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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...



Allocating dissipation across a molecular machine cycle to maximize flux [Biophysics and Computational Biology]

2017-10-03T08:32:56-07:00

Biomolecular machines consume free energy to break symmetry and make directed progress. Nonequilibrium ATP concentrations are the typical free energy source, with one cycle of a molecular machine consuming a certain number of ATP, providing a fixed free energy budget. Since evolution is expected to favor rapid-turnover machines that operate...



Minimal and RNA-free RNase P in Aquifex aeolicus [Biochemistry]

2017-10-03T08:32:56-07:00

RNase P is an essential tRNA-processing enzyme in all domains of life. We identified an unknown type of protein-only RNase P in the hyperthermophilic bacterium Aquifex aeolicus: Without an RNA subunit and the smallest of its kind, the 23-kDa polypeptide comprises a metallonuclease domain only. The protein has RNase P...



Tectonic conformational changes of a coronavirus spike glycoprotein promote membrane fusion [Biophysics and Computational Biology]

2017-10-03T08:32:56-07:00

The tremendous pandemic potential of coronaviruses was demonstrated twice in the past few decades by two global outbreaks of deadly pneumonia. The coronavirus spike (S) glycoprotein initiates infection by promoting fusion of the viral and cellular membranes through conformational changes that remain largely uncharacterized. Here we report the cryoEM structure...



Direct measurement of weakly nonequilibrium system entropy is consistent with Gibbs-Shannon form [Physics]

2017-10-03T08:32:56-07:00

Stochastic thermodynamics extends classical thermodynamics to small systems in contact with one or more heat baths. It can account for the effects of thermal fluctuations and describe systems far from thermodynamic equilibrium. A basic assumption is that the expression for Shannon entropy is the appropriate description for the entropy of...



Mechanically switching single-molecule fluorescence of GFP by unfolding and refolding [Biophysics and Computational Biology]

2017-10-03T08:32:57-07:00

Green fluorescent protein (GFP) variants are widely used as genetically encoded fluorescent fusion tags, and there is an increasing interest in engineering their structure to develop in vivo optical sensors, such as for optogenetics and force transduction. Ensemble experiments have shown that the fluorescence of GFP is quenched upon denaturation....



Multigenerational silencing dynamics control cell aging [Systems Biology]

2017-10-03T08:32:57-07:00

Cellular aging plays an important role in many diseases, such as cancers, metabolic syndromes, and neurodegenerative disorders. There has been steady progress in identifying aging-related factors such as reactive oxygen species and genomic instability, yet an emerging challenge is to reconcile the contributions of these factors with the fact that...



Methyl-compound use and slow growth characterize microbial life in 2-km-deep subseafloor coal and shale beds [Environmental Sciences]

2017-10-03T08:32:57-07:00

The past decade of scientific ocean drilling has revealed seemingly ubiquitous, slow-growing microbial life within a range of deep biosphere habitats. Integrated Ocean Drilling Program Expedition 337 expanded these studies by successfully coring Miocene-aged coal beds 2 km below the seafloor hypothesized to be “hot spots” for microbial life. To...



Spontaneous self-dislodging of freezing water droplets and the role of wettability [Applied Physical Sciences]

2017-09-25T11:48:56-07:00

Spontaneous removal of liquid, solidifying liquid and solid forms of matter from surfaces, is of significant importance in nature and technology, where it finds applications ranging from self-cleaning to icephobicity and to condensation systems. However, it is a great challenge to understand fundamentally the complex interaction of rapidly solidifying, typically...



On the origin of biological construction, with a focus on multicellularity [Perspectives]

2017-09-29T11:54:49-07:00

Biology is marked by a hierarchical organization: all life consists of cells; in some cases, these cells assemble into groups, such as endosymbionts or multicellular organisms; in turn, multicellular organisms sometimes assemble into yet other groups, such as primate societies or ant colonies. The construction of new organizational layers results...



Universal poroelastic mechanism for hydraulic signals in biomimetic and natural branches [Plant Biology]

2017-10-02T12:05:44-07:00

Plants constantly undergo external mechanical loads such as wind or touch and respond to these stimuli by acclimating their growth processes. A fascinating feature of this mechanical-induced growth response is that it can occur rapidly and at long distance from the initial site of stimulation, suggesting the existence of a...



Structural basis underlying complex assembly and conformational transition of the type I R-M system [Biophysics and Computational Biology]

2017-10-02T12:05:44-07:00

Type I restriction-modification (R-M) systems are multisubunit enzymes with separate DNA-recognition (S), methylation (M), and restriction (R) subunits. Despite extensive studies spanning five decades, the detailed molecular mechanisms underlying subunit assembly and conformational transition are still unclear due to the lack of high-resolution structural information. Here, we report the atomic...



Cannabidiol attenuates seizures and social deficits in a mouse model of Dravet syndrome [Neuroscience]

2017-10-02T12:05:45-07:00

Worldwide medicinal use of cannabis is rapidly escalating, despite limited evidence of its efficacy from preclinical and clinical studies. Here we show that cannabidiol (CBD) effectively reduced seizures and autistic-like social deficits in a well-validated mouse genetic model of Dravet syndrome (DS), a severe childhood epilepsy disorder caused by loss-of-function...



