diseases and the animal spongiform encephalopathies (for example, scrapie and bovine spongiform encephalopathy) to experimental animals by intracerebral inoculation with brain homogenates is well documented 1.  Despite their experimental transmissibility, missense and insertional mutations in the prion protein gene are associated with both GSS and familial CJD, demonstrating that the human familial cases are autosomal dominant diseases 2-6.  More that 80% of CJD cases occur sporadically, however, and are not known to be associated with mutations. Here we report that 21 of 22 sporadic CJD cases and a further 19 of 23 suspected sporadic CJD cases are homozygous at the polymorphic amino-acid residue 129; 51% of the normal population are heterozygous at this site. We argue that homozygosity predisposes towards sporadic CJD and that this directly supports the hypothesis that interaction between prion protein molecules underlies the disease process.
C1 ST MARYS HOSP,SCH MED,DEPT BIOCHEM & MOLEC GENET,PRION DIS GRP,NORFOLK PL,LONDON W2 1PG,ENGLAND.
   RADCLIFFE INFIRM,DEPT NEUROPATHOL,OXFORD OX2 6HE,ENGLAND.
C3 Imperial College London; Radcliffe Infirmary
FU Wellcome Trust Funding Source: Medline
NR 21
TC 760
Z9 828
U1 0
U2 46
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 340
EP 342
DI 10.1038/352340a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900072
PM 1677164
DA 2026-03-10
ER

PT J
AU STOCKER, TF
   WRIGHT, DG
AF STOCKER, TF
   WRIGHT, DG
TI RAPID TRANSITIONS OF THE OCEANS DEEP CIRCULATION INDUCED BY CHANGES IN SURFACE-WATER FLUXES
SO NATURE
LA English
DT Article
ID temperature; mode
AB DEEP water in the world's oceans flows predominantly from the northern North Atlantic into the Pacific 1, slowly upwells on the way to become part of the upper warm-water circulation, and returns to the North Atlantic. The stability of this thermohaline conveyor belt has recently been questioned on the basis of palaeoclimatic data from deep-sea sediment and ice cores 2,3. Different modes of deep circulation have been confirmed in numerical ocean models 4-6, and the present-day circulation has been shown to be sensitive to changes in the surface-water budget 7.  Here we use an idealized mode 4,5 to examine the hypothesis that small changes in the atmospheric flux of fresh water from the Atlantic to the Pacific could force the thermohaline circulation to switch between two stable modes. Our results indicate that a decrease of this flux can reverse the Atlantic circulation, although the Pacific thermohaline circulation does not change direction. This is consistent with reconstructions of conditions in the Atlantic Ocean during the last glacial obtained from deep-sea cores 8.  To reestablish the conveyor belt, the fresh-water flux need be increased only slightly beyond its present value.
C1 MCGILL UNIV,CTR CLIMATE & GLOBAL CHANGE RES,MONTREAL H3A 2K6,QUEBEC,CANADA.
   FISHERIES & OCEANS CANADA,BEDFORD INST OCEANOG,DARTMOUTH B2Y 4A2,NS,CANADA.
C3 McGill University; Bedford Institute of Oceanography; Fisheries & Oceans Canada
NR 17
TC 270
Z9 289
U1 0
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 729
EP 732
DI 10.1038/351729a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100058
DA 2026-03-10
ER

PT J
AU DUCKER, WA
   SENDEN, TJ
   PASHLEY, RM
AF DUCKER, WA
   SENDEN, TJ
   PASHLEY, RM
TI DIRECT MEASUREMENT OF COLLOIDAL FORCES USING AN ATOMIC FORCE MICROSCOPE
SO NATURE
LA English
DT Article
ID internal-reflection microscopy; electrolyte-solutions; surface forces; mica surfaces; separation
AB THE forces between colloidal particles dominate the behaviour of a great variety of materials, including paints, paper, soil, clays and (in some circumstances) cells. Here we describe the use of the atomic force microscope to measure directly the force between a planar surface and an individual colloid particle. The particle, a silica sphere of radius 3.5-mu-m, was attached to the force sensor in the microscope and the force between the particle and the surface was measured in solutions of sodium chloride. The measurements are consistent with the double-layer theory 1,2 of colloidal forces, although at very short distances there are deviations that may be attributed to hydration forces 3-6 or surface roughness, and with previous studies on macroscopic systems 4-6.  Similar measurements should be possible for a wide range of the particulate and fibrous materials that are often encountered in industrial contexts, provided that they can be attached to the microscope probe.
C1 AUSTRALIAN NATL UNIV,RES SCH PHYS SCI,DEPT APPL MATH,CANBERRA,ACT 2600,AUSTRALIA.
   AUSTRALIAN NATL UNIV,FAC SCI,DEPT CHEM,CANBERRA,ACT 2600,AUSTRALIA.
C3 Australian National University; Australian National University
NR 28
TC 1825
Z9 2028
U1 3
U2 486
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 239
EP 241
DI 10.1038/353239a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400052
DA 2026-03-10
ER

PT J
AU BRADDOCK, M
   THORBURN, AM
   KINGSMAN, AJ
   KINGSMAN, SM
AF BRADDOCK, M
   THORBURN, AM
   KINGSMAN, AJ
   KINGSMAN, SM
TI BLOCKING OF TAT-DEPENDENT HIV-1 RNA MODIFICATION BY AN INHIBITOR OF RNA POLYMERASE-II PROCESSIVITY
SO NATURE
LA English
DT Article
ID human immunodeficiency virus; long terminal repeat; trans-activation; unwinding activity; mammalian-cells; expression; elongation; protein
AB HUMAN immunodeficiency virus gene expression is regulated transcriptionally and post-transcriptionally 1-4 by the virally encoded tat protein (Tat).  Tat functions through an RNA target sequence located in the untranslated region at the 5' end of viral transcripts 5-8.  In Xenopus oocytes, translation of RNA containing the target sequence is specifically activated by Tat.  This activation only occurs if the RNA is injected into the nucleus, and might be due to a Tat-dependent, nucleus-specific chemical modification of the RNA which somehow facilitates translation 8.  Here we demonstrate that Tat activation of its target RNA in the nucleus involves a Tat-dependent covalent modification.  The modified RNA is competent for translation after reinjection into either the nucleus or the cytoplasm in the absence of Tat.  Furthermore, we find that the nucleoside analogue 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, which inhibits processivity of RNA polymerase II (ref. 9), blocks this Tat-dependent modification.
C1 DEPT BIOCHEM,VIRUS MOLEC BIOL GRP,S PARKS RD,OXFORD OX1 3QU,ENGLAND.
   BRITISH BIOTECHNOL LTD,OXFORD OX4 5LY,ENGLAND.
C3 University of Oxford
NR 23
TC 48
Z9 51
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 439
EP 441
DI 10.1038/350439a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200056
PM 2011194
DA 2026-03-10
ER

PT J
AU ACHAORBEA, H
   SHAKHOV, AN
   SCARPELLINO, L
   KOLB, E
   MULLER, V
   VESSAZSHAW, A
   FUCHS, R
   BLOCHLINGER, K
   ROLLINI, P
   BILLOTTE, J
   SARAFIDOU, M
   MACDONALD, HR
   DIGGELMANN, H
AF ACHAORBEA, H
   SHAKHOV, AN
   SCARPELLINO, L
   KOLB, E
   MULLER, V
   VESSAZSHAW, A
   FUCHS, R
   BLOCHLINGER, K
   ROLLINI, P
   BILLOTTE, J
   SARAFIDOU, M
   MACDONALD, HR
   DIGGELMANN, H
TI CLONAL DELETION OF V-BETA 14-BEARING T-CELLS IN MICE TRANSGENIC FOR MAMMARY-TUMOR VIRUS
SO NATURE
LA English
DT Article
ID major histocompatibility complex; long terminal repeat; positive selection; proviral dna; mouse; receptor; tolerance; region; mlsa; determinants
AB Autoreactive T lymphocytes are clonally deleted during maturation in the thymus.  Deletion of T cells expressing particular receptor V-beta elements is controlled by poorly defined autosomal dominant genes.  A gene has now been identified by expression of transgenes in mice which causes deletion of V-beta-14+ T cells.  The gene lies in the open reading frame of the long terminal repeat of the mouse mammary tumour virus.
C1 UNIV ZURICH,INST IMMUNOL & VIROL,CH-8051 ZURICH,SWITZERLAND.
   SWISS INST EXPTL CANC RES,CH-1066 EPALINGES,SWITZERLAND.
C3 University of Zurich; Swiss Institute Experimental Cancer Research
RP ACHAORBEA, H (corresponding author), LUDWIG INST CANC RES,LAUSANNE BRANCH,CH-1066 EPALINGES,SWITZERLAND.
NR 51
TC 318
Z9 328
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 207
EP 211
DI 10.1038/350207a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900047
PM 1848685
DA 2026-03-10
ER

PT J
AU RODRIGUEZ, JM
   KO, MKW
   SZE, ND
AF RODRIGUEZ, JM
   KO, MKW
   SZE, ND
TI ROLE OF HETEROGENEOUS CONVERSION OF N2O5 ON SULFATE AEROSOLS IN GLOBAL OZONE LOSSES
SO NATURE
LA English
DT Article
ID stratospheric ozone; northern-hemisphere; dimensional model; nitric-acid; trace gases; chemistry; chlorine; o-3; clo
AB THERE is a serious discrepancy between estimates of the downward trend in the column abundance of ozone at middle and high latitudes derived from ground-based and satellite data, and those obtained by models that calculate the effect of increases in atmospheric chlorine concentrations, but include only gas-phase chemistry 1,2.  Recent measurements 3,4 of the reaction rate of N2O5 on sulphate aerosols yield very fast rates for a wide range of water content, indicating that this reaction could take place in the stratospheric sulphate aerosol layer, which is present around the globe and year-round between approximately 14-25 km altitude.  Here we include this reaction in a two-dimensional model and find that the calculated decadal ozone trends at both high and middle latitudes agree much more closely with the trends deduced from observations.  Inclusion of the reaction also significantly increases the predicted concentrations of key species such as OH, CIO and HNO3, and decreases those of NO and NO2.  Measurements of these species in and near the sulphate layer are needed to confirm the importance of this reaction in the observed decrease of atmospheric ozone.
RP RODRIGUEZ, JM (corresponding author), ATMOSPHER & ENVIRONM RES INC,CAMBRIDGE,MA 02139, USA.
NR 26
TC 189
Z9 197
U1 2
U2 20
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 134
EP 137
DI 10.1038/352134a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700047
DA 2026-03-10
ER

PT J
AU YIN, QF
   HEESCHEN, DS
AF YIN, QF
   HEESCHEN, DS
TI 2 RADIO SUPERNOVAE IN THE UNUSUAL GALAXY MARKARIAN-297
SO NATURE
LA English
DT Article
ID 1.49 ghz; emission
AB STARBURST galaxies have higher star formation and supernova rates than normal galaxies, triggered in many cases by the interaction of two galaxies 1. Direct estimates of the supernova rate in starburst galaxies is difficult, because optical direction of supernovae is hampered by high background brightness and by dust 2, both of which are associated with the starburst phenomenon. Radio observations do not suffer from these problems. We report here the discovery of two radio supernovae in the clumpy irregular galaxy Markarian 297 (Mkn 297, also known as NGC6052), which has been estimated 3 to have a star formation rate ten times that of a normal spiral galaxy, and a supernova rate of 0.3-0.5 per year. It may consist of two interacting galaxies 4. A variable radio source found in 1982 (ref. 5) was attributed to possible supernova activity, and our observations with the Very Large Array, combined with earlier published data, define a reasonable radio light curve for a supernova that exploded in July 1979. The variability resembles that of the young supernova SN1986J (ref. 6), but at maximum the supernova in Mkn 297 would have been about six times as bright. We also identify a second source in the galaxy as a supernova. The presence of two extraordinarily bright supernovae in the same region may be a particular result of the interaction between two galaxies.
RP YIN, QF (corresponding author), NATL RADIO ASTRON OBSERV,EDGEMONT RD,CHARLOTTESVILLE,VA 22903, USA.
NR 11
TC 17
Z9 18
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 130
EP 132
DI 10.1038/354130a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000052
DA 2026-03-10
ER

PT J
AU BURROWS, DN
   MENDENHALL, JA
AF BURROWS, DN
   MENDENHALL, JA
TI SOFT-X-RAY SHADOWING BY THE DRACO CLOUD
SO NATURE
LA English
DT Article
ID h-i structure; magellanic cloud; emission; limits; flux
AB THE astronomical soft X-ray background has both extragalactic and, at lower energies, galactic components.  Using the Roentgen Astronomy Satellite (ROSAT), we have detected shadowing of the X-ray background in the 1/4 keV band (presumed to be of galactic origin) by the unusual interstellar cloud in Draco.  The Draco cloud is at high galactic latitude and, at several hundred parsecs distance from the Sun, is well away from the galactic plane.  It reduces the 1/4 keV emission by 63% relative to the adjacent sky, implying that a substantial contribution to the X-ray background in this direction comes from hot gas beyond the cloud.  This is the first direct evidence for a million-degree galactic halo of gas, but the significance of this observation for understanding the global diffuse X-ray background is unclear, as it contradicts earlier studies 1-3 which failed to find shadowing by galactic gas.  More observations of this sort, covering objects distributed throughout the galaxy, are needed to explore the morphology of the hot and cold gas in the nearby interstellar medium.
RP BURROWS, DN (corresponding author), PENN STATE UNIV,DEPT ASTRON & ASTROPHYS,525 DAVEY LAB,UNIVERSITY PK,PA 16802, USA.
NR 22
TC 144
Z9 152
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 629
EP 631
DI 10.1038/351629a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200056
DA 2026-03-10
ER

PT J
AU SAKAI, K
   MIYASHITA, Y
AF SAKAI, K
   MIYASHITA, Y
TI NEURAL ORGANIZATION FOR THE LONG-TERM-MEMORY OF PAIRED ASSOCIATES
SO NATURE
LA English
DT Article
ID inferior temporal neurons; cortex; monkey; lobectomy; correlate; stimulus; macaque
AB MOST of our long-term memories of episodes or objects are organized so that we can retrieve them by association. Clinical neuropsychologists assess human memory by the paired-associate learning test, in which a series of paired words or figures is presented and the subject is then asked to retrieve the other pair member associated with each cue 1. Patients with lesions of the temporal lobe show marked impairment in this test 2-6. In our study, we trained monkeys in a pair-association task 7 using a set of computer-generated paired patterns. We found two types of task-related neurons in the anterior temporal cortex. One type selectively responded to both pictures of the paired associates. The other type, which had the strongest response to one picture during the cue presentation, exhibited increasing activity during the delay period when the associate of that picture was used as a cue. These results provide new evidence that single neurons acquire selectivity for visual patterns through associative learning. They also indicate neural mechanisms for storage and retrieval in the long-term memory of paired associates.
RP SAKAI, K (corresponding author), UNIV TOKYO,SCH MED,DEPT PHYSIOL,7-3-1 HONGO,BUNKYO KU,TOKYO 113,JAPAN.
NR 25
TC 539
Z9 607
U1 0
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 152
EP 155
DI 10.1038/354152a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000061
PM 1944594
DA 2026-03-10
ER

PT J
AU SUNAHARA, RK
   GUAN, HC
   ODOWD, BF
   SEEMAN, P
   LAURIER, LG
   NG, G
   GEORGE, SR
   TORCHIA, J
   VANTOL, HHM
   NIZNIK, HB
AF SUNAHARA, RK
   GUAN, HC
   ODOWD, BF
   SEEMAN, P
   LAURIER, LG
   NG, G
   GEORGE, SR
   TORCHIA, J
   VANTOL, HHM
   NIZNIK, HB
TI CLONING OF THE GENE FOR A HUMAN DOPAMINE D5-RECEPTOR WITH HIGHER AFFINITY FOR DOPAMINE THAN D1
SO NATURE
LA English
DT Article
ID human-brain; receptors; schizophrenia; expression
AB DOPAMINE receptors belong to a superfamily of receptors that exert their biological effects through guanine nucleotide-binding (G) proteins. Two main dopamine receptor subtypes have been identified, D1 and D2, which differ in their pharmacological and biochemical characteristics. D1 stimulates adenylyl cyclase activity, whereas D2 inhibits it 1-3. Both receptors are primary targets for drugs used to treat many psychomotor diseases, including Parkinson's disease and schizophrenia 4,5. Whereas the dopamine D1 receptor has been cloned 6-9, biochemical and behavioural data indicate that dopamine D1-like receptors exist which either are not linked to adenylyl cyclase or display different pharmacological activities 10, 11. We report here the cloning of a gene encoding a 477-amino-acid protein with strong homology to the cloned D1 receptor. The receptor, called D5, binds drugs with a pharmacological profile similar to that of the cloned D1 receptor, but displays a 10-fold higher affinity for the endogenous agonist, dopamine. As with D1, the dopamine D5 receptor stimulates adenylyl cyclase activity. Northern blot and in situ hybridization analyses reveal that the receptor is neuron-specific, localized primarily within limbic regions of the brain; no messenger RNA was detected in kidney, liver, heart or parathyroid gland. The existence of a dopamine D1-like receptor with these characteristics had not been predicted and may represent an alternative pathway for dopamine-mediated events and regulation of D2 receptor activity 12-14.
C1 UNIV TORONTO, DEPT PSYCHIAT, TORONTO M5S 1A8, ONTARIO, CANADA.
   UNIV TORONTO, DEPT PHARMACOL, TORONTO M5S 1A8, ONTARIO, CANADA.
   ADDICT RES FDN, TORONTO M5S 2S1, ONTARIO, CANADA.
   CLARKE INST PSYCHIAT, MOLEC NEUROBIOL LAB, TORONTO M5T 1R8, ONTARIO, CANADA.
C3 University of Toronto; University of Toronto; University of Toronto; Centre for Addiction & Mental Health - Canada; University of Toronto; Centre for Addiction & Mental Health - Canada
NR 40
TC 1047
Z9 1180
U1 0
U2 30
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 614
EP 619
DI 10.1038/350614a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200061
PM 1826762
DA 2026-03-10
ER

PT J
AU CURRAH, RS
   STOCKEY, RA
AF CURRAH, RS
   STOCKEY, RA
TI A FOSSIL SMUT FUNGUS FROM THE ANTHERS OF AN EOCENE ANGIOSPERM
SO NATURE
LA English
DT Article
AB WHILE studying the floral morphology of a permineralized angiosperm from a Middle Eocene chert near Princeton, British Columbia, we encountered well-preserved masses of fungal spores in otherwise apparently normal anthers.  The spore masses, which replaced the pollen, consist of single-celled, irregularly shaped to ovoid, minutely pitted spores.  On the basis of intact nature of infected anthers and size, ornamentation and disposition of spores within anther locules, we have identified this material as an anthericolous smut fungus.  This unequivocal fossil of the Ustilaginales shows that at least 48 million years ago the order had representatives with anthericolous sori, a characteristic of some extant smut taxa that permits effective insect dispersal of the fungus among populations of specific host plants.
RP CURRAH, RS (corresponding author), UNIV ALBERTA,DEPT BOT,EDMONTON T6G 2E9,ALBERTA,CANADA.
NR 12
TC 13
Z9 16
U1 0
U2 7
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 698
EP 699
DI 10.1038/350698a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000057
DA 2026-03-10
ER

PT J
AU KAWABE, Y
   OCHI, A
AF KAWABE, Y
   OCHI, A
TI PROGRAMMED CELL-DEATH AND EXTRATHYMIC REDUCTION OF V-BETA-8+ CD4+ T-CELLS IN MICE TOLERANT TO STAPHYLOCOCCUS-AUREUS ENTEROTOXIN-B
SO NATURE
LA English
DT Article
ID major histocompatibility complex; transgenic mice; clonal-deletion; negative selection; antigen receptor; self-tolerance; mechanism; antibody
AB CLONAL deletion and functional inactivation of self-reactive cells have been invoked as mechanisms underlying intrathymic development of T-cell tolerance 1-10.  The relative importance of these mechanisms in the development of tolerance of more mature, peripheral T cells either to self or to exogenous antigens is unclear, although recent data relate the development of T-cell tolerance in the periphery to clonal anergy 11.  We have now investigated the induction of extrathymic tolerance using BALB/c mice that were made tolerant to Staphylococcus aureus enterotoxin B (ref. 12), a superantigen which specifically interacts in such mice with T cells bearing V-beta-8 antigen receptors 13-16.  Both euthymic and athymic mice made tolerant to S. aureus enterotoxin B had a markedly reduced number of V-beta-8.1,2+ CD4+ peripheral T cells.  This reduction was accompanied by genomic DNA fragmentation that is associated with cell death.  These results indicate that a deletional mechanism can contribute to the induction of T-cell tolerance in peripheral lymphoid cells.
C1 MT SINAI HOSP,SAMUEL LUNENFELD RES INST,DIV NEUROBIOL & MOLEC IMMUNOL,TORONTO M5G 1X5,ONTARIO,CANADA.
C3 University of Toronto; Sinai Health System Toronto; Lunenfeld Tanenbaum Research Institute
RP KAWABE, Y (corresponding author), UNIV TORONTO,DEPT IMMUNOL & MED GENET,TORONTO M5S 1A1,ONTARIO,CANADA.
NR 26
TC 734
Z9 795
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 245
EP 248
DI 10.1038/349245a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900058
PM 1670963
DA 2026-03-10
ER

PT J
AU SHEPPARD, WS
   RINDERER, TE
   MAZZOLI, JA
   STELZER, JA
   SHIMANUKI, H
AF SHEPPARD, WS
   RINDERER, TE
   MAZZOLI, JA
   STELZER, JA
   SHIMANUKI, H
TI GENE FLOW BETWEEN AFRICAN-DERIVED AND EUROPEAN-DERIVED HONEY-BEE POPULATIONS IN ARGENTINA
SO NATURE
LA English
DT Article
ID united-states; mitochondrial-dna; south-america; hybrid zones; behavior; history; races
AB IN the Neotropics, introduced European honey bees (Apis mellifera L.) 1,2 have been largely supplanted by bees descended from an African race, A. m. scutellata Lepetier, which were introduced into Brazil in the 1950s. Recent restriction enzyme analyses indicate that mitochondrial DNA in some neotropical populations is almost entirely of African origin 3,4, and these data have been cited as evidence for asymmetrical gene flow between African- and European-derived populations 3,4.  Evaluation of the nature of hybridization in the Neotropics is, however, confounded by possible population size advantages for the African-derived group 5-7. As an alternative approach, genetic interactions can be studied in transition areas between zones ecologically and climatically adaptive for both racial groups.  We describe here results of a survey transecting regions populated by African- and European-derived honey bees in Argentina.  Mitochondrial DNA, morphological and isoenzyme analyses show that substantial hybridization occurs between the two racial groups.
C1 USDA ARS,HONEY BEE BREEDING GENET & PHYSIOL RES LAB,BATON ROUGE,LA 70820.
   UNIV BUENOS AIRES,FAC AGRON,CATEDRA GENET,RA-1417 BUENOS AIRES,ARGENTINA.
C3 United States Department of Agriculture (USDA); University of Buenos Aires
RP SHEPPARD, WS (corresponding author), USDA ARS,BELTSVILLE AGR RES CTR,BEE RES LAB,BLDG 476,BARC-E,BELTSVILLE,MD 20705, USA.
NR 31
TC 143
Z9 151
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 782
EP 784
DI 10.1038/349782a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600053
DA 2026-03-10
ER

PT J
AU CHOPARD, B
   HERRMANN, HJ
   VICSEK, T
AF CHOPARD, B
   HERRMANN, HJ
   VICSEK, T
TI STRUCTURE AND GROWTH-MECHANISM OF MINERAL DENDRITES
SO NATURE
LA English
DT Article
ID patterns
AB THE surfaces of limestones are often marked by black or red-brown deposits known as mineral dendrites 1,2. These are deposits of hydrous iron or manganese oxides formed when supersaturated solutions of iron or manganese penetrate the limestone and are precipitated on exposure to air at the surface. Mineral dendrites have a fractal 3 appearance, but the origin and characteristics of this morphology, and its dependence on concentration gradients or reaction rates have been little studied. Here we analyse the shapes and fractal properties of mineral dendrites from several different origins, and propose a lattice reaction-diffusion model for their formation. The model shows how different reaction conditions can account for the variation in fractal dimension observed in real dendrites.
RP CHOPARD, B (corresponding author), FORSCHUNGSZENTRUM JULICH, HLRZ, POSTFACH 1913, W-5170 JULICH 1, GERMANY.
NR 10
TC 65
Z9 72
U1 2
U2 26
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 409
EP 412
DI 10.1038/353409a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600049
DA 2026-03-10
ER

PT J
AU OSANO, YT
   UCHIDA, A
   OHASHI, Y
AF OSANO, YT
   UCHIDA, A
   OHASHI, Y
TI OPTICAL ENRICHMENT OF A RACEMIC CHIRAL CRYSTAL BY X-RAY-IRRADIATION
SO NATURE
LA English
DT Article
ID c bond-cleavage; state
AB GENERATION of optical activity in a racemic mixture of enantiomers, a process relevant to (he origin of life and of naturally chiral compounds 1, requires chirality in the interaction responsible for the transformation or the environment in which it occurs. Without violating this strict requirement, we have found a way in which optical enrichment of a racemic mixture can occur without any chiral specificity in the mechanism. A racemic mixture of (1-cyanoethyl)(piperidine)cobaloxime, which contains the chiral 1-cyanoethyl group, crystallizes in a chiral space group (P2(1)2(1)2(1)) in which R and S enantiomers occupy crystallographically distinct (diastereoisomeric) positions in the asymmetric unit cell. We have prepared single crystals of the D configuration. Irradiating the crystal with X-rays at 343 K causes racemization of the S enantiomer while the R enantiomer remains unaltered. This racemization is thought to be due solely to the different volume constraints on the two enantiomers in their different crystal environments. The result is that the number of R molecules is increased at the expense of S, and so the overall composition of the crystal changes from racemic to enriched in the R enantiomer.
RP OSANO, YT (corresponding author), TOKYO INST TECHNOL,DEPT CHEM,2-12-1 OOKAYAMA,MEGURO KU,TOKYO 152,JAPAN.
NR 8
TC 33
Z9 33
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 510
EP 512
DI 10.1038/352510a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600055
DA 2026-03-10
ER

PT J
AU VANDERBLIEK, AM
   MEYEROWITZ, EM
AF VANDERBLIEK, AM
   MEYEROWITZ, EM
TI DYNAMIN-LIKE PROTEIN ENCODED BY THE DROSOPHILA-SHIBIRE GENE ASSOCIATED WITH VESICULAR TRAFFIC
SO NATURE
LA English
DT Article
ID temperature-sensitive mutant; mechanochemical enzyme; influenza-virus; melanogaster; microtubules; endocytosis; mutations; cloning; motor
AB TEMPERATURE-sensitive paralysis is the most striking defect of adult Drosophila carrying the shibire mutation 1.  This is believed to be due to a reversible block of endocytosis, which prevents membrane cycling and thus depletes synaptic vesicles 2, 3.  The shibire mutation also affects many tissues outside the nervous system 4-7.  We have now mapped and characterized the shibire gene.  A 275-kilobase yeast artificial chromosome was subcloned into cosmids, among which the gene was then located by analysing with restriction-fragment length polymorphisms.  A 15-kilobase fragment of wild-type DNA rescues the mutant phenotype and the sequence of two mutant alleles show differences with wild type, demonstrating that we have isolated the shibire gene.  The gene encodes a protein that is highly similar to rat dynamin 8, 9, 69% of the amino-acid sequence is identical.  Dynamin is a GTP-driven mechanochemical enzyme related to mammalian mx-proteins 10 and  to the yeast vps 1 gene product 11.  Because the shibire gene product and dynamin have extensive similarity, we propose that they are cognate homologues.  Dynamin causes microtubules to slide along each other in vitro 12 and in extracts it is associated with a distinct, but so far uncharacterized, membrane fraction 13.  In light of the shibire phenotype, we suggest that these proteins provide the motor for vesicular transport during endocytosis.
RP VANDERBLIEK, AM (corresponding author), CALTECH,DIV BIOL 15629,PASADENA,CA 91125, USA.
NR 26
TC 659
Z9 746
U1 0
U2 51
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 411
EP 414
DI 10.1038/351411a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600060
PM 1674590
DA 2026-03-10
ER

PT J
AU WALSH, J
   WATTERSON, J
   YIELDING, G
AF WALSH, J
   WATTERSON, J
   YIELDING, G
TI THE IMPORTANCE OF SMALL-SCALE FAULTING IN REGIONAL EXTENSION
SO NATURE
LA English
DT Article
ID deformation
AB A RECURRING observation in many studies of extensional basins has been that the amount of extension visible on normal faults (for example, on seismic reflection profiles) is significantly less than the amount of extension indicated by crustal thickness and thermal subsidence 1-5. One mechanism suggested to account for this discrepancy is small-scale faulting, with offsets too small to be resolved seismically 6,7.  But earthquake studies 8-10 indicate that small faults are responsible for only a small fraction of the total seismic moment in an active area. Scholz and Cowie 11 have recently attempted to extend this approach to the total strain at the end of a finite deformation interval by combining scaling laws describing the distributions of fault lengths and displacements.  Here we present fault displacement data that directly conflict with Scholz and Cowie's conclusions, and imply that up to 40% of the extension may be missed by summing fault offsets on basin profiles.  The fault population at the end of a long deformation interval may differ substantially from that responsible for the earthquake population at any one time.
C1 BADLEY ASHTON & ASSOCIATES LTD,HORNCASTLE LN9 6PB,LINCS,ENGLAND.
RP WALSH, J (corresponding author), UNIV LIVERPOOL,DEPT EARTH SCI,FAULT ANAL GRP,POB 147,LIVERPOOL L69 3BX,ENGLAND.
NR 24
TC 209
Z9 237
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 391
EP 393
DI 10.1038/351391a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600053
DA 2026-03-10
ER

PT J
AU WOODLAND, DL
   HAPP, MP
   GOLLOB, KJ
   PALMER, E
AF WOODLAND, DL
   HAPP, MP
   GOLLOB, KJ
   PALMER, E
TI AN ENDOGENOUS RETROVIRUS MEDIATING DELETION OF ALPHA-BETA T-CELLS
SO NATURE
LA English
DT Article
ID major histocompatibility complex; monoclonal-antibody; imparts reactivity; i-e; tolerance; differentiation; expression; antigens; transcripts; molecule
AB A SPECIAL class of self-antigens (endogenous superantigens) is capable of deleting many murine T cells on the basis of their expression of particular T-cell receptor V-beta gene segments. In mice that endogenously express these antigens, tolerance is mediated in part by the clonal deletion of the relevant V-beta-bearing T cells 1-17. The deletion of I-E-reactive V-beta-5.2-bearing T cells is dependent on the coexpression of an I-E tolerogenic coligand (Etc) 14 and the gene for one of these coligands, Etc-1, maps to chromosome 12, near the mouse mammary tumour viral integrant, Mtv-9. Here we report a perfect genetic linkage between Etc-1 and Mtv-9 and show that Etc-1 is also involved in the I-E-dependent deletion of T cells bearing V-beta-5.1 and V-beta-11 domains. We also demonstrate that Mtv-9 transcripts are present in B cells expressing Etc-1 and suggest that the coligand recognized by roughly 15% of all T lymphocytes is encoded by the Mtv-9 genome.
C1 NATL JEWISH CTR IMMUNOL & RESP MED, DEPT PEDIAT, DIV BASIC SCI, DENVER, CO 80206 USA.
   UNIV COLORADO, HLTH SCI CTR, DEPT MICROBIOL & IMMUNOL, DENVER, CO 80262 USA.
C3 National Jewish Health; University of Colorado System; University of Colorado Anschutz Medical Campus; University of Colorado Denver
RP WOODLAND, DL (corresponding author), ST JUDE CHILDRENS RES HOSP, DEPT IMMUNOL, 332 N LAUDERDALE, MEMPHIS, TN 38105 USA.
NR 30
TC 319
Z9 330
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 529
EP 530
DI 10.1038/349529a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100068
PM 1846949
DA 2026-03-10
ER

PT J
AU HOLBROOK, SR
   CHEONG, CJ
   TINOCO, I
   KIM, SH
AF HOLBROOK, SR
   CHEONG, CJ
   TINOCO, I
   KIM, SH
TI CRYSTAL-STRUCTURE OF AN RNA DOUBLE HELIX INCORPORATING A TRACK OF NON-WATSON-CRICK BASE-PAIRS
SO NATURE
LA English
DT Article
ID dna; mismatches
AB THE crystal structure of the RNA dodecamer duplex (r-GGACUUCGGUCC)2 has been determined.  The dodecamers stack end-to-end in the crystal, simulating infinite A-form helices with only a break in the phosphodiester chain.  These infinite helices are held together in the crystal by hydrogen bonding between ribose hydroxyl groups and a variety of donors and acceptors.  The four noncomplementary nucleotides in the middle of the sequence did not form an internal loop, but rather a highly regular double-helix incorporating the non-Watson-Crick base pairs, G . U and U . C.  This is the first direct observation of a U . C (or T . C) base pair in a crystal structure.  The U . C pairs each form only a single base-base hydrogen bond, but are stabilized by a water molecule which bridges between the ring nitrogens and by four waters in the major groove which link the bases and phosphates.  The lack of distortion introduced in the double helix by the U . C mismatch may explain its low efficiency of repair in DNA.  The G . U wobble pair is also stabilized by a minor-groove water which bridges between the unpaired guanine amino and the ribose hydroxyl of the uracil.  This structure emphasizes the importance of specific hydrogen bonding between not only the nucleotide bases, but also the ribose hydroxyls, phosphate oxygens and tightly bound waters in stabilization of the intramolecular and intermolecular structures of double helical RNA.
C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720.
C3 University of California System; University of California Berkeley
RP HOLBROOK, SR (corresponding author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA.
NR 18
TC 325
Z9 347
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 579
EP 581
DI 10.1038/353579a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300075
PM 1922368
DA 2026-03-10
ER

PT J
AU NATSOULIS, G
   BOEKE, JD
AF NATSOULIS, G
   BOEKE, JD
TI NEW ANTIVIRAL STRATEGY USING CAPSID NUCLEASE FUSION PROTEINS
SO NATURE
LA English
DT Article
ID virus-like particles; saccharomyces-cerevisiae; staphylococcal nuclease; element transposition; reverse-transcriptase; ty1 transposition; yeast; gene; ribonuclease; expression
AB OVEREXPRESSION of dominant-negative mutants of various viral proteins can result in 'intracellular immunization' (refs 1, 2). Here we describe a new approach to interfering with viral replication in which a nuclease is fused to a capsid component so that the nuclease is encapsidated inside the virion where it can inactivate viral nucleic acid. We used Ty1, a yeast retrotransposon whose transposition closely parallels retroviral replication mechanisms and serves as an easily manipulated model for the retroviral infection process 3. We constructed fusion genes consisting of the region encoding the N-terminal portion of the TYA/TYB open reading frames of retrotransposon Ty1 and either of two different nuclease genes. Ty1-nuclease fusion proteins are targeted to Ty1 virus-like particles, and are active in degrading nucleic acids. A Ty1-barnase fusion protein causes 98-99% reduction in the efficiency of Ty1 transposition in vivo, presumably by degrading encapsidated Ty1 RNA. This strategy, referred to as capsid-targeted viral inactivation, may be useful for interfering with the replication of retroviruses and other viruses.
RP NATSOULIS, G (corresponding author), JOHNS HOPKINS UNIV,SCH MED,DEPT MOLEC BIOL & GENET,725 N WOLFE ST,BALTIMORE,MD 21205, USA.
NR 29
TC 62
Z9 86
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 632
EP 635
DI 10.1038/352632a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100059
PM 1650915
DA 2026-03-10
ER

PT J
AU SPAINK, HP
   SHEELEY, DM
   VANBRUSSEL, AAN
   GLUSHKA, J
   YORK, WS
   TAK, T
   GEIGER, O
   KENNEDY, EP
   REINHOLD, VN
   LUGTENBERG, BJJ
AF SPAINK, HP
   SHEELEY, DM
   VANBRUSSEL, AAN
   GLUSHKA, J
   YORK, WS
   TAK, T
   GEIGER, O
   KENNEDY, EP
   REINHOLD, VN
   LUGTENBERG, BJJ
TI A NOVEL HIGHLY UNSATURATED FATTY-ACID MOIETY OF LIPO-OLIGOSACCHARIDE SIGNALS DETERMINES HOST SPECIFICITY OF RHIZOBIUM
SO NATURE
LA English
DT Article
ID leguminosarum bv viciae; sym plasmid prl1ji; root exudate; nodulation region; nod gene; meliloti; protein; encodes; nodules; mutants
AB In Rhizobium leguminosarum biovar viciae, the nodABC and nodFEL operons are involved in the production of lipo-oligosaccharide signals which mediate host specificity. The structure of these metabolites and those produced in nod mutants links the nodE and nodL genes to specific chemical features of the signal molecules. A nodE-determined, highly unsaturated fatty acid and a nodL-determined O-acetyl substituent are essential for the ability of the signals to induce nodule meristems on the host plant Vicia sativa.
C1 HARVARD UNIV,SCH PUBL HLTH,DEPT NUTR,BOSTON,MA 02115.
   COMPLEX CARBOHYDRATE RES CTR,ATHENS,GA 30602.
   HARVARD UNIV,SCH MED,DEPT BIOL CHEM & MOLEC PHARMACOL,BOSTON,MA 02115.
C3 Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard Medical School
RP SPAINK, HP (corresponding author), LEIDEN UNIV,DEPT PLANT MOLEC BIOL,NONNENST 3,2311 VJ LEIDEN,NETHERLANDS.
NR 34
TC 457
Z9 485
U1 0
U2 42
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 125
EP 130
DI 10.1038/354125a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000051
PM 1944592
DA 2026-03-10
ER

PT J
AU CRAMER, SM
AF CRAMER, SM
TI DISPLACEMENT CHROMATOGRAPHY
SO NATURE
LA English
DT Article
ID performance liquid-chromatography; operating parameters; ion-exchange; proteins; separations; biomolecules; derivatives; adsorption; reactor; model
RP CRAMER, SM (corresponding author), RENSSELAER POLYTECH INST,DEPT CHEM ENGN,TROY,NY 12180, USA.
NR 33
TC 15
Z9 15
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 251
EP 252
DI 10.1038/351251a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000063
DA 2026-03-10
ER

PT J
AU LAZARD, D
   ZUPKO, K
   PORIA, Y
   NEF, P
   LAZAROVITS, J
   HORN, S
   KHEN, M
   LANCET, D
AF LAZARD, D
   ZUPKO, K
   PORIA, Y
   NEF, P
   LAZAROVITS, J
   HORN, S
   KHEN, M
   LANCET, D
TI ODORANT SIGNAL TERMINATION BY OLFACTORY UDP GLUCURONOSYL TRANSFERASE
SO NATURE
LA English
DT Article
ID sensitive adenylate-cyclase; rat; cytochrome-p-450; assay; identification; purification; localization; stimulation; epithelium; reception
AB THE onset of olfactory transduction has been extensively studied 1-7, but considerably less is known about the molecular basis of olfactory signal termination 6,8,9.  It has been suggested that the highly active cytochrome P450 monooxygenases of olfactory neuroepithelium 10-12 are termination enzymes 5,8,11,12, a notion supported by the identification and molecular cloning of olfactory-specific cytochrome P450s (refs. 13-16).  But as reactions catalysed by cytochrome P450 (refs 17, 18) often do not significantly alter volatility, lipophilicity or odour properties 9,11, cytochrome P450 may not be solely responsible for olfactory signal termination.  In liver and other tissues, drug hydroxylation by cytochrome P450 is frequently followed by phase II biotransformation, for example by UDP glucuronosyl transferase (UGT), resulting in a major change of solubility and chemical properties 19. We report here the molecular cloning and expression of an olfactory-specific UGT.  The olfactory enzyme, but not the one in liver microsomes, shows preference for odorants over standard UGT substrates. Furthermore, glucuronic acid conjugation abolishes the ability of odorants 1,20 to stimulate olfactory adenylyl cyclase.  This, together with the known broad spectrum of drug-detoxification enzymes 17,19, supports a role for olfactory UGT in terminating diverse odorant signals.
C1 WEIZMANN INST SCI,DEPT MEMBRANE RES,IL-76100 REHOVOT,ISRAEL.
C3 Weizmann Institute of Science
NR 38
TC 205
Z9 210
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 790
EP 793
DI 10.1038/349790a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600056
PM 1900353
DA 2026-03-10
ER

PT J
AU ZINNER, E
   AMARI, S
   ANDERS, E
   LEWIS, R
AF ZINNER, E
   AMARI, S
   ANDERS, E
   LEWIS, R
TI LARGE AMOUNTS OF EXTINCT AL-26 IN INTERSTELLAR GRAINS FROM THE MURCHISON METEORITE
SO NATURE
LA English
DT Article
ID anomaly
AB INTERSTELLAR graphite and silicon carbide grains recovered from the Murchison CM2 chondritic meteorite are known to show large anomalies in the isotopic abundances of neon, xenon, carbon, nitrogen and silicon1-3. These anomalies provide clues to the nucleosynthetic origin of the material from which the grains formed.  Here we report that both types of grain also have large abundances of Mg-26 from the decay of extinct Al-26 (half-life 705,000 years).  The deduced initial Al-26/Al-27 ratios range up to 0.06 in graphite and 0.2 in SiC-1,200 and 4,000 times the maximum values found in refractory inclusions in primitive meteorites. All proposed stellar sources of carbonaceous dust (red giants, novae, Wolf-Rayet stars and supernovae) also produce Al-26, but the highest Al-26/Al-27 ratios found in these grains seem to rule out Wolf-Rayet stars and supernovae.  The aluminium abundance correlates with that of nitrogen, suggesting that the aluminium condensed as aluminium nitride.
C1 WASHINGTON UNIV,DEPT PHYS,ST LOUIS,MO 63130.
   UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637.
   UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637.
C3 Washington University (WUSTL); University of Chicago; University of Chicago
RP ZINNER, E (corresponding author), WASHINGTON UNIV,MCDONNELL CTR SPACE SCI,ST LOUIS,MO 63130, USA.
NR 27
TC 85
Z9 90
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 51
EP 54
DI 10.1038/349051a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100046
DA 2026-03-10
ER

PT J
AU ASADA, T
   SONOBE, S
   SHIBAOKA, H
AF ASADA, T
   SONOBE, S
   SHIBAOKA, H
TI MICROTUBULE TRANSLOCATION IN THE CYTOKINETIC APPARATUS OF CULTURED TOBACCO CELLS
SO NATURE
LA English
DT Article
ID invitro
AB IN higher plant cells, cytokinesis is achieved by new cross-wall formation mediated by the phragmoplast 1, a double ring of microtubules of opposite polarity, in which the short microtubules are arranged perpendicular to the equatorial plane of the phragmoplast with their plus ends interdigitating at the plane 1,2.  The phragmoplast and its enclosed cell plate move out centrifugally until the mother cell divides.  We report here results of a newly developed method using glycerinated cultured tobacco cells, which show that the equatorial region of the phragmoplast can translocate microtubules toward their minus ends concomitantly with tubulin polymerization at their plus ends. The translocation is induced effectively by GTP and less effectively by ATP, and is inhibited by the unhydrolysable nucleotide analogues GMP-PNP and AMP-PNP.  Thus, the equatorial region of the phragmoplast seems to be associated with a mechanochemical enzyme that generates the force for microtubule translocation by hydrolysing GTP.
RP ASADA, T (corresponding author), OSAKA UNIV,FAC SCI,DEPT BIOL,TOYONAKA,OSAKA 560,JAPAN.
NR 10
TC 110
Z9 116
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 238
EP 241
DI 10.1038/350238a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900060
DA 2026-03-10
ER

PT J
AU ISHIJIMA, A
   DOI, T
   SAKURADA, K
   YANAGIDA, T
AF ISHIJIMA, A
   DOI, T
   SAKURADA, K
   YANAGIDA, T
TI SUB-PICONEWTON FORCE FLUCTUATIONS OF ACTOMYOSIN INVITRO
SO NATURE
LA English
DT Article
ID single kinesin molecules; actin-filaments; muscle-contraction; sliding filaments; myosin; movement; mechanism; motion; direction; velocity
AB A new system has been developed for measuring the forces produced by a small number (< 5-150) of myosin molecules interacting with a single actin filament in vitro. The technique can resolve forces of less than a piconewton and has a time resolution in the submillisecond range. It can thus detect fluctuations of force caused by individual molecular interactions. From analysis of these force fluctuations, the coupling between the enzymatic ATPase activity of actomyosin and the resulting mechanical impulses can be elucidated.
C1 OSAKA UNIV,DEPT BIOPHYS ENGN,TOYONAKA,OSAKA 560,JAPAN.
   HONDA RES & DEV CO,WAKO RES CTR,WAKO,SAITAMA,JAPAN.
C3 University of Osaka; Honda Motor Company
NR 49
TC 234
Z9 241
U1 1
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 301
EP 306
DI 10.1038/352301a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900059
PM 1830130
DA 2026-03-10
ER

PT J
AU SPADA, G
   YUEN, DA
   SABADINI, R
   BOSCHI, E
AF SPADA, G
   YUEN, DA
   SABADINI, R
   BOSCHI, E
TI LOWER-MANTLE VISCOSITY CONSTRAINED BY SEISMICITY AROUND DEGLACIATED REGIONS
SO NATURE
LA English
DT Article
ID cycle
AB KNOWLEDGE of the viscosity structure of the Earth's mantle is important for constraining models of mantle convection and isostatic rebound.  Here we show that seismicity around the margins of deglaciated areas provides a constraint on the viscosity of the lower mantle, in addition to those previously proposed 1,2.  Calculations using a spherical, viscoelastic Earth model show that the present-day magnitude of the stress fields induced in the lithosphere beneath the (now-disappeared) Laurentide and Fennoscandian ice sheets is very sensitive to the value of the lower-mantle viscosity.  Stresses of approximately 100 bar, sufficient to cause seismicity, can still remain in the lithosphere for lower-mantle viscosities greater than approximately 10(22) Pa s; for lower-mantle viscosities of approximately 10(21) Pa s, only a few tens of bars of stress persist in the lithosphere today.  This influence of lower-mantle viscosity on the state of stress in the lithosphere also has implications for the migration of stress from earthquakes, and hence for earthquake recurrence times.
C1 UNIV MINNESOTA,DEPT GEOL & GEOPHYS,MINNEAPOLIS,MN 55415.
   UNIV MINNESOTA,MINNESOTA SUPERCOMP INST,MINNEAPOLIS,MN 55415.
C3 University of Minnesota System; University of Minnesota Twin Cities; University of Minnesota System; University of Minnesota Twin Cities
RP SPADA, G (corresponding author), UNIV BOLOGNA,DIPARTMENTO FIS,IST GEOFIS,I-40127 BOLOGNA,ITALY.
NR 19
TC 36
Z9 37
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 53
EP 55
DI 10.1038/351053a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300056
DA 2026-03-10
ER

PT J
AU KOKUFATA, E
   ZHANG, YQ
   TANAKA, T
AF KOKUFATA, E
   ZHANG, YQ
   TANAKA, T
TI SACCHARIDE-SENSITIVE PHASE-TRANSITION OF A LECTIN-LOADED GEL
SO NATURE
LA English
DT Article
ID ionic gels; collapse
AB A GEL system that swells and shrinks in response to specific molecules could serve as the basis for technological applications of polymer gels, for example as sensors, drug-delivery devices and actuators.  Here we describe a lectin-loaded polymer gel that undergoes distinct swelling behaviour in response to different saccharides.  The gel consists of a covalently cross-linked polymer network of N-isopropylacrylamide in which the lectin, concanavalin A, is immobilized.  Concanavalin A displays selective binding affinities for certain saccharides.  The gel undergoes a volume phase transition at approximately 34-degrees-C.  When the saccharide dextran sulphate is added (as the sodium salt DSS) to the gel, it swells to a volume up to five times greater at temperatures close to this transition, and the transition itself changes from discontinuous to continuous.  Replacing DSS with the non-ionic saccharide alpha-methyl-D-mannopyranoside brings about collapse of the gel back to almost its native volume.  This process is reversible and repeatable.  These results point to a general principle for the design of such molecule-specific systems.
C1 UNIV TSUKUBA,INST APPL BIOCHEM,SAKURA,IBARAKI 305,JAPAN.
   MIT,CTR MAT SCI & ENGN,CAMBRIDGE,MA 02139.
C3 University of Tsukuba; Massachusetts Institute of Technology (MIT)
RP KOKUFATA, E (corresponding author), MIT,DEPT PHYS,CAMBRIDGE,MA 02139, USA.
NR 13
TC 207
Z9 223
U1 0
U2 40
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 302
EP 304
DI 10.1038/351302a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600054
DA 2026-03-10
ER

PT J
AU FALLON, AM
AF FALLON, AM
TI DNA-MEDIATED GENE-TRANSFER - APPLICATIONS TO MOSQUITOS
SO NATURE
LA English
DT Article
ID aedes-albopictus cells; anopheles-gambiae; transient expression; integration; drosophila; vector
RP FALLON, AM (corresponding author), UNIV MINNESOTA,ENTOMOL,1980 FOLWELL AVE,ST PAUL,MN 55108, USA.
NR 21
TC 17
Z9 18
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 828
EP 829
DI 10.1038/352828a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400068
PM 1679196
DA 2026-03-10
ER

PT J
AU RUPPERSBERG, JP
   STOCKER, M
   PONGS, O
   HEINEMANN, SH
   FRANK, R
   KOENEN, M
AF RUPPERSBERG, JP
   STOCKER, M
   PONGS, O
   HEINEMANN, SH
   FRANK, R
   KOENEN, M
TI REGULATION OF FAST INACTIVATION OF CLONED MAMMALIAN IK(A) CHANNELS BY CYSTEINE OXIDATION
SO NATURE
LA English
DT Article
ID delayed rectifier property; brain potassium-channel; rat-brain; expression; cloning; family; aplysia; member; cdna
AB MODULATION of neuronal excitability by regulation of K+ channels potentially plays a part in short-term memory 1 but has not yet been studied at the molecular level. Regulation of K+ channels by protein phosphorylation 2-5 and oxygen 6 has been described for various tissues and cell types; regulation of fast-inactivating K+ channels mediating I(K)(A) currents has not yet been described. Functional expression of cloned mammalian K+ channels 7-13 has provided a tool for studying their regulation at the molecular level. We report here that fast-inactivating K+ currents mediated by cloned K+ channel subunits derived from mammalian brain expressed in Xenopus oocytes are regulated by the reducing agent glutathione. This type of regulation may have a role in vivo to link metabolism to excitability and to regulate excitability in specific membrane areas of mammalian neurons.
C1 MAX PLANCK INST BIOPHYS CHEM, MEMBRANBIOPHYS ABT, W-3400 GOTTINGEN, GERMANY.
   ZENTRUM MOLEK BIOL, W-6900 HEIDELBERG, GERMANY.
   RUHR UNIV BOCHUM, LEHRSTUHL BIOCHEM, W-4600 BOCHUM, GERMANY.
C3 Max Planck Society; Ruprecht Karls University Heidelberg; Ruhr University Bochum
RP RUPPERSBERG, JP (corresponding author), MAX PLANCK INST MED RES, ZELLPHYSIOL ABT, JAHNSTR 29, W-6900 HEIDELBERG 1, GERMANY.
NR 25
TC 451
Z9 473
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 711
EP 714
DI 10.1038/352711a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400057
PM 1908562
DA 2026-03-10
ER

PT J
AU ELLIOTT, T
   CERUNDOLO, V
   ELVIN, J
   TOWNSEND, A
AF ELLIOTT, T
   CERUNDOLO, V
   ELVIN, J
   TOWNSEND, A
TI PEPTIDE-INDUCED CONFORMATIONAL CHANGE OF THE CLASS-I HEAVY-CHAIN
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; influenza-a virus; hla-b antigens; surface expression; synthetic peptides; viral peptides; nucleoprotein; molecules; beta-2-microglobulin; invitro
AB THERE is evidence that peptide ligands take part in the assembly of class I molecules 1-8.  In particular, addition of peptides to extracts of the mutant cells RMA-S and .174/T2, in which stable assembly of class I does not occur 9-11, results in a conformational change in the class I heavy chain and stable association of the heavy chain with beta-2-microglobulin (beta-2m) (refs 1-3).  Thus specific peptides may stabilize or induce a conformational change in the class I heavy chain that results in a rise in the binding affinity of the heavy chain for beta-2m (Fig. 1a).  Here we show that peptides have two cooperative roles in class I assembly.  Specific short peptides (9-10 amino acids) can induce folding of the heavy chain in  the absence of beta-2m.  Both short (nine amino acids) and longer  sequences (15 amino acids) can stabilize performed low-affinity complexes of heavy chain and beta-2m.  To alter the conformation of free heavy chains, the peptides must be exactly the correct size, and they are found to correspond to the sequences isolated from infected cells 12.  This property may therefore be the basis for selection of epitopes presented in vivo.
RP ELLIOTT, T (corresponding author), JOHN RADCLIFFE HOSP,INST MOLEC MED,OXFORD OX3 9DU,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 19
TC 250
Z9 272
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 402
EP 406
DI 10.1038/351402a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600057
PM 2034289
DA 2026-03-10
ER

PT J
AU SILVER, ML
   PARKER, KC
   WILEY, DC
AF SILVER, ML
   PARKER, KC
   WILEY, DC
TI RECONSTITUTION BY MHC-RESTRICTED PEPTIDES OF HLA-A2 HEAVY-CHAIN WITH BETA-2-MICROGLOBULIN, INVITRO
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; histocompatibility antigens; association; molecules; epitopes; binding
AB CYTOTOXIC T lymphocytes kill virally infected cells when they detect antigenic fragments presented by class I major histocompatibility complex (MHC) antigens (HLA in humans).  The crystal structures of HLA-A2 and HLA-Aw68 reveal that peptide-antigen forms an integral part of the HLA structure, being retained in a prominent groove even after purification and crystallization 1-3.  Here we report that the heavy chain and beta-2-microglobulin of HLA-A2, after separation and fractionation in denaturants, reassemble efficiently under renaturing conditions only in the presence of MHC-restricted 4 peptides.  A complex of heavy chain, beta-2-microglobulin, and viral peptide in the ratio 1:1:1 is formed in up to 46% yield.  Reconstitution is not stimulated by either of two peptides not restricted to HLA-A2.  The reconstituted complex of HLA-A2 and the influenza virus (B/Lee/40) nucleoprotein peptide, Np (85-94), crystallizes under conditions previously used to crystallize HLA-A2 (ref. 5).  Peptide-linked folding and assembly suggests mechanisms for the unusual capacity of HLA to bind many peptides of diverse sequence.
C1 HARVARD UNIV,HOWARD HUGHES MED INST,7 DIVIN AVE,CAMBRIDGE,MA 02138.
   HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,CAMBRIDGE,MA 02138.
C3 Howard Hughes Medical Institute; Harvard University; Harvard University
NR 24
TC 110
Z9 121
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 619
EP 622
DI 10.1038/350619a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200062
PM 2017257
DA 2026-03-10
ER

PT J
AU BENKMAN, CW
   LINDHOLM, AK
AF BENKMAN, CW
   LINDHOLM, AK
TI THE ADVANTAGES AND EVOLUTION OF A MORPHOLOGICAL NOVELTY
SO NATURE
LA English
DT Article
ID food profitability; foraging behavior; crossbills; ecology
AB THE role of selective agents in the origin of evolutionary novelties has been controversial 1-3 and has remained outside the realm of experiments. Here we experimentally determine both the benefits of a single trait and the advantages accrued during the presumed sequenced of evolutionary steps leading to the fully specialized structure. By comparison of red crossbills (Loxia curvirostra, L.), in which the mandibular crossing has been removed, with controls and with the related but less specialized pine siskin (Carduelis pinus Wilson), we show the advantage of the mandibular crossing in the extraction of seeds from partially closed conifer cones. We use the natural regrowth of the mandibles to mimic the evolution of mandibular crossing from an unspecialized ancestor, and use the relationship of foraging efficiency to mandibular regrowth to determine a scheme for its (gradual) evolution.
RP BENKMAN, CW (corresponding author), UNIV BRITISH COLUMBIA, DEPT ZOOL, VANCOUVER V6T 2A9, BC, CANADA.
NR 23
TC 64
Z9 72
U1 0
U2 23
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 519
EP 520
DI 10.1038/349519a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100064
DA 2026-03-10
ER

PT J
AU NEININGER, N
   KLEIN, U
   BECK, R
   WIELEBINSKI, R
AF NEININGER, N
   KLEIN, U
   BECK, R
   WIELEBINSKI, R
TI CORRELATION OF MAGNETIC AND OPTICAL STRUCTURE IN THE BARRED SPIRAL GALAXY M83
SO NATURE
LA English
DT Article
ID radio-continuum observations
AB THE barred spiral (SBc) galaxy M83 was previously studied thoroughly in the optical regime 1-3, and is known to possess an ordered magnetic field, with radio emission showing linear polarization of up to 60% in the outer regions 4-6.  Earlier radio studies were done at lower frequencies, where Faraday rotation of the polarization by the magnetic field is important, but we have now observed M83 using the 100-m Effelsberg telescope at a frequency of 10.6 GHz, at which Faraday rotation should be less than 1-degrees.  There is significant polarization in the inner part of the galaxy, where we find that the magnetic field closely follows the optical structure.  We see some deviations from the ordered magnetic structure that coincide with optical patchiness, and two pronounced polarization minima that correspond with enhancements of CO emission 7.  Our results suggest that the inner structure of the galaxy is more orderly than earlier work 6 had indicated, and that any gross disorder, perhaps due to star formation, occurs only in the innermost regions.  In addition, the observed distribution of Faraday rotation across the galaxy, deduced from comparison of observations at different frequencies, provides evidence that a significant component of the magnetic field extends away from the disk.
RP NEININGER, N (corresponding author), MAX PLANCK INST RADIOASTRON,HUGEL 69,W-5300 BONN 1,GERMANY.
NR 15
TC 36
Z9 36
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 781
EP 783
DI 10.1038/352781a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400050
DA 2026-03-10
ER

PT J
AU GOMEZ, N
   COHEN, P
AF GOMEZ, N
   COHEN, P
TI DISSECTION OF THE PROTEIN-KINASE CASCADE BY WHICH NERVE GROWTH-FACTOR ACTIVATES MAP KINASES
SO NATURE
LA English
DT Article
ID myelin basic-protein; okadaic acid; phosphorylation; insulin; cells; identification; phosphatase-2a; line
AB MITOGEN activated protein (MAP) kinases (MAPKs) are a family of protein-serine/threonine kinases activated as an early intracellular response to a variety of hormones and growth factors 1-4.  They are unique in requiring both serine/threonine and tyrosine phosphorylation to become active 5 and are the only examples of protein-serine/threonine kinases activated by tyrosine phosphorylation. Nerve growth factor (NGF) promotes differentiation of phaeochromocytoma (PC12) cells, which respond by conversion within hours from a chromaffin-like to a sympathetic neuron-like phenotype 6,7.  NGF stimulation of PC12 cells increases the activity of two protein kinases by > 20-fold within minutes 8, both strikingly similar to MAPKs. They are inactivated by either protein-tyrosine phosphatases or the protein-serine/threonine phosphatase termed protein phosphatase 2A (ref. 8), they activate protein S6 kinase-II (refs 9, 10), and they phosphorylate identical threonine residues on myelin basic protein (our unpublished results) to those phosphorylated by other MAPKs 11,12.  Immunological data 13 indicate that these protein kinases, termed peak-I and peak-II (Fig. 1a) are probably ERK2 and ERK1, respectively, two widely expressed MAPK isoforms 13.  Here we identify the 'MAP kinase kinases' (MAPKKs) in PC12 cells which are activated by NGF and report that MAPKKs are dependent on serine/threonine phosphorylation for activity and promote phosphorylation of serine/threonine and tyrosine residues on MAPKs.
RP GOMEZ, N (corresponding author), UNIV DUNDEE,DEPT BIOCHEM,MRC,PROT PHOSPHORYLAT UNIT,DUNDEE DD1 4HN,SCOTLAND.
NR 30
TC 571
Z9 604
U1 0
U2 17
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 170
EP 173
DI 10.1038/353170a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100055
PM 1716348
DA 2026-03-10
ER

PT J
AU AREF, H
   ZAWADZKI, I
AF AREF, H
   ZAWADZKI, I
TI LINKING OF VORTEX RINGS
SO NATURE
LA English
DT Article
ID cross-linking; reconnection
AB THE topology of vortex lines, which trace the local vorticity in a fluid flow just as streamlines trace the velocity, is important in attempts to understand, describe and control flows in various applications. Changes in this topology may, for example, affect mixing in flows, and may be significant for the dynamics of turbulence. In particular, the behaviour of closed loops of vortex lines (vortex rings) has been studied ever since Kelvin's 'vortex atom' theory, and contributed to Tait's development of the topological theory of knots. Several recent experimental and computational studies 1-9 have explored the 'reconnection' of initially distinct vortex rings; particularly elegant are Schatzle's 10 experiments in which two vortex rings, inclined towards one another, go through two reconnections, after which two new rings, comprising half of each of the originals, emerge. Here we describe three-dimensional numerical simulations which establish a simple mechanism by which the linking of two vortex rings may be achieved starting from an unlinked initial state. Appropriate initial states were identified by simulating the unlinking of two initially linked vortex rings and then reversing the vorticity of the final state and running the simulation backwards. This computational procedure sheds light on why, both in experiment and simulation, linking is not always achieved from an arbitrary initial configuration of unlinked vortex rings set on a collision course.
RP AREF, H (corresponding author), UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093, USA.
NR 20
TC 61
Z9 63
U1 0
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 50
EP 53
DI 10.1038/354050a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900053
DA 2026-03-10
ER

PT J
AU MELOSH, HJ
   VICKERY, AM
AF MELOSH, HJ
   VICKERY, AM
TI MELT DROPLET FORMATION IN ENERGETIC IMPACT EVENTS
SO NATURE
LA English
DT Article
ID cretaceous-tertiary boundary; spherules; origin
AB IT has long been known that impact between rocky bodies at velocities of greater-than-or-similar-to 15 km s-1 can melt or vaporize both the impacting object and a portion of the target 1.  We have recently shown 2,3 that geological materials initially shocked to high pressure approach the liquid-vapour phase boundary from the liquid side as they decompress, breaking up into an expanding spray of liquid droplets. Here we present a simple theory for estimating the sizes of these droplets as a function of impactor size and velocity, and show that these sizes are consistent with observations of microtektites and spherules found in the Cretaceous/Tertiary boundary layer.
RP MELOSH, HJ (corresponding author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA.
NR 24
TC 117
Z9 127
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 494
EP 497
DI 10.1038/350494a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300048
DA 2026-03-10
ER

PT J
AU HORVITZ, HR
   STERNBERG, PW
AF HORVITZ, HR
   STERNBERG, PW
TI MULTIPLE INTERCELLULAR SIGNALING SYSTEMS CONTROL THE DEVELOPMENT OF THE CAENORHABDITIS-ELEGANS VULVA
SO NATURE
LA English
DT Article
ID specifies cell fates; egf receptor homolog; faint-little-ball; c-elegans; embryonic-development; lateral inhibition; drosophila-notch; genetic pathway; tyrosine kinase; nervous-system
AB Developmental, genetic and molecular studies indicate that multiple intercellular signalling systems interact to specify the types and spatial patterns of cells generated during the formation of the vulva of the nematode Caenorhabditis elegans.  Two classes of evolutionarily conserved transmembrane receptors and a Ras protein function in these signalling systems.  The biology of vulval development provides a framework for understanding how cell interactions control the development of animals as diverse as nematodes, insects and mammals.
C1 CALTECH,HOWARD HUGHES MED INST,DIV BIOL,PASADENA,CA 91125.
C3 California Institute of Technology; Howard Hughes Medical Institute
RP HORVITZ, HR (corresponding author), MIT,HOWARD HUGHES MED INST,DEPT BIOL,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA.
NR 60
TC 233
Z9 257
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 535
EP 541
DI 10.1038/351535a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400048
PM 1646401
DA 2026-03-10
ER

PT J
AU INGLES, CJ
   SHALES, M
   CRESS, WD
   TRIEZENBERG, SJ
   GREENBLATT, J
AF INGLES, CJ
   SHALES, M
   CRESS, WD
   TRIEZENBERG, SJ
   GREENBLATT, J
TI REDUCED BINDING OF TFIID TO TRANSCRIPTIONALLY COMPROMISED MUTANTS OF VP16
SO NATURE
LA English
DT Article
ID functional dissection; activation domain; mammalian-cells; rna-polymerase; proteins; expression; yeast; gene
AB ACTIVATOR proteins that control transcription initiation by RNA polymerase II 1,2 usually have two domains:  one binds to DNA, and the other activates transcription 3,4.  A particularly potent acidic 5,6 activation domain at the C terminus of the herpes simplex virus protein VP16 7-9 binds directly and selectively to the human and yeast TATA box-binding factor TFIID 10.  We have now investigated the biological significance of this in vitro interaction by using mutant forms of VP16 11.  For changes at the critical phenylalanine residue at position 442 of VP16 there was a good correlation between transactivation activity in vivo and the binding of VP16 to TFIID in vitro.  In contrast, mutants with reduced negative charge were more defective for binding than for activation.
C1 MICHIGAN STATE UNIV,DEPT BIOCHEM,E LANSING,MI 48824.
C3 Michigan State University
RP INGLES, CJ (corresponding author), UNIV TORONTO,BANTING & BEST DEPT MED RES,TORONTO M5G 1L6,ONTARIO,CANADA.
NR 17
TC 295
Z9 313
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 588
EP 590
DI 10.1038/351588a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400066
PM 1646402
DA 2026-03-10
ER

PT J
AU DESHAIES, RJ
   SANDERS, SL
   FELDHEIM, DA
   SCHEKMAN, R
AF DESHAIES, RJ
   SANDERS, SL
   FELDHEIM, DA
   SCHEKMAN, R
TI ASSEMBLY OF YEAST SEC PROTEINS INVOLVED IN TRANSLOCATION INTO THE ENDOPLASMIC-RETICULUM INTO A MEMBRANE-BOUND MULTISUBUNIT COMPLEX
SO NATURE
LA English
DT Article
ID lambda-dna-replication; heat-shock protein; nucleoprotein structures; bacteriophage-lambda; initiation; gene; sequence; encodes; mutant; origin
AB SECRETORY-protein translocation into the endoplasmic reticulum (ER) is thought to be catalysed by integral membrane proteins. Genetic selections uncovered three Saccharomyces cerevisiae genes (SEC61, SEC62 and SEC63), mutations in which block import of precursor proteins into the ER lumen in vivo 1-3 and in vitro 2-4. The DNA sequences of SEC62 (ref. 4) and SEC63 (ref. 5) predict multispanning membrane proteins, and biochemical characterization of the SEC62 protein (Sec62) confirms that it is an integral ER membrane protein6. Here we show that Sec61, Sec62 and Sec63 are assembled with two additional proteins into a multisubunit membrane-associated complex. These results confirm previous predictions, based upon genetic interactions between the SEC genes, that Sec61, Sec62 and Sec63 act together to facilitate protein translocation into the ER.
C1 UNIV CALIF BERKELEY, DIV BIOCHEM & MOLEC BIOL, BERKELEY, CA 94720 USA.
C3 University of California System; University of California Berkeley
NR 22
TC 294
Z9 344
U1 1
U2 16
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 806
EP 808
DI 10.1038/349806a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600061
PM 2000150
DA 2026-03-10
ER

PT J
AU VANLOHUIZEN, M
   FRASCH, M
   WIENTJENS, E
   BERNS, A
AF VANLOHUIZEN, M
   FRASCH, M
   WIENTJENS, E
   BERNS, A
TI SEQUENCE SIMILARITY BETWEEN THE MAMMALIAN BMI-1 PROTOONCOGENE AND THE DROSOPHILA REGULATORY GENES PSC AND SU(Z)2
SO NATURE
LA English
DT Article
ID zeste; expression; melanogaster; transvection; complex
AB THE bmi-1 proto-oncogene can be activated by Moloney murine leukaemia proviral insertions in E-mu-myc transgenic mice 1,2.  It encodes a highly conserved nuclear protein of 324 amino acids which belongs to a family of proteins containing a putative new zinc-finger.  Another closely related member of this family is the mouse protein Mel-18 (ref. 3).  Here we report on the cloning and characterization of a homologous gene (D-bmi) from Drosophila melanogaster.  Our analysis indicates that distinct domains of the mouse Bmi-1 protein, including the putative zinc-finger motif, are highly conserved within the much larger D-Bmi protein.  Chromosomal localization and sequence comparison reveal that D-bmi is identical to Posterior Sex Combs (Psc) 4-6 and indicate that the conserved domains between mouse bmi and Psc are also conserved within Suppressor-2 of Zeste (Su(z)2) 6-8.
C1 UNIV AMSTERDAM,DEPT BIOCHEM,AMSTERDAM,NETHERLANDS.
   MAX PLANCK INST ENTWICKLUNGSBIOL,GENET ABT,W-7400 TUBINGEN,GERMANY.
C3 University of Amsterdam; Max Planck Society
RP VANLOHUIZEN, M (corresponding author), NETHERLANDS CANC INST,DIV MOLEC GENET,PLESMANLAAN 121,1066 CX AMSTERDAM,NETHERLANDS.
NR 22
TC 204
Z9 239
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 353
EP 355
DI 10.1038/353353a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400061
PM 1922340
DA 2026-03-10
ER

PT J
AU LAWSON, DM
   ARTYMIUK, PJ
   YEWDALL, SJ
   SMITH, JMA
   LIVINGSTONE, JC
   TREFFRY, A
   LUZZAGO, A
   LEVI, S
   AROSIO, P
   CESARENI, G
   THOMAS, CD
   SHAW, WV
   HARRISON, PM
AF LAWSON, DM
   ARTYMIUK, PJ
   YEWDALL, SJ
   SMITH, JMA
   LIVINGSTONE, JC
   TREFFRY, A
   LUZZAGO, A
   LEVI, S
   AROSIO, P
   CESARENI, G
   THOMAS, CD
   SHAW, WV
   HARRISON, PM
TI SOLVING THE STRUCTURE OF HUMAN H-FERRITIN BY GENETICALLY ENGINEERING INTERMOLECULAR CRYSTAL CONTACTS
SO NATURE
LA English
DT Article
ID horse spleen apoferritin; subunit gene; escherichia-coli; chain ferritins; iron; expression; resolution; identification; conservation; pseudogene
AB FERRITIN is important in iron homeostasis.  Its twenty-four chains of two types, H and L, assemble as a hollow shell providing an iron-storage cavity 1-3.  Ferritin molecules in cells containing high levels of iron tend to be rich in L chains, and may have a long-term storage function, whereas H-rich ferritins are more active in iron metabolism 3-7.  The molecular basis for the greater activity of H-rich ferritins has until now been obscure, largely because the structure of H-chain ferritin has remained unknown owing to the difficulties in obtaining crystals ordered enough for X-ray crystallographic analysis.  Here we report the three-dimensional structure of a human ferritin H-chain homopolymer.  By genetically engineering a change in the sequence of the intermolecular contact region, we obtained crystals isomorphous with the homologous rat L ferritin 8,9 and of high enough quality for X-ray diffraction analysis. The X-ray structure of human H ferritin shows a novel metal site embedded within each of its four-helix bundles and we suggest that ferroxidase activity associated with this site accounts for its rapid uptake of iron 10.
C1 UNIV SHEFFIELD,KREBS INST BIOMOLEC RES,DEPT MOLEC BIOL & BIOTECHNOL,SHEFFIELD S10 2TN,S YORKSHIRE,ENGLAND.
   EUROPEAN MOLEC BIOL LAB,W-6900 HEIDELBERG,GERMANY.
   UNIV MILANO,OSPED SAN RAFFAELE,DIPARTIMENTO SCI & TECNOL BIOMED,I-20132 MILAN,ITALY.
   UNIV ROMA TOR VERGATA,DIPARTIMENTO BIOL,I-00173 ROME,ITALY.
   UNIV LEICESTER,DEPT BIOCHEM,LEICESTER LE1 7HR,ENGLAND.
C3 University of Sheffield; European Molecular Biology Laboratory (EMBL); Consiglio Nazionale delle Ricerche (CNR); Istituto di Tecnologie Biomediche (ITB-CNR); University of Milan; Vita-Salute San Raffaele University; IRCCS Ospedale San Raffaele; University of Rome Tor Vergata; University of Leicester
FU Wellcome Trust Funding Source: Medline
NR 30
TC 731
Z9 836
U1 2
U2 111
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 541
EP 544
DI 10.1038/349541a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100073
PM 1992356
DA 2026-03-10
ER

PT J
AU HERNQUIST, L
   HUT, P
   KORMENDY, J
AF HERNQUIST, L
   HUT, P
   KORMENDY, J
TI A POST-CORE-COLLAPSE MODEL FOR THE NUCLEUS OF M33
SO NATURE
LA English
DT Article
AB RECENT high-resolution optical observations 1,2 show that the nucleus of the nearby spiral galaxy M33 has a small core radius and an unusually low velocity dispersion. These parameters yield a central dynamical timescale of only a few tens of millions of years, suggesting that the nucleus of M33 has undergone core collapse, as is believed to occur in globular clusters. Here we propose a model for the post-collapse core of M33. By analogy with globular clusters, the formation of tight binary systems powers the re-expansion of the core, and we expect in particular that low-mass X-ray binaries form with a rate about equal to that of all galactic globular clusters combined. About a dozen such binaries should be present, and their combined emission may explain the large (10(39) erg s-1) and enigmatic unresolved X-ray emission from the nucleus of M33. In addition, tidal formation of cataclysmic binaries may lead to a nova rate of greater-than-or-similar-to 1 per century. Numerous blue stragglers have probably formed through mergers caused by stellar collisions, but their density is probably too low to explain the blue colour of the nucleus. Young stars are the likely cause for the colour, and their presence may complicate the simple dynamical picture presented here.
C1 INST ADV STUDY, PRINCETON, NJ 08540 USA.
   UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA.
C3 Institute for Advanced Study - USA; University of Hawaii System
RP HERNQUIST, L (corresponding author), LICK OBSERV, SANTA CRUZ, CA 95064 USA.
NR 34
TC 16
Z9 16
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 376
EP 377
DI 10.1038/354376a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100044
DA 2026-03-10
ER

PT J
AU COALE, KH
   CHIN, CS
   MASSOTH, GJ
   JOHNSON, KS
   BAKER, ET
AF COALE, KH
   CHIN, CS
   MASSOTH, GJ
   JOHNSON, KS
   BAKER, ET
TI INSITU CHEMICAL MAPPING OF DISSOLVED IRON AND MANGANESE IN HYDROTHERMAL PLUMES
SO NATURE
LA English
DT Article
ID east pacific rise; de-fuca ridge; northeast pacific; vent field; distributions; 21-degrees-n; chemistry; seawater; fluids; ocean
AB HYDROTHERMAL vents along mid-ocean ridges are an important source of elements such as lithium, silicon, manganese and iron to the world's oceans 1.  The venting produces both episodic and steady-state hydrothermal plumes with unique thermochemical signatures in the mid-water column. The particulate phases in these plumes (predominantly iron oxides and hydroxides) also scavenge phosphorus, vanadium, arsenic, lead, polonium and several rare-earth elements from sea water 2-5.  Thus, on a global scale, hydrothermal plumes are both a source for some elements and a sink for others. Ultimately, the particulate metals precipitated from plumes form extensive regions of metalliferous sediments over the crests and flanks of mid-ocean ridges 6,7.  Although the metalliferous sediment coverage is vast and well documented, only a tiny fraction of the vents responsible for these sediments have been located (Fig. 1a). To date, both the number and location of hydrothermal vents and the detailed distribution of chemical constituents within the resultant plumes are poorly understood because of under-sampling of the mid-ocean ridges and the overlying waters. Here we present the results of high-resolution mapping of the chemical and thermal characteristics of hydrothermal plumes in near real time using a novel submersible chemical analyser (Scanner) 8,9 and a conductivity/temperature/depth/transmissometer instrument package (CTDT) 10.  We show that the kinetics of iron oxidation in the plume can be used to constrain estimates of the plume's age, and that variation in the ratio of manganese content to excess heat can be explained by the mixing of several different vent fluids.
C1 NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115.
   MONTEREY BAY AQUARIUM RES INST,PACIFIC GROVE,CA 93950.
C3 National Oceanic Atmospheric Admin (NOAA) - USA; Monterey Bay Aquarium Research Institute
RP COALE, KH (corresponding author), MOSS LANDING MARINE LABS,POB 450,MOSS LANDING,CA 95039, USA.
NR 28
TC 64
Z9 69
U1 0
U2 43
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 325
EP 328
DI 10.1038/352325a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900067
DA 2026-03-10
ER

PT J
AU PHINNEY, ES
   SIGURDSSON, S
AF PHINNEY, ES
   SIGURDSSON, S
TI EJECTION OF PULSARS AND BINARIES TO THE OUTSKIRTS OF GLOBULAR-CLUSTERS
SO NATURE
LA English
DT Article
ID psr 1913+16
AB THREE-BODY interactions can eject stars, singly or in binaries, from the core of a globular cluster to its outskirts, whither dynamical friction may take more than 10(8) yr to return them.  We show here that such a process can explain why the binary pulsar 2127+ 11C in the cluster M15 (and perhaps 1744-24A in Terzan 5) is now far from the cluster core.  A suitable encounter could have given the pulsar enough velocity to eject it to its present position, and also replaced its original stellar companion with a neutron star.  For ejection of PSR2127+11C to be likely, the core of M15 must be composed of heavy degenerate stars at a density greater than 10(7) pc-3, maintained for greater-than-or-equal-to 10(8) yr; this is consistent with previous dynamical estimates.  A natural combination of factors enables us to see 2127+11C: a binary of longer period could not have received a large enough impulse to escape the core, whereas one of shorter period would have been ejected from the cluster or would have collapsed because of orbital decay by gravitational radiation.  Pulsars and pulsar binaries ejected from clusters will contribute to the birth rate of recycled pulsars in the inner Galazy.
RP PHINNEY, ES (corresponding author), CALTECH,PASADENA,CA 91125, USA.
NR 18
TC 95
Z9 96
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 220
EP 223
DI 10.1038/349220a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900047
DA 2026-03-10
ER

PT J
AU SCHIERING, N
   KABSCH, W
   MOORE, MJ
   DISTEFANO, MD
   WALSH, CT
   PAI, EF
AF SCHIERING, N
   KABSCH, W
   MOORE, MJ
   DISTEFANO, MD
   WALSH, CT
   PAI, EF
TI STRUCTURE OF THE DETOXIFICATION CATALYST MERCURIC ION REDUCTASE FROM BACILLUS SP STRAIN-RC607
SO NATURE
LA English
DT Article
ID x-ray-diffraction; glutathione-reductase; active-site; organomercurial lyase; nucleotide-sequence; binding; enzyme; mutant; nadph; purification
AB SEVERAL hundred million tons of toxic mercurials are dispersed in the biosphere 1.  Microbes can detoxify organo-mercurials and mercury salts through sequential action of two enzymes, organomercury lyase 2 and mercuric ion reductase (MerA) 3-5.  The latter, a homodimer with homology to the FAD-dependent disulphide oxidoreductases 6, catalyses the reaction NADPH + Hg(II) --> NADP+ + H+ + Hg(0), one of the very rare enzymic reactions with metal substrates.  Human glutathione reductase 7,8 serves as a reference molecule for FAD-dependent disulphide reductases and between its primary structure 9 and that of MerA from Tn501 (Pseudomonas), Tn21 (Shigella), pI258 (Staphylococcus) and Bacillus, 25-30% of the residues have been conserved 10,11.  All MerAs have a C-terminal extension about 15 residues long but have very varied N termini.  Although the enzyme from Streptomyces lividans has no addition, from Pseudomonas aeruginosa Tn501 and Bacillus sp. strain RC607 it has one and two copies respectively of a domain of 80-85 residues, highly homologous to MerP, the periplasmic component of proteins encoded by the mer operon 11.  These domains can be proteolytically cleaved off without changing the catalytic efficiency 3.  We report here the crystal structure of MerA from the Gram-positive bacterium Bacillus sp. strain RC607.   Analysis of its complexes with nicotinamide dinucleotide substrates and the inhibitor Cd(II) reveals how limited structural changes enable an enzyme to accept as substrate what used to be a dangerous inhibitor.  Knowledge of the mode of mercury ligation is a prerequisite for understanding this unique detoxification mechanism.
C1 HARVARD UNIV,SCH MED,DEPT BIOL CHEM & MOLEC PHARMACOL,240 LONGWOOD AVE,BOSTON,MA 02115.
   MAX PLANCK INST MED RES,BIOPHYS ABT,W-6900 HEIDELBERG 1,GERMANY.
C3 Harvard University; Harvard Medical School; Max Planck Society
NR 35
TC 182
Z9 201
U1 0
U2 39
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 168
EP 172
DI 10.1038/352168a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700061
PM 2067577
DA 2026-03-10
ER

PT J
AU MURPHY, AP
AF MURPHY, AP
TI CHEMICAL REMOVAL OF NITRATE FROM WATER
SO NATURE
LA English
DT Article
AB High levels of nitrate in ground water can pose a serious health risk.  Reduction of nitrate to nitrite in the gut may cause methemoglobinaemia 1 both in newborn infants and in adults deficient in glucose-phosphate dehydrogenase 2.  Under abnormal circumstances, reduction to nitrite can also occur in the stomach to form N-nitrosamines, a postulated cause of stomach cancer 3.  Nitrate outflow onto shallow continental shelves can promote nearshore algal blooms.  Both natural and anthropogenic sources contribute to nitrate pollution.  In the United States 4 and Europe 5, legislation now specifies a maximum permissible nitrate level in drinking water.  Techniques such as selective ion exchange 6, reverse osmosis, electrodialysis and distillation exist to transfer nitrate between two bodies of water, but only biological processes are presently available for nitrate destruction.  Here I describe a chemical process in which aluminium powder reduces nitrate to ammonia, nitrogen and nitrite.  In a pH range of 9 to 10.5, selective reduction of nitrate relative to sulphate is possible, and between pH 9.1 and 9.3, loss of the reductant through decomposition of water can be minimized to less than 2%.  Subsequent control of pH and concentrations of dissolved aluminium, nitrite and ammonia should be possible at a realistic cost, making this process potentially useful for combating nitrate pollution.
RP MURPHY, AP (corresponding author), US BUR RECLAMAT,DENVER FED CTR,POB 25007,DENVER,CO 80225, USA.
NR 11
TC 187
Z9 212
U1 3
U2 116
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 223
EP 225
DI 10.1038/350223a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900054
DA 2026-03-10
ER

PT J
AU WAGNER, JA
   COZENS, AL
   SCHULMAN, H
   GRUENERT, DC
   STRYER, L
   GARDNER, P
AF WAGNER, JA
   COZENS, AL
   SCHULMAN, H
   GRUENERT, DC
   STRYER, L
   GARDNER, P
TI ACTIVATION OF CHLORIDE CHANNELS IN NORMAL AND CYSTIC-FIBROSIS AIRWAY EPITHELIAL-CELLS BY MULTIFUNCTIONAL CALCIUM CALMODULIN-DEPENDENT PROTEIN-KINASE
SO NATURE
LA English
DT Article
ID phosphorylation; identification; conductance; gene
AB CYSTIC fibrosis is associated with defective regulation of apical membrane chloride channels in airway epithelial cells.  These channels in normal cells are activated by cyclic AMP-dependent protein kinase 1,2 and protein kinase C 3,4.  In cystic fibrosis these kinases fail to activate otherwise normal Cl- channels 1-4.  But Cl- flux in cystic fibrosis cells, as in normal cells, can be activated by raising intracellular Ca2+ (refs 5-10).  We report here whole-cell patch clamp studies of normal and cystic fibrosis-derived airway epithelial cells showing that Cl- channel activation by Ca2+ is mediated by multifunctional Ca2+/calmodulin-dependent protein kinase.  We find that intracellular application of activated kinase and ATP activates a Cl- current similar to that activated by a Ca2+ ionophore, that peptide inhibitors of either the kinase or calmodulin block Ca2+-dependent activation of Cl- channels, and that a peptide inhibitor of protein kinase C does not block Ca2+-dependent activation.  Ca2+/calmodulin activation of Cl- channels presents a pathway with therapeutic potential for circumventing defective regulation of Cl- channels in cystic fibrosis.
C1 STANFORD UNIV,MED CTR,SCH MED,DEPT MED,FALK CVRC,STANFORD,CA 94305.
   STANFORD UNIV,MED CTR,SCH MED,DEPT CELL BIOL,STANFORD,CA 94305.
   UNIV CALIF SAN FRANCISCO,CARDIOVASC RES INST,SAN FRANCISCO,CA 94143.
   STANFORD UNIV,MED CTR,SCH MED,DEPT PHARMACOL,STANFORD,CA 94305.
C3 Stanford University; Stanford University; University of California System; University of California San Francisco; Stanford University
NR 24
TC 195
Z9 205
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 793
EP 796
DI 10.1038/349793a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600057
PM 1705665
DA 2026-03-10
ER

PT J
AU PICKER, LJ
   KISHIMOTO, TK
   SMITH, CW
   WARNOCK, RA
   BUTCHER, EC
AF PICKER, LJ
   KISHIMOTO, TK
   SMITH, CW
   WARNOCK, RA
   BUTCHER, EC
TI ELAM-1 IS AN ADHESION MOLECULE FOR SKIN-HOMING T-CELLS
SO NATURE
LA English
DT Article
ID leukocyte adhesion; endothelial activation; lymph-nodes; lymphocytes; receptor; proteins; antigen; cd2
AB ENDOTHELIAL cell leukocyte adhesion molecule-1 (ELAM-1) has been described as an inducible endothelial cell-adhesion molecule for neutrophils, and is believed to have a key role in the extravasation of these cells at sites of acute inflammation 1-3.  Here we report that ELAM-1-transfected COS cells also bind a unique skin-associated subset of circulating memory T cells defined by the expression of the cutaneous lymphocyte-associated antigen 4,5.  T cells expressing this antigen bind at least as well as neutrophils to expressed ELAM-1, whereas other lymphocytes in the peripheral blood bind poorly, or not at all. Immunohistological survey of chronically inflamed tissue specimens revealed that vascular expression of ELAM-1 occurs at cutaneous sites in preference to noncutaneous sites.  We conclude that at sites of chronic inflammation, ELAM-1 may function as a skin vascular addressin, a tissue-selective endothelial cell-adhesion molecule for skin-homing memory T lymphocytes.
C1 VET ADM MED CTR,CTR MOLEC MED,PALO ALTO,CA 94304.
   STANFORD UNIV,MED CTR,SCH MED,CTR DIGEST DIS,STANFORD,CA 94305.
   BAYLOR UNIV,DEPT PEDIAT,LEUKOCYTE BIOL SECT,HOUSTON,TX 77030.
C3 US Department of Veterans Affairs; Veterans Health Administration (VHA); Stanford University; Baylor University
RP PICKER, LJ (corresponding author), STANFORD UNIV,MED CTR,SCH MED,DEPT PATHOL,IMMUNOL & VASC BIOL LAB,STANFORD,CA 94305, USA.
NR 23
TC 822
Z9 868
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 796
EP 799
DI 10.1038/349796a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600058
PM 1705666
DA 2026-03-10
ER

PT J
AU OHMOTO, H
   HAYASHI, K
   ONUMA, K
   TSUKAMOTO, K
   KITAKAZE, A
   NAKANO, Y
   YAMAMOTO, Y
AF OHMOTO, H
   HAYASHI, K
   ONUMA, K
   TSUKAMOTO, K
   KITAKAZE, A
   NAKANO, Y
   YAMAMOTO, Y
TI SOLUBILITY AND REACTION-KINETICS OF SOLUTION SOLID REACTIONS DETERMINED BY INSITU OBSERVATIONS
SO NATURE
LA English
DT Article
ID molecular growth steps; aqueous-solution
AB THE solubilities of solid compounds in solution, and the kinetics of the reactions that take place between solid and liquid phases, have usually been studied by indirect methods, which are often time-consuming and can be inaccurate.  Here we present a new experimental method, using the titration principle and in situ observation of solution-solid reactions on a solid surface, which allows the rapid acquisition of accurate data on the dissolution and growth rates and the solubilities (both stoichiometric and nonstoichiometric) of solids in a variety of aqueous and organic solutions at temperatures up to 350-degrees-C and pressures up to 200 bar.  This technique should provide new opportunities for determining the phase diagrams of complex systems and for studying crystal growth.
C1 PENN STATE UNIV,DEPT GEOSCI,UNIVERSITY PK,PA 16802.
C3 Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park
RP OHMOTO, H (corresponding author), TOHOKU UNIV,FAC SCI,INST MINERAL PETROL & ECON GEOL,SENDAI,MIYAGI 980,JAPAN.
NR 7
TC 17
Z9 18
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 634
EP 636
DI 10.1038/351634a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200058
DA 2026-03-10
ER

PT J
AU STIAVELLI, M
   MOLLER, P
   ZEILINGER, WW
AF STIAVELLI, M
   MOLLER, P
   ZEILINGER, WW
TI HIGH-RESOLUTION OPTICAL OBSERVATIONS COMPARED TO RADIO STRUCTURE OF THE JET IN M87
SO NATURE
LA English
DT Article
AB THE jet in the nearby elliptical galaxy NGC4486 (M87) is a prototype of this kind of nuclear activity 1. High-resolution observations over a wide wavelength range have been used to investigate the propagation of energy along the jet and the radiation mechanism, but these studies have been hampered by the much lower resolution available at optical compared with radio wavelengths. Here we present high-resolution multi-colour images of the jet, obtained using image reconstruction techniques. Morphological features in the jet known from radio observations are seen in our optical images. In particular, we find that the radio-bright 'knots' are spatially extended, and that there is significant emission in the regions between the knots. There is also evidence for limb-brightening at a number of positions along the jet. Taken together, our observations suggest that the jet propagates essentially free of losses, generating radio and optical emission at its edges, where interstellar material may be encountered.
RP STIAVELLI, M (corresponding author), EUROPEAN SO OBSERV,W-8046 GARCHING,GERMANY.
NR 10
TC 10
Z9 10
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 132
EP 134
DI 10.1038/354132a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000053
DA 2026-03-10
ER

PT J
AU FINKELSTEIN, AV
   REVA, BA
AF FINKELSTEIN, AV
   REVA, BA
TI A SEARCH FOR THE MOST STABLE FOLDS OF PROTEIN CHAINS
SO NATURE
LA English
DT Article
ID secondary structure; globular-proteins; spin-glasses; patterns
AB IT is generally believed that it is not sensible to search for a thermodynamically stable structure of a protein 1,2 because neither a molecule nor a computer can look through all the 3 100 possible (for 100 residues) chain conformations. Here we show that the use of a molecular field theory for the long-range interactions, the use of one-dimensional statistical mechanics for the short-range ones and the discovery that there are 3,4 and there must be 5,6 only a small discrete set of folding patterns, make it possible to examine all the variety of 'potentially stable' structures. The general approach and its application is demonstrated here by calculation of stable folds for some beta-domains. The most stable of these folds correspond to the observed structures.
C1 ACAD SCI USSR, RES COMP CTR, PUSHCHINO 142292, USSR.
C3 Russian Academy of Sciences
RP FINKELSTEIN, AV (corresponding author), ACAD SCI USSR, INST PROT RES, PUSHCHINO 142292, USSR.
NR 29
TC 125
Z9 135
U1 0
U2 10
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 497
EP 499
DI 10.1038/351497a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800061
PM 2046752
DA 2026-03-10
ER

PT J
AU WEAVER, AJ
   SARACHIK, ES
   MAROTZE, J
AF WEAVER, AJ
   SARACHIK, ES
   MAROTZE, J
TI FRESH-WATER FLUX FORCING OF DECADAL AND INTERDECADAL OCEANIC VARIABILITY
SO NATURE
LA English
DT Article
ID north-atlantic; salinity
AB THE ocean's thermohaline circulation, driven by fluxes of freshwater and heat through the ocean's surface, is important in the transport of heat from low to high latitudes. Changes in the intensity of this circulation, and hence the poleward heat transport, would have a significant effect on global climate. Numerous observations of the air-sea-ice climate system in and around the North Atlantic show significant variability on decadal and interdecadal timescales 1-11; these timescales suggest that the source of the variability lies in the ocean itself. Here we present the results of three numerical experiments which show the importance of freshwater flux forcing (the difference between precipitation and evaporation, or 'P - E') in exciting decadal and interdecadal oceanic variability. If a sufficiently strong local minimum exists in this P - E forcing field (as is observed over the Greenland Sea), self-sustained oscillations of the ocean circulation may be excited. We propose that such variability may be important in interpreting observations of decadal/interdecadal variability in the air-sea-ice climate system.
C1 MCGILL UNIV,CTR CLIMATE & GLOBAL CHANGE RES,MONTREAL H3A 2K6,QUEBEC,CANADA.
   UNIV WASHINGTON,JOINT INST STUDY ATMOSPHERE & OCEAN,SEATTLE,WA 98195.
   MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139.
C3 McGill University; University of Washington; University of Washington Seattle; Massachusetts Institute of Technology (MIT)
RP WEAVER, AJ (corresponding author), MCGILL UNIV,DEPT METEOROL,805 SHERBROOKE ST W,MONTREAL H3A 2K6,QUEBEC,CANADA.
NR 23
TC 139
Z9 145
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 836
EP 838
DI 10.1038/353836a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200056
DA 2026-03-10
ER

PT J
AU GRANT, ER
   WHITE, MG
AF GRANT, ER
   WHITE, MG
TI ZEKE THRESHOLD PHOTOELECTRON-SPECTROSCOPY
SO NATURE
LA English
DT Article
ID photoionization
C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973.
C3 United States Department of Energy (DOE); Brookhaven National Laboratory
RP GRANT, ER (corresponding author), PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907, USA.
NR 11
TC 44
Z9 46
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 249
EP 250
DI 10.1038/354249a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800055
DA 2026-03-10
ER

PT J
AU WIGLEY, TML
AF WIGLEY, TML
TI COULD REDUCING FOSSIL-FUEL EMISSIONS CAUSE GLOBAL WARMING
SO NATURE
LA English
DT Article
ID cloud albedo; climate; aerosols
AB WHEN fossil fuel is burned, both carbon dioxide and sulphur dioxide are added to the atmosphere.  The former should cause warming of the lower atmosphere by enhancing the greenhouse effect, whereas the latter, by producing sulphate aerosols, may cause a cooling effect.  The possibility that these two processes could offset each other was suggested many years ago (see, for example, ref. 1), but during most of the intervening period, attention has focused on the greenhouse effect. Interest in tropospheric aerosols has, however, recently been rekindled by the realization that they may influence climate, not only through clear-sky radiative effects 2-5, but also by modifying cloud albedo 6-8. Here I examine the sensitivity of the climate system to simultaneous changes in SO2 and CO2 emissions, as might occur if controls were imposed on fossil-fuel use.  Over the next 10-30 years, it is conceivable that the increased radiative forcing due to SO2 concentration changes could more than offset reductions in radiative forcing due to reduced CO2 emissions.
RP WIGLEY, TML (corresponding author), UNIV E ANGLIA,CLIMAT RES UNIT,NORWICH NR4 7TJ,NORFOLK,ENGLAND.
NR 16
TC 124
Z9 132
U1 0
U2 41
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 503
EP 506
DI 10.1038/349503a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100058
DA 2026-03-10
ER

PT J
AU LIVINGSTON, W
AF LIVINGSTON, W
TI RADIAL FILAMENTARY STRUCTURE IN A SUNSPOT UMBRA
SO NATURE
LA English
DT Article
ID light-bridges; dots
AB THAT the dark umbrae of sunspots are not uniformly dark has long been recognized 1, but our knowledge of umbral structure is still limited.  Here I present two white-light photographs of the solar disk, of different exposure, recently obtained during exceptional seeing conditions with the McMath Telescope on Kitt Peak (Fig. 1).  The shorter exposure reveals the solar granulation, and the longer brings out details in the darker umbrae.  When these two images are suitably combined, the umbra of one small sunspot is resolved into an approximately filamentary structure, connecting to the penumbra, along with featureless voids.  A 'light bridge' partially spanning the spot is found to have a broader underlying filamentary foundation that completes the crossing.  These photographs suggest that the contemporary view of umbral structure as consisting primarily of granulation or 'umbral dots' is questionable.  Given that a sunspot is a place where kilogauss magnetic fields concentrate and diverge outwards, filamentary brightness modulation can perhaps be attributed to partly inclined field lines, and the voids may be places where the field becomes perpendicular to the surface.
RP LIVINGSTON, W (corresponding author), NATL ASTRON OPT OBSERV,NATL SOLAR OBSERV,POB 26732,TUCSON,AZ 85726, USA.
NR 15
TC 32
Z9 32
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 45
EP 46
DI 10.1038/350045a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300057
DA 2026-03-10
ER

PT J
AU DERANGO, P
   LEES, M
   LEJAY, P
   SULPICE, A
   TOURNIER, R
   INGOLD, M
   GERMI, P
   PERNET, M
AF DERANGO, P
   LEES, M
   LEJAY, P
   SULPICE, A
   TOURNIER, R
   INGOLD, M
   GERMI, P
   PERNET, M
TI TEXTURING OF MAGNETIC-MATERIALS AT HIGH-TEMPERATURE BY SOLIDIFICATION IN A MAGNETIC-FIELD
SO NATURE
LA English
DT Article
ID superconducting property
AB THE ability to impose a preferred orientation, or 'texture', on a crystalline material is important in many fields of materials science.  In general, crystalline materials are more or less anisotropic in their properties, depending on their lattice structure, and texturing allows the most favourable direction (for example, for current flow or magnetic susceptibility) to be used in applications.  Ferromagnetic materials can be textured by 'magnetic annealing'-the orientation of powdered material in a magnetic field, usually followed by a sintering step-but this must be done at temperatures below the material's Curie temperature.  Here we present a new method of texturing materials that have a residual anisotropy in their magnetic susceptibility at high temperature, by solidification in a magnetic field.  This one-step process, which may be called 'paramagnetic annealing', is demonstrated by application to the high-temperature superconductor YBa2Cu3O7.
C1 CNRS,CRISTALLOG LAB,F-38042 GRENOBLE,FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS)
RP DERANGO, P (corresponding author), UNIV JOSEPH FOURIER,CTR RECH TRES BASSES TEMP,CNRS,BP 166X,F-38042 GRENOBLE,FRANCE.
NR 10
TC 322
Z9 327
U1 0
U2 94
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 770
EP 772
DI 10.1038/349770a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600048
DA 2026-03-10
ER

PT J
AU RICHARDS, KJ
   POLLARD, RT
AF RICHARDS, KJ
   POLLARD, RT
TI STRUCTURE OF THE UPPER OCEAN IN THE WESTERN EQUATORIAL PACIFIC
SO NATURE
LA English
DT Article
AB THE western equatorial Pacific has an important role in the El Nino/Southern Oscillation climate cycle 1,2, and sea-surface temperature anomalies in this area are known to affect the global atmospheric circulation 3.  Little is known, however, about the factors that control the response of the upper ocean, and hence sea surface temperature, to changes in atmospheric conditions.  Here we present observations of the density and current structure of the upper layers of the western equatorial Pacific Ocean.  We observed frontal features with temperature differences of 1-degrees-C extending from the surface down to a depth of 150 m, a strong salinity front associated with a surface convergence, and interleaving of high- and low-salinity waters in 10-m-thick layers that extended for several hundred kilometres in the north-south direction.  The large spatial and temporal variability in temperature and salinity observed must influence heat transport, and hence the ocean response to atmospheric forcing (in particular the response to westerly wind bursts, which are thought to be precursors to an El Nino).  We estimate the horizontal diffusion coefficient of the interleaving, which indicates that the observed layering may contribute to horizontal mixing within the thermocline.
C1 INST OCEANOG SCI,RENNELL CTR,CHILWORTH RES CTR,SOUTHAMPTON SO1 7NS,ENGLAND.
C3 University of Southampton; NERC National Oceanography Centre
RP RICHARDS, KJ (corresponding author), UNIV SOUTHAMPTON,DEPT OCEANOG,SOUTHAMPTON SO9 5NH,HANTS,ENGLAND.
NR 14
TC 28
Z9 28
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 48
EP 50
DI 10.1038/350048a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300059
DA 2026-03-10
ER

PT J
AU WONG, YH
   FEDERMAN, A
   PACE, AM
   ZACHARY, I
   EVANS, T
   POUYSSEGUR, J
   BOURNE, HR
AF WONG, YH
   FEDERMAN, A
   PACE, AM
   ZACHARY, I
   EVANS, T
   POUYSSEGUR, J
   BOURNE, HR
TI MUTANT ALPHA-SUBUNITS OF GI2 INHIBIT CYCLIC-AMP ACCUMULATION
SO NATURE
LA English
DT Article
ID binding regulatory component; adenylate-cyclase; g-proteins; mutations; membranes; receptor; site; identification; dissociation; stimulation
AB ONE or more of three G(i) proteins, G(i1-3), mediates hormonal inhibition of adenylyl cyclase 1-3. Whether this inhibition is mediated by the alpha or by the beta-gamma-subunits of G(i) proteins is unclear 1,2. Mutations inhibiting the intrinsic GTPase activity of another G protein, the stimulatory regulator of adenylyl cyclase (G(s)), constitutively activate it by replacing either of two conserved amino acids in its alpha-subunit (alpha-s) 4-7. These mutations create the gsp oncogene which is found in human pituitary and thyroid tumours 5,8. In a second group of human endocrine tumours, somatic mutations in the alpha-subunit of G(i2) replace a residue cognate to one of those affected by gsp mutations 8. This implies that the mutations convert the alpha-i2 gene into a dominantly acting oncogene, called gip2 (ref. 8), and that the mutant alpha-i2 subunits are constitutively active. We have therefore assessed cyclic AMP accumulation in cultured cells which stably or transiently express exogenous wild-type alpha-i2 complementary DNA or either of two mutant alpha-i2 cDNAs. The results show that putatively oncogenic mutations in alpha-i2 constitutively activate the protein's ability to inhibit cAMP accumulation.
C1 UNIV CALIF SAN FRANCISCO, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA.
   GENENTECH INC, San Francisco, CA 94080 USA.
   UNIV CALIF SAN FRANCISCO, DEPT MED, SAN FRANCISCO, CA 94143 USA.
   UNIV CALIF SAN FRANCISCO, CARDIOVASC RES INST, SAN FRANCISCO, CA 94143 USA.
   UNIV NICE, FAC SCI, CNRS, CTR BIOCHIM, F-06034 NICE, FRANCE.
C3 University of California System; University of California San Francisco; Roche Holding; Roche Holding USA; Genentech; University of California System; University of California San Francisco; University of California System; University of California San Francisco; Centre National de la Recherche Scientifique (CNRS); Universite Cote d'Azur
NR 30
TC 256
Z9 272
U1 0
U2 4
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 63
EP 65
DI 10.1038/351063a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300060
PM 1851251
DA 2026-03-10
ER

PT J
AU ANIKSZTEJN, L
   BENARI, Y
AF ANIKSZTEJN, L
   BENARI, Y
TI NOVEL FORM OF LONG-TERM POTENTIATION PRODUCED BY A K+ CHANNEL BLOCKER IN THE HIPPOCAMPUS
SO NATURE
LA English
DT Article
ID synaptic transmission; pyramidal cells; nmda receptors; after-hyperpolarization; potassium conductances; lasting potentiation; neurons; calcium; antagonists; invitro
AB LONG-term potentiation (LTP) of synaptic transmission in the hippocampus is a widely studied model of memory processes1.  In the CA1 region, LTP is triggered by the entry of CA2+ through N-methyl-D-aspartate (NMDA) receptor channels and maintained by the activation of CA2+-sensitive intracellular messengers2,3.  We now report that in CA1, a transient block by tetraethylammonium of I(C), I(M) and the delayed rectifier (I(K)) produces a Ca2+-dependent NMDA-independent form of LTP.  Our results suggest that this new form of LTP (referred as to LTP(K)) is induced by a transient enhanced release of glutamate which generates a depolarization by way of the non-NMDA receptors and the consequent activation of voltage -dependent Ca2+ channels.
RP ANIKSZTEJN, L (corresponding author), HOP PORT ROYAL,INSERM,U29,123 BLVD PORT ROYAL,F-75014 PARIS,FRANCE.
NR 33
TC 257
Z9 278
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 67
EP 69
DI 10.1038/349067a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100052
PM 1845914
DA 2026-03-10
ER

PT J
AU NOJI, S
   NOHNO, T
   KOYAMA, E
   MUTO, K
   OHYAMA, K
   AOKI, Y
   TAMURA, K
   OHSUGI, K
   IDE, H
   TANIGUCHI, S
   SAITO, T
AF NOJI, S
   NOHNO, T
   KOYAMA, E
   MUTO, K
   OHYAMA, K
   AOKI, Y
   TAMURA, K
   OHSUGI, K
   IDE, H
   TANIGUCHI, S
   SAITO, T
TI RETINOIC ACID INDUCES POLARIZING ACTIVITY BUT IS UNLIKELY TO BE A MORPHOGEN IN THE CHICK LIMB BUD
SO NATURE
LA English
DT Article
ID receptor genes; differential expression; positional information; local application; homeobox gene; pattern; cells; identification; element; alpha
AB RETINOIC acid is a putative morphogen in limb formation in the chick and other vertebrates 1-5. In chick limb formation, it is thought that retinoic acid is released from the zone of polarizing activity (ZPA) and the concentration gradient of retinoic acid formed from the posterior to the anterior provides positional cues for digit formation 1-4,6. Implantation of a bead containing retinoic acid at the anterior margin of the limb bud induces a mirror-image symmetrical duplication of the digit pattern similar to that observed when the ZPA is grafted into the anterior margin of the host limb bud 7,8. Also, the level of endogenous retinoic acid (25 nM on average) is higher in the posterior one third of the limb bud 1,6. We found that when the bead containing either retinoic acid or an analogue but not the ZPA, was implanted in the anterior margin of the chick limb bud, expression of the retinoic acid receptor type-beta gene was induced around the bead within 4 h. These results indicate that exogenous retinoic acid is not identical with the ZPA morphogen. As the anterior tissue exposed to retinoic acid has polarizing activity 9, we conclude that the primary function of exogenous retinoic acid is to induce polarizing activity in the limb bud.
C1 OKAYAMA UNIV, SCH DENT,DEPT ORAL & MAXILLOFACIAL SURG 1, OKAYAMA 700, JAPAN.
   OKAYAMA UNIV, SCH DENT,DEPT ORAL & MAXILLOFACIAL SURG 2, OKAYAMA 700, JAPAN.
   KAWASAKI MED SCH, DEPT PHARMACOL, KURASHIKI, OKAYAMA 70101, JAPAN.
   TOHOKU UNIV, INST BIOL, SENDAI, MIYAGI 980, JAPAN.
C3 Okayama University; Okayama University; Kawasaki Medical School; Tohoku University
RP NOJI, S (corresponding author), OKAYAMA UNIV, SCH DENT, DEPT BIOCHEM, 2-5-1 SHIKATA CHO, OKAYAMA 700, JAPAN.
NR 29
TC 250
Z9 263
U1 0
U2 6
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 83
EP 86
DI 10.1038/350083a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300072
PM 1848357
DA 2026-03-10
ER

