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Preview: Proceedings of the National Academy of Sciences current issue

Proceedings of the National Academy of Sciences current issue



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In This Issue [This Week in PNAS]

2017-09-19T09:06:53-07:00

Human mobility in early Europe Burial of a nonlocal female in the Lech River valley area of southern Germany. Image courtesy of Stadtarchäologie Augsburg, Augsburg, Germany. Human mobility, which includes large-scale population replacements, during the Neolithic–Bronze Age transition in central Europe likely helped spread technological advancements and cultural practices. Yet,...



Elucidating the fate of the OH-adduct in toluene oxidation under tropospheric boundary layer conditions [Physical Sciences]

2017-09-19T09:06:53-07:00

Ji et al. (1) published a study examining the mechanism of the initial stages of OH-initiated oxidation of toluene. Their results challenge the mechanisms used in atmospheric chemistry models [e.g., Master Chemical Mechanism (MCM) (2)] derived from chamber experiments at atmospheric conditions, and previous experimental (3, 4) and theoretical studies...



Reply to Newland et al.: The dominant phenolic pathway for atmospheric toluene oxidation [Physical Sciences]

2017-09-19T09:06:53-07:00

Ji et al. (1) reassess the atmospheric oxidation mechanism of toluene: Their experimental work shows a larger-than-expected branching ratio for cresols but negligible formation of ring-opening products and is corroborated by theoretical calculations revealing that the phenolic pathway is kinetically and thermodynamically favored over the primary peroxy radical (RO2) formation....



Autoimmune disease variants regulate GSDMB gene expression in human immune cells and whole blood [Biological Sciences]

2017-09-19T09:06:53-07:00

There are four gasdermin (GSDM) proteins, including GSDMA, GSDMB, GSDMC, and GSDMD, in the human genome (1). Genome-wide association studies have reported genetic variants at 17q12.2.1 loci, including GSDMA, GSDMB, and ORDML3 genes, to be associated with kinds of autoimmune diseases, including asthma, type 1 diabetes, inflammatory bowel disease (IBD),...



Reply to HU et al.: On the interpretation of gasdermin-B expression quantitative trait loci data [Biological Sciences]

2017-09-19T09:06:53-07:00

We recently published structural and biochemical studies of gasdermin-B (GSDMB) (1), a protein that regulates the maintenance of the epithelial cell barrier as well as cell proliferation and differentiation processes (2, 3). GSDMB amplification and GSDMB overexpression lead to a poor response to HER2-targeted therapy in HER2-positive breast cancer (4)....



From understanding of color perception to dynamical systems by manifold learning [Applied Mathematics]

2017-09-19T09:06:53-07:00

Comprehending Color Let us start with a seemingly unrelated field to that described in the article by Yair et al. (1) in PNAS. The field of psychophysics deals with the relationships between physical stimuli and mental phenomena. An excellent example is the scientific community’s early efforts to study the human...



Shocking superantigens promote establishment of bacterial infection [Microbiology]

2017-09-19T09:06:53-07:00

Streptococcus pyogenes, also referred to as group A Streptococcus (GAS), is an exclusive human pathogen causing diseases ranging from uncomplicated infections of the throat and skin to severe invasive infections, such as necrotizing fasciitis and streptococcal toxic shock syndrome (STSS). Asymptomatic carriage, particularly in the naso- and oropharyngeal mucosa, is...



Cooperation between hearing and vision in people with cochlear implants [Neuroscience]

2017-09-19T09:06:53-07:00

The cochlear implant (CI) is the single most successful neuroprosthetic device available today, often restoring functional hearing in many of those who were profoundly deaf (1). Unlike traditional hearing aids that serve to amplify ambient sound, the CI bypasses the transduction process and provides direct electrical signals to the nerve...



Reconstruction of normal forms by learning informed observation geometries from data [Applied Mathematics]

2017-09-19T09:06:53-07:00

The discovery of physical laws consistent with empirical observations is at the heart of (applied) science and engineering. These laws typically take the form of nonlinear differential equations depending on parameters; dynamical systems theory provides, through the appropriate normal forms, an “intrinsic” prototypical characterization of the types of dynamical regimes...



Effects of thymic selection on T cell recognition of foreign and tumor antigenic peptides [Biophysics and Computational Biology]

2017-09-19T09:06:53-07:00

The advent of cancer immunotherapy has generated renewed hope for the treatment of many malignancies by introducing a number of novel strategies that exploit various properties of the immune system. These therapies are based on the idea that cytotoxic T lymphocytes (CTLs) directly recognize and respond to tumor-associated neoantigens (TANs)...



A classical view on nonclassical nucleation [Chemistry]

2017-09-19T09:06:53-07:00

Understanding and controlling nucleation is important for many crystallization applications. Calcium carbonate (CaCO3) is often used as a model system to investigate nucleation mechanisms. Despite its great importance in geology, biology, and many industrial applications, CaCO3 nucleation is still a topic of intense discussion, with new pathways for its growth...



