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Preview: PNAS - RSS feed of Early Edition articles

PNAS - RSS feed of Early Edition articles



Proceedings of the National Academy of Sciences RSS feed -- Early Edition



 



Solar thermochemical splitting of water to generate hydrogen [Perspectives]

2017-05-18T11:58:25-07:00

Solar photochemical means of splitting water (artificial photosynthesis) to generate hydrogen is emerging as a viable process. The solar thermochemical route also promises to be an attractive means of achieving this objective. In this paper we present different types of thermochemical cycles that one can use for the purpose. These...



Water is an active matrix of life for cell and molecular biology [Perspectives]

2017-06-07T12:43:37-07:00

Szent-Győrgi called water the “matrix of life” and claimed that there was no life without it. This statement is true, as far as we know, on our planet, but it is not clear whether it must hold throughout the cosmos. To evaluate that question requires a close consideration of the...



Microscopic dynamics of charge separation at the aqueous electrochemical interface [Chemistry]

2017-07-11T09:36:45-07:00

We have used molecular simulation and methods of importance sampling to study the thermodynamics and kinetics of ionic charge separation at a liquid water–metal interface. We have considered this process using canonical examples of two different classes of ions: a simple alkali–halide pair, Na+I−, or classical ions, and the products...



Molecular characterization of water and surfactant AOT at nanoemulsion surfaces [Chemistry]

2017-07-31T11:51:02-07:00

Nanoemulsions and microemulsions are environments where oil and water can be solubilized in one another to provide a unique platform for many different biological and industrial applications. Nanoemulsions, unlike microemulsions, have seen little work done to characterize molecular interactions at their surfaces. This study provides a detailed investigation of the...



Mechanism of ion adsorption to aqueous interfaces: Graphene/water vs. air/water [Chemistry]

2017-08-21T12:06:10-07:00

The adsorption of ions to aqueous interfaces is a phenomenon that profoundly influences vital processes in many areas of science, including biology, atmospheric chemistry, electrical energy storage, and water process engineering. Although classical electrostatics theory predicts that ions are repelled from water/hydrophobe (e.g., air/water) interfaces, both computer simulations and experiments...



XFEL structures of the influenza M2 proton channel: Room temperature water networks and insights into proton conduction [Biophysics and Computational Biology]

2017-08-23T11:33:34-07:00

The M2 proton channel of influenza A is a drug target that is essential for the reproduction of the flu virus. It is also a model system for the study of selective, unidirectional proton transport across a membrane. Ordered water molecules arranged in “wires” inside the channel pore have been...



Self-healing catalysis in water [Chemistry]

2017-09-05T09:11:22-07:00

Principles for designing self-healing water-splitting catalysts are presented together with a formal kinetics model to account for the key chemical steps needed for self-healing. Self-healing may be realized if the catalysts are able to self-assemble at applied potentials less than that needed for catalyst turnover. Solution pH provides a convenient...



Specific cation effects at aqueous solution-vapor interfaces: Surfactant-like behavior of Li+ revealed by experiments and simulations [Chemistry]

2017-10-09T11:49:04-07:00

It is now well established by numerous experimental and computational studies that the adsorption propensities of inorganic anions conform to the Hofmeister series. The adsorption propensities of inorganic cations, such as the alkali metal cations, have received relatively little attention. Here we use a combination of liquid-jet X-ray photoelectron experiments...



Preprint servers facilitate scientific discourse [Editorials]

2017-10-19T12:39:37-07:00

Preprints are scientific manuscripts posted online before formal peer-review and publication in journals. Preprints have become prominent in scientific publishing, which is increasingly shaped by an emphasis on speed, transparency, and accessibility. Important as they are, those factors are entwined with the journal’s primary role as an arbiter of the...



Efficient gene knockin in axolotl and its use to test the role of satellite cells in limb regeneration [Developmental Biology]

2017-10-31T08:46:38-07:00

Salamanders exhibit extensive regenerative capacities and serve as a unique model in regeneration research. However, due to the lack of targeted gene knockin approaches, it has been difficult to label and manipulate some of the cell populations that are crucial for understanding the mechanisms underlying regeneration. Here we have established...



Intercellular competition and the inevitability of multicellular aging [Evolution]

2017-10-30T11:44:48-07:00

Current theories attribute aging to a failure of selection, due to either pleiotropic constraints or declining strength of selection after the onset of reproduction. These theories implicitly leave open the possibility that if senescence-causing alleles could be identified, or if antagonistic pleiotropy could be broken, the effects of aging might...



Coexpression of NOS2 and COX2 accelerates tumor growth and reduces survival in estrogen receptor-negative breast cancer [Pharmacology]

2017-10-27T13:29:00-07:00

Proinflammatory signaling pathways are commonly up-regulated in breast cancer. In estrogen receptor-negative (ER−) and triple-negative breast cancer (TNBC), nitric oxide synthase-2 (NOS2) and cyclooxygenase-2 (COX2) have been described as independent predictors of disease outcome. We further explore these findings by investigating the impact of their coexpression on breast cancer survival....



Quantifying the limits of transition state theory in enzymatic catalysis [Biophysics and Computational Biology]

2017-11-03T12:34:27-07:00

While being one of the most popular reaction rate theories, the applicability of transition state theory to the study of enzymatic reactions has been often challenged. The complex dynamic nature of the protein environment raised the question about the validity of the nonrecrossing hypothesis, a cornerstone in this theory. We...



