Suppression of an absolute defect in type IV pilus biogenesis by loss-of-function mutations in pilT, a twitching motility gene in Neisseria gonorrhoeae.

abstract：:Microtubule formation from lamb brain tubulin isolated by affinity chromatography and freed of exchangeable nucleotide requires GTP for maximal rate and extent of polymerization. The nucleotide analogs guanylylmethylenediphosphate and guanylylimidodiphosphate fail to replace GTP; in addition, neither the presence of m...

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

authors： Maccioni R,Seeds NW

更新日期：1977-02-01 00:00:00

abstract：:Some realistic galaxy models have been found to support discrete unstable spiral modes. Here, through the study of the relevant physical mechanisms and an extensive numerical investigation of the properties of the dominant modes in a wide class of galactic equilibria, we show how spiral structures are excited with dif...

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

authors： Haass J,Bertin G,Lin CC

更新日期：1982-06-01 00:00:00

abstract：:The pH gradient (delta pH) across the membrane of bovine neurohypophysial granules was estimated by using the [14C]methylamine partition technique. The granule membrane showed high permeability to sugars such as sucrose or sorbitol and to cations. Granules suspended in sucrose medium showed an acidic internal delta pH...

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

authors： Scherman D,Nordmann JJ

更新日期：1982-01-01 00:00:00

abstract：:Protein kinase C (PKC) and Syk protein tyrosine kinase play critical roles in immune cell activation including that through the high-affinity IgE receptor, FcepsilonRI. Mechanisms by which PKC activation leads to the activation of Ras, a family of GTPases essential for immune cell activation, have been elusive. We pre...

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

authors： Kawakami Y,Kitaura J,Yao L,McHenry RW,Kawakami Y,Newton AC,Kang S,Kato RM,Leitges M,Rawlings DJ,Kawakami T

更新日期：2003-08-05 00:00:00

abstract：:The strong consistency of least squares estimates in multiple regression models with independent errors is obtained under minimal assumptions on the design and weak moment conditions on the errors. ...

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

authors： Lai TL,Robbins H,Wei CZ

更新日期：1978-07-01 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：:In this study, we defined the role of peroxisome proliferator-activated receptor beta/delta (PPARdelta) in metabolic homeostasis by using subtype selective agonists. Analysis of rat L6 myotubes treated with the PPARdelta subtype-selective agonist, GW501516, by the Affymetrix oligonucleotide microarrays revealed that P...

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

authors： Tanaka T,Yamamoto J,Iwasaki S,Asaba H,Hamura H,Ikeda Y,Watanabe M,Magoori K,Ioka RX,Tachibana K,Watanabe Y,Uchiyama Y,Sumi K,Iguchi H,Ito S,Doi T,Hamakubo T,Naito M,Auwerx J,Yanagisawa M,Kodama T,Sakai J

更新日期：2003-12-23 00:00:00

abstract：:Quiescent BALB/c 3T3 cells exposed briefly to a platelet-derived growth factor (PDGF) become "competent" to replicate their DNA but do not "progress" into S phase unless incubated with growth factors contained in platelet-poor plasma. Plasma from hypophysectomized rats is deficient in progression activity; it does not...

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

authors： Stiles CD,Capone GT,Scher CD,Antoniades HN,Van Wyk JJ,Pledger WJ

更新日期：1979-03-01 00:00:00

abstract：:Significant attention has focused on the role of low-density lipoprotein (LDL) in the pathogenesis of atherosclerosis. However, recent advances have identified triglyceride-rich lipoproteins [e.g., very LDL (VLDL)] as independent risk predictors for this disease. We have previously demonstrated peroxisome proliferator...

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

authors： Lee CH,Kang K,Mehl IR,Nofsinger R,Alaynick WA,Chong LW,Rosenfeld JM,Evans RM

更新日期：2006-02-14 00:00:00

abstract：:Incorporation experiments with labeled sirohydrochlorin and trimethylisobacteriochlorin demonstrate that ring contraction in vivo to the corrin macrocycle of vitamin B12 liberates acetic acid. The C-20 atom of the precursors becomes the acetate carboxyl carbon. ...

