Stimulation of release of adrenal catecholamine by adenosine 3':5'-cyclic monophosphate and theophylline in the absence of extracellular Ca 2+ .

abstract：:Branched polyethylenimine (PEI) chains with an average molecular mass of 2 kDa (PEI2) have been covalently attached to gold nanoparticles (GNPs), and the potency of the resulting PEI2-GNPs conjugates as vectors for the delivery of plasmid DNA into monkey kidney (COS-7) cells in the presence of serum in vitro has been ...

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

authors： Thomas M,Klibanov AM

更新日期：2003-08-05 00:00:00

abstract：:A transcription factor required for synthesis of accurately initiated run-off transcripts by RNA polymerase II has been purified and shown to have an associated DNA-dependent ATPase (dATPase) activity that is strongly stimulated by the TATA region of promoters. This transcription factor, designated delta, was purified...

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

authors： Conaway RC,Conaway JW

更新日期：1989-10-01 00:00:00

abstract：:Theories of evolution that state natural selection acts on individuals have been modified to include multiple levels of selection. Here we demonstrate in chimeric protochordates that primitive germ cell (pgc) and somatic cell (psc) lineages have traits that also make them likely units of natural selection. Specificall...

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

authors： Stoner DS,Rinkevich B,Weissman IL

更新日期：1999-08-03 00:00:00

abstract：:Although in decline after successful anti-HIV therapy, B-cell lymphomas are still elevated in HIV-1-seropositive (HIV+) persons, and the mechanisms are obscure. The HIV-1 matrix protein p17 persists in germinal centers long after HIV-1 drug suppression, and some p17 variants (vp17s) activate Akt signaling and promote ...

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

authors： Dolcetti R,Giagulli C,He W,Selleri M,Caccuri F,Eyzaguirre LM,Mazzuca P,Corbellini S,Campilongo F,Marsico S,Giombini E,Muraro E,Rozera G,De Paoli P,Carbone A,Capobianchi MR,Ippolito G,Fiorentini S,Blattner WA,Lu W,

更新日期：2015-11-17 00:00:00

abstract：:Magnetic interactions between dissolved oxygen and nitroxide radical spin probes lead to broadening of the ESR lines. We have used a closed-chamber method based on this property to determine the maximum rate of O2 uptake per cell (Vmax per cell) in cultured mammalian cells. A suitable spin probe and a cell suspension ...

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

authors： Lai CS,Hopwood LE,Hyde JS,Lukiewicz S

更新日期：1982-02-01 00:00:00

abstract：:The proliferation of non-neoplastic T lymphocytes is regulated, in part, by the coordinated expression of genes encoding T-cell growth factor (interleukin 2, IL2), IL2 receptors (IL2R), and transferrin receptors (TFR). In addition to growth factors and their receptors, protooncogenes may regulate lymphocyte proliferat...

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

authors： Reed JC,Alpers JD,Nowell PC,Hoover RG

更新日期：1986-06-01 00:00:00

abstract：:Eukaryotic cells respond to a variety of DNA insults by triggering a common signal transduction cascade, known as checkpoint response, which temporarily halts cell-cycle progression. Although the main players involved in the cascade have been identified, there is still uncertainty about the nature of the structures th...

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

authors： Marini F,Nardo T,Giannattasio M,Minuzzo M,Stefanini M,Plevani P,Muzi Falconi M

更新日期：2006-11-14 00:00:00

abstract：:A leading hypothesis explaining Phanerozoic mass extinctions and associated carbon isotopic anomalies is the emission of greenhouse, other gases, and aerosols caused by eruptions of continental flood basalt provinces. However, the necessary serial relationship between these eruptions, isotopic excursions, and extincti...

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

authors： Whiteside JH,Olsen PE,Eglinton T,Brookfield ME,Sambrotto RN

更新日期：2010-04-13 00:00:00

abstract：:A sensitive test for kinetic unfolding intermediates in ribonuclease A (EC 3.1.27.5) is performed under conditions where the enzyme unfolds slowly (10 degrees C, pH 8.0, 4.5 M guanidinium chloride). Exchange of peptide NH protons (2H-1H) is used to monitor structural opening of individual hydrogen bonds during unfoldi...

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

authors： Kiefhaber T,Baldwin RL

更新日期：1995-03-28 00:00:00

abstract：:Controversy remains over whether the cancer stem cell (CSC) theory applies to all tumors. To determine whether cells within a highly aggressive solid tumor are stochastically or hierarchically organized, we combined a reporter system where the nucleostemin (NS) promoter drives GFP expression (termed NS-GFP) with a mou...