Root-associated fungal microbiota of nonmycorrhizal Arabis alpina and its contribution to plant phosphorus nutrition [Plant Biology]

2017-10-02T12:05:45-07:00

Most land plants live in association with arbuscular mycorrhizal (AM) fungi and rely on this symbiosis to scavenge phosphorus (P) from soil. The ability to establish this partnership has been lost in some plant lineages like the Brassicaceae, which raises the question of what alternative nutrition strategies such plants have...



Early snowmelt significantly enhances boreal springtime carbon uptake [Earth, Atmospheric, and Planetary Sciences]

2017-10-02T12:05:46-07:00

We determine the annual timing of spring recovery from space-borne microwave radiometer observations across northern hemisphere boreal evergreen forests for 1979–2014. We find a trend of advanced spring recovery of carbon uptake for this period, with a total average shift of 8.1 d (2.3 d/decade). We use this trend to...



Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan [Environmental Sciences]

2017-10-02T12:05:46-07:00

There are 440 operational nuclear reactors in the world, with approximately one-half situated along the coastline. This includes the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which experienced multiple reactor meltdowns in March 2011 followed by the release of radioactivity to the marine environment. While surface inputs to the ocean via...



Prairie strips improve biodiversity and the delivery of multiple ecosystem services from corn-soybean croplands [Sustainability Science]

2017-10-02T12:05:47-07:00

Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland....



Short- and long-term effects of imprisonment on future felony convictions and prison admissions [Social Sciences]

2017-10-02T12:05:47-07:00

A substantial contributor to prison admissions is the return of individuals recently released from prison, which has come to be known as prison’s “revolving door.” However, it is unclear whether being sentenced to prison itself has a causal effect on the probability of a subsequent return to prison or on...



Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest [Ecology]

2017-10-02T12:05:47-07:00

The Janzen–Connell (JC) hypothesis provides a conceptual framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet—that recruits experience high mortality near conspecifics and at high densities—assumes a degree of host specialization in interactions between plants and natural enemies. Studies confirming JC effects have focused primarily...



Mycobacterium tuberculosis inhibits human innate immune responses via the production of TLR2 antagonist glycolipids [Immunology and Inflammation]

2017-10-02T12:05:48-07:00

Mycobacterium tuberculosis is a major human pathogen that is able to survive inside host cells and resist immune clearance. Most particularly, it inhibits several arms of the innate immune response, including phagosome maturation or cytokine production. To better understand the molecular mechanisms by which M. tuberculosis circumvents host immune defenses,...



Li-rich antiperovskite superionic conductors based on cluster ions [Applied Physical Sciences]

2017-10-02T12:05:48-07:00

Enjoying great safety, high power, and high energy densities, all-solid-state batteries play a key role in the next generation energy storage devices. However, their development is limited by the lack of solid electrolyte materials that can reach the practically useful conductivities of 10−2 S/cm at room temperature (RT). Here, by...



Discovery of an O-mannosylation pathway selectively serving cadherins and protocadherins [Cell Biology]

2017-10-02T12:05:48-07:00

The cadherin (cdh) superfamily of adhesion molecules carry O-linked mannose (O-Man) glycans at highly conserved sites localized to specific β-strands of their extracellular cdh (EC) domains. These O-Man glycans do not appear to be elongated like O-Man glycans found on α-dystroglycan (α-DG), and we recently demonstrated that initiation of cdh/protocadherin...



Projections of white and black older adults without living kin in the United States, 2015 to 2060 [Social Sciences]

2017-10-02T12:05:49-07:00

Close kin provide many important functions as adults age, affecting health, financial well-being, and happiness. Those without kin report higher rates of loneliness and experience elevated risks of chronic illness and nursing facility placement. Historical racial differences and recent shifts in core demographic rates suggest that white and black older...



Detection of isolated protein-bound metal ions by single-particle cryo-STEM [Biophysics and Computational Biology]

2017-10-02T12:05:49-07:00

Metal ions play essential roles in many aspects of biological chemistry. Detecting their presence and location in proteins and cells is important for understanding biological function. Conventional structural methods such as X-ray crystallography and cryo-transmission electron microscopy can identify metal atoms on protein only if the protein structure is solved...



Interhost dispersal alters microbiome assembly and can overwhelm host innate immunity in an experimental zebrafish model [Ecology]

2017-10-02T12:05:49-07:00

The diverse collections of microorganisms associated with humans and other animals, collectively referred to as their “microbiome,” are critical for host health, but the mechanisms that govern their assembly are poorly understood. This has made it difficult to identify consistent host factors that explain variation in microbiomes across hosts, despite...



Elliptical orbits of microspheres in an evanescent field [Engineering]

2017-10-02T12:05:50-07:00

We examine the motion of periodically driven and optically tweezed microspheres in fluid and find a rich variety of dynamic regimes. We demonstrate, in experiment and in theory, that mean particle motion in 2D is rarely parallel to the direction of the applied force and can even exhibit elliptical orbits...



