Proceedings of the Natural Academy of Sciences

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Bcl6 middle domain function in Tfh cells [Immunology and Inflammation]

Tue, 10/27/2015 - 12:31
T follicular helper (Tfh) cells are essential providers of help to B cells. The transcription factor B-cell CLL/lymphoma 6 (Bcl6) is a lineage-defining regulator of Tfh cells and germinal center B cells. In B cells, Bcl6 has the potential to recruit distinct transcriptional corepressors through its BTB domain or its...
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IL-7R controls Treg function [Immunology and Inflammation]

Tue, 10/27/2015 - 12:31
Foxp3+CD4+ regulatory T cells (Treg) have a crucial role in controlling CD4+ T-cell activation, proliferation, and effector function. However, the molecular mechanisms regulating Treg function remain poorly understood. Here we assessed the role of IL-7, a key cytokine regulating T-cell homeostasis, in suppressor capacity of Treg. Using a skin allograft...
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Noninvasive monitoring after lung transplantation [Medical Sciences]

Tue, 10/27/2015 - 12:31
The survival rate following lung transplantation is among the lowest of all solid-organ transplants, and current diagnostic tests often fail to distinguish between infection and rejection, the two primary posttransplant clinical complications. We describe a diagnostic assay that simultaneously monitors for rejection and infection in lung transplant recipients by sequencing...
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Multifaceted roles of Shp2 and Pten in blood [Medical Sciences]

Tue, 10/27/2015 - 12:31
Previous data suggested a negative role of phosphatase and tensin homolog (Pten) and a positive function of SH2-containing tyrosine phosphatase (Shp2)/Ptpn11 in myelopoiesis and leukemogenesis. Herein we demonstrate that ablating Shp2 indeed suppressed the myeloproliferative effect of Pten loss, indicating directly opposing functions between pathways regulated by these two enzymes....
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Similar molecules from different genetic contexts [Microbiology]

Tue, 10/27/2015 - 12:31
Small molecules produced by Actinobacteria have played a prominent role in both drug discovery and organic chemistry. As part of a larger study of the actinobacterial symbionts of fungus-growing ants, we discovered a small family of three previously unreported piperazic acid-containing cyclic depsipeptides, gerumycins A–C. The gerumycins are slightly smaller...
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Mechanism and allosteric regulation of SAS1 [Microbiology]

Tue, 10/27/2015 - 12:31
Nucleotide-based second messengers serve in the response of living organisms to environmental changes. In bacteria and plant chloroplasts, guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) [collectively named “(p)ppGpp”] act as alarmones that globally reprogram cellular physiology during various stress conditions. Enzymes of the RelA/SpoT homology (RSH) family synthesize (p)ppGpp by...
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Endogenous neurogenesis after SCI [Neuroscience]

Tue, 10/27/2015 - 12:31
Neural stem cells (NSCs) in the adult mammalian central nervous system (CNS) hold the key to neural regeneration through proper activation, differentiation, and maturation, to establish nascent neural networks, which can be integrated into damaged neural circuits to repair function. However, the CNS injury microenvironment is often inhibitory and inflammatory,...
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Transciptome analyses reveal pathology after SCI [Neuroscience]

Tue, 10/27/2015 - 12:31
Spinal cord injury (SCI) is considered incurable because axonal regeneration in the central nervous system (CNS) is extremely challenging, due to harsh CNS injury environment and weak intrinsic regeneration capability of CNS neurons. We discovered that neurotrophin-3 (NT3)-loaded chitosan provided an excellent microenvironment to facilitate nerve growth, new neurogenesis, and...
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SPARC triggers a program of synapse elimination [Neuroscience]

Tue, 10/27/2015 - 12:31
Elimination of the excess synaptic contacts established in the early stages of neuronal development is required to refine the function of neuronal circuits. Here we investigate whether secreted protein acidic and rich in cysteine (SPARC), a molecule produced by glial cells, is involved in synapse removal. SPARC production peaks when...
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Lateral chirality-sorting optical forces [Physics]

