Bird song syntax: learned intraspecific variation is meaningful.

abstract：:Expression of amino acid biosynthesis genes in bacteria is often repressed when abundant supplies of the cognate amino acid are available. Repression of the Bacillus subtilis lysC gene by lysine was previously shown to occur at the level of premature termination of transcription. In this study we show that lysine dire...

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

authors： Grundy FJ,Lehman SC,Henkin TM

更新日期：2003-10-14 00:00:00

abstract：:We identify a gene, organ boundary1 (OBO1), by its unique pattern of enhancer- driven GFP expression at the boundaries between the apical meristems and lateral organs in Arabidopsis embryos, seedlings, and mature plants. OBO1 also is expressed at the root apical meristem and in distinct cell files surrounding this are...

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

authors： Cho E,Zambryski PC

更新日期：2011-02-01 00:00:00

abstract：:I measured the strength of interaction between a marine herbivore and its growing resource over a realistic range of absolute and relative abundances. The herbivores (hermit crabs: Pagurus spp.) have slow and/or weak functional and numerical responses to epiphytic diatoms (Isthmia nervosa), which show logistic growth ...

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

authors： Ruesink JL

更新日期：1998-06-09 00:00:00

abstract：:Salmonella enterica serovar Typhi can colonize the gallbladder and persist in an asymptomatic carrier state that is frequently associated with the presence of gallstones. We have shown that salmonellae form bile-mediated biofilms on human gallstones and cholesterol-coated surfaces in vitro. Here, we test the hypothesi...

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

authors： Crawford RW,Rosales-Reyes R,Ramírez-Aguilar Mde L,Chapa-Azuela O,Alpuche-Aranda C,Gunn JS

更新日期：2010-03-02 00:00:00

abstract：:An in vitro system [Weil, P. A., Luse, D. S., Segall, J. & Roeder, R. G. (1979) Cell 18, 469-484 and Manley, J. L., Fire, A., Cano, A., Sharp, P. A. & Gefter, M. L., (1980) Proc. Natl. Acad. Sci USA 77, 3855-3859] was adapted for studying initiation of transcription of the ovalbumin gene. The DNA template was a cloned...

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

authors： Tsai SY,Tsai MJ,O'Malley BW

更新日期：1981-02-01 00:00:00

abstract：:How truth wins in social groups is an important open problem. Classic experiments on social groups dealing with truth statement issues present mixed findings on the conditions of truth abandonment and reaching a consensus on the truth. No theory has been developed and evaluated that might integrate these findings with...

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

authors： Friedkin NE,Bullo F

更新日期：2017-10-24 00:00:00

abstract：:Geckos can run rapidly on walls and ceilings, requiring high friction forces (on walls) and adhesion forces (on ceilings), with typical step intervals of approximately 20 ms. The rapid switching between gecko foot attachment and detachment is analyzed theoretically based on a tape model that incorporates the adhesion ...

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

authors： Tian Y,Pesika N,Zeng H,Rosenberg K,Zhao B,McGuiggan P,Autumn K,Israelachvili J

更新日期：2006-12-19 00:00:00

abstract：:Genetic analysis for group selection is developed for the case of a biallelic locus (A, a) undergoing group selection of founder populations only. By contrast to R. Levins"E = E(x) models, extinction now depends on genetics at the propagule stage but acts uniformly on larger populations. Biological evidence supports t...

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

authors： Boorman SA

更新日期：1978-04-01 00:00:00

abstract：:Previous work identified the Rap1 GTPase-activating protein Sipa1 as a germ-line-encoded metastasis modifier. The bromodomain protein Brd4 physically interacts with and modulates the enzymatic activity of Sipa1. In vitro analysis of a highly metastatic mouse mammary tumor cell line ectopically expressing Brd4 demonstr...

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

authors： Crawford NP,Alsarraj J,Lukes L,Walker RC,Officewala JS,Yang HH,Lee MP,Ozato K,Hunter KW

更新日期：2008-04-29 00:00:00

abstract：:Antimicrobial peptides constitute an important component of the mammalian innate immune response. Several types of antimicrobial peptides, including the beta-defensins, are produced at epithelial surfaces in response to infectious threats. Here we show that a class of small molecules, including l-isoleucine and severa...

