Negative selection imparts peptide specificity to the mature T cell repertoire.

abstract：:In 1950, Barbara McClintock published a Classic PNAS article, "The origin and behavior of mutable loci in maize," which summarized the evidence leading to her discovery of transposition. The article described a number of genome alterations revealed through her studies of the Dissociation locus, the first mobile geneti...

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

authors： Fedoroff NV

更新日期：2012-12-11 00:00:00

abstract：:DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate s...

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

authors： Marras AE,Zhou L,Su HJ,Castro CE

更新日期：2015-01-20 00:00:00

abstract：:The DEMETER (DME) DNA glycosylase initiates active DNA demethylation via the base-excision repair pathway and is vital for reproduction in Arabidopsis thaliana DME-mediated DNA demethylation is preferentially targeted to small, AT-rich, and nucleosome-depleted euchromatic transposable elements, influencing expression ...

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

authors： Park JS,Frost JM,Park K,Ohr H,Park GT,Kim S,Eom H,Lee I,Brooks JS,Fischer RL,Choi Y

更新日期：2017-02-21 00:00:00

abstract：:DNA fragmentation is a hallmark of apoptosis (programmed cell death). However, the biological function of apoptotic DNA fragmentation remains unclear. Here, we show that DNA fragmentation factor plays an important role for maintaining genomic stability. Inhibition or loss of the DNA fragmentation factor (DFF)/caspase-...

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

authors： Yan B,Wang H,Peng Y,Hu Y,Wang H,Zhang X,Chen Q,Bedford JS,Dewhirst MW,Li CY

更新日期：2006-01-31 00:00:00

abstract：:Cyanogen bromide fragments were isolated from the heavy chains of three human IgG myeloma proteins of the V(H)III subgroup, sequenced by an automated method, and localized to the variable region. Inspection of these sequences, together with corresponding stretches from both human and animal proteins (studied in other ...

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

authors： Kehoe JM,Capra JD

更新日期：1971-09-01 00:00:00

abstract：:Phosphatidylinositol (3,4,5)-triphosphate (PtdInsP(3)) mediates intracellular signaling for directional sensing and pseudopod extension at the leading edge of migrating cells during chemotaxis. How this PtdInsP(3) signal is translated into remodeling of the actin cytoskeleton is poorly understood. Here, using a proteo...

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

authors： Zhang P,Wang Y,Sesaki H,Iijima M

更新日期：2010-06-29 00:00:00

abstract：:Complement receptors (CRs), expressed notably on myeloid and lymphoid cells, play an essential function in the elimination of complement-opsonized pathogens and apoptotic/necrotic cells. In addition, these receptors are crucial for the cross-talk between the innate and adaptive branches of the immune system. CR3 (also...

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

authors： Bajic G,Yatime L,Sim RB,Vorup-Jensen T,Andersen GR

更新日期：2013-10-08 00:00:00

abstract：:Under conditions (0.2% CO2; 1% O2) that allow high rates of photosynthesis, chlorophyll fluorescence was measured simultaneously with carbon assimilation at various light intensities in spinach (Spinacia oleracea) leaves. Using a stoichiometry of 3 ATP/CO2 and the known relationship between ATP synthesis rate and driv...

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

authors： Schönknecht G,Neimanis S,Katona E,Gerst U,Heber U

更新日期：1995-12-19 00:00:00

abstract：:Use-dependent long-term changes of neuronal response properties must be gated to prevent irrelevant activity from inducing inappropriate modifications. Here we test the hypothesis that local network dynamics contribute to such gating. As synaptic modifications depend on temporal contiguity between presynaptic and post...

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

authors： Galuske RAW,Munk MHJ,Singer W

更新日期：2019-11-12 00:00:00

abstract：:Although introduced hemosporidian (malaria) parasites (Apicomplexa: Haemosporida) have hastened the extinction of endemic bird species in the Hawaiian Islands and perhaps elsewhere, little is known about the temporal dynamics of endemic malaria parasite populations. Haemosporidian parasites do not leave informative fo...

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

authors： Soares L,Latta SC,Ricklefs RE

更新日期：2017-06-20 00:00:00

abstract：:With continued debate over the functional significance of adult neurogenesis, identifying an in vivo correlate of neurogenesis has become an important goal. Here we rely on the coupling between neurogenesis and angiogenesis and test whether MRI measurements of cerebral blood volume (CBV) provide an imaging correlate o...

