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  • Models, Biological  (427)
  • American Association for the Advancement of Science (AAAS)  (308)
  • Nature Publishing Group (NPG)  (119)
  • American Association for the Advancement of Science
  • Irkutsk : Ross. Akad. Nauk, Sibirskoe Otd., Inst. Zemnoj Kory
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • 2005-2009  (391)
  • 1985-1989  (36)
Collection
Publisher
  • American Association for the Advancement of Science (AAAS)  (308)
  • Nature Publishing Group (NPG)  (119)
  • American Association for the Advancement of Science
  • Irkutsk : Ross. Akad. Nauk, Sibirskoe Otd., Inst. Zemnoj Kory
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
Years
Year
  • 1
    Publication Date: 2009-12-23
    Description: Reprogramming of somatic cell nuclei to yield induced pluripotent stem (iPS) cells makes possible derivation of patient-specific stem cells for regenerative medicine. However, iPS cell generation is asynchronous and slow (2-3 weeks), the frequency is low (〈0.1%), and DNA demethylation constitutes a bottleneck. To determine regulatory mechanisms involved in reprogramming, we generated interspecies heterokaryons (fused mouse embryonic stem (ES) cells and human fibroblasts) that induce reprogramming synchronously, frequently and fast. Here we show that reprogramming towards pluripotency in single heterokaryons is initiated without cell division or DNA replication, rapidly (1 day) and efficiently (70%). Short interfering RNA (siRNA)-mediated knockdown showed that activation-induced cytidine deaminase (AID, also known as AICDA) is required for promoter demethylation and induction of OCT4 (also known as POU5F1) and NANOG gene expression. AID protein bound silent methylated OCT4 and NANOG promoters in fibroblasts, but not active demethylated promoters in ES cells. These data provide new evidence that mammalian AID is required for active DNA demethylation and initiation of nuclear reprogramming towards pluripotency in human somatic cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906123/" 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/PMC2906123/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bhutani, Nidhi -- Brady, Jennifer J -- Damian, Mara -- Sacco, Alessandra -- Corbel, Stephane Y -- Blau, Helen M -- AG009521/AG/NIA NIH HHS/ -- AG024987/AG/NIA NIH HHS/ -- AI007328/AI/NIAID NIH HHS/ -- R01 AG009521/AG/NIA NIH HHS/ -- R01 AG009521-25/AG/NIA NIH HHS/ -- R01 AG024987/AG/NIA NIH HHS/ -- R01 AG024987-05/AG/NIA NIH HHS/ -- T32 AI007328/AI/NIAID NIH HHS/ -- U01 HL100397/HL/NHLBI NIH HHS/ -- England -- Nature. 2010 Feb 25;463(7284):1042-7. doi: 10.1038/nature08752.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Baxter Laboratory for Stem Cell Biology, Institute for Stem Cell Biology and Regenerative Medicine, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5175, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20027182" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Division ; Cell Fusion ; Cell Line ; Cells, Cultured ; Cellular Reprogramming/genetics/*physiology ; Chromatin Immunoprecipitation ; Cytidine Deaminase/deficiency/genetics/*metabolism ; DNA/chemistry/genetics/metabolism ; *DNA Methylation ; DNA Replication ; Embryonic Stem Cells/cytology/metabolism ; Fibroblasts/cytology/metabolism ; Gene Expression Regulation ; Gene Knockdown Techniques ; Homeodomain Proteins/genetics ; Humans ; Induced Pluripotent Stem Cells/*cytology/enzymology/*metabolism ; Lung/cytology/embryology ; Mice ; Models, Biological ; Octamer Transcription Factor-3/genetics ; Promoter Regions, Genetic/genetics ; Time Factors
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
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  • 2
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    Nature Publishing Group (NPG)
    Publication Date: 2009-06-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reiff, Sarah B -- Striepen, Boris -- England -- Nature. 2009 Jun 18;459(7249):918-9. doi: 10.1038/459918a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19536248" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Humans ; Malaria, Falciparum/drug therapy/*parasitology ; Models, Biological ; Plasmodium falciparum/*metabolism ; Protein Binding ; Protein Transport ; Protozoan Proteins/antagonists & inhibitors/*metabolism ; Vacuoles/metabolism/parasitology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2009-12-18
    Description: An important challenge in systems biology is to quantitatively describe microbial growth using a few measurable parameters that capture the essence of this complex phenomenon. Two key events at the cell membrane-extracellular glucose sensing and uptake-initiate the budding yeast's growth on glucose. However, conventional growth models focus almost exclusively on glucose uptake. Here we present results from growth-rate experiments that cannot be explained by focusing on glucose uptake alone. By imposing a glucose uptake rate independent of the sensed extracellular glucose level, we show that despite increasing both the sensed glucose concentration and uptake rate, the cell's growth rate can decrease or even approach zero. We resolve this puzzle by showing that the interaction between glucose perception and import, not their individual actions, determines the central features of growth, and characterize this interaction using a quantitative model. Disrupting this interaction by knocking out two key glucose sensors significantly changes the cell's growth rate, yet uptake rates are unchanged. This is due to a decrease in burden that glucose perception places on the cells. Our work shows that glucose perception and import are separate and pivotal modules of yeast growth, the interaction of which can be precisely tuned and measured.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2796206/" 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/PMC2796206/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Youk, Hyun -- van Oudenaarden, Alexander -- DP1 OD003936/OD/NIH HHS/ -- DP1 OD003936-01/OD/NIH HHS/ -- DP1 OD003936-02/OD/NIH HHS/ -- R01 GM068957/GM/NIGMS NIH HHS/ -- R01 GM068957-06/GM/NIGMS NIH HHS/ -- R01 GM068957-07/GM/NIGMS NIH HHS/ -- England -- Nature. 2009 Dec 17;462(7275):875-9. doi: 10.1038/nature08653.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016593" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Transport/drug effects ; Cell Growth Processes/drug effects ; Cell Membrane/drug effects/metabolism ; Doxycycline/pharmacology ; Glucose/*metabolism/pharmacology ; Kinetics ; Models, Biological ; Saccharomyces cerevisiae/cytology/drug effects/*growth & development/*metabolism
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  • 4
    Publication Date: 2009-09-11
    Description: It is widely accepted that tissue differentiation and morphogenesis in multicellular organisms are regulated by tightly controlled concentration gradients of morphogens. How exactly these gradients are formed, however, remains unclear. Here we show that Fgf8 morphogen gradients in living zebrafish embryos are established and maintained by two essential factors: fast, free diffusion of single molecules away from the source through extracellular space, and a sink function of the receiving cells, regulated by receptor-mediated endocytosis. Evidence is provided by directly examining single molecules of Fgf8 in living tissue by fluorescence correlation spectroscopy, quantifying their local mobility and concentration with high precision. By changing the degree of uptake of Fgf8 into its target cells, we are able to alter the shape of the Fgf8 gradient. Our results demonstrate that a freely diffusing morphogen can set up concentration gradients in a complex multicellular tissue by a simple source-sink mechanism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yu, Shuizi Rachel -- Burkhardt, Markus -- Nowak, Matthias -- Ries, Jonas -- Petrasek, Zdenek -- Scholpp, Steffen -- Schwille, Petra -- Brand, Michael -- England -- Nature. 2009 Sep 24;461(7263):533-6. doi: 10.1038/nature08391. Epub 2009 Sep 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Developmental Genetics, Biotechnology Center, TUD, Tatzberg 47-49, 01307 Dresden, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19741606" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Diffusion ; Embryo, Nonmammalian/*cytology/embryology/*metabolism ; *Endocytosis ; Extracellular Space/metabolism ; Fibroblast Growth Factors/genetics/*metabolism ; Gastrulation ; Green Fluorescent Proteins/genetics/metabolism ; Models, Biological ; Morphogenesis/*physiology ; Receptors, Fibroblast Growth Factor/metabolism ; Zebrafish/*embryology/*metabolism ; Zebrafish Proteins/genetics/*metabolism
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  • 5
    Publication Date: 2009-06-19
    Description: Several hundred malaria parasite proteins are exported beyond an encasing vacuole and into the cytosol of the host erythrocyte, a process that is central to the virulence and viability of the causative Plasmodium species. The trafficking machinery responsible for this export is unknown. Here we identify in Plasmodium falciparum a translocon of exported proteins (PTEX), which is located in the vacuole membrane. The PTEX complex is ATP-powered, and comprises heat shock protein 101 (HSP101; a ClpA/B-like ATPase from the AAA+ superfamily, of a type commonly associated with protein translocons), a novel protein termed PTEX150 and a known parasite protein, exported protein 2 (EXP2). EXP2 is the potential channel, as it is the membrane-associated component of the core PTEX complex. Two other proteins, a new protein PTEX88 and thioredoxin 2 (TRX2), were also identified as PTEX components. As a common portal for numerous crucial processes, this translocon offers a new avenue for therapeutic intervention.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2725363/" 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/PMC2725363/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉de Koning-Ward, Tania F -- Gilson, Paul R -- Boddey, Justin A -- Rug, Melanie -- Smith, Brian J -- Papenfuss, Anthony T -- Sanders, Paul R -- Lundie, Rachel J -- Maier, Alexander G -- Cowman, Alan F -- Crabb, Brendan S -- R01 AI044008-11/AI/NIAID NIH HHS/ -- R01 AI44008/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Jun 18;459(7249):945-9. doi: 10.1038/nature08104.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Walter & Eliza Hall Institute of Medical Research, Melbourne 3052, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19536257" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Animals, Genetically Modified ; Malaria, Falciparum/*parasitology ; Models, Biological ; Multiprotein Complexes/*chemistry/*metabolism ; Plasmodium falciparum/*metabolism ; Protein Binding ; Protein Transport ; Protozoan Proteins/*metabolism
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  • 6
    Publication Date: 2009-07-17
    Description: In recent years, strikingly consistent patterns of biodiversity have been identified over space, time, organism type and geographical region. A neutral theory (assuming no environmental selection or organismal interactions) has been shown to predict many patterns of ecological biodiversity. This theory is based on a mechanism by which new species arise similarly to point mutations in a population without sexual reproduction. Here we report the simulation of populations with sexual reproduction, mutation and dispersal. We found simulated time dependence of speciation rates, species-area relationships and species abundance distributions consistent with the behaviours found in nature. From our results, we predict steady speciation rates, more species in one-dimensional environments than two-dimensional environments, three scaling regimes of species-area relationships and lognormal distributions of species abundance with an excess of rare species and a tail that may be approximated by Fisher's logarithmic series. These are consistent with dependences reported for, among others, global birds and flowering plants, marine invertebrate fossils, ray-finned fishes, British birds and moths, North American songbirds, mammal fossils from Kansas and Panamanian shrubs. Quantitative comparisons of specific cases are remarkably successful. Our biodiversity results provide additional evidence that species diversity arises without specific physical barriers. This is similar to heavy traffic flows, where traffic jams can form even without accidents or barriers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉de Aguiar, M A M -- Baranger, M -- Baptestini, E M -- Kaufman, L -- Bar-Yam, Y -- England -- Nature. 2009 Jul 16;460(7253):384-7. doi: 10.1038/nature08168.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉New England Complex Systems Institute, Cambridge, Massachusetts 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19606148" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biodiversity ; Disorders of Sex Development ; Extinction, Biological ; *Genetic Speciation ; Genotype ; Haploidy ; Models, Biological ; Mutation/genetics ; Population Dynamics ; Reproduction/genetics/*physiology ; Sexual Behavior, Animal ; Time Factors
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  • 7
    Publication Date: 2009-01-17
    Description: Autonomous and self-sustained oscillator circuits mediating the periodic induction of specific target genes are minimal genetic time-keeping devices found in the central and peripheral circadian clocks. They have attracted significant attention because of their intriguing dynamics and their importance in controlling critical repair, metabolic and signalling pathways. The precise molecular mechanism and expression dynamics of this mammalian circadian clock are still not fully understood. Here we describe a synthetic mammalian oscillator based on an auto-regulated sense-antisense transcription control circuit encoding a positive and a time-delayed negative feedback loop, enabling autonomous, self-sustained and tunable oscillatory gene expression. After detailed systems design with experimental analyses and mathematical modelling, we monitored oscillating concentrations of green fluorescent protein with tunable frequency and amplitude by time-lapse microscopy in real time in individual Chinese hamster ovary cells. The synthetic mammalian clock may provide an insight into the dynamics of natural periodic processes and foster advances in the design of prosthetic networks in future gene and cell therapies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tigges, Marcel -- Marquez-Lago, Tatiana T -- Stelling, Jorg -- Fussenegger, Martin -- England -- Nature. 2009 Jan 15;457(7227):309-12. doi: 10.1038/nature07616.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19148099" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Clocks/*physiology ; CHO Cells ; Circadian Rhythm/*physiology ; Cricetinae ; Cricetulus ; Feedback, Physiological ; Fluorescence ; Gene Expression Regulation/*genetics ; Genes, Synthetic/*genetics ; *Genetic Engineering ; Green Fluorescent Proteins/analysis/genetics/metabolism ; Models, Biological ; Reproducibility of Results ; Time Factors ; Transcription, Genetic
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  • 8
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    Nature Publishing Group (NPG)
    Publication Date: 2009-11-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Todes, Daniel -- England -- Nature. 2009 Nov 5;462(7269):36-7. doi: 10.1038/462036a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of the History of Medicine at Johns Hopkins University, 1900 East Monument Street, Baltimore, Maryland 21205, USA. dtodes@jhmi.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19890312" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Biological Science Disciplines/*history ; *Competitive Behavior ; Cooperative Behavior ; *Cultural Diversity ; Food Supply ; Great Britain ; History, 19th Century ; History, 20th Century ; Humans ; Literature, Modern/history ; Metaphor ; Models, Biological ; Population Density ; Russia ; Selection, Genetic
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  • 9
    Publication Date: 2009-04-17
    Description: During cell division microtubules capture chromosomes by binding to the kinetochore assembled in the centromeric region of chromosomes. In mitosis sister chromatids are captured by microtubules emanating from both spindle poles, a process called bipolar attachment, whereas in meiosis I sisters are attached to microtubules originating from one spindle pole, called monopolar attachment. For determining chromosome orientation, kinetochore geometry or structure might be an important target of regulation. However, the molecular basis of this regulation has remained elusive. Here we show the link between kinetochore orientation and cohesion within the centromere in fission yeast Schizosaccharomyces pombe by strategies developed to visualize the concealed cohesion within the centromere, and to introduce artificial tethers that can influence kinetochore geometry. Our data imply that cohesion at the core centromere induces the mono-orientation of kinetochores whereas cohesion at the peri-centromeric region promotes bi-orientation. Our study may reveal a general mechanism for the geometric regulation of kinetochores, which collaborates with previously defined tension-dependent reorientation machinery.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sakuno, Takeshi -- Tada, Kenji -- Watanabe, Yoshinori -- England -- Nature. 2009 Apr 16;458(7240):852-8. doi: 10.1038/nature07876.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19370027" target="_blank"〉PubMed〈/a〉
    Keywords: Centromere/genetics/*metabolism ; Chromosome Segregation ; Kinetochores/*metabolism ; Meiosis ; Microtubules/metabolism ; Mitosis ; Models, Biological ; Schizosaccharomyces/*cytology
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  • 10
    Publication Date: 2009-01-23
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abbondanzieri, Elio A -- Zhuang, Xiaowei -- England -- Nature. 2009 Jan 22;457(7228):392-3. doi: 10.1038/457392a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19158782" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphatases/*chemistry/*metabolism ; Bacillus Phages/*enzymology ; DNA, Viral/chemistry/metabolism ; Hydrolysis ; Models, Biological ; Protein Structure, Quaternary ; Protein Subunits/chemistry/metabolism ; Virus Assembly
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  • 11
    Publication Date: 2009-02-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Muller-Landau, Helene C -- England -- Nature. 2009 Feb 19;457(7232):969-70. doi: 10.1038/457969a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19225510" target="_blank"〉PubMed〈/a〉
    Keywords: Africa ; Atmosphere/chemistry ; Biomass ; Carbon/analysis/*metabolism ; Carbon Dioxide/analysis/metabolism ; Models, Biological ; Trees/chemistry/growth & development/*metabolism ; *Tropical Climate ; Wilderness
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  • 12
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    Nature Publishing Group (NPG)
    Publication Date: 2009-02-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tonzani, Stefano -- England -- Nature. 2009 Feb 19;457(7232):974. doi: 10.1038/457974a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19225516" target="_blank"〉PubMed〈/a〉
    Keywords: Colloids/*chemistry ; *Magnetics ; Models, Biological ; Nanostructures/chemistry/ultrastructure ; Particle Size ; Water/chemistry
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  • 13
    Publication Date: 2009-04-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kutschera, U -- England -- Nature. 2009 Apr 23;458(7241):967. doi: 10.1038/458967c.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19396120" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; *Competitive Behavior ; Cooperative Behavior ; History, 19th Century ; Models, Biological ; *Selection, Genetic ; *Translating ; *Translations
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  • 14
    Publication Date: 2009-11-10
    Description: Direct reprogramming of somatic cells into induced pluripotent stem (iPS) cells can be achieved by overexpression of Oct4, Sox2, Klf4 and c-Myc transcription factors, but only a minority of donor somatic cells can be reprogrammed to pluripotency. Here we demonstrate that reprogramming by these transcription factors is a continuous stochastic process where almost all mouse donor cells eventually give rise to iPS cells on continued growth and transcription factor expression. Additional inhibition of the p53/p21 pathway or overexpression of Lin28 increased the cell division rate and resulted in an accelerated kinetics of iPS cell formation that was directly proportional to the increase in cell proliferation. In contrast, Nanog overexpression accelerated reprogramming in a predominantly cell-division-rate-independent manner. Quantitative analyses define distinct cell-division-rate-dependent and -independent modes for accelerating the stochastic course of reprogramming, and suggest that the number of cell divisions is a key parameter driving epigenetic reprogramming to pluripotency.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2789972/" 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/PMC2789972/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hanna, Jacob -- Saha, Krishanu -- Pando, Bernardo -- van Zon, Jeroen -- Lengner, Christopher J -- Creyghton, Menno P -- van Oudenaarden, Alexander -- Jaenisch, Rudolf -- R01 CA087869/CA/NCI NIH HHS/ -- R01 CA087869-09/CA/NCI NIH HHS/ -- R01 HD045022/HD/NICHD NIH HHS/ -- R01 HD045022-06/HD/NICHD NIH HHS/ -- R01-CA087869/CA/NCI NIH HHS/ -- R01-HDO45022/PHS HHS/ -- R37 CA084198/CA/NCI NIH HHS/ -- R37 CA084198-09/CA/NCI NIH HHS/ -- R37-CA084198/CA/NCI NIH HHS/ -- U54CA143874/CA/NCI NIH HHS/ -- England -- Nature. 2009 Dec 3;462(7273):595-601. doi: 10.1038/nature08592. Epub 2009 Nov 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA. Hanna@wi.mit.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19898493" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Cell Differentiation ; Cell Division ; Cell Line ; *Cellular Reprogramming ; Gene Expression Regulation, Developmental ; Mice ; Mice, SCID ; Models, Biological ; Pluripotent Stem Cells/*cytology/*metabolism ; Time Factors ; Transcription Factors/genetics/metabolism
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  • 15
    Publication Date: 2009-04-03
