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Preview: Proceedings of the National Academy of Sciences recent issues

Proceedings of the National Academy of Sciences recent issues



Proceedings of the National Academy of Sciences RSS feed -- recent issues



 



In This Issue [This Week in PNAS]

2017-07-25T09:25:12-07:00

Self-organization in biological systems Dislodged mussel on sandy sediment. Self-organized systems create patterns resulting from interactions between components. Mónica López Pereira et al. (pp. 7975–7980) evaluated intraspecific interference-driven self-organization in sunflower stands. The authors cultivated sunflower plants in rows at the typical commercial density of 5.1 plants per m2 and...



Reappraisal of dioxygen binding in NOV1 crystal structures [Biological Sciences]

2017-07-25T09:25:13-07:00

McAndrew et al. (1) report the crystal structure of NOV1, a stilbene-cleaving carotenoid cleavage oxygenase (CCO), in substrate-free and substrate/product-bound forms, all of which with dioxygen (O2) bound to the nonheme iron center of the enzyme. In mononuclear nonheme iron enzymes studied to date, the Fe–O2 interaction is strongly promoted...



Reply to Kiser: Dioxygen binding in NOV1 crystal structures [Biological Sciences]

2017-07-25T09:25:13-07:00

In PNAS (1) Kiser has expressed some skepticism about the identity of the active-site dioxygen molecule and suggests that the density is better modeled with two water molecules at partial occupancy. In response, we have performed an extended analysis with the following results. There are currently 321 entries for proteins...



Linking brain networks and behavioral variability to different types of mind-wandering [Biological Sciences]

2017-07-25T09:25:13-07:00

Research focusing on mind-wandering (MW) has consistently shown that this mental state is accompanied by variable, error-prone behavior and increased activity within the default mode network (DMN) and the frontoparietal control network (FPN) (1–6). Given that the DMN has been implicated in internal mentation such as future planning or self-referential...



Reply to Csifcsak and Mittner: Fitting data to neural models of mind-wandering [Biological Sciences]

2017-07-25T09:25:13-07:00

We recently provided evidence for a nonunitary account of default mode network (DMN) function, because DMN activity was associated with greater mind-wandering (MW) on the one hand, but with behavioral stability on the other (1). Csifcsák and Mittner (2) suggest that their nonunitary model of MW could explain these results....



Profile of Stephen C. West [Profiles]

2017-07-25T09:25:13-07:00

Biochemist Stephen West attended university to avoid a lifetime of working with fish. Growing up near Hull, Yorkshire, England, West saw the swollen hands of the dock workers who spent their days filleting fish under ice-cold water. His father, a fish buyer, would come home with his arms covered in...



Different phosphodiesterases (PDEs) regulate distinct phosphoproteomes during cAMP signaling [Pharmacology]

2017-07-25T09:25:13-07:00

Sixty years ago, Sutherland and Rall identified cAMP as the first second messenger involved in cell–cell communication (reviewed in ref. 1). For many years, Sutherland had been interested in understanding how hormones, such as catecholamines, released by one cell type could alter the characteristics of a target cell because hormones...



Uncoupling protein 1 controls reactive oxygen species in brown adipose tissue [Biochemistry]

2017-07-25T09:25:13-07:00

Brown adipose tissue (BAT) is an organ specialized to fuel nonshivering thermogenesis for the defense of high body temperature of many eutherian mammals in the cold. Cold-induced sympathetic stimulation of brown adipocytes activates lipolysis, glucose uptake, and mitochondrial biogenesis, with the mitochondrial biogenesis providing a powerful cellular engine for heat...



Regular patterns link individual behavior to population persistence [Ecology]

2017-07-25T09:25:13-07:00

Resisting and recovering from disturbances is a necessity for most species. The strategy is sometimes collective, depending on the aggregation of interacting individuals into regular patterns. However, relating patterns of abundance across scales to both individual behavior and population persistence remains a major challenge for ecology. Such patterns are found...



Big-time insights from a tiny bird fossil [Evolution]

2017-07-25T09:25:13-07:00

Birds are among the most diverse and widely distributed groups of vertebrate animals. There are well over 10,000 recognized species alive today, occupying virtually every subaerial ecosystem (1). The amazing breadth of extant bird diversity is manifested in dizzying varieties of forms, colors, and lifestyles, ranging from iridescent, hovering, nectar-feeding...



Anti-inflammatory {omega}-3 endocannabinoid epoxides [Biochemistry]

2017-07-25T09:25:13-07:00

Clinical studies suggest that diets rich in ω-3 polyunsaturated fatty acids (PUFAs) provide beneficial anti-inflammatory effects, in part through their conversion to bioactive metabolites. Here we report on the endogenous production of a previously unknown class of ω-3 PUFA–derived lipid metabolites that originate from the crosstalk between endocannabinoid and cytochrome...



Structural insights into lipoprotein N-acylation by Escherichia coli apolipoprotein N-acyltransferase [Biochemistry]

2017-07-25T09:25:13-07:00

Gram-negative bacteria express a diverse array of lipoproteins that are essential for various aspects of cell growth and virulence, including nutrient uptake, signal transduction, adhesion, conjugation, sporulation, and outer membrane protein folding. Lipoprotein maturation requires the sequential activity of three enzymes that are embedded in the cytoplasmic membrane. First, phosphatidylglycerol:prolipoprotein...