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

authors： Pereira AC,Huddleston DE,Brickman AM,Sosunov AA,Hen R,McKhann GM,Sloan R,Gage FH,Brown TR,Small SA

更新日期：2007-03-27 00:00:00

abstract：:Electrical coupling between pyramidal cell axons, and between interneuron dendrites, have both been described in the hippocampus. What are the functional roles of the two types of coupling? Interneuron gap junctions enhance synchrony of gamma oscillations (25-70 Hz) in isolated interneuron networks and also in network...

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

authors： Traub RD,Pais I,Bibbig A,LeBeau FE,Buhl EH,Hormuzdi SG,Monyer H,Whittington MA

更新日期：2003-02-04 00:00:00

abstract：:Translocations involving c-myc and an Ig locus have been reported rarely in human multiple myeloma (MM). Using specific fluorescence in situ hybridization probes, we show complex karyotypic abnormalities of the c-myc or L-myc locus in 19 of 20 MM cell lines and approximately 50% of advanced primary MM tumors. These ab...

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

authors： Shou Y,Martelli ML,Gabrea A,Qi Y,Brents LA,Roschke A,Dewald G,Kirsch IR,Bergsagel PL,Kuehl WM

更新日期：2000-01-04 00:00:00

abstract：:Nature is rife with networks that are functionally optimized to propagate inputs to perform specific tasks. Whether via genetic evolution or dynamic adaptation, many networks create functionality by locally tuning interactions between nodes. Here we explore this behavior in two contexts: strain propagation in mechanic...

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

authors： Rocks JW,Ronellenfitsch H,Liu AJ,Nagel SR,Katifori E

更新日期：2019-02-12 00:00:00

abstract：:Diabetic peripheral neuropathy (DPN) is the most common complication in both type 1 and type 2 diabetes. Here we studied some phenotypic features of a well-established animal model of type 2 diabetes, the leptin receptor-deficient db(-)/db(-) mouse, and also the effect of long-term (6 mo) treatment with coenzyme Q10 (...

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

authors： Shi TJ,Zhang MD,Zeberg H,Nilsson J,Grünler J,Liu SX,Xiang Q,Persson J,Fried KJ,Catrina SB,Watanabe M,Arhem P,Brismar K,Hökfelt TG

更新日期：2013-01-08 00:00:00

abstract：:To investigate how cell population density influences the intracellular concentration of cyclic AMP we have measured adenylate cyclase and cyclic AMP phosphodiesterase activities and cyclic AMP levels at various stages of cell density in normal rat-kidney (NRK) cells, which exhibit contact-inhibition of growth, and in...

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

authors： Anderson WB,Russell TR,Carchman RA,Pastan I

更新日期：1973-12-01 00:00:00

abstract：:An equation for the bond angles OC-M-CO for tetracarbonyl groups in which the transition metal atom M is enneacovalent, derived from the simple theory of hybrid sp(3)d(5) bond orbitals, is tested by comparison of the calculated values of the angles with the experimental values reported for many compounds containing M(...

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

authors： Pauling L

更新日期：1978-02-01 00:00:00

abstract：:The exopolysaccharide alginate is a major virulence factor in the pathogenicity of Pseudomonas aeruginosa infecting the lungs of cystic fibrosis (CF) patients. Alginate synthesis by P. aeruginosa is believed to occur in response to environmental signals present in the CF lung. Transcription of a critical alginate bios...

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

authors： Roychoudhury S,Sakai K,Chakrabarty AM

更新日期：1992-04-01 00:00:00

abstract：:The paucity of integral membrane protein structures creates a major bioinformatics gap, whose origin is the difficulty of crystallizing these detergent-solubilized proteins. The problem is particularly formidable for hetero-oligomeric integral membrane proteins, where crystallization is impeded by the heterogeneity an...

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

authors： Zhang H,Kurisu G,Smith JL,Cramer WA

更新日期：2003-04-29 00:00:00

abstract：:A glycoprotein was isolated and purified to homogeneity from the serum of a patient with chronic non-A, non-B hepatitis. NaDodSO4/PAGE of the glycoprotein revealed a single major band at Mr approximately 77,000. Antibodies to this glycoprotein were shown to possess the following immunoreactivity: (i) they reacted by r...