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

authors： Battersby AR,Bushell MJ,Jones C,Lewis NG,Pfenninger A

更新日期：1981-01-01 00:00:00

abstract：:To improve the usefulness of in vivo mode for the investigation of the pathophysiology of human immunodeficiency virus (HIV) infection, we modified the construction of SCID mice implanted with human fetal thymus and liver (thy/liv-SCID-hu mice) so that the peripheral blood of the mice contained significant numbers of ...

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

authors： Kollmann TR,Pettoello-Mantovani M,Katopodis NF,Hachamovitch M,Rubinstein A,Kim A,Goldstein H

更新日期：1996-04-02 00:00:00

abstract：:Sessile marine organisms are prolific sources of biologically active natural products. However, these compounds are often found in highly variable amounts, with the abiotic and biotic factors governing their production remaining poorly understood. We present an approach that permits monitoring of in vivo natural produ...

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

authors： Esquenazi E,Jones AC,Byrum T,Dorrestein PC,Gerwick WH

更新日期：2011-03-29 00:00:00

abstract：:Listeriolysin O (LLO) is a cholesterol-dependent cytolysin that is an essential virulence factor of Listeria monocytogenes. LLO pore-forming activity is pH-dependent; it is active at acidic pH (<6), but not at neutral pH. In contrast to other pH-dependent toxins, we have determined that LLO pore-forming activity is co...

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

authors： Schuerch DW,Wilson-Kubalek EM,Tweten RK

更新日期：2005-08-30 00:00:00

abstract：:The proteasome is responsible for degradation of substrates of the ubiquitin pathway. 20S proteasomes are cylindrical particles with subunits arranged in a stack of four heptameric rings. The outer rings are composed of alpha subunits, and the inner rings are composed of beta subunits. A well-characterized archaeal pr...

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

authors： Arendt CS,Hochstrasser M

更新日期：1997-07-08 00:00:00

abstract：:It is suggested that active transport, muscle contraction, and ribosomal translocation may all make use of a common allosteric mechanism in which ATP or GTP serves as both the effector and substrate and in which a conformational change in a protein (enzyme) moves or exerts a force on a second ligand. The enzymatic spl...

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

authors： Hill TL

更新日期：1969-09-01 00:00:00

abstract：:Cellular senescence is defined by the limited proliferative capacity of normal cultured cells. Immortal cells overcome this regulation and proliferate indefinitively. One step in the immortalization process may be reactivation of telomerase activity, a ribonucleoprotein complex, which, by de novo synthesized telomeric...

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

authors： Härle-Bachor C,Boukamp P

更新日期：1996-06-25 00:00:00

abstract：:Ig class-switch recombination (CSR) is directed by the long and repetitive switch regions and requires activation-induced cytidine deaminase (AID). One of the conserved switch-region sequence motifs (AGCT) is a preferred site for AID-mediated DNA-cytosine deamination. By using somatic gene targeting and recombinase-me...

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

authors： Han L,Masani S,Yu K

更新日期：2011-07-12 00:00:00

abstract：:A single catalytic site model is proposed to account for the multiphasic kinetics of oxidation of ferrocytochrome c by cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1). This model involves nonproductive binding of substrate to sites near the catalytic site on cytochrome c oxidase for cytochro...

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

authors： Speck SH,Dye D,Margoliash E

更新日期：1984-01-01 00:00:00

abstract：:Let E and F be vector bundles and D:E --> F an operator of order k. We associate a sequence of invariants ((l))(D), l >/= 0 with D which generalize the concept of curvature in a natural way. In the case where D = D(theta) is the differential operator of a connection theta on a vector bundle E, ((1))(D(theta)) is the c...

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

authors： Knapp RE

更新日期：1973-03-01 00:00:00

abstract：:Larger brains have an increasingly folded cerebral cortex whose white matter scales up faster than the gray matter. Here we analyze the cellular composition of the subcortical white matter in 11 primate species, including humans, and one Scandentia, and show that the mass of the white matter scales linearly across spe...

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

authors： Herculano-Houzel S,Mota B,Wong P,Kaas JH

更新日期：2010-11-02 00:00:00

abstract：:Cell metastasis is a highly dynamic process that occurs in multiple steps. Understanding this process has been limited by the inability to visualize tumor cell behavior in real time by using animal models. Here, we employ translucent zebrafish and high-resolution confocal microscopy to study how human cancer cells inv...