G9a coordinates with the RPA complex to promote DNA damage repair and cell survival [Biochemistry]

2017-07-25T09:25:13-07:00

Histone methyltransferase G9a has critical roles in promoting cancer-cell growth and gene suppression, but whether it is also associated with the DNA damage response is rarely studied. Here, we report that loss of G9a impairs DNA damage repair and enhances the sensitivity of cancer cells to radiation and chemotherapeutics. In...



Size and mobility of lipid domains tuned by geometrical constraints [Biophysics and Computational Biology]

2017-07-25T09:25:13-07:00

In the plasma membrane of eukaryotic cells, proteins and lipids are organized in clusters, the latter ones often called lipid domains or “lipid rafts.” Recent findings highlight the dynamic nature of such domains and the key role of membrane geometry and spatial boundaries. In this study, we used porous substrates...



Functional characterization of human pluripotent stem cell-derived arterial endothelial cells [Cell Biology]

2017-07-25T09:25:13-07:00

Here, we report the derivation of arterial endothelial cells from human pluripotent stem cells that exhibit arterial-specific functions in vitro and in vivo. We combine single-cell RNA sequencing of embryonic mouse endothelial cells with an EFNB2-tdTomato/EPHB4-EGFP dual reporter human embryonic stem cell line to identify factors that regulate arterial endothelial...



TRPM7 senses oxidative stress to release Zn2+ from unique intracellular vesicles [Cell Biology]

2017-07-25T09:25:13-07:00

TRPM7 (transient receptor potential cation channel subfamily M member 7) regulates gene expression and stress-induced cytotoxicity and is required in early embryogenesis through organ development. Here, we show that the majority of TRPM7 is localized in abundant intracellular vesicles. These vesicles (M7Vs) are distinct from endosomes, lysosomes, and other familiar...



Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines [Ecology]

2017-07-25T09:25:13-07:00

The population extinction pulse we describe here shows, from a quantitative viewpoint, that Earth’s sixth mass extinction is more severe than perceived when looking exclusively at species extinctions. Therefore, humanity needs to address anthropogenic population extirpation and decimation immediately. That conclusion is based on analyses of the numbers and degrees...



Continuous immunotypes describe human immune variation and predict diverse responses [Immunology and Inflammation]

2017-07-25T09:25:13-07:00

The immune system consists of many specialized cell populations that communicate with each other to achieve systemic immune responses. Our analyses of various measured immune cell population frequencies in healthy humans and their responses to diverse stimuli show that human immune variation is continuous in nature, rather than characterized by...



Influenza infection triggers disease in a genetic model of experimental autoimmune encephalomyelitis [Immunology and Inflammation]

2017-07-25T09:25:13-07:00

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. Most MS patients experience periods of symptom exacerbation (relapses) followed by periods of partial recovery (remission). Interestingly, upper-respiratory viral infections increase the risk for relapse. Here, we used an autoimmune-prone T-cell receptor transgenic mouse (2D2) and a mouse-adapted...



Suboptimal T-cell receptor signaling compromises protein translation, ribosome biogenesis, and proliferation of mouse CD8 T cells [Immunology and Inflammation]

2017-07-25T09:25:13-07:00

Global transcriptomic and proteomic analyses of T cells have been rich sources of unbiased data for understanding T-cell activation. Lack of full concordance of these datasets has illustrated that important facets of T-cell activation are controlled at the level of translation. We undertook translatome analysis of CD8 T-cell activation, combining...



Loss-of-function mutation in Mirta22/Emc10 rescues specific schizophrenia-related phenotypes in a mouse model of the 22q11.2 deletion [Medical Sciences]

2017-07-25T09:25:13-07:00

Identification of protective loss-of-function (LoF) mutations holds great promise for devising novel therapeutic interventions, although it faces challenges due to the scarcity of protective LoF alleles in the human genome. Exploiting the detailed mechanistic characterization of animal models of validated disease mutations offers an alternative. Here, we provide insights into...



Combined epigenetic and differentiation-based treatment inhibits neuroblastoma tumor growth and links HIF2{alpha} to tumor suppression [Medical Sciences]

2017-07-25T09:25:13-07:00

Neuroblastoma is a pediatric cancer characterized by variable outcomes ranging from spontaneous regression to life-threatening progression. High-risk neuroblastoma patients receive myeloablative chemotherapy with hematopoietic stem-cell transplant followed by adjuvant retinoid differentiation treatment. However, the overall survival remains low; hence, there is an urgent need for alternative therapeutic approaches. One feature...



Multiplexed RNAi therapy against brain tumor-initiating cells via lipopolymeric nanoparticle infusion delays glioblastoma progression [Medical Sciences]

2017-07-25T09:25:13-07:00

Brain tumor-initiating cells (BTICs) have been identified as key contributors to therapy resistance, recurrence, and progression of diffuse gliomas, particularly glioblastoma (GBM). BTICs are elusive therapeutic targets that reside across the blood–brain barrier, underscoring the urgent need to develop novel therapeutic strategies. Additionally, intratumoral heterogeneity and adaptations to therapeutic pressure...