    Description: Explaining the ecological causes of evolutionary diversification is a major focus of biology, but surprisingly little has been said about the effects of evolutionary diversification on ecosystems. The number of species in an ecosystem and their traits are key predictors of many ecosystem-level processes, such as rates of productivity, biomass sequestration and decomposition. Here we demonstrate short-term ecosystem-level effects of adaptive radiation in the threespine stickleback (Gasterosteus aculeatus) over the past 10,000 years. These fish have undergone recent parallel diversification in several lakes in coastal British Columbia, resulting in the formation of two specialized species (benthic and limnetic) from a generalist ancestor. Using a mesocosm experiment, we demonstrate that this diversification has strong effects on ecosystems, affecting prey community structure, total primary production, and the nature of dissolved organic materials that regulate the spectral properties of light transmission in the system. However, these ecosystem effects do not simply increase in their relative strength with increasing specialization and species richness; instead, they reflect the complex and indirect consequences of ecosystem engineering by sticklebacks. It is well known that ecological factors influence adaptive radiation. We demonstrate that adaptive radiation, even over short timescales, can have profound effects on ecosystems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harmon, Luke J -- Matthews, Blake -- Des Roches, Simone -- Chase, Jonathan M -- Shurin, Jonathan B -- Schluter, Dolph -- England -- Nature. 2009 Apr 30;458(7242):1167-70. doi: 10.1038/nature07974. Epub 2009 Apr 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844-3051, USA. lukeh@uidaho.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19339968" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biodiversity ; *Biological Evolution ; Biomass ; British Columbia ; *Ecosystem ; Fishes/*classification/*physiology ; Food Chain ; Fresh Water ; Genetic Speciation ; Models, Biological ; Population Density ; Predatory Behavior
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  • 16
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    Nature Publishing Group (NPG)
    Publication Date: 2009-06-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Aguzzi, Adriano -- England -- Nature. 2009 Jun 18;459(7249):924-5. doi: 10.1038/459924a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19536253" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid/metabolism ; Animals ; Humans ; Models, Biological ; Peptides/metabolism ; Prion Diseases/*metabolism/pathology/transmission ; Prions/*chemistry/*metabolism ; Protein Denaturation ; tau Proteins/genetics/metabolism
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  • 17
    Publication Date: 2009-10-02
    Description: Down Syndrome cell adhesion molecule (Dscam) genes encode neuronal cell recognition proteins of the immunoglobulin superfamily. In Drosophila, Dscam1 generates 19,008 different ectodomains by alternative splicing of three exon clusters, each encoding half or a complete variable immunoglobulin domain. Identical isoforms bind to each other, but rarely to isoforms differing at any one of the variable immunoglobulin domains. Binding between isoforms on opposing membranes promotes repulsion. Isoform diversity provides the molecular basis for neurite self-avoidance. Self-avoidance refers to the tendency of branches from the same neuron (self-branches) to selectively avoid one another. To ensure that repulsion is restricted to self-branches, different neurons express different sets of isoforms in a biased stochastic fashion. Genetic studies demonstrated that Dscam1 diversity has a profound role in wiring the fly brain. Here we show how many isoforms are required to provide an identification system that prevents non-self branches from inappropriately recognizing each other. Using homologous recombination, we generated mutant animals encoding 12, 24, 576 and 1,152 potential isoforms. Mutant animals with deletions encoding 4,752 and 14,256 isoforms were also analysed. Branching phenotypes were assessed in three classes of neurons. Branching patterns improved as the potential number of isoforms increased, and this was independent of the identity of the isoforms. Although branching defects in animals with 1,152 potential isoforms remained substantial, animals with 4,752 isoforms were indistinguishable from wild-type controls. Mathematical modelling studies were consistent with the experimental results that thousands of isoforms are necessary to ensure acquisition of unique Dscam1 identities in many neurons. We conclude that thousands of isoforms are essential to provide neurons with a robust discrimination mechanism to distinguish between self and non-self during self-avoidance.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2836808/" 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/PMC2836808/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hattori, Daisuke -- Chen, Yi -- Matthews, Benjamin J -- Salwinski, Lukasz -- Sabatti, Chiara -- Grueber, Wesley B -- Zipursky, S Lawrence -- F31 NS060341/NS/NINDS NIH HHS/ -- R01 DC006485/DC/NIDCD NIH HHS/ -- R01 DC006485-07/DC/NIDCD NIH HHS/ -- R01 HD040279/HD/NICHD NIH HHS/ -- R01 HD040279-05/HD/NICHD NIH HHS/ -- T32 HD007430/HD/NICHD NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Oct 1;461(7264):644-8. doi: 10.1038/nature08431.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19794492" target="_blank"〉PubMed〈/a〉
    Keywords: Alleles ; Alternative Splicing ; Animals ; Brain/cytology/metabolism ; Cell Adhesion Molecules/*chemistry/genetics/*metabolism ; Drosophila Proteins/*chemistry/genetics/*metabolism ; Drosophila melanogaster/*cytology/genetics/*metabolism ; Female ; Male ; Models, Biological ; Mushroom Bodies/cytology/metabolism ; Neurites/*metabolism ; Protein Isoforms/chemistry/genetics/metabolism ; Sequence Deletion ; Stochastic Processes
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  • 18
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    Nature Publishing Group (NPG)
    Publication Date: 2009-09-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nicholls, Henry -- England -- Nature. 2009 Sep 10;461(7261):164-6. doi: 10.1038/461164a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19741680" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Developmental Biology ; Fossils ; Hagfishes/*anatomy & histology/*classification/embryology/genetics ; Head/anatomy & histology ; Humans ; Lampreys/*anatomy & histology/*classification/embryology/genetics ; MicroRNAs/genetics/metabolism ; Models, Biological ; Phylogeny ; Sharks/anatomy & histology/classification/embryology
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  • 19
    Publication Date: 2009-02-20
    Description: The assembly of complex structures out of simple colloidal building blocks is of practical interest for building materials with unique optical properties (for example photonic crystals and DNA biosensors) and is of fundamental importance in improving our understanding of self-assembly processes occurring on molecular to macroscopic length scales. Here we demonstrate a self-assembly principle that is capable of organizing a diverse set of colloidal particles into highly reproducible, rotationally symmetric arrangements. The structures are assembled using the magnetostatic interaction between effectively diamagnetic and paramagnetic particles within a magnetized ferrofluid. The resulting multipolar geometries resemble electrostatic charge configurations such as axial quadrupoles ('Saturn rings'), axial octupoles ('flowers'), linear quadrupoles (poles) and mixed multipole arrangements ('two tone'), which represent just a few examples of the type of structure that can be built using this technique.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Erb, Randall M -- Son, Hui S -- Samanta, Bappaditya -- Rotello, Vincent M -- Yellen, Benjamin B -- England -- Nature. 2009 Feb 19;457(7232):999-1002. doi: 10.1038/nature07766.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Duke University, Department of Mechanical Engineering and Materials Science, Center for Biologically Inspired Materials and Material Systems, Box 90300, Hudson Hall, Durham, North Carolina 27708, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19225522" target="_blank"〉PubMed〈/a〉
    Keywords: Colloids/*chemistry ; *Magnetics ; Microscopy, Electron, Scanning ; Microspheres ; Models, Biological ; Nanostructures/chemistry/ultrastructure ; Particle Size ; Water/chemistry
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  • 20
    Publication Date: 2009-02-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Allen, Nicola J -- Barres, Ben A -- England -- Nature. 2009 Feb 5;457(7230):675-7. doi: 10.1038/457675a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19194443" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astrocytes/physiology ; Biological Evolution ; Brain/*cytology/embryology/pathology/*physiology ; Cell Communication ; Cell Lineage ; Homeostasis ; Humans ; Models, Biological ; Nerve Net/physiology ; Nervous System Diseases/pathology/physiopathology ; Neural Pathways/physiology ; Neuroglia/classification/cytology/pathology/*physiology ; Neurons/cytology/physiology ; Oligodendroglia/pathology/physiology ; Schwann Cells/pathology/physiology
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  • 21
    Publication Date: 2009-09-04
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vasquez, Valeria -- Perozo, Eduardo -- England -- Nature. 2009 Sep 3;461(7260):47-9. doi: 10.1038/461047a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19727188" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/*metabolism ; Crystallography, X-Ray ; Ion Channel Gating/*physiology ; Ion Channels/*chemistry/*metabolism ; Models, Biological ; Models, Molecular ; Mycobacterium tuberculosis/chemistry ; Pressure ; Protein Structure, Quaternary ; Staphylococcus aureus/*chemistry
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  • 22
    Publication Date: 2009-07-25
    Description: Spatially synchronized fluctuations in system state are common in physical and biological systems ranging from individual atoms to species as diverse as viruses, insects and mammals. Although the causal factors are well known for many synchronized phenomena, several processes concurrently have an impact on spatial synchrony of species, making their separate effects and interactions difficult to quantify. Here we develop a general stochastic model of predator-prey spatial dynamics to predict the outcome of a laboratory microcosm experiment testing for interactions among all known synchronizing factors: (1) dispersal of individuals between populations; (2) spatially synchronous fluctuations in exogenous environmental factors (the Moran effect); and (3) interactions with other species (for example, predators) that are themselves spatially synchronized. The Moran effect synchronized populations of the ciliate protist Tetrahymena pyriformis; however, dispersal only synchronized prey populations in the presence of the predator Euplotes patella. Both model and data indicate that synchrony depends on cyclic dynamics generated by the predator. Dispersal, but not the Moran effect, 'phase-locks' cycles, which otherwise become 'decoherent' and drift out of phase. In the absence of cycles, phase-locking is not possible and the synchronizing effect of dispersal is negligible. Interspecific interactions determine population synchrony, not by providing an additional source of synchronized fluctuations, but by altering population dynamics and thereby enhancing the action of dispersal. Our results are robust to wide variation in model parameters representative of many natural predator-prey or host-pathogen systems. This explains why cyclic systems provide many of the most dramatic examples of spatial synchrony in nature.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vasseur, David A -- Fox, Jeremy W -- England -- Nature. 2009 Aug 20;460(7258):1007-10. doi: 10.1038/nature08208. Epub 2009 Jul 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520, USA. david.vasseur@yale.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19626006" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Euplotes/*physiology ; *Food Chain ; Models, Biological ; Population Dynamics ; Predatory Behavior/*physiology ; Stochastic Processes ; Tetrahymena pyriformis/*physiology
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  • 23
    Publication Date: 2009-06-12
    Description: Natural products containing phosphorus-carbon bonds have found widespread use in medicine and agriculture. One such compound, phosphinothricin tripeptide, contains the unusual amino acid phosphinothricin attached to two alanine residues. Synthetic phosphinothricin (glufosinate) is a component of two top-selling herbicides (Basta and Liberty), and is widely used with resistant transgenic crops including corn, cotton and canola. Recent genetic and biochemical studies showed that during phosphinothricin tripeptide biosynthesis 2-hydroxyethylphosphonate (HEP) is converted to hydroxymethylphosphonate (HMP). Here we report the in vitro reconstitution of this unprecedented C(sp(3))-C(sp(3)) bond cleavage reaction and X-ray crystal structures of the enzyme. The protein is a mononuclear non-haem iron(ii)-dependent dioxygenase that converts HEP to HMP and formate. In contrast to most other members of this family, the oxidative consumption of HEP does not require additional cofactors or the input of exogenous electrons. The current study expands the scope of reactions catalysed by the 2-His-1-carboxylate mononuclear non-haem iron family of enzymes.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874955/" 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/PMC2874955/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cicchillo, Robert M -- Zhang, Houjin -- Blodgett, Joshua A V -- Whitteck, John T -- Li, Gongyong -- Nair, Satish K -- van der Donk, Wilfred A -- Metcalf, William W -- P01 GM077596/GM/NIGMS NIH HHS/ -- P01 GM077596-03/GM/NIGMS NIH HHS/ -- R01 GM059334/GM/NIGMS NIH HHS/ -- R01 GM059334-09/GM/NIGMS NIH HHS/ -- R01 GM59334/GM/NIGMS NIH HHS/ -- England -- Nature. 2009 Jun 11;459(7248):871-4. doi: 10.1038/nature07972.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19516340" target="_blank"〉PubMed〈/a〉
    Keywords: Aminobutyrates/*chemistry/*metabolism ; Biocatalysis ; Crystallography, X-Ray ; Dioxygenases/chemistry/genetics/*metabolism ; Escherichia coli ; Formates/metabolism ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Models, Biological ; Models, Molecular ; Molecular Conformation ; Organophosphonates/metabolism
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  • 24
    Publication Date: 2009-08-14
    Description: Ecological communities characteristically contain a wide diversity of species with important functional, economic and aesthetic value. Ecologists have long questioned how this diversity is maintained. Classic theory shows that stable coexistence requires competitors to differ in their niches; this has motivated numerous investigations of ecological differences presumed to maintain diversity. That niche differences are key to coexistence, however, has recently been challenged by the neutral theory of biodiversity, which explains coexistence with the equivalence of competitors. The ensuing controversy has motivated calls for a better understanding of the collective importance of niche differences for the diversity observed in ecological communities. Here we integrate theory and experimentation to show that niche differences collectively stabilize the dynamics of experimental communities of serpentine annual plants. We used field-parameterized population models to develop a null expectation for community dynamics without the stabilizing effects of niche differences. The population growth rates predicted by this null model varied by several orders of magnitude between species, which is sufficient for rapid competitive exclusion. Moreover, after two generations of community change in the field, Shannon diversity was over 50 per cent greater in communities stabilized by niche differences relative to those exhibiting dynamics predicted by the null model. Finally, in an experiment manipulating species' relative abundances, population growth rates increased when species became rare--the demographic signature of niche differences. Our work thus provides strong evidence that species differences have a critical role in stabilizing species diversity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Levine, Jonathan M -- HilleRisLambers, Janneke -- England -- Nature. 2009 Sep 10;461(7261):254-7. doi: 10.1038/nature08251. Epub 2009 Aug 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, USA. levine@lifesci.ucsb.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19675568" target="_blank"〉PubMed〈/a〉
    Keywords: *Biodiversity ; California ; *Ecosystem ; Models, Biological ; Plant Development ; *Plant Physiological Phenomena ; Plants/classification ; Population Dynamics ; Seeds/physiology
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  • 25
    Publication Date: 2009-02-20
    Description: The response of terrestrial vegetation to a globally changing environment is central to predictions of future levels of atmospheric carbon dioxide. The role of tropical forests is critical because they are carbon-dense and highly productive. Inventory plots across Amazonia show that old-growth forests have increased in carbon storage over recent decades, but the response of one-third of the world's tropical forests in Africa is largely unknown owing to an absence of spatially extensive observation networks. Here we report data from a ten-country network of long-term monitoring plots in African tropical forests. We find that across 79 plots (163 ha) above-ground carbon storage in live trees increased by 0.63 Mg C ha(-1) yr(-1) between 1968 and 2007 (95% confidence interval (CI), 0.22-0.94; mean interval, 1987-96). Extrapolation to unmeasured forest components (live roots, small trees, necromass) and scaling to the continent implies a total increase in carbon storage in African tropical forest trees of 0.34 Pg C yr(-1) (CI, 0.15-0.43). These reported changes in carbon storage are similar to those reported for Amazonian forests per unit area, providing evidence that increasing carbon storage in old-growth forests is a pan-tropical phenomenon. Indeed, combining all standardized inventory data from this study and from tropical America and Asia together yields a comparable figure of 0.49 Mg C ha(-1) yr(-1) (n = 156; 562 ha; CI, 0.29-0.66; mean interval, 1987-97). This indicates a carbon sink of 1.3 Pg C yr(-1) (CI, 0.8-1.6) across all tropical forests during recent decades. Taxon-specific analyses of African inventory and other data suggest that widespread changes in resource availability, such as increasing atmospheric carbon dioxide concentrations, may be the cause of the increase in carbon stocks, as some theory and models predict.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lewis, Simon L -- Lopez-Gonzalez, Gabriela -- Sonke, Bonaventure -- Affum-Baffoe, Kofi -- Baker, Timothy R -- Ojo, Lucas O -- Phillips, Oliver L -- Reitsma, Jan M -- White, Lee -- Comiskey, James A -- Djuikouo K, Marie-Noel -- Ewango, Corneille E N -- Feldpausch, Ted R -- Hamilton, Alan C -- Gloor, Manuel -- Hart, Terese -- Hladik, Annette -- Lloyd, Jon -- Lovett, Jon C -- Makana, Jean-Remy -- Malhi, Yadvinder -- Mbago, Frank M -- Ndangalasi, Henry J -- Peacock, Julie -- Peh, Kelvin S-H -- Sheil, Douglas -- Sunderland, Terry -- Swaine, Michael D -- Taplin, James -- Taylor, David -- Thomas, Sean C -- Votere, Raymond -- Woll, Hannsjorg -- England -- Nature. 2009 Feb 19;457(7232):1003-6. doi: 10.1038/nature07771.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Earth and Biosphere Institute, School of Geography, University of Leeds, Leeds LS2 9JT, UK. s.l.lewis@leeds.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19225523" target="_blank"〉PubMed〈/a〉
    Keywords: Africa ; Atmosphere/chemistry ; Biomass ; Carbon/analysis/*metabolism ; Carbon Dioxide/analysis/metabolism ; Models, Biological ; Trees/anatomy & histology/chemistry/growth & development/*metabolism ; *Tropical Climate ; Wilderness ; Wood/analysis/chemistry
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  • 26
    Publication Date: 2009-06-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Clark, Andrew J -- Summers, Adam P -- England -- Nature. 2009 Jun 18;459(7249):919-20. doi: 10.1038/459919a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19536249" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biomechanical Phenomena ; Body Weight ; Friction ; Gait/physiology ; Locomotion/*physiology ; Models, Biological ; Snakes/*physiology
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  • 27
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    Nature Publishing Group (NPG)
    Publication Date: 2009-06-12
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Seastedt, Tim -- England -- Nature. 2009 Jun 11;459(7248):783-4. doi: 10.1038/459783a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19516327" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Ecosystem ; Europe ; Models, Biological ; *Plant Development ; Plants/*microbiology ; Population Growth ; United States
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  • 28
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    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2009-05-02
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Seehausen, Ole -- England -- Nature. 2009 Apr 30;458(7242):1122-3. doi: 10.1038/4581122a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19407790" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biodiversity ; *Biological Evolution ; British Columbia ; *Ecosystem ; Fishes/*classification/*physiology ; Food Chain ; Fresh Water ; Genetic Speciation ; Models, Biological
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  • 29
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    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2009-01-17