Scale-dependent climatic drivers of human epidemics in ancient China [Ecology]

2017-11-06T12:06:52-08:00

A wide range of climate change-induced effects have been implicated in the prevalence of infectious diseases. Disentangling causes and consequences, however, remains particularly challenging at historical time scales, for which the quality and quantity of most of the available natural proxy archives and written documentary sources often decline. Here, we...



Hominid butchers and biting crocodiles in the African Plio-Pleistocene [Anthropology]

2017-11-06T12:06:53-08:00

Zooarchaeologists have long relied on linear traces and pits found on the surfaces of ancient bones to infer ancient hominid behaviors such as slicing, chopping, and percussive actions during butchery of mammal carcasses. However, such claims about Plio–Pleistocene hominids rely mostly on very small assemblages of bony remains. Furthermore, recent...



Molecular basis of tactile specialization in the duck bill [Physiology]

2017-11-06T12:06:53-08:00

Tactile-foraging ducks are specialist birds known for their touch-dependent feeding behavior. They use dabbling, straining, and filtering to find edible matter in murky water, relying on the sense of touch in their bill. Here, we present the molecular characterization of embryonic duck bill, which we show contains a high density...



Metabolic control of regulatory T cell (Treg) survival and function by Lkb1 [Immunology and Inflammation]

2017-11-06T12:06:53-08:00

The metabolic programs of functionally distinct T cell subsets are tailored to their immunologic activities. While quiescent T cells use oxidative phosphorylation (OXPHOS) for energy production, and effector T cells (Teffs) rely on glycolysis for proliferation, the distinct metabolic features of regulatory T cells (Tregs) are less well established. Here...



Poaceae-specific MS1 encodes a phospholipid-binding protein for male fertility in bread wheat [Plant Biology]

2017-11-06T12:06:54-08:00

Male sterility is an essential trait in hybrid seed production for monoclinous crops, including rice and wheat. However, compared with the high percentage of hybrid rice planted in the world, little commercial hybrid wheat is planted globally as a result of the lack of a suitable system for male sterility....



A transient dopamine signal encodes subjective value and causally influences demand in an economic context [Neuroscience]

2017-11-06T12:06:54-08:00

The mesolimbic dopamine system is strongly implicated in motivational processes. Currently accepted theories suggest that transient mesolimbic dopamine release events energize reward seeking and encode reward value. During the pursuit of reward, critical associations are formed between the reward and cues that predict its availability. Conditioned by these experiences, dopamine...



Ribonucleotides incorporated by the yeast mitochondrial DNA polymerase are not repaired [Biochemistry]

2017-11-06T12:06:55-08:00

Incorporation of ribonucleotides into DNA during genome replication is a significant source of genomic instability. The frequency of ribonucleotides in DNA is determined by deoxyribonucleoside triphosphate/ribonucleoside triphosphate (dNTP/rNTP) ratios, by the ability of DNA polymerases to discriminate against ribonucleotides, and by the capacity of repair mechanisms to remove incorporated ribonucleotides....



Natural language indicators of differential gene regulation in the human immune system [Medical Sciences]

2017-11-06T12:06:55-08:00

Adverse social conditions have been linked to a conserved transcriptional response to adversity (CTRA) in circulating leukocytes that may contribute to social gradients in disease. However, the CNS mechanisms involved remain obscure, in part because CTRA gene-expression profiles often track external social–environmental variables more closely than they do self-reported internal...



Scale-dependent portfolio effects explain growth inflation and volatility reduction in landscape demography [Ecology]

2017-11-06T12:06:56-08:00

Population demography is central to fundamental ecology and for predicting range shifts, decline of threatened species, and spread of invasive organisms. There is a mismatch between most demographic work, carried out on few populations and at local scales, and the need to predict dynamics at landscape and regional scales. Inspired...



Myoanatomy of the velvet worm leg revealed by laboratory-based nanofocus X-ray source tomography [Evolution]

2017-11-06T12:06:56-08:00

X-ray computed tomography (CT) is a powerful noninvasive technique for investigating the inner structure of objects and organisms. However, the resolution of laboratory CT systems is typically limited to the micrometer range. In this paper, we present a table-top nanoCT system in conjunction with standard processing tools that is able...



Epoxide metabolites of arachidonate and docosahexaenoate function conversely in acute kidney inȷury involved in GSK3{beta} signaling [Pharmacology]

2017-11-06T12:06:56-08:00

Acute kidney injury (AKI) causes severe morbidity and mortality for which new therapeutic strategies are needed. Docosahexaenoic acid (DHA), arachidonic acid (ARA), and their metabolites have various effects in kidney injury, but their molecular mechanisms are largely unknown. Here, we report that 14 (15)-epoxyeicosatrienoic acid [14 (15)-EET] and 19 (20)-epoxydocosapentaenoic...



Diminished Ost3-dependent N-glycosylation of the BiP nucleotide exchange factor Sil1 is an adaptive response to reductive ER stress [Cell Biology]

2017-11-06T12:06:56-08:00

BiP (Kar2 in yeast) is an essential Hsp70 chaperone and master regulator of endoplasmic reticulum (ER) function. BiP’s activity is regulated by its intrinsic ATPase activity that can be stimulated by two different nucleotide exchange factors, Sil1 and Lhs1. Both Sil1 and Lhs1 are glycoproteins, but how N-glycosylation regulates their...



Protein engineering of the chemokine CCL20 prevents psoriasiform dermatitis in an IL-23-dependent murine model [Biochemistry]

2017-11-06T12:06:57-08:00

Psoriasis is a chronic inflammatory skin disease characterized by the infiltration of T cell and other immune cells to the skin in response to injury or autoantigens. Conventional, as well as unconventional, γδ T cells are recruited to the dermis and epidermis by CCL20 and other chemokines. Together with its...



