Trophic cascades in a complex terrestrial community.

abstract：:Gradients of extracellular signaling molecules and transcription factors are used in a variety of developmental processes, including the patterning of the Drosophila embryo, the establishment of diverse neuronal cell types in the vertebrate neural tube, and the anterior-posterior patterning of vertebrate limbs. Here, ...

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

authors： Hong JW,Hendrix DA,Papatsenko D,Levine MS

更新日期：2008-12-23 00:00:00

abstract：:Hydrogen bonds and their relative strengths in proteins are of importance for understanding protein structure and protein motions. The correct strength of such hydrogen bonds is experimentally known to vary greatly from approximately 5-6 kcal/mol for the isolated bond to approximately 0.5-1.5 kcal/mol for proteins in ...

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

authors： Sheu SY,Yang DY,Selzle HL,Schlag EW

更新日期：2003-10-28 00:00:00

abstract：:The reported isolation of nanobacteria from human kidney stones raises the intriguing possibility that these microorganisms are etiological agents of pathological extraskeletal calcification [Kajander, E. O. & Ciftçioglu, N. (1998) Proc. Natl. Acad. Sci. USA 95, 8274-8279]. Nanobacteria were previously isolated from F...

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

authors： Cisar JO,Xu DQ,Thompson J,Swaim W,Hu L,Kopecko DJ

更新日期：2000-10-10 00:00:00

abstract：:Progressive amyloid deposition in senile plaques and cortical blood vessels may play a central role in the pathogenesis of Alzheimer disease. We have used x-ray diffraction and electron microscopy to study the molecular organization and morphology of macromolecular assemblies formed by three synthetic peptides homolog...

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

authors： Kirschner DA,Inouye H,Duffy LK,Sinclair A,Lind M,Selkoe DJ

更新日期：1987-10-01 00:00:00

abstract：:Photosystem II (PSII), the light-driven water/plastoquinone photooxidoreductase, is of central importance in the planetary energy cycle. The product of the reaction, plastohydroquinone (PQH2), is released into the membrane from the QB site, where it is formed. A plastoquinone (PQ) from the membrane pool then binds int...

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

authors： De Causmaecker S,Douglass JS,Fantuzzi A,Nitschke W,Rutherford AW

更新日期：2019-09-24 00:00:00

abstract：:Speech recognition involves three processes: extraction of acoustic indices from the speech signal, estimation of the probability that the observed index string was caused by a hypothesized utterance segment, and determination of the recognized utterance via a search among hypothesized alternatives. This paper is not ...

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

authors： Jelinek F

更新日期：1995-10-24 00:00:00

abstract：:In many song birds, males develop their songs as adults by imitating the songs of one or more tutors, memorized previously during a sensitive phase early in life. Previous work using two assays, the production of imitations by adult males and playback-induced calling by young birds during the sensitive phase for memor...

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

authors： Nelson DA

更新日期：2000-11-21 00:00:00

abstract：:The hippocampus and cerebellum are critically involved in trace eyeblink classical conditioning (EBCC). The mechanisms underlying the hippocampal-cerebellar interaction during this task are not well-understood, although hippocampal theta (3-7 Hz) oscillations are known to reflect a favorable state for EBCC. Two groups...

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

authors： Hoffmann LC,Berry SD

更新日期：2009-12-15 00:00:00

abstract：:In addition to guiding proteins to defined genomic loci, DNA can act as an allosteric ligand that influences protein structure and activity. Here we compared genome-wide binding, transcriptional regulation, and, using NMR, the conformation of two glucocorticoid receptor (GR) isoforms that differ by a single amino acid...

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

authors： Thomas-Chollier M,Watson LC,Cooper SB,Pufall MA,Liu JS,Borzym K,Vingron M,Yamamoto KR,Meijsing SH

更新日期：2013-10-29 00:00:00

abstract：:The genome of the defective avian tumor virus MH2 was identified as a RNA of 5.7 kilobases by its presence in different MH2-helper virus complexes and its absence from pure helper virus, by its unique fingerprint pattern of RNase T1-resistant (T1) oligonucleotides that differed from those of two helper virus RNAs, and...