Subnational mobility and consumption-based environmental accounting of US corn in animal protein and ethanol supply chains [Sustainability Science]

2017-09-19T09:06:53-07:00

Corn production, and its associated inputs, is a relatively large source of greenhouse gas emissions and uses significant amounts of water and land, thus contributing to climate change, fossil fuel depletion, local air pollutants, and local water scarcity. As large consumers of this corn, corporations in the ethanol and animal...



Self-report captures 27 distinct categories of emotion bridged by continuous gradients [Psychological and Cognitive Sciences]

2017-09-19T09:06:53-07:00

Emotions are centered in subjective experiences that people represent, in part, with hundreds, if not thousands, of semantic terms. Claims about the distribution of reported emotional states and the boundaries between emotion categories—that is, the geometric organization of the semantic space of emotion—have sparked intense debate. Here we introduce a...



North-south polarization of European electricity consumption under future warming [Sustainability Science]

2017-09-19T09:06:54-07:00

There is growing empirical evidence that anthropogenic climate change will substantially affect the electric sector. Impacts will stem both from the supply side—through the mitigation of greenhouse gases—and from the demand side—through adaptive responses to a changing environment. Here we provide evidence of a polarization of both peak load and...



Injectable biomimetic liquid crystalline scaffolds enhance muscle stem cell transplantation [Applied Biological Sciences]

2017-09-19T09:06:54-07:00

Muscle stem cells are a potent cell population dedicated to efficacious skeletal muscle regeneration, but their therapeutic utility is currently limited by mode of delivery. We developed a cell delivery strategy based on a supramolecular liquid crystal formed by peptide amphiphiles (PAs) that encapsulates cells and growth factors within a...



Differential diagnosis of Alzheimer’s disease using spectrochemical analysis of blood [Biochemistry]

2017-09-19T09:06:54-07:00

The progressive aging of the world’s population makes a higher prevalence of neurodegenerative diseases inevitable. The necessity for an accurate, but at the same time, inexpensive and minimally invasive, diagnostic test is urgently required, not only to confirm the presence of the disease but also to discriminate between different types...



Loquacious-PD facilitates Drosophila Dicer-2 cleavage through interactions with the helicase domain and dsRNA [Biochemistry]

2017-09-19T09:06:54-07:00

Loquacious-PD (Loqs-PD) is required for biogenesis of many endogenous siRNAs in Drosophila. In vitro, Loqs-PD enhances the rate of dsRNA cleavage by Dicer-2 and also enables processing of substrates normally refractory to cleavage. Using purified components, and Loqs-PD truncations, we provide a mechanistic basis for Loqs-PD functions. Our studies indicate...



Role of remodeling and spacing factor 1 in histone H2A ubiquitination-mediated gene silencing [Biochemistry]

2017-09-19T09:06:54-07:00

Posttranslational histone modifications play important roles in regulating chromatin-based nuclear processes. Histone H2AK119 ubiquitination (H2Aub) is a prevalent modification and has been primarily linked to gene silencing. However, the underlying mechanism remains largely obscure. Here we report the identification of RSF1 (remodeling and spacing factor 1), a subunit of the...



Binding mechanism and dynamic conformational change of C subunit of PKA with different pathways [Biophysics and Computational Biology]

2017-09-19T09:06:54-07:00

The catalytic subunit of PKA (PKAc) exhibits three major conformational states (open, intermediate, and closed) during the biocatalysis process. Both ATP and substrate/inhibitor can effectively induce the conformational changes of PKAc from open to closed states. Aiming to explore the mechanism of this allosteric regulation, we developed a coarse-grained model...



Osmotaxis in Escherichia coli through changes in motor speed [Biophysics and Computational Biology]

2017-09-19T09:06:54-07:00

Bacterial motility, and in particular repulsion or attraction toward specific chemicals, has been a subject of investigation for over 100 years, resulting in detailed understanding of bacterial chemotaxis and the corresponding sensory network in many bacterial species. For Escherichia coli most of the current understanding comes from the experiments with...



Multiple proteolytic events in caspase-6 self-activation impact conformations of discrete structural regions [Biophysics and Computational Biology]

2017-09-19T09:06:54-07:00

Caspase-6 is critical to the neurodegenerative pathways of Alzheimer’s, Huntington’s, and Parkinson’s diseases and has been identified as a potential molecular target for treatment of neurodegeneration. Thus, understanding the global and regional changes in dynamics and conformation provides insights into the unique properties of caspase-6 that may contribute to achieving...



Structure of the Ebola virus envelope protein MPER/TM domain and its interaction with the fusion loop explains their fusion activity [Biophysics and Computational Biology]

2017-09-19T09:06:54-07:00

Ebolavirus (EBOV), an enveloped filamentous RNA virus causing severe hemorrhagic fever, enters cells by macropinocytosis and membrane fusion in a late endosomal compartment. Fusion is mediated by the EBOV envelope glycoprotein GP, which consists of subunits GP1 and GP2. GP1 binds to cellular receptors, including Niemann-Pick C1 (NPC1) protein, and...