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sendtner, Michael -- England -- Nature. 2009 Jan 15;457(7227):269-70. doi: 10.1038/457269a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19148087" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Cell Differentiation/drug effects ; Cell Separation ; *Cellular Reprogramming/drug effects ; Child ; Female ; Fibroblasts/cytology ; Humans ; Mice ; Models, Biological ; Motor Neurons/drug effects/metabolism/*pathology ; Muscular Atrophy, Spinal/drug therapy/metabolism/*pathology ; Pluripotent Stem Cells/cytology/drug effects/metabolism/*pathology ; Skin/*cytology ; Survival of Motor Neuron 1 Protein/genetics/metabolism
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  • 30
    Publication Date: 2009-07-03
    Description: Environmental conditions during the past 24 million years are thought to have been favourable for enhanced rates of atmospheric carbon dioxide drawdown by silicate chemical weathering. Proxy records indicate, however, that the Earth's atmospheric carbon dioxide concentrations did not fall below about 200-250 parts per million during this period. The stabilization of atmospheric carbon dioxide concentrations near this minimum value suggests that strong negative feedback mechanisms inhibited further drawdown of atmospheric carbon dioxide by high rates of global silicate rock weathering. Here we investigate one possible negative feedback mechanism, occurring under relatively low carbon dioxide concentrations and in warm climates, that is related to terrestrial plant productivity and its role in the decomposition of silicate minerals. We use simulations of terrestrial and geochemical carbon cycles and available experimental evidence to show that vegetation activity in upland regions of active orogens was severely limited by near-starvation of carbon dioxide in combination with global warmth over this period. These conditions diminished biotic-driven silicate rock weathering and thereby attenuated an important long-term carbon dioxide sink. Although our modelling results are semi-quantitative and do not capture the full range of biogeochemical feedbacks that could influence the climate, our analysis indicates that the dynamic equilibrium between plants, climate and the geosphere probably buffered the minimum atmospheric carbon dioxide concentrations over the past 24 million years.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pagani, Mark -- Caldeira, Ken -- Berner, Robert -- Beerling, David J -- England -- Nature. 2009 Jul 2;460(7251):85-8. doi: 10.1038/nature08133.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520, USA. mark.pagani@yale.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19571882" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Atmosphere/*chemistry ; Biomass ; Carbon Dioxide/*analysis ; Climate ; Eukaryota ; Geologic Sediments/*chemistry ; Geology ; History, Ancient ; Ice Cover ; Models, Biological ; Plant Leaves/metabolism ; Plant Roots/growth & development ; Plant Transpiration ; Plants/*metabolism ; Silicates/*chemistry
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  • 31
    Publication Date: 2009-03-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Friend, Stephen -- Schadt, Eric -- England -- Nature. 2009 Mar 5;458(7234):13. doi: 10.1038/458013a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19262635" target="_blank"〉PubMed〈/a〉
    Keywords: *Access to Information ; Animals ; *Biomedical Research ; Humans ; *Internet ; Mice ; Models, Biological ; Time Factors
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  • 32
    Publication Date: 2009-11-20
    Description: Genomic DNA is replicated by two DNA polymerase molecules, one of which works in close association with the helicase to copy the leading-strand template in a continuous manner while the second copies the already unwound lagging-strand template in a discontinuous manner through the synthesis of Okazaki fragments. Considering that the lagging-strand polymerase has to recycle after the completion of every Okazaki fragment through the slow steps of primer synthesis and hand-off to the polymerase, it is not understood how the two strands are synthesized with the same net rate. Here we show, using the T7 replication proteins, that RNA primers are made 'on the fly' during ongoing DNA synthesis and that the leading-strand T7 replisome does not pause during primer synthesis, contrary to previous reports. Instead, the leading-strand polymerase remains limited by the speed of the helicase; it therefore synthesizes DNA more slowly than the lagging-strand polymerase. We show that the primase-helicase T7 gp4 maintains contact with the priming sequence during ongoing DNA synthesis; the nascent lagging-strand template therefore organizes into a priming loop that keeps the primer in physical proximity to the replication complex. Our findings provide three synergistic mechanisms of coordination: first, primers are made concomitantly with DNA synthesis; second, the priming loop ensures efficient primer use and hand-off to the polymerase; and third, the lagging-strand polymerase copies DNA faster, which allows it to keep up with leading-strand DNA synthesis overall.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2896039/" 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/PMC2896039/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pandey, Manjula -- Syed, Salman -- Donmez, Ilker -- Patel, Gayatri -- Ha, Taekjip -- Patel, Smita S -- GM065367/GM/NIGMS NIH HHS/ -- GM55310/GM/NIGMS NIH HHS/ -- R01 GM055310/GM/NIGMS NIH HHS/ -- R01 GM055310-14/GM/NIGMS NIH HHS/ -- R01 GM065367/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Dec 17;462(7275):940-3. doi: 10.1038/nature08611. Epub 2009 Nov 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19924126" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteriophage T7/*enzymology/genetics/*physiology ; DNA Primase/chemistry/metabolism ; DNA Replication/*physiology ; DNA, Viral/biosynthesis/metabolism ; DNA-Directed DNA Polymerase/chemistry/metabolism ; Fluorescence Resonance Energy Transfer ; Kinetics ; Models, Biological ; Multienzyme Complexes/chemistry/metabolism ; Protein Structure, Tertiary ; RNA/biosynthesis ; Time Factors
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  • 33
    Publication Date: 2009-08-25
    Description: The ability of cells to sense and respond to mechanical force underlies diverse processes such as touch and hearing in animals, gravitropism in plants, and bacterial osmoregulation. In bacteria, mechanosensation is mediated by the mechanosensitive channels of large (MscL), small (MscS), potassium-dependent (MscK) and mini (MscM) conductances. These channels act as 'emergency relief valves' protecting bacteria from lysis upon acute osmotic down-shock. Among them, MscL has been intensively studied since the original identification and characterization 15 years ago. MscL is reversibly and directly gated by changes in membrane tension. In the open state, MscL forms a non-selective 3 nS conductance channel which gates at tensions close to the lytic limit of the bacterial membrane. An earlier crystal structure at 3.5 A resolution of a pentameric MscL from Mycobacterium tuberculosis represents a closed-state or non-conducting conformation. MscL has a complex gating behaviour; it exhibits several intermediates between the closed and open states, including one putative non-conductive expanded state and at least three sub-conducting states. Although our understanding of the closed and open states of MscL has been increasing, little is known about the structures of the intermediate states despite their importance in elucidating the complete gating process of MscL. Here we present the crystal structure of a carboxy-terminal truncation mutant (Delta95-120) of MscL from Staphylococcus aureus (SaMscL(CDelta26)) at 3.8 A resolution. Notably, SaMscL(CDelta26) forms a tetrameric channel with both transmembrane helices tilted away from the membrane normal at angles close to that inferred for the open state, probably corresponding to a non-conductive but partially expanded intermediate state.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737600/" 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/PMC2737600/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Zhenfeng -- Gandhi, Chris S -- Rees, Douglas C -- GM084211/GM/NIGMS NIH HHS/ -- R01 GM084211/GM/NIGMS NIH HHS/ -- R01 GM084211-01/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Sep 3;461(7260):120-4. doi: 10.1038/nature08277. Epub 2009 Aug 23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19701184" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Proteins/*chemistry/metabolism ; Crystallography, X-Ray ; Ion Channel Gating ; Ion Channels/*chemistry/metabolism ; Models, Biological ; Models, Molecular ; Molecular Sequence Data ; Mycobacterium tuberculosis/chemistry/metabolism ; Pressure ; Protein Structure, Quaternary ; Staphylococcus aureus/*chemistry ; Structural Homology, Protein
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  • 34
    Publication Date: 2009-11-06
    Description: Bet hedging-stochastic switching between phenotypic states-is a canonical example of an evolutionary adaptation that facilitates persistence in the face of fluctuating environmental conditions. Although bet hedging is found in organisms ranging from bacteria to humans, direct evidence for an adaptive origin of this behaviour is lacking. Here we report the de novo evolution of bet hedging in experimental bacterial populations. Bacteria were subjected to an environment that continually favoured new phenotypic states. Initially, our regime drove the successive evolution of novel phenotypes by mutation and selection; however, in two (of 12) replicates this trend was broken by the evolution of bet-hedging genotypes that persisted because of rapid stochastic phenotype switching. Genome re-sequencing of one of these switching types revealed nine mutations that distinguished it from the ancestor. The final mutation was both necessary and sufficient for rapid phenotype switching; nonetheless, the evolution of bet hedging was contingent upon earlier mutations that altered the relative fitness effect of the final mutation. These findings capture the adaptive evolution of bet hedging in the simplest of organisms, and suggest that risk-spreading strategies may have been among the earliest evolutionary solutions to life in fluctuating environments.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beaumont, Hubertus J E -- Gallie, Jenna -- Kost, Christian -- Ferguson, Gayle C -- Rainey, Paul B -- England -- Nature. 2009 Nov 5;462(7269):90-3. doi: 10.1038/nature08504.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉New Zealand Institute for Advanced Study and Allan Wilson Centre for Molecular Ecology & Evolution, Massey University, Private Bag 102904, North Shore Mail Centre, North Shore City 0745, Auckland, New Zealand. h.j.e.beaumont@biology.leidenuniv.nl〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19890329" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Physiological/genetics/*physiology ; *Biological Evolution ; Cell Shape ; Colony Count, Microbial ; *Environment ; Genes, Bacterial/genetics ; Genetic Fitness ; Genotype ; Models, Biological ; Phenotype ; Pseudomonas fluorescens/cytology/*genetics/growth & development/*physiology ; Selection, Genetic ; Stochastic Processes
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  • 35
    facet.materialart.
    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2009-10-09
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shapley, Robert -- England -- Nature. 2009 Oct 8;461(7265):737-9. doi: 10.1038/461737a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19812661" target="_blank"〉PubMed〈/a〉
    Keywords: *Aging ; Animals ; Color Perception/genetics/physiology ; Color Vision/genetics/physiology ; Color Vision Defects/congenital/*genetics/physiopathology/*therapy ; Female ; *Genetic Therapy ; Humans ; Male ; Models, Biological ; Opsins/*genetics/*metabolism ; Retinal Cone Photoreceptor Cells/metabolism ; Saimiri/*genetics/physiology ; Treatment Outcome
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  • 36
    Publication Date: 2009-12-18
    Description: DNA double-strand breaks (DSBs) are highly cytotoxic lesions that are generated by ionizing radiation and various DNA-damaging chemicals. Following DSB formation, cells activate the DNA-damage response (DDR) protein kinases ATM, ATR and DNA-PK (also known as PRKDC). These then trigger histone H2AX (also known as H2AFX) phosphorylation and the accumulation of proteins such as MDC1, 53BP1 (also known as TP53BP1), BRCA1, CtIP (also known as RBBP8), RNF8 and RNF168/RIDDLIN into ionizing radiation-induced foci (IRIF) that amplify DSB signalling and promote DSB repair. Attachment of small ubiquitin-related modifier (SUMO) to target proteins controls diverse cellular functions. Here, we show that SUMO1, SUMO2 and SUMO3 accumulate at DSB sites in mammalian cells, with SUMO1 and SUMO2/3 accrual requiring the E3 ligase enzymes PIAS4 and PIAS1. We also establish that PIAS1 and PIAS4 are recruited to damage sites via mechanisms requiring their SAP domains, and are needed for the productive association of 53BP1, BRCA1 and RNF168 with such regions. Furthermore, we show that PIAS1 and PIAS4 promote DSB repair and confer ionizing radiation resistance. Finally, we establish that PIAS1 and PIAS4 are required for effective ubiquitin-adduct formation mediated by RNF8, RNF168 and BRCA1 at sites of DNA damage. These findings thus identify PIAS1 and PIAS4 as components of the DDR and reveal how protein recruitment to DSB sites is controlled by coordinated SUMOylation and ubiquitylation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904806/" 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/PMC2904806/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Galanty, Yaron -- Belotserkovskaya, Rimma -- Coates, Julia -- Polo, Sophie -- Miller, Kyle M -- Jackson, Stephen P -- 086861/Wellcome Trust/United Kingdom -- 11224/Cancer Research UK/United Kingdom -- A5290/Cancer Research UK/United Kingdom -- Cancer Research UK/United Kingdom -- England -- Nature. 2009 Dec 17;462(7275):935-9. doi: 10.1038/nature08657.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Wellcome Trust and Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016603" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; BRCA1 Protein/metabolism ; Cell Line ; Cell Line, Tumor ; *DNA Breaks, Double-Stranded ; *DNA Repair ; DNA-Binding Proteins/genetics/metabolism ; Fluorescence Recovery After Photobleaching ; Humans ; Intracellular Signaling Peptides and Proteins/genetics/metabolism ; Models, Biological ; Phosphorylation ; Protein Inhibitors of Activated STAT/chemistry/genetics/*metabolism ; Protein Structure, Tertiary ; Replication Protein A/metabolism ; Small Ubiquitin-Related Modifier Proteins/genetics/*metabolism ; Ubiquitin-Conjugating Enzymes/genetics/metabolism ; Ubiquitin-Protein Ligases/metabolism ; Ubiquitination
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  • 37
    Publication Date: 2009-10-09
    Description: RNA silencing is a conserved regulatory mechanism in fungi, plants and animals that regulates gene expression and defence against viruses and transgenes. Small silencing RNAs of approximately 20-30 nucleotides and their associated effector proteins, the Argonaute family proteins, are the central components in RNA silencing. A subset of small RNAs, such as microRNAs and small interfering RNAs (siRNAs) in plants, Piwi-interacting RNAs in animals and siRNAs in Drosophila, requires an additional crucial step for their maturation; that is, 2'-O-methylation on the 3' terminal nucleotide. A conserved S-adenosyl-l-methionine-dependent RNA methyltransferase, HUA ENHANCER 1 (HEN1), and its homologues are responsible for this specific modification. Here we report the 3.1 A crystal structure of full-length HEN1 from Arabidopsis in complex with a 22-nucleotide small RNA duplex and cofactor product S-adenosyl-l-homocysteine. Highly cooperative recognition of the small RNA substrate by multiple RNA binding domains and the methyltransferase domain in HEN1 measures the length of the RNA duplex and determines the substrate specificity. Metal ion coordination by both 2' and 3' hydroxyls on the 3'-terminal nucleotide and four invariant residues in the active site of the methyltransferase domain suggests a novel Mg(2+)-dependent 2'-O-methylation mechanism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Huang, Ying -- Ji, Lijuan -- Huang, Qichen -- Vassylyev, Dmitry G -- Chen, Xuemei -- Ma, Jin-Biao -- GM074252/GM/NIGMS NIH HHS/ -- R01 GM074840/GM/NIGMS NIH HHS/ -- England -- Nature. 2009 Oct 8;461(7265):823-7. doi: 10.1038/nature08433.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19812675" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Arabidopsis/*enzymology/genetics ; Arabidopsis Proteins/*chemistry/genetics/*metabolism ; Biocatalysis ; Catalytic Domain ; Crystallography, X-Ray ; Magnesium/metabolism ; Methylation ; Methyltransferases/*chemistry/*metabolism ; Models, Biological ; Models, Molecular ; Protein Structure, Tertiary ; RNA/genetics/*metabolism ; RNA-Binding Proteins/chemistry/metabolism ; S-Adenosylhomocysteine/chemistry/metabolism ; Structure-Activity Relationship ; Substrate Specificity
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  • 38
    Publication Date: 2009-06-10
    Description: Chromosomal instability (CIN) is a hallmark of many tumours and correlates with the presence of extra centrosomes. However, a direct mechanistic link between extra centrosomes and CIN has not been established. It has been proposed that extra centrosomes generate CIN by promoting multipolar anaphase, a highly abnormal division that produces three or more aneuploid daughter cells. Here we use long-term live-cell imaging to demonstrate that cells with multiple centrosomes rarely undergo multipolar cell divisions, and the progeny of these divisions are typically inviable. Thus, multipolar divisions cannot explain observed rates of CIN. In contrast, we observe that CIN cells with extra centrosomes routinely undergo bipolar cell divisions, but display a significantly increased frequency of lagging chromosomes during anaphase. To define the mechanism underlying this mitotic defect, we generated cells that differ only in their centrosome number. We demonstrate that extra centrosomes alone are sufficient to promote chromosome missegregation during bipolar cell division. These segregation errors are a consequence of cells passing through a transient 'multipolar spindle intermediate' in which merotelic kinetochore-microtubule attachment errors accumulate before centrosome clustering and anaphase. These findings provide a direct mechanistic link between extra centrosomes and CIN, two common characteristics of solid tumours. We propose that this mechanism may be a common underlying cause of CIN in human cancer.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743290/" 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/PMC2743290/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ganem, Neil J -- Godinho, Susana A -- Pellman, David -- GM083299/GM/NIGMS NIH HHS/ -- R01 GM083299/GM/NIGMS NIH HHS/ -- R01 GM083299-12/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Jul 9;460(7252):278-82. doi: 10.1038/nature08136. Epub 2009 Jun 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Children's Hospital, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19506557" target="_blank"〉PubMed〈/a〉
    Keywords: Anaphase ; Cell Line, Tumor ; Centrosome/*physiology ; Chromosomal Instability/*physiology ; Chromosome Segregation ; Humans ; Kinetochores/metabolism ; Microtubules/metabolism ; Models, Biological ; Neoplasms/genetics/pathology ; Spindle Apparatus/metabolism ; Time Factors
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  • 39
    Publication Date: 2009-07-07
    Description: MicroRNAs (miRNAs) are regulators of myriad cellular events, but evidence for a single miRNA that can efficiently differentiate multipotent stem cells into a specific lineage or regulate direct reprogramming of cells into an alternative cell fate has been elusive. Here we show that miR-145 and miR-143 are co-transcribed in multipotent murine cardiac progenitors before becoming localized to smooth muscle cells, including neural crest stem-cell-derived vascular smooth muscle cells. miR-145 and miR-143 were direct transcriptional targets of serum response factor, myocardin and Nkx2-5 (NK2 transcription factor related, locus 5) and were downregulated in injured or atherosclerotic vessels containing proliferating, less differentiated smooth muscle cells. miR-145 was necessary for myocardin-induced reprogramming of adult fibroblasts into smooth muscle cells and sufficient to induce differentiation of multipotent neural crest stem cells into vascular smooth muscle. Furthermore, miR-145 and miR-143 cooperatively targeted a network of transcription factors, including Klf4 (Kruppel-like factor 4), myocardin and Elk-1 (ELK1, member of ETS oncogene family), to promote differentiation and repress proliferation of smooth muscle cells. These findings demonstrate that miR-145 can direct the smooth muscle fate and that miR-145 and miR-143 function to regulate the quiescent versus proliferative phenotype of smooth muscle cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769203/" 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/PMC2769203/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cordes, Kimberly R -- Sheehy, Neil T -- White, Mark P -- Berry, Emily C -- Morton, Sarah U -- Muth, Alecia N -- Lee, Ting-Hein -- Miano, Joseph M -- Ivey, Kathryn N -- Srivastava, Deepak -- C06 RR018928/RR/NCRR NIH HHS/ -- HL091168/HL/NHLBI NIH HHS/ -- HL62572/HL/NHLBI NIH HHS/ -- R01 HL062572/HL/NHLBI NIH HHS/ -- R01 HL062572-12/HL/NHLBI NIH HHS/ -- R01 HL091168/HL/NHLBI NIH HHS/ -- R01 HL091168-01A1/HL/NHLBI NIH HHS/ -- England -- Nature. 2009 Aug 6;460(7256):705-10. doi: 10.1038/nature08195. Epub 2009 Jul 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Gladstone Institute of Cardiovascular Disease, San Francisco, California 94158, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19578358" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Differentiation ; *Cell Lineage ; Cell Proliferation ; Female ; Gene Expression Regulation ; Homeodomain Proteins/metabolism ; Male ; Mice ; Mice, Transgenic ; MicroRNAs/genetics/*metabolism ; Models, Biological ; Myocardium/metabolism ; Myocytes, Smooth Muscle/*cytology/*metabolism ; Transcription Factors/metabolism ; Transcription, Genetic ; Vascular Diseases/metabolism ; ets-Domain Protein Elk-4/metabolism
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  • 40
    facet.materialart.
