DnaJ, DnaK, and GrpE heat shock proteins are required in oriP1 DNA replication solely at the RepA monomerization step.

abstract：:We have located a positive, cis-acting DNA sequence element within the 5' flanking DNA of the c-myc gene (-125 base pairs). This DNA sequence element has a large purine-pyrimidine strand asymmetry and can assume the H-DNA conformation. A factor with the properties of a ribonucleoprotein (RNP) interacts with this DNA r...

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

authors： Davis TL,Firulli AB,Kinniburgh AJ

更新日期：1989-12-01 00:00:00

abstract：:Thalassemia is a heritable human anemia caused by a variety of mutations that affect expression of the alpha- or the beta-chain of hemoglobin. The expressivity of the phenotype is likely to be influenced by unlinked modifying genes. Indeed, by using a mouse model of alpha-thalassemia, we find that its phenotype is str...

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

authors： Leder A,Wiener E,Lee MJ,Wickramasinghe SN,Leder P

更新日期：1999-05-25 00:00:00

abstract：:A critique is presented of the Lumsden-Wilson theory [Lumsden, C. J. & Wilson, E. O. (1980) Proc. Natl. Acad. Sci. USA 77, 4382-4386] of the transmission of cultural traits. An analysis of the underlying assumptions and the mathematical nature of the theory clarifies its essentially reductionist and determinist qualit...

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

authors： Alper JS,Lange RV

更新日期：1981-06-01 00:00:00

abstract：:We used a model system of purified components to explore the effects of a downstream target on the signaling properties of a covalent modification cycle, an example of retroactivity. In the experimental system used, a bifunctional enzyme catalyzed the modification and demodification of its substrate protein, with both...

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

authors： Ventura AC,Jiang P,Van Wassenhove L,Del Vecchio D,Merajver SD,Ninfa AJ

更新日期：2010-06-01 00:00:00

abstract：:Like all aliphatic amines, the polyamines spermine and spermidine are physical quenchers of singlet molecular oxygen (1O2*). The rate constants of these processes were determined in vitro with photochemically generated 1O2* and the hydrocarbon rubrene as substrate, in pyridine. At millimolar concentration, spermine an...

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

authors： Khan AU,Mei YH,Wilson T

更新日期：1992-12-01 00:00:00

abstract：:Microstructural, δ(13)C isotope and C/N ratio investigations were conducted on excavated material from the black Younger Dryas boundary in Lommel, Belgium, aiming for a characterisation of the carbon content and structures. Cubic diamond nanoparticles are found in large numbers. The larger ones with diameters around o...

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

authors： Tian H,Schryvers D,Claeys P

更新日期：2011-01-04 00:00:00

abstract：:Individuals with developmental dyslexia vary in their ability to improve reading skills, but the brain basis for improvement remains largely unknown. We performed a prospective, longitudinal study over 2.5 y in children with dyslexia (n = 25) or without dyslexia (n = 20) to discover whether initial behavioral or brain...

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

authors： Hoeft F,McCandliss BD,Black JM,Gantman A,Zakerani N,Hulme C,Lyytinen H,Whitfield-Gabrieli S,Glover GH,Reiss AL,Gabrieli JD

更新日期：2011-01-04 00:00:00

abstract：:We compared private and social decision making to investigate the neural underpinnings of the effect of social comparison on risky choices. We measured brain activity using functional MRI while participants chose between two lotteries: in the private condition, they observed the outcome of the unchosen lottery, and in...

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

authors： Bault N,Joffily M,Rustichini A,Coricelli G

更新日期：2011-09-20 00:00:00

abstract：:Many higher level avian clades are restricted to Earth's lower latitudes, leading to historical biogeographic reconstructions favoring a Gondwanan origin of crown birds and numerous deep subclades. However, several such "tropical-restricted" clades (TRCs) are represented by stem-lineage fossils well outside the ranges...

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

authors： Saupe EE,Farnsworth A,Lunt DJ,Sagoo N,Pham KV,Field DJ

更新日期：2019-06-25 00:00:00

abstract：:Because neurogenesis persists in the adult mammalian brain and can be regulated by physiological and pathological events, we investigated its possible involvement in the brain's response to focal cerebral ischemia. Ischemia was induced by occlusion of the middle cerebral artery in the rat for 90 min, and proliferating...

