Stimulation of T cells by antigenic peptide complexed with isolated chains of major histocompatibility complex class II molecules.

abstract：:This study quantifies sex differences in the diurnal and circadian variation of sleep and waking while controlling for menstrual cycle phase and hormonal contraceptive use. We compared the diurnal and circadian variation of sleep and alertness of 8 women studied during two phases of the menstrual cycle and 3 women stu...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Boivin DB,Shechter A,Boudreau P,Begum EA,Ng Ying-Kin NM

更新日期：2016-09-27 00:00:00

abstract：:A "supercooled" liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific id...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Kassner ER,Eyvazov AB,Pichler B,Munsie TJ,Dabkowska HA,Luke GM,Davis JC

更新日期：2015-07-14 00:00:00

abstract：:The trace fossil record is important in determining the timing of the appearance of bilaterian animals. A conservative estimate puts this time at approximately equal 555 million years ago. The preservational potential of traces made close to the sediment-water interface is crucial to detecting early benthic activity. ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Droser ML,Jensen S,Gehling JG

更新日期：2002-10-01 00:00:00

abstract：:A patient with type II diabetes associated with hyperproinsulinemia has been shown to have a point mutation in one insulin gene allele, resulting in replacement of histidine with aspartic acid at position 10 of the B-chain. To investigate the basis of the proinsulin processing defect, we introduced an identical mutati...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Gross DJ,Halban PA,Kahn CR,Weir GC,Villa-Komaroff L

更新日期：1989-06-01 00:00:00

abstract：:We have recently established that several mRNAs encode the PR264/SC35 splicing factor and that their expression is related to that of c-Myb in human hematopoietic cells. We now report that the various PR264 mRNAs whose expression is transactivated by c-Myb proteins encode an identical PR264/SC35 polypeptide. These mRN...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Sureau A,Perbal B

更新日期：1994-02-01 00:00:00

abstract：:A central question in protein-DNA recognition is the origin of the specificity that permits binding to the correct site in the presence of excess, nonspecific DNA. In the P22 Arc repressor, the Phe-10 side chain is part of the hydrophobic core of the free protein but rotates out to pack against the sugar-phosphate bac...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Schildbach JF,Karzai AW,Raumann BE,Sauer RT

更新日期：1999-02-02 00:00:00

abstract：:Translation elongation factor P (EF-P) stimulates ribosomal peptidyltransferase activity. EF-P is conserved in bacteria and is essential for cell viability. Eukarya and Archaea have an EF-P homologue, eukaryotic initiation factor 5A (eIF-5A). In the present study, we determined the crystal structure of EF-P from Therm...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hanawa-Suetsugu K,Sekine S,Sakai H,Hori-Takemoto C,Terada T,Unzai S,Tame JR,Kuramitsu S,Shirouzu M,Yokoyama S

更新日期：2004-06-29 00:00:00

abstract：:The chloroplast stromal proteins from spinach condense the two heterocyclic moieties of vitamin B1--4-methyl-5-(beta-hydroxyethyl)thiazole and 2-methyl-4-amino-5-hydroxymethylpyrimidine--in the presence of MgATP. We have taken advantage of this observation to study thiazole synthesis. We present data indicating that p...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Julliard JH,Douce R

更新日期：1991-03-15 00:00:00

abstract：:The preliminary structural characterization of a reversible ferrous dioxygen complex is reported. Mono(N-methyl imidazole) (dioxygen) meso-tetra (alpha,alpha,alpha,alpha-o-pivalamidephenyl) porphinatorino(II), [Fe(O(2))-(N-Me imid) (alpha,alpha,alpha,alpha-TpivPP)], 1, isolated from toluene solution, crystallizes in t...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Collman JP,Gagne RR,Reed CA,Robinson WT,Rodley GA

更新日期：1974-04-01 00:00:00

abstract：:A protein of 87 kilodaltons (87 kDa) was previously identified as a major specific substrate for protein kinase C in neuronal and other tissues. We have now studied the effect of protein kinase C-catalyzed phosphorylation of this protein on its association with membranes in isolated nerve terminals (synaptosomes) from...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wang JK,Walaas SI,Sihra TS,Aderem A,Greengard P