    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2009-06-12
    Description: 〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3808163/" 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/PMC3808163/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Madura, Kiran -- R01 CA083875/CA/NCI NIH HHS/ -- England -- Nature. 2009 Jun 11;459(7248):787-8. doi: 10.1038/459787a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19516331" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphatases/chemistry/*metabolism ; Humans ; Models, Biological ; Molecular Chaperones/*metabolism ; Proteasome Endopeptidase Complex/*biosynthesis/*chemistry/metabolism ; Protein Binding ; Saccharomyces cerevisiae/*enzymology/genetics ; Saccharomyces cerevisiae Proteins/metabolism
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  • 41
    Publication Date: 2009-07-17
    Description: DNA-damage-induced SOS mutations arise when Escherichia coli DNA polymerase (pol) V, activated by a RecA nucleoprotein filament (RecA*), catalyses translesion DNA synthesis. Here we address two longstanding enigmatic aspects of SOS mutagenesis, the molecular composition of mutagenically active pol V and the role of RecA*. We show that RecA* transfers a single RecA-ATP stoichiometrically from its DNA 3'-end to free pol V (UmuD'(2)C) to form an active mutasome (pol V Mut) with the composition UmuD'(2)C-RecA-ATP. Pol V Mut catalyses TLS in the absence of RecA* and deactivates rapidly upon dissociation from DNA. Deactivation occurs more slowly in the absence of DNA synthesis, while retaining RecA-ATP in the complex. Reactivation of pol V Mut is triggered by replacement of RecA-ATP from RecA*. Thus, the principal role of RecA* in SOS mutagenesis is to transfer RecA-ATP to pol V, and thus generate active mutasomal complex for translesion synthesis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2731490/" 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/PMC2731490/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jiang, Qingfei -- Karata, Kiyonobu -- Woodgate, Roger -- Cox, Michael M -- Goodman, Myron F -- ES12259/ES/NIEHS NIH HHS/ -- GM32335/GM/NIGMS NIH HHS/ -- R01 ES012259/ES/NIEHS NIH HHS/ -- R01 ES012259-20/ES/NIEHS NIH HHS/ -- R37 GM021422/GM/NIGMS NIH HHS/ -- R37 GM021422-33/GM/NIGMS NIH HHS/ -- R37GM21422/GM/NIGMS NIH HHS/ -- Intramural NIH HHS/ -- England -- Nature. 2009 Jul 16;460(7253):359-63. doi: 10.1038/nature08178.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, University of Southern California, University Park, Los Angeles, California 90089-2910, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19606142" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/*metabolism ; DNA Replication ; DNA, Single-Stranded/metabolism ; DNA-Directed DNA Polymerase/*chemistry/genetics/*metabolism ; Enzyme Activation ; Escherichia coli/*enzymology ; Escherichia coli Proteins/*chemistry/genetics/*metabolism ; Models, Biological ; Molecular Weight ; Multienzyme Complexes/chemistry/metabolism ; Rec A Recombinases/*metabolism ; SOS Response (Genetics) ; Transcriptional Activation
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  • 42
    Publication Date: 2009-03-28
    Description: Human spliceosomal U1 small nuclear ribonucleoprotein particles (snRNPs), which consist of U1 small nuclear RNA and ten proteins, recognize the 5' splice site within precursor messenger RNAs and initiate the assembly of the spliceosome for intron excision. An electron density map of the functional core of U1 snRNP at 5.5 A resolution has enabled us to build the RNA and, in conjunction with site-specific labelling of individual proteins, to place the seven Sm proteins, U1-C and U1-70K into the map. Here we present the detailed structure of a spliceosomal snRNP, revealing a hierarchical network of intricate interactions between subunits. A striking feature is the amino (N)-terminal polypeptide of U1-70K, which extends over a distance of 180 A from its RNA binding domain, wraps around the core domain consisting of the seven Sm proteins and finally contacts U1-C, which is crucial for 5'-splice-site recognition. The structure of U1 snRNP provides insights into U1 snRNP assembly and suggests a possible mechanism of 5'-splice-site recognition.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673513/" 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/PMC2673513/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pomeranz Krummel, Daniel A -- Oubridge, Chris -- Leung, Adelaine K W -- Li, Jade -- Nagai, Kiyoshi -- MC_U105184330/Medical Research Council/United Kingdom -- U.1051.04.016(78933)/Medical Research Council/United Kingdom -- Medical Research Council/United Kingdom -- England -- Nature. 2009 Mar 26;458(7237):475-80. doi: 10.1038/nature07851.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19325628" target="_blank"〉PubMed〈/a〉
    Keywords: Crystallography, X-Ray ; Humans ; Models, Biological ; Models, Molecular ; Nucleic Acid Conformation ; Protein Folding ; Protein Structure, Tertiary ; RNA Splice Sites ; RNA Splicing ; RNA, Small Nuclear/chemistry ; Ribonucleoprotein, U1 Small Nuclear/*chemistry/metabolism ; Spliceosomes/*chemistry ; Zinc Fingers
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  • 43
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    Nature Publishing Group (NPG)
    Publication Date: 2009-07-17
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Powell, Kendall -- England -- Nature. 2009 Jul 16;460(7253):318-20. doi: 10.1038/460318a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19606122" target="_blank"〉PubMed〈/a〉
    Keywords: Biophysical Phenomena ; Cell Membrane/chemistry/physiology ; Cell Shape/*physiology ; GTPase-Activating Proteins/metabolism ; Golgi Apparatus/physiology ; Models, Biological ; Nerve Tissue Proteins/chemistry/metabolism ; Organelle Shape/*physiology
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  • 44
    Publication Date: 2009-09-22
    Description: Polycomb group proteins have an essential role in the epigenetic maintenance of repressive chromatin states. The gene-silencing activity of the Polycomb repressive complex 2 (PRC2) depends on its ability to trimethylate lysine 27 of histone H3 (H3K27) by the catalytic SET domain of the EZH2 subunit, and at least two other subunits of the complex: SUZ12 and EED. Here we show that the carboxy-terminal domain of EED specifically binds to histone tails carrying trimethyl-lysine residues associated with repressive chromatin marks, and that this leads to the allosteric activation of the methyltransferase activity of PRC2. Mutations in EED that prevent it from recognizing repressive trimethyl-lysine marks abolish the activation of PRC2 in vitro and, in Drosophila, reduce global methylation and disrupt development. These findings suggest a model for the propagation of the H3K27me3 mark that accounts for the maintenance of repressive chromatin domains and for the transmission of a histone modification from mother to daughter cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3772642/" 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/PMC3772642/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Margueron, Raphael -- Justin, Neil -- Ohno, Katsuhito -- Sharpe, Miriam L -- Son, Jinsook -- Drury, William J 3rd -- Voigt, Philipp -- Martin, Stephen R -- Taylor, William R -- De Marco, Valeria -- Pirrotta, Vincenzo -- Reinberg, Danny -- Gamblin, Steven J -- GM064844/GM/NIGMS NIH HHS/ -- GM37120/GM/NIGMS NIH HHS/ -- MC_U117584222/Medical Research Council/United Kingdom -- R01 GM064844/GM/NIGMS NIH HHS/ -- R01 GM064844-08/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- Medical Research Council/United Kingdom -- England -- Nature. 2009 Oct 8;461(7265):762-7. doi: 10.1038/nature08398. Epub 2009 Sep 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute and Department of Biochemistry, New York University Medical School, 522 First Avenue, New York, New York 10016, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19767730" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Animals ; Cell Line ; Chromatin/chemistry/*genetics/metabolism ; Crystallography, X-Ray ; Drosophila Proteins/chemistry/genetics/*metabolism ; Drosophila melanogaster/*genetics/growth & development/*metabolism ; Enzyme Activation ; *Gene Silencing ; Histone-Lysine N-Methyltransferase/chemistry/metabolism ; Histones/*chemistry/*metabolism ; Lysine/analogs & derivatives/metabolism ; Methylation ; Models, Biological ; Models, Molecular ; Nuclear Proteins/metabolism ; Nucleosomes/chemistry/genetics/metabolism ; Polycomb Repressive Complex 2 ; Protein Binding ; Protein Structure, Tertiary ; Repressor Proteins/chemistry/genetics/*metabolism ; Substrate Specificity
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  • 45
    Publication Date: 2009-04-14
    Description: In microorganisms, noise in gene expression gives rise to cell-to-cell variability in protein concentrations. In mammalian cells, protein levels also vary and individual cells differ widely in their responsiveness to uniform physiological stimuli. In the case of apoptosis mediated by TRAIL (tumour necrosis factor (TNF)-related apoptosis-inducing ligand) it is common for some cells in a clonal population to die while others survive-a striking divergence in cell fate. Among cells that die, the time between TRAIL exposure and caspase activation is highly variable. Here we image sister cells expressing reporters of caspase activation and mitochondrial outer membrane permeabilization after exposure to TRAIL. We show that naturally occurring differences in the levels or states of proteins regulating receptor-mediated apoptosis are the primary causes of cell-to-cell variability in the timing and probability of death in human cell lines. Protein state is transmitted from mother to daughter, giving rise to transient heritability in fate, but protein synthesis promotes rapid divergence so that sister cells soon become no more similar to each other than pairs of cells chosen at random. Our results have implications for understanding 'fractional killing' of tumour cells after exposure to chemotherapy, and for variability in mammalian signal transduction in general.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858974/" 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/PMC2858974/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Spencer, Sabrina L -- Gaudet, Suzanne -- Albeck, John G -- Burke, John M -- Sorger, Peter K -- CA112967/CA/NCI NIH HHS/ -- GM68762/GM/NIGMS NIH HHS/ -- P50 GM068762/GM/NIGMS NIH HHS/ -- P50 GM068762-06/GM/NIGMS NIH HHS/ -- U54 CA112967/CA/NCI NIH HHS/ -- U54 CA112967-05/CA/NCI NIH HHS/ -- England -- Nature. 2009 May 21;459(7245):428-32. doi: 10.1038/nature08012. Epub 2009 Apr 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Cell Decision Processes, Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19363473" target="_blank"〉PubMed〈/a〉
    Keywords: Apoptosis/*physiology ; BH3 Interacting Domain Death Agonist Protein/metabolism ; Caspases/metabolism ; Cell Division ; Cell Line ; Enzyme Activation ; Fluorescence Resonance Energy Transfer ; Genes, Reporter ; HeLa Cells ; Humans ; Mitochondrial Membranes/metabolism ; Models, Biological ; Permeability ; Probability ; Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism ; Signal Transduction ; TNF-Related Apoptosis-Inducing Ligand/*metabolism ; Time Factors
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  • 46
    Publication Date: 2009-12-17
    Description: How living systems detect the presence of genotoxic damage embedded in a million-fold excess of undamaged DNA is an unresolved question in biology. Here we have captured and structurally elucidated a base-excision DNA repair enzyme, MutM, at the stage of initial encounter with a damaged nucleobase, 8-oxoguanine (oxoG), nested within a DNA duplex. Three structures of intrahelical oxoG-encounter complexes are compared with sequence-matched structures containing a normal G base in place of an oxoG lesion. Although the protein-DNA interfaces in the matched complexes differ by only two atoms-those that distinguish oxoG from G-their pronounced structural differences indicate that MutM can detect a lesion in DNA even at the earliest stages of encounter. All-atom computer simulations show the pathway by which encounter of the enzyme with the lesion causes extrusion from the DNA duplex, and they elucidate the critical free energy difference between oxoG and G along the extrusion pathway.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951314/" 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/PMC2951314/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Qi, Yan -- Spong, Marie C -- Nam, Kwangho -- Banerjee, Anirban -- Jiralerspong, Sao -- Karplus, Martin -- Verdine, Gregory L -- CA100742/CA/NCI NIH HHS/ -- GM030804/GM/NIGMS NIH HHS/ -- GM044853/GM/NIGMS NIH HHS/ -- GM047467/GM/NIGMS NIH HHS/ -- P01 GM047467/GM/NIGMS NIH HHS/ -- P01 GM047467-100006/GM/NIGMS NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 CA100742/CA/NCI NIH HHS/ -- R01 CA100742-06A1/CA/NCI NIH HHS/ -- R01 GM044853/GM/NIGMS NIH HHS/ -- R01 GM044853-18/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2009 Dec 10;462(7274):762-6. doi: 10.1038/nature08561.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Program in Biophysics, Harvard Medical School, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20010681" target="_blank"〉PubMed〈/a〉
    Keywords: Biocatalysis ; Computer Simulation ; Crystallography, X-Ray ; *DNA Damage ; *DNA Repair ; DNA-Formamidopyrimidine Glycosylase/genetics/*metabolism ; Genome, Bacterial/genetics ; Geobacillus stearothermophilus/*enzymology/genetics ; Guanine/*analogs & derivatives/metabolism ; Models, Biological ; Models, Molecular ; Molecular Dynamics Simulation ; Mutation/genetics ; Thermodynamics
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  • 47
    Publication Date: 2009-05-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wolpert, Lewis -- England -- Nature. 2009 May 28;459(7246):506. doi: 10.1038/459506a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19478764" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Cognition/*physiology ; Human Characteristics ; Humans ; Models, Biological
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  • 48
    Publication Date: 2009-10-02
    Description: The discovery of ammonia oxidation by mesophilic and thermophilic Crenarchaeota and the widespread distribution of these organisms in marine and terrestrial environments indicated an important role for them in the global nitrogen cycle. However, very little is known about their physiology or their contribution to nitrification. Here we report oligotrophic ammonia oxidation kinetics and cellular characteristics of the mesophilic crenarchaeon 'Candidatus Nitrosopumilus maritimus' strain SCM1. Unlike characterized ammonia-oxidizing bacteria, SCM1 is adapted to life under extreme nutrient limitation, sustaining high specific oxidation rates at ammonium concentrations found in open oceans. Its half-saturation constant (K(m) = 133 nM total ammonium) and substrate threshold (〈or=10 nM) closely resemble kinetics of in situ nitrification in marine systems and directly link ammonia-oxidizing Archaea to oligotrophic nitrification. The remarkably high specific affinity for reduced nitrogen (68,700 l per g cells per h) of SCM1 suggests that Nitrosopumilus-like ammonia-oxidizing Archaea could successfully compete with heterotrophic bacterioplankton and phytoplankton. Together these findings support the hypothesis that nitrification is more prevalent in the marine nitrogen cycle than accounted for in current biogeochemical models.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Martens-Habbena, Willm -- Berube, Paul M -- Urakawa, Hidetoshi -- de la Torre, Jose R -- Stahl, David A -- England -- Nature. 2009 Oct 15;461(7266):976-9. doi: 10.1038/nature08465. Epub 2009 Sep 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Civil & Environmental Engineering, University of Washington, Seattle, Washington 98105, USA. willmmh@u.washington.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19794413" target="_blank"〉PubMed〈/a〉
    Keywords: Ammonia/*chemistry/*metabolism ; Archaea/*metabolism ; Bacteria/*metabolism ; Kinetics ; Models, Biological ; Nitrogen/metabolism ; Nitrosomonas/metabolism ; Oxidation-Reduction ; Plankton/metabolism ; Quaternary Ammonium Compounds/metabolism ; Seawater/chemistry
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  • 49
    Publication Date: 2009-12-10
    Description: Both biosociological and psychological models, as well as animal research, suggest that testosterone has a key role in social interactions. Evidence from animal studies in rodents shows that testosterone causes aggressive behaviour towards conspecifics. Folk wisdom generalizes and adapts these findings to humans, suggesting that testosterone induces antisocial, egoistic, or even aggressive human behaviours. However, many researchers have questioned this folk hypothesis, arguing that testosterone is primarily involved in status-related behaviours in challenging social interactions, but causal evidence that discriminates between these views is sparse. Here we show that the sublingual administration of a single dose of testosterone in women causes a substantial increase in fair bargaining behaviour, thereby reducing bargaining conflicts and increasing the efficiency of social interactions. However, subjects who believed that they received testosterone-regardless of whether they actually received it or not-behaved much more unfairly than those who believed that they were treated with placebo. Thus, the folk hypothesis seems to generate a strong negative association between subjects' beliefs and the fairness of their offers, even though testosterone administration actually causes a substantial increase in the frequency of fair bargaining offers in our experiment.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Eisenegger, C -- Naef, M -- Snozzi, R -- Heinrichs, M -- Fehr, E -- England -- Nature. 2010 Jan 21;463(7279):356-9. doi: 10.1038/nature08711.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Empirical Research in Economics, Laboratory for Social and Neural Systems Research, University of Zurich, 8006 Zurich, Switzerland. eisenegger@iew.uzh.ch〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19997098" target="_blank"〉PubMed〈/a〉
    Keywords: Administration, Sublingual ; Adult ; Aggression/drug effects/physiology/psychology ; Cooperative Behavior ; Double-Blind Method ; Female ; *Game Theory ; Humans ; Models, Biological ; Placebos ; *Prejudice ; Reproducibility of Results ; *Social Behavior ; Social Class ; Testosterone/administration & dosage/*pharmacology
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  • 50
    Publication Date: 2009-12-18
    Description: It is generally assumed that sister chromatids are genetically and functionally identical and that segregation to daughter cells is a random process. However, functional differences between sister chromatids regulate daughter cell fate in yeast and sister chromatid segregation is not random in Escherichia coli. Differentiated sister chromatids, coupled with non-random segregation, have been proposed to regulate cell fate during the development of multicellular organisms. This hypothesis has not been tested because molecular features to reliably distinguish between sister chromatids are not obvious. Here we show that parental 'Watson' and 'Crick' DNA template strands can be identified in sister chromatids of murine metaphase chromosomes using CO-FISH (chromosome orientation fluorescence in situ hybridization) with unidirectional probes specific for centromeric and telomeric repeats. All chromosomes were found to have a uniform orientation with the 5' end of the short arm on the same strand as T-rich major satellite repeats. The invariable orientation of repetitive DNA was used to differentially label sister chromatids and directly study mitotic segregation patterns in different cell types. Whereas sister chromatids appeared to be randomly distributed between daughter cells in cultured lung fibroblasts and embryonic stem cells, significant non-random sister chromatid segregation was observed in a subset of colon crypt epithelial cells, including cells outside positions reported for colon stem cells. Our results establish that DNA template sequences can be used to distinguish sister chromatids and follow their mitotic segregation in vivo.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3757939/" 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/PMC3757939/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Falconer, Ester -- Chavez, Elizabeth A -- Henderson, Alexander -- Poon, Steven S S -- McKinney, Steven -- Brown, Lindsay -- Huntsman, David G -- Lansdorp, Peter M -- R01 GM094146/GM/NIGMS NIH HHS/ -- RMF-92093/Canadian Institutes of Health Research/Canada -- England -- Nature. 2010 Jan 7;463(7277):93-7. doi: 10.1038/nature08644. Epub 2009 Dec 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Terry Fox Laboratory, B.C. Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016487" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Chromatids/*genetics/*metabolism ; Chromosome Segregation/*physiology ; Colon/cytology ; DNA, Satellite/metabolism ; Embryonic Stem Cells/cytology ; Epithelial Cells/cytology ; Fibroblasts/cytology ; Fluorescence ; In Situ Hybridization, Fluorescence/*methods ; Luminescent Measurements ; Lung/cytology ; Mice ; Mice, Inbred C57BL ; Mitosis ; Models, Biological ; Organ Specificity ; Substrate Specificity ; Telomere/metabolism ; Templates, Genetic
