Positive supercoiling of DNA greatly diminishes mRNA synthesis in yeast.

abstract：:The replication initiator proteins encoded by the pT181 and related plasmids have sequence-specific DNA binding and topoisomerase activities. These proteins create a site-specific nick in one strand of the DNA at the origin of replication that serves as a primer for the initiation of replication. To define the regions...

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

authors： Dempsey LA,Birch P,Khan SA

更新日期：1992-04-01 00:00:00

abstract：:We have found that three Escherichia coli heat shock proteins, DnaK (the hsp70 homolog), DnaJ, and GrpE, function in oriP1 DNA replication in vitro solely to activate DNA binding by the replication initiator protein RepA. Activation results from the conversion of P1 or P7 RepA dimers to monomers that bind with high af...

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

authors： Wickner S,Skowyra D,Hoskins J,McKenney K

更新日期：1992-11-01 00:00:00

abstract：:Cigarette smoke is the major cause of lung cancer, the leading cause of cancer death, and of chronic obstructive pulmonary disease, the fourth leading cause of death in the United States. Using high-density gene expression arrays, we describe genes that are normally expressed in a subset of human airway epithelial cel...

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

authors： Spira A,Beane J,Shah V,Liu G,Schembri F,Yang X,Palma J,Brody JS

更新日期：2004-07-06 00:00:00

abstract：:Although the mechanisms of anterior-posterior axis formation are well understood in Drosophila, both embryological and molecular studies suggest significant variation in the mechanisms generating this axis within the Insecta class as a whole. ...

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

authors： Patel NH

更新日期：2000-04-25 00:00:00

abstract：:An intense (up to 20 muA/cm(2)) steady electrical current enters the anterior or nurse cell end of the growing follicle (or oocyte-nurse cell complex) of the Cecropia moth and is balanced by a more diffuse current leaving elsewhere. In late growth stages, the total transfollicular current is about 100 nA. Moreover, a ...

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

authors： Jaffe LF,Woodruff RI

更新日期：1979-03-01 00:00:00

abstract：:The 5' flanking sequences and the intron of the mouse Hoxa-7 gene were searched for regulatory elements that can function in Drosophila. Only the intron is able to activate a lacZ fusion gene in various tissues of Drosophila embryos. This enhancer function requires a cluster of three homeodomain binding sites (HB1-ele...

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

authors： Haerry TE,Gehring WJ

更新日期：1996-11-26 00:00:00

abstract：:Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree grow...

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

authors： Shestakova TA,Gutiérrez E,Kirdyanov AV,Camarero JJ,Génova M,Knorre AA,Linares JC,Resco de Dios V,Sánchez-Salguero R,Voltas J

更新日期：2016-01-19 00:00:00

abstract：:cDNA libraries were constructed from pathogenic (HM-1:IMSS) and nonpathogenic (SAW 1734) isolates of Entamoeba histolytica. A cDNA clone (cEH-P1) specific for pathogenic amoebae was identified by screening with a pool of sera from patients with invasive amoebiasis that had been absorbed with nonpathogenic amoebae. Thi...

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

authors： Tannich E,Horstmann RD,Knobloch J,Arnold HH

更新日期：1989-07-01 00:00:00

abstract：:The commitment of differentiating cells to a specialized fate is fundamental to the correct assembly of tissues within a multicellular organism. Because commitment is often irreversible, entry into and progression through this phase of development must be tightly regulated. Under nitrogen-limiting conditions, the mult...

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

authors： Videau P,Rivers OS,Hurd K,Ushijima B,Oshiro RT,Ende RJ,O'Hanlon SM,Cozy LM

更新日期：2016-11-08 00:00:00

abstract：:Nonresolving chronic inflammation at the neoplastic site is consistently associated with promoting tumor progression and poor patient outcomes. However, many aspects behind the mechanisms that establish this tumor-promoting inflammatory microenvironment remain undefined. Using bladder cancer (BC) as a model, we found ...

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

authors： Cheah MT,Chen JY,Sahoo D,Contreras-Trujillo H,Volkmer AK,Scheeren FA,Volkmer JP,Weissman IL

更新日期：2015-04-14 00:00:00

abstract：:A density-shift method is described for analyzing insulin receptor synthesis and turnover in cultured cells labeled with "heavy" amino acids (2H, 13C, and 15N). Solubilized newly synthesized heavy and old "light" receptors are separated by isopycnic banding on CsCl gradients and then quantitated. Insulin receptor synt...

