ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Kinetics
  • American Association for the Advancement of Science (AAAS)  (191)
  • American Institute of Physics
  • 2010-2014  (55)
  • 1980-1984  (136)
Sammlung
Verlag/Herausgeber
Erscheinungszeitraum
Jahr
  • 1
    Publikationsdatum: 2014-05-09
    Beschreibung: The regenerative power of tissues and organs in biology has no analog in synthetic materials. Although self-healing of microscopic defects has been demonstrated, the regrowth of material lost through catastrophic damage requires a regenerative-like approach. We demonstrate a vascular synthetic system that restores mechanical performance in response to large-scale damage. Gap-filling scaffolds are created through a two-stage polymer chemistry that initially forms a shape-conforming dynamic gel but later polymerizes to a solid structural polymer with robust mechanical properties. Through the control of reaction kinetics and vascular delivery rate, we filled impacted regions that exceed 35 mm in diameter within 20 min and restored mechanical function within 3 hours. After restoration of impact damage, 62% of the total absorbed energy was recovered in comparison with that in initial impact tests.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉White, S R -- Moore, J S -- Sottos, N R -- Krull, B P -- Santa Cruz, W A -- Gergely, R C R -- New York, N.Y. -- Science. 2014 May 9;344(6184):620-3. doi: 10.1126/science.1251135.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24812399" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Gels/chemistry ; Kinetics ; Mechanical Processes ; Models, Chemical ; *Polymerization ; Polymers/*chemistry ; *Regeneration
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Publikationsdatum: 2014-08-16
    Beschreibung: The assembly of artificial cells capable of executing synthetic DNA programs has been an important goal for basic research and biotechnology. We assembled two-dimensional DNA compartments fabricated in silicon as artificial cells capable of metabolism, programmable protein synthesis, and communication. Metabolism is maintained by continuous diffusion of nutrients and products through a thin capillary, connecting protein synthesis in the DNA compartment with the environment. We programmed protein expression cycles, autoregulated protein levels, and a signaling expression gradient, equivalent to a morphogen, in an array of interconnected compartments at the scale of an embryo. Gene expression in the DNA compartment reveals a rich, dynamic system that is controlled by geometry, offering a means for studying biological networks outside a living cell.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karzbrun, Eyal -- Tayar, Alexandra M -- Noireaux, Vincent -- Bar-Ziv, Roy H -- New York, N.Y. -- Science. 2014 Aug 15;345(6198):829-32. doi: 10.1126/science.1255550.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel. ; Department of Physics, University of Minnesota, Minneapolis, MN 55455, USA. ; Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel. roy.bar-ziv@weizmann.ac.il.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25124443" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Artificial Cells/*metabolism/ultrastructure ; *DNA/genetics/metabolism ; Diffusion ; *Gene Expression ; Gene Expression Regulation ; Gene Regulatory Networks ; Green Fluorescent Proteins/genetics/metabolism ; Kinetics ; Microfluidic Analytical Techniques ; Oligonucleotide Array Sequence Analysis ; Proteins/*metabolism ; Silicon ; Software ; Synthetic Biology/methods ; Templates, Genetic ; Transcription, Genetic
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Publikationsdatum: 2014-02-08
    Beschreibung: Although the effects of kinetics on crystal growth are well understood, the role of substrate curvature is not yet established. We studied rigid, two-dimensional colloidal crystals growing on spherical droplets to understand how the elastic stress induced by Gaussian curvature affects the growth pathway. In contrast to crystals grown on flat surfaces or compliant crystals on droplets, these crystals formed branched, ribbon-like domains with large voids and no topological defects. We show that this morphology minimizes the curvature-induced elastic energy. Our results illustrate the effects of curvature on the ubiquitous process of crystallization, with practical implications for nanoscale disorder-order transitions on curved manifolds, including the assembly of viral capsids, phase separation on vesicles, and crystallization of tetrahedra in three dimensions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meng, Guangnan -- Paulose, Jayson -- Nelson, David R -- Manoharan, Vinothan N -- New York, N.Y. -- Science. 2014 Feb 7;343(6171):634-7. doi: 10.1126/science.1244827.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Harvard University, Cambridge, MA 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24503849" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Capsid/chemistry ; Colloids/*chemistry ; Crystallization/*statistics & numerical data ; *Elasticity ; Kinetics ; Normal Distribution ; *Stress, Mechanical
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Publikationsdatum: 2014-07-06
    Beschreibung: Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras-guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4255705/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4255705/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Iversen, Lars -- Tu, Hsiung-Lin -- Lin, Wan-Chen -- Christensen, Sune M -- Abel, Steven M -- Iwig, Jeff -- Wu, Hung-Jen -- Gureasko, Jodi -- Rhodes, Christopher -- Petit, Rebecca S -- Hansen, Scott D -- Thill, Peter -- Yu, Cheng-Han -- Stamou, Dimitrios -- Chakraborty, Arup K -- Kuriyan, John -- Groves, Jay T -- P01 AI091580/AI/NIAID NIH HHS/ -- R01 AI104789/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2014 Jul 4;345(6192):50-4. doi: 10.1126/science.1250373.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA. ; Department of Chemical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA. ; Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA. ; Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720, USA. ; Department of Chemistry, MIT, Cambridge, MA 02139, USA. ; Mechanobiology Institute, National University of Singapore, Singapore. ; Department of Chemistry and Nano-Science Center, University of Copenhagen, Copenhagen, Denmark. ; Department of Chemical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA. Department of Chemistry, MIT, Cambridge, MA 02139, USA. Department of Biological Engineering, MIT, Cambridge, MA 02139, USA. Ragon Institute of Massachusetts General Hospital, MIT, and Harvard, Cambridge, MA 02139, USA. Department of Physics, MIT, Cambridge, MA 02139, USA. Institute for Medical Engineering and Science, MIT, Cambridge, MA 02139, USA. ; Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA. Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA. Physical Biosciences and Materials Sciences Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ; Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA. Mechanobiology Institute, National University of Singapore, Singapore. Physical Biosciences and Materials Sciences Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Berkeley Education Alliance for Research in Singapore, 1 Create Way, CREATE tower level 11, University Town, Singapore 138602. jtgroves@lbl.gov.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24994643" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Allosteric Regulation ; Catalytic Domain ; Crystallography, X-Ray ; Enzyme Activation ; Humans ; Kinetics ; Nucleotides/chemistry ; *Protein Interaction Domains and Motifs ; Proto-Oncogene Proteins p21(ras)/*agonists ; Son of Sevenless Protein, Drosophila/*chemistry/genetics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Publikationsdatum: 2014-12-20
    Beschreibung: Variability in gene expression among genetically identical cells has emerged as a central preoccupation in the study of gene regulation; however, a divide exists between the predictions of molecular models of prokaryotic transcriptional regulation and genome-wide experimental studies suggesting that this variability is indifferent to the underlying regulatory architecture. We constructed a set of promoters in Escherichia coli in which promoter strength, transcription factor binding strength, and transcription factor copy numbers are systematically varied, and used messenger RNA (mRNA) fluorescence in situ hybridization to observe how these changes affected variability in gene expression. Our parameter-free models predicted the observed variability; hence, the molecular details of transcription dictate variability in mRNA expression, and transcriptional noise is specifically tunable and thus represents an evolutionarily accessible phenotypic parameter.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4388425/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4388425/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jones, Daniel L -- Brewster, Robert C -- Phillips, Rob -- 1 U54 CA143869/CA/NCI NIH HHS/ -- DP1 OD000217/OD/NIH HHS/ -- R01 GM085286/GM/NIGMS NIH HHS/ -- U54 CA143869/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2014 Dec 19;346(6216):1533-6. doi: 10.1126/science.1255301. Epub 2014 Dec 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA. ; Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA. Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA. ; Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA. Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA. phillips@pboc.caltech.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25525251" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Cells/*metabolism ; DNA-Directed RNA Polymerases/metabolism ; Escherichia coli/genetics ; Gene Dosage ; *Gene Expression Regulation ; *Genetic Variation ; In Situ Hybridization ; Kinetics ; Lac Repressors/genetics/metabolism ; Models, Genetic ; *Promoter Regions, Genetic ; Protein Binding ; RNA, Messenger/genetics ; Transcription, Genetic
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2013-12-07
    Beschreibung: In individual cells, transcription is a random process obeying single-molecule kinetics. Often, it occurs in a bursty, intermittent manner. The frequency and size of these bursts affect the magnitude of temporal fluctuations in messenger RNA and protein content within a cell, creating variation or "noise" in gene expression. It is still unclear to what degree transcriptional kinetics are specific to each gene and determined by its promoter sequence. Alternative scenarios have been proposed, in which the kinetics of transcription are governed by cellular constraints and follow universal rules across the genome. Evidence from genome-wide noise studies and from systematic perturbations of promoter sequences suggest that both scenarios-namely gene-specific versus genome-wide regulation of transcription kinetics-may be present to different degrees in bacteria, yeast, and animal cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045091/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045091/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanchez, Alvaro -- Golding, Ido -- R01 GM082837/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2013 Dec 6;342(6163):1188-93. doi: 10.1126/science.1242975.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Rowland Institute at Harvard, Harvard University, Cambridge, MA 02142, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24311680" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Escherichia coli/genetics/metabolism ; Eukaryota/genetics/metabolism ; *Gene Expression Regulation ; Genome ; Kinetics ; Models, Genetic ; Promoter Regions, Genetic ; RNA, Messenger/genetics/metabolism ; Single-Cell Analysis ; Stochastic Processes ; *Transcription, Genetic ; Yeasts/genetics/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Publikationsdatum: 2013-03-09
    Beschreibung: RNA chaperones are ubiquitous, heterogeneous proteins essential for RNA structural biogenesis and function. We investigated the mechanism of chaperone-mediated RNA folding by following the time-resolved dimerization of the packaging domain of a retroviral RNA at nucleotide resolution. In the absence of the nucleocapsid (NC) chaperone, dimerization proceeded through multiple, slow-folding intermediates. In the presence of NC, dimerization occurred rapidly through a single structural intermediate. The RNA binding domain of heterogeneous nuclear ribonucleoprotein A1 protein, a structurally unrelated chaperone, also accelerated dimerization. Both chaperones interacted primarily with guanosine residues. Replacing guanosine with more weakly pairing inosine yielded an RNA that folded rapidly without a facilitating chaperone. These results show that RNA chaperones can simplify RNA folding landscapes by weakening intramolecular interactions involving guanosine and explain many RNA chaperone activities.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338410/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338410/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Grohman, Jacob K -- Gorelick, Robert J -- Lickwar, Colin R -- Lieb, Jason D -- Bower, Brian D -- Znosko, Brent M -- Weeks, Kevin M -- GM031819/GM/NIGMS NIH HHS/ -- GM064803/GM/NIGMS NIH HHS/ -- GM072518/GM/NIGMS NIH HHS/ -- HHSN261200800001E/PHS HHS/ -- R01 GM031819/GM/NIGMS NIH HHS/ -- R01 GM064803/GM/NIGMS NIH HHS/ -- T32 GM007092/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2013 Apr 12;340(6129):190-5. doi: 10.1126/science.1230715. Epub 2013 Mar 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23470731" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Base Sequence ; Dimerization ; Guanosine/chemistry/*metabolism ; Heterogeneous-Nuclear Ribonucleoprotein Group A-B/chemistry/metabolism ; Inosine/chemistry/metabolism ; Kinetics ; Models, Molecular ; Molecular Chaperones/chemistry/*metabolism ; Moloney murine leukemia virus/genetics/*metabolism ; Nucleic Acid Conformation ; Nucleocapsid Proteins/chemistry/*metabolism ; Protein Binding ; RNA, Viral/*chemistry/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2013-12-21
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xie, X Sunney -- New York, N.Y. -- Science. 2013 Dec 20;342(6165):1457-9. doi: 10.1126/science.1248859.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA, and Biodynamic Optical Imaging Center (BIOPIC), Peking University, Beijing 100871, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24357307" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Catalysis ; Enzymes/*chemistry ; Fluorescence ; Kinetics ; Molecular Imaging ; Optical Imaging
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Publikationsdatum: 2013-10-05
    Beschreibung: The chromatin immunoprecipitation (ChIP) assay is widely used to capture interactions between chromatin and regulatory proteins, but it is unknown how stable most native interactions are. Although live-cell imaging suggests short-lived interactions at tandem gene arrays, current methods cannot measure rapid binding dynamics at single-copy genes. We show, by using a modified ChIP assay with subsecond temporal resolution, that the time dependence of formaldehyde cross-linking can be used to extract in vivo on and off rates for site-specific chromatin interactions varying over a ~100-fold dynamic range. By using the method, we show that a regulatory process can shift weakly bound TATA-binding protein to stable promoter interactions, thereby facilitating transcription complex formation. This assay provides an approach for systematic, quantitative analyses of chromatin binding dynamics in vivo.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3997053/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3997053/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Poorey, Kunal -- Viswanathan, Ramya -- Carver, Melissa N -- Karpova, Tatiana S -- Cirimotich, Shana M -- McNally, James G -- Bekiranov, Stefan -- Auble, David T -- GM55763/GM/NIGMS NIH HHS/ -- R01 GM055763/GM/NIGMS NIH HHS/ -- Intramural NIH HHS/ -- New York, N.Y. -- Science. 2013 Oct 18;342(6156):369-72. doi: 10.1126/science.1242369. Epub 2013 Oct 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24091704" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphatases/chemistry/metabolism ; Chromatin/chemistry/*metabolism ; Chromatin Immunoprecipitation/*methods ; Cross-Linking Reagents/chemistry ; DNA-Binding Proteins/chemistry/metabolism ; Formaldehyde/chemistry ; Gene Dosage ; *Gene Expression Regulation ; Kinetics ; Promoter Regions, Genetic ; Saccharomyces cerevisiae Proteins/chemistry/metabolism ; TATA-Binding Protein Associated Factors/chemistry/metabolism ; TATA-Box Binding Protein/chemistry/*metabolism ; Transcription Factors/chemistry/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Publikationsdatum: 2013-02-09
    Beschreibung: Piperidines are prevalent in natural products and pharmaceutical agents and are important synthetic targets for drug discovery and development. We report on a methodology that provides highly substituted piperidine derivatives with regiochemistry selectively tunable by varying the strength of acid used in the reaction. Readily available starting materials are first converted to dihydropyridines via a cascade reaction initiated by rhodium-catalyzed carbon-hydrogen bond activation. Subsequent divergent regio- and diastereoselective protonation of the dihydropyridines under either kinetic or thermodynamic control provides two distinct iminium ion intermediates that then undergo highly diastereoselective nucleophilic additions. X-ray structural characterization of both the kinetically and thermodynamically favored iminium ions along with density functional theory calculations provide a theoretical underpinning for the high selectivities achieved for the reaction sequences.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809088/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809088/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Duttwyler, Simon -- Chen, Shuming -- Takase, Michael K -- Wiberg, Kenneth B -- Bergman, Robert G -- Ellman, Jonathan A -- GM069559/GM/NIGMS NIH HHS/ -- R01 GM069559/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2013 Feb 8;339(6120):678-82. doi: 10.1126/science.1230704.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Yale University, New Haven, CT 06520, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23393259" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Acids ; Catalysis ; Crystallography, X-Ray ; Dihydropyridines/chemistry ; Heterocyclic Compounds/*chemical synthesis/chemistry ; Hydrogen Bonding ; Kinetics ; Molecular Conformation ; Molecular Structure ; Nitrogen/*chemistry ; Piperidines/*chemical synthesis/*chemistry ; *Protons ; Rhodium ; Stereoisomerism ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 11
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2012-11-10
    Beschreibung: Despite more than 30 years of work on the Wnt signaling pathway, the basic mechanism of how the extracellular Wnt signal increases the intracellular concentration of beta-catenin is still contentious. Circumventing much of the detailed biochemistry, we used basic principles of chemical kinetics coupled with quantitative measurements to define the reactions on beta-catenin directly affected by the Wnt signal. We conclude that the core signal transduction mechanism is relatively simple, with only two regulated phosphorylation steps. Their partial inhibition gives rise to the full dynamics of the response and subsequently maintains a steady state in which the concentration of beta-catenin is increased.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hernandez, Ana R -- Klein, Allon M -- Kirschner, Marc W -- New York, N.Y. -- Science. 2012 Dec 7;338(6112):1337-40. doi: 10.1126/science.1228734. Epub 2012 Nov 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23138978" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Casein Kinase I/chemistry/metabolism ; Cell Line, Tumor ; Cysteine Proteinase Inhibitors/pharmacology ; Glycogen Synthase Kinase 3/metabolism ; HEK293 Cells ; Humans ; Kinetics ; Leupeptins/pharmacology ; Phosphorylation ; *Signal Transduction ; Wnt Proteins/*metabolism ; Wnt3A Protein/metabolism ; beta Catenin/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 12
    Publikationsdatum: 2012-03-01
