East African megadroughts between 135 and 75 thousand years ago and bearing on early-modern human origins.

abstract：:Ubc13 is a ubiquitin-conjugating enzyme responsible for noncanonical ubiquitination of TNF receptor-associated factor (TRAF)-family adapter proteins involved in Toll-like receptor and TNF-family cytokine receptor signaling, which are regulators of innate immunity. Gene ablation was used to study the function of Ubc13 ...

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

authors： Fukushima T,Matsuzawa S,Kress CL,Bruey JM,Krajewska M,Lefebvre S,Zapata JM,Ronai Z,Reed JC

更新日期：2007-04-10 00:00:00

abstract：:In human adults, learning and memory under acute stress are characterized by an increased use of rigid habitual response strategies at the cost of flexible cognitive strategies. The immediate effects of stress on cognitive functioning early in life are not well understood. Here we show experimentally that acute stress...

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

authors： Seehagen S,Schneider S,Rudolph J,Ernst S,Zmyj N

更新日期：2015-10-13 00:00:00

abstract：:We describe the molecular cloning of various DNA segments generated by partial EcoRI endonuclease digestion of the sex factor F. These segments have been analyzed by agarose gel electrophoresis of EcoRI digests and were arranged in a series of overlapping fragments using the EcoRI fragment map of F established by H. O...

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

authors： Skurray RA,Nagaishi H,Clark AJ

更新日期：1976-01-01 00:00:00

abstract：:Inadequate resolution is the principal limitation of radiocarbon dating. However, recent work has shown that exact-year precision is attainable if use can be made of past increases in atmospheric radiocarbon concentration or so-called Miyake events. Here, this nascent method is applied to an archaeological site of pre...

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

authors： Kuitems M,Panin A,Scifo A,Arzhantseva I,Kononov Y,Doeve P,Neocleous A,Dee M

更新日期：2020-06-23 00:00:00

abstract：:Maintenance of genome stability is essential for the accurate propagation of genetic information and cell growth and survival. Organisms have therefore developed efficient strategies to prevent DNA lesions and rearrangements. Much of the information concerning these strategies has been obtained through the study of ba...

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

authors： Maréchal A,Parent JS,Véronneau-Lafortune F,Joyeux A,Lang BF,Brisson N

更新日期：2009-08-25 00:00:00

abstract：:The O(2) reduction site of cytochrome c oxidase (CcO), comprising iron (Fe(a3)) and copper (Cu(B)) ions, is probed by x-ray structural analyses of CO, NO, and CN(-) derivatives to investigate the mechanism of the complete reduction of O(2). Formation of the derivative contributes to the trigonal planar coordination of...

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

authors： Muramoto K,Ohta K,Shinzawa-Itoh K,Kanda K,Taniguchi M,Nabekura H,Yamashita E,Tsukihara T,Yoshikawa S

更新日期：2010-04-27 00:00:00

abstract：:Formulas are derived for the effect of size on a free-swimming microbe's ability to follow chemical, light, or temperature stimuli or to disperse in random directions. The four main assumptions are as follows: (i) the organisms can be modeled as spheres, (ii) the power available to the organism for swimming is proport...

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

authors： Dusenbery DB

更新日期：1997-09-30 00:00:00

abstract：:Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry. Recently, there has been a strong interest in understanding phenomena associated with the deposition of oxide nanoparticles on the surface of a second (host) oxide. Here, scanning tunneling microscop...

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

authors： Park JB,Graciani J,Evans J,Stacchiola D,Ma S,Liu P,Nambu A,Sanz JF,Hrbek J,Rodriguez JA

更新日期：2009-03-31 00:00:00

abstract：:Chemokines and their receptors are key factors in the onset and progression of AIDS. Among them, accumulating evidence strongly indicates the involvement of IL-8 and its receptors, CXCR1 and CXCR2, in AIDS-related conditions. Through extensive investigation of genetic variations of the human CXCR1-CXCR2 locus, we iden...

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

authors： Vasilescu A,Terashima Y,Enomoto M,Heath S,Poonpiriya V,Gatanaga H,Do H,Diop G,Hirtzig T,Auewarakul P,Lauhakirti D,Sura T,Charneau P,Marullo S,Therwath A,Oka S,Kanegasaki S,Lathrop M,Matsushima K,Zagury JF,Matsuda

更新日期：2007-02-27 00:00:00

abstract：:The charge density distribution of a protein has been refined experimentally. Diffraction data for a crambin crystal were measured to ultra-high resolution (0.54 A) at low temperature by using short-wavelength synchrotron radiation. The crystal structure was refined with a model for charged, nonspherical, multipolar a...

