Additive effects of simulated climate changes, elevated CO2, and nitrogen deposition on grassland diversity.

abstract：:The polyamines, putrescine, spermidine, and spermine, are essential polycations, intimately involved in the regulation of cellular proliferation. Although polyamines exert dynamic effects on the conformation of nucleic acids and macromolecular synthesis in vitro, their specific functions in vivo are poorly understood....

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

authors： Mandal S,Mandal A,Johansson HE,Orjalo AV,Park MH

更新日期：2013-02-05 00:00:00

abstract：:Despite the widespread occurrence of spliceosomal introns in the genomes of higher eukaryotes, their origin remains controversial. One model proposes that the duplication of small genomic portions could have provided the boundaries for new introns. If this mechanism has occurred recently, the 5' and 3' boundaries of e...

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

authors： Zhuo D,Madden R,Elela SA,Chabot B

更新日期：2007-01-16 00:00:00

abstract：:Under steady-state conditions, the immune system is poised to sense and respond to the microbiota. As such, immunity to the microbiota, including T cell responses, is expected to precede any inflammatory trigger. How this pool of preformed microbiota-specific T cells contributes to tissue pathologies remains unclear. ...

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

authors： Hurabielle C,Link VM,Bouladoux N,Han SJ,Merrill ED,Lightfoot YL,Seto N,Bleck CKE,Smelkinson M,Harrison OJ,Linehan JL,Tamoutounour S,Lionakis MS,Kaplan MJ,Nakajima S,Belkaid Y

更新日期：2020-07-14 00:00:00

abstract：:A convenient technique for the partial purification of large quantities of functional, poly(adenylic acid)-rich mRNA is described. The method depends upon annealing poly(adenylic acid)-rich mRNA to oligothymidylic acid-cellulose columns and its elution with buffers of low ionic strength. Biologically active rabbit glo...

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

authors： Aviv H,Leder P

更新日期：1972-06-01 00:00:00

abstract：:E12 and E47 are two non-tissue-specific helix-loop-helix (HLH) transcription factors encoded by the E2A gene. Previous studies suggested that they are involved in regulation of differentiation in many tissue types including muscle, blood, and nerve through direct heterodimer interactions with tissue-specific HLH prote...

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

authors： Zhuang Y,Kim CG,Bartelmez S,Cheng P,Groudine M,Weintraub H

更新日期：1992-12-15 00:00:00

abstract：:The mechanism by which cells recognize and complete replicated regions at their precise doubling point must be remarkably efficient, occurring thousands of times per cell division along the chromosomes of humans. However, this process remains poorly understood. Here we show that, in Escherichia coli, the completion of...

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

authors： Wendel BM,Courcelle CT,Courcelle J

更新日期：2014-11-18 00:00:00

abstract：:Uropathogenic Escherichia coli invade bladder epithelial cells (BECs) by direct entry into specialized cAMP regulated exocytic compartments. Remarkably, a significant number of these intracellular bacteria are subsequently expelled in a nonlytic and piecemeal fashion by infected BECs. Here, we report that expulsion of...

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

authors： Song J,Bishop BL,Li G,Grady R,Stapleton A,Abraham SN

更新日期：2009-09-01 00:00:00

abstract：:The effects of the thymic polypeptide thymopoietin (Tpo) on the properties of the nicotinic acetylcholine receptor (AcChoR) were investigated by patch clamp techniques on mouse C2 myotubes and by biochemical assays on AcChoR-rich membrane fragments purified from the Torpedo marmorata electric organ. At high concentrat...

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

authors： Revah F,Mulle C,Pinset C,Audhya T,Goldstein G,Changeux JP

更新日期：1987-05-01 00:00:00

abstract：:Island biogeography theory posits that species richness increases with island size and decreases with isolation. This logic underpins much conservation policy and regulation, with preference given to conserving large, highly connected areas, and relative ambivalence shown toward protecting small, isolated habitat patc...

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

authors： Wintle BA,Kujala H,Whitehead A,Cameron A,Veloz S,Kukkala A,Moilanen A,Gordon A,Lentini PE,Cadenhead NCR,Bekessy SA

更新日期：2019-01-15 00:00:00

abstract：:Arylhydrazinopyrimidines inhibit DNA synthesis in Bacillus subtilis by promoting formation of a specific, long-lived ternary complex with DNA polymerase III and the template-primer DNA. DNA polymerase III contains an associated, single-strand-selective exonuclease which generates 5'-mononucleotides. Drug inhibition of...