Granulocyte-colony-stimulating factor (G-CSF) signaling in spinal microglia drives visceral sensitization following colitis [Neuroscience]

2017-10-02T12:05:50-07:00

Pain is a main symptom of inflammatory diseases and often persists beyond clinical remission. Although we have a good understanding of the mechanisms of sensitization at the periphery during inflammation, little is known about the mediators that drive central sensitization. Recent reports have identified hematopoietic colony-stimulating factors as important regulators...



High-intensity urban light installation dramatically alters nocturnal bird migration [Ecology]

2017-10-02T12:05:50-07:00

Billions of nocturnally migrating birds move through increasingly photopolluted skies, relying on cues for navigation and orientation that artificial light at night (ALAN) can impair. However, no studies have quantified avian responses to powerful ground-based light sources in urban areas. We studied effects of ALAN on migrating birds by monitoring...



Rapid evolution of hosts begets species diversity at the cost of intraspecific diversity [Evolution]

2017-10-02T12:05:50-07:00

Ecosystems are complex food webs in which multiple species interact and ecological and evolutionary processes continuously shape populations and communities. Previous studies on eco-evolutionary dynamics have shown that the presence of intraspecific diversity affects community structure and function, and that eco-evolutionary feedback dynamics can be an important driver for its...



Asynchronous warming and {delta}18O evolution of deep Atlantic water masses during the last deglaciation [Earth, Atmospheric, and Planetary Sciences]

2017-10-02T12:05:50-07:00

The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties...



An anion-immobilized composite electrolyte for dendrite-free lithium metal anodes [Chemistry]

2017-10-02T12:05:51-07:00

Lithium metal is strongly regarded as a promising electrode material in next-generation rechargeable batteries due to its extremely high theoretical specific capacity and lowest reduction potential. However, the safety issue and short lifespan induced by uncontrolled dendrite growth have hindered the practical applications of lithium metal anodes. Hence, we propose...



Host-derived fatty acids activate type VII secretion in Staphylococcus aureus [Microbiology]

2017-10-02T12:05:51-07:00

The type VII secretion system (T7SS) of Staphylococcus aureus is a multiprotein complex dedicated to the export of several virulence factors during host infection. This virulence pathway plays a key role in promoting bacterial survival and the long-term persistence of staphylococcal abscess communities. The expression of the T7SS is activated...



Semisynthetic glycoconjugate vaccine candidate against Streptococcus pneumoniae serotype 5 [Medical Sciences]

2017-10-02T12:05:51-07:00

Glycoconjugate vaccines based on isolated capsular polysaccharide (CPS) save millions of lives annually by preventing invasive pneumococcal disease caused by Streptococcus pneumoniae. Some components of the S. pneumoniae glycoconjugate vaccine Prevnar13 that contains CPS antigens from 13 serotypes undergo modifications or degradation during isolation and conjugation, resulting in production problems...



Molecular mechanisms and structural features of cardiomyopathy-causing troponin T mutants in the tropomyosin overlap region [Biochemistry]

2017-10-02T12:05:51-07:00

Point mutations in genes encoding sarcomeric proteins are the leading cause of inherited primary cardiomyopathies. Among them are mutations in the TNNT2 gene that encodes cardiac troponin T (TnT). These mutations are clustered in the tropomyosin (Tm) binding region of TnT, TNT1 (residues 80–180). To understand the mechanistic changes caused...



Extracellular vesicles from human pancreatic islets suppress human islet amyloid polypeptide amyloid formation [Biochemistry]

2017-10-02T12:05:52-07:00

Extracellular vesicles (EVs) are small vesicles released by cells to aid cell–cell communication and tissue homeostasis. Human islet amyloid polypeptide (IAPP) is the major component of amyloid deposits found in pancreatic islets of patients with type 2 diabetes (T2D). IAPP is secreted in conjunction with insulin from pancreatic β cells...



Phenotypic variation explains food web structural patterns [Ecology]

2017-10-02T12:05:52-07:00

Food webs (i.e., networks of species and their feeding interactions) share multiple structural features across ecosystems. The factors explaining such similarities are still debated, and the role played by most organismal traits and their intraspecific variation is unknown. Here, we assess how variation in traits controlling predator–prey interactions (e.g., body...



Chemical substitutions in the selectivity filter of potassium channels do not rule out constricted-like conformations for C-type inactivation [Biophysics and Computational Biology]

2017-10-02T12:05:52-07:00

In many K+ channels, prolonged activating stimuli lead to a time-dependent reduction in ion conduction, a phenomenon known as C-type inactivation. X-ray structures of the KcsA channel suggest that this inactivated state corresponds to a “constricted” conformation of the selectivity filter. However, the functional significance of the constricted conformation has...



Stress attenuates the flexible updating of aversive value [Psychological and Cognitive Sciences]

2017-10-02T12:05:52-07:00

In a dynamic environment, sources of threat or safety can unexpectedly change, requiring the flexible updating of stimulus−outcome associations that promote adaptive behavior. However, aversive contexts in which we are required to update predictions of threat are often marked by stress. Acute stress is thought to reduce behavioral flexibility, yet...