Dual role of mitochondria in producing melatonin and driving GPCR signaling to block cytochrome c release [Cell Biology]

2017-09-19T09:06:54-07:00

G protein-coupled receptors (GPCRs) are classically characterized as cell-surface receptors transmitting extracellular signals into cells. Here we show that central components of a GPCR signaling system comprised of the melatonin type 1 receptor (MT1), its associated G protein, and β-arrestins are on and within neuronal mitochondria. We discovered that the...



Effect of cell cycle arrest on intermediate metabolism in the marine diatom Phaeodactylum tricornutum [Cell Biology]

2017-09-19T09:06:54-07:00

The inhibitor NU 2058 [6-(cyclohexylmethoxy)-9H-purin-2-amine] leads to G1-phase cell cycle arrest in the marine diatom, Phaeodactylum tricornutum, by binding to two cyclin-dependent kinases, CDKA1 and CDKA2. NU 2058 has no effect on photosynthetic attributes, such as Fv/Fm, chlorophyll a/cell, levels of D2 PSII subunits, or RbcL; however, cell cycle arrest...



MicroRNA-277 targets insulin-like peptides 7 and 8 to control lipid metabolism and reproduction in Aedes aegypti mosquitoes [Developmental Biology]

2017-09-19T09:06:54-07:00

Hematophagous female mosquitoes transmit numerous devastating human diseases, including malaria, dengue fever, Zika virus, and others. Because of their obligatory requirement of a vertebrate blood meal for reproduction, these mosquitoes need a lot of energy; therefore, understanding the molecular mechanisms linking metabolism and reproduction is of particular importance. Lipids are...



Escherichia coli responds to environmental changes using enolasic degradosomes and stabilized DicF sRNA to alter cellular morphology [Genetics]

2017-09-19T09:06:54-07:00

Escherichia coli RNase E is an essential enzyme that forms multicomponent ribonucleolytic complexes known as “RNA degradosomes.” These complexes consist of four major components: RNase E, PNPase, RhlB RNA helicase, and enolase. However, the role of enolase in the RNase E/degradosome is not understood. Here, we report that presence of...



CK1{alpha} ablation in keratinocytes induces p53-dependent, sunburn-protective skin hyperpigmentation [Medical Sciences]

2017-09-19T09:06:54-07:00

Casein kinase 1α (CK1α), a component of the β-catenin destruction complex, is a critical regulator of Wnt signaling; its ablation induces both Wnt and p53 activation. To characterize the role of CK1α (encoded by Csnk1a1) in skin physiology, we crossed mice harboring floxed Csnk1a1 with mice expressing K14–Cre–ERT2 to generate...



Mutation in human CLPX elevates levels of {delta}-aminolevulinate synthase and protoporphyrin IX to promote erythropoietic protoporphyria [Medical Sciences]

2017-09-19T09:06:54-07:00

Loss-of-function mutations in genes for heme biosynthetic enzymes can give rise to congenital porphyrias, eight forms of which have been described. The genetic penetrance of the porphyrias is clinically variable, underscoring the role of additional causative, contributing, and modifier genes. We previously discovered that the mitochondrial AAA+ unfoldase ClpX promotes...



Methylation-dependent DNA discrimination in natural transformation of Campylobacter jejuni [Microbiology]

2017-09-19T09:06:54-07:00

Campylobacter jejuni, a leading cause of bacterial gastroenteritis, is naturally competent. Like many competent organisms, C. jejuni restricts the DNA that can be used for transformation to minimize undesirable changes in the chromosome. Although C. jejuni can be transformed by C. jejuni-derived DNA, it is poorly transformed by the same...



Dendritic space-filling requires a neuronal type-specific extracellular permissive signal in Drosophila [Neuroscience]

2017-09-19T09:06:54-07:00

Neurons sometimes completely fill available space in their receptive fields with evenly spaced dendrites to uniformly sample sensory or synaptic information. The mechanisms that enable neurons to sense and innervate all space in their target tissues are poorly understood. Using Drosophila somatosensory neurons as a model, we show that heparan...



Schwann cells use TAM receptor-mediated phagocytosis in addition to autophagy to clear myelin in a mouse model of nerve injury [Neuroscience]

2017-09-19T09:06:54-07:00

Ineffective myelin debris clearance is a major factor contributing to the poor regenerative ability of the central nervous system. In stark contrast, rapid clearance of myelin debris from the injured peripheral nervous system (PNS) is one of the keys to this system’s remarkable regenerative capacity, but the molecular mechanisms driving...



Efficient stimulus-secretion coupling at ribbon synapses requires RIM-binding protein tethering of L-type Ca2+ channels [Neuroscience]

2017-09-19T09:06:54-07:00

Fast neurotransmitter release from ribbon synapses via Ca2+-triggered exocytosis requires tight coupling of L-type Ca2+ channels to release-ready synaptic vesicles at the presynaptic active zone, which is localized at the base of the ribbon. Here, we used genetic, electrophysiological, and ultrastructural analyses to probe the architecture of ribbon synapses by...



