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Plos Biology : Systematic in Vivo Analysis of the Intrinsic Determ...

By: Jonathan S. Weissman

Description : Protein aggregation into amyloid fibrils and protofibrillar aggregates is associated with a number of the most common neurodegenerative diseases. We have established, using a computational approach, that knowledge of the primary sequences of proteins is sufficient to predict their in vitro aggregation propensities. Here we demonstrate, using rational mutagenesis of the Ab42 peptide based on such computational predictions of aggregation propensity, the exist...

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Plos Biology : Invertebrate Post-segregation Distorters ; a New Em...

By: Public Library of Science (Plos)

Description : Cytoplasmic incompatibility induced by inherited intracellular bacteria of arthropods, and Medea elements found in flour beetles, are both forms of postsegregation distortion involving the killing of embryos in order to increase the ratio of progeny that inherit them. The recently described peel-zeel element of Caenorhabditis elegans also uses this mechanism: like Medea the genes responsible are in the nuclear genome but it shares a paternal mode of action ...

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Plos Biology : Dual Host-virus Arms Races Shape an Essential House...

By: Bill Sugden

Description : Transferrin Receptor (TfR1) is the cell-surface receptor that regulates iron uptake into cells, a process that is fundamental to life. However, TfR1 also facilitates the cellular entry of multiple mammalian viruses. We use evolutionary and functional analyses of TfR1 in the rodent clade, where two families of viruses bind this receptor, to mechanistically dissect how essential housekeeping genes like TFR1 successfully balance the opposing selective pressure...

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Plos Biology : Using Grizzly Bears to Assess Harvest-ecosystem Tra...

By: Stephen P. Ellner

Description : Implementation of ecosystem-based fisheries management (EBFM) requires a clear conceptual and quantitative framework for assessing how different harvest options can modify benefits to ecosystem and human beneficiaries. We address this social-ecological need for Pacific salmon fisheries, which are economically valuable but intercept much of the annual pulse of nutrient subsidies that salmon provide to terrestrial and aquatic food webs. We used grizzly bears,...

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Plos Biology : Divergent Selection and the Evolution of Signal Tra...

By: Joel Kingsolver

Description : Mating preferences are common in natural populations, and their divergence among populations is considered an important source of reproductive isolation during speciation. Although mechanisms for the divergence of mating preferences have received substantial theoretical treatment, complementary experimental tests are lacking. We conducted a laboratory evolution experiment, using the fruit fly Drosophila serrata, to explore the role of divergent selection be...

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Plos Biology : Independently Evolving Species in Asexual Bdelloid ...

By: Mohamed A. F. Noor

Description : Asexuals are an important test case for theories of why species exist. If asexual clades displayed the same pattern of discrete variation as sexual clades, this would challenge the traditional view that sex is necessary for diversification into species. However, critical evidence has been lacking : all putative examples have involved organisms with recent or ongoing histories of recombination and have relied on visual interpretation of patterns of genetic a...

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Plos Biology : Nuclear Receptor Dhr4 Controls the Timing of Steroi...

By: David S. Schneider

Description : In insects, precisely timed periodic pulses of the molting hormone ecdysone control major developmental transitions such as molts and metamorphosis. The synthesis and release of ecdysone, a steroid hormone, is itself controlled by PTTH (prothoracicotopic hormone). PTTH transcript levels oscillate with an 8 h rhythm, but its significance regarding the timing of ecdysone pulses is unclear. PTTH acts on its target tissue, the prothoracic gland (PG), by activat...

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Plos Biology : Perception Space—the Final Frontier, Volume 3

By: Lars Chittka

Description : Philosophers have correctly pointed out that we cannot actually imagine what it is like to perceive the world through other animals’ sense organs [38]. But studies such as those by Guerrieri et al. [8] show elegantly how to attach scales and numbers to the inner worlds proposed by von Uexküll a century ago. Mapping these worlds quantitatively will allow us to compare them between related species operating in different environments, to see how the architectu...

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Plos Biology : the Period Length of Fibroblast Circadian Gene Expr...

By: Emmanuel Mignot

Description : Mammalian circadian behavior is governed by a central clock in the suprachiasmatic nucleus of the brain hypothalamus, and its intrinsic period length is believed to affect the phase of daily activities. Measurement of this period length, normally accomplished by prolonged subject observation, is difficult and costly in humans. Because a circadian clock similar to that of the suprachiasmatic nucleus is present in most cell types, we were able to engineer a l...