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

authors： Low RL,Rashbaum SA,Cozzarelli NR

更新日期：1974-08-01 00:00:00

abstract：:Incubation of physiological concentrations of 125I-labeled insulin with liver membranes in the presence of anti-insulin IgG results in a 7- to 15-fold increase in the specific binding of the hormone. The low-affinity/high-capacity binding sites are replaced by an apparently homogeneous class of high-affinity sites, an...

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

authors： Shechter Y,Chang KJ,Jacobs S,Cuatrecasas P

更新日期：1979-06-01 00:00:00

abstract：:Optical waveguides simultaneously transport light at different colors, forming the basis of fiber-optic telecommunication networks that shuttle data in dozens of spectrally separated channels. Here, we reimagine this wavelength division multiplexing (WDM) paradigm in a novel context--the differentiated detection and i...

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

authors： Ozcelik D,Parks JW,Wall TA,Stott MA,Cai H,Parks JW,Hawkins AR,Schmidt H

更新日期：2015-10-20 00:00:00

abstract：:Rising sea levels and increased storminess are expected to accelerate the erosion of soft-cliff coastlines, threatening coastal infrastructure and livelihoods. To develop predictive models of future coastal change we need fundamentally to know how rapidly coasts have been eroding in the past, and to understand the dri...

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

authors： Hurst MD,Rood DH,Ellis MA,Anderson RS,Dornbusch U

更新日期：2016-11-22 00:00:00

abstract：:The size and metabolic rate of cells affect processes from the molecular to the organismal level. We present a quantitative, theoretical framework for studying relationships among cell volume, cellular metabolic rate, body size, and whole-organism metabolic rate that helps reveal the feedback between these levels of o...

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

authors： Savage VM,Allen AP,Brown JH,Gillooly JF,Herman AB,Woodruff WH,West GB

更新日期：2007-03-13 00:00:00

abstract：:In mammalian females, most genes on one X chromosome are transcriptionally silenced as a result of X chromosome inactivation. Whereas it is well established that some X-linked genes "escape" X inactivation and are expressed from both active (Xa) and inactive (Xi) X chromosomes, most models for the chromosomal control ...

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

authors： Carrel L,Willard HF

更新日期：1999-06-22 00:00:00

abstract：:Phage phi 29 DNA cannot be phosphorylated with polynucleotide kinase and [gamma-32P]ATP because of the presence of a viral protein covalently linked to the 5' termini. The 5' ends can, however, be made susceptible to phosphorylation by treatment with alkali and alkaline phosphatase. Restriction fragments Hpa II C and ...

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

authors： Escarmís C,Salas M

更新日期：1981-03-01 00:00:00

abstract：:Antigen-induced activation of T cells can be specifically inhibited by antigen analogs that have been termed T-cell receptor peptide antagonists. These antagonists appear to act by inducing the formation of nonstimulatory or partially stimulatory complexes between T-cell receptors and the major histocompatibility comp...

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

authors： Page DM,Alexander J,Snoke K,Appella E,Sette A,Hedrick SM,Grey HM

更新日期：1994-04-26 00:00:00

abstract：:Sublethal insults can induce tolerance to subsequent stressors in neurons. As cell death activators such as ROS generation and decreased ATP can initiate tolerance, we tested whether other cellular elements normally associated with neuronal injury could add to this process. In an in vivo model of ischemic tolerance, w...

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

authors： McLaughlin B,Hartnett KA,Erhardt JA,Legos JJ,White RF,Barone FC,Aizenman E

更新日期：2003-01-21 00:00:00

abstract：:We present an automated laser tracking and optogenetic manipulation system (ALTOMS) for studying social memory in fruit flies (Drosophila melanogaster). ALTOMS comprises an intelligent central control module for high-speed fly behavior analysis and feedback laser scanning (∼40 frames per second) for targeting two lase...

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

authors： Wu MC,Chu LA,Hsiao PY,Lin YY,Chi CC,Liu TH,Fu CC,Chiang AS

更新日期：2014-04-08 00:00:00

abstract：:Prior studies have identified a subset of dendritic cells in human blood, as well as their stimulatory function for T-cell-mediated immune responses. However research has been limited by difficulties in isolation, since dendritic cells make up only 0.1-1% of blood mononuclear cells. We present a protocol that reliably...