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

authors： Reed BC,Lane MD

更新日期：1980-01-01 00:00:00

abstract：:Bacterial proteins often localize to distinct sites within the cell, but the primary cues that dictate localization are largely unknown. Recent evidence has shown that positive membrane curvature can serve as a cue for localization of a peripheral membrane protein. Here we report that localization of the peripheral me...

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

authors： Ramamurthi KS,Losick R

更新日期：2009-08-11 00:00:00

abstract：:In regulating gene expression in mammalian tissues, steroid hormones bind to cytoplasmic receptors and the resulting complex associates with the nucleus. In an attempt to study this nuclear association under more precisely controlled conditions, we examined the binding of receptor-[(3)H]steroid complexes to isolated n...

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

authors： Higgins SJ,Rousseau GG,Baxter JD,Tomkins GM

更新日期：1973-12-01 00:00:00

abstract：:Pure water in a highly (1)H spin-polarized state is proposed as a contrast-agent-free contrast agent to visualize its macroscopic evolution in aqueous media by MRI. Remotely enhanced liquids for image contrast (RELIC) utilizes a (1)H signal of water that is enhanced outside the sample in continuous-flow mode and immed...

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

authors： McCarney ER,Armstrong BD,Lingwood MD,Han S

更新日期：2007-02-06 00:00:00

abstract：:The traG protein of the F sex factor is an inner membrane protein with a molecular weight of 116,000. Mutants in traG (or in traN) are able to trigger conjugal DNA replication even though they cannot efficiently form stable mating aggregates with F(-) cells. The traG protein (and the traN protein) probably acts in the...

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

authors： Manning PA,Morelli G,Achtman M

更新日期：1981-12-01 00:00:00

abstract：:Chromosome segregation and mitotic exit are initiated by the 1.2-MDa ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) and its coactivator CDC20 (cell division cycle 20). To avoid chromosome missegregation, APC/C(CDC20) activation is tightly controlled. CDC20 only associates with APC/C in mitosis when APC/...

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

authors： Qiao R,Weissmann F,Yamaguchi M,Brown NG,VanderLinden R,Imre R,Jarvis MA,Brunner MR,Davidson IF,Litos G,Haselbach D,Mechtler K,Stark H,Schulman BA,Peters JM

更新日期：2016-05-10 00:00:00

abstract：:Acetyl-CoA synthase from Clostridium thermoaceticum (ACS(Ct)) is an alpha(2)beta(2) tetramer containing two novel Ni-X-Fe(4)S(4) active sites (the A and C clusters) and a standard Fe(4)S(4) cluster (the B cluster). The acsA and acsB genes encoding the enzyme were cloned into Escherichia coli strain JM109 and overexpre...

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

authors： Loke HK,Bennett GN,Lindahl PA

更新日期：2000-11-07 00:00:00

abstract：:The gaseous phytohormone ethylene C(2)H(4) mediates numerous aspects of growth and development. Genetic analysis has identified a number of critical elements in ethylene signaling, but how these elements interact biochemically to transduce the signal from the ethylene receptor complex at the endoplasmic reticulum (ER)...

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

authors： Ju C,Yoon GM,Shemansky JM,Lin DY,Ying ZI,Chang J,Garrett WM,Kessenbrock M,Groth G,Tucker ML,Cooper B,Kieber JJ,Chang C

更新日期：2012-11-20 00:00:00

abstract：:Tolerance and resistance provide hosts with two distinct defense strategies against parasitism. In resistance the hosts "fight" the parasite directly, whereas in tolerance the hosts fight the disease by ameliorating the damage that infection causes. There is increasing recognition that the two mechanisms may exhibit v...

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

authors： Best A,White A,Boots M

更新日期：2008-12-30 00:00:00

abstract：:A biologically active vitamin D(3) metabolite ("peak V metabolite") more polar than 25-hydroxycholecalciferol has been isolated from chicken intestines in pure form as a mono(trimethylsilyl)ether derivative. The molecule has been identified as 1,25-dihydroxycholecalciferol by means of mass spectrometry, ultraviolet ab...