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

authors： Jin K,Minami M,Lan JQ,Mao XO,Batteur S,Simon RP,Greenberg DA

更新日期：2001-04-10 00:00:00

abstract：:A rice Dwarf 1 gene was identified by using a map-based cloning strategy. Its recessive mutant allele confers a dwarf phenotype. Linkage analysis revealed that a cDNA encoding the alpha-subunit of GTP-binding protein cosegregated with d1 in 3,185 d1 segregants. Southern hybridization analysis with this cDNA as a probe...

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

authors： Ashikari M,Wu J,Yano M,Sasaki T,Yoshimura A

更新日期：1999-08-31 00:00:00

abstract：:A stable free-radical polymeric derivative of prostaglandin B1 (PGBx) has been synthesized that exhibits regenerative effects on oxidative phosphorylation in aged mitochondria. The molecular weights of the most active preparations fall between 2000 and 2600. PGBx is characterized by a single-line electron spin resonan...

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

authors： Polis BD,Polis E,Kwong S

更新日期：1979-04-01 00:00:00

abstract：:Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tool...

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

authors： Bruni GN,Weekley RA,Dodd BJT,Kralj JM

更新日期：2017-08-29 00:00:00

abstract：:The bacterial actin homolog, MreB, forms helical cables within the cell that are required for maintenance of a rod shape. These helical structures are thought to be involved in the spatial organization of cell wall (peptidoglycan) synthesizing complexes of penicillin-binding proteins (PBPs). Here, we examined the role...

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

authors： Divakaruni AV,Loo RR,Xie Y,Loo JA,Gober JW

更新日期：2005-12-20 00:00:00

abstract：:Neural crest stem cells can be isolated from differentiated cultures of human pluripotent stem cells, but the process is inefficient and requires cell sorting to obtain a highly enriched population. No specific method for directed differentiation of human pluripotent cells toward neural crest stem cells has yet been r...

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

authors： Menendez L,Yatskievych TA,Antin PB,Dalton S

更新日期：2011-11-29 00:00:00

abstract：:A segment of DNA containing cya, the gene for adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1], has been isolated from Salmonella typhimurium. The phage lambda gt4 was used as a cloning vector and adenylate cyclase-positive hybrid phages were isolated that complemented adenylate cyclase-negative bac...

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

authors： Wang JY,Clegg DO,Koshland DE Jr

更新日期：1981-08-01 00:00:00

abstract：:The effects of three anti-inflammatory drugs, which interfere with arachidonic acid transformation by three different enzymes, have been compared by using a simple model of tissue damage and foreign body rejection. In groups of control rats, subcutaneously implanted polyester sponges were rejected after a mean of 12 d...

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

authors： Higgs GA,Mugridge KG,Moncada S,Vane JR

更新日期：1984-05-01 00:00:00

abstract：:Two objects with homologous landmarks are said to be of the same shape if the configuration of landmarks of one object can be exactly matched with that of the other by translation, rotation/reflection, and scaling. In an earlier paper, the authors proposed statistical analysis of shape by considering logarithmic diffe...

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

authors： Rao CR,Suryawanshi S

更新日期：1998-04-14 00:00:00

abstract：:The rRNA intervening sequence of Tetrahymena is a catalytic RNA molecule, or "ribozyme." A tertiary-structure model of the active site of this ribozyme has been constructed based on comparative sequence analysis of related group I intervening sequences, data on the accessibility of each nucleotide to chemical and enzy...

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

authors： Kim SH,Cech TR

更新日期：1987-12-01 00:00:00

abstract：:In photosynthesis, light is captured by antenna proteins. These proteins transfer the excitation energy with almost 100% quantum efficiency to the reaction centers, where charge separation takes place. The time scale and pathways of this transfer are controlled by the protein scaffold, which holds the pigments at opti...

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

authors： Müh F,Madjet Mel-A,Adolphs J,Abdurahman A,Rabenstein B,Ishikita H,Knapp EW,Renger T

更新日期：2007-10-23 00:00:00

abstract：:We introduce a paradigm-"hydricity"-that involves the coproduction of hydrogen and electricity from solar thermal energy and their judicious use to enable a sustainable economy. We identify and implement synergistic integrations while improving each of the two individual processes. When the proposed integrated process...