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

authors： Tamase A,Muraguchi T,Naka K,Tanaka S,Kinoshita M,Hoshii T,Ohmura M,Shugo H,Ooshio T,Nakada M,Sawamoto K,Onodera M,Matsumoto K,Oshima M,Asano M,Saya H,Okano H,Suda T,Hamada J,Hirao A

更新日期：2009-10-06 00:00:00

abstract：:The induction of hemoglobin synthesis by dimethylsulfoxide in cells infected with Friend leukemia virus has been shown to depend on the number of cell divisions after the addition of the inducing agent. In asynchronous cultures the cells have a generation time of 24 hr, and hemoglobin synthesis occurs after 48 hr in t...

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

authors： McClintock PR,Papaconstantinou J

更新日期：1974-11-01 00:00:00

abstract：:Tobacco mosaic virus (TMV) RNA was encapsulated in large, unilamellar phospholipid vesicles (liposomes), and the encapsulated TMV RNA was shown to be infectious when incubated with tobacco protoplasts under appropriate conditions. Maximal virus production in protoplasts was observed after their incubation with TMV RNA...

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

authors： Fraley RT,Dellaporta SL,Papahadjopoulos D

更新日期：1982-03-01 00:00:00

abstract：:The central questions of bacterial ecology and evolution require a method to consistently demarcate, from the vast and diverse set of bacterial cells within a natural community, the groups playing ecologically distinct roles (ecotypes). Because of a lack of theory-based guidelines, current methods in bacterial systema...

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

authors： Koeppel A,Perry EB,Sikorski J,Krizanc D,Warner A,Ward DM,Rooney AP,Brambilla E,Connor N,Ratcliff RM,Nevo E,Cohan FM

更新日期：2008-02-19 00:00:00

abstract：:The rise of animals occurred during an interval of Earth history that witnessed dynamic marine redox conditions, potentially rapid plate motions, and uniquely large perturbations to global biogeochemical cycles. The largest of these perturbations, the Shuram carbon isotope excursion, has been invoked as a driving mech...

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

authors： Rooney AD,Cantine MD,Bergmann KD,Gómez-Pérez I,Al Baloushi B,Boag TH,Busch JF,Sperling EA,Strauss JV

更新日期：2020-07-21 00:00:00

abstract：:Calmodulin (CaM) is a second messenger protein that has evolved to bind tightly to a variety of targets and, as such, exhibits low binding specificity. We redesigned CaM by using a computational protein design algorithm to improve its binding specificity for one of its targets, smooth muscle myosin light chain kinase ...

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

authors： Shifman JM,Mayo SL

更新日期：2003-11-11 00:00:00

abstract：:Necessary conditions are derived for a spherical vortex in a perfect fluid to be stationary in the case when the velocities depend on a single surface harmonic. The motion is indeterminate unless an additional condition is imposed. In the case when this condition is incompressibility, the equations are solved, yieldin...

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

authors： Pekeris CL

更新日期：1972-09-01 00:00:00

abstract：:The regulatory mechanisms underlying the uptake and utilization of multiple types of carbohydrates in actinomycetes remain poorly understood. In this study, we show that GlnR (central regulator of nitrogen metabolism) serves as a universal regulator of nitrogen metabolism and plays an important, previously unknown rol...

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

authors： Liao CH,Yao L,Xu Y,Liu WB,Zhou Y,Ye BC

更新日期：2015-12-22 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

authors： Sutcliffe JG

更新日期：1978-08-01 00:00:00

abstract：:We show that an electric field can drive single-stranded RNA and DNA molecules through a 2.6-nm diameter ion channel in a lipid bilayer membrane. Because the channel diameter can accommodate only a single strand of RNA or DNA, each polymer traverses the membrane as an extended chain that partially blocks the channel. ...

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

authors： Kasianowicz JJ,Brandin E,Branton D,Deamer DW

更新日期：1996-11-26 00:00:00

abstract：:Muscular dystrophy is a general term encompassing muscle disorders that cause weakness and wasting, typically leading to premature death. Membrane instability, as a result of a genetic disruption within the dystrophin-glycoprotein complex (DGC), is thought to induce myofiber degeneration, although the downstream mecha...