Dissection of the Drosophila neuropeptide F circuit using a high-throughput two-choice assay [Neuroscience]

2017-09-19T09:06:54-07:00

In their classic experiments, Olds and Milner showed that rats learn to lever press to receive an electric stimulus in specific brain regions. This led to the identification of mammalian reward centers. Our interest in defining the neuronal substrates of reward perception in the fruit fly Drosophila melanogaster prompted us...



Discovery of peptide ligands through docking and virtual screening at nicotinic acetylcholine receptor homology models [Pharmacology]

2017-09-19T09:06:54-07:00

Venom peptide toxins such as conotoxins play a critical role in the characterization of nicotinic acetylcholine receptor (nAChR) structure and function and have potential as nervous system therapeutics as well. However, the lack of solved structures of conotoxins bound to nAChRs and the large size of these peptides are barriers...



A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments [Plant Biology]

2017-09-19T09:06:54-07:00

Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because—in nature—photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report...



Receptor-mediated chitin perception in legume roots is functionally separable from Nod factor perception [Plant Biology]

2017-09-19T09:06:54-07:00

The ability of root cells to distinguish mutualistic microbes from pathogens is crucial for plants that allow symbiotic microorganisms to infect and colonize their internal root tissues. Here we show that Lotus japonicus and Medicago truncatula possess very similar LysM pattern-recognition receptors, LjLYS6/MtLYK9 and MtLYR4, enabling root cells to separate...



Rome’s urban history inferred from Pb-contaminated waters trapped in its ancient harbor basins [Anthropology]

2017-09-19T09:06:53-07:00

Heavy metals from urban runoff preserved in sedimentary deposits record long-term economic and industrial development via the expansion and contraction of a city’s infrastructure. Lead concentrations and isotopic compositions measured in the sediments of the harbor of Ostia—Rome’s first harbor—show that lead pipes used in the water supply networks of...



Female exogamy and gene pool diversification at the transition from the Final Neolithic to the Early Bronze Age in central Europe [Anthropology]

2017-09-19T09:06:53-07:00

Human mobility has been vigorously debated as a key factor for the spread of bronze technology and profound changes in burial practices as well as material culture in central Europe at the transition from the Neolithic to the Bronze Age. However, the relevance of individual residential changes and their importance...



Mesoscale martensitic transformation in single crystals of topological defects [Applied Physical Sciences]

2017-09-19T09:06:53-07:00

Liquid-crystal blue phases (BPs) are highly ordered at two levels. Molecules exhibit orientational order at nanometer length scales, while chirality leads to ordered arrays of double-twisted cylinders over micrometer scales. Past studies of polycrystalline BPs were challenged by the existence of grain boundaries between randomly oriented crystalline nanodomains. Here, the...



Ultrafast fluorescent decay induced by metal-mediated dipole-dipole interaction in two-dimensional molecular aggregates [Applied Physical Sciences]

2017-09-19T09:06:53-07:00

Two-dimensional molecular aggregate (2DMA), a thin sheet of strongly interacting dipole molecules self-assembled at close distance on an ordered lattice, is a fascinating fluorescent material. It is distinctively different from the conventional (single or colloidal) dye molecules and quantum dots. In this paper, we verify that when a 2DMA is...



Molecular mechanism of water reorientational slowing down in concentrated ionic solutions [Biochemistry]

2017-09-19T09:06:53-07:00

Water dynamics in concentrated ionic solutions plays an important role in a number of material and energy conversion processes such as the charge transfer at the electrolyte–electrode interface in aqueous rechargeable ion batteries. One long-standing puzzle is that all electrolytes, regardless of their “structure-making/breaking” nature, make water rotate slower at...



Stachel-independent modulation of GPR56/ADGRG1 signaling by synthetic ligands directed to its extracellular region [Biochemistry]

2017-09-19T09:06:53-07:00

Adhesion G protein-coupled receptors (aGPCRs) play critical roles in diverse biological processes, including neurodevelopment and cancer progression. aGPCRs are characterized by large and diverse extracellular regions (ECRs) that are autoproteolytically cleaved from their membrane-embedded signaling domains. Although ECRs regulate receptor function, it is not clear whether ECRs play a direct...



Epigenetic control via allosteric regulation of mammalian protein arginine methyltransferases [Biochemistry]

2017-09-19T09:06:53-07:00

Arginine methylation on histones is a central player in epigenetics and in gene activation and repression. Protein arginine methyltransferase (PRMT) activity has been implicated in stem cell pluripotency, cancer metastasis, and tumorigenesis. The expression of one of the nine mammalian PRMTs, PRMT5, affects the levels of symmetric dimethylarginine (SDMA) at...