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Plos Biology : Large-scale Mapping and Validation of Escherichia C...

By: Andre Levchenko

Description : Machine learning approaches offer the potential to systematically identify transcriptional regulatory interactions from a compendium of microarray expression profiles. However, experimental validation of the performance of these methods at the genome scale has remained elusive. Here we assess the global performance of four existing classes of inference algorithms using 445 Escherichia coli Affymetrix arrays and 3,216 known E. coli regulatory interactions fr...

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Plos Biology : the Ndr, Volume 6

By: Emily Mazanka

Description : Cell fate can be determined by asymmetric segregation of gene expression regulators. In the budding yeast Saccharomyces cerevisiae, the transcription factor Ace2 accumulates specifically in the daughter cell nucleus, where it drives transcription of genes that are not expressed in the mother cell. The NDR/LATS family protein kinase Cbk1 is required for Ace2 segregation and function. Using peptide scanning arrays, we determined Cbk19s phosphorylation consens...

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Plos Biology : Phase Coupling of a Circadian Neuropeptide with Res...

By: Ying Wu

Description : Drosophila clock neurons are self-sustaining cellular oscillators that rely on negative transcriptional feedback to keep circadian time. Proper regulation of organismal rhythms of physiology and behavior requires coordination of the oscillations of individual clock neurons within the circadian control network. Over the last decade, it has become clear that a key mechanism for intercellular communication in the circadian network is signaling between a subset...

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Plos Biology : Beyond Competition ; Incorporating Positive Interac...

By: Fabio Bulleri
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Plos Biology : as the Antarctic Ice Pack Recedes, a Fragile Ecosys...

By: Liza Gross
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Plos Biology : Fifty Thousand Years of Extinction, Volume 9

By: Public Library of Science (Plos)
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Plos Biology : Activation of Nk Cells by an Endocytosed Receptor f...

By: Hidde Ploegh

Description : Signaling from endosomes is emerging as a mechanism by which selected receptors provide sustained signals distinct from those generated at the plasma membrane. The activity of natural killer (NK) cells, which are important effectors of innate immunity and regulators of adaptive immunity, is controlled primarily by receptors that are at the cell surface. Here we show that cytokine secretion by resting human NK cells is induced by soluble, but not solid-phase...

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Plos Biology : Precise Temperature Compensation of Phase in a Rhyt...

By: William A. Harris

Description : Most animal species are cold-blooded, and their neuronal circuits must maintain function despite environmental temperature fluctuations. The central pattern generating circuits that produce rhythmic motor patterns depend on the orderly activation of circuit neurons. We describe the effects of temperature on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. The pyloric rhythm is a triphasic motor pattern in which the Pyloric Dil...

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Plos Biology : T Cell Receptor-independent Basal Signaling Via Erk...

By: Philippa Marrack

Description : Signal transduction pathways guided by cellular receptors commonly exhibit low-level constitutive signaling in a continuous, ligand-independent manner. The dynamic equilibrium of positive and negative regulators establishes such a tonic signal. Ligand-independent signaling by the precursors of mature antigen receptors regulates development of B and T lymphocytes. Here we describe a basal signal that controls gene expression profiles in the Jurkat T cell lin...

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Plos Biology : Bmal1 and Clock, Two Essential Components of the Ci...

By: Steve O’rahilly

Description : Circadian timing is generated through a unique series of autoregulatory interactions termed the molecular clock. Behavioral rhythms subject to the molecular clock are well characterized. We demonstrate a role for Bmal1 and Clock in the regulation of glucose homeostasis. Inactivation of the known clock components Bmal1 (Mop3) and Clock suppress the diurnal variation in glucose and triglycerides. Gluconeogenesis is abolished by deletion of Bmal1 and is depres...

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Plos Biology : the Chromosomal Passenger Complex Activates Polo Ki...

By: R. Scott Hawley

Description : The coordinated activities at centromeres of two key cell cycle kinases, Polo and Aurora B, are critical for ensuring that the two sister kinetochores of each chromosome are attached to microtubules from opposite spindle poles prior to chromosome segregation at anaphase. Initial attachments of chromosomes to the spindle involve random interactions between kinetochores and dynamic microtubules, and errors occur frequently during early stages of the process. ...

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