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

authors： Jelsch C,Teeter MM,Lamzin V,Pichon-Pesme V,Blessing RH,Lecomte C

更新日期：2000-03-28 00:00:00

abstract：:The TCR is an alpha beta heterodimer, a part of the multimeric structure through which physiological T-cell activation occurs. The expression of TCR alpha chain is greatly diminished in a beta-chain-deficient mutant Jurkat cell line (J.RT3-T3.5). The relationship between the expression of the TCR alpha and beta chains...

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

authors： Chung S,Strominger JL

更新日期：1995-04-25 00:00:00

abstract：:Linear porphyrin arrays self-assembled by either hydrogen bonding or metal ion coordination self-organize into lipid bilayer membranes. The length of the transmembrane assemblies is determined both by the thermodynamics of the intermolecular interactions in the supermolecule and by the dimension and physical chemical ...

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

authors： Drain CM

更新日期：2002-04-16 00:00:00

abstract：:The positive transcription elongation factor b (P-TEFb) is involved in physiological and pathological events including inflammation, cancer, AIDS, and cardiac hypertrophy. The balance between its active and inactive form is tightly controlled to ensure cellular integrity. We report that the transcriptional repressor C...

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

authors： Cherrier T,Le Douce V,Eilebrecht S,Riclet R,Marban C,Dequiedt F,Goumon Y,Paillart JC,Mericskay M,Parlakian A,Bausero P,Abbas W,Herbein G,Kurdistani SK,Grana X,Van Driessche B,Schwartz C,Candolfi E,Benecke AG,Van Lin

更新日期：2013-07-30 00:00:00

abstract：:Mutations of the VHL tumor suppressor gene occur in patients with VHL disease and in the majority of sporadic clear cell renal carcinomas (VHL(-/-) RCC). Loss of VHL protein function is associated with constitutive expression of mRNAs encoding hypoxia-inducible proteins, such as vascular endothelial growth factor. Ove...

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

authors： de Paulsen N,Brychzy A,Fournier MC,Klausner RD,Gnarra JR,Pause A,Lee S

更新日期：2001-02-13 00:00:00

abstract：:Human and murine MHC nonclassical class Ib-restricted invariant T (iT) cell subsets, such as invariant natural killer T cells (iNKT) and mucosal-associated invariant T cells, have specialized functions early in immune responses, especially in modulating subsequent adaptive immune responses. Here, we characterize a pro...

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

authors： Edholm ES,Albertorio Saez LM,Gill AL,Gill SR,Grayfer L,Haynes N,Myers JR,Robert J

更新日期：2013-08-27 00:00:00

abstract：:We have used the 1.1 kilobases of the 5' upstream region of the platelet factor four (PF4) gene coupled to the prokaryotic beta-galactosidase gene to generate two lines of transgenic mice that express this construct. Studies of blood, bone marrow, spleen, and thymus reveal that platelets are the only circulating blood...

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

authors： Ravid K,Beeler DL,Rabin MS,Ruley HE,Rosenberg RD

更新日期：1991-02-15 00:00:00

abstract：:To study the origin of and the degree of T-cell antigen receptor (TCR) diversity of Thy-1+ dendritic epidermal cells (Thy-1+ dECs) in mice, we have developed a monoclonal antibody (mAb 536) to the gamma delta TCR. mAb 536 binds to and stimulates interleukin 2 secretion from Thy-1+ dEC but not cells that express TCR co...

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

authors： Havran WL,Grell S,Duwe G,Kimura J,Wilson A,Kruisbeek AM,O'Brien RL,Born W,Tigelaar RE,Allison JP

更新日期：1989-06-01 00:00:00

abstract：:The isolation and biochemical properties of a Saccharomyces cerevisiae mutant (acc1-167) defective in acetyl-CoA carboxylase [acetyl-CoA:carbon-dioxide ligase (ADP forming), EC 6.4.1.2] activity are described. The mutant is deficient in de novo biosynthesis of long-chain fatty acids and specifically requires a saturat...

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

authors： Roggenkamp R,Numa S,Schweizer E

更新日期：1980-04-01 00:00:00

abstract：:The generation of diverse neuronal types and subtypes from multipotent progenitors during development is crucial for assembling functional neural circuits in the adult central nervous system. During mouse retinogenesis, early retinal progenitors give rise to several cell types, including ganglion, amacrine, horizontal...

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

authors： Luo H,Jin K,Xie Z,Qiu F,Li S,Zou M,Cai L,Hozumi K,Shima DT,Xiang M

更新日期：2012-02-28 00:00:00

abstract：:To visualize histone acetylation in living cells, we developed a genetically encoded fluorescent resonance energy transfer (FRET)-based indicator. Response of the indicator reflects changes in the acetylation state of both K5 and K8 in histone H4. Using this acetylation indicator, we were able to monitor the dynamic f...

