Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases.

abstract：:The beta 2-adrenergic receptor (beta 2AR) can be constitutively activated by mutations in the third intracellular loop. Whereas the wild-type receptor exists predominantly in an inactive conformation (R) in the absence of agonist, the mutant receptor appears to spontaneously adopt an active conformation (R*). We now d...

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

authors： Pei G,Samama P,Lohse M,Wang M,Codina J,Lefkowitz RJ

更新日期：1994-03-29 00:00:00

abstract：:Endothelial cells (ECs) line the mammalian vascular system and respond to the hemodynamic stimulus of fluid shear stress, the frictional force produced by blood flow. When ECs are exposed to shear stress, one of the fastest responses is an increase of K(+) conductance, which suggests that ion channels are involved in ...

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

authors： Hoger JH,Ilyin VI,Forsyth S,Hoger A

更新日期：2002-05-28 00:00:00

abstract：:Heat shock factors (HSFs) are the master regulators of transcription under protein-damaging conditions, acting in an environment where the overall transcription is silenced. We determined the genomewide transcriptional program that is rapidly provoked by HSF1 and HSF2 under acute stress in human cells. Our results rev...

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

authors： Vihervaara A,Sergelius C,Vasara J,Blom MA,Elsing AN,Roos-Mattjus P,Sistonen L

更新日期：2013-09-03 00:00:00

abstract：:Columnar stromatolites were abundant and widespread in the Proterozoic but are exceedingly rare in modern seas. Consequently, the stromatolites at Hamelin Pool in Shark Bay, Western Australia, have been widely interpreted as unique modern analogs of ancient stromatolites constructed by complex communities of cyanobact...

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

authors： Awramik SM,Riding R

更新日期：1988-03-01 00:00:00

abstract：:Functional imaging of the human brain is an increasingly important technique for clinical and cognitive neuroscience research, with functional MRI (fMRI) of the blood oxygen level-dependent (BOLD) response and electroencephalography or magnetoencephalography (MEG) recordings of neural oscillations being 2 of the most ...

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

authors： Muthukumaraswamy SD,Edden RA,Jones DK,Swettenham JB,Singh KD

更新日期：2009-05-19 00:00:00

abstract：:A single, modified nucleoside in Escherichia coli tRNA, 6-(3-methyl-2-butenylamino)-2-methyl-thio-9-beta-D-ribofuranosylpurine, has been desulfurized with Raney nickel to afford its probable biosynthetic precursor. The limitations of the reaction at the nucleoside and tRNA levels and its lack of inhibition of the amin...

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

authors： Hecht SM,Kirkegaard LH,Bock RM

更新日期：1971-01-01 00:00:00

abstract：:Rift Valley fever (RVF) is a vector-borne viral disease widespread in Africa. The primary cycle involves mosquitoes and wild and domestic ruminant hosts. Humans are usually contaminated after contact with infected ruminants. As many environmental, agricultural, epidemiological, and anthropogenic factors are implicated...

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

authors： Lancelot R,Béral M,Rakotoharinome VM,Andriamandimby SF,Héraud JM,Coste C,Apolloni A,Squarzoni-Diaw C,de La Rocque S,Formenty PB,Bouyer J,Wint GR,Cardinale E

更新日期：2017-01-31 00:00:00

abstract：:We propose that retroviruses exploit a cell-encoded pathway of intercellular vesicle traffic, exosome exchange, for both the biogenesis of retroviral particles and a low-efficiency but mechanistically important mode of infection. This Trojan exosome hypothesis reconciles current paradigms of retrovirus-directed transm...

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

authors： Gould SJ,Booth AM,Hildreth JE

更新日期：2003-09-16 00:00:00

abstract：:A technique for systematic peptide variation by a combination of rational and evolutionary approaches is presented. The design scheme consists of five consecutive steps: (i) identification of a "seed peptide" with a desired activity, (ii) generation of variants selected from a physicochemical space around the seed pep...

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

authors： Schneider G,Schrödl W,Wallukat G,Müller J,Nissen E,Rönspeck W,Wrede P,Kunze R

更新日期：1998-10-13 00:00:00

abstract：:The 5' flanking sequences and the intron of the mouse Hoxa-7 gene were searched for regulatory elements that can function in Drosophila. Only the intron is able to activate a lacZ fusion gene in various tissues of Drosophila embryos. This enhancer function requires a cluster of three homeodomain binding sites (HB1-ele...