Tue, 10/27/2015 - 12:31
The transverse component of the spin angular momentum of evanescent waves gives rise to lateral optical forces on chiral particles, which have the unusual property of acting in a direction in which there is neither a field gradient nor wave propagation. Because their direction and strength depends on the chiral...
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Blue-phase liquid crystal droplets [Physics]

Tue, 10/27/2015 - 12:31
Blue phases of liquid crystals represent unique ordered states of matter in which arrays of defects are organized into striking patterns. Most studies of blue phases to date have focused on bulk properties. In this work, we present a systematic study of blue phases confined into spherical droplets. It is...
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Auxin signaling in maize inflorescences [Plant Biology]

Tue, 10/27/2015 - 12:31
In plants, small groups of pluripotent stem cells called axillary meristems are required for the formation of the branches and flowers that eventually establish shoot architecture and drive reproductive success. To ensure the proper formation of new axillary meristems, the specification of boundary regions is required for coordinating their development....
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Transcripts move from the vegetative cell to sperm [Plant Biology]

Tue, 10/27/2015 - 12:31
An Arabidopsis pollen grain (male gametophyte) consists of three cells: the vegetative cell, which forms the pollen tube, and two sperm cells enclosed within the vegetative cell. It is still unclear if there is intercellular communication between the vegetative cell and the sperm cells. Here we show that ABA-hypersensitive germination3...
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Passive-dynamic pitcher plant trap [Plant Biology]

Tue, 10/27/2015 - 12:31
Plants use rapid movements to disperse seed, spores, or pollen and catch animal prey. Most rapid-release mechanisms only work once and, if repeatable, regaining the prerelease state is a slow and costly process. We present an encompassing mechanism for a rapid, repeatable, passive-dynamic motion used by a carnivorous pitcher plant...
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Origin of plant symbiotic genes [Plant Biology]

Tue, 10/27/2015 - 12:31
Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these...
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Cross-immunity between strains of paramyxoviruses [Population Biology]

Tue, 10/27/2015 - 12:31
Viral respiratory tract diseases pose serious public health problems. Our ability to predict and thus, be able to prepare for outbreaks is strained by the complex factors driving the prevalence and severity of these diseases. The abundance of diseases and transmission dynamics of strains are not only affected by external...
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Perception and prior knowledge in psychosis [Psychological and Cognitive Sciences]

Tue, 10/27/2015 - 12:31
Many neuropsychiatric illnesses are associated with psychosis, i.e., hallucinations (perceptions in the absence of causative stimuli) and delusions (irrational, often bizarre beliefs). Current models of brain function view perception as a combination of two distinct sources of information: bottom-up sensory input and top-down influences from prior knowledge. This framework may...
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Effects of reward on estimated effort [Psychological and Cognitive Sciences]

Tue, 10/27/2015 - 12:31
Effort and reward jointly shape many human decisions. Errors in predicting the required effort needed for a task can lead to suboptimal behavior. Here, we show that effort estimations can be biased when retrospectively reestimated following receipt of a rewarding outcome. These biases depend on the contingency between reward and...
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Gender-biased evaluations of gender-bias evidence [Psychological and Cognitive Sciences]

Tue, 10/27/2015 - 12:31
Scientists are trained to evaluate and interpret evidence without bias or subjectivity. Thus, growing evidence revealing a gender bias against women—or favoring men—within science, technology, engineering, and mathematics (STEM) settings is provocative and raises questions about the extent to which gender bias may contribute to women’s underrepresentation within STEM fields....
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Spatio-temporal dynamics of ecosystem services [Sustainability Science]

Tue, 10/27/2015 - 12:31
Managing multiple ecosystem services (ES), including addressing trade-offs between services and preventing ecological surprises, is among the most pressing areas for sustainability research. These challenges require ES research to go beyond the currently common approach of snapshot studies limited to one or two services at a single point in time....
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