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  • 51
    Publication Date: 2009-06-23
    Description: The pace of Late Triassic (LT) biodiversity loss is uncertain, yet it could help to decipher causal mechanisms of mass extinction. We investigated relative abundance distributions (RADs) of six LT plant assemblages from the Kap Stewart Group, East Greenland, to determine the pace of collapse of LT primary productivity. RADs displayed not simply decreases in the number of taxa, but decreases in the number of common taxa. Likelihood tests rejected a hypothesis of continuously declining diversity. Instead, the RAD shift occurred over the upper two-to-four fossil plant assemblages and most likely over the last three (final 13 meters), coinciding with increased atmospheric carbon dioxide concentration and global warming. Thus, although the LT event did not induce mass extinction of plant families, it accompanied major and abrupt change in their ecology and diversity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McElwain, Jennifer C -- Wagner, Peter J -- Hesselbo, Stephen P -- New York, N.Y. -- Science. 2009 Jun 19;324(5934):1554-6. doi: 10.1126/science.1171706.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉UCD School of Biology and Environmental Science, University College Dublin, National University of Ireland, Belfield, Dublin 4, Ireland. jennifer.mcelwain@ucd.ie〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19541995" target="_blank"〉PubMed〈/a〉
    Keywords: *Biodiversity ; Biological Evolution ; *Extinction, Biological ; *Fossils ; Greenland ; Likelihood Functions ; Models, Biological ; *Plants/genetics
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    Electronic ISSN: 1095-9203
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  • 52
    Publication Date: 2009-04-11
    Description: The nuclear factor kappaB (NF-kappaB) transcription factor regulates cellular stress responses and the immune response to infection. NF-kappaB activation results in oscillations in nuclear NF-kappaB abundance. To define the function of these oscillations, we treated cells with repeated short pulses of tumor necrosis factor-alpha at various intervals to mimic pulsatile inflammatory signals. At all pulse intervals that were analyzed, we observed synchronous cycles of NF-kappaB nuclear translocation. Lower frequency stimulations gave repeated full-amplitude translocations, whereas higher frequency pulses gave reduced translocation, indicating a failure to reset. Deterministic and stochastic mathematical models predicted how negative feedback loops regulate both the resetting of the system and cellular heterogeneity. Altering the stimulation intervals gave different patterns of NF-kappaB-dependent gene expression, which supports the idea that oscillation frequency has a functional role.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785900/" 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/PMC2785900/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ashall, Louise -- Horton, Caroline A -- Nelson, David E -- Paszek, Pawel -- Harper, Claire V -- Sillitoe, Kate -- Ryan, Sheila -- Spiller, David G -- Unitt, John F -- Broomhead, David S -- Kell, Douglas B -- Rand, David A -- See, Violaine -- White, Michael R H -- BB/C007158/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/C008219/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/C520471/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/D010748/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/E004210/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/E012965/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BB/F005938/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- BBC0071581/Biotechnology and Biological Sciences Research Council/United Kingdom -- BBC0082191/Biotechnology and Biological Sciences Research Council/United Kingdom -- BBC5204711/Biotechnology and Biological Sciences Research Council/United Kingdom -- BBD0107481/Biotechnology and Biological Sciences Research Council/United Kingdom -- BBF0059381/Biotechnology and Biological Sciences Research Council/United Kingdom -- G0500346/Medical Research Council/United Kingdom -- G0500346(73596)/Medical Research Council/United Kingdom -- New York, N.Y. -- Science. 2009 Apr 10;324(5924):242-6. doi: 10.1126/science.1164860.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool, L69 7ZB, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19359585" target="_blank"〉PubMed〈/a〉
    Keywords: Active Transport, Cell Nucleus ; Animals ; Cell Line ; Cell Line, Tumor ; Cell Nucleus/metabolism ; Cytoplasm/metabolism ; Feedback, Physiological ; *Gene Expression ; Humans ; I-kappa B Proteins/metabolism ; Mice ; Models, Biological ; Models, Statistical ; NF-kappa B/*metabolism ; Phosphorylation ; Recombinant Fusion Proteins/metabolism ; Stochastic Processes ; Transcription Factor RelA/*metabolism ; *Transcription, Genetic ; Transfection ; Tumor Necrosis Factor-alpha/*metabolism
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  • 53
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-03-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sheps, Jonathan A -- New York, N.Y. -- Science. 2009 Mar 27;323(5922):1679-80. doi: 10.1126/science.1172428.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cancer Genetics and Developmental Biology, BC Cancer Research Centre, British Columbia Cancer Agency, Vancouver, BC V5Z 1L3 Canada. jsheps@bccrc.ca〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19325102" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Biological Transport ; Crystallography, X-Ray ; Drug Design ; Lipid Bilayers/chemistry ; Models, Biological ; Oligopeptides/chemistry/metabolism ; P-Glycoprotein/*chemistry/*metabolism ; Peptides, Cyclic/*chemistry/*metabolism ; Protein Binding ; Protein Conformation ; Stereoisomerism
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  • 54
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-08-22
    Description: Actin filaments and microtubules polymerize and depolymerize by adding and removing subunits at polymer ends, and these dynamics drive cytoplasmic organization, cell division, and cell motility. Since Wegner proposed the treadmilling theory for actin in 1976, it has largely been assumed that the chemical state of the bound nucleotide determines the rates of subunit addition and removal. This chemical kinetics view is difficult to reconcile with observations revealing multiple structural states of the polymer that influence polymerization dynamics but that are not strictly coupled to the bound nucleotide state. We refer to these phenomena as "structural plasticity" and discuss emerging evidence that they play a central role in polymer dynamics and function.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864651/" 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/PMC2864651/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kueh, Hao Yuan -- Mitchison, Timothy J -- GM 23928/GM/NIGMS NIH HHS/ -- R01 GM023928/GM/NIGMS NIH HHS/ -- R01 GM023928-31/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2009 Aug 21;325(5943):960-3. doi: 10.1126/science.1168823.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Systems Biology, Harvard Medical School, Boston, MA 02215, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19696342" target="_blank"〉PubMed〈/a〉
    Keywords: Actin Cytoskeleton/*chemistry/metabolism/ultrastructure ; Actin Depolymerizing Factors/metabolism ; Actins/*chemistry/metabolism ; Adenosine Triphosphate/metabolism ; Guanosine Diphosphate/metabolism ; Guanosine Triphosphate/metabolism ; Kinetics ; Microfilament Proteins/metabolism ; Microtubules/*chemistry/metabolism/ultrastructure ; Models, Biological ; Tubulin/*chemistry/metabolism
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  • 55
    Publication Date: 2009-12-08
    Description: The genome of Mycoplasma pneumoniae is among the smallest found in self-replicating organisms. To study the basic principles of bacterial proteome organization, we used tandem affinity purification-mass spectrometry (TAP-MS) in a proteome-wide screen. The analysis revealed 62 homomultimeric and 116 heteromultimeric soluble protein complexes, of which the majority are novel. About a third of the heteromultimeric complexes show higher levels of proteome organization, including assembly into larger, multiprotein complex entities, suggesting sequential steps in biological processes, and extensive sharing of components, implying protein multifunctionality. Incorporation of structural models for 484 proteins, single-particle electron microscopy, and cellular electron tomograms provided supporting structural details for this proteome organization. The data set provides a blueprint of the minimal cellular machinery required for life.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kuhner, Sebastian -- van Noort, Vera -- Betts, Matthew J -- Leo-Macias, Alejandra -- Batisse, Claire -- Rode, Michaela -- Yamada, Takuji -- Maier, Tobias -- Bader, Samuel -- Beltran-Alvarez, Pedro -- Castano-Diez, Daniel -- Chen, Wei-Hua -- Devos, Damien -- Guell, Marc -- Norambuena, Tomas -- Racke, Ines -- Rybin, Vladimir -- Schmidt, Alexander -- Yus, Eva -- Aebersold, Ruedi -- Herrmann, Richard -- Bottcher, Bettina -- Frangakis, Achilleas S -- Russell, Robert B -- Serrano, Luis -- Bork, Peer -- Gavin, Anne-Claude -- New York, N.Y. -- Science. 2009 Nov 27;326(5957):1235-40. doi: 10.1126/science.1176343.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965468" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*analysis/isolation & purification/metabolism ; Computational Biology ; *Genome, Bacterial ; Mass Spectrometry/methods ; Metabolic Networks and Pathways ; Microscopy, Electron ; Models, Biological ; Models, Molecular ; Multiprotein Complexes/*analysis/metabolism ; Mycoplasma pneumoniae/*chemistry/*genetics/metabolism/ultrastructure ; Pattern Recognition, Automated ; Protein Interaction Mapping ; *Proteome ; Systems Biology
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  • 56
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-08-15
    Description: Dynamin-related proteins (DRPs) can generate forces to remodel membranes. In cells, DRPs require additional proteins [DRP-associated proteins (DAPs)] to conduct their functions. To dissect the mechanistic role of a DAP, we used the yeast mitochondrial division machine as a model, which requires the DRP Dnm1, and two other proteins, Mdv1 and Fis1. Mdv1 played a postmitochondrial targeting role in division by specifically interacting and coassembling with the guanosine triphosphate-bound form of Dnm1. This regulated interaction nucleated and promoted the self-assembly of Dnm1 into helical structures, which drive membrane scission. The nucleation of DRP assembly probably represents a general regulatory strategy for this family of filament-forming proteins, similar to F-actin regulation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lackner, Laura L -- Horner, Jennifer S -- Nunnari, Jodi -- 1F32GM078749/GM/NIGMS NIH HHS/ -- R01 GM062942/GM/NIGMS NIH HHS/ -- R01GM062942/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2009 Aug 14;325(5942):874-7. doi: 10.1126/science.1176921.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19679814" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptor Proteins, Signal Transducing/*metabolism ; GTP Phosphohydrolases/chemistry/genetics/*metabolism ; Guanosine Triphosphate/analogs & derivatives/metabolism ; Intracellular Membranes/physiology ; Kinetics ; Liposomes/metabolism ; Mitochondria/*physiology ; Mitochondrial Proteins/chemistry/genetics/*metabolism ; Models, Biological ; Protein Binding ; Protein Conformation ; Protein Structure, Secondary ; Saccharomyces cerevisiae Proteins/chemistry/genetics/*metabolism
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  • 57
    Publication Date: 2009-09-05
    Description: Hou et al. (Reports, 31 October 2008, p. 736) presented a model for energy uptake and allocation over an organism's growth and development. However, their model does not account for allocation to reproduction (essential to adults) and growth without assimilation (essential to embryos) and is therefore only applicable to organisms growing with abundant food in the juvenile stage.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sousa, Tania -- Marques, Goncalo M -- Domingos, Tiago -- New York, N.Y. -- Science. 2009 Sep 4;325(5945):1206; author reply 1206. doi: 10.1126/science.1169523.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Environment and Energy Section, DEM, and IN+ Center for Innovation Technology and Policy Research, Instituto Superior Tecnico, Lisboa, Portugal.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19729640" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Basal Metabolism ; Biomass ; Birds/embryology/growth & development/*metabolism ; Embryo, Mammalian/metabolism ; Embryo, Nonmammalian/metabolism ; Embryonic Development ; Energy Intake ; *Energy Metabolism ; Food ; *Growth ; Mammals/embryology/growth & development/*metabolism ; Models, Biological ; Oxygen Consumption ; Reproduction
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  • 58
    Publication Date: 2009-09-19
    Description: Insect wings are complex structures that deform dramatically in flight. We analyzed the aerodynamic consequences of wing deformation in locusts using a three-dimensional computational fluid dynamics simulation based on detailed wing kinematics. We validated the simulation against smoke visualizations and digital particle image velocimetry on real locusts. We then used the validated model to explore the effects of wing topography and deformation, first by removing camber while keeping the same time-varying twist distribution, and second by removing camber and spanwise twist. The full-fidelity model achieved greater power economy than the uncambered model, which performed better than the untwisted model, showing that the details of insect wing topography and deformation are important aerodynamically. Such details are likely to be important in engineering applications of flapping flight.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Young, John -- Walker, Simon M -- Bomphrey, Richard J -- Taylor, Graham K -- Thomas, Adrian L R -- 204513/European Research Council/International -- New York, N.Y. -- Science. 2009 Sep 18;325(5947):1549-52. doi: 10.1126/science.1175928.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Engineering and Information Technology, University of New South Wales, Australian Defence Force Academy, Canberra, Australian Capital Territory 2600, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19762645" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biomechanical Phenomena ; Computer Simulation ; Flight, Animal/*physiology ; Grasshoppers/*anatomy & histology/*physiology ; Models, Biological ; Movement ; Wings, Animal/*anatomy & histology/*physiology
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  • 59
    Publication Date: 2009-02-07
    Description: Evolution may be dominated by biotic factors, as in the Red Queen model, or abiotic factors, as in the Court Jester model, or a mixture of both. The two models appear to operate predominantly over different geographic and temporal scales: Competition, predation, and other biotic factors shape ecosystems locally and over short time spans, but extrinsic factors such as climate and oceanographic and tectonic events shape larger-scale patterns regionally and globally, and through thousands and millions of years. Paleobiological studies suggest that species diversity is driven largely by abiotic factors such as climate, landscape, or food supply, and comparative phylogenetic approaches offer new insights into clade dynamics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benton, Michael J -- New York, N.Y. -- Science. 2009 Feb 6;323(5915):728-32. doi: 10.1126/science.1157719.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK. mike.benton@bristol.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19197051" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biodiversity ; *Biological Evolution ; Climate ; Fossils ; *Genetic Speciation ; Geography ; Geological Phenomena ; Logistic Models ; Models, Biological ; Phylogeny ; Time
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  • 60
    Publication Date: 2009-08-01
    Description: After a long history of overexploitation, increasing efforts to restore marine ecosystems and rebuild fisheries are under way. Here, we analyze current trends from a fisheries and conservation perspective. In 5 of 10 well-studied ecosystems, the average exploitation rate has recently declined and is now at or below the rate predicted to achieve maximum sustainable yield for seven systems. Yet 63% of assessed fish stocks worldwide still require rebuilding, and even lower exploitation rates are needed to reverse the collapse of vulnerable species. Combined fisheries and conservation objectives can be achieved by merging diverse management actions, including catch restrictions, gear modification, and closed areas, depending on local context. Impacts of international fleets and the lack of alternatives to fishing complicate prospects for rebuilding fisheries in many poorer regions, highlighting the need for a global perspective on rebuilding marine resources.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Worm, Boris -- Hilborn, Ray -- Baum, Julia K -- Branch, Trevor A -- Collie, Jeremy S -- Costello, Christopher -- Fogarty, Michael J -- Fulton, Elizabeth A -- Hutchings, Jeffrey A -- Jennings, Simon -- Jensen, Olaf P -- Lotze, Heike K -- Mace, Pamela M -- McClanahan, Tim R -- Minto, Coilin -- Palumbi, Stephen R -- Parma, Ana M -- Ricard, Daniel -- Rosenberg, Andrew A -- Watson, Reg -- Zeller, Dirk -- New York, N.Y. -- Science. 2009 Jul 31;325(5940):578-85. doi: 10.1126/science.1173146.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biology Department, Dalhousie University, Halifax, NS B3H 4J1, Canada. bworm@dal.ca〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19644114" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biodiversity ; Biomass ; *Conservation of Natural Resources ; *Ecosystem ; *Fisheries/methods ; *Fishes/anatomy & histology ; Internationality ; Marine Biology ; Models, Biological ; Oceans and Seas ; Population Dynamics
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  • 61
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-01-31
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stevenson, P A -- New York, N.Y. -- Science. 2009 Jan 30;323(5914):594-5. doi: 10.1126/science.1169280.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Biology II, Faculty for Biosciences, Psychology and Pharmacology, Leipzig University, Talstrasse 33, 04103 Leipzig, Germany. stevenson@rz.unileipzig.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19179520" target="_blank"〉PubMed〈/a〉
    Keywords: Animal Migration ; Animals ; *Behavior, Animal ; Crowding ; *Flight, Animal ; Grasshoppers/anatomy & histology/*physiology ; Models, Biological ; Nervous System Physiological Phenomena ; Population Density ; Serotonin/*physiology ; Social Behavior
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  • 62
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-12-08
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stewart, Murray -- Wellcome Trust/United Kingdom -- New York, N.Y. -- Science. 2009 Nov 27;326(5957):1195-6. doi: 10.1126/science.1183273.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK. ms@mrc-lmb.cam.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965455" target="_blank"〉PubMed〈/a〉
    Keywords: Active Transport, Cell Nucleus ; Cell Nucleus/*metabolism ; Cytoplasm/metabolism ; Karyopherins/chemistry/metabolism ; MicroRNAs/chemistry/*metabolism ; Models, Biological ; Nuclear Pore/metabolism ; Nucleic Acid Conformation ; RNA Processing, Post-Transcriptional ; RNA, Small Nuclear/chemistry/*metabolism ; RNA, Transfer/chemistry/*metabolism ; Receptors, Cytoplasmic and Nuclear/chemistry/metabolism ; ran GTP-Binding Protein/metabolism
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  • 63
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-02-07
    Description: Biologists have long been fascinated by the exceptionally high diversity displayed by some evolutionary groups. Adaptive radiation in such clades is not only spectacular, but is also an extremely complex process influenced by a variety of ecological, genetic, and developmental factors and strongly dependent on historical contingencies. Using modeling approaches, we identify 10 general patterns concerning the temporal, spatial, and genetic/morphological properties of adaptive radiation. Some of these are strongly supported by empirical work, whereas for others, empirical support is more tentative. In almost all cases, more data are needed. Future progress in our understanding of adaptive radiation will be most successful if theoretical and empirical approaches are integrated, as has happened in other areas of evolutionary biology.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gavrilets, Sergey -- Losos, Jonathan B -- GM56693/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2009 Feb 6;323(5915):732-7. doi: 10.1126/science.1157966.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology, National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996, USA. sergey@tiem.utk.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19197052" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Biological ; Animals ; *Biodiversity ; *Biological Evolution ; Ecosystem ; Fossils ; *Genetic Speciation ; Genetic Variation ; Models, Biological ; Phylogeny ; Selection, Genetic
