o Intertwined signatures of desiccation and drought tolerance in grasses [Plant Biology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Grasses are among the most resilient plants, and some can survive prolonged desiccation in semiarid regions with seasonal rainfall. However, the genetic elements that distinguish grasses that are sensitive versus tolerant to extreme drying are largely unknown. Here, we leveraged comparative genomic approaches with the desiccation-tolerant grass Eragrostis nindensis and... Full Article
o Single-cell O2 exchange imaging shows that cytoplasmic diffusion is a dominant barrier to efficient gas transport in red blood cells [Physiology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Disorders of oxygen transport are commonly attributed to inadequate carrying capacity (anemia) but may also relate to inefficient gas exchange by red blood cells (RBCs), a process that is poorly characterized yet assumed to be rapid. Without direct measurements of gas exchange at the single-cell level, the barriers to O2... Full Article
o Extent of Fermi-surface reconstruction in the high-temperature superconductor HgBa2CuO4+{delta} [Physics] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 High magnetic fields have revealed a surprisingly small Fermi surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A crucial issue concerns the doping extent of such a state and its relationship to the principal pseudogap and... Full Article
o Detecting electronic coherences by time-domain high-harmonic spectroscopy [Physics] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Ultrafast spectroscopy is capable of monitoring electronic and vibrational states. For electronic states a few eV apart, an X-ray laser source is required. We propose an alternative method based on the time-domain high-order harmonic spectroscopy where a coherent superposition of the electronic states is first prepared by the strong optical... Full Article
o Reversal of hyperactive subthalamic circuits differentially mitigates pain hypersensitivity phenotypes in parkinsonian mice [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Although pain is a prevalent nonmotor symptom in Parkinson’s disease (PD), it is undertreated, in part because of our limited understanding of the underlying mechanisms. Considering that the basal ganglia are implicated in pain sensation, and that their synaptic outputs are controlled by the subthalamic nucleus (STN), we hypothesized that... Full Article
o In utero MRI identifies consequences of early-gestation alcohol drinking on fetal brain development in rhesus macaques [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 One factor that contributes to the high prevalence of fetal alcohol spectrum disorder (FASD) is binge-like consumption of alcohol before pregnancy awareness. It is known that treatments are more effective with early recognition of FASD. Recent advances in retrospective motion correction for the reconstruction of three-dimensional (3D) fetal brain MRI... Full Article
o Covert sleep-related biological processes are revealed by probabilistic analysis in Drosophila [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Sleep pressure and sleep depth are key regulators of wake and sleep. Current methods of measuring these parameters in Drosophila melanogaster have low temporal resolution and/or require disrupting sleep. Here we report analysis tools for high-resolution, noninvasive measurement of sleep pressure and depth from movement data. Probability of initiating activity,... Full Article
o Loss of nucleus accumbens low-frequency fluctuations is a signature of chronic pain [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Chronic pain is a highly prevalent disease with poorly understood pathophysiology. In particular, the brain mechanisms mediating the transition from acute to chronic pain remain largely unknown. Here, we identify a subcortical signature of back pain. Specifically, subacute back pain patients who are at risk for developing chronic pain exhibit... Full Article
o A viral toolkit for recording transcription factor-DNA interactions in live mouse tissues [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Transcription factors (TFs) enact precise regulation of gene expression through site-specific, genome-wide binding. Common methods for TF-occupancy profiling, such as chromatin immunoprecipitation, are limited by requirement of TF-specific antibodies and provide only end-point snapshots of TF binding. Alternatively, TF-tagging techniques, in which a TF is fused to a DNA-modifying enzyme... Full Article
o Cannabinoid exposure in rat adolescence reprograms the initial behavioral, molecular, and epigenetic response to cocaine [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The initial response to an addictive substance can facilitate repeated use: That is, individuals experiencing more positive effects are more likely to use that drug again. Increasing evidence suggests that psychoactive cannabinoid use in adolescence enhances the behavioral effects of cocaine. However, despite the behavioral data, there is no neurobiological... Full Article
o A minor population of macrophage-tropic HIV-1 variants is identified in recrudescing viremia following analytic treatment interruption [Microbiology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 HIV-1 persists in cellular reservoirs that can reignite viremia if antiretroviral therapy (ART) is interrupted. Therefore, insight into the nature of those reservoirs may be revealed from the composition of recrudescing viremia following treatment cessation. A minor population of macrophage-tropic (M-tropic) viruses was identified in a library of recombinant viruses... Full Article
o Transposon mobilization in the human fungal pathogen Cryptococcus is mutagenic during infection and promotes drug resistance in vitro [Microbiology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 When transitioning from the environment, pathogenic microorganisms must adapt rapidly to survive in hostile host conditions. This is especially true for environmental fungi that cause opportunistic infections in immunocompromised patients since these microbes are not well adapted human pathogens. Cryptococcus species are yeastlike fungi that cause lethal infections, especially in... Full Article