    Beschreibung: The transition path is the tiny fraction of an equilibrium molecular trajectory when a transition occurs as the free-energy barrier between two states is crossed. It is a single-molecule property that contains all the mechanistic information on how a process occurs. As a step toward observing transition paths in protein folding, we determined the average transition-path time for a fast- and a slow-folding protein from a photon-by-photon analysis of fluorescence trajectories in single-molecule Forster resonance energy transfer experiments. Whereas the folding rate coefficients differ by a factor of 10,000, the transition-path times differ by a factor of less than 5, which shows that a fast- and a slow-folding protein take almost the same time to fold when folding actually happens. A very simple model based on energy landscape theory can explain this result.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878298/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878298/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chung, Hoi Sung -- McHale, Kevin -- Louis, John M -- Eaton, William A -- Z99 DK999999/Intramural NIH HHS/ -- New York, N.Y. -- Science. 2012 Feb 24;335(6071):981-4. doi: 10.1126/science.1215768.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD 20892-0520, USA. chunghoi@niddk.nih.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22363011" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amino Acid Sequence ; Bacterial Proteins/*chemistry ; Carrier Proteins/*chemistry ; Fluorescence Resonance Energy Transfer ; Kinetics ; Likelihood Functions ; Models, Molecular ; Molecular Sequence Data ; Photons ; Protein Conformation ; *Protein Folding ; Protein Interaction Domains and Motifs ; Protein Structure, Tertiary ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 13
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2012-10-23
    Beschreibung: Growing RNA chains fold cotranscriptionally as they are synthesized by RNA polymerase. Riboswitches, which regulate gene expression by adopting alternative RNA folds, are sensitive to cotranscriptional events. We developed an optical-trapping assay to follow the cotranscriptional folding of a nascent RNA and used it to monitor individual transcripts of the pbuE adenine riboswitch, visualizing distinct folding transitions. We report a particular folding signature for the riboswitch aptamer whose presence directs the gene-regulatory transcription outcome, and we measured the termination frequency as a function of adenine level and tension applied to the RNA. Our results demonstrate that the outcome is kinetically controlled. These experiments furnish a means to observe conformational switching in real time and enable the precise mapping of events during cotranscriptional folding.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3496414/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3496414/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Frieda, Kirsten L -- Block, Steven M -- R37 GM057035/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2012 Oct 19;338(6105):397-400. doi: 10.1126/science.1225722.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biophysics Program, Stanford University, Stanford, CA 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23087247" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenine/*chemistry/metabolism ; Bacillus subtilis/genetics ; Base Sequence ; Kinetics ; Molecular Sequence Data ; *Optical Tweezers ; *RNA Folding ; Riboswitch/*genetics ; *Transcription, Genetic
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 14
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2012-09-08
    Beschreibung: Spontaneous electrical signals in the retina's photoreceptors impose a limit on visual sensitivity. Their origin is attributed to a thermal, rather than photochemical, activation of the transduction cascade. Although the mechanism of such a process is under debate, the observation of a relationship between the maximum absorption wavelength (lambda(max)) and the thermal activation kinetic constant (k) of different visual pigments (the Barlow correlation) indicates that the thermal and photochemical activations are related. Here we show that a quantum chemical model of the bovine rod pigment provides a molecular-level understanding of the Barlow correlation. The transition state mediating thermal activation has the same electronic structure as the photoreceptor excited state, thus creating a direct link between lambda(max) and k. Such a link appears to be the manifestation of intrinsic chromophore features associated with the existence of a conical intersection between its ground and excited states.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gozem, Samer -- Schapiro, Igor -- Ferre, Nicolas -- Olivucci, Massimo -- New York, N.Y. -- Science. 2012 Sep 7;337(6099):1225-8. doi: 10.1126/science.1220461.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Bowling Green State University, Bowling Green, OH 43403, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22955833" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Cattle ; Isomerism ; Kinetics ; Models, Chemical ; Photochemical Processes ; Quantum Theory ; Retinal Rod Photoreceptor Cells/*chemistry/physiology ; Rhodopsin/*chemistry/*physiology ; Rod Opsins/chemistry/physiology ; Schiff Bases ; Temperature ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 15
    Publikationsdatum: 2012-06-23
    Beschreibung: Transcription factors (TFs) are proteins that regulate the expression of genes by binding sequence-specific sites on the chromosome. It has been proposed that to find these sites fast and accurately, TFs combine one-dimensional (1D) sliding on DNA with 3D diffusion in the cytoplasm. This facilitated diffusion mechanism has been demonstrated in vitro, but it has not been shown experimentally to be exploited in living cells. We have developed a single-molecule assay that allows us to investigate the sliding process in living bacteria. Here we show that the lac repressor slides 45 +/- 10 base pairs on chromosomal DNA and that sliding can be obstructed by other DNA-bound proteins near the operator. Furthermore, the repressor frequently (〉90%) slides over its natural lacO(1) operator several times before binding. This suggests a trade-off between rapid search on nonspecific sequences and fast binding at the specific sequence.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hammar, Petter -- Leroy, Prune -- Mahmutovic, Anel -- Marklund, Erik G -- Berg, Otto G -- Elf, Johan -- New York, N.Y. -- Science. 2012 Jun 22;336(6088):1595-8. doi: 10.1126/science.1221648.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22723426" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Binding Sites ; Chromosomes, Bacterial/metabolism ; DNA, Bacterial/*metabolism ; Escherichia coli/genetics/*metabolism ; Escherichia coli Proteins/*metabolism ; Facilitated Diffusion ; Kinetics ; *Lac Operon ; Lac Repressors/*metabolism ; *Operator Regions, Genetic ; Protein Binding ; Transcription Factors/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 16
    Publikationsdatum: 2012-04-14
    Beschreibung: microRNAs (miRNAs) regulate gene expression through translational repression and/or messenger RNA (mRNA) deadenylation and decay. Because translation, deadenylation, and decay are closely linked processes, it is important to establish their ordering and thus to define the molecular mechanism of silencing. We have investigated the kinetics of these events in miRNA-mediated gene silencing by using a Drosophila S2 cell-based controllable expression system and show that mRNAs with both natural and engineered 3' untranslated regions with miRNA target sites are first subject to translational inhibition, followed by effects on deadenylation and decay. We next used a natural translational elongation stall to show that miRNA-mediated silencing inhibits translation at an early step, potentially translation initiation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3971879/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3971879/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Djuranovic, Sergej -- Nahvi, Ali -- Green, Rachel -- R01 GM059425/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2012 Apr 13;336(6078):237-40. doi: 10.1126/science.1215691.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute (HHMI) and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22499947" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): 3' Untranslated Regions ; Animals ; Cell Line ; Drosophila Proteins/genetics ; Drosophila melanogaster/*genetics/metabolism ; *Gene Silencing ; Kinetics ; MicroRNAs/*genetics/metabolism ; Peptide Chain Elongation, Translational ; Peptide Chain Initiation, Translational ; *Protein Biosynthesis ; *RNA Stability ; RNA, Messenger/genetics/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 17
    Publikationsdatum: 2012-08-04
    Beschreibung: The synaptic adhesion molecules neurexin and neuroligin alter the development and function of synapses and are linked to autism in humans. Here, we found that Caenorhabditis elegans neurexin (NRX-1) and neuroligin (NLG-1) mediated a retrograde synaptic signal that inhibited neurotransmitter release at neuromuscular junctions. Retrograde signaling was induced in mutants lacking a muscle microRNA (miR-1) and was blocked in mutants lacking NLG-1 or NRX-1. Release was rapid and abbreviated when the retrograde signal was on, whereas release was slow and prolonged when retrograde signaling was blocked. The retrograde signal adjusted release kinetics by inhibiting exocytosis of synaptic vesicles (SVs) that are distal to the site of calcium entry. Inhibition of release was mediated by increased presynaptic levels of tomosyn, an inhibitor of SV fusion.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3791080/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3791080/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hu, Zhitao -- Hom, Sabrina -- Kudze, Tambudzai -- Tong, Xia-Jing -- Choi, Seungwon -- Aramuni, Gayane -- Zhang, Weiqi -- Kaplan, Joshua M -- NS32196/NS/NINDS NIH HHS/ -- R37 NS032196/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 2012 Aug 24;337(6097):980-4. doi: 10.1126/science.1224896. Epub 2012 Aug 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22859820" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Acetylcholine/metabolism ; Animals ; Caenorhabditis elegans/genetics/*physiology ; Caenorhabditis elegans Proteins/genetics/*metabolism ; Cell Adhesion Molecules, Neuronal/genetics/*metabolism ; Cholinergic Neurons/physiology ; Excitatory Postsynaptic Potentials ; Exocytosis ; Kinetics ; Mice ; MicroRNAs/genetics/metabolism ; Motor Neurons/physiology ; Mutation ; Neural Inhibition ; Neuromuscular Junction/*physiology ; Neurotransmitter Agents/metabolism ; *Synaptic Transmission ; Synaptic Vesicles/physiology ; Transcription Factors/genetics/metabolism ; Transfection
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 18
    Publikationsdatum: 2012-04-14
    Beschreibung: Biological systems involving short-range activators and long-range inhibitors can generate complex patterns. Reaction-diffusion models postulate that differences in signaling range are caused by differential diffusivity of inhibitor and activator. Other models suggest that differential clearance underlies different signaling ranges. To test these models, we measured the biophysical properties of the Nodal/Lefty activator/inhibitor system during zebrafish embryogenesis. Analysis of Nodal and Lefty gradients revealed that Nodals have a shorter range than Lefty proteins. Pulse-labeling analysis indicated that Nodals and Leftys have similar clearance kinetics, whereas fluorescence recovery assays revealed that Leftys have a higher effective diffusion coefficient than Nodals. These results indicate that differential diffusivity is the major determinant of the differences in Nodal/Lefty range and provide biophysical support for reaction-diffusion models of activator/inhibitor-mediated patterning.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3525670/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3525670/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Muller, Patrick -- Rogers, Katherine W -- Jordan, Ben M -- Lee, Joon S -- Robson, Drew -- Ramanathan, Sharad -- Schier, Alexander F -- 5R01GM56211/GM/NIGMS NIH HHS/ -- R01 GM056211/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2012 May 11;336(6082):721-4. doi: 10.1126/science.1221920. Epub 2012 Apr 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA. pmueller@fas.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22499809" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Blastula/*metabolism ; *Body Patterning ; Diffusion ; Embryonic Development ; Fluorescence Recovery After Photobleaching ; Half-Life ; Intracellular Signaling Peptides and Proteins/genetics/*metabolism ; Kinetics ; Left-Right Determination Factors/genetics/*metabolism ; Models, Biological ; Nodal Signaling Ligands/genetics/*metabolism ; Recombinant Fusion Proteins/metabolism ; Zebrafish/*embryology/metabolism ; Zebrafish Proteins/genetics/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 19
    Publikationsdatum: 2012-01-24
    Beschreibung: Tethering a single lysozyme molecule to a carbon nanotube field-effect transistor produced a stable, high-bandwidth transducer for protein motion. Electronic monitoring during 10-minute periods extended well beyond the limitations of fluorescence techniques to uncover dynamic disorder within a single molecule and establish lysozyme as a processive enzyme. On average, 100 chemical bonds are processively hydrolyzed, at 15-hertz rates, before lysozyme returns to its nonproductive, 330-hertz hinge motion. Statistical analysis differentiated single-step hinge closure from enzyme opening, which requires two steps. Seven independent time scales governing lysozyme's activity were observed. The pH dependence of lysozyme activity arises not from changes to its processive kinetics but rather from increasing time spent in either nonproductive rapid motions or an inactive, closed conformation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3914775/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3914775/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Choi, Yongki -- Moody, Issa S -- Sims, Patrick C -- Hunt, Steven R -- Corso, Brad L -- Perez, Israel -- Weiss, Gregory A -- Collins, Philip G -- R01 CA133592/CA/NCI NIH HHS/ -- R01 CA133592-01/CA/NCI NIH HHS/ -- T32 CA009054/CA/NCI NIH HHS/ -- T32CA009054/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2012 Jan 20;335(6066):319-24. doi: 10.1126/science.1214824.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Surface and Interface Science, University of California Irvine, Irvine, CA 92697-2375, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22267809" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Bacteriophage T4/enzymology ; Biocatalysis ; Electric Conductivity ; Fluorescence Resonance Energy Transfer ; Hydrogen-Ion Concentration ; Kinetics ; Microscopy, Atomic Force ; Muramidase/*chemistry/*metabolism ; Nanotubes, Carbon ; Peptidoglycan/metabolism ; Protein Conformation ; Pyrenes ; Static Electricity ; Thermodynamics ; Transistors, Electronic
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 20
    Publikationsdatum: 2011-04-23
    Beschreibung: Cellular messenger RNA levels are achieved by the combinatorial complexity of factors controlling transcription, yet the small number of molecules involved in these pathways fluctuates stochastically. It has not yet been experimentally possible to observe the activity of single polymerases on an endogenous gene to elucidate how these events occur in vivo. Here, we describe a method of fluctuation analysis of fluorescently labeled RNA to measure dynamics of nascent RNA--including initiation, elongation, and termination--at an active yeast locus. We find no transcriptional memory between initiation events, and elongation speed can vary by threefold throughout the cell cycle. By measuring the abundance and intranuclear mobility of an upstream transcription factor, we observe that the gene firing rate is directly determined by trans-activating factor search times.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152976/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152976/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Larson, Daniel R -- Zenklusen, Daniel -- Wu, Bin -- Chao, Jeffrey A -- Singer, Robert H -- 57071/PHS HHS/ -- 86217/PHS HHS/ -- R01 GM057071/GM/NIGMS NIH HHS/ -- R01 GM057071-10/GM/NIGMS NIH HHS/ -- R01 GM057071-11/GM/NIGMS NIH HHS/ -- R01 GM057071-12/GM/NIGMS NIH HHS/ -- R01 GM086217/GM/NIGMS NIH HHS/ -- R01 GM086217-01/GM/NIGMS NIH HHS/ -- R01 GM086217-02/GM/NIGMS NIH HHS/ -- R01 GM086217-03/GM/NIGMS NIH HHS/ -- R01 GM086217-04/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2011 Apr 22;332(6028):475-8. doi: 10.1126/science.1202142.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21512033" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphatases/genetics ; Cell Cycle ; Cell Nucleus/metabolism ; DNA Polymerase I/genetics ; Facilitated Diffusion ; *Genes, Fungal ; Glutamate Synthase/genetics ; Green Fluorescent Proteins ; Kinetics ; Microscopy, Fluorescence ; Models, Genetic ; Promoter Regions, Genetic ; RNA Polymerase II/metabolism ; RNA Precursors/genetics/metabolism ; RNA, Fungal/biosynthesis/*genetics ; RNA, Messenger/biosynthesis/*genetics ; Saccharomyces cerevisiae/*genetics/metabolism ; Saccharomyces cerevisiae Proteins/genetics/metabolism ; Spectrometry, Fluorescence ; Transcription Factors/metabolism ; *Transcription, Genetic ; Transcriptional Activation
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 21
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2011-07-09
    Beschreibung: Both engineering and evolution are constrained by trade-offs between efficiency and robustness, but theory that formalizes this fact is limited. For a simple two-state model of glycolysis, we explicitly derive analytic equations for hard trade-offs between robustness and efficiency with oscillations as an inevitable side effect. The model describes how the trade-offs arise from individual parameters, including the interplay of feedback control with autocatalysis of network products necessary to power and catalyze intermediate reactions. We then use control theory to prove that the essential features of these hard trade-off "laws" are universal and fundamental, in that they depend minimally on the details of this system and generalize to the robust efficiency of any autocatalytic network. The theory also suggests worst-case conditions that are consistent with initial experiments.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chandra, Fiona A -- Buzi, Gentian -- Doyle, John C -- R01GM078992A/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2011 Jul 8;333(6039):187-92. doi: 10.1126/science.1200705.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bioengineering, California Institute of Technology, Pasadena, CA 91125, USA. fiona@caltech.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21737735" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Monophosphate/metabolism ; Adenosine Triphosphate/metabolism ; Allosteric Regulation ; Biocatalysis ; Feedback, Physiological ; Glucose/metabolism ; *Glycolysis ; Kinetics ; Linear Models ; *Models, Biological ; NAD/metabolism ; Nonlinear Dynamics ; Phosphofructokinases/antagonists & inhibitors/metabolism ; Pyruvate Kinase/antagonists & inhibitors/metabolism ; Saccharomyces cerevisiae/*metabolism ; Single-Cell Analysis
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 22
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2011-04-23
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nair, Gautham -- Raj, Arjun -- New York, N.Y. -- Science. 2011 Apr 22;332(6028):431-2. doi: 10.1126/science.1205995.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21512026" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; DNA-Directed RNA Polymerases/metabolism ; Fibroblasts ; *Gene Expression ; *Gene Silencing ; Genes, Fungal ; Kinetics ; Mice ; Models, Genetic ; RNA, Messenger/*genetics/metabolism ; Signal Processing, Computer-Assisted ; Stochastic Processes ; *Transcription, Genetic ; *Transcriptional Activation ; Yeasts/genetics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 23
    Publikationsdatum: 2011-03-12