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  • 64
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-12-08
    Description: The extracellular matrix (ECM) and ECM proteins are important in phenomena as diverse as developmental patterning, stem cell niches, cancer, and genetic diseases. The ECM has many effects beyond providing structural support. ECM proteins typically include multiple, independently folded domains whose sequences and arrangement are highly conserved. Some of these domains bind adhesion receptors such as integrins that mediate cell-matrix adhesion and also transduce signals into cells. However, ECM proteins also bind soluble growth factors and regulate their distribution, activation, and presentation to cells. As organized, solid-phase ligands, ECM proteins can integrate complex, multivalent signals to cells in a spatially patterned and regulated fashion. These properties need to be incorporated into considerations of the functions of the ECM.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3536535/" 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/PMC3536535/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hynes, Richard O -- P01 HL066105/HL/NHLBI NIH HHS/ -- R01 CA017007/CA/NCI NIH HHS/ -- U54 CA126515/CA/NCI NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2009 Nov 27;326(5957):1216-9. doi: 10.1126/science.1176009.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. rohynes@mit.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965464" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Adhesion ; *Cell Physiological Processes ; Extracellular Matrix/*physiology ; Extracellular Matrix Proteins/chemistry/*metabolism ; Humans ; Intercellular Signaling Peptides and Proteins/metabolism ; Models, Biological ; Protein Binding ; Protein Interaction Domains and Motifs ; Protein Structure, Tertiary ; Signal Transduction ; Transforming Growth Factor beta/metabolism
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  • 65
    Publication Date: 2009-04-25
    Description: Determining proper responsiveness to incoming signals is fundamental to all biological systems. We demonstrate that intracellular signaling nodes can tune a signaling network's response threshold away from the basal median effective concentration established by ligand-receptor interactions. Focusing on the bistable kinase network that governs progesterone-induced meiotic entry in Xenopus oocytes, we characterized glycogen synthase kinase-3beta (GSK-3beta) as a dampener of progesterone responsiveness. GSK-3beta engages the meiotic kinase network through a double-negative feedback loop; this specific feedback architecture raises the progesterone threshold in correspondence with the strength of double-negative signaling. We also identified a marker of nutritional status, l-leucine, which lowers the progesterone threshold, indicating that oocytes integrate additional signals into their cell-fate decisions by modulating progesterone responsiveness.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880456/" 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/PMC2880456/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Justman, Quincey A -- Serber, Zach -- Ferrell, James E Jr -- El-Samad, Hana -- Shokat, Kevan M -- AI49006/AI/NIAID NIH HHS/ -- GM46383/GM/NIGMS NIH HHS/ -- R01 AI044009/AI/NIAID NIH HHS/ -- R01 AI044009-10/AI/NIAID NIH HHS/ -- R01 GM046383/GM/NIGMS NIH HHS/ -- R01 GM046383-19/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2009 Apr 24;324(5926):509-12. doi: 10.1126/science.1169498.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Group in Biophysics, University of California, San Francisco, CA 94158, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19390045" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Enzyme Activation ; Feedback, Physiological ; Glycogen Synthase Kinase 3/*metabolism ; Leucine/metabolism ; *MAP Kinase Signaling System/physiology ; Meiosis/physiology ; Mitogen-Activated Protein Kinases/metabolism ; Models, Biological ; Oocytes/*cytology/*metabolism ; Oogenesis/*physiology ; Phosphorylation ; Progesterone/*physiology ; Xenopus
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  • 66
    Publication Date: 2009-09-19
    Description: Metabolic pathways have traditionally been described in terms of biochemical reactions and metabolites. With the use of structural genomics and systems biology, we generated a three-dimensional reconstruction of the central metabolic network of the bacterium Thermotoga maritima. The network encompassed 478 proteins, of which 120 were determined by experiment and 358 were modeled. Structural analysis revealed that proteins forming the network are dominated by a small number (only 182) of basic shapes (folds) performing diverse but mostly related functions. Most of these folds are already present in the essential core (approximately 30%) of the network, and its expansion by nonessential proteins is achieved with relatively few additional folds. Thus, integration of structural data with networks analysis generates insight into the function, mechanism, and evolution of biological networks.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2833182/" 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/PMC2833182/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Ying -- Thiele, Ines -- Weekes, Dana -- Li, Zhanwen -- Jaroszewski, Lukasz -- Ginalski, Krzysztof -- Deacon, Ashley M -- Wooley, John -- Lesley, Scott A -- Wilson, Ian A -- Palsson, Bernhard -- Osterman, Andrei -- Godzik, Adam -- P20 GM076221/GM/NIGMS NIH HHS/ -- P20 GM076221-03/GM/NIGMS NIH HHS/ -- U54 GM074898/GM/NIGMS NIH HHS/ -- U54 GM074898-05/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2009 Sep 18;325(5947):1544-9. doi: 10.1126/science.1174671.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Joint Center for Molecular Modeling (JCMM), Burnham Institute for Medical Research, La Jolla, CA 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19762644" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/*metabolism ; Computational Biology ; Computer Simulation ; Enzymes/*chemistry/*metabolism ; Evolution, Molecular ; Genes, Bacterial ; Genome, Bacterial ; *Metabolic Networks and Pathways ; Models, Biological ; Models, Molecular ; Protein Conformation ; Protein Folding ; Protein Structure, Tertiary ; Systems Biology ; Thermotoga maritima/chemistry/genetics/*metabolism
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  • 67
    Publication Date: 2009-01-20
    Description: Successful cell division requires that chromosomes attach to opposite poles of the mitotic spindle (bi-orientation). Aurora B kinase regulates chromosome-spindle attachments by phosphorylating kinetochore substrates that bind microtubules. Centromere tension stabilizes bi-oriented attachments, but how physical forces are translated into signaling at individual centromeres is unknown. Using fluorescence resonance energy transfer-based biosensors to measure localized phosphorylation dynamics in living cells, we found that phosphorylation of an Aurora B substrate at the kinetochore depended on its distance from the kinase at the inner centromere. Furthermore, repositioning Aurora B closer to the kinetochore prevented stabilization of bi-oriented attachments and activated the spindle checkpoint. Thus, centromere tension can be sensed by increased spatial separation of Aurora B from kinetochore substrates, which reduces phosphorylation and stabilizes kinetochore microtubules.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2713345/" 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/PMC2713345/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Dan -- Vader, Gerben -- Vromans, Martijn J M -- Lampson, Michael A -- Lens, Susanne M A -- GM083988/GM/NIGMS NIH HHS/ -- R01 GM083988/GM/NIGMS NIH HHS/ -- R01 GM083988-01/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2009 Mar 6;323(5919):1350-3. doi: 10.1126/science.1167000. Epub 2009 Jan 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19150808" target="_blank"〉PubMed〈/a〉
    Keywords: Aurora Kinase B ; Aurora Kinases ; Autoantigens/metabolism ; Biosensing Techniques ; Cell Line, Tumor ; Centromere/enzymology/*metabolism ; Chromatids/metabolism ; Chromosomal Proteins, Non-Histone/metabolism ; Chromosomes, Human/*metabolism ; Fluorescence Resonance Energy Transfer ; HeLa Cells ; Humans ; Kinetochores/*metabolism ; Microtubules/*metabolism ; Mitosis ; Models, Biological ; Phosphorylation ; Protein-Serine-Threonine Kinases/*metabolism ; Recombinant Fusion Proteins/metabolism ; Spindle Apparatus/*metabolism
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 68
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-06-27
    Description: The investigation and study of cancer stem cells (CSCs) have received enormous attention over the past 5 to 10 years but remain topics of considerable controversy. Opinions about the validity of the CSC hypothesis, the biological properties of CSCs, and the relevance of CSCs to cancer therapy differ widely. In the following commentary, we discuss the nature of the debate, the parameters by which CSCs can or cannot be defined, and the identification of new potential therapeutic targets elucidated by considering cancer as a problem in stem cell biology.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873047/" 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/PMC2873047/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rosen, Jeffrey M -- Jordan, Craig T -- R01 CA122206/CA/NCI NIH HHS/ -- R01 CA122206-02/CA/NCI NIH HHS/ -- R01-CA122206/CA/NCI NIH HHS/ -- R37 CA016303/CA/NCI NIH HHS/ -- R37 CA016303-36/CA/NCI NIH HHS/ -- R37-CA16303/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2009 Jun 26;324(5935):1670-3. doi: 10.1126/science.1171837.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19556499" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Humans ; Mice ; Models, Biological ; Neoplasm Transplantation ; Neoplasms/genetics/metabolism/*pathology/therapy ; Neoplastic Stem Cells/cytology/*physiology ; Transcription, Genetic
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  • 69
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-04-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tobalske, Bret W -- New York, N.Y. -- Science. 2009 Apr 10;324(5924):190-1. doi: 10.1126/science.1172839.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA. bret.tobalske@mso.umt.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19359571" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biomechanical Phenomena ; Birds/anatomy & histology/*physiology ; Body Size ; Chiroptera/anatomy & histology/*physiology ; Flight, Animal/*physiology ; Insects/anatomy & histology/*physiology ; Models, Biological ; Motion ; Movement ; Nervous System Physiological Phenomena ; Rotation ; Torque ; Wings, Animal/anatomy & histology/*physiology
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  • 70
    Publication Date: 2009-12-08
    Description: The thiol group of the amino acid cysteine can be modified to regulate protein activity. The Escherichia coli periplasm is an oxidizing environment in which most cysteine residues are involved in disulfide bonds. However, many periplasmic proteins contain single cysteine residues, which are vulnerable to oxidation to sulfenic acids and then irreversibly modified to sulfinic and sulfonic acids. We discovered that DsbG and DsbC, two thioredoxin-related proteins, control the global sulfenic acid content of the periplasm and protect single cysteine residues from oxidation. DsbG interacts with the YbiS protein and, along with DsbC, regulates oxidation of its catalytic cysteine residue. Thus, a potentially widespread mechanism controls sulfenic acid modification in the cellular environment.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Depuydt, Matthieu -- Leonard, Stephen E -- Vertommen, Didier -- Denoncin, Katleen -- Morsomme, Pierre -- Wahni, Khadija -- Messens, Joris -- Carroll, Kate S -- Collet, Jean-Francois -- New York, N.Y. -- Science. 2009 Nov 20;326(5956):1109-11. doi: 10.1126/science.1179557.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉de Duve Institute, Universite catholique de Louvain, B-1200 Brussels, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965429" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Catalytic Domain ; Cysteine/chemistry/*metabolism ; Disulfides/chemistry/metabolism ; Escherichia coli/genetics/*metabolism ; Escherichia coli Proteins/chemistry/genetics/*metabolism ; Models, Biological ; Molecular Sequence Data ; Oxidation-Reduction ; Oxidoreductases/chemistry/genetics/*metabolism ; Periplasm/*metabolism ; Periplasmic Proteins/chemistry/genetics/*metabolism ; Protein Binding ; Protein Disulfide-Isomerases/chemistry/genetics/*metabolism ; Proteomics ; Substrate Specificity ; Sulfenic Acids/metabolism
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  • 71
    Publication Date: 2009-01-24
    Description: Regeneration of injured neurons can restore function, but most neurons regenerate poorly or not at all. The failure to regenerate in some cases is due to a lack of activation of cell-intrinsic regeneration pathways. These pathways might be targeted for the development of therapies that can restore neuron function after injury or disease. Here, we show that the DLK-1 mitogen-activated protein (MAP) kinase pathway is essential for regeneration in Caenorhabditis elegans motor neurons. Loss of this pathway eliminates regeneration, whereas activating it improves regeneration. Further, these proteins also regulate the later step of growth cone migration. We conclude that after axon injury, activation of this MAP kinase cascade is required to switch the mature neuron from an aplastic state to a state capable of growth.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2729122/" 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/PMC2729122/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hammarlund, Marc -- Nix, Paola -- Hauth, Linda -- Jorgensen, Erik M -- Bastiani, Michael -- 1R21NS060275/NS/NINDS NIH HHS/ -- NS034307/NS/NINDS NIH HHS/ -- R21 NS060275-02/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 2009 Feb 6;323(5915):802-6. doi: 10.1126/science.1165527. Epub 2009 Jan 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19164707" target="_blank"〉PubMed〈/a〉
    Keywords: Aging ; Animals ; Axons/*physiology/ultrastructure ; Axotomy ; Caenorhabditis elegans/genetics/*physiology ; Caenorhabditis elegans Proteins/genetics/*metabolism ; Growth Cones/physiology ; MAP Kinase Kinase 4/genetics/metabolism ; MAP Kinase Kinase Kinases/genetics/*metabolism ; *MAP Kinase Signaling System ; Mitogen-Activated Protein Kinases/genetics/metabolism ; Models, Biological ; Motor Neurons/*physiology ; Mutation ; Nerve Regeneration/physiology ; RNA Interference ; gamma-Aminobutyric Acid/metabolism
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  • 72
    Publication Date: 2009-11-26
    Description: Expression of the Escherichia coli tryptophanase operon depends on ribosome stalling during translation of the upstream TnaC leader peptide, a process for which interactions between the TnaC nascent chain and the ribosomal exit tunnel are critical. We determined a 5.8 angstrom-resolution cryo-electron microscopy and single-particle reconstruction of a ribosome stalled during translation of the tnaC leader gene. The nascent chain was extended within the exit tunnel, making contacts with ribosomal components at distinct sites. Upon stalling, two conserved residues within the peptidyltransferase center adopted conformations that preclude binding of release factors. We propose a model whereby interactions within the tunnel are relayed to the peptidyltransferase center to inhibit translation. Moreover, we show that nascent chains adopt distinct conformations within the ribosomal exit tunnel.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2920484/" 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/PMC2920484/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Seidelt, Birgit -- Innis, C Axel -- Wilson, Daniel N -- Gartmann, Marco -- Armache, Jean-Paul -- Villa, Elizabeth -- Trabuco, Leonardo G -- Becker, Thomas -- Mielke, Thorsten -- Schulten, Klaus -- Steitz, Thomas A -- Beckmann, Roland -- GM022778/GM/NIGMS NIH HHS/ -- P41 RR005969/RR/NCRR NIH HHS/ -- P41 RR005969-19/RR/NCRR NIH HHS/ -- P41-RR05969/RR/NCRR NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2009 Dec 4;326(5958):1412-5. doi: 10.1126/science.1177662. Epub 2009 Oct 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Gene Center and Center for Integrated Protein Science Munich (CIPSM), Department for Chemistry and Biochemistry, University of Munich, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19933110" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Cryoelectron Microscopy ; Escherichia coli/*genetics/metabolism ; Escherichia coli Proteins/*chemistry/genetics/*metabolism/ultrastructure ; Gene Expression Regulation, Bacterial ; Image Processing, Computer-Assisted ; Models, Biological ; Models, Molecular ; Operon ; Peptidyl Transferases/metabolism ; *Protein Biosynthesis ; Protein Conformation ; RNA-Binding Proteins/chemistry/metabolism/ultrastructure ; Ribosomal Proteins/chemistry/metabolism/ultrastructure ; Ribosomes/*metabolism/ultrastructure ; Tryptophanase/biosynthesis/*genetics
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  • 73
    Publication Date: 2009-12-19
    Description: Acute exposure to ionizing radiation can cause lethal damage to the gastrointestinal (GI) tract, a condition called the GI syndrome. Whether the target cells affected by radiation to cause the GI syndrome are derived from the epithelium or endothelium and whether the target cells die by apoptosis or other mechanisms are controversial issues. Studying mouse models, we found that selective deletion of the proapoptotic genes Bak1 and Bax from the GI epithelium or from endothelial cells did not protect mice from developing the GI syndrome after sub-total-body gamma irradiation. In contrast, selective deletion of p53 from the GI epithelium, but not from endothelial cells, sensitized irradiated mice to the GI syndrome. Transgenic mice overexpressing p53 in all tissues were protected from the GI syndrome after irradiation. These results suggest that the GI syndrome is caused by the death of GI epithelial cells and that these epithelial cells die by a mechanism that is regulated by p53 but independent of apoptosis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897160/" 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/PMC2897160/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kirsch, David G -- Santiago, Philip M -- di Tomaso, Emmanuelle -- Sullivan, Julie M -- Hou, Wu-Shiun -- Dayton, Talya -- Jeffords, Laura B -- Sodha, Pooja -- Mercer, Kim L -- Cohen, Rhianna -- Takeuchi, Osamu -- Korsmeyer, Stanley J -- Bronson, Roderick T -- Kim, Carla F -- Haigis, Kevin M -- Jain, Rakesh K -- Jacks, Tyler -- K08 CA 114176/CA/NCI NIH HHS/ -- K08 CA114176/CA/NCI NIH HHS/ -- K08 CA114176-05/CA/NCI NIH HHS/ -- P01 CA080124/CA/NCI NIH HHS/ -- P01 CA080124-01A1/CA/NCI NIH HHS/ -- P01 CA80124/CA/NCI NIH HHS/ -- P30 CA014051/CA/NCI NIH HHS/ -- P30 CA014051-38/CA/NCI NIH HHS/ -- P30 DK043351/DK/NIDDK NIH HHS/ -- P30-CA14051/CA/NCI NIH HHS/ -- RC1 AI078521/AI/NIAID NIH HHS/ -- RC1 AI078521-01/AI/NIAID NIH HHS/ -- RC1-AI078521/AI/NIAID NIH HHS/ -- U19-AI06775/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2010 Jan 29;327(5965):593-6. doi: 10.1126/science.1166202. Epub 2009 Dec 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20019247" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Apoptosis ; Cell Death ; Epithelial Cells/cytology/physiology/radiation effects ; Gamma Rays/*adverse effects ; Gene Deletion ; Genes, p53 ; Intestinal Diseases/etiology/pathology/*physiopathology ; Intestinal Mucosa/pathology/physiopathology/*radiation effects ; Intestine, Small/pathology/physiopathology/*radiation effects ; Mesoderm/cytology ; Mice ; Mice, Transgenic ; Models, Biological ; Radiation Dosage ; Radiation Injuries/etiology/pathology/*physiopathology ; Tumor Suppressor Protein p53/*physiology ; bcl-2 Homologous Antagonist-Killer Protein/genetics/metabolism ; bcl-2-Associated X Protein/genetics/metabolism
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  • 74
    Publication Date: 2009-03-07
    Description: How environmental change affects species abundances depends on both the food web within which species interact and their potential to evolve. Using field experiments, we investigated both ecological and evolutionary responses of pea aphids (Acyrthosiphon pisum), a common agricultural pest, to increased frequency of episodic heat shocks. One predator species ameliorated the decrease in aphid population growth with increasing heat shocks, whereas a second predator did not, with this contrast caused by behavioral differences between predators. We also compared aphid strains with stably inherited differences in heat tolerance caused by bacterial endosymbionts and showed the potential for rapid evolution for heat-shock tolerance. Our results illustrate how ecological and evolutionary complexities should be incorporated into predictions of the consequences of environmental change for species' populations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harmon, Jason P -- Moran, Nancy A -- Ives, Anthony R -- New York, N.Y. -- Science. 2009 Mar 6;323(5919):1347-50. doi: 10.1126/science.1167396.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology, University of Wisconsin, Madison, WI 53706, USA. jharmon@wisc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19265021" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aphids/genetics/microbiology/*physiology ; Beetles/*physiology ; Biological Evolution ; Buchnera/genetics/physiology ; *Ecosystem ; *Food Chain ; *Hot Temperature ; Models, Biological ; Population Density ; Population Dynamics ; Population Growth ; Predatory Behavior ; Symbiosis