Structure and dynamics of the RNAPII CTDsome with Rtt103 [Biochemistry]

2017-10-04T11:47:00-07:00

RNA polymerase II contains a long C-terminal domain (CTD) that regulates interactions at the site of transcription. The CTD architecture remains poorly understood due to its low sequence complexity, dynamic phosphorylation patterns, and structural variability. We used integrative structural biology to visualize the architecture of the CTD in complex with...



Divergence of developmental trajectories is triggered interactively by early social and ecological experience in a cooperative breeder [Evolution]

2017-10-06T12:08:58-07:00

Cooperative breeders feature the highest level of social complexity among vertebrates. Environmental constraints foster the evolution of this form of social organization, selecting for both well-developed social and ecological competences. Cooperative breeders pursue one of two alternative social trajectories: delaying reproduction to care for the offspring of dominant breeders or...



Correction to Supporting Information for Palermo et al., CRISPR-Cas9 conformational activation as elucidated from enhanced molecular simulations [SI Correction]

2017-10-09T11:49:05-07:00

BIOPHYSICS AND COMPUTATIONAL BIOLOGY, BIOCHEMISTRY Correction to Supporting Information for “CRISPR-Cas9 conformational activation as elucidated from enhanced molecular simulations,” by Giulia Palermo, Yinglong Miao, Ross C. Walker, Martin Jinek, and J. Andrew McCammon, which was first published June 26, 2017; 10.1073/pnas.1707645114 (Proc Natl Acad Sci USA 114:7260–7265). The authors note...



Correction for Dixon et al., Combined hydrogels that switch human pluripotent stem cells from self-renewal to differentiation [Corrections]

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

CELL BIOLOGY Correction for “Combined hydrogels that switch human pluripotent stem cells from self-renewal to differentiation,” by James E. Dixon, Disheet A. Shah, Catherine Rogers, Stephen Hall, Nicola Weston, Christopher D. J. Parmenter, Donal McNally, Chris Denning, and Kevin M. Shakesheff, which was first published March 27, 2014; 10.1073/pnas.1319685111 (Proc...



Content of mitochondrial calcium uniporter (MCU) in cardiomyocytes is regulated by microRNA-1 in physiologic and pathologic hypertrophy [Cell Biology]

2017-10-09T11:49:02-07:00

The mitochondrial Ca2+ uniporter complex (MCUC) is a multimeric ion channel which, by tuning Ca2+ influx into the mitochondrial matrix, finely regulates metabolic energy production. In the heart, this dynamic control of mitochondrial Ca2+ uptake is fundamental for cardiomyocytes to adapt to either physiologic or pathologic stresses. Mitochondrial calcium uniporter...



Modulation of apoptotic response by LAR family phosphatases-cIAP1 signaling during urinary tract morphogenesis [Developmental Biology]

2017-10-09T11:49:02-07:00

The elimination of unwanted cells by apoptosis is necessary for tissue morphogenesis. However, the cellular control of morphogenetic apoptosis is poorly understood, notably the modulation of cell sensitivity to apoptotic stimuli. Ureter maturation, the process by which the ureter is displaced to the bladder wall, represents an exquisite example of...



Big data modeling to predict platelet usage and minimize wastage in a tertiary care system [Medical Sciences]

2017-10-09T11:49:02-07:00

Maintaining a robust blood product supply is an essential requirement to guarantee optimal patient care in modern health care systems. However, daily blood product use is difficult to anticipate. Platelet products are the most variable in daily usage, have short shelf lives, and are also the most expensive to produce,...



Macrophage-like nanoparticles concurrently absorbing endotoxins and proinflammatory cytokines for sepsis management [Engineering]

2017-10-09T11:49:03-07:00

Sepsis, resulting from uncontrolled inflammatory responses to bacterial infections, continues to cause high morbidity and mortality worldwide. Currently, effective sepsis treatments are lacking in the clinic, and care remains primarily supportive. Here we report the development of macrophage biomimetic nanoparticles for the management of sepsis. The nanoparticles, made by wrapping...



PrimPol is required for replication reinitiation after mtDNA damage [Biochemistry]

2017-10-09T11:49:03-07:00

Eukaryotic PrimPol is a recently discovered DNA-dependent DNA primase and translesion synthesis DNA polymerase found in the nucleus and mitochondria. Although PrimPol has been shown to be required for repriming of stalled replication forks in the nucleus, its role in mitochondria has remained unresolved. Here we demonstrate in vivo and...



Dominant negative effect of the loss-of-function {gamma}-secretase mutants on the wild-type enzyme through heterooligomerization [Biochemistry]

2017-10-09T11:49:03-07:00

γ-secretase is an intramembrane protease complex consisting of nicastrin, presenilin-1/2, APH-1a/b, and Pen-2. Hydrolysis of the 99-residue transmembrane fragment of amyloid precursor protein (APP-C99) by γ-secretase produces β-amyloid (Aβ) peptides. Pathogenic mutations in PSEN1 and PSEN2, which encode the catalytic subunit presenilin-1/2 of γ-secretase, lead to familial Alzheimer’s disease in...