    Beschreibung: The spliceosome is the complex macromolecular machine responsible for removing introns from precursors to messenger RNAs (pre-mRNAs). We combined yeast genetic engineering, chemical biology, and multiwavelength fluorescence microscopy to follow assembly of single spliceosomes in real time in whole-cell extracts. We find that individual spliceosomal subcomplexes associate with pre-mRNA sequentially via an ordered pathway to yield functional spliceosomes and that association of every subcomplex is reversible. Further, early subcomplex binding events do not fully commit a pre-mRNA to splicing; rather, commitment increases as assembly proceeds. These findings have important implications for the regulation of alternative splicing. This experimental strategy should prove widely useful for mechanistic analysis of other macromolecular machines in environments approaching the complexity of living cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086749/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086749/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hoskins, Aaron A -- Friedman, Larry J -- Gallagher, Sarah S -- Crawford, Daniel J -- Anderson, Eric G -- Wombacher, Richard -- Ramirez, Nicholas -- Cornish, Virginia W -- Gelles, Jeff -- Moore, Melissa J -- F32 GM079971/GM/NIGMS NIH HHS/ -- F32 GM079971-03/GM/NIGMS NIH HHS/ -- GM079971/GM/NIGMS NIH HHS/ -- GM759628/GM/NIGMS NIH HHS/ -- K99 GM086471/GM/NIGMS NIH HHS/ -- K99 GM086471-02/GM/NIGMS NIH HHS/ -- K99/R00 GM086471/GM/NIGMS NIH HHS/ -- R01 GM043369/GM/NIGMS NIH HHS/ -- R01 GM053007/GM/NIGMS NIH HHS/ -- R01 GM053007-15/GM/NIGMS NIH HHS/ -- R01 GM081648/GM/NIGMS NIH HHS/ -- R01 GM081648-04/GM/NIGMS NIH HHS/ -- R01 GM54469/GM/NIGMS NIH HHS/ -- R01 GM81648/GM/NIGMS NIH HHS/ -- R37 GM043369/GM/NIGMS NIH HHS/ -- R37 GM043369-21/GM/NIGMS NIH HHS/ -- RC1 GM091804/GM/NIGMS NIH HHS/ -- RC1 GM091804-02/GM/NIGMS NIH HHS/ -- T32 GM007596/GM/NIGMS NIH HHS/ -- T32 GM007596-30/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2011 Mar 11;331(6022):1289-95. doi: 10.1126/science.1198830.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21393538" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphate/metabolism ; Fluorescent Dyes ; Introns ; Kinetics ; Microscopy, Fluorescence ; Protein Binding ; RNA Precursors/*metabolism ; *RNA Splicing ; RNA, Fungal/*metabolism ; Ribonucleoprotein, U1 Small Nuclear/metabolism ; Ribonucleoprotein, U2 Small Nuclear/metabolism ; Ribonucleoprotein, U4-U6 Small Nuclear/metabolism ; Ribonucleoprotein, U5 Small Nuclear/metabolism ; Ribonucleoproteins, Small Nuclear/*metabolism ; Saccharomyces cerevisiae/genetics/*metabolism/ultrastructure ; Saccharomyces cerevisiae Proteins/*metabolism ; Spliceosomes/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 24
    Publikationsdatum: 2011-09-24
    Beschreibung: Nonhexameric helicases use adenosine triphosphate (ATP) to unzip base pairs in double-stranded nucleic acids (dsNAs). Studies have suggested that these helicases unzip dsNAs in single-base pair increments, consuming one ATP molecule per base pair, but direct evidence for this mechanism is lacking. We used optical tweezers to follow the unwinding of double-stranded RNA by the hepatitis C virus NS3 helicase. Single-base pair steps by NS3 were observed, along with nascent nucleotide release that was asynchronous with base pair opening. Asynchronous release of nascent nucleotides rationalizes various observations of its dsNA unwinding and may be used to coordinate the translocation speed of NS3 along the RNA during viral replication.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4172460/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4172460/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cheng, Wei -- Arunajadai, Srikesh G -- Moffitt, Jeffrey R -- Tinoco, Ignacio Jr -- Bustamante, Carlos -- 5R01GM010840/GM/NIGMS NIH HHS/ -- 5R01GM032543/GM/NIGMS NIH HHS/ -- R01 GM010840/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2011 Sep 23;333(6050):1746-9. doi: 10.1126/science.1206023.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA. chengwe@umich.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21940894" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphate/metabolism ; Algorithms ; Base Pairing ; Hepacivirus/*enzymology ; Kinetics ; Models, Biological ; Nucleic Acid Conformation ; Optical Tweezers ; RNA Helicases/*metabolism ; RNA, Double-Stranded/chemistry/*metabolism ; RNA, Viral/chemistry/*metabolism ; Viral Nonstructural Proteins/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 25
    Publikationsdatum: 2011-03-19
    Beschreibung: In prokaryotes and eukaryotes, most genes appear to be transcribed during short periods called transcriptional bursts, interspersed by silent intervals. We describe how such bursts generate gene-specific temporal patterns of messenger RNA (mRNA) synthesis in mammalian cells. To monitor transcription at high temporal resolution, we established various gene trap cell lines and transgenic cell lines expressing a short-lived luciferase protein from an unstable mRNA, and recorded bioluminescence in real time in single cells. Mathematical modeling identified gene-specific on- and off-switching rates in transcriptional activity and mean numbers of mRNAs produced during the bursts. Transcriptional kinetics were markedly altered by cis-regulatory DNA elements. Our analysis demonstrated that bursting kinetics are highly gene-specific, reflecting refractory periods during which genes stay inactive for a certain time before switching on again.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Suter, David M -- Molina, Nacho -- Gatfield, David -- Schneider, Kim -- Schibler, Ueli -- Naef, Felix -- New York, N.Y. -- Science. 2011 Apr 22;332(6028):472-4. doi: 10.1126/science.1198817. Epub 2011 Mar 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Sciences III, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21415320" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Acetylation ; Animals ; Cells, Cultured ; Chromatin/physiology ; Circadian Rhythm/genetics ; Down-Regulation ; *Gene Expression ; Histones/metabolism ; Kinetics ; Luminescent Measurements ; Mice ; Models, Genetic ; NIH 3T3 Cells ; Promoter Regions, Genetic ; Protein Biosynthesis ; RNA, Messenger/genetics/metabolism ; Stochastic Processes ; *Transcription, Genetic ; Transcriptional Activation ; Transgenes ; Up-Regulation
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 26
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2011-10-29
    Beschreibung: An outstanding challenge in the field of molecular biology has been to understand the process by which proteins fold into their characteristic three-dimensional structures. Here, we report the results of atomic-level molecular dynamics simulations, over periods ranging between 100 mus and 1 ms, that reveal a set of common principles underlying the folding of 12 structurally diverse proteins. In simulations conducted with a single physics-based energy function, the proteins, representing all three major structural classes, spontaneously and repeatedly fold to their experimentally determined native structures. Early in the folding process, the protein backbone adopts a nativelike topology while certain secondary structure elements and a small number of nonlocal contacts form. In most cases, folding follows a single dominant route in which elements of the native structure appear in an order highly correlated with their propensity to form in the unfolded state.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lindorff-Larsen, Kresten -- Piana, Stefano -- Dror, Ron O -- Shaw, David E -- New York, N.Y. -- Science. 2011 Oct 28;334(6055):517-20. doi: 10.1126/science.1208351.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉D. E. Shaw Research, New York, NY 10036, USA. kresten.lindorff-larsen@DEShawResearch.com〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22034434" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Kinetics ; Molecular Dynamics Simulation ; Protein Conformation ; *Protein Folding ; Protein Structure, Secondary ; Proteins/*chemistry ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 27
    Publikationsdatum: 2011-10-15
    Beschreibung: Periodic stripe patterns are ubiquitous in living organisms, yet the underlying developmental processes are complex and difficult to disentangle. We describe a synthetic genetic circuit that couples cell density and motility. This system enabled programmed Escherichia coli cells to form periodic stripes of high and low cell densities sequentially and autonomously. Theoretical and experimental analyses reveal that the spatial structure arises from a recurrent aggregation process at the front of the continuously expanding cell population. The number of stripes formed could be tuned by modulating the basal expression of a single gene. The results establish motility control as a simple route to establishing recurrent structures without requiring an extrinsic pacemaker.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Chenli -- Fu, Xiongfei -- Liu, Lizhong -- Ren, Xiaojing -- Chau, Carlos K L -- Li, Sihong -- Xiang, Lu -- Zeng, Hualing -- Chen, Guanhua -- Tang, Lei-Han -- Lenz, Peter -- Cui, Xiaodong -- Huang, Wei -- Hwa, Terence -- Huang, Jian-Dong -- New York, N.Y. -- Science. 2011 Oct 14;334(6053):238-41. doi: 10.1126/science.1209042.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21998392" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Acyl-Butyrolactones/metabolism ; Bacterial Load ; Cell Proliferation ; Culture Media ; Diffusion ; Escherichia coli K12/cytology/genetics/*growth & development/*physiology ; Gene Expression Regulation, Bacterial ; Gene Regulatory Networks ; Kinetics ; Models, Biological ; Movement ; Quorum Sensing ; Synthetic Biology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 28
    Publikationsdatum: 2011-04-23
    Beschreibung: Amination of alkanes has generally required metal catalysts and/or high temperatures. Here we report that simple exposure of a broad range of alkanes to N-triflylimino-lambda(3)-bromane 1 at ambient temperature results in C-H insertion of the nitrogen functionality to afford triflyl-substituted amines in moderate to high yields. Marked selectivity for tertiary over secondary C-H bonds was observed; primary (methyl) C-H bonds were inert. Addition of hexafluoroisopropanol to inhibit decomposition of 1 dramatically improved the C-H amination efficiencies. Second-order kinetics, activation parameters (negative activation entropy), deuterium isotope effects, and theoretical calculations suggest a concerted asynchronous bimolecular transition state for the metal-free C-H amination event.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ochiai, Masahito -- Miyamoto, Kazunori -- Kaneaki, Takao -- Hayashi, Satoko -- Nakanishi, Waro -- New York, N.Y. -- Science. 2011 Apr 22;332(6028):448-51. doi: 10.1126/science.1201686.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan. mochiai@ph.tokushima-u.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21512029" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adamantane/chemistry ; Alkanes/*chemistry ; Amination ; Amines/*chemistry ; Bromobenzenes/*chemistry ; Carbon/chemistry ; Hydrocarbons, Brominated/*chemistry ; Hydrogen/chemistry ; Kinetics ; Physicochemical Processes ; Stereoisomerism ; Temperature ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 29
    Publikationsdatum: 2011-04-09
    Beschreibung: Conformational dynamics play a key role in enzyme catalysis. Although protein motions have clear implications for ligand flux, a role for dynamics in the chemical step of enzyme catalysis has not been clearly established. We generated a mutant of Escherichia coli dihydrofolate reductase that abrogates millisecond-time-scale fluctuations in the enzyme active site without perturbing its structural and electrostatic preorganization. This dynamic knockout severely impairs hydride transfer. Thus, we have found a link between conformational fluctuations on the millisecond time scale and the chemical step of an enzymatic reaction, with broad implications for our understanding of enzyme mechanisms and for design of novel protein catalysts.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3151171/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3151171/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bhabha, Gira -- Lee, Jeeyeon -- Ekiert, Damian C -- Gam, Jongsik -- Wilson, Ian A -- Dyson, H Jane -- Benkovic, Stephen J -- Wright, Peter E -- GM080209/GM/NIGMS NIH HHS/ -- GM75995/GM/NIGMS NIH HHS/ -- R01 GM075995/GM/NIGMS NIH HHS/ -- U54 GM094586/GM/NIGMS NIH HHS/ -- Y1-CO-1020/CO/NCI NIH HHS/ -- Y1-GM-1104/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2011 Apr 8;332(6026):234-8. doi: 10.1126/science.1198542.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21474759" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amino Acid Sequence ; Biocatalysis ; Catalytic Domain ; Crystallography, X-Ray ; Escherichia coli/*enzymology ; Folic Acid/chemistry ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Mutant Proteins/chemistry/metabolism ; NADP/chemistry ; Protein Conformation ; Tetrahydrofolate Dehydrogenase/*chemistry/genetics/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 30
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2011-03-19
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bradforth, Stephen -- New York, N.Y. -- Science. 2011 Mar 18;331(6023):1398-9. doi: 10.1126/science.1203629.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA. stephen.bradforth@usc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21415344" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Chemical Phenomena ; Cyclohexanes/*chemistry ; Free Radicals ; Hydrogen/*chemistry ; Hydrogen Cyanide/*chemistry ; Kinetics ; Solutions ; Solvents/chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 31
    Publikationsdatum: 2011-09-03
    Beschreibung: A deeper mechanistic understanding of the saccharification of cellulosic biomass could enhance the efficiency of biofuels development. We report here the real-time visualization of crystalline cellulose degradation by individual cellulase enzymes through use of an advanced version of high-speed atomic force microscopy. Trichoderma reesei cellobiohydrolase I (TrCel7A) molecules were observed to slide unidirectionally along the crystalline cellulose surface but at one point exhibited collective halting analogous to a traffic jam. Changing the crystalline polymorphic form of cellulose by means of an ammonia treatment increased the apparent number of accessible lanes on the crystalline surface and consequently the number of moving cellulase molecules. Treatment of this bulky crystalline cellulose simultaneously or separately with T. reesei cellobiohydrolase II (TrCel6A) resulted in a remarkable increase in the proportion of mobile enzyme molecules on the surface. Cellulose was completely degraded by the synergistic action between the two enzymes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Igarashi, Kiyohiko -- Uchihashi, Takayuki -- Koivula, Anu -- Wada, Masahisa -- Kimura, Satoshi -- Okamoto, Tetsuaki -- Penttila, Merja -- Ando, Toshio -- Samejima, Masahiro -- New York, N.Y. -- Science. 2011 Sep 2;333(6047):1279-82. doi: 10.1126/science.1208386.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan. aquarius@mail.ecc.u-tokyo.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21885779" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adsorption ; Biomass ; Cellobiose/metabolism ; Cellulose/chemistry/*metabolism ; Cellulose 1,4-beta-Cellobiosidase/*metabolism ; Crystallization ; Hydrolysis ; Kinetics ; Microscopy, Atomic Force ; Trichoderma/enzymology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 32
    Publikationsdatum: 2011-06-11
    Beschreibung: Aromatic molecules are key constituents of many pharmaceuticals, electronic materials, and commodity plastics. The utility of these molecules directly reflects the identity and pattern of substituents on the aromatic ring. Here, we report a palladium(II) catalyst system, incorporating an unconventional ortho-dimethylaminopyridine ligand, for the conversion of substituted cyclohexanones to the corresponding phenols. The reaction proceeds via successive dehydrogenation of two saturated carbon-carbon bonds of the six-membered ring and uses molecular oxygen as the hydrogen acceptor. This reactivity demonstrates a versatile and efficient strategy for the synthesis of substituted aromatic molecules with fundamentally different selectivity constraints from the numerous known synthetic methods that rely on substitution of a preexisting aromatic ring.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174491/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174491/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Izawa, Yusuke -- Pun, Doris -- Stahl, Shannon S -- RC1 GM091161/GM/NIGMS NIH HHS/ -- RC1 GM091161-01/GM/NIGMS NIH HHS/ -- RC1 GM091161-02/GM/NIGMS NIH HHS/ -- RC1-GM091161/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2011 Jul 8;333(6039):209-13. doi: 10.1126/science.1204183. Epub 2011 Jun 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21659567" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Aerobiosis ; Catalysis ; Cyclohexanones/*chemistry ; Hydrogen/chemistry ; Kinetics ; Ligands ; Molecular Structure ; Organic Chemistry Processes ; Palladium/*chemistry ; Phenols/*chemical synthesis/*chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 33
    Publikationsdatum: 2011-02-05
    Beschreibung: Solvent collisions can often mask initial disposition of energy to the products of solution-phase chemical reactions. Here, we show with transient infrared absorption spectra obtained with picosecond time resolution that the nascent HCN products of reaction of CN radicals with cyclohexane in chlorinated organic solvents exhibit preferential excitation of one quantum of the C-H stretching mode and up to two quanta of the bending mode. On time scales of approximately 100 to 300 picoseconds, the HCN products undergo relaxation to the vibrational ground state by coupling to the solvent bath. Comparison with reactions of CN radicals with alkanes in the gas phase, known to produce HCN with greater C-H stretch and bending mode excitation (up to two and approximately six quanta, respectively), indicates partial damping of the nascent product vibrational motion by the solvent. The transient infrared spectra therefore probe solvent-induced modifications to the reaction free energy surface and chemical dynamics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Greaves, Stuart J -- Rose, Rebecca A -- Oliver, Thomas A A -- Glowacki, David R -- Ashfold, Michael N R -- Harvey, Jeremy N -- Clark, Ian P -- Greetham, Gregory M -- Parker, Anthony W -- Towrie, Michael -- Orr-Ewing, Andrew J -- ST/501784/Biotechnology and Biological Sciences Research Council/United Kingdom -- New York, N.Y. -- Science. 2011 Mar 18;331(6023):1423-6. doi: 10.1126/science.1197796. Epub 2011 Feb 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21292937" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Chemical Phenomena ; Cyclohexanes/*chemistry ; Free Radicals ; Hydrogen/*chemistry ; Hydrogen Cyanide/*chemistry ; Kinetics ; Models, Chemical ; Physicochemical Processes ; Solutions ; Solvents/chemistry ; Spectrophotometry, Infrared
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 34
    Publikationsdatum: 2011-10-29
    Beschreibung: Direct observation of the detailed conformational fluctuations of a single protein molecule en route to its folded state has so far been realized only in silico. We have used single-molecule force spectroscopy to study the folding transitions of single calmodulin molecules. High-resolution optical tweezers assays in combination with hidden Markov analysis reveal a complex network of on- and off-pathway intermediates. Cooperative and anticooperative interactions across domain boundaries can be observed directly. The folding network involves four intermediates. Two off-pathway intermediates exhibit non-native interdomain interactions and compete with the ultrafast productive folding pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stigler, Johannes -- Ziegler, Fabian -- Gieseke, Anja -- Gebhardt, J Christof M -- Rief, Matthias -- New York, N.Y. -- Science. 2011 Oct 28;334(6055):512-6. doi: 10.1126/science.1207598.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Physik Department E22, Technische Universitat Munchen, James-Franck-Strasse, 85748 Garching, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22034433" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Calcium/chemistry ; Calmodulin/*chemistry ; Kinetics ; Markov Chains ; Optical Tweezers ; Protein Conformation ; Protein Folding ; Protein Structure, Tertiary ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 35
    Publikationsdatum: 2011-11-15