Stem cell-released oncolytic herpes simplex virus has therapeutic efficacy in brain metastatic melanomas [Medical Sciences]

2017-07-25T09:25:13-07:00

The recent Food and Drug Administration approval of immunogenic oncolytic virus (OV) has opened a new era in the treatment of advanced melanoma; however, approximately 50% of patients with melanoma develop brain metastasis, and currently there are no beneficial treatment options for such patients. To model the progression of metastases...



Intestinal virome changes precede autoimmunity in type I diabetes-susceptible children [Medical Sciences]

2017-07-25T09:25:14-07:00

Viruses have long been considered potential triggers of autoimmune diseases. Here we defined the intestinal virome from birth to the development of autoimmunity in children at risk for type 1 diabetes (T1D). A total of 220 virus-enriched preparations from serially collected fecal samples from 11 children (cases) who developed serum...



Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation [Microbiology]

2017-07-25T09:25:14-07:00

During sporulation, the filamentous bacteria Streptomyces undergo a massive cell division event in which the synthesis of ladders of sporulation septa convert multigenomic hyphae into chains of unigenomic spores. This process requires cytokinetic Z-rings formed by the bacterial tubulin homolog FtsZ, and the stabilization of the newly formed Z-rings is...



Bifunctionality of a biofilm matrix protein controlled by redox state [Microbiology]

2017-07-25T09:25:14-07:00

Biofilms are communities of microbial cells that are encapsulated within a self-produced polymeric matrix. The matrix is critical to the success of biofilms in diverse habitats; however, many details of the composition, structure, and function remain enigmatic. Biofilms formed by the Gram-positive bacterium Bacillus subtilis depend on the production of...



Attention model of binocular rivalry [Neuroscience]

2017-07-25T09:25:14-07:00

When the corresponding retinal locations in the two eyes are presented with incompatible images, a stable percept gives way to perceptual alternations in which the two images compete for perceptual dominance. As perceptual experience evolves dynamically under constant external inputs, binocular rivalry has been used for studying intrinsic cortical computations...



Acetylcholine-producing NK cells attenuate CNS inflammation via modulation of infiltrating monocytes/macrophages [Neuroscience]

2017-07-25T09:25:14-07:00

The nonneural cholinergic system of immune cells is pivotal for the maintenance of immunological homeostasis. Here we demonstrate the expression of choline acetyltransferase (ChAT) and cholinergic enzymes in murine natural killer (NK) cells. The capacity for acetylcholine synthesis by NK cells increased markedly under inflammatory conditions such as experimental autoimmune...



Synaptic properties of the lemniscal and paralemniscal pathways to the mouse somatosensory thalamus [Neuroscience]

2017-07-25T09:25:14-07:00

Somatosensory information is thought to arrive in thalamus through two glutamatergic routes called the lemniscal and paralemniscal pathways via the ventral posterior medial (VPm) and posterior medial (POm) nuclei. Here we challenge the view that these pathways functionally represent parallel information routes. Using electrical stimulation and an optogenetic approach in...



Corticogeniculate feedback sharpens the temporal precision and spatial resolution of visual signals in the ferret [Neuroscience]

2017-07-25T09:25:14-07:00

The corticogeniculate (CG) pathway connects the visual cortex with the visual thalamus (LGN) in the feedback direction and enables the cortex to directly influence its own input. Despite numerous investigations, the role of this feedback circuit in visual perception remained elusive. To probe the function of CG feedback in a...



Prediction of intracellular exposure bridges the gap between target- and cell-based drug discovery [Pharmacology]

2017-07-25T09:25:14-07:00

Inadequate target exposure is a major cause of high attrition in drug discovery. Here, we show that a label-free method for quantifying the intracellular bioavailability (Fic) of drug molecules predicts drug access to intracellular targets and hence, pharmacological effect. We determined Fic in multiple cellular assays and cell types representing...



Analyses of PDE-regulated phosphoproteomes reveal unique and specific cAMP-signaling modules in T cells [Pharmacology]

2017-07-25T09:25:14-07:00

Specific functions for different cyclic nucleotide phosphodiesterases (PDEs) have not yet been identified in most cell types. Conventional approaches to study PDE function typically rely on measurements of global cAMP, general increases in cAMP-dependent protein kinase (PKA), or the activity of exchange protein activated by cAMP (EPAC). Although newer approaches...



Loss of mouse cardiomyocyte talin-1 and talin-2 leads to {beta}-1 integrin reduction, costameric instability, and dilated cardiomyopathy [Physiology]

2017-07-25T09:25:14-07:00

Continuous contraction–relaxation cycles of the heart require strong and stable connections of cardiac myocytes (CMs) with the extracellular matrix (ECM) to preserve sarcolemmal integrity. CM attachment to the ECM is mediated by integrin complexes localized at the muscle adhesion sites termed costameres. The ubiquitously expressed cytoskeletal protein talin (Tln) is...



Caffeine induces gastric acid secretion via bitter taste signaling in gastric parietal cells [Physiology]

2017-07-25T09:25:14-07:00

Caffeine, generally known as a stimulant of gastric acid secretion (GAS), is a bitter-tasting compound that activates several taste type 2 bitter receptors (TAS2Rs). TAS2Rs are expressed in the mouth and in several extraoral sites, e.g., in the gastrointestinal tract, in which their functional role still needs to be clarified....



Why eyewitnesses fail [Psychological and Cognitive Sciences]

2017-07-25T09:25:13-07:00

Eyewitness identifications play an important role in the investigation and prosecution of crimes, but it is well known that eyewitnesses make mistakes, often with serious consequences. In light of these concerns, the National Academy of Sciences recently convened a panel of experts to undertake a comprehensive study of current practice...