Syntenin mediates SRC function in exosomal cell-to-cell communication [Cell Biology]

2017-11-06T12:06:57-08:00

The cytoplasmic tyrosine kinase SRC controls cell growth, proliferation, adhesion, and motility. The current view is that SRC acts primarily downstream of cell-surface receptors to control intracellular signaling cascades. Here we reveal that SRC functions in cell-to-cell communication by controlling the biogenesis and the activity of exosomes. Exosomes are viral-like...



Structure and mechanotransmission mechanism of the MacB ABC transporter superfamily [Microbiology]

2017-11-06T12:06:58-08:00

MacB is an ABC transporter that collaborates with the MacA adaptor protein and TolC exit duct to drive efflux of antibiotics and enterotoxin STII out of the bacterial cell. Here we present the structure of ATP-bound MacB and reveal precise molecular details of its mechanism. The MacB transmembrane domain lacks...



Blockade of activin type II receptors with a dual anti-ActRIIA/IIB antibody is critical to promote maximal skeletal muscle hypertrophy [Applied Biological Sciences]

2017-11-06T12:06:58-08:00

The TGF-β family ligands myostatin, GDF11, and activins are negative regulators of skeletal muscle mass, which have been reported to primarily signal via the ActRIIB receptor on skeletal muscle and thereby induce muscle wasting described as cachexia. Use of a soluble ActRIIB-Fc “trap,” to block myostatin pathway signaling in normal...



Near-infrared remotely triggered drug-release strategies for cancer treatment [Engineering]

2017-11-06T12:06:59-08:00

Remotely controlled, localized drug delivery is highly desirable for potentially minimizing the systemic toxicity induced by the administration of typically hydrophobic chemotherapy drugs by conventional means. Nanoparticle-based drug delivery systems provide a highly promising approach for localized drug delivery, and are an emerging field of interest in cancer treatment. Here,...



Engineering of a membrane-triggered activity switch in coagulation factor VIIa [Biochemistry]

2017-11-06T12:06:59-08:00

Recombinant factor VIIa (FVIIa) variants with increased activity offer the promise to improve the treatment of bleeding episodes in patients with inhibitor-complicated hemophilia. Here, an approach was adopted to enhance the activity of FVIIa by selectively optimizing substrate turnover at the membrane surface. Under physiological conditions, endogenous FVIIa engages its...



Gut microbiomes and reproductive isolation in Drosophila [Evolution]

2017-11-06T12:06:59-08:00

Experimental studies of the evolution of reproductive isolation (RI) in real time are a powerful way in which to reveal fundamental, early processes that initiate divergence. In a classic speciation experiment, populations of Drosophila pseudoobscura were subjected to divergent dietary selection and evolved significant positive assortative mating by diet. More...



Coordinated regulation of heterochromatin inheritance by Dpb3-Dpb4 complex [Genetics]

2017-11-06T12:06:59-08:00

During DNA replication, chromatin is disrupted ahead of the replication fork, and epigenetic information must be restored behind the fork. How epigenetic marks are inherited through DNA replication remains poorly understood. Histone H3 lysine 9 (H3K9) methylation and histone hypoacetylation are conserved hallmarks of heterochromatin. We previously showed that the...



Ultrafast 25-fs relaxation in highly excited states of methyl azide mediated by strong nonadiabatic coupling [Chemistry]

2017-11-06T12:07:00-08:00

Highly excited electronic states are challenging to explore experimentally and theoretically—due to the large density of states and the fact that small structural changes lead to large changes in electronic character with associated strong nonadiabatic dynamics. They can play a key role in astrophysical and ionospheric chemistry, as well as...



Oxalate-curcumin-based probe for micro- and macroimaging of reactive oxygen species in Alzheimer’s disease [Applied Biological Sciences]

2017-11-06T12:07:00-08:00

Alzheimer’s disease (AD) is an irreversible neurodegenerative disorder that has a progression that is closely associated with oxidative stress. It has long been speculated that the reactive oxygen species (ROS) level in AD brains is much higher than that in healthy brains. However, evidence from living beings is scarce. Inspired...



Enzyme stabilization via computationally guided protein stapling [Chemistry]

2017-11-06T12:07:01-08:00

Thermostabilization represents a critical and often obligatory step toward enhancing the robustness of enzymes for organic synthesis and other applications. While directed evolution methods have provided valuable tools for this purpose, these protocols are laborious and time-consuming and typically require the accumulation of several mutations, potentially at the expense of...



Limiting (zero-load) speed of the rotary motor of Escherichia coli is independent of the number of torque-generating units [Biophysics and Computational Biology]

2017-11-06T12:07:01-08:00

Rotation of the bacterial flagellar motor is driven by multiple torque-generating units (stator elements). The torque-generating dynamics can be understood in terms of the “duty ratio” of the stator elements, that is, the fraction of time a stator element engages with the rotor during its mechanochemical cycle. The dependence of...



Circadian clock cryptochrome proteins regulate autoimmunity [Immunology and Inflammation]

2017-11-06T12:07:01-08:00

The circadian system regulates numerous physiological processes including immune responses. Here, we show that mice deficient of the circadian clock genes Cry1 and Cry2 [Cry double knockout (DKO)] develop an autoimmune phenotype including high serum IgG concentrations, serum antinuclear antibodies, and precipitation of IgG, IgM, and complement 3 in glomeruli...