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

authors： Holick MF,Schnoes HK,DeLuca HF

更新日期：1971-04-01 00:00:00

abstract：:We report substantially improved performance of high-power quantum cascade lasers (QCLs) by using epitaxial-side-down mounting that provides superior heat dissipation properties. We used aluminum nitride as the heatsink material and gold-tin eutectic solder. We have obtained continuous wave power output of 450 mW at 2...

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

authors： Tsekoun A,Go R,Pushkarsky M,Razeghi M,Patel CK

更新日期：2006-03-28 00:00:00

abstract：:The kinetics of refolding of Escherichia coli dihydrofolate reductase (EC 1.5.1.3) have been examined upon dilution of unfolded enzyme in 4.5 M urea to 1.29 M urea in 0.02 M phosphate buffer (pH 7.2) at 10 degrees C. Changes in the intrinsic protein fluorescence on refolding are characterized by four phases. Based on ...

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

authors： Frieden C

更新日期：1990-06-01 00:00:00

abstract：:p300 acetylates and activates the tumor suppressor p53 after DNA damage. Here, we show that MDM2, a negative-feedback regulator of p53, inhibited p300-mediated p53 acetylation by complexing with these two proteins. First, we purified a p300-MDM2-p53 protein complex from HeLa nuclear extracts, which was inactive in p53...

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

authors： Kobet E,Zeng X,Zhu Y,Keller D,Lu H

更新日期：2000-11-07 00:00:00

abstract：:The thrombogenicity of three highly purified proteases (thrombin, activated Factor X, and activated Factor IX) was determined quantitatively in an animal model. The minimal amounts required to produce a standard score 4 thrombus were 1.1 nmol for thrombin, 0.12 nmol for activated Factor X, and 0.018 nmol for activated...

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

authors： Gitel SN,Stephenson RC,Wessler S

更新日期：1977-07-01 00:00:00

abstract：:The structures of the major folding intermediate, the transition state for folding, and the folded state of barnase have been previously characterized. We now add a further step toward a complete picture of the folding of barnase by reporting the backbone 15N, 13C, and 1H NMR assignments for barnase unfolded at pH 1.8...

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

authors： Arcus VL,Vuilleumier S,Freund SM,Bycroft M,Fersht AR

更新日期：1994-09-27 00:00:00

abstract：:Noncompliance with social distancing during the early stage of the coronavirus disease 2019 (COVID-19) pandemic poses a great challenge to the public health system. These noncompliance behaviors partly reflect people's concerns for the inherent costs of social distancing while discounting its public health benefits. W...

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

authors： Xie W,Campbell S,Zhang W

更新日期：2020-07-28 00:00:00

abstract：:Mechanical injury to the adult mammalian spinal cord results in permanent loss of structural integrity at the lesion site and of the brain-controlled function distal to the lesion. Some of these consequences were permanently averted by altering the cellular constituents at the lesion site with x-irradiation delivered ...

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

authors： Kalderon N,Fuks Z

更新日期：1996-10-01 00:00:00

abstract：:This work describes the rational design, synthesis, and study of a ligand that selectively complexes CUG repeats in RNA (and CTG repeats in DNA) with high nanomolar affinity. This sequence is considered a causative agent of myotonic dystrophy type 1 (DM1) because of its ability to sequester muscleblind-like (MBNL) pro...

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

authors： Arambula JF,Ramisetty SR,Baranger AM,Zimmerman SC

更新日期：2009-09-22 00:00:00

abstract：:Protein Hal is a human gamma4 heavy-chain disease protein whose molecular weight is reduced from 55,000 to 25,000 in 6 M guanidine due to the lack of disulfide bonds between heavy chains. Studies of aminoacid sequence indicate that it contains a gap of about 240 residues, starting 10 residues from the N-terminal end a...

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

authors： Frangione B,Lee L,Haber E,Bloch KJ

更新日期：1973-04-01 00:00:00

abstract：:In addition to their well-recognized hepatotropism, all hepatitis B viruses (HBVs) display marked species specificity, growing poorly or not at all in species other than those closely related to their natural hosts. We have examined the molecular basis for this narrow host range, using duck HBV (DHBV) and heron HBV (H...

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

authors： Ishikawa T,Ganem D

更新日期：1995-07-03 00:00:00