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

authors： Duesberg PH,Vogt PK

更新日期：1979-04-01 00:00:00

abstract：:Complex I functions as a redox-linked proton pump in the respiratory chains of mitochondria and bacteria, driven by the reduction of quinone (Q) by NADH. Remarkably, the distance between the Q reduction site and the most distant proton channels extends nearly 200 Å. To elucidate the molecular origin of this long-range...

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

authors： Sharma V,Belevich G,Gamiz-Hernandez AP,Róg T,Vattulainen I,Verkhovskaya ML,Wikström M,Hummer G,Kaila VR

更新日期：2015-09-15 00:00:00

abstract：:A detailed model for the structure and dynamics of the interior of the lipid bilayer in the liquid crystal phase is presented. The model includes two classes of motion: (i) the internal dynamics of the chains, determined from Brownian dynamics simulations with a continuous version of the Marcelja mean-field potential,...

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

authors： Pastor RW,Venable RM,Karplus M

更新日期：1991-02-01 00:00:00

abstract：:Bruton tyrosine kinase (EC 2.7.1.112) [Btk, encoded by Btk in mice and BTK in humans (formerly known as atk, BPK, or emb)], which is variously mutated in chromosome X-linked agammaglobulinemia patients and X-linked immunodeficient (xid) mice, has the pleckstrin homology (PH) domain at its amino terminus. The PH domain...

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

authors： Yao L,Kawakami Y,Kawakami T

更新日期：1994-09-13 00:00:00

abstract：:Pluripotency of embryonic stem (ES) cells is maintained by transcription factors that form a highly interconnected protein interaction network surrounding the homeobox protein Nanog. Enforced expression of Nanog in mouse ES (mES) cells promotes self-renewal and alleviates their requirement for leukemia inhibitory fact...

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

authors： Wang J,Levasseur DN,Orkin SH

更新日期：2008-04-29 00:00:00

abstract：:The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was recently shown to negatively regulate LPS-induced acute inflammatory responses. We previously observed that the metabolic thiol antioxidant alpha-lipoic acid (LA) inhibits LPS-induced expression of cellular adhesion molecules and adheren...

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

authors： Zhang WJ,Wei H,Hagen T,Frei B

更新日期：2007-03-06 00:00:00

abstract：:Unconventional myosin 15 is a molecular motor expressed in inner ear hair cells that transports protein cargos within developing mechanosensory stereocilia. Mutations of myosin 15 cause profound hearing loss in humans and mice; however, the properties of this motor and its regulation within the stereocilia organelle a...

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

authors： Bird JE,Takagi Y,Billington N,Strub MP,Sellers JR,Friedman TB

更新日期：2014-08-26 00:00:00

abstract：:Coxsackievirus causes severe disease in adult mice subjected to sustained post-weaning undernutrition (marasmus). Virus-infected marasmic mice have an increased incidence of mortality, severe lesions, and elevated and persistent viral in target organs. Transfer of immune lymphoid cells 30 min or 24 hr after viral chal...

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

authors： Woodruff JF,Woodruff JJ

更新日期：1971-09-01 00:00:00

abstract：:Embryos carrying null mutations of both retinoid X receptors alpha and beta (RXRalpha-/-/RXRbeta-/- mutants) were generated. These mutant embryos die between 9.5 and 10.5 days of gestation and display a wide range of abnormalities. The cause of the lethality appears to be the lack of formation of the labyrinthine zone...

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

authors： Wendling O,Chambon P,Mark M

更新日期：1999-01-19 00:00:00

abstract：:The transcription initiation site of the human ribosomal RNA gene (rDNA) was located by using the single-strand specific nuclease protection method and by determining the first nucleotide of the in vitro capped 45S preribosomal RNA. The sequence of 1,211 nucleotides surrounding the initiation site was determined. The ...

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

authors： Financsek I,Mizumoto K,Mishima Y,Muramatsu M

更新日期：1982-05-01 00:00:00

abstract：:We have noted consistent structural similarities among unrelated proteases. In comparison with other proteins of similar size, proteases have smaller than average surface areas, smaller radii of gyration, and higher C(alpha) densities. These findings imply that proteases are, as a group, more tightly packed than other...

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

authors： Stawiski EW,Baucom AE,Lohr SC,Gregoret LM

更新日期：2000-04-11 00:00:00

abstract：:Agents that act as anion channel blockers (ACBs) and do not permeate cells appear to inhibit exocytosis in platelets, parathyroid cells, and neutrophils. Based in large part on these observations, anion influx through plasma membrane channels has been considered a factor controlling cellular secretion, but there have ...