Molecular mechanism of substrate recognition and transport by the AtSWEET13 sugar transporter [Biophysics and Computational Biology]

2017-09-19T09:06:53-07:00

Sugar Will Eventually be Exported Transporters (SWEETs) are recently identified sugar transporters that can discriminate and transport di- or monosaccharides across a membrane following the concentration gradient. SWEETs play key roles in plant biological processes, such as pollen nutrition, nectar secretion, seed filling, and phloem loading. SWEET13 from Arabidopsis thaliana...



Discrete modes of social information processing predict individual behavior of fish in a group [Biophysics and Computational Biology]

2017-09-19T09:06:53-07:00

Individual computations and social interactions underlying collective behavior in groups of animals are of great ethological, behavioral, and theoretical interest. While complex individual behaviors have successfully been parsed into small dictionaries of stereotyped behavioral modes, studies of collective behavior largely ignored these findings; instead, their focus was on inferring single,...



Thyroid hormone receptor beta and NCOA4 regulate terminal erythrocyte differentiation [Cell Biology]

2017-09-19T09:06:53-07:00

An effect of thyroid hormone (TH) on erythropoiesis has been known for more than a century but the molecular mechanism(s) by which TH affects red cell formation is still elusive. Here we demonstrate an essential role of TH during terminal human erythroid cell differentiation; specific depletion of TH from the...



Smad7 enables STAT3 activation and promotes pluripotency independent of TGF-{beta} signaling [Cell Biology]

2017-09-19T09:06:53-07:00

Smad7 is a negative feedback product of TGF-β superfamily signaling and fine tunes a plethora of pleiotropic responses induced by TGF-β ligands. However, its noncanonical functions independent of TGF-β signaling remain to be elucidated. Here, we show that Smad7 activates signal transducers and activators of transcription 3 (STAT3) signaling in...



Proteoliposome-based full-length ZnT8 self-antigen for type 1 diabetes diagnosis on a plasmonic platform [Chemistry]

2017-09-19T09:06:53-07:00

Identified as a major biomarker for type 1 diabetes (T1D) diagnosis, zinc transporter 8 autoantibody (ZnT8A) has shown promise for staging disease risk and disease diagnosis. However, existing assays for ZnT8 autoantibody (ZnT8A) are limited to detection by soluble domains of ZnT8, owing to difficulties in maintaining proper folding of...



Maximal aggregation of polynomial dynamical systems [Computer Sciences]

2017-09-19T09:06:53-07:00

Ordinary differential equations (ODEs) with polynomial derivatives are a fundamental tool for understanding the dynamics of systems across many branches of science, but our ability to gain mechanistic insight and effectively conduct numerical evaluations is critically hindered when dealing with large models. Here we propose an aggregation technique that rests...



Cbf{beta} governs osteoblast-adipocyte lineage commitment through enhancing {beta}-catenin signaling and suppressing adipogenesis gene expression [Developmental Biology]

2017-09-19T09:06:53-07:00

The mechanism underlying how transcription factors regulate mesenchymal stem cell lineage commitment remains unclear. To determine the role of core-binding factor subunit beta (Cbfβ) in osteoblast lineage commitment, we generated three mouse models by deleting Cbfβ at different osteoblast lineage stages. We demonstrated that the Cbfβf/fPrx1-Cre, Cbfβf/fCol2α1-Cre, and Cbfβf/fOsx-Cre mice...



First critical repressive H3K27me3 marks in embryonic stem cells identified using designed protein inhibitor [Developmental Biology]

2017-09-19T09:06:53-07:00

The polycomb repressive complex 2 (PRC2) histone methyltransferase plays a central role in epigenetic regulation in development and in cancer, and hence to interrogate its role in a specific developmental transition, methods are needed for disrupting function of the complex with high temporal and spatial precision. The catalytic and substrate...



An epigenetic switch repressing Tet1 in gonadotropes activates the reproductive axis [Developmental Biology]

2017-09-19T09:06:53-07:00

The TET enzymes catalyze conversion of 5-methyl cytosine (5mC) to 5-hydroxymethyl cytosine (5hmC) and play important roles during development. TET1 has been particularly well-studied in pluripotent stem cells, but Tet1-KO mice are viable, and the most marked defect is abnormal ovarian follicle development, resulting in impaired fertility. We hypothesized that...



CNS-resident progenitors direct the vascularization of neighboring tissues [Developmental Biology]

2017-09-19T09:06:53-07:00

Organ growth requires the coordinated invasion and expansion of blood vessel networks directed by tissue-resident cells and morphogenetic cues. A striking example of this intercellular communication is the vascularization of the central nervous system (CNS), which is driven by neuronal progenitors, including neuroepithelial cells and radial glia. Although the importance...



Endodermal germ-layer formation through active actin-driven migration triggered by N-cadherin [Developmental Biology]

2017-09-19T09:06:53-07:00

Germ-layer formation during gastrulation is both a fundamental step of development and a paradigm for tissue formation and remodeling. However, the cellular and molecular basis of germ-layer segregation is poorly understood, mostly because of the lack of direct in vivo observations. We used mosaic zebrafish embryos to investigate the formation...