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  • 75
    Publication Date: 2009-04-11
    Description: Flying animals exhibit remarkable capabilities for both generating maneuvers and stabilizing their course and orientation after perturbation. Here we show that flapping fliers ranging in size from fruit flies to large birds benefit from substantial damping of angular velocity through a passive mechanism termed flapping counter-torque (FCT). Our FCT model predicts that isometrically scaled animals experience similar damping on a per-wingbeat time scale, resulting in similar turning dynamics in wingbeat time regardless of body size. The model also shows how animals may simultaneously specialize in both maneuverability and stability (at the cost of efficiency) and provides a framework for linking morphology, wing kinematics, maneuverability, and flight dynamics across a wide range of flying animals spanning insects, bats, and birds.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hedrick, Tyson L -- Cheng, Bo -- Deng, Xinyan -- New York, N.Y. -- Science. 2009 Apr 10;324(5924):252-5. doi: 10.1126/science.1168431.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. thedrick@bio.unc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19359586" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biomechanical Phenomena ; Birds/anatomy & histology/*physiology ; Body Size ; Chiroptera/anatomy & histology/*physiology ; Flight, Animal ; Insects/anatomy & histology/*physiology ; Mathematical Concepts ; Models, Biological ; Motion ; Movement ; Nervous System Physiological Phenomena ; Rotation ; Torque ; Wings, Animal/anatomy & histology/*physiology
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  • 76
    Publication Date: 2009-02-21
    Description: Embryogenesis depends on self-regulatory interactions between spatially separated signaling centers, but few of these are well understood. Limb development is regulated by epithelial-mesenchymal (e-m) feedback loops between sonic hedgehog (SHH) and fibroblast growth factor (FGF) signaling involving the bone morphogenetic protein (BMP) antagonist Gremlin1 (GREM1). By combining mouse molecular genetics with mathematical modeling, we showed that BMP4 first initiates and SHH then propagates e-m feedback signaling through differential transcriptional regulation of Grem1 to control digit specification. This switch occurs by linking a fast BMP4/GREM1 module to the slower SHH/GREM1/FGF e-m feedback loop. This self-regulatory signaling network results in robust regulation of distal limb development that is able to compensate for variations by interconnectivity among the three signaling pathways.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benazet, Jean-Denis -- Bischofberger, Mirko -- Tiecke, Eva -- Goncalves, Alexandre -- Martin, James F -- Zuniga, Aimee -- Naef, Felix -- Zeller, Rolf -- 2R01DE12324-12/DE/NIDCR NIH HHS/ -- R01DE16329/DE/NIDCR NIH HHS/ -- New York, N.Y. -- Science. 2009 Feb 20;323(5917):1050-3. doi: 10.1126/science.1168755.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Developmental Genetics, Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19229034" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Body Patterning ; Bone Morphogenetic Protein 4/genetics/metabolism ; Epithelium/embryology/metabolism ; *Feedback, Physiological ; Fibroblast Growth Factors/genetics/metabolism ; Forelimb/*embryology ; Hedgehog Proteins/genetics/metabolism ; Intercellular Signaling Peptides and Proteins/genetics/metabolism ; Limb Buds/embryology/metabolism ; Mesoderm/metabolism ; Mice ; Models, Biological ; *Signal Transduction ; Toes/embryology
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  • 77
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-06-27
    Description: Competitive interactions between cells are the basis of many homeostatic processes in biology. Some of the best-described cases of competition between cells occur in Drosophila: cell competition, whereby somatic cells within a growing epithelium compete with one another for contribution to the adult, and stem cell competition, in which germline or somatic stem cells vie for residency in the niche. Both types of competition are conserved physiological processes, with much to tell us about how cellular neighborhoods influence cell behavior, and have importance to stem cell biology, regeneration and transplantation, and cancer.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2736143/" 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/PMC2736143/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Johnston, Laura A -- GMO78464/PHS HHS/ -- HD42770/HD/NICHD NIH HHS/ -- R01 GM078464/GM/NIGMS NIH HHS/ -- R01 GM078464-01/GM/NIGMS NIH HHS/ -- R01 GM078464-02/GM/NIGMS NIH HHS/ -- R01 GM078464-03/GM/NIGMS NIH HHS/ -- R01 HD042770/HD/NICHD NIH HHS/ -- R01 HD042770-02/HD/NICHD NIH HHS/ -- R01 HD042770-03/HD/NICHD NIH HHS/ -- R01 HD042770-04/HD/NICHD NIH HHS/ -- R01 HD042770-05/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 2009 Jun 26;324(5935):1679-82. doi: 10.1126/science.1163862.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. lj180@columbia.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19556501" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Apoptosis ; *Cell Communication ; *Cell Physiological Phenomena ; *Cell Proliferation ; Drosophila/cytology ; Homeostasis ; Models, Biological ; Signal Transduction ; Stem Cell Niche/physiology ; Stem Cells/cytology/*physiology
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  • 78
    Publication Date: 2009-12-17
    Description: Cells have self-organizing properties that control their behavior in complex tissues. Contact between cells expressing either B-type Eph receptors or their transmembrane ephrin ligands initiates bidirectional signals that regulate cell positioning. However, simultaneously investigating how information is processed in two interacting cell types remains a challenge. We implemented a proteomic strategy to systematically determine cell-specific signaling networks underlying EphB2- and ephrin-B1-controlled cell sorting. Quantitative mass spectrometric analysis of mixed populations of EphB2- and ephrin-B1-expressing cells that were labeled with different isotopes revealed cell-specific tyrosine phosphorylation events. Functional associations between these phosphotyrosine signaling networks and cell sorting were established with small interfering RNA screening. Data-driven network modeling revealed that signaling between mixed EphB2- and ephrin-B1-expressing cells is asymmetric and that the distinct cell types use different tyrosine kinases and targets to process signals induced by cell-cell contact. We provide systems- and cell-specific network models of contact-initiated signaling between two distinct cell types.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jorgensen, Claus -- Sherman, Andrew -- Chen, Ginny I -- Pasculescu, Adrian -- Poliakov, Alexei -- Hsiung, Marilyn -- Larsen, Brett -- Wilkinson, David G -- Linding, Rune -- Pawson, Tony -- MC_U117532048/Medical Research Council/United Kingdom -- MOP-6849/Canadian Institutes of Health Research/Canada -- New York, N.Y. -- Science. 2009 Dec 11;326(5959):1502-9. doi: 10.1126/science.1176615.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Samuel Lunenfeld Research Institute (SLRI), Mount Sinai Hospital, Toronto M5G 1X5, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20007894" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptor Proteins, Signal Transducing/metabolism ; Algorithms ; Cell Line ; Ephrin-B1/genetics/*metabolism ; Humans ; Ligands ; Mass Spectrometry ; Models, Biological ; PDZ Domains ; Phosphorylation ; Protein Binding ; Protein Interaction Domains and Motifs ; Protein-Tyrosine Kinases/metabolism ; Proteomics ; RNA, Small Interfering ; Receptor, EphB2/genetics/*metabolism ; *Signal Transduction ; Tyrosine/metabolism ; src Homology Domains
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  • 79
    Publication Date: 2009-02-07
    Description: The Bacteria and Archaea are the most genetically diverse superkingdoms of life, and techniques for exploring that diversity are only just becoming widespread. Taxonomists classify these organisms into species in much the same way as they classify eukaryotes, but differences in their biology-including horizontal gene transfer between distantly related taxa and variable rates of homologous recombination-mean that we still do not understand what a bacterial species is. This is not merely a semantic question; evolutionary theory should be able to explain why species exist at all levels of the tree of life, and we need to be able to define species for practical applications in industry, agriculture, and medicine. Recent studies have emphasized the need to combine genetic diversity and distinct ecology in an attempt to define species in a coherent and convincing fashion. The resulting data may help to discriminate among the many theories of prokaryotic species that have been produced to date.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fraser, Christophe -- Alm, Eric J -- Polz, Martin F -- Spratt, Brian G -- Hanage, William P -- 089472/Wellcome Trust/United Kingdom -- Wellcome Trust/United Kingdom -- New York, N.Y. -- Science. 2009 Feb 6;323(5915):741-6. doi: 10.1126/science.1159388.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK. c.fraser@imperial.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19197054" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteria/*classification/*genetics ; *Biodiversity ; Biological Evolution ; *Ecosystem ; Extinction, Biological ; Genes, Bacterial ; *Genetic Speciation ; *Genetic Variation ; Models, Biological ; Models, Genetic ; Recombination, Genetic ; Selection, Genetic
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  • 80
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-06-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zimmer, Carl -- New York, N.Y. -- Science. 2009 Jun 5;324(5932):1254-6. doi: 10.1126/science.324_1254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19498143" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Female ; Host-Parasite Interactions ; Humans ; Male ; Mating Preference, Animal ; *Meiosis ; Models, Biological ; Mutation ; Recombination, Genetic ; *Reproduction ; *Sex
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  • 81
    Publication Date: 2009-09-05
    Description: We demonstrate that the model of energy allocation during ontogeny of Hou et al. (Reports, 31 October 2008, p. 736) fails to account for the observed elevation of metabolic rate in growing organisms compared with similarly sized adults of different species. The basic model assumptions of the three-quarter power scaling for resting metabolism and constancy of the mass-specific maintenance metabolism need to be reassessed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Makarieva, Anastassia M -- Gorshkov, Victor G -- Li, Bai-Lian -- New York, N.Y. -- Science. 2009 Sep 4;325(5945):1206; author reply 1206. doi: 10.1126/science.1171303.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Theoretical Physics Division, Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg, Russia. elba@peterlink.ru〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19729641" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Basal Metabolism ; Birds/growth & development/*metabolism ; Body Weight ; *Energy Metabolism ; *Growth ; Mammals/growth & development/*metabolism ; Models, Biological ; Species Specificity
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  • 82
    Publication Date: 2009-11-26
    Description: The pathogenicity of many bacteria depends on the injection of effector proteins via type III secretion into eukaryotic cells in order to manipulate cellular processes. TAL (transcription activator-like) effectors from plant pathogenic Xanthomonas are important virulence factors that act as transcriptional activators in the plant cell nucleus, where they directly bind to DNA via a central domain of tandem repeats. Here, we show how target DNA specificity of TAL effectors is encoded. Two hypervariable amino acid residues in each repeat recognize one base pair in the target DNA. Recognition sequences of TAL effectors were predicted and experimentally confirmed. The modular protein architecture enabled the construction of artificial effectors with new specificities. Our study describes the functionality of a distinct type of DNA binding domain and allows the design of DNA binding domains for biotechnology.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boch, Jens -- Scholze, Heidi -- Schornack, Sebastian -- Landgraf, Angelika -- Hahn, Simone -- Kay, Sabine -- Lahaye, Thomas -- Nickstadt, Anja -- Bonas, Ulla -- New York, N.Y. -- Science. 2009 Dec 11;326(5959):1509-12. doi: 10.1126/science.1178811. Epub .〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Genetics, Institute of Biology, Martin-Luther-University Halle-Wittenberg, Weinbergweg 10, D-06099 Halle (Saale) Germany. jens.boch@genetik.uni-halle.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19933107" target="_blank"〉PubMed〈/a〉
    Keywords: *Amino Acid Motifs ; Amino Acid Sequence ; Arabidopsis/genetics ; Bacterial Proteins/chemistry/metabolism ; Base Pairing ; Base Sequence ; Biotechnology ; Capsicum/genetics ; DNA, Plant/*chemistry/*metabolism ; DNA-Binding Proteins/*chemistry/*metabolism ; Genes, Plant ; Models, Biological ; Molecular Sequence Data ; Promoter Regions, Genetic ; Protein Binding ; Repetitive Sequences, Amino Acid ; Tobacco/genetics ; Transcription Factors/chemistry/metabolism ; *Transcriptional Activation ; Xanthomonas/*metabolism/pathogenicity
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  • 83
    Publication Date: 2009-12-08
    Description: Signal transduction can be defined as the coordinated relay of messages derived from extracellular cues to intracellular effectors. More simply put, information received on the cell surface is processed across the plasma membrane and transmitted to intracellular targets. This requires that the activators, effectors, enzymes, and substrates that respond to cellular signals come together when they need to.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3041271/" 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/PMC3041271/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scott, John D -- Pawson, Tony -- 57793/Canadian Institutes of Health Research/Canada -- 6849/Canadian Institutes of Health Research/Canada -- GM48231/GM/NIGMS NIH HHS/ -- R37 GM048231/GM/NIGMS NIH HHS/ -- R37 GM048231-19/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2009 Nov 27;326(5957):1220-4. doi: 10.1126/science.1175668.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, Howard Hughes Medical Institute, Box 357750, University of Washington School of Medicine, Seattle, WA 98195, USA. scottjdw@u.washington.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965465" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Compartmentation ; Cell Membrane/*metabolism ; Cell Nucleus/*metabolism ; Cytoplasm/*metabolism ; Enzymes/metabolism ; Humans ; MAP Kinase Signaling System ; Models, Biological ; Multiprotein Complexes/metabolism ; Protein Interaction Domains and Motifs ; Proteins/*metabolism ; *Signal Transduction ; Time Factors ; Transcription, Genetic
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  • 84
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2009-02-07
    Description: Natural selection commonly drives the origin of species, as Darwin initially claimed. Mechanisms of speciation by selection fall into two broad categories: ecological and mutation-order. Under ecological speciation, divergence is driven by divergent natural selection between environments, whereas under mutation-order speciation, divergence occurs when different mutations arise and are fixed in separate populations adapting to similar selection pressures. Tests of parallel evolution of reproductive isolation, trait-based assortative mating, and reproductive isolation by active selection have demonstrated that ecological speciation is a common means by which new species arise. Evidence for mutation-order speciation by natural selection is more limited and has been best documented by instances of reproductive isolation resulting from intragenomic conflict. However, we still have not identified all aspects of selection, and identifying the underlying genes for reproductive isolation remains challenging.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schluter, Dolph -- New York, N.Y. -- Science. 2009 Feb 6;323(5915):737-41. doi: 10.1126/science.1160006.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biodiversity Research Centre and Zoology Department, University of British Columbia, Vancouver, BC V6T 1Z4, Canada. schluter@zoology.ubc.ca〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19197053" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Biological ; Animals ; Biological Evolution ; *Ecosystem ; Genes ; *Genetic Speciation ; Genetic Variation ; Models, Biological ; Models, Genetic ; *Mutation ; Phenotype ; Plants/genetics ; Quantitative Trait Loci ; Reproduction ; *Selection, Genetic
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  • 85
    Publication Date: 2009-07-04
    Description: Environmental change, including climate change, can cause rapid phenotypic change via both ecological and evolutionary processes. Because ecological and evolutionary dynamics are intimately linked, a major challenge is to identify their relative roles. We exactly decomposed the change in mean body weight in a free-living population of Soay sheep into all the processes that contribute to change. Ecological processes contribute most, with selection--the underpinning of adaptive evolution--explaining little of the observed phenotypic trend. Our results enable us to explain why selection has so little effect even though weight is heritable, and why environmental change has caused a decline in the body size of Soay sheep.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ozgul, Arpat -- Tuljapurkar, Shripad -- Benton, Tim G -- Pemberton, Josephine M -- Clutton-Brock, Tim H -- Coulson, Tim -- P01 AG022500/AG/NIA NIH HHS/ -- P01/AG/22500/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 2009 Jul 24;325(5939):464-7. doi: 10.1126/science.1173668. Epub 2009 Jul 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Life Sciences, Imperial College London, Silwood Park, Ascot, Berkshire SL5 7PY, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19574350" target="_blank"〉PubMed〈/a〉
    Keywords: *Adaptation, Biological ; Animals ; *Biological Evolution ; *Body Size ; Body Weight ; Ecosystem ; *Environment ; Female ; Male ; Models, Biological ; Phenotype ; Sheep, Domestic/*anatomy & histology/growth & development
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  • 86
    Publication Date: 2009-06-06
    Description: The female reproductive unit of flowering plants, the haploid female gametophyte, is highly reduced relative to other land plants. We show that patterning of the Arabidopsis female gametophyte depends on an asymmetric distribution of the hormone auxin during its syncitial development. Furthermore, this auxin gradient is correlated with location-specific auxin biosynthesis, rather than auxin efflux that directs patterning in the diploid sporophytic tissues comprising the rest of the plant. Manipulation of auxin responses or synthesis induces switching of gametic and nongametic cell identities and specialized nonreproductive cells to exhibit attributes presumptively lost during angiosperm evolution. These findings may account for the unique egg cell specification characteristic of angiosperms and the formation of seeds with single diploid embryos while containing endosperm that can have variable numbers of parental haploid genomes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pagnussat, Gabriela C -- Alandete-Saez, Monica -- Bowman, John L -- Sundaresan, Venkatesan -- New York, N.Y. -- Science. 2009 Jun 26;324(5935):1684-9. doi: 10.1126/science.1167324. Epub 2009 Jun 4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Plant Biology, University of California, Davis, CA 95616, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19498110" target="_blank"〉PubMed〈/a〉
    Keywords: Arabidopsis/*cytology/genetics/growth & development/*metabolism ; Arabidopsis Proteins/genetics/metabolism ; Biological Evolution ; Down-Regulation ; Flowers/*cytology/growth & development/metabolism ; Gene Expression Regulation, Plant ; Genes, Plant ; Germ Cells/*cytology/growth & development/metabolism ; Indoleacetic Acids/*metabolism ; Membrane Transport Proteins/genetics/metabolism ; MicroRNAs ; Mitosis ; Models, Biological ; Oxygenases/genetics/metabolism ; Recombinant Fusion Proteins/metabolism ; Seeds/cytology ; Signal Transduction
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  • 87
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    Nature Publishing Group (NPG)
    Publication Date: 2008-11-21