PT J
AU SHUSTER, SM
   WADE, MJ
AF SHUSTER, SM
   WADE, MJ
TI EQUAL MATING SUCCESS AMONG MALE REPRODUCTIVE STRATEGIES IN A MARINE ISOPOD
SO NATURE
LA English
DT Article
ID sexual selection; female choice; male morphs; behavior; dimorphism; tactics
AB THREE genetically discrete male morphs coexist in Paracerceis sculpta, a Gulf of California marine isopod 1-5.  The large alpha-males defend harems within intertidal sponges, the smaller beta-males mimic female behaviour and morphology, and the tiny gamma-males invade and sequester themselves within large harems.  If selection is responsible for maintaining this polymorphism, then the mean fitness of each male morph must be equal over time 6-9.  Here we report that average reproductive success is equivalent among the three male morphs in monthly population samples collected over two years.  We have investigated the total opportunity for sexual selection within and among morphs, and find that < 0.10% of the total opportunity for sexual selection occurs among morphs.  Furthermore, alleles responsible for the expression of this polymorphism conform to the Hardy-Weinberg equilibrium, indicating the absence of differential natural selection among morphs.  Conditions necessary for stable coexistence of three alternative male reproductive strategies seem to exist in nature.
C1 UNIV CHICAGO,DEPT ECOL & EVOLUT,CHICAGO,IL 60637.
C3 University of Chicago
NR 30
TC 237
Z9 263
U1 0
U2 90
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 608
EP 610
DI 10.1038/350608a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200059
DA 2026-03-10
ER

PT J
AU SHEN, SH
   BASTIEN, L
   POSNER, BI
   CHRETIEN, P
AF SHEN, SH
   BASTIEN, L
   POSNER, BI
   CHRETIEN, P
TI A PROTEIN-TYROSINE PHOSPHATASE WITH SEQUENCE SIMILARITY TO THE SH2 DOMAIN OF THE PROTEIN-TYROSINE KINASES
SO NATURE
LA English
DT Article
ID nucleotide-sequence; phospholipase-c; src gene; family; oncogene; member; transduction; expression; region
AB THE phosphorylation of proteins at tyrosine residues is critical in cellular signal transduction, neoplastic transformation and control of the mitotic cycle 1.  These mechanisms are regulated by the activities of both protein-tyrosine kinases (PTKs) and protein-tyrosine phosphatases (PTPases) 2.  As in the PTKs, there are two classes of PTPases:  membrane associated, receptor-like enzymes 3-5 and soluble proteins 3,6,7.  Here we report the isolation of a complementary DNA clone encoding a new form of soluble PTPase, PTPIC. The enzyme possesses a large noncatalytic region at the N terminus which unexpectedly contains two adjacent copies of the Src homology region 2 (the SH2 domain) found in various nonreceptor PTKs 8 and other cytoplasmic signalling proteins 9-11. As with other SH2 sequences, the SH2 domains of PTPIC formed high-affinity complexes with the activated epidermal growth factor receptor and other phosphotyrosine-containing proteins. These results suggest that the SH2 regions in PTPIC may interact with other cellular components to modulate its own phosphatase activity against interacting substrates. PTPase activity may thus directly link growth factor receptors and other signalling proteins through protein-tyrosine phosphorylation.
C1 MCGILL UNIV,MONTREAL H3A 2B2,QUEBEC,CANADA.
   ROYAL VICTORIA HOSP,DEPT MED,POLYPEPTIDE HORMONE LAB,MONTREAL H3A 2B2,QUEBEC,CANADA.
C3 McGill University; Royal Victoria Hospital
RP SHEN, SH (corresponding author), NATL RES COUNCIL CANADA,BIOTECHNOL RES INST,MOLEC GENET SECT,6100 ROYALMOUNT AVE,MONTREAL H4P 2R2,QUEBEC,CANADA.
NR 30
TC 423
Z9 455
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 736
EP 739
DI 10.1038/352736a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400066
PM 1652101
DA 2026-03-10
ER

PT J
AU MAGALHAES, JA
   BORUCKI, WJ
AF MAGALHAES, JA
   BORUCKI, WJ
TI SPATIAL-DISTRIBUTION OF VISIBLE LIGHTNING ON JUPITER
SO NATURE
LA English
DT Article
ID electrostatic discharges; jovian atmosphere; voyager-1; venus
AB SPACECRAFT observations have provided evidence for the existence of lightning on Venus 1-3, Jupiter 4,5, Saturn 6,7 and Uranus 8.  Little is known, however, about the global distribution of lightning on these planets because of the limited spatial resolution and areal coverage of these previous detections, which have principally involved radio-frequency measurements.  Two long-exposure images obtained by the Voyager 1 spacecraft of a small area on the nightside of Jupiter have provided the only previously studied imaging observations of lightning on another planet9,10.  Here we present an analysis of all suitable Voyager images of Jupiter and evaluate the horizontal spatial distribution of visible lightning over most of one hemisphere.  Essentially all the detectable activity is confined to very narrow latitude bands at 13.5-degrees-N and 49-degrees-N.  The active regions at 49-degrees-N are the brightest, most numerous and periodic in longitude.  Activity at this latitude is long-lived and is most likely associated with moist convective regions deep in Jupiter's atmosphere.  The longitudinal periodicity of the lightning storms may represent the effects of a planetary scale atmospheric wave trapped at the depth of the moist convection 11,12.
C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035.
C3 National Aeronautics & Space Administration (NASA); NASA Ames Research Center
RP MAGALHAES, JA (corresponding author), STANFORD UNIV,CTR RADAR ASTRON,223 DURAND BLDG,STANFORD,CA 94305, USA.
NR 26
TC 28
Z9 29
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 311
EP 313
DI 10.1038/349311a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100044
DA 2026-03-10
ER

PT J
AU SAUER, F
   JACKLE, H
AF SAUER, F
   JACKLE, H
TI CONCENTRATION-DEPENDENT TRANSCRIPTIONAL ACTIVATION OR REPRESSION BY KRUPPEL FROM A SINGLE BINDING-SITE
SO NATURE
LA English
DT Article
ID alcohol-dehydrogenase gene; early drosophila embryo; arac protein; hunchback; products; knirps; expression; promoters; pattern; region
AB ONE of the gap class of segmentation genes 1, Kruppel (Kr), is required for normal thorax and abdominal development of the Drosophila embryo.  Its gene product, a zinc-finger type protein 2, forms a bell-shape concentration gradient in a central position of the blastoderm 3-6.  Genetic and molecular studies suggested that the Kr protein (KR) may act both as a positive and as a negative regulator of transcription on several other genes 3-9 of the zygotic segmentation hierarchy 1.  We have examined the regulatory potential of Kr by a series of cotransfection experiments in the Drosophila Schneider cell line system.  Different doses of Kr expression plasmid were tested for their ability to drive reporter gene expression mediated by a single 11-base pair KR in vitro binding site common to several putative Kr target genes 4-6,8-10.  Our results show that low amounts of Kr expression plasmid lead to transcriptional activation, whereas high amounts result in repression. Distinct portions of KR other than the DNA-binding domain are required for gene activation and repression, suggesting that KR itself can act as a concentration-dependent positive and negative regulator of transcription.
RP SAUER, F (corresponding author), MAX PLANCK INST BIOPHYS CHEM,MOLEK ENTWICKLUNGSBIOL ABT,FASSBERG,W-3400 GOTTINGEN,GERMANY.
NR 32
TC 146
Z9 159
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 563
EP 566
DI 10.1038/353563a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300069
PM 1922363
DA 2026-03-10
ER

PT J
AU GODFRAY, HCJ
AF GODFRAY, HCJ
TI SIGNALING OF NEED BY OFFSPRING TO THEIR PARENTS
SO NATURE
LA English
DT Article
ID conflict; selection; behavior; models
AB THE young of birds and mammals often solicit food from their parents in ways that appear to be costly and to reduce their fitness 1,2. Thus birds in the nest beg vigorously for food, incurring energetic costs and possibly attracting predators 3; the behaviour of young mammals requiring to suckle (bleating or crying, for example) similarly appears costly 1,2. If solicitation is a means by which the young communicate need to their parents, why has a less expensive form of communication not evolved 4? An answer to this question is provided by the theory of parent-offspring conflict: natural selection acting on genes expressed in the young will lead to greater demands for parental resources than is optimal for the parent 1,5. The accurate communication of offspring need is evolutionarily unstable as offspring will be selected to demand extra resources. Models of parent-offspring conflict have shown that an evolutionarily stable equilibrium can exist at which an offspring solicits resources in a way that reduces its fitness, and a parent provides extra resources to prevent further expensive solicitation 6-11. I present an alternative explanation for costly solicitation by showing that the level of offspring solicitation can be a true reflection of offspring need as long as solicitation is costly and the benefits of extra resources increase with need. My analysis suggests that the parent normally allocates resources using accurate information about the condition of the young. The requirement that the signalling system is costly is a direct consequence of the potential for parent-offspring conflict.
C1 UNIV LONDON IMPERIAL COLL SCI & TECHNOL, NERC, CTR POPULAT BIOL, ASCOT SL5 7PY, BERKS, ENGLAND.
C3 UK Research & Innovation (UKRI); Natural Environment Research Council (NERC); Imperial College London
RP GODFRAY, HCJ (corresponding author), UNIV LONDON IMPERIAL COLL SCI & TECHNOL, DEPT BIOL, SILWOOD PK, ASCOT SL5 7PY, BERKS, ENGLAND.
NR 25
TC 547
Z9 587
U1 0
U2 125
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 328
EP 330
DI 10.1038/352328a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900068
DA 2026-03-10
ER

PT J
AU DEFEOJONES, D
   HUANG, PS
   JONES, RE
   HASKELL, KM
   VUOCOLO, GA
   HANOBIK, MG
   HUBER, HE
   OLIFF, A
AF DEFEOJONES, D
   HUANG, PS
   JONES, RE
   HASKELL, KM
   VUOCOLO, GA
   HANOBIK, MG
   HUBER, HE
   OLIFF, A
TI CLONING OF CDNAS FOR CELLULAR PROTEINS THAT BIND TO THE RETINOBLASTOMA GENE-PRODUCT
SO NATURE
LA English
DT Article
ID large t-antigen; adenovirus e1a proteins; susceptibility gene; mutational analysis; sv40; identification; transformation; sequence; complex; region
AB THE E7 transforming protein of human papilloma virus-16 binds to the retinoblastoma gene product (pRb) 1,2 through a nine-amino-acid segment of E7 (21-29) 3-5. This segment of E7 is homologous to the pRb-binding domains of the simian virus 40 large T and adenovirus E1A transforming proteins 6-9. Each of these viral transforming proteins bind to the same region of pRb 10-11. To isolate cellular proteins that interact with this viral protein-binding domain on pRb 12,13, we used recombinant pRb to screen a human complementary DNA expression library. Two cDNAs were isolated that encode retinoblastoma binding proteins (RBP-1 and RBP-2). We report here that these RBP genes exist in separate loci and produce discrete messenger RNAs. The predicted amino-acid sequence of these genes showed no homology to known proteins, but both RBPs contain the pRb binding motif conserved between E7, large T and E1A 14. In vitro expression of the RBP cDNAs yielded proteins that specifically bound to pRb. Recombinant E7 protein, the E7 21-29 peptide and the homologous RBP-L peptide inhibited RBP-pRb binding. Mutations introduced into the putative pRb-binding segment in RBP-1 impaired its binding activity. These studies indicate that the cellular RBP-1, RBP-2 and viral E7 proteins interact with pRb through similar domains.
C1 MERCK SHARP & DOHME LTD,DEPT CANC RES,W POINT,PA 19486.
C3 Merck & Company
NR 26
TC 315
Z9 360
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 251
EP 254
DI 10.1038/352251a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500070
PM 1857421
DA 2026-03-10
ER

PT J
AU SHIMIZU, Y
   SHAW, S
   GRABER, N
   GOPAL, TV
   HORGAN, KJ
   VANSEVENTER, GA
   NEWMAN, W
AF SHIMIZU, Y
   SHAW, S
   GRABER, N
   GOPAL, TV
   HORGAN, KJ
   VANSEVENTER, GA
   NEWMAN, W
TI ACTIVATION-INDEPENDENT BINDING OF HUMAN-MEMORY T-CELLS TO ADHESION MOLECULE ELAM-1
SO NATURE
LA English
DT Article
ID helper-inducer; endothelial-cells; lymphocytes; receptor; proteins; lfa-1; adhesiveness; icam-1
AB THE induction of an ensemble of adhesion molecules on endothelial cells by inflammatory cytokines is likely to be crucial to the differential migration of T-lymphocyte subsets into inflammatory sites.  Two molecular pathways involving the VLA-4 and LFA-1 integrins are known to mediate T-cell adhesion to activated endothelium 1-4.  Here we show that a third pathway involving the rapidly inducible endothelial cell-surface adhesion molecule ELAM-1 (refs 5, 6) contributes to the binding of resting CD4+ T cells to IL-1-induced human endothelial cells.  All three pathways contribute to the greater adhesion to endothelium of memory T cells than naive T cells.  There are two unique features of T-cell adhesion to purified ELAM-1:  first, ELAM-1 exclusively mediates adhesion of memory T cells; second, memory T-cell binding to ELAM-1 is independent of acute activation events that regulate integrin-mediated adhesion 7,8.  Thus, ELAM-1 may be of primary importance in the initial attachment of memory T cells to inflamed endothelium in vivo and to the preferential migration of memory T cells into tissue and inflammatory sites.
C1 OTSUKA AMER PHARMACEUT INC,DEPT IMMUNOL,ROCKVILLE,MD 20850.
   OTSUKA AMER PHARMACEUT INC,DEPT MOLEC BIOL,ROCKVILLE,MD 20850.
C3 Otsuka Pharmaceutical; Otsuka America Pharmaceutical, Inc.; Otsuka Pharmaceutical; Otsuka America Pharmaceutical, Inc.
RP SHIMIZU, Y (corresponding author), NCI,EXPTL IMMUNOL BRANCH,BETHESDA,MD 20892, USA.
NR 34
TC 396
Z9 419
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 799
EP 802
DI 10.1038/349799a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600059
PM 1705667
DA 2026-03-10
ER

PT J
AU TRENT, JD
   NIMMESGERN, E
   WALL, JS
   HARTL, FU
   HORWICH, AL
AF TRENT, JD
   NIMMESGERN, E
   WALL, JS
   HARTL, FU
   HORWICH, AL
TI A MOLECULAR CHAPERONE FROM A THERMOPHILIC ARCHAEBACTERIUM IS RELATED TO THE EUKARYOTIC PROTEIN T-COMPLEX POLYPEPTIDE-1
SO NATURE
LA English
DT Article
ID ribulose bisphosphate carboxylase; escherichia-coli; heat-shock; ribulosebisphosphate-carboxylase; mitochondrial protein; atp hydrolysis; gene; cloning; purification; sequence
AB THERE is evidence to suggest that components of archaebacteria are evolutionarily related to cognates in the eukaryotic cytosol 1-7. We postulated that the major heat-shock protein of the thermophilic archaebacterium, Sulfolobus shibatae, is a molecular chaperone and that it is related to an as-yet unidentified chaperone component in the eukaryotic cytosol. Acquired thermotolerance in S. shibatae correlates with the predominant synthesis of this already abundant protein, referred to as thermophilic factor 55 (TF55; ref. 8). TF55 is a homo-oligomeric complex of two stacked 9-membered rings, closely resembling the 7-membered-ring complexes of the chaperonins, groEL, hsp60 and Rubisco-binding protein 9-15. The TF55 complex binds unfolded polypeptides in vitro and has ATPase activity-features consistent with its being a molecular chaperone 16,17. The primary structure of TF55, however, is not significantly related to the chaperonins. On the other hand, it is highly homologous (36-40% identity) to a ubiquitous eukaryotic protein, t-complex polypeptide-1 (TCP1; refs 18-20). In Saccharomyces cerevisiae, TCP1 is an essential protein that may play a part in mitotic spindle formation 21. We suggest that TF55 in archaebacteria and TCP1 in the eukaryotic cytosol are members of a new class of molecular chaperones.
C1 YALE UNIV,SCH MED,DEPT GENET,NEW HAVEN,CT 06510.
   SLOAN KETTERING MEM CANC CTR,ROCKEFELLER RES LAB,CELLULAR BIOCHEM & BIOPHYS PROGRAM,NEW YORK,NY 10021.
   BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973.
C3 Yale University; Memorial Sloan Kettering Cancer Center; United States Department of Energy (DOE); Brookhaven National Laboratory
RP TRENT, JD (corresponding author), YALE UNIV,SCH MED,HOWARD HUGHES MED INST,333 CEDAR ST,NEW HAVEN,CT 06510, USA.
NR 43
TC 297
Z9 320
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 490
EP 493
DI 10.1038/354490a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800064
PM 1836250
DA 2026-03-10
ER

PT J
AU JIN, LP
AF JIN, LP
TI CONSTRAINTS ON R-PROCESS NUCLEOSYNTHESIS IN ACCRETION DISKS
SO NATURE
LA English
DT Article
ID black-holes; emission; origin; tori; jets
AB IT has been suggested 1 that matter in accretion disks around compact objects such as black holes or neutron stars, which appear to be responsible for galactic X-ray sources, may experience ideal conditions for classical rapid neutron-capture ('r-process') nucleosynthesis 2.  Systems in which accretion drives an outflow from a region near the compact object might thereby enrich the interstellar medium in r-process elements, such as europium.  Here I present a more detailed assessment of the efficacy of this mechanism for the r-process.  By considering the constraints imposed by typical accretion-disk conditions, I conclude that r-process elements are unlikely to have been made this way, largely because the total production is too low, by a factor of approximately 10(5), to explain the observed abundances.
C1 UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712.
C3 University of Texas System; University of Texas Austin
NR 14
TC 0
Z9 0
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 403
EP 404
DI 10.1038/350403a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200041
DA 2026-03-10
ER

PT J
AU SU, WJ
   DZIEWONSKI, AM
AF SU, WJ
   DZIEWONSKI, AM
TI PREDOMINANCE OF LONG-WAVELENGTH HETEROGENEITY IN THE MANTLE
SO NATURE
LA English
DT Article
ID aspherical earth structure; 3-dimensional structure; velocity; convection; topography; inversion; spectra
AB Analysis of travel-time anomalies of long-period shear waves recorded by the Global Digital Seismographic Network indicates that mantle heterogeneities, which probably reflect patterns of mantle convection, occur most prominently on length scales greater than about 6,000 km, when projected onto a two-dimensional map at the Earth's surface.  Models of mantle convection will need to be able to produce a similar power spectrum.
RP SU, WJ (corresponding author), HARVARD UNIV,DEPT EARTH & PLANETARY SCI,CAMBRIDGE,MA 02138, USA.
NR 35
TC 179
Z9 186
U1 1
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 121
EP 126
DI 10.1038/352121a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700044
DA 2026-03-10
ER

PT J
AU GOTOH, Y
   NISHIDA, E
   MATSUDA, S
   SHIINA, N
   KOSAKO, H
   SHIOKAWA, K
   AKIYAMA, T
   OHTA, K
   SAKAI, H
AF GOTOH, Y
   NISHIDA, E
   MATSUDA, S
   SHIINA, N
   KOSAKO, H
   SHIOKAWA, K
   AKIYAMA, T
   OHTA, K
   SAKAI, H
TI INVITRO EFFECTS ON MICROTUBULE DYNAMICS OF PURIFIED XENOPUS M-PHASE-ACTIVATED MAP KINASE
SO NATURE
LA English
DT Article
ID serine-threonine kinase; protein-kinase; phosphorylation; insulin; oocytes; eggs; centrosm; maturation; tyrosine; extracts
AB THE protein kinase MAP kinase, also called MAP2 kinase, is a serine/threonine kinase whose activation and phosphorylation are induced by a variety of mitogens 1-6, and which is thought to have a critical role in a network of protein kinases in mitogenic signal transduction 1-7.  A burst in kinase activation 8,9 and protein phosphorylation 10 may also be important in triggering the dramatic reorganization of the cell during the transition from interphase to mitosis.  The interphase-metaphase transition of microtubule arrays is under the control of p34cd2 kinase 11, a central control element in the G2-M transition of the cell cycle 12.  Here we show that a Xenopus kinase, closely related to the mitogen-activated mammalian MAP kinase, is phosphorylated and activated during M phase of meiotic and mitotic cell cycles, and that the interphase-metaphase transition of microtubule arrays can be induced by the addition of purified Xenous M phase-activated MAP kinase or mammalian mitogen-activated MAP kinase to interphase extracts in vitro.
C1 UNIV TOKYO,FAC SCI,DEPT BIOPHYS & BIOCHEM,TOKYO 113,JAPAN.
   UNIV TOKYO,FAC SCI,INST ZOOL,TOKYO 113,JAPAN.
   OSAKA UNIV,MICROBIAL DIS RES INST,SUITA,OSAKA 565,JAPAN.
C3 University of Tokyo; University of Tokyo; University of Osaka
NR 26
TC 424
Z9 436
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 251
EP 254
DI 10.1038/349251a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900060
PM 1702878
DA 2026-03-10
ER

PT J
AU BREDT, DS
   HWANG, PM
   GLATT, CE
   LOWENSTEIN, C
   REED, RR
   SNYDER, SH
AF BREDT, DS
   HWANG, PM
   GLATT, CE
   LOWENSTEIN, C
   REED, RR
   SNYDER, SH
TI CLONED AND EXPRESSED NITRIC-OXIDE SYNTHASE STRUCTURALLY RESEMBLES CYTOCHROME-P-450 REDUCTASE
SO NATURE
LA English
DT Article
ID adenine-dinucleotide-phosphate; rat anococcygeus muscle; monomethyl-l-arginine; nadph-cytochrome-p450 reductase; macrophage oxidation; nucleotide-sequence; guanylate-cyclase; brain; neurons; cells
AB Nitric oxide is a messenger molecule, mediating the effect of endothelium-derived relaxing factor in blood vessels and the cytotoxic actions of macrophages, and playing a part in neuronal communication in the brain. Cloning of a complementary DNA for brain nitric oxide synthase reveals recognition sites for NADPH, FAD, flavin mononucleotide and calmodulin as well as phosphorylation sites, indicating that the synthase is regulated by many different factors. The only known mammalian enzyme with close homology is cytochrome P-450 reductase.
C1 JOHNS HOPKINS MED INST,DEPT NEUROSCI,725 N WOLFE ST,BALTIMORE,MD 21205.
   JOHNS HOPKINS MED INST,DEPT PHARMACOL & MOLEC SCI,BALTIMORE,MD 21205.
   JOHNS HOPKINS MED INST,DEPT PSYCHIAT & BEHAV SCI,BALTIMORE,MD 21205.
   JOHNS HOPKINS UNIV,SCH MED,HOWARD HUGHES MED INST,DEPT MOLEC BIOL & GENET,BALTIMORE,MD 21205.
C3 Johns Hopkins University; Johns Hopkins Medicine; Johns Hopkins University; Johns Hopkins Medicine; Johns Hopkins University; Johns Hopkins Medicine; Howard Hughes Medical Institute; Johns Hopkins University
NR 48
TC 2339
Z9 2524
U1 1
U2 93
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 714
EP 718
DI 10.1038/351714a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100053
PM 1712077
DA 2026-03-10
ER

PT J
AU DRISCOLL, M
   CHALFIE, M
AF DRISCOLL, M
   CHALFIE, M
TI THE MEC-4 GENE IS A MEMBER OF A FAMILY OF CAENORHABDITIS-ELEGANS GENES THAT CAN MUTATE TO INDUCE NEURONAL DEGENERATION
SO NATURE
LA English
DT Article
ID transposable element; cdna sequence; rat-brain; protein; channel; receptor; mouse; transformation; activation; membrane
AB Three dominant mutations of mec-4, a gene needed for mechanosensation, cause the touch-receptor neurons of Caenorhabditis elegans to degenerate.  With deg-1, another C. elegans gene that can mutate to induce neuronal degeneration and that is similar in sequence, mec-4 defines a new gene family.  Cross-hybridizing sequences are detectable in other species, raising the possibility that degenerative conditions in other organisms may be caused by mutations in similar genes.  All three dominant mec-4 mutations affect the same amino acid.  Effects of amino-acid substitutions at this position suggest that steric hindrance may induce the degenerative state.
RP DRISCOLL, M (corresponding author), COLUMBIA UNIV,DEPT BIOL SCI,1012 SHERMAN FAIRCHILD CTR,NEW YORK,NY 10027, USA.
NR 44
TC 484
Z9 556
U1 1
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 588
EP 593
DI 10.1038/349588a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000051
PM 1672038
DA 2026-03-10
ER

PT J
AU PIRCHER, H
   ROHRER, UH
   MOSKOPHIDIS, D
   ZINKERNAGEL, RM
   HENGARTNER, H
AF PIRCHER, H
   ROHRER, UH
   MOSKOPHIDIS, D
   ZINKERNAGEL, RM
   HENGARTNER, H
TI LOWER RECEPTOR AVIDITY REQUIRED FOR THYMIC CLONAL DELETION THAN FOR EFFECTOR T-CELL FUNCTION
SO NATURE
LA English
DT Article
ID bone-marrow chimeras; transgenic mice; antigen receptor; tolerance; selection; antibody; complex; anergy; genes
AB CLONAL deletion in the thymus plays a major part in T-cell tolerance to self antigens 1-3. But the mechanism of negative selection, its fine specificity and the threshold of affinity and avidity remains unknown. We have now examined these aspects of negative selection with mice expressing a transgenic T-cell receptor with specificity for lymphocytic choriomeningitis virus (LCMV) glycoprotein in association with the class I H-2D(b) molecule. These mice were rendered tolerant to LCMV by neonatal infection with mutant LCMVs bearing point mutations in the T-cell epitope recognized by the transgenic T-cell receptor (ref. 4). Variant LCMVs were also tested for their ability to elicit antiviral responses in transgenic mice in vivo and in vitro. Comparison in vivo revealed that a low-avidity receptor interaction, which was unable to induce effector T cells in the periphery, was still sufficient for clonal deletion in the thymus.
RP PIRCHER, H (corresponding author), UNIV HOSP ZURICH, INST PATHOL, CH-8091 ZURICH, SWITZERLAND.
NR 18
TC 269
Z9 284
U1 0
U2 4
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 482
EP 485
DI 10.1038/351482a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800056
PM 1710780
DA 2026-03-10
ER

PT J
AU KLEIN, J
   PERAHIA, D
   WARBURG, S
AF KLEIN, J
   PERAHIA, D
   WARBURG, S
TI FORCES BETWEEN POLYMER-BEARING SURFACES UNDERGOING SHEAR
SO NATURE
LA English
DT Article
ID layers; interface; solvents; chains; films
AB ADSORBED or grafted polymers are used to control phenomena such as colloidal stability, fluid flow and the tribological properties of surfaces.  Forces between polymer-bearing surfaces have been studied comprehensively over the past decade 1-10, but little is known about such forces in shear.  These are intimately related to the dynamic as well as the equilibrium properties of the surface-attached chains.  We have constructed a device that measures directly the forces that act between surfaces bearing polymer layers in a liquid medium as they slide past each other.  For the case of mica sheets bearing end-grafted chains of polystyrene in toluene (a good solvent), we find that, as the surfaces move parallel to each other, there is a marked change in the normal forces between them.  These become increasingly repulsive at higher velocities.  The effect occurs only above certain critical shear rates, probably related to relaxation dynamics of the end-grafted chains themselves.  Our findings have direct implications for the properties of polymeric lubricants, and for the rheological behaviour both of stabilized dispersions and of multi-phase polymeric systems.
RP KLEIN, J (corresponding author), WEIZMANN INST SCI,POLYMER RES DEPT,IL-76100 REHOVOT,ISRAEL.
NR 20
TC 310
Z9 343
U1 1
U2 66
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 143
EP 145
DI 10.1038/352143a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700051
DA 2026-03-10
ER

PT J
AU BROWNING, KA
   ALLAM, RJ
   BALLARD, SP
   BARNES, RTH
   BENNETTS, DA
   MARYON, RH
   MASON, PJ
   MCKENNA, D
   MITCHELL, JFB
   SENIOR, CA
   SLINGO, A
   SMITH, FB
AF BROWNING, KA
   ALLAM, RJ
   BALLARD, SP
   BARNES, RTH
   BENNETTS, DA
   MARYON, RH
   MASON, PJ
   MCKENNA, D
   MITCHELL, JFB
   SENIOR, CA
   SLINGO, A
   SMITH, FB
TI ENVIRONMENTAL-EFFECTS FROM BURNING OIL-WELLS IN KUWAIT
SO NATURE
LA English
DT Article
ID atmospheric smoke; nuclear winter; model; war
AB Model calculations, constrained by satellite observations, indicate that most of the smoke from the oil fires in Kuwait will remain in the lowest few kilometres of the troposphere.  Beneath the plume there is a severe reduction in daylight, and a daytime temperature drop of approximately 10-degrees-C within approximately 200 km of the source.  Episodic events of acid rain and photochemical smog will occur within approximately 1,000-2,000 km of Kuwait.  But changes in the Asian summer monsoon are unlikely to exceed the natural interannual variability and stratospheric ozone concentrations are unlikely to be affected.
RP BROWNING, KA (corresponding author), METEOROL OFF,LONDON RD,BRACKNELL RB12 2SZ,BERKS,ENGLAND.
NR 22
TC 57
Z9 59
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 363
EP 367
DI 10.1038/351363a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600045
DA 2026-03-10
ER

PT J
AU MASU, M
   TANABE, Y
   TSUCHIDA, K
   SHIGEMOTO, R
   NAKANISHI, S
AF MASU, M
   TANABE, Y
   TSUCHIDA, K
   SHIGEMOTO, R
   NAKANISHI, S
TI SEQUENCE AND EXPRESSION OF A METABOTROPIC GLUTAMATE RECEPTOR
SO NATURE
LA English
DT Article
ID long-term potentiation; inositol phospholipid-metabolism; functional expression; xenopus oocytes; g-protein; cloning; member; family; sites; cdna
AB The complementary DNA of a metabotropic glutamate receptor coupled to inositol phosphate/Ca2+ signal transduction has been cloned and characterized.  This receptor shows no sequence similarity to conventional G protein-coupled receptors and has a unique structure with large hydrophilic sequences at both sides of seven putative membrane-spanning domains.  Abundant expression of this messenger RNA is observed in neuronal cells in hippocampal dentate gyrus and CA2-3 and in cerebellar Purkinje cells, suggesting the importance of this receptor in specific hippocampal and cerebellar functions.
C1 KYOTO UNIV,FAC MED,INST IMMUNOL,KYOTO 606,JAPAN.
   KYOTO UNIV,FAC MED,DEPT MORPHOL BRAIN SCI,KYOTO 606,JAPAN.
C3 Kyoto University; Kyoto University
NR 36
TC 1090
Z9 1212
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 760
EP 765
DI 10.1038/349760a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600045
PM 1847995
DA 2026-03-10
ER

PT J
AU RANGANATHAN, R
   HARRIS, GL
   STEVENS, CF
   ZUKER, CS
AF RANGANATHAN, R
   HARRIS, GL
   STEVENS, CF
   ZUKER, CS
TI A DROSOPHILA MUTANT DEFECTIVE IN EXTRACELLULAR CALCIUM-DEPENDENT PHOTORECEPTOR DEACTIVATION AND RAPID DESENSITIZATION
SO NATURE
LA English
DT Article
AB CALCIUM is involved in the adaptation of vertebrate photoreceptors to light 1,2 and may have a similar role in invertebrate phototransduction 3,4. But the molecular mechanisms mediating this stimulus-dependent regulation are not well understood in any G protein-coupled transduction system. We have developed a preparation of isolated Drosophila photoreceptors that has allowed us to carry out an electrophysiological characterization of the light-activated response in these sensory neurons using patch-clamp techniques. We report here that extracellular calcium entering through the light-activated conductance is a key regulator of both the activation and deactivation phases of the phototransduction cascade, and that inaC mutant photoreceptors 5 are specifically defective in the calcium-dependent deactivation mechanism. These data suggest that the light-dependent calcium influx inactivates this cascade through a biochemical pathway that requires the inaC gene product, and that this mechanism represents a molecular basis for stimulus-dependent regulation of visual transduction in Drosophila photoreceptors.
C1 UNIV CALIF SAN DIEGO, HOWARD HUGHES MED INST, LA JOLLA, CA 92093 USA.
   UNIV CALIF SAN DIEGO, DEPT BIOL, LA JOLLA, CA 92093 USA.
   UNIV CALIF SAN DIEGO, DEPT NEUROSCI, LA JOLLA, CA 92093 USA.
   SALK INST BIOL STUDIES, LA JOLLA, CA 92093 USA.
   SAN DIEGO STATE UNIV, DEPT BIOL, SAN DIEGO, CA 92182 USA.
   SAN DIEGO STATE UNIV, INST MOLEC BIOL, SAN DIEGO, CA 92182 USA.
C3 University of California System; University of California San Diego; Howard Hughes Medical Institute; University of California System; University of California San Diego; University of California System; University of California San Diego; Salk Institute; California State University System; San Diego State University; California State University System; San Diego State University
NR 28
TC 166
Z9 174
U1 0
U2 7
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 230
EP 232
DI 10.1038/354230a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800049
PM 1961249
DA 2026-03-10
ER

PT J
AU DUNDERDALE, HJ
   BENSON, FE
   PARSONS, CA
   SHARPLES, GJ
   LLOYD, RG
   WEST, SC
AF DUNDERDALE, HJ
   BENSON, FE
   PARSONS, CA
   SHARPLES, GJ
   LLOYD, RG
   WEST, SC
TI FORMATION AND RESOLUTION OF RECOMBINATION INTERMEDIATES BY ESCHERICHIA-COLI RECA AND RUVC PROTEINS
SO NATURE
LA English
DT Article
ID homologous dna-sequences; endonuclease-vii cleaves; escherichia-coli; holliday structures; strand exchange; genetic-recombination; enzymatic formation; k-12 reveals; repair; junctions
AB The recombination of DNA molecules has been reconstituted in vitro using two purified enzymes from Escherichia coli. RecA protein catalyses homologous pairing and strand exchange reactions to form intermediate DNA structures that are acted upon by RuvC. The newly identified RuvC protein resolves the intermediates by specific endonucleolytic cleavage to produce recombinant DNA molecules.
C1 IMPERIAL CANC RES FUND,CLARE HALL LABS,S MIMMS EN6 3LD,HERTS,ENGLAND.
   UNIV NOTTINGHAM,QUEENS MED CTR,DEPT GENET,NOTTINGHAM NG7 2UH,ENGLAND.
C3 University of Nottingham
FU Wellcome Trust Funding Source: Medline
NR 45
TC 225
Z9 252
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 506
EP 510
DI 10.1038/354506a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100008
PM 1758493
DA 2026-03-10
ER

PT J
AU HOLZBAUR, ELF
   HAMMARBACK, JA
   PASCHAL, BM
   KRAVIT, NG
   PFISTER, KK
   VALLEE, RB
AF HOLZBAUR, ELF
   HAMMARBACK, JA
   PASCHAL, BM
   KRAVIT, NG
   PFISTER, KK
   VALLEE, RB
TI HOMOLOGY OF A 150K CYTOPLASMIC DYNEIN-ASSOCIATED POLYPEPTIDE WITH THE DROSOPHILA GENE GLUED
SO NATURE
LA English
DT Article
ID microtubule-associated protein; retrograde axonal-transport; membranous organelles; sequence-analysis; melanogaster; locus; kinetochores; localization; mutations; motor
AB CYTOPLASMIC dynein is a microtubule-activated ATPase which produces force towards the minus ends of microtubules 1,2. It is thought to be responsible for retrograde axonal transport and other aspects of organelle motility 2-6 and may have a role in the poleward movement of mitotic chromosomes 7,8. Cytoplasmic dynein is an oligomeric complex of two catalytic heavy chains and a number of accessory subunits 1,9,10. We now report the cloning and sequencing of a complementary DNA for one of these species, a cytoplasmic dynein-associated polypeptide of relative molecular mass 150,000 (M(r) 150K). A full-length cDNA was found to contain an open reading frame of 4.0 kilobases, which is predicted to encode a polypeptide of M(r) 145K. It has extensive homology with the product of the Drosophila gene Glued, which encodes a polypeptide of M(r) 148K 11. The Glued mutation is dominant, with pleiotropic developmental defects in heterozygotes and an embryonic lethal phenotype in homozygotes. As dominant mutations may involve disruption of normal protein-protein interactions, the Glued mutation should provide insight into the mode of action of cytoplasmic dynein in vivo.
C1 UNIV VIRGINIA, HLTH SCI CTR, DEPT ANAT & CELL BIOL, CHARLOTTESVILLE, VA 22903 USA.
C3 University of Virginia
RP HOLZBAUR, ELF (corresponding author), WORCESTER FDN EXPTL BIOL INC, SHREWSBURY, MA 01545 USA.
NR 25
TC 176
Z9 198
U1 0
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 579
EP 583
DI 10.1038/351579a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400063
PM 1828535
DA 2026-03-10
ER

PT J
AU BANDARA, LR
   LATHANGUE, NB
AF BANDARA, LR
   LATHANGUE, NB
TI ADENOVIRUS-E1A PREVENTS THE RETINOBLASTOMA GENE-PRODUCT FROM COMPLEXING WITH A CELLULAR TRANSCRIPTION FACTOR
SO NATURE
LA English
DT Article
ID e1a proteins; differentiation; domains
AB THE transforming proteins of several DNA tumour viruses, including adenovirus E1a and simian virus 40 large T antigen, complex with the retinoblastoma (Rb) tumour-suppressor gene product 1,2. This requires regions in these viral proteins necessary for transformation and is thought to inactivate the growth-suppressing properties of the Rb protein by disrupting its interaction with cellular targets 3. Indeed, regions of Rb required to form a complex with E1a and large T antigen are often mutated in transformed cells 4. The level at which the Rb protein regulates proliferation is unknown, although one possibility is transcription. We have previously characterized a sequence-specific transcription factor, DRTF1, the activity of which is downregulated as embryonal carcinoma stem cells differentiate. DRTF1 is found in several discrete protein complexes (a, b and c) which are of different sizes but have the same DNA specificity 5,6. We now show that one of these also contains the Rb protein and, further, that the adenovirus E1a protein causes the dissociation of the Rb protein from this complex. This requires conserved regions 1 and 2 of E1a that are known to be required for efficient transformation 7. These results demonstrate that the Rb protein forms a complex with a DNA-bound transcription factor, and suggests that the Rb protein might act by regulating transcription.
RP BANDARA, LR (corresponding author), NATL INST MED RES, MRC, EUKARYOT MOLEC GENET LAB, RIDGEWAY, MILL HILL, LONDON NW7 1AA, ENGLAND.
NR 13
TC 431
Z9 476
U1 0
U2 5
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 494
EP 497
DI 10.1038/351494a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800060
PM 1710781
DA 2026-03-10
ER

PT J
AU GANNON, JV
   LANE, DP
AF GANNON, JV
   LANE, DP
TI PROTEIN-SYNTHESIS REQUIRED TO ANCHOR A MUTANT P53 PROTEIN WHICH IS TEMPERATURE-SENSITIVE FOR NUCLEAR TRANSPORT
SO NATURE
LA English
DT Article
ID transformed-cells; gene-product; mutations; expression; antigen; cancer
AB THE p53 protein is rendered temperature-sensitive by a point mutation 1. Rat cells transformed by this mutant p53 and an activated ras oncogene grow well at 37-degrees-C but cease DNA synthesis and cell division when shifted to 32-degrees-C (ref. 1).  Immunostaining demonstrates that the mutant p53 protein is in the nucleus of the arrested cells at 32-degrees-C but in the cytoplasm of the growing cells at 37-degrees-C. This is the first example of a protein which is temperature-sensitive for nuclear transport.  The translocation from cytoplasm to nucleus and vice versa occurs 6 h after temperature shift and is coincident with the inhibition of DNA synthesis; transport from cytoplasm to nucleus does not require protein synthesis.  Remarkably, inhibition of protein synthesis at 37-degrees-C also results in the rapid appearance of mutant p53 in the cell nucleus.  These results suggest the presence of a short-lived protein responsible for holding p53 in the cytoplasm at 37-degrees-C but not at 32-degrees-C.  Analysis of a non-temperature-sensitive mutant p53 protein shows that its cytoplasmic location is sensitive to protein synthesis inhibitors but not to temperature.
RP GANNON, JV (corresponding author), IMPERIAL CANC RES FUND,CLARE HALL LABS,POTTERS BAR EN6 3LD,HERTS,ENGLAND.
NR 29
TC 202
Z9 208
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 802
EP 806
DI 
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600060
PM 2000149
DA 2026-03-10
ER

PT J
AU MORIYOSHI, K
   MASU, M
   ISHII, T
   SHIGEMOTO, R
   MIZUNO, N
   NAKANISHI, S
AF MORIYOSHI, K
   MASU, M
   ISHII, T
   SHIGEMOTO, R
   MIZUNO, N
   NAKANISHI, S
TI MOLECULAR-CLONING AND CHARACTERIZATION OF THE RAT NMDA RECEPTOR
SO NATURE
LA English
DT Article
ID amino-acid receptors; glutamate receptor; xenopus oocytes; functional expression; protein-kinase; acetylcholine-receptor; brain; sequence; channel; kainate
AB A complementary DNA encoding the rat NMDA receptor has been cloned and characterized. The single protein encoded by the cDNA forms a receptor-channel complex that has electrophysiological and pharmacological properties characteristic of the NMDA receptor. This protein has a significant sequence similarity to the AMPA/kainate receptors and contains four putative transmembrane segments following a large extracellular domain.  The NMDA receptor messenger RNA is expressed in neuronal cells throughout the brain regions, particularly in the hippocampus, cerebral cortex and cerebellum.
C1 KYOTO UNIV,DEPT MORPHOL BRAIN SCI,KYOTO 606,JAPAN.
C3 Kyoto University
RP MORIYOSHI, K (corresponding author), KYOTO UNIV,FAC MED,INST IMMUNOL,KYOTO 606,JAPAN.
NR 44
TC 1744
Z9 1893
U1 1
U2 43
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 31
EP 37
DI 10.1038/354031a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900048
PM 1834949
DA 2026-03-10
ER

PT J
AU YARDLEY, B
   BOTTRELL, SH
   CLIFF, RA
AF YARDLEY, B
   BOTTRELL, SH
   CLIFF, RA
TI EVIDENCE FOR A REGIONAL-SCALE FLUID LOSS EVENT DURING MIDCRUSTAL METAMORPHISM
SO NATURE
LA English
DT Article
ID western ireland; high-pressures; temperatures; transport; connemara
AB How fluid is released from the deep crust during metamorphism remains controversial.  Whereas some authors advocate large-scale fluid fluxes due to convective circulation of metamorphic fluid 1, others consider that only one-way flow is possible 2,3.  Furthermore, some flow models imply that fluid moves across, and largely independently of, sedimentary layering 1,2, whereas many fluid-based studies find evidence for focusing of flow by particular lithologies 2,4-7.  Here we report a study of metamorphic fluid flow on a regional, rather than an outcrop scale, using a combination of field geology, petrology and theoretical and isotope geochemistry.  We identify metasomatic lithologies at the top of a dolomitic marble unit, which must have drawn in water over a kilometre scale from adjacent pelitic formations; we suggest that this flow was part of a single, major fluid loss event near the metamorphic peak. Fluid followed the metasomatic layers to structural highs where it broke out into adjacent schists to form skarns.  This fluid loss may have changed the rheology of the rock involved and terminated regional folding.
RP YARDLEY, B (corresponding author), UNIV LEEDS,DEPT EARTH SCI,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND.
NR 21
TC 35
Z9 36
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 151
EP 154
DI 10.1038/349151a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800056
DA 2026-03-10
ER

PT J
AU ROTZLER, S
   SCHRAMEK, H
   BRENNER, HR
AF ROTZLER, S
   SCHRAMEK, H
   BRENNER, HR
TI METABOLIC STABILIZATION OF END-PLATE ACETYLCHOLINE-RECEPTORS REGULATED BY CA2+ INFLUX ASSOCIATED WITH MUSCLE-ACTIVITY
SO NATURE
LA English
DT Article
ID mammalian skeletal-muscle; ca-2+ channels; calcium currents; membrane; degradation; ryanodine; cells; enantiomers; denervation; fraction
AB DURING formation of the neuromuscular junction, acetylcholine receptors in the endplate membrane become matabolically stabilized under neural control, their half-life increasing from about 1 day to about 10 days (see ref. 1 for review).  The metabolic stability of the receptors is regulated by the electrical activity induced in the muscle by innervation 2-4.  We report here that metabolic stabilization of endplate receptors but not of extrajunctional receptors can be induced in the absence of muscle activity if muscles are treated with the calcium ionophore A23187.  Acetylcholine receptor stabilization was also induced by culturing non-stimulated muscle in elevated K+ with the Ca2+ channel activator (+)-SDZ202-791.  Conversely, activity-dependent receptor stabilization is prevented in muscle stimulated in the presence of the Ca2+ channel blockers (+)-PN200-110 or D-600.  Treatment of muscles with ryanodine, which induces Ca2+ release from the sarcoplasmic reticulum in the absence of activity, does not cause stabilization of junctional receptors.  Evidently, muscle activity induces metabolic acetylcholine receptor stabilization by way of an influx of Ca2+ ions through dihydropyridine-sensitive Ca2+ channels in the endplate membrane, whereas Ca2+ released from the sarcoplasmic reticulum is ineffective in this developmental process.
C1 UNIV BASEL,DEPT PHYSIOL,VESALGASSE 1,CH-4051 BASEL,SWITZERLAND.
C3 University of Basel
NR 26
TC 60
Z9 62
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 337
EP 339
DI 10.1038/349337a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100055
PM 1846230
DA 2026-03-10
ER

PT J
AU RAMANATHAN, V
   COLLINS, W
AF RAMANATHAN, V
   COLLINS, W
TI THERMODYNAMIC REGULATION OF OCEAN WARMING BY CIRRUS CLOUDS DEDUCED FROM OBSERVATIONS OF THE 1987 EL-NINO
SO NATURE
LA English
DT Article
ID sea-surface temperature; climate feedback; circulation; convection; radiation; balance; co2
AB Observations made during the 1987 El Nino show that in the upper range of sea surface temperatures, the greenhouse effect increases with surface temperature at a rate which exceeds the rate at which radiation is being emitted from the surface.  In response to this 'super greenhouse effect', highly reflective cirrus clouds are produced which act like a thermostat, shielding the ocean from solar radiation.  The regulatory effect of these cirrus clouds may limit sea surface temperatures to less than 305 K.
C1 UNIV CALIF SAN DIEGO,CALIF SPACE INST,LA JOLLA,CA 92093.
C3 University of California System; University of California San Diego
RP RAMANATHAN, V (corresponding author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093, USA.
NR 38
TC 651
Z9 722
U1 0
U2 69
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 27
EP 32
DI 10.1038/351027a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300048
DA 2026-03-10
ER

PT J
AU TREZISE, AEO
   BUCHWALD, M
AF TREZISE, AEO
   BUCHWALD, M
TI INVIVO CELL-SPECIFIC EXPRESSION OF THE CYSTIC-FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR
SO NATURE
LA English
DT Article
ID identification; gene
AB CYSTIC fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) 1-3.  The principal manifestations of CF include increased concentration of Cl- in exocrine gland secretions 4,5, pancreatic insufficiency, chronic lung disease, intestinal blockage and malabsorption of fat 5,6, and male and female infertility 7.  Insight into the function of CFTR can be gained by correlating its cell-specific expression with the physiology of those cells and with CF pathology.  Determination of CFTR messenger RNA in rat tissues by in situ hybridization shows that it is specifically expressed in the ductal cells of the pancreas and the salivary glands.  In the intestine, decreasing gradients of expression of the CFTR gene are observed on both the crypt-villus and the proximal-distal axes.  This expression is consistent with CFTR being responsible for bidirectional Cl- transport, secretion in the intestinal crypts 8 and reabsorption in the salivary gland ducts 4, and suggests that in these tissues CFTR functions as a regulated Cl- channel.  In the lung, a broad band of hybridization includes the mucosa and submucosa of the bronchi and bronchioles.  In the testis, CFTR expression is regulated during the cycle of the seminiferous epithelium.  Post-meiotic expression is maximal in the round spermatids of stages VII and VIII, suggesting that CFTR plays a critical role in spermatogenesis and that deficiency of this function contributes to CF male infertility.
C1 HOSP SICK CHILDREN,RES INST,DEPT GENET,555 UNIV AVE,TORONTO M5G 1X8,ONTARIO,CANADA.
   UNIV TORONTO,DEPT MOLEC & MED GENET,TORONTO M5S 1A,ONTARIO,CANADA.
C3 University of Toronto; Hospital for Sick Children (SickKids); University of Toronto
NR 13
TC 330
Z9 360
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 434
EP 437
DI 10.1038/353434a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600058
PM 1716739
DA 2026-03-10
ER

PT J
AU GUAN, KL
   BROYLES, SS
   DIXON, JE
AF GUAN, KL
   BROYLES, SS
   DIXON, JE
TI A TYR SER PROTEIN PHOSPHATASE ENCODED BY VACCINIA VIRUS
SO NATURE
LA English
DT Article
ID leukocyte-common antigen; tyrosine-phosphatases; nucleotide-sequence; receptor; dephosphorylation; immunoglobulin; transcription; member; family
AB PROTEIN tyrosine phosphorylation is associated with alterations in receptor activity, cellular proliferation and modulation of the cell cycle 1,2.  Inappropriate tyrosine phosphorylation can lead to unrestrained cell growth and oncogenesis.  Enzymes important in tyrosine dephosphorylation have also been described 3,4-6.  Protein tyrosine phosphatases (PTPases) consist of two families.  There is a receptor-like family of PTPases with an extracellular domain, transmembrane-spanning region and typically two repeated phosphatase domains 7-11.  Proteins of the non-receptor-like family have a single catalytic phosphatase domain 3,12-15, show a substrate specificity for Tyr phosphate and will not hydrolyse Ser or Thr phosphate.  Here we report that the vaccinia virus genome contains an open reading frame which shares amino-acid sequence identity with the PTPases 3,12-16.  The purified protein encoded by the vaccinia virus H1 open reading frame expressed in bacteria hydrolyses substrates containing phosphotyrosine and phosphoserine.  Mutagenesis of an essential Cys in the vaccinia phosphatase abolishes catalytic activity directed towards both substrates, suggesting that hydrolysis proceeds by a common mechanism. Understanding the function of the H1-encoded protein will help to define the role of the phosphatase in viral replication and pathogenesis.
C1 PURDUE UNIV,WALTHER CANC INST,W LAFAYETTE,IN 47907.
C3 Purdue University System; Purdue University; Walther Cancer Foundation
RP GUAN, KL (corresponding author), PURDUE UNIV,DEPT BIOCHEM,W LAFAYETTE,IN 47907, USA.
NR 30
TC 397
Z9 440
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 359
EP 362
DI 10.1038/350359a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800099
PM 1848923
DA 2026-03-10
ER

PT J
AU BROWN, MG
   DRISCOLL, J
   MONACO, JJ
AF BROWN, MG
   DRISCOLL, J
   MONACO, JJ
TI STRUCTURAL AND SEROLOGICAL SIMILARITY OF MHC-LINKED LMP AND PROTEASOME (MULTICATALYTIC PROTEINASE) COMPLEXES
SO NATURE
LA English
DT Article
ID major histocompatibility complex; class-ii region; mammalian-cells; skeletal-muscle; ubiquitin; transporters; antigens; gene
AB MAJOR histocompatibility complex (MHC) class I molecules associate with peptides derived from endogenously synthesized antigens.  Cytotoxic T-lymphocytes can thus scan class I molecules and bound peptide on the surface of cells for foreign antigenic determinants.  Recent evidence 1,2 demonstrates that the products of trans-acting, non-class I genes in the class II region of the MHC are required in the class I antigen-processing pathway.   There are genes (called HAM1 and HAM2 in the mouse) in this region that encode proteins postulated to be involved in the transport of peptide fragments into the endoplasmic reticulum for association with newly synthesized class I molecules 2-5.   But, the mechanism by which such peptide fragments are produced remains a mystery.  At least two genes encoding subunits of the low-molecular mass polypeptide (LMP) complex are tightly linked to the HAM1 and HAM2 genes.  We show that the LMP complex is closely related to the proteasome (multicatalytic proteinase complex), an intracellular protein complex that has multiple proteolytic activities 6,7.  We speculate that the LMP complex may have a role in MHC class I antigen processing, and therefore that the MHC contains a cluster of genes required for distinct functions in the antigen processing pathway.
C1 HARVARD UNIV,SCH MED,DEPT CELLULAR & MOLEC PHYSIOL,BOSTON,MA 02115.
C3 Harvard University; Harvard Medical School
RP BROWN, MG (corresponding author), VIRGINIA COMMONWEALTH UNIV,MED COLL VIRGINIA,DEPT MICROBIOL & IMMUNOL,RICHMOND,VA 23298, USA.
NR 22
TC 315
Z9 332
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 355
EP 357
DI 10.1038/353355a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400062
PM 1922341
DA 2026-03-10
ER

PT J
AU HART, MJ
   EVA, A
   EVANS, T
   AARONSON, SA
   CERIONE, RA
AF HART, MJ
   EVA, A
   EVANS, T
   AARONSON, SA
   CERIONE, RA
TI CATALYSIS OF GUANINE-NUCLEOTIDE EXCHANGE ON THE CDC42HS PROTEIN BY THE DBL ONCOGENE PRODUCT
SO NATURE
LA English
DT Article
ID gtp-binding proteins; saccharomyces-cerevisiae; molecular-cloning; cell polarity; human homolog; gene; purification; cycle; g25k; identification
AB THE superfamily of low molecular mass GTP-binding proteins, for which the ras proteins are prototypes, has been implicated in the regulation of diverse biological activities including protein trafficking, secretion, and cell growth and differentiation 1-3. One member of this family, CDC42Hs (originally referred to as Gp or G25K) 4-5, seems to be the human homologue of the Saccharomyces cerevisiae cell-division-cycle protein, CDC42Sc (refs 6-9). A second S. cerevisiae protein, CDC24 (ref. 10), which is known from complementation studies to act with CDC42Sc to regulate the development of normal cell shape and the selection of nonrandom budding sites in yeast, contains a region with sequence similarity to the dbl oncogene product 11-14. Here we show that dbl specifically catalyses the dissociation of GDP from CDC42Hs and thereby qualifies as a highly selective guanine nucleotide exchange factor for the GTP-binding protein. Although guanine nucleotide exchange activities have been previously described for other members of the Ras-related GTP-binding protein family 15-17, this is the first demonstration, to our knowledge, of the involvement of a human oncogenic protein in catalysing exchange activity.
C1 CORNELL UNIV,DEPT PHARMACOL,ITHACA,NY 14853.
   NCI,CELLULAR & MOLEC BIOL LAB,BETHESDA,MD 20892.
   GENENTECH INC,DEPT CELL BIOL,S SAN FRANCISCO,CA 94080.
C3 Cornell University; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Roche Holding; Roche Holding USA; Genentech
RP HART, MJ (corresponding author), CORNELL UNIV,DEPT BIOCHEM CELLULAR & MOLEC BIOL,ITHACA,NY 14853, USA.
NR 22
TC 395
Z9 475
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 311
EP 314
DI 10.1038/354311a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400049
PM 1956381
DA 2026-03-10
ER

PT J
AU WATSON, AJ
   UPSTILLGODDARD, RC
   LISS, PS
AF WATSON, AJ
   UPSTILLGODDARD, RC
   LISS, PS
TI AIR SEA GAS-EXCHANGE IN ROUGH AND STORMY SEAS MEASURED BY A DUAL-TRACER TECHNIQUE
SO NATURE
LA English
DT Article
ID diffusion-coefficients; water; sulfur
AB The transfer of dissolved atmospheric gases across the air/sea interface is a strong function of wind speed and state of the sea surface.  The form of the dependence on wind velocities is needed to calculate oceanic sources and sinks of climatically significant gases, particularly carbon dioxide 1 and dimethylsulphide 2,3.  Previous measurements at sea have used techniques that reveal this dependence only when averaged over weeks or months 4,5, making it impossible to study the effects of high winds, which are generally episodic.  Here we report first results from the application of a tracer technique which enables accurate measurements to be made over periods of 24-72 hours, including the first determination of gas exchange in storm conditions.  Our results support the windspeed dependence suggested by Liss and Merlivat 6 on the basis of lake and wind-tunnel experiments, and are consistent with most measurements made by the radon-deficit technique.  They suggest slower rates for CO2 exchange than those obtained by C-14 budgeting, and favour recent lower estimates 1,7 of the global oceanic sink for anthropogenic CO2.
C1 UNIV E ANGLIA,SCH ENVIRONM SCI,NORWICH NR4 7TJ,NORFOLK,ENGLAND.
C3 University of East Anglia
RP WATSON, AJ (corresponding author), PLYMOUTH MARINE LAB,PROSPECT PL,PLYMOUTH PL1 3DH,ENGLAND.
NR 16
TC 214
Z9 228
U1 0
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 145
EP 147
DI 10.1038/349145a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800053
DA 2026-03-10
ER

PT J
AU KOONIN, SE
AF KOONIN, SE
TI ENVIRONMENTAL FINE-STRUCTURE IN LOW-ENERGY BETA-PARTICLE SPECTRA
SO NATURE
LA English
DT Article
ID heavy neutrinos; 17-kev neutrino; decay; search; tritium; s-35
AB SOME recent measurements of beta-decay spectra show anomalous line shapes which have been interpreted 1-5 as providing evidence for a neutrino with a mass of about 17 keV; other similar studies, however, find no anomalies 6-13. Regardless of the reason for these discrepancies, such studies require a detailed understanding (at the level of accuracy of one part per thousand) of the spectral shape and the detector response expected in the absence of any exotic phenomena. Influences on the beta decay process from outside the nucleus are of great importance in this regard, and the role of atomic screening corrections 14-16 and atomic and molecular effects on the spectrum near the end point 17 have been considered previously. These produce only smooth, monotonic distortions of the spectrum. Here I note the existence of an effect, previously overlooked, that results in an oscillatory structure in the beta spectrum. The effect is of sufficient magnitude to be relevant to searches for heavy neutrinos that involve tritium beta decay, and it may also provide a basis for studies of molecular or crystal structure, in a manner analogous to extended X-ray absorption fine structure (EXAFS).
RP KOONIN, SE (corresponding author), CALTECH,KELLOGG RADIAT LAB,PASADENA,CA 91125, USA.
NR 28
TC 44
Z9 44
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 468
EP 470
DI 10.1038/354468a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800056
DA 2026-03-10
ER

PT J
AU PHILLIPS, RE
   ROWLANDJONES, S
   NIXON, DF
   GOTCH, FM
   EDWARDS, JP
   OGUNLESI, AO
   ELVIN, JG
   ROTHBARD, JA
   BANGHAM, CRM
   RIZZA, CR
   MCMICHAEL, AJ
AF PHILLIPS, RE
   ROWLANDJONES, S
   NIXON, DF
   GOTCH, FM
   EDWARDS, JP
   OGUNLESI, AO
   ELVIN, JG
   ROTHBARD, JA
   BANGHAM, CRM
   RIZZA, CR
   MCMICHAEL, AJ
TI HUMAN-IMMUNODEFICIENCY-VIRUS GENETIC-VARIATION THAT CAN ESCAPE CYTOTOXIC T-CELL RECOGNITION
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; peripheral-blood; infected individuals; seropositive individuals; reverse-transcriptase; synthetic peptides; homosexual men; hiv-1; replication; selection
AB In a longitudinal study of HIV seropositive patients, there were fluctuations in the specificity of cytotoxic T cells for the virus. This was matched by variability in proviral gag DNA epitope sequences in the lymphocytes of these patients. Some of these viral variants are not recognized by autologous T cells. Accumulation of such mutations in T-cell antigenic targets would provide a mechanism for immune escape.
C1 IMMULOGIC, PALO ALTO, CA 94304 USA.
   CHURCHILL HOSP, OXFORD HAEMOPHILIA CTR, OXFORD OX3 7LV, ENGLAND.
RP PHILLIPS, RE (corresponding author), UNIV OXFORD, JOHN RADCLIFFE HOSP, INST MOLEC MED, MOLEC IMMUNOL GRP, OXFORD OX3 9DU, ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 43
TC 984
Z9 1065
U1 0
U2 23
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 453
EP 459
DI 10.1038/354453a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800051
PM 1721107
DA 2026-03-10
ER

PT J
AU BINGGELI, N
   CHELIKOWSKY, JR
AF BINGGELI, N
   CHELIKOWSKY, JR
TI STRUCTURAL TRANSFORMATION OF QUARTZ AT HIGH-PRESSURES
SO NATURE
LA English
DT Article
ID silica; amorphization
AB THE behaviour of alpha-quartz, one of the most common tetrahedrally coordinated silica polymorphs, at high pressures has been the subject of several experimental studies.  At room temperature, gradual pressure-induced amorphization is observed (at about 25-35 GPa) 1,2, followed at higher pressures (above 60 GPa) by a transformation to a crystalline octahedrally coordinated 'rutile-like' structure 3. The driving force for these transformations is not well understood.  We report here first-principles calculations of the electronic and structural properties of the high-pressure structure of alpha-quartz, which show a pressure-induced transformation of the oxygen sublattice to a body-centred cubic structure.  The main features of cubic packing are present at 30 GPa, and the ideal form is achieved at about 60 GPa.  The formation of the cubic sublattice facilitates structural transformations involving a change in Si coordination.  In the oxygen body-centred cubic lattice, a small displacement of Si ions along the empty channels of the structure is sufficient to transform alpha-quartz either to a structure with mixed fourfold/sixfold coordination or, for a larger silicon displacement, to a purely sixfold-coordinated structure.  This description is consistent with the evidence of intermediate crystalline phases with mixed Si coordination above the amorphization pressure in molecular-dynamics simulations 4, and can also explain the transformation to a sixfold crystalline structure at higher pressure.
C1 UNIV MINNESOTA,MINNESOTA SUPERCOMP INST,MINNEAPOLIS,MN 55455.
C3 University of Minnesota System; University of Minnesota Twin Cities
RP BINGGELI, N (corresponding author), UNIV MINNESOTA,DEPT CHEM ENGN & MAT SCI,MINNEAPOLIS,MN 55455, USA.
NR 9
TC 70
Z9 73
U1 1
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 344
EP 346
DI 10.1038/353344a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400057
DA 2026-03-10
ER

PT J
AU SHIBUKI, K
   OKADA, D
AF SHIBUKI, K
   OKADA, D
TI ENDOGENOUS NITRIC-OXIDE RELEASE REQUIRED FOR LONG-TERM SYNAPTIC DEPRESSION IN THE CEREBELLUM
SO NATURE
LA English
DT Article
ID purkinje-cells; activation; rat
AB CONJUNCTIVE stimulation of climbing and parallel fibres in the cerebellum evokes a long-term depression of parallel-fibre Purkinje-cell transmission 1,2, a phenomenon implicated as the cellular mechanism for cerebellar motor learning 3.  It is suspected that the increase in cyclic GMP concentration that occurs after activation of climbing fibres 4 is required to evoke long-term depression 3.  Excitatory amino acids are known to cause the release of nitric oxide (NO), resulting in elevation of the cGMP level in the cerebellum 5.  Here we report that endogenous NO is released after stimulation of climbing fibres, that long-term depression evoked by conjunctive stimulation of parallel and climbing fibres is blocked by haemoglobin (which strongly binds NO) or L-N(G)-monomethyl-arginine (an inhibitor of NO synthase), and that exogenous NO or cGMP can substitute for the stimulation of climbing fibres to cause long-term depression in rat cerebellar slices.  These results demonstrate that the release of endogenous NO is essential for the induction of synaptic plasticity in the cerebellum.
RP SHIBUKI, K (corresponding author), INST PHYS & CHEM RES,FRONTIER RES PROGRAM,NEURAL NETWORKS LAB,WAKO,SAITAMA 35101,JAPAN.
NR 18
TC 841
Z9 869
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 326
EP 328
DI 10.1038/349326a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100051
PM 1702879
DA 2026-03-10
ER

PT J
AU POTTS, WK
   MANNING, CJ
   WAKELAND, EK
AF POTTS, WK
   MANNING, CJ
   WAKELAND, EK
TI MATING PATTERNS IN SEMINATURAL POPULATIONS OF MICE INFLUENCED BY MHC GENOTYPE
SO NATURE
LA English
DT Article
ID major histocompatibility complex; mus-musculus; house mouse; polymorphism; loci; overdominant; preferences; recognition; selection; humans
AB BECAUSE of the central role of major histocompatibility complex (MHC) genes in immune recognition 1-3, it is often assumed that parasite-driven selection maintains the unprecedented genetic diversity of these genes 4-7.  But associations between MHC genotype and specific infectious diseases have been difficult to identify 8,9 with a few exceptions such as Marek's disease 10 and malaria 11. Alternatively, MHC-related reproductive mechanisms such as selective abortion 12-15 and mating preferences 16,17 could be responsible for the diversity. To determine both the nature and strength of selection operating on MHC genes by we have studied components of selection in seminatural populations of mice (Mus musculus domesticus). Here we assess MHC-related patterns of reproduction and early (preweaning) mortality by analysing 1,139 progeny born in nine populations, and 662 progeny from laboratory matings. Reproductive mechanisms, primarily mating preferences, result in 27% fewer MHC-homozygous offspring than expected from random mating. MHC genotype had no detectable influence on neonatal (preweaning) mortality. These mating preferences are strong enough to account for most of the MHC genetic diversity found in natural populations of Mus.
C1 UNIV WASHINGTON,DEPT PSYCHOL,SEATTLE,WA 98195.
C3 University of Washington; University of Washington Seattle
RP POTTS, WK (corresponding author), UNIV FLORIDA,DEPT PATHOL & LAB MED,MOLEC GENET LAB,GAINESVILLE,FL 32610, USA.
NR 32
TC 501
Z9 549
U1 0
U2 81
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 619
EP 621
DI 10.1038/352619a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100055
PM 1865924
DA 2026-03-10
ER

PT J
AU SPIES, T
   DEMARS, R
AF SPIES, T
   DEMARS, R
TI RESTORED EXPRESSION OF MAJOR HISTOCOMPATIBILITY CLASS-I MOLECULES BY GENE-TRANSFER OF A PUTATIVE PEPTIDE TRANSPORTER
SO NATURE
LA English
DT Article
ID hla-b antigens; lymphoblastoid cells; t-cells; mhc; complex; region; determinant; binding; protein; pathway
AB CYTOTOXIC T lymphocytes recognize antigen-derived peptides bound to major histocompatibility complex (MHC) class I molecules with which they assemble in the endoplasmic reticulum or in an undefined subcompartment 1-10.  There is genetic evidence that the peptides that are products of cytosolic protein degradation are transported into this compartment by a peptide supply factor (PSF), encoded in the MHC class II region 11.  Like the corresponding genes RING4, HAM1 and mtp1 (refs 12-14), PSF is related to the multidrug-resistance family of transporters 11 and may be a peptide pump, as translocation of peptides across membranes must occur independently of the secretory pathway 15.  There is, however, no functional evidence for this role so far.  Here we report gene transfer experiment showing that expression of PSF complementary DNA in the human lymphoblastoid cell line mutant 721.134 (refs 11, 16, 17) restores normal levels of surface HLA-A2 and -B5.  No similar effect was observed in 721.174 mutant cells, in which a homozygous deletion includes PSF among several other closely linked genes 11.  At least one of these genes may therefore also be required for PSF function.
C1 UNIV WISCONSIN,GENET LAB,MADISON,WI 53706.
C3 University of Wisconsin System; University of Wisconsin Madison
RP SPIES, T (corresponding author), HARVARD UNIV,SCH MED,DANA FARBER CANC INST,DIV TUMOR VIROL,BOSTON,MA 02115, USA.
NR 25
TC 420
Z9 461
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 323
EP 324
DI 10.1038/351323a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600063
PM 2034277
DA 2026-03-10
ER

PT J
AU VORONTSOV, SV
   BATURIN, VA
   PAMYATNYKH, AA
AF VORONTSOV, SV
   BATURIN, VA
   PAMYATNYKH, AA
TI SEISMOLOGICAL MEASUREMENT OF SOLAR HELIUM ABUNDANCE
SO NATURE
LA English
DT Article
ID stellar envelopes; equation; state; sun; models
AB The internal structure and evolution of the Sun depends on its chemical composition, particularly the helium abundance. In addition, the helium abundance in the solar envelope is thought to represent the protosolar value, making it a datum of cosmological significance. Spectroscopic measurements of the helium abundance are uncertain, and the most reliable estimates until now have come from the calibration of solar evolutionary models. The frequencies of solar acoustic oscillations are sensitive, however, to the behaviour of the speed of sound in the Sun's helium ionization zone, which allows a helioseismological determination of the helium abundance. Sound-speed inversion of helioseismological data can be used for this purpose1-3, but precise frequency measurements of high-degree oscillation modes are needed. Here we describe a new approach based on an analysis of the phase shift of acoustic waves4,5 of intermediate-degree modes. From the accurate intermediate-mode data now available6, we obtain a helium mass fraction Y = 0.25 +/- 0.01 in the solar convection zone, significantly smaller than the value Y = 0.27-0.29 predicted by recent solar evolutionary models7-9. The discrepancy indicates either that initial helium abundance was reduced in the envelope by downward diffusion9 or that the protosolar value was lower than currently accepted.
C1 PK SHTERNBERG ASTRON INST, MOSCOW 119899, USSR.
   MOSCOW ASTRON COUNCIL, MOSCOW 109017, USSR.
C3 Lomonosov Moscow State University
RP VORONTSOV, SV (corresponding author), MOSCOW PHYS EARTH INST, MOSCOW 123810, USSR.
NR 30
TC 101
Z9 101
U1 1
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 49
EP 51
DI 10.1038/349049a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100045
DA 2026-03-10
ER

PT J
AU ABRAHAM, N
   MICELI, MC
   PARNES, JR
   VEILLETTE, A
AF ABRAHAM, N
   MICELI, MC
   PARNES, JR
   VEILLETTE, A
TI ENHANCEMENT OF T-CELL RESPONSIVENESS BY THE LYMPHOCYTE-SPECIFIC TYROSINE PROTEIN-KINASE P56LCK
SO NATURE
LA English
DT Article
ID monoclonal-antibody; cd4 receptor; surface-antigens; phosphorylation; identification; association; activation; expression; domain; lines
AB LYMPHOCYTE-specific tyrosine protein kinase p56lck is physically associated with CD4 and CD8 T-cell surface molecules, suggesting that it may transduce CD4/CD8-triggered tyrosine phosphorylation signals during antigen stimulation 1,2.  Indeed, antibody-mediated aggregation of CD4 (to mimic interaction with its ligand, major histocompatibility complex (MHC) class II molecules), rapidly elevates the kinase activity of p56lck (refs 3, 4) and is associated with marked changes in tyrosine protein phosphorylation 4-6.  Genetic analyses suggest that the interaction of CD4/CD8 with p56lck results in a positive signal during antigen-induced T-cell activation 7-10.  To evaluate directly the role of p56lck in T-cell activation, we introduced a constitutively activated form of Lck protein (tyrosine 505 to phenylalanine 505 mutant; refs 11-13) in a CD4-negative, MHC-class II restricted mouse T-cell hybridoma 14.  We report here that, as for transfection of CD4 10,15,16, expression of the Lck mutant enhanced T-lymphocyte responsiveness.  The finding provides direct evidence that p56lck can positively regulate T-cell functions and that it mediates at least some of the effects of CD4 and CD8 on T-cell activation.
C1 MCGILL UNIV,CTR CANC,MONTREAL H3G 1Y6,QUEBEC,CANADA.
   MCGILL UNIV,DEPT BIOCHEM,MONTREAL H3G 1Y6,QUEBEC,CANADA.
   STANFORD UNIV,MED CTR,DEPT MED,DIV IMMUNOL & RHEUMATOL,STANFORD,CA 94305.
C3 McGill University; McGill University; Stanford University
NR 37
TC 319
Z9 336
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 62
EP 66
DI 10.1038/350062a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300065
PM 1706070
DA 2026-03-10
ER

PT J
AU RASTOGI, S
   NEWMAN, M
   KELLER, A
AF RASTOGI, S
   NEWMAN, M
   KELLER, A
TI PRESSURE-INDUCED AMORPHIZATION AND DISORDERING ON COOLING IN A CRYSTALLINE POLYMER
SO NATURE
LA English
DT Article
ID metallic amorphous state; transition; phase; ice; scattering; alpo4; glass; sni4
AB IN the Course of exploring the phase diagram of the polymer poly(4-methyl-pentene-1) as a function of temperature and pressure by in situ X-ray diffraction, we have discovered some unusual phase behaviour. The polymer, crystalline under ambient conditions, becomes amorphous reversibly on increasing pressure in two widely separated temperature regimes (approximately 20-degrees-C and approximately 200-degrees-C), the transformation occurring via a liquid-crystalline state. This suggests the possibility of 're-entrant' liquid-crystal and amorphous phases as pressure or temperature are varied. In the higher-temperature regime, the melting point shows a maximum as a function of pressure. The lower-temperature amorphous phase becomes crystalline on heating, and reverts to the glassy, disordered phase on cooling. Whereas pressure-induced amorphization has been observed previously in other systems, such as ice, silica and AlPO4, we know of no precedent for the disordering on cooling that we observe.
C1 UNIV LUCKNOW,DEPT PHYS,LUCKNOW 226007,UTTAR PRADESH,INDIA.
C3 Lucknow University
RP RASTOGI, S (corresponding author), UNIV BRISTOL,HH WILLS PHYS LAB,TYNDALL AVE,BRISTOL BS8 1TL,AVON,ENGLAND.
NR 22
TC 61
Z9 66
U1 0
U2 50
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 55
EP 57
DI 10.1038/353055a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500054
DA 2026-03-10
ER

PT J
AU JAMIESON, DJ
   RAHE, B
   PRINGLE, J
   BEGGS, JD
AF JAMIESON, DJ
   RAHE, B
   PRINGLE, J
   BEGGS, JD
TI A SUPPRESSOR OF A YEAST SPLICING MUTATION (PRP8-1) ENCODES A PUTATIVE ATP-DEPENDENT RNA HELICASE
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; nucleotide-sequence; gene region; protein; transformation
AB FIVE small nuclear RNAs (snRNAs) are required for nuclear pre-messenger RNA splicing:  U1, U2, U4, U5 and U6 1,2.  The yeast U1 and U2 snRNAs base-pair to the 5' splice site and branch-point sequences of introns respectively 1.  The role of the U5 and U4/U6 small nuclear ribonucleoprotein particles (snRNPs) is splicing is not clear, through a catalytic role for the U6 snRNA has be proposed 3.  Less is known about yeast splicing factors, but the availability of genetic techniques in Saccharomyces cerevisiae has led to the identification of mutants deficient in nuclear pre-mRNA splicing (prp2-prp27)4,5.  Several PRP genes have now been cloned and their protein products characterized. The PRP8 protein is a component of the U5 snRNP and associates with the U4/U6 snRNAs/snRNP to form a multi-snRNP particle believed to be important for spliceosome assembly 6.  We have isolated extragenic suppressors of the prp8-1 mutation of S. cerevisiae and present here the preliminary characterization of one of these suppressors, spp81.  The predicted amino-acid sequence of the SPP81 protein shows extensive similarity to a recently identified family of proteins thought to possess ATP-dependent RNA helicase activity.  The possible role of this putative helicase in nuclear pre-mRNA splicing is discussed.
C1 UNIV MICHIGAN,PROGRAM CELLULAR & MOLEC BIOL,ANN ARBOR,MI 48103.
   UNIV MICHIGAN,DEPT BIOL,ANN ARBOR,MI 48103.
C3 University of Michigan System; University of Michigan; University of Michigan System; University of Michigan
RP JAMIESON, DJ (corresponding author), UNIV EDINBURGH,INST CELL & MOLEC BIOL,KINGS BLDG,MAYFIELD RD,EDINBURGH EH9 3JR,MIDLOTHIAN,SCOTLAND.
NR 30
TC 102
Z9 109
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 715
EP 717
DI 10.1038/349715a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700054
PM 1996139
DA 2026-03-10
ER

PT J
AU COVERLEY, D
   KENNY, MK
   MUNN, M
   RUPP, WD
   LANE, DP
   WOOD, RD
AF COVERLEY, D
   KENNY, MK
   MUNN, M
   RUPP, WD
   LANE, DP
   WOOD, RD
TI REQUIREMENT FOR THE REPLICATION PROTEIN SSB IN HUMAN DNA EXCISION REPAIR
SO NATURE
LA English
DT Article
ID human cell-extracts; simian virus-40 dna; purified proteins; polymerase-delta; helicase-ii; invitro; complex; alpha
AB REPLICATION and repair are essential processes that maintain the continuity of the genetic material. Dissection of simian virus 40 (SV40) DNA replication has resulted in the identification of many eukaryotic replication proteins, but the biochemistry of the multienzyme process of DNA excision repair is less well defined. One protein that is absolutely required for semiconservative replication of SV40 DNA in vitro is human single-stranded DNA-binding protein (SSB, also called RF-A and RP-A) 1-3. SSB consists of three polypeptides of relative molecular mass 70,000, 34,000 and 13,000, and acts with T antigen and topoisomerases to unwind DNA, allowing the access of other replication proteins. Human SSB can also stimulate the activity of polymerases- alpha and delta, suggesting a further role in elongation during DNA replication 4-6. We have now found a role for human SSB in DNA excision repair using a cell-free system that can carry out nucleotide excision repair in vitro 7. Monoclonal antibodies against human SSB caused extensive inhibition of DNA repair in plasmid molecules damaged by ultraviolet light or acetylaminofluorene. Addition of purified SSB reversed this inhibition and further stimulated repair synthesis by increasing the number of repair events. These results show that a mammalian DNA replication protein is also essential for repair.
C1 YALE UNIV, SCH MED, RADIOBIOL LABS, NEW HAVEN, CT 06510 USA.
C3 Yale University
RP COVERLEY, D (corresponding author), IMPERIAL CANC RES FUND, CLARE HALL LABS, BLANCHE LANE, S MIMMS EN6 3LD, HERTS, ENGLAND.
NR 23
TC 235
Z9 249
U1 0
U2 6
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 538
EP 541
DI 10.1038/349538a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100072
PM 1992355
DA 2026-03-10
ER

PT J
AU SHINE, KP
   SINHA, A
AF SHINE, KP
   SINHA, A
TI SENSITIVITY OF THE EARTHS CLIMATE TO HEIGHT-DEPENDENT CHANGES IN THE WATER-VAPOR MIXING-RATIO
SO NATURE
LA English
DT Article
AB THE atmospheric water vapour feedback is thought to amplify the global climate response to increased concentrations of greenhouse gases 1. As the oceans and atmosphere warm, there is increased evaporation, and it is generally believed that the additional moisture then adds to the greenhouse effect by trapping more infrared radiation. Lindzen 2-4 has suggested that climate models overestimate this response; he argues that increased convective activity in a warmer climate will lead to a drying rather than a moistening of the upper troposphere (but see refs 5-7 for other views). An important part of Lindzen's argument is that it is only changes in upper tropospheric water vapour that can alter the radiative budget of the atmosphere significantly, and hence contribute to the water vapour feedback. Here we use radiative transfer calculations to show that this seems to be true if the water vapour concentration is perturbed by a constant absolute amount at all heights. But observations of the seasonal change in water vapour concentrations 6,8 suggest that the climate response to increased concentrations of greenhouse gases may be closer to a constant relative change at all heights, corresponding to much larger absolute changes in the lower troposphere. We find that the Earth's radiation budget is most sensitive to changes in lower tropospheric water vapour concentrations, when such relative perturbations are considered.
RP SHINE, KP (corresponding author), UNIV READING,DEPT METEOROL,2 EARLEY GATE,READING RG6 2AU,ENGLAND.
NR 20
TC 135
Z9 150
U1 0
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 382
EP 384
DI 10.1038/354382a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100047
DA 2026-03-10
ER

PT J
AU BROWN, CJ
   BALLABIO, A
   RUPERT, JL
   LAFRENIERE, RG
   GROMPE, M
   TONLORENZI, R
   WILLARD, HF
AF BROWN, CJ
   BALLABIO, A
   RUPERT, JL
   LAFRENIERE, RG
   GROMPE, M
   TONLORENZI, R
   WILLARD, HF
TI A GENE FROM THE REGION OF THE HUMAN X-INACTIVATION CENTER IS EXPRESSED EXCLUSIVELY FROM THE INACTIVE X-CHROMOSOME
SO NATURE
LA English
DT Article
ID controlling elements; linked gene; mouse; dna; locus; hypothesis; deletions; mutations; cells; cdna
AB X-chromosome inactivation results in the cis-limited dosage compensation of genes on one of the pair of X chromosomes in mammalian females. Although most X-linked genes are believed to be subject to inactivation, several are known to be expressed from both active and inactive X chromosomes.  Here we describe an X-linked gene with a novel expression pattern-transcript are detected only from the inactive X chromosome (X(i)) and not from the active X chromosome (X(a)).  This gene, called XIST (for X(i)-specific transcripts), is a candidate for a gene either involved in or uniquely influenced by the process of X inactivation.
C1 STANFORD UNIV,MED CTR,SCH MED,DEPT GENET,STANFORD,CA 94305.
   BAYLOR UNIV,INST MOLEC GENET,HOUSTON,TX 77030.
C3 Stanford University; Baylor College of Medicine; Baylor University
NR 41
TC 1361
Z9 1613
U1 0
U2 106
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 38
EP 44
DI 10.1038/349038a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100042
PM 1985261
DA 2026-03-10
ER

PT J
AU WICKNER, S
   HOSKINS, J
   MCKENNEY, K
AF WICKNER, S
   HOSKINS, J
   MCKENNEY, K
TI FUNCTION OF DNAJ AND DNAK AS CHAPERONES IN ORIGIN-SPECIFIC DNA-BINDING BY REPA
SO NATURE
LA English
DT Article
ID p1 plasmid replication; heat-shock proteins; escherichia-coli; gene
AB HEAT-shock proteins are normal constituents of cells whose synthesis is increased on exposure to various forms of stress.  They are interesting because of their ubiquity and high conservation during evolution.  Two families of heat-shock proteins, hsp60s and hsp70s, have been implicated in accelerating protein folding and oligomerization and also in maintaining proteins in an unfolded state, thus facilitating membrane transport 1-5.  The Escherichia coli hsp70 analogue, DnaK, and two other heat-shock proteins, DnaJ and GrpE, are required for cell viability at high temperatures and are involved in DNA replication of phage-lambda and plasmids P1 and F 6-10.  These three proteins are involved in replication in vitro of P1 DNA along with many host replication proteins and the P1 RepA initiator protein 11,12.  RepA exists in a stable protein complex with DnaJ containing a dimer each of RepA and DnaJ 11.  We report here that DnaK and DnaJ mediate an alteration in the P1 initiator protein, rendering it much more active for oriP1 DNA binding.
C1 NATL INST STAND & TECHNOL,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850.
C3 National Institute of Standards & Technology (NIST) - USA
RP WICKNER, S (corresponding author), NCI,MOLEC BIOL LAB,BETHESDA,MD 20892, USA.
NR 16
TC 204
Z9 212
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 165
EP 167
DI 10.1038/350165a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500063
PM 2005967
DA 2026-03-10
ER

PT J
AU ZELLER, E
   BERUDA, H
   KOLB, A
   BISSINGER, P
   RIEDE, J
   SCHMIDBAUR, H
AF ZELLER, E
   BERUDA, H
   KOLB, A
   BISSINGER, P
   RIEDE, J
   SCHMIDBAUR, H
TI CHANGE OF COORDINATION FROM TETRAHEDRAL GOLD AMMONIUM TO SQUARE-PYRAMIDAL GOLD ARSONIUM CATIONS
SO NATURE
LA English
DT Article
ID molecular-orbital analysis; cluster compounds; complexes; aurophilicity; chemistry
AB RECENT work 1-5 has shown that gold-based ligands in compounds of carbon and nitrogen can induce novel molecular structures with coordination numbers at C and N as high as 5 and 6.  These phenomena must be ascribed to metal-metal interactions (Au...Au), which can overrule bonding in classical configurations.  Here we describe a study of the molecular structures of tetra(auro)ammonium ((LAu)4N+) and tetra(auro)arsonium ((LAu)4As+) cations (where L is a ligand).  We find that the classical tetrahedral structure in these four-coordinate compounds is abandoned in favour of a square-pyramidal geometry once the radius of the central element is too large to allow for metal-metal bonding in a tetrahedral geometry.  Thus, whereas the nitrogen compounds adopt a tetrahedral structure, for the larger arsenic atom an arsenic-capped square of gold atoms represents a more favourable core geometry.  We have not yet been able to prepare the intermediate phosphorus compound, but we expect it also to have the square-pyramidal structure.
RP ZELLER, E (corresponding author), TECH UNIV MUNICH,INST ANORGAN CHEM,LICHTENBERGSTR 4,W-8046 GARCHING,GERMANY.
NR 27
TC 130
Z9 135
U1 0
U2 17
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 141
EP 143
DI 10.1038/352141a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700050
DA 2026-03-10
ER

PT J
AU LECHLEITER, J
   GIRARD, S
   CLAPHAM, D
   PERALTA, E
AF LECHLEITER, J
   GIRARD, S
   CLAPHAM, D
   PERALTA, E
TI SUBCELLULAR PATTERNS OF CALCIUM RELEASE DETERMINED BY G-PROTEIN-SPECIFIC RESIDUES OF MUSCARINIC RECEPTORS
SO NATURE
LA English
DT Article
ID subtypes; cell; hydrolysis
AB CALCIUM release from intracellular stores is a point of convergence for a variety of receptors involved in cell signalling 1.  Consequently, the mechanism(s) by which cells differentiate between individual receptor signals is central to transmembrane communication 2-5.  There are significant differences in timing and magnitude of Ca2+ release stimulated by the m2 and m3 muscarinic acetylcholine receptors 6-11.  The m2 receptors couple to a pertussis toxin-sensitive G protein to activate phosphatidyl inositol hydrolysis weakly and to stimulate small, delayed and oscillatory chloride currents.  In contrast, m3 receptors potently activate phosphatidyl inositol hydrolysis and stimulate large, rapid and transient chloride currents by a pertussis toxin-insensitive G protein pathway.  Using confocal microscopy, we now show that the m2- and m3-coupled Ca2+ release pathways can also be spatially distinguished.  At submaximal acetylcholine concentrations, both receptors stimulated pulses of Ca2+ release from discrete foci in random, periodic and frequently bursting patterns of activity.  But maximal stimulation of m2 receptors increased the number of focal release sites, whereas m3 receptors invariably evoked a Ca2+ wave propagating rapidly just beneath the plasma membrane surface.  Analysis of pertussis toxin sensitivity and hybrid m2-m3 muscarinic acetylcholine receptors confirmed that these Ca2+ release patterns represent distinct cell signalling pathways.
C1 HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,CAMBRIDGE,MA 02138.
C3 Harvard University
RP LECHLEITER, J (corresponding author), MAYO CLIN & MAYO FDN,DEPT PHARMACOL,200 1ST ST SW,ROCHESTER,MN 55905, USA.
NR 15
TC 155
Z9 157
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 505
EP 508
DI 10.1038/350505a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300053
PM 1849616
DA 2026-03-10
ER

PT J
AU NEE, S
   READ, AF
   GREENWOOD, JJD
   HARVEY, PH
AF NEE, S
   READ, AF
   GREENWOOD, JJD
   HARVEY, PH
TI THE RELATIONSHIP BETWEEN ABUNDANCE AND BODY SIZE IN BRITISH BIRDS
SO NATURE
LA English
DT Article
ID population-density; species number; mammals; ecology
AB THE relationship between abundance and body size is the subject of considerable debate in ecology 1-15. Several data sets spanning a large range of body sizes show linear negative relationships between abundance and weight 1-6 when these are measured on a logarithmic scale. But other studies of the abundances of species from single taxa, such as birds, which span a narrower range of body sizes reveal either little or no relationship, or a triangular relationship 9-15. Errors in estimating abundance might obscure relationships that do exist over a narrow range of body sizes. We describe here the relationship between body weight and abundance in British birds, whose population size estimates are unusually good. Abundance across all species declines with a -0.75 power of body weight, which conforms with the energetic equivalence 'rule' 2,16. There is, however, a significant positive relationship between abundance and body weight within lower taxa. Those tribes that do not share recent common ancestry with other British birds are most likely to show a positive relationship across their constituent species. We thus show that phylogenetic relatedness might be an important indicator of the structure of the relationship between body size and abundance.
C1 BRITISH TRUST ORNITHOL, THETFORD IP24 2PU, NORFOLK, ENGLAND.
C3 British Trust for Ornithology
RP NEE, S (corresponding author), UNIV OXFORD, DEPT ZOOL, AFRC, ECOL & BEHAV UNIT, S PARKS RD, OXFORD OX1 3PS, ENGLAND.
NR 28
TC 267
Z9 287
U1 0
U2 38
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 312
EP 313
DI 10.1038/351312a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600058
DA 2026-03-10
ER

PT J
AU FALK, K
   ROTZSCHKE, O
   STEVANOVIC, S
   JUNG, G
   RAMMENSEE, HG
AF FALK, K
   ROTZSCHKE, O
   STEVANOVIC, S
   JUNG, G
   RAMMENSEE, HG
TI ALLELE-SPECIFIC MOTIFS REVEALED BY SEQUENCING OF SELF-PEPTIDES ELUTED FROM MHC MOLECULES
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; major histocompatibility complex; class-i molecules; synthetic peptides; circumsporozoite protein; influenza nucleoprotein; monoclonal-antibody; immunogenic peptides; cell recognition; fine specificity
AB The crystal structures of major histocompatibility complex (MHC) molecules contain a groove occupied by heterogeneous material thought to represent peptides central to immune recognition, although until now relatively little characterization of the peptides has been possible. Exact information about the contents of MHC grooves is now provided. Moreover, each MHC class I allele has its individual rules to which peptides presented in the grove adhere.
C1 UNIV TUBINGEN, INST ORGAN CHEM, W-7400 TUBINGEN 1, GERMANY.
C3 Eberhard Karls University of Tubingen
RP RAMMENSEE, HG (corresponding author), MAX PLANCK INST BIOL, IMMUNOGENET ABT, CORRENSSTR 42, W-7400 TUBINGEN, GERMANY.
NR 47
TC 2364
Z9 2750
U1 1
U2 98
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 290
EP 296
DI 10.1038/351290a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600050
PM 1709722
DA 2026-03-10
ER

PT J
AU BLUMBERG, H
   SILVER, PA
AF BLUMBERG, H
   SILVER, PA
TI A HOMOLOG OF THE BACTERIAL HEAT-SHOCK GENE DNAJ THAT ALTERS PROTEIN SORTING IN YEAST
SO NATURE
LA English
DT Article
ID escherichia-coli; endoplasmic-reticulum; bacteriophage-lambda; replication; initiation; translocation; sequence; cells
AB HEAT-shock proteins have been implicated in assembly of protein complexes 1, correct protein folding 2 and uptake of proteins into organelles 3,4. In Escherichia coli, the heat-shock protein DnaJ and the Hsp70 homologue, DnaK, act together to disassemble a protein complex involved in bacteriophage-lambda replication 5. We report the identification of SCJ1, a gene in the yeast Saccharomyces cerevisiae that encodes a homologue of the bacterial DnaJ protein. SCJ1 was identified by a genetic screen in which increased expression of candidate genes results in missorting of a nuclear-targeted test protein. The predicted amino-acid sequence of SCJ1 is 37% identical to the entire E. coli DnaJ protein. Hybridization experiments indicate that there is a family of yeast genes related to SCJ1. These findings suggest that the Hsp70 DnaK-DnaJ interaction is general to eukaryotes.
C1 PRINCETON UNIV, DEPT MOLEC BIOL, PRINCETON, NJ 08544 USA.
C3 Princeton University
NR 25
TC 112
Z9 115
U1 0
U2 4
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 627
EP 630
DI 10.1038/349627a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000065
PM 2000136
DA 2026-03-10
ER

PT J
AU RUPPERSBERG, JP
   FRANK, R
   PONGS, O
   STOCKER, M
AF RUPPERSBERG, JP
   FRANK, R
   PONGS, O
   STOCKER, M
TI CLONED NEURONAL IK(A) CHANNELS REOPEN DURING RECOVERY FROM INACTIVATION
SO NATURE
LA English
DT Article
ID potassium channels; diversity
AB THE kinetic behaviour and functional role of potassium ion (K+) channels mediating a fast-inactivating K+ current (I(K)(A)) has been widely discussed 1. Activating in the subthreshold range of excitation, I(K)(A) channels are assumed to reduce the excitatory effect of depolarizing membrane currents in a time-dependent manner. Here we report that I(K)(A) channels not only open in response to a depolarization but open again after repolarization of the membrane. Although the current in response to the depolarization is rapidly inactivating, the current elicited by repolarization declines slowly and produces long-lasting after hyperpolarizations under current-clamp conditions. This implies an additional physiological role for I(K)(A) channels, particularly those that activate positive to the threshold of excitation. The underlying biophysical mechanism was studied by fast-application of peptides corresponding to the N-terminal end of the I(K)(A) channel proteins. It was found to be a voltage-dependent release of the inactivation gate.
C1 ZENTRUM MOLEK BIOL,W-6900 HEIDELBERG,GERMANY.
   RUHR UNIV BOCHUM,LEHRSTUHL BIOCHEM,W-4300 BOCHUM,GERMANY.
C3 Ruprecht Karls University Heidelberg; Ruhr University Bochum
RP RUPPERSBERG, JP (corresponding author), MAX PLANCK INST MED RES,ZELLPHYSIOL ABT,JAHNSTR 29,W-6900 HEIDELBERG 1,GERMANY.
NR 14
TC 137
Z9 140
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 657
EP 660
DI 10.1038/353657a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200069
PM 1922383
DA 2026-03-10
ER

PT J
AU REISZ, RR
   LAURIN, M
AF REISZ, RR
   LAURIN, M
TI OWENETTA AND THE ORIGIN OF TURTLES
SO NATURE
LA English
DT Article
ID oldest
AB THE origin and relationships of turtles have fascinated and puzzled generations of palaeontologists.  Among living amniotes only turtles, crocodiles and mammals have substantial fossil records, extending into the Triassic (200 Myr).  These vertebrates have attracted much attention and the broader aspects of crocodilian and mammalian evolutionary relationships are relatively well known.  Therefore, it is surprising that the origins and relationships of the Testudines have remained unresolved.  Numerous groups of extinct tetrapods 1-7 have been cited as possible turtle relatives, including the Captorhinidae 8-12.  New specimens of the small reptile Owenetta from the Upper Permian and Lower Triassic sediments of South Africa provide strong evidence that a group of primitive amniotes, the procolophonids, are the closest sister-group of turtles.
RP REISZ, RR (corresponding author), UNIV TORONTO,DEPT ZOOL,ERINDALE CAMPUS,MISSISSAUGA L5L 1C6,ONTARIO,CANADA.
NR 17
TC 110
Z9 125
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 324
EP 326
DI 10.1038/349324a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100050
DA 2026-03-10
ER

PT J
AU GEERTS, H
   DEBRABANDER, M
   NUYDENS, R
AF GEERTS, H
   DEBRABANDER, M
   NUYDENS, R
TI NANOVID MICROSCOPY
SO NATURE
LA English
DT Article
ID contrast; cells; gold
RP GEERTS, H (corresponding author), JANSSEN RES FDN,DEPT PHYSIOL LIFE SCI,BEERSE,BELGIUM.
NR 8
TC 29
Z9 48
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 765
EP 765
DI 10.1038/351765a0
PG 1
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100071
PM 1712078
DA 2026-03-10
ER

PT J
AU OZIMA, M
   ZASHU, S
   TOMURA, K
   MATSUHISA, Y
AF OZIMA, M
   ZASHU, S
   TOMURA, K
   MATSUHISA, Y
TI CONSTRAINTS FROM NOBLE-GAS CONTENTS ON THE ORIGIN OF CARBONADO DIAMONDS
SO NATURE
LA English
DT Article
ID rocks
AB CARBONADOS are porous aggregates of micrometre-size diamond crystals 1,2. Although they are not rare, they have not been found in kimberlites 3, and they contain inclusion minerals typical of the Earth's crust, rather than the upper-mantle assemblages commonly found in kimberlite diamonds. Carbonados also have lower C-13/C-12 ratios than kimberlite diamonds 1,2,4. Although these observations strongly suggest that carbonados were formed in the crust, crustal conditions are generally unlikely to provide pressures and temperatures in the diamond stability field (but see ref. 5 for a possible exception). Other suggestions for the origin of carbonado include the transformation of subducted carbon in the mantle 6, impact metamorphism of crustal rocks containing organic carbon 7, and (for very fine-grained carbonado) the irradiation of organic matter by decaying uranium and thorium in uranium-rich phases 8-10. Here we present further evidence for a crustal connection, in the form of noble-gas data for four carbonados from Brazil and Africa.
C1 RIKKYO UNIV, INST ATOM ENERGY, YOKOHAMA 24001, JAPAN.
   GEOL SURVEY JAPAN, TSUKUBA 305, JAPAN.
   UNIV TOKYO, DEPT GEOPHYS, TOKYO 113, JAPAN.
C3 Rikkyo University; University of Tokyo
NR 16
TC 53
Z9 55
U1 0
U2 4
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 472
EP 474
DI 10.1038/351472a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800052
DA 2026-03-10
ER

PT J
AU PELLETIER, J
   BRUENING, W
   LI, FP
   HABER, DA
   GLASER, T
   HOUSMAN, DE
AF PELLETIER, J
   BRUENING, W
   LI, FP
   HABER, DA
   GLASER, T
   HOUSMAN, DE
TI WT1 MUTATIONS CONTRIBUTE TO ABNORMAL GENITAL SYSTEM-DEVELOPMENT AND HEREDITARY WILMS-TUMOR
SO NATURE
LA English
DT Article
ID sex-determining region; gene; dna; chromosome-11; deletion
AB WILMS' tumour (WT), aniridia, genitourinary abnormalities and mental retardation form a symptom group (WAGR syndrome) associated with hemizygous deletions of DNA in chromosome band 11p13 (refs 1, 2).  However, it has not been clear whether hemizygosity at a single locus contributes to more than one phenotype.  The tumour suppressor gene for Wilms' tumour, WT1, has been characterized 3,4:  it is expressed at high levels in the glomeruli of the kidney 5, as well as the gonadal ridge of the developing gonad 5, the Sertoli cells of the testis 6 and the epithelial and granulosa cells of the ovary 6, suggesting a developmental role in the genital system in addition to the kidney.  We now report constitutional mutations within the WT1 genes of two individuals with a combination of WT and genital abnormalities as evidence of a role for a recessive oncogene in mammalian development.
C1 MCGILL UNIV,CTR CANC,MONTREAL H3G 1Y6,QUEBEC,CANADA.
   NCI,DIV CANC ETIOL,CLIN EPIDEMIOL BRANCH,BETHESDA,MD 20892.
   HARVARD UNIV,SCH MED,DANA FARBER CANC INST,DIV BIOSTAT & EPIDEMIOL,BOSTON,MA 02115.
   MASSACHUSETTS GEN HOSP,BOSTON,MA 02114.
   HARVARD UNIV,BRIGHAM & WOMENS HOSP,HOWARD HUGHES MED INST,BOSTON,MA 02115.
C3 McGill University; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Dana-Farber Cancer Institute; Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Howard Hughes Medical Institute
RP PELLETIER, J (corresponding author), MIT,CTR CANC RES,CAMBRIDGE,MA 02139, USA.
NR 16
TC 424
Z9 443
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 431
EP 434
DI 10.1038/353431a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600057
PM 1654525
DA 2026-03-10
ER

PT J
AU YAMAGATA, Y
   WATANABE, H
   SAITOH, M
   NAMBA, T
AF YAMAGATA, Y
   WATANABE, H
   SAITOH, M
   NAMBA, T
TI VOLCANIC PRODUCTION OF POLYPHOSPHATES AND ITS RELEVANCE TO PREBIOTIC EVOLUTION
SO NATURE
LA English
DT Article
ID aqueous-solution; phosphorylation; phosphorus; adenosine; agents
AB PHOSPHATES would probably have been essential compounds for prebiotic evolution on the primitive Earth. In this context, there have been several studies of condensation of water-soluble phosphates to polyphosphates and phosphorylation and condensation or polymerization of biomolecules with polyphosphates 1-20. But most of the phosphorus on the early Earth would have been in the form of water-insoluble apatite, and the origin of the water-soluble polyphosphates required for prebiotic evolution has therefore been a mystery 21-24. Here we show, both from experiments that simulate magmatic conditions and from analysis of volatile condensates in volcanic gas, that volcanic activity can produce water-soluble polyphosphates through partial hydrolysis of P4O10. This mechanism seems to be the only viable route identified so far for the production of these species on the primitive Earth.
RP YAMAGATA, Y (corresponding author), KANAZAWA UNIV, FAC SCI, DEPT PHYS, 1-1 MARUNOUCHI, KANAZAWA, ISHIKAWA 920, JAPAN.
NR 34
TC 279
Z9 314
U1 0
U2 63
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 516
EP 519
DI 10.1038/352516a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600058
PM 11536483
DA 2026-03-10
ER

PT J
AU SATHYENDRANATH, S
   PLATT, T
   HORNE, EPW
   HARRISON, WG
   ULLOA, O
   OUTERBRIDGE, R
   HOEPFFNER, N
AF SATHYENDRANATH, S
   PLATT, T
   HORNE, EPW
   HARRISON, WG
   ULLOA, O
   OUTERBRIDGE, R
   HOEPFFNER, N
TI ESTIMATION OF NEW PRODUCTION IN THE OCEAN BY COMPOUND REMOTE-SENSING
SO NATURE
LA English
DT Article
ID nitrate; temperature; chlorophyll; fluxes; color; light
AB Oceanic new production can be estimated from remotely sensed data on ocean colour and temperature. This approach, which depends on parameterizations developed from ship observations, as well as on satellite data, yields more representative estimates of the large-scale average new production than those calculated from ship data alone.
C1 DALHOUSIE UNIV, DEPT OCEANOG, HALIFAX B3H 4J1, NS, CANADA.
C3 Dalhousie University
RP SATHYENDRANATH, S (corresponding author), FISHERIES & OCEANS CANADA, BEDFORD INST OCEANOG, DIV BIOL OCEANOG, BOX 1006, DARTMOUTH B2Y 4A2, NS, CANADA.
NR 35
TC 151
Z9 161
U1 0
U2 18
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 129
EP 133
DI 10.1038/353129a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100042
DA 2026-03-10
ER

PT J
AU ANDERSSON, S
   BERMAN, DM
   JENKINS, EP
   RUSSELL, DW
AF ANDERSSON, S
   BERMAN, DM
   JENKINS, EP
   RUSSELL, DW
TI DELETION OF STEROID 5-ALPHA-REDUCTASE 2-GENE IN MALE PSEUDOHERMAPHRODITISM
SO NATURE
LA English
DT Article
ID sexual-differentiation; 5alpha-reductase; expression; enzyme; genome; rat; fibroblasts; inhibitor; cloning; virus
AB THE conversion of testosterone into dihydrotestosterone by steroid 5-alpha-reductase is a key reaction in androgen action, and is essential both for the formation of the male phenotype during embryogenesis and for androgen-mediated growth of tissues such as the prostate Single gene defects that impair this conversion lead to pseudohermaphroditism in which 46 X, Y males have male internal urogenital tracts, but female external genitalia 3. We have described the isolation of a human 5-alpha-reductase complementary DNA from prostate . Subsequent cloning and genetic studies showed that this gene (designated 5-alpha-reductase 1) was normal in patients with 5-alpha-reductase deficiency 26. We report here the isolation of a second 5-alpha-reductase cDNA by expression cloning and the polymerase chain reaction. The biochemical and pharmacological properties of this cDNA-encoded enzyme (designated 5-alpha-reductase 2) are consistent with it being the major isozyme in genital tissue. A deletion in this gene is present in two related individuals with male pseudohermaphroditism caused by 5-alpha-reductase deficiency. These results verify the existence of at least two 5-alpha-reductases in man and provide insight into a fundamental hormone-mediated event in male sexual differentiation.
C1 UNIV TEXAS,SW MED CTR,DEPT MOLEC GENET,DALLAS,TX 75235.
C3 University of Texas System; University of Texas Dallas; University of Texas Southwestern Medical Center
FU National Heart Lung and Blood Institute [P01HL020948] Funding Source: NIH RePORTER; NHLBI NIH HHS [P01 HL020948] Funding Source: Medline
NR 27
TC 631
Z9 683
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 159
EP 161
DI 10.1038/354159a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000063
PM 1944596
DA 2026-03-10
ER

PT J
AU LIMAN, ER
   HESS, P
   WEAVER, F
   KOREN, G
AF LIMAN, ER
   HESS, P
   WEAVER, F
   KOREN, G
TI VOLTAGE-SENSING RESIDUES IN THE S4 REGION OF A MAMMALIAN K+ CHANNEL
SO NATURE
LA English
DT Article
ID potassium channel; sodium-channel; drosophila; oocytes
AB THE ability of ion-channel proteins to respond to a change of the transmembrane voltage is one of the basic mechanisms underlying electrical excitability of nerve and muscle membranes. The voltage sensor has been postulated to be the fourth putative transmembrane segment 1 (S4) of voltage-activated Na+, Ca2+ and K+ channels 1-5. Mutations of positively charged residues within S4 alter gating of Na 4 and Shaker-type K+ channels 5, but quantitative correlations between the charge or a residue in S4 and the gating valence of the channel have not yet been established. Here, with improved resolution of the voltage dependence of steady-state activation, we present estimates of the equivalent gating valence with sufficient precision to allow quantitative examination of the contribution of individual charged residues to the gating valence of a mammalian non-inactivating K+ channel. We conclude that at least part of the gating charge associated with channel activation is indeed contributed by charged residues within the S4 segment.
C1 HARVARD UNIV,SCH MED,DEPT CELLULAR & MOLEC PHYSIOL,25 SHATTUCK ST,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,PROGRAM NEUROSCI,BOSTON,MA 02115.
   BRIGHAM & WOMENS HOSP,DEPT CARDIOL,BOSTON,MA 02115.
C3 Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital
NR 24
TC 253
Z9 279
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 752
EP 756
DI 10.1038/353752a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600068
PM 1944534
DA 2026-03-10
ER