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

authors： Stoletov K,Montel V,Lester RD,Gonias SL,Klemke R

更新日期：2007-10-30 00:00:00

abstract：:Large mandibular defects are clinically challenging to reconstruct due to the complex anatomy of the jaw and the limited availability of appropriate tissue for repair. We envision leveraging current advances in fabrication and biomaterials to create implantable devices that generate bone within the patients themselves...

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

authors： Tatara AM,Koons GL,Watson E,Piepergerdes TC,Shah SR,Smith BT,Shum J,Melville JC,Hanna IA,Demian N,Ho T,Ratcliffe A,van den Beucken JJJP,Jansen JA,Wong ME,Mikos AG

更新日期：2019-04-02 00:00:00

abstract：:The ability of polynucleotides or polynucleotide duplexes such as poly(I).poly(C) to induce interferon production is proposed to depend on the existence of certain stable glycosidic orientations. It appears that a slight increase in instability of 1--3 kcal/mole (1 cal = 4.184 J) in the conformational regions near 20 ...

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

authors： Miles DL,Miles DW,Eyring H

更新日期：1979-03-01 00:00:00

abstract：:Public responses where identical T cell receptors (TCRs) are clonally dominant and shared between different individuals are a common characteristic of CD8(+) T cell-mediated immunity. Focusing on TCR sharing, we analyzed approximately 3,400 TCR beta chains (TCRbetas) from mouse CD8(+) T cells responding to the influen...

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

authors： Venturi V,Kedzierska K,Price DA,Doherty PC,Douek DC,Turner SJ,Davenport MP

更新日期：2006-12-05 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

abstract：:Pseudomonas aeruginosa is an opportunistic pathogen that requires preexisiting epithelial injury to cause acute infections. We report that P. aeruginosa inhibits mammalian cytokinesis in a type III secretion system and exotoxin T (ExoT)-dependent manner. ExoT is a bifunctional type III secretion system effector protei...

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

authors： Shafikhani SH,Engel J

更新日期：2006-10-17 00:00:00

abstract：:The phosphodiester bond formation by DNA-dependent RNA-polymerase (RNA nucleotidyltransferase, nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) can in principle result in retention, inversion, or racemization of configuration at the alpha-phosphorus of the nucleoside 5'-triphosphate being polymerized. As...

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

authors： Eckstein F,Armstrong VW,Sternbach H

更新日期：1976-09-01 00:00:00

abstract：:Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth-ocean-atmosphere dynamic exchange of elements. The ratios' dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previ...

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

authors： Lebrato M,Garbe-Schönberg D,Müller MN,Blanco-Ameijeiras S,Feely RA,Lorenzoni L,Molinero JC,Bremer K,Jones DOB,Iglesias-Rodriguez D,Greeley D,Lamare MD,Paulmier A,Graco M,Cartes J,Barcelos E Ramos J,de Lara A,Sanchez-Lea

更新日期：2020-09-08 00:00:00

abstract：:Our understanding of the mechanisms of neural circuit assembly is far from complete. Identification of wiring molecules with novel mechanisms of action will provide insights into how complex and heterogeneous neural circuits assemble during development. In the Drosophila olfactory system, 50 classes of olfactory recep...

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

authors： Xie Q,Wu B,Li J,Xu C,Li H,Luginbuhl DJ,Wang X,Ward A,Luo L

更新日期：2019-08-06 00:00:00

abstract：:Mammalian CLC proteins function as Cl(-) channels or as electrogenic Cl(-)/H(+) exchangers and are present in the plasma membrane and intracellular vesicles. We now show that the ClC-6 protein is almost exclusively expressed in neurons of the central and peripheral nervous systems, with a particularly high expression ...

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

authors： Poët M,Kornak U,Schweizer M,Zdebik AA,Scheel O,Hoelter S,Wurst W,Schmitt A,Fuhrmann JC,Planells-Cases R,Mole SE,Hübner CA,Jentsch TJ

更新日期：2006-09-12 00:00:00