Staufen1 inhibits MyoD translation to actively maintain muscle stem cell quiescence [Cell Biology]

2017-10-09T11:49:03-07:00

Tissue regeneration depends on the timely activation of adult stem cells. In skeletal muscle, the adult stem cells maintain a quiescent state and proliferate upon injury. We show that muscle stem cells (MuSCs) use direct translational repression to maintain the quiescent state. High-resolution single-molecule and single-cell analyses demonstrate that quiescent...



Kinship and familiarity mitigate costs of social conflict between Seychelles warbler neighbors [Evolution]

2017-10-09T11:49:03-07:00

Because virtually all organisms compete with others in their social environment, mechanisms that reduce conflict between interacting individuals are crucial for the evolution of stable families, groups, and societies. Here, we tested whether costs of social conflict over territorial space between Seychelles warblers (Acrocephalus sechellensis) are mitigated by kin-selected (genetic...



Engineering sulfur storage in maize seed proteins without apparent yield loss [Agricultural Sciences]

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

Sulfur assimilation may limit the pool of methionine and cysteine available for incorporation into zeins, the major seed storage proteins in maize. This hypothesis was tested by producing transgenic maize with deregulated sulfate reduction capacity achieved through leaf-specific expression of the Escherichia coli enzyme 3′-phosphoadenosine-5′-phosphosulfate reductase (EcPAPR) that resulted in...



TREM2 deficiency attenuates neuroinflammation and protects against neurodegeneration in a mouse model of tauopathy [Neuroscience]

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

Variants in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) were recently found to increase the risk for developing Alzheimer’s disease (AD). In the brain, TREM2 is predominately expressed on microglia, and its association with AD adds to increasing evidence implicating a role for the innate...



Formation of most of our coal brought Earth close to global glaciation [Earth, Atmospheric, and Planetary Sciences]

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

The bulk of Earth’s coal deposits used as fossil fuel today was formed from plant debris during the late Carboniferous and early Permian periods. The high burial rate of organic carbon correlates with a significant drawdown of atmospheric carbon dioxide (CO2) at that time. A recent analysis of a high-resolution...



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...



Small-molecule inhibitors directly target CARD9 and mimic its protective variant in inflammatory bowel disease [Biochemistry]

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

Advances in human genetics have dramatically expanded our understanding of complex heritable diseases. Genome-wide association studies have identified an allelic series of CARD9 variants associated with increased risk of or protection from inflammatory bowel disease (IBD). The predisposing variant of CARD9 is associated with increased NF-κB–mediated cytokine production. Conversely, the...



PAF promotes stemness and radioresistance of glioma stem cells [Medical Sciences]

2017-10-09T11:49:05-07:00

An integrated genomic and functional analysis to elucidate DNA damage signaling factors promoting self-renewal of glioma stem cells (GSCs) identified proliferating cell nuclear antigen (PCNA)-associated factor (PAF) up-regulation in glioblastoma. PAF is preferentially overexpressed in GSCs. Its depletion impairs maintenance of self-renewal without promoting differentiation and reduces tumor-initiating cell frequency....



Semiconductor quantum dot-sensitized rainbow photocathode for effective photoelectrochemical hydrogen generation [Chemistry]

2017-10-09T11:49:05-07:00

The present study reports the fabrication of CdSe quantum dot (QD)-sensitized photocathodes on NiO-coated indium tin oxide (ITO) electrodes and their H2-generating ability upon light irradiation. A well-established spin-coating method was used to deposit CdSe QD stock solution onto the surface of NiO/ITO electrodes, thereby leading to the construction of...



Phylogenetic diversity anomaly in angiosperms between eastern Asia and eastern North America [Ecology]

2017-10-09T11:49:05-07:00

Although eastern Asia (EAS) and eastern North America (ENA) have similar climates, plant species richness in EAS greatly exceeds that in ENA. The degree to which this diversity difference reflects the ages of the floras or their rates of evolutionary diversification has not been quantified. Measures of species diversity that...



Bird specimens track 135 years of atmospheric black carbon and environmental policy [Environmental Sciences]

2017-10-09T11:49:05-07:00

Atmospheric black carbon has long been recognized as a public health and environmental concern. More recently, black carbon has been identified as a major, ongoing contributor to anthropogenic climate change, thus making historical emission inventories of black carbon an essential tool for assessing past climate sensitivity and modeling future climate...



Geophysical potential for wind energy over the open oceans [Sustainability Science]

2017-10-09T11:49:06-07:00

Wind turbines continuously remove kinetic energy from the lower troposphere, thereby reducing the wind speed near hub height. The rate of electricity generation in large wind farms containing multiple wind arrays is, therefore, constrained by the rate of kinetic energy replenishment from the atmosphere above. In recent years, a growing...