Beyond sixfold coordinated Si in SiO2 glass at ultrahigh pressures [Earth, Atmospheric, and Planetary Sciences]

2017-09-19T09:06:53-07:00

We investigated the structure of SiO2 glass up to 172 GPa using high-energy X-ray diffraction. The combination of a multichannel collimator with diamond anvil cells enabled the measurement of structural changes in silica glass with total X-ray diffraction to previously unachievable pressures. We show that SiO2 first undergoes a change...



Abrupt climate changes during Termination III in Southern Europe [Earth, Atmospheric, and Planetary Sciences]

2017-09-19T09:06:53-07:00

The Late Quaternary glacial–interglacial transitions represent the highest amplitude climate changes over the last million years. Unraveling the sequence of events and feedbacks at Termination III (T-III), including potential abrupt climate reversals similar to those of the last Termination, has been particularly challenging due to the scarcity of well-dated records...



Active molecular iodine photochemistry in the Arctic [Earth, Atmospheric, and Planetary Sciences]

2017-09-19T09:06:53-07:00

During springtime, the Arctic atmospheric boundary layer undergoes frequent rapid depletions in ozone and gaseous elemental mercury due to reactions with halogen atoms, influencing atmospheric composition and pollutant fate. Although bromine chemistry has been shown to initiate ozone depletion events, and it has long been hypothesized that iodine chemistry may...



Eighty years of food-web response to interannual variation in discharge recorded in river diatom frustules from an ocean sediment core [Ecology]

2017-09-19T09:06:53-07:00

Little is known about the importance of food-web processes as controls of river primary production due to the paucity of both long-term studies and of depositional environments which would allow retrospective fossil analysis. To investigate how freshwater algal production in the Eel River, northern California, varied over eight decades, we...



Biodiversity promotes primary productivity and growing season lengthening at the landscape scale [Ecology]

2017-09-19T09:06:53-07:00

Experiments have shown positive biodiversity-ecosystem functioning (BEF) relationships in small plots with model communities established from species pools typically comprising few dozen species. Whether patterns found can be extrapolated to complex, nonexperimental, real-world landscapes that provide ecosystem services to humans remains unclear. Here, we combine species inventories from a large-scale...



Opinion: Why we need an international agreement on marine plastic pollution [Environmental Sciences]

2017-09-19T09:06:53-07:00

Plastic pollution is strewn across beaches and in oceans, bays, and estuaries. Tiny particles of plastic debris (often called microplastics) are so pervasive in aquatic ecosystems that we find them in seafood (1) and table salt (2). Marine organisms ingest or are entangled by plastic, sometimes with fatal consequences. Research...



Petroleum dynamics in the sea and influence of subsea dispersant injection during Deepwater Horizon [Environmental Sciences]

2017-09-19T09:06:53-07:00

During the Deepwater Horizon disaster, a substantial fraction of the 600,000–900,000 tons of released petroleum liquid and natural gas became entrapped below the sea surface, but the quantity entrapped and the sequestration mechanisms have remained unclear. We modeled the buoyant jet of petroleum liquid droplets, gas bubbles, and entrained seawater,...



Synchronous volcanic eruptions and abrupt climate change ~17.7 ka plausibly linked by stratospheric ozone depletion [Environmental Sciences]

2017-09-19T09:06:53-07:00

Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts....



Identification of individuals by trait prediction using whole-genome sequencing data [Genetics]

2017-09-19T09:06:53-07:00

Prediction of human physical traits and demographic information from genomic data challenges privacy and data deidentification in personalized medicine. To explore the current capabilities of phenotype-based genomic identification, we applied whole-genome sequencing, detailed phenotyping, and statistical modeling to predict biometric traits in a cohort of 1,061 participants of diverse ancestry....



Increasing the breadth and potency of response to the seasonal influenza virus vaccine by immune complex immunization [Immunology and Inflammation]

2017-09-19T09:06:53-07:00

The main barrier to reduction of morbidity caused by influenza is the absence of a vaccine that elicits broad protection against different virus strains. Studies in preclinical models of influenza virus infections have shown that antibodies alone are sufficient to provide broad protection against divergent virus strains in vivo. Here,...



Gallbladder-derived surfactant protein D regulates gut commensal bacteria for maintaining intestinal homeostasis [Immunology and Inflammation]

2017-09-19T09:06:53-07:00

The commensal microbiota within the gastrointestinal tract is essential in maintaining homeostasis. Indeed, dysregulation in the repertoire of microbiota can result in the development of intestinal immune–inflammatory diseases. Further, this immune regulation by gut microbiota is important systemically, impacting health and disease of organ systems beyond the local environment of...



Localized CD47 blockade enhances immunotherapy for murine melanoma [Immunology and Inflammation]

2017-09-19T09:06:53-07:00

CD47 is an antiphagocytic ligand broadly expressed on normal and malignant tissues that delivers an inhibitory signal through the receptor signal regulatory protein alpha (SIRPα). Inhibitors of the CD47–SIRPα interaction improve antitumor antibody responses by enhancing antibody-dependent cellular phagocytosis (ADCP) in xenograft models. Endogenous expression of CD47 on a variety...