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

authors： Freudenthal PS,Steinman RM

更新日期：1990-10-01 00:00:00

abstract：:The major auxin-binding protein in maize membranes is thought to function as a physiological receptor. From earlier information, including the use of site-directed irreversible inhibitors, several of the amino acids likely to form part of the active auxin-binding site were provisionally assigned. Inspection of the ami...

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

authors： Venis MA,Napier RM,Barbier-Brygoo H,Maurel C,Perrot-Rechenmann C,Guern J

更新日期：1992-08-01 00:00:00

abstract：:The nucleus accumbens (NAc) serves as a key neural substrate that controls acute and adaptive behavioral responses to cocaine administration. In this circuit, inputs from the NAc are transmitted through two parallel pathways, named the direct and indirect pathways, and converge at the substantia nigra pars reticulata ...

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

authors： Kimura K,Hikida T,Yawata S,Yamaguchi T,Nakanishi S

更新日期：2011-06-14 00:00:00

abstract：:Current drug discovery efforts focus on identifying lead compounds acting on a molecular target associated with an established pathological state. Concerted molecular changes that occur in specific cell types during disease progression have generally not been identified. Here, we used constellation pharmacology to inv...

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

authors： Raghuraman S,Xie JY,Giacobassi MJ,Tun JO,Chase K,Lu D,Teichert RW,Porreca F,Olivera BM

更新日期：2020-10-20 00:00:00

abstract：:Defining bacterial species remains a challenging problem even for the model bacterium Escherichia coli and has major practical consequences for reliable diagnosis of infectious disease agents and regulations for transport and possession of organisms of economic importance. E. coli traditionally is thought to live with...

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

authors： Luo C,Walk ST,Gordon DM,Feldgarden M,Tiedje JM,Konstantinidis KT

更新日期：2011-04-26 00:00:00

abstract：:Urinary acidification by the turtle bladder is due to a H+-ATPase that is located in the luminal membrane. The rate of H+ transport is stimulated by an increase in the ambient CO2. Using the fluorescent dye acridine orange, we showed that the mitochondria-rich cell of this equilibrium contains vesicles whose internal ...

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

authors： Gluck S,Cannon C,Al-Awqati Q

更新日期：1982-07-01 00:00:00

abstract：:X-ray diffraction studies have produced a low resolution image and also located the iron atoms of a monomeric hemerythrin from muscles of a sipunculan worm. These results reveal the course of the polypeptide chain and some details of the active center. ...

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

authors： Hendrickson WA,Klippenstein GL,Ward KB

更新日期：1975-06-01 00:00:00

abstract：:Synthesis of normal human hemoglobin A, alpha 2 beta 2, is based upon balanced expression of genes in the alpha-globin gene cluster on chromosome 16 and the beta-globin gene cluster on chromosome 11. Full levels of erythroid-specific activation of the beta-globin cluster depend on sequences located at a considerable d...

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

authors： Liebhaber SA,Griese EU,Weiss I,Cash FE,Ayyub H,Higgs DR,Horst J

更新日期：1990-12-01 00:00:00

abstract：:Light activates rod outer segment (ROS) phosphodiesterase (PDEase), as shown by previous biochemical and physiological studies. We have further investigated the role of PDEase in this system by injecting trypsin-activated PDEase, purified from bovine ROS, into single ROS of the isolated retina of the toad Bufo marinus...

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

authors： Shimoda Y,Hurley JB,Miller WH

更新日期：1984-01-01 00:00:00

abstract：:Although it has been known for decades that the tight junctions of fluid-transporting epithelia are leaky to ions, it has not been possible to determine directly whether significant transjunctional water movement also occurs. An optical microscopic technique was developed for the direct visualization of the flow veloc...

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

authors： Kovbasnjuk O,Leader JP,Weinstein AM,Spring KR

更新日期：1998-05-26 00:00:00

abstract：:A genomic clone coding for the alpha subunit of the mouse complement receptor type 3 and the cellular adhesion molecule Mac-1 has been isolated directly from a genomic library using synthetic oligonucleotide probes based on the amino-terminal amino acid sequence of the protein. The identity of the clone has been estab...

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

authors： Sastre L,Roman JM,Teplow DB,Dreyer WJ,Gee CE,Larson RS,Roberts TM,Springer TA

更新日期：1986-08-01 00:00:00