Light-mediated self-organization of sunflower stands increases oil yield in the field [Agricultural Sciences]

2017-07-25T09:25:13-07:00

Here, we show a unique crop response to intraspecific interference, whereby neighboring sunflower plants in a row avoid each other by growing toward a more favorable light environment and collectively increase production per unit land area. In high-density stands, a given plant inclined toward one side of the interrow space,...



Cultural evolutionary theory: How culture evolves and why it matters [Colloquium Paper]

2017-07-25T09:25:13-07:00

Human cultural traits—behaviors, ideas, and technologies that can be learned from other individuals—can exhibit complex patterns of transmission and evolution, and researchers have developed theoretical models, both verbal and mathematical, to facilitate our understanding of these patterns. Many of the first quantitative models of cultural evolution were modified from existing...



Culture extends the scope of evolutionary biology in the great apes [Colloquium Paper]

2017-07-25T09:25:13-07:00

Discoveries about the cultures and cultural capacities of the great apes have played a leading role in the recognition emerging in recent decades that cultural inheritance can be a significant factor in the lives not only of humans but also of nonhuman animals. This prominence derives in part from these...



Evolutionary neuroscience of cumulative culture [Colloquium Paper]

2017-07-25T09:25:13-07:00

Culture suffuses all aspects of human life. It shapes our minds and bodies and has provided a cumulative inheritance of knowledge, skills, institutions, and artifacts that allows us to truly stand on the shoulders of giants. No other species approaches the extent, diversity, and complexity of human culture, but we...



News Feature: Can animal culture drive evolution? [Anthropology]

2017-07-25T09:25:12-07:00

Once the purview of humans, culture has been observed in all sorts of animals. But are these behaviors merely ephemeral fads or can they shape the genes and traits of future generations? In Antarctic waters, a group of killer whales makes a wave big enough to knock a seal from...



Older, sociable capuchins (Cebus capucinus) invent more social behaviors, but younger monkeys innovate more in other contexts [Colloquium Paper]

2017-07-25T09:25:13-07:00

An important extension to our understanding of evolutionary processes has been the discovery of the roles that individual and social learning play in creating recurring phenotypes on which selection can act. Cultural change occurs chiefly through invention of new behavioral variants combined with social transmission of the novel behaviors to...



Enhanced coupling of light into a turbid medium through microscopic interface engineering [Applied Biological Sciences]

2017-07-25T09:25:13-07:00

There are many optical detection and sensing methods used today that provide powerful ways to diagnose, characterize, and study materials. For example, the measurement of spontaneous Raman scattering allows for remote detection and identification of chemicals. Many other optical techniques provide unique solutions to learn about biological, chemical, and even...



UCP1 deficiency causes brown fat respiratory chain depletion and sensitizes mitochondria to calcium overload-induced dysfunction [Biochemistry]

2017-07-25T09:25:13-07:00

Brown adipose tissue (BAT) mitochondria exhibit high oxidative capacity and abundant expression of both electron transport chain components and uncoupling protein 1 (UCP1). UCP1 dissipates the mitochondrial proton motive force (Δp) generated by the respiratory chain and increases thermogenesis. Here we find that in mice genetically lacking UCP1, cold-induced activation...



Stable membrane orientations of small dual-topology membrane proteins [Biochemistry]

2017-07-25T09:25:13-07:00

The topologies of α-helical membrane proteins are generally thought to be determined during their cotranslational insertion into the membrane. It is typically assumed that membrane topologies remain static after this process has ended. Recent findings, however, question this static view by suggesting that some parts of, or even the whole...



MmpL3 is the flippase for mycolic acids in mycobacteria [Biochemistry]

2017-07-25T09:25:13-07:00

The defining feature of the mycobacterial outer membrane (OM) is the presence of mycolic acids (MAs), which, in part, render the bilayer extremely hydrophobic and impermeable to external insults, including many antibiotics. Although the biosynthetic pathway of MAs is well studied, the mechanism(s) by which these lipids are transported across...



mTORC1 activates SREBP-2 by suppressing cholesterol trafficking to lysosomes in mammalian cells [Biochemistry]

2017-07-25T09:25:13-07:00

mTORC1 is known to activate sterol regulatory element-binding proteins (SREBPs) including SREBP-2, a master regulator of cholesterol synthesis. Through incompletely understood mechanisms, activated mTORC1 triggers translocation of SREBP-2, an endoplasmic reticulum (ER) resident protein, to the Golgi where SREBP-2 is cleaved to translocate to the nucleus and activate gene expression...



Monomeric and fibrillar {alpha}-synuclein exert opposite effects on the catalytic cycle that promotes the proliferation of A{beta}42 aggregates [Biophysics and Computational Biology]

2017-07-25T09:25:13-07:00

The coaggregation of the amyloid-β peptide (Aβ) and α-synuclein is commonly observed in a range of neurodegenerative disorders, including Alzheimer’s and Parkinson’s diseases. The complex interplay between Aβ and α-synuclein has led to seemingly contradictory results on whether α-synuclein promotes or inhibits Aβ aggregation. Here, we show how these conflicts...