Treg-specific IL-27R{alpha} deletion uncovers a key role for IL-27 in Treg function to control autoimmunity [Immunology and Inflammation]

2017-09-19T09:06:53-07:00

Dysregulated Foxp3+ Treg functions result in uncontrolled immune activation and autoimmunity. Therefore, identifying cellular factors modulating Treg functions is an area of great importance. Here, using Treg-specific Il27ra−/− mice, we report that IL-27 signaling in Foxp3+ Tregs is essential for Tregs to control autoimmune inflammation in the central nervous system...



Combined circulating tumor DNA and protein biomarker-based liquid biopsy for the earlier detection of pancreatic cancers [Medical Sciences]

2017-09-19T09:06:53-07:00

The earlier diagnosis of cancer is one of the keys to reducing cancer deaths in the future. Here we describe our efforts to develop a noninvasive blood test for the detection of pancreatic ductal adenocarcinoma. We combined blood tests for KRAS gene mutations with carefully thresholded protein biomarkers to determine...



CDK8/19 Mediator kinases potentiate induction of transcription by NF{kappa}B [Medical Sciences]

2017-09-19T09:06:53-07:00

The nuclear factor-κB (NFκB) family of transcription factors has been implicated in inflammatory disorders, viral infections, and cancer. Most of the drugs that inhibit NFκB show significant side effects, possibly due to sustained NFκB suppression. Drugs affecting induced, but not basal, NFκB activity may have the potential to provide therapeutic...



Nitric oxide blocks the development of the human parasite Schistosoma japonicum [Medical Sciences]

2017-09-19T09:06:53-07:00

Human schistosomiasis, caused by Schistosoma species, is a major public health problem affecting more than 700 million people in 78 countries, with over 40 mammalian host reservoir species complicating the transmission ecosystem. The primary cause of morbidity is considered to be granulomas induced by fertilized eggs of schistosomes in the...



Detection of immune responses after immunotherapy in glioblastoma using PET and MRI [Medical Sciences]

2017-09-19T09:06:53-07:00

Contrast-enhanced MRI is typically used to follow treatment response and progression in patients with glioblastoma (GBM). However, differentiating tumor progression from pseudoprogression remains a clinical dilemma largely unmitigated by current advances in imaging techniques. Noninvasive imaging techniques capable of distinguishing these two conditions could play an important role in the...



Nasopharyngeal infection by Streptococcus pyogenes requires superantigen-responsive V{beta}-specific T cells [Microbiology]

2017-09-19T09:06:53-07:00

The globally prominent pathogen Streptococcus pyogenes secretes potent immunomodulatory proteins known as superantigens (SAgs), which engage lateral surfaces of major histocompatibility class II molecules and T-cell receptor (TCR) β-chain variable domains (Vβs). These interactions result in the activation of numerous Vβ-specific T cells, which is the defining activity of a...



A trans-acting leader RNA from a Salmonella virulence gene [Microbiology]

2017-09-19T09:06:53-07:00

Bacteria use flagella to move toward nutrients, find its host, or retract from toxic substances. Because bacterial flagellum is one of the ligands that activate the host innate immune system, its synthesis should be tightly regulated during host infection, which is largely unknown. Here, we report that a bacterial leader...



Virulence protein VirD5 of Agrobacterium tumefaciens binds to kinetochores in host cells via an interaction with Spt4 [Microbiology]

2017-09-19T09:06:53-07:00

The bacterium Agrobacterium tumefaciens causes crown gall tumor formation in plants. During infection the bacteria translocate an oncogenic piece of DNA (transferred DNA, T-DNA) into plant cells at the infection site. A number of virulence proteins are cotransported into host cells concomitantly with the T-DNA to effectuate transformation. Using yeast...



Dorsolateral prefrontal cortex GABA deficit in older adults with sleep-disordered breathing [Neuroscience]

2017-09-19T09:06:53-07:00

Sleep-disordered breathing (SDB) is a common disorder in aging that is associated with cognitive decline, including significant executive dysfunction, for which the neurobiological underpinnings remain poorly understood. Using proton magnetic resonance spectroscopy (1H MRS), this study assessed whether dysregulation of the homeostatic balance of the major inhibitory and excitatory amino...



Adaptive benefit of cross-modal plasticity following cochlear implantation in deaf adults [Neuroscience]

2017-09-19T09:06:53-07:00

It has been suggested that visual language is maladaptive for hearing restoration with a cochlear implant (CI) due to cross-modal recruitment of auditory brain regions. Rehabilitative guidelines therefore discourage the use of visual language. However, neuroscientific understanding of cross-modal plasticity following cochlear implantation has been restricted due to incompatibility between...