    Beschreibung: Silent information regulator 2 (Sir2) proteins (sirtuins) are nicotinamide adenine dinucleotide-dependent deacetylases that regulate important biological processes. Mammals have seven sirtuins, Sirt1 to Sirt7. Four of them (Sirt4 to Sirt7) have no detectable or very weak deacetylase activity. We found that Sirt5 is an efficient protein lysine desuccinylase and demalonylase in vitro. The preference for succinyl and malonyl groups was explained by the presence of an arginine residue (Arg(105)) and tyrosine residue (Tyr(102)) in the acyl pocket of Sirt5. Several mammalian proteins were identified with mass spectrometry to have succinyl or malonyl lysine modifications. Deletion of Sirt5 in mice appeared to increase the level of succinylation on carbamoyl phosphate synthase 1, which is a known target of Sirt5. Thus, protein lysine succinylation may represent a posttranslational modification that can be reversed by Sirt5 in vivo.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217313/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217313/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Du, Jintang -- Zhou, Yeyun -- Su, Xiaoyang -- Yu, Jiu Jiu -- Khan, Saba -- Jiang, Hong -- Kim, Jungwoo -- Woo, Jimin -- Kim, Jun Huyn -- Choi, Brian Hyun -- He, Bin -- Chen, Wei -- Zhang, Sheng -- Cerione, Richard A -- Auwerx, Johan -- Hao, Quan -- Lin, Hening -- 231138/European Research Council/International -- DK58920/DK/NIDDK NIH HHS/ -- P41 RR001646/RR/NCRR NIH HHS/ -- P41 RR001646-27/RR/NCRR NIH HHS/ -- R01 GM086703/GM/NIGMS NIH HHS/ -- R01 GM086703-03/GM/NIGMS NIH HHS/ -- R01 GM086703-03S1/GM/NIGMS NIH HHS/ -- R01GM086703/GM/NIGMS NIH HHS/ -- RR01646/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2011 Nov 11;334(6057):806-9. doi: 10.1126/science.1207861.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22076378" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Acetylation ; Animals ; Carbamoyl-Phosphate Synthase (Ammonia)/metabolism ; Cattle ; Crystallography, X-Ray ; Histones/metabolism ; Humans ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Lysine/*metabolism ; Male ; Mice ; Mice, Knockout ; Mitochondria, Liver/metabolism ; NAD/metabolism ; Peptides/*metabolism ; Protein Processing, Post-Translational ; Sirtuins/chemistry/genetics/*metabolism ; Succinic Acid/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 36
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2011-12-24
    Beschreibung: DNA replication machineries have been studied extensively, but the kinetics of action of their components remains largely unknown. We report a study of DNA synthesis during replication in living Escherichia coli cells. Using single-molecule microscopy, we observed repetitive fluorescence bursts of single polymerase IIIs (Pol IIIs), indicating polymerase exchange at the replication fork. Fluctuations in the amount of DNA-bound single-stranded DNA-binding protein (SSB) reflect different speeds for the leading- and lagging-strand DNA polymerases. Coincidence analyses of Pol III and SSB fluctuations show that they correspond to the lagging-strand synthesis and suggest the use of a new Pol III for each Okazaki fragment. Based on exchanges involving two Pol IIIs, we propose that the third polymerase in the replisome is involved in lagging-strand synthesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lia, Giuseppe -- Michel, Benedicte -- Allemand, Jean-Francois -- New York, N.Y. -- Science. 2012 Jan 20;335(6066):328-31. doi: 10.1126/science.1210400. Epub 2011 Dec 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CNRS, Centre de Genetique Moleculaire, UPR3404, Gif-sur-Yvette F-91198, France. lia@cgm.cnrs-gif.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22194411" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Bacterial Proteins/metabolism ; DNA/*biosynthesis ; DNA Polymerase III/*metabolism ; *DNA Replication ; DNA, Bacterial/*biosynthesis ; DNA, Single-Stranded/metabolism ; DNA-Binding Proteins/*metabolism ; Escherichia coli/*metabolism ; Escherichia coli Proteins/*metabolism ; Fluorescence ; Kinetics ; Luminescent Proteins/metabolism ; Models, Biological ; Photobleaching ; Recombinant Fusion Proteins/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 37
    Publikationsdatum: 2010-05-22
    Beschreibung: Cell surface receptors convert extracellular cues into receptor activation, thereby triggering intracellular signaling networks and controlling cellular decisions. A major unresolved issue is the identification of receptor properties that critically determine processing of ligand-encoded information. We show by mathematical modeling of quantitative data and experimental validation that rapid ligand depletion and replenishment of the cell surface receptor are characteristic features of the erythropoietin (Epo) receptor (EpoR). The amount of Epo-EpoR complexes and EpoR activation integrated over time corresponds linearly to ligand input; this process is carried out over a broad range of ligand concentrations. This relation depends solely on EpoR turnover independent of ligand binding, which suggests an essential role of large intracellular receptor pools. These receptor properties enable the system to cope with basal and acute demand in the hematopoietic system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Becker, Verena -- Schilling, Marcel -- Bachmann, Julie -- Baumann, Ute -- Raue, Andreas -- Maiwald, Thomas -- Timmer, Jens -- Klingmuller, Ursula -- New York, N.Y. -- Science. 2010 Jun 11;328(5984):1404-8. doi: 10.1126/science.1184913. Epub 2010 May 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division Systems Biology of Signal Transduction, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120 Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20488988" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Cell Line ; Cell Membrane/*metabolism ; Computer Simulation ; Endocytosis ; Epoetin Alfa ; Erythropoietin/metabolism/pharmacology ; Kinetics ; Ligands ; Mice ; Models, Biological ; Protein Binding ; Receptors, Erythropoietin/*metabolism ; Recombinant Proteins ; Signal Transduction
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 38
    Publikationsdatum: 2010-09-11
    Beschreibung: Fungal degradation of plant biomass may provide insights for improving cellulosic biofuel production. We show that the model cellulolytic fungus Neurospora crassa relies on a high-affinity cellodextrin transport system for rapid growth on cellulose. Reconstitution of the N. crassa cellodextrin transport system in Saccharomyces cerevisiae promotes efficient growth of this yeast on cellodextrins. In simultaneous saccharification and fermentation experiments, the engineered yeast strains more rapidly convert cellulose to ethanol when compared with yeast lacking this system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Galazka, Jonathan M -- Tian, Chaoguang -- Beeson, William T -- Martinez, Bruno -- Glass, N Louise -- Cate, Jamie H D -- New York, N.Y. -- Science. 2010 Oct 1;330(6000):84-6. doi: 10.1126/science.1192838. Epub 2010 Sep 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20829451" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): *Biofuels ; Biological Transport ; Biomass ; Cellobiose/metabolism ; Cellulase/metabolism ; Cellulose/*analogs & derivatives/*metabolism ; Dextrins/*metabolism ; Ethanol/metabolism ; Fermentation ; Fungal Proteins/genetics/*metabolism ; Genetic Engineering ; Kinetics ; Membrane Transport Proteins/genetics/*metabolism ; Neurospora crassa/genetics/growth & development/*metabolism ; Saccharomyces cerevisiae/genetics/growth & development/*metabolism ; Saccharomyces cerevisiae Proteins/metabolism ; beta-Glucosidase/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 39
    Publikationsdatum: 2010-07-10
    Beschreibung: Self-organization of nanoparticles is an efficient strategy for producing nanostructures with complex, hierarchical architectures. The past decade has witnessed great progress in nanoparticle self-assembly, yet the quantitative prediction of the architecture of nanoparticle ensembles and of the kinetics of their formation remains a challenge. We report on the marked similarity between the self-assembly of metal nanoparticles and reaction-controlled step-growth polymerization. The nanoparticles act as multifunctional monomer units, which form reversible, noncovalent bonds at specific bond angles and organize themselves into a colloidal polymer. We show that the kinetics and statistics of step-growth polymerization enable a quantitative prediction of the architecture of linear, branched, and cyclic self-assembled nanostructures; their aggregation numbers and size distribution; and the formation of structural isomers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Kun -- Nie, Zhihong -- Zhao, Nana -- Li, Wei -- Rubinstein, Michael -- Kumacheva, Eugenia -- 1-R01-HL077546-03A2/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 2010 Jul 9;329(5988):197-200. doi: 10.1126/science.1189457.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20616274" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Cetrimonium Compounds/chemistry ; Colloids ; Cyclization ; Gold ; Isomerism ; Kinetics ; Metal Nanoparticles/*chemistry ; Microscopy, Electron, Transmission ; Nanotechnology/methods ; Physicochemical Processes ; Polymers ; Polystyrenes/chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 40
    Publikationsdatum: 2010-09-18
    Beschreibung: Proliferating cells, including cancer cells, require altered metabolism to efficiently incorporate nutrients such as glucose into biomass. The M2 isoform of pyruvate kinase (PKM2) promotes the metabolism of glucose by aerobic glycolysis and contributes to anabolic metabolism. Paradoxically, decreased pyruvate kinase enzyme activity accompanies the expression of PKM2 in rapidly dividing cancer cells and tissues. We demonstrate that phosphoenolpyruvate (PEP), the substrate for pyruvate kinase in cells, can act as a phosphate donor in mammalian cells because PEP participates in the phosphorylation of the glycolytic enzyme phosphoglycerate mutase (PGAM1) in PKM2-expressing cells. We used mass spectrometry to show that the phosphate from PEP is transferred to the catalytic histidine (His11) on human PGAM1. This reaction occurred at physiological concentrations of PEP and produced pyruvate in the absence of PKM2 activity. The presence of histidine-phosphorylated PGAM1 correlated with the expression of PKM2 in cancer cell lines and tumor tissues. Thus, decreased pyruvate kinase activity in PKM2-expressing cells allows PEP-dependent histidine phosphorylation of PGAM1 and may provide an alternate glycolytic pathway that decouples adenosine triphosphate production from PEP-mediated phosphotransfer, allowing for the high rate of glycolysis to support the anabolic metabolism observed in many proliferating cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030121/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030121/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vander Heiden, Matthew G -- Locasale, Jason W -- Swanson, Kenneth D -- Sharfi, Hadar -- Heffron, Greg J -- Amador-Noguez, Daniel -- Christofk, Heather R -- Wagner, Gerhard -- Rabinowitz, Joshua D -- Asara, John M -- Cantley, Lewis C -- 1K08CA136983/CA/NCI NIH HHS/ -- 1P01CA120964-01A/CA/NCI NIH HHS/ -- 5 T32 CA009361-28/CA/NCI NIH HHS/ -- 5P30CA006516-43/CA/NCI NIH HHS/ -- K08 CA136983/CA/NCI NIH HHS/ -- K08 CA136983-02/CA/NCI NIH HHS/ -- P01 CA089021/CA/NCI NIH HHS/ -- P01 CA089021-10/CA/NCI NIH HHS/ -- P01 CA120964/CA/NCI NIH HHS/ -- P01 CA120964-01A1/CA/NCI NIH HHS/ -- P01 GM047467/GM/NIGMS NIH HHS/ -- P01 GM047467-20/GM/NIGMS NIH HHS/ -- P01CA089021/CA/NCI NIH HHS/ -- P01GM047467/GM/NIGMS NIH HHS/ -- P30 CA006516/CA/NCI NIH HHS/ -- P30 CA006516-43S1/CA/NCI NIH HHS/ -- R01 AI078063/AI/NIAID NIH HHS/ -- R01 GM056203/GM/NIGMS NIH HHS/ -- R01-GM56302/GM/NIGMS NIH HHS/ -- R21 CA128620/CA/NCI NIH HHS/ -- R21/R33 DK070299/DK/NIDDK NIH HHS/ -- R33 DK070299/DK/NIDDK NIH HHS/ -- R33 DK070299-03/DK/NIDDK NIH HHS/ -- T32 CA009172/CA/NCI NIH HHS/ -- T32 CA009361/CA/NCI NIH HHS/ -- T32 CA009361-28/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2010 Sep 17;329(5998):1492-9. doi: 10.1126/science.1188015.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Dana Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20847263" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphate/metabolism ; Animals ; Cell Line ; Cell Line, Tumor ; *Cell Proliferation ; Female ; Glucose/*metabolism ; Glyceric Acids/metabolism ; *Glycolysis ; Histidine/metabolism ; Humans ; Isoenzymes/metabolism ; Kinetics ; Male ; Mammary Neoplasms, Animal/metabolism ; Mice ; Neoplasms/*metabolism/pathology ; Phosphoenolpyruvate/metabolism ; Phosphoglycerate Mutase/*metabolism ; Phosphopyruvate Hydratase/metabolism ; Phosphorylation ; Prostatic Neoplasms/metabolism ; Pyruvate Kinase/*metabolism ; Pyruvic Acid/metabolism ; Recombinant Proteins/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 41
    Publikationsdatum: 2010-12-15
    Beschreibung: Alzheimer's disease is hypothesized to be caused by an imbalance between beta-amyloid (Abeta) production and clearance that leads to Abeta accumulation in the central nervous system (CNS). Abeta production and clearance are key targets in the development of disease-modifying therapeutic agents for Alzheimer's disease. However, there has not been direct evidence of altered Abeta production or clearance in Alzheimer's disease. By using metabolic labeling, we measured Abeta42 and Abeta40 production and clearance rates in the CNS of participants with Alzheimer's disease and cognitively normal controls. Clearance rates for both Abeta42 and Abeta40 were impaired in Alzheimer's disease compared with controls. On average, there were no differences in Abeta40 or Abeta42 production rates. Thus, the common late-onset form of Alzheimer's disease is characterized by an overall impairment in Abeta clearance.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3073454/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3073454/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mawuenyega, Kwasi G -- Sigurdson, Wendy -- Ovod, Vitaliy -- Munsell, Ling -- Kasten, Tom -- Morris, John C -- Yarasheski, Kevin E -- Bateman, Randall J -- K08 AG027091/AG/NIA NIH HHS/ -- K08 AG027091-03/AG/NIA NIH HHS/ -- K23 AG030946/AG/NIA NIH HHS/ -- K23 AG030946-04/AG/NIA NIH HHS/ -- P01 AG003991/AG/NIA NIH HHS/ -- P01 AG003991-28/AG/NIA NIH HHS/ -- P01 AG03991/AG/NIA NIH HHS/ -- P30 DK056341/DK/NIDDK NIH HHS/ -- P30 DK056341-10/DK/NIDDK NIH HHS/ -- P41 GM103422/GM/NIGMS NIH HHS/ -- P41 RR000954/RR/NCRR NIH HHS/ -- P41 RR000954-34/RR/NCRR NIH HHS/ -- P50 AG005681/AG/NIA NIH HHS/ -- P50 AG005681-28/AG/NIA NIH HHS/ -- P50 AG05681/AG/NIA NIH HHS/ -- P60 DK020579/DK/NIDDK NIH HHS/ -- P60 DK020579-31/DK/NIDDK NIH HHS/ -- R01 NS065667/NS/NINDS NIH HHS/ -- R01 NS065667-03/NS/NINDS NIH HHS/ -- UL1 RR024992/RR/NCRR NIH HHS/ -- UL1 RR024992-05/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2010 Dec 24;330(6012):1774. doi: 10.1126/science.1197623. Epub 2010 Dec 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21148344" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Aged ; Aged, 80 and over ; Alzheimer Disease/cerebrospinal fluid/*metabolism ; Amyloid beta-Peptides/cerebrospinal fluid/*metabolism ; Brain/*metabolism ; Female ; Humans ; Kinetics ; Male ; Middle Aged ; Peptide Fragments/cerebrospinal fluid/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 42
    Publikationsdatum: 2010-06-05
    Beschreibung: Despite the widespread use of axially chiral, or atropisomeric, biaryl ligands in modern synthesis and the occurrence of numerous natural products exhibiting axial chirality, few catalytic methods have emerged for the direct asymmetric preparation of this compound class. Here, we present a tripeptide-derived small-molecule catalyst for the dynamic kinetic resolution of racemic biaryl substrates. The reaction proceeds via an atropisomer-selective electrophilic aromatic substitution reaction using simple bromination reagents. The result is an enantioselective synthesis that delivers chiral nonracemic biaryl compounds with excellent optical purity and good isolated chemical yields (in most cases a 〉95:5 enantiomer ratio and isolated yields of 65 to 87%). A mechanistic model is advanced that accounts for the basis of selectivity observed.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066098/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066098/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gustafson, Jeffrey L -- Lim, Daniel -- Miller, Scott J -- GM068649/GM/NIGMS NIH HHS/ -- R01 GM068649/GM/NIGMS NIH HHS/ -- R01 GM068649-10/GM/NIGMS NIH HHS/ -- R37 GM068649/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2010 Jun 4;328(5983):1251-5. doi: 10.1126/science.1188403.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Yale University, 225 Prospect Street, Post Office Box 208107, New Haven, CT 06520-8107, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20522769" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Biphenyl Compounds/*chemical synthesis/chemistry ; Bromine/chemistry ; Catalysis ; *Halogenation ; Kinetics ; Ligands ; Molecular Structure ; Oligopeptides/*chemistry ; Physicochemical Processes ; *Stereoisomerism ; Temperature
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 43
    Publikationsdatum: 2010-10-16
    Beschreibung: Neutrophils are recruited from the blood to sites of sterile inflammation, where they contribute to wound healing but may also cause tissue damage. By using spinning disk confocal intravital microscopy, we examined the kinetics and molecular mechanisms of neutrophil recruitment to sites of focal hepatic necrosis in vivo. Adenosine triphosphate released from necrotic cells activated the Nlrp3 inflammasome to generate an inflammatory microenvironment that alerted circulating neutrophils to adhere within liver sinusoids. Subsequently, generation of an intravascular chemokine gradient directed neutrophil migration through healthy tissue toward foci of damage. Lastly, formyl-peptide signals released from necrotic cells guided neutrophils through nonperfused sinusoids into the injury. Thus, dynamic in vivo imaging revealed a multistep hierarchy of directional cues that guide neutrophil localization to sites of sterile inflammation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McDonald, Braedon -- Pittman, Keir -- Menezes, Gustavo B -- Hirota, Simon A -- Slaba, Ingrid -- Waterhouse, Christopher C M -- Beck, Paul L -- Muruve, Daniel A -- Kubes, Paul -- Canadian Institutes of Health Research/Canada -- New York, N.Y. -- Science. 2010 Oct 15;330(6002):362-6. doi: 10.1126/science.1195491.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Immunology Research Group, University of Calgary, Alberta T2N 4N1, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20947763" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphate/metabolism ; Animals ; Carrier Proteins/metabolism ; Cell Adhesion ; Chemokine CXCL2/metabolism ; Chemokines/metabolism ; Chemotaxis, Leukocyte ; Cues ; Endothelium, Vascular/physiology ; Inflammation/*immunology/metabolism/*pathology ; Kinetics ; Liver/blood supply/*immunology/metabolism/*pathology ; Liver Diseases/*immunology/metabolism/*pathology ; Macrophage-1 Antigen/physiology ; Mice ; Microscopy/methods ; Microscopy, Confocal ; Microvessels/physiology ; Necrosis ; *Neutrophil Infiltration ; Neutrophils/physiology ; Peptides/metabolism ; Receptors, Formyl Peptide/metabolism ; Receptors, Interleukin-8B/metabolism ; Receptors, Purinergic P2/metabolism ; Receptors, Purinergic P2X7 ; Signal Transduction
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 44
    Publikationsdatum: 2010-07-22
    Beschreibung: The Diels-Alder reaction is a cornerstone in organic synthesis, forming two carbon-carbon bonds and up to four new stereogenic centers in one step. No naturally occurring enzymes have been shown to catalyze bimolecular Diels-Alder reactions. We describe the de novo computational design and experimental characterization of enzymes catalyzing a bimolecular Diels-Alder reaction with high stereoselectivity and substrate specificity. X-ray crystallography confirms that the structure matches the design for the most active of the enzymes, and binding site substitutions reprogram the substrate specificity. Designed stereoselective catalysts for carbon-carbon bond-forming reactions should be broadly useful in synthetic chemistry.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3241958/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3241958/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Siegel, Justin B -- Zanghellini, Alexandre -- Lovick, Helena M -- Kiss, Gert -- Lambert, Abigail R -- St Clair, Jennifer L -- Gallaher, Jasmine L -- Hilvert, Donald -- Gelb, Michael H -- Stoddard, Barry L -- Houk, Kendall N -- Michael, Forrest E -- Baker, David -- R01 GM075962/GM/NIGMS NIH HHS/ -- T32 GM008268/GM/NIGMS NIH HHS/ -- T32 GM008268-24/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2010 Jul 16;329(5989):309-13. doi: 10.1126/science.1190239.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20647463" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Acrylamides/chemistry ; Algorithms ; Butadienes/chemistry ; Carbon/*chemistry ; Catalysis ; Catalytic Domain ; Computer Simulation ; *Computer-Aided Design ; Crystallography, X-Ray ; Enzymes/*chemistry/genetics ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Models, Molecular ; Mutagenesis ; Physicochemical Processes ; Protein Conformation ; *Protein Engineering ; Proteins/*chemistry/genetics ; Software ; Stereoisomerism ; Substrate Specificity