Charged residues in the H-NS linker drive DNA binding and gene silencing in single cells [Biophysics and Computational Biology]

2017-11-06T12:07:02-08:00

Nucleoid-associated proteins (NAPs) facilitate chromosome organization in bacteria, but the precise mechanism remains elusive. H-NS is a NAP that also plays a major role in silencing pathogen genes. We used genetics, single-particle tracking in live cells, superresolution microscopy, atomic force microscopy, and molecular dynamics simulations to examine H-NS/DNA interactions in...



Host-based lipid inflammation drives pathogenesis in Francisella infection [Microbiology]

2017-11-06T12:07:03-08:00

Mass spectrometry imaging (MSI) was used to elucidate host lipids involved in the inflammatory signaling pathway generated at the host–pathogen interface during a septic bacterial infection. Using Francisella novicida as a model organism, a bacterial lipid virulence factor (endotoxin) was imaged and identified along with host phospholipids involved in the...



Observation of a remarkable reduction of correlation effects in BaCr2As2 by ARPES [Physics]

2017-11-06T12:07:04-08:00

The superconducting phase in iron-based high-Tc superconductors (FeSC), as in other unconventional superconductors such as the cuprates, neighbors a magnetically ordered one in the phase diagram. This proximity hints at the importance of electron correlation effects in these materials, and Hund’s exchange interaction has been suggested to be the dominant...



Selective deuteration illuminates the importance of tunneling in the unimolecular decay of Criegee intermediates to hydroxyl radical products [Chemistry]

2017-11-06T12:07:04-08:00

Ozonolysis of alkenes, an important nonphotolytic source of hydroxyl (OH) radicals in the atmosphere, proceeds through unimolecular decay of Criegee intermediates. Here, we report a large kinetic isotope effect associated with the rate-limiting hydrogen-transfer step that releases OH radicals for a prototypical Criegee intermediate, CH3CHOO. IR excitation of selectively deuterated...



Ion pair particles at the air-water interface [Earth, Atmospheric, and Planetary Sciences]

2017-11-06T12:07:05-08:00

Although the role of methanesulfonic acid (HMSA) in particle formation in the gas phase has been extensively studied, the details of the HMSA-induced ion pair particle formation at the air–water interface are yet to be examined. In this work, we have performed Born–Oppenheimer molecular dynamics simulations and density functional theory...



Key amino acid residues conferring enhanced enzyme activity at cold temperatures in an Antarctic polyextremophilic {beta}-galactosidase [Genetics]

2017-11-06T12:07:05-08:00

The Antarctic microorganism Halorubrum lacusprofundi harbors a model polyextremophilic β-galactosidase that functions in cold, hypersaline conditions. Six amino acid residues potentially important for cold activity were identified by comparative genomics and substituted with evolutionarily conserved residues (N251D, A263S, I299L, F387L, I476V, and V482L) in closely related homologs from mesophilic haloarchaea....



Effect of paleoseawater composition on hydrothermal exchange in midocean ridges [Earth, Atmospheric, and Planetary Sciences]

2017-11-06T12:07:05-08:00

Variations in the Mg, Ca, Sr, and SO4 concentrations of paleoseawater can affect the chemical exchange between seawater and oceanic basalt in hydrothermal systems at midocean ridges (MOR). We present a model for evaluating the nature and magnitude of these previously unappreciated effects, using available estimates of paleoseawater composition over...



Subplate neurons are the first cortical neurons to respond to sensory stimuli [Neuroscience]

2017-11-07T08:17:36-08:00

In utero experience, such as maternal speech in humans, can shape later perception, although the underlying cortical substrate is unknown. In adult mammals, ascending thalamocortical projections target layer 4, and the onset of sensory responses in the cortex is thought to be dependent on the onset of thalamocortical transmission to...



Pulsed evolution shaped modern vertebrate body sizes [Evolution]

2017-11-07T08:17:37-08:00

The relative importance of different modes of evolution in shaping phenotypic diversity remains a hotly debated question. Fossil data suggest that stasis may be a common mode of evolution, while modern data suggest some lineages experience very fast rates of evolution. One way to reconcile these observations is to imagine...



High-temperature charge density wave correlations in La1.875Ba0.125CuO4 without spin-charge locking [Physics]

2017-11-07T08:17:37-08:00

Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and spin, with a locked periodicity, others host charge density waves (CDWs) without any obviously related spin order. Here we...



DNA damage response protein TOPBP1 regulates X chromosome silencing in the mammalian germ line [Genetics]

2017-11-07T08:17:38-08:00

Meiotic synapsis and recombination between homologs permits the formation of cross-overs that are essential for generating chromosomally balanced sperm and eggs. In mammals, surveillance mechanisms eliminate meiotic cells with defective synapsis, thereby minimizing transmission of aneuploidy. One such surveillance mechanism is meiotic silencing, the inactivation of genes located on asynapsed...



Three-dimensional visualization and a deep-learning model reveal complex fungal parasite networks in behaviorally manipulated ants [Microbiology]

2017-11-07T08:17:38-08:00

Some microbes possess the ability to adaptively manipulate host behavior. To better understand how such microbial parasites control animal behavior, we examine the cell-level interactions between the species-specific fungal parasite Ophiocordyceps unilateralis sensu lato and its carpenter ant host (Camponotus castaneus) at a crucial moment in the parasite’s lifecycle: when...