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

authors： Vostal JG,Reid DM,Jones CE,Shulman NR

更新日期：1989-08-01 00:00:00

abstract：:We have isolated a lymphoid cell line, MDS, from the pleural exudate of a patient with chronic myelomonocytic leukemia. The cells are biphenotypic, containing various T-cell and myeloid markers, and are surface negative for CD4 and CD8 but have low CD4 mRNA. The cells grow in suspension with a doubling time of 15 hr, ...

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

authors： Banerjee R,Bekesi JG,Tarcsafalvi A,Sperber K,Deak G,Choi HS,Paronetto F,Holland JF,Acs G

更新日期：1992-11-01 00:00:00

abstract：:Flowering time (FT) is the developmental transition coupling an internal genetic program with external local and seasonal climate cues. The genetic loci sensitive to predictable environmental signals underlie local adaptation. We dissected natural variation in FT across a new global diversity set of 473 unique accessi...

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

authors： Li Y,Huang Y,Bergelson J,Nordborg M,Borevitz JO

更新日期：2010-12-07 00:00:00

abstract：:T cells are essential for immune defenses against pathogens, such that viability of naïve T cells before antigen encounter is critical to preserve a polyclonal repertoire and prevent immunodeficiencies. The viability of naïve T cells before antigen recognition is ensured by IL-7, which drives expression of the prosurv...

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

authors： Miller ML,Mashayekhi M,Chen L,Zhou P,Liu X,Michelotti M,Tramontini Gunn N,Powers S,Zhu X,Evaristo C,Alegre ML,Molinero LL

更新日期：2014-05-20 00:00:00

abstract：:Thebaine, an intermediate of morphine biosynthesis in the poppy plant, Papaver somniferum, was transformed to oripavine, codeine, and morphine by rat liver, kidney, and brain microsomes in the presence of an NADPH-generating system. The formation of morphine, codeine, and oripavine was identified by a specific RIA, HP...

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

authors： Kodaira H,Spector S

更新日期：1988-02-01 00:00:00

abstract：:Coat components localize to specific membrane domains, where they sort selected transmembrane proteins. To study how clathrin coats are stabilized on such domains and to identify the protein networks involved, we combined proteomic screens and in vitro liposome-based assays that recapitulate the fidelity of protein so...

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

authors： Baust T,Czupalla C,Krause E,Bourel-Bonnet L,Hoflack B

更新日期：2006-02-28 00:00:00

abstract：:Basal ganglia-thalamocortical circuits are critical for motor control and motor learning. Classically, basal ganglia nuclei are thought to regulate motor behavior by increasing or decreasing cortical firing rates, and basal ganglia diseases are assumed to reflect abnormal overall activity levels. More recent studies s...

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

authors： Kojima S,Kao MH,Doupe AJ

更新日期：2013-03-19 00:00:00

abstract：:Much debate has revolved around the question of whether the mode of evolutionary and ecological turnover in the fossil record of African mammals was continuous or pulsed, and the degree to which faunal turnover tracked changes in global climate. Here, we assembled and analyzed large specimen databases of the fossil re...

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

authors： Bibi F,Kiessling W

更新日期：2015-08-25 00:00:00

abstract：:After endocytosis, transmembrane cargo reaches endosomes, where it encounters complexes dedicated to opposing functions: recycling and degradation. Microdomains containing endosomal sorting complexes required for transport (ESCRT)-0 component Hrs [hepatocyte growth factor-regulated tyrosine kinase substrate (HGRS-1) i...

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

authors： Norris A,Tammineni P,Wang S,Gerdes J,Murr A,Kwan KY,Cai Q,Grant BD

更新日期：2017-01-17 00:00:00

abstract：:The role of various adhesion molecules in lymphocyte homing to the brain and in inflammatory autoimmune disease of the central nervous system (CNS) was examined in mice. Activated T cell lines and clones expressed CD44 and integrin alpha4, but not L-selectin, and entered the CNS independent of their antigen specificit...

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

authors： Brocke S,Piercy C,Steinman L,Weissman IL,Veromaa T

更新日期：1999-06-08 00:00:00