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    Publikationsdatum: 2010-09-11
    Beschreibung: Filopodia are finger-like protrusive structures, containing actin bundles. By incubating frog egg extracts with supported lipid bilayers containing phosphatidylinositol 4,5 bisphosphate, we have reconstituted the assembly of filopodia-like structures (FLSs). The actin assembles into parallel bundles, and known filopodial components localize to the tip and shaft. The filopodia tip complexes self-organize--they are not templated by preexisting membrane microdomains. The F-BAR domain protein toca-1 recruits N-WASP, followed by the Arp2/3 complex and actin. Elongation proteins, Diaphanous-related formin, VASP, and fascin are recruited subsequently. Although the Arp2/3 complex is required for FLS initiation, it is not essential for elongation, which involves formins. We propose that filopodia form via clustering of Arp2/3 complex activators, self-assembly of filopodial tip complexes on the membrane, and outgrowth of actin bundles.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2982780/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2982780/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, Kwonmoo -- Gallop, Jennifer L -- Rambani, Komal -- Kirschner, Marc W -- GM26875/GM/NIGMS NIH HHS/ -- R01 GM026875/GM/NIGMS NIH HHS/ -- R01 GM026875-34/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2010 Sep 10;329(5997):1341-5. doi: 10.1126/science.1191710.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20829485" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Actin Cytoskeleton/ultrastructure ; Actin-Related Protein 2-3 Complex/metabolism ; Actins/*metabolism ; Animals ; Carrier Proteins/metabolism ; Cell Adhesion Molecules/metabolism ; Cell Membrane/metabolism ; Humans ; Kinetics ; *Lipid Bilayers ; Membrane Microdomains ; Mice ; Microfilament Proteins/metabolism ; Microtubule-Associated Proteins/metabolism ; NADPH Dehydrogenase/metabolism ; Phosphatidylinositol Phosphates/metabolism ; Phosphoproteins/metabolism ; Pseudopodia/*metabolism/*ultrastructure ; Recombinant Fusion Proteins/metabolism ; Signal Transduction ; Wiskott-Aldrich Syndrome Protein, Neuronal/metabolism ; Xenopus ; Xenopus Proteins/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 46
    Publikationsdatum: 2010-05-08
    Beschreibung: Proper protein localization is essential for all cells. However, the precise mechanism by which high fidelity is achieved is not well understood for any protein-targeting pathway. To address this fundamental question, we investigated the signal recognition particle (SRP) pathway in Escherichia coli, which delivers proteins to the bacterial inner membrane through recognition of signal sequences on cargo proteins. Fidelity was thought to arise from the inability of SRP to bind strongly to incorrect cargos. Using biophysical assays, we found that incorrect cargos were also rejected through a series of checkpoints during subsequent steps of targeting. Thus, high fidelity of substrate selection is achieved through the cumulative effect of multiple checkpoints; this principle may be generally applicable to other pathways involving selective signal recognition.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3760334/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3760334/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Xin -- Rashid, Rumana -- Wang, Kai -- Shan, Shu-ou -- GM078024/GM/NIGMS NIH HHS/ -- R01 GM078024/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2010 May 7;328(5979):757-60. doi: 10.1126/science.1186743.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20448185" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Cell Membrane/metabolism ; Escherichia coli/*metabolism ; Escherichia coli Proteins/chemistry/*metabolism ; Fluorescence Resonance Energy Transfer ; Guanosine Triphosphate/metabolism ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Models, Biological ; Protein Binding ; Protein Biosynthesis ; *Protein Sorting Signals ; *Protein Transport ; Ribosomes/metabolism ; Signal Recognition Particle/*metabolism ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 47
    Publikationsdatum: 2010-10-16
    Beschreibung: Molecular dynamics (MD) simulations are widely used to study protein motions at an atomic level of detail, but they have been limited to time scales shorter than those of many biologically critical conformational changes. We examined two fundamental processes in protein dynamics--protein folding and conformational change within the folded state--by means of extremely long all-atom MD simulations conducted on a special-purpose machine. Equilibrium simulations of a WW protein domain captured multiple folding and unfolding events that consistently follow a well-defined folding pathway; separate simulations of the protein's constituent substructures shed light on possible determinants of this pathway. A 1-millisecond simulation of the folded protein BPTI reveals a small number of structurally distinct conformational states whose reversible interconversion is slower than local relaxations within those states by a factor of more than 1000.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shaw, David E -- Maragakis, Paul -- Lindorff-Larsen, Kresten -- Piana, Stefano -- Dror, Ron O -- Eastwood, Michael P -- Bank, Joseph A -- Jumper, John M -- Salmon, John K -- Shan, Yibing -- Wriggers, Willy -- New York, N.Y. -- Science. 2010 Oct 15;330(6002):341-6. doi: 10.1126/science.1187409.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉D. E. Shaw Research, 120 West 45th Street, New York, NY 10036, USA. David.Shaw@DEShawResearch.com〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20947758" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amino Acid Substitution ; Aprotinin/*chemistry ; Computational Biology ; Computers ; Kinetics ; Microfilament Proteins/chemistry ; Models, Molecular ; *Molecular Dynamics Simulation ; Mutant Proteins/chemistry ; *Protein Conformation ; *Protein Folding ; Protein Structure, Tertiary ; Proteins/*chemistry ; Solvents ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 48
    Publikationsdatum: 2010-01-23
    Beschreibung: Viruses are thought to spread across susceptible cells through an iterative process of infection, replication, and release, so that the rate of spread is limited by replication kinetics. Here, we show that vaccinia virus spreads across one cell every 75 minutes, fourfold faster than its replication cycle would permit. To explain this phenomenon, we found that newly infected cells express two surface proteins that mark cells as infected and, via exploitation of cellular machinery, induce the repulsion of superinfecting virions away toward uninfected cells. Mechanistically, early expression of proteins A33 and A36 was critical for virion repulsion and rapid spread, and cells expressing these proteins repelled exogenous virions rapidly. Additional spreading mechanisms may exist for other viruses that also spread faster than predicted by replication kinetics.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202693/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202693/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Doceul, Virginie -- Hollinshead, Michael -- van der Linden, Lonneke -- Smith, Geoffrey L -- 061484/Wellcome Trust/United Kingdom -- 090315/Wellcome Trust/United Kingdom -- G0501257/Medical Research Council/United Kingdom -- Medical Research Council/United Kingdom -- New York, N.Y. -- Science. 2010 Feb 12;327(5967):873-6. doi: 10.1126/science.1183173. Epub 2010 Jan 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Virology, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20093437" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Actins/metabolism ; Animals ; Cell Membrane/metabolism ; Genes, Viral ; HeLa Cells ; Humans ; Kinetics ; Membrane Glycoproteins/genetics/*metabolism ; Vaccinia virus/genetics/pathogenicity/*physiology ; Viral Envelope Proteins/genetics/*metabolism ; Viral Plaque Assay ; Viral Structural Proteins/genetics/*metabolism ; Virion/physiology ; Virus Release ; Virus Replication
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    Publikationsdatum: 2010-09-11
    Beschreibung: Proteins can sample conformational states that are critical for function but are seldom detected directly because of their low occupancies and short lifetimes. In this work, we used chemical shifts and bond-vector orientation constraints obtained from nuclear magnetic resonance relaxation dispersion spectroscopy, in concert with a chemical shift-based method for structure elucidation, to determine an atomic-resolution structure of an "invisible" folding intermediate of a small protein module: the FF domain. The structure reveals non-native elements preventing formation of the native conformation in the carboxyl-terminal part of the protein. This is consistent with the kinetics of folding in which a well-structured intermediate forms rapidly and then rearranges slowly to the native state. The approach introduces a general strategy for structure determination of low-populated and transiently formed protein states.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Korzhnev, Dmitry M -- Religa, Tomasz L -- Banachewicz, Wiktor -- Fersht, Alan R -- Kay, Lewis E -- MC_U105484373/Medical Research Council/United Kingdom -- Canadian Institutes of Health Research/Canada -- New York, N.Y. -- Science. 2010 Sep 10;329(5997):1312-6. doi: 10.1126/science.1191723.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics, the University of Toronto, Toronto, Ontario M5S 1A8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20829478" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Carrier Proteins/*chemistry ; Computational Biology ; Kinetics ; Models, Molecular ; Nuclear Magnetic Resonance, Biomolecular ; Protein Conformation ; *Protein Folding ; Protein Structure, Secondary ; *Protein Structure, Tertiary ; Software ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 50
    Publikationsdatum: 2010-10-23
    Beschreibung: Transmembrane signals initiated by a broad range of extracellular stimuli converge on nodes that regulate phospholipase C (PLC)-dependent inositol lipid hydrolysis for signal propagation. We describe how heterotrimeric guanine nucleotide-binding proteins (G proteins) activate PLC-betas and in turn are deactivated by these downstream effectors. The 2.7-angstrom structure of PLC-beta3 bound to activated Galpha(q) reveals a conserved module found within PLC-betas and other effectors optimized for rapid engagement of activated G proteins. The active site of PLC-beta3 in the complex is occluded by an intramolecular plug that is likely removed upon G protein-dependent anchoring and orientation of the lipase at membrane surfaces. A second domain of PLC-beta3 subsequently accelerates guanosine triphosphate hydrolysis by Galpha(q), causing the complex to dissociate and terminate signal propagation. Mutations within this domain dramatically delay signal termination in vitro and in vivo. Consequently, this work suggests a dynamic catch-and-release mechanism used to sharpen spatiotemporal signals mediated by diverse sensory inputs.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3046049/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3046049/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Waldo, Gary L -- Ricks, Tiffany K -- Hicks, Stephanie N -- Cheever, Matthew L -- Kawano, Takeharu -- Tsuboi, Kazuhito -- Wang, Xiaoyue -- Montell, Craig -- Kozasa, Tohru -- Sondek, John -- Harden, T Kendall -- EY010852/EY/NEI NIH HHS/ -- GM074001/GM/NIGMS NIH HHS/ -- GM38213/GM/NIGMS NIH HHS/ -- GM57391/GM/NIGMS NIH HHS/ -- GM61454/GM/NIGMS NIH HHS/ -- R01 GM057391/GM/NIGMS NIH HHS/ -- R01 GM057391-13/GM/NIGMS NIH HHS/ -- R01 GM062299/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2010 Nov 12;330(6006):974-80. doi: 10.1126/science.1193438. Epub 2010 Oct 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20966218" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amino Acid Sequence ; Animals ; Catalytic Domain ; Crystallography, X-Ray ; Enzyme Activation ; GTP-Binding Protein alpha Subunits, Gq-G11/*chemistry/*metabolism ; Guanosine Triphosphate/metabolism ; Humans ; Hydrogen Bonding ; Hydrolysis ; Isoenzymes/chemistry/metabolism ; Kinetics ; Mice ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis ; Phospholipase C beta/*chemistry/metabolism ; Protein Binding ; Protein Structure, Tertiary ; Recombinant Fusion Proteins/chemistry/metabolism ; Signal Transduction
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 51
    Publikationsdatum: 2010-05-29
    Beschreibung: Nucleosome disruption and replacement are crucial activities that maintain epigenomes, but these highly dynamic processes have been difficult to study. Here, we describe a direct method for measuring nucleosome turnover dynamics genome-wide. We found that nucleosome turnover is most rapid over active gene bodies, epigenetic regulatory elements, and replication origins in Drosophila cells. Nucleosomes turn over faster at sites for trithorax-group than polycomb-group protein binding, suggesting that nucleosome turnover differences underlie their opposing activities and challenging models for epigenetic inheritance that rely on stability of histone marks. Our results establish a general strategy for studying nucleosome dynamics and uncover nucleosome turnover differences across the genome that are likely to have functional importance for epigenome maintenance, gene regulation, and control of DNA replication.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879085/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879085/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Deal, Roger B -- Henikoff, Jorja G -- Henikoff, Steven -- 1F32GM083449/GM/NIGMS NIH HHS/ -- 1R21DA025758/DA/NIDA NIH HHS/ -- F32 GM083449-03/GM/NIGMS NIH HHS/ -- R21 DA025758/DA/NIDA NIH HHS/ -- R21 DA025758-02/DA/NIDA NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2010 May 28;328(5982):1161-4. doi: 10.1126/science.1186777.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20508129" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Alanine/analogs & derivatives/metabolism ; Animals ; Cell Line ; Drosophila Proteins/*metabolism ; Drosophila melanogaster ; *Genome, Insect ; Histones/*metabolism ; Kinetics ; Methionine/metabolism ; *Molecular Probe Techniques ; Nucleosomes/*metabolism ; Oligonucleotide Array Sequence Analysis
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 52
    Publikationsdatum: 2010-10-16
    Beschreibung: No-go decay (NGD) is one of several messenger RNA (mRNA) surveillance systems dedicated to the removal of defective mRNAs from the available pool. Two interacting factors, Dom34 and Hbs1, are genetically implicated in NGD in yeast. Using a reconstituted yeast translation system, we show that Dom34:Hbs1 interacts with the ribosome to promote subunit dissociation and peptidyl-tRNA drop-off. Our data further indicate that these recycling activities are shared by the homologous translation termination factor complex eRF1:eRF3, suggesting a common ancestral function. Because Dom34:Hbs1 activity exhibits no dependence on either peptide length or A-site codon identity, we propose that this quality-control system functions broadly to recycle ribosomes throughout the translation cycle whenever stalls occur.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4022135/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4022135/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shoemaker, Christopher J -- Eyler, Daniel E -- Green, Rachel -- R01 GM059425/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2010 Oct 15;330(6002):369-72. doi: 10.1126/science.1192430.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20947765" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Cell Cycle Proteins/genetics/*metabolism ; Codon ; Codon, Terminator ; Endoribonucleases/genetics/*metabolism ; GTP-Binding Proteins/genetics/*metabolism ; Guanosine Triphosphate/metabolism ; HSP70 Heat-Shock Proteins/genetics/*metabolism ; Kinetics ; Peptide Chain Termination, Translational ; Peptide Elongation Factors/genetics/*metabolism ; Peptide Termination Factors/metabolism ; Protein Biosynthesis ; *RNA Stability ; RNA, Fungal/genetics/*metabolism ; RNA, Messenger/genetics/*metabolism ; RNA, Transfer, Amino Acyl/genetics/*metabolism ; Recombinant Proteins/metabolism ; Ribosome Subunits/*metabolism ; Saccharomyces cerevisiae/*genetics/metabolism ; Saccharomyces cerevisiae Proteins/genetics/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 53
    Publikationsdatum: 2010-03-20
    Beschreibung: Self-replicating molecules are likely to have played an important role in the origin of life, and a small number of fully synthetic self-replicators have already been described. Yet it remains an open question which factors most effectively bias the replication toward the far-from-equilibrium distributions characterizing even simple organisms. We report here two self-replicating peptide-derived macrocycles that emerge from a small dynamic combinatorial library and compete for a common feedstock. Replication is driven by nanostructure formation, resulting from the assembly of the peptides into fibers held together by beta sheets. Which of the two replicators becomes dominant is influenced by whether the sample is shaken or stirred. These results establish that mechanical forces can act as a selection pressure in the competition between replicators and can determine the outcome of a covalent synthesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carnall, Jacqui M A -- Waudby, Christopher A -- Belenguer, Ana M -- Stuart, Marc C A -- Peyralans, Jerome J-P -- Otto, Sijbren -- New York, N.Y. -- Science. 2010 Mar 19;327(5972):1502-6. doi: 10.1126/science.1182767.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20299594" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Circular Dichroism ; Combinatorial Chemistry Techniques ; Cryoelectron Microscopy ; Evolution, Chemical ; Hydrogen-Ion Concentration ; Kinetics ; Leucine/chemistry ; Lysine/chemistry ; Macrocyclic Compounds/*chemistry ; Mechanical Phenomena ; Models, Chemical ; Molecular Conformation ; Origin of Life ; Peptide Library ; Peptides/*chemistry ; Physicochemical Processes ; Spectrum Analysis ; Stress, Mechanical ; Sulfhydryl Compounds/chemistry ; Thermodynamics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 54
    Publikationsdatum: 2010-10-30
    Beschreibung: Ribosomes are self-assembling macromolecular machines that translate DNA into proteins, and an understanding of ribosome biogenesis is central to cellular physiology. Previous studies on the Escherichia coli 30S subunit suggest that ribosome assembly occurs via multiple parallel pathways rather than through a single rate-limiting step, but little mechanistic information is known about this process. Discovery single-particle profiling (DSP), an application of time-resolved electron microscopy, was used to obtain more than 1 million snapshots of assembling 30S subunits, identify and visualize the structures of 14 assembly intermediates, and monitor the population flux of these intermediates over time. DSP results were integrated with mass spectrometry data to construct the first ribosome-assembly mechanism that incorporates binding dependencies, rate constants, and structural characterization of populated intermediates.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990404/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990404/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mulder, Anke M -- Yoshioka, Craig -- Beck, Andrea H -- Bunner, Anne E -- Milligan, Ronald A -- Potter, Clinton S -- Carragher, Bridget -- Williamson, James R -- GM-52468/GM/NIGMS NIH HHS/ -- P41 RR017573/RR/NCRR NIH HHS/ -- P41 RR017573-10/RR/NCRR NIH HHS/ -- R01 GM052468/GM/NIGMS NIH HHS/ -- R01 GM052468-16/GM/NIGMS NIH HHS/ -- R01 RR023093/RR/NCRR NIH HHS/ -- R01 RR023093-09/RR/NCRR NIH HHS/ -- R37 GM053757/GM/NIGMS NIH HHS/ -- R37 GM053757-16/GM/NIGMS NIH HHS/ -- R37-GM-53757/GM/NIGMS NIH HHS/ -- RR023093/RR/NCRR NIH HHS/ -- RR175173/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2010 Oct 29;330(6004):673-7. doi: 10.1126/science.1193220.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21030658" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Bacterial Proteins/chemistry/metabolism ; Image Processing, Computer-Assisted ; Kinetics ; Mass Spectrometry ; Microscopy, Electron/methods ; Models, Molecular ; Nucleic Acid Conformation ; Protein Binding ; Protein Conformation ; RNA, Bacterial/chemistry ; RNA, Ribosomal/chemistry ; Ribosomal Proteins/chemistry/*metabolism ; Ribosome Subunits, Small, Bacterial/chemistry/*metabolism/*ultrastructure