Incremental heating of Bishop Tuff sanidine reveals preeruptive radiogenic Ar and rapid remobilization from cold storage [Earth, Atmospheric, and Planetary Sciences]

2017-11-07T08:17:39-08:00

Accurate and precise ages of large silicic eruptions are critical to calibrating the geologic timescale and gauging the tempo of changes in climate, biologic evolution, and magmatic processes throughout Earth history. The conventional approach to dating these eruptive products using the 40Ar/39Ar method is to fuse dozens of individual feldspar...



Directed evolution of SecB chaperones toward toxin-antitoxin systems [Microbiology]

2017-11-07T08:17:39-08:00

SecB chaperones assist protein export in bacteria. However, certain SecB family members have diverged to become specialized toward the control of toxin-antitoxin (TA) systems known to promote bacterial adaptation to stress and persistence. In such tripartite TA-chaperone (TAC) systems, the chaperone was shown to assist folding and to prevent degradation...



Effect of naturally occurring Wolbachia in Anopheles gambiae s.l. mosquitoes from Mali on Plasmodium falciparum malaria transmission [Microbiology]

2017-11-07T08:17:40-08:00

A naturally occurring Wolbachia strain (wAnga-Mali) was identified in mosquitoes of the Anopheles gambiae complex collected in the Malian villages of Dangassa and Kenieroba. Phylogenetic analysis of the nucleotide sequence of two 16S rRNA regions showed that wAnga-Mali clusters with Wolbachia strains from supergroup A and has the highest homology...



How social information can improve estimation accuracy in human groups [Applied Physical Sciences]

2017-11-08T12:08:43-08:00

In our digital and connected societies, the development of social networks, online shopping, and reputation systems raises the questions of how individuals use social information and how it affects their decisions. We report experiments performed in France and Japan, in which subjects could update their estimates after having received information...



Structural basis for arginine methylation-independent recognition of PIWIL1 by TDRD2 [Biophysics and Computational Biology]

2017-11-08T12:08:43-08:00

The P-element–induced wimpy testis (PIWI)-interacting RNA (piRNA) pathway plays a central role in transposon silencing and genome protection in the animal germline. A family of Tudor domain proteins regulates the piRNA pathway through direct Tudor domain–PIWI interactions. Tudor domains are known to fulfill this function by binding to methylated PIWI...



In vivo measurements of interindividual differences in DNA glycosylases and APE1 activities [Cell Biology]

2017-11-09T11:39:18-08:00

The integrity of our DNA is challenged with at least 100,000 lesions per cell on a daily basis. Failure to repair DNA damage efficiently can lead to cancer, immunodeficiency, and neurodegenerative disease. Base excision repair (BER) recognizes and repairs minimally helix-distorting DNA base lesions induced by both endogenous and exogenous...



Reply to Kalinkat et al.: Smallest terrestrial vertebrates are highly imperiled [Letters (Online Only)]

2017-11-09T13:20:03-08:00

Kalinkat et al. (1) discuss the biodiversity crisis in their reply to our article “Extinction risk is most acute for the world’s largest and smallest vertebrates” (2). We agree with Kalinkat et al. (1) that small freshwater species tend to have elevated extinction risk, an issue that we highlight in...



Exceptional body size-extinction risk relations shed new light on the freshwater biodiversity crisis [Letters (Online Only)]

2017-11-09T14:12:10-08:00

In PNAS, Ripple et al. (1) show that the smallest species of reptiles, amphibians, and bony fishes suffer unusually high extinction risks given what we know about general body size–extinction risk relationships (2). The results of this study have important implications, considering that most studies exploring the community- or ecosystem-level...



Adding landscape genetics and individual traits to the ecosystem function paradigm reveals the importance of species functional breadth [Ecology]

2017-11-10T11:43:59-08:00

Animal pollination mediates both reproduction and gene flow for the majority of plant species across the globe. However, past functional studies have focused largely on seed production; although useful, this focus on seed set does not provide information regarding species-specific contributions to pollen-mediated gene flow. Here we quantify pollen dispersal...



Insights into functions of the H channel of cytochrome c oxidase from atomistic molecular dynamics simulations [Biophysics and Computational Biology]

2017-11-13T11:40:58-08:00

Proton pumping A-type cytochrome c oxidase (CcO) terminates the respiratory chains of mitochondria and many bacteria. Three possible proton transfer pathways (D, K, and H channels) have been identified based on structural, functional, and mutational data. Whereas the D channel provides the route for all pumped protons in bacterial A-type...



Assessing the present and future probability of Hurricane Harvey’s rainfall [Earth, Atmospheric, and Planetary Sciences]

2017-11-13T11:40:58-08:00

We estimate, for current and future climates, the annual probability of areally averaged hurricane rain of Hurricane Harvey’s magnitude by downscaling large numbers of tropical cyclones from three climate reanalyses and six climate models. For the state of Texas, we estimate that the annual probability of 500 mm of area-integrated...



Selective killing of Helicobacter pylori with pH-responsive helix-coil conformation transitionable antimicrobial polypeptides [Chemistry]

2017-11-13T11:40:58-08:00

Current clinical treatment of Helicobacter pylori infection, the main etiological factor in the development of gastritis, gastric ulcers, and gastric carcinoma, requires a combination of at least two antibiotics and one proton pump inhibitor. However, such triple therapy suffers from progressively decreased therapeutic efficacy due to the drug resistance and...