更新日期：1989-04-01 00:00:00

abstract：:The marine nitrogen fixing microorganisms (diazotrophs) are a major source of nitrogen to open ocean ecosystems and are predicted to be limited by iron in most marine environments. Here we use global and targeted proteomic analyses on a key unicellular marine diazotroph Crocosphaera watsonii to reveal large scale diel...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Saito MA,Bertrand EM,Dutkiewicz S,Bulygin VV,Moran DM,Monteiro FM,Follows MJ,Valois FW,Waterbury JB

更新日期：2011-02-08 00:00:00

abstract：:Integrable models form pillars of theoretical physics because they allow for full analytical understanding. Despite being rare, many realistic systems can be described by models that are close to integrable. Therefore, an important question is how small perturbations influence the behavior of solvable models. This is ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Žnidarič M,Ljubotina M

更新日期：2018-05-01 00:00:00

abstract：:Strategies to elicit Abs that can neutralize diverse strains of a highly mutable pathogen are likely to result in a potent vaccine. Broadly neutralizing Abs (bnAbs) against HIV have been isolated from patients, proving that the human immune system can evolve them. Using computer simulations and theory, we study immuni...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Shaffer JS,Moore PL,Kardar M,Chakraborty AK

更新日期：2016-11-08 00:00:00

abstract：:Bacterial conjugation systems are members of the large type IV secretion system (T4SS) superfamily. Conjugative transfer of F plasmids residing in the Enterobacteriaceae was first reported in the 1940s, yet the architecture of F plasmid-encoded transfer channel and its physical relationship with the F pilus remain unk...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hu B,Khara P,Christie PJ

更新日期：2019-07-09 00:00:00

abstract：:Traits that enable species to persist in ecological environments are often maintained over time, a phenomenon known as niche conservatism. Here we argue that ecological niches function at levels above species, notably at the level of genus for mammals, and that niche conservatism is also evident above the species leve...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hadly EA,Spaeth PA,Li C

更新日期：2009-11-17 00:00:00

abstract：:Saccharopolyspora erythraea makes erythromycin, an antibiotic commonly used in human medicine. Unusually, the erythromycin biosynthetic (ery) cluster lacks a pathway-specific regulatory gene. We isolated a transcriptional regulator of the ery biosynthetic genes from S. erythraea and found that this protein appears to ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Chng C,Lum AM,Vroom JA,Kao CM

更新日期：2008-08-12 00:00:00

abstract：:We have examined the process by which small groups of pigmented germinal cells transplanted orthotopically from stage 30-38 donor embryos into stage 28-38 albino hosts contribute new postmitotic cells to the pigmented retinal epithelium of the growing larval eye in Xenopus. In the great majority of chimeric eyes, the ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hunt RK,Cohen JS,Mason BJ

更新日期：1987-05-01 00:00:00

abstract：:To determine possible differences in the cyclic AMP-dependent protein kinases of normal and psoriatic human fibroblasts, the levels of the regulatory subunits (RI and RII, respectively) of protein kinase I and protein kinase II were quantitated by photoaffinity labeling with 8-azido[32P]cAMP. The level of RII was sign...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Brion DE,Raynaud F,Plet A,Laurent P,Leduc B,Anderson W

更新日期：1986-07-01 00:00:00

abstract：:The human gamma herpesviruses, Kaposi sarcoma-associated virus (KSHV) and EBV, are associated with multiple cancers. Recent evidence suggests that EBV and possibly other viruses can manipulate the tumor microenvironment through the secretion of specific viral and cellular components into exosomes, small endocytically ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Meckes DG Jr,Gunawardena HP,Dekroon RM,Heaton PR,Edwards RH,Ozgur S,Griffith JD,Damania B,Raab-Traub N

更新日期：2013-07-30 00:00:00

abstract：:Males of the androdioecious species Caenorhabditis elegans are more likely to attempt to mate with and successfully inseminate C. elegans hermaphrodites that do not concurrently harbor sperm. Although a small number of genes have been implicated in this effect, the mechanism by which it arises remains unknown. In the ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Leighton DH,Choe A,Wu SY,Sternberg PW