PT J
AU SOKOL, S
   MELTON, DA
AF SOKOL, S
   MELTON, DA
TI PREEXISTENT PATTERN IN XENOPUS ANIMAL POLE CELLS REVEALED BY INDUCTION WITH ACTIVIN
SO NATURE
LA English
DT Article
ID neural induction; laevis; mesoderm; embryos; axis; differentiation; gastrulation; homolog; signals; marker
AB ACTIVIN, a peptide growth factor related to tumour growth factor-beta, has been implicated in early inductive interactions in vertebrates 1-4 and can induce Xenopus blastula ectodermal explants to develop a rudimentary axial pattern with anteroposterior and dorsoventral polarity 4, 5.  Here we demonstrate that prospective dorsal and ventral regions of the ectoderm respond differently to the same concentration of activin.  Thus, activin does not seem to endow ectodermal cells with polarity but rather reveals a pre-existent pattern.  Our results suggest that patterning of mesoderm is determined not only by a localized inducer, but also by the differential competence of cells in the responding tissue.
RP SOKOL, S (corresponding author), HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,7 DIVIN AVE,CAMBRIDGE,MA 02138, USA.
NR 20
TC 194
Z9 200
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 409
EP 411
DI 10.1038/351409a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600059
PM 2034291
DA 2026-03-10
ER

PT J
AU MADDEN, DR
   GORGA, JC
   STROMINGER, JL
   WILEY, DC
AF MADDEN, DR
   GORGA, JC
   STROMINGER, JL
   WILEY, DC
TI THE STRUCTURE OF HLA-B27 REVEALS NONAMER SELF-PEPTIDES BOUND IN AN EXTENDED CONFORMATION
SO NATURE
LA English
DT Article
ID class-i molecules; direct binding; histocompatibility antigen; viral peptides; intact-cells; t-cells; invitro; recognition; protein; chains
AB X-ray crystallography reveals electron density in the antigen-binding site of HLA-B27 that is an interpretable image of nonameric peptides in a largely extended conformation.  Clear density exists for the main chain and several side chains and is consistent with the sequence of 11 nonameric self-peptides eluted from HLA-B27 (see accompanying article 1).  Pockets in the antigen-binding cleft bind four side chains and the amino and carboxyl termini of the peptide.
C1 HARVARD UNIV,HOWARD HUGHES MED INST,CAMBRIDGE,MA 02138.
   HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,CAMBRIDGE,MA 02138.
C3 Howard Hughes Medical Institute; Harvard University; Harvard University
RP MADDEN, DR (corresponding author), HARVARD UNIV,COMM HIGHER DEGREES BIOPHYS,7 DIVIN AVE,CAMBRIDGE,MA 02138, USA.
NR 41
TC 703
Z9 750
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 321
EP 325
DI 10.1038/353321a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400048
PM 1922337
DA 2026-03-10
ER

PT J
AU MCHEYZERWILLIAMS, MG
   NOSSAL, GJV
   LALOR, PA
AF MCHEYZERWILLIAMS, MG
   NOSSAL, GJV
   LALOR, PA
TI MOLECULAR CHARACTERIZATION OF SINGLE MEMORY B-CELLS
SO NATURE
LA English
DT Article
ID somatic mutation; immune-response; antibody repertoire; mouse; hypermutation; generation; antigen; mice; dna; np
AB PRIMARY antigenic exposure results in an initial antibody response and the T cell-dependent induction of B-cell memory 1,2. Memory B-cell differentiation is characterized by somatic hypermutation in antibody variable region genes (V) and selection of B cells expressing high-affinity variants of this antigen receptor 3-5. Despite our current understanding of B-cell memory 6-8, the origin of memory B cells and the regulation of their differentiation remain elusive. This is largely due to the difficulties in observing and purifying this minor component of the immunized spleen. Further, molecular characterization of memory B cells requires hybridoma formation which restricts analyses to only those clones capable of fusion and does not allow isolation of cells in a normal physiological state. We have therefore developed a unique system which allows isolation and unambiguous enumeration of IgG1+ memory B cells, based on six-parameter flow cytometry, secretion of antibody in clonal cultures and analysis of clonally expressed V genes using the polymerase chain reaction 9. Here we report that single IgG1+ antigen-binding B cells from an early secondary immune response proliferate in lipopolysaccharide-driven microcultures and produce antigen-specific IgG1 antibodies. Individual B-cell clones in these cultures express somatically mutated heavy chain V genes, confirming their designation as memory B cells. Although isolated memory B cells undergo extensive proliferation in vitro, V gene sequence analysis of their individual progeny shows that further hypermutation does not occur.
RP MCHEYZERWILLIAMS, MG (corresponding author), ROYAL MELBOURNE HOSP, WALTER & ELIZA HALL INST MED RES, PARKVILLE, VIC 3050, AUSTRALIA.
NR 30
TC 137
Z9 162
U1 0
U2 5
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 502
EP 505
DI 10.1038/350502a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300052
PM 2014051
DA 2026-03-10
ER

PT J
AU MOPPER, K
   ZHOU, XL
   KIEBER, RJ
   KIEBER, DJ
   SIKORSKI, RJ
   JONES, RD
AF MOPPER, K
   ZHOU, XL
   KIEBER, RJ
   KIEBER, DJ
   SIKORSKI, RJ
   JONES, RD
TI PHOTOCHEMICAL DEGRADATION OF DISSOLVED ORGANIC-CARBON AND ITS IMPACT ON THE OCEANIC CARBON-CYCLE
SO NATURE
LA English
DT Article
ID ultraviolet-radiation; natural-waters; pacific-ocean; sea-water; seawater; matter; fluorescence; radiocarbon; absorbance; photolysis
AB THE processes that regulate the cycling of oceanic dissolved organic carbon (DOC), one of the largest carbon reservoirs on the Earth's surface 1, are largely unknown. DOC residues in the deep sea, below 500 m, seem to be composed mainly of biologically refractory compounds 2-10 such as humic substances 11.  The average apparent C-14 age of this refractory DOC is > 6,000 yr in the deep Pacific 2, suggesting that its rate of turnover is slow, but the pathways and rates responsible for this apparent slow turnover are unknown. Several studies have shown that aquatic humic substances are photochemically degraded by sunlight into biologically labile and/or volatile organic compounds 12-14 and carbon monoxide 15,16. Here we present new data which suggest that this photochemical degradation pathway is the rate-limiting step for the removal of a large fraction of oceanic DOC. This rate will increase with increasing flux of solar ultraviolet-B radiation. We estimate the oceanic residence time of biologically refractory, photochemically reactive DOC to be 500-2,100 yr, which is less than its average apparent C-14 age. The injection of 'old carbon' from sediments into the deep sea may explain this discrepancy.
C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149.
   FLORIDA INT UNIV,DRINKING WATER RES CTR,MIAMI,FL 33199.
   FLORIDA INT UNIV,DEPT BIOL SCI,MIAMI,FL 33199.
C3 University of Miami; State University System of Florida; Florida International University; State University System of Florida; Florida International University
NR 53
TC 537
Z9 628
U1 4
U2 200
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 60
EP 62
DI 10.1038/353060a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500056
DA 2026-03-10
ER

PT J
AU MANGO, FD
AF MANGO, FD
TI THE STABILITY OF HYDROCARBONS UNDER THE TIME TEMPERATURE CONDITIONS OF PETROLEUM GENESIS
SO NATURE
LA English
DT Article
ID oil; asphaltenes; pyrolysis; origin; gas
AB THE contention that hydrocarbons are unstable under the time-temperature conditions of petroleum generation (catagenesis) enjoys broad acceptance 1-6.   At temperatures in the region of 100-150-degrees-C, hydrocarbons are believed to decompose progressively over geological time to lighter hydrocarbons, ultimately methane and pyrobitumen 7,8.  There are geological contradictions to this view 9, however, and the recent finding 10 that the cycloalkane ring should remain stable for billions of years under catagenic conditions demands a review of its underlying assumptions.  For example, are ordinary hydrocarbons unstable under catagenic conditions?   Are the light hydrocarbons, including methane, produced through the thermal decomposition of higher-molecular-weight hydrocarbons?  Here I address these questions from two independent perspectives.  First, the relative stabilities of hydrocarbons and their kerogenous precursors are studied experimentally.  Second, the compositions of natural petroleum deposits are analysed for evidence of thermal decomposition.  The results suggest that the hydrocarbons in petroleum should be at least three orders of magnitude more stable than their kerogenous precursors under catagenic conditions, and that natural deposits of petroleum and gas do not contain cycloalkane and isoalkane contents indicative of progressive thermal decomposition to gas.  Thus the assumption that hydrocarbons are unstable under catagenic conditions and progressively decompose to methane and pyrobitumen seems to be incorrect.
RP MANGO, FD (corresponding author), SHELL DEV CO,BELLAIRE RES CTR,POB 481,HOUSTON,TX 77001, USA.
NR 24
TC 81
Z9 111
U1 0
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 146
EP 148
DI 10.1038/352146a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700052
DA 2026-03-10
ER

PT J
AU PARSELL, DA
   SANCHEZ, Y
   STITZEL, JD
   LINDQUIST, S
AF PARSELL, DA
   SANCHEZ, Y
   STITZEL, JD
   LINDQUIST, S
TI HSP104 IS A HIGHLY CONSERVED PROTEIN WITH 2 ESSENTIAL NUCLEOTIDE-BINDING SITES
SO NATURE
LA English
DT Article
ID atp-dependent protease; heat-shock protein; escherichia-coli; clp protease; component; subunits; ti; purification; fibroblasts; sequences
AB MOST eukaryotic cells produce proteins with relative molecular masses in the range of 100,000 to 110,000 after exposure to high temperatures 1. These proteins have been studied only in yeast and mammalian cells. In Saccharomyces cerevisiae, heat-shock protein hsp104 is vital for tolerance to heat, ethanol and other stresses (ref. 2, and Y.S. et al., manuscript submitted). The mammalian hsp110 protein is nucleolar and redistributes with growth state, nutritional conditions and heat shock 3-5. The relationships between hsp110, hsp104 and the high molecular mass heat-shock proteins of other organisms were unknown. We report here that hsp104 is a member of the highly conserved ClpA/ClpB protein family first identified in Escherichia coli 6 and that additional heat-inducible members of this family are present in Schizosaccharomyces pombe and in mammals. Mutagenesis of two putative nucleotide-binding sites in hsp104 indicates that both are essential for function in thermotolerance.
C1 UNIV CHICAGO, HOWARD HUGHES MED INST, 5841 S MARYLAND AVE, CHICAGO, IL 60637 USA.
   UNIV CHICAGO, DEPT MOLEC GENET & CELL BIOL, CHICAGO, IL 60637 USA.
C3 University of Chicago; Howard Hughes Medical Institute; University of Chicago
NR 30
TC 232
Z9 258
U1 0
U2 1
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 270
EP 273
DI 10.1038/353270a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400064
PM 1896074
DA 2026-03-10
ER

PT J
AU ATTEIA, JL
   BARAT, C
   JOURDAIN, E
   NIEL, M
   VEDRENNE, G
   BLINOV, N
   CHERNENKO, A
   DOLIDZE, V
   KOZLENKOV, A
   KUZNETSOV, A
   MITROFANOV, IG
   POZANENKO, A
   SUNYAEV, R
   TEREKHOV, O
AF ATTEIA, JL
   BARAT, C
   JOURDAIN, E
   NIEL, M
   VEDRENNE, G
   BLINOV, N
   CHERNENKO, A
   DOLIDZE, V
   KOZLENKOV, A
   KUZNETSOV, A
   MITROFANOV, IG
   POZANENKO, A
   SUNYAEV, R
   TEREKHOV, O
TI STATISTICAL EVIDENCE FOR A GALACTIC ORIGIN OF GAMMA-RAY BURSTS
SO NATURE
LA English
DT Article
ID accreting neutron-stars; constraints
AB ASTRONOMICAL bursts of gamma-rays (GRBs) were first discovered 20 years ago, and approximately 100 are recorded every year by satellite-borne instruments.  Bursts last for at most a few seconds, recur only on a timescale of years, if at all, and come from objects which have remained undetected at all other wavelengths. It has been impossible to establish a distance scale for GRBs, and no association with known astronomical objects has been demonstrated.  Here we analyse the spatial distribution of GRBs 1,2 with a view to understanding their true radial distribution.  Our data consist of three samples, totalling 244 GRBs, obtained by three French-Soviet experiments flown on the Venera 13 and 14 and the Phobos missions.  We conclude that the underlying GRB distribution is not uniformly distributed in space, but falls off with distance.  Our analysis of the weak sources in particular suggests that GRBs are associated with the galactic plane.
C1 MOSCOW SPACE RES INST,MOSCOW 117810,USSR.
C3 Russian Academy of Sciences; Space Research Institute of the Russian Academy of Sciences
RP ATTEIA, JL (corresponding author), CTR ETUD SPATIALE RAYONNEMENTS,9 AVE COLONEL ROCHE,BP 4346,F-31029 TOULOUSE,FRANCE.
NR 16
TC 41
Z9 41
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 296
EP 298
DI 10.1038/351296a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600051
DA 2026-03-10
ER

PT J
AU JUDAS, D
   GERMAIN, Y
   BIVER, C
   GIRAULT, S
AF JUDAS, D
   GERMAIN, Y
   BIVER, C
   GIRAULT, S
TI POLYMER DESIGN FOR HIGH-PERFORMANCE MATERIALS - LIQUID-CRYSTAL POLYMERS
SO NATURE
LA English
DT Article
ID x-ray; chain; copolyesters; model
C1 ATOCHEM CAL,F-92300 LEVALLOIS PERRET,FRANCE.
RP JUDAS, D (corresponding author), ATOCHEM,CERDATO BP 19,F-27470 SERQUIGNY,FRANCE.
NR 26
TC 1
Z9 1
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 28
EP 29
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100010
DA 2026-03-10
ER

PT J
AU WILLIAMS, DE
   NEWMAN, RC
   SONG, Q
   KELLY, RG
AF WILLIAMS, DE
   NEWMAN, RC
   SONG, Q
   KELLY, RG
TI PASSIVITY BREAKDOWN AND PITTING CORROSION OF BINARY-ALLOYS
SO NATURE
LA English
DT Article
ID stainless-steels; stochastic-models; percolation model; dissolution; metals; passivation; initiation; growth; films; acid
AB Pitting corrosion-the localized dissolution of a passivated (oxide-covered) metal in the presence of a solution of certain anionic species-is a major cause of failure of metal structures. The breakdown of extremely thin (approximately 1 nm thick), highly stable passivating layers typically occurs in a sporadic, localized and stochastic fashion 1,2, rather than as a catastrophic, global process. Using a model of a random binary iron-chromium alloy, we have shown previously 3-6 that experimental observations of passivity of stainless steels can be explained by assuming that it is controlled by the selective dissolution of iron 7. Thus if the chromium content is above a certain threshold (the percolation limit 8), clusters of iron are finite and dissolution will proceed for a while and then stop. Oxidation of surface chromium atoms to form Cr-O-Cr linkages then creates a passive state in which the entire surface is covered with such a layer 3,5. Here we show that, by adding to this model the further assumption that there is a small but finite dissolution rate for surface chromium atoms, one obtains a mechanism for the triggering of pitting corrosion of stainless steels that is consistent with experimental studies.
C1 UKAEA, HARWELL LAB, AEA IND TECHNOL, HARWELL OX11 0RA, BERKS, ENGLAND.
   UNIV MANCHESTER, INST SCI & TECHNOL, CTR CORROS & PROTECT, MANCHESTER M60 1QD, LANCS, ENGLAND.
   UNIV VIRGINIA, SCH ENGN & APPL SCI, CHARLOTTESVILLE, VA 22903 USA.
C3 UK Atomic Energy Authority; University of Manchester; University of Virginia
NR 31
TC 168
Z9 198
U1 2
U2 114
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 216
EP 219
DI 10.1038/350216a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900051
DA 2026-03-10
ER

PT J
AU CHEN, KY
AF CHEN, KY
TI GAMMA-RAY EMISSION FROM MILLISECOND PULSARS IN GLOBULAR-CLUSTERS
SO NATURE
LA English
DT Article
ID radiation; evolution; binary; crab; vela
AB RECENT observations indicate that a typical globular cluster may contain hundreds of millisecond pulsars 1,2. Because millisecond pulsars have some similarities to the Vela pulsar, which is known to be a source of gamma-rays, they could also be gamma emitters of modest power. Here I estimate the gamma-ray luminosity of globular clusters, assuming that they indeed harbour large numbers of millisecond pulsars. An upper limit obtained by the Cos-B satellite on the gamma-ray emission from 47 Tucanae, which contains at least 10 millisecond pulsars 1, is too large to constrain the model presented here, but the estimated luminosities are high enough to be detectable by the recently launched Gamma Ray Observatory. In the near future, gamma-ray observations will thus be able to test this model, and the theory of gamma-ray emission by millisecond pulsars.
RP CHEN, KY (corresponding author), UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106, USA.
NR 17
TC 21
Z9 22
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 695
EP 697
DI 10.1038/352695a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400049
DA 2026-03-10
ER

PT J
AU ROBERTS, DH
   LEHAR, J
   HEWITT, JN
   BURKE, BF
AF ROBERTS, DH
   LEHAR, J
   HEWITT, JN
   BURKE, BF
TI THE HUBBLE CONSTANT FROM VLA MEASUREMENT OF THE TIME-DELAY IN THE DOUBLE QUASAR 0957+561
SO NATURE
LA English
DT Article
ID gravitational lens; q0957+561; galaxy; images; a,b
AB IN the double quasar 0957 + 0561, the first detected example of a gravitational lens 1, a quasar at redshift z = 1.41 appears as two images separated by approximately 6 arcsec and accompanied by an extended radio source 2-4. The Hubble constant, H0, can be estimated from the angular separation and the time delay between the appearance of the same brightness variations in the two images-a method that avoids all the usual uncertainties that attend the estimation of distance by the use of standard candles. From 11 years of Very Large Array (VLA) observations we have found the time delay to be l.40 +/- 0.10 yr, a significantly larger and more robust value than has been obtained from optical measurements 5,6. Using a standard lens model 7  and taking the observed velocity dispersion of luminous matter in the lensing galaxy 8 to measure the true gravitational potential, we find H0 = 46 +/- 14 (42 +/- 14) km s-1 Mpc-1 for cosmic density parameter OMEGA-0 = 0 (1), in approximate agreement with Rhee's recent estimate 8. But if, as is likely, there is dark matter in the lensing galaxy, H0 could be as high as 69 +/- 21 (63 +/- 21) km s-1 Mpc-1. The agreement of several completely independent estimates of H0 gives some confidence that the scale of the Universe is indeed known to about a factor of two.
C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139.
C3 Massachusetts Institute of Technology (MIT)
RP ROBERTS, DH (corresponding author), BRANDEIS UNIV,DEPT PHYS,WALTHAM,MA 02254, USA.
NR 27
TC 41
Z9 41
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 43
EP 45
DI 10.1038/352043a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800062
DA 2026-03-10
ER

PT J
AU SHANKS, T
   GEORGANTOPOULOS, I
   STEWART, GC
   POUNDS, KA
   BOYLE, BJ
   GRIFFITHS, RE
AF SHANKS, T
   GEORGANTOPOULOS, I
   STEWART, GC
   POUNDS, KA
   BOYLE, BJ
   GRIFFITHS, RE
TI THE ORIGIN OF THE COSMIC X-RAY-BACKGROUND
SO NATURE
LA English
DT Article
ID quasars; reflection; confusion; galaxy; spectrum; counts; nuclei
AB A high-resolution image from the Rosat X-ray satellite reveals many faint discrete sources in the 0.1-2-keV energy range.  Optical spectroscopy of these sources performed at the Anglo-Australian Telescope shows that many of them are quasars, and the inferred density of quasars on the sky contributes at least 30% of the cosmic X-ray background at 1 keV.
C1 UNIV LEICESTER,DEPT PHYS & ASTRON,LEICESTER LE1 7RH,ENGLAND.
   UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND.
   SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218.
C3 University of Leicester; University of Cambridge; Space Telescope Science Institute
RP SHANKS, T (corresponding author), UNIV DURHAM,DEPT PHYS,S RD,DURHAM DH1 3LE,ENGLAND.
NR 34
TC 180
Z9 185
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 315
EP 320
DI 10.1038/353315a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400047
DA 2026-03-10
ER

PT J
AU VU, TKH
   WHEATON, VI
   HUNG, DT
   CHARO, I
   COUGHLIN, SR
AF VU, TKH
   WHEATON, VI
   HUNG, DT
   CHARO, I
   COUGHLIN, SR
TI DOMAINS SPECIFYING THROMBIN-RECEPTOR INTERACTION
SO NATURE
LA English
DT Article
ID human alpha-thrombin; recombinant hirudin; site
AB PLATELET activation by the coagulation protease thrombin is central to arterial thrombosis, a major cause of morbidity and mortality. We recently isolated a complementary DNA encoding the platelet thrombin receptor. The extracellular amino-terminal extension of this seven transmembrane domain receptor contains the putative thrombin cleavage site LDPR/S which is critical for receptor activation. By replacing this cleavage site with the cleavage site for enterokinase, we have created a functional enterokinase receptor. This result demonstrates that all information necessary for receptor activation is provided by receptor proteolysis. Nanomolar enterokinase concentrations are required to activate this new receptor, in contrast to the picomolar thrombin concentrations that activate wild-type thrombin receptor. We identified a receptor domain critical for thrombin's remarkable potency at its receptor. This domain resembles the carboxyl tail of the leech anticoagulant hirudin and functions by binding to thrombin's anion-binding exosite. Our studies thus define a model for thrombin-receptor interaction. The utility of this model was demonstrated by the design of novel thrombin inhibitors based on receptor peptides.
C1 UNIV CALIF SAN FRANCISCO,CARDIOVASC RES INST,SAN FRANCISCO,CA 94143.
   UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94143.
   COR THERAPEUT INC,S SAN FRANCISCO,CA 94080.
C3 University of California System; University of California San Francisco; University of California System; University of California San Francisco; Takeda Pharmaceutical Company Ltd; Millennium Pharmaceuticals
NR 12
TC 548
Z9 611
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 674
EP 677
DI 10.1038/353674a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200076
PM 1717851
DA 2026-03-10
ER

PT J
AU NAKADA, Y
   DEGUCHI, S
   HASHIMOTO, O
   IZUMIURA, H
   ONAKA, T
   SEKIGUCHI, K
   YAMAMURA, I
AF NAKADA, Y
   DEGUCHI, S
   HASHIMOTO, O
   IZUMIURA, H
   ONAKA, T
   SEKIGUCHI, K
   YAMAMURA, I
TI IS THE BULGE OF OUR GALAXY TRIAXIAL
SO NATURE
LA English
DT Article
ID galactic bulge; region
AB As in the case of other spiral galaxies, such as M31 (refs 1, 2), the rotation curve of gas in our Galaxy indicates that its nuclear bulge is triaxial 3.  Despite several studies 4,5 of the distribution of specific objects in the galactic bulge, no observational evidence of asymmetry has emerged. Recently, however, Blitz and Spergel 6 have reanalysed balloon-infrared observations at 2.4-mu-m, where obscuration is relatively low, to suggest that the galactic bulge is bar-like, and tilted with respect to the plane of the Galaxy. Here we report that the distribution of IRAS (the Infrared Astronomy Satellite) bulge stars shows an asymmetry with respect to the Galactic Centre, providing clear evidence for triaxiality.
C1 NOBEYAMA RADIO OBSERV,MINAMISA,NAGANO 38413,JAPAN.
   SEIKEI UNIV,DEPT APPL PHYS,MUSASHINO,TOKYO 180,JAPAN.
   TOKYO GAKUGEI UNIV,DEPT ASTRON & EARTH SCI,KOGANEI,TOKYO 184,JAPAN.
   S AFRICAN ASTRON OBSERV,CAPE TOWN 7935,SOUTH AFRICA.
C3 National Institutes of Natural Sciences (NINS) - Japan; National Astronomical Observatory of Japan (NAOJ); Seikei University; Tokyo Gakugei University; National Research Foundation - South Africa; South African Astronomical Observatory
RP NAKADA, Y (corresponding author), UNIV TOKYO,DEPT ASTRON,BUNKYO KU,TOKYO 113,JAPAN.
NR 18
TC 104
Z9 105
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 140
EP 141
DI 10.1038/353140a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100044
DA 2026-03-10
ER

PT J
AU SOKAL, RR
   ODEN, NL
   WILSON, C
AF SOKAL, RR
   ODEN, NL
   WILSON, C
TI GENETIC-EVIDENCE FOR THE SPREAD OF AGRICULTURE IN EUROPE BY DEMIC DIFFUSION
SO NATURE
LA English
DT Article
ID frequency; populations; transition; distances; patterns
AB EUROPEAN agriculture originated in the Near East about 9,000 years ago 1-3. The Neolithic reached almost all areas suitable for agriculture by 5,000 yr BP (before present) 2,4. The routes and times of the spread of agriculture through Europe are relatively well established 2,3,5, but not its manner of spreading 6-8. This could have been by cultural diffusion with few genetic consequences. By contrast, Ammerman and Cavalli-Sforza 2 proposed that the spread of farming increased local population densities, causing demic expansion into new territory and diffusive gene flow between the neolithic farmers and mesolithic groups. We have now tested observed genetic patterns against expectations derived from the demic expansion hypothesis. We found significant partial correlations of genetic distances with a distance matrix especially designed to represent the spread of agriculture on that continent, when geographic distances are held constant. These findings support the hypothesis of Ammerman and Cavalli-Sforza and invite further investigation into Renfrew's hypothesis on the origin of the Indo-European languages.
C1 SUNY STONY BROOK, HLTH SCI CTR, DEPT PREVENT MED, DIV MICROBIOL & PUBL HLTH, STONY BROOK, NY 11794 USA.
C3 State University of New York (SUNY) System; Stony Brook University
RP SOKAL, RR (corresponding author), SUNY STONY BROOK, DEPT ECOL & EVOLUT, STONY BROOK, NY 11794 USA.
NR 28
TC 237
Z9 264
U1 0
U2 25
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 143
EP 145
DI 10.1038/351143a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500049
PM 2030731
DA 2026-03-10
ER

PT J
AU CO, MS
   QUEEN, C
AF CO, MS
   QUEEN, C
TI HUMANIZED ANTIBODIES FOR THERAPY
SO NATURE
LA English
DT Article
ID interleukin-2 receptor; mouse
RP CO, MS (corresponding author), PROT DESIGN LABS INC, 2375 GARCIA AVE, MT VIEW, CA 94043 USA.
NR 13
TC 78
Z9 143
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 501
EP 502
DI 10.1038/351501a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800062
PM 2046753
DA 2026-03-10
ER

PT J
AU HAGAN, P
   BLUMENTHAL, UJ
   DUNN, D
   SIMPSON, AJG
   WILKINS, HA
AF HAGAN, P
   BLUMENTHAL, UJ
   DUNN, D
   SIMPSON, AJG
   WILKINS, HA
TI HUMAN IGE, IGG4 AND RESISTANCE TO REINFECTION WITH SCHISTOSOMA-HAEMATOBIUM
SO NATURE
LA English
DT Article
ID protective immunity; antibody; mansoni; cells; responses; macrophages; invitro; gamma
AB A WELL recognized feature of the immune response to parasitic helminth infections, including schistosomiasis, is the production of large amounts of specific and nonspecific IgE 1,2. Immunological pathways involving IgE can lead to damage to the developing schistosomulum 3-9 and it has been suggested that responses involving IgE could have evolved as protection against helminth infections 10,11. There has been no epidemiological evidence to support this idea and the only significant IgE responses known in man are those involved in the pathogenesis of allergic disease 12. Here we measure serological response during reinfection with S. haematobium and demonstrate that IgE antibodies in man can be beneficial. Our results support the hypothesis that the slow build-up of IgE to high levels and the early production of IgG4 antibodies, which may block IgE pathways 13,14, are responsible for delaying the development of protective immunity to S. haematobium.
C1 UNIV LIVERPOOL, LIVERPOOL SCH TROP MED, LIVERPOOL L3 5QA, ENGLAND.
   UNIV LONDON LONDON SCH HYG & TROP MED, LONDON WC1E 7HT, ENGLAND.
   MRC LABS, FAJARA, SENEGAMBIA.
C3 University of Liverpool; Liverpool School of Tropical Medicine; University of London; London School of Hygiene & Tropical Medicine
RP HAGAN, P (corresponding author), NATL INST MED RES, DIV PARASITOL, LONDON NW7 1AA, ENGLAND.
NR 30
TC 597
Z9 626
U1 0
U2 22
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 243
EP 245
DI 10.1038/349243a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900057
PM 1898985
DA 2026-03-10
ER

PT J
AU GOLDSTEIN, DJ
   FINBOW, ME
   ANDRESSON, T
   MCLEAN, P
   SMITH, K
   BUBB, V
   SCHLEGEL, R
AF GOLDSTEIN, DJ
   FINBOW, ME
   ANDRESSON, T
   MCLEAN, P
   SMITH, K
   BUBB, V
   SCHLEGEL, R
TI BOVINE PAPILLOMAVIRUS-E5 ONCOPROTEIN BINDS TO THE 16K COMPONENT OF VACUOLAR H+-ATPASES
SO NATURE
LA English
DT Article
ID open reading frame; transforming activity; gap-junctions; e5; protein; gene; localization; polypeptide; membranes; encodes
AB THE major transforming protein of bovine papillomavirus type 1, E5 (refs 1-4), is mainly associated with endomembranes 5,6, specifically binding to a cellular protein of relative molecular mass 16,000 (16K) (ref. 7). At the same time as transformation, E5 causes the phosphorylation of tyrosine residues in epidermal and platelet-derived growth factor receptors 8,9.  We show here that the 16K protein associated with E5 is the 16K component of vacuolar ATPases. This protein is known to be an integral membrane protein in endosomes, bovine chromaffin granules, synaptic vesicles, fungal and plant vacuoles and clathrin-coated vesicles 10-16, as well as a component of gap-junction-like membrane complexes 17.  Because proton pumps are critical for the function of cellular compartments that process growth-factor receptors, the interaction of E5 with the 16K protein could explain the pleiomorphic features of cells transformed by E5.
C1 BEATSON INST CANC RES,GLASGOW G61 1BD,SCOTLAND.
C3 Beatson Institute
RP GOLDSTEIN, DJ (corresponding author), GEORGETOWN UNIV,DEPT PATHOL,WASHINGTON,DC 20007, USA.
NR 26
TC 175
Z9 188
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 347
EP 349
DI 10.1038/352347a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900075
PM 1649407
DA 2026-03-10
ER

PT J
AU ARMIJO, R
   LYONCAEN, H
   PAPANASTASSIOU, D
AF ARMIJO, R
   LYONCAEN, H
   PAPANASTASSIOU, D
TI A POSSIBLE NORMAL-FAULT RUPTURE FOR THE 464-BC SPARTA EARTHQUAKE
SO NATURE
LA English
DT Article
ID extension; greece; east
AB SURFACE ruptures have been identified for some normal-faulting earthquakes in the Aegean region 1-3, but for most historical earthquakes the associated faults are unknown.  This hampers the evaluation of the rates and styles of present-day deformation, and the assessment of seismic hazard in the region 4.  Here we examine the famous earthquake that destroyed Sparta in 464 BC.  Using SPOT satellite images and fieldwork, we have mapped a 20-km-long normal fault scarp trending approximately north-south, a few kilometres east of the ancient city.  Our observations, combined with an examination of historical descriptions of the earthquake damage, suggest that the Sparta earthquake ruptured this fault scarp in an event of magnitude M(s) almost-equal-to 7.2.  The Holocene slip rate and the recurrence time for such large events on the Sparta fault would be approximately 1 mm yr-1 and approximately 3,000 yr, respectively.
C1 NATL OBSERV,GR-11810 ATHENS,GREECE.
C3 National Observatory of Athens
RP ARMIJO, R (corresponding author), INST PHYS GLOBE,4 PL JUSSIEU,F-75252 PARIS 05,FRANCE.
NR 19
TC 49
Z9 53
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 137
EP 139
DI 10.1038/351137a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500046
DA 2026-03-10
ER

PT J
AU HODELL, DA
   CURTIS, JH
   JONES, GA
   HIGUERAGUNDY, A
   BRENNER, M
   BINFORD, MW
   DORSEY, KT
AF HODELL, DA
   CURTIS, JH
   JONES, GA
   HIGUERAGUNDY, A
   BRENNER, M
   BINFORD, MW
   DORSEY, KT
TI RECONSTRUCTION OF CARIBBEAN CLIMATE CHANGE OVER THE PAST 10,500 YEARS
SO NATURE
LA English
DT Article
ID lake-level fluctuations; last deglaciation; atlantic-ocean; ice-age; circulation; pleistocene; calibration; venezuela; valencia; holocene
AB SEDIMENT cores from low-latitude lakes provide some of the best records of tropical climate change since the late Pleistocene.  Here we report a high-resolution reconstruction of Caribbean climate based on O-18/O-16 ratios in ostracod shells from Lake Miragoane, Haiti.  Our results show that the climate was dry and the lake level low during the latter part of the Younger Dryas chronozone (10.5-10 kyr BP), but that water level in the lake rose at the end of the last deglaciation (approximately 10-7 kyr BP), reflecting the wetter conditions of the early Holocene which persisted for nearly 4,000 years.  Lake level declined at approximately 3.2 kyr BP with the onset of a drier climate which generally prevailed throughout the late Holocene.  These long-term changes in Caribbean climate are generally similar to those found for Africa over the same period, and can be largely explained by orbitally induced (Milankovitch) variations in seasonal insolation which modified the intensity of the annual cycle.  Superimposed on the orbitally forced climate trends are more abrupt climate events that result from complex, nonlinear interactions in the ocean-atmosphere system.  The interpretation of Antillean biogeography and the development of Caribbean and Mesoamerican culture must be considered in the context of such shifts in climate.
C1 WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543.
   UNIV FLORIDA,FLORIDA MUSEUM NAT HIST,GAINESVILLE,FL 32611.
   UNIV FLORIDA,DEPT FISHERIES & AQUACULTURE,GAINESVILLE,FL 32611.
   HARVARD UNIV,GRAD SCH DESIGN,CAMBRIDGE,MA 02138.
   KINNET LABS INC,SANTA CRUZ,CA 95060.
C3 Woods Hole Oceanographic Institution; State University System of Florida; University of Florida; State University System of Florida; University of Florida; Harvard University
RP HODELL, DA (corresponding author), UNIV FLORIDA,DEPT GEOL,GAINESVILLE,FL 32611, USA.
NR 33
TC 309
Z9 365
U1 1
U2 51
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 790
EP 793
DI 10.1038/352790a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400055
DA 2026-03-10
ER

PT J
AU DIETZ, HC
   CUTTING, GR
   PYERITZ, RE
   MASLEN, CL
   SAKAI, LY
   CORSON, GM
   PUFFENBERGER, EG
   HAMOSH, A
   NANTHAKUMAR, EJ
   CURRISTIN, SM
   STETTEN, G
   MEYERS, DA
   FRANCOMANO, CA
AF DIETZ, HC
   CUTTING, GR
   PYERITZ, RE
   MASLEN, CL
   SAKAI, LY
   CORSON, GM
   PUFFENBERGER, EG
   HAMOSH, A
   NANTHAKUMAR, EJ
   CURRISTIN, SM
   STETTEN, G
   MEYERS, DA
   FRANCOMANO, CA
TI MARFAN-SYNDROME CAUSED BY A RECURRENT DENOVO MISSENSE MUTATION IN THE FIBRILLIN GENE
SO NATURE
LA English
DT Article
ID dinucleotide repeat polymorphism; polymerase chain-reaction; dna polymorphisms; chromosome-15; duchenne; locus
AB MARFAN syndrome is an inherited disorder of connective tissue manifested in the ocular, skeletal and cardiovascular systems. It is inherited as an autosomal dominant with high penetrance, but has great clinical variability 1. Linkage studies have mapped the Marfan locus to chromosome 15q15-21.3 (refs 2, 3). There have been no reports of genetic heterogeneity in the syndrome. Following the identification of fibrillin (a glycoprotein component of the extracellular microfibril 4), immunohistopathological quantification of the protein in skin and fibroblast culture 5, and examination of fibrillin synthesis, extracellular transport, and incorporation into the extracellular matrix (D. M. Milewicz, R.E.P., E. S. Crawford and P.H. Byers, manuscript in preparation) have demonstrated abnormalities of fibrillin metabolism in most patients. A portion of the complementary DNA encoding fibrillin has been cloned 6 and mapped by in situ hybridization to chromosome 15 (ref. 7). Here we report that the fibrillin gene is linked to the Marfan phenotYPe (theta = 0.00; logarithm of the odds (lod) = (3.9) and describe a de novo missense mutation in the fibrillin gene in two patients with sporadic disease. We thus implicate fibrillin as the protein defective in patients with the Marfan syndrome.
C1 OREGON HLTH SCI UNIV, SHRINERS HOSP CRIPPLED CHILDREN, PORTLAND, OR 97201 USA.
   OREGON HLTH SCI UNIV, DEPT BIOCHEM & MOLEC BIOL, PORTLAND, OR 97201 USA.
   JOHNS HOPKINS UNIV, SCH MED, DEPT PEDIAT, CTR MED GENET, BALTIMORE, MD 21205 USA.
   JOHNS HOPKINS UNIV, SCH MED, DEPT MED, CTR MED GENET, BALTIMORE, MD 21205 USA.
   JOHNS HOPKINS UNIV, SCH MED, DEPT GYNECOL & OBSTET, CTR MED GENET, BALTIMORE, MD 21205 USA.
C3 Oregon Health & Science University; Oregon Health & Science University; Johns Hopkins University; Johns Hopkins University; Johns Hopkins University
RP DIETZ, HC (corresponding author), JOHNS HOPKINS UNIV, SCH MED, DEPT PEDIAT, DIV PEDIAT CARDIOL, BALTIMORE, MD 21205 USA.
NR 22
TC 1631
Z9 1815
U1 0
U2 147
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 337
EP 339
DI 10.1038/352337a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900071
PM 1852208
DA 2026-03-10
ER

PT J
AU RIGDEN, SM
   GWANMESIA, GD
   FITZ GERALD, JD
   JACKSON, I
   LIEBERMANN, RC
AF RIGDEN, SM
   GWANMESIA, GD
   FITZ GERALD, JD
   JACKSON, I
   LIEBERMANN, RC
TI SPINEL ELASTICITY AND SEISMIC STRUCTURE OF THE TRANSITION ZONE OF THE MANTLE
SO NATURE
LA English
DT Article
ID system mg2sio4-fe2sio4; pressure-dependence; wave velocity; olivine; discontinuity; polycrystals; beta-mg2sio4; california; beneath; phase
AB THERE is continuing debate about whether the upper mantle is chemically stratified, and whether the seismic discontinuity at 400 km depth represents a chemical boundary, a phase change of the (Mg, Fe)2SiO4 component from the alpha-phase (olivine) to the beta-phase, or a combination of both. Recent developments in high-pressure synthesis 1,2 and ultrasonic interferometry 3,4 have made possible measurements of elastic-wave velocities in small, polycrystalline samples of high-pressure phases. By combining our new acoustic measurements on the spinel (gamma) phase of Mg2 SiO4 With existing data for the alpha and beta-phases, we present here velocity profiles for the M2SiO4 Component of the mantle (where M represents Mg or Fe) to depths of about 600 km. We find it to be unlikely that any seismologically observable velocity discontinuity at about 520 km depth can be attributed to this component, although the contrast in impedance (the product of density and velocity) might be sufficient for the beta --> gamma-transformation to be observed in long-period seismic reflection studies at near-normal incidence 5. The velocity gradients in the transition zone, particularly for shear waves, are steeper than would be expected for simple adiabatic compression of likely mantle compositions, suggesting that alternative explanations including chemical heterogeneity and anelastic relaxation need to be explored.
C1 SUNY STONY BROOK, CTR HIGH PRESSURE RES, STONY BROOK, NY 11794 USA.
   SUNY STONY BROOK, DEPT EARTH & SPACE SCI, STONY BROOK, NY 11794 USA.
C3 State University of New York (SUNY) System; Stony Brook University; State University of New York (SUNY) System; Stony Brook University
RP RIGDEN, SM (corresponding author), AUSTRALIAN NATL UNIV, RES SCH EARTH SCI, GPO BOX 4, CANBERRA, ACT 2601, AUSTRALIA.
NR 26
TC 86
Z9 97
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 143
EP 145
DI 10.1038/354143a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000058
DA 2026-03-10
ER

PT J
AU BERNHOEFT, NR
   ALLEN, PJ
   PAUL, DM
   HAYDEN, SM
   TIMMINS, PA
   LONZARICH, GG
AF BERNHOEFT, NR
   ALLEN, PJ
   PAUL, DM
   HAYDEN, SM
   TIMMINS, PA
   LONZARICH, GG
TI ANOMALOUS NEUTRON-SCATTERING NEAR THE SUPERCONDUCTING PHASE-TRANSITION
SO NATURE
LA English
DT Article
ID fluctuation
AB THE inelastic scattering of low-energy neutrons near a second-order phase transition can provide a description of the spontaneous fluctuations in space and time of the physical parameter which, at low temperatures, enters a state of long-range order. Often the order parameter is coupled to the neutron directly, as in magnetic or lattice relaxation phenomena; as in the case of superconductivity, discussed here, the coupling is indirect. In either case, inelastic neutron diffraction measures the amplitude of the equilibrium fluctuations on an absolute scale, which may be compared with the predictions of models based on linear response theory 1. To this end, we report an investigation of the temperature dependence of small-angle neutron scattering in homogeneous bulk samples of the high-temperature superconductor YBa2Cu3O7-delta. An anomalous increase in the scattering intensity occurs near the superconducting phase transition, and at lower temperatures. These effects seem to be larger than can be accounted for in elementary models of the normal and superconducting states.
C1 UNIV WARWICK, DEPT PHYS, COVENTRY CV4 7AL, W MIDLANDS, ENGLAND.
   UNIV CAMBRIDGE, INTERDISCIPLINARY CTR SUPERCONDUCT, CAMBRIDGE CB3 0HE, ENGLAND.
   INST MAX VON LAUE PAUL LANGEVIN, F-38042 GRENOBLE, FRANCE.
   UNIV CAMBRIDGE, CAVENDISH LAB, CAMBRIDGE CB3 0HE, ENGLAND.
C3 University of Warwick; University of Cambridge; Institut Laue-Langevin (ILL); University of Cambridge
RP BERNHOEFT, NR (corresponding author), UNIV DURHAM, DEPT PHYS, S RD, DURHAM DH1 3LE, ENGLAND.
NR 13
TC 5
Z9 5
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 690
EP 692
DI 10.1038/350690a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000054
DA 2026-03-10
ER

PT J
AU KOHNEN, MEL
   DAMSTE, JSS
   DELEEUW, JW
AF KOHNEN, MEL
   DAMSTE, JSS
   DELEEUW, JW
TI BIASES FROM NATURAL SULFURIZATION IN PALEOENVIRONMENTAL RECONSTRUCTION BASED ON HYDROCARBON BIOMARKER DISTRIBUTIONS
SO NATURE
LA English
DT Article
ID organic-matter; sediments
AB BIOMARKERS (chemical fossils) are sedimentary organic compounds whose basic skeletons suggest an unambiguous link with known contemporary natural products, and were synthesized by biota present at the time of the deposition of the sediment. These compounds are commonly used to assess palaeoenvironmental conditions of deposition of Recent and ancient sediments 1-3. Saturated hydrocarbons are relatively easy to analyse and contain a lot of geochemical information, and are therefore the most widely used class of biomarkers in palaeoenvironmental reconstruction 2-5. Hydrocarbon biomarkers are biosynthesized as such or are derived from functionalized biosynthetic lipids, such as alkenes, alcohols and acids, by diagenetically induced defunctionalization. Functionalized lipids may, however, also undergo an abiogenic reaction with hydrogen sulphide or polysulphides ('natural sulphurization') during the early stages of diagenesis, and this may lead to selective removal of specific hydrocarbon biomarker precursors. Here we investigate the influence of natural sulphurization on hydrocarbon biomarker signatures in immature sediments from Italy and off Peru. We show that, if not taken properly into account, this process may lead to a severe bias in the interpretation of the geological record.
RP KOHNEN, MEL (corresponding author), DELFT UNIV TECHNOL, FAC CHEM TECHNOL & MAT SCI, ORGAN GEOCHEM UNIT, DEVRIES VANHEYSTPLANTSOER 2, 2628 RZ DELFT, NETHERLANDS.
NR 29
TC 129
Z9 139
U1 0
U2 15
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 775
EP 778
DI 10.1038/349775a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600050
DA 2026-03-10
ER

PT J
AU NODA, I
AF NODA, I
TI LATEX ELASTOMER WITH A PERMANENTLY HYDROPHILIC SURFACE
SO NATURE
LA English
DT Article
ID polyethylene
AB WATER wettability is important in many applications of polymeric materials, including fabrics, printing and biomedical uses 1,2.  Various surface-modification techniques are available to convert the intrinsically hydrophobic surfaces of plastic to water-wettable ones, by incorporating chemically polar functional groups at the surface 4-7.  Although such chemically induced surface hydrophilicity can be relatively long-lived while the substrates remain rigid, increases in the mobility of surface molecules, for example, due to increasing temperature, can cause rapid loss of hydrophilicity, driven by the tendency of surfaces to minimize their free energy 2-5.  As the polar groups are not often bound to the polymer matrix (usually being instead free surfactant molecules), they may also be flushed from the surface by repeated exposure to water.  Here I report the preparation of permanently water-wettable elastomeric films from a latex synthesized by polymerization of monomers in the presence of an amphiphilic block copolymer.  By migration of the hydrophilic segments to the surface during film formation, the film is rendered essentially completely wettable by water.  Applications may include flexible coatings that can introduce spatially selective wettability to solid surfaces, for example one-side wettable perforated films used for bandages and disposable diapers 8.
RP NODA, I (corresponding author), PROCTER & GAMBLE CO,MIAMI VALLEY LABS,POB 398707,CINCINNATI,OH 45239, USA.
NR 8
TC 22
Z9 22
U1 0
U2 19
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 143
EP 144
DI 10.1038/350143a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500053
DA 2026-03-10
ER

PT J
AU BEIER, JA
   WAKEHAM, SG
   PILSKALN, CH
   HONJO, S
AF BEIER, JA
   WAKEHAM, SG
   PILSKALN, CH
   HONJO, S
TI ENRICHMENT IN SATURATED COMPOUNDS OF BLACK-SEA INTERFACIAL SEDIMENT
SO NATURE
LA English
DT Article
ID particulate matter; geochemistry; ocean; water
AB THE sediment/water interface of the ocean should consist of organic compounds produced both in the overlying water column and during early diagenesis 1-5.  We have found that the uppermost approximately 1 mm of sediment samples obtained from the Black Sea are enriched in saturated sterols and fatty acids relative to both suspended particles and underlying sediments.  We speculate that either this 'floc' layer contains a microbial community capable of yielding a distribution of compounds that is high in saturated species, or the floc accumulates low-density, fine material enriched in saturated components produced in the water column 6.  Saturated components would thus be formed or concentrated very early during sedimentation and diagenesis.  This has important implications for hydrogenation rates in geological environments, and may cast light on the way in which biological materials, rich in unsaturated compounds, become converted into sediments, petroleum and source rocks that contain predominantly saturated compounds.
C1 SKIDAWAY INST OCEANOG,SAVANNAH,GA 31416.
   MONTEREY BAY AQUARIUM RES INST,MONTEREY,CA 93950.
   WOODS HOLE OCEANOG INST,DEPT GEOL & GEOPHYS,WOODS HOLE,MA 02543.
C3 University System of Georgia; University of Georgia; Skidaway Institute of Oceanography; Monterey Bay Aquarium Research Institute; Woods Hole Oceanographic Institution
NR 18
TC 17
Z9 17
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 642
EP 644
DI 10.1038/351642a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200062
DA 2026-03-10
ER

PT J
AU ZHAO, JH
   GOSS, WM
   LO, KY
   EKERS, RD
AF ZHAO, JH
   GOSS, WM
   LO, KY
   EKERS, RD
TI HIGH-RESOLUTION VLA IMAGES OF THE GALACTIC-CENTER AT 2-CM WAVELENGTH WITH LARGE DYNAMIC-RANGE
SO NATURE
LA English
DT Article
ID interstellar bubbles; radio-source
AB THE existence of a black hole at the centre of our galaxy was proposed by Lynden-Bell and Rees 1, and the later discovery of a bright compact radio source (Sgr A*) at the Galactic Centre 2 suggested the presence of a central exciting source 3. Recently, Yusef-Zadeh et al. 4 reported faint extended radio structures (the 'satellite radio features') which they interpreted as thermally emitting blobs of plasma physically associated with Sgr A*. These puzzling features could be taken as evidence for an outflowing wind from Sgr A*/IRS16 (a complex infrared source), but there was also a suspicion that they might be instrumental artefacts. We have re-observed the Galactic Centre using the Very Large Array, obtaining images at a wavelength of 2 cm with resolution of approximately 0.1 arcsec (0.005 pc). The r.m.s. noise of 70-mu-Jy per beam, with a dynamic range of 22,000: 1, is comparable to that of ref. 4, but the new structures reported in ref. 4 do not appear in our observations. We discuss several ways that low-level artefacts near Sgr A* might have been generated. We also confirm the presence of a plume of emission 1 arcsec southwest of Sgr A*.
C1 UNIV ILLINOIS,DEPT ASTRON,URBANA,IL 61801.
   AUSTRALIA TELESCOPE NATL FAC,EPPING,NSW 2121,AUSTRALIA.
C3 University of Illinois System; University of Illinois Urbana-Champaign; Commonwealth Scientific & Industrial Research Organisation (CSIRO); Australia Telescope National Facility
RP ZHAO, JH (corresponding author), NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801, USA.
NR 24
TC 16
Z9 16
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 46
EP 48
DI 10.1038/354046a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900051
DA 2026-03-10
ER

PT J
AU JACOBS, GH
   NEITZ, J
   DEEGAN, JF
AF JACOBS, GH
   NEITZ, J
   DEEGAN, JF
TI RETINAL RECEPTORS IN RODENTS MAXIMALLY SENSITIVE TO ULTRAVIOLET-LIGHT
SO NATURE
LA English
DT Article
ID spectral sensitivity; photosensitivity; sciureus; monkeys; saimiri; system; rat
AB HIGH sensitivity to near-ultraviolet light is a fundamental feature of vision in many invertebrates 1,2. Among vertebrates there are some amphibians, birds and fishes that are also sensitive to near-ultraviolet wavelengths 3-6. This sensitivity can be achieved through a class of cone photoreceptor containing an ultraviolet-sensitive pigment 7-9. Although these receptors were thought not to exist in the eyes of mammals, we now report that some rodents have a retinal mechanism that is maximally sensitive to ultraviolet light.
RP JACOBS, GH (corresponding author), UNIV CALIF SANTA BARBARA,DEPT PSYCHOL,SANTA BARBARA,CA 93106, USA.
NR 20
TC 348
Z9 396
U1 1
U2 37
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 655
EP 656
DI 10.1038/353655a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200068
PM 1922382
DA 2026-03-10
ER

PT J
AU ROWANROBINSON, M
   BROADHURST, T
   LAWRENCE, A
   MCMAHON, RG
   LONSDALE, CJ
   OLIVER, SJ
   TAYLOR, AN
   HACKING, PB
   CONROW, T
   SAUNDERS, W
   ELLIS, RS
   EFSTATHIOU, GP
   CONDON, JJ
AF ROWANROBINSON, M
   BROADHURST, T
   LAWRENCE, A
   MCMAHON, RG
   LONSDALE, CJ
   OLIVER, SJ
   TAYLOR, AN
   HACKING, PB
   CONROW, T
   SAUNDERS, W
   ELLIS, RS
   EFSTATHIOU, GP
   CONDON, JJ
TI A HIGH-REDSHIFT IRAS GALAXY WITH HUGE LUMINOSITY - HIDDEN QUASAR OR PROTOGALAXY
SO NATURE
LA English
DT Article
ID s5 0014+81; remnant
AB DURING a survey intended to measure redshifts for 1,400 galaxies identified with faint sources detected by the Infrared Astronomy Satellite, we found an emission-line galaxy at a redshift of 2.286, and with the enormous far-infrared luminosity of 3 x 10(14) times that of the Sun (L.). The spectrum is very unusual, showing lines of high excitation but with very weak Lyman-alpha emission. A self-absorbed synchrotron model for the infrared energy distribution cannot be ruled out, but a thermal origin seems more plausible. A radio-quiet quasar embedded in a very dusty galaxy could account for the infrared emission, as might a starburst embedded in 1-10 x 10(9) M. of dust. The latter case demands so much dust that the object would probably be a massive galaxy in the. process of formation. In either case, this is a remarkable object, and the presence of a large amount of dust in an object of such high redshift implies the generation of heavy elements at an early cosmological epoch.
C1 QUEEN MARY & WESTFIELD COLL, DEPT PHYS, LONDON E1 4NS, ENGLAND.
   UNIV CAMBRIDGE, INST ASTRON, CAMBRIDGE CB3 0HA, ENGLAND.
   CALTECH, CTR INFRARED PROC & ANAL, PASADENA, CA 91125 USA.
   CALTECH, JET PROP LAB, PASADENA, CA 91109 USA.
   UNIV OXFORD, DEPT ASTROPHYS, OXFORD OX1 3RH, ENGLAND.
   UNIV DURHAM, DEPT PHYS, DURHAM DH1 3LE, ENGLAND.
   NATL RADIO ASTRON OBSERV, CHARLOTTESVILLE, VA 22903 USA.
C3 University of London; Queen Mary University London; University of Cambridge; California Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; University of Oxford; Durham University; National Radio Astronomy Observatory (NRAO)
RP ROWANROBINSON, M (corresponding author), QUEEN MARY & WESTFIELD COLL, SCH MATH SCI, MILE END RD, LONDON E1 4NS, ENGLAND.
NR 19
TC 251
Z9 257
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 719
EP 721
DI 10.1038/351719a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100054
DA 2026-03-10
ER

PT J
AU WANG, H
   KAVANAUGH, MP
   NORTH, RA
   KABAT, D
AF WANG, H
   KAVANAUGH, MP
   NORTH, RA
   KABAT, D
TI CELL-SURFACE RECEPTOR FOR ECOTROPIC MURINE RETROVIRUSES IS A BASIC-AMINO-ACID TRANSPORTER
SO NATURE
LA English
DT Article
ID envelope glycoprotein; leukemia virus; saccharomyces-cerevisiae; gene; interference; membrane; erythroleukemia; expression; infection; proteins
AB THE complementary DNA sequence encoding the cell-surface receptor for ecotropic host-range murine retroviruses (ecoR) shows that it contains 622 amino acids and 14 hydrophobic potentially membrane-spanning sequences 1. Because this receptor occurs on many or all murine cells 2 and is probably essential for viability of cultured fibroblasts 3, its normal function might be to transport an essential metabolite. We expressed ecoR in Xenopus laevis oocytes by injecting RNA transcribed from the cloned cDNA. These oocytes specifically bound the gp70 envelope glycoprotein from an ecotropic murine leukaemia virus. An inward current was recorded electrophysiologically when a mixture of amino-acids was applied: this resulted from a stereoselective, saturable uptake of lysine, arginine and ornithine; it was independent of sodium and not substantially altered by gp70. Cysteine and homoserine were also taken up, but sodium was necessary for their transport. These properties of ecoR correspond to those of the y+ amino-acid transporter 4-6. Our results demonstrate the subversion of a ubiquitous cell membrane protein, in this case a basic amino acid transporter, for use as a retroviral receptor.
C1 OREGON HLTH SCI UNIV, VOLLUM INST, PORTLAND, OR 97201 USA.
C3 Oregon Health & Science University
RP WANG, H (corresponding author), OREGON HLTH SCI UNIV, DEPT BIOCHEM, PORTLAND, OR 97201 USA.
NR 31
TC 402
Z9 434
U1 0
U2 9
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 729
EP 731
DI 10.1038/352729a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400063
PM 1908564
DA 2026-03-10
ER

PT J
AU CHOI, YW
   KAPPLER, JW
   MARRACK, P
AF CHOI, YW
   KAPPLER, JW
   MARRACK, P
TI A SUPERANTIGEN ENCODED IN THE OPEN READING FRAME OF THE 3' LONG TERMINAL REPEAT OF MOUSE MAMMARY-TUMOR VIRUS
SO NATURE
LA English
DT Article
ID major histocompatibility complex; t-cell recognition; gene-products; mls-locus; region; expression; receptor; sequence; tolerance; antigens
AB Mice express a collection of superantigens, which bind to class II major histocompatibility proteins and interact with T cells bearing particular V-beta chains as part of their alpha-beta-receptors.  These superantigens have been suggested to be encoded by exogenous or endogenous mouse mammary tumour viruses.  One such superantigen is now shown to be encoded in the open reading frame of the long terminal repeat of a mammary tumour virus, a gene of previously unknown function.
C1 UNIV COLORADO,HLTH SCI CTR,DEPT MICROBIOL & IMMUNOL,DENVER,CO 80262.
   UNIV COLORADO,HLTH SCI CTR,DEPT MED,DENVER,CO 80262.
   UNIV COLORADO,HLTH SCI CTR,DEPT BIOCHEM BIOPHYS & GENET,DENVER,CO 80262.
C3 University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus; University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus; University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus
RP CHOI, YW (corresponding author), NATL JEWISH CTR IMMUNOL & RESP MED,HOWARD HUGHES MED INST,DEPT MED,DIV BASIC IMMUNOL,DENVER,CO 80206, USA.
NR 52
TC 416
Z9 432
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 203
EP 207
DI 10.1038/350203a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900046
PM 1706480
DA 2026-03-10
ER

PT J
AU LEGRAND, M
   FENIETSAIGNE, C
   SALTZMAN, ES
   GERMAIN, C
   BARKOV, NI
   PETROV, VN
AF LEGRAND, M
   FENIETSAIGNE, C
   SALTZMAN, ES
   GERMAIN, C
   BARKOV, NI
   PETROV, VN
TI ICE-CORE RECORD OF OCEANIC EMISSIONS OF DIMETHYLSULFIDE DURING THE LAST CLIMATE CYCLE
SO NATURE
LA English
DT Article
ID antarctic ice; sulfur; phytoplankton; acid; ions; snow
AB THE Vostok ice core in Antarctica has provided one of the longest climate records, enabling the stable-isotope, major-ion and gas composition of the atmosphere to be reconstructed over many thousands of years.  Here we present depth profiles along this core of methanesulphonate and non-seasalt sulphate (produced by the atmospheric oxidation of dimethylsulphide), which provide the first historical record of biogenic sulphur emissions from the Southern Hemisphere oceans over a complete glacial-interglacial cycle (160 kyr).   Those measurements confirm and extend some previous observations made on a very limited data set from the Dome C ice core in Antarctica, which indicated increased oceanic emissions of dimethylsulphide during the later stages of the glacial period, compared with the present day 1.  The observed glacial-interglacial variations in methanesulphonate and non-seasalt sulphate confirm that the ocean-atmosphere sulphur cycle is extremely sensitive to climate change.
C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149.
   ARCTIC & ANTARCTIC RES INST,LENINGRAD 199226,USSR.
C3 University of Miami; Arctic & Antarctic Research Institute
RP LEGRAND, M (corresponding author), LAB GLACIOL & GEOPHYS ENVIRONNEMENT,BP 96,F-38402 ST MARTIN DHERES,FRANCE.
NR 19
TC 162
Z9 176
U1 0
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 144
EP 146
DI 10.1038/350144a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500054
DA 2026-03-10
ER

PT J
AU HILL, RE
   FAVOR, J
   HOGAN, BLM
   TON, CCT
   SAUNDERS, GF
   HANSON, IM
   PROSSER, J
   JORDAN, T
   HASTIE, ND
   VANHEYNINGEN, V
AF HILL, RE
   FAVOR, J
   HOGAN, BLM
   TON, CCT
   SAUNDERS, GF
   HANSON, IM
   PROSSER, J
   JORDAN, T
   HASTIE, ND
   VANHEYNINGEN, V
TI MOUSE SMALL EYE RESULTS FROM MUTATIONS IN A PAIRED-LIKE HOMEOBOX-CONTAINING GENE
SO NATURE
LA English
DT Article
ID developing excretory system; box; drosophila; deletion; domain; pax-1; oct-1; dna
AB SMALL eye (Sey) in mouse is a semidominant mutation which in the homozygous condition results in the complete lack of eyes and nasal primordia. On the basis of comparative mapping studies and on phenotypic similarities, Sey bas been suggested to be homologous to congenital aniridia (lack of iris) in human 1,2.  A candidate gene for the aniridia (AN) locus at 11p13 bas been isolated by positional cloning 3 and its sequence and that of the mouse homologue has been established (C.T., manuscript in preparation). This gene belongs to the paired-like class of developmental genes first described in Drosophila which contain two highly conserved motifs, the paired box and the homeobox 4,5.  In vertebrates, genes which encode the single paired domain as well as those which express both motifs have been described as the Pax multigene family 6-10.  A Pax gene recently described as Pax-6 11,12 is identical to the mouse homologue of the candidate aniridia gene. Here we report the analysis of three independent Sey alleles and show that indeed this gene is mutated and that the mutations would predictably interrupt gene function.
C1 GESELL STRAHLEN & UMWELTFORSCH MBH,INST SAUGETIERGENET,W-8042 NEUHERBERG,GERMANY.
   UNIV TEXAS,MD ANDERSON CANC CTR,DEPT BIOCHEM & MOLEC BIOL,HOUSTON,TX 77030.
C3 University of Texas System; UTMD Anderson Cancer Center
RP HILL, RE (corresponding author), WESTERN GEN HOSP,MRC,HUMAN GENET UNIT,CREWE RD,EDINBURGH EH4 2XU,MIDLOTHIAN,SCOTLAND.
NR 37
TC 1202
Z9 1330
U1 0
U2 47
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 522
EP 525
DI 10.1038/354522a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100014
PM 1684639
DA 2026-03-10
ER

PT J
AU KIRCHMAN, DL
   SUZUKI, Y
   GARSIDE, C
   DUCKLOW, HW
AF KIRCHMAN, DL
   SUZUKI, Y
   GARSIDE, C
   DUCKLOW, HW
TI HIGH TURNOVER RATES OF DISSOLVED ORGANIC-CARBON DURING A SPRING PHYTOPLANKTON BLOOM
SO NATURE
LA English
DT Article
ID heterotrophic bacteria; nitrogen; seawater; matter; growth; pacific
AB OCEANIC dissolved organic carbon (DOC) is one of the Earth's largest carbon reservoirs, but until recently its role in the carbon cycle has been neglected. New methodology 1, however, has led to larger estimates of DOC concentrations and also to renewed interest in the biochemical lability of DOC 2. Previous work found that the mean age of DOC in the surface ocean was > 1,000 years 3. To examine the lability of DOC in greater detail, we have conducted experiments to estimate DOC turnover rates in the upper ocean. We directly observed rapid DOC turnover by bacterioplankton during the spring phytoplankton bloom in the North Atlantic ocean. Potential turnover rates, measured in 0.8-mu-m filtered samples, ranged from 0.025 to 0.363 per day, and were consistent with bacterial biomass production and uptake of dissolved nitrogen (NH4+, NO3- and urea). Our results indirectly suggest that cycling of dissolved organic nitrogen (DON) differs from that of DOC. The high estimates of DOC concentrations and turnover rates repeated here, if found to be general, would seem to demand changes in models 4 of Carbon cycling and of the ocean's role in buffering increases in atmospheric CO2.
C1 BIGELOW LAB,BOOTHBAY HARBOR,ME 04575.
   UNIV MARYLAND,HORN POINT ENVIRONM LAB,CAMBRIDGE,MD 21613.
   METEOROL RES INST,GEOCHEM LAB,TSUKUBA,IBARAKI 305,JAPAN.
C3 Bigelow Laboratory for Ocean Sciences; Meteorological Research Institute - Japan
RP KIRCHMAN, DL (corresponding author), UNIV DELAWARE,COLL MARINE STUDIES,LEWES,DE 19958, USA.
NR 29
TC 376
Z9 421
U1 1
U2 89
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 612
EP 614
DI 10.1038/352612a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100052
DA 2026-03-10
ER

PT J
AU LUISI, BF
   XU, WX
   OTWINOWSKI, Z
   FREEDMAN, LP
   YAMAMOTO, KR
   SIGLER, PB
AF LUISI, BF
   XU, WX
   OTWINOWSKI, Z
   FREEDMAN, LP
   YAMAMOTO, KR
   SIGLER, PB
TI CRYSTALLOGRAPHIC ANALYSIS OF THE INTERACTION OF THE GLUCOCORTICOID RECEPTOR WITH DNA
SO NATURE
LA English
DT Article
ID transcription factor-iiia; steroid-hormone receptor; target gene specificity; zinc-binding domains; mammary-tumor virus; crystal-structure; estrogen-receptor; response element; amino-acids; resolution
AB Two crystal structures of the glucocorticoid receptor DNA-binding domain complexed with DNA are reported. The domain has a globular fold which contains two Zn-nucleated substructures of distinct conformation and function. When it binds DNA, the domain dimerizes, placing the subunits in adjacent major grooves. In one complex, the DNA has the symmetrical consensus target sequence; in the second, the central spacing between the target's half-sites is larger by one base pair. This results in one subunit interacting specifically with the consensus target half-site and the other nonspecifically with a noncognate element. The DNA-induced dimer fixes the separation of the subunits' recognition surfaces so that the spacing between the half-sites becomes a critical feature of the target sequence's identity.
C1 YALE UNIV,DEPT MOLEC BIOPHYS & BIOCHEM,NEW HAVEN,CT 06511.
   YALE UNIV,HOWARD HUGHES MED INST,NEW HAVEN,CT 06511.
   UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143.
C3 Yale University; Yale University; Howard Hughes Medical Institute; University of California System; University of California San Francisco
NR 55
TC 1314
Z9 1461
U1 0
U2 53
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 497
EP 505
DI 10.1038/352497a0
PG 9
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600052
PM 1865905
DA 2026-03-10
ER

PT J
AU HOFFMAN, KA
AF HOFFMAN, KA
TI LONG-LIVED TRANSITIONAL STATES OF THE GEOMAGNETIC-FIELD AND THE 2 DYNAMO FAMILIES
SO NATURE
LA English
DT Article
ID matuyama polarity transition; french-polynesia; paleomagnetic data; volcanic islands; reversal models; records; geodynamo; sequence; configurations; morphology
AB Palaeomagnetic data from lavas produced at the Hawaii and Society Islands hotspots suggest that one or more specific, long-lived field configurations recur during successive polarity reversals spanning perhaps several million years. The apparent quasi-stationarity of these states and the relative placement of the two recording sites offer a rare opportunity to explore the fundamental geometrical properties of transitional fields.
RP HOFFMAN, KA (corresponding author), CALIF POLYTECH STATE UNIV SAN LUIS OBISPO,DEPT PHYS,SAN LUIS OBISPO,CA 93407, USA.
NR 46
TC 60
Z9 62
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 273
EP 277
DI 10.1038/354273a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400037
DA 2026-03-10
ER

PT J
AU BENDELAC, A
   SCHWARTZ, RH
AF BENDELAC, A
   SCHWARTZ, RH
TI CD4+ AND CD8+ T-CELLS ACQUIRE SPECIFIC LYMPHOKINE SECRETION POTENTIALS DURING THYMIC MATURATION
SO NATURE
LA English
DT Article
ID monoclonal-antibody; mouse thymocytes; stem-cells; expression; il-4; subsets; precursors; definition; receptors; profiles
AB PERIPHERAL CD4+ and CD8+ T lymphocytes carry out different functions during immune reactions, partly as a result of the distinct patterns of lymphokines that they secrete upon stimulation. Using thymic cells from adult and newborn mice as well as from fetal organ cultures, we show here that this functional differentiation occurs inside the thymus and is completed during the single positive stage by the time the T-cell receptor becomes fully coupled to the intracellular activation pathways leading to lymphokine secretion. Surprisingly, CD4+8- thymocytes differ from their immediate progeny, naive peripheral CD4+ cells, in that they secrete a broader range of lymphokines, including interleukins 4, 5 and 10 and gamma-interferon, and more closely resemble immunologically experienced (activated or memory) CD4+ lymphocytes.
RP BENDELAC, A (corresponding author), NIAID,CELLULAR & MOLEC IMMUNOL LAB,9000 ROCKVILLE PIKE,BETHESDA,MD 20892, USA.
NR 30
TC 178
Z9 188
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 68
EP 71
DI 10.1038/353068a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500059
PM 1831881
DA 2026-03-10
ER

PT J
AU HASSELL, MP
   COMINS, HN
   MAY, RM
AF HASSELL, MP
   COMINS, HN
   MAY, RM
TI SPATIAL STRUCTURE AND CHAOS IN INSECT POPULATION-DYNAMICS
SO NATURE
LA English
DT Article
ID predator prey interactions; systems-analysis; stability; models; aggregation
AB MOST environments are spatially subdivided, or patchy, and there has been much interest in the relationship between the dynamics of populations at the local and regional (metapopulation) scales 1. Here we study mathematical models for host-parasitoid interactions, where in each generation specified fractions (mu-N and mu-P, respectively) of the host and parasitoid subpopulations in each patch move to adjacent patches; in most previous work, the movement is not localized but is to any other patch 2. These simple and biologically sensible models with limited diffusive dispersal exhibit a remarkable range of dynamic behaviour: the density of the host and parasitoid subpopulations in a two-dimensional array of patches may exhibit complex patterns of spiral waves or spatially chaotic variation, they may show static 'crystal lattice' patterns, or they may become extinct. This range of behaviour is obtained with the local dynamics being deterministically unstable, with a constant host reproductive rate and no density dependence in the movement patterns. The dynamics depend on the host reproductive rate, and on the values of the parameters mu-N and mu-P. The results are relatively insensitive to the details of the interactions; we get essentially the same results from the mathematically-explicit Nicholson-Bailey model of host-parasitoid interactions, and from a very general 'cellular automaton' model in which only qualitative rules are specified. We conclude that local movement in a patchy environment can help otherwise unstable host and parasitoid populations to persist together, but that the deterministically generated spatial patterns in population density can be exceedingly complex (and sometimes indistinguishable from random environmental fluctuations).
C1 UNIV LONDON IMPERIAL COLL SCI & TECHNOL, CTR POPULAT BIOL, ASCOT SL5 7PY, BERKS, ENGLAND.
   UNIV OXFORD, DEPT ZOOL, OXFORD OX1 3PS, ENGLAND.
C3 Imperial College London; University of Oxford
RP HASSELL, MP (corresponding author), UNIV LONDON IMPERIAL COLL SCI & TECHNOL, DEPT BIOL, SILWOOD PK, ASCOT SL5 7PY, BERKS, ENGLAND.
NR 22
TC 695
Z9 767
U1 0
U2 141
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 255
EP 258
DI 10.1038/353255a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400058
DA 2026-03-10
ER

PT J
AU DILORIO, MS
   YOSHIZUMI, S
   MAUNG, M
   YANG, KY
   ZHANG, J
   FAN, NQ
AF DILORIO, MS
   YOSHIZUMI, S
   MAUNG, M
   YANG, KY
   ZHANG, J
   FAN, NQ
TI MANUFACTURABLE LOW-NOISE SQUIDS OPERATING IN LIQUID-NITROGEN
SO NATURE
LA English
DT Article
ID junction dc squids; magnetometers; optimization
AB THE superconducting quantum interference device (SQUID) holds promise for a wide range of applications, including the measurement of magnetic fields generated by the brain and heart, detection of tiny cracks and corrosion currents, and exploration of oil and mineral deposits. Currently available SQUIDs rely on low-transition-temperature (low-T(c)) superconductors, and must therefore be refrigerated to liquid-helium temperature (4.2 K). This difficult cryogenic requirement has presented a barrier to the widespread implementation of SQUID technology. We report here on the development of a high-T(c) d.c. SQUID with a noise level in liquid nitrogen (77 K) that is a significant improvement, at frequencies of practical interest, for SQUIDs produced by a manufacturable fabrication process 1,2.  The energy sensitivity of 1.6 x 10(-29) J Hz-1 at 10 Hz is comparable to the best previously reported 3 for any high-T(c) SQUID at 77 K. These high-T(c) SQUIDs are sensitive enough for many of the applications presently possible only with liquid helium devices.
RP DILORIO, MS (corresponding author), BIOMAGNET TECHNOL INC,9727 PACIFIC HTS BLVD,SAN DIEGO,CA 92121, USA.
NR 17
TC 19
Z9 20
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 513
EP 515
DI 10.1038/354513a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100010
DA 2026-03-10
ER

PT J
AU REITNER, A
   SHARPE, LT
   ZRENNER, E
AF REITNER, A
   SHARPE, LT
   ZRENNER, E
TI IS COLOR-VISION POSSIBLE WITH ONLY RODS AND BLUE-SENSITIVE CONES
SO NATURE
LA English
DT Article
ID spectral sensitivity; achromatopsia; monochromacy
AB AT night all cats are grey, but with the approach of dawn they take on colour.  By starlight, a single class of photoreceptors, the rods, function, whereas by daylight, three classes, the blue-, green- and red-sensitive cones, are active and provide colour vision.  Only by comparing the rates of quantal absorption in more than one photoreceptor class is colour vision possible.  Although the comparisons generally take place between the cones, they can involve the rods as well 1-4.  Here we investigate the wavelength discrimination of an extremely rare group of individuals, blue-cone monochromats, who have only rods and one class of cones 5-8.  We find that these individuals can distinguish wavelengths (440 to 500 nm) in the twilight region where the rods and blue-sensitive cones are simultaneously active.
C1 UNIV FREIBURG,NEUROL KLIN,W-7800 FREIBURG,GERMANY.
   UNIV TUBINGEN,HOSP EYE,DEPT PATHOPHYSIOL VIS & NEUROOPHTHALMOL,W-7400 TUBINGEN 1,GERMANY.
C3 University of Freiburg; Eberhard Karls University of Tubingen
RP REITNER, A (corresponding author), ZWEITE UNIV VIENNA,AUGENKLIN,ALSERSTR 4,A-1090 VIENNA,AUSTRIA.
NR 29
TC 82
Z9 94
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 798
EP 800
DI 10.1038/352798a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400058
PM 1881435
DA 2026-03-10
ER

PT J
AU LEE, CC
   PEARLMAN, JA
   CHAMBERLAIN, JS
   CASKEY, CT
AF LEE, CC
   PEARLMAN, JA
   CHAMBERLAIN, JS
   CASKEY, CT
TI EXPRESSION OF RECOMBINANT DYSTROPHIN AND ITS LOCALIZATION TO THE CELL-MEMBRANE
SO NATURE
LA English
DT Article
ID protein product; muscle; gene; myofibers; efficient; mice
AB DUCHENNE'S muscular dystrophy (DMD) is an X-linked progressive myopathy caused by a defect in the DMD gene locus 1,2.  The gene corresponding to the DMD locus produces a 14-kilobase (kb) messenger RNA that codes for a large cytoskeletal membrane protein, dystrophin 3,4.  DMD and Becker's muscular dystrophy are the consequences of dystrophin mutations 4,5.  The exact biological function of dystrophin remains unknown but it has been demonstrated that it is localized to the cytoplasmic face of the cell membrane and has direct interaction with several other membrane proteins 6,7.  We report here the synthesis of a 14-kb full-length complementary DNA for the mouse muscle dystrophin mRNA and the expression of this cDNA in COS cells.  The recombinant dystrophin is indistinguishable from mouse muscle dystrophin by western blot analysis with anti-dystrophin antibodies and was shown by an immunofluorescent technique to be localized in the cell membrane.  Our successful construction of a functional full-length cDNA opens opportunities for the study of structure and function of dystrophin and provides an opportunity to initiate gene therapy studies.
C1 BAYLOR UNIV,INST MOLEC GENET,HOUSTON,TX 77030.
   BAYLOR UNIV,HOWARD HUGHES MED INST,HOUSTON,TX 77030.
C3 Baylor University; Baylor College of Medicine; Baylor University; Howard Hughes Medical Institute
NR 20
TC 82
Z9 85
U1 2
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 334
EP 336
DI 10.1038/349334a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100054
PM 1824797
DA 2026-03-10
ER

PT J
AU WEISS, MR
AF WEISS, MR
TI FLORAL COLOR CHANGES AS CUES FOR POLLINATORS
SO NATURE
LA English
DT Article
ID fruit displays; flowers; plants
AB PLANTS have evolved traits that enable them to influence directly the behaviour and movement of their pollinators. Here I show that flowers in at least 74 diverse angiosperm families undergo dramatic, often localized, colour changes which direct the movements of a variety of pollinators to the benefit of both participants. Floral colour change was first noted almost 200 years ago 1 and is known in a variety of species 2-17, but the prevalence and significance of the phenomenon have gone largely unrecognized. I find that retention of older flowers increases a plant's attractiveness to pollinators from a distance, that pollinators discriminate between floral colour phases at close range, and that the discrimination involves learning. The phenomenon of floral colour change is taxonomically widespread, morphologically variable (Fig. 1), and physiologically diverse. It has evolved independently in the angiosperms many times and provides a striking example of functional convergence.
RP WEISS, MR (corresponding author), UNIV CALIF BERKELEY,DEPT INTEGRAT BIOL,BERKELEY,CA 94720, USA.
NR 27
TC 240
Z9 294
U1 2
U2 159
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 227
EP 229
DI 10.1038/354227a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800048
DA 2026-03-10
ER

PT J
AU WALLACE, MR
   ANDERSEN, LB
   SAULINO, AM
   GREGORY, PE
   GLOVER, TW
   COLLINS, FS
AF WALLACE, MR
   ANDERSEN, LB
   SAULINO, AM
   GREGORY, PE
   GLOVER, TW
   COLLINS, FS
TI A DENOVO ALU INSERTION RESULTS IN NEUROFIBROMATOSIS TYPE-1
SO NATURE
LA English
DT Article
ID gene; recombination; mutations; sequence; deletion; repeats
AB NEUROFIBROMATOSIS type 1 (NF1) is a common autosomal dominant disorder with a high mutation rate and variable expression, characterized by neurofibromas, cafe-au-lait spots, Lisch nodules of the iris, and less frequent features including bone deformities and learning disabilities 1. The recently cloned NF1 gene encodes a transcript of 13 kilobases from a ubiquitously expressed locus on chromosome 17 (refs. 2-4). Most NF1 patients are expected to have unique mutations, but only a few have so far been characterized, restricting genetic and functional information and the design of DNA diagnostics. We report an unusual NF1 mutation, that of a de novo Alu repetitive element insertion into an intron, which results in deletion of the downstream exon during splicing and consequently shifts the reading frame. This previously undescribed mechanism of mutation indicates that Alu retrotransposition is an ongoing process in the human germ line.
C1 UNIV MICHIGAN,HOWARD HUGHES MED INST,4570 MSRB 11,1150 W MED CTR DR,ANN ARBOR,MI 48109.
   UNIV MICHIGAN,DEPT INTERNAL MED & HUMAN GENET,ANN ARBOR,MI 48109.
   UNIV MICHIGAN,DEPT PEDIAT & COMMUNICABLE DIS,ANN ARBOR,MI 48109.
C3 Howard Hughes Medical Institute; University of Michigan System; University of Michigan; University of Michigan System; University of Michigan; University of Michigan System; University of Michigan
NR 19
TC 410
Z9 455
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 864
EP 866
DI 10.1038/353864a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200066
PM 1719426
DA 2026-03-10
ER

PT J
AU COMPANY, M
   ARENAS, J
   ABELSON, J
AF COMPANY, M
   ARENAS, J
   ABELSON, J
TI REQUIREMENT OF THE RNA HELICASE-LIKE PROTEIN PRP22 FOR RELEASE OF MESSENGER-RNA FROM SPLICEOSOMES
SO NATURE
LA English
DT Article
ID small nuclear ribonucleoprotein; nucleotide-sequence; ribosomal protein-s1; saccharomyces-cerevisiae; alpha-subunit; putative helicases; yeast; gene; cloning; atp
AB The product of the yeast PRP22 gene acts late in the splicing of yeast pre-messenger RNA, mediating the release of the spliced mRNA from the spliceosome. The predicted PRP22 protein sequence shares extensive homology with that of PRP2 and PRP16 proteins, which are also involved in nuclear pre-mRNA splicing. The homologous region contains sequence elements characteristic of several demonstrated or putative ATP-dependent RNA helicases. A putative RNA-binding motif originally identified in bacterial ribosomal protein S1 and Escherichia coli polynucleotide phosph orylase has also been found in PRP22.
RP COMPANY, M (corresponding author), CALTECH, DIV BIOL, PASADENA, CA 91125 USA.
NR 67
TC 315
Z9 344
U1 0
U2 9
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 487
EP 493
DI 10.1038/349487a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100055
PM 1992352
DA 2026-03-10
ER

PT J
AU HARTZELL, HC
   MERY, PF
   FISCHMEISTER, R
   SZABO, G
AF HARTZELL, HC
   MERY, PF
   FISCHMEISTER, R
   SZABO, G
TI SYMPATHETIC REGULATION OF CARDIAC CALCIUM CURRENT IS DUE EXCLUSIVELY TO CAMP-DEPENDENT PHOSPHORYLATION
SO NATURE
LA English
DT Article
ID g-protein; ion channels; single cells; acetylcholine; heart; stimulation; myocytes; modulation; kinase; analog
AB THE positive inotropic effect of the sympathetic nervous system on the heart is partly mediated by an increase in the voltage-gated Ca2+ current (I(Ca)). This increase is generally attributed to beta-adrenergic receptor-stimulated cyclic AMP-dependent phosphorylation of the Ca2+ channel 1,2. It has been suggested that cAMP-dependent phosphorylation cannot explain all the effects of beta-adrenergic agonists on I(Ca) and that a parallel membrane-delimited pathway involving the 'direct' action of the G protein G(s) also stimulates I(Ca) (refs 3-7). A precedent exists for such a membrane-delimited pathway in the activation of a K+ channel by acetylcholine in heart 1,8. A membrane-delimited pathway for stimulation of I(Ca) might be important in rapid beat-to-beat regulation of contraction by the sympathetic nervous system 9, because isoproterenol may produce a biphasic increase in I(Ca) with the rapid phase (tau = 150 ms) putatively mediated by the direct pathway and the slow phase (tau = 35 s) by cAMP-dependent phosphorylation. Here we report that in frog, rat, and guinea pig ventricular myocytes I(Ca) increases slowly and monophasically in response to isoproterenol. The increase is completely blocked by inhibitors of cAMP-dependent phosphorylation. Furthermore, the time course of the increase in I(Ca) closely parallels the increase in contractile force produced by sympathetic nerve stimulation. These data refute earlier suggestions that regulation of Ca2+ channels by the sympathetic nervous system involves or requires a direct G-protein pathway.
C1 UNIV PARIS 11, INSERM, U241, PHYSIOL CELLULAIRE CARDIAQUE LAB, F-91405 ORSAY, FRANCE.
   UNIV VIRGINIA, DEPT PHYSIOL, CHARLOTTESVILLE, VA 22908 USA.
C3 Institut National de la Sante et de la Recherche Medicale (Inserm); Universite Paris Saclay; University of Virginia
RP HARTZELL, HC (corresponding author), EMORY UNIV, SCH MED, DEPT ANAT & CELL BIOL, ATLANTA, GA 30322 USA.
NR 22
TC 217
Z9 226
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 573
EP 576
DI 10.1038/351573a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400061
PM 1710784
DA 2026-03-10
ER

PT J
AU GILLESGONZALEZ, MA
   DITTA, GS
   HELINSKI, DR
AF GILLESGONZALEZ, MA
   DITTA, GS
   HELINSKI, DR
TI A HEMOPROTEIN WITH KINASE-ACTIVITY ENCODED BY THE OXYGEN SENSOR OF RHIZOBIUM-MELILOTI
SO NATURE
LA English
DT Article
ID escherichia-coli; phosphorylation; expression; genes; nifa
AB THE expression of the nitrogen-fixation genes of Rhizobium meliloti is controlled by oxygen 1,2.  These genes are induced when the free oxygen concentration is reduced to microaerobic levels.  Two regulator proteins, FixL and FixJ, initiate the oxygen-response cascade, and the genes that encode them have been cloned 2,3.  The fixL product seems to be a transmembrane sensor that modulates the activity of the fixJ product, a cytoplasmic regulator 3.   FixL and FixJ are homologous to a family of bacterial two-component regulators 4, for which the mode of signal transduction is phosphorylation (reviewed in refs 5-9).  We report here the purification of both FixJ and a soluble truncated FixL (FixL*), overproduced from a single plasmid construct.  FixL* catalyses its own phosphorylation and the transfer of the gamma-phosphate of ATP to FixJ.  The resulting FixJ-phosphate linkage is sensitive to base, as are the aspartyl phosphates of homologous systems.  Visible spectra of purified FixL* show that it is an oxygen-binding haemoprotein.  We propose that FixL senses oxygen through its haem moiety and transduces this signal by controlling the phosphorylation of FixJ.
C1 UNIV CALIF SAN DIEGO,CTR MOLEC GENET,LA JOLLA,CA 92093.
C3 University of California System; University of California San Diego
RP GILLESGONZALEZ, MA (corresponding author), UNIV CALIF SAN DIEGO,DEPT BIOL,0634,LA JOLLA,CA 92093, USA.
NR 16
TC 451
Z9 488
U1 1
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 170
EP 172
DI 10.1038/350170a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500065
PM 1848683
DA 2026-03-10
ER

PT J
AU LOCKNER, DA
   BYERLEE, JD
   KUKSENKO, V
   PONOMAREV, A
   SIDORIN, A
AF LOCKNER, DA
   BYERLEE, JD
   KUKSENKO, V
   PONOMAREV, A
   SIDORIN, A
TI QUASI-STATIC FAULT GROWTH AND SHEAR FRACTURE ENERGY IN GRANITE
SO NATURE
LA English
DT Article
ID earthquake; model
AB The failure process in a brittle granite sample can be stabilized by controlling axial stress to maintain a constant rate of acoustic emission.  As a result, the post-failure stress curve can be followed quasi-statically, extending to hours the fault growth process which normally would occur violently in a fraction of a second.  Using a procedure originally developed to locate earthquakes, acoustic emission arrival-time data are inverted to obtain three-dimensional locations of microseisms.  These locations provide a detailed view of fracture nucleation and growth.
C1 AF IOFFE PHYSICOTECH INST,LENINGRAD 194021,USSR.
   ACAD SCI USSR,INST PHYS EARTH,MOSCOW 123810,USSR.
C3 Russian Academy of Sciences; St. Petersburg Scientific Centre of the Russian Academy of Sciences; Ioffe Physical Technical Institute; Russian Academy of Sciences; Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences
RP LOCKNER, DA (corresponding author), US GEOL SURVEY,345 MIDDLEFIELD RD,MENLO PK,CA 94025, USA.
NR 15
TC 845
Z9 959
U1 3
U2 129
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 39
EP 42
DI 10.1038/350039a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300055
DA 2026-03-10
ER

PT J
AU LIU, C
   MARTIN, CR
AF LIU, C
   MARTIN, CR
TI COMPOSITE MEMBRANES FROM PHOTOCHEMICAL-SYNTHESIS OF ULTRATHIN POLYMER-FILMS
SO NATURE
LA English
DT Article
ID technology; transport; sorption
AB THERE has recently been a resurgence of interest in synthetic membranes and membrane-based processes 1-12. This is motivated by a wide variety of technological applications, such as chemical separations 1-7, bioreactors and sensors 8,9, energy conversion 10,11 and drug-delivery systems 12. Many of these technologies require the ability to prepare extremely thin, defect-free synthetic (generally polymeric) films, which are supported on microporous supports to form composite membranes. Here we describe a method for producing composite membranes of this sort that incorporate high-quality polymer films less than 50-nm thick. The method involves interfacial photopolymerization of a thin polymer film on the surface of the microporous substrate. We have been able to use this technique to synthesize a variety of functionalized ultrathin films based on electroactive, photoactive and ion-exchange polymers. We demonstrate the method here with composite membranes that show exceptional gas-transport properties.
C1 COLORADO STATE UNIV,DEPT CHEM,FT COLLINS,CO 80523.
C3 Colorado State University System; Colorado State University Fort Collins
NR 17
TC 83
Z9 86
U1 0
U2 34
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 50
EP 52
DI 10.1038/352050a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800065
DA 2026-03-10
ER

PT J
AU GERSHON, D
AF GERSHON, D
TI NEUROSCIENCE AND ALL THAT JAZZ
SO NATURE
LA English
DT Article
NR 0
TC 0
Z9 0
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 90
EP 92
DI 
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900068
DA 2026-03-10
ER

PT J
AU LAM, KS
   SALMON, SE
   HERSH, EM
   HRUBY, VJ
   KAZMIERSKI, WM
   KNAPP, RJ
AF LAM, KS
   SALMON, SE
   HERSH, EM
   HRUBY, VJ
   KAZMIERSKI, WM
   KNAPP, RJ
TI A NEW TYPE OF SYNTHETIC PEPTIDE LIBRARY FOR IDENTIFYING LIGAND-BINDING ACTIVITY
SO NATURE
LA English
DT Article
ID phage
AB OUR aim was to improve techniques for drug development by facilitating the identification of small molecules that bind with high affinity to acceptor molecules (for example, cell-surface receptors, enzymes, antibodies) and so to mimic or block their interaction with the natural ligand 1,2. Previously such small molecules have been characterized individually on a serial basis. The systematic synthesis and screening of peptide libraries of defined structure represents a new approach. For relatively small libraries, predetermined sequence variations on solid-phase supports have been used 3,4, and large libraries have been produced using a bacteriophage vector into which random oligodeoxynucleotide sequences have been introduced 5-8, but these techniques have severe limitations. Here we investigate an alternative approach to synthesis and screening of peptide libraries. Our simple methodology greatly enhances the production and rapid evaluation of random libraries of millions of peptides so that acceptor-binding ligands of high affinity can be rapidly identified and sequenced, on the basis of a 'one-bead, one-peptide' approach.
C1 UNIV ARIZONA,FAC SCI,DEPT CHEM,TUCSON,AZ 85721.
   SELECTIDE CORP,TUCSON,AZ 85737.
   COLL MED TUCSON,DEPT INTERNAL MED,TUCSON,AZ 85724.
C3 University of Arizona; Sanofi-Aventis; Sanofi USA
RP LAM, KS (corresponding author), COLL MED TUCSON,ARIZONA CANC CTR,TUCSON,AZ 85724, USA.
NR 9
TC 1790
Z9 3021
U1 1
U2 229
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 82
EP 84
DI 10.1038/354082a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900064
PM 1944576
DA 2026-03-10
ER

PT J
AU GHIL, M
   VAUTARD, R
AF GHIL, M
   VAUTARD, R
TI INTERDECADAL OSCILLATIONS AND THE WARMING TREND IN GLOBAL TEMPERATURE TIME-SERIES
SO NATURE
LA English
DT Article
ID surface air-temperature; el-nino; climate; fluctuations; variability; dynamics
AB THE ability to distinguish a warming trend from natural variability is critical for an understanding of the climatic response to increasing greenhouse-gas concentrations.  Here we use singular spectrum analysis 1 to analyse the time series of global surface air temperatures for the past 135 years 2, allowing a secular warming trend and a small number of oscillatory modes to be separated from the noise.  The trend is flat until 1910, with an increase of 0.4-degrees-C since then.  The oscillations exhibit interdecadal periods of 21 and 16 years, and interannual periods of 6 and 5 years.  The interannual oscillations are probably related to global aspects of the El Nino-Southern Oscillation (ENSO) phenomenon 3.  The interdecadal oscillations could be associated with changes in the extratropical ocean circulation 4.  The oscillatory components have combined (peak-to-peak) amplitudes of > 0.2-degrees-C, and therefore limit our ability to predict whether the inferred secular warming trend of 0.005-degrees-C yr-1 will continue.  This could postpone incontrovertible detection of the greenhouse warming signal for one or two decades.
C1 UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024.
   ECOLE NORM SUPER,CNRS,METEOROL DYNAM LAB,F-75231 PARIS 05,FRANCE.
C3 University of California System; University of California Los Angeles; Sorbonne Universite; Centre National de la Recherche Scientifique (CNRS); Universite PSL; Ecole Normale Superieure (ENS); Institut Polytechnique de Paris; Ecole Polytechnique
RP GHIL, M (corresponding author), UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,CTR CLIMATE DYNAM,LOS ANGELES,CA 90024, USA.
NR 29
TC 422
Z9 467
U1 0
U2 41
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 324
EP 327
DI 10.1038/350324a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800086
DA 2026-03-10
ER

PT J
AU WILKINSON, PN
   TZIOUMIS, AK
   BENSON, JM
   WALKER, RC
   SIMON, RS
   KAHN, FD
AF WILKINSON, PN
   TZIOUMIS, AK
   BENSON, JM
   WALKER, RC
   SIMON, RS
   KAHN, FD
TI A DISRUPTED RADIO JET INSIDE THE HOST GALAXY OF THE QUASAR 3C48
SO NATURE
LA English
DT Article
ID spectroscopy; nebulosity; spectrum; 3c-48; fuzz; qsos; flow
AB THE nearby quasar 3C48 was the first to be optically identified 1, and its redshift, z = 0.368 (ref. 2), was the second, after that of 3C273 3, to be determined. Despite this pedigree, its detailed radio structure has remained obscure because its angular size, approximately 1 arcsec, is so small. We present here a new radio image, with resolution < 10 mas, made by very-long-baseline interferometry using an array of 17 telescopes. We find a highly disrupted radio jet quite different from those found in standard high-luminosity radio sources. The jet lies well within the body of the gas-rich host galaxy of the quasar, and we believe that its irregular shape is due to collision with a dense clump of gas in the interstellar medium of the host galaxy, rather than to any irregularity or precession of the central engine that produces the jet.
C1 NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801.
   USN,RES LAB,EO HULBURT CTR SPACE RES,WASHINGTON,DC 20375.
   UNIV MANCHESTER,DEPT ASTRON,MANCHESTER M13 9PL,LANCS,ENGLAND.
C3 National Radio Astronomy Observatory (NRAO); United States Department of Defense; United States Navy; United States Naval Research Laboratory; NRL Chesapeake; University of Manchester
RP WILKINSON, PN (corresponding author), UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,JORDELL BANK,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND.
NR 29
TC 61
Z9 64
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 313
EP 315
DI 10.1038/352313a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900062
DA 2026-03-10
ER

PT J
AU WANK, R
   THOMSSEN, C
AF WANK, R
   THOMSSEN, C
TI HIGH-RISK OF SQUAMOUS-CELL CARCINOMA OF THE CERVIX FOR WOMEN WITH HLA-DQW3
SO NATURE
LA English
DT Article
ID herpes-simplex virus; class-ii molecules; hla-dr antigen; ankylosing-spondylitis; association; specificity; h-2-complex; complex; locus
AB MANY immune responses are controlled by genes of the major histocompatibility complex (MHC) 1. In man these include the loci encoding the HLA-A, -B, -C, -DR, -DQ and -DP antigens, and many diseases have been linked with these 2-5. But attempts to identify HLA genes in man that might explain why an immune response against malignant tumours should be ineffective have so far been disappointing, apart from the association reported between the HLA-DRI antigen and a susceptibility to a rare carcinoma of the thyroid gland 6. Here we describe another strong connection between a common malignant tumour and an HLA antigen, namely between HLA-DQw3 and squamous cell carcinoma of the cervix: from the 1988 United States tumour registry, 1 in every 63 newborn girls will develop this invasive cancer 7. We found that 88% of 66 patients had the leukocyte antigen HLA-DQw3 when it would normally be expected in only 50% of individuals. In animals the immune system and the MHC act in defence against virally induced tumours, but until now there has been no evidence that they do so in humans 8: as squamous cell carcinoma is probably virally induced, our discovery of its association with an HLA antigen will be important to the understanding of the immunogenetic basis of a susceptibility to this tumour.
C1 TECH UNIV MUNICH, DEPT OBSTET & GYNAECOL, W-8000 MUNICH 80, GERMANY.
C3 Technical University of Munich
RP WANK, R (corresponding author), UNIV MUNICH, DEPT IMMUNOL, GOETHESTR 31, W-8000 MUNICH 2, GERMANY.
NR 33
TC 244
Z9 259
U1 0
U2 3
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 723
EP 725
DI 10.1038/352723a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400061
PM 1876187
DA 2026-03-10
ER

PT J
AU KAWABATA, S
   HIGGINS, GA
   GORDON, JW
AF KAWABATA, S
   HIGGINS, GA
   GORDON, JW
TI RETRACTED: AMYLOID PLAQUES, NEUROFIBRILLARY TANGLES AND NEURONAL LOSS IN BRAINS OF TRANSGENIC MICE OVEREXPRESSING A C-TERMINAL FRAGMENT OF HUMAN AMYLOID PRECURSOR PROTEIN (RETRACTED ARTICLE. SEE VOL 356, PG 265, 1992)
SO NATURE
LA English
DT Article; Retracted Publication
ID alzheimers-disease; differential regulation; gene-expression; downs-syndrome; mouse embryos; thy-1 gene; dna; injection; receptor
AB ALZHEIMER's disease (AD) affects more than 30% of people over 80 years of age 1,2. The aetiology and pathogenesis of this progressive dementia is poorly understood, but symptomatic disease is associated histopathologically with amyloid plaques, neurofibrillary tangles and neuronal loss primarily in the temporal lobe and neocortex of the brain. The core of the extracellular plaque is a derivative of the amyloid precursor protein (App) 3, referred to as beta/A4 (refs 4-6), and contains the amino-acid residues 29-42 that are normally embedded in the membrane-spanning region of the precursor 3. The cellular source of APP and the relationship of its deposition to the neuropathology of AD is unknown. To investigate the relationship between APP overexpression and amyloidogenesis, we have developed a vector to drive expression specifically in neurons of a C-terminal fragment of APP that contains the beta/A4 region, and have used a transgenic mouse system 7,8 to insert and express this construct. We report here that overexpression of this APP transgene in neurons is sufficient to produce extracellular dense-core amyloid plaques, neurofibrillary tangles and neuronal degeneration similar to that in the AD brain.
C1 MT SINAI MED CTR, DEPT GERIATR & ADULT DEV, 2056 ANNENBERG, NEW YORK, NY 10029 USA.
   MT SINAI MED CTR, DEPT OBSTET GYNECOL & REPROD SCI, NEW YORK, NY 10029 USA.
   YAMANOUCHI PHARMACEUT CO LTD, TOKYO 103, JAPAN.
   NIA, GERONTOL RES CTR, BALTIMORE, MD 21224 USA.
C3 Icahn School of Medicine at Mount Sinai; Icahn School of Medicine at Mount Sinai; Astellas Pharmaceuticals; National Institutes of Health (NIH) - USA; NIH National Institute on Aging (NIA)
RP GORDON, JW (corresponding author), MT SINAI MED CTR, DEPT GERIATR & ADULT DEV, 2056 ANNENBERG, NEW YORK, NY 10029 USA.
NR 30
TC 89
Z9 122
U1 0
U2 18
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 476
EP 478
DI 10.1038/354476a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800059
PM 1793460
DA 2026-03-10
ER

PT J
AU HAHM, JO
   LANGDON, RB
   SUR, M
AF HAHM, JO
   LANGDON, RB
   SUR, M
TI DISRUPTION OF RETINOGENICULATE AFFERENT SEGREGATION BY ANTAGONISTS TO NMDA RECEPTORS
SO NATURE
LA English
DT Article
ID lateral geniculate-nucleus; visual-cortex; cat; infusion; ferret; tetrodotoxin; projection; potentials; cells; field
AB AFFERENT activity has an important role in the formation of connections in the developing mammalian visual system 1,2.  But the extent to which the activity of target neurons shapes patterns of afferent termination and synaptic contact is not known.  In the ferret's visual pathway, retinal ganglion cell axons from each eye segregate early in development into eye-specific laminae in the lateral geniculate nucleus (LGN)3.   The dorsal laminae (termed laminae A and A1) then segregate further into inner and outer sublaminae that retain input from on-centre and off-centre retinal axons, respectively 4,5.  Thus, individual retinogeniculate axons form terminal arbors within laminae A and A1 that are restricted to one inner or outer sublamina 6.  We report here that blockade of N-methyl-D-aspartate  (NMDA) receptors on LGN cells with specific antagonists during the period of sublamina formation prevents retinal afferents from segregating into 'On' and 'Off' sublaminae.  Retinogeniculate axons have arbors that are not restricted appropriately, or are restricted in size but inappropriately positioned within the eye-specific laminae.  NMDA receptor antagonists may specifically disrupt a mechanism by which LGN neurons detect correlated afferent and target activity 7, and have been shown to reduce retinogeniculate transmission more generally 8-10, causing LGN cells to have markedly reduced levels of activity.  These results therefore indicate that the activity of postsynaptic cells can significantly influence the patterning of inputs and the structure of presynaptic afferents during development.
C1 MIT,DEPT BRAIN & COGNIT SCI,CAMBRIDGE,MA 02139.
C3 Massachusetts Institute of Technology (MIT)
NR 24
TC 232
Z9 243
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 568
EP 570
DI 10.1038/351568a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400059
PM 1675433
DA 2026-03-10
ER

PT J
AU BENFIELD, RE
   CRAGG, RH
   JONES, RG
   SWAIN, AC
AF BENFIELD, RE
   CRAGG, RH
   JONES, RG
   SWAIN, AC
TI AIR-STABLE ALKALI-METAL COLLOIDS AND THE BLUE COLOR IN WURTZ SYNTHESES
SO NATURE
LA English
DT Article
ID electron spin-resonance; small particles; sodium
AB POLYSILANES are used as resists in microlithography and as precursors for silicon carbide ceramics 1-3.  We have been investigating the formation of polysilanes by the reductive dechlorination polymerization of dichloro-organosilanes with sodium4 - a modification of the well-known Wurtz reaction, in which organic halides are reductively coupled using sodium to form carbon-carbon single bonds.  In all such reactions, after a period of time a blue precipitate is formed, but no characterization of this solid has so far been reported.  It has been suggested (without spectroscopic evidence) that the colour in the polysilane synthesis is due to defects in sodium chloride 1, sodium colour centres in sodium chloride 3,5, reactive polysilane chain-ends 3 or a stabilized organic radical 6.  The first of these suggestions has been tacitly accepted despite the fact that the most common defects in sodium chloride are F centres (anion vacancies with trapped electrons from excess sodium atoms) which give the salt a yellow colour 7,8.  Here we present spectroscopic results suggesting that the blue colour is due to colloidal alkali-metal particles formed during the reaction.  These particles are contained in a matrix composed of an intimate mixture of polymer and alkali-metal halide, and are remarkably stable in air.  It is most unusual for colloidal metal particles to be formed under such mild conditions.
C1 UNIV KENT,CTR MAT RES,CHEM LAB,CANTERBURY CT2 7NH,KENT,ENGLAND.
C3 University of Kent
NR 26
TC 26
Z9 26
U1 2
U2 19
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 340
EP 341
DI 10.1038/353340a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400055
DA 2026-03-10
ER

PT J
AU FLANAGAN, WM
   CORTHESY, B
   BRAM, RJ
   CRABTREE, GR
AF FLANAGAN, WM
   CORTHESY, B
   BRAM, RJ
   CRABTREE, GR
TI NUCLEAR-ASSOCIATION OF A T-CELL TRANSCRIPTION FACTOR BLOCKED BY FK-506 AND CYCLOSPORINE-A
SO NATURE
LA English
DT Article
ID cytosolic binding-protein; peptidyl-prolyl isomerase; cis-trans isomerase; immunosuppressant fk506; fk506-binding protein; gel-electrophoresis; neurospora-crassa; macrolides fk-506; cyclophilin; activation
AB CYCLOSPORIN A and FK506 inhibit T- and B-cell activation and other processes essential to an effective immune response 1-3.  In T lymphocytes these drugs disrupt an unknown step in the transmission of signals from the T-cell antigen receptor to cytokine genes that coordinate the immune response 4-6.  The putative intracellular receptors for FK506 and cyclosporin are cis-trans prolyl isomerases 7-11.  Binding of the drug inhibits isomerase activity 8,10,11, but studies with other prolyl isomerase inhibitors 12 and analysis of cyclosporin-resistant mutants in yeast suggest that the effects of the drug result from the formation of an inhibitory complex between the drug and isomerase 13,14, and not from inhibition of isomerase activity.  A transcription factor, NF-AT, which is essential for early T-cell gene activation, seems to be a specific target of cyclosporin A and FK506 action because transcription directed by this protein is blocked in T cells treated with these drugs, with little or no effect on other transcription factors such as AP-1 and NF-kappa-B (refs 15-17).  Here we demonstrate that NF-AT is formed when a signal from the antigen receptor induces a pre-existing cytoplasmic subunit to translocate to the nucleus and combine with a newly synthesized nuclear subunit of NF-AT.  FK506 and cyclosporin A block translocation of the cytoplasmic component without affecting synthesis of the nuclear subunit.
RP FLANAGAN, WM (corresponding author), STANFORD UNIV,MED CTR,SCH MED,HOWARD HUGHES MED INST,BECKMAN CTR MOLEC & GENET MED,STANFORD,CA 94305, USA.
NR 34
TC 1061
Z9 1154
U1 0
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 803
EP 807
DI 10.1038/352803a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400060
PM 1715516
DA 2026-03-10
ER