Crystal structure of CO-bound cytochrome c oxidase determined by serial femtosecond X-ray crystallography at room temperature [Biophysics and Computational Biology]

2017-07-25T09:25:13-07:00

Cytochrome c oxidase (CcO), the terminal enzyme in the electron transfer chain, translocates protons across the inner mitochondrial membrane by harnessing the free energy generated by the reduction of oxygen to water. Several redox-coupled proton translocation mechanisms have been proposed, but they lack confirmation, in part from the absence of...



Antibody-induced uncoating of human rhinovirus B14 [Biophysics and Computational Biology]

2017-07-25T09:25:13-07:00

Rhinoviruses (RVs) are the major causes of common colds in humans. They have a nonenveloped, icosahedral capsid surrounding a positive-strand RNA genome. Here we report that the antigen-binding (Fab) fragment of a neutralizing antibody (C5) can trigger genome release from RV-B14 to form emptied particles and neutralize virus infection. Using...



Otoferlin is a multivalent calcium-sensitive scaffold linking SNAREs and calcium channels [Biophysics and Computational Biology]

2017-07-25T09:25:13-07:00

Sensory hair cells rely on otoferlin as the calcium sensor for exocytosis and encoding of sound preferentially over the neuronal calcium sensor synaptotagmin. Although it is established that synaptotagmin cannot rescue the otoferlin KO phenotype, the large size and low solubility of otoferlin have prohibited direct biochemical comparisons that could...



Modeling adsorption properties of structurally deformed metal-organic frameworks using structure-property map [Chemistry]

2017-07-25T09:25:13-07:00

Structural deformation and collapse in metal-organic frameworks (MOFs) can lead to loss of long-range order, making it a challenge to model these amorphous materials using conventional computational methods. In this work, we show that a structure–property map consisting of simulated data for crystalline MOFs can be used to indirectly obtain...



Deletion of Gas2l3 in mice leads to specific defects in cardiomyocyte cytokinesis during development [Developmental Biology]

2017-07-25T09:25:13-07:00

GAS2L3 is a recently identified cytoskeleton-associated protein that interacts with actin filaments and tubulin. The in vivo function of GAS2L3 in mammals remains unknown. Here, we show that mice deficient in GAS2L3 die shortly after birth because of heart failure. Mammalian cardiomyocytes lose the ability to proliferate shortly after birth,...



Mercury evidence for pulsed volcanism during the end-Triassic mass extinction [Earth, Atmospheric, and Planetary Sciences]

2017-07-25T09:25:13-07:00

The Central Atlantic Magmatic Province (CAMP) has long been proposed as having a causal relationship with the end-Triassic extinction event (∼201.5 Ma). In North America and northern Africa, CAMP is preserved as multiple basaltic units interbedded with uppermost Triassic to lowermost Jurassic sediments. However, it has been unclear whether this...



Early Paleocene landbird supports rapid phylogenetic and morphological diversification of crown birds after the K-Pg mass extinction [Earth, Atmospheric, and Planetary Sciences]

2017-07-25T09:25:13-07:00

Evidence is accumulating for a rapid diversification of birds following the K–Pg extinction. Recent molecular divergence dating studies suggest that birds radiated explosively during the first few million years of the Paleocene; however, fossils from this interval remain poorly represented, hindering our understanding of morphological and ecological specialization in early...



Song hybridization events during revolutionary song change provide insights into cultural transmission in humpback whales [Colloquium Paper]

2017-07-25T09:25:13-07:00

Cultural processes occur in a wide variety of animal taxa, from insects to cetaceans. The songs of humpback whales are one of the most striking examples of the transmission of a cultural trait and social learning in any nonhuman animal. To understand how songs are learned, we investigate rare cases...



Identifying early modern human ecological niche expansions and associated cultural dynamics in the South African Middle Stone Age [Colloquium Paper]

2017-07-25T09:25:13-07:00

The archaeological record shows that typically human cultural traits emerged at different times, in different parts of the world, and among different hominin taxa. This pattern suggests that their emergence is the outcome of complex and nonlinear evolutionary trajectories, influenced by environmental, demographic, and social factors, that need to be...



Behavioral self-organization underlies the resilience of a coastal ecosystem [Ecology]

2017-07-25T09:25:13-07:00

Self-organized spatial patterns occur in many terrestrial, aquatic, and marine ecosystems. Theoretical models and observational studies suggest self-organization, the formation of patterns due to ecological interactions, is critical for enhanced ecosystem resilience. However, experimental tests of this cross-ecosystem theory are lacking. In this study, we experimentally test the hypothesis that...



Bayesian markets to elicit private information [Economic Sciences]

2017-07-25T09:25:13-07:00

Financial markets reveal what investors think about the future, and prediction markets are used to forecast election results. Could markets also encourage people to reveal private information, such as subjective judgments (e.g., “Are you satisfied with your life?”) or unverifiable facts? This paper shows how to design such markets, called...



On the debris-level origins of adhesive wear [Engineering]

2017-07-25T09:25:13-07:00

Every contacting surface inevitably experiences wear. Predicting the exact amount of material loss due to wear relies on empirical data and cannot be obtained from any physical model. Here, we analyze and quantify wear at the most fundamental level, i.e., wear debris particles. Our simulations show that the asperity junction...