Temporal binding function of dorsal CA1 is critical for declarative memory formation [Neuroscience]

2017-09-19T09:06:53-07:00

Temporal binding, the process that enables association between discontiguous stimuli in memory, and relational organization, a process that enables the flexibility of declarative memories, are both hippocampus-dependent and decline in aging. However, how these two processes are related in supporting declarative memory formation and how they are compromised in age-related...



Prenatal neurogenesis induction therapy normalizes brain structure and function in Down syndrome mice [Neuroscience]

2017-09-19T09:06:53-07:00

Down syndrome (DS) caused by trisomy of chromosome 21 is the most common genetic cause of intellectual disability. Although the prenatal diagnosis of DS has become feasible, there are no therapies available for the rescue of DS-related neurocognitive impairment. A growth inducer newly identified in our screen of neural stem...



EIN2 mediates direct regulation of histone acetylation in the ethylene response [Plant Biology]

2017-09-19T09:06:53-07:00

Ethylene gas is essential for developmental processes and stress responses in plants. Although the membrane-bound protein EIN2 is critical for ethylene signaling, the mechanism by which the ethylene signal is transduced remains largely unknown. Here we show the levels of H3K14Ac and H3K23Ac are correlated with the levels of EIN2...



Combinatorial interaction network of abscisic acid receptors and coreceptors from Arabidopsis thaliana [Plant Biology]

2017-09-19T09:06:53-07:00

The phytohormone abscisic acid (ABA) is induced in response to abiotic stress to mediate plant acclimation to environmental challenge. Key players of the ABA-signaling pathway are the ABA-binding receptors (RCAR/PYR1/PYL), which, together with a plant-specific subclade of protein phosphatase 2C (PP2C), form functional holoreceptors. The Arabidopsis genome encodes nine PP2C...



Belief in free will affects causal attributions when ȷudging others’ behavior [Psychological and Cognitive Sciences]

2017-09-19T09:06:53-07:00

Free will is a cornerstone of our society, and psychological research demonstrates that questioning its existence impacts social behavior. In six studies, we tested whether believing in free will is related to the correspondence bias, which reflects people’s automatic tendency to overestimate the influence of internal as compared to external...



Lawful relation between perceptual bias and discriminability [Psychological and Cognitive Sciences]

2017-09-19T09:06:53-07:00

Perception of a stimulus can be characterized by two fundamental psychophysical measures: how well the stimulus can be discriminated from similar ones (discrimination threshold) and how strongly the perceived stimulus value deviates on average from the true stimulus value (perceptual bias). We demonstrate that perceptual bias and discriminability, as functions...



Redefining community based on place attachment in a connected world [Sustainability Science]

2017-09-19T09:06:53-07:00

The concept of community is often used in environmental policy to foster environmental stewardship and public participation, crucial prerequisites of effective management. However, prevailing conceptualizations of community based on residential location or resource use are limited with respect to their utility as surrogates for communities of shared environment-related interests, and...



Global transcriptional regulatory network for Escherichia coli robustly connects gene expression to transcription factor activities [Systems Biology]

2017-09-19T09:06:53-07:00

Transcriptional regulatory networks (TRNs) have been studied intensely for >25 y. Yet, even for the Escherichia coli TRN—probably the best characterized TRN—several questions remain. Here, we address three questions: (i) How complete is our knowledge of the E. coli TRN; (ii) how well can we predict gene expression using this...



Correction for Harris et al., Young children communicate their ignorance and ask questions [Correction]

2017-09-19T09:06:54-07:00

COLLOQUIUM Correction for “Young children communicate their ignorance and ask questions,” by Paul L. Harris, Deborah T. Bartz, and Meredith L. Rowe, which was first published July 25, 2017; 10.1073/pnas.1620745114 (Proc Natl Acad Sci USA 114:7884–7891). The authors note that on page 7887, right column, second full paragraph, lines 9–11,...



Correction for Schuth et al., Effective intermediate-spin iron in O2-transporting heme proteins [Correction]

2017-09-19T09:06:54-07:00

BIOPHYSICS AND COMPUTATIONAL BIOLOGY Correction for “Effective intermediate-spin iron in O2-transporting heme proteins,” by Nils Schuth, Stefan Mebs, Dennis Huwald, Pierre Wrzolek, Matthias Schwalbe, Anja Hemschemeier, and Michael Haumann, which was first published July 24, 2017; 10.1073/pnas.1706527114 (Proc Natl Acad Sci USA 114:8556–8561). The authors note that Fig. 6 appeared...



Correction for KonDo et al., Toll ligand Spatzle3 controls melanization in the stripe pattern formation in caterpillars [Correction]

2017-09-19T09:06:54-07:00

GENETICS Correction for “Toll ligand Spätzle3 controls melanization in the stripe pattern formation in caterpillars,” by Yûsuke KonDo, Shinichi Yoda, Takayuki Mizoguchi, Toshiya Ando, Junichi Yamaguchi, Kimiko Yamamoto, Yutaka Banno, and Haruhiko Fujiwara, which was first published July 17, 2017; 10.1073/pnas.1707896114 (Proc Natl Acad Sci USA 114:8336–8341). The authors note...