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 55
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2010-11-13
    Beschreibung: Cytochrome P450 enzymes are responsible for the phase I metabolism of approximately 75% of known pharmaceuticals. P450s perform this and other important biological functions through the controlled activation of C-H bonds. Here, we report the spectroscopic and kinetic characterization of the long-sought principal intermediate involved in this process, P450 compound I (P450-I), which we prepared in approximately 75% yield by reacting ferric CYP119 with m-chloroperbenzoic acid. The Mossbauer spectrum of CYP119-I is similar to that of chloroperoxidase compound I, although its electron paramagnetic resonance spectrum reflects an increase in |J|/D, the ratio of the exchange coupling to the zero-field splitting. CYP119-I hydroxylates the unactivated C-H bonds of lauric acid [D(C-H) ~ 100 kilocalories per mole], with an apparent second-order rate constant of k(app) = 1.1 x 10(7) per molar per second at 4 degrees C. Direct measurements put a lower limit of k 〉/= 210 per second on the rate constant for bound substrate oxidation, whereas analyses involving kinetic isotope effects predict a value in excess of 1400 per second.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rittle, Jonathan -- Green, Michael T -- New York, N.Y. -- Science. 2010 Nov 12;330(6006):933-7. doi: 10.1126/science.1193478.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21071661" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Biocatalysis ; Catalytic Domain ; Chlorobenzoates/chemistry ; Cytochrome P-450 Enzyme System/*chemistry/*isolation & purification/*metabolism ; Electron Spin Resonance Spectroscopy ; Fatty Acids/chemistry/metabolism ; Freezing ; Hydroxylation ; Kinetics ; Lauric Acids/chemistry/metabolism ; Ligands ; Oxidation-Reduction ; Oxygen/chemistry/metabolism ; Physicochemical Processes ; Spectroscopy, Mossbauer ; Sulfolobus acidocaldarius/enzymology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 56
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-10-12
    Beschreibung: The impermeant dye antipyrylazo III was used to measure depletion of extracellular calcium and net influx of calcium through the sarcolemma during the cardiac action potential. It was found that calcium entry occurs continuously during the action potential and is under direct control of the membrane potential. The inotropic action of epinephrine is accompanied by increased influx of calcium, while strophanthidin enhances the twitch without altering calcium influx during the action potential.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cleemann, L -- Pizarro, G -- Morad, M -- HL16152/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1984 Oct 12;226(4671):174-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6091269" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Action Potentials ; Animals ; Calcium/*metabolism ; Epinephrine/pharmacology ; Extracellular Space/*metabolism ; Ion Channels ; Kinetics ; *Myocardial Contraction/drug effects ; Myocardium/*metabolism ; Naphthalenesulfonates ; Ranidae ; Sarcolemma/*metabolism ; Spectrophotometry ; Stimulation, Chemical ; Strophanthidin/pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-11-02
    Beschreibung: New active sites can be introduced into naturally occurring enzymes by the chemical modification of specific amino acid residues with the use of appropriately designed coenzyme analogs. The resultant semisynthetic enzymes can have catalytic activities very different from those of the corresponding native enzymes. For example, papain has been converted into a highly effective oxidoreductase by covalent modification of the sulfhydryl group of the active site cysteine residue (Cys25) with flavins such as 8-bromoacetyl-10-methylisoalloxazine. Thus, it is now possible to enhance the catalytic versatility of existing enzymes through the process of "chemical mutation" of the active site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kaiser, E T -- Lawrence, D S -- New York, N.Y. -- Science. 1984 Nov 2;226(4674):505-11.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6238407" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Anaerobiosis ; *Binding Sites ; Catalysis ; Chemical Phenomena ; *Chemistry ; Chymotrypsin ; Enzymes/*chemical synthesis ; Flavins ; Kinetics ; NAD/metabolism ; Niacinamide/analogs & derivatives ; Oxidation-Reduction ; Papain ; Stereoisomerism ; Toluene/analogs & derivatives/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    Publikationsdatum: 1984-08-03
    Beschreibung: Apolipoproteins A-1 and A-2 were purified from human plasma. At concentrations present in human bile these proteins prolonged the nucleation time of cholesterol monohydrate crystals when added to model systems of supersaturated bile. In contrast, apolipoprotein C-3 and other serum proteins did not have this effect. Also, when human gallbladder bile was fractionated by gel filtration chromatography, apolipoproteins A-1 and A-2 were among the proteins present in a fraction of bile enriched in potent inhibitors of cholesterol crystal nucleation. These findings suggest that apolipoproteins A-1 and A-2 in supersaturated human gallbladder bile could inhibit the rate of formation of solid cholesterol crystals and thus help to prevent spontaneous cholesterol gallstone formation in humans.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kibe, A -- Holzbach, R T -- LaRusso, N F -- Mao, S J -- AM-17562/AM/NIADDK NIH HHS/ -- AM-24031/AM/NIADDK NIH HHS/ -- HL-32317/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1984 Aug 3;225(4661):514-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6429856" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Apolipoprotein A-I ; Apolipoprotein A-II ; Apolipoproteins/*blood ; Bile/*physiology ; Cholesterol/*metabolism ; Crystallization ; Gallbladder/physiology ; Humans ; Kinetics ; Lipoproteins, HDL/*blood ; Models, Biological
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 59
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-02-10
    Beschreibung: Ultraviolet irradiation of rat dendritic cells completely abrogated their allostimulatory capacity in a mixed lymphocyte reaction. Rat islets of Langerhans similarly irradiated remained hormonally functional when transplanted into syngeneic diabetic rats. Allogeneic transplantation across a major histocompatibility barrier of islets initially treated in vitro with ultraviolet irradiation resulted in prolonged allograft survival without the use of any immunosuppressive agents.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lau, H -- Reemtsma, K -- Hardy, M A -- New York, N.Y. -- Science. 1984 Feb 10;223(4636):607-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6420888" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Cell Survival/radiation effects ; Dose-Response Relationship, Radiation ; Islets of Langerhans/radiation effects ; *Islets of Langerhans Transplantation ; Kinetics ; Rats ; Rats, Inbred Lew ; Transplantation, Homologous ; Transplantation, Isogeneic ; *Ultraviolet Rays
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 60
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-07-13
    Beschreibung: A significant postflight reduction in the circulating red cell mass has been observed in both the American and Soviet manned programs. The mechanism and etiology of this loss were studied in blood samples from the four payload crewmen of Spacelab 1 taken before, during, and after flight. These samples and samples from control groups on the ground were analyzed for selected hematological and biochemical parameters, which were chosen on the basis of data previously collected, the restraints imposed by the use of human subjects, and the guidelines established for the first Spacelab mission. Twenty-two hours after weightless exposure, there was an increase in hemoglobin and hematocrit. On day 7 in flight, the hemoglobin and hematocrit remained high and there was a slight decrease in reticulocyte number. On landing, red cell mass, plasma volume, hematocrit, and reticulocyte number were decreased. Throughout the 2-week postflight sampling period, hemoglobin, hematocrit, and reticulocyte number remained below the preflight value. Since this crew was not exposed to 100 percent oxygen these results are viewed as evidence that other spaceflight factors cause the measured red cell mass reduction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Leach, C S -- Johnson, P C -- New York, N.Y. -- Science. 1984 Jul 13;225(4658):216-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6729477" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Erythrocyte Count ; Erythrocyte Volume ; Erythrocytes/*physiology ; Erythropoiesis ; Erythropoietin/blood ; Hematocrit ; Hemoglobins/analysis ; Humans ; Kinetics ; Reticulocytes ; *Space Flight
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 61
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-02-10
    Beschreibung: 3-Aminobenzamide and benzamide, purported to be specific inhibitors of the synthesis of poly(adenosine diphosphate-ribose), were used to elucidate possible functions of this biopolymer. These compounds, at frequently used experimental concentrations, not only inhibited the action of poly(adenosine diphosphate-ribose) synthetase but also affected cell viability, glucose metabolism, and DNA synthesis. Thus, the usefulness of 3-aminobenzamide and benzamide may be severely restricted by the difficulty of finding a dose small enough to inhibit the synthetase without producing additional metabolic effects.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Milam, K M -- Cleaver, J E -- New York, N.Y. -- Science. 1984 Feb 10;223(4636):589-91.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6420886" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Benzamides/*toxicity ; Cell Line ; DNA Replication/drug effects ; Humans ; Kinetics ; Lymphocytes ; Nucleoside Diphosphate Sugars/*biosynthesis ; Poly Adenosine Diphosphate Ribose/*biosynthesis ; Poly(ADP-ribose) Polymerases/metabolism ; Structure-Activity Relationship
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 62
    Publikationsdatum: 1984-05-11
    Beschreibung: Arabinosylcytosine, a compound that inhibits DNA synthesis in rapidly dividing cells, stimulates fetal hemoglobin in adult baboons and produces significant perturbations in the pools of erythroid progenitors. It appears that changes in the kinetics of erythroid cell differentiation rather than direct action on the gamma genes underlie stimulation of fetal hemoglobin in the adult animals in vivo. These results also suggest that chemotherapeutic agents selected for their low carcinogenic or mutagenic potential could be used for therapeutic induction of fetal hemoglobin in patients with sickle cell anemia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Papayannopoulou, T -- Torrealba de Ron, A -- Veith, R -- Knitter, G -- Stamatoyannopoulos, G -- GM 15253/GM/NIGMS NIH HHS/ -- HL-07093/HL/NHLBI NIH HHS/ -- HL-20899/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1984 May 11;224(4649):617-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6200940" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Anemia, Sickle Cell/drug therapy ; Animals ; Cell Differentiation/*drug effects ; Cytarabine/*pharmacology/therapeutic use ; Erythropoiesis/*drug effects ; Fetal Hemoglobin/*biosynthesis ; Kinetics ; Papio ; Reticulocytes/drug effects
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 63
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-11-16
    Beschreibung: The benzodiazepine-gamma-aminobutyric acid receptor complex was used to study functional receptor synthesis and degradation in primary cultures of neurons. Fifty percent of the receptors turned over with an unusually rapid half-life (4 hours); this was followed by a second, slower phase (32 hours). These results provide the basis for elucidating the mechanism by which neurons derived from the central nervous system control neurotransmitter receptor number, an important problem in cellular neurobiology. The findings may be of significance in the study of neurological and psychiatric disorders.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Borden, L A -- Czajkowski, C -- Chan, C Y -- Farb, D H -- New York, N.Y. -- Science. 1984 Nov 16;226(4676):857-60.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6093257" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Cells, Cultured ; Chick Embryo ; Flunitrazepam/metabolism ; Half-Life ; Kinetics ; Neurons/*metabolism ; Receptors, GABA-A/biosynthesis/*metabolism ; Spinal Cord/cytology ; gamma-Aminobutyric Acid/physiology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 64
    Publikationsdatum: 1984-11-23
    Beschreibung: The tachykinins are a family of peptides with the carboxyl terminal amino acid sequence Phe-X-Gly-Leu-Met-NH2. Three major mammalian tachykinins have been identified--substance K, neuromedin K, and substance P--but only two tachykinin receptors have been postulated. Three tachykinins were labeled with radioiodinated Bolton-Hunter reagent and their binding characteristics were determined in crude membrane suspensions from several tissues. In cerebral cortex labeled eledoisin exhibited high-affinity binding that was inhibited by tachykinins in a manner indicating a definitive SP-E receptor site. In gastrointestinal smooth muscle and bladder, high-affinity binding of labeled substance P was inhibited in a pattern indicating a definitive SP-P site. In intestinal smooth muscle and bladder, however, labeled substance K and labeled eledoisin were both bound in a pattern indicating a preference for substance K itself. The results suggest the existence of three distinct types of tachykinin receptors: SP-P, SP-E, and SP-K.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Buck, S H -- Burcher, E -- Shults, C W -- Lovenberg, W -- O'Donohue, T L -- New York, N.Y. -- Science. 1984 Nov 23;226(4677):987-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6095447" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Binding, Competitive ; Cell Membrane/metabolism ; Cerebral Cortex/*metabolism ; Duodenum/*metabolism ; Guinea Pigs ; Intestine, Small/*metabolism ; Kinetics ; Mice ; Organ Specificity ; Peptides/*metabolism ; Rats ; Receptors, Neurokinin-2 ; Receptors, Neurotransmitter/*metabolism ; *Receptors, Tachykinin ; Species Specificity ; Tachykinins ; Urinary Bladder/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 65
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-02-17
    Beschreibung: Neurons process and transmit information in the form of electrical signals. Their electrical excitability is due to the presence of voltage-sensitive ion channels in the neuronal plasma membrane. In recent years, the voltage-sensitive sodium channel of mammalian brain has become the first of these important neuronal components to be studied at the molecular level. This article describes the distribution of sodium channels among the functional compartments of the neuron and reviews work leading to the identification, purification, and characterization of this membrane glycoprotein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Catterall, W A -- New York, N.Y. -- Science. 1984 Feb 17;223(4637):653-61.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6320365" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Brain/metabolism ; Cell Membrane/metabolism ; Electric Organ ; Electrophorus ; Ion Channels/*metabolism ; Kinetics ; Macromolecular Substances ; Membrane Proteins/genetics/isolation & purification ; Molecular Weight ; Muscles/metabolism ; Nerve Tissue Proteins/isolation & purification ; Neurons/*metabolism/physiology ; Neurotoxins/pharmacology ; Protein Processing, Post-Translational ; Sodium/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 66
    Publikationsdatum: 1984-11-02
    Beschreibung: Cyclophilin, a specific cytosolic binding protein responsible for the concentration of the immunosuppressant cyclosporin A by lymphoid cells, was purified to homogeneity from bovine thymocytes. Cation-exchange high-performance liquid chromatography resolved a major and minor cyclophilin species that bind cyclosporin A with a dissociation constant of about 2 X 10(-7) moles per liter and specific activities of 77 and 67 micrograms per milligram of protein, respectively. Both cyclophilin species have an apparent molecular weight of 15,000, an isoelectric point of 9.6, and nearly identical amino acid compositions. A portion of the NH2-terminal amino acid sequence of the major species was determined. The cyclosporin A-binding activity of cyclophilin is sulfhydryl dependent, unstable at 56 degrees C and at pH 4 or 9.5, and sensitive to trypsin but not to chymotrypsin digestion. Cyclophilin specifically binds a series of cyclosporin analogs in proportion to their activity in a mixed lymphocyte reaction. Isolation of cyclophilin from the cytosol of thymocytes suggests that the immunosuppressive activity of cyclosporin A is mediated by an intracellular mechanism, not by a membrane-associated mechanism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Handschumacher, R E -- Harding, M W -- Rice, J -- Drugge, R J -- Speicher, D W -- New York, N.Y. -- Science. 1984 Nov 2;226(4674):544-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6238408" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amino Acid Sequence ; Animals ; Carrier Proteins/*isolation & purification/metabolism ; Cattle ; Chromatography, High Pressure Liquid ; Cyclosporins/*metabolism ; Electrophoresis, Polyacrylamide Gel ; Humans ; Isoelectric Point ; Kinetics ; Lymphocyte Culture Test, Mixed ; Mice ; Molecular Weight ; Peptidylprolyl Isomerase
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 67
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-04-20
    Beschreibung: The spatial variation of changes in intracellular calcium ions were studied with a one-dimensional scanning microphotometer. Changes in intracellular calcium were measured with a metallochromic dye, arsenazo III. Both the magnitude and the kinetics of changes in calcium were dramatically different in different regions of a cell. In Limulus ventral photoreceptors the maximum change was probably restricted to the rhabdomeric lobe.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harary, H H -- Brown, J E -- EY0914/EY/NEI NIH HHS/ -- EY0915/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1984 Apr 20;224(4646):292-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6710144" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Arsenazo III/metabolism ; Calcium/*metabolism ; Cytosol/metabolism ; Diffusion ; Horseshoe Crabs/*metabolism ; Kinetics ; Light ; Photoreceptor Cells/*metabolism ; Spectrophotometry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 68
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-02-10
    Beschreibung: Regression of the fetal rat Mullerian duct in vitro was stimulated by sodium fluoride in the absence of Mullerian inhibiting substance. The action of Mullerian inhibiting substance was inhibited by sodium vanadate, adenosine 5'-triphosphate, and several related nucleotides in the presence of manganese ions. Epidermal growth factor specifically inhibited the substance, but only with manganese ions present. Insulin, platelet-derived growth factor, and nerve growth factor had no effect. These results suggest that dephosphorylation of membrane proteins mediates the action of Mullerian inhibiting substance.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hutson, J M -- Fallat, M E -- Kamagata, S -- Donahoe, P K -- Budzik, G P -- CA-17393/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1984 Feb 10;223(4636):586-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6607531" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Anti-Mullerian Hormone ; Cations, Divalent ; Dimethyl Sulfoxide/pharmacology ; Epidermal Growth Factor/pharmacology ; Female ; *Glycoproteins ; *Growth Inhibitors ; Kinetics ; Male ; Membrane Proteins/metabolism ; Mullerian Ducts/drug effects/*physiology ; Phosphorylation ; Pregnancy ; Rats ; Sodium Fluoride/pharmacology ; Testicular Hormones/*physiology ; Vanadates ; Vanadium/pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 69