Interannual cycles of Hantaan virus outbreaks at the human-animal interface in Central China are controlled by temperature and rainfall [Environmental Sciences]

2017-07-25T09:25:13-07:00

Hantavirus, a rodent-borne zoonotic pathogen, has a global distribution with 200,000 human infections diagnosed annually. In recent decades, repeated outbreaks of hantavirus infections have been reported in Eurasia and America. These outbreaks have led to public concern and an interest in understanding the underlying biological mechanisms. Here, we propose a...



The extension of biology through culture [Biological Sciences]

2017-07-25T09:25:13-07:00

Biology is the study of life. How our understanding of the nature and evolution of living systems is being enriched and extended through new discoveries about social learning and culture in human and nonhuman animals is the subject of the collection of articles we introduce here. Recent decades have revealed...



Gene-culture coevolution in whales and dolphins [Colloquium Paper]

2017-07-25T09:25:13-07:00

Whales and dolphins (Cetacea) have excellent social learning skills as well as a long and strong mother–calf bond. These features produce stable cultures, and, in some species, sympatric groups with different cultures. There is evidence and speculation that this cultural transmission of behavior has affected gene distributions. Culture seems to...



Cultural macroevolution matters [Colloquium Paper]

2017-07-25T09:25:13-07:00

Evolutionary thinking can be applied to both cultural microevolution and macroevolution. However, much of the current literature focuses on cultural microevolution. In this article, we argue that the growing availability of large cross-cultural datasets facilitates the use of computational methods derived from evolutionary biology to answer broad-scale questions about the...



Coevolution of cultural intelligence, extended life history, sociality, and brain size in primates [Colloquium Paper]

2017-07-25T09:25:13-07:00

Explanations for primate brain expansion and the evolution of human cognition and culture remain contentious despite extensive research. While multiple comparative analyses have investigated variation in brain size across primate species, very few have addressed why primates vary in how much they use social learning. Here, we evaluate the hypothesis...



Haploid selection within a single ejaculate increases offspring fitness [Evolution]

2017-07-25T09:25:13-07:00

An inescapable consequence of sex in eukaryotes is the evolution of a biphasic life cycle with alternating diploid and haploid phases. The occurrence of selection during the haploid phase can have far-reaching consequences for fundamental evolutionary processes including the rate of adaptation, the extent of inbreeding depression, and the load...



Fast and accurate HLA typing from short-read next-generation sequence data with xHLA [Genetics]

2017-07-25T09:25:13-07:00

The HLA gene complex on human chromosome 6 is one of the most polymorphic regions in the human genome and contributes in large part to the diversity of the immune system. Accurate typing of HLA genes with short-read sequencing data has historically been difficult due to the sequence similarity between...



BMTP-11 is active in preclinical models of human osteosarcoma and a candidate targeted drug for clinical translation [Medical Sciences]

2017-07-25T09:25:13-07:00

Osteosarcoma occurs predominantly in children and young adults. High-grade tumors require multidisciplinary treatment consisting of chemotherapy in the neoadjuvant and adjuvant settings, along with surgical intervention. Despite this approach, death from respiratory failure secondary to the development and progression of pulmonary metastases remains a significant problem. Here, we identify the...



tsRNA signatures in cancer [Medical Sciences]

2017-07-25T09:25:13-07:00

Small, noncoding RNAs are short untranslated RNA molecules, some of which have been associated with cancer development. Recently we showed that a class of small RNAs generated during the maturation process of tRNAs (tRNA-derived small RNAs, hereafter “tsRNAs”) is dysregulated in cancer. Specifically, we uncovered tsRNA signatures in chronic lymphocytic...



Polar delivery of Legionella type IV secretion system substrates is essential for virulence [Microbiology]

2017-07-25T09:25:13-07:00

A recurrent emerging theme is the targeting of proteins to subcellular microdomains within bacterial cells, particularly to the poles. In most cases, it has been assumed that this localization is critical to the protein’s function. Legionella pneumophila uses a type IVB secretion system (T4BSS) to export a large number of...



Auditory cortex interneuron development requires cadherins operating hair-cell mechanoelectrical transduction [Neuroscience]

2017-07-25T09:25:13-07:00

Many genetic forms of congenital deafness affect the sound reception antenna of cochlear sensory cells, the hair bundle. The resulting sensory deprivation jeopardizes auditory cortex (AC) maturation. Early prosthetic intervention should revive this process. Nevertheless, this view assumes that no intrinsic AC deficits coexist with the cochlear ones, a possibility...



Frequency-specific directed interactions in the human brain network for language [Neuroscience]

2017-07-25T09:25:13-07:00

The brain’s remarkable capacity for language requires bidirectional interactions between functionally specialized brain regions. We used magnetoencephalography to investigate interregional interactions in the brain network for language while 102 participants were reading sentences. Using Granger causality analysis, we identified inferior frontal cortex and anterior temporal regions to receive widespread input...



Acute inflammation regulates neuroregeneration through the NF-{kappa}B pathway in olfactory epithelium [Neuroscience]

2017-07-25T09:25:13-07:00

Adult neural stem cells/progenitor cells residing in the basal layer of the olfactory epithelium are capable of reconstituting the neuroepithelium even after severe damage. The molecular events underlying this regenerative capacity remain elusive. Here we show that the repair of neuroepithelium after lesioning is accompanied by an acute, but self-limited,...