PT J
AU BARLOW, DP
   STOGER, R
   HERRMANN, BG
   SAITO, K
   SCHWEIFER, N
AF BARLOW, DP
   STOGER, R
   HERRMANN, BG
   SAITO, K
   SCHWEIFER, N
TI THE MOUSE INSULIN-LIKE GROWTH-FACTOR TYPE-2 RECEPTOR IS IMPRINTED AND CLOSELY LINKED TO THE TME LOCUS
SO NATURE
LA English
DT Article
ID t-complex; chromosome-17; haplotype; gene
AB T-ASSOCIATED maternal effect (Tme) is the only known maternal-effect mutation in the mouse1,2.  The defect is nuclear-encoded3 and embryos that inherit a deletion of the Tme locus from their mother die at day 15 of gestation4.  There are many genomically imprinted regions known in the mouse genome5,6, but so far no imprinted genes have been cloned. The Tme locus is absent in two chromosome-17 deletion mutants, T(hp) and the t(Lub2), and its position has been localized using these deletions to a 1-cM region7-10.  We report here that the genes for insulin-like growth factor type-2 receptor (Igf2r) and mitochondrial superoxide dismutase-2 (Sod-2) are absent from both deletions.  Probes for these genes and for plasminogen (Plg) and T-complex peptide 1 (Tcp-1) were used in pulsed-field gel mapping to show that Tme must lie within a region of 800-1,100 kb.  We also demonstrate that embryos express Igf2r only from the maternal chromosome, and that Tcp-1, Plg and Sod-2 are expressed from both chromosomes.  Therefore Igf2r is imprinted and closely linked or identical to Tme.
C1 MAX PLANCK INST ENTWICKLUNGSBIOL,W-7400 TUBINGEN,GERMANY.
   VANDERBILT UNIV,NASHVILLE,TN 37232.
C3 Max Planck Society; Vanderbilt University
RP BARLOW, DP (corresponding author), RES INST MOLEC PATHOL,DR BOHR GASSE 7,A-1030 VIENNA,AUSTRIA.
NR 25
TC 781
Z9 889
U1 0
U2 64
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 84
EP 87
DI 10.1038/349084a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100059
PM 1845916
DA 2026-03-10
ER

PT J
AU BOUTRON, CF
   GORLACH, U
   CANDELONE, JP
   BOLSHOV, MA
   DELMAS, RJ
AF BOUTRON, CF
   GORLACH, U
   CANDELONE, JP
   BOLSHOV, MA
   DELMAS, RJ
TI DECREASE IN ANTHROPOGENIC LEAD, CADMIUM AND ZINC IN GREENLAND SNOWS SINCE THE LATE 1960S
SO NATURE
LA English
DT Article
ID atmospheric trace-metals; temporal variability; ice; elements; water; soils
AB MORE than twenty years ago, Patterson and co-workers 1 showed that evidence of lead concentrations in Greenland ice and snow had increased about 200-fold since ancient times. From their results, they concluded that more than 99% of this highly toxic metal in the global troposphere of the Northern Hemisphere originated from human activities in the mid 1960s-mainly from the use of alkyl-leaded petrol. At least in part because of this evidence, the United States and other countries limited the use of lead additives in petrol from about 1970. Here we report that, as a result of these policy initiatives, lead concentrations in Greenland snow have decreased by a factor of 7.5 over the past twenty years. We also show that over the same time period, cadmium and zinc concentrations have decreased by a factor of 2.5.
C1 ACAD SCI USSR, INST SPECT, TROITSK 142092, USSR.
C3 Russian Academy of Sciences; Institute of Spectroscopy
RP BOUTRON, CF (corresponding author), CNRS, GLACIOL & GEOPHYS ENVIRONM LAB, 54 RUE MOLIERE, DOMAINE UNIV, BP 96, F-38402 ST MARTIN DHERES, FRANCE.
NR 27
TC 252
Z9 282
U1 0
U2 50
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 153
EP 156
DI 10.1038/353153a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100049
DA 2026-03-10
ER

PT J
AU ROULD, MA
   PERONA, JJ
   STEITZ, TA
AF ROULD, MA
   PERONA, JJ
   STEITZ, TA
TI STRUCTURAL BASIS OF ANTICODON LOOP RECOGNITION BY GLUTAMINYL-TRANSFER RNA-SYNTHETASE
SO NATURE
LA English
DT Article
ID phenylalanine transfer-rna; escherichia-coli; crystal-structure; 2.8-a resolution; translation; refinement; atp
AB The refined crystal structure of Escherichia coli glutaminyl transfer RNA synthetase complexed with transfer RNA(Gln) and ATP reveals that the structure of the anticodon loop of the enzyme-bound tRNA(Gln) differs extensively from that of the known crystal structures of uncomplexed tRNA molecules. The anticodon stem is extended by two non-Watson-Crick base pairs, leaving the three anticodon bases unpaired and splayed out to bind snugly into three separate complementary pockets in the protein. These interactions suggest that the entire anticodon loop provides essential sites for glutaminyl tRNA synthetase discrimination among tRNA molecules.
C1 YALE UNIV, DEPT CHEM, NEW HAVEN, CT 06511 USA.
   YALE UNIV, HOWARD HUGHES MED INST, NEW HAVEN, CT 06511 USA.
C3 Yale University; Howard Hughes Medical Institute; Yale University
RP ROULD, MA (corresponding author), YALE UNIV, DEPT MOLEC BIOPHYS & BIOCHEM, POB 6666, NEW HAVEN, CT 06511 USA.
NR 26
TC 363
Z9 388
U1 0
U2 17
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 213
EP 218
DI 10.1038/352213a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500054
PM 1857417
DA 2026-03-10
ER

PT J
AU NAVON, O
AF NAVON, O
TI HIGH INTERNAL-PRESSURES IN DIAMOND FLUID INCLUSIONS DETERMINED BY INFRARED-ABSORPTION
SO NATURE
LA English
DT Article
ID solid co2; spectroscopy; quartz; temperatures; compression; raman; water
AB FLUID inclusions in mantle-derived minerals provide a rare opportunity to study deep-seated mantle fluids. Among mantle minerals, only diamond possesses sufficient strength to encapsulate and transport to the surface fluids that were trapped at depths below 100 km (ref. 1). Previous studies of the bulk composition 2 and internal morphology 3 of micro-inclusions in cubic and coated diamonds suggested that they contain fluids, but their depth of origin could not be determined. Here I report infrared spectroscopic evidence for residual internal pressures of 1.5-2.1 GPa within these micro-inclusions, higher than any reported previously for fluid inclusions. Extrapolation to mantle temperatures indicates fluid pressures of 4-7 GPa, comparable to those estimated on the basis of mineral equilibria between crystalline inclusions in diamond 4. These pressures fall within the diamond stability field in the upper mantle, suggesting that the deep-seated fluids, rich in H2O, CO2, SiO2, and K2O, are probably the mother solutions from which cubic, and possibly eclogitic diamonds grow.
RP NAVON, O (corresponding author), HEBREW UNIV JERUSALEM,INST EARTH SCI,IL-91904 JERUSALEM,ISRAEL.
NR 26
TC 138
Z9 142
U1 1
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 746
EP 748
DI 10.1038/353746a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600065
DA 2026-03-10
ER

PT J
AU RUSSELL, DM
   DEMBIC, Z
   MORAHAN, G
   MILLER, JFAP
   BURKI, K
   NEMAZEE, D
AF RUSSELL, DM
   DEMBIC, Z
   MORAHAN, G
   MILLER, JFAP
   BURKI, K
   NEMAZEE, D
TI PERIPHERAL DELETION OF SELF-REACTIVE B-CELLS
SO NATURE
LA English
DT Article
ID immunoglobulin-m; transgenic mice; clonal deletion; lymphocytes-b; t-cell; tolerance; susceptibility; suppression; expression; antigens
AB B LYMPHOCYTES are key participants in the immune response because of their specificity, their ability to take up and present antigens to T cells, and their capacity to differentiate into antibody-secreting cells. To limit reactivity to self antigens, autospecific B cells can be functionally inactivated or deleted 1-4. Developing B cells that react with membrane antigens expressed in the bone, marrow are deleted from the peripheral lymphocyte pool 4-6. It is important to ascertain the fate of B cells that recognize membrane autoantigens expressed exclusively on peripheral tissues because B cells in the peripheral lymphoid organs are phenotypically and functionally distinct from bone-marrow B cells 7-9. Here we show that in immunoglobulin-transgenic mice, B cells specific for major histocompatibility complex class I antigen can be deleted if they encounter membrane-bound antigen at a post-bone-marrow stage of development. This deletion may be necessary to prevent organ-specific autoimmunity.
C1 NATL JEWISH CTR IMMUNOL & RESP MED,DEPT PEDIAT,DIV BASIC SCI,1400 JACKSON ST,DENVER,CO 80206.
   HOFFMANN LA ROCHE AG,DEPT MOLEC BIOL,CH-4005 BASEL,SWITZERLAND.
   ROYAL MELBOURNE HOSP,WALTER & ELIZA HALL INST MED RES,PARKVILLE,VIC 3050,AUSTRALIA.
   ROYAL MELBOURNE HOSP,PARKVILLE,VIC 3050,AUSTRALIA.
   SANDOZ LTD,DEPT BIOTECHNOL,CH-4002 BASEL,SWITZERLAND.
   UNIV COLORADO,HLTH SCI CTR,DEPT MICROBIOL & IMMUNOL,DENVER,CO 80262.
C3 National Jewish Health; Roche Holding; Walter & Eliza Hall Institute; Melbourne Health; Royal Melbourne Hospital; Melbourne Health; Royal Melbourne Hospital; Novartis; Sandoz; University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus
FU NIGMS NIH HHS [R01 GM044809] Funding Source: Medline
NR 29
TC 331
Z9 372
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 308
EP 311
DI 10.1038/354308a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400048
PM 1956380
DA 2026-03-10
ER

PT J
AU ITO, T
   TAKAGI, H
   ISHIBASHI, S
   IDO, T
   UCHIDA, S
AF ITO, T
   TAKAGI, H
   ISHIBASHI, S
   IDO, T
   UCHIDA, S
TI NORMAL-STATE CONDUCTIVITY BETWEEN CUO2 PLANES IN COPPER-OXIDE SUPERCONDUCTORS
SO NATURE
LA English
DT Article
ID single-crystal; resistivity; temperature
AB THE high-transition-temperature (high-T(c)) copper oxide superconductors are highly anisotropic in their electrical properties; this is one of the key concerns for applications of these materials, and may also provide a clue to the mechanism of the superconductivity.  Although the resistivity in the CuO2 planes, rho-ab, shows a metallic temperature dependence, the resistivity parallel to the c axis (rho-c) has been reported to be both non-metallic 1,2 and metallic 3,4.  Here we present systematic data for rho-c in a number of high-T(c) materials, obtained from well characterized single crystals.  Both the magnitude and the temperature dependence of rho-c are strongly dependent on crystal structure, and on the concentration of charge carriers.  We find that rho-c is non-metallic (d-rho-c/dT < 0) in most superconducting compounds, suggesting an unconventional conduction mechanism.  Fully oxygenated YBa2Cu3O approximately 7 (with T(c) almost-equal-to 90 K) is the only exception, with a relatively small rho-c and positive d-rho-c/dT that may arise from the crystal structure specific to this material.
RP ITO, T (corresponding author), UNIV TOKYO,DEPT APPL PHYS,BUNKYO KU,TOKYO 113,JAPAN.
NR 15
TC 232
Z9 241
U1 1
U2 25
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 596
EP 598
DI 10.1038/350596a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200054
DA 2026-03-10
ER

PT J
AU GASKELL, PH
   ECKERSLEY, MC
   BARNES, AC
   CHIEUX, P
AF GASKELL, PH
   ECKERSLEY, MC
   BARNES, AC
   CHIEUX, P
TI MEDIUM-RANGE ORDER IN THE CATION DISTRIBUTION OF A CALCIUM SILICATE GLASS
SO NATURE
LA English
DT Article
AB Silicate glasses have conventionally been regarded as silicate frameworks in which cations are distributed at random.  Neutron scattering from isotopically substituted samples allows correlations between cations to be investigated beyond the nearest-neighbour coordination shell, and shows that a degree of ordering persists over distances approaching 1 nm.  The structural picture that emerges has elements of long-range randomness coexisting with both short- and medium-range order.
C1 INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE.
C3 Institut Laue-Langevin (ILL)
RP GASKELL, PH (corresponding author), UNIV CAMBRIDGE,CAVENDISH LAB,MADINGLEY RD,CAMBRIDGE CB3 0HE,ENGLAND.
NR 11
TC 248
Z9 256
U1 0
U2 31
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 675
EP 677
DI 10.1038/350675a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000049
DA 2026-03-10
ER

PT J
AU WINSTON, D
   ARORA, M
   MASELKO, J
   GASPAR, V
   SHOWALTER, K
AF WINSTON, D
   ARORA, M
   MASELKO, J
   GASPAR, V
   SHOWALTER, K
TI CROSS-MEMBRANE COUPLING OF CHEMICAL SPATIOTEMPORAL PATTERNS
SO NATURE
LA English
DT Article
ID belousov-zhabotinskii reaction; oscillators; system; phase; waves
AB CHEMICAL systems may communicate by exchange of common species through mass transport, and such coupling may give rise to dynamical complexity beyond that possible in the independent systems 1-5.  We report here on dynamical behaviour arising from the diffusive coupling of chemical spatiotemporal patterns across a membrane.  Chemical waves appear on Nafion membranes that are loaded with ferroin catalyst and bathed in a mixture of the reagents of the Belousv-Zhabotinsky oscillatory reaction.  The waves on each side of the membrane couple by diffusive transport through the membrane.  The coupling initially gives rise to the spontaneous appearance of spiral waves, and subsequent behaviour reveals several distinct phases of evolution, ultimately leading to complete spatiotemporal entrainment.
C1 W VIRGINIA UNIV,DEPT CHEM,MORGANTOWN,WV 26506.
C3 West Virginia University
NR 16
TC 98
Z9 100
U1 0
U2 18
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 132
EP 135
DI 10.1038/351132a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500044
DA 2026-03-10
ER

PT J
AU ROBLES, L
   RUGGERO, MA
   RICH, NC
AF ROBLES, L
   RUGGERO, MA
   RICH, NC
TI 2-TONE DISTORTION IN THE BASILAR-MEMBRANE OF THE COCHLEA
SO NATURE
LA English
DT Article
ID mechanics; nonlinearity; responses; 2f1-f2; motion; tones; nerve
AB WHEN humans listen to pairs of thnes they hear additional tones, or distortion products, that are not present in the stimulus 1.  Two-tone distortion products are also known as combination tones, because their pitches match combinations of the primary frequencies (f1 and f2,f2 > f1), such as f2 - f1, (n+1)f1 - nf2 and (n + 1)f2 - nf1 (n = 1,2,3...) (refs 2-4).  Physiological correlates of the perceived distortion products exist in responses of auditory-nerve fibres 5-8 and inner hair cells 9 and in otoacoustic emissions (sounds generated by the cochlea, recordable at the ear canal) 7, 10-12.  Because the middle ear responds linearly to sound 13, 14 and neural responses to distortion products can be abolished by damage to hair cells at cochlear sites preferentially tuned to the frequencies of the primary tones 8, it was hypothesized that distortion products are generated at these sites and propagate mechanically along the basilar membrane to the location tuned to the distortion-product frequency 7,8.  But until now, efforts to confirm this hypothesis have failed 15,16.  Here we report the use of a new laser-velocimetry technique 17 to demonstrate two-tone distortion in basilar-membrane motion at low and moderate stimulus intensities.
C1 UNIV CHILE,FAC MED,DEPT FISIOL & BIOFIS,SANTIAGO,CHILE.
C3 Universidad de Chile
RP ROBLES, L (corresponding author), UNIV MINNESOTA,DEPT OTOLARYNGOL,2630 UNIV AVE SE,MINNEAPOLIS,MN 55414, USA.
FU NIDCD NIH HHS [R01 DC000419] Funding Source: Medline
NR 24
TC 143
Z9 160
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 413
EP 414
DI 10.1038/349413a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400050
PM 1992342
DA 2026-03-10
ER

PT J
AU TRUCHET, G
   ROCHE, P
   LEROUGE, P
   VASSE, J
   CAMUT, S
   DEBILLY, F
   PROME, JC
   DENARIE, J
AF TRUCHET, G
   ROCHE, P
   LEROUGE, P
   VASSE, J
   CAMUT, S
   DEBILLY, F
   PROME, JC
   DENARIE, J
TI SULFATED LIPO-OLIGOSACCHARIDE SIGNALS OF RHIZOBIUM-MELILOTI ELICIT ROOT NODULE ORGANOGENESIS IN ALFALFA
SO NATURE
LA English
DT Article
ID host-specificity; nodulation genes; mutants; plant; leguminosarum; symbiosis; products; common; nodh
AB RHIZOBIUM meliloti is a symbiotic bacterium that elicits the morphogenesis of nitrogen-fixing nodules, specific organs on the roots of alfalfa (Medicago sativa) 1.  In R. meliloti a series of nodulation (nod) genes have been identified which are involved in root-hair curling and infection and in nodule formation 1.  The nodABC genes, common to all Rhizobium sp., and the host-range nodH and nodPQ genes are involved in the production of an excreted root-hair deforming factor, NodRm-1, which is a sulphated and acylated glucosamine oligosaccharide 2-7.  Here we report that purified NodRm-1 and a related compound, Ac-NodRm-1, at concentrations in the micromolar-nanomolar range, elicit cortical cell divisions and the formation of genuine nodules on aseptically grown seedlings of alfalfa.  Chemical modifications of NodRm-1, such as the removal of the sulphate group, reduction of the terminal sugar or hydrogenation of the acyl chain result in a strong decrease in the morphogenic activity.  A highly specific prokaryotic lipo-oligosaccharide signal is thus able to trigger a genuine organogenesis in a higher plant.
C1 CNRS,CTR RECH BIOCHIM & GENET CELLULAIRES,F-31062 TOULOUSE,FRANCE.
C3 Centre National de la Recherche Scientifique (CNRS)
RP TRUCHET, G (corresponding author), INRA,CNRS,BIOL MOLEC RELAT PLANTES MICROORGANISMES,BP 27,F-31326 CASTANET TOLOSAN,FRANCE.
NR 30
TC 462
Z9 497
U1 3
U2 44
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 670
EP 673
DI 10.1038/351670a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200073
DA 2026-03-10
ER

PT J
AU VOIGHT, B
   CORNELIUS, RR
AF VOIGHT, B
   CORNELIUS, RR
TI PROSPECTS FOR ERUPTION PREDICTION IN NEAR REAL-TIME
SO NATURE
LA English
DT Article
ID mount st-helens
AB THE 'materials science' method for eruption prediction 1-3 arises from the application of a general law governing the failure of materials:  OMEGA-alpha OMEGA - A = 0, where A and alpha are empirical constants, and OMEGA is an observable quantity such as ground deformation, seismicity or gas emission.  This law leads to the idea of the 'inverse-rate' plot, in which the time of failure can be estimated by extrapolation of the curve of OMEGA-1 versus time to a pre-determined intercept.  Here we suggest that this method can be combined with real-time seismic amplitude monitoring to provide a tool for near-real-time eruption prediction, and we demonstrate how it might have been used to predict two dome-growth episodes at Mount St Helens volcano in 1985 and 1986, and two explosive eruptions at Redoubt volcano in 1989-90.
C1 US GEOL SURVEY,MENLO PK,CA 94025.
C3 United States Department of the Interior; United States Geological Survey
RP VOIGHT, B (corresponding author), PENN STATE UNIV,COLL EARTH & MINERAL SCI,UNIVERSITY PK,PA 16802, USA.
NR 20
TC 106
Z9 114
U1 0
U2 8
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 695
EP 698
DI 10.1038/350695a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000056
DA 2026-03-10
ER

PT J
AU WATERS, MG
   SERAFINI, T
   ROTHMAN, JE
AF WATERS, MG
   SERAFINI, T
   ROTHMAN, JE
TI COATOMER - A CYTOSOLIC PROTEIN COMPLEX CONTAINING SUBUNITS OF NON-CLATHRIN-COATED GOLGI TRANSPORT VESICLES
SO NATURE
LA English
DT Article
ID brefeldin-a; endoplasmic-reticulum
AB GOLGI-derived coated vesicles contain a set of coat proteins of relative molecular mass 160,000 (M(r) 160K; alpha-COP), 110K (beta-COP), 98K (gamma-COP) and 61K (delta-COP), and several smaller subunits 1. We have now identified and purified a cytosolic complex containing the same four coat proteins as those of Golgi transport vesicles. We term this complex the Golgi coat promoter or 'coatomer'. The customer also contains polypeptides of M(r) 36K, 35K and 20K. It represents about 0.2% of soluble cytosolic protein. Gel filtration of unfractionated cytosol indicates that beta-COP resides exclusively in the coatomer complex. The complex seems to be a likely candidate for the unassembled precursor of Golgi coated vesicles, and its purification should help investigations of the role of coat proteins in membrane budding, for which it is necessary to use a refined cell-free system.
RP WATERS, MG (corresponding author), PRINCETON UNIV, DEPT MOLEC BIOL, PRINCETON, NJ 08544 USA.
NR 15
TC 454
Z9 527
U1 1
U2 33
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 248
EP 251
DI 10.1038/349248a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900059
PM 1898986
DA 2026-03-10
ER

PT J
AU THOMSON, BJ
   EFSTATHIOU, S
   HONESS, RW
AF THOMSON, BJ
   EFSTATHIOU, S
   HONESS, RW
TI ACQUISITION OF THE HUMAN ADENOASSOCIATED VIRUS TYPE-2 REP GENE BY HUMAN HERPESVIRUS TYPE-6
SO NATURE
LA English
DT Article
ID inhibits cellular-transformation; human parvovirus b19; nucleotide-sequence; genome organization; expression; cells; dna; infection; binding; tropism
AB HUMAN herpesvirus type-6 (HHV-6) is a recently isolated herpesvirus which is highly prevalent in adult populations around the world 1-3.  HHV-6 was first isolated from the peripheral blood of six individuals with lymphoproliferative disorders, two of whom were also infected with human immunodeficiency virus 1.  HHV-6, in common with other herpesviruses, transactivates the HIV long terminal repeat linked to reporter genes 4,5 and has in addition been shown to accelerate HIV gene expression and CD4 cell death in cultures co-infected with both viruses 6.  The virus is tropic for CD4+ lymphocytes 7,8 and persists in the peripheral blood of most seropositive individuals 9.  We have now identified a gene in HHV-6 encoding a 490-amino-acid polypeptide homologous to the human adeno-associated virus type-2 (AAV-2) rep gene 10.  This gene has an essential role in AAV-2 DNA replication 11,12, can trans-regulate homologous and heterologous gene expression 13-17, and inhibits cellular transformation 18.  The acquisition of rep by HHV-6 could be due to natural transfer of genetic information between DNA viruses of eukaryotes and is likely to have important consequences for the life-cycle of HHV-6 and for host CD4 cell.
C1 UNIV CAMBRIDGE,DEPT PATHOL,DIV VIROL,CAMBRIDGE CB2 1QP,ENGLAND.
C3 University of Cambridge
RP THOMSON, BJ (corresponding author), NATL INST MED RES,DIV VIROL,RIDGEWAY,MILL HILL,LONDON NW7 1AA,ENGLAND.
NR 40
TC 110
Z9 125
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 78
EP 80
DI 10.1038/351078a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300065
PM 1851252
DA 2026-03-10
ER

PT J
AU TOUMI, R
   KERRIDGE, BJ
   PYLE, JA
AF TOUMI, R
   KERRIDGE, BJ
   PYLE, JA
TI HIGHLY VIBRATIONALLY EXCITED OXYGEN AS A POTENTIAL SOURCE OF OZONE IN THE UPPER-STRATOSPHERE AND MESOSPHERE
SO NATURE
LA English
DT Article
ID limb infrared monitor; nonlocal thermodynamic-equilibrium; hartley band photodissociation; water-vapor; energy-transfer; v3 mode; spectroscopy; dynamics
AB ONE of the main problems in atmospheric chemistry in recent years has been the discrepancy between theoretical model calculations of ozone concentrations and observations in the upper stratosphere and mesosphere 1.  It has been suggested 2 that the photolysis of vibrationally excited oxygen could provide an extra source of ozone and new laboratory data now allows us to test this hypothesis in two ways. First, by including the proposed mechanism in a numerical model of the atmosphere, we find that the production of odd oxygen is enhanced and that the calculated ozone concentrations are significantly increased so that they agree well with observations.  Second, we present a comparison between satellite observations of the daytime enhancement in the 6.9-mu-m emission from water vapour and theoretical calculations, which yields indirect evidence for the presence of vibrationally excited oxygen in the upper stratosphere and mesosphere; a significant fraction of which appears to be due to relaxation of very high vibrational levels.  Both these tests demonstrate that the proposed mechanism may indeed account for most of the discrepancy between model results and observations.
C1 RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND.
C3 UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory
RP TOUMI, R (corresponding author), UNIV CAMBRIDGE,DEPT CHEM,LENSFIELD RD,CAMBRIDGE CB2 1EW,ENGLAND.
NR 22
TC 37
Z9 39
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 217
EP 219
DI 10.1038/351217a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000051
DA 2026-03-10
ER

PT J
AU HARTLEY, SB
   CROSBIE, J
   BRINK, R
   KANTOR, AB
   BASTEN, A
   GOODNOW, CC
AF HARTLEY, SB
   CROSBIE, J
   BRINK, R
   KANTOR, AB
   BASTEN, A
   GOODNOW, CC
TI ELIMINATION FROM PERIPHERAL LYMPHOID-TISSUES OF SELF-REACTIVE LYMPHOCYTES-B RECOGNIZING MEMBRANE-BOUND ANTIGENS
SO NATURE
LA English
DT Article
ID protein tyrosine phosphorylation; transgenic mice; clonal deletion; cell tolerance; t-cells; receptor; expression; mature; stimulation; mechanisms
AB THE long-standing hypothesis 1,2 that tolerance to self antigens is mediated by either elimination 3-8 or functional inactivation (anergy; refs 9-11) of self-reactive lymphocytes is now accepted, but little is known about the factors responsible for initiating one process rather than the other. In the B-cell lineage, tolerant self-reactive cells persist in the peripheral lymphoid organs of transgenic mice expressing lysozyme and anti-lysozyme immunoglobulin genes 9, but are eliminated in similar transgenic mice expressing anti-major histocompatibility complex immunoglobulin genes 8. By modifying the structure of the lysozyme transgene and the isotype of the anti-lysozyme immunoglobulin genes, we demonstrate here that induction of anergy or deletion is not due to differences in antibody affinity or isotype, but to recognition of monomeric or oligomeric soluble antigen versus highly multivalent membrane-bound antigen. Our findings indicate that the degree of receptor crosslinking can have qualitatively distinct signalling consequences for lymphocyte development.
C1 STANFORD UNIV, HOWARD HUGHES MED INST, STANFORD, CA 94305 USA.
   STANFORD UNIV, DEPT MICROBIOL & IMMUNOL, STANFORD, CA 94305 USA.
   STANFORD UNIV, BECKMAN CTR MOLEC & GENET MED, DEPT GENET, STANFORD, CA 94305 USA.
C3 Stanford University; Howard Hughes Medical Institute; Stanford University; Stanford University
RP HARTLEY, SB (corresponding author), UNIV SYDNEY, CENTENARY INST CANC MED & CELL BIOL, SYDNEY, NSW 2006, AUSTRALIA.
NR 37
TC 613
Z9 738
U1 0
U2 11
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 765
EP 769
DI 10.1038/353765a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600072
PM 1944535
DA 2026-03-10
ER

PT J
AU SPERTINI, O
   KANSAS, GS
   MUNRO, JM
   GRIFFIN, JD
   TEDDER, TF
AF SPERTINI, O
   KANSAS, GS
   MUNRO, JM
   GRIFFIN, JD
   TEDDER, TF
TI REGULATION OF LEUKOCYTE MIGRATION BY ACTIVATION OF THE LEUKOCYTE ADHESION MOLECULE-1 (LAM-1) SELECTIN
SO NATURE
LA English
DT Article
ID node homing receptor; high endothelial venules; protein kinase-c; interaction domains; human homolog; lymphocytes; lfa-1; phosphorylation; mechanism; mac-1
AB A CENTRAL feature of host defence is the ability of leukocytes to enter tissues in response to immune or inflammatory stimuli.  The leukocyte adhesion molecule-1 (LAM-1) regulates the migration of human leukocytes by mediating the binding both of lymphocytes to high endothelial venules of peripheral lymph nodes and of neutrophils to endothelium at inflammatory sites 1-10.  As lymphocytes and neutrophils express the same LAM-1 protein 11,12, it is not clear how lineage-specific differences in leukocyte migration are controlled.  We now report that the affinity of LAM-1 for a carbohydrate-based ligand, PPME 13-16, is dramatically increased following lymphocyte and neutrophil activation by lineage-specific stimuli.  In addition, activation of lymphocytes by physiological stimuli enhanced LAM-1-dependent binding to high endothelial venules.  Thus, transient changes in LAM-1 affinity after leukocyte stimulation probably directly influence leukocyte migration.
C1 HARVARD UNIV,SCH MED,DEPT PATHOL,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,DEPT MED,BOSTON,MA 02115.
C3 Harvard University; Harvard Medical School; Harvard University; Harvard Medical School
RP SPERTINI, O (corresponding author), HARVARD UNIV,SCH MED,DANA FARBER CANC INST,DIV TUMOR IMMUNOL,BOSTON,MA 02115, USA.
NR 30
TC 288
Z9 316
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 691
EP 694
DI 10.1038/349691a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700046
PM 1705015
DA 2026-03-10
ER

PT J
AU RAHEMTULLA, A
   FUNGLEUNG, WP
   SCHILHAM, MW
   KUNDIG, TM
   SAMBHARA, SR
   NARENDRAN, A
   ARABIAN, A
   WAKEHAM, A
   PAIGE, CJ
   ZINKERNAGEL, RM
   MILLER, RG
   MAK, TW
AF RAHEMTULLA, A
   FUNGLEUNG, WP
   SCHILHAM, MW
   KUNDIG, TM
   SAMBHARA, SR
   NARENDRAN, A
   ARABIAN, A
   WAKEHAM, A
   PAIGE, CJ
   ZINKERNAGEL, RM
   MILLER, RG
   MAK, TW
TI NORMAL DEVELOPMENT AND FUNCTION OF CD8+ CELLS BUT MARKEDLY DECREASED HELPER-CELL ACTIVITY IN MICE LACKING CD4
SO NATURE
LA English
DT Article
ID embryonic stem-cells; toxic t-cell; homologous recombination; antigen expression; precursor cells; virus-infection; subsets; thymocytes; responses; invivo
AB T CELLs express T-cell antigen receptors (TCR) for the recognition of antigen in conjunction with the products of the major histocompatibility complex 1,2. They also express two key surface coreceptors, CD4 and CD8, which are involved in the interaction with their ligands 3,4. As CD4 is expressed on the early haemopoietic progenitor 5 as well as the early thymic precursor cells 6, a role for CD4 in haemopoiesis and T-cell development is implicated. Thymocytes undergo a series of differentiation 7 and selection steps 8,9 to become mature CD4+8- or CD4-8+ (single positive) T cells 10,11. Studies of the role of CD4+ T cells in vivo have been based on adoptive transfer of selected or depleted lymphocytes, or in vivo treatment of thymectomized mice with monoclonal antibodies causing depletion of CD4+ T cells 12-14. In order to study the role of the CD4 molecule in the development and function of lymphocytes, we have disrupted the CD4 gene in embryonic stem cells 15,16 by homologous recombination 17,18. Germ-like transmission 19,20 of the mutation produces mutant mouse strains that do not express CD4 on the cell surface. In these mice, the development of CD8+ T cells and myeloid components is unaltered, indicating that expression of CD4 on progenitor cells and CD4+ CD8+ (double positive) thymocytes is not obligatory. Here we report that these mice have markedly decreased helper cell activity for antibody responses, although cytotoxic T-cell activity against viruses is in the normal range. This differential requirement for CD4+ helper T cells is important to our understanding of immune disorders, including AIDS, in which CD4+ cells are reduced or absent.
C1 UNIV TORONTO, ONTARIO CANC INST, DEPT MED BIOPHYS & IMMUNOL, 500 SHERBOURNE ST, TORONTO M4X 1K9, ONTARIO, CANADA.
   UNIV ZURICH, INST PATHOL, CH-8091 ZURICH, SWITZERLAND.
C3 University of Toronto; University Health Network Toronto; University of Zurich
NR 34
TC 654
Z9 708
U1 0
U2 7
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 180
EP 184
DI 10.1038/353180a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100058
PM 1832488
DA 2026-03-10
ER

PT J
AU CHANTON, JP
   MARTENS, CS
   PAULL, CK
AF CHANTON, JP
   MARTENS, CS
   PAULL, CK
TI CONTROL OF PORE-WATER CHEMISTRY AT THE BASE OF THE FLORIDA ESCARPMENT BY PROCESSES WITHIN THE PLATFORM
SO NATURE
LA English
DT Article
ID isotopic composition; sulfate reduction; brine seeps; sulfur; sediments; sulfide
AB PORE waters collected from seep sediments hosting active chemosynthetic communities1,2 tend to be rich in sulphide, chloride and ammonium and depleted in sulphate relative to the concentrations in sea water.  To investigate the source of the energy-rich compounds and the processes causing low sulphate concentrations in seep-sediment pore waters, we have measured the sulphur isotope composition, delta-34S, of pore waters from seep sediments at the base of the West Florida escarpment.  The isotopic composition of pore-water sulphate remains approximately constant as its concentration is depleted, indicating that processes within the Florida platform, rather than microbial processes at seep sites, control pore-water chemistry in these sediments.  The composition of the seep brines, deduced from a linear mixing model, provides information on processes deep within the platform.
C1 UNIV N CAROLINA,MARINE SCI PROGRAM,CHAPEL HILL,NC 27599.
   UNIV N CAROLINA,DEPT GEOL,CHAPEL HILL,NC 27599.
C3 University of North Carolina; University of North Carolina Chapel Hill; University of North Carolina; University of North Carolina Chapel Hill
NR 34
TC 29
Z9 31
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 229
EP 231
DI 10.1038/349229a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900051
DA 2026-03-10
ER

PT J
AU HILL, AVS
   ALLSOPP, CEM
   KWIATKOWSKI, D
   ANSTEY, NM
   TWUMASI, P
   ROWE, PA
   BENNETT, S
   BREWSTER, D
   MCMICHAEL, AJ
   GREENWOOD, BM
AF HILL, AVS
   ALLSOPP, CEM
   KWIATKOWSKI, D
   ANSTEY, NM
   TWUMASI, P
   ROWE, PA
   BENNETT, S
   BREWSTER, D
   MCMICHAEL, AJ
   GREENWOOD, BM
TI COMMON WEST AFRICAN HLA ANTIGENS ARE ASSOCIATED WITH PROTECTION FROM SEVERE MALARIA
SO NATURE
LA English
DT Article
ID major histocompatibility complex; fragment-length-polymorphism; cd8+ t-cells; mhc polymorphism; mixed ancestry; dq antigens; selection; substitution; haplotypes; alleles
AB A large case-control study of malaria in West African children shows that a human leucocyte class I antigen (HLA-Bw53) and an HLA class II haplotype (DRB1*1302-DQB1*0501), common in West Africans but rare in other racial groups, are independently associated with protection from severe malaria. In this population they account for as great a reduction in disease incidence as the sickle-cell haemoglobin variant. These data support the hypothesis that the extraordinary polymorphism of major histocompatibility complex genes has evolved primarily through natural selection by infectious pathogens.
C1 MRC LABS, FAJARA, SENEGAMBIA.
   UNIV LONDON LONDON SCH HYG & TROP MED, DEPT EPIDEMIOL & POPULAT SCI, LONDON WC1E 7HT, ENGLAND.
   ROYAL VICTORIA HOSP, BANJUL, SENEGAMBIA.
C3 University of London; London School of Hygiene & Tropical Medicine
RP HILL, AVS (corresponding author), UNIV OXFORD, JOHN RADCLIFFE HOSP, INST MOLEC MED, MOLEC IMMUNOL GRP, OXFORD OX3 9DU, ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 75
TC 1279
Z9 1400
U1 0
U2 130
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 595
EP 600
DI 10.1038/352595a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100046
PM 1865923
DA 2026-03-10
ER

PT J
AU WOOD, BJ
   NELL, J
AF WOOD, BJ
   NELL, J
TI HIGH-TEMPERATURE ELECTRICAL-CONDUCTIVITY OF THE LOWER-MANTLE PHASE (MG,FE)O
SO NATURE
LA English
DT Article
ID solid-solutions; thermopower; pressure; wustite; oxide
AB THE electrical conductivity of the lower mantle, which controls the transmission of geomagnetic signals to the Earth's surface, has been the subject of recent controversy 1,2.  Peyronneau and Poirier 1 extrapolated high-pressure conductivity measurements of the lower-mantle assemblage (Mg,Fe)SiO3 perovskite plus (Mg,Fe)O magnesiowustite from 673 K to lower-mantle temperatures (2,200-2,500 K) to obtain conductivities consistent with geomagnetic observations (approximately 1 S m-1 at 1,000-km depth).  The high-pressure study of Li and Jeanloz 2 gave conductivities several orders of magnitude lower.  Here we report measurements of conductivity and thermopower of the iron-rich phase (Mg,Fe)O at high temperature (1,173-1,773 K) and controlled oxygen partial pressure (pO2). We find that pO2 has a very large influence on conductivity:  at fixed temperature and pressure, changes in pO2 can vary the conductivity by 1.5 orders of magnitude within the stability field of magnesiowustite.  For plausible mantle values of pO2, temperature and bulk composition, we obtain results in good agreement with those of ref. 1, indicating that magnesiowustite is the dominant conductor in the lower mantle and that observed upper- and lower-mantle conductivities can be produced by the same bulk composition.
RP WOOD, BJ (corresponding author), UNIV BRISTOL,DEPT GEOL,WILLS MEM BLDG,QUEENS RD,BRISTOL BS8 1RJ,ENGLAND.
NR 21
TC 55
Z9 62
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 309
EP 311
DI 10.1038/351309a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600057
DA 2026-03-10
ER

PT J
AU MALHOTRA, A
   THORPE, RS
AF MALHOTRA, A
   THORPE, RS
TI EXPERIMENTAL DETECTION OF RAPID EVOLUTIONARY RESPONSE IN NATURAL LIZARD POPULATIONS
SO NATURE
LA English
DT Article
ID geographic-variation; gallotia-galloti; selection; patterns; island; size
AB MANY studies of geographical variation within species 1-7, including those using numerical hypothesis tests 3-10, have demonstrated a relationship between patterns of phenotypic and environmental variation. But relatively few rigorously tested direct demonstrations of current selection in natural populations exist 11-14. Here we present evidence of a rapid response to selection from a field manipulation of the Dominican lizard, Anolis oculatus. There is considerable altitudinal and longitudinal variation in climate and vegetation on the island of Dominica 15. We have recorded complex patterns of geographic variation in morphology (body size and shape, colour pattern and scalation), which we have shown to correlate (both univariately and multivariately) with these patterns of ecological variation 16 by numerical hypothesis testing 10,17,18. Populations of several ecotypes of the species were translocated into large-scale experimental enclosures, and monitored over a period of two months. The magnitude of the difference in multivariate morphology between survivors and non-survivors within each enclosure was found to correlate with the magnitude of the difference between the ecological conditions of the enclosure site and the original habitats. Similar relationships were found for three indices of fitness of survivors.
RP MALHOTRA, A (corresponding author), UNIV ABERDEEN, DEPT ZOOL, TILLYDRONE AVE, ABERDEEN AB9 2TN, SCOTLAND.
NR 19
TC 73
Z9 81
U1 0
U2 15
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 347
EP 348
DI 10.1038/353347a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400058
DA 2026-03-10
ER

PT J
AU HARRINGTON, LA
   GREIDER, CW
AF HARRINGTON, LA
   GREIDER, CW
TI TELOMERASE PRIMER SPECIFICITY AND CHROMOSOME HEALING
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; terminal transferase; dna; tetrahymena; identification
AB CHROMOSOME healing by de novo telomere addition at non-telomeric sites has been well characterized in several organisms 1-9.  The Tetrahymena telomerase ribonucleoprotein uses an internal RNA template to catalyse d(TTGGGG)n telomere addition to the 3' end of telomeric sequence in vitro and in vivo 10,11.  Studies of telomerase RNA indicated that hybridization of the RNA template region, 5'-CAACCCCAA-3', to the 3' end of single-stranded telomeric oligonucleotides might be important for primer recognition and utilization 10.  The apparent requirement of telomerase for pre-existing telomeric sequence has raised questions regarding its role in chromosome healing 12,13.  We report here that Tetrahymena telomerase can specifically elongate single-stranded DNA oligonucleotides whose termini are not complementary to the RNA template sequence 5'-CAACCCCAA-3'.  These data suggest that telomerase may be able to heal chromosomes directly in vivo.
C1 COLD SPRING HARBOR LAB,POB 100,COLD SPRING HARBOR,NY 11724.
C3 Cold Spring Harbor Laboratory
NR 28
TC 161
Z9 189
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 451
EP 454
DI 10.1038/353451a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600064
PM 1896088
DA 2026-03-10
ER

PT J
AU PARK, JK
   ROSENSTEIN, YJ
   REMOLDODONNELL, E
   BIERER, BE
   ROSEN, FS
   BURAKOFF, SJ
AF PARK, JK
   ROSENSTEIN, YJ
   REMOLDODONNELL, E
   BIERER, BE
   ROSEN, FS
   BURAKOFF, SJ
TI ENHANCEMENT OF T-CELL ACTIVATION BY THE CD43 MOLECULE WHOSE EXPRESSION IS DEFECTIVE IN WISKOTT-ALDRICH SYNDROME
SO NATURE
LA English
DT Article
ID lymphocyte surface sialoglycoprotein; monoclonal-antibody; sialophorin cd43; human-leukocytes; leukosialin; proliferation; antigen; cd2; phosphorylation; receptor
AB CD43 (sialophorin, leukosialin, leukocyte large sialoglycoprotein), a heavily sialylated molecule found on most leukocytes and platelets, was initially identified as a major glycoprotein of mouse, rat and human T cells 1-8.  CD43 expression is defective on the T cells of males with the Wiskott-Aldrich syndrome, an X chromosome-linked recessive immunodeficiency disorder 9.  Affected males are susceptible to opportunistic infections and do not respond to polysaccharide antigens, reflecting defects in cytotoxic and helper T-cell functions.  Anti-CD43 monoclonal antibodies have a modest costimulatory effect on T cells, natural killer cells, B cells and monocytes 10-14, and one such antibody has been shown to activate T cells directly 15.  To investigate a possible physiological role for CD43, a complementary DNA encoding the human protein 16,17 was introduced into an antigen-responsive murine T-cell hybridoma 18.  We observed that CD43 enhances the antigen-specific activation of T cells and that the intracellular domain of CD43, which is hyperphosphorylated during T-cell activation 19-21, is required for this function.  We also found that antigen-presenting cells can bind specifically to immobilized purified CD43 and that the binding can be inhibited by liposomes containing CD43 as well as by anti-CD43 monoclonal antibodies.
C1 HARVARD UNIV,SCH MED,CTR BLOOD RES,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,DEPT PEDIAT,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,SCH MED,DIV HEMATOL,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,DEPT MED,BOSTON,MA 02115.
C3 Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Program in Cellular & Molecular Medicine (PCMM); Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School
RP PARK, JK (corresponding author), HARVARD UNIV,SCH MED,DANA FARBER CANC INST,DIV PEDIAT ONCOL,BOSTON,MA 02115, USA.
NR 26
TC 140
Z9 149
U1 0
U2 0
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 706
EP 709
DI 10.1038/350706a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000060
PM 2023632
DA 2026-03-10
ER

PT J
AU DUCLOS, SJ
   BRISTER, K
   HADDON, RC
   KORTAN, AR
   THIEL, FA
AF DUCLOS, SJ
   BRISTER, K
   HADDON, RC
   KORTAN, AR
   THIEL, FA
TI EFFECTS OF PRESSURE AND STRESS ON C60 FULLERITE TO 20 GPA
SO NATURE
LA English
DT Article
ID carbon
AB BULK C60 (fullerite) is a solid composed of extremely hard pseudospherical molecules bonded by weak van der Waals interactions.  We expect that pressurization will probe this diversity as the intermolecular distance is reduced.  Here we present experimental measurements of the room-temperature pressure-volume equation of state of C60 fullerite to pressures of 20 GPa.  The face-centered cubic phase remains stable under hydrostatic compression to this pressure, with an atmospheric-pressure isothermal bulk modulus of K0 = 18.1 +/- 1.8 GPa and dK0/dP = 5.7 +/- 0.6, characteristic of isotropic van der Waals intermolecular bonding.  X-ray diffraction intensity changes are consistent with the compressibility of the C60 molecule being significantly lower than that of the bulk fullerite solid.  Under non-hydrostatic compression, a transition to a crystallographic structure of lower symmetry is observed at 16 +/- 1 GPa.
C1 CORNELL UNIV,CORNELL HIGH ENERGY SYNCHROTRON SOURCE,ITHACA,NY 14853.
C3 Cornell University
RP DUCLOS, SJ (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 14
TC 360
Z9 365
U1 2
U2 34
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 380
EP 382
DI 10.1038/351380a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600049
DA 2026-03-10
ER

PT J
AU ALLARD, P
   CARBONNELLE, J
   DAJLEVIC, D
   LEBRONEC, J
   MOREL, P
   ROBE, MC
   MAURENAS, JM
   FAIVREPIERRET, R
   MARTIN, D
   SABROUX, JC
   ZETTWOOG, P
AF ALLARD, P
   CARBONNELLE, J
   DAJLEVIC, D
   LEBRONEC, J
   MOREL, P
   ROBE, MC
   MAURENAS, JM
   FAIVREPIERRET, R
   MARTIN, D
   SABROUX, JC
   ZETTWOOG, P
TI ERUPTIVE AND DIFFUSE EMISSIONS OF CO2 FROM MOUNT ETNA
SO NATURE
LA English
DT Article
ID kilauea volcano; sulfur-dioxide; carbon-dioxide; atmosphere
AB MOUNT Etna, in Sicily, is one of the world's most actively degassing volcanoes 1.  Here we use data collected from 1975 to 1987 to estimate carbon dioxide emissions from the summit craters and the upper flanks of the volcano.  By combining measurements of the SO2 flux in the plume (refs 1-6 and this paper) with measurements of the CO2/SO2 ratio of the plume gases, we find that the average output of CO2 from summit crater degassing is 13 +/- 3 Tg yr-1.  This is an order of magnitude higher than the annual CO2 output from Kilauea 7,8, Hawaii, and representative arc volcanoes 9,10.  Furthermore, we find that diffuse emissions of CO2 from the upper flanks of Etna are magma-derived and are of a similar magnitude to those emitted from the crater plume.  This observation, as well as others 11-14, verifies the idea 15 that extensive diffuse release of magmatic CO2 may occur in volcanically active regions - a process that needs to be taken into account when evaluating the volatile budget of subaerial volcanism.  Such degassing may be of use for monitoring volcanic activity, could provide a means for radiocarbon dating of eruptions, and may be a mechanism by which CO2 is injected into crater lakes.
C1 CEA,IPSN,SPIN,DPT,F-91198 GIF SUR YVETTE,FRANCE.
   CEN,LESI,F-38041 GRENOBLE,FRANCE.
   CTR RECH PHYS ATMOSPHERE,EERM,F-78470 MAGNY LES HAMEAUX,FRANCE.
C3 CEA; Universite Paris Saclay
RP ALLARD, P (corresponding author), CEA,CNRS,CTR FAIBLES RADIOACTIV,F-91198 GIF SUR YVETTE,FRANCE.
NR 37
TC 450
Z9 465
U1 0
U2 45
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 387
EP 391
DI 10.1038/351387a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600052
DA 2026-03-10
ER

PT J
AU CHADWICK, WW
   EMBLEY, RW
   FOX, CG
AF CHADWICK, WW
   EMBLEY, RW
   FOX, CG
TI EVIDENCE FOR VOLCANIC-ERUPTION ON THE SOUTHERN JUAN-DE-FUCA RIDGE BETWEEN 1981 AND 1987
SO NATURE
LA English
DT Article
AB THE formation of new ocean crust at mid-ocean ridges is known to be a discontinuous process in both space and time, but little is known about the frequency and duration of eruptions along an active ridge segment.  Here we present evidence, from Sea Beam surveys and underwater photography, for the eruption of lavas along a segment of the Juan de Fuca ridge between 1981 and 1987.  Although previous studies have inferred volcanic activity on ridges in areas where recent seismicity or young lava flows have been observed 1-4, none has yet had direct evidence to date such a recent submarine eruption.  The temporal coincidence between this eruptive episode and the megaplumes (huge, sudden emissions of hot mineral-laden water) observed over this part of the ridge 5,6 in 1986 and 1987 supports previous suggestions 5-10 that megaplumes are caused by sea-floor spreading events.
C1 NOAA,HATFIELD MARINE SCI CTR,PACIFIC MARINE ENVIRONM LAB,NEWPORT,OR 97365.
C3 National Oceanic Atmospheric Admin (NOAA) - USA
RP CHADWICK, WW (corresponding author), OREGON STATE UNIV,CIMRS,HATFIELD MARINE SCI CTR,NEWPORT,OR 97365, USA.
NR 14
TC 91
Z9 96
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 416
EP 418
DI 10.1038/350416a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200047
DA 2026-03-10
ER

PT J
AU TANABE, T
   ADAMS, BA
   NUMA, S
   BEAM, KG
AF TANABE, T
   ADAMS, BA
   NUMA, S
   BEAM, KG
TI REPEAT-I OF THE DIHYDROPYRIDINE RECEPTOR IS CRITICAL IN DETERMINING CALCIUM-CHANNEL ACTIVATION KINETICS
SO NATURE
LA English
DT Article
ID sodium-channel; skeletal-muscle; potassium channels; expression; membrane; cdna
AB MEMBRANE depolarization causes many kinds of ion channels to open, a process termed activation 1. For both Na+ channels 2-4 and Ca2+ channels 5,6, kinetic analysis of current has suggested that during activation the channel undergoes several conformational changes before reaching the open state. Structurally, these channels share a common motif 7: the central element is a large polypeptide with four repeating units of homology (repeats I-IV), each containing a voltage-sensing region, the S4 segment 8-11. This suggests that the distinct conformational transitions inferred from kinetic analysis may be equated with conformational changes of the individual structural repeats 8. To investigate the molecular basis of channel activation, we constructed complementary DNAs encoding chimaeric Ca2+ channels in which one or more of the four repeats of the skeletal muscle dihydropyridine receptor are replaced by the corresponding repeats derived from the cardiac dihydropyridine receptor. We report here that repeat I determines whether the chimaeric Ca2+ channel shows slow (skeletal muscle-like) 12 or rapid (cardiac-like) 13 activation.
C1 KYOTO UNIV, FAC MED, DEPT MED CHEM, KYOTO 606, JAPAN.
   KYOTO UNIV, FAC MED, DEPT MOLEC GENET, KYOTO 606, JAPAN.
   COLORADO STATE UNIV, COLL VET MED & BIOMED SCI, DEPT PHYSIOL, FT COLLINS, CO 80523 USA.
C3 Kyoto University; Kyoto University; Colorado State University System; Colorado State University Fort Collins
NR 27
TC 123
Z9 130
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 800
EP 803
DI 10.1038/352800a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400059
PM 1652692
DA 2026-03-10
ER

PT J
AU GARCIA, JV
   MILLER, AD
AF GARCIA, JV
   MILLER, AD
TI SERINE PHOSPHORYLATION-INDEPENDENT DOWN-REGULATION OF CELL-SURFACE CD4 BY NEF
SO NATURE
LA English
DT Article
ID human immunodeficiency virus; htlv-iii; t-cells; protein; pathogenesis; modulation; type-1
AB A DECLINE in the T-cell population usually marks the onset of progressive immunological disease in individuals infected with the human immunodeficiency virus (HIV).  Because CD4+ cells help to coordinate efficient immune responses, some of the defects in the immune function in advanced cases of AIDS may be explained by the disappearance of these cells.  Therefore, an understanding of the mechanisms used by HIV to induce the reduction of CD4+ cells is important.  Here we use a Moloney murine leukaemia virus-based retroviral vector in order to express the nef gene of HIV-1 in three lymphocytic cell lines expressing CD4.  In all cases we find that cell-surface CD4 expression is inversely related to nef expression.  However, nef does not alter steady-state levels of CD4 RNA or CD4 protein.  Also, nef can downregulate a CD4 triple mutant (Ser --> Ala) that is neither phosphorylated nor down-regulated by phorbol esters, indicating that nef is acting by a different mechanism.
RP GARCIA, JV (corresponding author), FRED HUTCHINSON CANC RES CTR,PROGRAM MOLEC MED,SEATTLE,WA 98104, USA.
NR 18
TC 723
Z9 849
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 508
EP 511
DI 10.1038/350508a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300054
PM 2014052
DA 2026-03-10
ER

PT J
AU ELTHON, D
AF ELTHON, D
TI GEOCHEMICAL EVIDENCE FOR FORMATION OF THE BAY-OF-ISLANDS OPHIOLITE ABOVE A SUBDUCTION ZONE
SO NATURE
LA English
DT Article
ID north arm mountain; western newfoundland; coastal complex; basalts; gabbros; genesis; origin
AB THE Bay of Islands (BOI) complex in western Newfoundland is one of the world's best-known ophiolites, and has generally been interpreted as a fragment of ocean floor emplaced on the eastern margin of North America 1,2 . The similarities of the BOI to lithosphere formed at mid-ocean ridges has led many investigators to use the BOI as an onland laboratory in which to study the geochemical, tectonic and geophysical properties of the oceanic lithosphere 1-9. There have been, nonetheless, a few suggestions that the BOI ophiolite formed above a subduction zone 10-12, as have most other ophiolites 13-15. Here I report the existence of a substantial tantalum depletion in BOI magmas; Jenner et al. 16 demonstrate that BOI magmas have a niobium depletion as well. These depletions are characteristic of magmas erupted above subduction zones but not at mid-ocean ridges, indicating that the BOI is not, after all, a good analogue for lithosphere formed at mid-ocean ridges.
RP ELTHON, D (corresponding author), UNIV HOUSTON,DEPT CHEM,HOUSTON,TX 77204, USA.
NR 35
TC 89
Z9 106
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 140
EP 143
DI 10.1038/354140a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000057
DA 2026-03-10
ER

PT J
AU KITAMURA, D
   ROES, J
   KUHN, R
   RAJEWSKY, K
AF KITAMURA, D
   ROES, J
   KUHN, R
   RAJEWSKY, K
TI A B-CELL-DEFICIENT MOUSE BY TARGETED DISRUPTION OF THE MEMBRANE EXON OF THE IMMUNOGLOBULIN MU-CHAIN GENE
SO NATURE
LA English
DT Article
ID pre-b; monoclonal-antibody; lymphocytes-b; heavy-chains; light-chain; bone-marrow; stem-cells; rearrangement; lambda-5; locus
AB OF the various classes of antibodies that B lymphocytes can produce, class M (IgM) is the first to be expressed on the membrane of the developing cells.  Pre-B cells, the precursors of B-lymphocytes, produce the heavy chain of IgM (mu-chain), but not light chains 1.  Recent data suggest that pre-B cells express mu-chains on the membrane together with the 'surrogate' light chains lambda-5 and VpreB (refs 2-7).  This complex could control pre-B-cell differentiation, in particular the rearrangement of the light-chain genes 8.  We have now assessed the importance of the membrane form of the mu-chain in B-cell development by generating mice lacking this chain.  We disrupted one of the membrane exons of the gene encoding the mu-chain constant region by gene targeting 9 in mouse embryonic stem cells 10.  From these cells we derived mice heterozygous or homozygous for the mutation.  B-cell development in the heterozygous mice seemed to be normal, but in homozygous animals B cells were absent, their development already being arrested at the stage of pre-B-cell maturation.
C1 UNIV COLOGNE,INST GENET,WEYERTAL 121,W-5000 COLOGNE 41,GERMANY.
C3 University of Cologne
NR 29
TC 1626
Z9 1851
U1 0
U2 18
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 423
EP 426
DI 10.1038/350423a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200050
PM 1901381
DA 2026-03-10
ER

PT J
AU GIER, TE
   STUCKY, GD
AF GIER, TE
   STUCKY, GD
TI LOW-TEMPERATURE SYNTHESIS OF HYDRATED ZINCO(BERYLLO)-PHOSPHATE AND ARSENATE MOLECULAR-SIEVES
SO NATURE
LA English
DT Article
ID crystal-structure; naznpo4
AB ALUMINOSILICATE (zeolite) molecular sieves, both natural and synthetic, have been studied extensively because of their utility in commercial processes such as petroleum cracking, water treatment and gas absorption 1-3.  Although aluminium and silicon may be replaced by a variety of other tetrahedrally coordinated elements, there are few examples of molecular sieves that contain neither aluminium nor silicon: several gallophosphates are known 4,5, and cacoxenite, a basic ferric oxyphosphate, occurs naturally 6.  Recently, two new beryllophosphate minerals have been identified 7,8:  tiptopite, isotypic with cancrinite, and pahasapaite (Li, Ca beryllophosphate), which has the structure of zeolite RHO.  Harvey and Meier 9 have prepared five new beryllophosphates, with structures analogous to RHO (Li), gismondine (Na), edingtonite (K), pollucite (Cs), and a new structure, BPH, that has no aluminosilicate analogue.  Here we describe the preparation of new families of hydrated zincophosphates/arsenates and beryllophosphates/arsenates with structures that are also related to zeolitic aluminosilicates.  These materials may be prepared from gels over a much wider range of pH and at much lower temperatures than are possible for aluminophosphates, perhaps because of the greater solubility of the framework elements:  analogues of hydrosodalite and zeolites RHO, Li-A(BW) and X are easily prepared at pH values ranging from 2 to 12 and between 4 and 100-degrees-C.  Growth of crystals adequate for X-ray structural analyses seems to be easier than is the case for aluminosilicate/phosphate materials.
C1 UNIV CALIF SANTA BARBARA,DEPT CHEM,SANTA BARBARA,CA 93106.
C3 University of California System; University of California Santa Barbara
RP GIER, TE (corresponding author), DUPONT CO,EXPTL STN,DEPT CENT RES & DEV,WILMINGTON,DE 19880, USA.
NR 14
TC 375
Z9 388
U1 1
U2 78
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 508
EP 510
DI 10.1038/349508a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100060
DA 2026-03-10
ER

PT J
AU VANDERHILST, R
   ENGDAHL, R
   SPAKMAN, W
   NOLET, G
AF VANDERHILST, R
   ENGDAHL, R
   SPAKMAN, W
   NOLET, G
TI TOMOGRAPHIC IMAGING OF SUBDUCTED LITHOSPHERE BELOW NORTHWEST PACIFIC ISLAND ARCS
SO NATURE
LA English
DT Article
ID wave travel time; 3-dimensional seismic structure; lower mantle beneath; high-velocity zone; slab penetration; lateral heterogeneity; japan islands; deep; discontinuity; earthquakes
AB The seismic tomography problem does not have a unique solution, and published tomographic images have been equivocal with regard to the deep structure of subducting slabs. An improved tomographic method, using a more realistic background Earth model and surface-reflected as well as direct seismic phases, shows that slabs beneath the Japan and Izu Bonin island arcs are deflected at the boundary between upper and lower mantle, whereas those beneath the northern Kuril and Mariana arcs sink into the lower mantle.
C1 US GEOL SURVEY,NATL EARTHQUAKE INFORMAT CTR,DENVER FED CTR,DENVER,CO 80225.
   STATE UNIV UTRECHT,DEPT THEORET GEOPHYS,3508 TA UTRECHT,NETHERLANDS.
C3 United States Department of the Interior; United States Geological Survey; Utrecht University
RP VANDERHILST, R (corresponding author), UNIV LEEDS,DEPT EARTH SCI,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND.
NR 53
TC 437
Z9 438
U1 1
U2 51
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 37
EP 43
DI 10.1038/353037a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500049
DA 2026-03-10
ER

PT J
AU DAWSON, TE
   EHLERINGER, JR
AF DAWSON, TE
   EHLERINGER, JR
TI STREAMSIDE TREES THAT DO NOT USE STREAM WATER
SO NATURE
LA English
DT Article
AB A LONG-STANDING axiom is that plant distribution is strongly influence by soil moisture content 1, 2.  While it has been shown that plant taxa inhabiting streamside communities receive or use more water 3, it is assumed that this water is obtained from the stream adjacent to where they are found growing.  Here we show, using hydrogen isotope ratio analyses at natural abundance levels, that mature streamside trees growing in or directly next to a perennial stream used little or none of the surface stream water.  The deuterium to hydrogen content of both source and xylem waters indicated that mature trees were using waters from deeper strata.  Although adult trees may have roots distributed continuously throughout a soil profile, it seemed that the most active sites of water absorption were limited to deeper soil layers.  In contrast, small streamside individuals appeared to use stream water, whereas small non-streamside individuals used recent precipitation as their primary water source.  Our analyses provide both a relatively non-destructive method for assessing water sources of plants and a means of assessing potential competitive interactions among co-occurring taxa. In addition, the method may aid in resolving the role of water in determining plant distributions in areas characterized by sharp soil moisture gradients.
C1 UNIV UTAH,DEPT BIOL,SALT LAKE CITY,UT 84112.
   UNIV UTAH,STABLE ISOTOPE RATIO FACIL ENVIRONM RES,SALT LAKE CITY,UT 84112.
C3 Utah System of Higher Education; University of Utah; Utah System of Higher Education; University of Utah
NR 17
TC 687
Z9 864
U1 1
U2 155
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 335
EP 337
DI 10.1038/350335a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800090
DA 2026-03-10
ER

PT J
AU ISACOFF, EY
   JAN, YN
   JAN, LY
AF ISACOFF, EY
   JAN, YN
   JAN, LY
TI PUTATIVE RECEPTOR FOR THE CYTOPLASMIC INACTIVATION GATE IN THE SHAKER K+ CHANNEL
SO NATURE
LA English
DT Article
ID potassium channels; sodium-channel; drosophila muscle; xenopus-oocytes; rat-brain; cloning
AB INACTIVATION of ion channels is important in the control of membrane excitability. For example, delayed-rectifier K+ channels, which regulate action potential repolarization, are inactivated only slowly, whereas A-type K+ channels, which affect action potential duration and firing frequency, have both fast and slow inactivation 1.  Fast inactivation of Na+ and K+ channels may result from the blocking of the permeation pathway by a positively charged cytoplasmic gate 2 such as the one encoded by the first 20 amino acids of the Shaker B (ShB) K+ channel 3,4.  We report here that mutation of five highly conserved residues between the proposed membrane-spanning segments S4 and S5 (also termed H4) 5 of ShB affects the stability of the inactivated state and alters channel conductance. One such mutation stabilizes the inactivated state of ShB as well as the inactivated state induced in the delayed-rectifier type K+ channel drk1 (ref. 6) by the cytoplasmic application of the ShB N-terminal peptide. The S4-S5 loop, therefore, probably forms part of a receptor for the inactivation gate and lies near the channel's permeation pathway.
C1 UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143.
   UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM,SAN FRANCISCO,CA 94143.
C3 University of California System; University of California San Francisco; University of California System; University of California San Francisco
RP ISACOFF, EY (corresponding author), UNIV CALIF SAN FRANCISCO,HOWARD HUGHES MED INST,SAN FRANCISCO,CA 94143, USA.
NR 30
TC 314
Z9 339
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 86
EP 90
DI 10.1038/353086a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500066
PM 1881453
DA 2026-03-10
ER

PT J
AU MCDONALD, NQ
   LAPATTO, R
   MURRAYRUST, J
   GUNNING, J
   WLODAWER, A
   BLUNDELL, TL
AF MCDONALD, NQ
   LAPATTO, R
   MURRAYRUST, J
   GUNNING, J
   WLODAWER, A
   BLUNDELL, TL
TI NEW-PROTEIN FOLD REVEALED BY A 2.3-A RESOLUTION CRYSTAL-STRUCTURE OF NERVE GROWTH-FACTOR
SO NATURE
LA English
DT Article
ID neurotrophic factor; molecular-cloning; factor receptor; neurotoxin; binding
AB NERVE growth factor (NGF) 1 is a member of an expanding family of neurotrophic factors (including brain-derived neurotrophic factor 2 and the neurotrophins 3,4) that control the development and survival of certain neuronal populations both in the peripheral and in the central nervous systems 5. Its biological effects are mediated by a high-affinity ligand-receptor interaction and a tyrosine kinase signalling pathway 6,7. A potential use for NGF and its relatives in the treatment of neurological disorders such as Alzheimer's disease 8 and Parkinson's disease 9 requires an understanding of the structure-function relationships of NGF. NGF is a dimeric molecule, with 118 amino acids per protomer. We report the crystal structure of the murine NGF dimer at 2.3-angstrom resolution, which reveals a novel protomer structure consisting of three antiparallel pairs of beta-strands, together forming a flat surface. Two subunits associate through this surface, thus burying a total of 2,332 angstrom 2. Four loop regions, which contain many of the variable residues observed between different NGF-related molecules, may determine the different receptor specificities. A clustering of positively charged side chains may provide a complementary interaction with the acidic low-affinity NGF receptor. The structure provides a model for rational design of analogues of NGF and its relatives and for testing the NGF-receptor recognition determinants critical for signal transduction.
C1 UNIV LONDON BIRKBECK COLL,IMPERIAL CANC RES FUND,STRUCT MOLEC BIOL UNIT,MALET ST,LONDON WC1E 7HX,ENGLAND.
   UNIV LONDON BIRKBECK COLL,DEPT CRYSTALLOG,LONDON WC1E 7HX,ENGLAND.
   NCI,FREDERICK CANC RES & DEV CTR,ABL,BASIC RES PROGRAM,FREDERICK,MD 21701.
C3 University of London; Birkbeck University London; Cancer Research UK; University of London; Birkbeck University London; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); Science Applications International Corporation (SAIC); SAIC-Frederick
NR 39
TC 451
Z9 535
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 411
EP 414
DI 10.1038/354411a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100057
PM 1956407
DA 2026-03-10
ER

PT J
AU LAWLOR, DA
   DICKEL, CD
   HAUSWIRTH, WW
   PARHAM, P
AF LAWLOR, DA
   DICKEL, CD
   HAUSWIRTH, WW
   PARHAM, P
TI ANCIENT HLA GENES FROM 7,500-YEAR-OLD ARCHAEOLOGICAL REMAINS
SO NATURE
LA English
DT Article
ID molecular analysis; chain-reaction; dna-sequences; mummy dna; alleles; cloning; number; evolution; family; brain
AB IN the past decade there has been increasing interest in cloning DNA from ancient and preserved tissues 1-6.  Most studies, however, have focused on mitochondrial or chloroplast genes, present at hundreds to thousands of copies per cell compared with one or two for each nuclear gene 7-9.  With a probe containing Alu repeat sequences, Paabo isolated a 3.4-kilobase DNA fragment from a 2,400-year-old Egyptian mummy 10 which was subsequently shown to contain an intron of the nuclear gene HLA-DQA (ref. 11).  Here we report a more targeted approach to the characterization of nuclear genes from archaeological specimens.  The Windover pond of central Florida has provided skeletal and soft tissue remains from 165 humans, radiocarbon-dated to be 6,990-8,130 years old 12-14.  Using DNA obtained from one individual we have characterized segments from six nuclear genes:  that for beta-2-microglobulin and five members of the class I HLA heavy chain gene family.  Distinctive patterns of nucleotide substitution in the cloned heavy chain gene segments permit tentative assignment of the HLA-A,B type of the ancient individual.
C1 STANFORD UNIV,DEPT CELL BIOL,STANFORD,CA 94305.
   STANFORD UNIV,DEPT MICROBIOL & IMMUNOL,STANFORD,CA 94305.
   UNIV FLORIDA,COLL MED,DEPT IMMUNOL & MED MICROBIOL,GAINESVILLE,FL 32610.
   UNIV FLORIDA,COLL MED,DEPT OPHTHALMOL,GAINESVILLE,FL 32610.
C3 Stanford University; Stanford University; State University System of Florida; University of Florida; State University System of Florida; University of Florida
NR 30
TC 96
Z9 103
U1 1
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 785
EP 788
DI 10.1038/349785a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600054
PM 2000147
DA 2026-03-10
ER

PT J
AU LOWNDES, NF
   JOHNSON, AL
   JOHNSTON, LH
AF LOWNDES, NF
   JOHNSON, AL
   JOHNSTON, LH
TI COORDINATION OF EXPRESSION OF DNA-SYNTHESIS GENES IN BUDDING YEAST BY A CELL-CYCLE REGULATED TRANS FACTOR
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; ho gene; periodic transcription; gel-electrophoresis; ligase genes; cdc9; identification; activation; sequences; binding
AB ALL of the DNA synthesis genes of budding yeast examined so far are periodically expressed and hence under cell-cycle control (Table 1).  Expression occurs near the G1/S phase boundary and the genes seem to be coordinately regulated (reviewed in ref. 4).  The upstream promoter sequences of these genes have only a hexamer element, ACGCGT (an MluI restriction site), in common.  Here we show that this hexamer is able to impart periodic expression to a heterologous gene and, significantly, this expression occurs coincidentally with that of CDC9, one of the DNA synthesis genes (Table 1).  We have also identified a protein that binds specifically to these sequences in a similar periodic manner.  These ACGCGT sequences and the transcription factor that binds to them therefore seem to be the elements controlling both the periodic expression and coordinate regulation of the DNA synthesis genes.
C1 NATL INST MED RES,CELL PROPAGAT LAB,RIDGEWAY,MILL HILL,LONDON NW7 1AA,ENGLAND.
C3 MRC National Institute for Medical Research
NR 27
TC 185
Z9 193
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 247
EP 250
DI 10.1038/350247a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900063
PM 2005980
DA 2026-03-10
ER

PT J
AU PENG, TH
   BROECKER, WS
AF PENG, TH
   BROECKER, WS
TI DYNAMIC LIMITATIONS ON THE ANTARCTIC IRON FERTILIZATION STRATEGY
SO NATURE
LA English
DT Article
ID radiocarbon; ocean
AB MARTIN et al. have proposed an ingenious means by which the rise in atmospheric CO2 content generated by the burning of fossil fuels and deforesation might be partially compensated.  The idea is that plant production in the nutrient-rich surface waters of the Antarctic could be stimulated by the addition of dissolved iron, thereby reducing the CO2 partial pressure in these waters and allowing CO2 to flow from the atmosphere into the Antarctic Ocean.  We have used a box model calibrated with transient tracer data to examine the dynamical aspects of this proposal, and conclude that after 100 years of totally successful fertilization the CO2 content of the atmosphere would be lowered by only 10 +/- 5% below what it would have been in the absence of fertilization.  So if after 100 years the CO2 content of the atmosphere were 500 mu-atm without fertilization, it would be between 425 and 475 mu-atm with full fertilization.  In other words, if our model calibration is correct, even if iron fertilization worked perfectly it would not significantly reduce the atmospheric CO2 content.
C1 COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964.
C3 Columbia University
RP PENG, TH (corresponding author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA.
NR 14
TC 73
Z9 76
U1 1
U2 31
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 227
EP 229
DI 10.1038/349227a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900050
DA 2026-03-10
ER

PT J
AU WOOLHOUSE, MEJ
   TAYLOR, P
   MATANHIRE, D
   CHANDIWANA, SK
AF WOOLHOUSE, MEJ
   TAYLOR, P
   MATANHIRE, D
   CHANDIWANA, SK
TI ACQUIRED-IMMUNITY AND EPIDEMIOLOGY OF SCHISTOSOMA-HAEMATOBIUM
SO NATURE
LA English
DT Article
ID highveld region; mansoni; infection; resistance; responses; dynamics; mice; schoolchildren; transmission; reinfection
AB HUMAN immune responses to schistosome infection have been characterized in detail 1-5.  But there has been controversy 6 over the relative importance of ecological factors (variation in exposure to infection) and immunological factors (acquired immunity) in determining the relationships between levels of infection and age typically found in areas where infection is endemic 7,8.  Independent effects of exposure and age on the rates of reinfection with Schistosoma haematobium after chemotherapy have been demonstrated in the Gambia 9 and Zimbabwe 8.  This age effect could be the result of acquired immunity to infection. Indeed, allowing for variation in exposure and age, low rates of reinfection in the Gambia are correlated with high amounts of specific IgE antibodies 10 -human IgE can kill S. mansoni schistosomulae in vitro 11.  Further, animals can acquire immunologically mediated resistance to S. mansoni infection 12,14, although nonimmunological factors could also be involved 15.  Acquisition of this immunity seems to be related to the cumulative effects of repeated infection and provides only partial protection 12,13,16.  These characteristics are consistent with immuno-epidemiological data for both S. mansoni and S. haematobium infections of humans 4,17. We have now analysed age-prevalence data for human infection with S. haematobium, and find patterns of variation that are indeed consistent with the epidemiological effects of acquired immunity predicted by mathematical models.
C1 UNIV ZIMBABWE,TRAINING CTR WATER & SANITAT,HARARE,ZIMBABWE.
   BLAIR RES LAB,HARARE,ZIMBABWE.
C3 University of Zimbabwe
RP WOOLHOUSE, MEJ (corresponding author), UNIV OXFORD,DEPT ZOOL,S PARKS RD,OXFORD OX1 3PS,ENGLAND.
NR 27
TC 135
Z9 141
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 757
EP 759
DI 10.1038/351757a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100068
PM 1905786
DA 2026-03-10
ER

PT J
AU CARLISLE, DB
   BRAMAN, DR
AF CARLISLE, DB
   BRAMAN, DR
TI NANOMETER-SIZE DIAMONDS IN THE CRETACEOUS TERTIARY BOUNDARY CLAY OF ALBERTA
SO NATURE
LA English
DT Article
ID impact; extinctions; canada
AB STARTING with the discovery of an iridium anomaly at the Cretaceous/Tertiary boundary in Italy 1, the idea that a large asteroid or comet struck the Earth at the end of the Cretaceous period has gained wide acceptance 2-4 although some workers suggest that massive volcanic eruptions can also explain the observations 5. The abundance of small diamonds, 3-5 nm in size, in chondritic meteorites 6,7 prompted us to search for such diamonds in the Cretaceous/Tertiary boundary clay of the Red Deer Valley of Alberta (the 'Knudsen's farm' locality). Dissolution and oxidation of this clay yielded 45 ng g-1 of a white fraction, consisting of more than 97% carbon, which was absent from rocks above and below the boundary layer. We present evidence that this material is indeed diamond, which strengthens further the case for an extraterrestrial impact. The diamond/iridium ratio in the boundary clay may constrain the type of impactor; our estimate (1.22:1) is close to the value found in type C2 chondritic meteorites 2.
C1 ROYAL TYRRELL MUSEUM PALAEONTOL ALBERTA CULTURE & MULTICULTURALISM,DRUMHELLEER T0Y 0J0,ALBERTA,CANADA.
RP CARLISLE, DB (corresponding author), ENVIRONM CANADA,OTTAWA K1A 0H3,ONTARIO,CANADA.
NR 19
TC 56
Z9 62
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 708
EP 709
DI 10.1038/352708a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400055
DA 2026-03-10
ER

PT J
AU EDGINGTON, DN
   KLUMP, JV
   ROBBINS, JA
   KUSNER, YS
   PAMPURA, VD
   SANDIMIROV, IV
AF EDGINGTON, DN
   KLUMP, JV
   ROBBINS, JA
   KUSNER, YS
   PAMPURA, VD
   SANDIMIROV, IV
TI SEDIMENTATION-RATES, RESIDENCE TIMES AND RADIONUCLIDE INVENTORIES IN LAKE BAIKAL FROM CS-137 AND PB-210 IN SEDIMENT CORES
SO NATURE
LA English
DT Article
ID great-lakes; model; michigan
AB RADIONUCLIDES in lake sediments may act as indicators of the sedimentation rate of particles on which they are adsorbed; these rates in turn provide a direct indication of the residence times of particles in the water column.  The radionuclide Cs-137 is anthropogenic (an atomic-bomb product), so that its concentration in sediments also reveals the input history of this species and thus a record of atmospheric contamination by this nuclide in the lake's watershed.  Here we report measurements of Cs-137 and the natural radionuclide Pb-210 in cores from several stations throughout the three basins of Lake Baikal. The results confirm earlier indirect estimates 1 of the mean sedimentation rate, and show that the effective settling rate of these radionuclides is the same as that in the Great Lakes; the longer residence times for Lake Baikal are therefore simply a consequence of its greater depth.  As well as allowing estimates of fluxes at the sediment-water interface 2-4, our results provide information on the timing of palaeolimnological events 5, on the existence of different depositional zones throughout the lake, on the long-term (decadal) diffusion of nuclides in sediments 6 and for the development of mass-balance models for sediments and contaminants 7-9.
C1 NOAA,GREAT LAKES ENVIRONM RES LAB,ANN ARBOR,MI.
   ACAD SCI USSR,INST GEOCHEM,IRKUTSK 664003,USSR.
   ACAD SCI USSR,INST LIMNOL,IRKUTSK 664003,USSR.
C3 National Oceanic Atmospheric Admin (NOAA) - USA; Russian Academy of Sciences; Irkutsk Science Centre of the Russian Academy of Sciences; A.P. Vinogradov Institute of Geochemistry of the Siberian Branch of the RAS; Irkutsk Science Centre of the Russian Academy of Sciences; Russian Academy of Sciences; Limnological Institute SB RAS
RP EDGINGTON, DN (corresponding author), UNIV WISCONSIN,CTR GREAT LAKES STUDIES,MILWAUKEE,WI 53201, USA.
NR 33
TC 134
Z9 147
U1 0
U2 40
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 601
EP 604
DI 10.1038/350601a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200057
DA 2026-03-10
ER

PT J
AU TENG, DHF
   ENGELE, CM
   VENKATESH, TR
AF TENG, DHF
   ENGELE, CM
   VENKATESH, TR
TI A PRODUCT OF THE PRUNE LOCUS OF DROSOPHILA IS SIMILAR TO MAMMALIAN GTPASE-ACTIVATING PROTEIN
SO NATURE
LA English
DT Article
ID nucleoside diphosphate kinase; tumor-metastasis; awd proteins; ras p21; gap; gene; dna; melanogaster; elements; cloning
AB THE X-linked prune (pn) eye-colour mutation of Drosophila melanogaster has a highly specific, complementary lethal interaction with the conditional dominant Killer of prune (awd(K-pn)) mutation 1,2.  Although awd(K-pn) flies have no apparent phenotype on their own, pn awd(K-pn) double mutants die as second or third larval instars.   The awd locus encodes a nucleoside diphosphate kinase 3, an enzyme that catalyses the transfer of high-energy phosphate bonds between nucleoside diphosphates and nucleoside triphosphates 4, which is essential for the normal development of Drosophila.  Analysis of the pn locus has suggested that the complementary DNA, TcD37, encodes a putative pn+ product 5.  Here we report the nucleotide sequence of TcD37 and the similarity of its deduced protein product to the catalytic domain of mammalian GTPase-activating proteins (GAPs); GAPs stimulate the GTPase activity of Ras (ref. 6), which are plasma membrane-bound proteins involved in the regulation of cell proliferation and differentiation 7.  These results suggest that the Drosophila TcD37 protein participates in a biochemical pathway similar to that of Ras and GAPs in mammals and yeast.  We propose that the interaction between pn and awd is due to a neomorphic mutation that enhances the ability of Awd(K-pn) nucleoside diphosphate kinase to induce a regulatory GTPase into a GTP-bound 'on' state, whereas Pn modulates the activity of this GTPase either by switching it to a GDP-bound 'off' state or by interfering with its effector function.
C1 UNIV OREGON,INST MOLEC BIOL,EUGENE,OR 97403.
   UNIV OREGON,INST NEUROSCI,EUGENE,OR 97403.
   UNIV OREGON,DEPT CHEM,EUGENE,OR 97403.
C3 University of Oregon; University of Oregon; University of Oregon
NR 35
TC 71
Z9 71
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 437
EP 440
DI 10.1038/353437a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600059
PM 1654526
DA 2026-03-10
ER

PT J
AU KULKARNI, SR
   ANDERSON, SB
   PRINCE, TA
   WOLSZCZAN, A
AF KULKARNI, SR
   ANDERSON, SB
   PRINCE, TA
   WOLSZCZAN, A
TI OLD PULSARS IN THE LOW-DENSITY GLOBULAR-CLUSTERS M13 AND M53
SO NATURE
LA English
DT Article
ID millisecond pulsars; tidal capture; evolution
AB MILLISECOND pulsars are conventionally assumed to be spun up through the actin of binary companions, although some subsequently lose their companions and appear as isolated pulsars. Such objects should therefore be more numerous in dense stellar systems. We report here the surprising discovery of two pulsars in low-density globular clusters: one is a single 10-ms pulsar (1639 + 36) in M13 (NGC6205), the other a 33-ms pulsar (1310 + 18) in a 256-day binary in M53 (NGC5025). Their ages, inferred from their luminosities and constraints on their period derivatives, seem to be approximately 10(9) years, significantly greater than previously reported ages (less-than-or-similar-to 10(8) years) of cluster pulsars1. The implied birth rate is inconsistent with the conventional two-body tidal capture model 2,3, suggesting that an alternative mechanism such as tidal capture between primordial binaries and a reservoir of (hundreds of) primordial neutron stars may dominate the production of tidal binaries in such clusters1,4. The period derivative of PSR1639 + 36 is surprisingly small, and may be corrupted by acceleration due to the mean gravitational potential of the cluster5.
C1 ARECIBO OBSERV, ARECIBO, PR 00612 USA.
C3 National Aeronautics & Space Administration (NASA)
RP KULKARNI, SR (corresponding author), CALTECH, DIV PHYS MATH & ASTRON, PASADENA, CA 91125 USA.
NR 23
TC 37
Z9 39
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 47
EP 49
DI 10.1038/349047a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100044
DA 2026-03-10
ER

PT J
AU KWON, IC
   BAE, YH
   KIM, SW
AF KWON, IC
   BAE, YH
   KIM, SW
TI ELECTRICALLY ERODIBLE POLYMER GEL FOR CONTROLLED RELEASE OF DRUGS
SO NATURE
LA English
DT Article
ID intermacromolecular complexes; sensitive polymers; phase-transition; delivery; membrane
AB NEW controlled drug-delivery systems are being explored to overcome the disadvantages of conventional dosage forms 1. For example, stimulated drug-delivery has been used to overcome the tolerance problems that occur with a constant delivery rate, to mimic the physiological pattern of hormonal concentration and to supply drugs on demand 1,2. Stimuli-sensitive polymers, which are potentially useful for pulsed drug delivery, experience changes in either their structure or their chemical properties in response to changes in environmental conditions 2. Environmental stimuli include temperature 3,4, pH 5,6, light (ultraviolet 7 or visible 8), electric field 9-12 or certain chemicals 13. Volume changes of stimuli-sensitive gel networks are particularly responsive to external stimuli, but swelling is slow to occur 14,15. As well as being useful in the controlled release of drugs, such systems also provide insight into intermolecular interactions 16. Here we report on a novel polymeric system, which rapidly changes from a solid state to solution in response to small electric currents, by disintegration of the solid polymer complex into two water-soluble polymers. We show that the modulated release of insulin, and by extension other macromolecules, can be achieved with this polymeric system.
RP KWON, IC (corresponding author), UNIV UTAH,CTR CONTROLLED CHEM DELIVERY,421 WAKARA WAY,SALT LAKE CITY,UT 84108, USA.
NR 19
TC 618
Z9 750
U1 0
U2 125
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 291
EP 293
DI 10.1038/354291a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400042
PM 1956379
DA 2026-03-10
ER

PT J
AU GODARD, R
AF GODARD, R
TI LONG-TERM-MEMORY OF INDIVIDUAL NEIGHBORS IN A MIGRATORY SONGBIRD
SO NATURE
LA English
DT Article
ID brain space; evolution; birds
AB Capabilities for long-term memory and recall of information have evolved in non-human animals primarily for special requirements such as for learning species-typical vocalizations and caching food 1-6.  Long-term memory of individual social partners has, however, not been demonstrated previously for non-human animals.  The ability to recognize individuals has important consequences for the evolution of intricate social interactions 7-11 and provides a basis for more sophisticated forms of cognition in animal societies 12,13.  Recognition of social partners has been documented for territorial songbirds, which discriminate between songs of different neighbours 14-16 as well as between the songs of strangers and neighbours 17.  Here I show that male hooded warblers (Wilsonia citrina, Parulinae) not only recognize their neighbours individually by song during the breeding season, but also retain the memory of neighbours' songs after an 8-month period during which they cease singing and migrate to Central America before they return to former breeding territories.
RP GODARD, R (corresponding author), UNIV N CAROLINA,DEPT BIOL,CHAPEL HILL,NC 27599, USA.
NR 24
TC 189
Z9 212
U1 1
U2 47
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 228
EP 229
DI 10.1038/350228a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900056
DA 2026-03-10
ER

PT J
AU BORSANI, G
   TONLORENZI, R
   SIMMLER, MC
   DANDOLO, L
   ARNAUD, D
   CAPRA, V
   GROMPE, M
   PIZZUTI, A
   MUZNY, D
   LAWRENCE, C
   WILLARD, HF
   AVNER, P
   BALLABIO, A
AF BORSANI, G
   TONLORENZI, R
   SIMMLER, MC
   DANDOLO, L
   ARNAUD, D
   CAPRA, V
   GROMPE, M
   PIZZUTI, A
   MUZNY, D
   LAWRENCE, C
   WILLARD, HF
   AVNER, P
   BALLABIO, A
TI CHARACTERIZATION OF A MURINE GENE EXPRESSED FROM THE INACTIVE X-CHROMOSOME
SO NATURE
LA English
DT Article
ID mouse; dna; mechanisms; sequences; alignment; region; family; cdna
AB IN mammals, equal dosage of gene products encoded by the X chromosome in male and female cells is achieved by X inactivation.  Although X-chromosome inactivation represents the most extensive example known of long range cis gene regulation, the mechanism by which thousands of gene on only one of a pair of identical chromosomes are turned off is poorly understood.  We have recently identified a human gene (XIST) exclusively expressed from the inactive X chromosome 1.  Here we report the isolation and characterization of its murine homologue (Xist) which localizes to the mouse X inactivation centre region and is the first murine gene found to be expressed from the inactive X chromosome.  Nucleotide sequence analysis indicates that Xist may be associated with a protein product.  The similar map positions and expression patterns for Xist in mouse and man suggest that this gene may have a role in X inactivation.
C1 BAYLOR UNIV,INST MOLEC GENET,HOUSTON,TX 77030.
   BAYLOR UNIV,DEPT CELL BIOL,HOUSTON,TX 77030.
   INST PASTEUR,UNITE GENET MOLEC MARINE,F-75724 PARIS 15,FRANCE.
   STANFORD UNIV,MED CTR,SCH MED,DEPT GENET,STANFORD,CA 94305.
C3 Baylor College of Medicine; Baylor University; Baylor University; Pasteur Network; Universite Paris Cite; Institut Pasteur Paris; Stanford University
NR 29
TC 497
Z9 571
U1 1
U2 37
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 325
EP 329
DI 10.1038/351325a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600064
PM 2034278
DA 2026-03-10
ER

PT J
AU ZHANG, YX
   STOLPER, EM
AF ZHANG, YX
   STOLPER, EM
TI WATER DIFFUSION IN A BASALTIC MELT
SO NATURE
LA English
DT Article
ID ion micro-probe; elevated-temperatures; submarine basalts; silicate melts; glasses; carbon; h2o; co2; pressures; abundance
AB WATER is the most abundant volatile component in terrestrial basalts and is a significant constituent of the gases that escape from basaltic magmas.  Knowledge of the diffusivity of water (and other volatiles) in basaltic melts is important for understanding the degassing of basaltic magma and for assessing the fractionation of volatiles during degassing.  We report here measurements of water diffusivity in a basaltic liquid.  The water concentration profiles through the samples, determined by Fourier-transform infrared spectroscopy, cannot be modelled adequately on the basis of a constant water diffusivity 1-7, but instead can be fitted by assuming that only molecular H2O is diffusing and that there is a local equilibrium between H2O molecules and OH groups 7-13.  The concentration-dependent total water diffusivities in the basaltic melt at 1,300-1,500-degrees-C are 30-50 times as large as those in rhyolitic melts 4-7, and are greater than the total CO2 diffusivity in basaltic melts, contrary to previous expectations 14.  These results suggest that diffusive fractionation would increase the ratio of water to carbon dioxide in growing bubbles relative to equilibrium partitioning, and decrease the ratio in interface melts near an advancing anhydrous phenocryst.
RP ZHANG, YX (corresponding author), CALTECH,DEPT GEOL & PLANETARY SCI,17025,PASADENA,CA 91125, USA.
NR 33
TC 161
Z9 178
U1 2
U2 35
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 306
EP 309
DI 10.1038/351306a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600056
PM 11538704
DA 2026-03-10
ER

PT J
AU MCDONNELL, TJ
   KORSMEYER, SJ
AF MCDONNELL, TJ
   KORSMEYER, SJ
TI PROGRESSION FROM LYMPHOID HYPERPLASIA TO HIGH-GRADE MALIGNANT-LYMPHOMA IN MICE TRANSGENIC FOR THE T(14, 18)
SO NATURE
LA English
DT Article
ID c-myc oncogene; chromosome translocations; nucleotide-sequence; follicular lymphoma; burkitt-lymphoma; cell survival; gene; region; locus; activation
AB FOLLICULAR lymphoma, the most common human lymphoma, characteristically has a t(14; 18) interchromosomal translocation 1,2. Its is typically an indolent disease comprised of small resting B cells, but frequently develops into a high-grade lymphoma 3. The t(14; 18) translocates the Bcl-2 gene, generating a deregulated Bcl-2-immunoglobulin fusion gene 4-8. Bcl-2 is a novel inner mitochondrial membrane protein 9 that extends the survival of certain cells by blocking programmed cell death 9-11. To determine the oncogenic potential of the t(14; 18) translocation, we produced transgenic mice bearing a Bcl-2-immunoglobulin minigene that structurally mimicked the t(14; 18) (ref. 12). An indolent follicular hyperplasia in these transgenic mice progressed to a malignant diffuse large-cell lymphoma. The long latency, progression from polyclonal to monoclonal disease, and histological conversion, are all suggestive of secondary changes. Half of the immunoblastic high-grade lymphomas had a rearranged c-myc gene. Our transgenic mice provide an animal model for tumour progression in t(14; 18) lymphoma and show that prolonged B-cell life increases tumour incidence.
C1 WASHINGTON UNIV, SCH MED, DEPT MED, ST LOUIS, MO 63110 USA.
   WASHINGTON UNIV, SCH MED, DEPT MOLEC MICROBIOL, ST LOUIS, MO 63110 USA.
   WASHINGTON UNIV, SCH MED, DEPT PATHOL, ST LOUIS, MO 63110 USA.
C3 Washington University (WUSTL); Washington University (WUSTL); Washington University (WUSTL)
RP MCDONNELL, TJ (corresponding author), WASHINGTON UNIV, SCH MED, HOWARD HUGHES MED INST, 660 S EUCLID, ST LOUIS, MO 63110 USA.
NR 28
TC 814
Z9 879
U1 0
U2 13
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 254
EP 256
DI 10.1038/349254a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900061
PM 1987477
DA 2026-03-10
ER

PT J
AU MCMAHON, PB
   CHAPELLE, FH
AF MCMAHON, PB
   CHAPELLE, FH
TI MICROBIAL-PRODUCTION OF ORGANIC-ACIDS IN AQUITARD SEDIMENTS AND ITS ROLE IN AQUIFER GEOCHEMISTRY
SO NATURE
LA English
DT Article
ID groundwater; subsurface; bacteria; carbon; waters; co2
AB MICROBIAL activity in aquifers plays an important part in the chemical evolution of ground water 1-5.  The most important terminal electron-accepting microbial processes in deeply buried anaerobic aquifers are iron reduction, sulphate reduction and methanogenesis 5-8, each of which requires simple organic compounds or hydrogen (H2) as electron donors.  Until now, the source of these compounds was unknown because the concentrations of dissolved 1 organic carbon and sedimentary organic carbon in aquifers are extremely low 9-11.  Here we show that rates of microbial fermentation exceed rates of respiration in organic-rich aquitards (low-permeability sediments stratigraphically adjacent to higher-permeability aquifer sediments), resulting in a net accumulation of simple organic acids in pore waters.  In aquifers, however, respiration outpaces fermentation, resulting in a net consumption of organic acids.  The concentration gradient that develops in response to these two processes drives a net diffusive flux of organic acids from aquitards to aquifers.  Diffusion calculations demonstrate that rates of organic acid transport are sufficient to account for observed rates of microbial respiration in aquifers.  This overall process effectively links the large pool of sedimentary organic carbon in aquitards to microbial respiration in aquifers, and is a principal mechanism driving groundwater chemistry changes in aquifers.
RP MCMAHON, PB (corresponding author), US GEOL SURVEY,STEPHENSON CTR,SUITE 129,720 GRACERN RD,COLUMBIA,SC 29210, USA.
NR 25
TC 216
Z9 242
U1 1
U2 57
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 233
EP 235
DI 10.1038/349233a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900053
DA 2026-03-10
ER

PT J
AU LACERDA, AE
   KIM, HS
   RUTH, P
   PEREZREYES, E
   FLOCKERZI, V
   HOFMANN, F
   BIRNBAUMER, L
   BROWN, AM
AF LACERDA, AE
   KIM, HS
   RUTH, P
   PEREZREYES, E
   FLOCKERZI, V
   HOFMANN, F
   BIRNBAUMER, L
   BROWN, AM
TI NORMALIZATION OF CURRENT KINETICS BY INTERACTION BETWEEN THE ALPHA-1-SUBUNIT AND BETA-SUBUNIT OF THE SKELETAL-MUSCLE DIHYDROPYRIDINE-SENSITIVE CA2+ CHANNEL
SO NATURE
LA English
DT Article
ID calcium-channel; functional expression; molecular-cloning; gamma-subunit; ca-2+ channel; receptor; sequence; protein; cells; cdna
AB PURIFICATION of skeletal muscle dihydropyridine binding sites has enabled protein complexes to be isolated from which Ca2+ currents have been reconstituted. Complementary DNAs encoding the five subunits of the dihydropyridine receptor, alpha-1, beta, gamma, alpha-2 and delta (ref. 1), have been cloned 2-6 and it is now recognized that alpha-2 and delta are derived from a common precursor 7,8.  The alpha-1 subunit can itself produce Ca2+ currents, as was demonstrated using mouse L cells lacking alpha-2-delta (refs 9, 10), beta (ref. 10) and gamma (our unpublished results). In L cells, stable expression of skeletal muscle-alpha-1 alone was sufficient to generate voltage-sensitive, high-threshold L-type Ca2+ channel currents which were dihydropyridine-sensitive and blocked by Cd2+, but the activation kinetics were about 100 times slower than expected for skeletal muscle Ca2+ channel currents. This could have been due to the cell type in which alpha-1 was being expressed or to the lack of a regulatory component particularly one of the subunits that copurifies with alpha-1. We show here that coexpression of skeletal muscle-beta with skeletal muscle-alpha-1 generates cell lines expressing Ca2+ channel currents with normal activation kinetics as evidence for the participation of the dihydropyridine-receptor beta-subunits in the generation of skeletal muscle Ca2+ channel currents.
C1 BAYLOR UNIV,DEPT CELL BIOL,HOUSTON,TX 77030.
   BAYLOR UNIV,DIV NEUROSCI,HOUSTON,TX 77030.
   UNIV SAARLAND,FAC MED,INST PHYSIOL CHEM,W-6650 HOMBURG,GERMANY.
C3 Baylor University; Baylor University; Saarland University
RP LACERDA, AE (corresponding author), BAYLOR UNIV,DEPT MOLEC PHYSIOL & BIOPHYS,HOUSTON,TX 77030, USA.
NR 21
TC 269
Z9 305
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 527
EP 530
DI 10.1038/352527a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600062
PM 1650913
DA 2026-03-10
ER

PT J
AU TURK, E
   ZABEL, B
   MUNDLOS, S
   DYER, J
   WRIGHT, EM
AF TURK, E
   ZABEL, B
   MUNDLOS, S
   DYER, J
   WRIGHT, EM
TI GLUCOSE GALACTOSE MALABSORPTION CAUSED BY A DEFECT IN THE NA+/GLUCOSE COTRANSPORTER
SO NATURE
LA English
DT Article
ID human intestinal na+/glucose; polymerase chain-reaction; single-stranded-dna; transporter; expression; numbers; cells; cdna
AB GLUCOSE/galactose malabsorption (GGM) is an autosomal recessive disease manifesting within the first weeks of life and characterized by a selective failure to absorb dietary glucose and galactose from the intestine 1.  The consequent severe diarrhoea and dehydration are usually fatal unless these sugars are eliminated from the diet. Intestinal biopsies of GGM patients have revealed a specific defect in Na+-dependent absorption of glucose in the brush border 2-4.  Normal glucose absorption is mediated by the Na+/glucose cotransporter in the brush border membrane of the intestinal epithelium 5.  Cellular influx is driven by the transmembrane Na+ electrochemical potential gradient; thereafter the sugar moves to the blood across the basolateral membrane via the facilitated glucose carrier.  We have previously cloned and sequenced a Na+/glucose cotransporter from normal human ileum 6 and shown that this gene, SGLT1, resides on the distal q arm of chromosome 22 7.  We have now amplified SGLT1 complementary DNA and genomic DNA from members of a family affected with GGM by the polymerase chain reaction 8.  Sequence analysis of the amplified products has revealed a single missense mutation in SGLT1 which cosegregates with the GGM phenotype and results in a complete loss of Na+-dependent glucose transport in Xenopus oocytes injected with this complementary RNA.
C1 UNIV MAINZ,DEPT PEDIAT,W-6500 MAINZ,GERMANY.
C3 Johannes Gutenberg University of Mainz
RP TURK, E (corresponding author), UNIV CALIF LOS ANGELES,SCH MED,DEPT PHYSIOL,LOS ANGELES,CA 90024, USA.
NR 17
TC 316
Z9 354
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 354
EP 356
DI 10.1038/350354a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800097
PM 2008213
DA 2026-03-10
ER

PT J
AU CACHIER, H
   DUCRET, J
AF CACHIER, H
   DUCRET, J
TI INFLUENCE OF BIOMASS BURNING ON EQUATORIAL AFRICAN RAINS
SO NATURE
LA English
DT Article
ID atmosphere; tropics; carbon
AB BIOMASS burning affects the African continent all year round 1-4. In the dry season there are widespread savannah fires, and there are always some domestic and agricultural fires. Here we present measurement of particulate black carbon, which is an unambiguous indicator of combustion, in rain waters collected at a remote site in the Northern Congo. We find that the rains contain pollutants from biomass burning, and are particularly affected during the Northern Hemisphere dry season. Our results show that biomass-burning smoke particles may act as cloud condensation nuclei, and might thereby play a part in cloud formation and hence precipitation in the tropics 3.
RP CACHIER, H (corresponding author), CEA,CNRS,CTR FAIBLES RADIOACT,AVE TERRASSE,F-91198 GIF SUR YVETTE,FRANCE.
NR 18
TC 46
Z9 49
U1 0
U2 33
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 228
EP 230
DI 10.1038/352228a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500061
DA 2026-03-10
ER

PT J
AU BECKER, B
   KROMER, B
   TRIMBORN, P
AF BECKER, B
   KROMER, B
   TRIMBORN, P
TI A STABLE-ISOTOPE TREE-RING TIMESCALE OF THE LATE GLACIAL HOLOCENE BOUNDARY
SO NATURE
LA English
DT Article
ID c-14; calibration; hydrogen; ratios; scale
AB LATE Glacial and Holocene tree-ring chronologies, like deep-sea sediments or polar ice cores, contain information about past environments. Changes in tree-ring growth rates can be related to past climate anomalies and changes in the isotope composition of tree-ring cellulose reflect changes in the composition of the atmosphere and the hydrosphere. We have established a 9,928-year absolutely dated dendrochronological record of Holocene oak (Quercus robur, Quercus petraea)-and a 1,604-year floating Late Glacial and Early Holocene chronology of pine (Pinus sylvestris) from subfossil tree remnants deposited in alluvial terraces of south central European rivers. The pine sequence provides records of dendro-dated  C-14, C-13 and H-2 patterns for the late Younger Dryas and the entire Preboreal (10,100-9,000 yr BP). Through the use of dendrochronology, radiocarbon age calibration and stable isotope analysis, we suggest that the Late Glacial/Holocene transition may be identified and dated by C-13 and H-2 tree-ring chronologies.
C1 UNIV HEIDELBERG,INST UMWELTPHYS,W-6900 HEIDELBERG,GERMANY.
   GESELL STRAHLEN & UMWELTFORSCH MBH,INST HYDROL,W-8042 NEUHERBERG,GERMANY.
C3 Ruprecht Karls University Heidelberg
RP BECKER, B (corresponding author), UNIV STUTTGART,INST BOT,HOHENHEIM 210,W-7000 STUTTGART 80,GERMANY.
NR 24
TC 142
Z9 147
U1 0
U2 34
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 647
EP 649
DI 10.1038/353647a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200065
DA 2026-03-10
ER

PT J
AU SETO, E
   SHI, Y
   SHENK, T
AF SETO, E
   SHI, Y
   SHENK, T
TI YY1 IS AN INITIATOR SEQUENCE-BINDING PROTEIN THAT DIRECTS AND ACTIVATES TRANSCRIPTION INVITRO
SO NATURE
LA English
DT Article
ID mammary-tumor virus; major late promoter; long-terminal repeat; rna polymerase-ii; control region; gene; box; tata; identification; purification
AB REGULATION of eukaryotic messenger RNA transcription is governed by DNA sequence elements that serve as binding sites for sequence-specific transcription factors 1-3.  These include upstream and downstream promoter-proximal elements, enhancers, repressors, and silencers, which modulate the rate of specific initiation by RNA polymerase II. In addition, the promoter-proximal region between -45 and +30 (relative to the start of initiation) contains two highly conserved motifs, the TATA sequence at around -30 and CA at +1 (ref. 4). Although the TATA element-binding factor TFIID has been purified and cloned from several organisms and has provided invaluable insight into the process of transcription initiation and its regulation, little is known about factors that interact at the +1 region. We have recently shown that the adeno-associated virus type 2 P5 promoter +1 region (P5 + 1 element) binds transcription factor YY1 (ref. 5). We report here that this sequence is necessary and sufficient for accurate basal transcription. Further, partially purified YY1 can restore basal level transcription from a P5 + 1 element in a HeLa extract depleted for YY1 or a Drosophila embryo extract devoid of YY1 activity, whereas a YY1-specific antibody can block the reactivation. Finally, using electrophoretic mobility shift assay, we have identified YY1-related factors that bind to two other transcription initiators in cellular genes.
C1 PRINCETON UNIV,DEPT MOLEC BIOL,HOWARD HUGHES MED INST,PRINCETON,NJ 08544.
C3 Princeton University; Howard Hughes Medical Institute
NR 34
TC 414
Z9 450
U1 2
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 241
EP 245
DI 10.1038/354241a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800053
PM 1720509
DA 2026-03-10
ER

PT J
AU REVAH, F
   BERTRAND, D
   GALZI, JL
   DEVILLERSTHIERY, A
   MULLE, C
   HUSSY, N
   BERTRAND, S
   BALLIVET, M
   CHANGEUX, JP
AF REVAH, F
   BERTRAND, D
   GALZI, JL
   DEVILLERSTHIERY, A
   MULLE, C
   HUSSY, N
   BERTRAND, S
   BALLIVET, M
   CHANGEUX, JP
TI MUTATIONS IN THE CHANNEL DOMAIN ALTER DESENSITIZATION OF A NEURONAL NICOTINIC RECEPTOR
SO NATURE
LA English
DT Article
ID affinity binding-site; acetylcholine-receptor; h-3 chlorpromazine; ion channel; delta-subunit; noncompetitive blockers; activated channels; amino-acids; superfamily; transport
AB A VARIETY of ligand-gated ion channels undergo a fast activation process after the rapid application of agonist and also a slower transition towards desensitized or inactivated closed channel states when exposure to agonist is prolonged 1-5.  Desensitization involves at least two distinct closed states in the acetylcholine receptor, each with an affinity for agonists higher than those of the resting or active conformations 1-5. Here we investigate how structural elements could be involved in the desensitization of the acetylcholine-gated ion channel from the chick brain alpha-bungarotoxin sensitive homo-oligomeric alpha-7 receptor 6,7, using site-directed mutagenesis and expression in Xenopus oocytes. Mutations of the highly conserved leucine 247 residue 8,9 from the uncharged MII segment of alpha-7 suppress inhibition by the open-channel blocker QX-222 (ref. 10), indicating that this residue, like others from MII (refs 11-22), faces the lumen of the channel. But, unexpectedly, the same mutations decrease the rate of desensitization of the response, increase the apparent affinity for acetylcholine and abolish current rectification. Moreover, unlike wild-type alpha-7, which has channels with a single conductance level, the leucine-to-threonine mutant has an additional conducting state active at low acetylcholine concentrations. It is possible that mutation of Leu 247 renders conductive one of the high-affinity desensitized states of the receptor.
C1 UNIV GENEVA,DEPT BIOCHIM,CH-1211 GENEVA 4,SWITZERLAND.
   UNIV GENEVA,MED CTR,FAC MED,DEPT PHYSIOL,CH-1211 GENEVA 4,SWITZERLAND.
C3 University of Geneva; University of Geneva
RP REVAH, F (corresponding author), INST PASTEUR,CNRS,UNITE RECH ASSOCIEE D1284,25 RUE DR ROUX,F-75724 PARIS 15,FRANCE.
NR 25
TC 474
Z9 526
U1 1
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 846
EP 849
DI 10.1038/353846a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200060
PM 1719423
DA 2026-03-10
ER

PT J
AU GIBBONS, IR
   GIBBONS, BH
   MOCZ, G
   ASAI, DJ
AF GIBBONS, IR
   GIBBONS, BH
   MOCZ, G
   ASAI, DJ
TI MULTIPLE NUCLEOTIDE-BINDING SITES IN THE SEQUENCE OF DYNEIN BETA-HEAVY CHAIN
SO NATURE
LA English
DT Article
ID sea-urchin sperm; outer arm dynein; photosensitized cleavage; molecular-cloning; flagella; myosin; alpha; proteins; kinesin; atp
AB AXONEMAL dyneins have two or three globular heads joined by flexible tails to a common base, with each head/tail unit consisting of a single heavy-chain polypeptide of relative molecular mass > 400,000. The sizes of the components have been deduced by electron microscopy 1-3 . The isolated-beta heavy chain of sea urchin sperm flagella, which is immunologically identical to that of the embryo cilia (data not shown; ref. 4), is of particular interest as it retains the capability for microtubule translocation in vitro 5,6. Limited proteolysis of the beta-heavy chain divides it into two fragments, A and B, which sediment separately at 12S and 6S, and possibly correspond to the head and tail domains of the molecule 7. Dynein ATPase is the energy-transducing enzyme that generates the sliding movement between tubules that underlies the beating of cilia and flagella of eukaryotes, and possibly also other large intracellular movements 8,9. Here we report that the deduced amino-acid sequence of the beta-heavy chain of axonemal dynein from embryos of the sea urchin Tripneustes gratilla has 4,466 residues and contains the consensus motifs for five nucleotide-binding sites. The probable hydrolytic ATP-binding site can be identified by its location close to or at the V1 site of vanadate-mediated photocleavage 10. The general features of the map of photocleavage and proteolytic peptides reported earlier have been confirmed, except that the map's polarity is reversed. The predicted secondary structure of the beta-heavy chain consists of an alpha/beta-type pattern along its whole length. The two longest regions of potential alpha helix, with unbroken heptad hydrophobic repeats 120 and 50 amino acids long, may be of functional importance. But dynein does not seem to contain an extended coiled-coil tail domain.
C1 PURDUE UNIV,DEPT BIOL SCI,W LAFAYETTE,IN 47907.
C3 Purdue University System; Purdue University
RP GIBBONS, IR (corresponding author), UNIV HAWAII,PACIFIC BIOMED RES CTR,HONOLULU,HI 96822, USA.
NR 34
TC 226
Z9 241
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 640
EP 643
DI 10.1038/352640a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100062
PM 1830927
DA 2026-03-10
ER

