A single-stranded DNA-binding protein from Crithidia fasciculata recognizes the nucleotide sequence at the origin of replication of kinetoplast DNA minicircles.

abstract：:The opposite slopes of "Evolution Canyon" in Israel have served as a natural model system of adaptation to a microclimate contrast. Long-term studies of Drosophila melanogaster populations inhabiting the canyon have exhibited significant interslope divergence in thermal and drought stress resistance, candidate genes, ...

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

authors： Hübner S,Rashkovetsky E,Kim YB,Oh JH,Michalak K,Weiner D,Korol AB,Nevo E,Michalak P

更新日期：2013-12-24 00:00:00

abstract：:Nonenzymatic manganese was first shown to provide protection against superoxide toxicity in vivo in 1981, but the chemical mechanism responsible for this protection subsequently became controversial due to conflicting reports concerning the ability of Mn to catalyze superoxide disproportionation in vitro. In a recent ...

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

authors： Barnese K,Gralla EB,Valentine JS,Cabelli DE

更新日期：2012-05-01 00:00:00

abstract：:Infected-cell protein 4 (ICP4), the major regulatory protein specified by herpes simplex virus 1 in infected cells, binds to homologs of the sequence ATCGTCnnnnYCGRC (A sites, where n is any nucleotide, Y is a pyrimidine, and R is a purine) and to unrelated sequences for which no consensus sequence has been derived (B...

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

authors： Michael N,Roizman B

更新日期：1989-12-01 00:00:00

abstract：:We explore the question of what are the best ligands for macromolecular targets. A survey of experimental data on a large number of the strongest-binding ligands indicates that the free energy of binding increases with the number of nonhydrogen atoms with an initial slope of approximately -1.5 kcal/mol (1 cal = 4.18 J...

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

authors： Kuntz ID,Chen K,Sharp KA,Kollman PA

更新日期：1999-08-31 00:00:00

abstract：:The ever-increasing industrial demand for nylon-6 (polycaprolactam) necessitates the development of environmentally benign methods of producing its precursor, epsilon-caprolactam, from cyclohexanone. It is currently manufactured in two popular double-step processes, each of which uses highly aggressive reagents, and e...

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

authors： Thomas JM,Raja R

更新日期：2005-09-27 00:00:00

abstract：:A long (20-30 micrometer), wide (3-5 micrometer) microbial-mat bacterium from the Ebro Delta (Tarragona, Spain) was grown in mixed culture and videographed live. Intracellular elemental sulfur globules and unique cell termini were observed in scanning-electron-microprobe and transmission-electron micrographs. A polar ...

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

authors： Guerrero R,Haselton A,Solé M,Wier A,Margulis L

更新日期：1999-09-28 00:00:00

abstract：:Although tumor necrosis factor (TNF) and interleukin 1 (IL-1) affect many cell functions, the molecular mechanisms of TNF and IL-1 action are not understood. Our present study shows that exposure of human FS-4 fibroblasts to TNF or IL-1 caused a rapid accumulation of intracellular cAMP and an increase in protein kinas...

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

authors： Zhang YH,Lin JX,Yip YK,Vilcek J

更新日期：1988-09-01 00:00:00

abstract：:Following carcinogen exposure in vitro, normal rat tracheal epithelial cells are transformed in a multistage process in which the cultured cells become immortal and, ultimately, neoplastic. Five cell lines derived from tumors produced by neoplastically transformed rat tracheal epithelial cells were examined for the ex...

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

authors： Walker C,Nettesheim P,Barrett JC,Gilmer TM

更新日期：1987-04-01 00:00:00

abstract：:VEGF and angiopoietin-1 (Ang1) are two major angiogenic factors being investigated for the treatment of myocardial infarction (MI). Targeting VEGF and Ang1 expression in the ischemic myocardium can increase their local therapeutic effects and reduce possible adverse effects. Adeno-associated viral vectors (AAVs) expre...

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

authors： Tao Z,Chen B,Tan X,Zhao Y,Wang L,Zhu T,Cao K,Yang Z,Kan YW,Su H

更新日期：2011-02-01 00:00:00

abstract：:Tregs are essential for maintaining peripheral tolerance, and thus targeting these cells may aid in the treatment of autoimmunity and cancer by enhancing or reducing suppressive functions, respectively. Before these cells can be harnessed for therapeutic purposes, it is necessary to understand how they maintain tolera...