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-09-07
    Beschreibung: Several naturally occurring and synthetic flavones were found to inhibit the aromatization of androstenedione and testosterone to estrogens catalyzed by human placental and ovarian microsomes. These flavones include (in order of decreasing potency) 7,8-benzoflavone, chrysin, apigenin, flavone, flavanone, and quercetin; 5,6-benzoflavone was not inhibitory. 7,8-Benzoflavone and chrysin were potent competitive inhibitors and induced spectral changes in the aromatase cytochrome P-450 indicative of substrate displacement. Flavones may thus compete with steroids in their interaction with certain monooxygenases and thereby alter steroid hormone metabolism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kellis, J T Jr -- Vickery, L E -- AM1005/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1984 Sep 7;225(4666):1032-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6474163" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Androstenedione/*metabolism ; *Aromatase Inhibitors ; Benzoflavones/metabolism/pharmacology ; Binding Sites ; Binding, Competitive ; Female ; Flavonoids/metabolism/*pharmacology ; Humans ; Kinetics ; Microsomes/enzymology ; Ovary/*enzymology ; Oxidoreductases/*antagonists & inhibitors ; Placenta/*enzymology ; Pregnancy ; Testosterone/*metabolism ; beta-Naphthoflavone
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 70
    Publikationsdatum: 1984-05-11
    Beschreibung: Arachidonate and other unsaturated long-chain fatty acids were found to activate protein kinase C from human neutrophils. Kinase activation by arachidonate required calcium and was enhanced by diolein but did not require exogenous phosphatidylserine. Submaximal levels of arachidonate also enhanced the affinity of the kinase for calcium during activation by phosphatidylserine. Thus the release of arachidonate, which is triggered in many cell types by ligand-receptor interactions, could play a second messenger role in the regulation of cellular function by activation of protein kinase C.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McPhail, L C -- Clayton, C C -- Snyderman, R -- 5PO1CA29589/CA/NCI NIH HHS/ -- 5RO-1DEO3738/DE/NIDCR NIH HHS/ -- New York, N.Y. -- Science. 1984 May 11;224(4649):622-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6231726" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Arachidonic Acid ; Arachidonic Acids/pharmacology ; Dose-Response Relationship, Drug ; Enzyme Activation ; Fatty Acids, Unsaturated/pharmacology/*physiology ; Humans ; Kinetics ; Neutrophils/enzymology ; Phosphatidylserines/pharmacology ; Protein Kinase C ; Protein Kinases/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 71
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-11-02
    Beschreibung: By recombinant DNA techniques, a disulfide bond was introduced at a specific site in T4 lysozyme, a disulfide-free enzyme. This derivative retained full enzymatic activity and was more stable toward thermal inactivation than the wild-type protein. The derivative, T4 lysozyme (Ile3----Cys), was prepared by substituting a Cys codon for an Ile codon at position 3 in the cloned lysozyme gene by means of oligonucleotide-dependent, site-directed mutagenesis. The new gene was expressed in Escherichia coli under control of the (trp-lac) hybrid tac promoter, and the protein was purified. Mild oxidation generated a disulfide bond between the new Cys3 and Cys97, one of the two unpaired cysteines of the native molecule. Oxidized T4 lysozyme (Ile3----Cys) exhibited specific activity identical to that of the wild-type enzyme when measured at 20 degrees C in a cell-clearing assay. The cross-linked protein was more stable than the wild type during incubation at elevated temperatures as determined by recovered enzymatic activity at 20 degrees C.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Perry, L J -- Wetzel, R -- New York, N.Y. -- Science. 1984 Nov 2;226(4674):555-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6387910" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Chemical Phenomena ; Chemistry ; DNA, Recombinant/metabolism ; Escherichia coli/enzymology ; *Genetic Engineering ; Kinetics ; Muramidase/*genetics/metabolism ; Protein Denaturation
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 72
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-04-20
    Beschreibung: Human epidermoid carcinoma A431 cells in culture produce a soluble 105-kilodalton protein which, by the criteria of epidermal growth factor (EGF) binding, recognition by monoclonal and polyclonal antibodies to the EGF receptor, amino-terminal sequence analysis and carbohydrate content, is related to the cell surface domain of the EGF receptor. The high rate of production and the finding that with biosynthetic labeling the specific activity of this 105-kilodalton protein exceeds that of the intact receptor indicate that it is not derived from membrane-bound mature receptor but is separately produced by the cell. These cells thus separately synthesize an EGF receptor that is inserted into the membrane and an EGF receptor-related protein that is secreted.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weber, W -- Gill, G N -- Spiess, J -- AM13149/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1984 Apr 20;224(4646):294-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6324343" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amino Acid Sequence ; Antibodies, Monoclonal/immunology ; Carbohydrates/analysis ; Carcinoma, Squamous Cell/*metabolism ; Cell Line ; Epidermal Growth Factor/metabolism ; Glycoproteins/analysis/*biosynthesis ; Humans ; Kinetics ; Molecular Weight ; Receptor, Epidermal Growth Factor ; Receptors, Cell Surface/analysis/immunology/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 73
    Publikationsdatum: 1984-11-23
    Beschreibung: Metastatic mouse melanoma cells have a high affinity for the basement membrane and the ability to degrade it; these properties may allow tumor cells to invade the membrane and disseminate. In this study it was found that the metastatic potential of mouse melanoma cells varied when the cells were exposed in culture to fibronectin or laminin. After removal of fibronectin or exposure to laminin, the cells had an increased affinity for basement membrane collagen, were more invasive of basement membranes in vitro, and produced more lung colonies in vivo. These changes are correlated with and may be due to an increase in the laminin-binding capacity of the tumor cell surface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Terranova, V P -- Williams, J E -- Liotta, L A -- Martin, G R -- New York, N.Y. -- Science. 1984 Nov 23;226(4677):982-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6505678" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Amnion/physiology ; Animals ; Cell Division/drug effects ; Cell Line ; Female ; Fibronectins/*pharmacology ; Humans ; Immune Sera ; Kinetics ; Laminin/*pharmacology ; Melanoma/*pathology ; Mice ; Neoplasm Metastasis/*pathology ; Pregnancy
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 74
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-02-10
    Beschreibung: The resistance of the infectious agent of scrapie disease to sterilization at 100 degrees or 121 degrees C is reputed to be inconsistent with the structure of conventional viruses. However, in kinetic studies the majority of hamster scrapie strain 263K infectivity was (like that of previously characterized viruses) rapidly inactivated at temperatures of 100 degrees C or greater. Small resistant subpopulations remained. Similar heat-resistant subpopulations were observed at 60 degrees C for phage lambda but only in the presence of brain homogenate. Brain homogenate may also confer stability to small subfractions of scrapie infectivity. Such refractory subpopulations cannot be used to make structural inferences that are properly obtained from the behavior of the majority population as revealed in the initial inactivation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rohwer, R G -- New York, N.Y. -- Science. 1984 Feb 10;223(4636):600-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6420887" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Brain/microbiology ; Cricetinae ; *Hot Temperature ; Kinetics ; Prions/*growth & development ; Species Specificity ; Sterilization/methods
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 75
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1984-03-16
    Beschreibung: 5-Amino-4-imidazolecarboxamide riboside triphosphate (ZTP) is thought to play a regulatory role in cellular metabolism. Unlike other nucleoside triphosphates, ZTP is synthesized in a one-step reaction in which the pyrophosphate group of 5-phosphoribosyl-l-pyrophosphate is transferred to the riboside monophosphate (ZMP) in a reaction catalyzed by 5-phosphoribosyl-l-pyrophosphate synthetase; reversal of this reaction leads to dephosphorylation of ZTP to ZMP. This unusual route of synthesis (and catabolism) of ZTP may be important in defining its metabolic effects in the cell.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sabina, R L -- Holmes, E W -- Becker, M A -- AM12413/AM/NIADDK NIH HHS/ -- AM28554/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1984 Mar 16;223(4641):1193-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6199843" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphate/metabolism ; Aminoimidazole Carboxamide/analogs & derivatives/*biosynthesis/pharmacology ; Animals ; Cell Line ; Cricetinae ; Imidazoles/*biosynthesis ; Kinetics ; Phosphoribosyl Pyrophosphate/metabolism ; Phosphorylation ; Ribonucleosides/pharmacology ; Ribonucleotides/*biosynthesis ; Ribose-Phosphate Pyrophosphokinase/metabolism ; Substrate Specificity
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 76
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-12-16
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 1983 Dec 16;222(4629):1251-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6648532" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Behavior, Animal/drug effects ; Flupenthixol/*pharmacology ; Hypothalamus/*drug effects ; Kinetics ; Rats ; *Reward ; Self Stimulation/*drug effects ; Thioxanthenes/*pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 77
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-25
    Beschreibung: Microinfusions of rat prolactin into the dorsal midbrain of estrogen-treated, ovariectomized rats increased lordosis behavior. Midbrain microinfusions of antiserum to prolactin into rats displaying maximum lordosis had the opposite effect. The distribution of a prolactin-like substance in the brain was studied immunocytochemically. The results suggest that a hypothalamic neuronal system projecting to the midbrain contains a prolactin-like substance that plays a role in facilitating this behavior and therefore may mediate some of the effects of estrogen on the brain. These data, together with others from studies of the prolactin gene and its regulation, indicate that it may be possible to analyze a sequence of molecular events in the brain that facilitate a behavioral response.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harlan, R E -- Shivers, B D -- Pfaff, D W -- HD-05585/HD/NICHD NIH HHS/ -- HD-05737/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1983 Mar 25;219(4591):1451-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6828874" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adrenalectomy ; Animals ; Castration ; Cerebral Cortex/drug effects/*physiology ; Cosyntropin/pharmacology ; Estradiol/pharmacology ; Female ; Growth Hormone/pharmacology ; Immune Sera ; Kinetics ; Mesencephalon/*physiology ; Oxytocin/pharmacology ; Posture ; Prolactin/administration & dosage/*pharmacology ; Rats ; Sexual Behavior, Animal/*drug effects ; Vasopressins/pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 78
    Publikationsdatum: 1983-12-23
    Beschreibung: Endotoxin-free thymosin fraction 5 elevated corticotropin, beta-endorphin, and cortisol in a dose- and time-dependent fashion when administered intravenously to prepubertal cynomolgus monkeys. Two synthetic component peptides of thymosin fraction 5 had no acute effects on pituitary function, suggesting that some other peptides in thymosin fraction 5 were responsible for its corticotropin-releasing activity. In agreement with these observations, total thymectomy of juvenile macaques was associated with decreases in plasma cortisol, corticotropin, and beta-endorphin. These findings indicate that the prepubertal primate thymus contains corticotropin-releasing activity that may contribute to a physiological immunoregulatory circuit between the developing immunological and pituitary-adrenal systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Healy, D L -- Hodgen, G D -- Schulte, H M -- Chrousos, G P -- Loriaux, D L -- Hall, N R -- Goldstein, A L -- CA 24974/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1983 Dec 23;222(4630):1353-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6318312" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adrenocorticotropic Hormone/*blood ; Animals ; Dose-Response Relationship, Drug ; Endorphins/blood ; Female ; Hydrocortisone/blood ; Kinetics ; Macaca fascicularis ; Thymectomy ; Thymosin/analogs & derivatives/*pharmacology ; Thymus Gland/*physiology ; beta-Endorphin
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 79
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-04
    Beschreibung: Efforts in estimating carcinogenic risk in humans from long-term exposure to chemical carcinogens have centered on the problem of low-dose extrapolation. For chemicals with metabolites that interact with DNA, it may be more meaningful to relate tumor response to the concentration of the DNA adducts in the target organ rather than to the applied dose. Many data suggest that the relation between tumor response and concentration of DNA adducts in the target organ may be linear. This implies that the nonlinearities of the dose-response curve for tumor induction may be due to the kinetic processes involved in the formation of carcinogen metabolite--DNA adducts. Of particular importance is the possibility that the kinetic processes may show a nonlinear "hockey-stick" like behavior which results from saturation of detoxification or DNA repair processes. The mathematical models typically used for low-dose extrapolation are shown potentially to overestimate risk by several orders of magnitude when nonlinear kinetics are present.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hoel, D G -- Kaplan, N L -- Anderson, M W -- New York, N.Y. -- Science. 1983 Mar 4;219(4588):1032-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6823565" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Carcinogens/*administration & dosage ; Cell Transformation, Neoplastic/*drug effects ; DNA, Neoplasm/genetics ; Dose-Response Relationship, Drug ; Humans ; Kinetics ; Models, Biological ; Neoplasms/*chemically induced ; Risk
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 80
    Publikationsdatum: 1983-11-25
    Beschreibung: Analysis of the polarized single-crystal absorption spectra of cytochrome cd1 of Pseudomonas aeruginosa shows that the heme c and heme d1 groups in each subunit are oriented perpendicularly to each other in both oxidized and reduced forms of the enzyme. These results, together with those of previous kinetic studies, indicate that a perpendicular heme-heme orientation may be an important factor in specifying kinetically slow steps in a sequential series of electron transfer reactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Makinen, M W -- Schichman, S A -- Hill, S C -- Gray, H B -- 1-T32-HD-07009/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1983 Nov 25;222(4626):929-31.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6415814" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): *Cytochromes ; *Electron Transport ; *Heme ; Kinetics ; *Nitrite Reductases ; Pseudomonas aeruginosa/enzymology ; Spectrum Analysis
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 81
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-12-09
    Beschreibung: Measurements of vapor pressures over their aqueous solutions indicate that organic compounds show profound differences in hydrophilic character. These differences are of such magnitude as to suggest an important role for changing solvation in determining free energy changes associated with metabolic transformations in water, and in governing structural equilibria of proteins and other large molecules in water. When two or more functional groups are present within the same solute molecule, their combined effects on its free energy of solvation are commonly additive. Striking departures from additivity, observed in certain cases, indicate the existence of special interactions between different parts of a solute molecule and the water that surrounds it. Similar considerations presumably apply to activated intermediates in the interconversion of biological materials.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wolfenden, R -- GM 18325/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1983 Dec 9;222(4628):1087-93.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6359416" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Chemistry, Organic ; Enzymes/physiology ; Kinetics ; Metabolism ; Nucleic Acid Conformation ; Nucleic Acids/physiology ; Organic Chemistry Phenomena ; Protein Conformation ; Solvents ; Water/*physiology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 82
    Publikationsdatum: 1983-10-28
    Beschreibung: Fluorinated anesthetics were observed noninvasively in the brain of intact rabbits with fluorine-19 nuclear magnetic resonance spectroscopy. High-resolution fluorine-19 spectra of halothane, methoxyflurane, and isoflurane were obtained with a surface coil centered over the calvarium. Elimination of halothane from the brain was also monitored by this technique. Residual fluorine-19 signals from halothane (or a metabolite) could be detected as long as 98 hours after termination of anesthesia. These observations demonstrate the feasibility of using this technique to study the fate of fluorinated anesthetics in live mammals.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wyrwicz, A M -- Pszenny, M H -- Schofield, J C -- Tillman, P C -- Gordon, R E -- Martin, P A -- GM 29520/GM/NIGMS NIH HHS/ -- K04 GM 00503/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1983 Oct 28;222(4622):428-30.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6623084" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Brain/*metabolism ; Halothane/*metabolism ; Isoflurane/*metabolism ; Kinetics ; Magnetic Resonance Spectroscopy ; Methoxyflurane/*metabolism ; Methyl Ethers/*metabolism ; Rabbits
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 83
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-10-07
    Beschreibung: Acetylcholine receptors at innervated neuromuscular junctions are very stable, with half-lives reported to be 6 to 13 days. Their turnover is described as a first-order process, implying a single population of receptors. In this study, two subpopulations of acetylcholine receptors at normally innervated junctions have been identified. One has a rapid turnover rate with a half-life of 18.7 hours, similar to that of extrajunctional receptors, and the other has a slow turnover rate with a half-life of 12.4 days. The rapidly turned over subpopulation represents approximately 20 percent of the total junctional receptors. This finding may account for the discrepancies in previous reports of turnover rates and may explain the rapid reversibility in vivo of agents that "irreversibly" block acetylcholine receptors. This finding also implies that the synthesis rate of junctional acetylcholine receptors may be higher than previous estimates. The rapidly turned-over subpopulation may represent receptors that were newly inserted into the neuromuscular junction and that were not yet stabilized by an influence of the motor nerve.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stanley, E F -- Drachman, D B -- 5 P01 NS10920/NS/NINDS NIH HHS/ -- 5 R01 HD04817/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1983 Oct 7;222(4619):67-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6623057" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Bungarotoxins ; Diaphragm ; Kinetics ; Mice ; Neuromuscular Junction/*metabolism ; Receptors, Cholinergic/biosynthesis/classification/*metabolism ; Synaptic Membranes/metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-25