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

authors： Fehlbaum P,Rao M,Zasloff M,Anderson GM

更新日期：2000-11-07 00:00:00

abstract：:All vertebrate cells have been shown to contain a gene, sarc, that has some homology with the transforming gene of Rous sarcoma virus, src. We have compared the polypeptide products of the sarc gene, p60(sarc), of human, mouse, and chicken cells with the polymorphic polypeptide product of the src gene, p60(src), of se...

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

authors： Sefton BM,Hunter T,Beemon K

更新日期：1980-04-01 00:00:00

abstract：:Aliphatic hydrocarbons such as fatty alcohols and petroleum-derived alkanes have numerous applications in the chemical industry. In recent years, the renewable synthesis of aliphatic hydrocarbons has been made possible by engineering microbes to overaccumulate fatty acids. However, to generate end products with the de...

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

authors： Akhtar MK,Turner NJ,Jones PR

更新日期：2013-01-02 00:00:00

abstract：:The orphan nuclear receptor Nur77/N10 has recently been demonstrated to be involved in apoptosis of T cell hybridomas. We report here that chronic expression of Nur77/N10 in thymocytes of transgenic mice results in a dramatic reduction of CD4+CD8+ double-positive as well as CD4+CD8- and CD4-CD8+ single-positive cell p...

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

authors： Weih F,Ryseck RP,Chen L,Bravo R

更新日期：1996-05-28 00:00:00

abstract：:DEAD-box RNA helicase proteins use the energy of ATP hydrolysis to drive the unwinding of duplex RNA. However, the mechanism that couples ATP utilization to duplex RNA unwinding is unknown. We measured ATP utilization and duplex RNA unwinding by DbpA, a non-processive bacterial DEAD-box RNA helicase specifically activ...

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

authors： Henn A,Cao W,Licciardello N,Heitkamp SE,Hackney DD,De La Cruz EM

更新日期：2010-03-02 00:00:00

abstract：:The enzymic activity of acetylcholinesterase can be photoregulated through the mediation of photochromic inhibitors of the enzyme. N-p-phenylazophenyl-N-phenylcarbamyl fluoride, an irreversible inhibitor of acetylcholinesterase, exists as two geometric isomers which are interconvertible through the action of light. Th...

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

authors： Bieth J,Vratsanos SM,Wassermann N,Erlanger BF

更新日期：1969-11-01 00:00:00

abstract：:Climate change and resource exploitation have been shown to modify the importance of bottom-up and top-down forces in ecosystems. However, the resulting pattern of trophic control in complex food webs is an emergent property of the system and thus unintuitive. We develop a statistical nondeterministic model, capable o...

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

authors： Lynam CP,Llope M,Möllmann C,Helaouët P,Bayliss-Brown GA,Stenseth NC

更新日期：2017-02-21 00:00:00

abstract：:Trust is a critical social process that helps us to cooperate with others and is present to some degree in all human interaction. However, the underlying brain mechanisms of conditional and unconditional trust in social reciprocal exchange are still obscure. Here, we used hyperfunctional magnetic resonance imaging, in...

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

authors： Krueger F,McCabe K,Moll J,Kriegeskorte N,Zahn R,Strenziok M,Heinecke A,Grafman J

更新日期：2007-12-11 00:00:00

abstract：:Previous studies in Saccharomyces cerevisiae have defined an essential role for the Dbf4-Cdc7 kinase complex in the initiation of DNA replication presumably by phosphorylation of target proteins, such as the minichromosome maintenance (Mcm) complex. We have examined the phosphorylation of the Mcm complex by the Dfp1-H...

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

authors： Lee JK,Seo YS,Hurwitz J

更新日期：2003-03-04 00:00:00

abstract：:A Drosophila cDNA encoding a human transcription factor TFIIB homologue was isolated by PCR methods. The deduced amino acid sequence indicates 85% sequence similarity with human TFIIB, and the corresponding cDNA product expressed in Escherichia coli is interchangeable with human TFIIB for both basal and GAL4-VP16-indu...

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

authors： Yamashita S,Wada K,Horikoshi M,Gong DW,Kokubo T,Hisatake K,Yokotani N,Malik S,Roeder RG,Nakatani Y

更新日期：1992-04-01 00:00:00

abstract：:A diploid strain of yeast (Saccharomyces cerevisiae) was found to be heterozygous for two forms of the highly repetitious ribosomal DNA. These forms could be distinguished by the pattern of fragments produced after digestion with the site-specific restriction endonuclease EcoRI. The mode of inheritance of ribosomal DN...