PT J
AU JABLON, C
AF JABLON, C
TI ELF AQUITAINE - RESEARCH-AND-DEVELOPMENT IN ONE OF EUROPE LEADING INDUSTRIAL COMPANIES
SO NATURE
LA English
DT Article
RP JABLON, C (corresponding author), SOC NATL ELF AQUITAINE,TOUR ELF,F-92078 PARIS,FRANCE.
NR 0
TC 0
Z9 0
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 2
EP 3
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100002
DA 2026-03-10
ER

PT J
AU LARKMAN, A
   STRATFORD, K
   JACK, J
AF LARKMAN, A
   STRATFORD, K
   JACK, J
TI QUANTAL ANALYSIS OF EXCITATORY SYNAPTIC ACTION AND DEPRESSION IN HIPPOCAMPAL SLICES
SO NATURE
LA English
DT Article
ID long-term potentiation; transmission; release; glutamate; synapses; neurons; calcium
AB QUANTAL analysis can provide a quantitative description of important aspects of chemical synaptic transmission and its modification 1-3.  The technique has recently been applied to excitatory synapses within the hippocampus 4-10, especially the form of synaptic plasticity known as long-term potentiation 11-13.  However, these attempts have met with only limited success, in that the individual quantal amplitudes making up the synaptic response generally could not be resolved.  Here we have paid attention to the possible instability of the quantal fluctuation pattern over time.  We were able to resolve individual quantal component amplitudes for a high proportion of the experiments, and so demonstrate the quantal nature of excitatory transmission in the CA1 region of the hippocampus.  Mean quantal amplitudes for individual excitatory postsynaptic potentials were 84-197-mu-V, with a mean of 131 +/- 29-mu-V.  For periods during which the fluctuation pattern was stable, the variance associated with individual quantal amplitudes was low.  We have also used quantal analysis to show that synaptic depression following prolonged stimulation at these synapses is primarily a presynaptic phenomenon.
RP LARKMAN, A (corresponding author), UNIV OXFORD,PHYSIOL LAB,PARKS RD,OXFORD OX1 3PT,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 34
TC 169
Z9 178
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 344
EP 347
DI 10.1038/350344a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800094
PM 1848922
DA 2026-03-10
ER

PT J
AU NELSON, BK
   MACLEOD, GK
   WARD, PD
AF NELSON, BK
   MACLEOD, GK
   WARD, PD
TI RAPID CHANGE IN STRONTIUM ISOTOPIC COMPOSITION OF SEA-WATER BEFORE THE CRETACEOUS TERTIARY BOUNDARY
SO NATURE
LA English
DT Article
ID evolution; seawater; sr; ratio; diagenesis; site
AB A CRITICAL aspect of the debate over the origin of the chemical, biological and climatological perturbations that characterize the Cretaceous/Tertiary boundary (K/T boundary) is the timescale and detailed pattern of the extinctions and geochemical changes.  Whether the development of the anomalies was catastrophic (over tens to hundreds of years) or more gradual (10(3) to 10(6) years), whether the anomalies occur exactly at the boundary or precede it, and whether the chemical and biological signatures represent one event or can be resolved into several discrete events, are issues fundamental to identifying the cause of the marked changes.  To determine the timing and rate of change of strontium isotope evolution of sea water during the five million years preceding the K/T boundary, we analysed foraminifera from an exceptionally thick, palaeontologically well-characterized marine K/T section exposed at Bidart, southwest France.  We found a rapid increase in Sr-87/Sr-86 of ocean water 1.5 to 2.3 Myr before the boundary.  The increase may be explained by a 10% increase in continental strontium flux to the oceans over a period of about 1 Myr.
RP NELSON, BK (corresponding author), UNIV WASHINGTON,DEPT GEOL SCI,AJ-20,SEATTLE,WA 98195, USA.
NR 21
TC 51
Z9 56
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 644
EP 647
DI 10.1038/351644a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200063
DA 2026-03-10
ER

PT J
AU MARTINEZ, CK
   MONACO, JJ
AF MARTINEZ, CK
   MONACO, JJ
TI HOMOLOGY OF PROTEASOME SUBUNITS TO A MAJOR HISTOCOMPATIBILITY COMPLEX-LINKED LMP GENE
SO NATURE
LA English
DT Article
ID rat hepatoma-cells; cdna cloning; molecular-cloning; crossing-over; proteinase; mhc; antigens; liver
AB THE ClaSS II region of the major histocompatibility complex (MHC) contains genes encoding at least two subunits of a large, intracellular protein complex (the low molecular mass polypeptide, or LMP, complex) 1-3. This complex is biochemically similar to the proteasome, an abundant and well conserved protein complex having multiple proteolytic activities. Here we report the isolation of a complementary DNA corresponding to one of the subunits of the LMP complex, LMP-2. The protein predicted from this cDNA sequence closely matches the amino-terminal peptide sequence of a rat proteasome subunit, confirming that the proteasome and the LMP complex share polypeptide subunits. The LMP-2 gene is tightly linked to HAM1, a gene thought to be required for translocating peptide fragments of endogenous antigens into the endoplasmic reticulum for association with MHC class I molecules 4. These observations suggest that the LMP complex may be responsible for generating peptides from cytoplasmic antigen during antigen processing.
C1 VIRGINIA COMMONWEALTH UNIV,MED COLL VIRGINIA,DEPT PATHOL,RICHMOND,VA 23298.
C3 Virginia Commonwealth University
RP MARTINEZ, CK (corresponding author), VIRGINIA COMMONWEALTH UNIV,MED COLL VIRGINIA,DEPT MICROBIOL & IMMUNOL,RICHMOND,VA 23298, USA.
NR 16
TC 259
Z9 279
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 664
EP 667
DI 10.1038/353664a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200072
PM 1681432
DA 2026-03-10
ER

PT J
AU BARBER, BP
   PUTTERMAN, SJ
AF BARBER, BP
   PUTTERMAN, SJ
TI OBSERVATION OF SYNCHRONOUS PICOSECOND SONOLUMINESCENCE
SO NATURE
LA English
DT Article
ID stable cavitation
AB SONOLUMINESCENCE 1-13 is a non-equilibrium phenomenon in which the energy in a sound wave becomes highly concentrated so as to generate flashes of light in a liquid. We show here that these flashes, which comprise over 10(5) photons, are too fast to be resolved by the fastest photomultiplier tubes available. Furthermore, when sonoluminescence is driven by a resonant sound field, the bursts can occur in a continuously repeating, regular fashion. These precise 'clock-like' emissions can continue for hours at drive frequencies ranging from audible to ultrasonic. These bursts represent an amplification of energy by eleven orders of magnitude.
RP BARBER, BP (corresponding author), UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024, USA.
NR 22
TC 406
Z9 461
U1 0
U2 60
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 318
EP 320
DI 10.1038/352318a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900064
DA 2026-03-10
ER

PT J
AU RAMACHANDRAN, VS
   GREGORY, RL
AF RAMACHANDRAN, VS
   GREGORY, RL
TI PERCEPTUAL FILLING IN OF ARTIFICIALLY INDUCED SCOTOMAS IN HUMAN VISION
SO NATURE
LA English
DT Article
ID apparent motion; visual areas; color; contours; form
AB PATIENTS with scotomas or blind-spots in their visual field 1-5 resulting from damage to the visual pathways often report that the pattern from the rest of the visual field 'fills in' to occupy the scotoma.  Here we describe a novel technique for generating an artificial perceptual scotoma which enabled us to study the spatial and temporal characteristics of this filling-in process.  A homogeneous grey square subtending 1.5-degrees was displayed against a background of twinkling two-dimensional noise of equal mean luminance (Fig. 1).  On steady eccentric fixation for 10 s the square vanished and was filled in by the twinkling noise from the surround.  Using this display we found that 'filling in' is an active visual process that probably involves creating an actual neural representation of the surround rather than merely ignoring the absence of information from the scotoma; filling in can occur separately for colour and texture, suggesting separate mechanisms; the filling-in process does not completely suppress information from the scotoma, even after an image has faded completely from consciousness it can nevertheless contribute to motion perception; and the process can be strongly influenced by illusory contours.
C1 UNIV BRISTOL,DEPT PSYCHOL,BRISTOL BS8 1TH,AVON,ENGLAND.
C3 University of Bristol
RP RAMACHANDRAN, VS (corresponding author), UNIV CALIF SAN DIEGO,DEPT PSYCHOL 0109,LA JOLLA,CA 92092, USA.
NR 31
TC 357
Z9 387
U1 0
U2 29
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 699
EP 702
DI 10.1038/350699a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000058
PM 2023631
DA 2026-03-10
ER

PT J
AU ROBERTSON, DS
   CARTER, WE
   DILLINGER, WH
AF ROBERTSON, DS
   CARTER, WE
   DILLINGER, WH
TI NEW MEASUREMENT OF SOLAR GRAVITATIONAL DEFLECTION OF RADIO SIGNALS USING VLBI
SO NATURE
LA English
DT Article
ID earths surface; interferometry; gravity; geodesy; 3c-273
AB RADIO observations using very-long-baseline interferometry (VLBI) can measure the deflection of electromagnetic radiation by the Sun's gravitational field with an accuracy of better than 1 milliarcsecond, and can thus be used to test General Relativity.  For an object at an angle-alpha from the centre of the Sun, the expected deflection is 1 (1 + gamma) (M(s)/r(e))((1 + cos-alpha)/(1 - cos-alpha)) 1/2, where M(s) is the mass of the Sun in geometrized units 2 (1.477 x 10(5) cm), r(e) is the distance from the Earth to the Sun in cm, and gamma is a parameter whose value is 1 if General Relativity is correct but which takes on different values in other theories of gravity.  For gamma = 1, the deflection is 1,750 mas at the Sun's limb, 4 mas at alpha = 90-degrees and 0 at alpha = 180-degrees.  Our analysis of ten years of VLBI data, including observations of objects in the range 2.5-degrees < alpha < 178-degrees, yields an estimate gamma = 1.0002 with a formal standard error of 0.00096 and an estimated standard error of 0.002.  This determination is comparable in accuracy and in good agreement with the determination from Mars-Viking time-delay measurements 3.
RP ROBERTSON, DS (corresponding author), NOAA,OFF OCEAN & EARTH SCI,GEOSCI LAB,ROCKVILLE,MD 20852, USA.
NR 26
TC 90
Z9 93
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 768
EP 770
DI 10.1038/349768a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600047
DA 2026-03-10
ER

PT J
AU BIX, M
   LIAO, NS
   ZIJLSTRA, M
   LORING, J
   JAENISCH, R
   RAULET, D
AF BIX, M
   LIAO, NS
   ZIJLSTRA, M
   LORING, J
   JAENISCH, R
   RAULET, D
TI REJECTION OF CLASS-I MHC-DEFICIENT HEMATOPOIETIC-CELLS BY IRRADIATED MHC-MATCHED MICE
SO NATURE
LA English
DT Article
ID bone-marrow allografts; natural-killer cells; embryonic stem-cells; graft-rejection; t-cells; histocompatibility antigens; homologous recombination; expression; susceptibility; differentiation
AB IRRADIATED MHC-heterozygous mice often reject bone marrow cells transplanted from one of the homozygous parental strains, a phenomenon ('hybrid resistance') that appears to violate the laws of transplantation 1,2.  Rejection of parental and allogeneic marrow cells also differs from conventional T cell-mediated rejection mechanisms as it is effected by NK1.1+ cells 3-5.  To account for the unusual specificity of bone marrow rejection, it has been proposed that NK1.1+ cells destroy marrow cells that fail to express the full complement of self MHC class I (MHC-I) molecules 5.  We show here that NK1.1+ cells in normal mice reject haemopoietic transplants from mice that are deficient for normal cell-surface MHC-I expression because of a targeted mutation in the beta-2-microglobulin gene 6-9.  These findings demonstrate that deficient expression of MHC-I molecules renders marrow cells susceptible to rejection.
C1 MIT,CTR CANC RES,CAMBRIDGE,MA 02139.
   MIT,DEPT BIOL,CAMBRIDGE,MA 02139.
   MIT,DEPT BIOL,CAMBRIDGE,MA 02142.
   WHITEHEAD INST BIOMED RES,CAMBRIDGE,MA 02142.
C3 Massachusetts Institute of Technology (MIT); Massachusetts Institute of Technology (MIT); Massachusetts Institute of Technology (MIT); Massachusetts Institute of Technology (MIT); Whitehead Institute
NR 27
TC 389
Z9 465
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 329
EP 331
DI 10.1038/349329a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100052
PM 1987491
DA 2026-03-10
ER

PT J
AU LOWDER, DM
   MILLER, T
   PRICE, PB
   WESTPHAL, A
   BARWICK, SW
   HALZEN, F
   MORSE, R
AF LOWDER, DM
   MILLER, T
   PRICE, PB
   WESTPHAL, A
   BARWICK, SW
   HALZEN, F
   MORSE, R
TI OBSERVATION OF MUONS USING THE POLAR ICE CAP AS A CERENKOV DETECTOR
SO NATURE
LA English
DT Article
AB DETECTION of the small flux of extraterrestrial neutrinos expected at energies above 1 TeV, and identification of their astrophysical point sources, will require neutrino telescopes with effective areas measured in square kilometres-much larger than detectors now existing 1-3.  Such a device can be built only by using some naturally occurring detecting medium of enormous extent:  deep Antarctic ice is a strong candidate.  A neutrino telescope could be constructed by drilling holes in the ice with hot water into which photomultiplier tubes could be placed to a depth of 1 km.  Neutrinos would be recorded, as in underground neutrino detectors using water as the medium, by the observation of Cerenkov radiation from secondary muons. We have begun the AMANDA (Antarctic Muon and Neutrino Detector Array) project to test this idea, and here we describe a pilot experiment using photomultiplier tubes placed into Arctic ice in Greenland.  Cerenkov radiation from muons was detected, and a comparison of count rate with the expected muon flux indicates that the ice is very transparent, with an absorption length greater than 18 m.  Our results suggest that a full-scale Antarctic ice detector is technically quite feasible.
C1 UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717.
   UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706.
C3 University of California System; University of California Irvine; University of Wisconsin System; University of Wisconsin Madison
RP LOWDER, DM (corresponding author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA.
NR 11
TC 26
Z9 27
U1 1
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 331
EP 333
DI 10.1038/353331a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400051
DA 2026-03-10
ER

PT J
AU TURELLI, M
   HOFFMANN, AA
AF TURELLI, M
   HOFFMANN, AA
TI RAPID SPREAD OF AN INHERITED INCOMPATIBILITY FACTOR IN CALIFORNIA DROSOPHILA
SO NATURE
LA English
DT Article
ID long-distance migration; cytoplasmic incompatibility; unidirectional incompatibility; reproductive incompatibility; natural-populations; mitochondrial-dna; gene flow; simulans; melanogaster; polymorphism
AB IN Drosophila simulans in California, an inherited cytoplasmic incompatibility factor reduces egg hatch when infected males mate with uninfected females 1-7. The infection is spreading at a rate of more than 100 km per year; populations in which the infection was rare have become almost completely infected within three years. Analyses of the spread using estimates of selection in the field suggest dispersal distances far higher than those found by direct observation of flies. Hence, occasional long-distance dispersal, possibly coupled with local extinction and recolonization, may be important to the dynamics. Incompatibility factors that can readily spread through natural populations may be useful for population manipulation and important as a post-mating isolating mechanism.
C1 UNIV CALIF DAVIS, CTR POPULAT BIOL, DAVIS, CA 95616 USA.
   LA TROBE UNIV, DEPT GENET & HUMAN VARIAT, BUNDOORA, VIC 1083, AUSTRALIA.
C3 University of California System; University of California Davis; La Trobe University
RP TURELLI, M (corresponding author), UNIV CALIF DAVIS, DEPT GENET, DAVIS, CA 95616 USA.
NR 29
TC 536
Z9 586
U1 3
U2 58
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 440
EP 442
DI 10.1038/353440a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600060
PM 1896086
DA 2026-03-10
ER

PT J
AU RUBIN, EM
   KRAUSS, RM
   SPANGLER, EA
   VERSTUYFT, JG
   CLIFT, SM
AF RUBIN, EM
   KRAUSS, RM
   SPANGLER, EA
   VERSTUYFT, JG
   CLIFT, SM
TI INHIBITION OF EARLY ATHEROGENESIS IN TRANSGENIC MICE BY HUMAN APOLIPOPROTEIN-A-I
SO NATURE
LA English
DT Article
ID high-density-lipoprotein; determining atherosclerosis susceptibility; cholesterol; gene; pathogenesis; disease; mouse
AB EPIDEMIOLOGICAL surveys have identified a strong inverse relationship between the amount in the plasma of high density lipoproteins (HDL), apolipoprotein AI (ApoA-I), the major protein component of HDL, and the risk for atherosclerosis in humans 1,2. It is not known if this relationship arises from a direct antiatherogenic effect of these plasma components or if it is the result of other factors also associated with increases in ApoA-I and HDL levels. Because some strains of mice are susceptible to diet-induced formation of preatherosclerotic fatty streak lesions, and because of available techniques for the genetic manipulation of this organism, the murine system offers a unique setting in which to investigate the process of early atherogenesis. To test the hypothesis that induction of a high plasma concentration of ApoA-I and HDL would inhibit this process, we studied the effects of atherogenic diets on transgenic mice expressing high amounts of human ApoA-I. We report that transgenic mice with high plasma ApoA-I and HDL levels were significantly protected from the development of fatty streak lesions.
C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720.
C3 United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; University of California System; University of California Berkeley
RP RUBIN, EM (corresponding author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV RES MED & RADIAT BIOPHYS,BERKELEY,CA 94720, USA.
NR 23
TC 879
Z9 981
U1 0
U2 30
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 265
EP 267
DI 10.1038/353265a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400062
PM 1910153
DA 2026-03-10
ER

PT J
AU MUKHIN, L
   DOLNIKOV, G
   EVLANOV, E
   FOMENKOVA, M
   PRILUTSKY, O
   SAGDEEV, R
AF MUKHIN, L
   DOLNIKOV, G
   EVLANOV, E
   FOMENKOVA, M
   PRILUTSKY, O
   SAGDEEV, R
TI REEVALUATION OF THE CHEMISTRY OF DUST GRAINS IN THE COMA OF COMET HALLEY
SO NATURE
LA English
DT Article
ID particles; impact
AB THE bulk chemical composition of the dust grains in the coma of comet Halley has been determined 1-11 by examination of data from the PUMA 1 and 2 and PIA mass spectrometers on the Vega and Giotto missions. Although the bulk elemental composition of rock-forming elements (that is, excluding C, H, N and O) seemed to be close to solar (that is, similar to CI carbonaceous chondrites), the ion ratios of some of these elements, such as Mg+/Si+ and Fe+/Si+, are rather different from those in CI chondrites.  There has not been, however, a satisfactory investigation of the chemical composition of individual grains as a function of their mass.  Here we re-evaluate the PUMA 1 and 2 data to perform such an analysis.  We find that the compositions of heavy and light grains are very different, with light grains being magnesium-rich (silicon-deficient), whereas the mean Mg+/Si+ ratio in heavy grains is similar to CI chondritic.  The marked difference in composition between light and heavy grains indicates that the origin of the two grain populations might be different.
C1 UNIV MARYLAND,COLLEGE PK,MD 20742.
C3 University System of Maryland; University of Maryland College Park
RP MUKHIN, L (corresponding author), MOSCOW SPACE RES INST,PROFSOYUZNAYA STR 84-32,MOSCOW 117810,USSR.
NR 21
TC 15
Z9 15
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 480
EP 481
DI 10.1038/350480a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300042
DA 2026-03-10
ER

PT J
AU GERMAIN, RN
   HENDRIX, LR
AF GERMAIN, RN
   HENDRIX, LR
TI MHC CLASS-II STRUCTURE, OCCUPANCY AND SURFACE EXPRESSION DETERMINED BY POST-ENDOPLASMIC RETICULUM ANTIGEN-BINDING
SO NATURE
LA English
DT Article
ID major histocompatibility complex; b-cell alloantigens; hla-dr antigens; invariant chain; monoclonal-antibody; t-cells; immunogenic peptides; ia antigens; molecules; recognition
AB Class II major histocompatibility complex molecules undergo a change in structure upon stable binding of peptide antigen. Analysis of the site and extent of this change among class II molecules of splenic antigen-presenting cells reveals the preference of class II for peptide acquisition outside the endoplasmic reticulum and indicates that the class II presentation system is not saturated with self peptides. There are numerous empty class II molecules on the cell surface and peptide antigen is evidently important in regulating surface class II expression.
RP GERMAIN, RN (corresponding author), NIAID,IMMUNOL LAB,LYMPHOCYTE BIOL SECT,BETHESDA,MD 20892, USA.
NR 63
TC 406
Z9 427
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 134
EP 139
DI 10.1038/353134a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100043
PM 1891045
DA 2026-03-10
ER

PT J
AU GOPALKRISHNA
   SUBRAMANIAN, K
AF GOPALKRISHNA
   SUBRAMANIAN, K
TI GRAVITATIONAL MICROLENSING OF THE RELATIVISTIC JETS OF QUASARS
SO NATURE
LA English
DT Article
ID extragalactic radio-sources; bl lacertae objects; rapid variability; polarization; qso-0957+561a,b; stars; qsos; ghz
AB GRAVITATIONAL microlensing of quasars has been invoked to account for their observed optical variability 1-3 - the timescale being as short as a few years for microlenses the size of Jupiter moving at approximately 300 km s-1 (ref. 4).  But some blazars (conspicuously active quasars) show ultra-rapid variability on timescales as short as 1 hour in the optical 5-7 and 1 day at centimetre wavelengths 8-11.  Blazars are known to contain relativistic jets directed within approximately 10-degrees of the line of sight 12, and bright knots in these jets could appear to move superluminally with respect not only to the blazar nucleus but also to any galaxy near the line of sight.  We argue here that any such superlumimal motion 13, if microlensed by a star in an intervening galaxy, can produce the requisite ultra-rapid variations, even in the absence of intrinsic flux variations in the jet.  Moreover, the same mechanism can naturally account for the commonly observed approximately 1-day variability of compact radio sources at centimetre wavelengths 14.
RP GOPALKRISHNA (corresponding author), TATA INST FUNDAMENTAL RES,PO BAG 3,POONA UNIV CAMPUS,POONA 411007,INDIA.
NR 35
TC 33
Z9 34
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 766
EP 768
DI 10.1038/349766a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600046
DA 2026-03-10
ER

PT J
AU WATSON, AJ
   ROBINSON, C
   ROBINSON, JE
   WILLIAMS, PJL
   FASHAM, MJR
AF WATSON, AJ
   ROBINSON, C
   ROBINSON, JE
   WILLIAMS, PJL
   FASHAM, MJR
TI SPATIAL VARIABILITY IN THE SINK FOR ATMOSPHERIC CARBON-DIOXIDE IN THE NORTH-ATLANTIC
SO NATURE
LA English
DT Article
ID ocean; coefficient
AB DIRECT calculation of the air-sea flux of CO2 requires detailed knowledge of the partial pressure of carbon dioxide (P(CO2)) and gas-transfer velocities at the surface of the global ocean 1, with the available observations of surface P(CO2) suggesting that it varies in a smooth manner with season and position over the major ocean regions 2-5.  In spring 1989 we mapped surface P(CO2), total inorganic carbon (TIC), chlorophyll, temperature and salinity at several locations between 47-degrees-N and 60-degrees-N in the northeast Atlantic near 20-degrees-W, observing large variations in P(CO2) on spatial scales of < 100 km, correlated with plankton chlorophyll, surface temperature and TIC.  The variation of P(CO2) with latitude was in the opposite sense to that previously reported for this region 3-5.  Thus, in this ocean area and season at least, the air-sea flux is strongly modulated by biological activity and variable on short spatial scales.  The inhomogeneity observed suggests that estimates of the oceanic sink for fossil fuel inferred from existing data (relatively sparse even in the North Atlantic) will be subject to significant error.
C1 UNIV COLL N WALES,SCH OCEAN SCI,MENAI BRIDGE LL59 5EY,GWYNEDD,WALES.
   INST OCEAN SCI,DEACON LAB,GODALMING GU8 5UB,SURREY,ENGLAND.
C3 Bangor University; NERC National Oceanography Centre
RP WATSON, AJ (corresponding author), PLYMOUTH MARINE LAB,PROSPECT PL,W HOE,PLYMOUTH PL1 3DH,ENGLAND.
NR 16
TC 173
Z9 178
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 50
EP 53
DI 10.1038/350050a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300060
DA 2026-03-10
ER

PT J
AU CULLIS, AG
   CANHAM, LT
AF CULLIS, AG
   CANHAM, LT
TI VISIBLE-LIGHT EMISSION DUE TO QUANTUM SIZE EFFECTS IN HIGHLY POROUS CRYSTALLINE SILICON
SO NATURE
LA English
DT Article
AB LIGHT-emitting devices based on silicon would find many applications in both VLSI and display technologies, but silicon normally emits only extremely weak infrared photoluminescence because of its relatively small and indirect band gap 1.  The recent demonstration of very efficient and multicolour (red, orange, yellow and green) visible light emission from highly porous, electrochemically etched silicon 2,3 has therefore generated much interest.  On the basis of strong but indirect evidence, this phenomenon was initially attributed to quantum size effects within crystalline material 2, but this interpretation has subsequently been extensively debated.  Here we report results from a transmission electron microscopy study which reveals the structure of the porous layers that emit red light under photoexcitation.  Our results constitute direct evidence that highly porous silicon contains quantum-size crystalline structures responsible for the visible emission.  We show that arrays of linear quantum wires are present and obtain images of individual quantum wires of width < 3 nm.
RP CULLIS, AG (corresponding author), ROYAL SIGNALS & RADAR ESTAB,DIV ELECTR,DRA,ST ANDREWS RD,MALVERN WR14 3PS,WORCS,ENGLAND.
NR 15
TC 1260
Z9 1364
U1 3
U2 228
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 335
EP 338
DI 10.1038/353335a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400053
DA 2026-03-10
ER

PT J
AU ZEISKE, T
   SONNTAG, R
   HOHLWEIN, D
   ANDERSEN, NH
   WOLF, T
AF ZEISKE, T
   SONNTAG, R
   HOHLWEIN, D
   ANDERSEN, NH
   WOLF, T
TI LOCAL OXYGEN ORDERING IN SUPERCONDUCTING YBA2CU3O6.4 OBSERVED BY NEUTRON-DIFFRACTION
SO NATURE
LA English
DT Article
ID deficient yba2cu3o7-delta; structural-property; ba2ycu3o7-delta; anomaly
AB THE superconducting transition temperature, T(c), in the YBa2Cu3O6+x system is known to depend not only on the oxygen stoichiometry 1, but also on the degree of oxygen order 2,3.  Observations of oxygen ordering structures by electron microscopy 4,5 have led to the suggestion that the '60-K plateau' near x = 0.5 in the curve of T(c) versus x arises from an ordered structure (the 'ortho-II phase') in which Cu-O and Cu chains alternate in the basal plane 6.  Until now, however, the ortho-II phase has been seen only by electron diffraction, except for one observation at an oxygen stoichiometry of x = 6.7 by X-ray diffraction 7.  Compared with true bulk methods such as X-ray and neutron diffraction, electron diffraction suffers from the disadvantage that only a very small portion of the sample is probed.  Here we report the observation, by neutron diffraction, of local ortho-II ordering in an YBa2Cu3O6.4 crystal (T(c) = 38 K).  The observed correlation lengths along the principal axes are 24b (along the chains), 10a and 2c.  Our observation of the existence of the ortho-II phase for an oxygen stoichiometry close to the minimum for which superconductivity is observed (x almost-equal-to 0.4) supports existing theoretical models 8,9, in particular one 8 that relates T(c) to the presence of two types of ordered domain.
C1 RISO NATL LAB,DEPT PHYS,DK-4000 ROSKILDE,DENMARK.
   KERNFORSCHUNGSZENTRUM KARLSRUHE GMBH,ITP,W-7500 KARLSRUHE 1,GERMANY.
   UNIV TUBINGEN,INST KRISTALLOG,W-7400 TUBINGEN 1,GERMANY.
C3 Technical University of Denmark; Helmholtz Association; Karlsruhe Institute of Technology; Eberhard Karls University of Tubingen
RP ZEISKE, T (corresponding author), HAHN MEITNER INST KERNFORSCH BERLIN GMBH,GLIENICKER STR 100,W-1000 BERLIN 39,GERMANY.
NR 19
TC 80
Z9 81
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 542
EP 544
DI 10.1038/353542a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300060
DA 2026-03-10
ER

PT J
AU SAUNDERS, W
   FRENK, C
   ROWANROBINSON, M
   EFSTATHIOU, G
   LAWRENCE, A
   KAISER, N
   ELLIS, R
   CRAWFORD, J
   XIA, XY
   PARRY, I
AF SAUNDERS, W
   FRENK, C
   ROWANROBINSON, M
   EFSTATHIOU, G
   LAWRENCE, A
   KAISER, N
   ELLIS, R
   CRAWFORD, J
   XIA, XY
   PARRY, I
TI THE DENSITY FIELD OF THE LOCAL UNIVERSE
SO NATURE
LA English
DT Article
ID scale; clusters; galaxy; dipoles; space
AB An all-sky redshift survey of galaxies detected by IRAS (the Infrared Astronomical Satellite) has been used to map the Universe out to 140h-1 Mpc (the Hubble constant H(o) = 100h km s-1 Mpc-1). Well-known superclusters and voids are seen, as are others not previously identified. The inferred underlying distribution of density is found to be skewed to high densities (the voids are larger than the superclusters but depart less from the mean density); and there is more structure on large scales than is predicted by the standard cold dark matter theory of galaxy formation.
C1 QUEEN MARY & WESTFIELD COLL, ASTRON UNIT, LONDON E1 4NS, ENGLAND.
   UNIV DURHAM, DEPT PHYS, DURHAM DH1 3LE, ENGLAND.
   QUEEN MARY & WESTFIELD COLL, DEPT PHYS, LONDON E1 4NS, ENGLAND.
   UNIV TORONTO, CANADIAN INST THEORET ASTROPHYS, TORONTO M5S 1A1, ONTARIO, CANADA.
C3 University of London; Queen Mary University London; Durham University; University of London; Queen Mary University London; University of Toronto
RP SAUNDERS, W (corresponding author), UNIV OXFORD, DEPT ASTROPHYS, KEBLE RD, OXFORD OX2 3RJ, ENGLAND.
NR 31
TC 326
Z9 330
U1 0
U2 0
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 32
EP 38
DI 10.1038/349032a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100041
DA 2026-03-10
ER

PT J
AU INTRILIGATOR, DS
   DRYER, M
AF INTRILIGATOR, DS
   DRYER, M
TI A KICK FROM THE SOLAR-WIND AS THE CAUSE OF COMET HALLEYS FEBRUARY 1991 FLARE
SO NATURE
LA English
DT Article
ID pioneer-10; shocks
AB KNOWLEDGE of the interaction of comets with the solar wind 1,2 was greatly advanced during the 1986 passage of comet Halley, which was studied in situ and by remote sensing more thoroughly than any previous comet flyby 3,4.  Of particular interest and novelty was the large flare 5 that Halley was seen to produce on 12 February 1991, when it was 14.3 AU from the Sun and 18-degrees below the ecliptic plane.  There have been further outbursts, most recently on 17 March 6.  We note that the Sun has been unusually active in recent months, and suggest that a shock wave, generated by the solar flare and propagating through the interplanetary medium, could have caused the comet to flare.  For example, we show that a solar flare on 31 January could plausibly have produced a shock wave that would have reached Halley on 12 February, and would have been sufficiently strong to crack the comet's crust of fluffy ice.
C1 NOAA,SPACE ENVIRONM LAB,BOULDER,CO 80303.
C3 National Oceanic Atmospheric Admin (NOAA) - USA
RP INTRILIGATOR, DS (corresponding author), CARMEL RES CTR,POB 1732,SANTA MONICA,CA 90406, USA.
NR 16
TC 31
Z9 36
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 407
EP 409
DI 10.1038/353407a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600048
DA 2026-03-10
ER

PT J
AU ZOMERDIJK, JCBM
   KIEFT, R
   BORST, P
AF ZOMERDIJK, JCBM
   KIEFT, R
   BORST, P
TI EFFICIENT PRODUCTION OF FUNCTIONAL MESSENGER-RNA MEDIATED BY RNA POLYMERASE-I IN TRYPANOSOMA-BRUCEI
SO NATURE
LA English
DT Article
ID transcription unit; gene; expression; promoter; trans; identification; provides; tubulin; cells; rdna
AB THE unicellular eukaryote Trypanosoma brucei evades the immune defence of its mammalian host by antigenic variation 1. The genes for variant-specific surface glycoproteins (VSGs) are expressed within large multicistronic transcription units 2.  Mature messenger RNAs are produced by trans-splicing and polyadenylation 3-5. A remarkable feature of the transcription of VSG genes is its insensitivity to the RNA polymerase II inhibitor alpha-amanitin 6. This has led to the speculation that RNA polymerase I, normally only involved in the transcription of ribosomal RNA genes, also mediates expression of these surface antigen genes. In higher eukaryotes, however, transcripts produced by RNA polymerase I were found to be poor substrates for processing into mature mRNAs 7-9. In contrast, we show here that the RNA polymerase I of T. brucei can mediate the efficient production of functional mRNA for neomycin phosphotransferase. The exceptional ability may be related to the unusual way in which pre-mRNAs are capped in trypanosomes. In most eukaryotes, mRNAs are modified at their 5' end by a capping activity associated with RNA polymerase II10; in trypanosomes, mRNAs acquire their 5'-cap from capped mini-exon donor RNA by trans-splicing 3-5, a process that could be independent of the RNA polymerase producing the pre-mRNA.
RP ZOMERDIJK, JCBM (corresponding author), NETHERLANDS CANC INST,DIV MOLEC BIOL,PLESMANLAAN 121,1066 CX AMSTERDAM,NETHERLANDS.
NR 24
TC 83
Z9 87
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 772
EP 775
DI 10.1038/353772a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600074
PM 1658658
DA 2026-03-10
ER

PT J
AU LI, XY
   JEANLOZ, R
AF LI, XY
   JEANLOZ, R
TI PHASES AND ELECTRICAL-CONDUCTIVITY OF A HYDROUS SILICATE ASSEMBLAGE AT LOWER-MANTLE CONDITIONS
SO NATURE
LA English
DT Article
ID high-pressures; (mg,fe)sio3 perovskite; temperatures; transformations; h2o
AB THE presence of a small amount of water in the lower mantle might affect in a significant way the geophysical and geochemical properties of its host mineral assemblage 1-5.  Here we present experimental observations of the phase behaviour and the electrical conductivity of a hydrous silicate assemblage synthesized from a mixture of (Mg0.88Fe0.12)SiO3 pyroxene and water under the pressure and temperature conditions of the lower mantle.  Previous studies have shown that anhydrous (Mg, Fe)SiO3 pyroxene transforms to a perovskite structure under these conditions 6-9.  We find that, although the hydrous assemblage is also dominated by the (Mg, Fe)SiO3 perovskite phase, it coexists with the so-called hydrous phase D, of estimated composition (Mg, Fe)SiH2O4.  Our measurements show that the inclusion of small amounts of water in the silicates can enhance the electrical conductivity of the lower-mantle assemblage by more than three orders of magnitude at these temperatures and pressures.
C1 UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720.
C3 University of California System; University of California Berkeley
NR 19
TC 34
Z9 39
U1 1
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 332
EP 334
DI 10.1038/350332a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800089
DA 2026-03-10
ER

PT J
AU KAJIWARA, K
   HAHN, LB
   MUKAI, S
   TRAVIS, GH
   BERSON, EL
   DRYJA, TP
AF KAJIWARA, K
   HAHN, LB
   MUKAI, S
   TRAVIS, GH
   BERSON, EL
   DRYJA, TP
TI MUTATIONS IN THE HUMAN RETINAL DEGENERATION SLOW GENE IN AUTOSOMAL DOMINANT RETINITIS-PIGMENTOSA
SO NATURE
LA English
DT Article
ID rhodopsin gene; rds; mice
AB THE murine retinal degeneration slow (rds) gene is a semidominant mutation with a phenotype having rod and cone photoreceptors that develop abnormally and then slowly degenerate 1-3. The phenotype is a possible model for retinitis pigmentosa, one of the scores of hereditary human retinal degenerations, which is also characterized by photoreceptor degeneration. We report here three mutations of the human homologue of the rds gene (RDS) that cosegregate with autosomal dominant retinitis pigmentosa in separate families. Our results indicate that some cases of autosomal dominant retinitis pigmentosa are due to mutations at the RDS locus.
C1 HARVARD UNIV,MASSACHUSETTS EYE & EAR INFIRM,SCH MED,HOWE LAB OPHTHALMOL,243 CHARLES ST,BOSTON,MA 02114.
   HARVARD UNIV,MASSACHUSETTS EYE & EAR INFIRM,SCH MED,BERMAN GUND LAB STUDY RETINAL DEGENERAT,BOSTON,MA 02114.
   UNIV TEXAS,SW MED CTR,DEPT PSYCHIAT,DALLAS,TX 75237.
C3 Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Massachusetts Eye & Ear Infirmary; Harvard University; Harvard University Medical Affiliates; Massachusetts Eye & Ear Infirmary; Harvard Medical School; University of Texas System; University of Texas Southwestern Medical Center; University of Texas Dallas
RP DRYJA, TP (corresponding author), HARVARD UNIV,MASSACHUSETTS EYE & EAR INFIRM,SCH MED,HOWE LAB OPHTHALMOL,243 CHARLES ST,BOSTON,MA 02114, USA.
NR 19
TC 390
Z9 417
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 480
EP 483
DI 10.1038/354480a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800061
PM 1684223
DA 2026-03-10
ER

PT J
AU WARING, DA
   KENYON, C
AF WARING, DA
   KENYON, C
TI REGULATION OF CELLULAR RESPONSIVENESS TO INDUCTIVE SIGNALS IN THE DEVELOPING C-ELEGANS NERVOUS-SYSTEM
SO NATURE
LA English
DT Article
ID nematode caenorhabditis-elegans; gene; lineages; homeobox
AB IN Caenorhabditis elegans, cell-cell communication is required to form a simple pattern of sensory ray neurons and cuticular structures (alae).  The C. elegans pal-1 gene initiates one developmental pathway (ray lineages) simply by blocking a cell-cell interaction that induces an alternative pathway 1.  Here we show by mosaic analysis that pal-1+ acts by preventing specific cells from responding to inductive signals.  The results indicate that although cell signals play a critical role in generating this pattern, they do not provide spatial information.  Instead, signals are sent to many, if not all, of the precursor cells, and the ability to respond is spatially restricted.  This patterning strategy thus differs from many well known models for pattern formation in which localized inductive signals influence a subset of cells within a field.  We find that pal-1 encodes a homeodomain protein and so is likely to regulate transcription.  The pal-1+ protein could block the response to cell signals either by repressing genes involved in signal transduction or by acting directly on downstream genes in a way that neutralizes the effects of the intercellular signals.  Genetic experiments indicate that one candidate for such a downstream gene is the Antennapedia-like homeotic selector gene mab-5.
RP WARING, DA (corresponding author), UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143, USA.
NR 14
TC 51
Z9 64
U1 0
U2 0
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 712
EP 715
DI 10.1038/350712a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000062
PM 2023634
DA 2026-03-10
ER

PT J
AU MATSUI, Y
   TOKSOZ, D
   NISHIKAWA, S
   NISHIKAWA, SI
   WILLIAMS, D
   ZSEBO, K
   HOGAN, BLM
AF MATSUI, Y
   TOKSOZ, D
   NISHIKAWA, S
   NISHIKAWA, SI
   WILLIAMS, D
   ZSEBO, K
   HOGAN, BLM
TI EFFECT OF STEEL FACTOR AND LEUKEMIA INHIBITORY FACTOR ON MURINE PRIMORDIAL GERM-CELLS IN CULTURE
SO NATURE
LA English
DT Article
ID tyrosine kinase receptor; c-kit; growth-factor; w-locus; si-locus; proto-oncogene; mouse; ligand; expression; identification
AB DESPITE the importance of germ cells to the survival of species, surprisingly little is known about their embryological origin, proliferation, migration and entry into mitotic arrest or meiosis 1-5. Mutations in the murine Dominant White Spotting (W) and Steel genes, which respectively encode the c-kit tyrosine kinase receptor and the c-kit ligand (or Steel factor), impair the development of primordial germ cells (PGCs) in vivo, as well as haematopoietic stem cells and neural crest-derived melanoblast 3,6-16. Here we use a monoclonal antibody against c-kit tyrosine kinase receptor and recombinant Steel factor to study the c-kit receptor-ligand system in cultured PGCs. In addition, we show that leukaemia inhibitory factor (also known as differentiation inhibitory activity) 17,18, a factor secreted by STO fibroblasts, can stimulate proliferation of primordial germ cells in vitro.
C1 VANDERBILT UNIV,MED CTR,SCH MED,DEPT CELL BIOL,NASHVILLE,TN 37232.
   HARVARD UNIV,SCH MED,DANA FARBER CANC INST,BOSTON,MA 02115.
   CHILDRENS HOSP MED CTR,HOWARD HUGHES MED INST,BOSTON,MA 02115.
   KUMAMOTO UNIV,INST MED IMMUNOL,DEPT PATHOL,KUMAMOTO 860,JAPAN.
   AMGEN INC,AMGEN CTR,THOUSAND OAKS,CA 91320.
C3 Vanderbilt University; Harvard University; Harvard University Medical Affiliates; Dana-Farber Cancer Institute; Harvard Medical School; Howard Hughes Medical Institute; Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Kumamoto University; Amgen
NR 28
TC 401
Z9 451
U1 1
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 750
EP 752
DI 10.1038/353750a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600067
PM 1719421
DA 2026-03-10
ER

PT J
AU BINETRUY, B
   SMEAL, T
   KARIN, M
AF BINETRUY, B
   SMEAL, T
   KARIN, M
TI HA-RAS AUGMENTS C-JUN ACTIVITY AND STIMULATES PHOSPHORYLATION OF ITS ACTIVATION DOMAIN
SO NATURE
LA English
DT Article
ID transcription factor ap-1; proto-oncogene; mouse fibroblasts; gene-expression; transformation; interacts; encodes; element; product; cells
AB Ha-Ras augments c-Jun-mediated transactivation by potentiating the activity of the c-Jun activation domain. Ha-Ras also causes a corresponding increase in phosphorylation of specific sites in that part of the c-Jun protein. A Ha-Ras-induced protein kinase cascade resulting in hyperphosphorylation of the c-Jun activation domain could explain how these oncoproteins cooperate to transform rat embryo fibroblasts.
C1 UNIV CALIF SAN DIEGO, SCH MED, CTR MOLEC GENET, DEPT PHARMACOL, 0636, LA JOLLA, CA 92093 USA.
   UNIV CALIF SAN DIEGO, SCH MED, CTR MOLEC GENET, DEPT BIOL, LA JOLLA, CA 92093 USA.
C3 University of California System; University of California San Diego; University of California System; University of California San Diego
NR 50
TC 624
Z9 657
U1 0
U2 9
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 122
EP 127
DI 10.1038/351122a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500041
PM 1903181
DA 2026-03-10
ER

PT J
AU HOUGHTEN, RA
   PINILLA, C
   BLONDELLE, SE
   APPEL, JR
   DOOLEY, CT
   CUERVO, JH
AF HOUGHTEN, RA
   PINILLA, C
   BLONDELLE, SE
   APPEL, JR
   DOOLEY, CT
   CUERVO, JH
TI GENERATION AND USE OF SYNTHETIC PEPTIDE COMBINATORIAL LIBRARIES FOR BASIC RESEARCH AND DRUG DISCOVERY
SO NATURE
LA English
DT Article
ID solid-phase synthesis; antigenic determinant; ligands; protein; acid
AB EXISTING methods for the synthesis and screening of large numbers of peptides are limited by their inability to generate and screen the requisite number (millions) of individual peptides 1-4 and/or their inability to generate unmodified free peptides in quantities able to interact in solution 4-8. We have circumvented these limitations by developing synthetic peptide combinatorial libraries composed of mixtures of free peptides in quantities which can be used directly in virtually all existing assay systems. The screening of these heterogeneous libraries, along with an iterative selection and synthesis process, permits the systematic identification of optimal peptide ligands. Starting with a library composed of more than 34 million hexa-peptides, we present here the precise identification of an antigenic determinant recognized by a monoclonal antibody as well as the straightforward development of new potent antimicrobial peptides.
RP HOUGHTEN, RA (corresponding author), TORREY PINES INST MOLEC STUDIES,3550 GEN ATOM COURT,SAN DIEGO,CA 92121, USA.
NR 25
TC 1154
Z9 1620
U1 2
U2 123
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 84
EP 86
DI 10.1038/354084a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900065
PM 1719428
DA 2026-03-10
ER

PT J
AU TREACY, MN
   HE, X
   ROSENFELD, MG
AF TREACY, MN
   HE, X
   ROSENFELD, MG
TI I-POU - A POU-DOMAIN PROTEIN THAT INHIBITS NEURON-SPECIFIC GENE ACTIVATION
SO NATURE
LA English
DT Article
ID achaete-scute complex; dna-binding proteins; drosophila-melanogaster; transcription factor; molecular-genetics; glucocorticoid receptor; caenorhabditis-elegans; dopa decarboxylase; early neurogenesis; segmentation gene
AB A novel, structurally distinct POU-domain protein has been identified that inhibits activation by another positive POU-domain regulator of neuron-specific transcription units. Two Drosophila POU-domain proteins, I-POU and Cf1-a, are coexpressed in overlapping subsets of neurons during development. Because I-POU lacks two basic residues in the N terminus of its homeodomain, it cannot bind DNA, but it does form a stable heterodimeric complex with Cf1-a, preventing Cf1-a from binding to DNA recognition elements and from transactivating the dopa-decarboxylase gene. The inhibition by I-POU provides a potential strategy by which the activation of genes in development is controlled by a homeodomain-containing protein that does not bind DNA.
C1 UNIV CALIF SAN DIEGO, SCH MED, DEPT BIOL, LA JOLLA, CA 92093 USA.
   UNIV CALIF SAN DIEGO, SCH MED, HOWARD HUGHES MED INST, LA JOLLA, CA 92093 USA.
C3 University of California System; University of California San Diego; Howard Hughes Medical Institute; University of California System; University of California San Diego
RP TREACY, MN (corresponding author), UNIV CALIF SAN DIEGO, SCH MED, EUKARYOT REGULATORY BIOL PROGRAM, 9500 GILMAN DR, LA JOLLA, CA 92093 USA.
NR 64
TC 202
Z9 210
U1 0
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 577
EP 584
DI 10.1038/350577a0
PG 8
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200049
PM 1673230
DA 2026-03-10
ER

PT J
AU PRIEDE, IG
   BAGLEY, PM
   ARMSTRONG, JD
   SMITH, KL
   MERRETT, NR
AF PRIEDE, IG
   BAGLEY, PM
   ARMSTRONG, JD
   SMITH, KL
   MERRETT, NR
TI DIRECT MEASUREMENT OF ACTIVE DISPERSAL OF FOOD-FALLS BY DEEP-SEA DEMERSAL FISHES
SO NATURE
LA English
DT Article
ID atlantic-ocean; abyssal; coryphaenoides; insitu; bait
AB BAITED cameras on the deep ocean floor first revealed the presence of communities of scavengers, including deep demersal fishes capable of consuming food falls and thus dispersing surface-derived organic carbon 1-3. By embedding acoustic transmitters in baits and deploying them together with an automatic tracking system and cameras on the sea floor 4, 5, we have now tracked the speeds and directions of departing deep demersal scavenging fishes. At a series of stations between 4,000 and 6,000 m deep in the Northern Hemisphere, in contrasting trophic regimes, we have found that two closely related species of fish, Coryphaenoides (Nematonurus) armatus and C.(N.) yaquinae have a significant role in bait dispersal. Even in remote oligotrophic locations, transmitters were consumed rapidly and were removed from the area of detection at a mean velocity of 0.11 m s-1. We find that these fish are active foragers, constantly moving independently of bottom currents. This result is contrary to previous speculation of passive or drifting strategies 6 which might have been expected to conserve energy in a food-limiting environment.
C1 UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, DIV MARINE BIOL RES, LA JOLLA, CA 92093 USA.
   NAT HIST MUSEUM, DEPT ZOOL, LONDON SW7 5BD, ENGLAND.
C3 University of California System; University of California San Diego; Scripps Institution of Oceanography; Natural History Museum London
RP PRIEDE, IG (corresponding author), UNIV ABERDEEN, DEPT ZOOL, TILLYDRONE AVE, ABERDEEN AB9 2TN, SCOTLAND.
NR 17
TC 96
Z9 107
U1 0
U2 11
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 647
EP 649
DI 10.1038/351647a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200064
DA 2026-03-10
ER

PT J
AU BARON, R
   JOSEPH, RD
   OWEN, T
   TENNYSON, J
   MILLER, S
   BALLESTER, GE
AF BARON, R
   JOSEPH, RD
   OWEN, T
   TENNYSON, J
   MILLER, S
   BALLESTER, GE
TI IMAGING JUPITER AURORAE FROM H-3+ EMISSIONS IN THE 3-4 MU-M BAND
SO NATURE
LA English
DT Article
ID south polar aurorae; fundamental-band; iue data; north; spectrometry; voyager
AB SINCE H-3+ was first spectroscopically detected on Jupiter 1,2, there has been considerable interest in using this simple molecular ion to probe conditions existing in the planet's auroral regions.  Here we present a series of images of Jupiter recorded at wavelengths sensitive to emission by H-3+, which reveal the spatial distribution of excited H-3+ molecular ions in the jovian ionosphere, as seen from Earth.  We believe that they provide high-spatial-resolution images of polar aurorae on Jupiter.  They suggest that the intensity of the auroral emission can vary on a timescale of an hour, a shorter period than had previously been noted.  We also find that the spatial distribution of H-3+ emissions correlates only partially with the loci of auroral activity inferred from ultraviolet and longer-wavelength infrared observations.  The H-3+ emission may therefore be controlled by auroral processes that are different from those responsible for the ultraviolet and infrared emissions.
C1 UNIV LONDON UNIV COLL,DEPT PHYS & ASTRON,LONDON WC1E 6BT,ENGLAND.
   UNIV OXFORD,DEPT EARTH SCI,OXFORD OX1 3PR,ENGLAND.
C3 University of London; University College London; University of Oxford
RP BARON, R (corresponding author), UNIV HAWAII,INST ASTRON,2680 WOODLAWN DR,HONOLULU,HI 96822, USA.
NR 22
TC 94
Z9 95
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 539
EP 542
DI 10.1038/353539a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300059
PM 11538254
DA 2026-03-10
ER

PT J
AU CALLAGHAN, PT
   COY, A
   MACGOWAN, D
   PACKER, KJ
   ZELAYA, FO
AF CALLAGHAN, PT
   COY, A
   MACGOWAN, D
   PACKER, KJ
   ZELAYA, FO
TI DIFFRACTION-LIKE EFFECTS IN NMR DIFFUSION STUDIES OF FLUIDS IN POROUS SOLIDS
SO NATURE
LA English
DT Article
AB THE transport of fluids in porous media is of importance in a wide range of areas, such as oil recovery, heterogeneous catalysis and biological perfusion. The pulsed gradient spin-echo (PGSE) NMR technique has been used for many years to characterize diffusion and flow in such systems 1-3. The analogy between NMR measurements in a field gradient and diffraction has been pointed out in the context of NMR imaging 4 and, more recently, diffraction-like effects in the PGSE experiment have been discussed for diffusion in both impermeable 5 and connected 6 structures. The gradient pulse area plays the role of a wavevector, q, which can probe the structure in which the fluid diffuses. Here we report experimental confirmation of these predicted effects from proton NMR studies of a water-saturated, orientationally disordered, loosely packed array of monodisperse polystyrene spheres. The PGSE-NMR experiments may thus be used to provide an indirect, averaged image of the internal structure of porous solids at a resolution higher than that achievable with conventional NMR imaging. This is particularly advantageous for measurements on large samples, as the resolution available with the PGSE method depends only on the available range of gradient pulse amplitude and duration and is unconstrained by the factors determining resolution in conventional NMR imaging.
C1 BP RES CTR, SUNBURY TW16 7LN, MIDDX, ENGLAND.
C3 BP
RP CALLAGHAN, PT (corresponding author), MASSEY UNIV, DEPT PHYS, PALMERSTON NORTH, NEW ZEALAND.
NR 9
TC 573
Z9 613
U1 0
U2 99
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 6
PY 1991
VL 351
IS 6326
BP 467
EP 469
DI 10.1038/351467a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FP758
UT WOS:A1991FP75800050
DA 2026-03-10
ER

PT J
AU CHISAKA, O
   CAPECCHI, MR
AF CHISAKA, O
   CAPECCHI, MR
TI REGIONALLY RESTRICTED DEVELOPMENTAL DEFECTS RESULTING FROM TARGETED DISRUPTION OF THE MOUSE HOMEOBOX GENE HOX-1.5
SO NATURE
LA English
DT Article
ID drosophila homeotic genes; neural crest cells; molecular-genetics; dna-sequence; stem-cells; expression; complex; antennapedia; embryo; murine
AB Gene targeting in mouse embryo-derived stem cells has been used to disrupt the homeobox gene hox-1.5.  Mice heterozygous at the hox-1.5 locus appear normal, whereas hox-1.5-/hox-1.5- mice die at or shortly after birth.  These homozygotes are athymic, aparathyroid, have reduced thyroid and submaxillary tissue and exhibit a wide range of throat abnormalities.  In addition, they often feature defects of the heart and arteries as well as craniofacial abnormalities.  These deficiencies are remarkably similar to the pathology of the human congenital disorder DiGeorge's syndrome.
RP CHISAKA, O (corresponding author), UNIV UTAH,SCH MED,HOWARD HUGHES MED INST,DEPT HUMAN GENET,SALT LAKE CITY,UT 84112, USA.
NR 48
TC 757
Z9 806
U1 0
U2 19
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 473
EP 479
DI 10.1038/350473a0
PG 7
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300041
PM 1673020
DA 2026-03-10
ER

PT J
AU WAYNE, RK
   JENKS, SM
AF WAYNE, RK
   JENKS, SM
TI MITOCHONDRIAL-DNA ANALYSIS IMPLYING EXTENSIVE HYBRIDIZATION OF THE ENDANGERED RED WOLF CANIS-RUFUS
SO NATURE
LA English
DT Article
AB THE red wolf, previously endemic to the southeastern United States, declined precipitously in numbers after 1900 because of habitat destruction, predator control programmes, and hybridization with coyotes 1,2.  Hybridization with coyotes probably occurred as these animals, which adjust well to agriculture, became numerous and moved eastwards 1-4.  By 1970, red wolves existed only in extreme southeastern Texas and southwestern Louisiana (Fig. 1)2.  In 1967, red wolves were classified as endangered and a captive breeding programme was begun in 1974 after passage of the Endangered Species Act, about a year before they became extinct in the wild.  Protein electrophoresis and morphometrics have been used to try to discriminate red wolves from hybrids and coyotes 1,4,5.  But because the average substitution rate of mitochondrial DNA in mammals is much greater than that of nuclear genes 6, mtDNA analysis is a more useful way of distinguishing closely related species.  We have now analysed mtDNA restriction-enzyme sites and cytochrome b gene sequence variation in captive red wolves and in 77 canids sampled during the capture period.  We also used the polymerase chain reaction to amplify and then sequenced mtDNA from red wolf skins collected before substantial hybridization of red wolves with coyotes is thought to have occurred. Phylogenetic analysis indicates that red wolves have either a grey wolf or coyote mtDNA genotype, demonstrating hybridization among these species.  Thus, the red wolf is entirely a hybrid form or a distinct taxon that hybridized with coyotes and grey wolves over much of its previous geographical range.  Our findings, however, do not argue against the continued protection of the red wolf.
C1 UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143.
C3 University of California System; University of California San Francisco
RP WAYNE, RK (corresponding author), UNIV CALIF LOS ANGELES,DEPT BIOL,LOS ANGELES,CA 90024, USA.
NR 16
TC 207
Z9 251
U1 0
U2 113
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 565
EP 568
DI 10.1038/351565a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400058
DA 2026-03-10
ER

PT J
AU KENNETT, JP
   STOTT, LD
AF KENNETT, JP
   STOTT, LD
TI ABRUPT DEEP-SEA WARMING, PALAEOCEANOGRAPHIC CHANGES AND BENTHIC EXTINCTIONS AT THE END OF THE PALEOCENE
SO NATURE
LA English
DT Article
ID isotope data; foraminifera; oxygen; ocean; paleoceanography; events; impact; model
AB A remarkable oxygen and carbon isotope excursion occurred in Antarctic waters near the end of the Palaeocene (approximately 57.33 Myr ago), indicating rapid global warming and oceanographic changes that caused one of the largest deep-sea benthic extinctions of the past 90 million years. In contrast, the oceanic plankton were largely unaffected, implying a decoupling of the deep and shallow ecosystems. The data suggest that for a few thousand years, ocean circulation underwent fundamental changes producing a transient state that, although brief, had long-term effects on environmental and biotic evolution.
C1 UNIV CALIF SANTA BARBARA,DEPT GEOL SCI,SANTA BARBARA,CA 93106.
   UNIV SO CALIF,DEPT GEOL SCI,LOS ANGELES,CA 90089.
C3 University of California System; University of California Santa Barbara; University of Southern California
RP KENNETT, JP (corresponding author), UNIV CALIF SANTA BARBARA,INST MARINE SCI,SANTA BARBARA,CA 93106, USA.
NR 56
TC 1096
Z9 1267
U1 5
U2 234
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 225
EP 229
DI 10.1038/353225a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400048
DA 2026-03-10
ER

PT J
AU KUMAR, KN
   TILAKARATNE, N
   JOHNSON, PS
   ALLEN, AE
   MICHAELIS, EK
AF KUMAR, KN
   TILAKARATNE, N
   JOHNSON, PS
   ALLEN, AE
   MICHAELIS, EK
TI CLONING OF CDNA FOR THE GLUTAMATE-BINDING SUBUNIT OF AN NMDA RECEPTOR COMPLEX
SO NATURE
LA English
DT Article
ID functional expression; protein; family; homology; sequence; brain; shows
AB THE amino acids L-glutamic and L-aspartic acids form the most widespread excitatory transmitter network in mammalian brain 1,2. The excitation produced by L-glutamic acid is important in the early development of the nervous system 3,4, Synaptic plasticity and memory formation 5-6, seizures 7,8 and neuronal degeneration 9,10. The receptors activated by L-glutamic acid are a target for therapeutic intervention in neurodegenerative diseases, brain ischaemia and epilepsy. There are two types of receptors for the excitatory amino acids, those that lead to the opening of cation-selective channels and those that activate phospholipase C (ref. 11). The receptors activating ion channels are NMDA (N-methyl-D-aspartate) and kainate/AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate)-sensitive receptors. The complementary DNAs for the kainate/AMPA receptor 12,13 and for the metabotropic receptor 14 have been cloned. We report here on the isolation and characterization of a protein complex of four major proteins that represents an intact complex of the NMDA receptor ion channel and on the cloning of the cDNA for one ot the subunits of this receptor complex, the glutamate-binding protein.
C1 UNIV KANSAS,DEPT PHARMACOL & TOXICOL,2099 CONSTANT AVE,W CAMPUS,LAWRENCE,KS 66047.
   UNIV KANSAS,CTR BIOMED RES,LAWRENCE,KS 66047.
C3 University of Kansas; University of Kansas
NR 32
TC 154
Z9 168
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 70
EP 73
DI 10.1038/354070a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900060
PM 1719427
DA 2026-03-10
ER

PT J
AU VANTOL, HHM
   BUNZOW, JR
   GUAN, HC
   SUNAHARA, RK
   SEEMAN, P
   NIZNIK, HB
   CIVELLI, O
AF VANTOL, HHM
   BUNZOW, JR
   GUAN, HC
   SUNAHARA, RK
   SEEMAN, P
   NIZNIK, HB
   CIVELLI, O
TI CLONING OF THE GENE FOR A HUMAN DOPAMINE D4-RECEPTOR WITH HIGH-AFFINITY FOR THE ANTIPSYCHOTIC CLOZAPINE
SO NATURE
LA English
DT Article
ID beta-adrenergic-receptor; beta-2-adrenergic receptor; expression; cdna; phosphorylation
AB DOPAMINE receptors belong to the family of G protein-coupled receptors.  On the basis of the homology between these receptors, three different dopamine receptors (D1, D2, D3) have been cloned 1-7.  Dopamine receptors are primary targets for drugs used in the treatment of psychomotor disorders such as Parkinson's disease and schizophrenia 8,9.  In the management of socially withdrawn and treatment-resistant schizophrenics, clozapine 10 is one of the most favoured antipsychotics because it does not cause tardive dyskinesia 11.  Clozapine, however, has dissociation constants for binding to D2 and D3 that are 4 to 30 times the therapeutic free concentration of clozapine in plasma water 12, 13.  This observation suggests the existence of other types of dopamine receptors which are more sensitive to clozapine.  Here we report the cloning of a gene that encodes such a receptor (D4).  The D4 receptor gene has high homology to the human dopamine D2 and D3 receptor genes.  The pharmacological characteristics of this receptor resembles that of the D2 and D3 receptors, but its affinity for clozapine is one order of magnitude higher.  Recognition and characterization of this clozapine neuroleptic site may prove useful in the design of new types of drugs.
C1 OREGON HLTH SCI UNIV,VOLLUM INST ADV BIOMED RES,DEPT CELL BIOL & ANAT,PORTLAND,OR 97201.
   UNIV TORONTO,DEPT PSYCHIAT,TORONTO M5S 1A8,ONTARIO,CANADA.
   CLARKE INST PSYCHIAT,MOLEC NEUROBIOL LAB,TORONTO M5T 1R8,ONTARIO,CANADA.
C3 Oregon Health & Science University; University of Toronto; University of Toronto; Centre for Addiction & Mental Health - Canada
RP VANTOL, HHM (corresponding author), UNIV TORONTO,DEPT PHARMACOL,MED SCI BLDG,TORONTO M5S 1A8,ONTARIO,CANADA.
NR 32
TC 1974
Z9 2129
U1 0
U2 107
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 610
EP 614
DI 10.1038/350610a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200060
PM 1840645
DA 2026-03-10
ER

PT J
AU MICHAELIS, MM
   DEMPERS, CA
   KOSCH, M
   PRAUSE, A
   NOTCUTT, M
   CUNNINGHAM, PF
   WALTHAM, JA
AF MICHAELIS, MM
   DEMPERS, CA
   KOSCH, M
   PRAUSE, A
   NOTCUTT, M
   CUNNINGHAM, PF
   WALTHAM, JA
TI A GAS-LENS TELESCOPE
SO NATURE
LA English
DT Article
ID laser
AB A GAS lens is capable of focusing light if the temperature, and therefore refractive index, of a gas is made to vary across an optical aperture in a suitable manner.  Practical applications of gas lenses were pursued thirty years ago 1,2 in the context of power transmission by laser beams, but little work has been done since then.  It was recently shown, however, that a gas lens can focus a laser beam well enough to drill holes in a metal sheet 3, and it has been argued 4 that gas lenses are 'varifocal' devices with negligible dispersion from ultraviolet to infrared wavelengths, and that they may be able to transmit and focus more powerful laser beams than conventional lenses can cope with.  They may therefore find some application in laser-driven thermonuclear experiments 5.  Here we describe another application of gas lenses:  telescopy.  We have constructed a simple gas lens telescope, and have used it to make images of the Sun and the Moon.
RP MICHAELIS, MM (corresponding author), UNIV NATAL,DEPT PHYS,DURBAN,SOUTH AFRICA.
NR 12
TC 25
Z9 26
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 547
EP 548
DI 10.1038/353547a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300062
DA 2026-03-10
ER

PT J
AU KEMPE, S
   KAZMIERCZAK, J
   LANDMANN, G
   KONUK, T
   REIMER, A
   LIPP, A
AF KEMPE, S
   KAZMIERCZAK, J
   LANDMANN, G
   KONUK, T
   REIMER, A
   LIPP, A
TI LARGEST KNOWN MICROBIALITES DISCOVERED IN LAKE VAN, TURKEY
SO NATURE
LA English
DT Article
AB MICROBIALITES are organosedimentary deposits produced by benthic microbial communities interacting with detrital or chemical sediments 1. Calcareous cyanobacterial microbialites defined as stromatolites and thrombolites were common in ancient shallow marine environments 2. Today, they are restricted to a few lacustrine and perimarine settings. This restriction may result from changes in seawater chemistry through time 3-6, particularly from alteration in supersaturation with respect to carbonate minerals 7.  The largest known calcareous microbialites (several metres high) were formed in the late Precambrian 8.  Here we report the discovery of enormous (approximately 40 m high) tower-like microbialites from alkaline (pH > 9.7) Lake Van, eastern Anatolia. Growth is by mats of coccoid cyanobacteria (Pleurocapsa group) permineralizing in situ with aragonite and by inorganically precipitated calcite.  Certain aspects of these microbialites resemble Proterozoic marine stromatolites 9.
C1 POLISH ACAD SCI,INST PALEOBIOL,AL ZWIRKI & WIGURY 93,PL-02089 WARSAW,POLAND.
   UNIV HAMBURG,INST BIOGEOCHEM & MARINE CHEM,W-2000 HAMBURG 13,GERMANY.
   DOKUZ EYLUL UNIV,INST MARINE SCI & TECHNOL,IZMIR,TURKEY.
C3 Polish Academy of Sciences; Institute of Paleobiology of the Polish Academy of Sciences; University of Hamburg; Dokuz Eylul University
NR 22
TC 209
Z9 230
U1 1
U2 31
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 605
EP 608
DI 10.1038/349605a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000058
DA 2026-03-10
ER

PT J
AU TAVANI, M
AF TAVANI, M
TI ORBITAL EVOLUTION OF LOW-MASS X-RAY BINARIES DUE TO RADIATION DRIVEN MASS-TRANSFER
SO NATURE
LA English
DT Article
ID 4u 1820-30; cygnus-x-3; systems; winds
AB A LOW-MASS X-ray binary (LMXB) consists of a compact star, probably a neutron star, accreting mass from a low-mass (less-than-or-similar-to 1 M.) companion via an accretion disk.  Of approximately 100 known LMXBs in the Galaxy, only four have stable enough X-ray modulations to have allowed the reliable determination of orbital period changes.  For these four LMXBs, all of which have P(orb) less-than-or-similar-to 5.6 h, the measured values 1-4 of P(orb)/P(orb) disagree markedly with what would be expected for orbital evolution driven by angular momentum loss due to gravitational radiation, possibly supplemented by magnetic braking; the empirically derived timescale for orbital evolution is approximately 100 times less than expected.  On the assumption that the observed period changes are secular, and not due to some longer-term periodic change, I argue here that the observed behaviour of LMXBs can be explained as the result of mass loss from the companion star caused by irradiation of the secondary star and accretion disk by the primary 5.  The typical lifetime of a radiation-driven LMXB is expected to be approximately 10(6)-10(7) yr.  This reduced evolutionary timescale can resolve the statistical discrepancy between the number of binary millisecond pulsars and of their presumed LMXB progenitors if about half of all the LMXBs are radiation-driven 5-7.
C1 UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720.
C3 University of California System; University of California Berkeley
RP TAVANI, M (corresponding author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550, USA.
NR 29
TC 27
Z9 29
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 39
EP 41
DI 10.1038/351039a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300050
DA 2026-03-10
ER

PT J
AU HOUSTON, H
   WILLIAMS, Q
AF HOUSTON, H
   WILLIAMS, Q
TI FAST RISE TIMES AND THE PHYSICAL-MECHANISM OF DEEP EARTHQUAKES
SO NATURE
LA English
DT Article
ID moment tensor solutions; phase-transformations; focus earthquakes; global seismicity; high-pressure; 201 moderate; olivine; mantle; stress; lithosphere
AB EARTHQUAKES at depths of > 300 km are similar to shallower events in that they are dominantly of double-couple character 1, implying that shearing motion has taken place at depth. But because increased friction at these high pressures inhibits brittle fracture 2,3, various other mechanisms, related to phase transformations, have been invoked to explain the occurrence of deep earthquakes 4-10. As yet, however, no consistent differences have been found between the source characteristics of deep (> 300 km) and intermediate-depth (< 300 km) earthquakes 2,11-13. Here we report a systematic global survey of the rise times and stress drops of deep and intermediate earthquakes. (The rise time is defined as the time from rupture initiation to peak moment release rate.) When the rise times are scaled to the seismic moment release of the events, their average is nearly twice as fast for events deeper than approximately 450 km as for shallower events. This difference may ultimately provide an experimental means of testing proposed mechanisms for the generation of deep seismicity.
RP HOUSTON, H (corresponding author), UNIV CALIF SANTA CRUZ, EARTH SCI BOARD, INST TECTON, SANTA CRUZ, CA 95064 USA.
NR 28
TC 42
Z9 43
U1 0
U2 8
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 520
EP 522
DI 10.1038/352520a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600059
DA 2026-03-10
ER

PT J
AU HEBBELN, D
   WEFER, G
AF HEBBELN, D
   WEFER, G
TI EFFECTS OF ICE COVERAGE AND ICE-RAFTED MATERIAL ON SEDIMENTATION IN THE FRAM STRAIT
SO NATURE
LA English
DT Article
ID particle-flux; sea
AB AS little is known about pelagic sedimentation processes in Arctic environments 1, the interpretation of biological and chemical processes, as well as the reconstruction of ancient conditions, including those in the glacial North Atlantic, is difficult. Here we provide sediment-trap results, which show that the position of the sea-ice boundary significantly influences the particle flux. The seasonal variability of the particle flux differed markedly in the various sediment-trap sites in Fram Strait, depending on the behaviour of the sea ice. Under complete ice cover, sedimentation is very low, whereas maximum sedimentation is found at the ice margin. The highest particle flux observed, showing a large lithogenic component, was observed at the ice edge where the water was warmer (> 2-degrees-C). We find that high biogenic opal fluxes are characteristic of the summer ice margin, indicating that the sedimentary record of opal fluxes may allow the position of ice margins in the past to be reconstructed.
RP HEBBELN, D (corresponding author), UNIV BREMEN, POSTFACH 330440, W-2800 BREMEN 33, GERMANY.
NR 13
TC 148
Z9 157
U1 0
U2 16
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 409
EP 411
DI 10.1038/350409a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200044
DA 2026-03-10
ER

PT J
AU JENKINSON, DS
   ADAMS, DE
   WILD, A
AF JENKINSON, DS
   ADAMS, DE
   WILD, A
TI MODEL ESTIMATES OF CO2 EMISSIONS FROM SOIL IN RESPONSE TO GLOBAL WARMING
SO NATURE
LA English
DT Article
ID terrestrial carbon storage; c-14-labeled ryegrass; plant-material; decomposition; field; straw
AB ONE effect of global warming will be to accelerate the decomposition of soil organic matter, thereby releasing CO2 to the atmosphere, which will further enhance the warming trend 1-7.  Such a feedback mechanism could be quantitatively important, because CO2 is thought to be responsible for approximately 55% of the increase in radiative forcing arising from anthropogenic emissions of gases to the atmosphere 8, and there is about twice as much carbon in the top metre of soil as in the atmosphere 9.  Here we use the Rothamsted model for the turnover of organic matter in soil 3 to calculate the amount of CO2 that would be released from the world stock of soil organic matter if temperatures increase as predicted, the annual return of plant debris to the soil being held constant.  If world temperatures rise by 0.03-degrees-C yr-1 (the increase considered as most likely by the Intergovernmental Panel on Climate Change 8), we estimate that the additional release of CO2 from soil organic matter over the next 60 years will be 61 x 10(15) gC.  This is approximately 19% of the CO2 that will be released by combustion of fossil fuel during the next 60 years if present use of fuel continues unabated.
C1 ROTHAMSTED EXPTL STN,HARPENDEN AL5 2JQ,HERTS,ENGLAND.
C3 UK Research & Innovation (UKRI); Biotechnology and Biological Sciences Research Council (BBSRC); Rothamsted Research
RP JENKINSON, DS (corresponding author), UNIV READING,DEPT SOIL SCI,READING RG1 5AQ,BERKS,ENGLAND.
NR 23
TC 815
Z9 1145
U1 4
U2 406
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 23
PY 1991
VL 351
IS 6324
BP 304
EP 306
DI 10.1038/351304a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FM976
UT WOS:A1991FM97600055
DA 2026-03-10
ER

PT J
AU EBISUZAKI, T
   MAKINO, J
   OKUMURA, SK
AF EBISUZAKI, T
   MAKINO, J
   OKUMURA, SK
TI MERGING OF 2 GALAXIES WITH CENTRAL BLACK-HOLES
SO NATURE
LA English
DT Article
ID elliptical galaxy; density
AB OBSERVATIONS of elliptical galaxies show a positive correlation 1,2 between total luminosity and core radius, defined as the radius at which surface luminosity becomes half of the central value. This has been taken as evidence against the idea that ellipticals are the result of galaxy mergers, because in simulated mergers 3-5 the core radius remained almost constant. In those simulations, the galaxies contained no central black holes, but there is a body of evidence to suggest that such black holes are common in ellipticals 6.  Here, we present simulations of the merging of identical galaxies with and without central black holes, and find that when black holes are included, the merged galaxy acquires an isothermal core comparable in mass to the sum of the two initial black holes. Furthermore, the ratio of the core radius to the half-mass radius is approximately the same as the ratio of the black hole mass to the total galaxy mass, a result also consistent with observational evidence. These results, which can be understood by means of simple analytical arguments, suggest that most elliptical galaxies contain central black holes with masses comparable to the mass of their cores.
C1 UNIV TOKYO,COLL ARTS & SCI,DEPT INFORMAT SCI & GRAPH,TOKYO 153,JAPAN.
C3 University of Tokyo
RP EBISUZAKI, T (corresponding author), UNIV TOKYO,COLL ARTS & SCI,DEPT EARTH SCI & ASTRON,3-8-1 KOMABA,MEGURO KU,TOKYO 153,JAPAN.
NR 22
TC 174
Z9 182
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 212
EP 214
DI 10.1038/354212a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800042
DA 2026-03-10
ER

PT J
AU BLOCK, DL
   WAINSCOAT, RJ
AF BLOCK, DL
   WAINSCOAT, RJ
TI MORPHOLOGICAL DIFFERENCES BETWEEN OPTICAL AND INFRARED IMAGES OF THE SPIRAL GALAXY NGC309
SO NATURE
LA English
DT Article
ID luminosity
AB THE morphological classification of spiral galaxies into various types is suspected to be highly dependent on the wavelength of observation 1, because optical images emphasize young population I stars at the expense of other stellar types, as well as ionized gas and dust. Extension of the classification of galaxies out to wavelengths of a few micrometres has had to await the development of large-format near-infrared array cameras. We present here images at 2.1-mu-m wavelength of NGC309, one of the largest 'grand design' (type ScI) spiral galaxies, obtained with the 256 x 256 array camera developed for the NICMOS (near-infrared camera and multiobject spectrograph) instrument, designed for installation on the Hubble Space Telescope. Optically, NGC309 presents a classic multi-arm morphology, but at 2.1-mu-m we see a two-arm spiral and the appearance of a prominent central bar; it resembles the SBa galaxy NGC1358. These studies underscore existing indications 2 that the disk structure of spiral galaxies may be unrelated to the Hubble type assigned from the transient population I morphology.
C1 UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822.
C3 University of Hawaii System
RP BLOCK, DL (corresponding author), UNIV WITWATERSRAND,DEPT COMP & APPL MATH,PRIVATE BAG 3,WITS 2050,JOHANNESBURG 2001,SOUTH AFRICA.
NR 22
TC 93
Z9 96
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 48
EP 50
DI 10.1038/353048a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500051
DA 2026-03-10
ER

PT J
AU INOUE, I
   NAGASE, H
   KISHI, K
   HIGUTI, T
AF INOUE, I
   NAGASE, H
   KISHI, K
   HIGUTI, T
TI ATP-SENSITIVE K+ CHANNEL IN THE MITOCHONDRIAL INNER MEMBRANE
SO NATURE
LA English
DT Article
ID oxidative-phosphorylation; energy transduction; cationic channel; transport; proteins; import
AB MITOCHONDRIA take up and extrude various inorganic and organic ions, as well as larger substances such as proteins 1-4. The technique of patch clamping should provide real-time information on such transport and on energy transduction in oxidative phosphorylation. It has been applied to detect microscopic currents from mitochondrial membranes and conductances of ion channels in the 5-1,000 pS range in the outer and inner membranes 5-10. These pores are not, however, selective for particular ions. Here we use fused giant mitoplasts prepared from rat liver mitochondria to identify a small conductance channel highly selective for K+ in the inner mitochondrial membrane. This channel can be reversibly inactivated by ATP applied to the matrix side under inside-out patch configuration; it is also inhibited by 4-aminopyridine and by glybenclamide. The slope conductance of the unitary currents measured at negative membrane potentials was 9.7 +/- 1.0 pS (mean +/- s.d., n = 6) when the pipette solution contained 100 mM K+ and the bathing solution 33.3 mM K+. Our results indicate that mitochondria depolarize by generating a K+ conductance when ATP in the matrix is deficient.
C1 UNIV TOKUSHIMA,FAC PHARMACEUT SCI,TOKUSHIMA 770,JAPAN.
C3 Tokushima University
RP INOUE, I (corresponding author), UNIV TOKUSHIMA,INST ENZYME RES,TOKUSHIMA 770,JAPAN.
NR 23
TC 663
Z9 752
U1 0
U2 30
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 244
EP 247
DI 10.1038/352244a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500067
PM 1857420
DA 2026-03-10
ER

PT J
AU POWELL, SK
   CUNNINGHAM, BA
   EDELMAN, GM
   RODRIGUEZBOULAN, E
AF POWELL, SK
   CUNNINGHAM, BA
   EDELMAN, GM
   RODRIGUEZBOULAN, E
TI TARGETING OF TRANSMEMBRANE AND GPI-ANCHORED FORMS OF N-CAM TO OPPOSITE DOMAINS OF A POLARIZED EPITHELIAL-CELL
SO NATURE
LA English
DT Article
ID adhesion molecule uvomorulin; mdck cells; proteins; component; kidney; cdnas; line
AB THE calcium-independent neural cell adhesion molecule N-CAM is expressed transiently during development in many tissues, including epithelia 1. The three naturally occurring principal isoforms 2,3 of N-CAM differ in the way in which they associate with the membrane and in their cytoplasmic domains 4.  These isoforms are generated by developmentally regulated alternative splicing of a single gene 4-6:  the large cytoplasmic domain (ld) form (relative molecular mass 180,000 (M(r) 180K)) is specific for post-mitotic neurons; the 120K small cytoplasmic domain (ssd) and 140K small surface domain (sd) forms also occur on other cell types 7.  One function of the different isoforms could be to specify cellular localization; for example, glycosyl phosphatidyl inositol (GPI)-membrane anchoring acts as a targeting signal for expression on the apical surface of polarized epithelial cells 8,9. Neurons and epithelial cells may use similar mechanisms for polarizing their plasma membrane proteins 10,11.  We have therefore investigated the targeting of GPI-anchored (ssd N-CAM, 120K) and transmembrane forms of N-CAM (sd N-CAM, 140K; Id N-CAM, 180K) by comparing the expression of each after transfection of the appropriate complementary DNAs into polarized epithelial cells. We find that isoforms with alternative modes of membrane association are targeted to different surfaces of polarized epithelial cells:  ssd N-CAM is expressed on the apical surface, whereas sd and ld N-CAM are expressed on the basolateral surface. These results suggest that the different isoforms of N-CAM determine their own diverse cellular destinations. They also support the hypothesis that the GPI anchor acts as an apical targeting signal in epithelia.
C1 ROCKEFELLER UNIV,DEPT DEV & MOLEC BIOL,NEW YORK,NY 10021.
C3 Rockefeller University
RP POWELL, SK (corresponding author), CORNELL UNIV,MED CTR,COLL MED,DEPT CELL BIOL & ANAT,1300 YORK AVE,NEW YORK,NY 10021, USA.
NR 27
TC 106
Z9 108
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 76
EP 77
DI 10.1038/353076a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500062
PM 1831882
DA 2026-03-10
ER

PT J
AU CARAMAZZA, A
   HILLIS, AE
AF CARAMAZZA, A
   HILLIS, AE
TI LEXICAL ORGANIZATION OF NOUNS AND VERBS IN THE BRAIN
SO NATURE
LA English
DT Article
ID category; impairment; language; aphasia
AB THE analysis of neuropsychological disorders of lexical processing has provided important clues about the general organization of the lexical system and the internal structure of the processing components 1-3. Reports of patients with selective dysfunction of specific semantic categories such as abstract versus concrete words 4-6, living things versus inanimate objects 7-11, animals 12-14, fruits and vegetables 15, proper names 16,17 and so forth, support the hypothesis that the neural organization of the semantic processing component is organized in these categories.  There are reports of selective dysfunction of the grammatical categories noun and verb 18-21, suggesting that a dimension of lexical organization is the grammatical class of words.  But the results reported in these studies have not provided unambiguous evidence concerning two fundamental questions about the nature and the locus of this organization within the lexical system.  Is the noun-verb distinction represented in the semantic or in the phonological and orthographic lexicons?  Is grammatical-class knowledge represented independently of lexical forms or is it represented separately and redundantly within each modality-specific lexicon?  Here we report the performance of two brain-damaged subjects with modality-specific deficits restricted principally (H.W.) or virtually only (S.J.D) to verbs in oral and written production, respectively.  The contrasting performance suggests that grammatical-class distinctions are redundantly represented in the phonological and orthographic output lexical components.
C1 HEALTHSOUTH REHABIL CORP,BALTIMORE,MD 21234.
RP CARAMAZZA, A (corresponding author), JOHNS HOPKINS UNIV,DEPT COGNIT SCI,BALTIMORE,MD 21218, USA.
NR 17
TC 528
Z9 583
U1 2
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 788
EP 790
DI 10.1038/349788a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600055
PM 2000148
DA 2026-03-10
ER

PT J
AU FRIEDRICH, B
   HERSCHBACH, DR
AF FRIEDRICH, B
   HERSCHBACH, DR
TI SPATIAL ORIENTATION OF MOLECULES IN STRONG ELECTRIC-FIELDS AND EVIDENCE FOR PENDULAR STATES
SO NATURE
LA English
DT Article
ID optical double-resonance; oriented molecules; spectroscopy; beams; ch3i; ici
AB IN typical collisional or spectroscopic experiments, molecules rotate freely with random spatial orientations.  The resulting isotropic averaging obscures or suppresses much stereodynamical information and has remained a recalcitrant problem.  The only practical means for orienting a molecule itself, rather than just its axis of rotation, has been electric field focusing 1,2.   But this is applicable only to certain rotational states of symmetric top molecules (or equivalent) that exhibit a first-order Stark effect.  Orientation of molecules other than symmetric tops has long been considered to be quite unfeasible 3.  Recently, however, it has been pointed out 4,5 that by exploiting the extreme rotational cooling that can occur in supersonic molecular beams, substantial orientation of diatomic, linear or asymmetric top molecules should become possible at accessible field strengths.  The anisotropy of the Stark effect allows molecules in the lowest few rotational states to be trapped in 'pendular states' and thereby confined to librate (oscillate about the field axis) over a limited angular range.   Here we describe an experiment which demonstrates that oriented pendular states can be obtained for a diatomic molecule with modest field strengths.  With anticipated improvements, this technique should become widely applicable.
RP FRIEDRICH, B (corresponding author), HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138, USA.
NR 20
TC 300
Z9 310
U1 0
U2 77
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 412
EP 414
DI 10.1038/353412a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600050
DA 2026-03-10
ER

PT J
AU DAVIS, RJ
   DEROUANE, EG
AF DAVIS, RJ
   DEROUANE, EG
TI A NONPOROUS SUPPORTED-PLATINUM CATALYST FOR AROMATIZATION OF N-HEXANE
SO NATURE
LA English
DT Article
AB THE cyclization of C6 and C-7 n-alkanes to form aromatic compounds is highly desirable in the petroleum-refining industry.  Platinum metal clusters incorporated into the channels of zeolite L have been found to catalyse the aromatization of hexane and heptane with high activity and selectivity 1,2.  The susceptibility of this catalyst to sulphur poisoning, however, means that the hydrocarbon reagents must be of high purity, free from sulphur contamination 2.  It has been generally believed that the pore structure of the zeolite plays an important part in the selectivity of the catalytic process.  Here we describe a non-porous platinum catalyst that can convert n-hexane to benzene with an activity and selectivity comparable to that of the zeolite.  The catalyst consists of platinum clusters, about 2 nm in diameter, supported on a basic, high-surface-area magnesium oxide stabilized by aluminium.  The product distribution for n-hexane is almost identical to that obtained using the zeolite L catalyst.  These results point to a new approach to hydrocarbon reforming based on metal species supported on highly basic, non-porous carriers.
C1 FAC UNIV NOTRE DAME PAIX,DEPT CHIM LAB CATALYSE,61 RUE BRUXELLE,B-5000 NAMUR,BELGIUM.
   UNIV VIRGINIA,DEPT CHEM ENGN,CHARLOTTESVILLE,VA 22903.
C3 University of Namur; University of Virginia
NR 8
TC 173
Z9 180
U1 1
U2 53
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 313
EP 315
DI 10.1038/349313a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100045
DA 2026-03-10
ER

PT J
AU PAMER, EG
   HARTY, JT
   BEVAN, MJ
AF PAMER, EG
   HARTY, JT
   BEVAN, MJ
TI PRECISE PREDICTION OF A DOMINANT CLASS-I MHC-RESTRICTED EPITOPE OF LISTERIA-MONOCYTOGENES
SO NATURE
LA English
DT Article
ID lymphocytes-t; cells; hemolysin; expression; immunity; growth; determinant; infection; virulence; peptide
AB Listeria monocytogenes is a Gram-positive bacterium which grows in the cytoplasm of eukaryotic cells and can cause severe disease in immunocompromised individuals 1,2. In murine systems CD8+ T lymphocytes have been shown to be important effectors of acquired protective immunity against L. monocytogenes 3-5. Class I MHC restricted CD8+ cytotoxic T lymphocytes (CTL), which lyse J774 macrophage-like targets infected with L. monocytogenes, are induced following in vivo injection of live organisms. Natural peptide epitopes derived from L. monocytogenes can be acid-extracted from heavily infected BALB/c spleens and detected by CTL. A CTL clone, B9, derived from a (BALB/c x C57BL/6)F1 (H-2dxb) mouse, recognizes one of these natural epitopes in an H-2K(d)-restricted fashion. B9 also recognizes P815 (H-2d) mastocytoma cells transfected with the listeriolysin gene. To identify the region of the listeriolysin recognized by CTL we used the H-2K(d) peptide-binding motif described by Rammensee and colleagues 6 to synthesize 11 nonamer peptides. One of these peptides, listeriolysin 91-99, was recognized very efficiently by B9. This represents the first identified class I MHC-restricted epitope of bacteria and demonstrates the utility of the allele-specific motif for predicting CTL epitopes.
C1 UNIV WASHINGTON, DEPT MED, SEATTLE, WA 98195 USA.
C3 University of Washington; University of Washington Seattle
RP PAMER, EG (corresponding author), UNIV WASHINGTON, HOWARD HUGHES MED INST, DEPT IMMUNOL, SEATTLE, WA 98195 USA.
FU Howard Hughes Medical Institute Funding Source: Medline; NIAID NIH HHS [R01 AI019335, R01 AI080619, R01 AI039031, R01 AI046653] Funding Source: Medline
NR 26
TC 402
Z9 448
U1 0
U2 6
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 852
EP 855
DI 10.1038/353852a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200062
PM 1719425
DA 2026-03-10
ER

PT J
AU MAO, HK
   HEMLEY, RJ
AF MAO, HK
   HEMLEY, RJ
TI OPTICAL-TRANSITIONS IN DIAMOND AT ULTRAHIGH PRESSURES
SO NATURE
LA English
DT Article
ID raman-spectroscopy; static pressures; hydrogen; phase; cell; band
AB MANY technological and scientific applications of diamond arise from its unique properties, which include optical transparency in the ultraviolet to infrared, electrical insulation, thermodynamic stability, and unsurpassed strength and hardness 1.  Here we describe optical studies on diamond at ultrahigh pressures (to above 300 GPa) which show that these properties are affected by such stresses. Our spectroscopic measurements show that the optical absorption edge shifts from ultraviolet to red with increasing pressures, and Raman scattering measurements show evidence for new structural transitions, associated with large macroscopic deformation, beginning at a pressure of approximately 150 GPa. The changes are reversible and are associated with intense luminescence peaks at 2.0-2.2 eV under 458-514-nm radiation. Our results may be related to the onset of band-gap closure in the approach to a new high-pressure phase. These spectral features must also be taken into account when diamond is used as optical windows for ultrahigh-pressure investigations 2-5.
C1 CARNEGIE INST WASHINGTON,CTR HIGH PRESSURE RES,WASHINGTON,DC 20015.
C3 Carnegie Institution for Science
RP MAO, HK (corresponding author), CARNEGIE INST WASHINGTON,GEOPHYS LAB,5251 BROAD BRANCH RD NW,WASHINGTON,DC 20015, USA.
NR 26
TC 96
Z9 98
U1 0
U2 36
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 721
EP 724
DI 10.1038/351721a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100055
DA 2026-03-10
ER

PT J
AU MERCIER, N
   VALLADAS, H
   JORON, JL
   REYSS, JL
   LEVEQUE, F
   VANDERMEERSCH, B
AF MERCIER, N
   VALLADAS, H
   JORON, JL
   REYSS, JL
   LEVEQUE, F
   VANDERMEERSCH, B
TI THERMOLUMINESCENCE DATING OF THE LATE NEANDERTHAL REMAINS FROM SAINT-CESAIRE
SO NATURE
LA English
DT Article
ID system; dates
AB ANATOMICALLY modern humans have long been thought to have been responsible for the Aurignacian and Chatelperronian industries of the early Upper Palaeolithic of Western Europe, whereas the Middle Palaeolithic Mousterian industry has been attributed to Neanderthals. The presence of both Middle and Upper Palaeolithic strata at Saint-Cesaire in France offers an excellent opportunity for studying the cultural transition between the two. Saint-Cesaire is the only Chatelperronian site that has yielded really diagnostic hominid fossils, and the discovery there of Neanderthal remains 1 alongside Chatelperronian tools cast doubt on the exclusive association between industries and taxon. We report thermoluminescence dates for 20 burnt flints from the site. Those found near the Neanderthal remains were dated at 36,300 +/- 2,700 years BP (before present), making this specimen the youngest Neanderthal dated so far. This date places the stratum close in age to several French 2,3 but much younger than some Spanish 4,5 Aurignacian sites believed to have been occupied by modern humans. The possibility of contact between the West European Neanderthals and the intrusive modern humans who replaced them cannot therefore be excluded.
C1 CENS,LAB PIERRE SUE,SCI TERRE GRP,F-91191 GIF SUR YVETTE,FRANCE.
   HOTEL ROCHEFORT,DIRECT ANTIQUITES REG POITOU CHARENTES,F-86020 POITIERS,FRANCE.
   UNIV BORDEAUX 1,ANTHROPOL LAB,CNRS,UA 376,F-33405 TALENCE,FRANCE.
C3 Universite Paris Saclay; CEA; Universite de Bordeaux; Centre National de la Recherche Scientifique (CNRS)
RP MERCIER, N (corresponding author), CEA,CNRS LAB,CTR FAIBLES RADIOACT,AVE TERRASSE,F-91198 GIF SUR YVETTE,FRANCE.
NR 31
TC 73
Z9 84
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 737
EP 739
DI 10.1038/351737a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100061
PM 2062366
DA 2026-03-10
ER

PT J
AU BANDARA, LR
   ADAMCZEWSKI, JP
   HUNT, T
   LATHANGUE, NB
AF BANDARA, LR
   ADAMCZEWSKI, JP
   HUNT, T
   LATHANGUE, NB
TI CYCLIN-A AND THE RETINOBLASTOMA GENE-PRODUCT COMPLEX WITH A COMMON TRANSCRIPTION FACTOR
SO NATURE
LA English
DT Article
ID sv40 large-t; e1a proteins; cell-cycle; binding; polypeptides; association; antigen
AB THE retinoblastoma gene (Rb) product is a negative regulator of cellular proliferation 1 an effect that could be mediated in part at the transcriptional level through its ability to complex with the sequence-specific transcription factor DRTF1 (ref. 2). This interaction is modulated by adenovirus E1a, which sequesters the Rb protein 3 and several other cellular proteins 3, including cyclin A (refs 4, 5), a molecule that undergoes cyclical accumulation and destruction during each cell cycle 6,7 and which is required for cell cycle progression 8. Cyclin A, which also complexes with DRTF1, facilitates the efficient assembly of the Rb protein into the complex. This suggests a role for cyclin A in regulating transcription and defines a transcription factor through which molecules that regulate the cell cycle in a negative fashion, such as Rb, and in a positive fashion, such as cyclin A, interact. Mutant loss-of-function Rb alleles, which occur in a variety of tumour cells, also fail to complex with E1a and large T antigen 9,10. Here we report on a naturally occurring loss-of-function Rb allele encoding a protein that fails to complex with DRTF1. This might explain how mutation in the Rb gene prevents negative growth control.
C1 NATL INST MED RES,MRC,EUKARYOT MOLEC GENET LAB,RIDGEWAY,MILL HILL,LONDON NW7 1AA,ENGLAND.
   IMPERIAL CANC RES FUND,CLARE HALL LABS,POTTERS BAR EN6 3LD,HERTS,ENGLAND.
C3 MRC National Institute for Medical Research
NR 22
TC 287
Z9 300
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 249
EP 251
DI 10.1038/352249a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500069
PM 1830372
DA 2026-03-10
ER

PT J
AU JEWETT, ME
   KRONAUER, RE
   CZEISLER, CA
AF JEWETT, ME
   KRONAUER, RE
   CZEISLER, CA
TI LIGHT-INDUCED SUPPRESSION OF ENDOGENOUS CIRCADIAN AMPLITUDE IN HUMANS
SO NATURE
LA English
DT Article
ID rhythm; oscillator; induction; gonyaulax; pulses; clock
AB WINFREE reported 20 years ago the intriguing finding that a light stimulus of a critical strength applied at a critical circadian phase could essentially stop the circadian clock in Drosophila pseudo-obscura by resetting the circadian oscillator close to its singularity (a phaseless position at which the amplitude of circadian oscillation is zero) 1.  Since then, similar observations of attenuated circadian amplitude in response to critical stimuli have been limited to unicells, insects and plants 2-7.  Our recent demonstration that the phase of the human circadian pacemaker could be inverted using an unconventional three-cycle stimulus 8,9 led us to investigate whether critically timed exposure to a more moderate stimulus could drive that oscillator towards its singularity.  Here we report that exposure of humans to fewer cycles of bright light, centred around the time at which the human circadian pacemaker is most sensitive to light-induced phase shifts, can markedly attenuate endogenous circadian amplitude.  In some cases this results in an apparent loss of rhythmicity, as expected to occur in the region of singularity.
C1 HARVARD UNIV,BRIGHAM & WOMENS HOSP,SCH MED,DEPT MED,CIRCADIAN & SLEEP DISORDERS MED LAB,BOSTON,MA 02115.
   HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138.
C3 Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University
NR 18
TC 213
Z9 235
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 59
EP 62
DI 10.1038/350059a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300064
PM 2002845
DA 2026-03-10
ER

PT J
AU EIGLER, DM
   LUTZ, CP
   RUDGE, WE
AF EIGLER, DM
   LUTZ, CP
   RUDGE, WE
TI AN ATOMIC SWITCH REALIZED WITH THE SCANNING TUNNELING MICROSCOPE
SO NATURE
LA English
DT Article
ID tunneling-microscope; scale; electromigration
AB THE scanning tunnelling microscope 1 (STM) has been employed in recent years in attempts to develop atomic-scale electronic devices, both by examining device-like characteristics in preexisting structures 2,3 and by creating new structures by the precise manipulation of atoms and molecules with the STM tip 4-6. Here we report the operation of a bistable switch that derives its function from the motion of a single atom. A xenon atom is moved reversibly between stable positions on each of two stationary conducting 'leads', corresponding to the STM tip and a nickel surface. The state of the switch is set (that is, the xenon atom is moved to the desired location) by the application of a voltage pulse of the appropriate sign across the leads. The state of the switch is identified by measuring the conductance across the leads. This switch is a prototype of a new class of potentially very small electronic devices which we will call atom switches.
RP EIGLER, DM (corresponding author), IBM CORP, DIV RES, ALMADEN RES CTR, 650 HARRY RD, SAN JOSE, CA 95120 USA.
NR 16
TC 711
Z9 764
U1 1
U2 216
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 600
EP 603
DI 10.1038/352600a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100047
DA 2026-03-10
ER

PT J
AU ERIKSON, J
   RADIC, MZ
   CAMPER, SA
   HARDY, RR
   CARMACK, C
   WEIGERT, M
AF ERIKSON, J
   RADIC, MZ
   CAMPER, SA
   HARDY, RR
   CARMACK, C
   WEIGERT, M
TI EXPRESSION OF ANTI-DNA IMMUNOGLOBULIN TRANSGENES IN NON-AUTOIMMUNE MICE
SO NATURE
LA English
DT Article
ID systemic lupus-erythematosus; lymphocytes-b; antibody; autoantibody; mouse; activation; genes; cells
AB SELF-REACTIVE B cells can be regulated by either deletion or inactivation 1. These manifestations of self-tolerance have been dramatically shown in transgenic mice in which the number of self-reactive cells has been artificially expanded 2,3. We have now extended these models to ask if B-cell tolerance as described for non-disease-associated antigens also operates for the targets of autoimmunity. The target we have chosen is DNA. Anti-DNA antibodies are diagnostic of certain autoimmune syndromes in humans and are a characteristic of the murine model of systemic autoimmunity, the MRI/Ipr mouse4. Antibodies to both single-stranded and double-stranded DNA have been implicated in disease 5,6. By generating anti-DNA transgenic mice, we have addressed the question of whether DNA-specific B cells are regulated in normal (non-autoimmune) mice. We indeed found that most transgenic B cells bind DNA, yet we failed to detect secreted anti-DNA. We suggest that as a consequence of their self-reactivity these B cells are developmentally arrested.
C1 UNIV MICHIGAN, SCH MED, DEPT HUMAN GENET, ANN ARBOR, MI 48109 USA.
C3 University of Michigan System; University of Michigan
RP ERIKSON, J (corresponding author), FOX CHASE CANC INST, INST CANC RES, 7701 BURHOLME AVE, PHILADELPHIA, PA 19111 USA.
NR 30
TC 458
Z9 505
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 331
EP 334
DI 10.1038/349331a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100053
PM 1898987
DA 2026-03-10
ER

PT J
AU IIJIMA, S
AF IIJIMA, S
TI HELICAL MICROTUBULES OF GRAPHITIC CARBON
SO NATURE
LA English
DT Article
ID c-60
AB THE synthesis of molecular carbon structures in the form of C60 and other fullerenes 1 has stimulated intense interest in the structures accessible to graphitic carbon sheets. Here I report the preparation of a new type of finite carbon structure consisting of needle-like tubes. Produced using an arc-discharge evaporation method similar to that used for fullerene synthesis, the needles grow at the negative end of the electrode used for the arc discharge. Electron microscopy reveals that each needle comprises coaxial tubes of graphitic sheets, ranging in number from 2 up to about 50. On each tube the carbon-atom hexagons are arranged in a helical fashion about the needle axis. The helical pitch varies from needle to needle and from tube to tube within a single needle. It appears that this helical structure may aid the growth process. The formation of these needles, ranging from a few to a few tens of nanometres in diameter, suggests that engineering of carbon structures should be possible on scales considerably greater than those relevant to the fullerenes.
RP IIJIMA, S (corresponding author), NEC CORP LTD, FUNDAMENTAL RES LABS, 34 MIYUKIGAOKA, TSUKUBA, IBARAKI 305, JAPAN.
NR 11
TC 38895
Z9 44886
U1 62
U2 6992
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 56
EP 58
DI 10.1038/354056a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900055
DA 2026-03-10
ER

PT J
AU QUON, D
   WANG, Y
   CATALANO, R
   SCARDINA, JM
   MURAKAMI, K
   CORDELL, B
AF QUON, D
   WANG, Y
   CATALANO, R
   SCARDINA, JM
   MURAKAMI, K
   CORDELL, B
TI FORMATION OF BETA-AMYLOID PROTEIN DEPOSITS IN BRAINS OF TRANSGENIC MICE
SO NATURE
LA English
DT Article
ID precursor messenger-rna; alzheimers-disease; differential expression; senile plaques; rat-brain; antibody; neurons; cortex; gene; dna
AB DEPOSITS of beta-amyloid are one of the main pathological characteristics of Alzheimer's disease. The beta-amyloid peptide constituent (relative molecular mass 4,200) of the deposits is derived from the beta-amyloid precursor protein (beta-APP) which is expressed in several different isoforms 1-6. The two most prevalent beta-APP isoforms are distinguished by either the presence (beta-APP751) or absence (beta-APP695) of a Kunitz serine protease inhibitor domain. Changes in the abundance of different beta-APP messenger RNAs in brains of Alzheimer's disease victims have been widely reported 7-12. Although these results have been controversial, most evidence favours an increase in the mRNAs encoding protease inhibitor-containing isoforms of beta-APP and it is proposed that this change contributes to beta-amyloid formation 9-12. We have now produced an imbalance in the normal neuronal ratio of beta-APP isoforms by preparing transgenic mice expressing additional beta-APP751 under the control of a neural-specific promoter. The cortical and hippocampal brain regions of the transgenic mice display extracellular beta-amyloid immunoreactive deposits varying in size (< 5-50-mu-m) and abundance. These results suggest that one mechanism of beta-amyloid formation may involve a disruption of the normal ratio of neuronal beta-APP isoform expression and support a direct relationship between increased expression of Kunitz inhibitor-bearing beta-APP isoforms and beta-amyloid deposition.
C1 CALIF BIOTECHNOL INC,2450 BAYSHORE PKWY,MT VIEW,CA 94043.
NR 30
TC 360
Z9 434
U1 0
U2 17
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 239
EP 241
DI 10.1038/352239a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500065
PM 1906990
DA 2026-03-10
ER

PT J
AU FISHMAN, GJ
   HARMON, BA
   GREGORY, JC
   PARNELL, TA
   PETERS, P
   PHILLIPS, GW
   KING, SE
   AUGUST, RA
   RITTER, JC
   CUTCHIN, JH
   HASKINS, PS
   MCKISSON, JE
   ELY, DW
   WEISENBERGER, AG
   PIERCEY, RB
   DYBLER, T
AF FISHMAN, GJ
   HARMON, BA
   GREGORY, JC
   PARNELL, TA
   PETERS, P
   PHILLIPS, GW
   KING, SE
   AUGUST, RA
   RITTER, JC
   CUTCHIN, JH
   HASKINS, PS
   MCKISSON, JE
   ELY, DW
   WEISENBERGER, AG
   PIERCEY, RB
   DYBLER, T
TI OBSERVATION OF BE-7 ON THE SURFACE OF LDEF SPACECRAFT
SO NATURE
LA English
DT Article
ID troposphere; beryllium-7; stratosphere; transport; exchange; air
AB THE Long Duration Exposure Facility (LDEF), an orbiting unmanned satellite, was recently returned to Earth after almost six years in space.  From radioactivity measurements, we have found significant quantities of the isotope Be-7 on the leading edge (but only on the leading edge) of LDEF.  Although the absolute atmospheric concentration of Be-7 needed to explain this detection is extremely small (10(-7) atoms cm-3), it concentration of LDEF's altitude (310 km) must be several orders of magnitude higher than in the stratosphere below, where it is produced by cosmic-ray reactions with atmospheric nitrogen and oxygen nuclei.  To explain the presence of Be-7 on the surface of LDEF, it must first be rapidly and efficiently transported to high altitudes, and then adsorbed onto the surface of the spacecraft.  Neither process had been expected.  Our detection may therefore lead to the use of Be-7 as an exo-atmospheric tracer, as well as to studies of surface interactions in space.
C1 UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35806.
   UNIV ALABAMA,DEPT CHEM,HUNTSVILLE,AL 35899.
   SACHS FREEMAN ASSOCIATES INC,WASHINGTON,DC 20375.
   UNIV FLORIDA,GAINESVILLE,FL 32609.
   INST SPACE SCI & TECHNOL,GAINESVILLE,FL 32609.
   MISSISSIPPI STATE UNIV,DEPT PHYS,MISSISSIPPI STATE,MS 39762.
   USN,RES LAB,WASHINGTON,DC 20375.
C3 Universities Space Research Association (USRA); University of Alabama System; University of Alabama Huntsville; State University System of Florida; University of Florida; Mississippi State University; United States Department of Defense; United States Navy; United States Naval Research Laboratory; NRL Chesapeake
RP FISHMAN, GJ (corresponding author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,CODE ES62,HUNTSVILLE,AL 35812, USA.
NR 17
TC 11
Z9 11
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 678
EP 680
DI 10.1038/349678a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700040
DA 2026-03-10
ER