Recovery of taste organs and sensory function after severe loss from Hedgehog/Smoothened inhibition with cancer drug sonidegib [Cell Biology]

2017-11-13T11:40:58-08:00

Striking taste disturbances are reported in cancer patients treated with Hedgehog (HH)-pathway inhibitor drugs, including sonidegib (LDE225), which block the HH pathway effector Smoothened (SMO). We tested the potential for molecular, cellular, and functional recovery in mice from the severe disruption of taste-organ biology and taste sensation that follows HH/SMO...



Adaptive benefits from small mutation supplies in an antibiotic resistance enzyme [Evolution]

2017-11-13T11:40:58-08:00

Populations with large mutation supplies adapt via the “greedy” substitution of the fittest genotype available, leading to fast and repeatable short-term responses. At longer time scales, smaller mutation supplies may in theory lead to larger improvements when distant high-fitness genotypes more readily evolve from lower-fitness intermediates. Here we test for...



Closed-loop control of targeted ultrasound drug delivery across the blood-brain/tumor barriers in a rat glioma model [Engineering]

2017-11-13T11:40:59-08:00

Cavitation-facilitated microbubble-mediated focused ultrasound therapy is a promising method of drug delivery across the blood–brain barrier (BBB) for treating many neurological disorders. Unlike ultrasound thermal therapies, during which magnetic resonance thermometry can serve as a reliable treatment control modality, real-time control of modulated BBB disruption with undetectable vascular damage remains...



Sequential induction of Fur-regulated genes in response to iron limitation in Bacillus subtilis [Genetics]

2017-11-13T11:40:59-08:00

Bacterial cells modulate transcription in response to changes in iron availability. The ferric uptake regulator (Fur) senses intracellular iron availability and plays a central role in maintaining iron homeostasis in Bacillus subtilis. Here we utilized FrvA, a high-affinity Fe2+ efflux transporter from Listeria monocytogenes, as an inducible genetic tool to...



Role of estrogen receptor beta in neural differentiation of mouse embryonic stem cells [Medical Sciences]

2017-11-13T11:40:59-08:00

The ability to propagate mature cells and tissue from pluripotent stem cells offers enormous promise for treating many diseases, including neurodegenerative diseases. Before such cells can be used successfully in neurodegenerative diseases without causing unwanted cell growth and migration, genes regulating growth and migration of neural stem cells need to...



RNA stem structure governs coupling of dicing and gene silencing in RNA interference [Biophysics and Computational Biology]

2017-11-13T11:40:59-08:00

PremicroRNAs (premiRNAs) possess secondary structures consisting of a loop and a stem with multiple mismatches. Despite the well-characterized RNAi pathway, how the structural features of premiRNA contribute to dicing and subsequent gene-silencing efficiency remains unclear. Using single-molecule FISH, we demonstrate that cytoplasmic mRNA, but not nuclear mRNA, is reduced during...



Repression of miR-31 by BCL6 stabilizes the helper function of human follicular helper T cells [Immunology and Inflammation]

2017-11-13T11:41:00-08:00

Follicular helper T cells (TFHs) are a key component of adaptive immune responses as they help antibody production by B cells. Differentiation and function of TFH cells are controlled by the master gene BCL6, but it is largely unclear how this transcription repressor specifies the TFH program. Here we asked...



Skill networks and measures of complex human capital [Social Sciences]

2017-11-13T11:41:00-08:00

We propose a network-based method for measuring worker skills. We illustrate the method using data from an online freelance website. Using the tools of network analysis, we divide skills into endogenous categories based on their relationship with other skills in the market. Workers who specialize in these different areas earn...



Analysis of high-resolution 3D intrachromosomal interactions aided by Bayesian network modeling [Biophysics and Computational Biology]

2017-11-13T11:41:00-08:00

Long-range intrachromosomal interactions play an important role in 3D chromosome structure and function, but our understanding of how various factors contribute to the strength of these interactions remains poor. In this study we used a recently developed analysis framework for Bayesian network (BN) modeling to analyze publicly available datasets for...



Multiple Legionella pneumophila effector virulence phenotypes revealed through high-throughput analysis of targeted mutant libraries [Microbiology]

2017-11-13T11:40:52-08:00

Legionella pneumophila is the causative agent of a severe pneumonia called Legionnaires’ disease. A single strain of L. pneumophila encodes a repertoire of over 300 different effector proteins that are delivered into host cells by the Dot/Icm type IV secretion system during infection. The large number of L. pneumophila effectors...



Assigning chemoreceptors to chemosensory pathways in Pseudomonas aeruginosa [Microbiology]

2017-11-13T11:40:52-08:00

In contrast to Escherichia coli, a model organism for chemotaxis that has 5 chemoreceptors and a single chemosensory pathway, Pseudomonas aeruginosa PAO1 has a much more complex chemosensory network, which consists of 26 chemoreceptors feeding into four chemosensory pathways. While several chemoreceptors were rigorously linked to specific pathways in a...



Parochial trust and cooperation across 17 societies [Psychological and Cognitive Sciences]

2017-11-13T11:40:52-08:00

International challenges such as climate change, poverty, and intergroup conflict require countries to cooperate to solve these complex problems. However, the political tide in many countries has shifted inward, with skepticism and reluctance to cooperate with other countries. Thus, cross-societal investigations are needed to test theory about trust and cooperation...



Parallel magnetic field suppresses dissipation in superconducting nanostrips [Applied Physical Sciences]

2017-11-13T11:40:52-08:00

The motion of Abrikosov vortices in type-II superconductors results in a finite resistance in the presence of an applied electric current. Elimination or reduction of the resistance via immobilization of vortices is the “holy grail” of superconductivity research. Common wisdom dictates that an increase in the magnetic field escalates the...