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

authors： Sasaki K,Ito T,Nishino N,Khochbin S,Yoshida M

更新日期：2009-09-22 00:00:00

abstract：:Transforming growth factor-beta (TGFbeta) signaling has been shown to play a role in cardiac development as well as in the pathogenesis of cardiovascular disease. Prior studies have suggested a relationship between cholesterol metabolism and TGFbeta signaling. Here we demonstrate that induction of the cholesterol meta...

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

authors： Park HJ,Galper JB

更新日期：1999-09-28 00:00:00

abstract：:People who are more avoidant of pathogens are more politically conservative, as are nations with greater parasite stress. In the current research, we test two prominent hypotheses that have been proposed as explanations for these relationships. The first, which is an intragroup account, holds that these relationships ...

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

authors： Tybur JM,Inbar Y,Aarøe L,Barclay P,Barlow FK,de Barra M,Becker DV,Borovoi L,Choi I,Choi JA,Consedine NS,Conway A,Conway JR,Conway P,Adoric VC,Demirci DE,Fernández AM,Ferreira DC,Ishii K,Jakšić I,Ji T,van Leeuwen

更新日期：2016-11-01 00:00:00

abstract：:We prove that the property of excision in algebraic K-theory is for a Q-algebra A equivalent to the H-unitality of the latter. Our excision theorem, in particular, implies Karoubi's conjecture on the equality of algebraic and topological K-theory groups of stable C*-algebras. It also allows us to identify the algebrai...

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

authors： Suslin AA,Wodzicki M

更新日期：1990-12-15 00:00:00

abstract：:Macrophage migration inhibition factor (MIF) is one of a class of lymphocyte-derived mediator substances (lymphokines) which plays a role in the mechanism of cellular immunity. A variety of other soluble factors produced by non-lymphoid cells have been shown to have effects on macrophage mobility similar to that of MI...

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

authors： Yoshida T,Bigazzi P,Cohen S

更新日期：1975-04-01 00:00:00

abstract：:Bluetongue virus (BTV), a major threat to livestock, is a multilayered, nonturreted member of the Reoviridae, a family of segmented dsRNA viruses characterized by endogenous RNA transcription through an RNA-dependent RNA polymerase (RdRp). To date, the structure of BTV RdRp has been unknown, limiting our mechanistic u...

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

authors： He Y,Shivakoti S,Ding K,Cui Y,Roy P,Zhou ZH

更新日期：2019-08-13 00:00:00

abstract：:We have purified a protein from Necturus maculosus gallbladder cells that forms chloride channels in an artificial membrane. The same protein apparently can form channels that are highly selective for chloride but can have conductances varying from 9 to about 150 pS. The high-conductance channels are blocked by the mo...

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

authors： Finn AL,Dillard M,Gaido M

更新日期：1993-06-15 00:00:00

abstract：:We have studied a naturally occurring small-molecule antimitotic called diazonamide A. Diazonamide A is highly effective at blocking spindle assembly in mammalian cell culture and does so through a unique mechanism. A biotinylated form of diazonamide A affinity purifies ornithine delta-amino transferase (OAT), a mitoc...

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

authors： Wang G,Shang L,Burgett AW,Harran PG,Wang X

更新日期：2007-02-13 00:00:00

abstract：:The immunoglobulin heavy-chain-associated tetrapeptide, tuftsin (Thr-Lys-Pro-Arg), known for its phagocytosis-stimulating activity, was found to augment the antigen-specific, macrophage-dependent education of T lymphocytes. The investigation of stereospecific characteristics of the tetrapeptide, by use of structural a...

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

authors： Tzehoval E,Segal S,Stabinsky Y,Fridkin M,Spirer Z,Feldman M

更新日期：1978-07-01 00:00:00

abstract：:The Eemian (last interglacial, 130-115 ka) was likely the warmest of all interglacials of the last 800 ka, with summer Arctic temperatures 3-5 °C above present. Here, we present improved Eemian climate records from central Greenland, reconstructed from the base of the Greenland Ice Sheet Project 2 (GISP2) ice core. Ou...

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

authors： Yau AM,Bender ML,Robinson A,Brook EJ

更新日期：2016-08-30 00:00:00

abstract：:Fermions need to satisfy the Pauli exclusion principle: no two can be in the same state. This restriction is most compactly expressed in a second quantization formalism by the requirement that the creation and annihilation operators of the electrons satisfy anticommutation relations. The usual classical limit of quant...

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

authors： Levine RD

更新日期：2000-02-29 00:00:00