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

authors： Millay DP,Goonasekera SA,Sargent MA,Maillet M,Aronow BJ,Molkentin JD

更新日期：2009-11-10 00:00:00

abstract：:A sensitive in vitro crosslinking technique using a photoactive derivative of the chimeric activator LexA-E2F-1 was used to identify yeast proteins that might influence the response of RNA polymerase II to transcriptional activators. We found that a novel yeast protein, Xtc1p, could be covalently crosslinked to the ac...

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

authors： Emili A,Kobayashi R,Ingles CJ

更新日期：1998-09-15 00:00:00

abstract：:The nucleosomal repeat lengths of bulk chromatin and the chromatin of transcriptionally active and inactive genes were analyzed in two mouse cell lines and adult mouse spleens. The adult beta-globin gene exhibits a nucleosomal repeat length approximately 11 base pairs longer than (i) an inactive embryonic globin gene,...

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

authors： Smith RD,Seale RL,Yu J

更新日期：1983-09-01 00:00:00

abstract：:The core protein of a small chondroitin/dermatan sulfate proteoglycan expressed by human fibroblasts and present in extracellular matrices in association with collagen has been cloned from a lambda gt11 fibroblast cDNA library. cDNA clones were isolated by use of antibodies specific for the intact proteoglycan and ant...

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

authors： Krusius T,Ruoslahti E

更新日期：1986-10-01 00:00:00

abstract：:The ATP-binding cassette (ABC) transporter of mitochondria (Atm1) mediates iron homeostasis in eukaryotes, while the prokaryotic homolog from Novosphingobium aromaticivorans (NaAtm1) can export glutathione derivatives and confer protection against heavy-metal toxicity. To establish the structural framework underlying ...

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

authors： Fan C,Kaiser JT,Rees DC

更新日期：2020-08-11 00:00:00

abstract：:Dimyristoyl lecithin liposomes, containing cytochrome b5 reductase (NADH:ferricytochrome b5 oxidoreductase, EC 1.6.2.2) and varying amounts of cytochrome b5, were used to measure flavoprotein catalysis alone and catalysis requiring electron transfer between the reductase and cytochrome as a function of temperature. Wh...

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

authors： Strittmatter P,Rogers MJ

更新日期：1975-07-01 00:00:00

abstract：:Enhanced ethylene production is an early response of plants to pathogen attack and has been associated with both resistance and susceptibility to disease. Tobacco plants were transformed with the mutant etr1-1 gene from Arabidopsis, conferring dominant ethylene insensitivity. Besides lacking known ethylene responses, ...

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

authors： Knoester M,van Loon LC,van den Heuvel J,Hennig J,Bol JF,Linthorst HJ

更新日期：1998-02-17 00:00:00

abstract：:Mosquito repellency data on acylpiperidines derived from the U.S. Department of Agriculture archives were modeled by using molecular descriptors calculated by CODESSA PRO software. An artificial neural network model was developed for the correlation of these archival results and used to predict the repellent activity ...

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

authors： Katritzky AR,Wang Z,Slavov S,Tsikolia M,Dobchev D,Akhmedov NG,Hall CD,Bernier UR,Clark GG,Linthicum KJ

更新日期：2008-05-27 00:00:00

abstract：:The RAD52 epistasis group genes are involved in homologous DNA recombination, and their primary structures are conserved from yeast to humans. Although biochemical studies have suggested that the fundamental mechanism of homologous DNA recombination is conserved from yeast to mammals, recent studies of vertebrate cell...

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

authors： Sonoda E,Takata M,Yamashita YM,Morrison C,Takeda S

更新日期：2001-07-17 00:00:00

abstract：:The mammalian AML/CBFalpha runt domain (RD) transcription factors regulate hematopoiesis and osteoblast differentiation. Like their Drosophila counterparts, most mammalian RD proteins terminate in a common pentapeptide, VWRPY, which serves to recruit the corepressor Groucho (Gro). Using a yeast two-hybrid assay, in vi...

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

authors： Levanon D,Goldstein RE,Bernstein Y,Tang H,Goldenberg D,Stifani S,Paroush Z,Groner Y

更新日期：1998-09-29 00:00:00

abstract：:The specificity with which the genetic code is read in protein synthesis, and with which other highly specific biosynthetic reactions take place, can be increased above the level available from free energy differences in intermediates or kinetic barriers by a process defined here as kinetic proofreading. A simple kine...

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

authors： Hopfield JJ

更新日期：1974-10-01 00:00:00