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

authors： Seto B,Gerety RJ

更新日期：1985-08-01 00:00:00

abstract：:The plasmid construct pSVO-CAT has been used to test adenovirus promoter activities in the unmethylated or methylated state. We have now observed that the E2A late promoter of adenovirus type 2 (Ad2) DNA also activated the chloramphenicol acetyltransferase (CAT) gene upon transfection of the pAd2E2A-CAT construct into...

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

authors： Langner KD,Weyer U,Doerfler W

更新日期：1986-03-01 00:00:00

abstract：:The study of gene family members has been aided by the isolation of related genes on the basis of DNA homology. We have adapted the polymerase chain reaction to screen animal genomes very rapidly and reliably for likely gene family members. Using conserved amino acid sequences to design degenerate oligonucleotide prim...

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

authors： Kamb A,Weir M,Rudy B,Varmus H,Kenyon C

更新日期：1989-06-01 00:00:00

abstract：:The response of forests to climate change depends in part on whether the photosynthetic benefit from increased atmospheric CO2 (∆Ca = future minus historic CO2) compensates for increased physiological stresses from higher temperature (∆T). We predicted the outcome of these competing responses by using optimization the...

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

authors： Sperry JS,Venturas MD,Todd HN,Trugman AT,Anderegg WRL,Wang Y,Tai X

更新日期：2019-12-17 00:00:00

abstract：:The nodZ gene, which is present in various soil bacteria such as Bradyrhizobium japonicum, Azorhizobium caulinodans, and Rhizobium loti, is involved in the addition of a fucosyl residue to the reducing N-acetylglucosamine residue of lipochitin oligosaccharide (LCO) signal molecules. Using an Escherichia coli strain th...

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

authors： Quinto C,Wijfjes AH,Bloemberg GV,Blok-Tip L,López-Lara IM,Lugtenberg BJ,Thomas-Oates JE,Spaink HP

更新日期：1997-04-29 00:00:00

abstract：:Communities have an important role to play in biodiversity conservation. However, community-based conservation as a panacea, like government-based conservation as a panacea, ignores the necessity of managing commons at multiple levels, with vertical and horizontal interplay among institutions. The study of conservatio...

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

authors： Berkes F

更新日期：2007-09-25 00:00:00

abstract：:This article addresses the need for new data on indirect effects of natural and anthropogenic aerosol particles on atmospheric ice clouds. Simultaneous measurements of the concentration and composition of tropospheric aerosol particles capable of initiating ice in cold (cirrus) clouds are reported. Measurements suppor...

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

authors： DeMott PJ,Cziczo DJ,Prenni AJ,Murphy DM,Kreidenweis SM,Thomson DS,Borys R,Rogers DC

更新日期：2003-12-09 00:00:00

abstract：:The nuclear envelope is a unique topological structure formed by lipid membranes in eukaryotic cells. Unlike other membrane structures, the nuclear envelope comprises two concentric membrane shells fused at numerous sites with toroid-shaped pores that impart a "geometric" genus on the order of thousands. Despite the i...

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

authors： Torbati M,Lele TP,Agrawal A

更新日期：2016-10-04 00:00:00

abstract：:The molecular weight of the major glycoprotein from the human erythrocyte membrane is 29,000, of which 55% is carbohydrate and 45% is protein. The binding of sodium dodecyl sulfate to this glycoprotein is anomalous when compared to water soluble proteins and leads to migration rates in sodium dodecyl sulfate-polyacryl...

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

authors： Grefrath SP,Reynolds JA

更新日期：1974-10-01 00:00:00

abstract：:The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a funct...

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

authors： Yosef I,Manor M,Kiro R,Qimron U

更新日期：2015-06-09 00:00:00

abstract：:The "disease-specific" (dsp) region next to the hrp gene cluster of Erwinia amylovora is required for pathogenicity but not for elicitation of the hypersensitive reaction. A 6.6-kb apparent operon, dspEF, was found responsible for this phenotype. The operon contains genes dspE and dspF and is positively regulated by h...

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

authors： Bogdanove AJ,Kim JF,Wei Z,Kolchinsky P,Charkowski AO,Conlin AK,Collmer A,Beer SV

更新日期：1998-02-03 00:00:00