Abstract:
:Ice-core records show that climate changes in the past have been large, rapid, and synchronous over broad areas extending into low latitudes, with less variability over historical times. These ice-core records come from high mountain glaciers and the polar regions, including small ice caps and the large ice sheets of Greenland and Antarctica.
journal_name
Proc Natl Acad Sci U S Aauthors
Alley RBdoi
10.1073/pnas.97.4.1331keywords:
subject
Has Abstractpub_date
2000-02-15 00:00:00pages
1331-4issue
4eissn
0027-8424issn
1091-6490pii
97/4/1331journal_volume
97pub_type
杂志文章abstract::The mechanistic target of rapamycin complex 1 (mTORC1) growth pathway detects nutrients through a variety of sensors and regulators that converge on the Rag GTPases, which form heterodimers consisting of RagA or RagB tightly bound to RagC or RagD and control the subcellular localization of mTORC1. The Rag heterodimer ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1811727115
更新日期:2018-09-18 00:00:00
abstract::Spatial organization of the binding sites for the priming substrate, the template DNA, and the transcription inhibitor rifampicin (Rif) in Escherichia coli RNA polymerase (EC 2.7.7.6) was probed with chimeric compounds in which Rif is covalently attached to a ribonucleotide. The compounds bind to RNA polymerase in bif...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.25.12036
更新日期:1994-12-06 00:00:00
abstract::Analysis, by the recovery of specific genetic "markers," of the effects of DNase I, physical shear, and temperature shock on DNA-cell complexes demonstrates that sequential attachment of both ends of bacteriophage SP82G DNA to Bacillus subtilis precedes entry of the DNA molecule into the cell, and that each attachment...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.69.6.1545
更新日期:1972-06-01 00:00:00
abstract::Metal-catalyzed oxidation results in loss of function and structural alteration of proteins. The oxidative process affects a variety of side amino acid groups, some of which are converted to carbonyl compounds. Spectrophotometric measurement of these moieties, after their reaction with 2,4-dinitrophenylhydrazine, is a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.011526698
更新日期:2001-01-02 00:00:00
abstract::In a microarray-based gene profiling analysis of Müller glia-derived retinal stem cells in light-damaged retinas from adult zebrafish, we found that 2 genes required for regeneration of fin and heart tissues in zebrafish, hspd1 (heat shock 60-kDa protein 1) and mps1 (monopolar spindle 1), were up-regulated. Expression...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0811186106
更新日期:2009-06-09 00:00:00
abstract::The prefrontal cortex plays a fundamental role in the working memory functions of the cerebral cortex and is also the site of dysfunction in several neurological and psychiatric disorders, including schizophrenia. Prefrontal neurons are distinguished by their capacity for sustained activity during the time a stimulus ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.011524298
更新日期:2001-01-02 00:00:00
abstract::Cryptococcus neoformans (CN), an encapsulated, ubiquitous environmental yeast, is pathogenic for humans, primarily those with compromised immune function. CN is believed to be a facultative intracellular pathogen. Time-lapsed video microscopy revealed that yeast began to replicate and divide 2 hours after ingestion by...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.052702799
更新日期:2002-03-05 00:00:00
abstract::We have examined whether dissociation of the histone octamer is required for elongation of RNA transcripts through arrays of nucleosome cores in vitro. Control or dimethyl suberimidate-crosslinked histone octamers were reconstituted onto supercoiled, closed circular pT207-18 DNA, which contains tandemly repeated 207-b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.13.6203
更新日期:1993-07-01 00:00:00
abstract::The controversy over the interpretation of DNA profile evidence in forensic identification can be attributed in part to confusion over the mode(s) of statistical inference appropriate to this setting. Although there has been substantial discussion in the literature of, for example, the role of population genetics issu...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.25.11741
更新日期:1995-12-05 00:00:00
abstract::A surprising example of interspecies competition is the production by certain bacteria of hydrogen peroxide at concentrations that are lethal for others. A case in point is the displacement of Staphylococcus aureus by Streptococcus pneumoniae in the nasopharynx, which is of considerable clinical significance. How it i...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0809600106
更新日期:2009-01-27 00:00:00
abstract::To elucidate the roles of IgE antibody in host responses to helminth infection, selective IgE-deficient SJA/9 mice were infected with the nematode parasites Nippostrongylus brasiliensis, which elicits remarkable potentiated IgE production, and Trichinella spiralis, which induces strong anti-Trichinella IgE antibody pr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.12.4460
更新日期:1988-06-01 00:00:00
abstract::Neurogenesis has recently been observed in the adult human brain, suggesting the possibility of endogenous neural repair. However, the augmentation of neurogenesis in the adult human brain in response to neuronal cell loss has not been demonstrated. This study was undertaken to investigate whether neurogenesis occurs ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1532244100
更新日期:2003-07-22 00:00:00
abstract::A computational model is presented that can be used as a tool in the design of safer chemicals. This model predicts the rate of hydrogen-atom abstraction by cytochrome P450 enzymes. Excellent correlations between biotransformation rates and the calculated activation energies (delta Hact) of the cytochrome P450-mediate...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.24.11076
更新日期:1995-11-21 00:00:00
abstract::When T cells become infected by the parasite Theileria parva, they acquire a transformed phenotype and no longer require antigen-specific stimulation or exogenous growth factors. This is accompanied by constitutive interleukin 2 (IL-2) and IL-2 receptor expression. Transformation can be reversed entirely by eliminatio...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.10.5119
更新日期:1997-05-13 00:00:00