Genetic identification of a hindbrain nucleus essential for innate vocalization [Neuroscience]

2017-07-25T09:25:13-07:00

Vocalization in young mice is an innate response to isolation or mechanical stimulation. Neuronal circuits that control vocalization and breathing overlap and rely on motor neurons that innervate laryngeal and expiratory muscles, but the brain center that coordinates these motor neurons has not been identified. Here, we show that the...



Entanglement and thermodynamics after a quantum quench in integrable systems [Physics]

2017-07-25T09:25:13-07:00

Entanglement and entropy are key concepts standing at the foundations of quantum and statistical mechanics. Recently, the study of quantum quenches revealed that these concepts are intricately intertwined. Although the unitary time evolution ensuing from a pure state maintains the system at zero entropy, local properties at long times are...



Probing large viscosities in glass-formers with nonequilibrium simulations [Physics]

2017-07-25T09:25:13-07:00

For decades, scientists have debated whether supercooled liquids stop flowing below a glass transition temperature Tg0 or whether motion continues to slow gradually down to zero temperature. Answering this question is challenging because human time scales set a limit on the largest measurable viscosity, and available data are equally well...



Genomic architecture of biomass heterosis in Arabidopsis [Plant Biology]

2017-07-25T09:25:13-07:00

Heterosis is most frequently manifested by the substantially increased vigorous growth of hybrids compared with their parents. Investigating genomic variations in natural populations is essential to understand the initial molecular mechanisms underlying heterosis in plants. Here, we characterized the genomic architecture associated with biomass heterosis in 200 Arabidopsis hybrids. The...



Structure of the Arabidopsis TOPLESS corepressor provides insight into the evolution of transcriptional repression [Plant Biology]

2017-07-25T09:25:13-07:00

Transcriptional repression involves a class of proteins called corepressors that link transcription factors to chromatin remodeling complexes. In plants such as Arabidopsis thaliana, the most prominent corepressor is TOPLESS (TPL), which plays a key role in hormone signaling and development. Here we present the crystallographic structure of the Arabidopsis TPL...



NLR network mediates immunity to diverse plant pathogens [Plant Biology]

2017-07-25T09:25:13-07:00

Both plants and animals rely on nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins to respond to invading pathogens and activate immune responses. An emerging concept of NLR function is that “sensor” NLR proteins are paired with “helper” NLRs to mediate immune signaling. However, our fundamental knowledge of sensor/helper NLRs in...



A social insect perspective on the evolution of social learning mechanisms [Colloquium Paper]

2017-07-25T09:25:13-07:00

The social world offers a wealth of opportunities to learn from others, and across the animal kingdom individuals capitalize on those opportunities. Here, we explore the role of natural selection in shaping the processes that underlie social information use, using a suite of experiments on social insects as case studies....



Pursuing Darwin’s curious parallel: Prospects for a science of cultural evolution [Colloquium Paper]

2017-07-25T09:25:13-07:00

In the past few decades, scholars from several disciplines have pursued the curious parallel noted by Darwin between the genetic evolution of species and the cultural evolution of beliefs, skills, knowledge, languages, institutions, and other forms of socially transmitted information. Here, I review current progress in the pursuit of an...



The evolution of cognitive mechanisms in response to cultural innovations [Colloquium Paper]

2017-07-25T09:25:13-07:00

When humans and other animals make cultural innovations, they also change their environment, thereby imposing new selective pressures that can modify their biological traits. For example, there is evidence that dairy farming by humans favored alleles for adult lactose tolerance. Similarly, the invention of cooking possibly affected the evolution of...



Synchronized practice helps bearded capuchin monkeys learn to extend attention while learning a tradition [Colloquium Paper]

2017-07-25T09:25:13-07:00

Culture extends biology in that the setting of development shapes the traditions that individuals learn, and over time, traditions evolve as occasional variations are learned by others. In humans, interactions with others impact the development of cognitive processes, such as sustained attention, that shape how individuals learn as well as...



Conformity does not perpetuate suboptimal traditions in a wild population of songbirds [Colloquium Paper]

2017-07-25T09:25:13-07:00

Social learning is important to the life history of many animals, helping individuals to acquire new adaptive behavior. However despite long-running debate, it remains an open question whether a reliance on social learning can also lead to mismatched or maladaptive behavior. In a previous study, we experimentally induced traditions for...



Intranasal oxytocin treatment for social deficits and biomarkers of response in children with autism [Psychological and Cognitive Sciences]

2017-07-25T09:25:13-07:00

Autism spectrum disorder (ASD) is characterized by core social deficits. Prognosis is poor, in part, because existing medications target only associated ASD features. Emerging evidence suggests that the neuropeptide oxytocin (OXT) may be a blood-based biomarker of social functioning and a possible treatment for ASD. However, prior OXT treatment trials...



Cumulative cultural learning: Development and diversity [Colloquium Paper]

2017-07-25T09:25:13-07:00

The complexity and variability of human culture is unmatched by any other species. Humans live in culturally constructed niches filled with artifacts, skills, beliefs, and practices that have been inherited, accumulated, and modified over generations. A causal account of the complexity of human culture must explain its distinguishing characteristics: It...



Young children communicate their ignorance and ask questions [Colloquium Paper]

2017-07-25T09:25:13-07:00

Children acquire information, especially about the culture in which they are being raised, by listening to other people. Recent evidence has shown that young children are selective learners who preferentially accept information, especially from informants who are likely to be representative of the surrounding culture. However, the extent to which...