Human papillomavirus oncogenes reprogram the cervical cancer microenvironment independently of and synergistically with estrogen [Medical Sciences]

2017-10-09T11:49:06-07:00

High-risk human papillomaviruses (HPVs) infect epithelial cells and are causally associated with cervical cancer, but HPV infection is not sufficient for carcinogenesis. Previously, we reported that estrogen signaling in the stromal tumor microenvironment is associated with cervical cancer maintenance and progression. We have now determined how HPV oncogenes and estrogen...



Human SHMT inhibitors reveal defective glycine import as a targetable metabolic vulnerability of diffuse large B-cell lymphoma [Biochemistry]

2017-10-09T11:49:06-07:00

The enzyme serine hydroxymethyltransferse (SHMT) converts serine into glycine and a tetrahydrofolate-bound one-carbon unit. Folate one-carbon units support purine and thymidine synthesis, and thus cell growth. Mammals have both cytosolic SHMT1 and mitochondrial SHMT2, with the mitochondrial isozyme strongly up-regulated in cancer. Here we show genetically that dual SHMT1/2 knockout...



Opioid and orexin hedonic hotspots in rat orbitofrontal cortex and insula [Neuroscience]

2017-10-09T11:49:06-07:00

Hedonic hotspots are brain sites where particular neurochemical stimulations causally amplify the hedonic impact of sensory rewards, such as “liking” for sweetness. Here, we report the mapping of two hedonic hotspots in cortex, where mu opioid or orexin stimulations enhance the hedonic impact of sucrose taste. One hedonic hotspot was...



Molecular photoswitches mediating the strain-driven disassembly of supramolecular tubules [Chemistry]

2017-10-09T11:49:06-07:00

Chemists have created molecular machines and switches with specific mechanical responses that were typically demonstrated in solution, where mechanically relevant motion is dissipated in the Brownian storm. The next challenge consists of designing specific mechanisms through which the action of individual molecules is transmitted to a supramolecular architecture, with a...



Disruption and rescue of interareal theta phase coupling and adaptive behavior [Psychological and Cognitive Sciences]

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

Rescuing executive functions in people with neurological and neuropsychiatric disorders has been a major goal of psychology and neuroscience for decades. Innovative computer-training regimes for executive functions have made tremendous inroads, yet the positive effects of training have not always translated into improved cognitive functioning and often take many days...



Spatial organization of a model 15-member human gut microbiota established in gnotobiotic mice [Microbiology]

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

Knowledge of the spatial organization of the gut microbiota is important for understanding the physical and molecular interactions among its members. These interactions are thought to influence microbial succession, community stability, syntrophic relationships, and resiliency in the face of perturbations. The complexity and dynamism of the gut microbiota pose considerable...



Insight into the growth pattern and bone fusion of basal birds from an Early Cretaceous enantiornithine bird [Evolution]

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

Bird skeletons exhibit remarkable modifications that allow for flight. The most distinguishable features are the fusion of the bones in the hand, feet, and pelvis into composite rigid and bony structures. However, the historical origins of these avian bone fusions remain elusive because of the rarity of transitional fossils and...



UTX-guided neural crest function underlies craniofacial features of Kabuki syndrome [Genetics]

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

Kabuki syndrome, a congenital craniofacial disorder, manifests from mutations in an X-linked histone H3 lysine 27 demethylase (UTX/KDM6A) or a H3 lysine 4 methylase (KMT2D). However, the cellular and molecular etiology of histone-modifying enzymes in craniofacial disorders is unknown. We now establish Kabuki syndrome as a neurocristopathy, whereby the majority...



Maladaptive DNA repair is the ultimate contributor to the death of trimethoprim-treated cells under aerobic and anaerobic conditions [Microbiology]

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

The bactericidal effects of antibiotics are undoubtedly triggered by target-specific interactions, but there is growing evidence that an important aspect of cytotoxicity results from treatment-induced metabolic perturbations. In this study, we characterized molecular mechanisms whereby trimethoprim treatment results in cell death, using Escherichia coli as the model organism. E. coli...



Mechanistic principles underlying regulation of the actin cytoskeleton by phosphoinositides [Biochemistry]

2017-10-09T11:49:08-07:00

The actin cytoskeleton powers membrane deformation during many cellular processes, such as migration, morphogenesis, and endocytosis. Membrane phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], regulate the activities of many actin-binding proteins (ABPs), including profilin, cofilin, Dia2, N-WASP, ezrin, and moesin, but the underlying molecular mechanisms have remained elusive. Moreover, because of a...



Transcription factor ISX mediates the cross talk between diet and immunity [Physiology]

2017-10-09T11:49:08-07:00

The intestinal epithelium is a major site for the conversion of dietary β-carotene to retinaldehyde by the enzyme BCO1. The majority of retinaldehyde is further metabolized to retinol (vitamin A), esterified and packaged into triacylglycerol-rich chylomicrons for bodily distribution. Some serve on-site for the synthesis of retinoic acid, a hormone-like...