PT J
AU ROSENSTEIN, Y
   PARK, JK
   HAHN, WC
   ROSEN, FS
   BIERER, BE
   BURAKOFF, SJ
AF ROSENSTEIN, Y
   PARK, JK
   HAHN, WC
   ROSEN, FS
   BIERER, BE
   BURAKOFF, SJ
TI CD43, A MOLECULE DEFECTIVE IN WISKOTT-ALDRICH SYNDROME, BINDS ICAM-1
SO NATURE
LA English
DT Article
AB THE protein CD43 (also known as sialophorin, leukosialin, large sialoglycoprotein or gp115) is expressed on the surface of T lymphocytes, monocytes, neutrophils, platelets and some B lymphocytes 1-6. Expression of CD43 is deficient and/or defective in the X-chromosome-linked immunodeficiency disorder Wiscott-Aldrich syndrome 7, suggesting that CD43 might have a role in T-cell activation. We have shown that expression of human CD43 in an HLA-DR-specific murine T-cell hybridoma enhances the antigen-specific response to stimulation by the human lymphoblastoid cell line Daudi, and that Daudi cells bind specifically to purified immobilized CD43 (ref. 8). These data indicate that the specific interaction of CD43 with a ligand on the surface of Daudi cells might contribute to T-cell activation. Here we report evidence that intercellular adhesion molecule-1 (ICAM-1, or CD54), is a ligand for CD43.
C1 HARVARD UNIV, SCH MED, DEPT PATHOL, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, DEPT PEDIAT, BOSTON, MA 02115 USA.
   BRIGHAM & WOMENS HOSP, CTR BLOOD RES, BOSTON, MA 02115 USA.
   BRIGHAM & WOMENS HOSP, DIV HEMATOL ONCOL, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, DEPT MED, BOSTON, MA 02115 USA.
C3 Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Program in Cellular & Molecular Medicine (PCMM); Brigham & Women's Hospital; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical School
RP ROSENSTEIN, Y (corresponding author), HARVARD UNIV, SCH MED, DANA FARBER CANC INST, DIV PEDIAT ONCOL, BOSTON, MA 02115 USA.
NR 33
TC 263
Z9 278
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 233
EP 235
DI 10.1038/354233a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800050
PM 1683685
DA 2026-03-10
ER

PT J
AU WEBSTER, MA
   MOLLON, JD
AF WEBSTER, MA
   MOLLON, JD
TI CHANGES IN COLOR APPEARANCE FOLLOWING POST-RECEPTORAL ADAPTATION
SO NATURE
LA English
DT Article
ID chromatic mechanisms; luminance; vision; green; blue
AB CURRENT models of colour vision assume that colour is represented by activity in three independent post-receptoral channels:  two encoding chromatic information and one encoding luminance 1.  An important feature of these models is that variations in certain directions in colour space modulate the response of only one of the channels.  We have tested whether such models can predict how colour appearance is altered by adaptation-induced changes in post-receptoral sensitivity.  In contrast to the changes predicted by three independent channels, colour appearance is always distorted away from the direction in colour space to which the observer has adapted.  This suggests that at the level at which the adaptation effects occur, there is no colour direction that invariably isolates only a single post-receptoral channel.
RP WEBSTER, MA (corresponding author), UNIV CAMBRIDGE,DEPT EXPTL PSYCHOL,CAMBRIDGE CB2 3EB,ENGLAND.
NR 24
TC 182
Z9 202
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 235
EP 238
DI 10.1038/349235a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900054
PM 1987475
DA 2026-03-10
ER

PT J
AU SIGURDSSON, H
   DHONDT, S
   ARTHUR, MA
   BRALOWER, TJ
   ZACHOS, JC
   VANFOSSEN, M
   CHANNELL, JET
AF SIGURDSSON, H
   DHONDT, S
   ARTHUR, MA
   BRALOWER, TJ
   ZACHOS, JC
   VANFOSSEN, M
   CHANNELL, JET
TI GLASS FROM THE CRETACEOUS TERTIARY BOUNDARY IN HAITI
SO NATURE
LA English
DT Article
ID impact event; raton basin; new-mexico; sm-nd; rb-sr; spherules; colorado; site; extinctions; systematics
AB Tektite-like glasses preserved at the Cretaceous/Tertiary boundary at Beloc in Haiti provide clear evidence of an impact event. The glass composition suggests that the impact occurred on a continental shelf region, generating a silica-rich glass with chemical composition that reflects the melting of continental crustal rocks, and a calcium-rich glass produced by the fusion of marl sediments. These findings indicate that catastrophic release to the atmosphere of 10(15) moles of CO2 from vaporized marl occurred during the impact.
C1 UNIV N CAROLINA, CHAPEL HILL, NC 27599 USA.
   UNIV MICHIGAN, ANN ARBOR, MI 48109 USA.
   UNIV FLORIDA, GAINESVILLE, FL 32611 USA.
C3 University of North Carolina; University of North Carolina Chapel Hill; University of Michigan System; University of Michigan; State University System of Florida; University of Florida
RP SIGURDSSON, H (corresponding author), UNIV RHODE ISL, GRAD SCH OCEANOG, NARRAGANSETT, RI 02882 USA.
NR 45
TC 179
Z9 185
U1 0
U2 11
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 482
EP 487
DI 10.1038/349482a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100054
DA 2026-03-10
ER

PT J
AU KANAMORI, H
   MORI, J
   ANDERSON, DL
   HEATON, TH
AF KANAMORI, H
   MORI, J
   ANDERSON, DL
   HEATON, TH
TI SEISMIC EXCITATION BY THE SPACE-SHUTTLE COLUMBIA
SO NATURE
LA English
DT Article
AB SEISMIC stations in southern California recorded the atmospheric shock waves generated by the space shuttle Columbia on its return to the Edwards Air Force base on 13 August 1989 (Fig. 1).  In addition to the shock wave, the broad-band IRIS-TERRAscope station at Pasadena recorded a distinct pulse with a period of approximately 2-3 seconds, which arrived 12.5 seconds before the shock wave (Fig. 2).  This pulse was also recorded at the University of Southern California, near downtown Los Angeles, where it arrived 3 seconds after the shock wave.  The origin of this pulse could not be readily identified.  We show here that it was a seismic P wave excited by the motion of high-rise buildings in downtown Los Angeles, which were hit by the shock wave.  The proximity of the natural period of the high-rise buildings to that of the Los Angeles basin enabled efficient energy transfer from shock wave to seismic wave.
C1 US GEOL SURVEY,PASADENA,CA 91106.
C3 United States Department of the Interior; United States Geological Survey
RP KANAMORI, H (corresponding author), CALTECH,SEISMOL LAB,PASADENA,CA 91125, USA.
NR 9
TC 85
Z9 92
U1 1
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 781
EP 782
DI 10.1038/349781a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600052
DA 2026-03-10
ER

PT J
AU CHEN, MS
   OBAR, RA
   SCHROEDER, CC
   AUSTIN, TW
   POODRY, CA
   WADSWORTH, SC
   VALLEE, RB
AF CHEN, MS
   OBAR, RA
   SCHROEDER, CC
   AUSTIN, TW
   POODRY, CA
   WADSWORTH, SC
   VALLEE, RB
TI MULTIPLE FORMS OF DYNAMIN ARE ENCODED BY SHIBIRE, A DROSOPHILA GENE INVOLVED IN ENDOCYTOSIS
SO NATURE
LA English
DT Article
ID mechanochemical enzyme; microtubules; melanogaster; proteins; identification; translocation; expression; sequence; cloning; mutant
AB DYNAMIN was discovered in bovine brain tissue as a nucleotide-sensitive microtubule-binding protein of relative molecular mass 100,000 1. It was found to cross-link microtubules into highly ordered bundles, and appeared to have a role in intermicrotubule sliding in vitro. Cloning and sequencing of rat brain dynamin complementary DNA identified an N-terminal region of about 300 amino acids which contained the three consensus elements characteristic of GTP-binding proteins 2. Extensive homology was found between this domain and the mammalian Mx proteins which are involved in interferon-induced viral resistance 3,4, and with the product of the VPS1 locus in Saccharomyces cerevisiae, which has been implicated both in membrane protein sorting 5, and in meiotic spindle pole separation 6. Dynamin-containing microtubule bundles were not observed in an immunofluorescence study of cultured mammalian cells 7, but a role for a GTP-requiring protein in intermicrotubule sliding during mitosis in plants has been reported 8. We report here that Drosophila melanogaster contains multiple tissue-specific and developmentally-regulated forms of dynamin, which are products of the shibire locus previously implicated in endocytic protein sorting 9,10.
C1 WORCESTER FDN EXPTL BIOL INC, CELL BIOL GRP, SHREWSBURY, MA 01545 USA.
   UNIV CALIF SANTA CRUZ, DEPT BIOL, SANTA CRUZ, CA 95064 USA.
C3 Worcester Foundation for Biomedical Research; University of California System; University of California Santa Cruz
NR 26
TC 497
Z9 551
U1 0
U2 29
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 583
EP 586
DI 10.1038/351583a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400064
PM 1828536
DA 2026-03-10
ER

PT J
AU HARBURN, G
   TILLEY, RJD
   WILLIAMS, JM
   WILLIAMS, RP
AF HARBURN, G
   TILLEY, RJD
   WILLIAMS, JM
   WILLIAMS, RP
TI A LATTICE-LIKE CONSTRUCTION TO EXPLAIN DIFFRACTION PATTERNS OF SOME NONSTOICHIOMETRIC PHASES
SO NATURE
LA English
DT Article
AB One of the most significant advances in the understanding of non-stoichiometric compounds was Anderson's concept of infinitely adaptive structures 1.  These materials exhibit a continuum of perfectly ordered structures as the stoichiometry is varied.  X-ray crystallography has not yielded satisfactory structures for these phases, and high-resolution electron microscopy has also been unable to unravel the difficulties.  To try to resolve these problems, we have focused our attention on the nature of the diffraction patterns that the compounds produce.  We find that in many cases the diffraction patterns can be reproduced by the use of lattice-like constructions which we term shift lattices.  Here we describe the method of construction of a one-dimensional shift lattice and mathematical representations of it and its Fourier transform.  The method has wide applicability to complex structures, of which we have investigated several examples:  the low-temperature tantalum pentoxide (L-Ta2O5) family of structures, Bi2TeO5-related phases in the Bi2O3-TeO2 system and a number of non-stoichiometric heavy-metal oxyfluoride phases.  For simplicity, we limit ourselves to a consideration of the one-dimensional case which we illustrate by reference to L-Ta2O5; nevertheless, all the examples that we have considered are explicable by such one-dimensional shift lattices.
C1 UNIV WALES COLL CARDIFF,SCH ENGN,DIV MAT,CARDIFF CF2 1XH,WALES.
C3 Cardiff University
RP HARBURN, G (corresponding author), UNIV WALES COLL CARDIFF,SCH ENGN,DEPT PHYS,POB 917,CARDIFF CF2 1XH,WALES.
NR 3
TC 8
Z9 8
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 214
EP 216
DI 10.1038/350214a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900050
DA 2026-03-10
ER

PT J
AU AYERS, GP
   IVEY, JP
   GILLETT, RW
AF AYERS, GP
   IVEY, JP
   GILLETT, RW
TI COHERENCE BETWEEN SEASONAL CYCLES OF DIMETHYL SULFIDE, METHANESULFONATE AND SULFATE IN MARINE AIR
SO NATURE
LA English
DT Article
ID continental sources; pacific-ocean; sulfur; kinetics; sulfate; sulfide
AB THE effect of cloud condensation nuclei (CCN) in controlling cloud albedo and hence global climate has prompted questions about the factors that control CCN populations.  Charlson et al. 1 suggested that marine phytoplankton might control CCN populations.  The effect would be strongest over the oceans, where low stratiform clouds are common, and CCN are composed mostly of ammonium sulphate believed to be produced by atmospheric oxidation of gaseous dimethyl sulphide (DMS) emitted by phytoplankton,  Here we present twenty months of data from a clean marine site at 40-degrees-S, which confirm the connection between atmospheric DMS and aerosol sulphur species that is central to the hypothesis of Charlson et al. 1.  The relationships between DMS, aerosol sulphate and CCN are nonlinear, implying that at this site there would be significant nonlinearities in the climate feedback mechanism.  In addition, our data on atmospheric sulphur species show a strong seasonal cycle, indicating that it should be possible to look for large, natural, seasonal variations in cloud albedo as a rigorous test of the Charlson et al. hypothesis.
C1 AUSTRALIAN GOVT ANALYT LABS,KINGSTON 7051,AUSTRALIA.
C3 National Measurement Institute Australia - NMI
RP AYERS, GP (corresponding author), CSIRO,DIV ATMOSPHER RES,PRIVATE BAG 1,MORDIALLOC 3195,AUSTRALIA.
NR 24
TC 257
Z9 268
U1 0
U2 42
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 404
EP 406
DI 10.1038/349404a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400046
DA 2026-03-10
ER

PT J
AU RAABE, T
   BOLLUM, FJ
   MANLEY, JL
AF RAABE, T
   BOLLUM, FJ
   MANLEY, JL
TI PRIMARY STRUCTURE AND EXPRESSION OF BOVINE POLY(A) POLYMERASE
SO NATURE
LA English
DT Article
ID messenger-rna precursors; sulfate-polyacrylamide gels; 3' untranslated region; sodium dodecyl-sulfate; hela-cells; binding proteins; polyadenylation; sequence; cleavage; identification
AB Poly(A) polymerase has a critical role in the synthesis of messenger RNA in eukaryotic cells. The isolation and characterization of complementary DNAs encoding bovine poly(A) polymerase is described here. The predicted sequences of the MRNA and protein reveal features that provide insights into how the enzyme functions and how it might be regulated. Poly(A) polymerase expressed from a cloned cDNA is fully functional in in vitro assays, and mutational analyses have identified a putative regulatory domain that enhances, but is not essential for, activity.
C1 UNIFORMED SERV UNIV HLTH SCI,DEPT BIOCHEM,BETHESDA,MD 20814.
C3 Uniformed Services University of the Health Sciences - USA
RP RAABE, T (corresponding author), COLUMBIA UNIV,DEPT BIOL SCI,NEW YORK,NY 10027, USA.
NR 51
TC 143
Z9 158
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 229
EP 234
DI 10.1038/353229a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400049
PM 1896071
DA 2026-03-10
ER

PT J
AU MORIN, GB
AF MORIN, GB
TI RECOGNITION OF A CHROMOSOME TRUNCATION SITE ASSOCIATED WITH ALPHA-THALASSEMIA BY HUMAN TELOMERASE
SO NATURE
LA English
DT Article
ID terminal transferase-activity; protozoan oxytricha-nova; macronuclear dna; tetrahymena; sequences; breakage; ribonucleoprotein; identification; deletions; repeats
AB TELOMERES define the ends of chromosomes; they consist of short tandemly repeated DNA sequences loosely conserved in eukaryotes (G1-8(T/A)1-4) 1.  Telomerase is a ribonucleoprotein which, in vitro, recognizes a single-stranded G-rich telomere primer and adds multiple telomeric repeats to its 3' end by using a template in the RNA moiety 2-6.  In conjunction with other components, telomerase may balance the loss of telomeric repeats due to DNA replication 7.  Another role of telomerase may be the de novo formation of telomeres.  In eukaryotes like Tetrahymena, this process is an integral part of the formation of macronuclear chromosomes 8.  In other eukaryotes this process stabilizes broken chromosomes.  A case of human alpha-thalassaemia is caused by a truncation of chromosome 16 that has been healed by the addition of telomeric repeats (TTAGGG)n (ref. 9).  Using an in vitro assay 4, I show here that human telomerase correctly recognizes the chromosome 16 breakpoint sequence and adds (TTAGGG)n repeats.  The DNA sequence requirements are minimal and seem to define two modes of DNA recognition by telomerase.
C1 YALE UNIV,HOWARD HUGHES MED INST,DEPT MOLEC BIOPHYS & BIOCHEM,NEW HAVEN,CT 06510.
C3 Howard Hughes Medical Institute; Yale University
NR 31
TC 198
Z9 219
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 454
EP 456
DI 10.1038/353454a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600065
PM 1896089
DA 2026-03-10
ER

PT J
AU KIM, JW
   CLOSS, EI
   ALBRITTON, LM
   CUNNINGHAM, JM
AF KIM, JW
   CLOSS, EI
   ALBRITTON, LM
   CUNNINGHAM, JM
TI TRANSPORT OF CATIONIC AMINO-ACIDS BY THE MOUSE ECOTROPIC RETROVIRUS RECEPTOR
SO NATURE
LA English
DT Article
ID cultured animal-cells; glucose transporter; mammalian-cells; rat-liver; gene; membrane; protein; system; histidine; promoter
AB SUSCEPTIBILITY of rodent cells to infection by ecotropic murine leukaemia viruses (MuLV) is determined by binding of the virus envelope to a membrane receptor that has multiple membrane-spanning domains 1.  Cells infected by ecotropic MuLV synthesize envelope protein, gp70, which binds to this receptor, thereby preventing additional infections. The consequences of envelope-MuLV receptor binding for the infected host cell have not been directly determined, partly because the cellular function of the MuLV receptor protein is unknown. Here we report a coincidence in the positions of the first eight putative membrane-spanning domains found in the virus receptor 1 and in two related proteins 2, the arginine 2-4 and histidine 2,3,5 permeases of Saccharomyces cerevisiae (Fig. 1), but not in any other proteins identified by computer-based sequence comparison of the GenBank data base 1. Xenopus oocytes injected with receptor-encoding messenger RNA show increased uptake of L-arginine, L-lysine and L-ornithine. The transport properties and the expression pattern of the virus receptor behave in ways previously attributed to y+ (refs 6, 7), the principal transporter of cationic L-amino acids in mammalian cells.
C1 BRIGHAM & WOMENS HOSP,HOWARD HUGHES MED INST,75 FRANCIS ST,BOSTON,MA 02115.
   BRIGHAM & WOMENS HOSP,DEPT MED,DIV HEMATOL,BOSTON,MA 02115.
   HARVARD UNIV,SCH MED,BOSTON,MA 02115.
C3 Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Howard Hughes Medical Institute; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical School
NR 29
TC 502
Z9 555
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 725
EP 728
DI 10.1038/352725a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400062
PM 1652100
DA 2026-03-10
ER

PT J
AU HAYAKAWA, S
AF HAYAKAWA, S
TI A HOT GAS-MODEL FOR IRON-LINE X-RAY-EMISSION FROM THE RAPIDLY VARYING SEYFERT-GALAXY NGC6814
SO NATURE
LA English
DT Article
AB KUNIEDA et al. 1 have observed rapidly varying X-ray continuum emission, along with an emission line at 6.4 keV, from the Seyfert I galaxy NGC6814.  They suggest that a central energy source of radius approximately 10(12) cm generates X-rays that produce the emission line by fluorescence of iron in a surrounding cold gas, which extends out to approximately 10(13) cm.  But in this model the intense X-irradiation needed to explain the line intensity would heat the surrounding gas to too high a temperature to allow the existence of the low ionization state needed to account for the wavelength of the line.  I argue here, therefore, that the line is generated by hot gas, closer to the central energy source, and that the observed wavelength corresponds to the energy of a higher ionization state of iron, gravitationally redshifted by approximately 6%.
RP HAYAKAWA, S (corresponding author), NAGOYA UNIV,FURO CHO,CHIKUSA KU,NAGOYA 46401,JAPAN.
NR 6
TC 10
Z9 10
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 214
EP 215
DI 10.1038/351214a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000049
DA 2026-03-10
ER

PT J
AU HEBARD, AF
   ROSSEINSKY, MJ
   HADDON, RC
   MURPHY, DW
   GLARUM, SH
   PALSTRA, TTM
   RAMIREZ, AP
   KORTAN, AR
AF HEBARD, AF
   ROSSEINSKY, MJ
   HADDON, RC
   MURPHY, DW
   GLARUM, SH
   PALSTRA, TTM
   RAMIREZ, AP
   KORTAN, AR
TI SUPERCONDUCTIVITY AT 18-K IN POTASSIUM-DOPED C-60
SO NATURE
LA English
DT Article
AB THE synthesis of macroscopic amounts of C60 and C70 (fullerenes) 1 has stimulated a variety of studies on their chemical and physical properties 2,3.  We recently demonstrated that C60 and C70 become conductive when doped with alkali metals 4.  Here we describe low-temperature studies of potassium-doped C60 both as films and bulk samples, and demonstrate that this material becomes superconducting.  Superconductivity is demonstrated by microwave, resistivity and Meissner-effect measurements.  Both polycrystalline powders and thin-film samples were studied.  A thin film showed a resistance transition with an onset temperature of 16 K and essentially zero resistance near 5 K.  Bulk samples showed a well-defined Meissner effect and magnetic-field-dependent microwave absorption beginning at 18 K.  The onset of superconductivity at 18 K is the highest yet observed for a molecular superconductor.
RP HEBARD, AF (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 6
TC 2848
Z9 2972
U1 6
U2 523
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 600
EP 601
DI 10.1038/350600a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200056
DA 2026-03-10
ER

PT J
AU CLEMENS, S
   PRELL, W
   MURRAY, D
   SHIMMIELD, G
   WEEDON, G
AF CLEMENS, S
   PRELL, W
   MURRAY, D
   SHIMMIELD, G
   WEEDON, G
TI FORCING MECHANISMS OF THE INDIAN-OCEAN MONSOON
SO NATURE
LA English
DT Article
ID long-term variations; eurasian snow cover; arabian sea; summer 1975; planktonic-foraminifera; surface sediments; ice ages; transport; variability; insolation
AB Sediments in the Arabian Sea provide biological, biogeochemical and lithogenic evidence of past changes in the Indian Ocean summer monsoon winds. For the past 350,000 years, this system has been externally forced by cyclical changes in solar radiation, and internally phase-locked to the transport of latent heat from the southern subtropical Indian Ocean to the Tibetan Plateau. In contrast to the results of general circulation models, these geological data suggest that the climate change associated with variability in global ice volume is not a primary factor in determining the strength and timing of the monsoon winds.
C1 UNIV EDINBURGH,EDINBURGH EH9 3JW,SCOTLAND.
   UNIV CAMBRIDGE,CAMBRIDGE CB2 3EQ,ENGLAND.
C3 University of Edinburgh; University of Cambridge
RP CLEMENS, S (corresponding author), BROWN UNIV,PROVIDENCE,RI 02912, USA.
NR 51
TC 569
Z9 655
U1 2
U2 81
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 24
PY 1991
VL 353
IS 6346
BP 720
EP 725
DI 10.1038/353720a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GL696
UT WOS:A1991GL69600056
DA 2026-03-10
ER

PT J
AU NUNNARI, JM
   ZIMMERMAN, DL
   OGG, SC
   WALTER, P
AF NUNNARI, JM
   ZIMMERMAN, DL
   OGG, SC
   WALTER, P
TI CHARACTERIZATION OF THE ROUGH ENDOPLASMIC-RETICULUM RIBOSOME-BINDING ACTIVITY
SO NATURE
LA English
DT Article
ID microsomal-membranes; identification; translocation; proteins
AB THE rough endoplasmic reticulum membranes of mammalian cells contain specific ribosome-binding sites 1. A purification to apparent homogeneity of a negatively charged protein (ERpl80) of relative molecular mass 180,000 (180 K) was reported which was proposed to function as a rough endoplasmic reticulum ribosome receptor 2 We report here that ribosome-binding site activity quantitatively solubilized from rough endoplasmic reticulum membranes does not cofractionate with ERpl80. By contrast, ribosome-binding site activity fractionates as a much smaller, positively charged protein.
RP NUNNARI, JM (corresponding author), UNIV CALIF SAN FRANCISCO,SCH MED,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143, USA.
NR 8
TC 31
Z9 33
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 638
EP 640
DI 10.1038/352638a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100061
PM 1650916
DA 2026-03-10
ER

PT J
AU ITTEKKOT, V
   NAIR, RR
   HONJO, S
   RAMASWAMY, V
   BARTSCH, M
   MANGANINI, S
   DESAI, BN
AF ITTEKKOT, V
   NAIR, RR
   HONJO, S
   RAMASWAMY, V
   BARTSCH, M
   MANGANINI, S
   DESAI, BN
TI ENHANCED PARTICLE FLUXES IN BAY OF BENGAL INDUCED BY INJECTION OF FRESH-WATER
SO NATURE
LA English
DT Article
ID deep-ocean; sediment traps; rates
AB THE melting of ice sheets during deglaciation results in the injection of large amounts of fresh water into the oceans 1. To investigate how such injections might influence particle fluxes in the ocean, and hence the uptake of atmospheric CO2, we deployed three sediment-trap moorings (two traps in each mooring) in the northern, central and southern parts of the Bay of Bengal, respectively.  The Bay of Bengal is suitable for such a study, because some of the world's largest rivers 2 supply pulses of fresh water and sediment to the bay, resulting in large seasonal changes in surface salinity 3.  We find that the maximum river discharge, which occurs during the southwest monsoon, coincides with the maximum observed flux of particulate matter.  From north to south, the carbonate flux increases, whereas fluxes of opal, organic carbon and particulate matter decrease. The overall flux pattern seems to be controlled by the seasonally varying input from the rivers and the accompanying shift in marine biogenic production.  We conclude that freshwater pulses during deglaciation may therefore have caused similar shifts in marine biogenic production, resulting in short-term episodes of increased oceanic uptake of atmospheric CO2.
C1 NATL INST OCEANOG,PANAJI 403004,GOA,INDIA.
   WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543.
C3 Council of Scientific & Industrial Research (CSIR) - India; CSIR - National Institute of Oceanography (NIO); Woods Hole Oceanographic Institution
RP ITTEKKOT, V (corresponding author), UNIV HAMBURG,INST BIOGEOCHEM & MARINE CHEM,BUNDESSTR 55,W-2000 HAMBURG 13,GERMANY.
NR 20
TC 215
Z9 223
U1 0
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 385
EP 387
DI 10.1038/351385a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600051
DA 2026-03-10
ER

PT J
AU HIPSKIND, RA
   RAO, VN
   MUELLER, CGF
   REDDY, ESP
   NORDHEIM, A
AF HIPSKIND, RA
   RAO, VN
   MUELLER, CGF
   REDDY, ESP
   NORDHEIM, A
TI ETS-RELATED PROTEIN ELK-1 IS HOMOLOGOUS TO THE C-FOS REGULATORY FACTOR P62TCF
SO NATURE
LA English
DT Article
ID serum response element; long terminal repeat; ternary complex; chromosome-x; dna-binding; transcription; translocation; stimulation; sequence; sarcoma
AB A KEY event in the response of cells to proliferative signals is the rapid, transient induction of the c-fos proto-oncogene, which is mediated through the serum response element (SRE) in the fos promoter 1-4.  Genomic footprinting 5,6 and transfection experiments 7-9 suggest that this activation occurs through a ternary complex that includes the serum response factor (SRF) 10 and the ternary complex factor p62 (ref. 7). Interaction of p62TCF with the SRF-SRE binary complex requires a CAGGA tract immediately upstream of the SRE (ref. 7). Proteins of the ets proto-oncogene family bind to similar sequences 11-13 and we have found that a member of this family, Elk-1 (ref. 14), forms SRF-dependent ternary complexes with the SRE. Elk-1 and p62TCF have the same DNA sequence requirements and antibodies against Elk-1 block the binding of both proteins. Furthermore, we show that like P62TCF, Elk-1 forms complexes with the yeast SRF-homologue MCM1 but not with yeast ARG80 (ref. 15). But ARG80 mutants that convey interaction with p62TCF can also form complexes with Elk-1. The similarity, or even identity, between Elk-1 and p62TCF suggests a novel regulatory role for Ets proteins that is effected through interaction with other proteins, such as SRF. Furthermore, the possible involvement of an Ets protein in the control of c-fos has interesting implications for proto-oncogene cooperation in cellular growth control 16.
C1 HANOVER MED SCH,INST MOLEC BIOL,POB 610180,W-3000 HANNOVER 61,GERMANY.
   JEFFERSON CANC INST,PHILADELPHIA,PA 19107.
C3 Hannover Medical School; Thomas Jefferson University
NR 25
TC 417
Z9 438
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 531
EP 534
DI 10.1038/354531a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100017
PM 1722028
DA 2026-03-10
ER

PT J
AU SHIBUTANI, S
   TAKESHITA, M
   GROLLMAN, AP
AF SHIBUTANI, S
   TAKESHITA, M
   GROLLMAN, AP
TI INSERTION OF SPECIFIC BASES DURING DNA-SYNTHESIS PAST THE OXIDATION-DAMAGED BASE 8-OXODG
SO NATURE
LA English
DT Article
ID polymerase-delta; calf thymus; 8-hydroxy-2'-deoxyguanosine
AB OXIDATIVE damage to DNA, reflected in the formation of 8-oxo-7-hydrodeoxyguanosine (8-oxodG) 1, 2, may be important in mutagenesis, carcinogenesis and the ageing process 3,4.  Kuchino et al. studied DNA synthesis on oligodeoxynucleotide templates containing 8-oxodG, concluding that the modified base lacked base pairing specificity and directed misreading of pyrimidine residues neighbouring the lesion 5.  Here we report different results, using an approach in which the several products of a DNA polymerase reaction can be measured. In contrast to the earlier report 5, we find that dCMP and dAMP are incorporated selectively opposite 8-oxodG with transient inhibition of chain extension occurring 3' to the modified base.  The potentially mutagenic insertion of dAMP is targeted exclusively to the site of the lesion.  The ratio of dCMP to dAMP incorporated varies, depending on the DNA polymerase involved.  Chain extension from the dA . 8-oxodG pair was efficiently catalysed by all polymerases tested.
RP SHIBUTANI, S (corresponding author), SUNY STONY BROOK,DEPT PHARMACOL SCI,STONY BROOK,NY 11794, USA.
NR 23
TC 2147
Z9 2363
U1 1
U2 87
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 431
EP 434
DI 10.1038/349431a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400057
PM 1992344
DA 2026-03-10
ER

PT J
AU WOLSZCZAN, A
AF WOLSZCZAN, A
TI A NEARBY 37.9-MS RADIO PULSAR IN A RELATIVISTIC BINARY-SYSTEM
SO NATURE
LA English
DT Article
ID x-ray binary; psr 1913+16; evolutionary history; stars
AB WITH very few exceptions 1, high Galactic latitudes have not been surveyed with sufficient sensitivity to detect millisecond pulsars. Accordingly we have conducted a preliminary sensitive survey at Galactic latitudes b greater-than-or-equal-to 30-degrees using the Arecibo 305-m radiotelescope at a frequency of 430 MHz.  Here I report the discovery of a 37.9-ms radio pulsar, PSR1534 + 12, in a 10.1-hour eccentric binary orbit 2.  Timing analysis constrains the masses of the pulsar and its companion to be 1.32 +/- 0.03 M. and 1.36 +/- 0.03 M. (where M. is the mass of the Sun).  This, together with the high eccentricity (e = 0.274) and small orbital diameter (approximately 2 R.), indicates that the companion is probably another neutron star, and that the orbital evolution is strongly influenced by effects due to general relativity. The exceptionally high timing accuracy obtainable in PSR1534 + 12, because the pulse is so strong and narrow, will allow general relativity to be tested with unprecedented accuracy.  The unique morphology of the pulsar's emission and polarization will  make possible the measurement of a previously unconfirmed relativistic effect, the geodetic precession of the pulsar spin-axis.
RP WOLSZCZAN, A (corresponding author), ARECIBO OBSERV,ARECIBO,PR 00613, USA.
NR 21
TC 230
Z9 240
U1 0
U2 2
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 688
EP 690
DI 10.1038/350688a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000053
DA 2026-03-10
ER

PT J
AU HELFFRICH, G
   BRODHOLT, J
AF HELFFRICH, G
   BRODHOLT, J
TI RELATIONSHIP OF DEEP SEISMICITY TO THE THERMAL STRUCTURE OF SUBDUCTED LITHOSPHERE
SO NATURE
LA English
DT Article
ID focus earthquakes; spinel transitions; slabs; transformation; parameters; rheology
AB RECENT experimental work on silicate olivine polymorphs 1 has confirmed earlier observations of mechanical failure in analogous compounds 2,3 as a result of phase transformations when nonhydrostatic stresses were applied to a metastable phase. This 'transformational faulting' 4 mechanism is considered to be a leading candidate 5, among others involving olivine transformation 6,7, for the cause of deep earthquakes. Evidence consistent with this mechanism comes from the observation 2-4 that, worldwide, earthquakes become more numerous with increasing depth after a seismicity minimum at about 350 km depth 8.  This depth lies within the range anticipated for mineralogical transformations in the subducted lithosphere 9.  But individual subduction zones differ in their thermal structures, so if transformational faulting indeed contributes to deep seismicity, this should be reflected in the location of the seismicity minimum for each zone. The depth at which the minimum occurs should depend on temperature in the same way as do the polymorphic transformations of olivine, and should always lie deeper than the depth at which the equilibrium transformation takes place. Here we test these predictions for eight subduction zones worldwide. We find that, with one exception (the North Japan zone), the depth of the seismicity minimum decreases linearly with increasing thermal age of the slab (a measure of its temperature profile). These results support the proposal that deep earthquakes are a consequence of phase transformations in olivine.
C1 UNIV BRISTOL,DEPT GEOL,BRISTOL BS8 1RJ,ENGLAND.
C3 University of Bristol
NR 24
TC 34
Z9 39
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 252
EP 255
DI 10.1038/353252a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400057
DA 2026-03-10
ER

PT J
AU JACOB, J
   KELSOE, G
   RAJEWSKY, K
   WEISS, U
AF JACOB, J
   KELSOE, G
   RAJEWSKY, K
   WEISS, U
TI INTRACLONAL GENERATION OF ANTIBODY MUTANTS IN GERMINAL-CENTERS
SO NATURE
LA English
DT Article
ID b-cell lineages; immune-response; somatic hypermutation; primary immunization; memory; amplification; polymerase; fidelity; mice; np
AB THE generation and selection of somatic antibody mutants are key elements of acquired immunity, essential for the affinity maturation of antibody responses dependent on T cells. The mutants are generated through a mechanism that introduces point mutations at high rate into rearranged variable (V) region genes in the course of cell proliferation 1,2. Their appearance coincides with the generation of germinal centres, which are characterized by oligoclonal B-cell proliferation 3,4 and have been suggested to be the microenvironment in which antibody mutants are generated 5,6. We report here direct evidence for this hypothesis. Rearranged V-region genes were amplified from the genomic DNA of cells picked from individual germinal centres. The sequence analysis of these genes revealed that most represent cells of distinct B-cell clones which expanded locally, generating somatic antibody mutants at high rate. By contrast, antigen-induced proliferation of B cells at another site, periarteriolar lymphocyte sheath-associated foci, was not associated with somatic hypermutation.
C1 UNIV COLOGNE,INST GENET,W-5000 COLOGNE 41,GERMANY.
C3 University of Cologne
RP JACOB, J (corresponding author), UNIV MARYLAND,SCH MED,DEPT MICROBIOL & IMMUNOL,BALTIMORE,MD 21201, USA.
NR 23
TC 952
Z9 1095
U1 1
U2 34
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 389
EP 392
DI 10.1038/354389a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100050
PM 1956400
DA 2026-03-10
ER

PT J
AU CHAPPELL, J
   POLACH, H
AF CHAPPELL, J
   POLACH, H
TI POSTGLACIAL SEA-LEVEL RISE FROM A CORAL RECORD AT HUON PENINSULA, PAPUA-NEW-GUINEA
SO NATURE
LA English
DT Article
ID calibration; growth; rates; reef
AB Dating of coral reef terraces can provide a record of changes in sea level, which should be pronounced during the transition between glacial and interglacial periods.  Cores drilled from coral reefs at Barbados in the equatorial west Atlantic 1 have revealed the sea-level changes that occurred during the Younger Dryas event at the end of the Last Glacial Maximum (approximately 11,000 yr BP).  It has not been known, however, whether Pacific coral reefs can grow at a rate sufficient to keep up with the rise in sea level during such a transition.  Here we report results obtained from a 52-m drill core from the post-glacial reef at Huon Peninsula, Papua New Guinea, spanning the interval from 7,000 to 11,000 C-14 yr BP, which shows that coral growth kept pace while the relative sea level rose by 50 m.  Although the tectonic environment is very different from that at Barbados, the two records compare well when corrections are made for local tectonic uplift, showing that sea-level rise was similar at both locations.  The rate of rise was greatest between 9,000 and 10,000 C-14 yr BP, corresponding to the time of the Younger Dryas.
C1 AUSTRALIAN NATL UNIV,RES SCH PACIFIC STUDIES,DEPT GEOMORPHOL,CANBERRA,ACT 2601,AUSTRALIA.
   AUSTRALIAN NATL UNIV,RES SCH PACIFIC STUDIES,RADIOCARBON DATING LAB,CANBERRA,ACT 2601,AUSTRALIA.
C3 Australian National University; Australian National University
RP CHAPPELL, J (corresponding author), AUSTRALIAN NATL UNIV,RES SCH PACIFIC STUDIES,DEPT BIOGEOG,GPO BOX 4,CANBERRA,ACT 2601,AUSTRALIA.
NR 11
TC 243
Z9 272
U1 0
U2 55
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 147
EP 149
DI 10.1038/349147a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800054
DA 2026-03-10
ER

PT J
AU IWAMOTO, M
   MAJIMA, Y
   NARUSE, H
   NOGUCHI, T
   FUWA, H
AF IWAMOTO, M
   MAJIMA, Y
   NARUSE, H
   NOGUCHI, T
   FUWA, H
TI GENERATION OF MAXWELL DISPLACEMENT CURRENT ACROSS AN AZOBENZENE MONOLAYER BY PHOTOISOMERIZATION
SO NATURE
LA English
DT Article
ID langmuir-blodgett films; air-water-interface; behavior
AB INTEREST in the behaviour of Langmuir-Blodgett (LB) films 1 is motivated by possible applications that include molecular electronics, biosensors and modelling of biological membranes. We recently 2-5 reported an electrical technique that allows molecular motions in LB films to be probed by measuring the Maxwell displacement current 6 generated across electrodes above and below the film: this current results from changes in the orientation of the molecular dipoles. Here we use the technique to study the effect of photoisomerization in an LB film consisting of an azobenzene derivative, which can be switched photochemically between cis and trans isomers. Films of this sort are of particular interest because of their possible use in information-storage devices 7-11. Successive isomerizations induced by irradiation with ultraviolet and visible light produced transient displacement-current pulses between the electrodes. We anticipate that this technique will become widely used for dynamical studies of LB films.
RP IWAMOTO, M (corresponding author), TOKYO INST TECHNOL,DEPT PHYS ELECTR,2-12-1 OOKAYAMA,MEGURO KU,TOKYO 152,JAPAN.
NR 16
TC 129
Z9 132
U1 0
U2 24
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 645
EP 647
DI 10.1038/353645a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200064
DA 2026-03-10
ER

PT J
AU JAGO, BC
   GITTINS, J
AF JAGO, BC
   GITTINS, J
TI THE ROLE OF FLUORINE IN CARBONATITE MAGMA EVOLUTION
SO NATURE
LA English
DT Article
ID oldoinyo-lengai; tanzania; lava
AB CARBONATITE magmas require some agent in solution to maintain them in the liquid state at geologically relevant temperatures and pressures1. Although the liquidus temperatures of carbonate systems are greatly lowered in the presence of water2, an unrealistically large water content (approximately 95 wt%) is required for maximum lowering of the minimum melting temperature2.  Here we report experimental results which show that, in several carbonate systems, approximately 8 wt% fluorine lowers the minimum melting and liquids temperatures to a similar extent as do these very large amounts of water.  Thus, although water may well be present in most carbonatite magmas, it is neither the only nor necessarily the main agent by which they can remain liquid.  Fluorine has the further effect of breaking the 'thermal barrier' imposed by the nyerereite composition in the system Na2CO3-K2CO3-CaCO3, thereby allowing a low-alkali calcitic carbonatite magma to differentiate into a highly sodic carbonatite magma of the Oldoinyo Lengai type.  Although this neither proves nor disproves a possible origin by liquid immiscibility, it restores the credibility of fractional crystallization as an important process in developing an alkali enrichment trend in carbonatites.
RP JAGO, BC (corresponding author), UNIV TORONTO,DEPT GEOL,TORONTO M5S 3B1,ONTARIO,CANADA.
NR 12
TC 101
Z9 113
U1 0
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 56
EP 58
DI 10.1038/349056a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100048
DA 2026-03-10
ER

PT J
AU KESKES, N
   CAMYPEYRET, J
AF KESKES, N
   CAMYPEYRET, J
TI IMAGE-PROCESSING AS A TOOL FOR INTERPRETING 3D AND 2D SEISMIC DATA
SO NATURE
LA English
DT Article
AB This article examines the application of computerised image processing techniques to the interpretation of 3D and 2D  seismic data in oil exploration and production.
RP KESKES, N (corresponding author), SOC NATL ELF AQUITAINE,CSTJF 64018,AVE LARRIBAU,PAU,FRANCE.
NR 3
TC 1
Z9 1
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 6
EP 7
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100005
DA 2026-03-10
ER

PT J
AU LUNDSTROM, I
   ERLANDSSON, R
   FRYKMAN, U
   HEDBORG, E
   SPETZ, A
   SUNDGREN, H
   WELIN, S
   WINQUIST, F
AF LUNDSTROM, I
   ERLANDSSON, R
   FRYKMAN, U
   HEDBORG, E
   SPETZ, A
   SUNDGREN, H
   WELIN, S
   WINQUIST, F
TI ARTIFICIAL OLFACTORY IMAGES FROM A CHEMICAL SENSOR USING A LIGHT-PULSE TECHNIQUE
SO NATURE
LA English
DT Article
ID system
AB THERE is much interest in the use of chemical sensor arrays, in conjunction with pattern-recognition routines, for developing artificial olfactory devices-'electronic noses'-which can characterize the chemical composition of gas mixtures 1-5. Here we describe a technique that uses a continuous sensing surface and a detection method involving a scanning pulsed light source, to generate images that represent a fingerprint of the gases detected. The detector is a large-area field-effect device with a number of different catalytic metals constituting the detecting surface (the device's active gate) 6,7.  A pulsed light beam scanned across this surface generates a photocapacitive current that varies with the value of the surface potential 8,9. A continuous sensing surface of this type provides information that would require an array of hundreds of discrete sensors. The technique also provides a new means of studying the coupling between the electronic properties of catalytic metals and chemical reactions taking place on their surfaces.
RP LUNDSTROM, I (corresponding author), LINKOPING UNIV,APPL PHYS LAB,S-58183 LINKOPING,SWEDEN.
NR 17
TC 135
Z9 146
U1 0
U2 33
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 47
EP 50
DI 10.1038/352047a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800064
DA 2026-03-10
ER

PT J
AU HYMAN, C
   HOFER, M
   BARDE, YA
   JUHASZ, M
   YANCOPOULOS, GD
   SQUINTO, SP
   LINDSAY, RM
AF HYMAN, C
   HOFER, M
   BARDE, YA
   JUHASZ, M
   YANCOPOULOS, GD
   SQUINTO, SP
   LINDSAY, RM
TI BDNF IS A NEUROTROPHIC FACTOR FOR DOPAMINERGIC-NEURONS OF THE SUBSTANTIA-NIGRA
SO NATURE
LA English
DT Article
ID invitro maturation; mesencephalic neurons; growth-factor; cells; survival; brain; cultures; density; mptp
AB Brain-derived neurotrophic factor (BDNF), present in minute amounts in the adult central nervous system 1, is a member of the nerve growth factor (NGF) (ref. 2) family, which includes neurotrophin-3 (NT-3) (refs 3-5). NGF, BDNF and NT-3 all support survival of subpopulations of neural crest-derived sensory neurons 3-5; most sympathetic neurons are responsive to NGF (ref. 2), but not to BDNF 1,6,7; NT-3 and BDNF, but not NGF (ref. 6), promote survival of sensory neurons of the nodose ganglion 3-8. BDNF, but not NGF, supports the survival of cultured retinal ganglion cells 9 but both NGF and BDNF promote the survival of septal cholinergic neurons in vitro 10,11. However, knowledge of their precise physiological role in development and maintenance of the nervous system neurons is still limited. The BDNF gene is expressed in many regions of the adult CNS 12-14, including the striatum 12. A protein partially purified from bovine striatum, a target of nigral dopaminergic neurons, with characteristics apparently similar to those of BDNF, can enhance the survival of dopaminergic neurons in mesencephalic cultures 15. BDNF seems to be a trophic factor for mesencephalic dopaminergic neurons, increasing their survival, including that of neuronal cells which degenerate in Parkinson's disease. Here we report the effects of BDNF on the survival of dopaminergic neurons of the developing substantia nigra.
C1 MAX PLANCK INST PSYCHIAT, DEPT NEUROCHEM, W-8033 PLANEGG, GERMANY.
C3 Max Planck Society
RP HYMAN, C (corresponding author), REGENERON PHARMACEUT INC, 777 OLD SAW MILL RIVER RD, TARRYTOWN, NY 10591 USA.
NR 34
TC 1404
Z9 1543
U1 0
U2 62
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 21
PY 1991
VL 350
IS 6315
BP 230
EP 232
DI 10.1038/350230a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FC779
UT WOS:A1991FC77900057
PM 2005978
DA 2026-03-10
ER

PT J
AU BROWN, RP
   THORPE, RS
   BAEZ, M
AF BROWN, RP
   THORPE, RS
   BAEZ, M
TI PARALLEL WITHIN-ISLAND MICROEVOLUTION OF LIZARDS ON NEIGHBORING ISLANDS
SO NATURE
LA English
DT Article
ID gallotia-galloti; evolutionary
AB THE correlation of changes in morphological traits with environmental gradients is often taken as evidence for natural selection 1. But in many cases, the possibility that this correlation is coincidental cannot be ruled out 2. Stronger evidence for natural selection is provided when closely related allopatric species show parallel patterns of geographic variation along similar environmental gradients. Vertebrate geographic variation within small islands provides a valuable opportunity to detect mechanisms of natural selection 3-5. We have now studied microgeographic variation in the colour patterns of two skinks (Lacertilia: Scincidae) from neighbouring heterogeneous islands. Parallel north-south variation occurs in the colour patterns of both species. Populations from the south of both islands possess conspicuous dorsal-tail coloration. Morphological distance matrices for both species are compared with similar aspects of environmental variation using simultaneous Mantel tests. This indicates that differential selection between lush and arid habitats is the primary cause of the variation in colour pattern.
C1 UNIV LA LAGUNA, FAC BIOL, DEPT ZOOL, San Cristobal la Laguna, SPAIN.
C3 Universidad de la Laguna
RP BROWN, RP (corresponding author), UNIV ABERDEEN, DEPT ZOOL, ABERDEEN AB9 2TN, SCOTLAND.
NR 17
TC 57
Z9 62
U1 1
U2 23
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 60
EP 62
DI 10.1038/352060a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800069
DA 2026-03-10
ER

PT J
AU SCHUMACHER, TNM
   DEBRUIJN, MLH
   VERNIE, LN
   KAST, WM
   MELIEF, CJM
   NEEFJES, JJ
   PLOEGH, HL
AF SCHUMACHER, TNM
   DEBRUIJN, MLH
   VERNIE, LN
   KAST, WM
   MELIEF, CJM
   NEEFJES, JJ
   PLOEGH, HL
TI PEPTIDE SELECTION BY MHC CLASS-I MOLECULES
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; h-2-deficient lymphoma variants; association; determinant; recognize; proteins; cells; hla
AB SYNTHETIC peptides have been used to sensitize target cells and thereby screen for epitopes recognized by T cells 1-7.  Most epitopes of cytotoxic T lymphocytes can be mimicked by synthetic peptides of 12-15 amino acids 8.  Although in specific cases, truncations of peptides improves sensitization of target cells 8,9, no optimum length for binding to major histocompatibility complex (MHC) class I molecules has been defined.  We have now analysed synthetic peptide captured by empty MHC class I molecules of the mutant cell line RMA-S.  We found that class I molecules preferentially bound short peptides (nine amino acids) and selectively bound these peptides even when they were a minor component in a mixture of longer peptides.  These results may help to explain the difference in size restriction of T-cell epitopes between experiments with synthetic peptides and those with naturally processed peptides 10-12.
C1 NETHERLANDS CANC INST,DEPT IMMUNOL,1066 CX AMSTERDAM,NETHERLANDS.
C3 Netherlands Cancer Institute
RP SCHUMACHER, TNM (corresponding author), NETHERLANDS CANC INST,DEPT CELLULAR BIOCHEM,PLESMANLAAN 121,1066 CX AMSTERDAM,NETHERLANDS.
NR 26
TC 278
Z9 321
U1 0
U2 6
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 25
PY 1991
VL 350
IS 6320
BP 703
EP 706
DI 10.1038/350703a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FJ130
UT WOS:A1991FJ13000059
PM 1708852
DA 2026-03-10
ER

PT J
AU CHOSSON, P
   LANAU, C
   CONNAN, J
   DESSORT, D
AF CHOSSON, P
   LANAU, C
   CONNAN, J
   DESSORT, D
TI BIODEGRADATION OF REFRACTORY HYDROCARBON BIOMARKERS FROM PETROLEUM UNDER LABORATORY CONDITIONS
SO NATURE
LA English
DT Article
ID crude oils; steranes; sediments; terpanes
AB BIOMARKERS are of great value in petroleum exploration because they provide essential information about the geological history of oils and source rocks.  Steranes 1 are of particular importance as they can be related to naturally occurring precursors 2, 3.  These compounds generally experience intense biodegradation, however, which alters their original distribution 4-6 and obscures the information that they carry regarding oil maturity and source material.  In an attempt to identify the microorganisms responsible for this degradation, we have investigated the capacity of 73 aerobic bacteria to degrade steranes present in Rozel Point (Utah) oil 7.  Seven Gram-positive strains, belonging to a limited number of genera, were found to be active.  Using Nocardia sp. SEBR 16, which caused the most extensive alteration, we have determined biodegradation rates for several isomers of steranes and methylsteranes.  The preference for alteration of different isomers reflects that observed in natural environments, suggesting that the degradation intermediates could be used as indicators of the extent of the biodegradation in an oil.  In addition, the microorganisms used here might be effective in biodegrading oil spills.
C1 ELF AQUITAINE,CSTJF,F-64018 PAU,FRANCE.
C3 Total SA; Centre Scientifique et Technique Jean Feger (CSTJF)
RP CHOSSON, P (corresponding author), SANOFI ELF BIORECH,BP 137,F-31328 LABEGE,FRANCE.
NR 15
TC 63
Z9 73
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 640
EP 642
DI 10.1038/351640a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200061
PM 2052089
DA 2026-03-10
ER

PT J
AU CRUICKSHANK, ARI
   SMALL, PG
   TAYLOR, MA
AF CRUICKSHANK, ARI
   SMALL, PG
   TAYLOR, MA
TI DORSAL NOSTRILS AND HYDRODYNAMICALLY DRIVEN UNDERWATER OLFACTION IN PLESIOSAURS
SO NATURE
LA English
DT Article
AB THE dorsally placed external nostrils of plesiosaurs are usually regarded as an adaptation to breathing in those extinct marine reptiles. We suggest instead that the narial system was used in underwater olfaction. The internal nares are anterior to the external nares. Hydrodynamic pressure during swimming forced water into the mouth, along palatal grooves into the scoop-shaped internal nares and up short ducts, presumably lined with olfactory epithelia. Alternatively, or additionally, the so far unlocated Jacobson's organ detected particulate matter. The water was sucked out through the external nares by hydrodynamic pressures generated by fast flow over the convex upper surface of the head.
C1 UNIV NOTTINGHAM,QUEENS MED CTR,SCH MED,DEPT XRAY,NOTTINGHAM NG7 2UH,ENGLAND.
C3 University of Nottingham
RP CRUICKSHANK, ARI (corresponding author), LEICESTERSHIRE MUSEUMS,ARTS & RECORDS SERV,96 NEW WALK,LEICESTER LE1 6TD,ENGLAND.
NR 13
TC 29
Z9 32
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 62
EP 64
DI 10.1038/352062a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800070
DA 2026-03-10
ER

PT J
AU STEDMAN, HH
   SWEENEY, HL
   SHRAGER, JB
   MAGUIRE, HC
   PANETTIERI, RA
   PETROF, B
   NARUSAWA, M
   LEFEROVICH, JM
   SLADKY, JT
   KELLY, AM
AF STEDMAN, HH
   SWEENEY, HL
   SHRAGER, JB
   MAGUIRE, HC
   PANETTIERI, RA
   PETROF, B
   NARUSAWA, M
   LEFEROVICH, JM
   SLADKY, JT
   KELLY, AM
TI THE MDX MOUSE DIAPHRAGM REPRODUCES THE DEGENERATIVE CHANGES OF DUCHENNE MUSCULAR-DYSTROPHY
SO NATURE
LA English
DT Article
ID skeletal-muscle myopathy; satellite cells; rat; product; growth; invivo; gene
AB ALTHOUGH murine X-linked muscular dystrophy (mdx) and Duchenne muscular dystrophy (DMD) are genetically homologous and both characterized by a complete absence of dystrophin 1,2, the limb muscles of adult mdx mice suffer neither the detectable weakness nor the progressive degeneration that are features of DMD 3-8.  Here we show that the mdx mouse diaphragm exhibits a pattern of degeneration, fibrosis and severe functional deficit comparable to that of DMD limb muscle, although adult mice show no overt respiratory impairment. Progressive functional changes include reductions in strength (to 13.5% of control by two years of age), elasticity, twitch speed and fibre length. The collagen density rises to at least seven times that of control diaphragm and ten times that of mdx hind-limb muscle. By 1.5 years of age, similar but less severe histological changes emerge in the accessory muscles of respiration. On the basis of these findings, we propose that dystrophin deficiency alters the threshold for work-induced injury. Our data provide a quantitative framework for studying the pathogenesis of dystrophy and extend the application of the mdx mouse as an animal model.
C1 UNIV PENN,SCH VET MED,PHILADELPHIA,PA 19104.
C3 University of Pennsylvania
RP STEDMAN, HH (corresponding author), UNIV PENN,SCH MED,3800 SPRUCE ST,PHILADELPHIA,PA 19104, USA.
NR 25
TC 804
Z9 930
U1 0
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 536
EP 539
DI 10.1038/352536a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600065
PM 1865908
DA 2026-03-10
ER

PT J
AU JARDETZKY, TS
   LANE, WS
   ROBINSON, RA
   MADDEN, DR
   WILEY, DC
AF JARDETZKY, TS
   LANE, WS
   ROBINSON, RA
   MADDEN, DR
   WILEY, DC
TI IDENTIFICATION OF SELF PEPTIDES BOUND TO PURIFIED HLA-B27
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; class-i molecules; major histocompatibility complex; amino-acid sequences; heat-shock protein; developmental biology; antigen presentation; viral peptides; hla antigens; mhc
AB A pool of endogenous peptides bound to the human class I MHC molecule, HLA-B27, has been isolated.  Microsequence analysis of the pool and of 11 HPLC-purified peptides provides information on the binding specificity of the HLA-B27 molecule.  The peptides all seem to be nonamers, seven of which match to protein sequences in a database search.  These self peptides derive from abundant cytosolic or nuclear proteins, such as histone, ribosomal proteins, and members of the 90K heat-shock protein family.
C1 HARVARD UNIV,HOWARD HUGHES MED INST,CAMBRIDGE,MA 02138.
   HARVARD UNIV,COMM HIGHER DEGREES BIOPHYS,CAMBRIDGE,MA 02138.
   HARVARD MICROCHEM FACIL,CAMBRIDGE,MA 02138.
C3 Howard Hughes Medical Institute; Harvard University; Harvard University; Harvard University
RP JARDETZKY, TS (corresponding author), HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,7 DIVIN AVE,CAMBRIDGE,MA 02138, USA.
NR 46
TC 865
Z9 921
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 326
EP 329
DI 10.1038/353326a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400049
PM 1922338
DA 2026-03-10
ER

PT J
AU LATIN, D
   WATERS, FG
AF LATIN, D
   WATERS, FG
TI MELT GENERATION DURING RIFTING IN THE NORTH-SEA
SO NATURE
LA English
DT Article
ID mantle; lithosphere; subsidence; extension; chemistry; basin
AB IN a forthcoming paper, McKenzie and O'Nions 1 invert rare-earth element concentrations in mid-ocean-ridge basalts to calculate the variation of melt fraction with depth in the asthenospheric mantle beneath ocean ridges.  They find that melting persists to greater depths (about 80 km) than would be predicted by parameterizations of melting experiments 2 (about 50 km).  This result has important implications for predicting the volume and composition of melt produced from asthenosphere of normal potential temperature during continental rifting.  The North Sea rift is a good location to test models for melt generation because the physical conditions of rifting are well constrained 3-8.  Using the distribution of melt fraction with depth derived in ref. 1, we calculate the volume and composition of melt produced from the asthenosphere in the most stretched part of the North Sea (the Forties region).  When this melt is mixed in approximately equal proportions with an alkaline melt, similar to that produced from metasomatized lithosphere by very small amounts of stretching on the rift flanks, it accounts for the volume and the elemental and isotopic composition of the basalts in the most extended region.
C1 UNIV CAMBRIDGE,DEPT EARTH SCI,CAMBRIDGE CB2 3EQ,ENGLAND.
C3 University of Cambridge
RP LATIN, D (corresponding author), UNIV CAMBRIDGE,BULLARD LABS,MADINGLEY RD,CAMBRIDGE CB3 0EZ,ENGLAND.
NR 25
TC 38
Z9 39
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 559
EP 562
DI 10.1038/351559a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400056
DA 2026-03-10
ER

PT J
AU COATES, MI
   CLACK, JA
AF COATES, MI
   CLACK, JA
TI FISH-LIKE GILLS AND BREATHING IN THE EARLIEST KNOWN TETRAPOD
SO NATURE
LA English
DT Article
AB THE origin of tetrapods is generally associated with the emergence of terrestrial vertebrate life. Anatomical features unique to tetrapods are usually considered to be adaptations to the terrestrial environment. Here we report the discovery of a fish-like branchial skeleton in Acanthostega gunnari, from the Upper Devonian of East Greenland, one of the earliest tetrapods known. It shows a proximally expanded ceratohyal and large, ventrally grooved ceratobranchials. Such grooves are found in the ceratobranchials of modern fishes, and house the afferent branchial aortic arches. The shoulder girdle bears a postbranchial lamina along its anterior margin. In fishes this supports the posterior wall of the opercular chamber. Acanthostega seems to have retained fish-like internal gills and an open opercular chamber for use in aquatic respiration, implying that the earliest tetrapods were not fully terrestrial. The discovery provides information on the sequence of acquisition of tetrapod characters, and supports previous suggestions that such characters as legs with digits' evolved first for use in water.
RP COATES, MI (corresponding author), UNIV CAMBRIDGE,MUSEUM ZOOL,DOWNING ST,CAMBRIDGE CB4 3EJ,ENGLAND.
NR 15
TC 137
Z9 145
U1 0
U2 46
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 234
EP 236
DI 10.1038/352234a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500063
DA 2026-03-10
ER

PT J
AU WIKLER, KC
   RAKIC, P
AF WIKLER, KC
   RAKIC, P
TI RELATION OF AN ARRAY OF EARLY-DIFFERENTIATING CONES TO THE PHOTORECEPTOR MOSAIC IN THE PRIMATE RETINA
SO NATURE
LA English
DT Article
ID rhesus-monkey retina; lineage; green; blue
AB THE retina of diurnal primates, including humans, contains a reiterative mosaic of red-, green- and blue-sensitive cones whose visual pigments are maximally sensitive to long, middle or short wavelengths, respectively 1.  Although the distribution of the cone subtypes in the adult rhesus monkey has been quantified using opsin-specific antisera 2, the mechanism for the phenotypic specification of the cone subtypes and the establishment of their ratios in the retinal mosaic remain unknown.  Here we present immunocytochemical evidence that a subset of cones (about 10%) express their cell-specific opsin two to three weeks before the surrounding cones.  Remarkably, these precocious cones are evenly stationed throughout undifferentiated regions of the retinal surface from several weeks after their last mitotic division 3, and at least one month before the formation of their synapses with bipolar and horizontal cells 4.  Use of confocal laser microscopy reveals that the inner segments of immunolabelled and surrounding unlabelled cones are transiently in apposition with one another, enabling surface mediated interactions to occur during this period.  We suggest that the early maturing cones induce neighbouring undifferentiated cones to express an appropriate opsin phenotype, and therefore constitute a 'protomap' for the emergence of the species-specific retinal mosaic.
RP WIKLER, KC (corresponding author), YALE UNIV,SCH MED,NEUROBIOL SECT,POB 3333,NEW HAVEN,CT 06510, USA.
NR 20
TC 78
Z9 83
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 397
EP 400
DI 10.1038/351397a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600055
PM 1827876
DA 2026-03-10
ER

PT J
AU COTTON, RGH
   MALCOLM, ADB
AF COTTON, RGH
   MALCOLM, ADB
TI MUTATION DETECTION
SO NATURE
LA English
DT Article
ID sickle-cell-anemia; polymerase chain-reaction; dna; hybridization; amplification; diagnosis; cytosine; thymine; allele; gene
C1 CHARING CROSS & WESTMINSTER MED SCH, DEPT BIOCHEM, LONDON W6 8RF, ENGLAND.
C3 Imperial College London
RP COTTON, RGH (corresponding author), ROYAL CHILDRENS HOSP, MURDOCH INST RES BIRTH DEFECTS, FLEMINGTON RD, PARKVILLE, VIC 3052, AUSTRALIA.
NR 16
TC 12
Z9 14
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 582
EP 583
DI 10.1038/353582a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300076
PM 1922369
DA 2026-03-10
ER

PT J
AU HONDA, M
   MCDOUGALL, I
   PATTERSON, DB
   DOULGERIS, A
   CLAGUE, DA
AF HONDA, M
   MCDOUGALL, I
   PATTERSON, DB
   DOULGERIS, A
   CLAGUE, DA
TI POSSIBLE SOLAR NOBLE-GAS COMPONENT IN HAWAIIAN BASALTS
SO NATURE
LA English
DT Article
ID loihi seamount; neon; isotopes; helium; xenoliths; diamonds; island
AB The noble-gas elemental and isotopic composition in the Earth is significantly different from that of the present atmosphere, and provides an important clue to the origin and history of the Earth and its atmosphere. Possible candidates for the noble-gas composition of the primordial Earth include a solar-like component, a planetary-like component (as observed in primitive meteorites) and a component similar in composition to the present atmosphere. In an attempt to identify the contributions of such components, we have measured isotope ratios of heliium and neon in fresh basaltic glasses dredged from Loihi seamount and the East Rift Zone of Kilauea 1-3. We find a systematic enrichment in Ne-20, and Ne-21 relative to Ne-22, compared with atmospheric neon. The helium and neon isotope signatures observed in our samples can be explained by mixing of solar, present atmospheric, radiogenic and nucleogenic components. These data suggest that the noble-gas isotopic composition of the mantle source of the Hawaiian plume is different from that of the present atmosphere, and that it includes a significant solar-like component. We infer that this component was acquired during the formation of the Earth.
C1 US GEOL SURVEY, MENLO PK, CA 94025 USA.
C3 United States Department of the Interior; United States Geological Survey
RP HONDA, M (corresponding author), AUSTRALIAN NATL UNIV, RES SCH EARTH SCI, GPO BOX 4, CANBERRA, ACT 2601, AUSTRALIA.
NR 17
TC 283
Z9 297
U1 0
U2 14
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 149
EP 151
DI 10.1038/349149a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800055
DA 2026-03-10
ER

PT J
AU FUGATE, RQ
   FRIED, DL
   AMEER, GA
   BOEKE, BR
   BROWNE, SL
   ROBERTS, PH
   RUANE, RE
   TYLER, GA
   WOPAT, LM
AF FUGATE, RQ
   FRIED, DL
   AMEER, GA
   BOEKE, BR
   BROWNE, SL
   ROBERTS, PH
   RUANE, RE
   TYLER, GA
   WOPAT, LM
TI MEASUREMENT OF ATMOSPHERIC WAVE-FRONT DISTORTION USING SCATTERED-LIGHT FROM A LASER GUIDE-STAR
SO NATURE
LA English
DT Article
AB THE possibility of using an artificial 'guide-star' to measure optical wavefront distortion caused by atmospheric turbulence has been discussed for some time 1-4, but few experimental data are available 5.  Here we report experimental results demonstrating that atmospheric wavefront distortion can be measured by taking fast 'snapshots' of a guide-star formed by light scattered from a laser beam focused in the upper atmosphere. These results agree with a theoretical prediction 6 that the mean-square wavefront error created by using an artificial guide-star at a finite distance rather than a real (infinitely distant) star is proportional to the five-thirds power of the telescope aperture. Using this understanding of the physics, we have demonstrated continuous, real-time atmospheric compensation of a 1.5-m telescope using a high-pulse-rate laser, pulse-synchronized wavefront sensor and deformable mirror, and have been able to resolve the 1.3-arcsecond binary star 53 xi-Ursa Majoris in an exposure time of only one second.
C1 OPT SCI CO,PLACENTIA,CA 92670.
RP FUGATE, RQ (corresponding author), PHILLIPS LAB LTE,STARFIRE OPT RANGE,KIRTLAND AFB,NM 87117, USA.
NR 16
TC 193
Z9 219
U1 0
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 144
EP 146
DI 10.1038/353144a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100046
DA 2026-03-10
ER

PT J
AU TEH, HS
   GARVIN, AM
   FORBUSH, KA
   CARLOW, DA
   DAVIS, CB
   LITTMAN, DR
   PERLMUTTER, RM
AF TEH, HS
   GARVIN, AM
   FORBUSH, KA
   CARLOW, DA
   DAVIS, CB
   LITTMAN, DR
   PERLMUTTER, RM
TI PARTICIPATION OF CD4 CORECEPTOR MOLECULES IN T-CELL REPERTOIRE SELECTION
SO NATURE
LA English
DT Article
ID antigen receptor; transgenic mice; recognition; expression; lines; mouse; gene
AB DURING thymocyte development, progenitor cells bearing both CD4 and CD8 coreceptor molecules mature into functional T lymphocytes that express these proteins in a mutually exclusive way 1. Although T-cell specificity is determined primarily by the structure of the T-cell antigen receptor (TCR) heterodimer 2, a developmentally regulated process acts to ensure that cells bearing class II-restricted TCRs are CD4+ and those bearing class I-restricted TCRs express, only CD8 (ref.3). To investigate this maturation process, we have engineered transgenic mice in which CD4 is expressed in all thymocyte subsets and in all peripheral T cells. Peripheral CD4+8+ T lymphocytes from these mice react with both class I and class II alloantigens. Moreover, expression of the CD4 transgene disrupts the positive selection of doubly transgenic thymocytes bearing a class I-restricted TCR specific for the male (H-Y) antigen. Hence the CD4 coreceptor participates directly in T-cell repertoire selection.
C1 UNIV WASHINGTON, DEPT BIOCHEM, SEATTLE, WA 98195 USA.
   UNIV WASHINGTON, DEPT IMMUNOL, SEATTLE, WA 98195 USA.
   UNIV WASHINGTON, DEPT MED MED GENET, SEATTLE, WA 98195 USA.
   UNIV WASHINGTON, HOWARD HUGHES MED INST, SEATTLE, WA 98195 USA.
   UNIV CALIF SAN FRANCISCO, HOWARD HUGHES MED INST, SAN FRANCISCO, CA 94143 USA.
   UNIV CALIF SAN FRANCISCO, DEPT MICROBIOL & IMMUNOL, SAN FRANCISCO, CA 94143 USA.
   UNIV BRITISH COLUMBIA, DEPT MICROBIOL, VANCOUVER V6T 1W5, BC, CANADA.
C3 University of Washington; University of Washington Seattle; University of Washington; University of Washington Seattle; University of Washington; University of Washington Seattle; University of Washington; University of Washington Seattle; Howard Hughes Medical Institute; Howard Hughes Medical Institute; University of California System; University of California San Francisco; University of California System; University of California San Francisco; University of British Columbia
NR 27
TC 87
Z9 89
U1 0
U2 0
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 17
PY 1991
VL 349
IS 6306
BP 241
EP 243
DI 10.1038/349241a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ET519
UT WOS:A1991ET51900056
PM 1824796
DA 2026-03-10
ER

PT J
AU DICKSON, JAD
AF DICKSON, JAD
TI DISEQUILIBRIUM CARBON AND OXYGEN ISOTOPE VARIATIONS IN NATURAL CALCITE
SO NATURE
LA English
DT Article
ID fractionation
AB OXYGEN isotope fractionation in the calcite-water system is widely used to investigate the temperature, fluid composition and reaction rate of calcite precipitation, under the assumption that equilibrium is maintained during precipitation. Here I present analyses of coarsely crystalline, inorganic calcite displaying combined growth and sector zoning, which show this assumption to be untrue. Variations in the isotope composition of successive growth zones can be interpreted as due to changing conditions of precipitation, with equilibrium being maintained throughout. But variations across different sectors of the same synchronous growth surface (approximately 2 parts per thousand for delta-C-13 and approximately 0.9 parts per thousand for delta-O-18) record disequilibrium in the same crystal. This type of disequilibrium may be common, as calcite precipitates in a great variety of crystal form combinations; moreover, many noncarbonate minerals also grow as crystals with two or more crystallographic forms. Indeed, Boyd et al. 1 reported fractionation of nitrogen isotopes between cubic and octahedral sectors of a synthetic diamond, but I believe that crystallographically controlled isotope fractionation of stoichiometric ions has not hitherto been recognized.
RP DICKSON, JAD (corresponding author), UNIV CAMBRIDGE,DEPT EARTH SCI,DOWNING ST,CAMBRIDGE CB2 3EQ,ENGLAND.
NR 15
TC 48
Z9 52
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 842
EP 844
DI 10.1038/353842a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200058
DA 2026-03-10
ER

PT J
AU CUBELLI, R
AF CUBELLI, R
TI A SELECTIVE DEFICIT FOR WRITING VOWELS IN ACQUIRED DYSGRAPHIA
SO NATURE
LA English
DT Article
ID graphemic buffer
AB BRAIN-DAMAGED patients with acquired writing disorders provide important information about the normal processes of spelling and writing 1,2.  Current models indicate that to produce a letter string, its 'abstract' representation is computed and stored in a temporary orthographic buffer, from which it is converted to a verbal code (if the word is to be spelled aloud) or to a physical letter code (if the word is to be written). The stored graphemic representations specify the identity and order of the component letters 3 and their consonant/vowel status 4.  Here I describe the spelling performance of two patients with a selective deficit in writing vowels. When writing words, the first patient omitted all vowels, leaving a blank space between consonants or consonant clusters, whereas the second produced errors that almost exclusively involved vowels. This pattern of performance supports the hypothesis that the consonant/vowel status of graphemes is differentially specified in the spelling process and may be selectively affected after brain damage.
RP CUBELLI, R (corresponding author), OSPED MAGGIORE BOLOGNA,DEPT REHABIL,I-40133 BOLOGNA,ITALY.
NR 9
TC 72
Z9 73
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 258
EP 260
DI 10.1038/353258a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400059
PM 1896072
DA 2026-03-10
ER

PT J
AU SNOW, AA
   SPIRA, TP
AF SNOW, AA
   SPIRA, TP
TI POLLEN VIGOR AND THE POTENTIAL FOR SEXUAL SELECTION IN PLANTS
SO NATURE
LA English
DT Article
ID multiple paternity; raphanus-sativus; wild radish; tube growth; consequences; pollinations; carryover; success
AB DISCOVERING whether paternal fecundity varies within populations is crucial for evaluating whether male-male competition and/or female choice can lead to sexual selection 1-3. In natural populations of plants, pollinators often deposit mixtures of 'surplus' pollen from several individuals onto receptive stigmas 4-7. Therefore within-flower competition among pollen-tubes for ovules could lead to nonrandom paternal success. We found that pollen competition was common in populations of wild rose mallow (Hibiscus moscheutos). Co-occurring individuals often differed in mean pollen-tube growth rates, and this trait was correlated with the number of seeds the plants sired when pollen mixtures were applied to stigmas. Differences between pairs of individuals in pollen-tube growth rates were consistent across maternal plants, suggesting that sexual selection can occur. This unexpected variation in pollen vigour could lead to nonrandom fertilization whenever pollen-tubes compete for access to ovules.
C1 GEORGIA SO UNIV, DEPT BIOL, STATESBORO, GA 30460 USA.
   SMITHSONIAN ENVIRONM RES CTR, EDGEWATER, MD 21037 USA.
C3 University System of Georgia; Georgia Southern University; Smithsonian Institution; Smithsonian Environmental Research Center
RP SNOW, AA (corresponding author), OHIO STATE UNIV, DEPT PLANT BIOL, COLUMBUS, OH 43210 USA.
NR 28
TC 177
Z9 189
U1 1
U2 52
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 796
EP 797
DI 10.1038/352796a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400057
DA 2026-03-10
ER

PT J
AU SHANNON, MD
   CASCI, JL
   COX, PA
   ANDREWS, SJ
AF SHANNON, MD
   CASCI, JL
   COX, PA
   ANDREWS, SJ
TI STRUCTURE OF THE 2-DIMENSIONAL MEDIUM-PORE HIGH-SILICA ZEOLITE NU-87
SO NATURE
LA English
DT Article
ID crystal-structure
AB SYNTHETIC alumino-silicate zeolites are widely used in the petrochemical industry as catalysts.  In particular the few with multidimensional channel systems are highly valued, as they permit more complex chemistry within the pores and are less prone to deactivation through coking than are one-dimensional systems.  Materials with a high silica content have improved stability towards heat in the presence or absence of steam (conditions frequently encountered in catalytic processes).  NU-87 is a recently synthesized, medium-pore high-silica zeolite 1 with promising catalytic properties 2.  Here we describe its framework topology as deduced by electron diffraction.  The data were refined by comparison with X-ray powder diffraction patterns using geometric criteria, lattice-energy minimization and Rietveld refinement.  The structure is unique in having a two-dimensional channel system defined by rings of 10 oxygen atoms within the framework (10-ring windows).  Adjacent one-dimensional 10-ring channels are linked by short 12-ring channels to create a two-dimensional network, but access to these bridging sections is possible only via the 10-ring windows.  Although the past two decades have seen considerable advances in the synthesis of novel zeolite frameworks 3, NU-87 is the first high-silica 10-ring zeolite with intersecting channels to be synthesized since the industrially important ZSM-5 4 and ZSM-11 5 (both of which have three-dimensional channel systems) nearly 20 years ago.
C1 ICI CHEM & POLYMERS LTD,WILTON TS6 8JE,ENGLAND.
   ICI PLC,WILTON MAT RES CTR,WILTON TS6 8JE,ENGLAND.
RP SHANNON, MD (corresponding author), ICI CHEM & POLYMERS LTD,POB 8,RUNCORN WA7 4QD,ENGLAND.
NR 20
TC 109
Z9 117
U1 0
U2 59
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 417
EP 420
DI 10.1038/353417a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600052
DA 2026-03-10
ER

PT J
AU MOORE, JM
   PEATTIE, DA
   FITZGIBBON, MJ
   THOMSON, JA
AF MOORE, JM
   PEATTIE, DA
   FITZGIBBON, MJ
   THOMSON, JA
TI SOLUTION STRUCTURE OF THE MAJOR BINDING-PROTEIN FOR THE IMMUNOSUPPRESSANT FK506
SO NATURE
LA English
DT Article
ID cis-trans isomerase; peptidyl-prolyl isomerase; fk506-binding protein; h-1-nmr spectra; cyclosporin-a; cyclophilin; distinct; pathways; cell
AB THE major FK506 binding protein (FKBP, relative molecular mass approximately 11,800; M(r) 11.8K) and cyclophilin (M(r) approximately 17K) belong to a class of proteins termed immunophilins 1.  Although unrelated at the amino-acid sequence level, they both possess peptidyl-prolyl cis-trans isomerase activities which are inhibited by immunosuppressants that block signal transduction pathways leading to T-lymphocyte activation.  FK506 and rapamycin strongly inhibit the peptidyl-prolyl cis-trans isomerase activity of FKBP, whereas cyclosporin A inhibits that of cyclophilin 2-12.  The significance of this enzyme activity and the role of the immunophilins in immunoregulation is unknown 1,13.  To understand better the function of the immunophilins and their interaction with inhibitors, we are investigating the solution structures of FKBP and FKBP-inhibitor complexes by multidimensional NMR methods.  Here we report the solution conformation of FKBP, as generated by NMR, distance geometry and molecular dynamics methods.  The regular secondary structure of FKBP is composed mainly of beta-sheet (approximately 35%) with little helical structure (< 10%).  The hydrophobic core of the molecule, containing the buried side chains of six of the protein's nine aromatic amino acids, is enclosed by a five-stranded antiparallel beta-sheet on one side, a loop and a short helix at residues 51-56 and 57-65, and an aperiodic loop at residues 81-95.  Examination of the structure suggests a possible site of interaction with FK506.
RP MOORE, JM (corresponding author), VERTEX PHARMACEUT INC,40 ALLSTON ST,CAMBRIDGE,MA 02139, USA.
NR 27
TC 151
Z9 160
U1 0
U2 15
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 248
EP 250
DI 10.1038/351248a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000062
PM 2041572
DA 2026-03-10
ER

PT J
AU MULKEY, RM
   ZUCKER, RS
AF MULKEY, RM
   ZUCKER, RS
TI ACTION-POTENTIALS MUST ADMIT CALCIUM TO EVOKE TRANSMITTER RELEASE
SO NATURE
LA English
DT Article
ID neurotransmitter release; nerve terminals; facilitation; depolarization; crayfish; entry; influx
AB THERE are two hypotheses to explain how neurons release transmitter.  The calcium hypothesis proposes that membrane depolarization is necessary only for opening calcium channels and increasing internal calcium concentration ([Ca2+]i) near membrane transmitter-release sites 1-3.  These calcium ions trigger a transient release of neurotransmitter 4,5.  The calcium-voltage hypothesis postulates that voltage induces a conformational change in a membrane protein rendering it sensitive to calcium such that, in the presence of high [Ca2+]i, depolarization directly triggers transmitter release 6-9.  Here we report that when calcium influx is blocked by cobalt or manganese ions in a calcium-free Ringer, as measured with Fura-2, and [Ca2+]i is elevated by liberation from a caged calcium compound, transmitter release at the crayfish neuromuscular junction is unaffected by presynaptic action potentials.  These results support the calcium hypothesis.
RP MULKEY, RM (corresponding author), UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,DIV NEUROBIOL,BERKELEY,CA 94720, USA.
NR 20
TC 107
Z9 111
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 153
EP 155
DI 10.1038/350153a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500058
PM 1672444
DA 2026-03-10
ER

PT J
AU KOOPMAN, P
   GUBBAY, J
   VIVIAN, N
   GOODFELLOW, P
   LOVELLBADGE, R
AF KOOPMAN, P
   GUBBAY, J
   VIVIAN, N
   GOODFELLOW, P
   LOVELLBADGE, R
TI MALE DEVELOPMENT OF CHROMOSOMALLY FEMALE MICE TRANSGENIC FOR SRY
SO NATURE
LA English
DT Article
ID testis-determining gene; sex-reversed mice; y-chromosome; mouse; duplication; expression
AB The initiation of male development in mammals requires one or more genes on the Y chromosome.  A recently isolated gene, termed SRY in humans and Sry in mouse, has many of the genetic and biological properties expected of a Y-located testis-determining gene.  It is now shown that Sry on a 14-kilobase genomic DNA fragment is sufficient to induce testis differentiation and subsequent male development when introduced into chromosomally female mouse embryos.
C1 NATL INST MED RES,MRC,EUKARYOT MOLEC GENET LAB,LONDON NW7 1AA,ENGLAND.
   IMPERIAL CANC RES FUND,HUMAN MOLEC GENET LAB,LONDON WC2A 3PX,ENGLAND.
C3 MRC National Institute for Medical Research; Cancer Research UK
FU Medical Research Council [MC_U117562207] Funding Source: Medline
NR 42
TC 1802
Z9 2079
U1 1
U2 156
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 117
EP 121
DI 10.1038/351117a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500040
PM 2030730
DA 2026-03-10
ER

PT J
AU MULLER, W
   CONNOR, JA
AF MULLER, W
   CONNOR, JA
TI DENDRITIC SPINES AS INDIVIDUAL NEURONAL COMPARTMENTS FOR SYNAPTIC CA2+ RESPONSES
SO NATURE
LA English
DT Article
ID long-term potentiation; hippocampal pyramidal cells; excitatory amino-acids; synapses; block
AB THE possibility that postsynaptic spines on neuronal dendrites are discrete biochemical compartments for Ca2+-activated processes involved in synaptic plasticity 1-6 is a widely proposed concept that has eluded experimental demonstration. Using microfluorometry on CA3 neurons in hippocampal slices, we show here that with weak presynaptic stimulation of associative/commissural fibres, Ca2+ accumulates in single postsynaptic spines but not in the parent dendrite. Stronger stimulation also promotes changes in dendrites. The NMDA-receptor antagonist AP-5 blocks changes in Ca2+ in spines. Sustained steep Ca2+ gradients between single spines and the parent dendrite, often lasting several minutes, develop with repeated stimulation. The observed compartmentalization allows for the specificity 7,8, cooperativity 9 and associativity 10-14 displayed by memory models such as long-term potentiation.
RP MULLER, W (corresponding author), ROCHE INST MOLEC BIOL,ROCHE RES CTR,DEPT NEUROSCI,340 KINGSLAND ST,NUTLEY,NJ 07110, USA.
NR 23
TC 419
Z9 458
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 73
EP 76
DI 10.1038/354073a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900061
PM 1682815
DA 2026-03-10
ER

PT J
AU NEUGEBAUER, KM
   REICHARDT, LF
AF NEUGEBAUER, KM
   REICHARDT, LF
TI CELL-SURFACE REGULATION OF BETA-1-INTEGRIN ACTIVITY ON DEVELOPING RETINAL NEURONS
SO NATURE
LA English
DT Article
ID glycoprotein; proteins; complex; laminin; csat
AB INTEGRINS are a family of alpha-beta-heterodimeric receptors that mediate cell-cell and cell-substratum interactions. Integrin binding to extracellular ligands regulates cell adhesion, shape, motility, intracellular signalling and gene expression 1-3. Mechanisms that regulate integrin function are, therefore, central to the participation of integrins in a diverse set of cellular events. Here we report the identification of TASC, a monoclonal antibody to a novel epitope on the integrin beta-1 subunit, which inhibits cell adhesion to vitronectin but promotes adhesion to laminin and collagen types I and IV. We show that developing retinal neurons that have lost responsiveness to laminin 4 regain the ability to bind laminin in the presence of TASC. Thus, beta-1-class integrins are likely to occupy multiple affinity states that can be modulated at the cell surface.
C1 UNIV CALIF SAN FRANCISCO, HOWARD HUGHES MED INST, SAN FRANCISCO, CA 94143 USA.
   UNIV CALIF SAN FRANCISCO, DEPT PHYSIOL, SAN FRANCISCO, CA 94143 USA.
C3 Howard Hughes Medical Institute; University of California System; University of California San Francisco; University of California System; University of California San Francisco
FU NINDS NIH HHS [R01 NS019090] Funding Source: Medline
NR 25
TC 183
Z9 189
U1 1
U2 4
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 68
EP 71
DI 10.1038/350068a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300067
PM 1706071
DA 2026-03-10
ER

PT J
AU KELLY, AP
   MONACO, JJ
   CHO, SG
   TROWSDALE, J
AF KELLY, AP
   MONACO, JJ
   CHO, SG
   TROWSDALE, J
TI A NEW HUMAN HLA CLASS-II-RELATED LOCUS, DM
SO NATURE
LA English
DT Article
ID dq-subregion; chain gene; mhc; molecules; sequence; distinct; region; beta
AB HLA CLASS II molecules have a crucial role in the immune response to antigens.   We have isolated two new class II-like complementary DNA sequences, RING6 and RING7, which map between the HLA-DNA and -DOB loci.  They are novel members of the immunoglobulin gene family which may have diverged before the duplications that gave rise to the main class II loci.  The RING6 and RING7 genes seem to encode alpha- and beta-chains of a previously undiscovered class II-related protein.
C1 VIRGINIA COMMONWEALTH UNIV,MED COLL VIRGINIA,DEPT MICROBIOL & IMMUNOL,RICHMOND,VA 23298.
C3 Virginia Commonwealth University
RP KELLY, AP (corresponding author), IMPERIAL CANC RES FUND,HUMAN IMMUNOGENET LAB,LINCOLNS INN FIELDS,LONDON WC2A 3PX,ENGLAND.
NR 18
TC 256
Z9 283
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 571
EP 573
DI 10.1038/353571a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300072
PM 1922365
DA 2026-03-10
ER

PT J
AU GLYNNE, R
   POWIS, SH
   BECK, S
   KELLY, A
   KERR, LA
   TROWSDALE, J
AF GLYNNE, R
   POWIS, SH
   BECK, S
   KELLY, A
   KERR, LA
   TROWSDALE, J
TI A PROTEASOME-RELATED GENE BETWEEN THE 2 ABC TRANSPORTER LOCI IN THE CLASS-II REGION OF THE HUMAN MHC
SO NATURE
LA English
DT Article
ID major histocompatibility complex; molecular-weight proteinase; influenza nucleoprotein; antigen presentation; t-cells; purification; sequences; macropain; pathway; liver
AB IT is now possible to paint a detailed picture of how cytoplasmic proteins are handled by the immune system 1-7.  They are apparently degraded in the cytoplasm into peptides.  These are then transported into the endoplasmic reticulum where they encounter class I major histocompatibility complex (MHC) molecules.  Once loaded with peptide, the HLA molecules move through the Golgi apparatus to the cell membrane.  Until recently, it had not been established how peptides without signal sequences cross the ER membrane.  However, a number of papers have now described a pair of membrane transporter genes of the ABC (ATP-binding cassette) super-family which are attractive candidates for this function 8-12.  Both transporter genes, which may encode two halves of a heterodimer, are situated in the class II region of the MHC.  There is evidence that other putative components of the processing machinery, the LMPs (low molecular mass polypeptides), are also encoded in the MHC 13-15.  Similarities between the properties of the LMPs and a large intracellular protease complex, called proteasome, have led to the suggestion that LMPs are involved in processing antigens 16.  We have now identified a human gene with sequence homology to proteasome components.  Remarkably, this gene maps between the two putative peptide transporter genes.
C1 UNITED MED & DENT SCH GUYS & ST THOMAS HOSP,LONDON SE1 9RT,ENGLAND.
C3 University of London; King's College London
RP GLYNNE, R (corresponding author), IMPERIAL CANC RES FUND,HUMAN IMMUNOGENET LAB,LINCOLNS INN FIELDS,LONDON WC2A 3PX,ENGLAND.
NR 32
TC 421
Z9 442
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 357
EP 360
DI 10.1038/353357a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400063
PM 1922342
DA 2026-03-10
ER

PT J
AU GORR, T
   KLEINSCHMIDT, T
   FRICKE, H
AF GORR, T
   KLEINSCHMIDT, T
   FRICKE, H
TI CLOSE TETRAPOD RELATIONSHIPS OF THE COELACANTH LATIMERIA INDICATED BY HEMOGLOBIN SEQUENCES
SO NATURE
LA English
DT Article
ID hemoglobin; affinity; parsimony; proteins
AB THE origin of tetrapods has been debated for many years. In traditional systematics, the extinct lobe-finned bony fish (Rhipidistia) are regarded as the closest relatives of tetrapods 1. Among living fish, the coelacanth Latimeria chalumnae (Actinistia) 2-4, which is the only recent representative of the Crossopterygii (Actinistia and Rhipidistia), the lungfish (Dipnoi) 5-8 and ray-finned fish (Actinopterygii) 9, 10, have each been considered as sister-groups of the tetrapods. We have now determined the sequence of the alpha and beta-globin chains of coelacanth haemoglobin and compared them with all known haemoglobins of bony and cartilaginous fish as well as those of tadpoles and adult amphibians. Haemoglobins of bony fish match more closely those of larval than adult amphibians. The beta-chains of Latimeria match those of tadpoles more closely (54%) than do those of any other fish, whereas the alpha-chains of Latimeria (45.4%), and especially of teleosts (49.2%), are closer to those of larval amphibians than are those of lungfish (39.8%). If only synapomorphous sequence matches (those at derived positions shared by one bony fish and tadpoles but not by any other bony fish) are considered, both Latimeria globin chains have distinctly more identities with phase of tadpoles than do those of any bony fish. Thus the primary structure of Latimeria haemoglobin indicates that the coelacanth is the closest living relative of tetrapods.
C1 MAX PLANCK INST BIOCHEM, W-8033 MARTINSRIED, GERMANY.
   MAX PLANCK INST VERHALTENSPHYSIOL, W-8131 SEEWIESEN, GERMANY.
C3 Max Planck Society; Max Planck Society
NR 30
TC 75
Z9 80
U1 0
U2 9
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 394
EP 397
DI 10.1038/351394a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600054
PM 2034288
DA 2026-03-10
ER

PT J
AU DALEMANS, W
   BARBRY, P
   CHAMPIGNY, G
   JALLAT, S
   DOTT, K
   DREYER, D
   CRYSTAL, RG
   PAVIRANI, A
   LECOCQ, JP
   LAZDUNSKI, M
AF DALEMANS, W
   BARBRY, P
   CHAMPIGNY, G
   JALLAT, S
   DOTT, K
   DREYER, D
   CRYSTAL, RG
   PAVIRANI, A
   LECOCQ, JP
   LAZDUNSKI, M
TI ALTERED CHLORIDE-ION CHANNEL KINETICS ASSOCIATED WITH THE DELTA-F508 CYSTIC-FIBROSIS MUTATION
SO NATURE
LA English
DT Article
ID transmembrane conductance regulator; epithelial-cells; expression; gene; cl; identification; transport; membrane
AB CYSTIC fibrosis is associated with a defect in epithelial chloride ion transport (reviewed in refs 1, 2) which is caused by mutations in a membrane protein called CFTR (cystic fibrosis transmembrane conductance regulator) 3.  Heterologous expression of CFTR produces cyclicAMP-sensitive Cl--channel activity 4-7.  Deletion of phenylalanine at amino-acid position 508 in CFTR (DELTA-F508 CFTR) is the most common mutation in cystic fibrosis 8.  It has been proposed that this mutation prevents glycoprotein maturation and its transport to its normal cellular location 9.  We have expressed both CFIR and DELTA-F508 CFTR in Vero cells using recombinant vaccinia virus. Although far less DELTA-F508 CFTR reached the plasma membrane than normal CFTR, sufficient DELTA-F508 CFTR was expressed at the plasma membrane to permit functional analysis. DELTA-F508 CFIR expression induced a reduced activity of the cAMP-activated Cl- channel, with conductance, anion selectivity and open-time kinetics similar to those of CFIR, but with much greater closed times, resulting in a large decrease of open probability. The DELTA-F508 mutation thus seems to have two major consequences, an abnormal translocation of the CFTR protein which limits membrane insertion, and an abnormal function in mediating Cl- transport.
C1 INST PHARMACOL MOLEC & CELLULAIRE,660 ROUTE LUCIOLES,SOPHIA ANTIPOLIS,F-06560 VALBONNE,FRANCE.
   TRANSGENE SA,F-67082 STRASBOURG,FRANCE.
   NHLBI,PULM BRANCH,BETHESDA,MD 20892.
C3 Transgene SA; National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI)
NR 23
TC 638
Z9 817
U1 1
U2 56
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 526
EP 528
DI 10.1038/354526a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100015
PM 1722027
DA 2026-03-10
ER

PT J
AU BAKAN, S
   CHLOND, A
   CUBASCH, U
   FEICHTER, J
   GRAF, H
   GRASSL, H
   HASSELMANN, K
   KIRCHNER, I
   LATIF, M
   ROECKNER, E
   SAUSEN, R
   SCHLESE, U
   SCHRIEVER, D
   SCHULT, I
   SCHUMANN, U
   SIELMANN, F
   WELKE, W
AF BAKAN, S
   CHLOND, A
   CUBASCH, U
   FEICHTER, J
   GRAF, H
   GRASSL, H
   HASSELMANN, K
   KIRCHNER, I
   LATIF, M
   ROECKNER, E
   SAUSEN, R
   SCHLESE, U
   SCHRIEVER, D
   SCHULT, I
   SCHUMANN, U
   SIELMANN, F
   WELKE, W
TI CLIMATE RESPONSE TO SMOKE FROM THE BURNING OIL-WELLS IN KUWAIT
SO NATURE
LA English
DT Article
ID general-circulation model; simulations; aerosols; snow
AB The response of the global climate system to smoke from burning oil wells in Kuwait is investigated in a series of numerical experiments using a coupled atmosphere-ocean general circulation model with an interactive soot transport model and extended radiation scheme.  The results  show a decrease in surface air temperature of approximately 4-degrees-C in the Gulf region.  Outside this region the changes are small and statistically insignificant.  No weakening of the Indian summer monsoon is observed.
C1 MAX PLANCK INST METEOROL,BUNDESSTR 55,W-2000 HAMBURG 13,GERMANY.
   DFVLR,INST PHYS ATMOSPHARE,W-8031 OBERPFAFFENHOFEN,GERMANY.
   UNIV HAMBURG,INST METEOROL,W-2000 HAMBURG 13,GERMANY.
C3 Max Planck Society; Helmholtz Association; German Aerospace Centre (DLR); University of Hamburg
NR 29
TC 72
Z9 77
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 367
EP 371
DI 10.1038/351367a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600046
DA 2026-03-10
ER

PT J
AU MACHETEL, P
   WEBER, P
AF MACHETEL, P
   WEBER, P
TI INTERMITTENT LAYERED CONVECTION IN A MODEL MANTLE WITH AN ENDOTHERMIC PHASE-CHANGE AT 670 KM
SO NATURE
LA English
DT Article
ID earth
AB It is not yet known whether convection in the Earth's mantle occurs in cells that extend throughout the entire depth of the mantle, or if the upper and lower mantle convect in independent layers; both possibilities seem to be consistent with geochemical and seismological observations 1-4.  It is generally accepted, however, that the seismologically observed boundary between the upper and lower mantle at 670 km depth arises from the endothermic phase change, spinel --> perovskite + MgO.  Here we investigate the results of including this phase change in a model of mantle convection.  For realism and to eliminate scaling problems, our calculations use commonly accepted values of geophysical parameters.  For a Clapeyron slope gamma = -2 x 10(6), a value close to experimental results and theoretical expectations, we observe local intermittent mixing between the upper and lower mantle.  Such behaviour may offer a way to reconcile the existence of geophysical evidence for both whole-mantle and layered convection.
RP MACHETEL, P (corresponding author), CNRS,RECH GEODESIE SPATIALE GRP,UPR 234,18 AVE E BELIN,F-31055 TOULOUSE,FRANCE.
NR 23
TC 294
Z9 309
U1 0
U2 23
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 55
EP 57
DI 10.1038/350055a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300062
DA 2026-03-10
ER

PT J
AU MAURY, V
AF MAURY, V
TI THE ROLE OF ROCK MECHANICS IN OIL AND GAS EXPLORATION
SO NATURE
LA English
DT Article
ID stress; breakouts; borehole
AB Oil and gas exploration and production is the mainstay of Elf Aquitaine's business.  This article describes how advances in the study of rock mechanics are applied in the field.
RP MAURY, V (corresponding author), SOC NATL ELF AQUITAINE,CSJF,26 AVE LILAS,F-64018 PAU,FRANCE.
NR 41
TC 3
Z9 4
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 8
EP 10
DI 
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100006
DA 2026-03-10
ER

PT J
AU CREEL, SR
   MONFORT, SL
   WILDT, DE
   WASER, PM
AF CREEL, SR
   MONFORT, SL
   WILDT, DE
   WASER, PM
TI SPONTANEOUS LACTATION IS AN ADAPTIVE RESULT OF PSEUDOPREGNANCY
SO NATURE
LA English
DT Article
ID dwarf mongoose; estrous-cycle; progesterone; pregnancy; reproduction; estradiol; infants; dog
AB LACTATION is almost exclusively associated with pregnancy and giving birth.  Although lactation can be induced without a preceding pregnancy in some species, this requires exogenous hormones, artificially intense or extended suckling or both 1, 2.  Spontaneous lactation, lactation by females that have neither been pregnant nor experimentally manipulated, is extremely unusual among eutherians 3-8.  Among nondomesticated animals, spontaneous lactation has been observed repeatedly only in the dwarf mongoose Helogale parvula 9.  We report here spontaneous lactation by free-living dwarf mongooses using data on urinary oestrogen conjugate concentrations (n = 560, 65 females) and body weight (n = 3,096, 25 females) from a population in Serengeti National Park, Tanzania.  We use demographic data from this population to demonstrate that spontaneous lactation, and thus the endocrine phenomena that induce it, increase the evolutionary fitness of lactating females.
C1 SMITHSONIAN INST,NATL ZOOL PK,CTR CONSERVAT & RES,ENDOCRINE RES LAB,FRONT ROYAL,VA 22630.
C3 Smithsonian Institution; Smithsonian National Zoological Park & Conservation Biology Institute
RP CREEL, SR (corresponding author), PURDUE UNIV,DEPT BIOL SCI,W LAFAYETTE,IN 47907, USA.
NR 24
TC 74
Z9 80
U1 1
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 660
EP 662
DI 10.1038/351660a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200069
PM 2052092
DA 2026-03-10
ER

PT J
AU DAVIS, AM
   OLSEN, EJ
AF DAVIS, AM
   OLSEN, EJ
TI PHOSPHATES IN PALLASITE METEORITES AS PROBES OF MANTLE PROCESSES IN SMALL PLANETARY BODIES
SO NATURE
LA English
DT Article
ID rare-earth elements; pu-244; iron
AB THE stony-iron pallasite meteorites, which are generally believed to come from the core-mantle boundaries of asteroids, contain small quantities of phosphate minerals. Here we use trace element analyses of these phosphates to investigate the magmatic history of the silicate portions of pallasites. In Eagle Station and seven other pallasites, the phosphates have relatively low concentrations of rare earth elements (REE) and are strongly enriched in heavy relative to light REE. These patterns are consistent with formation of phosphate by subsolidus reactions between metal and silicate, in which phosphate inherits the REE pattern of olivine. In Springwater and Santa Rosalia, calcium-rich phosphates have higher concentrations of REE, are enriched in light relative to heavy REE and have negative europium anomalies. These patterns are consistent with crystallization of phosphate from a europium-depleted chondritic liquid. This is unlikely to have happened near the base of the differentiating parent-body mantle, because phosphates are late-crystallizing phases; this suggests that some pallasites may come from regions of their parent bodies much nearer the surface than the core-mantle boundary.
C1 UNIV CHICAGO,DEPT GEOPHYS SCI,CHICAGO,IL 60637.
C3 University of Chicago
RP DAVIS, AM (corresponding author), UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637, USA.
NR 19
TC 46
Z9 51
U1 1
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 637
EP 640
DI 10.1038/353637a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200061
DA 2026-03-10
ER

PT J
AU DALLOS, P
   EVANS, BN
   HALLWORTH, R
AF DALLOS, P
   EVANS, BN
   HALLWORTH, R
TI NATURE OF THE MOTOR ELEMENT IN ELECTROKINETIC SHAPE CHANGES OF COCHLEAR OUTER HAIR-CELLS
SO NATURE
LA English
DT Article
ID mechanical responses
AB IT is the prevailing notion that cochlear outer hair cells function as mechanical effectors as well as sensory receptors 1-3.  Electrically induced changes in the shape of mammalian outer hair cells 4,5, studied in vitro, are commonly assumed to represent an aspect of their effector process that may occur in vivo.  The nature of the motile process is obscure, even though none of the established cellular motors can be involved 6.  Although it is known that the motile response is under voltage control 7, it is uncertain whether the stimulus is a drop in the voltage along the long axis of the cell or variation in the transmembrane potential.  We have now performed experiments with cells partitioned in differing degrees between two chambers.  Applied voltage stimulates the cell membrane segments in opposite polarity to an amount dependent on the partitioning.  The findings show, in accordance with previous suggestions 6,8, that the driving stimulus is a local transmembrane voltage drop and that the cellular motor consists of many independent elements, distributed along the cell membrane and its associated cortical structures.  We further show that the primary action of the motor elements is along the longitudinal dimension of the cell without necessarily involving changes in intracellular hydrostatic pressure.  This establishes the outer hair cell motor as unique among mechanisms that control cell shape 9.
C1 NORTHWESTERN UNIV,DEPT NEUROBIOL & PHYSIOL,EVANSTON,IL 60208.
C3 Northwestern University
RP DALLOS, P (corresponding author), NORTHWESTERN UNIV,HUGH KNOWLES CTR,AUDITORY PHYSIOL LAB,EVANSTON,IL 60208, USA.
NR 26
TC 195
Z9 211
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 155
EP 157
DI 10.1038/350155a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500059
PM 2005965
DA 2026-03-10
ER

PT J
AU HALLIGAN, PW
   MARSHALL, JC
AF HALLIGAN, PW
   MARSHALL, JC
TI LEFT NEGLECT FOR NEAR BUT NOT FAR SPACE IN MAN
SO NATURE
LA English
DT Article
AB IT has been suggested that, among the many visual areas of the human brain, there might be one set of spatial maps specialized for 'near' (peripersonal) and another for 'far' (extrapersonal) space.  A distinction between 'grasping distance' and 'walking distance' 1, or between a 'reaching field' and a pointing or throwing field 2 has commonly been made.  Evidence for such a division has been found in monkeys.  Unilateral ablation of the frontal eye field (area 8) produces a more prominent inattention (or 'neglect') for objects in contralesional far space than in near space; by contrast, unilateral ablation of frontal area 6, which receives direct projections from area 7b (the rostral part of the inferior parietal lobules) results in inattention to visual stimuli limited to contralesional near space 3.  Despite predictions that comparable dissociations should be found in man 4, there has been no convincing evidence.  We report here such evidence in a patient with a unilateral right hemisphere stroke.  Within peripersonal space, he showed severe left visuo-spatial neglect on conventional tests, including the highly sensitive task of line bisection.  When line bisection was performed in extrapersonal space, neglect was abolished or attenuated.
C1 RIVERMEAD REHABIL CTR,OXFORD OX1 4XD,ENGLAND.
RP HALLIGAN, PW (corresponding author), UNIV OXFORD,RADCLIFFE INFIRM,DEPT CLIN NEUROL,NEUROPSYCHOL UNIT,OXFORD OX2 6HE,ENGLAND.
NR 12
TC 427
Z9 450
U1 0
U2 26
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 498
EP 500
DI 10.1038/350498a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300050
PM 2014049
DA 2026-03-10
ER

PT J
AU MERCER, JA
   SEPERACK, PK
   STROBEL, MC
   COPELAND, NG
   JENKINS, NA
AF MERCER, JA
   SEPERACK, PK
   STROBEL, MC
   COPELAND, NG
   JENKINS, NA
TI NOVEL MYOSIN HEAVY-CHAIN ENCODED BY MURINE DILUTE COAT COLOR LOCUS
SO NATURE
LA English
DT Article
ID intestinal microvillus; messenger-rna; sequence; protein; gene; complex; cloning; actin; dna; phenotype
AB HUNDREDS of murine dilute mutations have been identified and analysed, making dilute one of the best genetically characterized of all mammalian loci.  The recessive dilute (d) coat colour mutation carried by many inbred strains of mice produces a lightening of coat colour, caused by an abnormal adendritic melanocyte morphology that results in an uneven release of pigment granules into the developing hair shaft 1,2.  Most dilute alleles (dilute-lethal) also produce a neurological defect, characterized by convulsions and opisthotonus, apparent at 8-10 days of age and continuing until the death of the animal at 2-3 weeks of age 3. The discovery that the original dilute allele (now termed dilute-viral or d(V)) is the result of the integration of an ecotropic murine leukaemia provirus 4 has allowed the cloning of genomic DNA 5,6 and in this study complementary DNA, from the dilute locus.  The predicted dilute amino-acid sequence indicates that dilute encodes a novel type of myosin heavy chain, with a tail, or C-terminal, region that has elements of both type II (alpha-helical coiled-coil) and type I (non-coiled-coil) myosin heavy chains.  Dilute transcripts are differentially expressed in both embryonic and adult tissues and are very abundant in neurons of the central nervous system, cephalic ganglia, and spinal ganglia.  These results suggest an important role for the dilute gene product in the elaboration, maintenance, or function of cellular processes of melanocytes and neurons.
C1 NCI,FREDERICK CANC RES & DEV CTR,ABL,BASIC RES PROGRAM,MAMMALIAN GENET LAB,FREDERICK,MD 21702.
C3 Science Applications International Corporation (SAIC); SAIC-Frederick; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI)
NR 32
TC 499
Z9 542
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 709
EP 713
DI 10.1038/349709a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700052
PM 1996138
DA 2026-03-10
ER

PT J
AU FELLER, DC
   DELACRUZ, VF
AF FELLER, DC
   DELACRUZ, VF
TI IDENTIFYING ANTIGENIC T-CELL SITES
SO NATURE
LA English
DT Article
ID major histocompatibility complex; recognition; prediction; sequence
RP FELLER, DC (corresponding author), MEDLMMUNE INC, 19 FIRSTFIELD RD, GAITHERSBURG, MD 20878 USA.
NR 17
TC 68
Z9 80
U1 0
U2 1
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 720
EP 721
DI 10.1038/349720a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700056
PM 1705016
DA 2026-03-10
ER

PT J
AU SMITH, LM
AF SMITH, LM
TI HIGH-SPEED DNA SEQUENCING BY CAPILLARY GEL-ELECTROPHORESIS
SO NATURE
LA English
DT Article
AB Capillary gel electrophoresis with fluorescence detection is a new technique for rapid DNA sequence analysis.  The state of this technology and the potential for its future use are discussed.
RP SMITH, LM (corresponding author), UNIV WISCONSIN,DEPT CHEM,MADISON,WI 53706, USA.
NR 14
TC 67
Z9 75
U1 0
U2 18
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 812
EP 813
DI 10.1038/349812a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600064
PM 2000151
DA 2026-03-10
ER

PT J
AU GLOERSEN, P
   CAMPBELL, WJ
AF GLOERSEN, P
   CAMPBELL, WJ
TI RECENT VARIATIONS IN ARCTIC AND ANTARCTIC SEA-ICE COVERS
SO NATURE
LA English
DT Article
ID carbon-dioxide; temperature; variability
AB Variations in the extents of sea-ice cover at the poles and the areas of open water enclosed within them were observed every other day during the interval 1978-1987 by a satellite-borne scanning multispectral microwave radiometer. A band-limited regression technique shows that the trends in coverage of the Arctic and Antarctic sea-ice packs are not the same. During these nine years, there are significant decreases in ice extent and open-water areas within the ice cover in the Arctic, whereas in the Antarctic, there are no significant trends.
C1 UNIV PUGET SOUND,US GEOL SURVEY,ICE & CLIMATE PROJECT,TACOMA,WA 98416.
C3 United States Department of the Interior; United States Geological Survey
RP GLOERSEN, P (corresponding author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,CODE 971,GREENBELT,MD 20771, USA.
NR 23
TC 113
Z9 117
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 33
EP 36
DI 10.1038/352033a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800060
DA 2026-03-10
ER