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

authors： Haerry TE,Gehring WJ

更新日期：1996-11-26 00:00:00

abstract：:The post-translational proteolytic conversion of somatostatin-14 precursors was studied to characterize the enzyme system responsible for the production of the tetradecapeptide either from its 15-kDa precursor protein or from its COOH-terminal fragment, somatostatin-28. A synthetic undecapeptide Pro-Arg-Glu-Arg-Lys-Al...

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

authors： Gluschankof P,Morel A,Gomez S,Nicolas P,Fahy C,Cohen P

更新日期：1984-11-01 00:00:00

abstract：:A mouse monoclonal antibody (7E6A5) of IgG isotype, reacting specifically with mucin-producing goblet cells of the human gastrointestinal tract, has been developed. 7E6A5 reacts by an ELISA with colonic protein eluted from a DEAE column. A screening by immunoperoxidase assay of 76 specimens from 19 different human tis...

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

authors： Vecchi M,Sakamaki S,Diamond B,Novikoff AB,Novikoff PM,Das KM

更新日期：1987-05-01 00:00:00

abstract：:A calmodulin-neomycin-resistance fusion gene was introduced into Trypanosoma brucei by electroporation, and stably transformed cell lines were obtained. In all of the transformants, the fusion gene had integrated into the host genome at the cognate locus, evidently by homologous recombination within flanking calmoduli...

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

authors： Eid J,Sollner-Webb B

更新日期：1991-03-15 00:00:00

abstract：:Humans' remarkable ability to quickly and accurately discriminate among thousands of highly similar complex objects demands rapid and precise neural computations. To elucidate the process by which this is achieved, we used magnetoencephalography to measure spatiotemporal patterns of neural activity with high temporal ...

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

authors： Vida MD,Nestor A,Plaut DC,Behrmann M

更新日期：2017-01-10 00:00:00

abstract：:The visual images in the eyes contain much more information than the brain can process. An important selection mechanism is feature-based attention (FBA). FBA is best described by attention filters that specify precisely the extent to which items containing attended features are selectively processed and the extent to...

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

authors： Sun P,Chubb C,Wright CE,Sperling G

更新日期：2016-10-25 00:00:00

abstract：:By adapting to sustained stimuli, hair cells in the internal ear retain their sensitivity to minute transient displacements. Because one model for adaptation asserts that this process is mediated by a myosin isozyme, we reasoned that we should be able to arrest adaptation by interfering with myosin's ATPase cycle thou...

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

authors： Gillespie PG,Hudspeth AJ

更新日期：1993-04-01 00:00:00

abstract：:Autocatalytic activation of an initiator caspase triggers the onset of apoptosis. In dying cells, caspase-9 activation is mediated by a multimeric adaptor complex known as the Apaf-1 apoptosome. The molecular mechanism by which caspase-9 is activated by the Apaf-1 apoptosome remains largely unknown. Here we demonstrat...

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

authors： Hu Q,Wu D,Chen W,Yan Z,Yan C,He T,Liang Q,Shi Y

更新日期：2014-11-18 00:00:00

abstract：:The symbiotic bacterium Wolbachia pipientis has been considered unique in its ability to cause multiple reproductive anomalies in its arthropod hosts. Here we report that an undescribed bacterium is vertically transmitted and associated with thelytokous parthenogenetic reproduction in Encarsia, a genus of parasitoid w...

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

authors： Zchori-Fein E,Gottlieb Y,Kelly SE,Brown JK,Wilson JM,Karr TL,Hunter MS

更新日期：2001-10-23 00:00:00

abstract：:A residual sphere is formed by projecting seismic ray travel-time anomalies, relative to a reference Earth model, onto an imaginary sphere around an earthquake. Any dominant slab-like fast band can be determined with spherical harmonic expansion. The technique is useful in detecting trends associated with high-velocit...

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

authors： Zhou HW,Anderson DL

更新日期：1989-11-01 00:00:00

abstract：:India's northward flight and collision with Asia was a major driver of global tectonics in the Cenozoic and, we argue, of atmospheric CO(2) concentration (pCO(2)) and thus global climate. Subduction of Tethyan oceanic crust with a carpet of carbonate-rich pelagic sediments deposited during transit beneath the high-pro...