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

authors： Pabbisetty SK,Rabacal W,Volanakis EJ,Parekh VV,Olivares-Villagómez D,Cendron D,Boyd KL,Van Kaer L,Sebzda E

更新日期：2016-08-09 00:00:00

abstract：:Sea urchins are a major component of recent marine communities where they exert a key role as grazers and benthic predators. However, their impact on past marine organisms, such as crinoids, is hard to infer in the fossil record. Analysis of bite mark frequencies on crinoid columnals and comprehensive genus-level dive...

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

authors： Gorzelak P,Salamon MA,Baumiller TK

更新日期：2012-05-01 00:00:00

abstract：:We investigate the dynamics and spatial distribution of land use fragmentation in a rapidly urbanizing region of the United States to test key propositions regarding the evolution of sprawl. Using selected pattern metrics and data from 1973 and 2000 for the state of Maryland, we find significant increases in developed...

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

authors： Irwin EG,Bockstael NE

更新日期：2007-12-26 00:00:00

abstract：:We have shown recently that the temporal order of antioxidant consumption in human blood plasma exposed to a constant flux of aqueous peroxyl radicals is ascorbate = protein thiols greater than bilirubin greater than urate greater than alpha-tocopherol and that detectable lipid peroxidation starts only after ascorbate...

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

authors： Frei B,England L,Ames BN

更新日期：1989-08-01 00:00:00

abstract：:Human brain functional networks are embedded in anatomical space and have topological properties--small-worldness, modularity, fat-tailed degree distributions--that are comparable to many other complex networks. Although a sophisticated set of measures is available to describe the topology of brain networks, the selec...

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

authors： Vértes PE,Alexander-Bloch AF,Gogtay N,Giedd JN,Rapoport JL,Bullmore ET

更新日期：2012-04-10 00:00:00

abstract：:Nitric oxide (NO), synthesized from L-arginine by NO synthases (NOS), plays an essential role in the regulation of cerebrovascular tone. Adenoviral vectors have been widely used to transfer recombinant genes to different vascular beds. To determine whether the recombinant endothelial NOS (eNOS) gene can be delivered i...

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

authors： Chen AF,Jiang SW,Crotty TB,Tsutsui M,Smith LA,O'Brien T,Katusic ZS

更新日期：1997-11-11 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：:The design principles of spider dragline silk, nature's high-performance fiber, are still largely unknown, in particular for the noncrystalline glycine-rich domains, which form the bulk of the material. Here we apply two-dimensional solid-state NMR to determine the distribution of the backbone torsion angles (phi,psi)...

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

authors： van Beek JD,Hess S,Vollrath F,Meier BH

更新日期：2002-08-06 00:00:00

abstract：:The intracellular activation of trypsinogen, which is both pH- and calcium-dependent, is an important early step in the development of acute pancreatitis. The cellular compartment in which trypsinogen activation occurs currently is unknown. We therefore investigated the site of intracellular trypsinogen activation by ...

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

authors： Sherwood MW,Prior IA,Voronina SG,Barrow SL,Woodsmith JD,Gerasimenko OV,Petersen OH,Tepikin AV

更新日期：2007-03-27 00:00:00

abstract：:O(6)-methylguanine (O(6)meG) and related modifications of guanine in double-stranded DNA are functionally severe lesions that can be produced by many alkylating agents, including N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a potent carcinogen. O(6)meG is repaired through its demethylation by the O(6)-alkylguanine-DNA...

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

authors： Hwang CS,Shemorry A,Varshavsky A

更新日期：2009-02-17 00:00:00

abstract：:To generate antibodies with different effector functions, B cells undergo Immunoglobulin Heavy Chain (IgH) class switch recombination (CSR). The ligation step of CSR is usually mediated by the classical nonhomologous end-joining (cNHEJ) pathway. In cNHEJ-deficient cells, a remarkable ∼25% of CSR can be achieved by the...

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

authors： Wang XS,Zhao J,Wu-Baer F,Shao Z,Lee BJ,Cupo OM,Rabadan R,Gautier J,Baer R,Zha S

更新日期：2020-10-13 00:00:00

abstract：:The six-layered neocortex is a uniquely mammalian structure with evolutionary origins that remain in dispute. One long-standing hypothesis, based on similarities in neuronal connectivity, proposes that homologs of the layer 4 input and layer 5 output neurons of neocortex are present in the avian forebrain, where they ...