PT J
AU BAI, T
   STURROCK, PA
AF BAI, T
   STURROCK, PA
TI THE 154-DAY AND RELATED PERIODICITIES OF SOLAR-ACTIVITY AS SUBHARMONICS OF A FUNDAMENTAL PERIOD
SO NATURE
LA English
DT Article
ID flare occurrence rate; behavior
AB IN 1984 a periodicity of 154 days was found in the record of solar flare activity 1 from 1980 to 1983.  Since then, the same periodicity has been found in many different measures of solar flare activity during cycle 21 (soft X-ray peak flux 1; hard X-ray emission 2,3; H-alpha flare activity 4; microwave peak flux 5; production of interplanetary electrons 6 and protons 7; 10-cm radio flux 8) as well as in sunspot area 9,10.  The cause of this 154-day periodicity, which has also been discovered in solar cycles 19 and 20 (refs 7, 11) remains unknown, but a suggestion that it was related to enhanced flare activity in certain longitude bands has been ruled out 3.  Here we show that periodicities of 51, 78, 104 and 129 days, in addition to the 154-day period, can often be detected in flare and sunspot records.  These periods are close to integral multiples (by factors of 2, 3, 4, 5 and 6( of 25.8 days, suggesting that they are subharmonics of a fundamental period.
RP BAI, T (corresponding author), STANFORD UNIV,CTR SPACE SCI & ASTROPHYS,STANFORD,CA 94305, USA.
NR 22
TC 97
Z9 100
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 141
EP 143
DI 10.1038/350141a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500052
DA 2026-03-10
ER

PT J
AU UYEDA, TQP
   WARRICK, HM
   KRON, SJ
   SPUDICH, JA
AF UYEDA, TQP
   WARRICK, HM
   KRON, SJ
   SPUDICH, JA
TI QUANTIZED VELOCITIES AT LOW MYOSIN DENSITIES IN AN INVITRO MOTILITY ASSAY
SO NATURE
LA English
DT Article
ID single kinesin molecules; step size; actin; movement; muscle
AB An in vitro motility assay has been developed in which single actin filaments move on one or a few heavy meromyosin (HMM) molecules. This movement is slower than when many HMM molecules are involved, in contrast to analogous experiments with microtubules and kinesin. Frequency analysis shows that sliding speeds distribute around integral multiples of a unitary velocity. This discreteness may be due to differences in the numbers of HMM molecules interacting with each actin filament, where the unitary velocity reflects the activity of one HMM molecule. The value of the unitary velocity predicts a step size of 5-20 nm per ATP, which is consistent with the conventional swinging crossbridge model for myosin function.
C1 STANFORD UNIV,MED CTR,SCH MED,DEPT DEV BIOL,FAIRCHILD CTR,STANFORD,CA 94305.
C3 Stanford University
RP UYEDA, TQP (corresponding author), STANFORD UNIV,MED CTR,SCH MED,DEPT CELL BIOL,FAIRCHILD CTR,STANFORD,CA 94305, USA.
NR 19
TC 166
Z9 175
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 307
EP 311
DI 10.1038/352307a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900060
PM 1852205
DA 2026-03-10
ER

PT J
AU KEMP, DS
   BOYD, JG
   MUENDEL, CC
AF KEMP, DS
   BOYD, JG
   MUENDEL, CC
TI THE HELICAL S-CONSTANT FOR ALANINE IN WATER DERIVED FROM TEMPLATE-NUCLEATED HELICES
SO NATURE
LA English
DT Article
ID immunogenic peptide-fragments; rotating-frame; alpha-helix; proteins; h-1-nmr; spectroscopy
AB FORMATION of alpha-helices from disordered polypeptides depends on the degree to which amino acids favour the helical state. The folding of helical oligopeptides can be modelled by two parameters: sigma which reflects helix initiation and s which reflects propagation of a pre-existing helix and measures helical bias 1,2.  Scheraga has reported s values for oligopeptides of about 1.1, implying a weak helical bias for amino-acid residues 3.  By contrast, certain helical peptides studied by Baldwin seem to require much larger s values for alanine 4.  Resolution of this inconsistency requires experiments that disentangle the ease of propagation from that of initiation. In this study varying lengths of polyalanine are linked to a 'template' that initiates helical structure and permits study solely of propagation. We report here that the s value for alanine in water is close to 1, supporting the earlier results of Scheraga but not the more recent results of Baldwin.
RP KEMP, DS (corresponding author), MIT,DEPT CHEM,ROOM 18-584,CAMBRIDGE,MA 02139, USA.
NR 21
TC 134
Z9 143
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 451
EP 454
DI 10.1038/352451a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600072
PM 1861726
DA 2026-03-10
ER

PT J
AU EZEKOWITZ, RAB
   WILLIAMS, DJ
   KOZIEL, H
   ARMSTRONG, MYK
   WARNER, A
   RICHARDS, FF
   ROSE, RM
AF EZEKOWITZ, RAB
   WILLIAMS, DJ
   KOZIEL, H
   ARMSTRONG, MYK
   WARNER, A
   RICHARDS, FF
   ROSE, RM
TI UPTAKE OF PNEUMOCYSTIS-CARINII MEDIATED BY THE MACROPHAGE MANNOSE RECEPTOR
SO NATURE
LA English
DT Article
ID invitro; zymosan; phagocytosis
AB HUMAN exposure to Pneumocystis carinii is common 1,2 but, in the absence of acquired 3 or genetic 4 dysfunction of either cellular or humoral immunity, exposure rarely leads to illness. Although alveolar macrophages can degrade P. carinii 5,6, macrophage receptors involved in P. carinii recognition have not been clearly defined. Characterization of a predominant surface glycoprotein of the high mannose type 7,8 led us to investigate the role of the macrophage mannose receptor in this process. We report here that binding and uptake of cultured rat P. carinii by human and rat alveolar macrophages is reduced by 90% in the presence of competitive inhibitors of mannose receptor activity and by adherence of alveolar macrophages to mannan-coated surfaces. Further, only those COS cells transfected with the human macrophage mannose receptor complementary DNA that express surface mannose receptors bind and ingest P. carinii. These studies establish that the macrophage mannose receptor is sufficient for uptake of P. carinii and emphasize the role of the alveolar macrophage in first-line host defence against P. carinii.
C1 HARVARD UNIV, SCH MED, DANA FARBER CANC INST, DEPT PEDIAT, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, MACARTHUR CTR MOLE PARASITOL, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, DEPT INTERNAL MED, PULM & CRIT CARE SECT, BOSTON, MA 02115 USA.
   HARVARD UNIV, SCH MED, DEPT EPIDEMIOL & PUBL HLTH, BOSTON, MA 02115 USA.
   HARVARD UNIV, NEW ENGLAND DEACONESS HOSP, SCH MED, DIV PULM & CRIT CARE MED, BOSTON, MA 02215 USA.
   HARVARD UNIV, SCH PUBL HLTH, DEPT RESP BIOL, BOSTON, MA 02115 USA.
C3 Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Dana-Farber Cancer Institute; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; Harvard University; Harvard T.H. Chan School of Public Health
RP EZEKOWITZ, RAB (corresponding author), CHILDRENS HOSP MED CTR, DIV HEMATOL ONCOL, BOSTON, MA 02115 USA.
NR 21
TC 391
Z9 422
U1 0
U2 17
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 155
EP 158
DI 10.1038/351155a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500054
PM 1903183
DA 2026-03-10
ER

PT J
AU KRAMER, H
   CAGAN, RL
   ZIPURSKY, SL
AF KRAMER, H
   CAGAN, RL
   ZIPURSKY, SL
TI INTERACTION OF BRIDE OF SEVENLESS MEMBRANE-BOUND LIGAND AND THE SEVENLESS TYROSINE-KINASE RECEPTOR
SO NATURE
LA English
DT Article
ID homophilic adhesion molecule; growth-factor receptor; drosophila retina; egf receptor; cell fate; signal transduction; mesoderm induction; putative receptor; pattern-formation; fasciclin-iii
AB During development of the Drosophila retina, the R8 photoreceptor neuron induces a neighbouring cell to assume an R7 cell fate. Genetic data suggest that the induction is mediated by two transmembrane proteins encoded by bride of sevenless and sevenless. A direct interaction between these two proteins was demonstrated by the heterotypic aggregation of cell lines expressing them. In the developing eye the sevenless-dependent internalization of bride of sevenless by the R7 precursor cell provides evidence for a direct interaction between these two proteins in vivo.
C1 UNIV CALIF LOS ANGELES, INST MOLEC BIOL, LOS ANGELES, CA 90024 USA.
C3 University of California System; University of California Los Angeles
RP KRAMER, H (corresponding author), UNIV CALIF LOS ANGELES, SCH MED, DEPT BIOL CHEM, LOS ANGELES, CA 90024 USA.
NR 55
TC 292
Z9 314
U1 0
U2 5
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 207
EP 212
DI 10.1038/352207a0
PG 6
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500053
PM 1857416
DA 2026-03-10
ER

PT J
AU GIBBONS, WM
   SHANNON, PJ
   SUN, ST
   SWETLIN, BJ
AF GIBBONS, WM
   SHANNON, PJ
   SUN, ST
   SWETLIN, BJ
TI SURFACE-MEDIATED ALIGNMENT OF NEMATIC LIQUID-CRYSTALS WITH POLARIZED LASER-LIGHT
SO NATURE
LA English
DT Article
AB THE control of molecular alignment in liquid-crystal phases at macroscopic scales has been investigated extensively because of its importance in optical or optoelectronic applications, such as liquid-crystal displays 1.  It is well established that liquid crystals can be aligned by an applied electric field, a magnetic field, a shear-flow field, mechanical grooving of the substrate surface or stretching of liquid-crystal polymer thin films 2,3.  Here we report a new mechanism for liquid-crystal alignment that uses polarized laser light.  We find that nematic liquid crystals in an illuminated region become oriented perpendicular to the direction of the electric-field polarization of the laser and remain aligned in the absence of the laser radiation.  The liquid crystals can be reoriented again by subsequent illumination.  This technique might have applications for large-area displays, optical memories, binary optics, adaptive optics and molecular micro-assembly.
RP GIBBONS, WM (corresponding author), HERCULES INC,RES CTR,WILMINGTON,DE 19894, USA.
NR 5
TC 1172
Z9 1290
U1 4
U2 243
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 49
EP 50
DI 10.1038/351049a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300054
DA 2026-03-10
ER

PT J
AU BRAITHWAITE, D
   BEAUGNON, E
   TOURNIER, R
AF BRAITHWAITE, D
   BEAUGNON, E
   TOURNIER, R
TI MAGNETICALLY CONTROLLED CONVECTION IN A PARAMAGNETIC FLUID
SO NATURE
LA English
DT Article
AB CONVECTION in a liquid is important for problems involving heat transfer and crystal growth from a melt. The driving force for convection is usually the density difference between hot and cold regions of the fluid. If the fluid has a magnetic susceptibility that varies with temperature, magnetic forces, rather than buoyancy, can be made to drive convective motion. Studies on ferrofluids (suspensions of ferromagnetic particles 1) have shown that magnetic convection can be initiated in a homogeneous magnetic field 2,3 and enhanced in a field gradient 4.  We show here that the strong magnetic fields available f rom superconducting magnets can be used to induce magnetic convection in normal paramagnetic fluids, such as solutions of paramagnetic salts or melts of paramagnetic solids. We have used a magnetic field both to enhance and to suppress buoyancy-driven convection in a solution of gadolinium nitrate, the sign of the effect depending on the relative orientation of magnetic-field and temperature gradients. The effect might be exploited in heat-transfer devices or to control microstructures in crystal growth.
RP BRAITHWAITE, D (corresponding author), CNRS,CTR RECH TRES BASSES TEMP,BP 166,F-38042 GRENOBLE 9,FRANCE.
NR 8
TC 236
Z9 259
U1 2
U2 57
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 134
EP 136
DI 10.1038/354134a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000054
DA 2026-03-10
ER

PT J
AU MANCHESTER, RN
   LYNE, AG
   ROBINSON, C
   DAMICO, N
   BAILES, M
   LIM, J
AF MANCHESTER, RN
   LYNE, AG
   ROBINSON, C
   DAMICO, N
   BAILES, M
   LIM, J
TI DISCOVERY OF 10-MILLISECOND PULSARS IN THE GLOBULAR-CLUSTER 47-TUCANAE
SO NATURE
LA English
DT Article
ID eclipsing millisecond pulsar; radio pulsars; systems; m15
AB IN the past four years a total of 13 millisecond pulsars have been found in 12 different globular clusters. These pulsars are believed to be old neutron stars that have been spun up ('recycled') in low-mass X-ray binary systems 1, although some may have been formed by the accretion-induced collapse of white dwarfs in binaries 2. The globular cluster 47 Tucanae has an especially dense core, and is therefore a likely site for millisecond pulsar formation. Using the Parkes radiotelescope, we have now detected ten additional millisecond pulsars in 47 Tuc, more than half of which are members of binary systems. Almost half of the known millisecond pulsars and more than a quarter of the known binary pulsars now reside in this one cluster.
C1 UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND.
   UNIV PALERMO,IST FIS,I-90134 PALERMO,ITALY.
   CNR,IST RADIOASTRON,I-40126 BOLOGNA,ITALY.
   MACQUARIE UNIV,SCH MATH PHYS COMP & ELECTR,N RYDE,NSW 2113,AUSTRALIA.
C3 University of Manchester; University of Palermo; Istituto Nazionale Astrofisica (INAF); Consiglio Nazionale delle Ricerche (CNR); Macquarie University
RP MANCHESTER, RN (corresponding author), CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA.
NR 18
TC 155
Z9 170
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 219
EP 221
DI 10.1038/352219a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500055
DA 2026-03-10
ER

PT J
AU PRICE, M
   LEMAISTRE, M
   PISCHETOLA, M
   DILAURO, R
   DUBOULE, D
AF PRICE, M
   LEMAISTRE, M
   PISCHETOLA, M
   DILAURO, R
   DUBOULE, D
TI A MOUSE GENE RELATED TO DISTAL-LESS SHOWS A RESTRICTED EXPRESSION IN THE DEVELOPING FOREBRAIN
SO NATURE
LA English
DT Article
ID limb development; drosophila; murine; homeodomain; embryogenesis; organization; hindbrain; pattern; en-1
AB MANY genes known to be involved in embryogenesis and morphogenesis of the fruitfly Drosophila melanogaster encode proteins with a highly conserved region of 60 amino acids called the homeodomain 1.  Mammalian counterparts for most of these genes have been identified, including those homologous to the Drosophila homeotic genes 2,3 or to genes such as evenskipped 4, engrailed 5,6 or caudal 7.  We have isolated a murine homeobox gene that encodes a homeodomain similar to that encoded by the Drosophila Distalless (Dll) gene 8.  Dll has a crucial role in Drosophila limb morphogenesis, partially specifying pattern along the proximo-distal axis of the limb 8,9. The murine counterpart is expressed in a restricted region of the developing brain, within the diencephalon and the adjacent telencephalic regions.
RP PRICE, M (corresponding author), EUROPEAN MOLEC BIOL LAB,POSTFACH 102209,W-6900 HEIDELBERG,GERMANY.
NR 22
TC 278
Z9 295
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 748
EP 751
DI 10.1038/351748a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100065
PM 1676488
DA 2026-03-10
ER

PT J
AU CHAKRABARTTY, A
   SCHELLMAN, JA
   BALDWIN, RL
AF CHAKRABARTTY, A
   SCHELLMAN, JA
   BALDWIN, RL
TI LARGE DIFFERENCES IN THE HELIX PROPENSITIES OF ALANINE AND GLYCINE
SO NATURE
LA English
DT Article
ID occurring amino-acids; coil stability-constants; forming tendency; alpha-helices; peptides; water; parameters
AB THE standard view of alpha-helix formation in water, based on helix propensities determined by the host-guest method 1,2, is that differences in helix propensity among the amino acids are small, except for proline 3, and that the average value of the helix propagation parameter s is near 1.  A contradictory view of alpha-helix formation in water is emerging from substitution experiments with short, unique-sequence peptides that contain only naturally occurring amino acids 4-9.  Short peptides that contain only alanine and lysine, or alanine and glutamate, form surprisingly stable monomeric helices in water 9 and substitution of a single alanine residue by another amino acid in these or related peptides produces a wide range of changes in helix content, depending on which amino acid is substituted for alanine 4-6,8.  We show here that the ratio of the helix propensities of alanine to glycine is large, about 100, in substitution experiments with a 17-residue reference peptide containing alanine and lysine.  The helix propensity is identified with s, the helix propagation parameter of the statistical mechanics model for alpha-helix formation, and the results are interpreted by the Lifson-Roig theory 10.  Single alanine --> glycine substitutions have been made at a series of positions in individual peptides.  The helix-destabilizing effect of an Ala --> Gly substitution depends strongly on its position in the helix, as predicted by the Lifson-Roig theory if the ratio of s values for Ala:Gly is large.
C1 UNIV OREGON,INST MOLEC BIOL,EUGENE,OR 97403.
C3 University of Oregon
RP CHAKRABARTTY, A (corresponding author), STANFORD UNIV,MED CTR,SCH MED,DEPT BIOCHEM,STANFORD,CA 94305, USA.
NR 20
TC 322
Z9 357
U1 0
U2 27
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 13
PY 1991
VL 351
IS 6327
BP 586
EP 588
DI 10.1038/351586a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FR034
UT WOS:A1991FR03400065
PM 2046766
DA 2026-03-10
ER

PT J
AU BENJAMIN, RJ
   MADRIGAL, JA
   PARHAM, P
AF BENJAMIN, RJ
   MADRIGAL, JA
   PARHAM, P
TI PEPTIDE BINDING TO EMPTY HLA-B27 MOLECULES OF VIABLE HUMAN-CELLS
SO NATURE
LA English
DT Article
ID toxic lymphocytes-t; ankylosing-spondylitis; monoclonal-antibody; antigen; hla; association; recognition; mutagenesis; chains; virus
AB INTRACELLULAR binding of antigenic peptides by polymorphic class I major histocompatibility complex molecules creates the ligands recognized by receptors of CD8+ T cells 1.  Previously described in vitro assays of peptide binding to class I molecules have been limited by either the low proportion of accessible binding sites or the lack of allelic specificity 2-6.  Here we describe a system in which the human class I molecule HLA-B27 binds considerable amounts of an influenza peptide with precise allelic discrimination.  Binding requires viable cells, is stimulated by gamma-interferon and is inhibited by brefeldin A.  Our results are consistent with the presence of fairly stable 'empty' HLA-B27 molecules at the cell surface.  By contrast, analysis of the binding of a second influenza peptide indicates that empty HLA-Aw68 molecules are relatively short-lived.  We speculate that HLA-B27 might bind extracellular peptides in vivo and that this property could underlie its association with autoimmune disease.
C1 STANFORD UNIV,DEPT MICROBIOL & IMMUNOL,STANFORD,CA 94305.
C3 Stanford University
RP BENJAMIN, RJ (corresponding author), STANFORD UNIV,DEPT CELL BIOL,STANFORD,CA 94305, USA.
NR 35
TC 151
Z9 157
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 74
EP 77
DI 10.1038/351074a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300064
PM 2027387
DA 2026-03-10
ER

PT J
AU KUHLBUSCH, TA
   LOBERT, JM
   CRUTZEN, PJ
   WARNECK, P
AF KUHLBUSCH, TA
   LOBERT, JM
   CRUTZEN, PJ
   WARNECK, P
TI MOLECULAR NITROGEN EMISSIONS FROM DENITRIFICATION DURING BIOMASS BURNING
SO NATURE
LA English
DT Article
AB THE burning of biomass (forest vegetation, savannah grass, firewood and agricultural wastes) due to human activities in the tropics is an important source of nitrogen compounds in the atmosphere 1-4. A recent experimental study 5 identified a gap of 35-60% in the nitrogen balance between its content in the fuel and that recovered in the ash and in gaseous emissions of NO(x), NH3, HCN, CH3CN and other nitriles, N2O, higher-molecular-weight organic compounds and in the smoke. It was suggested that the missing compound had to be molecular nitrogen. We have now carried out appropriate experiments and find that molecular nitrogen is indeed the most important nitrogen species emitted from biomass burning, with the largest contribution coming from flaming combustion. The loss of nutrient nitrogen by biomass burning, which is approximately 10-50 Tg N yr-1 or 5-50% of global nitrogen fixation, may be particularly important for tropical ecosystems.
C1 MAX PLANCK INST CHEM, DEPT BIOGEOCHEM, W-6500 MAINZ, GERMANY.
   MAX PLANCK INST CHEM, DEPT ATMOSPHER CHEM, W-6500 MAINZ, GERMANY.
C3 Max Planck Society; Max Planck Society
RP KUHLBUSCH, TA (corresponding author), UNIV MUNSTER, INST ANORGAN CHEM, WILHELM KLEMM STR 8, W-4400 MUNSTER, GERMANY.
NR 7
TC 73
Z9 78
U1 2
U2 31
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAY 9
PY 1991
VL 351
IS 6322
BP 135
EP 137
DI 10.1038/351135a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL035
UT WOS:A1991FL03500045
DA 2026-03-10
ER

PT J
AU ISSARTEL, JP
   KORONAKIS, V
   HUGHES, C
AF ISSARTEL, JP
   KORONAKIS, V
   HUGHES, C
TI ACTIVATION OF ESCHERICHIA-COLI PROHAEMOLYSIN TO THE MATURE TOXIN BY ACYL CARRIER PROTEIN-DEPENDENT FATTY ACYLATION
SO NATURE
LA English
DT Article
ID multidrug resistance; bacterial transport; hemolysin hlya; gene; secretion; binding; receptor
AB HAEMOLYSIN secreted by pathogenic Escherichia coli binds to mammalian cell membranes, disrupting cellular activities and lysing cells by pore-formation. It is synthesized as nontoxic prohaemolysin (proHlyA), which is activated intracellularly by a mechanism dependent on the cosynthesized HlyC. Haemolysin is one of a family of membrane-targeted toxins, including the leukotoxins of Pasteurella and Actinobacillus and the bifunctional adenylate cyclase haemolysin of Bordetella pertussis, which require this protoxin activation 1-5.  HlyC alone cannot activate proHlyA, but requires a cytosolic activating factor 6.  Here we report the cytosolic activating factor is identical to the acyl carrier protein and that activation to mature toxin is achieved by the transfer of a fatty acyl group from acyl carrier protein to proHlyA. Only acyl carrier protein, not acyl-CoA, can promote HlyC-directed proHlyA acylation, but a range of acyl groups are effective.
RP ISSARTEL, JP (corresponding author), UNIV CAMBRIDGE,DEPT PATHOL,TENNIS COURT RD,CAMBRIDGE CB2 1QP,ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 27
TC 274
Z9 304
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 27
PY 1991
VL 351
IS 6329
BP 759
EP 761
DI 10.1038/351759a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FU201
UT WOS:A1991FU20100069
PM 2062368
DA 2026-03-10
ER

PT J
AU LOCKWOOD, GW
   THOMPSON, DT
AF LOCKWOOD, GW
   THOMPSON, DT
TI SOLAR-CYCLE RELATIONSHIP CLOUDED BY NEPTUNE SUSTAINED BRIGHTNESS MAXIMUM
SO NATURE
LA English
DT Article
ID albedo
AB FOR almost two decades, Neptune's brightness varied inversely, at the level of a few per cent, with the solar cycle.  The anticorrelation was so striking that some causal mechanism seemed necessary, and several suggestions were made 1,2.  Two different but plausible ideas involving solar-induced global changes in Neptune's atmosphere were a cyclic darkening ('tanning') of stratospheric aerosols caused by varying ultraviolet radiation 3 and a variation in the rate of ion-induced nucleation of atmospheric aerosols due to the modulation of galactic cosmic-ray flux by solar activity 4.  In 1990, with the current solar cycle near its peak, however, Neptune departed unexpectedly from the previous cyclic behaviour, attaining its greatest brightness since 1972. Further observations will be needed to decide if the present deviation signals a unique atmospheric phenomenon, and to see if the cyclic anticorrelation will be restored.
RP LOCKWOOD, GW (corresponding author), LOWELL OBSERV,1400 W MARS HILL RD,FLAGSTAFF,AZ 86001, USA.
NR 13
TC 27
Z9 27
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 593
EP 594
DI 10.1038/349593a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000052
DA 2026-03-10
ER

PT J
AU MCDONALD, JH
   KREITMAN, M
AF MCDONALD, JH
   KREITMAN, M
TI ADAPTIVE PROTEIN EVOLUTION AT THE ADH LOCUS IN DROSOPHILA
SO NATURE
LA English
DT Article
ID alcohol-dehydrogenase; stranded-dna; melanogaster
AB PROTEINS often differ in amino-acid sequence across species.  This difference has evolved by the accumulation of neutral mutations by random drift, the fixation of adaptive mutations by selection, or a mixture of the two.  Here we propose a simple statistical test of the neutral protein evolution hypothesis based on a comparison of the number of amino-acid replacement substitutions to synonymous substitutions in the coding region of a locus.  If the observed substitutions are neutral, the ratio of replacement to synonymous fixed differences between species should be the same as the ratio of replacement to synonymous polymorphisms within species.  DNA sequence data on the Adh locus (encoding alcohol dehydrogenase, EC 1.1.1.1) in three species in the Drosophila melanogaster species subgroup do not fit this expectation; instead, there are more fixed replacement differences between species than expected.  We suggest that these excess replacement substitutions result from adaptive fixation of selectively advantageous mutations.
RP MCDONALD, JH (corresponding author), PRINCETON UNIV,DEPT ECOL & EVOLUT BIOL,PRINCETON,NJ 08544, USA.
NR 15
TC 2679
Z9 3072
U1 3
U2 293
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 652
EP 654
DI 10.1038/351652a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200066
PM 1904993
DA 2026-03-10
ER

PT J
AU BI, E
   LUTKENHAUS, J
AF BI, E
   LUTKENHAUS, J
TI FTSZ RING STRUCTURE ASSOCIATED WITH DIVISION IN ESCHERICHIA-COLI
SO NATURE
LA English
DT Article
ID cell-division; dna-replication; inhibitor sula; behavior; mutants; protein; septum; shape; locus
AB GENES for cell division have been identified in Escherichia coli by the isolation of conditional lethal mutations that block cell division, but do not affect DNA replication or segregation 1. Of these genes, ftsZ is of great interest as it acts earliest in the division pathway 2,3, is essential 4, its level dictates the frequency of division 5,6, and it is thought to be the target of two cell-division inhibitors 7-9, SulA, produced in response to DNA damage 10, and MinCD, which prevents division at old sites 11. Here we have used immunoelectronmicroscopy to localize the FtsZ protein to the division site. The results suggest that FtsZ self-assembles into a ring structure at the future division site and may function as a cytoskeletal element. The formation of this ring may be the point at which division is regulated.
RP BI, E (corresponding author), UNIV KANSAS,MED CTR,DEPT MICROBIOL MOLEC GENET & IMMUNOL,KANSAS CITY,KS 66103, USA.
NR 23
TC 1222
Z9 1447
U1 1
U2 116
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 161
EP 164
DI 10.1038/354161a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000064
PM 1944597
DA 2026-03-10
ER

PT J
AU MONTIE, EA
   COSMAN, EC
   THOOFT, GW
   VANDERMARK, MB
   BEENAKKER, CWJ
AF MONTIE, EA
   COSMAN, EC
   THOOFT, GW
   VANDERMARK, MB
   BEENAKKER, CWJ
TI OBSERVATION OF THE OPTICAL ANALOG OF QUANTIZED CONDUCTANCE OF A POINT CONTACT
SO NATURE
LA English
DT Article
ID diffraction
AB DIFFRACTION of light by an aperture is a well-known manifestation of the wave nature of light.  The most familiar case is that of an incident plane wave, which is diffracted into a spatial pattern that is sensitive to the properties of the aperture:  the ratio of transmitted power to incident flux (the transmission cross-section-sigma) depends in a complicated way on the aperture area A (refs 1-3).  For diffuse (that is, isotropic rather than plane-wave) illumination, however, the situation is much simpler 4:  in three dimensions, sigma increases with A in a series of steps of equal height lambda-2/2-pi (where lambda is the wavelength of the light), and is thus independent of the detailed aperture shape.  A similar simplification occurs for two-dimensional diffuse illumination of a slit:  the transmission cross-section per unit slit length increases in stepwise fashion as a function of the slit width W, with steps of height lambda/2 occurring whenever W = n-lambda/2 (n = 1, 2, 3,...) - that is, whenever a new mode is enabled in the slit.  Although the optical transmission characteristics of slits have been studied extensively for plane-wave illumination 5-8, we know of no investigation of this predicted staircase dependence for diffuse illumination.  Here we report the observation of such an effect, and suggest that it may play a part in any process of wave propagation through a constriction.
RP MONTIE, EA (corresponding author), PHILIPS RES LABS,POB 80000,5600 JA EINDHOVEN,NETHERLANDS.
NR 12
TC 50
Z9 53
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 594
EP 595
DI 10.1038/350594a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200053
DA 2026-03-10
ER

PT J
AU MOTOKURA, T
   BLOOM, T
   KIM, HG
   JUPPNER, H
   RUDERMAN, JV
   KRONENBERG, HM
   ARNOLD, A
AF MOTOKURA, T
   BLOOM, T
   KIM, HG
   JUPPNER, H
   RUDERMAN, JV
   KRONENBERG, HM
   ARNOLD, A
TI A NOVEL CYCLIN ENCODED BY A BCL1-LINKED CANDIDATE ONCOGENE
SO NATURE
LA English
DT Article
ID cell-cycle; saccharomyces-cerevisiae; molecular-cloning; messenger-rna; gene; amplification; division; kinetics; meiosis; bcl-1
AB WE have previously identified a candidate oncogene (PRAD1 or D11S287E) on chromosome 11q13 which is clonally rearranged with the parathyroid hormone locus in a subset of benign parathyroid tumours 1,2.  We now report that a cloned human placental PRAD1 complementary DNA encodes a protein of 295 amino acids with sequence similarities to the cyclins. Cyclins can form a complex with and activate p34 cdc2 protein kinase, thereby regulating progress through the cell cycle (reviewed in refs 3-5).  PRAD1 messenger RNA levels vary dramatically across the cell cycle in HeLa cells.  Addition of the PRAD1 protein to interphase clam embryo lysates containing inactive p34cdc2 kinase and lacking endogenous cyclins allows it to be isolated using beads bearing p13suc1, a yeast protein that binds cdc2 and related kinases with high affinity and coprecipitates kinase-associated proteins.  Addition of PRAD1 also induces phosphorylation of histone H1,  a preferred substrate of cdc2. These data suggest that PRAD1 encodes a novel cyclin whose overexpression may play an important part in the development of various tumours with abnormalities in 11q13.
C1 HARVARD UNIV,MASSACHUSETTS GEN HOSP,SCH MED,ENDOCRINE UNIT,BOSTON,MA 02114.
   HARVARD UNIV,SCH MED,DEPT ANAT & CELLULAR BIOL,BOSTON,MA 02115.
C3 Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Massachusetts General Hospital; Harvard University; Harvard Medical School
NR 33
TC 1297
Z9 1412
U1 0
U2 14
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 512
EP 515
DI 10.1038/350512a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300055
PM 1826542
DA 2026-03-10
ER

PT J
AU DOAKE, CSM
   VAUGHAN, DG
AF DOAKE, CSM
   VAUGHAN, DG
TI RAPID DISINTEGRATION OF THE WORDIE ICE SHELF IN RESPONSE TO ATMOSPHERIC WARMING
SO NATURE
LA English
DT Article
ID sheet; fracture
AB THE breaking up of ice shelves around the Antarctic Peninsula has been cited 1 as a "sign that a dangerous warming is beginning in Antarctica".  Here we present satellite images showing the disintegration of the Wordie Ice Shelf, which lies off the west coast of the Antarctic Peninsula (Fig. 1).  Fracture, either in the form of surface crevasses or rifts extending to the bottom of the ice shelf, has been responsible for iceberg calving and weakening the central region of the ice shelf.  These fracture processes, which led to retreat of the ice front, were apparently enhanced by the presence of increased amounts of melt water, resulting from a warming trend recorded in mean annual air temperatures in Marguerite Bay.  If this warming trend continues, other nearby ice shelves on the Antarctic Peninsula may be at risk.  But substantial additional warming would be required before similar processes could initiate breakup of the Ross and Filchner-Ronne ice shelves, which help stabilize the West Antarctic ice sheet.
RP DOAKE, CSM (corresponding author), BRITISH ANTARCTIC SURVEY,MADINGLEY RD,CAMBRIDGE CB3 0ET,ENGLAND.
NR 20
TC 199
Z9 212
U1 0
U2 28
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 328
EP 330
DI 10.1038/350328a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800087
DA 2026-03-10
ER

PT J
AU YU, XM
   HALL, ZW
AF YU, XM
   HALL, ZW
TI EXTRACELLULAR DOMAINS MEDIATING EPSILON SUBUNIT INTERACTIONS OF MUSCLE ACETYLCHOLINE-RECEPTOR
SO NATURE
LA English
DT Article
ID endoplasmic-reticulum; ion channels; transmembrane; mutagenesis; binding; cells
AB LIGAND-gated ion channels, a major class of cell-surface proteins, have a pseudosymmetric structure with five highly homologous subunits arranged around a central ion pore 1. The correct assembly of each channel, whose subunit composition varies with cell type and stage of development, requires specific recognition between the subunits 2-4. Assembly of the pentameric form of the acetylcholine receptor from adult muscle (AChR; alpha-2-beta-epsilon-delta) proceeds by a stepwise pathway starting with the formation of the heterodimers, alpha-epsilon and alpha-delta. The heterodimers then associate with the beta-subunit and with each other to form the complete receptor 5-7,21. We have now determined which parts of the subunits mediate the interactions during assembly of the adult form of the receptor from mouse muscle by using a chimaeric subunit in which the N-terminal and C-terminal extracellular domains are derived from the E subunit with the remainder from the beta-subunit. The epsilon and beta-subunits were chosen because the epsilon-subunit forms a heterodimer with the alpha-subunit in the pathway for assembly of the receptor, whereas the beta-subunit does not. The epsilon-beta chimaera can substitute for the epsilon but not the beta-subunit in the oligomeric receptor, indicating that the alpha-subunit specifically recognizes an extracellular domain of the epsilon-subunit.
C1 UNIV CALIF SAN FRANCISCO,SCH MED,DEPT PHYSIOL,SAN FRANCISCO,CA 94143.
C3 University of California System; University of California San Francisco
NR 21
TC 80
Z9 86
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 64
EP 67
DI 10.1038/352064a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800071
PM 1712080
DA 2026-03-10
ER

PT J
AU KOYAMA, K
   TAKANO, S
   TAWARA, Y
AF KOYAMA, K
   TAKANO, S
   TAWARA, Y
TI IRON DISTRIBUTION IN THE INTRACLUSTER GAS OF THE VIRGO CLUSTER OF GALAXIES
SO NATURE
LA English
DT Article
ID x-ray-emission; radiation
AB DIFFUSE X-ray emission, particularly fluorescence from the iron K line, from hot gas in the clusters of galaxies provides valuable information on the structure and evolution of the clusters 1.  Because heavy elements such as iron are made in stars, the presence of iron distinguishes gas that originated in galaxies from primordial gas that has remained unprocessed since formation of the cluster.  Previous observations of about 20 clusters indicate that iron abundance in the hot gas is about half the cosmic value 2, but these observations were made with non-imaging devices which gave no information on the spatial distribution of the iron.  Lack of spatial distribution can also skew the estimated mean iron abundance determined in this way.  Here we report evidence of an iron abundance gradient in hot gas in the Virgo cluster of galaxies.  Iron is centrally concentrated, indicating that gas at the cluster core has been enriched by galactic mass loss.
RP KOYAMA, K (corresponding author), NAGOYA UNIV,SCH SCI,DEPT ASTROPHYS,CHIKUSA KU,NAGOYA 46401,JAPAN.
NR 13
TC 51
Z9 51
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 135
EP 136
DI 10.1038/350135a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500049
DA 2026-03-10
ER

PT J
AU DAVEY, RJ
   BLACK, SN
   BROMLEY, LA
   COTTIER, D
   DOBBS, B
   ROUT, JE
AF DAVEY, RJ
   BLACK, SN
   BROMLEY, LA
   COTTIER, D
   DOBBS, B
   ROUT, JE
TI MOLECULAR DESIGN BASED ON RECOGNITION AT INORGANIC SURFACES
SO NATURE
LA English
DT Article
AB MOLECULAR recognition at inorganic surfaces has the potential to provide control over crystal growth processes.  For organic surfaces, molecules that influence crystallization 1-3 can be derived by rational modification of host molecules to give the stereochemistry required by the surface structure.  This approach is of little use for inorganic systems, however, because the relatively simple stereochemistries of the surfaces and ions concerned allow little scope for similar manipulation.  Previous work 4-6, therefore, has been essentially phenomenological.  Here we show that a detailed understanding of recognition processes at inorganic surfaces can nevertheless lead to the rational design of surface-active molecules.  We have used crystal morphological characteristics to deduce the nature of the surface binding sites of diphosphonates on barium sulphate crystals, and have thereby been able to design new surface-active molecules with improved efficacy.
RP DAVEY, RJ (corresponding author), ICI CHEM & POLYMERS LTD,DEPT RES & TECHNOL,HEATH,RUNCORN WA7 4QD,CHESHIRE,ENGLAND.
NR 10
TC 136
Z9 143
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 10
PY 1991
VL 353
IS 6344
BP 549
EP 550
DI 10.1038/353549a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GJ643
UT WOS:A1991GJ64300063
DA 2026-03-10
ER

PT J
AU ANDERSON, C
   COLES, P
   EWING, T
AF ANDERSON, C
   COLES, P
   EWING, T
TI EXPLORING THE STILL UNEXPLORED
SO NATURE
LA English
DT Article
NR 0
TC 1
Z9 1
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 287
EP 288
DI 
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800046
DA 2026-03-10
ER

PT J
AU WHITE, GJ
   PADMAN, R
AF WHITE, GJ
   PADMAN, R
TI IMAGES OF ATOMIC CARBON IN THE INTERSTELLAR-MEDIUM
SO NATURE
LA English
DT Article
ID molecular cloud; photodissociation regions; orion nebula; m17 sw; co; submillimeter; features; emission; omc-1; model
AB ALTHOUGH carbon is the fourth most cosmically abundant element, it exists only rarely as neutral atoms, because carbon that is cool enough to be neutral rapidly combines with other atoms to form molecules such as CO. Atomic carbon (C I) forms when CO is dissociated by ultraviolet photons, but the dissociation energy is close to the ionization energy of C I, so that neutral carbon is easily ionized into C II. At the edges of molecular clouds, carbon will exist mostly in the form of C II, with only a narrow transition zone containing C I covering the interior of the cloud, where CO predominates.   We present here observations of the submillimetre line due to the P-3(1) --> P-3(0) fine-structure transition of C I, from which we construct high-resolution maps of neutral carbon in molecular clouds in the star-forming region Orion A, in the externally illuminated cloud S140, in the edge-on ionization front of M17, and at the Galactic Centre. C I emission is indeed concentrated in a transition zone, but we confirm earlier suggestions that neutral carbon is also present at lower concentrations within the clouds. In the case of M17, our images provide direct evidence for clumpiness in the cloud distribution.
C1 UNIV CAMBRIDGE,CAVENDISH LAB,MULLARD RADIO ASTRON OBSERV,CAMBRIDGE CB3 0HE,ENGLAND.
C3 University of Cambridge
RP WHITE, GJ (corresponding author), UNIV LONDON,QUEEN MARY & WESTFIELD COLL,DEPT PHYS,MILE END RD,LONDON E1 4NS,ENGLAND.
NR 20
TC 69
Z9 72
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 511
EP 513
DI 10.1038/354511a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100009
DA 2026-03-10
ER

PT J
AU IRIFUNE, T
   FUJINO, K
   OHTANI, E
AF IRIFUNE, T
   FUJINO, K
   OHTANI, E
TI A NEW HIGH-PRESSURE FORM OF MGAL2O4
SO NATURE
LA English
DT Article
ID phase; calcium; mantle
AB MAGNESIUM aluminium spinel (MgAl2O4) is a common constituent of low-pressure peridotite xenoliths, and is an important host mineral for aluminium and other trivalent cations in the shallow upper mantle. Shock-wave compression data for MgAl2O4 demonstrated 1 that spinel would transform to denser phases at pressures greater than 40 GPa, although there was much uncertainty in the pressure estimation.  Later, spinel was found to transform under static compression to the denser oxide mixture (MgO periclase + Al2O3 corundum 2,3) at pressures above 15 GPa (ref. 4).  Detailed analyses of the shock-compression data, however, suggested the presence of a still denser phase of MgAl2O4 spinel at much higher pressures 5,6.  Here we report the transformation of MgAl2O4 spinel to a new high-pressure form at pressures above 25 GPa in a multi-anvil high-pressure apparatus.  The new MgAl2O4 phase has a structure similar to that of CaFe2O4 (calcium ferrite) and its zero-pressure density is 3.937(3) g cm-3, which is approximately 2% denser than the lower-pressure assemblage of periclase + corundum.  We suggest that this high-pressure form of MgAl2O4 may be an important host of aluminium in the Earth's lower mantle.
C1 TOHOKU UNIV,FAC SCI,INST MINERAL PETROL & ECON GEOL,SENDAI,MIYAGI 980,JAPAN.
C3 Tohoku University
RP IRIFUNE, T (corresponding author), EHIME UNIV,FAC SCI,DEPT EARTH SCI,MATSUYAMA,EHIME 790,JAPAN.
NR 17
TC 207
Z9 218
U1 0
U2 60
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 409
EP 411
DI 10.1038/349409a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400048
DA 2026-03-10
ER

PT J
AU BERNARD, A
   DEMAIFFE, D
   MATTIELLI, N
   PUNONGBAYAN, RS
AF BERNARD, A
   DEMAIFFE, D
   MATTIELLI, N
   PUNONGBAYAN, RS
TI ANHYDRITE-BEARING PUMICES FROM MOUNT-PINATUBO - FURTHER EVIDENCE FOR THE EXISTENCE OF SULFUR-RICH SILICIC MAGMAS
SO NATURE
LA English
DT Article
ID el-chichon volcano; 1982 eruptions; sulfur; cloud
AB THE eruption of El Chichon in 1982 showed that relatively small but sulphur-rich eruptions from calc-alkaline volcanoes can produce long-lived stratospheric clouds of sulphate aerosols 1,2, which affect the global climate 3,4. Here we report the presence of primary anhydrite (CaSO4) phenocrysts in dacitic pumice clasts from the 14-15 June eruption of Mount Pinatubo, which clearly shows that the Mount Pinatubo magma is also rich in sulphur. The post-eruptive sulphur content of the Pinatubo pumices ranges from 0.37 to 0.48 wt% SO3. The considerable amount of sulphate aerosol injected into the stratosphere by the Mount Pinatubo eruptions 5 should lead to a measurable cooling of the Earth's surface over the next few years, and could also trigger heterogeneous chemical reactions leading to stratospheric ozone depletion 6. This new eruption of a sulphur-rich silicic magma thus shows that the El Chichon eruption is not unique, and that climate-modifying eruptions of this type may be more common than previously believed.
C1 PHILIPPINE INST VOLCANOL & SEISMOL,QUEZON CITY,PHILIPPINES.
RP BERNARD, A (corresponding author), UNIV LIBRE BRUXELLES,DEPT GEOL,CP 160,50 AVE FD ROOSEVELT,B-1050 BRUSSELS,BELGIUM.
NR 19
TC 86
Z9 91
U1 0
U2 11
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 139
EP 140
DI 10.1038/354139a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000056
DA 2026-03-10
ER

PT J
AU SUSLICK, KS
   CHOE, SB
   CICHOWLAS, AA
   GRINSTAFF, MW
AF SUSLICK, KS
   CHOE, SB
   CICHOWLAS, AA
   GRINSTAFF, MW
TI SONOCHEMICAL SYNTHESIS OF AMORPHOUS IRON
SO NATURE
LA English
DT Article
ID sonoluminescence; liquids
AB AMORPHOUS metallic alloys ('metallic glasses') lack long-range crystalline order and have unique electronic, magnetic and corrosion-resistant properties 1-3.  Their applications include use in power-transformer cores, magnetic storage media, cryothermometry and corrosion-resistant coatings.  The production of metallic glasses is made difficult, however, by the extremely rapid cooling from the melt that is necessary to prevent crystallization.  Cooling rates of about 10(5) to 10(7) K s-1 are generally required; for comparison, plunging red-hot steel into water produces cooling rates of only about 2,500 K s-1.  Metallic glasses can be formed by splattering molten metal on a cold surface using techniques such as gun, roller or splat quenching 4,5.  Acoustic cavitation is known to induce extreme local heating in otherwise cold liquids, and to provide very rapid cooling rates 6-11.  Here we describe the synthesis of metallic-glass powders using the microscopically extreme (yet macroscopically mild) conditions induced by high-intensity ultrasound.  The sonolysis of iron pentacarbonyl, a volatile organometallic compound, produces nearly pure amorphous iron.  This amorphous iron powder is a highly active catalyst for the Fischer-Tropsch hydrogenation of carbon monoxide and for hydrogenolysis and dehydrogenation of saturated hydrocarbons.
C1 KEI MGUNG UNIV,COLL ENGN,TAEGU,SOUTH KOREA.
   POLISH ACAD SCI,INST ORGAN CHEM,WARSAW 42,POLAND.
C3 Keimyung University; Polish Academy of Sciences; Institute of Organic Chemistry of the Polish Academy of Sciences
RP SUSLICK, KS (corresponding author), UNIV ILLINOIS,SCH CHEM SCI,505 S MATHEWS AVE,URBANA,IL 61801, USA.
NR 27
TC 1153
Z9 1260
U1 2
U2 374
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 414
EP 416
DI 10.1038/353414a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600051
DA 2026-03-10
ER

PT J
AU STEPHENSON, JAE
   SCOURFIELD, MWJ
AF STEPHENSON, JAE
   SCOURFIELD, MWJ
TI IMPORTANCE OF ENERGETIC SOLAR PROTONS IN OZONE DEPLETION
SO NATURE
LA English
DT Article
ID stratospheric ozone; nitric-oxide; events
AB CHLORINE-catalysed depletion of the stratospheric ozone layer has commanded considerable attention since 1985, when Farman et al. 1 observed a decrease of 50% in the total column ozone over Antarctica in the austral spring.  Here we examine the depletion of stratospheric ozone caused by the reaction of ozone with nitric oxide generated by energetic solar protons, associated with solar flares.  During large solar flares in March 1989, satellite observations indicated that total column ozone was depleted by approximately 9% over approximately 20% of the total area between the South Pole and latitude 70-degrees-S.  Chlorine-catalysed ozone depletion takes place over a much larger area, but our results indicate that the influence of solar protons on atmospheric ozone concentrations should not be ignored.
RP STEPHENSON, JAE (corresponding author), UNIV NATAL,SPACE PHYS RES INST,DURBAN 4001,SOUTH AFRICA.
NR 9
TC 15
Z9 15
U1 1
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 137
EP 139
DI 10.1038/352137a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700048
DA 2026-03-10
ER

PT J
AU POULSEN, HF
   ANDERSEN, NH
   ANDERSEN, JV
   BOHR, H
   MOURITSEN, OG
AF POULSEN, HF
   ANDERSEN, NH
   ANDERSEN, JV
   BOHR, H
   MOURITSEN, OG
TI RELATION BETWEEN SUPERCONDUCTING TRANSITION-TEMPERATURE AND OXYGEN ORDERING IN YBA2CU3O6+X
SO NATURE
LA English
DT Article
AB THE superconducting transition temperature, T(c), of the ceramic high-temperature superconductor YBa2Cu3O6+x is known to depend not only on the oxygen stoichiometry x (0 < x < 1) but also on the specific ordering of the oxygen atoms in the basal CuO planes 1-7.  Here we present computer simulations of the formation of oxygen-ordered domains of orthorhombic structure in the basal CuO plane using a microscopic model of the oxygen ordering.  Together with a minimal-model assumption for the charge transfer, our calculations strongly suggest that it is these domains that are responsible for the characteristic variation of T(c)(x).  Our results lead to a theoretical prediction of T(c)(x) that is in close quantitative agreement with experiments.
C1 RISO NATL LAB,DEPT PHYS,DK-4000 ROSKILDE,DENMARK.
   TECH UNIV DENMARK,DEPT STRUCT PROPERTIES MAT,DK-2800 LYNGBY,DENMARK.
   TECH UNIV DENMARK,DEPT PHYS CHEM,DK-2800 LYNGBY,DENMARK.
C3 Technical University of Denmark; Technical University of Denmark; Technical University of Denmark
NR 15
TC 178
Z9 183
U1 1
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 594
EP 596
DI 
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000053
DA 2026-03-10
ER

PT J
AU VANDERWATT, HV
   BARNARD, RO
   CRONJE, IJ
   DEKKER, J
   CROFT, GJB
   VANDERWALT, MM
AF VANDERWATT, HV
   BARNARD, RO
   CRONJE, IJ
   DEKKER, J
   CROFT, GJB
   VANDERWALT, MM
TI AMELIORATION OF SUBSOIL ACIDITY BY APPLICATION OF A COAL-DERIVED CALCIUM FULVATE TO THE SOIL SURFACE
SO NATURE
LA English
DT Article
ID gypsum
AB SUBSOIL acidity is a serious problem in many tropical and subtropical soils 1-3.  The high acidity, low calcium contents and often toxic levels of soluble and/or exchangeable aluminum severely impair plant-root development in these soils 1-3.  The relative immobility of surface-applied liming materials limits their ability to reduce subsoil acidity.  Recently, the use of gypsum or phosphogypsum has been advocated as an alternative to lime 3-7.  On the other hand, it is well known that humic substances can mobilize and form complexes with metals in soils 8-11.  Here we report that a newly available, coal-derived calcium-fulvate is highly efficient as a carrier of calcium in the soil profile.   Moreover, subsoil pH was considerably higher when calcium-fulvate was applied to the soil surface, than when gypsum, calcium-EDTA, Ca(OH)2 or CaCO3 were applied.
C1 CSIR,DIV ENERGY TECHNOL,PRETORIA 0001,SOUTH AFRICA.
C3 Council for Scientific & Industrial Research (CSIR) - South Africa
RP VANDERWATT, HV (corresponding author), UNIV PRETORIA,DEPT SOIL SCI & PLANT NUTR,PRETORIA 0002,SOUTH AFRICA.
NR 13
TC 31
Z9 35
U1 0
U2 18
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 146
EP 148
DI 10.1038/350146a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500055
DA 2026-03-10
ER

PT J
AU ATWOOD, JL
   HAMADA, F
   ROBINSON, KD
   ORR, GW
   VINCENT, RL
AF ATWOOD, JL
   HAMADA, F
   ROBINSON, KD
   ORR, GW
   VINCENT, RL
TI X-RAY-DIFFRACTION EVIDENCE FOR AROMATIC PI HYDROGEN-BONDING TO WATER
SO NATURE
LA English
DT Article
ID chloride complex; benzene
AB THE interaction of water with aromatic moieties is of importance in biological systems, as most encounter an aqueous environment during their normal functions.  For example, common constituents of globular proteins such as phenylalanine, tryptophan and tyrosine possess aromatic side-chains 1 that may encounter water molecules inside the protein structure 2.  As a model for hydrogen-bonding interactions with aromatics, we have performed X-ray diffraction studies on crystalline Na4[calix[4]arene sulphonate].13.5H20.  Calixarene molecules 3,4 contain hydrophobic cavities comprised of aromatic groups, rimmed, in the case of the water-soluble sulphonates (R = -SO3Na), by hydrophilic groups 5,6.  In the absence of a hydrophobic guest, the cavity invariably contains a water molecule.  The low-temperature X-ray crystal structure of this compound (see Table 1 and Fig. 1) shows direct evidence for hydrogen bonding between water and the aromatic pi-electrons in the solid state.
RP ATWOOD, JL (corresponding author), UNIV ALABAMA,DEPT CHEM,TUSCALOOSA,AL 35487, USA.
NR 16
TC 377
Z9 387
U1 0
U2 42
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 683
EP 684
DI 10.1038/349683a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700042
DA 2026-03-10
ER

PT J
AU KERKAM, K
   VINEY, C
   KAPLAN, D
   LOMBARDI, S
AF KERKAM, K
   VINEY, C
   KAPLAN, D
   LOMBARDI, S
TI LIQUID CRYSTALLINITY OF NATURAL SILK SECRETIONS
SO NATURE
LA English
DT Article
ID physical-property; fibroin; polymers; textures; modulation
AB NATURAL silk exhibits a strength and stiffness similar to, and a toughness up to ten times greater than, that of artificial high-performance fibres 1-5. These exceptional tensile properties, the optical birefringence of some silk secretions 6-9 and the molecular order exhibited by some synthetic polypeptides in solution 10 all suggest that natural silk secretions might form liquid-crystalline phases. We have now used polarized-light microscopy to study the secretions from major ampullae of spiders (Nephila clavipes) and from silk glands of silkworms (Bombyx mori). As the concentration is increased by evaporation of water, nematic liquid-crystalline microstructures develop. We deduce that natural silk secretions become liquid crystalline after leaving the gland but before solidifying into a fibre, thus promoting global molecular alignment in the fibre. Our hand-drawn fibres from droplets of secretion, as well as sheared thin films, show a banded microstructure which is indicative of a periodic variation in the direction of molecular alignment. Both B. mori and N. clavipes, on the other hand, have apparently developed processing routes that ensure uniform molecular alignment: the threads and draglines, respectively, of these species do not show banded microstructures.
C1 UNIV WASHINGTON, DEPT MAT SCI & ENGN FB10, SEATTLE, WA 98195 USA.
   USA, CTR RES DEV & ENGN, NATICK, MA 01760 USA.
C3 University of Washington; University of Washington Seattle; United States Department of Defense; United States Army; U.S. Army Corps of Engineers; U.S. Army Engineer Research & Development Center (ERDC)
NR 30
TC 168
Z9 200
U1 3
U2 108
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 596
EP 598
DI 10.1038/349596a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000054
DA 2026-03-10
ER

PT J
AU ILMAIN, F
   TANAKA, T
   KOKUFUTA, E
AF ILMAIN, F
   TANAKA, T
   KOKUFUTA, E
TI VOLUME TRANSITION IN A GEL DRIVEN BY HYDROGEN-BONDING
SO NATURE
LA English
DT Article
ID complementary polymers; poly(acrylic acid); phase-transitions; complexation; collapse
AB INTERACTIONS between macromolecules fall into four categories:  ionic, hydrophobic, van der Waals and hydrogen bonding.  Phase transitions in polymer gels provide a means of studying these interactions.  Many gels will undergo reversible, discontinuous volume changes in response to changes in, for example, temperature, gel composition or light irradiation 1-5.  These transitions result from the competition between repulsive intermolecular forces, usually electrostatic in nature, that act to expand the polymer network, and an attractive force that acts to shrink it.  Volume transitions in gels have been observed that are driven by all of the above-mentioned forces except hydrogen bonding (ref 6-10; T.T. et al., unpublished data; H. Inomata et al., personal communication).  Here we report on a phase transition in an interpenetrating polymer network of poly(acrylamide) and poly(acrylic acid) that completes this picture - it is controled by cooperative 'zipping' interactions between the molecules which result from hydrogen bonding.  Cooperativity is an essential feature of the interactions, in the independent hydrogen bonds would not provide a sufficient driving force for the transition.  A further novel characteristic of this phase transition is that the swelling (in water) is induced by an increase rather than a decrease in temperature.
C1 UNIV STRASBOURG 1,ULTRASONS & DYNAM FLUIDES COMPLEXES LABS,F-67070 STRASBOURG,FRANCE.
   UNIV TSUKUBA,INST APPL BIOCHEM,TSUKUBA,IBARAKI 305,JAPAN.
   MIT,CTR MAT SCI & ENGN,CAMBRIDGE,MA 02139.
C3 Universites de Strasbourg Etablissements Associes; Universite de Strasbourg; University of Tsukuba; Massachusetts Institute of Technology (MIT)
RP ILMAIN, F (corresponding author), MIT,DEPT PHYS,CAMBRIDGE,MA 02139, USA.
NR 18
TC 458
Z9 506
U1 0
U2 166
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 400
EP 401
DI 10.1038/349400a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400044
DA 2026-03-10
ER

PT J
AU DICKENS, RJ
   CROKE, BFW
   CANNON, RD
   BELL, RA
AF DICKENS, RJ
   CROKE, BFW
   CANNON, RD
   BELL, RA
TI EVIDENCE FROM STELLAR ABUNDANCES FOR A LARGE AGE DIFFERENCE BETWEEN 2 GLOBULAR-CLUSTERS
SO NATURE
LA English
DT Article
ID galactic halo; ngc-288; photometry; ngc-362; ngc-6397; stars
AB THE globular clusters NGC288 and NGC362 are central to recent claims 1-4 of large age differences (approximately 3 Gyr) between globular clusters associated with our Galaxy.  According to standard models for the formation of the Galaxy 5, the system of globular clusters formed during the dynamical collapse of the protogalactic cloud, a process which should have lasted no more than 1 Gyr 6.  But the claimed age differences are derived from stellar evolution models using assumed CNO abundances, and uncertainty in the actual CNO abundances of about a factor of three could account for an apparent 2-Gyr age difference 7,8.  We have accurately measured abundances in red giants in NGC288 and NGC362, and find that the Fe abundance and the sum of the C, N and O abundances are essentially the same in every star studied.  By eliminating compositional differences and thus confirming the reality of the age difference, these results imply a cluster formation period that is hard to reconcile with the standard collapse model 5,6.
C1 UNIV NEW S WALES,KENSINGTON,NSW 2033,AUSTRALIA.
   ANGLO AUSTRALIAN OBSERV,EPPING,NSW 2121,AUSTRALIA.
   UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742.
C3 University of New South Wales Sydney; University System of Maryland; University of Maryland College Park
RP DICKENS, RJ (corresponding author), RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND.
NR 23
TC 81
Z9 82
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 16
PY 1991
VL 351
IS 6323
BP 212
EP 214
DI 10.1038/351212a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FL990
UT WOS:A1991FL99000048
DA 2026-03-10
ER

PT J
AU FRAIL, DA
   KULKARNI, SR
AF FRAIL, DA
   KULKARNI, SR
TI UNUSUAL INTERACTION OF THE HIGH-VELOCITY PULSAR PSR1757-24 WITH THE SUPERNOVA REMNANT G5.4-1.2
SO NATURE
LA English
DT Article
ID radio-sources; origin; fields
AB THE peculiar fan-shaped morphology of the galactic radio source G5.4-1.2 has prompted much speculation about its nature 1-4.  Here we report high-resolution observations obtained with the Very Large Array, which reveal a compact, highly polarized, flat-spectrum radio nebula on the western edge of G5.4-1.2.  We also confirm the presence of a 125-ms pulsar 5, PSR1757-24, associated with the radio source, and find that it is located near the centre of the newly discovered nebula.  We argue that the pulsar is associated with G5.4-1.2, which we identify as a supernova remnant, and that it was born with a high enough velocity, approximately 2,000 km s-1, for it to overtake the decelerating supernova shell, creating the peripheral radio nebula.  The fortuitous near-coincidence of the pulsar velocity with the shell velocity accounts for the unusual overall shape of the remnant.  If the large velocity of the pulsar is confirmed by future observation of its proper motion, the possibility of asymmetric supernova explosions must be taken seriously, and other previously unsuspected associations between pulsars and supernova remnants may emerge.
C1 CALTECH,DIV PHYS MATH & ASTRON 10524,PASADENA,CA 91125.
   UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106.
C3 California Institute of Technology; University of California System; University of California Santa Barbara
RP FRAIL, DA (corresponding author), NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801, USA.
NR 16
TC 115
Z9 115
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 785
EP 787
DI 10.1038/352785a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400052
DA 2026-03-10
ER

PT J
AU WOODWARD, RL
   MASTERS, G
AF WOODWARD, RL
   MASTERS, G
TI LOWER-MANTLE STRUCTURE FROM SCS-S DIFFERENTIAL TRAVEL-TIMES
SO NATURE
LA English
DT Article
ID 3-dimensional structure; earths interior; velocity; heterogeneity; boundary; core; inversion
AB KNOWLEDGE of the spectrum of structure in the lower mantle is crucial to our understanding of the dynamical evolution of the Earth and, in principle, can be inferred from the analysis of global seismic data sets. The long-wavelength compressional velocity structure has usually been constrained through tomographic inversion of the ISC catalogue of P-wave travel times 1-3, whereas shear velocity has been inferred from waveform modelling of long-period shear waves 4-6. The models that have been produced are similar in only the largest-scale features 7 and explain little of the variance of the raw data used in their construction. Thus, there is a legitimate concern that the current generation of global-scale models give only a crude approximation to the largest-scale structure and that there may be significant aliasing of short-wavelength heterogeneity. Here we use ScS - S differential travel times to demonstrate that the three-dimensional structure of the lower mantle is indeed dominated by continental-scale features. Particularly convincing is the fact that the features are apparent in the raw data and are not the product of a complicated modelling procedure
C1 UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,INST GEOPHYS & PLANETARY PHYS,LA JOLLA,CA 92093.
C3 University of California System; University of California San Diego; Scripps Institution of Oceanography
NR 29
TC 82
Z9 83
U1 1
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 231
EP 233
DI 10.1038/352231a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500062
DA 2026-03-10
ER

PT J
AU LIN, DNC
   WOOSLEY, SE
   BODENHEIMER, PH
AF LIN, DNC
   WOOSLEY, SE
   BODENHEIMER, PH
TI FORMATION OF A PLANET ORBITING PULSAR 1829-10 FROM THE DEBRIS OF A SUPERNOVA EXPLOSION
SO NATURE
LA English
DT Article
ID x-ray sources; neutron stars; accretion; evolution; planetesimals; clouds
AB THE 10-Earth-mass planet 1 in a nearly circular 0.7-AU orbit around PSR1829 - 10 is unlikely to have survived the supernova, or especially the pre-supernova evolution of the star that became the pulsar. Here we describe how the planet might have been created inside the young supernova remnant 1-3. The principal difficulty lies not in providing enough mass or conducive thermodynamic conditions for planet formation, but in explaining the large angular momentum (approximately 3 x 10(48) erg s) and small eccentricity (< 0.1) of the orbit. We propose that the planet formed from a rotationally supported disk of approximately 0.02 solar mass of heavy elements that fell back from the supernova explosion to an initial radius of about 1,000 km. Viscous evolution of the disk then concentrated most of its angular momentum into a small amount of material at the disk's outer extremity: 10 Earth masses at 10(13) cm. Here, dust grains that had condensed and precipitated towards the midplane grew through cohesive collisions and gravitational instabilities into 100-km planetesimals, which coagulated into the planet on a million-year timescale. We find the presence of a second planet, more massive and more distant, unlikely, although residual planetesimals may provide the fuel for gamma-ray bursts.
RP LIN, DNC (corresponding author), UNIV CALIF SANTA CRUZ OBSERV, LICK OBSERV, BOARD STUDIES ASTRON & ASTROPHYS, SANTA CRUZ, CA 95064 USA.
NR 47
TC 81
Z9 84
U1 0
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 31
PY 1991
VL 353
IS 6347
BP 827
EP 829
DI 10.1038/353827a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GM732
UT WOS:A1991GM73200052
DA 2026-03-10
ER

PT J
AU MARAN, SP
   MICHALITSIANOS, AG
   OLIVERSEN, RJ
   SONNEBORN, G
AF MARAN, SP
   MICHALITSIANOS, AG
   OLIVERSEN, RJ
   SONNEBORN, G
TI SPECTRAL TRANSFORMATION OF THE UNUSUAL VARIABLE-STAR MWC560 TO RESEMBLE A NOVA
SO NATURE
LA English
DT Article
AB MWC560 is an emission-line star catalogued 1 in 1943 and later described 2 as an 'extraordinary symbiotic-like variable'.  It was recently found 3 to be undergoing a photometric and spectroscopic outburst.  A dramatic change has occurred in the ultraviolet spectrum of MWC560, so that it now closely resembles the spectrum of a nova shortly after outburst.  This event, detected by the International Ultraviolet Explorer satellite, may signal a major mass-ejection episode such as presumably occurred in past centuries in the symbiotic star R Aquarii to produce the well-known bipolar nebula, and it may herald the emergence of a standard symbiotic-star emission-line spectrum in MWC560, corresponding to a change in evolutionary state.
RP MARAN, SP (corresponding author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA.
NR 13
TC 14
Z9 16
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 404
EP 406
DI 10.1038/350404a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200042
DA 2026-03-10
ER

PT J
AU MALINVERNO, A
AF MALINVERNO, A
TI INVERSE SQUARE-ROOT DEPENDENCE OF MID-OCEAN-RIDGE FLANK ROUGHNESS ON SPREADING RATE
SO NATURE
LA English
DT Article
ID accreting plate boundary; topography; seafloor
AB THE topographic roughness of mid-ocean-ridge flanks is known to increase with decreasing spreading rate 1-4, but the exact form of this relationship has not been established. As the topographic features that make up ridge flank roughness (abyssal hills) are created near the axes of mid-ocean ridges by faulting and volcanism 5-7, the relationship between roughness and spreading rate may shed light on the process of crustal accretion at spreading centres. Here I present measurements of ridge flank roughness on profiles crossing the world mid-ocean-ridge system, which show that roughness is proportional to the inverse square-root of the spreading rate. This result is consistent with some very simple inferences of how the topographic roughness of mid-ocean-ridge flanks scales with the lithospheric thickness near ridge axes, as determined by thermal models.
RP MALINVERNO, A (corresponding author), COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964, USA.
NR 28
TC 87
Z9 94
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 58
EP 60
DI 10.1038/352058a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800068
DA 2026-03-10
ER

PT J
AU JULIER, C
   HYER, RN
   DAVIES, J
   MERLIN, F
   SOULARUE, P
   BRIANT, L
   CATHELINEAU, G
   DESCHAMPS, I
   ROTTER, JI
   FROGUEL, P
   BOITARD, C
   BELL, JI
   LATHROP, GM
AF JULIER, C
   HYER, RN
   DAVIES, J
   MERLIN, F
   SOULARUE, P
   BRIANT, L
   CATHELINEAU, G
   DESCHAMPS, I
   ROTTER, JI
   FROGUEL, P
   BOITARD, C
   BELL, JI
   LATHROP, GM
TI INSULIN-IGF2 REGION ON CHROMOSOME-11P ENCODES A GENE IMPLICATED IN HLA-DR4-DEPENDENT DIABETES SUSCEPTIBILITY
SO NATURE
LA English
DT Article
ID wiedemann-beckwith syndrome; mellitus; dna; sequence; locus; iddm; inheritance; linkage; hla
AB A CLASS of alleles at the VNTR (variable number of tandem repeat) locus in the 5' region of the insulin gene (INS) on chromosome 11p is associated with increased risk of insulin-dependent diabetes mellitus (IDDM) 1-6, but family studies have failed to demonstrate linkage 5,7. INS is thought to contribute to IDDM susceptibility but this view has been difficult to reconcile with the lack of linkage evidence 6-8. We thus investigated polymorphisms of INS and neighbouring loci in random diabetics, IDDM multiplex families and controls. HLA-DR4-positive diabetics showed an increased risk associated with common variants at polymorphic sites in a 19-kilobase segment spanned by the 5' INS VNTR and the third intron of the gene for insulin-like growth factor II (IGF2). As INS is the major candidate gene from this region, diabetic and control sequences were compared to identify all INS polymorphisms that could contribute to disease susceptibility. In multiplex families the IDDM-associated alleles were transmitted preferentially to HLA-DR4-positive diabetic offspring from heterozygous parents. The effect was strongest in paternal meioses, suggesting a possible role for maternal imprinting. Our results strongly support the existence of a gene or genes affecting HLA-DR4 IDDM susceptibility which is located in a 19-kilobase region of INS-IGF2. Our results also suggest new ways to map susceptibility loci in other common diseases.
C1 JOHN RADCLIFFE HOSP,INST MOLEC MED,MOLEC IMMUNOL GRP,OXFORD OX3 9DU,ENGLAND.
   CTR ETUD POLYMORHISME HUMAIN,F-75010 PARIS,FRANCE.
   HOP ST LOUIS,SERV ENDOCRINOL,F-75010 PARIS,FRANCE.
   HOP NECKER ENFANTS MALAD,INSERM,U25,F-75730 PARIS 15,FRANCE.
   CEDARS SINAI MED CTR,DIV MED GENET,LOS ANGELES,CA 90048.
   UNIV CALIF LOS ANGELES,SCH MED,LOS ANGELES,CA 90024.
C3 University of Oxford; Universite Paris Cite; Assistance Publique Hopitaux Paris (APHP); Hopital Universitaire Saint-Louis - APHP; Assistance Publique Hopitaux Paris (APHP); Universite Paris Cite; Hopital Universitaire Necker-Enfants Malades - APHP; Institut National de la Sante et de la Recherche Medicale (Inserm); Cedars Sinai Medical Center; University of California System; University of California Los Angeles; University of California Los Angeles Medical Center; David Geffen School of Medicine at UCLA
FU Wellcome Trust Funding Source: Medline
NR 32
TC 375
Z9 395
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 155
EP 159
DI 10.1038/354155a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000062
PM 1944595
DA 2026-03-10
ER

PT J
AU FARQUHAR, J
   CHACKO, T
AF FARQUHAR, J
   CHACKO, T
TI ISOTOPIC EVIDENCE FOR INVOLVEMENT OF CO2-BEARING MAGMAS IN GRANULITE FORMATION
SO NATURE
LA English
DT Article
ID charnockite formation; southern india; sri-lanka; metamorphic rocks; graphite; kerala; pressure; calcite; origin
AB IT has been suggested 1,2 that CO2-bearing magmas play an important part in the formation of granulites. These magmas crystallize directly into granulites, and also expel fluids which promote the development of granulite-facies mineral assemblages in adjacent country rocks. Direct evidence for carbonic fluids remains elusive, however, as granulite-facies aureoles adjacent to charnockitic intrusives 1 may result either from the influx of carbonic fluids derived from the intrusives or simply from extraction of water into a vapour-absent melt. Here we report results of a detailed study of carbon isotope compositions of graphite associated with a charnockite dyke from the Ponmudi quarry of south India. Higher graphite abundances and an anomalously heavy carbon isotopic Composition (delta-C-13gr = -8.1 parts per thousand) at the dyke margins indicate that externally derived CO2-rich fluids were transported into the Ponmudi paragneisses by the intrusive, and precipitated nearly quantitatively as graphite on encountering reducing country rocks. The occurrence of large orthopyroxene crystals along the dyke margins suggests that these fluids also served to dehydrate the country rocks. This dyke may thus be representative of the widespread transport of carbonic fluids in this terrain by felsic magmas.
RP FARQUHAR, J (corresponding author), UNIV ALBERTA,DEPT GEOL,EDMONTON T6G 2E3,ALBERTA,CANADA.
NR 35
TC 50
Z9 52
U1 0
U2 12
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 60
EP 63
DI 10.1038/354060a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900057
DA 2026-03-10
ER

PT J
AU SCHMID, RM
   PERKINS, ND
   DUCKETT, CS
   ANDREWS, PC
   NABEL, GJ
AF SCHMID, RM
   PERKINS, ND
   DUCKETT, CS
   ANDREWS, PC
   NABEL, GJ
TI CLONING OF AN NF-KAPPA-B SUBUNIT WHICH STIMULATES HIV TRANSCRIPTION IN SYNERGY WITH P65
SO NATURE
LA English
DT Article
ID enhancer binding-protein; c-rel; v-rel; reticuloendotheliosis virus; nucleotide-sequence; oncogene; dna; dorsal; expression; gene
AB THE transcription factor NF-kappa-B is a protein complex which comprises a DNA-binding subunit and an associated transactivation protein (of relative molecular masses 50,000 (50K) and 65K, respectively) 1,2.  Both the 50K and 65K subunits have similarity with the rel oncogene and the Drosophila maternal effect gene dorsal 3-6.  The 50K DNA-binding subunit was previously thought to be a unique protein, derived from the 105K gene product (p105). We now report the isolation of a complementary DNA that encodes an alternative DNA-binding subunit of NF-kappa-B. It is more similar to p105 NF-kappa-B than other family members and defines a new subset of rel-related genes. It is synthesized as a approximately 100K protein (p100) that is expressed in different cell types, contains cell cycle motifs and, like p105, must be processed to generate a 50K form. A 49K product (p49) can be generated independently from an alternatively spliced transcript; it has specific kappa-B DNA-binding activity and can form heterodimers with other rel proteins. In contrast to the approximately 50K protein derived from p105, p49 acts in synergy with p65 to stimulate the human immunodeficiency virus (HIV) enhancer in transiently transfected Jurkat cells. p49/p100 NF-kappa-B could therefore be important in the regulation of HIV and other kappa-B-containing genes.
C1 UNIV MICHIGAN,MED CTR,HOWARD HUGHES MED INST,DEPT INTERNAL MED,ANN ARBOR,MI 48109.
   UNIV MICHIGAN,MED CTR,HOWARD HUGHES MED INST,DEPT BIOL CHEM,ANN ARBOR,MI 48109.
C3 University of Michigan System; University of Michigan; Howard Hughes Medical Institute; Howard Hughes Medical Institute; University of Michigan System; University of Michigan
NR 26
TC 389
Z9 402
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 733
EP 736
DI 10.1038/352733a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400065
PM 1876189
DA 2026-03-10
ER

PT J
AU ENDO, I
   SOEDA, E
   MURAKAMI, Y
   NISHI, K
AF ENDO, I
   SOEDA, E
   MURAKAMI, Y
   NISHI, K
TI HUMAN GENOME ANALYSIS SYSTEM
SO NATURE
LA English
DT Article
RP ENDO, I (corresponding author), INST PHYS & CHEM RES,DIV GENOME RES,TSUKUBAO,IBARAKI 305,JAPAN.
NR 3
TC 7
Z9 8
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 89
EP 90
DI 10.1038/352089a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800080
PM 2062384
DA 2026-03-10
ER

PT J
AU MAHENDRAN, R
   SPOTTSWOOD, MR
   MILLER, DL
AF MAHENDRAN, R
   SPOTTSWOOD, MR
   MILLER, DL
TI RNA EDITING BY CYTIDINE INSERTION IN MITOCHONDRIA OF PHYSARUM-POLYCEPHALUM
SO NATURE
LA English
DT Article
ID nucleotide-sequence; messenger-rna; trypanosome mitochondria; plant-mitochondria; alpha-subunit; atp-synthase; stop codon; protein; operon; gene
AB A COROLLARY of the central dogma of molecular biology is that genetic information passes from DNA to RNA by the continuous synthesis of RNA on a DNA template.  The demonstration of RNA editing 1 (the specific insertion, deletion or substitution of residues in RNA to create an RNA with a sequence different from its owen template) raised the possibility that is some cases not all of the genetic information for a trait resides in the DNA template.  Two different types of RNA editing have been identified in mitochondria:  insertional editing represented by the extensive insertion (and occasional deletion) of uridine residues in mitochondrial RNAs of the kinetoplastid protozoa 2-4 and the substitutional editing represented by the cytidine to uridine substitutions in some plant mitochondria 5-7.  these editing types have not been shown to be present in the same organism of may have very different mechanisms.  RNA editing of both types has been observed in nonmitochondrial systems 8-17 but it is not as extensive and may involve still different mechanisms.  Here we report the discovery of extensive insertional RNA editing in mitochondria from an organism other than a kinetoplastid protozoan.  The mitochondrial RNA apparently encoding the alpha-subunit of ATP synthetase in the acellular slime mould,  Physarum polycephalum, is edited at 54 sites by cytidine insertion.
RP MAHENDRAN, R (corresponding author), UNIV TEXAS,CELL & MOLEC BIOL PROGRAM,BOX 830688,RICHARDSON,TX 75083, USA.
NR 34
TC 123
Z9 134
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 434
EP 438
DI 10.1038/349434a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400058
PM 1825131
DA 2026-03-10
ER

PT J
AU ALFORD, NM
   BUTTON, TW
   ADAMS, MJ
   HEDGES, S
   NICHOLSON, B
   PHILLIPS, WA
AF ALFORD, NM
   BUTTON, TW
   ADAMS, MJ
   HEDGES, S
   NICHOLSON, B
   PHILLIPS, WA
TI LOW SURFACE-RESISTANCE IN YBA2CU3OX MELT-PROCESSED THICK-FILMS
SO NATURE
LA English
DT Article
ID jc
AB A LOW surface resistance, R(s), is the key to successful development of radio-frequency and microwave applications of high-temperature superconductors.  Here we report the R(s) of YBa2Cu3O(x) thick films on yttria-stabilized zirconia substrates at frequencies up to 50 GHz. Films processed below the peritectic temperature are fine grained, have R(s) similar to bulk YBa2Cu3O(x), generally have low critical current density (J(c)) and exhibit little preferred orientation of crystallographic axes.  Films processed above the peritectic temperature exhibit preferred orientation in large spherulitic grains, have higher J(c) and far lower R(s).  For these films the crossover frequency at which R(s) equals that of copper is 50 GHz, a factor of two higher than the best bulk material or thick film yet reported and only a factor of approximately 4 lower than high-quality thin films.  At the frequencies used for mobile communications (900 MHz and 1.8 GHz), the superconductor losses would be two orders of magnitude lower than those of normal metals.  The particular advantages of the thick-film route are the speed and low cost of the process, and the ability to apply the films on curved surfaces and on large areas, the largest so far being > 200 cm2.
C1 GEC MARCONI RES,CHELMSFORD CM2 8HN,ESSEX,ENGLAND.
   GEC HIRST RES LABS,WEMBLEY HA9 7PP,MIDDX,ENGLAND.
RP ALFORD, NM (corresponding author), ICI PLC,ADV MAT,POB 11,HEATH,RUNCORN WA7 4QE,CHESHIRE,ENGLAND.
NR 13
TC 63
Z9 66
U1 1
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 680
EP 683
DI 10.1038/349680a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700041
DA 2026-03-10
ER

PT J
AU PETITOU, M
   LORMEAU, JC
   CHOAY, J
AF PETITOU, M
   LORMEAU, JC
   CHOAY, J
TI CHEMICAL SYNTHESIS OF GLYCOSAMINOGLYCANS - NEW APPROACHES TO ANTITHROMBOTIC DRUGS
SO NATURE
LA English
DT Article
ID heparin pentasaccharide fragment; molecular-weight heparin; high-affinity; binding sequence; chromatography; separation; thrombosis; mechanism
AB Sanofi, Elf Aquitaine's pharmaceutical subsidiary is a world leader in antithrombotic drugs.  This article traces the development of Heparin-based antithrombotic drugs and describes the company's progress in producing synthetic substitutes.
RP PETITOU, M (corresponding author), SANOFI RECH,9 RUE PRESIDENT SALVADOR ALLENDE,F-94256 GENTILLY,FRANCE.
NR 40
TC 54
Z9 58
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 30
EP 33
DI 
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH681
UT WOS:A1991FH68100011
PM 2017262
DA 2026-03-10
ER

PT J
AU MOHR, G
   LAMBOWITZ, AM
AF MOHR, G
   LAMBOWITZ, AM
TI INTEGRATION OF A GROUP-I INTRON INTO A RIBOSOMAL-RNA SEQUENCE PROMOTED BY A TYROSYL-TRANSFER RNA-SYNTHETASE
SO NATURE
LA English
DT Article
ID neurospora mitochondria; involvement; invitro
AB GROUP I and II introns are mobile elements that propagate by insertion into different genes 1. Some introns of both types self-splice in vitro by transesterification reactions catalysed by the intron RNA 2. These transesterifications are reversible 3-5, and it has been suggested that reverse splicing followed by reverse transcription and recombination with genomic DNA may be a mechanism for intron transposition 6-7. In vivo the splicing of many, if not all, group I and II introns requires protein factors, which may facilitate correct folding of the intron RNAs 8. Here we show that the Neurospora mitochondrial large rRNA intron, a group I intron that is not self-splicing in vitro 9, undergoes reverse splicing in a reaction promoted by the CYT-18 protein, the Neurospora mitochondrial tyrosyl-tRNA synthetase, which is required for splicing the intron in vivo 10. In contrast to known RNA-catalysed reverse splicing reactions, this protein-assisted reverse splicing is sufficiently rapid to compete with forward splicing at low RNA concentrations under physiologically relevant conditions, including high GTP and low Mg2+ concentrations. Our results indicate that proteins that promote splicing could contribute to intron mobility by promoting reverse splicing in vivo.
C1 OHIO STATE UNIV,DEPT MOLEC GENET,484 W 12TH AVE,COLUMBUS,OH 43210.
   OHIO STATE UNIV,CTR BIOTECHNOL,COLUMBUS,OH 43210.
   OHIO STATE UNIV,DEPT BIOCHEM,COLUMBUS,OH 43210.
C3 University System of Ohio; Ohio State University; University System of Ohio; Ohio State University; University System of Ohio; Ohio State University
NR 17
TC 23
Z9 26
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 14
PY 1991
VL 354
IS 6349
BP 164
EP 167
DI 10.1038/354164a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GP880
UT WOS:A1991GP88000065
PM 1658660
DA 2026-03-10
ER

PT J
AU VONMOLLARD, GF
   SUDHOF, TC
   JAHN, R
AF VONMOLLARD, GF
   SUDHOF, TC
   JAHN, R
TI A SMALL GTP-BINDING PROTEIN DISSOCIATES FROM SYNAPTIC VESICLES DURING EXOCYTOSIS
SO NATURE
LA English
DT Article
ID secretion; membrane; glutamate; suggests; calcium; release
AB LOW-molecular-weight GTP-binding proteins are strong candidates for regulators of membrane traffic1-3.  In yeast, mutations in the sec4 or ypt1 genes encoding small GTP-binding proteins inhibit constitutive membrane flow at the plasma membrane or Golgi complex, respectively4-6. It has been suggested that membrane fusion-fission events are regulated by cycling of small GTP-binding proteins between a membrane-bound and free state7, but although most of these small proteins are found in both soluble and tightly membrane-bound forms, there is no direct evidence to support such cycling.  In rat brain a small GTP-binding protein, rab3A, is exclusively associated with synaptic vesicles, the secretory organelles of nerve terminals8,9.  Here we use isolated nerve terminals to study the fate of rab3A during synaptic vesicle exocytosis.  We find that rab3A dissociates quantitatively from the vesicle membrane after Ca2+-dependent exocytosis and that this dissociation is partially reversible during recovery after stimulation.  These results are direct evidence for an association-dissociation cycle of a small GTP-binding protein during traffic of its host membrane.
C1 MAX PLANCK INST PSYCHIAT,DEPT NEUROCHEM,KLOPFERSPITZ 18A,W-8033 MARTINSRIED,GERMANY.
   UNIV TEXAS,SW MED CTR,HOWARD HUGHES MED INST,DALLAS,TX 75235.
C3 Max Planck Society; Howard Hughes Medical Institute; University of Texas System; University of Texas Southwestern Medical Center; University of Texas Dallas
NR 20
TC 308
Z9 332
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 79
EP 81
DI 10.1038/349079a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100057
PM 1845915
DA 2026-03-10
ER

PT J
AU BONHOEFFER, T
   GRINVALD, A
AF BONHOEFFER, T
   GRINVALD, A
TI ISO-ORIENTATION DOMAINS IN CAT VISUAL-CORTEX ARE ARRANGED IN PINWHEEL-LIKE PATTERNS
SO NATURE
LA English
DT Article
ID monkey striate cortex; functional architecture; intrinsic signals; organization; columns; geometry
AB THE mammalian cortex is organized in a columnar fashion:  neurons lying below each other from the pia to the white matter usually share many functional properties.  Across the cortical surface, cells with similar response properties are also clustered together, forming elongated bands or patches.  Some response properties, such as orientation preference in the visual cortex, change gradually across the cortical surface forming 'orientation maps'.  To determine the precise layout of iso-orientation domains, knowledge of responses not only to one but to many stimulus orientations is essential.  Therefore, the exact depiction of orientation maps has been hampered by technical difficulties and remained controversial for almost thirty years.  Here we use in vivo optical imaging based on intrinsic signals to gather information on the responses of a piece of cortex to gratings in many different orientations.  This complete set of responses then provides detailed information on the structure of the orientation map in a large patch of cortex from area 18 of the cat.  We find that cortical regions that respond best to one orientation form highly ordered patches rather than elongated bands.  These iso-orientation patches are organized around 'orientation centres', producing pinwheel-like patterns in which the orientation preference of cells is changing continuously across the cortex.  We have also analysed our data for fast changes in orientation preference and find that these 'fractures' are limited to the orientation centres.  The pinwheels and orientation centres are such a prominent organizational feature that it should be important to understand their development as well as their function in the processing of visual information.
C1 ROCKEFELLER UNIV,NEUROBIOL LAB,NEW YORK,NY 10021.
   IBM CORP,DIV RES,YORKTOWN HTS,NY 10598.
   WEIZMANN INST SCI,IL-76100 REHOVOT,ISRAEL.
C3 Rockefeller University; International Business Machines (IBM); IBM USA; Weizmann Institute of Science
NR 18
TC 676
Z9 755
U1 0
U2 31
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 429
EP 431
DI 10.1038/353429a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600056
PM 1896085
DA 2026-03-10
ER

PT J
AU SUN, XJ
   ROTHENBERG, P
   KAHN, CR
   BACKER, JM
   ARAKI, E
   WILDEN, PA
   CAHILL, DA
   GOLDSTEIN, BJ
   WHITE, MF
AF SUN, XJ
   ROTHENBERG, P
   KAHN, CR
   BACKER, JM
   ARAKI, E
   WILDEN, PA
   CAHILL, DA
   GOLDSTEIN, BJ
   WHITE, MF
TI STRUCTURE OF THE INSULIN-RECEPTOR SUBSTRATE IRS-1 DEFINES A UNIQUE SIGNAL TRANSDUCTION PROTEIN
SO NATURE
LA English
DT Article
ID growth factor-i; tyrosine-phosphorylation; phosphatidylinositol kinase; cells; adipocytes; common; phosphoprotein; purification; 3-kinase; binding
AB SINCE the discovery of insulin nearly 70 years ago, there has been no problem more fundamental to diabetes research than understanding how insulin works at the cellular level. Insulin binds to the alpha-subunit of the insulin receptor which activates the tyrosine kinase in the beta-subunit, but the molecular events linking the receptor kinase to insulin-sensitive enzymes and transport processes are unknown 1,2. Our discovery that insulin stimulates tyrosine phosphorylation of a protein of relative molecular mass between 165,000 and 185,000, collectively called pp185, showed that the insulin receptor kinase has specific cellular substrates 3. The pp185 is a minor cytoplasmic phosphoprotein found in most cells and tissues 4-10; its phosphorylation is decreased in cells expressing mutant receptors defective in signalling 6,11. We have now cloned IRS-1, which encodes a component of the pp185 band. IRS-1 contains over ten potential tyrosine phosphorylation sites, six of which are in Tyr-Met-X-Met motifs. During insulin stimulation, the IRS-1 protein undergoes tyrosine phosphorylation and binds phosphatidylinositol 3-kinase, suggesting that IRS-1 acts as a multisite 'docking' protein to bind signal-transducing molecules containing Src-homology 2 and Src-homology-3 domains 12-14. Thus IRS-1 may link the insulin receptor kinase and enzymes regulating cellular growth and metabolism.
RP SUN, XJ (corresponding author), HARVARD UNIV,SCH MED,DEPT MED,JOSLIN DIABET CTR,DIV RES,1 JOSLIN PL,BOSTON,MA 02115, USA.
NR 31
TC 1454
Z9 1610
U1 0
U2 61
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 4
PY 1991
VL 352
IS 6330
BP 73
EP 77
DI 10.1038/352073a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FV178
UT WOS:A1991FV17800074
PM 1648180
DA 2026-03-10
ER

PT J
AU BURTON, FH
   HASEL, KW
   BLOOM, FE
   SUTCLIFFE, JG
AF BURTON, FH
   HASEL, KW
   BLOOM, FE
   SUTCLIFFE, JG
TI PITUITARY HYPERPLASIA AND GIGANTISM IN MICE CAUSED BY A CHOLERA-TOXIN TRANSGENE
SO NATURE
LA English
DT Article
ID hormone-releasing-factor; adenylate-cyclase activity; growth-hormone; gene; expression; cells; mechanisms; injection; ablation; invitro
AB CYCLIC AMP 1 is thought to act as an intracellular second messenger, mediating the physiological response of many cell types to extracellular signals 2,3. In the pituitary, growth hormone (GH)-producing cells (somatotrophs) proliferate and produce GH in response to hypothalamic GH-releasing factor 4-8, which binds a receptor that stimulates G(s) protein activation of adenylyl cyclase 3,9-12. We have now determined whether somatotroph proliferation and GH production are stimulated by cAMP alone 5,7,11,13-15, or require concurrent, non-G(s)-mediated induction of other regulatory molecules by designing a transgene to induce chronic supraphysiological concentrations of cAMP in somatotrophs. The rat GH promoter 16,17 was used to express an intracellular form of cholera toxin 18, a non-cytotoxic and irreversible activator of G(s) (ref. 19). Introduction of this transgene into mice caused gigantism, elevated serum GH levels, somatotroph proliferation and pituitary hyperplasia. These results support the direct triggering of these events by cAMP, and illustrate the utility of cholera toxin transgene as a tool for physiological engineering.
C1 SCRIPPS RES INST, DEPT NEUROPHARMACOL, LA JOLLA, CA 92037 USA.
C3 Scripps Research Institute
RP BURTON, FH (corresponding author), SCRIPPS RES INST, DEPT MOLEC BIOL, 10666 N TORREY PINES RD, LA JOLLA, CA 92037 USA.
NR 27
TC 179
Z9 184
U1 0
U2 2
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD MAR 7
PY 1991
VL 350
IS 6313
BP 74
EP 77
DI 10.1038/350074a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FA693
UT WOS:A1991FA69300069
PM 1848356
DA 2026-03-10
ER

PT J
AU STAFFELBACH, T
   NEFTEL, A
   STAUFFER, B
   JACOB, D
AF STAFFELBACH, T
   NEFTEL, A
   STAUFFER, B
   JACOB, D
TI A RECORD OF THE ATMOSPHERIC METHANE SINK FROM FORMALDEHYDE IN POLAR ICE CORES
SO NATURE
LA English
DT Article
ID increase; ch4
AB MEASUREMENTS of methane from ice cores show that the atmospheric concentration of methane has more than doubled since industrialization, and was only half of the pre-industrial value during the last ice age 1-9.  Natural sources of atmospheric methane are mainly biogenic, with the main sink for methane being its reaction with OH radicals. This reaction initiates a chain of reactions involving other trace gases and radicals, one of which is formaldehyde.  In the remote troposphere, oxidation of methane followed by other reactions is the main source for formaldehyde.  By reconstructing records of atmospheric methane and formaldehyde from ice cores, we can examine changes in sources of methane and in the oxidation capacity of the atmosphere.
C1 HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138.
C3 Harvard University
RP STAFFELBACH, T (corresponding author), UNIV BERN,INST PHYS,SIDLERSTR 5,CH-3012 BERN,SWITZERLAND.
NR 21
TC 95
Z9 103
U1 1
U2 29
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 14
PY 1991
VL 349
IS 6310
BP 603
EP 605
DI 10.1038/349603a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EX570
UT WOS:A1991EX57000057
DA 2026-03-10
ER

PT J
AU ZHANG, Z
   CHEN, CC
   KELTY, SP
   DAI, HJ
   LIEBER, CM
AF ZHANG, Z
   CHEN, CC
   KELTY, SP
   DAI, HJ
   LIEBER, CM
TI THE SUPERCONDUCTING ENERGY-GAP OF RB3C60
SO NATURE
LA English
DT Article
AB THE discovery of superconductivity in potassium-doped C60 (ref. 1) has been followed by an intense effort to understand the physics and chemistry of metal-doped fullerene solids 2-13.  Experimental studies of alkali-metal-doped C60 have now provided insight into the structure 7,13 and the coherence length and penetration depth 4 of the superconducting phase.  No measurements of the superconducting energy gap (DELTA) have, however, been reported.  The BCS theory of superconductivity 15, which has been used to interpret much of this experimental work 2,4,9-13, predicts (in the limit of weak coupling) that the reduced energy gap 2-DELTA/kT(c) has a material-independent value of 3.53.  Values in excess of 3.5 define strong coupling, and thus provide insight into the nature of the pairing mechanism.  Here we describe the measurement of DELTA for single-phase superconducting Rb3C60 by tunnelling spectroscopy using a scanning tunnelling microscope.  We obtain a value of DELTA at 4.2 K of 6.6 +/- 0.4 meV, corresponding to a reduced energy gap of 5.3.  This is significantly larger than predicted by BCS theory, but similar in magnitude to values found for high-temperature copper oxide superconductors 14.  Our finding of strong coupling in Rb3C60 suggests the need for caution in using standard BCS theory to interpret superconductivity in metal-doped C60.
C1 HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138.
   HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138.
C3 Harvard University; Harvard University
NR 21
TC 108
Z9 114
U1 0
U2 40
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 333
EP 335
DI 10.1038/353333a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400052
DA 2026-03-10
ER

PT J
AU VIERECK, RA
   MURAD, E
   GREEN, BD
   JOSHI, P
   PIKE, CP
   HIEB, R
   HARBAUGH, G
AF VIERECK, RA
   MURAD, E
   GREEN, BD
   JOSHI, P
   PIKE, CP
   HIEB, R
   HARBAUGH, G
TI ORIGIN OF THE SHUTTLE GLOW
SO NATURE
LA English
DT Article
ID vehicle glow; surface; satellite; no2
AB A GLOW around exposed surfaces of the space shuttle facing the direction of orbital motion was first seen in 1983 1,2.  This 'shuttle glow' extends about 10 cm from the surfaces, is peaked in wavelength at 680 nm, and within a resolution of about 3.5 nm forms a continuum 3-6.  Similar anomalies were reported in rocket experiments as long ago as 1958 7 and in more recent space-based studies 8. Apart from its interest as an unusual physical phenomenon, shuttle glow may be a source of interference in space-based spectroscopy; anomalous airglow observations made by the Atmospheric Explorer spacecraft 9,10 have been attributed to it. The most likely explanation seems to be the recombination of fast oxygen atoms in the upper atmosphere with NO absorbed on the shuttle's surface. This forms excited NO2, which radiates light as it desorbs 6,7. On a recent shuttle mission (STS-39) four gases, NO, CO2, Xe and Ne were released for a plasma experiment. Unintentionally, enough gas was scattered onto the surfaces of the shuttle tail that when NO was released a much more intense version of shuttle glow was observed. The other gases did not affect the normal shuttle glow. Under normal conditions the adsorbed NO that causes the glow probably comes either from the ambient atmosphere 6 or from reactions in exhaust gases from the shuttle thrusters 14,15.
C1 PHYS SCI INC,ANDOVER,MA 01810.
   NASA,JOHNSON SPACE CTR,HOUSTON,TX 77001.
C3 Physical Sciences Inc.; National Aeronautics & Space Administration (NASA)
RP VIERECK, RA (corresponding author), PHILLIPS LAB,BEDFORD,MA 01731, USA.
NR 26
TC 21
Z9 22
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 48
EP 50
DI 10.1038/354048a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900052
DA 2026-03-10
ER

PT J
AU GARCHON, HJ
   BEDOSSA, P
   ELOY, L
   BACH, JF
AF GARCHON, HJ
   BEDOSSA, P
   ELOY, L
   BACH, JF
TI IDENTIFICATION AND MAPPING TO CHROMOSOME-1 OF A SUSCEPTIBILITY LOCUS FOR PERIINSULITIS IN NONOBESE DIABETIC MICE
SO NATURE
LA English
DT Article
ID mellitus; mouse; pancreas; insulitis; islets; gene; hla
AB INSULIN-DEPENDENT diabetes mellitus (IDDM) is a polygenic disease caused by autoimmune destruction of insulin-producing beta-cells in the islets of Langerhans 1,2. Its onset is preceded by a long and variable period in which lymphoid cells infiltrate the pancreas but first remain outside the islets (peri-insulitis) before invading them (insulitis) 3-7. Among susceptibility loci, only the major histocompatibility complex (MHC) has been clearly assigned 8-12. Genetic study of the nonobese diabetic (NOD) mouse model for insulin-dependent diabetes mellitus has revealed genetic linkage of insulitis and of early onset diabetes with two non-MHC loci mapping to chromosome 3 and 11 respectively 13. Here we report a close association of periinsulitis with a third non-MHC locus mapping to chromosome 1. Successive stages in the progression of diabetic disease thus appear to be controlled by distinct genes or sets of genes.
C1 HOP ANTOINE BECLERE, SERV ANAT PATHOL, F-92140 CLAMART, FRANCE.
C3 Assistance Publique Hopitaux Paris (APHP); Hopital Universitaire Antoine-Beclere - APHP
RP GARCHON, HJ (corresponding author), HOP NECKER ENFANTS MALAD, INSERM, U25, 161 RUE SEVRES, F-75743 PARIS 15, FRANCE.
NR 25
TC 140
Z9 143
U1 0
U2 0
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 260
EP 262
DI 10.1038/353260a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400060
PM 1896073
DA 2026-03-10
ER

PT J
AU MORGAN, VI
   GOODWIN, ID
   ETHERIDGE, DM
   WOOKEY, CW
AF MORGAN, VI
   GOODWIN, ID
   ETHERIDGE, DM
   WOOKEY, CW
TI EVIDENCE FROM ANTARCTIC ICE CORES FOR RECENT INCREASES IN SNOW ACCUMULATION
SO NATURE
LA English
DT Article
AB LARGE uncertainties exist in the present knowledge of the ma budget of the Antarctic ice sheet, because of a lack of data on the rates of both ice outflow and snow accumulation 1. Present estimates indicate that both the outflow and the net accumulation are approximately equal to 2,000 km3 of ice per year (equivalent to about 6 mm of sea level) 2. The temporal variation of accumulation rate is central to determinations of the mass budget, because accumulation can change rapidly in response to short-term climate variations, whereas ice flow varies only on longer timescales. Here we present time series showing changes in the net rate of snow accumulation since 1806 along a 700-km segment of East Antarctica. The accumulation record was derived from the thicknesses of annual layers in ice cores, deduced from seasonal variations in oxygen isotope ratio and in ice-crust stratigraphy. We find a significant increase in the accumulation rate following a minimum around 1960, leading to recent rates that are about 20% above the long-term mean. If this recent increase is widespread, as suggested by shorter-term accumulation data from across a large part of Antarctica, the positive imbalance (5-25% of the mass input) shown in recent studies of the ice sheet's mass budget 1 may have existed only since the late 1960s. We estimate that this increase in accumulation rate should contribute to a lowering of sea level of 1.0-1.2 mm per year.
C1 CSIRO,DIV ATMOSPHER RES,MORDIALLOC,VIC 3195,AUSTRALIA.
C3 Commonwealth Scientific & Industrial Research Organisation (CSIRO)
RP MORGAN, VI (corresponding author), AUSTRALIAN ANTARCT DIV,CHANNEL HIGHWAY,KINGSTON 7050,AUSTRALIA.
NR 21
TC 90
Z9 106
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 7
PY 1991
VL 354
IS 6348
BP 58
EP 60
DI 10.1038/354058a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GN829
UT WOS:A1991GN82900056
DA 2026-03-10
ER

PT J
AU OUYANG, Q
   SWINNEY, HL
AF OUYANG, Q
   SWINNEY, HL
TI TRANSITION FROM A UNIFORM STATE TO HEXAGONAL AND STRIPED TURING PATTERNS
SO NATURE
LA English
DT Article
ID equilibrium phase-transitions; system; waves
AB CHEMICAL travelling waves have been studied experimentally for more than two decades 1-5, but the stationary patterns predicted by Turing 6 in 1952 were observed only recently 7-9, as patterns localized along a band in a gel reactor containing a concentration gradient in reagents. The observations are consistent with a mathematical model for their geometry of reactor 10 (see also ref. 11). Here we report the observation of extended (quasi-two-dimensional) Turning patterns and of a Turing bifurcation-a transition, as a control parameter is varied, from a spatially uniform state to a patterned state. These patterns form spontaneously in a thin disc-shaped gel in contact with a reservoir of reagents of the chlorite-iodide-malonic acid reaction 12. Figure 1 shows examples of the hexagonal, striped and mixed patterns that can occur. Turing patterns have similarities to hydrodynamic patterns (see, for example, ref. 13), but are of particular interest because they possess an intrinsic wavelength and have a possible relationship to biological patterns 14-17.
C1 UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712.
C3 University of Texas System; University of Texas Austin
RP OUYANG, Q (corresponding author), UNIV TEXAS,CTR NONLINEAR DYNAM,AUSTIN,TX 78712, USA.
NR 28
TC 757
Z9 808
U1 2
U2 127
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 610
EP 612
DI 10.1038/352610a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100051
DA 2026-03-10
ER

PT J
AU PERROTTA, AT
   BEEN, MD
AF PERROTTA, AT
   BEEN, MD
TI A PSEUDOKNOT-LIKE STRUCTURE REQUIRED FOR EFFICIENT SELF-CLEAVAGE OF HEPATITIS DELTA-VIRUS RNA
SO NATURE
LA English
DT Article
ID genome; site
AB HEPATITIS delta virus genomic and antigenomic RNAs contain a self-cleavage site hypothesized to function in processing the viral RNA during replication 1-3.  Self-cleavage requires only a divalent cation 1-3 and is mediated at the genomic site by a sequence of less than 85 nucleotides 4.  We propose that the genomic self-cleaving sequence element 4 and a corresponding sequence from the antigenomic RNA could generate related secondary structures.  The region of the antigenomic sequence, predicted from the proposed structure, was synthesized and shown to be sufficient for self-cleavage.  Evidence for two stems which form a tertiary interaction was obtained by site-specific mutagenesis of the antigenomic sequence.  Efficient self-cleavage in 10 M formamide or 5 M urea, also a property of the genomic sequence 5, was dependent on base-pairing in both stems.  But in the absence of denaturants, the stem distal to the site of cleavage was not required, suggesting that the tertiary interaction stabilizes the structure required for self-cleavage.
C1 DUKE UNIV,MED CTR,DEPT BIOCHEM,DURHAM,NC 27710.
C3 Duke University
NR 14
TC 306
Z9 390
U1 0
U2 19
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 4
PY 1991
VL 350
IS 6317
BP 434
EP 436
DI 10.1038/350434a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FF042
UT WOS:A1991FF04200054
PM 2011192
DA 2026-03-10
ER

PT J
AU KOMIYAMA, NH
   SHIH, DTB
   LOOKER, D
   TAME, J
   NAGAI, K
AF KOMIYAMA, NH
   SHIH, DTB
   LOOKER, D
   TAME, J
   NAGAI, K
TI WAS THE LOSS OF THE D-HELIX IN ALPHA-GLOBIN A FUNCTIONALLY NEUTRAL MUTATION
SO NATURE
LA English
DT Article
ID escherichia-coli; hemoglobin; expression; sequences; myoglobin
AB PROTEINS in the globin family are found in a variety of species from bacteria to man 1-3.  From the many globin sequences known, evolutionary trees have been constructed showing that alpha and beta-globins diverged from a common ancestor between 425 and 500 million years ago, after vertebrate species had appeared and roughly when sharks and bony vertebrates diverged 4-6.  The alpha and beta-globins assemble to form tetrameric haemoglobin, alpha-2-beta-2, which can switch between quaternary states having high and low oxygen affinity 7.  This allows the protein to bind oxygen cooperatively and therefore efficiently transport oxygen from the lungs to respiring tissues. The alpha and beta-globins have closely related tertiary structures, being alpha-helical proteins with similar haem-binding sites. Most globins consist of eight helices, designated A to H from the N terminus, connected by short nonhelical segments, but all known vertebrate alpha-globins lack a D helix. Because the loss of this helix by alpha-globin occurred shortly before tetrameric haemoglobin appeared, it might be a functionally important mutation required for a tetramer assembly or allostery. We have now tested this idea by engineering human haemoglobins containing beta-subunits without a D helix and alpha-subunits with a D helix. Both of these mutations have little effect on the oxygen-binding properties of the molecule. Thus it is possible that deletion of the D helix in the alpha-subunit was caused by a neutral mutation 8.
C1 MRC,MOLEC BIOL LAB,HILLS RD,CAMBRIDGE CB2 2QH,ENGLAND.
   OREGON HLTH SCI UNIV,DEPT BIOCHEM,PORTLAND,OR 97201.
   STOMATOGEN INC,BOULDER,CO 80301.
C3 MRC Laboratory Molecular Biology; Oregon Health & Science University
NR 22
TC 23
Z9 24
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 349
EP 351
DI 10.1038/352349a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900076
PM 1852211
DA 2026-03-10
ER

PT J
AU CLACKSON, T
   HOOGENBOOM, HR
   GRIFFITHS, AD
   WINTER, G
AF CLACKSON, T
   HOOGENBOOM, HR
   GRIFFITHS, AD
   WINTER, G
TI MAKING ANTIBODY FRAGMENTS USING PHAGE DISPLAY LIBRARIES
SO NATURE
LA English
DT Article
ID immunoglobulin variable domains; polymerase chain-reaction; escherichia-coli; immune-response; expression; protein; lambda; dna; anti-2-phenyloxazolone; repertoire
AB To by-pass hybridoma technology and animal immunization, we are trying to build antibodies in bacteria by mimicking features of immune selection1. Recently we used fd phage2 to display antibody fragments fused to a minor coat protein3,4, allowing enrichment of phage with antigen3. Using a random combinatorial library of the rearranged heavy (VH) and kappa (V-kappa) light chains5-8 from mice immune to the hapten 2-phenyloxazol-5-one (phOx), we have now displayed diverse libraries of antibody fragments on the surface of fd phage. After a single pass over a hapten affinity column, fd phage with a range of phOx binding activities were detected, at least one with high affinity (dissociation constant, K(d) = 10(-8) M). A second pass enriched for the strong binders at the expense of the weak. The binders were encoded by V genes similar to those found in anti-phOx hybridomas but in promiscuous combinations (where the same V gene is found with several different partners). By combining a promiscuous VH or V-kappa gene with diverse repertoires of partners to create hierarchical libraries, we elicited many more pairings with strong binding activities. Phage display offers new ways of making antibodies from V-gene libraries, altering V-domain pairings and selecting for antibodies with good affinities.
C1 CTR PROT ENGN, CAMBRIDGE CB2 2QH, ENGLAND.
C3 University of Cambridge
RP CLACKSON, T (corresponding author), MRC, MOLEC BIOL LAB, HILLS RD, CAMBRIDGE CB2 2QH, ENGLAND.
NR 45
TC 970
Z9 4302
U1 2
U2 179
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 624
EP 628
DI 10.1038/352624a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100057
PM 1907718
DA 2026-03-10
ER