更新日期：2014-12-16 00:00:00

abstract：:Specific viral transformation rather than cell selection can explain the previously observed increase in the proportion of type III procollagen compared to type I procollagen in BALB 3T3 cells transformed by Kirsten murine sarcoma virus (Ki-MSV). Two subclones of BALB 3T3 A31 were productively infected with with a tem...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Bateman JF,Peterkofsky B

更新日期：1981-10-01 00:00:00

abstract：:High molecular weight RNA (35S) isolated from avian myeloblastosis virus directs the cell-free synthesis of two prominent polypeptides of 180,000 and 76,000 molecular weight. The latter polypeptide has previously been identified as the precursor to the group-specific antigens of the virus ("gag" proteins) [Vogt, V. M....

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Paterson BM,Marciani DJ,Papas TS

更新日期：1977-11-01 00:00:00

abstract：:The environmental backdrop to the evolution and spread of early Homo sapiens in East Africa is known mainly from isolated outcrops and distant marine sediment cores. Here we present results from new scientific drill cores from Lake Malawi, the first long and continuous, high-fidelity records of tropical climate change...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Scholz CA,Johnson TC,Cohen AS,King JW,Peck JA,Overpeck JT,Talbot MR,Brown ET,Kalindekafe L,Amoako PY,Lyons RP,Shanahan TM,Castañeda IS,Heil CW,Forman SL,McHargue LR,Beuning KR,Gomez J,Pierson J

更新日期：2007-10-16 00:00:00

abstract：:When propagated on arl strains (a subclass of Escherichia coli hyper-rec mutants), lambda "Red-" duplication phages accumulated an enhanced potential for recombination. The physical properties of the recombinogenic phages thus obtained ("Arl-" phages) were similar to those of phages grown on arl+ bacteria. However, Ar...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hays JB,Korba BE

更新日期：1979-12-01 00:00:00

abstract：:The boreal forests, identified as a critical "tipping element" of the Earth's climate system, play a critical role in the global carbon budget. Recent findings have suggested that terrestrial carbon sinks in northern high-latitude regions are weakening, but there has been little observational evidence to support the i...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Ma Z,Peng C,Zhu Q,Chen H,Yu G,Li W,Zhou X,Wang W,Zhang W

更新日期：2012-02-14 00:00:00

abstract：:Combinatorial antibody libraries have the potential to display the entire immunological record of an individual, allowing one to detect and recover any antibody ever made, irrespective of whether it is currently being produced. We have termed this the "fossil record" of an individual's antibody response. To determine ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Felding-Habermann B,Lerner RA,Lillo A,Zhuang S,Weber MR,Arrues S,Gao C,Mao S,Saven A,Janda KD

更新日期：2004-12-07 00:00:00

abstract：:Higher acenes have drawn much attention as promising organic semiconductors with versatile electronic properties. However, the nature of their ground state and electronic excited states is still not fully clear. Their unusual chemical reactivity and instability are the main obstacles for experimental studies, and the ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Yang Y,Davidson ER,Yang W

更新日期：2016-08-30 00:00:00

abstract：:The lentiviruses are associated with a wide range of chronic diseases in mammals. These include immunodeficiencies (such as HIV/AIDS in humans), malignancies, and lymphatic and neurological disorders in primates, felids, and a variety of wild and domesticated ungulates. Evolutionary analyses of the genomic sequences o...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Katzourakis A,Tristem M,Pybus OG,Gifford RJ

更新日期：2007-04-10 00:00:00

abstract：:The complete amino acid and DNA sequences of the human 40-kDa keratin are reported. The DNA sequence encodes a protein of 44,098 Da, which is unique in that it lacks the terminal non-alpha-helical tail segment found in all other keratins. When the human 40-kDa keratin amino acid sequence is compared to the correspondi...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Eckert RL

更新日期：1988-02-01 00:00:00

abstract：:The default mode network (DMN) has been suggested to support a variety of self-referential functions in humans and has been fractionated into subsystems based on distinct responses to cognitive tasks and functional connectivity architecture. Such subsystems are thought to reflect functional hierarchy and segregation w...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hsu LM,Liang X,Gu H,Brynildsen JK,Stark JA,Ash JA,Lin CP,Lu H,Rapp PR,Stein EA,Yang Y

更新日期：2016-08-02 00:00:00