Proteome-wide modulation of degradation dynamics in response to growth arrest [Biochemistry]

2017-11-13T11:40:52-08:00

In dividing cells, cytoplasmic dilution is the dominant route of clearance for long-lived proteins whose inherent degradation is slower than the cellular growth rate. Thus, as cells transition from a dividing to a nondividing state, there is a propensity for long-lived proteins to become stabilized relative to short-lived proteins, leading...



Ecosystem management and land conservation can substantially contribute to California’s climate mitigation goals [Sustainability Science]

2017-11-13T11:40:53-08:00

Modeling efforts focused on future greenhouse gas (GHG) emissions from energy and other sectors in California have shown varying capacities to meet the emissions reduction targets established by the state. These efforts have not included potential reductions from changes in ecosystem management, restoration, and conservation. We examine the scale of...



Psychological targeting as an effective approach to digital mass persuasion [Social Sciences]

2017-11-13T11:40:53-08:00

People are exposed to persuasive communication across many different contexts: Governments, companies, and political parties use persuasive appeals to encourage people to eat healthier, purchase a particular product, or vote for a specific candidate. Laboratory studies show that such persuasive appeals are more effective in influencing behavior when they are...



Unprecedented pathway of reducing equivalents in a diflavin-linked disulfide oxidoreductase [Biochemistry]

2017-11-13T11:40:53-08:00

Flavoproteins participate in a wide variety of physiologically relevant processes that typically involve redox reactions. Within this protein superfamily, there exists a group that is able to transfer reducing equivalents from FAD to a redox-active disulfide bridge, which further reduces disulfide bridges in target proteins to regulate their structure and...



Specific inhibition of GPCR-independent G protein signaling by a rationally engineered protein [Biochemistry]

2017-11-13T11:40:53-08:00

Activation of heterotrimeric G proteins by cytoplasmic nonreceptor proteins is an alternative to the classical mechanism via G protein-coupled receptors (GPCRs). A subset of nonreceptor G protein activators is characterized by a conserved sequence named the Gα-binding and activating (GBA) motif, which confers guanine nucleotide exchange factor (GEF) activity in...



Cell-autonomous adiposity through increased cell surface GLUT4 due to ankyrin-B deficiency [Cell Biology]

2017-11-13T11:40:53-08:00

Obesity typically is linked to caloric imbalance as a result of overnutrition. Here we propose a cell-autonomous mechanism for adiposity as a result of persistent cell surface glucose transporter type 4 (GLUT4) in adipocytes resulting from impaired function of ankyrin-B (AnkB) in coupling GLUT4 to clathrin-mediated endocytosis. Adipose tissue-specific AnkB-KO...



Socioeconomic status and genetic influences on cognitive development [Psychological and Cognitive Sciences]

2017-11-13T11:40:54-08:00

Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status (SES) families, including recent proposals that the pattern is a...



Correlating kinetic and structural data on ubiquinone binding and reduction by respiratory complex I [Biochemistry]

2017-11-13T11:40:54-08:00

Respiratory complex I (NADH:ubiquinone oxidoreductase), one of the largest membrane-bound enzymes in mammalian cells, powers ATP synthesis by using the energy from electron transfer from NADH to ubiquinone-10 to drive protons across the energy-transducing mitochondrial inner membrane. Ubiquinone-10 is extremely hydrophobic, but in complex I the binding site for its...



Phenological shifts conserve thermal niches in North American birds and reshape expectations for climate-driven range shifts [Ecology]

2017-11-13T11:40:54-08:00

Species respond to climate change in two dominant ways: range shifts in latitude or elevation and phenological shifts of life-history events. Range shifts are widely viewed as the principal mechanism for thermal niche tracking, and phenological shifts in birds and other consumers are widely understood as the principal mechanism for...



RSK2 phosphorylates T-bet to attenuate colon cancer metastasis and growth [Immunology and Inflammation]

2017-11-13T11:40:54-08:00

Metastasis is a major cause of cancer-related deaths. Approximately 80% of patients with colorectal cancer develop liver metastasis and 20% develop lung metastasis. We found that at different stages of colon cancer, IFNγ secretion from peripheral blood mononuclear cells was decreased compared with healthy controls. The ribosomal S6 kinase (RSK)...



Human resistin protects against endotoxic shock by blocking LPS-TLR4 interaction [Immunology and Inflammation]

2017-11-13T11:40:55-08:00

Helminths trigger multiple immunomodulatory pathways that can protect from sepsis. Human resistin (hRetn) is an immune cell-derived protein that is highly elevated in helminth infection and sepsis. However, the function of hRetn in sepsis, or whether hRetn influences helminth protection against sepsis, is unknown. Employing hRetn-expressing transgenic mice (hRETNTg+) and...



Normalized value coding explains dynamic adaptation in the human valuation process [Neuroscience]

2017-11-13T11:40:55-08:00

The notion of subjective value is central to choice theories in ecology, economics, and psychology, serving as an integrated decision variable by which options are compared. Subjective value is often assumed to be an absolute quantity, determined in a static manner by the properties of an individual option. Recent neurobiological...



Supercooled and glassy water: Metastable liquid(s), amorphous solid(s), and a no-man’s land [Perspectives]

2017-11-13T11:40:55-08:00

We review the recent research on supercooled and glassy water, focusing on the possible origins of its complex behavior. We stress the central role played by the strong directionality of the water–water interaction and by the competition between local energy, local entropy, and local density. In this context we discuss...