o Triptolide suppresses IDH1-mutated malignancy via Nrf2-driven glutathione metabolism [Medical Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Isocitrate dehydrogenase (IDH) mutation is a common genetic abnormality in human malignancies characterized by remarkable metabolic reprogramming. Our present study demonstrated that IDH1-mutated cells showed elevated levels of reactive oxygen species and higher demands on Nrf2-guided glutathione de novo synthesis. Our findings showed that triptolide, a diterpenoid epoxide from Tripterygium... Full Article
o Development of a therapeutic anti-HtrA1 antibody and the identification of DKK3 as a pharmacodynamic biomarker in geographic atrophy [Medical Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Genetic polymorphisms in the region of the trimeric serine hydrolase high-temperature requirement 1 (HTRA1) are associated with increased risk of age-related macular degeneration (AMD) and disease progression, but the precise biological function of HtrA1 in the eye and its contribution to disease etiologies remain undefined. In this study, we have... Full Article
o Inner Workings: Molecular biologists offer “wartime service” in the effort to test for COVID-19 [Medical Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 As the novel coronavirus spreads, communities across the United States are struggling to offer public testing. The need is urgent. Testing got off to a delayed start in the United States as a result of technical missteps and a slow response from government officials. Now cities across the country are... Full Article
o A genome-wide association study identifies key modulators of complement factor H binding to malondialdehyde-epitopes [Immunology and Inflammation] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Genetic variants within complement factor H (CFH), a major alternative complement pathway regulator, are associated with the development of age-related macular degeneration (AMD) and other complementopathies. This is explained with the reduced binding of CFH or its splice variant factor H-like protein 1 (FHL-1) to self-ligands or altered self-ligands (e.g.,... Full Article
o Starvation and antimetabolic therapy promote cytokine release and recruitment of immune cells [Immunology and Inflammation] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Cellular starvation is typically a consequence of tissue injury that disrupts the local blood supply but can also occur where cell populations outgrow the local vasculature, as observed in solid tumors. Cells react to nutrient deprivation by adapting their metabolism, or, if starvation is prolonged, it can result in cell... Full Article
o Landscape analysis of adȷacent gene rearrangements reveals BCL2L14-ETV6 gene fusions in more aggressive triple-negative breast cancer [Genetics] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Triple-negative breast cancer (TNBC) accounts for 10 to 20% of breast cancer, with chemotherapy as its mainstay of treatment due to lack of well-defined targets, and recent genomic sequencing studies have revealed a paucity of TNBC-specific mutations. Recurrent gene fusions comprise a class of viable genetic targets in solid tumors;... Full Article
o Ammonia emission abatement does not fully control reduced forms of nitrogen deposition [Environmental Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Human activities and population growth have increased the natural burden of reactive nitrogen (N) in the environment. Excessive N deposition on Earth’s surface leads to adverse feedbacks on ecosystems and humans. Similar to that of air pollution, emission control is recognized as an efficient means to control acid deposition. Control... Full Article
o A nonlinear beam model of photomotile structures [Engineering] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Actuation remains a significant challenge in soft robotics. Actuation by light has important advantages: Objects can be actuated from a distance, distinct frequencies can be used to actuate and control distinct modes with minimal interference, and significant power can be transmitted over long distances through corrosion-free, lightweight fiber optic cables.... Full Article
o Reconciling global priorities for conserving biodiversity habitat [Ecology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Degradation and loss of natural habitat is the major driver of the current global biodiversity crisis. Most habitat conservation efforts to date have targeted small areas of highly threatened habitat, but emerging debate suggests that retaining large intact natural systems may be just as important. We reconcile these perspectives by... Full Article
o Aerosol-photolysis interaction reduces particulate matter during wintertime haze events [Earth, Atmospheric, and Planetary Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Aerosol–radiation interaction (ARI) plays a significant role in the accumulation of fine particulate matter (PM2.5) by stabilizing the planetary boundary layer and thus deteriorating air quality during haze events. However, modification of photolysis by aerosol scattering or absorbing solar radiation (aerosol–photolysis interaction or API) alters the atmospheric oxidizing capacity, decreases... Full Article
o Large H2O solubility in dense silica and its implications for the interiors of water-rich planets [Earth, Atmospheric, and Planetary Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Sub-Neptunes are common among the discovered exoplanets. However, lack of knowledge on the state of matter in H2O-rich setting at high pressures and temperatures (P−T) places important limitations on our understanding of this planet type. We have conducted experiments for reactions between SiO2 and H2O as archetypal materials for rock... Full Article
o Improved surrogates in inertial confinement fusion with manifold and cycle consistencies [Computer Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Neural networks have become the method of choice in surrogate modeling because of their ability to characterize arbitrary, high-dimensional functions in a data-driven fashion. This paper advocates for the training of surrogates that are 1) consistent with the physical manifold, resulting in physically meaningful predictions, and 2) cyclically consistent with... Full Article
o Metal ions confinement defines the architecture of G-quartet, G-quadruplex fibrils and their assembly into nematic tactoids [Chemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 G-quadruplex, assembled from a square array of guanine (G) molecules, is an important structure with crucial biological roles in vivo but also a versatile template for ordered functional materials. Although the understanding of G-quadruplex structures is the focus of numerous studies, little is known regarding the control of G-quartet stacking... Full Article
