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Plos Biology : a Sex-ratio Meiotic Drive System in Drosophila Simu...

By: Daniel Barbash

Description : Sex ratio distortion (sex-ratio for short) has been reported in numerous species such as Drosophila, where distortion can readily be detected in experimental crosses, but the molecular mechanisms remain elusive. Here we characterize an autosomal sex-ratio suppressor from D. simulans that we designate as not much yang (nmy, polytene chromosome position 87F3). Nmy suppresses an X-linked sex-ratio distorter, contains a pair of near-perfect inverted repeats of ...

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Plos Biology : Conflict Over Male Parentage in Social Insects, Vol...

By: Ross Crozier

Description : Mutual policing is an important mechanism that maintains social harmony in group-living organisms by suppressing the selfish behavior of individuals. In social insects, workers police one another (worker-policing) by preventing individual workers from laying eggs that would otherwise develop into males. Within the framework of Hamilton’s rule there are two explanations for worker-policing behavior. First, if worker reproduction is cost-free, worker-policing...

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Plos Biology : Organized Unidirectional Waves of Atp Hydrolysis Wi...

By: James E. Haber

Description : The RecA protein forms nucleoprotein filaments on DNA, and individual monomers within the filaments hydrolyze ATP. Assembly and disassembly of filaments are both unidirectional, occurring on opposite filament ends, with disassembly requiring ATP hydrolysis. When filaments form on duplex DNA, RecA protein exhibits a functional state comparable to the state observed during active DNA strand exchange. RecA filament state was monitored with a coupled spectropho...

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Plos Biology : Alternative Mating Type Configurations A, Volume 9

By: Joseph Heitman

Description : Similar multicellular structures can evolve within the same organism that may have different evolutionary histories, be controlled by different regulatory pathways, and play similar but nonidentical roles. In the human fungal pathogen Candida albicans, a quite extraordinary example of this has occurred. Depending upon the configuration of the mating type locus (a/ a versus a/a or a/a), C. albicans forms alternative biofilms that appear similar morphological...

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Plos Biology : Modern Humans Did Not Admix with Neanderthals Durin...

By: David Penny

Description : The process by which the Neanderthals were replaced by modern humans between 42,000 and 30,000 before present is still intriguing. Although no Neanderthal mitochondrial DNA (mtDNA) lineage is found to date among several thousands of Europeans and in seven early modern Europeans, interbreeding rates as high as 25% could not be excluded between the two subspecies. In this study, we introduce a realistic model of the range expansion of early modern humans into...

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Plos Biology : Light-dependent Development of Circadian Gene Expre...

By: Ueli Schibler

Description : The roles of environmental stimuli in initiation and synchronization of circadian oscillation during development appear to vary among different rhythmic processes. In zebrafish, a variety of rhythms emerge in larvae only after exposure to light-dark (LD) cycles, whereas zebrafish period3 (per3) mRNA has been reported to be rhythmic from day 1 of development in constant conditions. We generated transgenic zebrafish in which expression of the firefly lucifera...

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Plos Biology : Selective Remodeling ; Refining Neural Connectivity...

By: Won-suk Chung
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Plos Biology : a Toxoplasma Gondii Pseudokinase Inhibits Host Irg ...

By: Erik Sahai

Description : The ability of mice to resist infection with the protozoan parasite, Toxoplasma gondii, depends in large part on the function of members of a complex family of atypical large GTPases, the interferon-gamma-inducible immunity-related GTPases (IRG proteins). Nevertheless, some strains of T. gondii are highly virulent for mice because, as recently shown, they secrete a polymorphic protein kinase, ROP18, from the rhoptries into the host cell cytosol at the momen...

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Plos Biology : Modeling T Cell Antigen Discrimination Based on Fee...

By: Philippa Marrack

Description : T-lymphocyte activation displays a remarkable combination of speed, sensitivity, and discrimination in response to peptide–major histocompatibility complex (pMHC) ligand engagement of clonally distributed antigen receptors (T cell receptors or TCRs). Even a few foreign pMHCs on the surface of an antigen-presenting cell trigger effective signaling within seconds, whereas 13105–13106 self-pMHC ligands that may differ from the foreign stimulus by only a single...

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Plos Biology : the Plos Community Journals, Volume 3

By: Mark Patterson
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Plos Biology : is Avoiding an Aversive Outcome Rewarding Neural Su...