Resident macrophages of pancreatic islets have a seminal role in the initiation of autoimmune diabetes of NOD mice [Immunology and Inflammation]

2017-11-13T11:40:55-08:00

Treatment of C57BL/6 or NOD mice with a monoclonal antibody to the CSF-1 receptor resulted in depletion of the resident macrophages of pancreatic islets of Langerhans that lasted for several weeks. Depletion of macrophages in C57BL/6 mice did not affect multiple parameters of islet function, including glucose response, insulin content,...



Early Neolithic wine of Georgia in the South Caucasus [Anthropology]

2017-11-13T11:40:56-08:00

Chemical analyses of ancient organic compounds absorbed into the pottery fabrics from sites in Georgia in the South Caucasus region, dating to the early Neolithic period (ca. 6,000–5,000 BC), provide the earliest biomolecular archaeological evidence for grape wine and viniculture from the Near East, at ca. 6,000–5,800 BC. The chemical...



Gap junctional coupling between retinal amacrine and ganglion cells underlies coherent activity integral to global object perception [Neuroscience]

2017-11-13T11:40:56-08:00

Coherent spike activity occurs between widely separated retinal ganglion cells (RGCs) in response to a large, contiguous object, but not to disjointed objects. Since the large spatial separation between the RGCs precludes common excitatory inputs from bipolar cells, the mechanism underlying this long-range coherence remains unclear. Here, we show that...



Dopamine reward prediction error signal codes the temporal evaluation of a perceptual decision report [Neuroscience]

2017-11-13T11:40:56-08:00

Learning to associate unambiguous sensory cues with rewarded choices is known to be mediated by dopamine (DA) neurons. However, little is known about how these neurons behave when choices rely on uncertain reward-predicting stimuli. To study this issue we reanalyzed DA recordings from monkeys engaged in the detection of weak...



Matter wave speckle observed in an out-of-equilibrium quantum fluid [Physics]

2017-11-13T11:40:56-08:00

We report the results of the direct comparison of a freely expanding turbulent Bose–Einstein condensate and a propagating optical speckle pattern. We found remarkably similar statistical properties underlying the spatial propagation of both phenomena. The calculated second-order correlation together with the typical correlation length of each system is used to...



Mechanism of SOA formation determines magnitude of radiative effects [Earth, Atmospheric, and Planetary Sciences]

2017-11-13T11:40:57-08:00

Secondary organic aerosol (SOA) nearly always exists as an internal mixture, and the distribution of this mixture depends on the formation mechanism of SOA. A model is developed to examine the influence of using an internal mixing state based on the mechanism of formation and to estimate the radiative forcing...



Phasic inhibition as a mechanism for generation of rapid respiratory rhythms [Neuroscience]

2017-11-13T11:40:57-08:00

Central neural networks operate continuously throughout life to control respiration, yet mechanisms regulating ventilatory frequency are poorly understood. Inspiration is generated by the pre-Bötzinger complex of the ventrolateral medulla, where it is thought that excitation increases inspiratory frequency and inhibition causes apnea. To test this model, we used an in...



Intact hemisphere and corpus callosum compensate for visuomotor functions after early visual cortex damage [Neuroscience]

2017-11-13T11:40:57-08:00

Unilateral damage to the primary visual cortex (V1) leads to clinical blindness in the opposite visual hemifield, yet nonconscious ability to transform unseen visual input into motor output can be retained, a condition known as “blindsight.” Here we combined psychophysics, functional magnetic resonance imaging, and tractography to investigate the functional...



Microbial pathway for anaerobic 5'-methylthioadenosine metabolism coupled to ethylene formation [Microbiology]

2017-11-13T11:40:57-08:00

Numerous cellular processes involving S-adenosyl-l-methionine result in the formation of the toxic by-product, 5′-methylthioadenosine (MTA). To prevent inhibitory MTA accumulation and retain biologically available sulfur, most organisms possess the “universal” methionine salvage pathway (MSP). However, the universal MSP is inherently aerobic due to a requirement of molecular oxygen for one...



Correction for Danhart et al., Conformational and chemical selection by a trans-acting editing domain [Corrections]

2017-11-13T11:40:52-08:00

BIOCHEMISTRY Correction for “Conformational and chemical selection by a trans-acting editing domain,” by Eric M. Danhart, Marina Bakhtina, William A. Cantara, Alexandra B. Kuzmishin, Xiao Ma, Brianne L. Sanford, Marija Košutić, Yuki Goto, Hiroaki Suga, Kotaro Nakanishi, Ronald Micura, Mark P. Foster, and Karin Musier-Forsyth, which was first published August...



Sparsity enables estimation of both subcortical and cortical activity from MEG and EEG [Neuroscience]

2017-11-14T08:42:05-08:00

Subcortical structures play a critical role in brain function. However, options for assessing electrophysiological activity in these structures are limited. Electromagnetic fields generated by neuronal activity in subcortical structures can be recorded noninvasively, using magnetoencephalography (MEG) and electroencephalography (EEG). However, these subcortical signals are much weaker than those generated by...



Intrusion and extrusion of water in hydrophobic nanopores [Applied Physical Sciences]

2017-11-14T08:42:06-08:00

Heterogeneous systems composed of hydrophobic nanoporous materials and water are capable, depending on their characteristics, of efficiently dissipating (dampers) or storing (“molecular springs”) energy. However, it is difficult to predict their properties based on macroscopic theories—classical capillarity for intrusion and classical nucleation theory (CNT) for extrusion—because of the peculiar behavior...