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

authors： Kent DV,Muttoni G

更新日期：2008-10-21 00:00:00

abstract：:Oriented cell division is critical for cell fate specification, tissue organization, and tissue homeostasis, and relies on proper orientation of the mitotic spindle. The molecular mechanisms underlying the regulation of spindle orientation remain largely unknown. Herein, we identify a critical role for cylindromatosis...

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

authors： Yang Y,Liu M,Li D,Ran J,Gao J,Suo S,Sun SC,Zhou J

更新日期：2014-02-11 00:00:00

abstract：:If, because of trade-offs or similar considerations, components of fitness are negatively correlated in equilibrium populations, they may then exhibit no correlation with total fitness. Lack of correlation with fitness is a fundamental characteristic of selective neutrality. Hence, selectively important traits become ...

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

authors： Reeve R,Smith E,Wallace B

更新日期：1990-03-01 00:00:00

abstract：:Fungi that cause brown rot of wood are essential biomass recyclers and also the principal agents of decay in wooden structures, but the extracellular mechanisms by which they degrade lignocellulose remain unknown. To test the hypothesis that brown-rot fungi use extracellular free radical oxidants as biodegradative too...

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

authors： Kerem Z,Bao W,Hammel KE

更新日期：1998-09-01 00:00:00

abstract：:Tidal deltas are characterized by a dendritic network of distributaries that transport water and sediments to the ocean. Here, I show that the distributaries self-organize to uniformly redistribute the tidal prism across the entire delta system. The 2 opposite mechanisms of channel formation by avulsion and channel ab...

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

authors： Fagherazzi S

更新日期：2008-12-02 00:00:00

abstract：:The tumor promoter 12-O-tetra-decanoylphorbol-13-acetate (TPA) has been defined by its ability to promote tumorigenesis on carcinogen-initiated mouse skin. Activation of Wnt/β-catenin signaling has a decisive role in mouse skin carcinogenesis, but it remains unclear how TPA activates Wnt/β-catenin signaling in mouse s...

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

authors： Su Z,Song J,Wang Z,Zhou L,Xia Y,Yu S,Sun Q,Liu SS,Zhao L,Li S,Wei L,Carson DA,Lu D

更新日期：2018-08-07 00:00:00

abstract：:Soluble extracts of adenovirus-infected HeLa cell nuclei support DNA replication on exogenous adenovirus DNA templates. Conditions of synthesis using both wild-type and temperature-sensitive extracts have been defined. Nuclear extracts prepared from cells permissively infected with the adenovirus mutant H5ts125 expres...

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

authors： Kaplan LM,Ariga H,Hurwitz J,Horwitz MS

更新日期：1979-11-01 00:00:00

abstract：:Urinary acidification by the turtle bladder is due to a H+-ATPase that is located in the luminal membrane. The rate of H+ transport is stimulated by an increase in the ambient CO2. Using the fluorescent dye acridine orange, we showed that the mitochondria-rich cell of this equilibrium contains vesicles whose internal ...

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

authors： Gluck S,Cannon C,Al-Awqati Q

更新日期：1982-07-01 00:00:00

abstract：:Activation of androgen receptor (AR) via androgen in muscle cells has been closely linked to their growth and differentiation. Here, we report the cloning and characterization of supervillin (SV), a 205-kDa actin-binding protein, as an AR coregulator from the skeletal muscle cDNA library. Mammalian two-hybrid and glut...

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

authors： Ting HJ,Yeh S,Nishimura K,Chang C

更新日期：2002-01-22 00:00:00

abstract：:Although recent studies have shown that brown adipose tissue (BAT) arises from progenitor cells that also give rise to skeletal muscle, the developmental signals that control the formation of BAT remain largely unknown. Here, we show that brown preadipocytes possess primary cilia and can respond to Hedgehog (Hh) signa...

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

authors： Nosavanh L,Yu DH,Jaehnig EJ,Tong Q,Shen L,Chen MH

更新日期：2015-04-21 00:00:00

abstract：:Changes in climate during the 20th century differ from region to region across the United States. We provide strong evidence that spatial variations in US temperature trends are linked to the hydrologic cycle, and we also present unique information on the seasonal and latitudinal structure of the linkage. We show that...

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

authors： Portmann RW,Solomon S,Hegerl GC

更新日期：2009-05-05 00:00:00