PT J
AU MEYRAND, P
   SIMMERS, J
   MOULINS, M
AF MEYRAND, P
   SIMMERS, J
   MOULINS, M
TI CONSTRUCTION OF A PATTERN-GENERATING CIRCUIT WITH NEURONS OF DIFFERENT NETWORKS
SO NATURE
LA English
DT Article
AB RHYTHMIC motor behaviours are generated within the central nervous system by neuronal circuits called central pattern generators (CPG) 1.  Although a CPG can produce several forms of the same behaviour 2-5 and several circuits may interact to generate different behaviours 6, it is generally assumed that a given CPG consists of a predefined assemblage of neurons that is functionally distinguishable from other circuits.  However, recent studies on the stomatogastric nervous system of crustacea have suggested that CPGs may not be immutable functional entities 7-10.  We now report that under an identified neuromodulatory stimulus, the CPG that produces swallowing-like behaviour of the foregut in lobsters is constructed de novo from neurons belonging to other CPGs.  Consequently neurons operating independently as members of different circuits may be reconfigured into a new pattern-generating circuit that operates differently from the original circuits.  This not only challenges the concept of the CPG being a discrete functional entity, but also demonstrates that a modulatory input can specify an appropriate CPG from a pool of individual neurons of diverse origins.
C1 UNIV BORDEAUX 1,CNRS,NEUROBIOL & PHYSIOL COMPAREES LAB,PL DR PEYNEAU,F-33120 ARCACHON,FRANCE.
C3 Universite de Bordeaux; Centre National de la Recherche Scientifique (CNRS)
NR 14
TC 181
Z9 186
U1 1
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 2
PY 1991
VL 351
IS 6321
BP 60
EP 63
DI 10.1038/351060a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FK193
UT WOS:A1991FK19300059
PM 2027383
DA 2026-03-10
ER

PT J
AU ERSKINE, DJ
   NELLIS, WJ
AF ERSKINE, DJ
   NELLIS, WJ
TI SHOCK-INDUCED MARTENSITIC PHASE-TRANSFORMATION OF ORIENTED GRAPHITE TO DIAMOND
SO NATURE
LA English
DT Article
ID parameters; carbon
AB ONE important method of diamond synthesis is shock compression of graphite and other forms of carbon to high pressures and temperatures, and subsequent quenching to yield metastable diamond.  This process, which occurs in microseconds, happens naturally in the impact of meteors 1,2, within products of explosives 3,4, and by explosive compression of powders 5,6.  A major unresolved issue is whether the shock-induced phase transition of graphite to diamond is martensitic of diffusive.  The relation between the crystal structures of graphite and hexagonal diamond suggests that the phase transition should be fast and martensitic if shock pressure is applied parallel to the c axis (normal to the basal planes) of the graphite crystal structure.  Here we report measurements of shock-wave histories for this transition which show that it occurs in approximately 10 ns.  These results imply that the transformation from graphite to diamond is martensitic for temperatures substantially lower than the melting temperature.  We observe an unexpectedly large sensitivity of kinetics to sample morphology.  As well as answering questions concerning the physical nature of the transformation, our results are relevant to optimization of diamond yield in industrial synthetic methods.
RP ERSKINE, DJ (corresponding author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA.
NR 26
TC 161
Z9 176
U1 1
U2 50
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 317
EP 319
DI 10.1038/349317a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100047
DA 2026-03-10
ER

PT J
AU KOZLOWSKI, S
   TAKESHITA, T
   BOEHNCKE, WH
   TAKAHASHI, H
   BOYD, LF
   GERMAIN, RN
   BERZOFSKY, JA
   MARGULIES, DH
AF KOZLOWSKI, S
   TAKESHITA, T
   BOEHNCKE, WH
   TAKAHASHI, H
   BOYD, LF
   GERMAIN, RN
   BERZOFSKY, JA
   MARGULIES, DH
TI EXCESS BETA-2 MICROGLOBULIN PROMOTING FUNCTIONAL PEPTIDE ASSOCIATION WITH PURIFIED SOLUBLE CLASS-I MHC MOLECULES
SO NATURE
LA English
DT Article
ID major histocompatibility complex; toxic lymphocytes-t; envelope protein; cell hybridomas; antigen; hla; beta-2-microglobulin; recognition; h-2; dissociation
AB T LYMPHOCYTES expressing alpha-beta-receptors recognize antigenic peptide fragments bound to major histocompatibility complex class I (ref. 1) or class II (ref. 2) molecules present on the surface membranes of other cells.  Peptide fragments are present in the two available HLA crystal structures3,4 and recent data indicate that peptide is required for the stable folding of the class I heavy chain and maintenance of its association with the class I light chain beta-2-microglobulin (beta-2-m), at physiological temperature5-7.  To explain how the exogeneous peptide used to create targets for cytotoxic cells bearing CD8 antigen1 could associate with apparently peptide-filled extracellular class I molecules, we hypothesized that stable binding of exogenous peptide to mature class I molecules reflects either the replacement of previously bound peptide during the well documented beta-2m exchange process8 or the loading of 'empty' class I heavy chains dependent on the availability of excess beta-2m.  In either case, free beta-2m should enhance peptide-class I binding.  Using either isolated soluble class I molecules or living cells, we show here that free purified beta-2m markedly augments the generation of antigenic complexes capable of T-cell stimulation.
C1 NIAID,IMMUNOL LAB,LYMPHOCYTE BIOL SECT,BETHESDA,MD 20892.
   NCI,METAB BRANCH,MOLEC IMMUNOGENET & VACCINE RES SECT,BETHESDA,MD 20892.
C3 National Institutes of Health (NIH) - USA; NIH National Institute of Allergy & Infectious Diseases (NIAID); National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI)
RP KOZLOWSKI, S (corresponding author), NIAID,IMMUNOL LAB,MOLEC BIOL SECT,BETHESDA,MD 20892, USA.
NR 23
TC 152
Z9 169
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 74
EP 77
DI 10.1038/349074a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100055
PM 1985269
DA 2026-03-10
ER

PT J
AU HONDA, Z
   NAKAMURA, M
   MIKI, I
   MINAMI, M
   WATANABE, T
   SEYAMA, Y
   OKADO, H
   TOH, H
   ITO, K
   MIYAMOTO, T
   SHIMIZU, T
AF HONDA, Z
   NAKAMURA, M
   MIKI, I
   MINAMI, M
   WATANABE, T
   SEYAMA, Y
   OKADO, H
   TOH, H
   ITO, K
   MIYAMOTO, T
   SHIMIZU, T
TI CLONING BY FUNCTIONAL EXPRESSION OF PLATELET-ACTIVATING-FACTOR RECEPTOR FROM GUINEA-PIG LUNG
SO NATURE
LA English
DT Article
ID cdna; gene; antagonist; rhodopsin; sequence; family; cells
AB PLATELET-activating factor (PAF), a unique phospholipid mediator, possesses potent proinflammatory, smooth-muscle contractile and hypotensive activities, and appears to be crucial in the pathogenesis of bronchial asthma and in the lethality of endotoxin and anaphylactic shock1-3.  Despite this, little is known of the molecular properties of the PAF receptor and related signal transduction systems.  Although several lines of evidence suggest that activation of the PAF receptor stimulates phospholipase C and subsequent inositol trisphosphate formation through G protein(s)4,5, the PAF receptor and calcium channel are reported to show a close relation2,6.  As a first approach to cloning lipid autacoid receptors, we have isolated complementary DNA for the PAF receptors.  Our strategy involved gene expression in Xenopus laevis oocytes and electrophysiological detection of PAF-induced responses.  Sequence analysis indicates that the receptor belongs to the superfamily of G protein-coupled receptors.
C1 UNIV TOKYO,FAC MED,DEPT PHYSIOL CHEM & NUTR,7-3-1 HONGO,BUNKYO KU,TOKYO 113,JAPAN.
   PROT ENGN RES INST,SUITA,OSAKA 565,JAPAN.
   UNIV TOKYO,FAC MED,INST BRAIN RES,DEPT NEUROBIOL,BUNKYO KU,TOKYO 113,JAPAN.
   UNIV TOKYO,FAC MED,DEPT INTERNAL MED & PHYS THERAPY,BUNKYO KU,TOKYO 113,JAPAN.
C3 University of Tokyo; University of Tokyo; University of Tokyo
NR 26
TC 616
Z9 645
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 342
EP 346
DI 10.1038/349342a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100057
PM 1846231
DA 2026-03-10
ER

PT J
AU MARTINELLI, LA
   DEVOL, AH
   VICTORIA, RL
   RICHEY, JE
AF MARTINELLI, LA
   DEVOL, AH
   VICTORIA, RL
   RICHEY, JE
TI STABLE CARBON ISOTOPE VARIATION IN C3 AND C4 PLANTS ALONG THE AMAZON RIVER
SO NATURE
LA English
DT Article
ID c-13/c-12 ratios; rain forests; dioxide; fractionation; leaves; basin
AB ALL plants assimilate C-12 in preference to C-13. As a result of this isotope fractionation, the tissues of subaerial plants have lower C-13/C-12 ratios than that of atmospheric CO2. By contrast, plant respiration and tissue decomposition are accompanied by little, if any, fractionation and hence release C-13-depleted biogenic CO2 back into the atmosphere. If this biogenic CO2 is reassimilated before it is thoroughly mixed into the atmosphere, a further depletion of C-13 in the plant tissue will result. This recycling effect has been found most often in vertical variations of stable isotope composition in tropical forests where plant tissues near the forest floor are more depleted in C-13 (refs 1-5). Here we show that the intensity of biogenic CO2 recycling in flood plain forests of the Amazon systematically increases inland, in the western Amazon basin. We also show that a similar recycling mechanism affects the C-13 composition of semiaquatic grasses owing to evasion of biogenic CO2 from the Amazon river. But in this case the degree of recycling is more pronounced in the eastern basin because the flux of (CO2)-C-13 out of the river is smaller there. Our data indicate that significant spatial carbon isotope gradients can exist across the same general ecosystem, both between different species and also within a single species. Recycling effects therefore need to be taken into account in studies that try to relate plant carbon composition to animal and human diet, and in those attempting to determine the carbon isotope composition of the ancient atmosphere from preserved plant tissues.
C1 CTR ENERGIA NUCL AGR,PIRACICABA 13400,SP,BRAZIL.
   ESCOLA SUPER AGR LUIS DEQUEIROZ,PIRACICABA 13400,SP,BRAZIL.
C3 Universidade de Sao Paulo
RP MARTINELLI, LA (corresponding author), UNIV WASHINGTON,SCH OCEANOG,WB-10,SEATTLE,WA 98195, USA.
NR 20
TC 43
Z9 61
U1 0
U2 41
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 57
EP 59
DI 10.1038/353057a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500055
DA 2026-03-10
ER

PT J
AU WALES, DJ
AF WALES, DJ
TI CALCULATING THE RATE OF LOSS OF INFORMATION FROM CHAOTIC TIME-SERIES BY FORECASTING
SO NATURE
LA English
DT Article
ID spectrum; entropy
AB DETERMINING whether time series of data from dynamical systems exhibit regular, stochastic or chaotic behaviour is a goal in a wide variety of problems.  For sparse time series (those containing only of the order of 1,000 data points), the goal may simply be to discover whether the series are chaotic or not.  Examples are case rates for infectious diseases 1 and proxy palaeoclimatic records from deep-sea cores 2. Sugihara and May 3 have recently extended previous work 4 aimed at distinguishing chaos from noise in sparse time series.  Their approach is based on a comparison  of future predictions of terms in the time series - derived using a data base of information from another part of the series - with the known terms.  Here I present a method for estimating from such forecasting the largest Liapunov exponent of the dynamics, which provides a measure of how chaotic the system is - that is, how rapidly information is lost from the system.
RP WALES, DJ (corresponding author), UNIV CAMBRIDGE,CHEM LABS,LENSFIELD RD,CAMBRIDGE CB2 1EW,ENGLAND.
NR 17
TC 135
Z9 138
U1 0
U2 10
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 485
EP 488
DI 10.1038/350485a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300045
DA 2026-03-10
ER

PT J
AU COSSON, P
   LANKFORD, SP
   BONIFACINO, JS
   KLAUSNER, RD
AF COSSON, P
   LANKFORD, SP
   BONIFACINO, JS
   KLAUSNER, RD
TI MEMBRANE-PROTEIN ASSOCIATION BY POTENTIAL INTRAMEMBRANE CHARGE PAIRS
SO NATURE
LA English
DT Article
ID antigen receptor complex; t-cell receptor; molecular-components; antibody; degradation; igm
AB THE transmembrane domain of the alpha-chain of the T-cell receptor is responsible both for its assembly with the CD3 delta-chain 1 and for rapid degradation of the unassembled chain within the endoplasmic reticulum 2, 3.  The determinant for both assembly and degradation is located in a segment of eight residues containing two basic amino acids (Fig. 1).  We show here that placement of a single basic residue in the transmembrane domain of the Tac antigen can induce interaction with the CD3 chain, through its transmembrane acidic residue.  This interaction is most favoured when the interacting residues are located at the same level in the membrane.  The ability to induce protein-protein interaction by placing charge pairs within transmembrane domains suggests an approach to producing artificial dimers.
RP COSSON, P (corresponding author), NICHHD,CELL BIOL & METAB BRANCH,BETHESDA,MD 20892, USA.
NR 16
TC 235
Z9 251
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 414
EP 416
DI 10.1038/351414a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600061
PM 1827877
DA 2026-03-10
ER

PT J
AU ANDERSON, RM
   GUPTA, S
   MAY, RM
AF ANDERSON, RM
   GUPTA, S
   MAY, RM
TI POTENTIAL OF COMMUNITY-WIDE CHEMOTHERAPY OR IMMUNOTHERAPY TO CONTROL THE SPREAD OF HIV-1
SO NATURE
LA English
DT Article
ID placebo-controlled trial; aids-related complex; azidothymidine azt; zidovudine azt; double-blind; infection
AB WHETHER zidovudine (3'-azido-3'-deoxythymidine, AZT) should be offered to symptomless individuals infected with human immunodeficiency virus type-1 (HIV-1), in the hope of delaying or even preventing progression to AIDS, has been much debated 1.  The discussion has focused on the efficacy of the drug in delaying progression to disease 2, the severity of its side-effects 3, and the likelihood of its prolonged and widespread use resulting in zidovudine-resistant strains of the virus 4. Little attention has been given to the degree to which treatment reduces the infectiousness of symptomless patients, and to the concomitant implications for the overall transmission rate of HIV-1 in the community.  Here we use simple mathematical models to show that community treatment with antiviral drugs or immunotherapies that lengthen the incubation period of AIDS without significantly reducing the infectiousness of treated individuals, can increase the rate at which HIV-1 infection spreads (which is fairly obvious) and can even, under certain circumstances, increase the AIDS-related death rate in the community (which is less obvious).
RP ANDERSON, RM (corresponding author), UNIV LONDON IMPERIAL COLL SCI & TECHNOL,DEPT BIOL,LONDON SW7 2BB,ENGLAND.
NR 18
TC 97
Z9 99
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 356
EP 359
DI 10.1038/350356a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800098
PM 2008214
DA 2026-03-10
ER

PT J
AU TSAI, LH
   HARLOW, E
   MEYERSON, M
AF TSAI, LH
   HARLOW, E
   MEYERSON, M
TI ISOLATION OF THE HUMAN CDK2 GENE THAT ENCODES THE CYCLIN-A-ASSOCIATED AND ADENOVIRUS-E1A-ASSOCIATED P-33 KINASE
SO NATURE
LA English
DT Article
ID adenovirus e1a proteins; region 1a proteins; cell-cycle; fission yeast; m-phase; cdc2; homolog; mitosis; dna; phosphorylation
AB CYCLINS are regulatory subunits which associate with kinases to form complexes that control many of the important steps in cell-cycle progression. The best characterized of the cyclin-containing complexes is the association of cyclin B with the p34cdc2 kinase. The p34cdc2/cyclin B complex is required for the G2 to M transition (see refs 1-4 for review), but the physiological role of other cyclin complexes is unclear. Human cyclin A binds independently to two kinases, associating with either p34cdc2 or a related protein, p33 (refs 5-7). In adenovirus-transformed cells, the viral E1A oncoprotein seems to associate with p33/cyclin A but not with p34cdc2/cyclin A (B. Faha, M.M., L-H.T. and E.H., manuscript submitted). To isolate the gene for p33, we have cloned several novel human cdc2-related genes. The protein product of one of these genes, cdk2 (cyclin-dependent kinase 2), shares 65% sequence identity with p34cdc2 (ref. 8) and 89% identity with the Xenopus Eg-1 gene product 9.  Immunochemical characterization and partial proteolytic mapping show that the cdk2 gene product is the cyclin A-associated p33. Immunoprecipitations of the p33cdk2 protein suggest that it can act as a protein kinase in vitro. As p33cdk2 is bound to cyclin A and is targeted by the viral E1A protein, we suggest that the p33cdk2/cyclin A complex has a unique role in cell-cycle regulation of vertebrate cells.
RP TSAI, LH (corresponding author), MASSACHUSETTS GEN HOSP,CTR CANC,BLDG 149,13TH ST,BOSTON,MA 02129, USA.
NR 35
TC 494
Z9 541
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 12
PY 1991
VL 353
IS 6340
BP 174
EP 177
DI 10.1038/353174a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GE731
UT WOS:A1991GE73100056
PM 1653904
DA 2026-03-10
ER

PT J
AU SCIORTINO, F
   GEIGER, A
   STANLEY, HE
AF SCIORTINO, F
   GEIGER, A
   STANLEY, HE
TI EFFECT OF DEFECTS ON MOLECULAR MOBILITY IN LIQUID WATER
SO NATURE
LA English
DT Article
ID supercooled water; aqueous-solutions; model; ice
AB LIQUID water is a totally connected random network of hydrogen bonds, the connectivity lying well above the percolation threshold 1-3.  But despite this extensive association of hydrogen bonds with strengths greater than the thermal energy, the diffusion and rotation rates of water molecules at ambient temperatures are comparable to those of non-associated simple liquids. Many experiments have indicated that the random tetrahedral network cannot be perfect but must contain defects, which are characterized geometrically by the presence of an extra (fifth) molecule in the first coordination shell, or topologically by the presence of 'bifurcated' hydrogen bonds 4-7.  Here we use molecular-dynamics simulations to examine the effect of such defects on molecular mobility in water. We find that they provide pathways of lower energy between different tetrahedral local arrangements, thus acting as 'catalysts'. The anomalous mobility of water under compression 8,9 and the decreased mobility in hydrophobic hydration shells 10,11 can be interpreted on the same basis. We suggest that our results are relevant to studies on 'stretched' water 12,13.
C1 BOSTON UNIV,DEPT PHYS,BOSTON,MA 02215.
   UNIV DORTMUND,FACHBEREICH CHEM,W-4600 DORTMUND 50,GERMANY.
C3 Boston University; Dortmund University of Technology
RP SCIORTINO, F (corresponding author), BOSTON UNIV,CTR POLYMER STUDIES,BOSTON,MA 02215, USA.
NR 25
TC 329
Z9 341
U1 0
U2 50
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 21
PY 1991
VL 354
IS 6350
BP 218
EP 221
DI 10.1038/354218a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GQ948
UT WOS:A1991GQ94800045
DA 2026-03-10
ER

PT J
AU STRUTHERS, RS
   VALE, WW
   ARIAS, C
   SAWCHENKO, PE
   MONTMINY, MR
AF STRUTHERS, RS
   VALE, WW
   ARIAS, C
   SAWCHENKO, PE
   MONTMINY, MR
TI SOMATOTROPH HYPOPLASIA AND DWARFISM IN TRANSGENIC MICE EXPRESSING A NON-PHOSPHORYLATABLE CREB MUTANT
SO NATURE
LA English
DT Article
ID hormone-releasing factor; nuclear factor creb; somatostatin gene; pituitary; transcription; hyperplasia; binding; protein; cells
AB MOST of the transcriptional effects of cyclic AMP are mediated by the cAMP response element binding protein (CREB) 1, 2.  After activation of cAMP-dependent protein kinase A, the catalytic subunits of this enzyme apparently mediate the phosphorylation and activation of CREB 3, 4.  As cAMP serves as a mitogenic signal for anterior pituitary somatotrophic cells 5, we investigated whether CREB similarly regulates proliferation of these cells.  We prepared transgenic mice expressing a transcriptionally inactive mutant of CREB (CREBM1), which cannot be phosphorylated, in cells of the anterior pituitary.  If CREB activity is required for proliferation, the overexpressed mutant protein would effectively compete with wild-type CREB activity and thereby block the response to cAMP.  As predicted, the CREBM1 transgenic mice exhibited a dwarf phenotype with atrophied pituitary glands markedly deficient in somatotroph but not other cell types.  We conclude that transcriptional activation of CREB is necessary for the normal development of a highly restricted cell type, and that environmental cues, possibly provided by the hypothalamic growth hormone-releasing factor, are necessary for population of the pituitary by somatotrophic cells.
C1 UNIV CALIF SAN DIEGO,GRAD PROGRAM BIOMED SCI,LA JOLLA,CA 92093.
   SALK INST BIOL STUDIES,NEURONAL STRUCT & FUNCT LAB,LA JOLLA,CA 92037.
C3 University of California System; University of California San Diego; Salk Institute
RP STRUTHERS, RS (corresponding author), SALK INST BIOL STUDIES,CLAYTON FDN LABS PEPTIDE BIOL,10010 N TORREY PINES RD,LA JOLLA,CA 92037, USA.
NR 21
TC 270
Z9 286
U1 0
U2 4
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD APR 18
PY 1991
VL 350
IS 6319
BP 622
EP 624
DI 10.1038/350622a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FH112
UT WOS:A1991FH11200063
PM 1826763
DA 2026-03-10
ER

PT J
AU RIND, D
   CHIOU, EW
   CHU, W
   LARSEN, J
   OLTMANS, S
   LERNER, J
   MCCORMICK, MP
   MCMASTER, L
AF RIND, D
   CHIOU, EW
   CHU, W
   LARSEN, J
   OLTMANS, S
   LERNER, J
   MCCORMICK, MP
   MCMASTER, L
TI POSITIVE WATER-VAPOR FEEDBACK IN CLIMATE MODELS CONFIRMED BY SATELLITE DATA
SO NATURE
LA English
DT Article
AB CHIEF among the mechanisms thought to amplify the global climate response to increased concentrations of trace gases is the atmospheric water vapour feedback.  As the oceans and atmosphere warm, there is increased evaporation, and it has been generally thought that the additional moisture then adds to the greenhouse effect by trapping more infrared radiation.  Recently, it has been suggested that general circulation models used for evaluating climate change overestimate this response, and that increased convection in a warmer climate would actually dry the middle and upper troposphere by means of associated compensatory subsidence1.  We use some new satellite-generated water vapour data to investigate this question.  From a comparison of summer and winter moisture values in regions of the middle and upper troposphere that have previously been difficult to observe with confidence, we find that, as the hemispheres warm, increased convection leads to increased water vapour above 500 mbar in approximate quantitative agreement with the results from current climate models.  The same conclusion is reached by comparing the tropical western and eastern Pacific regions.  Thus, we conclude that the water vapour feedback is not overestimated in models and should amplify the climate response to increased trace-gas concentrations.
C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665.
   NOAA,CMDL,BOULDER,CO 80302.
C3 National Aeronautics & Space Administration (NASA); NASA Langley Research Center; National Oceanic Atmospheric Admin (NOAA) - USA
RP RIND, D (corresponding author), NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025, USA.
NR 10
TC 172
Z9 182
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 500
EP 503
DI 10.1038/349500a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100057
DA 2026-03-10
ER

PT J
AU KOSTREWA, D
   GRANZIN, J
   KOCH, C
   CHOE, HW
   RAGHUNATHAN, S
   WOLF, W
   LABAHN, J
   KAHMANN, R
   SAENGER, W
AF KOSTREWA, D
   GRANZIN, J
   KOCH, C
   CHOE, HW
   RAGHUNATHAN, S
   WOLF, W
   LABAHN, J
   KAHMANN, R
   SAENGER, W
TI 3-DIMENSIONAL STRUCTURE OF THE ESCHERICHIA-COLI DNA-BINDING PROTEIN FIS
SO NATURE
LA English
DT Article
ID site-specific recombination; host factor; resolution; inversion; enhancer; lambda; phase; refinement; repressor; growth
AB The factor for inversion stimulation, FIS, is involved in several cellular processes, including site-specific recombination and transcriptional activation 1-4.  In the reactions catalysed by the DNA invertases Gin, Hin and Cin, FIS stimulates recombination by binding to an enhancer sequence 1.  Within the enhancer, two FIS dimers (each 2 x 98 amino acids) 5-7 bind to two 15-base-pair consensus sequences 8,9 (Fig. 1) and induce bending of DNA 10,11.  Current models propose that the enhancer-FIS complex organizes a specific synapse, either through direct interactions with Gin, or by modelling the substrate into a configuration suitable for recombination 1,9,12.  Using X-ray analysis at 2.0 angstrom resolution, we now show that FIS is composed of four alpha-helices tightly intertwined to form a globular dimer with two protruding helix-turn-helix motifs.  The 24 N-terminal amino acids are so poorly defined in the electron density map as to make interpretation doubtful, indicating that they might act as 'feelers' suitable for DNA or protein (invertase) recognition.  We infer from model building that DNA has to bend for tight binding to FIS.
C1 INST GENBIOL FORSCH BERLIN GMBH,W-1000 BERLIN 33,GERMANY.
RP KOSTREWA, D (corresponding author), FREE UNIV BERLIN,INST KRISTALLOG,TAKUSTR 6,W-1000 BERLIN 33,GERMANY.
NR 28
TC 148
Z9 162
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 10
PY 1991
VL 349
IS 6305
BP 178
EP 180
DI 10.1038/349178a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA ER418
UT WOS:A1991ER41800066
PM 1986310
DA 2026-03-10
ER

PT J
AU ALLEN, PB
   RAINER, D
AF ALLEN, PB
   RAINER, D
TI PHONON SUPPRESSION OF COHERENCE PEAK IN NUCLEAR-SPIN RELAXATION RATE OF SUPERCONDUCTORS
SO NATURE
LA English
DT Article
ID alloys
AB THE temperature dependence of the nuclear spin relaxation rate 1/T(1) peaks sharply (the 'Hebel-Slichter' or 'coherence' peak) just below the transition temperature T(c) of a superconductor 1.  Because the observation 2 of this peak definitively confirmed BCS theory 3, its absence 4-6 in the high-T(c) oxide superconductors is the best evidence against a BCS picture.  Here we show that, to the contrary, an extended form of BCS theory gives a natural explanation.  Using the extension by Migdal 7 and Eliashberg 8 to retarded interactions (for phonon coupling, the attraction between electrons propagates at the speed of sound, slower than the Fermi velocity of electrons), we predict unexpectedly strong damping effects in all dynamical properties when the temperature T is close to T(c).  The origin of the damping (which suppresses the coherence peak) is numerous electron-phonon decay channels open to excitations because of the high T(c) itself.  This process still works even if another source of attraction beyond electron-phonon coupling causes the high T(c).  Thus our observations remove a barrier inhibiting conventional descriptions of high-T(c) materials, but by no means force such as interpretation.
C1 NORTHWESTERN UNIV,SCI & TECHNOL CTR SUPERCOND,EVANSTON,IL 60208.
   UNIV BAYREUTH,INST THEORET PHYS 3,W-8580 BAYREUTH,GERMANY.
C3 Northwestern University; University of Bayreuth
RP ALLEN, PB (corresponding author), SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794, USA.
NR 24
TC 125
Z9 126
U1 0
U2 19
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 396
EP 398
DI 10.1038/349396a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400042
DA 2026-03-10
ER

PT J
AU COHEN, JE
   HOROWITZ, P
AF COHEN, JE
   HOROWITZ, P
TI PARADOXICAL BEHAVIOR OF MECHANICAL AND ELECTRICAL NETWORKS
SO NATURE
LA English
DT Article
ID equilibrium
AB WE describe here a network of strings and springs in which cutting a string that supports a weight results in a rise of the weight at equilibrium. In an analogous electronic circuit of passive two-terminal devices (resistors and Zener diodes), adding a current-carrying path increases the voltage drop across the circuit. These systems are mechanical and electrical analogues of a paradox of congested traffic flow 1,2.  Along with similar hydraulic and thermal analogues, they show how non-intuitive equilibrium behaviour can arise in physical networks made up of classical components.
C1 HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138.
C3 Harvard University
RP COHEN, JE (corresponding author), ROCKEFELLER UNIV,1230 YORK AVE,BOX 20,NEW YORK,NY 10021, USA.
NR 13
TC 102
Z9 115
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 22
PY 1991
VL 352
IS 6337
BP 699
EP 701
DI 10.1038/352699a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC064
UT WOS:A1991GC06400051
DA 2026-03-10
ER

PT J
AU KELTY, SP
   CHEN, CC
   LIEBER, CM
AF KELTY, SP
   CHEN, CC
   LIEBER, CM
TI SUPERCONDUCTIVITY AT 30-K IN CESIUM-DOPED C60
SO NATURE
LA English
DT Article
AB RECENTLY there has been significant effort directed towards exploring the physical and chemical properties of C60 and other large carbon clusters 1-11. Particularly intriguing are reports of superconductivity in potassium- and rubidium-doped C60 Crystals and films 5-7. The transition temperatures (T(c)) for K-doped C60 (18 K) and Rb-doped C60 (approximately 28 K) are significantly higher than those reported previously for other molecular superconductors . Earlier attempts to prepare a caesium-doped superconducting phase 7 have proved unsuccessful. Here we report that a Cs-doped superconductor can be prepared by using as the dopant binary alloys of the type CsM (where M is Hg, Tl or Bi). We observe a reproducible superconducting transition in Cs(x)C60 (x = 1.2-3) at 30 K, demonstrated by flux expulsion (the Meissner effect) and flux exclusion (shielding) d.c. magnetization measurements. The low superconducting volume fraction (approximately 1%) suggests that further studies will be needed to determine the optimal doping concentration and to place tighter bounds on T(c).
C1 HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138.
   HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138.
C3 Harvard University; Harvard University
NR 16
TC 216
Z9 237
U1 2
U2 171
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 223
EP 225
DI 10.1038/352223a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500058
DA 2026-03-10
ER

PT J
AU UEMURA, YJ
   KEREN, A
   LE, LP
   LUKE, GM
   STERNLIEB, BJ
   WU, WD
   BREWER, JH
   WHETTEN, RL
   HUANG, SM
   LIN, S
   KANER, RB
   DIEDERICH, F
   DONOVAN, S
   GRUNER, G
   HOLCZER, K
AF UEMURA, YJ
   KEREN, A
   LE, LP
   LUKE, GM
   STERNLIEB, BJ
   WU, WD
   BREWER, JH
   WHETTEN, RL
   HUANG, SM
   LIN, S
   KANER, RB
   DIEDERICH, F
   DONOVAN, S
   GRUNER, G
   HOLCZER, K
TI MAGNETIC-FIELD PENETRATION DEPTH IN K3C60 MEASURED BY MUON SPIN RELAXATION
SO NATURE
LA English
DT Article
ID high-tc superconductors; rotation experiments
AB THE discovery 1-3 of superconductivity in C60 doped with the alkali metals potassium and rubidium has introduced a new family of three-dimensional molecular superconductors 4. The potassium-doped compound 3 K3C60 has a relatively high transition temperature (T(c) = 19.3 K), a very high upper critical field (H(c2)(T --> 0) almost-equal-to 50T) and a short superconducting coherence length 5 (xi = 26 angstrom), in common with the copper oxide superconductors. Here we report muon-spin-relaxation measurements of the magnetic-field penetration depth-lambda in K3C60. The temperature dependence of lambda and of the muon spin relaxation rate indicate that the superconducting energy gap is isotropic, without nodes or zero points. The low-temperature penetration depth-lambda(T --> 0) is about 4,800 angstrom, which implies a ratio of superconducting carrier density to effective mass to be n(s)/(m*/m(e)) = 1.2 x 10(20) cm-3 if one assumes the 'clean limit'. Combining this result with the value of xi, we estimate the Fermi temperature T(F) = 470 K. In the relationship between T(F) and T(c), K3C60 conforms to the trend exhibited by 'exotic' superconductors 6,7 such as the Chevrel phase compounds, the copper oxides and the organic BEDT systems.
C1 UNIV BRITISH COLUMBIA,DEPT PHYS,VANCOUVER V6T 2A3,BC,CANADA.
   TRIUMF,VANCOUVER V6T 2A3,BC,CANADA.
   UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024.
   UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024.
C3 University of British Columbia; University of British Columbia; University of California System; University of California Los Angeles; University of California System; University of California Los Angeles
RP UEMURA, YJ (corresponding author), COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027, USA.
NR 17
TC 212
Z9 214
U1 0
U2 21
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 605
EP 607
DI 10.1038/352605a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100049
DA 2026-03-10
ER

PT J
AU HILL, GE
AF HILL, GE
TI PLUMAGE COLORATION IS A SEXUALLY SELECTED INDICATOR OF MALE QUALITY
SO NATURE
LA English
DT Article
ID poecilia-reticulata; natural-selection; handicap; patterns; guppy
AB FEMALE choice of mates based on the expression of characters that correlate with male quality remains a controversial and largely untested idea 1.  By choosing quality males, females stand to gain resources 2, genetic benefits for their offspring 3-5, or both.  In the house finch (Carpodacus mexicanus), male plumage coloration is a function of dietary intake of carotenoids 6,7.  Here I present results of field studies that indicate that females prefer to mate with colourful males and that plumage brightness correlates with a male's capacity for parental care and perhaps its genotypic quality.  Artificially brightened males paired more quickly and frequently than sham control or lightened males.  Among unmanipulated males, plumage coloration was correlated with nest attentiveness and overwinter survival.  In addition, there was a positive correlation between the coloration of fathers and sons.
C1 UNIV MICHIGAN,DEPT BIOL,ANN ARBOR,MI 48109.
C3 University of Michigan System; University of Michigan
RP HILL, GE (corresponding author), UNIV MICHIGAN,MUSEUM ZOOL,ANN ARBOR,MI 48109, USA.
NR 22
TC 717
Z9 828
U1 1
U2 268
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 337
EP 339
DI 10.1038/350337a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800091
DA 2026-03-10
ER

PT J
AU YEH, E
   DRISCOLL, R
   COLTRERA, M
   OLINS, A
   BLOOM, K
AF YEH, E
   DRISCOLL, R
   COLTRERA, M
   OLINS, A
   BLOOM, K
TI A DYNAMIN-LIKE PROTEIN ENCODED BY THE YEAST SPORULATION GENE SPO15
SO NATURE
LA English
DT Article
ID saccharomyces-cerevisiae; cell-cycle; microtubules
AB THE tightly centromere-linked gene SPO15 is essential for meiotic cell division in the yeast Saccharomyces cerevisiae.  Diploid cells without the intact SPO15 gene product are able to complete premeiotic DNA synthesis and genetic recombination, but are unable to traverse the division cycles.  Electron microscopy of blocked cells reveals a duplicated but unseparated spindle-pole body.  Thus cells are unable to form a bipolar spindle.  Sequence analysis of SPO15 DNA reveals an open reading frame that predicts a protein of 704 amino acids.  This protein is identical to VPS1, a gene involved in vacuolar protein sorting in yeast which has significant sequence homology (45% overall, 66% over 300 amino acids) to the microtubule bundling-protein, dynamin.  The SPO15 gene product expressed in Escherichia coli can be affinity-purified with microtubules.  SPO15 encodes a protein that is likely to be involved in a microtubule-dependent process required for the timely separation of spindle-pole bodies in meiosis
C1 UNIV WASHINGTON,DEPT OTOLARYNGOL,SEATTLE,WA 98195.
   UNIV TENNESSEE,GRAD SCH BIOMED SCI,DIV BIOL,OAK RIDGE NATL LAB,OAK RIDGE,TN 37831.
C3 University of Washington; University of Washington Seattle; United States Department of Energy (DOE); Oak Ridge National Laboratory; University of Tennessee System; University of Tennessee Knoxville
RP YEH, E (corresponding author), UNIV N CAROLINA,DEPT BIOL,CHAPEL HILL,NC 27599, USA.
NR 11
TC 78
Z9 80
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 713
EP 715
DI 10.1038/349713a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700053
PM 1825352
DA 2026-03-10
ER

PT J
AU PETERS, PJ
   NEEFJES, JJ
   OORSCHOT, V
   PLOEGH, HL
   GEUZE, HJ
AF PETERS, PJ
   NEEFJES, JJ
   OORSCHOT, V
   PLOEGH, HL
   GEUZE, HJ
TI SEGREGATION OF MHC CLASS-II MOLECULES FROM MHC CLASS-I MOLECULES IN THE GOLGI-COMPLEX FOR TRANSPORT TO LYSOSOMAL COMPARTMENTS
SO NATURE
LA English
DT Article
ID mannose 6-phosphate; receptors; antigen; chains; cells; pathways; asialoglycoprotein; biosynthesis; hepatocytes; endocytosis
AB Traffic of MHC molecules dictates the source of peptides that are presented to T cells. The intracellular distribution of MHC class I and class II molecules reflects the dichotomy in presentation of antigen from endogenous and exogenous origin, respectively. In human B lymphoblastoid cells, class I molecules are present in compartments constituting the biosynthetic pathway, whereas class II molecules enter structures related to lysosomes during their biosynthesis.
C1 NETHERLANDS CANC INST, DEPT CELLULAR BIOCHEM, 1066 CX AMSTERDAM, NETHERLANDS.
C3 Netherlands Cancer Institute
RP PETERS, PJ (corresponding author), STATE UNIV UTRECHT, SCH MED, CELL BIOL LAB, HEIDELBERGLAAN 100, 3584 CX UTRECHT, NETHERLANDS.
NR 51
TC 632
Z9 670
U1 0
U2 14
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD FEB 21
PY 1991
VL 349
IS 6311
BP 669
EP 676
DI 10.1038/349669a0
PG 8
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EY627
UT WOS:A1991EY62700038
PM 1847504
DA 2026-03-10
ER

PT J
AU WILLIAMS, DA
   RIOS, M
   STEPHENS, C
   PATEL, VP
AF WILLIAMS, DA
   RIOS, M
   STEPHENS, C
   PATEL, VP
TI FIBRONECTIN AND VLA-4 IN HEMATOPOIETIC STEM-CELL MICROENVIRONMENT INTERACTIONS
SO NATURE
LA English
DT Article
ID human-plasma fibronectin; bone-marrow; growth-factor; precursor cells; adherent cells; adhesion; proliferation; identification; hematopoiesis; receptor
AB THE self-renewal and differentiation of haematopoietic stem cells occurs in vivo and in vitro in direct contact with cells making up the haematopoietic microenvironment 1-4. In this study we used adhesive ligands and blocking antibodies to identify stromal cell-derived extracellular matrix proteins involved in promoting attachment of murine haematopoietic stem cells. Here we report that day-12 colony-forming-unit spleen (CFU-S12) 5 cells and reconstituting haematopoietic stem cells attach to the C-terminal, heparin-binding fragment of fibronectin by recognizing the CS-1 peptide of the alternatively spliced non-type III connecting segment (IIICS) of human plasma fibronectin. Furthermore, CFU-S12 stem cells express the alpha-4 subunit of the VLA-4 integrin receptor, which is known to be a receptor for the CS-1 sequence, and monoclonal antibodies against the integrin alpha-4 subunit of VLA-4 block adhesion of CFU-S12 stem cells to plates coated with the C-terminal fibronectin fragment. Finally, polyclonal antibodies against the integrin beta-1 subunit of VLA-4 inhibit the formation of CFU-S12-derived spleen colonies and medullary haematopoiesis in vivo following intravenous infusion of antibody-treated bone marrow cells.
C1 HARVARD UNIV, SCH MED, HOWARD HUGHES MED INST, BOSTON, MA 02115 USA.
   HARVARD UNIV, CHILDRENS HOSP, SCH MED, DANA FARBER CANC INST, BOSTON, MA 02115 USA.
C3 Howard Hughes Medical Institute; Harvard University; Harvard Medical School; Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Dana-Farber Cancer Institute; Harvard Medical School
NR 34
TC 458
Z9 501
U1 0
U2 15
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 438
EP 441
DI 10.1038/352438a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600068
PM 1861722
DA 2026-03-10
ER

PT J
AU KRAMER, GJ
   VANBEEST, BWH
   VANSANTEN, RA
AF KRAMER, GJ
   VANBEEST, BWH
   VANSANTEN, RA
TI RELATION BETWEEN CRYSTAL SYMMETRY AND IONICITY IN SILICA POLYMORPHS
SO NATURE
LA English
DT Article
ID mechanical potential surfaces; molecular-sieve; phase transformation; intermediate phase; quartz; temperature; transition; dynamics; vpi-5
AB THE structure and stability of an inorganic solid is determined in general both by short-range covalent and by long-range electrostatic forces.  Here we describe the use of interatomic force fields developed recently from first-principles quantum-chemical cluster calculations 1, 2 in the study of the structures of SiO2 tetrahedral networks.  We find that the symmetry of these structures depends sensitively on the balance between ionic and covalent forces:  high-symmetry structures are stabilized for relatively large ion partial charges, and low-symmetry structures are stabilized when the ionicity is small.  For some SiO2 polymorphs, the low-symmetry structures found in our simulations correspond to the low-temperature phases of these polymorphs found experimentally.  A reinterpretation of structural data on quartz provides evidence for temperature dependence of the ionicity, which can explain the change of symmetry observed when temperature is increased.  Our preliminary calculations on aluminophosphates suggest that this symmetry-breaking mechanism may also provide insight into the structural changes observed for complex molecular sieves.
C1 EINDHOVEN UNIV TECHNOL,SCHUIT INST CATALYSIS,INORGAN CHEM & CATALYSIS LAB,5600 MB EINDHOVEN,NETHERLANDS.
C3 Eindhoven University of Technology
RP KRAMER, GJ (corresponding author), SHELL INT RES MAATSCHAPPIJ BV,KONINKLIJKE SHELL LAB,POB 3003,1003 AA AMSTERDAM,NETHERLANDS.
NR 26
TC 16
Z9 17
U1 1
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUN 20
PY 1991
VL 351
IS 6328
BP 636
EP 638
DI 10.1038/351636a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FT112
UT WOS:A1991FT11200059
DA 2026-03-10
ER

PT J
AU BATCHELOR, JD
   SEARS, DWG
AF BATCHELOR, JD
   SEARS, DWG
TI METAMORPHISM OF EUCRITE METEORITES STUDIED QUANTITATIVELY USING INDUCED THERMOLUMINESCENCE
SO NATURE
LA English
DT Article
ID parent body; achondrites; chondrites; evolution; history
AB EUCRITE meteorites 1 are especially important in studies of the early Solar Systems because they are the simplest and most ancient products of a process that was widespread in the inner Solar System 2,3:  basaltic volcanism.  They are also the meteorites for which there is least doubt of an asteroidal origin 4,5.  After volcanism the eucrites experienced a period of metamorphism 6, either inside the asteroid as it cooled from igneous temperatures 7 or on the surface of the asteroid as a result of impact heating 8.  Induced thermoluminescence studies provide a new and quantitative means of determining relative metamorphic intensities for these meteorites.  Using this technique, we show that the eucrites constitute a continuous metamorphic series and not, as commonly assumed, two groups of metamorphosed and non-metamorphosed meteorites 9.  These studies are the first application of the induced thermoluminescence technique to igneous rocks and we suggest that the method may well have application to other basalts.
RP BATCHELOR, JD (corresponding author), UNIV ARKANSAS,DEPT CHEM & BIOCHEM,COSMOCHEM GRP,FAYETTEVILLE,AR 72701, USA.
NR 36
TC 15
Z9 15
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 516
EP 518
DI 10.1038/349516a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100063
DA 2026-03-10
ER

PT J
AU SANCHEZLAVEGA, A
   COLAS, F
   LECACHEUX, J
   LAQUES, P
   MIYAZAKI, I
   PARKER, D
AF SANCHEZLAVEGA, A
   COLAS, F
   LECACHEUX, J
   LAQUES, P
   MIYAZAKI, I
   PARKER, D
TI THE GREAT WHITE SPOT AND DISTURBANCES IN SATURNS EQUATORIAL ATMOSPHERE DURING 1990
SO NATURE
LA English
DT Article
ID voyager infrared measurements; northern hemisphere; encounter; images; model
AB A giant storm, the Great White Spot, erupted at the end of September 1990 as a localized, bright cloud system close to Saturn's equator. Its evolution produced a complex planetary disturbance which affected the whole equatorial region a month later. Similar spots have appeared approximately once every saturnian year (about 30 Earth years), implying that a seasonal change-in solar heating, for example-may be responsible for their occurrence.
C1 UNIV BASQUE COUNTRY, ESCUELA TECN SUPER INGN IND & TELECOMMUN, DEPT FIS APLICADA 1, E-48013 BILBAO, SPAIN.
   BUR LONGITUDES, F-75014 PARIS, FRANCE.
   OBSERV MEUDON, DESPA, F-92195 MEUDON, FRANCE.
   OBSERV PIC DU MIDI, F-65200 BAGNERES DE BIGORRE, FRANCE.
   INST PLANETARY RES OBSERV, MIAMI, FL USA.
C3 University of Basque Country; Universite PSL; Observatoire de Paris
NR 21
TC 81
Z9 84
U1 0
U2 6
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 397
EP 401
DI 10.1038/353397a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600046
DA 2026-03-10
ER

PT J
AU ACSADI, G
   DICKSON, G
   LOVE, DR
   JANI, A
   WALSH, FS
   GURUSINGHE, A
   WOLFF, JA
   DAVIES, KE
AF ACSADI, G
   DICKSON, G
   LOVE, DR
   JANI, A
   WALSH, FS
   GURUSINGHE, A
   WOLFF, JA
   DAVIES, KE
TI HUMAN DYSTROPHIN EXPRESSION IN MDX MICE AFTER INTRAMUSCULAR INJECTION OF DNA CONSTRUCTS
SO NATURE
LA English
DT Article
ID muscle; mouse; invivo; transfection; myopathy; protein; repeat
AB DUCHENNE'S muscular dystrophy (DMD), which affects one in 3,500 males, causes progressive myopathy of skeletal and cardiac muscles and premature death 1.  One approach to treatment would be to introduce the normal dystrophin gene into diseased muscle cells.  When pure plasmid DNA is injected into rodent skeletal 2 or cardiac muscle 3-5, the cells express reporter genes.  We now show that a 12-kilobase full-length human dystrophin complementary DNA gene and a 6.3-kilobase Becker-like gene 6 can be expressed in cultured cells and in vivo.  When the human dystrophin expression plasmids are injected intramuscularly into dystrophin-deficient mdx mice, the human dystrophin proteins are present in the cytoplasm and sarcolemma of approximately 1% of the myofibres.  Myofibres expressing human dystrophin contain an increased proportion of peripheral nuclei.  The results indicate that transfer of the dystrophin gene into the myofibres of DMD patients could be beneficial, but a larger number of genetically modified myofibres will be necessary for clinical efficacy.
C1 UNIV WISCONSIN,WAISMAN CTR MENTAL RETARDAT & HUMAN DEV,DEPT PEDIAT,MADISON,WI 53706.
   UNIV WISCONSIN,WAISMAN CTR MENTAL RETARDAT & HUMAN DEV,DEPT MED GENET,MADISON,WI 53706.
   UNITED MED & DENT SCH GUYS & ST THOMAS HOSP,GUYS HOSP,DEPT EXPTL PATHOL,LONDON SE1 9RT,ENGLAND.
   JOHN RADCLIFFE HOSP,INST MOLEC MED,MOLEC GENET GRP,OXFORD OX3 9DU,ENGLAND.
C3 University of Wisconsin System; University of Wisconsin Madison; University of Wisconsin System; University of Wisconsin Madison; University of London; King's College London; Guy's & St Thomas' NHS Foundation Trust; University of Oxford
NR 30
TC 398
Z9 533
U1 0
U2 16
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 29
PY 1991
VL 352
IS 6338
BP 815
EP 818
DI 10.1038/352815a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GC964
UT WOS:A1991GC96400064
PM 1881437
DA 2026-03-10
ER

PT J
AU JAHN, M
   ROGERS, MJ
   SOLL, D
AF JAHN, M
   ROGERS, MJ
   SOLL, D
TI ANTICODON AND ACCEPTOR STEM NUCLEOTIDES IN TRANSFER RNAGLN ARE MAJOR RECOGNITION ELEMENTS FOR ESCHERICHIA-COLI GLUTAMINYL-TRANSFER RNA-SYNTHETASE
SO NATURE
LA English
DT Article
ID identity; aminoacylation; methionine; invitro; specificity; parameters; invivo; gln
AB THE correct attachment of amino acids to their corresponding (cognate) transfer RNA catalysed by aminoacyl-tRNA synthetases is a key factor in ensuring the fidelity of protein biosynthesis. Previous studies have demonstrated that the interaction of Escherichia coli tRNA(Gln) with glutaminyl-tRNA synthetase (GlnRS) provides an excellent system 1 to study this highly specific recognition process, also referred to as 'tRNA identity' 2.  Accurate acylation of tRNA depends mainly on two principles: a set of nucleotides in the tRNA molecule (identity elements) responsible for proper discrimination by aminoacyl-tRNA synthetases 1-3  and competition between different synthetases for tRNAs 4-6. Elements of glutamine identity are located in the anticodon 2,7-9 and in the acceptor stem region, including the discriminator base 5,10-13. We report here the production of more than 20 tRNA2Gln mutants at positions likely to be involved in tRNA discrimination by the enzyme. Unmodified tRNA, containing the wild-type anticodon and U or G at its 5'-terminus, can be aminocylated by GlnRS with similar kinetic parameters to native tRNA2Gln. By in vitro aminoacylation the mutant tRNAs showed decreases of up to 3 x 10(5)-fold in the specificity constant (k(cat)/K(M)) 14 with the major contribution of k(cat). Despite these large changes, some of these mutant tRNAs are efficient amber suppressors in vivo. Our results show that strong elements for glutamine identity reside in the anticodon region and in positions 2 and 3 of the acceptor stem, and that the contribution of different identity elements to the overall discrimination varies significantly. We discuss our data in the light of the crystal structure of the GlnRS:tRNA(Gln) complex 15,16.
C1 YALE UNIV,DEPT MOLEC BIOPHYS & BIOCHEM,NEW HAVEN,CT 06511.
C3 Yale University
NR 35
TC 198
Z9 219
U1 0
U2 9
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 258
EP 260
DI 10.1038/352258a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500072
PM 1857423
DA 2026-03-10
ER

PT J
AU MAHOWALD, M
   DOUGLAS, R
AF MAHOWALD, M
   DOUGLAS, R
TI A SILICON NEURON
SO NATURE
LA English
DT Article
AB BY combining neurophysiological principles with silicon engineering, we have produced an analog integrated circuit with the functional characteristics of real nerve cells. Because the physics underlying the conductivity of silicon devices and biological membranes is similar, the 'silicon neuron' is able to emulate efficiently the ion currents that cause nerve impulses and control the dynamics of their discharge. It operates in real-time and consumes little power, and many 'neurons' can be fabricated on a single silicon chip. The silicon neuron represents a step towards constructing artificial nervous systems that use more realistic principles of neural computation than do existing electronic neural networks.
C1 UNIV OXFORD,MRC,ANAT NEUROPHARMACOL UNIT,OXFORD OX1 3TH,ENGLAND.
   CALTECH,COMPUTAT & NEURAL SYST LAB,PASADENA,CA 91125.
   UNIV CAPE TOWN,DEPT PHYSIOL,CAPE TOWN 7925,SOUTH AFRICA.
C3 University of Oxford; California Institute of Technology; University of Cape Town
NR 7
TC 352
Z9 387
U1 1
U2 70
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 19
PY 1991
VL 354
IS 6354
BP 515
EP 518
DI 10.1038/354515a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GW751
UT WOS:A1991GW75100011
PM 1661852
DA 2026-03-10
ER

PT J
AU BONNEAU, PR
   JARVIS, RF
   KANER, RB
AF BONNEAU, PR
   JARVIS, RF
   KANER, RB
TI RAPID SOLID-STATE SYNTHESIS OF MATERIALS FROM MOLYBDENUM-DISULFIDE TO REFRACTORIES
SO NATURE
LA English
DT Article
ID transition-metal sulfides; hydrodesulfurization catalysts; chalcogenides
AB LAYERED molybdenum and tungsten dichalcogenides have stimulated considerable interest as lubricants 1,2, battery cathodes 3-5, and catalysts 6-8.  Pure, crystalline group VI transition-metal dichalcogenides are normally prepared by intermittently grinding and heating the elements at > 900-degrees-C for several days. Low-temperature solution routes to these materials have also been explored 9-11.  In those studies, exchange (metathesis) reactions between transition-metal halides and alkali-metal sulphides or covalent sulphiding agents in polar organic solvents were found generally to yield finely divided products at close to ambient conditions.  Here, in contrast, we consider the factors that influence reactions between transition-meta halides and alkali-metal chalcogenides in the solid state.  These highly energetic reactions, driven by the formation of very stable product species, provide a powerful method for the rapid synthesis of materials normally prepared at high temperatures over long periods of time.  Other advantages of these solid-state reactions include control of reaction conditions and of product particle sizes. Although our study focuses on group VI transition-metal dichalcogenides, analogous metathesis reactions can be used for rapid syntheses, initiated at low temperatures, of many other technologically important materials.
C1 UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024.
   UNIV CALIF LOS ANGELES,CTR SOLID STATE SCI,LOS ANGELES,CA 90024.
C3 University of California System; University of California Los Angeles; University of California System; University of California Los Angeles
NR 16
TC 234
Z9 255
U1 0
U2 126
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 7
PY 1991
VL 349
IS 6309
BP 510
EP 512
DI 10.1038/349510a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EW571
UT WOS:A1991EW57100061
DA 2026-03-10
ER

PT J
AU PETERSON, MG
   INOSTROZA, J
   MAXON, ME
   FLORES, O
   ADMON, A
   REINBERG, D
   TJIAN, R
AF PETERSON, MG
   INOSTROZA, J
   MAXON, ME
   FLORES, O
   ADMON, A
   REINBERG, D
   TJIAN, R
TI STRUCTURE AND FUNCTIONAL-PROPERTIES OF HUMAN GENERAL TRANSCRIPTION FACTOR-IIE
SO NATURE
LA English
DT Article
ID rna polymerase-ii; binding-protein; purification; initiation; activation; sequences; cells
AB The general transcription factor IIE (TFIIE) is an essential component of the eukaryotic RNA polymerase 11 initiation complex. We have isolated human complementary DNA clones for both the subunits of TFIIE. Using purified recombinant proteins we find that both subunits are essential to form a stable preinitiation complex and to reconstitute basal-level and Sp1-activated transcription in vitro. Analysis of their predicted amino-acid sequences reveals several intriguing structural motifs that could provide insight into the role of TFIIE in transcription initiation.
C1 UNIV MED & DENT NEW JERSEY,ROBERT WOOD JOHNSON MED SCH,PISCATAWAY,NJ 08854.
C3 Rutgers University System; Rutgers University New Brunswick; Rutgers University Biomedical & Health Sciences
RP PETERSON, MG (corresponding author), UNIV CALIF BERKELEY,HOWARD HUGHES MED INST,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720, USA.
NR 26
TC 183
Z9 196
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 369
EP 373
DI 
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100042
PM 1956398
DA 2026-03-10
ER

PT J
AU EWBANK, JJ
   CREIGHTON, TE
AF EWBANK, JJ
   CREIGHTON, TE
TI THE MOLTEN GLOBULE PROTEIN CONFORMATION PROBED BY DISULFIDE BONDS
SO NATURE
LA English
DT Article
ID alpha-lactalbumin; state
AB THE molten globule is a compact protein conformation that has a secondary structure content like that of the native protein, but poorly defined tertiary structure. It is a stable state for a few proteins under particular conditions 1 and could be a ubiquitous kinetic intermediate in protein folding 2. The extent to which native interactions, above the level of the secondary structure, are preserved in this conformation is not so far known. Here we report that alpha-lactalbumin can adopt a molten globule conformation when one of its four disulphide bonds is reduced. In this state, the three other disulphide bonds rearrange spontaneously, at the same rate as when the protein is fully unfolded, to a number of different disulphide bond isomers that tend to maintain the molten globule conformation. That the molten globule state is compatible with a variety of disulphide bond pairings suggests that it is unlikely to be stabilized by many specific tertiary interactions.
C1 MRC, MOLEC BIOL LAB, CAMBRIDGE CB2 2QH, ENGLAND.
C3 MRC Laboratory Molecular Biology
NR 18
TC 141
Z9 146
U1 2
U2 15
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD APR 11
PY 1991
VL 350
IS 6318
BP 518
EP 520
DI 10.1038/350518a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FG143
UT WOS:A1991FG14300057
PM 1901628
DA 2026-03-10
ER

PT J
AU BUESSELER, KO
AF BUESSELER, KO
TI DO UPPER-OCEAN SEDIMENT TRAPS PROVIDE AN ACCURATE RECORD OF PARTICLE-FLUX
SO NATURE
LA English
DT Article
ID particulate organic-carbon; upper water column; northeast pacific; nitrogen; th-234; disequilibria; efficiency
AB SEDIMENT traps are widely used to measure the vertical flux of particulate matter in the oceans.  In the upper ocean, sediment traps have been used to determine the extent to which CO2 fixed by primary producers is exported as particulate organic carbon 1-3.  In addition, the observed decrease of particle flux with depth has been used to predict regeneration rates of organic matter and associated elements 3.  Over seasonal or annual timescales, the import of limiting nutrients into the upper ocean (new production) should be balanced by particle export 4,5.  Given the importance of accurately determining the sinking particle flux, it has been suggested that Th-234 might be used to 'calibrate' shallow-trap fluxes 6.  Here I present a re-evaluation of existing Th-234 data which indicates that trap-derived and model-derived Th-234 particle fluxes can differ by a factor of +/- 3-10, suggesting that shallow traps may not provide an accurate measure of particle fluxes.
RP BUESSELER, KO (corresponding author), WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543, USA.
NR 32
TC 270
Z9 290
U1 0
U2 47
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 420
EP 423
DI 10.1038/353420a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600053
DA 2026-03-10
ER

PT J
AU KELLY, KK
   TUCK, AF
   DAVIES, T
AF KELLY, KK
   TUCK, AF
   DAVIES, T
TI WINTERTIME ASYMMETRY OF UPPER TROPOSPHERIC WATER BETWEEN THE NORTHERN AND SOUTHERN HEMISPHERES
SO NATURE
LA English
DT Article
ID evolution; climate; vapor; ozone; co2
AB WATER vapour is an important greenhouse gas 1-3 and yet its abundance in the upper troposphere is poorly known. Upper-tropospheric water vapour is particularly important despite its low mixing ratios, because it has large effects on the flux of infrared radiation near the tropopause 2.  In addition, the distribution and supply of water vapour are central to cloud formation; the effects of cloud on the Earth's radiation budget are in turn central to understanding the climate response to increasing atmospheric concentrations of greenhouse gases. From airborne measurements of total water (vapour plus ice crystal) 4 during the winters of 1987 in the Southern Hemisphere and of 1988-89 in the Northern Hemisphere, we find that the upper troposphere in middle, subpolar and high latitudes is a factor of 2-4 drier during austral winter than during boreal winter. As the lower-latitude air moves towards the pole in austral winter, it is forced to cool to lower temperatures than in the north-more of the water vapour therefore condenses to form ice crystals, which then precipitate, thereby removing moisture from the air mass. Clearly, climate models must be able to reproduce this asymmetry if their predictions are to be credible. We also note that the asymmetry in water vapour implies an asymmetry in the production rate of the hydroxyl radical, and hence in the tropospheric chemistry of each hemisphere, for example in the rate of methane loss 5.
C1 EUROPEAN CTR MEDIUM RANGE WEATHER FORECASTS,READING,BERKS,ENGLAND.
C3 European Centre for Medium-Range Weather Forecasts (ECMWF)
RP KELLY, KK (corresponding author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA.
NR 20
TC 49
Z9 53
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 19
PY 1991
VL 353
IS 6341
BP 244
EP 247
DI 10.1038/353244a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GF674
UT WOS:A1991GF67400054
DA 2026-03-10
ER

PT J
AU PULVERER, BJ
   KYRIAKIS, JM
   AVRUCH, J
   NIKOLAKAKI, E
   WOODGETT, JR
AF PULVERER, BJ
   KYRIAKIS, JM
   AVRUCH, J
   NIKOLAKAKI, E
   WOODGETT, JR
TI PHOSPHORYLATION OF C-JUN MEDIATED BY MAP KINASES
SO NATURE
LA English
DT Article
ID v-jun; protein; ap-1; transcription; activation; encodes
AB THE proto-oncogene c-jun is a component of the AP-1 transcription factor family involved in the mediation of nuclear events elicited by extracellular stimuli 1-3. The c-jun protein is negatively regulated by phosphorylation of residues near the carboxy terminus which are dephosphorylated in response to phorbol esters 4. Here we identify two serine residues in the amino terminal A1 transactivation domain which are phosphorylated in response to a variety of mitogens, phorbol esters and activated ras (ref. 5). We present evidence that mitogen-activated protein-serine (MAP) kinases (pp54 and pp42/44) specifically phosphorylate these sites and that their phosphorylation positively regulates the transacting activity of c-jun. The MAP kinase enzymes pp54 and pp42/44 are regulated by tyrosine as well as serine/threonine phosphorylation 6,7.  MAP kinase activation of c-jun may underlie the common stimulation of this transcription factor by mitogens, growth factors and oncogenes.
C1 LUDWIG INST CANC RES,91 RIDING HOUSE ST,LONDON W1P 8BT,ENGLAND.
   HARVARD UNIV,SCH MED,DEPT MED,BOSTON,MA 02115.
   MASSACHUSETTS GEN HOSP,DIABET UNIT,BOSTON,MA 02114.
   MASSACHUSETTS GEN HOSP,MED SERV,BOSTON,MA 02114.
C3 Ludwig Institute for Cancer Research; Harvard University; Harvard Medical School; Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital
NR 20
TC 1437
Z9 1584
U1 0
U2 22
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 17
PY 1991
VL 353
IS 6345
BP 670
EP 674
DI 10.1038/353670a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GK672
UT WOS:A1991GK67200075
PM 1922387
DA 2026-03-10
ER

PT J
AU CHAIZY, P
   REME, H
   SAUVAUD, JA
   DUSTON, C
   LIN, RP
   LARSON, DE
   MITCHELL, DL
   ANDERSON, KA
   CARLSON, CW
   KORTH, A
   MENDIS, DA
AF CHAIZY, P
   REME, H
   SAUVAUD, JA
   DUSTON, C
   LIN, RP
   LARSON, DE
   MITCHELL, DL
   ANDERSON, KA
   CARLSON, CW
   KORTH, A
   MENDIS, DA
TI NEGATIVE-IONS IN THE COMA OF COMET HALLEY
SO NATURE
LA English
DT Article
ID solar-wind interaction; giotto magnetometer experiment; electron measurements; photo-dissociation; bow shock; p-halley; plasma; region; photodetachment; p/halley
AB IN March 1986, the Giotto spacecraft encountered comet Halley, approaching to within approximately 600 km of the nucleus.  Results from this encounter have shown that the inner coma contains a mixture of cometary neutral gas and dust, thermal ions and electrons, fast cometary pick-up ions, and decelerated solar-wind ions and electrons, as well as fast neutrals 1 produced by charge exchange between pick-up ions and cold neutrals.  Here we report the detection of a new component of the inner coma of comet Halley:  negatively charged cometary ions.  These ions are observed in three broad mass peaks at 7-19, 22-65 and 85-110 AMU, with densities reaching greater-than-or-similar-to 1, approximately 5 x 10(-2) and approximately 4 x 10(-2) cm(-3), respectively, at a distance of approximately 2,300 km from the nucleus.  The ion species thought to be present include O-, OH-, C-, CH-, CN- and heavier complex CHO molecular ions.  As negative ions are easily destroyed by solar by solar radiation at approximately 1 AU (ref. 2) an efficient production mechanism, so far unidentified, is required to account for the observed densities.  The detection of negative ions in the coma near 1 AU implies that in similar neutral gas and dust environments farther away from the Sun (in Jupiter's or Saturn's magnetospheres 3, for example), negative ions should also be present.  If the negative-ion densities are large enough, they could play an important part in physical processes such as radiative transfer or charge exchange.
C1 MAX PLANCK INST AERON,W-3411 KATLENBURG-DUHM,GERMANY.
   UNIV CALIF SAN DIEGO,DEPT ELECT ENGN & COMP SCI,LA JOLLA,CA 92093.
   UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720.
C3 Max Planck Society; University of California System; University of California San Diego; University of California System; University of California Berkeley
RP CHAIZY, P (corresponding author), CTR ETUD SPATIALE RAYONNEMENTS,9 AVE COLONEL,BP 4346,F-31029 TOULOUSE,FRANCE.
NR 26
TC 225
Z9 232
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 393
EP 396
DI 10.1038/349393a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400041
DA 2026-03-10
ER

PT J
AU GYOEVA, FK
   GELFAND, VI
AF GYOEVA, FK
   GELFAND, VI
TI COALIGNMENT OF VIMENTIN INTERMEDIATE FILAMENTS WITH MICROTUBULES DEPENDS ON KINESIN
SO NATURE
LA English
DT Article
ID monoclonal-antibody; micro-injection; collapse; cells; movement; tubulin
AB INTERMEDIATE filaments in most types of cultured cells coalign with microtubules.  Depolymerization of microtubules results in collapse of vimentin and desmin intermediate filaments to the nucleus where they form a perinuclear cap (reviewed in ref. 1).  Collapse can also be induced by microinjection of antibodies against intermediate filament or microtubule proteins 2-7.  Thus, two filament systems interact with each other.  But the molecules mediating this interaction are unknown.  One of the candidates for this role is a microtubule motor kinesin 8.  Recent data showed that kinesin is involved in the plus end-directed movement of the membranous organelles along microtubules such as radial extension of lysosomes in macrophages 9 and centrifugal movement of pigment in melanophores 10.  Here we report that injection of the anti-kinesin antibody into human fibroblasts results in the redistribution of intermediate filaments to a tight perinuclear aggregate but had no effect on the distribution of microtubules.  Thus, kinesin is involved not only in organelle movement but also in interaction of the two major cytoskeletal systems, intermediate filaments and microtubules.
C1 ACAD SCI USSR,INST PROT RES,PUSHCHINO 142292,USSR.
C3 Russian Academy of Sciences
NR 20
TC 212
Z9 229
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD OCT 3
PY 1991
VL 353
IS 6343
BP 445
EP 448
DI 10.1038/353445a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GH606
UT WOS:A1991GH60600062
PM 1832745
DA 2026-03-10
ER

PT J
AU AHRINGER, J
   KIMBLE, J
AF AHRINGER, J
   KIMBLE, J
TI CONTROL OF THE SPERM-OOCYTE SWITCH IN CAENORHABDITIS-ELEGANS HERMAPHRODITES BY THE FEM-3 3' UNTRANSLATED REGION
SO NATURE
LA English
DT Article
ID sex-determination gene; c-elegans; spermatogenesis; sequences
AB IN the Caenorhabditis elegans hermaphrodite germ line, sperm and then oocytes are made from a common pool of germ-cell precursors. The decision to differentiate as a sperm or an oocyte is regulated by the sex-determining gene, fem-3. Expression of fem-3 in the hermaphrodite germ line directs spermatogenesis and must be negatively regulated to allow the switch to oogenesis1,2. In adult hermaphrodites (which are producing oocytes), most fem-3 RNA is found in the germ line3, consistent with both the requirement for fem-3 in hermaphrodite spermatogenesis and the maternal effects of fem-3 on embryonic sex determination1,2. Whereas loss-of-function mutants in fem-3 produce only oocytes, hermaphrodites carrying any of nine fem-3 gain-of-function (gf) mutations make none; instead sperm are produced continuously and in vast excess over wild-type amounts1. Genetic analyses suggest that fem-3(gf) mutations have escaped a negative control required for the switch to oogenesis1. Here we report that all nine fem-3(gf) mutants carry sequence alterations in the fem-3 3' untranslated region (3' UTR). There is no increase in the steady-state level of fem-3(gf) RNA over wild-type, but there is an increase in the polyadenylation of fem-3(gf) RNA that is coincident with the unregulated fem-3 activity. Results of a titration experiment support the hypothesis that a regulatory factory may bind the fem-3 3' UTR. We speculate that fem-3 RNA is regulated through its 3' UTR by binding a factor that inhibits translation, and discuss the idea that this control may be part of a more general regulation of maternal RNAs.
C1 UNIV WISCONSIN, GRAD SCH, MOLEC BIOL LAB, 1525 LINDEN DR, MADISON, WI 53706 USA.
   UNIV WISCONSIN, COLL AGR & LIFE SCI, DEPT BIOCHEM, MADISON, WI 53706 USA.
C3 University of Wisconsin System; University of Wisconsin Madison; University of Wisconsin System; University of Wisconsin Madison
NR 16
TC 202
Z9 239
U1 0
U2 6
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JAN 24
PY 1991
VL 349
IS 6307
BP 346
EP 348
DI 10.1038/349346a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EU501
UT WOS:A1991EU50100058
PM 1702880
DA 2026-03-10
ER

PT J
AU RAM, M
   GAYLEY, RI
AF RAM, M
   GAYLEY, RI
TI LONG-RANGE TRANSPORT OF VOLCANIC ASH TO THE GREENLAND ICE-SHEET
SO NATURE
LA English
DT Article
ID past volcanism; age
AB BETZER et al. 1 reported the surprising discovery of 'giant' (> 75 mu-m) mineral particles transported more than 10,000 km from their source.  We have found volcanic ash containing glass shards as large as 300-mu-m in a section of Wisconsinian ice from the Dye 3 core in Greenland, which is similarly unexpected and raises interesting questions concerning the long-range aeolian transport of particulate matter.  As the volcanic ash correlates well with similar ash in deep-sea sediment cores from the Atlantic, it also allows us to date the ice with some confidence.
RP RAM, M (corresponding author), SUNY BUFFALO,DEPT PHYS,FRONCZAK HALL,BUFFALO,NY 14260, USA.
NR 21
TC 38
Z9 40
U1 0
U2 2
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 31
PY 1991
VL 349
IS 6308
BP 401
EP 404
DI 10.1038/349401a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EV514
UT WOS:A1991EV51400045
DA 2026-03-10
ER

PT J
AU WATANABE, N
   HUNT, T
   IKAWA, Y
   SAGATA, N
AF WATANABE, N
   HUNT, T
   IKAWA, Y
   SAGATA, N
TI INDEPENDENT INACTIVATION OF MPF AND CYTOSTATIC FACTOR (MOS) UPON FERTILIZATION OF XENOPUS EGGS
SO NATURE
LA English
DT Article
ID maturation-promoting factor; proto-oncogene product; cell-cycle; oocytes; arrest; metaphase; component
AB IN vertebrates, mature eggs are arrested at the second meiotic metaphase by the cytostatic factor (CSF) 1, now known to be the c-mos proto-oncogene product (Mos) 2,3. Fertilization or egg activation triggers a transient increase in the cytoplasmic free calcium 4,5 and releases the meiotic arrest by inactivating maturation/mitosis-promoting factor (MPF) 6,7.   CSF or Mos, which is also inactivated by the calcium transient 8,9, seems to stabilize MPF in mature eggs and CSF-injected embryos. Thus, it was assumed that CSF inactivation is the primary cause of MPF inactivation on meiotic release 2,6,8,10-14. We have directly compared the degradation kinetics of CSF (Mos) and MPF during meiotic release, using the same batch of Xenopus eggs. We report here that, at the molecular level, cyclin subunits of MPF are degraded before Mos is degraded and, at the physiological level, that MPF activity is inactivated before CSF activity during activation of Xenopus eggs. These results, in conjunction with circumstantial evidence, support the novel view that a calcium transient on fertilization induces a CSF-independent pathway for MPF inactivation, whereas CSF inactivation during meiotic release serves only to allow the fertilized egg to enter mitosis.
C1 KURUME UNIV,INST LIFE SCI,DIV MOLEC GENET,2432-3 AIKAWA,KURUME,FUKUOKA 830,JAPAN.
   INST PHYS & CHEM RES,TSUKUBA LIFE SCI CTR,TSUKUBA,IBARAKI 305,JAPAN.
   IMPERIAL CANC RES FUND,CLARE HALL LABS,S MIMMS EN6 3LD,HERTS,ENGLAND.
   TOKYO MED & DENT UNIV,BUNKYO KU,TOKYO 113,JAPAN.
C3 Kurume University; RIKEN; Institute of Science Tokyo; Tokyo Medical & Dental University (TMDU)
NR 24
TC 162
Z9 168
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 18
PY 1991
VL 352
IS 6332
BP 247
EP 248
DI 10.1038/352247a0
PG 2
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FX185
UT WOS:A1991FX18500068
PM 1830371
DA 2026-03-10
ER

PT J
AU ADAMS, AEM
   BOTSTEIN, D
   DRUBIN, DG
AF ADAMS, AEM
   BOTSTEIN, D
   DRUBIN, DG
TI REQUIREMENT OF YEAST FIMBRIN FOR ACTIN ORGANIZATION AND MORPHOGENESIS INVIVO
SO NATURE
LA English
DT Article
AB THE SAC6 gene was found by suppression of a yeast actin mutation 1. Its protein product, Sac6p (previously referred to as ABP67), was independently isolated by actin-filament affinity chromatography and colocalizes with actin in vivo 2. Thus Sac6p binds to actin in vitro, and functionally associates with actin structures involved in the development and maintenance of cell polarity in vivo 2,3. We report here that Sac6p is an actin-filament bundling protein 43% identical in amino-acid sequence to the vertebrate bundling protein fimbrin 4. This yeast fimbrin homologue contains two putative actin-binding regions 5 homologous to domains of dystrophin, beta-spectrin, filamin, actin-gelation protein and alpha-actinin. Mutants lacking Sac6p do not form normal actin structures and are defective in morphogenesis. These findings demonstrate an in vivo role for the well-documented biochemical interaction between fimbrin and actin.
C1 STANFORD UNIV, MED CTR, SCH MED, DEPT GENET, STANFORD, CA 94305 USA.
   UNIV CALIF BERKELEY, DEPT MOLEC & CELL BIOL, BERKELEY, CA 94720 USA.
C3 Stanford University; University of California System; University of California Berkeley
RP ADAMS, AEM (corresponding author), UNIV ARIZONA, DEPT MOLEC & CELLULAR BIOL, LIFE SCI S, TUCSON, AZ 85721 USA.
NR 28
TC 192
Z9 213
U1 0
U2 7
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 404
EP 408
DI 10.1038/354404a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100055
PM 1956405
DA 2026-03-10
ER

PT J
AU CHEN, CT
   TJENG, LH
   RUDOLF, P
   MEIGS, G
   ROWE, JE
   CHEN, J
   MCCAULEY, JP
   SMITH, AB
   MCGHIE, AR
   ROMANOW, WJ
   PLUMMER, EW
AF CHEN, CT
   TJENG, LH
   RUDOLF, P
   MEIGS, G
   ROWE, JE
   CHEN, J
   MCCAULEY, JP
   SMITH, AB
   MCGHIE, AR
   ROMANOW, WJ
   PLUMMER, EW
TI ELECTRONIC STATES AND PHASES OF KXC60 FROM PHOTOEMISSION AND X-RAY ABSORPTION-SPECTROSCOPY
SO NATURE
LA English
DT Article
ID cu
AB HIGH-resolution photoemission and soft X-ray absorption spectroscopies have provided valuable information on the electronic structure near the Fermi energy in the superconducting copper oxide compounds 1-4, helping to constrain the possible mechanisms of superconductivity. Here we describe the application of these techniques to K(x)C60, found recently to be superconducting below 19.3 K for x almost-equal-to 3 (refs 5-7). The photoemission and absorption spectra as a function of x can be fitted by a linear combination of data from just three phases, C60, K3C60, and K6C60, indicating that there is phase separation in our samples. The photoemission spectra clearly show a well defined Fermi edge in the K3C60 phase with a density of states of 5.2 x 10(-3) electrons eV-1 angstrom-3 and an occupied-band width of 1.2 eV, suggesting that this phase may be a weakly coupled BCS-like (conventional) superconductor. The C1s absorption spectra show large non-rigid-band shifts between the three phases with half and complete filling, in the K3C60 and K6C60 phases respectively, of the conduction band formed from the lowest unoccupied molecular orbital of C60. These observations clearly demonstrate that the conduction band has C 2p character. The non-rigid-band shift coupled with the anomalous occupied-band width implies that there is significant mixing of the electronic states of K and C60 in the superconducting phase.
C1 UNIV PENN,RES STRUCT MATTER LAB,PHILADELPHIA,PA 19104.
C3 University of Pennsylvania
RP CHEN, CT (corresponding author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA.
NR 19
TC 241
Z9 249
U1 0
U2 55
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 15
PY 1991
VL 352
IS 6336
BP 603
EP 605
DI 10.1038/352603a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GB211
UT WOS:A1991GB21100048
DA 2026-03-10
ER

PT J
AU FLUGGE, UI
   WEBER, A
   FISCHER, K
   LOTTSPEICH, F
   ECKERSKORN, C
   WAEGEMANN, K
   SOLL, J
AF FLUGGE, UI
   WEBER, A
   FISCHER, K
   LOTTSPEICH, F
   ECKERSKORN, C
   WAEGEMANN, K
   SOLL, J
TI THE MAJOR CHLOROPLAST ENVELOPE POLYPEPTIDE IS THE PHOSPHATE TRANSLOCATOR AND NOT THE PROTEIN IMPORT RECEPTOR
SO NATURE
LA English
DT Article
ID mesophyll chloroplasts; spinach-chloroplasts; contact zones; membrane; identification; outer; localization; mitochondria; transport; sequence
AB DURING photosynthetic CO2 fixation, fixed carbon is exported from the chloroplasts in the form of triose phosphate by the chloroplast phosphate translocator, which is the principal polypeptide (E29) from spinach chloroplast envelopes 1.  We have sequenced this nuclear-coded envelope membrane protein from both spinach and pea chloroplasts 2,3.  An envelope membrane protein, E30, has been identified as a possible receptor for protein import into pea chloroplasts using an anti-idiotypic antibody approach 4-6; antibodies raised against purified E30 inhibited binding and import of proteins into chloroplasts 7.  The amino-acid sequence of E30 deduced from its complementary DNA 7 turned out to be highly homologous to that of E29, assigned by us as the spinach phosphate translocator 2, and was identical to the corresponding polypeptide from pea chloroplasts 3.  Differences in the binding properties to hydroxylapatite of E30 and the phosphate translocator suggested that E30 was not responsible for the chloroplast phosphate-transport activity but was the chloroplast import receptor 7.  Here we present evidence that argues against this and which identifies E30 as the chloroplast phosphate translocator.
C1 MAX PLANCK INST BIOCHEM,W-8033 MARTINSRIED,GERMANY.
   UNIV MUNICH,INST BOT,W-8000 MUNICH 19,GERMANY.
   UNIV SAARLAND,INST BOT,W-6600 SAARBRUCKEN,GERMANY.
C3 Max Planck Society; University of Munich; Saarland University
RP FLUGGE, UI (corresponding author), UNIV WURZBURG,JULIUS VON SACHS INST BIOWISSENSCH,BOT CHEM GARTEN,W-8700 WURZBURG,GERMANY.
NR 29
TC 54
Z9 57
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 364
EP 367
DI 10.1038/353364a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400065
DA 2026-03-10
ER

PT J
AU HAGELBERG, E
   GRAY, IC
   JEFFREYS, AJ
AF HAGELBERG, E
   GRAY, IC
   JEFFREYS, AJ
TI IDENTIFICATION OF THE SKELETAL REMAINS OF A MURDER VICTIM BY DNA ANALYSIS
SO NATURE
LA English
DT Article
ID polymerase chain-reaction; dinucleotide repeat; minisatellites; polymorphisms; amplification
AB THERE is considerable anthropological and forensic interest in the possibility of DNA typing skeletal remains. Trace amounts of DNA can be recovered even from 5,500-year-old bones and multicopy human mitochondrial DNA sequences can frequently be amplified from such DNA using the polymerase chain reaction (PCR) 1,2. But given the sensitivity of PCR, it is very difficult to exclude contaminating material. We now report the successful identification of the 8-year-old skeletal remains of a murder victim, by comparative typing of nuclear microsatellite markers 3-5 in the remains and in the presumptive parents of the victim. This analysis establishes the authenticity of the bone DNA and the feasibility of bone DNA typing in forensic investigations.
C1 UNIV LEICESTER, DEPT GENET, LEICESTER LE1 7RH, ENGLAND.
C3 University of Leicester
RP HAGELBERG, E (corresponding author), UNIV OXFORD, JOHN RADCLIFFE HOSP, INST MOLEC MED, MRC, MOLEC HAEMATOL UNIT, OXFORD OX3 9DU, ENGLAND.
FU Wellcome Trust Funding Source: Medline
NR 13
TC 227
Z9 258
U1 1
U2 36
PU NATURE PORTFOLIO
PI BERLIN
PA HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD AUG 1
PY 1991
VL 352
IS 6334
BP 427
EP 429
DI 10.1038/352427a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FZ346
UT WOS:A1991FZ34600063
PM 1861721
DA 2026-03-10
ER

PT J
AU YONISHROUACH, E
   RESNITZKY, D
   LOTEM, J
   SACHS, L
   KIMCHI, A
   OREN, M
AF YONISHROUACH, E
   RESNITZKY, D
   LOTEM, J
   SACHS, L
   KIMCHI, A
   OREN, M
TI WILD-TYPE P53 INDUCES APOPTOSIS OF MYELOID LEUKEMIC-CELLS THAT IS INHIBITED BY INTERLEUKIN-6
SO NATURE
LA English
DT Article
ID tumor suppression; c-myc; growth; differentiation; expression; gene; protein; oncogene; survival; bcl-2
AB WILD-TYPE p53 protein has many properties consistent with its being the product of a tumour suppressor gene 1-3. Although the normal roles of tumour suppressor genes are still largely unknown, it seems that they could be involved in promoting cell differentiation 4-6 as well as in mediating growth arrest by growth-inhibitory cytokines 7-9. Hence, the abrogation of wild-type p53 expression, which is a common feature of many tumours, could eliminate these activities. We have now tested this notion by restoring the expression of p53 in a murine myeloid leukaemic cell line that normally lacks p53. The use of a temperature-sensitive p53 mutant 10 allowed us to analyse cells in which the introduced p53 had either wild-type or mutant properties. Although there seemed to be no effect on differentiation, the introduction of wild-type p53 resulted in rapid loss of cell viability in a way characteristic of apoptosis (programmed cell death). The effect of wild-type p53 was counteracted by interleukin-6. Thus products of tumour suppressor genes could be involved in restricting precursor cell populations by mediating apoptosis.
C1 WEIZMANN INST SCI, DEPT CHEM IMMUNOL, IL-76100 REHOVOT, ISRAEL.
   WEIZMANN INST SCI, DEPT MOLEC GENET & VIROL, IL-76100 REHOVOT, ISRAEL.
C3 Weizmann Institute of Science; Weizmann Institute of Science
NR 41
TC 2178
Z9 2346
U1 0
U2 47
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD JUL 25
PY 1991
VL 352
IS 6333
BP 345
EP 347
DI 10.1038/352345a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FY289
UT WOS:A1991FY28900074
PM 1852210
DA 2026-03-10
ER

PT J
AU FAN, CM
   MANIATIS, T
AF FAN, CM
   MANIATIS, T
TI GENERATION OF P50 SUBUNIT OF NF-KAPPA-B BY PROCESSING OF P105 THROUGH AN ATP-DEPENDENT PATHWAY
SO NATURE
LA English
DT Article
ID interferon gene-regulation; enhancer-binding-protein; rel; purification; mediator
AB THE transcription factor NF-kappa-B is a heterodimer consisting of two proteins encoded by different members of the rel gene family (p50 and p65) 1-7. The p50 subunit is unusual among DNA-binding proteins in that its functional form is encoded in an open reading frame of relative molecular mass 105,000 (p105; ref. 4). The N-terminal region of this open reading frame encodes p50, whereas the remaining C terminus contains ankyrin repeats. Although p50 binds to DNA, full-length p105 translated in vitro does not 4,5. The mechanism by which p50 is generated in vivo, and the fate of the C-terminal region of p105 have not been established. Here we show that functional p50 is produced by ATP-dependent proteolysis of p105. Moreover, we find that the C-terminal half of p 105 is not required for processing in vivo, and is rapidly degraded on processing. We propose that the C-terminal region of p105 is involved in the cytoplasmic assembly of the complex between the p50/p65 heterodimer and the inhibitor I-kappa-B.
RP FAN, CM (corresponding author), HARVARD UNIV,DEPT BIOCHEM & MOLEC BIOL,7 DIVIN AVE,CAMBRIDGE,MA 02138, USA.
NR 19
TC 286
Z9 337
U1 0
U2 13
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 5
PY 1991
VL 354
IS 6352
BP 395
EP 398
DI 10.1038/354395a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT761
UT WOS:A1991GT76100052
PM 1956402
DA 2026-03-10
ER

PT J
AU DOUGLAS, SE
   MURPHY, CA
   SPENCER, DF
   GRAY, MW
AF DOUGLAS, SE
   MURPHY, CA
   SPENCER, DF
   GRAY, MW
TI CRYPTOMONAD ALGAE ARE EVOLUTIONARY CHIMERAS OF 2 PHYLOGENETICALLY DISTINCT UNICELLULAR EUKARYOTES
SO NATURE
LA English
DT Article
ID subunit ribosomal-rna; c-containing alga; organelles; origins; dna
AB ALTHOUGH it is widely accepted that the plastids of plants and algae originated as endosymbionts 1, the details of this evolutionary process are unclear 2,3.  It has been proposed that in organisms whose plastids are surrounded by more than two membranes, the endosymbiont was a eukaryotic alga rather than a photosynthetic prokaryote 4.  The DNA-containing 5 nucleomorph 6 of cryptomonad algae appears to be the vestigial nucleus of such an algal endosymbiont 7.  Eukaryotic-type ribosomal RNA sequences have been localized to a nucleolus-like structure in the nucleomorph 8.  In support of the hypothesis that cryptomonads are evolutionary chimaeras of two distinct eukaryotic cells, we show here that Cryptomonas PHI contains two phylogenetically separate, nuclear-type small-subunit rRNA genes, both of which are transcriptionally active.  We incorporate our rRNA sequence data into phylogenetic trees, from which we infer the evolutionary ancestry of the host and symbiont components of Cryptomonas PHI.  Such trees do not support the thesis 3 that chromophyte algae evolved directly from a cryptomonad-like ancestor.
C1 DALHOUSIE UNIV,DEPT BIOCHEM,HALIFAX B3H 4H7,NS,CANADA.
C3 Dalhousie University
RP DOUGLAS, SE (corresponding author), NATL RES COUNCIL CANADA,ATLANTIC REG LAB,INST MARINE BIOSCI,1411 OXFORD ST,HALIFAX B3H 3Z1,NS,CANADA.
NR 27
TC 248
Z9 254
U1 0
U2 7
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 14
PY 1991
VL 350
IS 6314
BP 148
EP 151
DI 10.1038/350148a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FB645
UT WOS:A1991FB64500056
PM 2005963
DA 2026-03-10
ER

PT J
AU JOOS, F
   SARMIENTO, JL
   SIEGENTHALER, U
AF JOOS, F
   SARMIENTO, JL
   SIEGENTHALER, U
TI ESTIMATES OF THE EFFECT OF SOUTHERN-OCEAN IRON FERTILIZATION ON ATMOSPHERIC CO2 CONCENTRATIONS
SO NATURE
LA English
DT Article
ID pco2
AB IT has been suggested 1-3 that fertilizing the ocean with iron might offset the continuing increase in atmospheric CO2 by enhancing the biological uptake of carbon, thereby decreasing the surface-ocean partial pressure of CO2 and drawing down CO2 from the atmosphere.  Using a box model, we present estimates of the maximum possible effect of iron fertilization, assuming that iron is continuously added to the phosphate-rich waters of the Southern Ocean, which corresponds to 16% of the world ocean surface.  We find that after 100 years of fertilization, the atmospheric CO2 concentration would be 59 p.p.m. below what it would have been with no fertilization, assuming no anthropogenic CO2 emissions, and 90-107 p.p.m. less when anthropogenic emissions are included in the calculation.  Such a large uptake of CO2 is unlikely to be achieved in practice, owing to a variety of constraints that require further study; the effect of iron fertilization on the ecology of the Southern Ocean also remains to be evaluated.  Thus, the most effective and reliable strategy for reducing future increases in atmospheric CO2 continues to be control of anthropogenic emissions.
C1 PRINCETON UNIV,ATMOSPHER & OCEAN SCI PROGRAM,PRINCETON,NJ 08544.
C3 National Oceanic Atmospheric Admin (NOAA) - USA; Princeton University
RP JOOS, F (corresponding author), UNIV BERN,INST PHYS,CH-3012 BERN,SWITZERLAND.
NR 24
TC 99
Z9 107
U1 5
U2 40
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD FEB 28
PY 1991
VL 349
IS 6312
BP 772
EP 775
DI 10.1038/349772a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EZ666
UT WOS:A1991EZ66600049
DA 2026-03-10
ER

PT J
AU PARDO, JV
   FOX, PT
   RAICHLE, ME
AF PARDO, JV
   FOX, PT
   RAICHLE, ME
TI LOCALIZATION OF A HUMAN SYSTEM FOR SUSTAINED ATTENTION BY POSITRON EMISSION TOMOGRAPHY
SO NATURE
LA English
DT Article
ID intravenous (h2o)-o-15; human-brain; pet images; cortex
AB POSITRON emission tomographic (PET) studies of human attention have begun to dissect isolable components of this complex higher brain function, including a midline attentional system in a region of the anterior cingulate cortex1-3.  The right hemisphere may play a special part in human attention4; neglect, an important phenomenon associated with damage to attentional systems, is more severe, extensive and long-lasting after lesions to the right hemisphere.  Here we use PET measurements of brain flood flow in healthy subjects to identify changes in regional brain activity during simple visual and somatosensory tasks of sustained attention or vigilance.  We find localized increases in blood flow in the prefrontal and superior parietal cortex primarily in the right hemisphere, regardless of the modality or laterality of sensory input.  The anterior cingulate was not activated during either task.  These data localize the vigilance aspects of normal human attention to sensory stimuli, thereby clarifying the biology underlying asymmetries of attention to such stimuli that have been reported in clinical lesions.
C1 WASHINGTON UNIV,MED CTR,DEPT NEUROL & NEUROL SURG,ST LOUIS,MO 63110.
   WASHINGTON UNIV,MED CTR,DEPT PSYCHIAT,ST LOUIS,MO 63110.
   WASHINGTON UNIV,MED CTR,MALLINCKRODT INST RADIOL,ST LOUIS,MO 63110.
   WASHINGTON UNIV,MED CTR,MCDONNELL CTR STUDIES HIGHER BRAIN FUNCT,ST LOUIS,MO 63110.
C3 Washington University (WUSTL); Washington University (WUSTL); Washington University (WUSTL); Washington University (WUSTL)
NR 16
TC 1083
Z9 1170
U1 0
U2 51
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JAN 3
PY 1991
VL 349
IS 6304
BP 61
EP 64
DI 10.1038/349061a0
PG 4
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA EQ601
UT WOS:A1991EQ60100050
PM 1985266
DA 2026-03-10
ER

PT J
AU BARRETT, SCH
   CHARLESWORTH, D
AF BARRETT, SCH
   CHARLESWORTH, D
TI EFFECTS OF A CHANGE IN THE LEVEL OF INBREEDING ON THE GENETIC LOAD
SO NATURE
LA English
DT Article
ID plant-populations; deleterious mutations; depression; evolution; rates; locus
AB "THE effects of inbreeding may not be as noticeable in the first generation as the invigoration immediately apparent after crossing" 1. This statement, published in 1919, has received little attention, and has apparently never been tested empirically, although the reduction of the genetic load of populations by inbreeding is well known in theoretical terms 2-5.  Because inbreeding increases homozygosity, and hence the effectiveness of selection against recessive or partially recessive detrimental alleles, changes in levels of inbreeding can lead to a reduction in the frequencies of such mutant alleles. This results in equilibration at higher population mean fitness 6 and is referred to as 'purging' populations of their genetic load. Severe inbreeding can also reduce genetic load due to overdominant alleles, provided selection coefficients are not symmetrical at all loci, because alleles giving lower fitness will be reduced in frequency at equilibrium 7-8.  With either fitness model, however, reduction in genetic load takes time, and the initial effect of an increase in inbreeding is reduced fitness due to homozygosity. There are few data relating to the extent to which fitness is reduced during inbreeding in a set of lines and to how long the reduction lasts before increasing again to the initial level, or higher. Inbreeding experiments involving sib mating in mice and Drosophila subobscura 10, and successive bottlenecks in house flies 11 have yielded some evidence consistent with the purging hypothesis. Here, we report results of an experiment demonstrating a prolonged time-course of recovery of mean fitness under self-fertilization of a naturally outcrossing plant, and also compare our results with expectations derived by computer calculations. Our results show that the genetic load present in an outcrossing population can be explained only with a high mutation rate to partially recessive deleterious alleles, and that inbreeding purges the population of mutant alleles.
C1 UNIV CHICAGO,DEPT ECOL & EVOLUT,CHICAGO,IL 60637.
C3 University of Chicago
RP BARRETT, SCH (corresponding author), UNIV TORONTO,DEPT BOT,25 WILLCOCKS ST,TORONTO M5S 3B2,ONTARIO,CANADA.
NR 24
TC 370
Z9 402
U1 1
U2 90
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD AUG 8
PY 1991
VL 352
IS 6335
BP 522
EP 524
DI 10.1038/352522a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GA226
UT WOS:A1991GA22600060
PM 1865906
DA 2026-03-10
ER

PT J
AU BRUNK, BP
   MARTIN, EC
   ADLER, PN
AF BRUNK, BP
   MARTIN, EC
   ADLER, PN
TI DROSOPHILA GENES POSTERIOR SEX COMBS AND SUPPRESSOR 2 OF ZESTE ENCODE PROTEINS WITH HOMOLOGY TO THE MURINE BMI-1 ONCOGENE
SO NATURE
LA English
DT Article
ID virus type-1; expression; domains; sequence; binding; finger
AB THE Polycomb group (Pc-G) genes are needed to maintain expression patterns of the homeotic selector genes of the Antennapedia (Antp-C) and bithorax (bx-C) complexes, and hence for the maintenance of segmental determination 1-3. We report the predicted protein sequence of the Pc-G gene Posterior Sex Combs (Psc), and of the neighbouring and related gene Suppressor two of zeste (Su(z)2). Both genes encode large proteins that contain a 200 amino-acid domain identical over 37.4% that is also conserved in the murine oncogene bmi-1 (refs 4, 5). At the amino terminus of this domain is a cysteine-rich sequence that has been proposed as a novel type of zinc finger 6.
C1 UNIV VIRGINIA, INST MOLEC BIOL, DEPT BIOL, CHARLOTTESVILLE, VA 22901 USA.
   UNIV VIRGINIA, CTR CANC, CHARLOTTESVILLE, VA 22901 USA.
C3 University of Virginia; University of Virginia
NR 25
TC 191
Z9 210
U1 0
U2 7
PU NATURE PUBLISHING GROUP
PI LONDON
PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
SN 0028-0836
EI 1476-4687
J9 NATURE
JI Nature
PD SEP 26
PY 1991
VL 353
IS 6342
BP 351
EP 353
DI 10.1038/353351a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GG654
UT WOS:A1991GG65400060
PM 1833647
DA 2026-03-10
ER

PT J
AU MACEJAK, DG
   SARNOW, P
AF MACEJAK, DG
   SARNOW, P
TI INTERNAL INITIATION OF TRANSLATION MEDIATED BY THE 5' LEADER OF A CELLULAR MESSENGER-RNA
SO NATURE
LA English
DT Article
ID cap-binding-protein; secondary structure; noncoding region; poliovirus; virus; cells; gene; conservation; involvement; adenovirus
AB A RIBOSOME-SCANNING model has been proposed to explain the initiation of eukaryotic messenger RNAs 1 in which binding of the 43S ternary ribosomal subunit near or at the 5' end of the mRNA is facilitated by an interaction between the methylated cap-structure at the end of the mRNA and the cap-binding protein complex eIF-4F (refs 2, 3). But picornaviral mRNAs do not have a 5' terminal cap structure and are translated by internal ribosome binding 4-7.  A cellular mRNA, encoding the immunoglobulin heavy-chain binding protein, can be translated in poliovirus-infected cells at a time when cap-dependent translation of host cell mRNAs is inhibited 8.  We report here that the 5' leader of the binding protein mRNA can directly confer internal ribosome binding to an mRNA in mammalian cells, indicating that translation initiation by an internal ribosome-binding mechanism is used by eukaryotic mRNAs.
C1 UNIV COLORADO,HLTH SCI CTR,DEPT MICROBIOL & IMMUNOL,DENVER,CO 80262.
C3 University of Colorado System; University of Colorado Denver; University of Colorado Anschutz Medical Campus
RP MACEJAK, DG (corresponding author), UNIV COLORADO,HLTH SCI CTR,DEPT BIOCHEM BIOPHYS & GENET,MOLEC BIOL PROGRAM,DENVER,CO 80262, USA.
NR 24
TC 481
Z9 885
U1 0
U2 8
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD SEP 5
PY 1991
VL 353
IS 6339
BP 90
EP 94
DI 10.1038/353090a0
PG 5
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GD805
UT WOS:A1991GD80500067
PM 1652694
DA 2026-03-10
ER

PT J
AU ASHWORTH, A
   RASTAN, S
   LOVELLBADGE, R
   KAY, G
AF ASHWORTH, A
   RASTAN, S
   LOVELLBADGE, R
   KAY, G
TI X-CHROMOSOME INACTIVATION MAY EXPLAIN THE DIFFERENCE IN VIABILITY OF XO HUMANS AND MICE
SO NATURE
LA English
DT Article
ID sex-determining region; controlling elements; y-chromosome; mouse; gene; mutation; zfx; expression; protein; finger
AB ONLY about 1% of human XO conceptuses survive to birth and these usually have the characteristics of Turner's syndrome, with a complex and variable phenotype including short stature, gonadal dysgenesis and anatomical defects 1.  Both the embryonic lethality and Turner's syndrome are thought to be due to monosomy for a gene or genes common to the X and Y chromosomes 2.  These genes would be expected to be expressed in females from both active and inactive X chromosomes to ensure correct dosage of gene product.  Two genes with these properties are ZFX and RPS4X, both of which have been proposed to play a role in Turner's syndrome 3, 4.  In contrast to humans, mice that are XO are viable with no prenatal lethality (P. Burgoyne, personal communication) and are anatomically normal and fertile.  We have devised a system to analyse whether specific genes on the mouse X chromosome are inactivated, and demonstrate that both Zfx and Rps4X undergo normal X-inactivation in mice.  Thus the relative viability of XO mice compared to XO humans may be explained by differences between the two species in the way that dosage compensation of specific genes is achieved.
C1 MRC,CLIN RES CTR,COMPARAT BIOL SECT,HARROW HA1 3UJ,MIDDX,ENGLAND.
   NATL INST MED RES,EUKARYOT MOLEC GENET LAB,LONDON NW7 1AA,ENGLAND.
C3 Medical Research Council Clinical Trials Unit; MRC National Institute for Medical Research
RP ASHWORTH, A (corresponding author), INST CANC RES,CHESTER BEATTY LABS,FULHAM RD,LONDON SW3 6JB,ENGLAND.
FU Medical Research Council [MC_U117562207] Funding Source: Medline
NR 29
TC 120
Z9 123
U1 0
U2 5
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAY 30
PY 1991
VL 351
IS 6325
BP 406
EP 408
DI 10.1038/351406a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FN856
UT WOS:A1991FN85600058
PM 2034290
DA 2026-03-10
ER

PT J
AU DUPREE, AK
   WHITNEY, BA
AF DUPREE, AK
   WHITNEY, BA
TI CA-II EMISSION FROM OLD RED GIANTS IN THE GLOBULAR CLUSTER-M15
SO NATURE
LA English
DT Article
ID fk comae; stars
AB MURPHY et al. 1 recently observed characteristic emission of Ca II from the globular cluster M15, and argued that this emission came from a population of primordial binary stars. Their conclusion appears theoretically attractive in relation to the study of the dynamics and evolution of globular clusters 2,3. We argue here, however, that the Ca II K-line emission in various types of hard binary systems differs in strength and width from the M15 spectra, and we demonstrate that the M15 emission closely resembles that from metal-deficient red giants of the halo population in our Galaxy. Chromospheric activity, indicated by emission in Ca II, H-alpha and Mg II, occurs in red giants in both globular clusters and halo-population field giants 4-6. A simple detection of Ca II emission is thus not a unique signature of binaries, and in the case of M15 we argue that red giants are the more likely cause.
RP DUPREE, AK (corresponding author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA.
NR 17
TC 3
Z9 3
U1 0
U2 0
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD NOV 28
PY 1991
VL 354
IS 6351
BP 284
EP 286
DI 10.1038/354284a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GT204
UT WOS:A1991GT20400039
DA 2026-03-10
ER

PT J
AU MAYER, LA
AF MAYER, LA
TI EXTRACTION OF HIGH-RESOLUTION CARBONATE DATA FOR PALEOCLIMATE RECONSTRUCTION
SO NATURE
LA English
DT Article
ID eastern equatorial pacific; time-series; sediments; productivity; record; ocean
AB TEMPORAL variations in the calcium carbonate content of deep-sea sediments provide direct stratigraphic as well as important palaeoenvironmental information relating to the global carbon cycle.  Here I present an algorithm that allows carbonate content and porosity to be accurately predicted from saturated bulk density in equatorial pelagic carbonates.  Applying the algorithm to continuous laboratory measurements of density made on DSDP and ODP cores yields a nearly continuous carbonate record for the upper approximately 200 m of the sediment section.  Long, ultra-high-resolution carbonate curves of this type should yield new insight into the evolution of the carbon chemistry of the oceans, as well as the role of external (Milankovitch) forcing in the development of the carbonate system.  The algorithm can also be applied to quantitative, high-resolution seismic data, thereby enabling detailed carbonate records to be extracted from remotely derived geophysical data.
RP MAYER, LA (corresponding author), DALHOUSIE UNIV,DEPT OCEANOG,HALIFAX B3H 4J1,NS,CANADA.
NR 27
TC 41
Z9 43
U1 0
U2 6
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD JUL 11
PY 1991
VL 352
IS 6331
BP 148
EP 150
DI 10.1038/352148a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FW097
UT WOS:A1991FW09700053
DA 2026-03-10
ER

PT J
AU FARRAR, GJ
   KENNA, P
   JORDAN, SA
   KUMARSINGH, R
   HUMPHRIES, MM
   SHARP, EM
   SHEILS, DM
   HUMPHRIES, P
AF FARRAR, GJ
   KENNA, P
   JORDAN, SA
   KUMARSINGH, R
   HUMPHRIES, MM
   SHARP, EM
   SHEILS, DM
   HUMPHRIES, P
TI A 3-BASE-PAIR DELETION IN THE PERIPHERIN-RDS GENE IN ONE FORM OF RETINITIS-PIGMENTOSA
SO NATURE
LA English
DT Article
ID rhodopsin gene; prevalence; mutations
AB THE group of retinopathies termed retinitis pigmentosa (RP) greatly contribute to visual dysfunction in man with a frequency of roughly 1 in 4,000 (refs 1, 2). We mapped the first autosomal dominant RP (adRP) gene to chromosome 3q (refs 3, 4), close to the gene encoding rhodopsin, a rod photoreceptor pigment protein. Subsequently, mutations in this gene have been implicated as responsible for some forms of adRP 5-9. Another adRP gene has been mapped to chromosome 8p (ref. 10). A third adRP gene in a large Irish pedigree has been mapped to chromosome 6p (refs 11, 12), showing tight linkage with the gene for peripherin 13,14, a photoreceptor cell-specific glycoprotein, which is thus a strong candidate for the defective gene. We have now identified a three-base-pair deletion which results in the loss of one of a pair of highly conserved cysteine residues in the predicted third transmembrane domain of peripherin. This deletion segregates with the disease phenotype but is not present in unaffected controls, and suggests that mutant peripherin gives rise to retinitis pigmentosa.
RP FARRAR, GJ (corresponding author), UNIV DUBLIN TRINITY COLL,DEPT GENET,LINCOLN PL GATE,DUBLIN 2,IRELAND.
FU Wellcome Trust Funding Source: Medline
NR 17
TC 358
Z9 391
U1 0
U2 3
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD DEC 12
PY 1991
VL 354
IS 6353
BP 478
EP 480
DI 10.1038/354478a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA GV078
UT WOS:A1991GV07800060
PM 1749427
DA 2026-03-10
ER

PT J
AU FOX, K
   DAW, N
   SATO, H
   CZEPITA, D
AF FOX, K
   DAW, N
   SATO, H
   CZEPITA, D
TI DARK-REARING DELAYS THE LOSS OF NMDA-RECEPTOR FUNCTION IN KITTEN VISUAL-CORTEX
SO NATURE
LA English
DT Article
ID methyl-d-aspartate; ocular dominance columns; cat; plasticity; neurons
AB SOME features of the visual cortex develop postnatally in mammals 1,2. For example, geniculocortical axons that initially overlap throughout cortical layer IV segregate postnatally into two sets of interleaved eye-specific bands 3,4.  NMDA (N-methyl-D-aspartate) receptors are necessary for eye-specific axon-segregation in the frog tectum 5, and as NMDA receptors play a greater part in synaptic transmission in early life 6,7 and decrease in function during the period of axon segregation, they may be involved in the segregation of geniculocortical axons:  they are well placed to do so as they transduce 8 retinally derived signals essential for segregation 9.  Rearing animals in the dark in early life delays segregation 10,11 and prolongs the critical period for plasticity 12.  We now report that dark-rearing of kittens also delays the loss of NMDA receptor function in the visual cortex, supporting the view that they play an important part in neuronal development and plasticity.
C1 WASHINGTON UNIV,SCH MED,DEPT CELL BIOL & PHYSIOL,ST LOUIS,MO 63110.
   WASHINGTON UNIV,SCH MED,MCDONNELL CTR STUDIES HIGHER BRAIN FUNCT,ST LOUIS,MO 63110.
C3 Washington University (WUSTL); Washington University (WUSTL)
NR 22
TC 105
Z9 110
U1 0
U2 1
PU MACMILLAN MAGAZINES LTD
PI LONDON
PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF
SN 0028-0836
EI 
J9 NATURE
JI Nature
PD MAR 28
PY 1991
VL 350
IS 6316
BP 342
EP 344
DI 10.1038/350342a0
PG 3
WC Multidisciplinary Sciences
SC Science & Technology - Other Topics
GA FD838
UT WOS:A1991FD83800093
PM 1672557
DA 2026-03-10
ER