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉England -- Nature. 2008 Nov 20;456(7220):317-8. doi: 10.1038/456317a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19020598" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Anniversaries and Special Events ; Biodiversity ; *Biological Evolution ; Epidemiology/trends ; Humans ; Models, Biological ; Mutagenesis ; Religion and Science ; Science/*trends ; Selection, Genetic
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
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  • 88
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    Nature Publishing Group (NPG)
    Publication Date: 2008-06-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Luo, Ji -- Elledge, Stephen J -- England -- Nature. 2008 Jun 19;453(7198):995-6. doi: 10.1038/453995a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18563141" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Transformation, Neoplastic/*genetics ; Colonic Neoplasms/genetics/pathology ; Gene Expression Regulation, Neoplastic ; Genes, p53/genetics ; Genes, ras/genetics ; Humans ; Models, Biological ; Oncogenes/*genetics
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  • 89
    Publication Date: 2008-08-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ingolia, Nicholas T -- Weissman, Jonathan S -- England -- Nature. 2008 Aug 28;454(7208):1059-62. doi: 10.1038/4541059a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18756243" target="_blank"〉PubMed〈/a〉
    Keywords: *Environment ; Galactose/metabolism ; *Gene Expression Regulation, Fungal/drug effects ; Glucose/metabolism/pharmacology ; Metabolic Networks and Pathways/drug effects/*genetics ; Microfluidics ; Models, Biological ; Osmotic Pressure ; RNA Stability/drug effects ; Saccharomyces cerevisiae/classification/drug effects/*genetics/*metabolism ; Systems Biology
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  • 90
    Publication Date: 2008-02-26
    Description: Maintaining cell shape and tone is crucial for the function and survival of cells and tissues. Mechanotransduction relies on the transformation of minuscule mechanical forces into high-fidelity electrical responses. When mechanoreceptors are stimulated, mechanically sensitive cation channels open and produce an inward transduction current that depolarizes the cell. For this process to operate effectively, the transduction machinery has to retain integrity and remain unfailingly independent of environmental changes. This is particularly challenging for poikilothermic organisms, where changes in temperature in the environment may impact the function of mechanoreceptor neurons. Thus, we wondered how insects whose habitat might quickly vary over several tens of degrees of temperature manage to maintain highly effective mechanical senses. We screened for Drosophila mutants with defective mechanical responses at elevated ambient temperatures, and identified a gene, spam, whose role is to protect the mechanosensory organ from massive cellular deformation caused by heat-induced osmotic imbalance. Here we show that Spam protein forms an extracellular shield that guards mechanosensory neurons from environmental insult. Remarkably, heterologously expressed Spam protein also endowed other cells with superb defence against physically and chemically induced deformation. We studied the mechanical impact of Spam coating and show that spam-coated cells are up to ten times stiffer than uncoated controls. Together, these results help explain how poikilothermic organisms preserve the architecture of critical cells during environmental stress, and illustrate an elegant and simple solution to such challenge.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2387185/" 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/PMC2387185/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cook, Boaz -- Hardy, Robert W -- McConnaughey, William B -- Zuker, Charles S -- R01 EY006979/EY/NEI NIH HHS/ -- R01 EY006979-18/EY/NEI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2008 Mar 20;452(7185):361-4. doi: 10.1038/nature06603. Epub 2008 Feb 24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute and Departments of Neurobiology and Neurosciences, University of California at San Diego, La Jolla, California 92093-0649, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18297055" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Cell Shape/*drug effects/*physiology ; Drosophila Proteins/genetics/metabolism ; Drosophila melanogaster/*cytology/drug effects/genetics/physiology ; Electrophysiology ; *Environment ; Eye Proteins/genetics/metabolism ; Hot Temperature ; Humidity ; Mechanoreceptors/cytology/physiology ; Mechanotransduction, Cellular/*drug effects/*physiology ; Models, Biological ; Osmotic Pressure ; Stimulation, Chemical ; Stress, Mechanical
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  • 91
    Publication Date: 2008-03-07
    Description: Complex dynamics are often shown by simple ecological models and have been clearly demonstrated in laboratory and natural systems. Yet many classes of theoretically possible dynamics are still poorly documented in nature. Here we study long-term time-series data of a midge, Tanytarsus gracilentus (Diptera: Chironomidae), in Lake Myvatn, Iceland. The midge undergoes density fluctuations of almost six orders of magnitude. Rather than regular cycles, however, these fluctuations have irregular periods of 4-7 years, indicating complex dynamics. We fit three consumer-resource models capable of qualitatively distinct dynamics to the data. Of these, the best-fitting model shows alternative dynamical states in the absence of environmental variability; depending on the initial midge densities, the model shows either fluctuations around a fixed point or high-amplitude cycles. This explains the observed complex population dynamics: high-amplitude but irregular fluctuations occur because stochastic variability causes the dynamics to switch between domains of attraction to the alternative states. In the model, the amplitude of fluctuations depends strongly on minute resource subsidies into the midge habitat. These resource subsidies may be sensitive to human-caused changes in the hydrology of the lake, with human impacts such as dredging leading to higher-amplitude fluctuations. Tanytarsus gracilentus is a key component of the Myvatn ecosystem, representing two-thirds of the secondary productivity of the lake and providing vital food resources to fish and to breeding bird populations. Therefore the high-amplitude, irregular fluctuations in midge densities generated by alternative dynamical states dominate much of the ecology of the lake.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ives, Anthony R -- Einarsson, Arni -- Jansen, Vincent A A -- Gardarsson, Arnthor -- England -- Nature. 2008 Mar 6;452(7183):84-7. doi: 10.1038/nature06610.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA. arives@wisc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18322533" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Chironomidae/*physiology ; Computer Simulation ; *Ecosystem ; Eukaryota/physiology ; Food ; *Fresh Water ; Iceland ; Models, Biological ; Population Density ; Stochastic Processes
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  • 92
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    Nature Publishing Group (NPG)
    Publication Date: 2008-06-06
    Description: 〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2865228/" 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/PMC2865228/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Warburton, David -- P01 HL060231/HL/NHLBI NIH HHS/ -- P01 HL060231-09/HL/NHLBI NIH HHS/ -- R01 HL044060/HL/NHLBI NIH HHS/ -- R01 HL044977/HL/NHLBI NIH HHS/ -- R01 HL044977-16/HL/NHLBI NIH HHS/ -- England -- Nature. 2008 Jun 5;453(7196):733-5. doi: 10.1038/453733a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18528385" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptor Proteins, Signal Transducing ; Animals ; Body Patterning/genetics/*physiology ; Fibroblast Growth Factor 10/metabolism ; Intracellular Signaling Peptides and Proteins ; Lung/*anatomy & histology/*embryology/metabolism ; Membrane Proteins/metabolism ; Mice ; Models, Biological ; Organogenesis/genetics/*physiology ; Receptor, Fibroblast Growth Factor, Type 2/genetics/metabolism
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  • 93
    Publication Date: 2008-04-11
    Description: There exists controversy over the nature of haematopoietic progenitors of T cells. Most T cells develop in the thymus, but the lineage potential of thymus-colonizing progenitors is unknown. One approach to resolving this question is to determine the lineage potentials of the earliest thymic progenitors (ETPs). Previous work has shown that ETPs possess T and natural killer lymphoid potentials, and rare subsets of ETPs also possess B lymphoid potential, suggesting an origin from lymphoid-restricted progenitor cells. However, whether ETPs also possess myeloid potential is unknown. Here we show that nearly all ETPs in adult mice possess both T and myeloid potential in clonal assays. The existence of progenitors possessing T and myeloid potential within the thymus is incompatible with the current dominant model of haematopoiesis, in which T cells are proposed to arise from lymphoid-. Our results indicate that alternative models for lineage commitment during haematopoiesis must be considered.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bell, J Jeremiah -- Bhandoola, Avinash -- England -- Nature. 2008 Apr 10;452(7188):764-7. doi: 10.1038/nature06840.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18401411" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Cell Lineage ; Cells, Cultured ; Coculture Techniques ; Dendritic Cells/cytology ; Female ; Granulocytes/cytology ; *Hematopoiesis ; Hematopoietic Stem Cells/*cytology/metabolism ; Macrophages/cytology ; Mice ; Models, Biological ; Myeloid Cells/*cytology/metabolism ; Stromal Cells/cytology ; T-Lymphocytes/*cytology/metabolism ; Thymus Gland/*cytology
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  • 94
    Publication Date: 2008-10-03
    Description: The integrity of the cornea, the most anterior part of the eye, is indispensable for vision. Forty-five million individuals worldwide are bilaterally blind and another 135 million have severely impaired vision in both eyes because of loss of corneal transparency; treatments range from local medications to corneal transplants, and more recently to stem cell therapy. The corneal epithelium is a squamous epithelium that is constantly renewing, with a vertical turnover of 7 to 14 days in many mammals. Identification of slow cycling cells (label-retaining cells) in the limbus of the mouse has led to the notion that the limbus is the niche for the stem cells responsible for the long-term renewal of the cornea; hence, the corneal epithelium is supposedly renewed by cells generated at and migrating from the limbus, in marked opposition to other squamous epithelia in which each resident stem cell has in charge a limited area of epithelium. Here we show that the corneal epithelium of the mouse can be serially transplanted, is self-maintained and contains oligopotent stem cells with the capacity to generate goblet cells if provided with a conjunctival environment. Furthermore, the entire ocular surface of the pig, including the cornea, contains oligopotent stem cells (holoclones) with the capacity to generate individual colonies of corneal and conjunctival cells. Therefore, the limbus is not the only niche for corneal stem cells and corneal renewal is not different from other squamous epithelia. We propose a model that unifies our observations with the literature and explains why the limbal region is enriched in stem cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Majo, Francois -- Rochat, Ariane -- Nicolas, Michael -- Jaoude, Georges Abou -- Barrandon, Yann -- England -- Nature. 2008 Nov 13;456(7219):250-4. doi: 10.1038/nature07406. Epub 2008 Oct 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Stem Cell Dynamics, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne CH, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18830243" target="_blank"〉PubMed〈/a〉
    Keywords: Adult Stem Cells/*cytology ; Animals ; Cattle ; Cells, Cultured ; Child, Preschool ; Clone Cells ; Corneal Transplantation ; Epithelium, Corneal/*cytology/metabolism ; Female ; Gene Expression Regulation ; Humans ; Infant ; Keratinocytes/cytology/metabolism ; Male ; Mice ; Mice, SCID ; Models, Biological ; Multipotent Stem Cells/*cytology ; Proteins/metabolism ; Rats ; Swine
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  • 95
    Publication Date: 2008-01-22
    Description: Understanding the mechanisms that determine an individual's sex remains a primary challenge for evolutionary biology. Chromosome-based systems (genotypic sex determination) that generate roughly equal numbers of sons and daughters accord with theory, but the adaptive significance of environmental sex determination (that is, when embryonic environmental conditions determine offspring sex, ESD) is a major unsolved problem. Theoretical models predict that selection should favour ESD over genotypic sex determination when the developmental environment differentially influences male versus female fitness (that is, the Charnov-Bull model), but empirical evidence for this hypothesis remains elusive in amniote vertebrates--the clade in which ESD is most prevalent. Here we provide the first substantial empirical support for this model by showing that incubation temperatures influence reproductive success of males differently than that of females in a short-lived lizard (Amphibolurus muricatus, Agamidae) with temperature-dependent sex determination. We incubated eggs at a variety of temperatures, and de-confounded sex and incubation temperature by using hormonal manipulations to embryos. We then raised lizards in field enclosures and quantified their lifetime reproductive success. Incubation temperature affected reproductive success differently in males versus females in exactly the way predicted by theory: the fitness of each sex was maximized by the incubation temperature that produces that sex. Our results provide unequivocal empirical support for the Charnov-Bull model for the adaptive significance of temperature-dependent sex determination in amniote vertebrates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Warner, D A -- Shine, R -- England -- Nature. 2008 Jan 31;451(7178):566-8. doi: 10.1038/nature06519. Epub 2008 Jan 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia. dwarner@iastate.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18204437" target="_blank"〉PubMed〈/a〉
    Keywords: Acclimatization/physiology ; Adaptation, Physiological/*physiology ; Animals ; Body Size ; Fadrozole/pharmacology ; Female ; Lizards/*embryology/*physiology ; Male ; Models, Biological ; Ovum/drug effects/growth & development ; Reproduction/physiology ; Sex Characteristics ; Sex Differentiation/*physiology ; *Temperature
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  • 96
    Publication Date: 2008-02-15
    Description: Mathematical models predict that species interactions such as competition and predation can generate chaos. However, experimental demonstrations of chaos in ecology are scarce, and have been limited to simple laboratory systems with a short duration and artificial species combinations. Here, we present the first experimental demonstration of chaos in a long-term experiment with a complex food web. Our food web was isolated from the Baltic Sea, and consisted of bacteria, several phytoplankton species, herbivorous and predatory zooplankton species, and detritivores. The food web was cultured in a laboratory mesocosm, and sampled twice a week for more than 2,300 days. Despite constant external conditions, the species abundances showed striking fluctuations over several orders of magnitude. These fluctuations displayed a variety of different periodicities, which could be attributed to different species interactions in the food web. The population dynamics were characterized by positive Lyapunov exponents of similar magnitude for each species. Predictability was limited to a time horizon of 15-30 days, only slightly longer than the local weather forecast. Hence, our results demonstrate that species interactions in food webs can generate chaos. This implies that stability is not required for the persistence of complex food webs, and that the long-term prediction of species abundances can be fundamentally impossible.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beninca, Elisa -- Huisman, Jef -- Heerkloss, Reinhard -- Johnk, Klaus D -- Branco, Pedro -- Van Nes, Egbert H -- Scheffer, Marten -- Ellner, Stephen P -- England -- Nature. 2008 Feb 14;451(7180):822-5. doi: 10.1038/nature06512.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Nieuwe Achtergracht 127, 1018 WS Amsterdam, The Netherlands.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18273017" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bacteria/metabolism ; *Food Chain ; Models, Biological ; *Nonlinear Dynamics ; Oceans and Seas ; Plankton/*metabolism ; Population Dynamics ; Species Specificity ; Time Factors
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  • 97
    Publication Date: 2008-06-27
    Description: In groundbreaking experiments, Hans Spemann demonstrated that the dorsal part of the amphibian embryo can generate a well-proportioned tadpole, and that a small group of dorsal cells, the 'organizer', can induce a complete and well-proportioned twinned axis when transplanted into a host embryo. Key to organizer function is the localized secretion of inhibitors of bone morphogenetic protein (BMP), which defines a graded BMP activation profile. Although the central proteins involved in shaping this gradient are well characterized, their integrated function, and in particular how pattern scales with size, is not understood. Here we present evidence that in Xenopus, the BMP activity gradient is defined by a 'shuttling-based' mechanism, whereby the BMP ligands are translocated ventrally through their association with the BMP inhibitor Chordin. This shuttling, with feedback repression of the BMP ligand Admp, offers a quantitative explanation to Spemann's observations, and accounts naturally for the scaling of embryo pattern with its size.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ben-Zvi, Danny -- Shilo, Ben-Zion -- Fainsod, Abraham -- Barkai, Naama -- England -- Nature. 2008 Jun 26;453(7199):1205-11. doi: 10.1038/nature07059.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18580943" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Body Patterning ; Body Size ; Bone Morphogenetic Protein 4 ; Bone Morphogenetic Proteins/antagonists & inhibitors/*metabolism ; Embryo, Nonmammalian/embryology/*metabolism ; Glycoproteins/metabolism ; Intercellular Signaling Peptides and Proteins/metabolism ; Ligands ; Models, Biological ; Protein Transport ; Xenopus/*embryology/genetics/metabolism ; Xenopus Proteins/metabolism
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  • 98
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    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2008-05-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mandavilli, Apoorva -- England -- Nature. 2008 May 29;453(7195):581-2. doi: 10.1038/453581a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18509413" target="_blank"〉PubMed〈/a〉
    Keywords: Adult ; Defensins/metabolism ; *Ecosystem ; Feces/*microbiology ; Female ; Humans ; Infant, Newborn ; Intestines/*microbiology/*transplantation ; Models, Biological ; Nod2 Signaling Adaptor Protein/genetics/metabolism
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  • 99
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    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2008-02-14
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Speakman, John -- England -- Nature. 2008 Feb 14;451(7180):774-5. doi: 10.1038/451774a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18270540" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Chiroptera/anatomy & histology/*physiology ; Cochlea/anatomy & histology/physiology ; Darkness ; Echolocation/*physiology ; Extremities/anatomy & histology/physiology ; Flight, Animal/*physiology ; Fossils ; Models, Biological ; Time Factors ; Wyoming
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  • 100
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    Unknown
    Nature Publishing Group (NPG)
    Publication Date: 2008-02-01
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jones, Dan -- England -- Nature. 2008 Jan 31;451(7178):512-5. doi: 10.1038/451512a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18235473" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Physiological ; Aggression/*physiology/psychology ; Altruism ; Anger/physiology ; Animals ; Antisocial Personality Disorder/physiopathology ; *Biological Evolution ; Conflict (Psychology) ; Female ; History, 15th Century ; History, 16th Century ; History, 17th Century ; History, 18th Century ; History, 19th Century ; History, 20th Century ; History, 21st Century ; History, Medieval ; *Homicide/history/psychology ; Humans ; Male ; Models, Biological ; Morals ; Pan troglodytes/physiology ; Prefrontal Cortex/anatomy & histology/physiology ; Sex Characteristics ; United Nations ; Violence/psychology ; Warfare
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