abstract::Environmental cues are transmitted to the interior of the cell via a complex network of signaling hubs. Receptor tyrosine kinases (RTKs) and trimeric G proteins are two such major signaling hubs in eukaryotes. Conventionally, canonical signal transduction via trimeric G proteins is thought to be triggered exclusively ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1420140112
更新日期:2015-03-03 00:00:00
abstract::Establishing a timeline for the evolution of novelties is a common, unifying goal at the intersection of evolutionary and developmental biology. Analyses of gene regulatory networks (GRNs) provide the ability to understand the underlying genetic and developmental mechanisms responsible for the origin of morphological ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1610603114
更新日期:2017-06-06 00:00:00
abstract::Real-world studies show that the facial expressions produced during pain and orgasm-two different and intense affective experiences-are virtually indistinguishable. However, this finding is counterintuitive, because facial expressions are widely considered to be a powerful tool for social interaction. Consequently, de...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1807862115
更新日期:2018-10-23 00:00:00
abstract::We have cloned a murine cDNA encoding a tyrosine kinase receptor with about 90% similarity to the chicken fibroblast growth factor (FGF) receptor and the human fms-like gene (FLG) tyrosine kinase. This mouse receptor lacks 88 amino acids in the extracellular portion, leaving only two immunoglobulin-like domains compar...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.11.4378
更新日期:1990-06-01 00:00:00
abstract::Class I gene products D, L, and R encoded by the D region of the H-2q haplotype were isolated by sequential immunoprecipitation from Nonidet P-40 extracts of B10.AKM murine spleen cells. Primary structural comparisons of these molecules were made by tryptic peptide map analyses and radiochemical amino acid sequence de...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.8.2499
更新日期:1984-04-01 00:00:00
abstract::Silicate melts at the top of the transition zone and the core-mantle boundary have significant influences on the dynamics and properties of Earth's interior. MgSiO3-rich silicate melts were among the primary components of the magma ocean and thus played essential roles in the chemical differentiation of the early Eart...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0802667105
更新日期:2008-06-10 00:00:00
abstract::Adoptive cellular immunotherapy, infusions of interleukin 2 (IL-2) in conjunction with in vitro-activated killer cells, has brought new hope to patients with cancer. The broad application of this strategy, however, is constrained by the need for repeated leukapheresis and by the labor-intensive process of in vitro act...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.17.7889
更新日期:1994-08-16 00:00:00
abstract::To study the role of low-abundance, embryonic muscle-specific gene transcripts, we have developed a method to screen cDNA clones from embryonic muscle for such sequences. The protocol involves two stages: first, partial enrichment for cDNA clones carrying possible embryo-specific sequences by selecting clones of low-a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.77.8.4519
更新日期:1980-08-01 00:00:00
abstract::Sonicated rabbit-liver chromatin is fractionated by ion-exchange chromatography on ECTHAM-cellulose, a weakly cationic adsorbent. The chromatographic procedure provides a series of fractions having a spectrum of thermal denaturation profiles. The earliest-eluting fractions melt cooperatively at a significantly higher ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.69.8.2317
更新日期:1972-08-01 00:00:00
abstract::Temperate-zone species have responded to warming temperatures by shifting their distributions poleward and upslope. Thermal tolerance data suggests that tropical species may respond to warming temperatures even more strongly than temperate-zone species, but this prediction has yet to be tested. We addressed this data ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1318190111
更新日期:2014-03-25 00:00:00
abstract::Antibiotic resistance in bacteria has emerged as a global challenge over the past 90 years, compromising our ability to effectively treat infections. There has been a dramatic increase in antibiotic resistance-associated determinants in bacterial populations, driven by the mobility and infectious nature of such determ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1717162115
更新日期:2018-12-18 00:00:00
abstract::An evolutionarily ancient plant hormone receptor complex comprising the α/β-fold hydrolase receptor KARRIKIN INSENSITIVE 2 (KAI2) and the F-box protein MORE AXILLARY GROWTH 2 (MAX2) mediates a range of developmental responses to smoke-derived butenolides called karrikins (KARs) and to yet elusive endogenous KAI2 ligan...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2006111117
更新日期:2020-09-01 00:00:00
abstract::The structure of the non-self-complementary DNA heptamer d(CGACGAC) at low pH has been determined by the quantitative NMR refinement procedure designated SPEDREF (SPEctral-Driven REFinement). Acid-base titration of the molecule indicated a prominent n = 2 pKa near 6.8. In the pH range up to 6.0, the heptamer forms a r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.11.5224
更新日期:1993-06-01 00:00:00
abstract::Neurotrophins (NTs) have recently been found to regulate synaptic transmission in the hippocampus. Whole-cell and single-channel recordings from cultured hippocampal neurons revealed a mechanism responsible for enhanced synaptic strength. Specifically, brain-derived neurotrophic factor augmented glutamate-evoked, but ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.17.10235
更新日期:1998-08-18 00:00:00
abstract::I have determined the nucleotide sequence of the ampicillin resistance gene of pBR322, an Escherichia coli plasmid that encodes a penicillin beta-lactamase. This gene codes for a protein of 286 amino acid residues. The first 23 amino acids presumably form a signal for secretion, because they do not appear in the matur...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.75.8.3737
更新日期:1978-08-01 00:00:00
abstract::In 1944, Freeman Dyson conjectured the existence of a "crank" function for partitions that would provide a combinatorial proof of Ramanujan's congruence modulo 11. Forty years later, Andrews and Garvan successfully found such a function and proved the celebrated result that the crank simultaneously "explains" the thre...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0506702102
更新日期:2005-10-25 00:00:00