Nonequilibrium fluctuations of lipid membranes by the rotating motor protein F1F0-ATP synthase [Biophysics and Computational Biology]

2017-10-09T11:49:08-07:00

ATP synthase is a rotating membrane protein that synthesizes ATP through proton-pumping activity across the membrane. To unveil the mechanical impact of this molecular active pump on the bending properties of its lipid environment, we have functionally reconstituted the ATP synthase in giant unilamellar vesicles and tracked the membrane fluctuations...



Prebiotic stereoselective synthesis of purine and noncanonical pyrimidine nucleotide from nucleobases and phosphorylated carbohydrates [Chemistry]

2017-10-09T11:49:08-07:00

According to a current “RNA first” model for the origin of life, RNA emerged in some form on early Earth to become the first biopolymer to support Darwinism here. Threose nucleic acid (TNA) and other polyelectrolytes are also considered as the possible first Darwinian biopolymer(s). This model is being developed...



Breast tumor cell-specific knockout of Twist1 inhibits cancer cell plasticity, dissemination, and lung metastasis in mice [Medical Sciences]

2017-10-09T11:49:08-07:00

Twist1 is an epithelial–mesenchymal transition (EMT)-inducing transcription factor (TF) that promotes cell migration and invasion. To determine the intrinsic role of Twist1 in EMT and breast cancer initiation, growth, and metastasis, we developed mouse models with an oncogene-induced mammary tumor containing wild-type (WT) Twist1 or tumor cell-specific Twist1 knockout (Twist1TKO)....



Cardiovascular homeostasis dependence on MICU2, a regulatory subunit of the mitochondrial calcium uniporter [Medical Sciences]

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

Comparative analyses of transcriptional profiles from humans and mice with cardiovascular pathologies revealed consistently elevated expression of MICU2, a regulatory subunit of the mitochondrial calcium uniporter complex. To determine if MICU2 expression was cardioprotective, we produced and characterized Micu2−/− mice. Mutant mice had left atrial enlargement and Micu2−/− cardiomyocytes had...



Marine mammal population decline linked to obscured by-catch [Sustainability Science]

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

Declines of marine megafauna due to fisheries by-catch are thought to be mitigated by exclusion devices that release nontarget species. However, exclusion devices may instead conceal negative effects associated with by-catch caused by fisheries (i.e., unobserved or discarded by-catch with low postrelease survival or reproduction). We show that the decline...



Ninjurin 1 has two opposing functions in tumorigenesis in a p53-dependent manner [Medical Sciences]

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

WT p53 is critical for tumor suppression, whereas mutant p53 promotes tumor progression. Nerve injury-induced protein 1 (Ninj1) is a target of p53 and forms a feedback loop with p53 by repressing p53 mRNA translation. Here, we show that loss of Ninj1 increased mutant p53 expression and, subsequently, enhanced cell...



Multielectron, multisubstrate molecular catalysis of electrochemical reactions: Formal kinetic analysis in the total catalysis regime [Chemistry]

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

Cyclic voltammetry responses are derived for two-electron, two-step homogeneous electrocatalytic reactions in the total catalysis regime. The models developed provide a framework for extracting kinetic information from cyclic voltammograms (CVs) obtained in conditions under which the substrate or cosubstrate is consumed in a multielectron redox process, as is particularly prevalent...



M344 promotes nonamyloidogenic amyloid precursor protein processing while normalizing Alzheimer’s disease genes and improving memory [Neuroscience]

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

Alzheimer’s disease (AD) comprises multifactorial ailments for which current therapeutic strategies remain insufficient to broadly address the underlying pathophysiology. Epigenetic gene regulation relies upon multifactorial processes that regulate multiple gene and protein pathways, including those involved in AD. We therefore took an epigenetic approach where a single drug would simultaneously...



Inhibition of DAI-dependent necroptosis by the Z-DNA binding domain of the vaccinia virus innate immune evasion protein, E3 [Microbiology]

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

Vaccinia virus (VACV) encodes an innate immune evasion protein, E3, which contains an N-terminal Z-nucleic acid binding (Zα) domain that is critical for pathogenicity in mice. Here we demonstrate that the N terminus of E3 is necessary to inhibit an IFN-primed virus-induced necroptosis. VACV deleted of the Zα domain of...



Selective neutralization of IL-12 p40 monomer induces death in prostate cancer cells via IL-12-IFN-{gamma} [Immunology and Inflammation]

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

Cancer cells are adept at evading cell death, but the underlying mechanisms are poorly understood. IL-12 plays a critical role in the early inflammatory response to infection and in the generation of T-helper type 1 cells, favoring cell-mediated immunity. IL-12 is composed of two different subunits, p40 and p35. This...



Distinct ice patterns on solid surfaces with various wettabilities [Applied Physical Sciences]

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

No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions...



Pressure effects on collective density fluctuations in water and protein solutions [Biophysics and Computational Biology]

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

Neutron Brillouin scattering and molecular dynamics simulations have been used to investigate protein hydration water density fluctuations as a function of pressure. Our results show significant differences between the pressure and density dependence of collective dynamics in bulk water and in concentrated protein solutions. Pressure-induced changes in the tetrahedral order...