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

authors： Gençer E,Mallapragada DS,Maréchal F,Tawarmalani M,Agrawal R

更新日期：2015-12-29 00:00:00

abstract：:When rat pancreatic polynucleosomes were poly(ADP-ribosyl)ated with purified calf thymus poly(ADP-ribose) polymerase and examined by electron microscopy, a relaxation of their native zigzag structure was observed. At high ionic strengths control nucleosomes condensed into 250-A-thick fibers, but poly(ADP-ribosyl)ated ...

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

authors： Poirier GG,de Murcia G,Jongstra-Bilen J,Niedergang C,Mandel P

更新日期：1982-06-01 00:00:00

abstract：:Analogy-the ability to find and apply deep structural patterns across domains-has been fundamental to human innovation in science and technology. Today there is a growing opportunity to accelerate innovation by moving analogy out of a single person's mind and distributing it across many information processors, both hu...

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

authors： Kittur A,Yu L,Hope T,Chan J,Lifshitz-Assaf H,Gilon K,Ng F,Kraut RE,Shahaf D

更新日期：2019-02-05 00:00:00

abstract：:The neurotrophin (NT) brain-derived neurotrophic factor (BDNF) plays an essential role in the formation of long-term potentiation (LTP). Here, we address whether this modulation by BDNF requires its continuous presence, or whether a local increase in BDNF is necessary during a specific time period of LTP initiation. U...

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

authors： Gärtner A,Staiger V

更新日期：2002-04-30 00:00:00

abstract：:Titania, which exhibits superwetting under light illumination, has been widely used as an ideal material for environmental solution such as self-cleaning, water-air purification, and antifogging. There have been various studies to understand such superhydrophilic conversion. The origin of superwetting has not been cla...

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

authors： Lee K,Kim Q,An S,An J,Kim J,Kim B,Jhe W

更新日期：2014-04-22 00:00:00

abstract：:Erythropoietin (EPO) produced by the kidney and the liver (in fetuses) stimulates erythropoiesis. In the central nervous system, neurons express EPO receptor (EPOR) and astrocytes produce EPO. EPO has been shown to protect primary cultured neurons from N-methyl-D-aspartate (NMDA) receptor-mediated glutamate toxicity. ...

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

authors： Sakanaka M,Wen TC,Matsuda S,Masuda S,Morishita E,Nagao M,Sasaki R

更新日期：1998-04-14 00:00:00

abstract：:We have developed a cell-free system to study bacteriophage lambda DNA replication. Maximal DNA synthesis in vitro requires the four deoxynucleoside triphosphates, ATP, and exogenous lambda DNA. DNA synthesis requires the products of the phage O and P genes but is not inhibited by lambda repressor. The kinetics of syn...

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

authors： Shizuya H,Richardson CC

更新日期：1974-05-01 00:00:00

abstract：:Infection of mice with sporozoites of Plasmodium berghei or Plasmodium yoelii has been used extensively to evaluate liver-stage protection by candidate preerythrocytic malaria vaccines. Unfortunately, repeated success of such vaccines in mice has not translated readily to effective malaria vaccines in humans. Thus, mi...

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

authors： Schmidt NW,Podyminogin RL,Butler NS,Badovinac VP,Tucker BJ,Bahjat KS,Lauer P,Reyes-Sandoval A,Hutchings CL,Moore AC,Gilbert SC,Hill AV,Bartholomay LC,Harty JT

更新日期：2008-09-16 00:00:00

abstract：:The oxygen isotope record of the last million years, as provided by a deep sea core sediment, is analyzed by a method recently developed in the theory of dynamical systems. The analysis suggests that climatic variability is the manifestation of a chaotic dynamics described by an attractor of fractal dimensionality. A ...

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

authors： Nicolis C,Nicolis G

更新日期：1986-02-01 00:00:00

abstract：:Outside of the tropics, environmental conditions fluctuate in a generally predictable manner across the year. Many small mammals have evolved mechanisms, such as seasonal breeding and annual adjustments in physiology, morphology, and behavior, that promote winter survival when food is scarce and thermoregulation is ch...

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

authors： Weil ZM,Norman GJ,DeVries AC,Berntson GG,Nelson RJ

更新日期：2009-03-17 00:00:00