Changes in cognitive flexibility and hypothesis search across human life history from childhood to adolescence to adulthood [Colloquium Paper]

2017-07-25T09:25:13-07:00

How was the evolution of our unique biological life history related to distinctive human developments in cognition and culture? We suggest that the extended human childhood and adolescence allows a balance between exploration and exploitation, between wider and narrower hypothesis search, and between innovation and imitation in cultural learning. In...



How language shapes the cultural inheritance of categories [Colloquium Paper]

2017-07-25T09:25:13-07:00

It is widely recognized that language plays a key role in the transmission of human culture, but relatively little is known about the mechanisms by which language simultaneously encourages both cultural stability and cultural innovation. This paper examines this issue by focusing on the use of language to transmit categories,...



Harm to self outweighs benefit to others in moral decision making [Psychological and Cognitive Sciences]

2017-07-25T09:25:13-07:00

How we make decisions that have direct consequences for ourselves and others forms the moral foundation of our society. Whereas economic theory contends that humans aim at maximizing their own gains, recent seminal psychological work suggests that our behavior is instead hyperaltruistic: We are more willing to sacrifice gains to...



Reduced orbitofrontal cortical volume is associated with interdependent self-construal [Psychological and Cognitive Sciences]

2017-07-25T09:25:13-07:00

Interdependent self-construal refers to a view of the self as embedded in relationships with others. Prior work suggests that this construal is linked to a strong value placed on social obligations and duties. Interdependent people are therefore cognitively attuned to others and various social events in their surroundings while down-regulating...



Correction for Li et al., Targeting reactive nitrogen species suppresses hereditary pancreatic cancer [Corrections]

2017-07-25T09:25:14-07:00

MEDICAL SCIENCES Correction for “Targeting reactive nitrogen species suppresses hereditary pancreatic cancer,” by Mo Li, Qian Chen, Teng Ma, and Xiaochun Yu, which was first published June 19, 2017; 10.1073/pnas.1702156114 (Proc Natl Acad Sci USA 114:7106–7111). The authors note that the author contributions footnote appeared incorrectly. Xiaochun Yu should be...



In This Issue [This Week in PNAS]

2017-07-18T09:05:06-07:00

Barley gene might hold a key to improving beer quality Altering redox conditions might improve beer quality. Image courtesy of iStockphoto/Givaga. Malting, which involves the enzymatic breakdown of proteins and starch found in barley grains during beer production, is known to be under genetic control, but few of the underlying...



Community land titles alone will not protect forests [Social Sciences]

2017-07-18T09:05:07-07:00

Blackman et al. (1) assess the forest cover impacts of providing indigenous Peruvian communities with formal title to land they have long inhabited. We applaud the authors’ use of high-quality forest change data and rigorous causal methods; both are critical gaps in the land tenure and forest change literature (2)....



Reply to Robinson et al.: Building the evidence base on the forest cover effects of community titling [Social Sciences]

2017-07-18T09:05:07-07:00

We thank Robinson et al. (1) for their thoughtful comments on our article (2). We agree with their main point, which is that our findings about the link between titling and forest cover change are context- and time-specific, and do not necessarily generalize to other countries and other periods. However,...



Structure of the C1 complex of complement [Biological Sciences]

2017-07-18T09:05:07-07:00

In PNAS, Mortensen et al. (1) propose a model of the C1 complex of complement derived from small-angle X-ray scattering (SAXS) and electron microscopy (EM) analyses that contradicts previously published models and suggests an intermolecular activation process. This proposal is largely derived from a conjectural structure of C1r2C1s2, the catalytic...



Reply to Arlaud et al.: Structure of the C1 complex and the unbound C1r2s2 tetramer [Biological Sciences]

2017-07-18T09:05:07-07:00

Arlaud et al. (1) raised concerns regarding our small-angle X-ray scattering (SAXS) and EM models of the unbound C1r2s2 tetramer (2). They reference studies supporting an interaction of two C1rs dimers via C1r CCP1–serine protease (SP) interactions. In response, we conducted refinements against our SAXS data by imposing distance restraints...



Mildred S. Dresselhaus (1930-2017): A fierce force of harmony [Retrospectives]

2017-07-18T09:05:06-07:00

Prof. Mildred S. Dresselhaus, fondly known as “Millie” and “Queen of Carbon Science,” passed away at age 86 on February 20, 2017. She was a pioneer in the research of carbon nanomaterials, a giant in experimental condensed matter physics, a fine musician, a compassionate mentor and role model to young...



Energetic redistribution in allostery to execute protein function [Biophysics and Computational Biology]

2017-07-18T09:05:06-07:00

A perturbation at one site of the protein could cause an effect at a distant site. This important biological phenomenon, termed the “allosteric effect,” is essential for protein regulation and cell signaling, playing an important role in cellular function. Its fundamental functional significance has inspired numerous works aiming to understand...



Quinolines block every step of malaria heme crystal growth [Chemistry]

2017-07-18T09:05:06-07:00

Malaria is a lethal zoonotic disease that has impacted human survival and indeed, the history of human civilizations worldwide. The first effective treatment for malaria was reported in 1632 with the use of quinine extracts from the bark of the cinchona tree. Since that time, quinoline compounds have been used...