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

authors： Petes TD,Botstein D

更新日期：1977-11-01 00:00:00

abstract：:Tomato plants overexpressing a prosystemin gene that encodes the precursor of a mobile wound signal called systemin have been shown previously to constitutively synthesize extraordinarily high levels of two defensive proteinase inhibitor proteins in leaves in the absence of wounding. We herein report that leaves of th...

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

authors： Constabel CP,Bergey DR,Ryan CA

更新日期：1995-01-17 00:00:00

abstract：:For beta-D-glucosylisophosphoramide mustard (beta-D-Glc-IPM), a new alkylating drug in which isophosphoramide mustard is stabilized, a higher selectivity and lower myelotoxicity was observed than for the currently used cytostatic ifosfamide. Because beta-D-Glc-IPM is hydrophilic and does not diffuse passively through ...

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

authors： Veyhl M,Wagner K,Volk C,Gorboulev V,Baumgarten K,Weber WM,Schaper M,Bertram B,Wiessler M,Koepsell H

更新日期：1998-03-17 00:00:00

abstract：:Models of the Fv portion (containing the variable regions of the heavy and light chains) of two monoclonal anti-alpha (1----6)dextran antibodies, W3129 and 19.1.2, were constructed from amino acid sequences and the known three-dimensional structures of the Fv portions of McPC603 and J539. The modeled combining site of...

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

authors： Padlan EA,Kabat EA

更新日期：1988-09-01 00:00:00

abstract：:Distinct subsets of thymic epithelial cells (TECs) support T-cell development and selection. Isolated TECs contain multicellular complexes that enclose many viable thymocytes. However, the functions of those TECs, termed thymic nurse cells (TNCs), are unclear and the idea that TNCs are present in vivo is questioned. H...

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

authors： Nakagawa Y,Ohigashi I,Nitta T,Sakata M,Tanaka K,Murata S,Kanagawa O,Takahama Y

更新日期：2012-12-11 00:00:00

abstract：:ATP and UTP can function as extracellular signaling molecules by activating plasma membrane receptors termed P2 purinergic receptors. In the present study a P2U receptor cDNA has been expressed in K-562 human leukemia cells, one of the few available mammalian cell lines that lacks an endogenous P2U receptor. In stably...

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

authors： Erb L,Lustig KD,Sullivan DM,Turner JT,Weisman GA

更新日期：1993-11-15 00:00:00

abstract：:We have examined the effect of diphtheria toxin, Pseudomonas aeruginosa exotoxin A, and cycloheximide on the CV-1 cell cytoskeleton. Within a few hours after producing an inhibition of cellular protein synthesis, all these agents specifically disrupted the organization of the vimentin filament system with no discernab...

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

authors： Sharpe AH,Chen LB,Murphy JR,Fields BN

更新日期：1980-12-01 00:00:00

abstract：:Plants produce a wide range of allelochemicals to defend against herbivore attack, and generalist herbivores have evolved mechanisms to avoid, sequester, or detoxify a broad spectrum of natural defense compounds. Successful arthropod pests have also developed resistance to diverse classes of pesticides and this adapta...

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

authors： Dermauw W,Wybouw N,Rombauts S,Menten B,Vontas J,Grbic M,Clark RM,Feyereisen R,Van Leeuwen T

更新日期：2013-01-08 00:00:00

abstract：:High-pressure methods are increasingly used to produce new dense materials with unusual properties. Increasing efforts to understand the reaction mechanisms at the microscopic level, to set up and optimize synthetic approaches, are currently directed at carbon-based solids. A fundamental, but still unsolved, question ...

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

authors： Citroni M,Bini R,Foggi P,Schettino V

更新日期：2008-06-03 00:00:00

abstract：:Suppressor T cells have been shown to be much more radiosensitive than other lymphoïd cells, and we have tried to reduce tumor growth by low-dose irradiation. Syngeneic DBA/2 mice received whole-body irradiation (150 rads; 1 rad = 0.01 J/kg) 6 days after P815 tumor inoculation. Tumor growth is significantly reduced in...

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

authors： Tilkin AF,Schaaf-Lafontaine N,Van Acker A,Boccadoro M,Urbain J

更新日期：1981-03-01 00:00:00

abstract：:The perceptual color qualities of hue, saturation, and brightness do not correspond in any simple way to the physical characteristics of retinal stimuli, a fact that poses a major obstacle for any explanation of color vision. Here we test the hypothesis that these basic color attributes are determined by the statistic...

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

authors： Long F,Yang Z,Purves D

更新日期：2006-04-11 00:00:00