Visual perception as retrospective Bayesian decoding from high- to low-level features [Neuroscience]

2017-10-09T11:49:11-07:00

When a stimulus is presented, its encoding is known to progress from low- to high-level features. How these features are decoded to produce perception is less clear, and most models assume that decoding follows the same low- to high-level hierarchy of encoding. There are also theories arguing for global precedence,...



{beta}2-Adrenoceptor signaling in airway epithelial cells promotes eosinophilic inflammation, mucous metaplasia, and airway contractility [Pharmacology]

2017-10-09T11:49:11-07:00

The mostly widely used bronchodilators in asthma therapy are β2-adrenoreceptor (β2AR) agonists, but their chronic use causes paradoxical adverse effects. We have previously determined that β2AR activation is required for expression of the asthma phenotype in mice, but the cell types involved are unknown. We now demonstrate that β2AR signaling...



Perceiving social interactions in the posterior superior temporal sulcus [Neuroscience]

2017-10-09T11:49:11-07:00

Primates are highly attuned not just to social characteristics of individual agents, but also to social interactions between multiple agents. Here we report a neural correlate of the representation of social interactions in the human brain. Specifically, we observe a strong univariate response in the posterior superior temporal sulcus (pSTS)...



Broad role for YBX1 in defining the small noncoding RNA composition of exosomes [Biochemistry]

2017-10-10T10:29:17-07:00

RNA is secreted from cells enclosed within extracellular vesicles (EVs). Defining the RNA composition of EVs is challenging due to their coisolation with contaminants, lack of knowledge of the mechanisms of RNA sorting into EVs, and limitations of conventional RNA-sequencing methods. Here we present our observations using thermostable group II...



Pathogenesis of hypothyroidism-induced NAFLD is driven by intra- and extrahepatic mechanisms [Physiology]

2017-10-10T10:29:17-07:00

Hypothyroidism, a metabolic disease characterized by low thyroid hormone (TH) and high thyroid-stimulating hormone (TSH) levels in the serum, is strongly associated with nonalcoholic fatty liver disease (NAFLD). Hypothyroidism-induced NAFLD has generally been attributed to reduced TH signaling in the liver with a consequent decrease in lipid utilization. Here, we...



SMELL-S and SMELL-R: Olfactory tests not influenced by odor-specific insensitivity or prior olfactory experience [Medical Sciences]

2017-10-10T10:29:18-07:00

Smell dysfunction is a common and underdiagnosed medical condition that can have serious consequences. It is also an early biomarker of neurodegenerative diseases, including Alzheimer’s disease, where olfactory deficits precede detectable memory loss. Clinical tests that evaluate the sense of smell face two major challenges. First, human sensitivity to individual...



Production of diverse PET probes with limited resources: 24 18F-labeled compounds prepared with a single radiosynthesizer [Chemistry]

2017-10-10T10:29:18-07:00

New radiolabeled probes for positron-emission tomography (PET) are providing an ever-increasing ability to answer diverse research and clinical questions and to facilitate the discovery, development, and clinical use of drugs in patient care. Despite the high equipment and facility costs to produce PET probes, many radiopharmacies and radiochemistry laboratories use...



Molecular basis for unique specificity of human TRAF4 for platelets GPIb{beta} and GPVI [Biophysics and Computational Biology]

2017-10-10T10:29:18-07:00

Tumor necrosis factor (TNF)-receptor associated factor 4 (TRAF4), an adaptor protein with E3-ligase activity, is involved in embryogenesis, cancer initiation and progression, and platelet receptor (GPIb-IX-V complex and GPVI)-mediated signaling for reactive oxygen species (ROS) production that initiates thrombosis at arterial shears. Disruption of platelet receptors and the TRAF4 interaction...



Human papillomavirus oncoproteins induce a reorganization of epithelial-associated {gamma}{delta} T cells promoting tumor formation [Immunology and Inflammation]

2017-10-10T10:29:18-07:00

It has been shown that γδ T cells protect against the formation of squamous cell carcinoma (SCC) in several models. However, the role of γδ T cells in human papillomavirus (HPV)-associated uterine cervical SCC, the third-leading cause of death by cancer in women, is unknown. Here, we investigated the impact...



Configurational entropy measurements in extremely supercooled liquids that break the glass ceiling [Physics]

2017-10-10T10:29:18-07:00

Liquids relax extremely slowly on approaching the glass state. One explanation is that an entropy crisis, because of the rarefaction of available states, makes it increasingly arduous to reach equilibrium in that regime. Validating this scenario is challenging, because experiments offer limited resolution, while numerical studies lag more than eight...



Natural variation identifies genes affecting drought-induced abscisic acid accumulation in Arabidopsis thaliana [Plant Biology]

2017-10-10T10:29:18-07:00

Accumulation of the stress hormone abscisic acid (ABA) in response to drought and low water-potential controls many downstream acclimation mechanisms. However, mechanisms controlling ABA accumulation itself are less known. There was a 10-fold range of variation in ABA levels among nearly 300 Arabidopsis thaliana accessions exposed to the same low...