By: Michela Gallagher

Description : Avoidance learning poses a challenge for reinforcement-based theories of instrumental conditioning, because once an aversive outcome is successfully avoided an individual may no longer experience extrinsic reinforcement for their behavior. One possible account for this is to propose that avoiding an aversive outcome is in itself a reward, and thus avoidance behavior is positively reinforced on each trial when the aversive outcome is successfully avoided. In...

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Plos Biology : a Post-burst Afterdepolarization is Mediated by Gro...

By: Alberto Bacci

Description : Activation of group I metabotropic glutamate receptors (subtypes mGluR1 and mGluR5) regulates neural activity in a variety of ways. In CA1 pyramidal neurons, activation of group I mGluRs eliminates the post-burst afterhyperpolarization (AHP) and produces an afterdepolarization (ADP) in its place. Here we show that upregulation of Cav2.3 R-type calcium channels is responsible for a component of the ADP lasting several hundred milliseconds. This medium-durati...

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Plos Biology : Stress-induced Out-of-context Activation of Memory,...

By: Matthew Shapiro

Description : Inappropriate recollections and responses in stressful conditions are hallmarks of post-traumatic stress disorder and other anxiety and mood disorders, but how stress contributes to the disorders is unclear. Here we show that stress itself reactivates memories even if the memory is unrelated to the stressful experience. Forced-swim stress one day after learning enhanced memory recall. One-day post-learning amnestic treatments were ineffective unless adminis...

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Plos Biology : What’s Killing American Honey Bees, Volume 5

By: Benjamin P. Oldroyd
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Plos Biology : N-terminal Phosphorylation of the Dopamine Transpor...

By: Eric Nestler

Description : Amphetamine (AMPH) elicits its behavioral effects by acting on the dopamine (DA) transporter (DAT) to induce DA efflux into the synaptic cleft. We previously demonstrated that a human DAT construct in which the first 22 amino acids were truncated was not phosphorylated by activation of protein kinase C, in contrast to wild-type (WT) DAT, which was phosphorylated. Nonetheless, in all functions tested to date, which include uptake, inhibitor binding, oligomer...

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Plos Biology : Bioassay-guided Evolution of Glycosylated MacRolide...

By: Adam P. Arkin

Description : Macrolide antibiotics such as erythromycin are clinically important polyketide natural products. We have engineered a recombinant strain of Escherichia coli that produces small but measurable quantities of the bioactive macrolide 6- deoxyerythromycin D. Bioassay-guided evolution of this strain led to the identification of an antibiotic-overproducing mutation in the mycarose biosynthesis and transfer pathway that was detectable via a colony-based screening a...

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Plos Biology : a Functional Analysis of the Spacer of Vdj Recombin...

By: Shizuo Akira

Description : During lymphocyte development, V(D)J recombination assembles antigen receptor genes from component V, D, and J gene segments. These gene segments are flanked by a recombination signal sequence (RSS), which serves as the binding site for the recombination machinery. The murine Jb2.6 gene segment is a recombinationally inactive pseudogene, but examination of its RSS reveals no obvious reason for its failure to recombine. Mutagenesis of the Jb2.6 RSS demonstra...

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Plos Biology : Specific Contributions of Ventromedial, Anterior Ci...

By: Tim Behrens

Description : Attentional control ensures that neuronal processes prioritize the most relevant stimulus in a given environment. Controlling which stimulus is attended thus originates from neurons encoding the relevance of stimuli, i.e. their expected value, in hand with neurons encoding contextual information about stimulus locations, features, and rules that guide the conditional allocation of attention. Here, we examined how these distinct processes are encoded and int...

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Plos Biology : Impaired Antibody Response Causes Persistence of Pr...

By: Sarah Rowland-jones

Description : CD8 T cells are recognized key players in control of persistent virus infections, but increasing evidence suggests that assistance from other immune mediators is also needed. Here, we investigated whether specific antibody responses contribute to control of lymphocytic choriomeningitis virus (LCMV), a prototypic mouse model of systemic persistent infection. Mice expressing transgenic B cell receptors of LCMV-unrelated specificity, and mice unable to produce...

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Plos Biology : Srp and Nac ; Guiding a Nascent Protein’s First Ste...

By: Public Library of Science (Plos)
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