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

authors： Dugas-Ford J,Rowell JJ,Ragsdale CW

更新日期：2012-10-16 00:00:00

abstract：:The ability of the cornea to transmit light while being mechanically resilient is directly attributable to the formation of an extracellular matrix containing orthogonal sheets of collagen fibrils. The detailed structure of the fibrils and how this structure underpins the mechanical properties and organization of the ...

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

authors： Holmes DF,Gilpin CJ,Baldock C,Ziese U,Koster AJ,Kadler KE

更新日期：2001-06-19 00:00:00

abstract：:Tikal has long been viewed as one of the leading polities of the ancient Maya realm, yet how the city was able to maintain its substantial population in the midst of a tropical forest environment has been a topic of unresolved debate among researchers for decades. We present ecological, paleoethnobotanical, hydraulic,...

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

authors： Lentz DL,Dunning NP,Scarborough VL,Magee KS,Thompson KM,Weaver E,Carr C,Terry RE,Islebe G,Tankersley KB,Grazioso Sierra L,Jones JG,Buttles P,Valdez F,Ramos Hernandez CE

更新日期：2014-12-30 00:00:00

abstract：:Mutations in the visA gene of Escherichia coli cause the mutant bacteria to die upon illumination with visible light. We confirmed genetically that the visA gene is a structural gene for ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1). Since other mutations in the genes involved in the biosynthesis of heme can cur...

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

authors： Nakahigashi K,Nishimura K,Miyamoto K,Inokuchi H

更新日期：1991-12-01 00:00:00

abstract：:Polyclonal antibodies reactive with a cleavage site in human proinsulin (HPI) (C-peptide-A-chain junction) have been raised (rabbit, guinea pig) using a synthetic peptide antigen coupled with keyhole limpet hemocyanin. These antisera recognize native HPI and des-31,32-HPI equally well but react 20-50 times less well w...

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

authors： Steiner DF,Michael J,Houghten R,Mathieu M,Gardner PR,Ravazzola M,Orci L

更新日期：1987-09-01 00:00:00

abstract：:Activation of naïve cluster of differentiation (CD)8(+) cytotoxic T lymphocytes (CTLs) is a tightly regulated process, and specific dendritic cell (DC) subsets are typically required to activate naive CTLs. Potential pathways for antigen presentation leading to CD8(+) T-cell priming include direct presentation, cross-...

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

authors： Li L,Kim S,Herndon JM,Goedegebuure P,Belt BA,Satpathy AT,Fleming TP,Hansen TH,Murphy KM,Gillanders WE

更新日期：2012-07-31 00:00:00

abstract：:NMDA receptors are excitatory channels with critical functions in the physiology of central synapses. Their activation reaction proceeds as a series of kinetically distinguishable, reversible steps, whose structural bases are currently under investigation. Very likely, the earliest steps include glutamate binding to g...

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

authors： Iacobucci GJ,Wen H,Helou M,Liu B,Zheng W,Popescu GK

更新日期：2021-01-12 00:00:00

abstract：:The high susceptibility of human immunoglobulin D to proteolytic degradation affects its biological function, metabolism, and immunoassay. High-pressure liquid chromatography was used to investigate the mechanism and rate of limited proteolytic cleavage of IgD and also to identify, isolate, and quantify the reaction p...

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

authors： Ishioka N,Takahashi N,Putnam FW

更新日期：1987-01-01 00:00:00

abstract：:The spatial variations of the intricate cytoarchitecture, fluid scalae, and mechano-electric transduction in the mammalian cochlea have long been postulated to provide the organ with the ability to perform a real-time, time-frequency processing of sound. However, the precise manner by which this tripartite coupling en...

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

authors： Sasmal A,Grosh K

更新日期：2019-07-09 00:00:00

abstract：:Complementary DNA (cDNA) specific for chick globin mRNA sequences fails to hybridize to total RNA extracted from chicken fibroblasts. After infection by Rous sarcoma virus, RNA complementary to globin cDNA is detectable in 100-500 copies per cell. Infection of fibroblasts with the transformation defective (td) deletio...

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

authors： Groudine M,Weintraub H

更新日期：1975-11-01 00:00:00