    Beschreibung: Tension transients were recorded in a single smooth muscle cell. The transient contains a linear elastic response and a biphasic recovery that appear to originate from the cross-bridges. A comparison of transients in smooth and fast skeletal muscle fibers suggests that the cross-bridge in smooth muscle is more compliant than the cross-bridge in striated muscle and that transitions between several cross-bridge states occur more slowly in smooth muscle than in striated muscle.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Warshaw, D M -- Fay, F S -- HL 05770/HL/NHLBI NIH HHS/ -- HL 14523/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1983 Mar 25;219(4591):1438-41.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6828870" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; In Vitro Techniques ; Kinetics ; *Muscle Contraction ; Muscle Relaxation ; Muscle, Smooth/*physiology ; Muscles/physiology ; Stress, Mechanical
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 85
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-18
    Beschreibung: Several lines of evidence suggest that there might be immunologic cross-reactivity between the thyroid plasma membrane in humans and antigenic determinants in the enteric pathogen Yersinia enterocolitica. Studies were therefore performed to determine whether Y. enterocolitica, like the thyroid membrane, contains a thyrotropin binding site. A saturable binding site for bovine thyrotropin was indeed demonstrable, particularly in preparations of the organism that have been treated with ethylenediaminetetraacetate and lysozyme. Hormonal specificity of the binding site, as judged from the inhibition of binding of 125I-labeled bovine thyrotropin, was similar to that of the thyrotropin receptor in human thyroid tissue.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weiss, M -- Ingbar, S H -- Winblad, S -- Kasper, D L -- AM 18416/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1983 Mar 18;219(4590):1331-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6298936" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Binding Sites ; Binding, Competitive ; Kinetics ; Receptors, Cell Surface/*metabolism ; Receptors, Thyrotropin ; Thyrotropin/*metabolism ; Yersinia enterocolitica/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 86
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-25
    Beschreibung: Anchorage-dependent cell growth is demonstrated on microcarriers of fluorocarbon fluid formed by emulsification and stabilized with polylysine.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keese, C R -- Giaever, I -- New York, N.Y. -- Science. 1983 Mar 25;219(4591):1448-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6828872" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Cell Adhesion ; Cell Division ; *Cell Physiological Phenomena ; Cells, Cultured ; Culture Media ; Emulsions ; Fluorocarbons ; Kinetics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 87
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-08-19
    Beschreibung: Metal-ion affinity (formation) constants were determined for two "Good's" buffers, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES) and N,N-bis(2-hydroxyethyl)glycine (bicine). The metal chelates formed undergo loss of an internal ligand (alcohol) proton (bicine) and undergo hydrolysis (bicine and TES) and dimerization reactions (TES). Bicine and TES buffer not only hydrogen ions but also metal ions. The metal complexes of "Good's" buffers also buffer hydrogen ions by secondary reactions. The consequences of these reactions are considered in relation to biomedical research.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nakon, R -- Krishnamoorthy, C R -- New York, N.Y. -- Science. 1983 Aug 19;221(4612):749-50.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6879173" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Apoenzymes ; *Buffers ; *Chelating Agents ; Glycine/analogs & derivatives ; Kinetics ; Metalloproteins ; Metals ; Tromethamine/analogs & derivatives
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 88
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-25
    Beschreibung: The human pathogen Trypanosoma cruzi (Y strain) contains a neuraminidase activity that varies widely in the different developmental stages of the parasite. The specific neuraminidase activity of infective trypomastigotes obtained from tissue culture and from the bloodstream of infected mice is 7 to 15 times higher than that of the acellular culture forms. Amastigotes were devoid of enzyme activity. The enzyme has a pH optimum of 6.0 to 6.5. Live trypanosomes released sialic acid from human erythrocytes and plasma glycoproteins. Several sialyl compounds were hydrolyzed by the parasite, but the best substrate was the protein orosomucoid. Erythrocytes from infected mice with T. cruzi parasitemia were agglutinated by peanut lectin and the hemagglutination titer was correlated with the degree of parasitemia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pereira, M E -- IRO1-AI-18102-01/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1983 Mar 25;219(4591):1444-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6338592" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Aging ; Animals ; Kinetics ; Neuraminidase/*metabolism ; Substrate Specificity ; Trypanosoma cruzi/enzymology/*growth & development
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 89
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-25
    Beschreibung: Cultured tobacco plant cells activated 2-aminofluorene to an agent mutagenic to Salmonella typhimurium strain TA98. The plant activation of 2-aminofluorene is heat-inactivated and may not involve solely cytochrome P-450. The kinetics of activation demonstrated both time- and concentration-dependent responses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Plewa, M J -- Weaver, D L -- Blair, L C -- Gentile, J M -- ES02384/ES/NIEHS NIH HHS/ -- New York, N.Y. -- Science. 1983 Mar 25;219(4591):1427-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6338591" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Biotransformation ; Cells, Cultured ; Fluorenes/*metabolism/pharmacology ; Kinetics ; Mutagenicity Tests ; Mutagens/*metabolism ; *Mutation ; *Plants, Toxic ; Salmonella typhimurium/drug effects ; Tobacco/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 90
    Publikationsdatum: 1983-06-10
    Beschreibung: An attempt was made to determine whether phosphorylation of the myosin light chain represents a thick filament-associated mechanism for modulating the rate of cross-bridge cycling in mouse skeletal muscle. When the degree of light chain phosphorylation was varied independently of tetanus duration, there was no correlation of phosphorylation with cross-bridge turnover rate, as measured by the shortening velocity of the muscle. It is concluded that in intact skeletal muscle phosphorylation of the myosin light chain does not in itself modulate cross-bridge cycling rate and that previously reported changes in cycling rate were due to other factors that may vary with tetanus duration.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Butler, T M -- Siegman, M J -- Mooers, S U -- Barsotti, R J -- AM 00973/AM/NIADDK NIH HHS/ -- HL 15835/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1983 Jun 10;220(4602):1167-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6857239" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Kinetics ; Mice ; Muscle Contraction ; Muscles/*metabolism/physiology ; Myosins/*metabolism/physiology ; Phosphorylation ; Rats
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 91
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-10-21
    Beschreibung: Male and female rats exhibit sex differences in binding by serotonin 1 receptors in discrete areas of the brain, some of which have been implicated in the control of ovulation and of gonadotropin release. The sex-specific changes in binding, which occur in response to the same hormonal (estrogenic) stimulus, are due to changes in the number of binding sites. Castration alone also affects the number of binding sites in certain areas. The results lead to the conclusion that peripheral hormones modulate binding by serotonin 1 receptors. The status of the serotonin receptor system may affect the reproductive capacity of an organism and may be related to sex-linked emotional disturbances in humans.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fischette, C T -- Biegon, A -- McEwen, B S -- AM06122/AM/NIADDK NIH HHS/ -- NS06080/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1983 Oct 21;222(4621):333-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6623080" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Brain/*metabolism ; Brain Mapping ; Castration ; Cell-Free System ; Estradiol/*pharmacology ; Female ; Glucosephosphate Dehydrogenase/metabolism ; Kinetics ; Male ; Pituitary Gland/enzymology ; Rats ; Receptors, Serotonin/drug effects/*metabolism ; *Sex Factors
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 92
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-03-25
    Beschreibung: The carcinogen aflatoxin B1 was reacted with a polymer of alternating deoxyguanine and deoxycytosine residues to determine the effect that adduct formation has on the conversion of this polymer from the right-handed B-DNA form found at low salt concentrations to the left-handed Z-DNA form found at high salt concentrations. Reaction with aflatoxin strongly inhibited the salt-induced conversion of this polymer from B-DNA to Z-DNA. This inhibition could be detected even at relatively low binding levels.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nordheim, A -- Hao, W M -- Wogan, G N -- Rich, A -- New York, N.Y. -- Science. 1983 Mar 25;219(4591):1434-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6402818" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Aflatoxin B1 ; Aflatoxins/*pharmacology ; Circular Dichroism ; DNA/*metabolism ; Kinetics ; Nucleic Acid Conformation ; Osmolar Concentration ; Sodium Chloride/pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 93
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1983-08-12
    Beschreibung: The polyamine metabolism of transplanted N-nitrosomethylurea-derived rat glioma was determined with radiolabeled putrescine used as a marker for malignancy. The uptake of putrescine in vivo was complete within 5 minutes and was specific for tumor tissue. The conversion of putrescine to spermine and other metabolites by the tumor was rapid, in contrast to the case for adjacent normal brain. These results suggest that putrescine labeled with carbon-11 may be used as a positron-emission tomographic tracer for the selective metabolic imaging of brain tumor and may be used in an appropriate model as a marker for tumor growth rate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Volkow, N -- Goldman, S S -- Flamm, E S -- Cravioto, H -- Wolf, A P -- Brodie, J D -- NS15638/NS/NINDS NIH HHS/ -- S07RR05399/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1983 Aug 12;221(4611):673-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6603020" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Autoradiography ; Brain Neoplasms/*radionuclide imaging ; Glioma/radionuclide imaging ; Kinetics ; Neoplasm Transplantation ; *Putrescine/metabolism ; Rats ; Tomography, Emission-Computed
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 94
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-07-16
    Beschreibung: A method has been developed for the measurement of intracellular free calcium in mammalian cells. The calcium-sensitive photoprotein aequorin can be incorporated into isolated cells by hypo-osmotic treatment without altering the cell viability, permeability, or metabolism. Intracellular calcium activity (Cai2+) was monitored in a perfusion system. In monkey kidney cells (LLC-MK2), Cai2+ is approximately 57 nanomoles per liter. Changes in Cai2+ with time can also be followed: exposure of the cells to anaerobiosis or the calcium ionophore A23187 reversibly increases Cai2+. The method has also been successfully tested in rat hepatocytes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Borle, A B -- Snowdowne, K W -- New York, N.Y. -- Science. 1982 Jul 16;217(4556):252-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6806904" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): *Aequorin ; Anaerobiosis ; Animals ; Calcimycin/pharmacology ; Calcium/*metabolism ; Cell Line ; Kidney/drug effects/*metabolism ; Kinetics ; *Luminescent Proteins ; Macaca mulatta
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 95
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-06-11
    Beschreibung: Receptors that selectively bind micromolar concentrations of benzodiazepines are present in rat brain membrane. These micromolar receptors exhibit saturable, stereospecific binding, and the potency of benzodiazepine binding to these receptors is correlated with the ability of the benzodiazepines to inhibit maximum electric shock-induced convulsions. Benzodiazepine receptors with nanomolar affinity differ from the micromolar receptors in their binding, kinetic, and pharmacologic characteristics. The micromolar receptors also bind phenytoin, a non-benzodiazepine anticonvulsant. These results provide evidence for a distinct class of clinically relevant benzodiazepine receptors that may regulate neuronal excitability and anticonvulsant activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bowling, A C -- DeLorenzo, R J -- NS 1352/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1982 Jun 11;216(4551):1247-50.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6281893" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Benzodiazepines/*metabolism/pharmacology ; Benzodiazepinones/metabolism ; Brain/*metabolism ; Calmodulin/antagonists & inhibitors ; Diazepam/metabolism ; Kinetics ; Ligands ; Protein Kinase Inhibitors ; Rats ; Receptors, Drug/*metabolism ; Receptors, GABA-A ; Structure-Activity Relationship
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 96
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-11-05
    Beschreibung: Simple chemical catalysts have been designed to achieve some desirable features of enzymes. These novel catalysts are not proteins, but they may incorporate the typical enzyme catalytic groups and they achieve selectivity in their reactions by use of geometric control, as do enzymes. Catalysts that carry out geometrically controlled chlorinations of aromatic rings and steroids have been constructed. Other catalysts achieve the selective synthesis of amino acids, and still others imitate ribonuclease in detailed mechanism and hydrolyze RNA. Optimization of geometries has led to a rate acceleration of over 10(8) in one instance.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Breslow, R -- New York, N.Y. -- Science. 1982 Nov 5;218(4572):532-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7123255" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Catalysis ; Cyclodextrins ; *Enzymes ; Kinetics ; Models, Chemical ; Ribonucleases ; Structure-Activity Relationship ; Substrate Specificity ; Transaminases
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-03-12
    Beschreibung: Brief tetanic stimulation of the preganglionic nerves to the superior cervical ganglion enhances the postganglionic response to single preganglionic stimuli for 1 to 3 hours. This long-term potentiation of transmission through the ganglion is apparently not attributable to a persistent muscarinic action of the preganglionic neurotransmitter, acetylcholine, since neither the magnitude nor the time course of the phenomenon is reduced by atropine. The decay of long-term potentiation can be described by a first-order kinetic process with a mean time constant of 80 minutes. We conclude that long-term potentiation, once considered a unique property of the hippocampus, is in fact a more general feature of synaptic function. This form of synaptic memory may significantly influence information processing and control in other regions of the nervous system, including autonomic ganglia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brown, T H -- McAfee, D A -- 12116/PHS HHS/ -- NS 16576/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1982 Mar 12;215(4538):1411-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6278593" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Ganglia, Sympathetic/*physiology ; Kinetics ; Learning/*physiology ; Neuronal Plasticity ; Rats ; Synapses/*physiology ; *Synaptic Transmission ; Time Factors
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 98
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-10-01
    Beschreibung: Studies of isolated islets labeled with radioactive leucine show that glucose at a critical time "marks" islets in such a way as to cause preferential release of newly synthesized insulin. The preferential release of insulin from marked islets is relatively independent of subsequent secretagogues or rates of insulin secretion. Previous kinetic studies have indicated that the critical time at which marking occurs is after proinsulin biosynthesis but before the secretory event. Thus, secretory cells may regulate the diversion of newly synthesized material for immediate release as it is approaching or transiting the Golgi apparatus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gold, G -- Gishizky, M L -- Grodsky, G M -- AM 01410/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1982 Oct 1;218(4567):56-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6181562" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): 1-Methyl-3-isobutylxanthine/pharmacology ; Animals ; Glucose/*pharmacology ; In Vitro Techniques ; Insulin/biosynthesis/*secretion ; Islets of Langerhans/drug effects/*secretion ; Kinetics ; Leucine ; Potassium/pharmacology ; Tolbutamide/pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-10-01
    Beschreibung: Rats rotated to the left when 5'-N-ethylcarboxamide adenosine (NECA) was injected into the left caudate nucleus and apomorphine was administered subcutaneously. The combination of NECA and apomorphine was more potent than L-(phenylisopropyl)adenosine and apomorphine in eliciting rotation, suggesting the involvement of adenosine receptors of the Ra type. The response was reduced when 2',5'-dideoxyadenosine was injected along with NECA into the caudate nucleus or when theorphylline was given intraperitoneally. Higher doses of apomorphine elicited a self-mutilatory response after the injection of NECA into the caudate nucleus. These results suggest that adenosine may be involved in the modulation of dopaminergic function in the striatum.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Green, R D -- Proudfit, H K -- Yeung, S M -- New York, N.Y. -- Science. 1982 Oct 1;218(4567):58-61.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7123218" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine/administration & dosage/*analogs & derivatives/pharmacology ; Adenosine-5'-(N-ethylcarboxamide) ; Animals ; Apomorphine/pharmacology ; Caudate Nucleus/*physiology ; Corpus Striatum/*physiology ; Dopamine/*physiology ; Injections ; Kinetics ; Male ; Motor Activity/drug effects ; Rats ; Rats, Inbred Strains ; Rotation ; Vasodilator Agents/*pharmacology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1982-01-01
    Beschreibung: Administration of the hepatic carcinogen aflatoxin B1 to experimental animals results in covalent binding to liver mitochondrial DNA at concentrations three to four times higher than nuclear DNA. The concentration of carcinogen adducts in mitochondrial DNA remains unchanged even after 24 hours, possible because of lack of excision repair. Similarly, mitochondrial transcription and translation remain inhibited up to 24 hours suggesting long-term effects of aflatoxin B1 on the mitochondrial genetic system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Niranjan, B G -- Bhat, N K -- Avadhani, N G -- CA-22762/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1982 Jan 1;215(4528):73-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6797067" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Aflatoxin B1 ; Aflatoxins/*metabolism ; Animals ; DNA, Mitochondrial/*metabolism ; Kinetics ; Liver Neoplasms/*chemically induced/metabolism ; Male ; Mitochondria, Liver/*metabolism ; Neoplasms, Experimental/chemically induced ; Protein Biosynthesis/drug effects ; Rats ; Transcription, Genetic/drug effects
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...