o Direct kinetic measurements and theoretical predictions of an isoprene-derived Criegee intermediate [Chemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Isoprene has the highest emission into Earth’s atmosphere of any nonmethane hydrocarbon. Atmospheric processing of alkenes, including isoprene, via ozonolysis leads to the formation of zwitterionic reactive intermediates, known as Criegee intermediates (CIs). Direct studies have revealed that reactions involving simple CIs can significantly impact the tropospheric oxidizing capacity, enhance... Full Article
o Matrix mechanotransduction mediated by thrombospondin-1/integrin/YAP in the vascular remodeling [Cell Biology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The extracellular matrix (ECM) initiates mechanical cues that activate intracellular signaling through matrix–cell interactions. In blood vessels, additional mechanical cues derived from the pulsatile blood flow and pressure play a pivotal role in homeostasis and disease development. Currently, the nature of the cues from the ECM and their interaction with... Full Article
o MTV proteins unveil ER- and microtubule-associated compartments in the plant vacuolar trafficking pathway [Cell Biology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The factors and mechanisms involved in vacuolar transport in plants, and in particular those directing vesicles to their target endomembrane compartment, remain largely unknown. To identify components of the vacuolar trafficking machinery, we searched for Arabidopsis modified transport to the vacuole (mtv) mutants that abnormally secrete the synthetic vacuolar cargo... Full Article
o Cryo-EM structure of C9ORF72-SMCR8-WDR41 reveals the role as a GAP for Rab8a and Rab11a [Biochemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 A massive intronic hexanucleotide repeat (GGGGCC) expansion in C9ORF72 is a genetic origin of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recently, C9ORF72, together with SMCR8 and WDR41, has been shown to regulate autophagy and function as Rab GEF. However, the precise function of C9ORF72 remains unclear. Here, we... Full Article
o Structural basis for Zika envelope domain III recognition by a germline version of a recurrent neutralizing antibody [Biochemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Recent epidemics demonstrate the global threat of Zika virus (ZIKV), a flavivirus transmitted by mosquitoes. Although infection is usually asymptomatic or mild, newborns of infected mothers can display severe symptoms, including neurodevelopmental abnormalities and microcephaly. Given the large-scale spread, symptom severity, and lack of treatment or prophylaxis, a safe and... Full Article
o Regulatory mechanism for the transmembrane receptor that mediates bidirectional vitamin A transport [Biochemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Vitamin A has diverse biological functions and is essential for human survival at every point from embryogenesis to adulthood. Vitamin A and its derivatives have been used to treat human diseases including vision diseases, skin diseases, and cancer. Both insufficient and excessive vitamin A uptake are detrimental, but how its... Full Article
o High-throughput antibody screening from complex matrices using intact protein electrospray mass spectrometry [Biochemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Toward the goal of increasing the throughput of high-resolution mass characterization of intact antibodies, we developed a RapidFire–mass spectrometry (MS) assay using electrospray ionization. We achieved unprecedented screening throughput as fast as 15 s/sample, which is an order of magnitude improvement over conventional liquid chromatography (LC)-MS approaches. The screening enabled... Full Article
o Moderation of mitochondrial respiration mitigates metabolic syndrome of aging [Biochemistry] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Deregulation of mitochondrial dynamics leads to the accumulation of oxidative stress and unhealthy mitochondria; consequently, this accumulation contributes to premature aging and alterations in mitochondria linked to metabolic complications. We postulate that restrained mitochondrial ATP synthesis might alleviate age-associated disorders and extend healthspan in mammals. Herein, we prepared a previously... Full Article
o New HST data and modeling reveal a massive planetesimal collision around Fomalhaut [Astronomy] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008. However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the infrared, and its orbit appears to cross the debris ring around the star without... Full Article
o Emergence of self-organized multivortex states in flocks of active rollers [Applied Physical Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Active matter, both synthetic and biological, demonstrates complex spatiotemporal self-organization and the emergence of collective behavior. A coherent rotational motion, the vortex phase, is of great interest because of its ability to orchestrate well-organized motion of self-propelled particles over large distances. However, its generation without geometrical confinement has been a... Full Article
o Mimicry of a biophysical pathway leads to diverse pollen-like surface patterns [Applied Physical Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 A ubiquitous structural feature in biological systems is texture in extracellular matrix that gains functions when hardened, for example, cell walls, insect scales, and diatom tests. Here, we develop patterned liquid crystal elastomer (LCE) particles by recapitulating the biophysical patterning mechanism that forms pollen grain surfaces. In pollen grains, a... Full Article
o Infant behavioral inhibition predicts personality and social outcomes three decades later [Anthropology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Does infant temperament predict adult personality and life-course patterns? To date, there is scant evidence examining relations between child temperament and adult outcomes, and extant research has relied on limited methods for measuring temperament such as maternal report. This prospective longitudinal study followed a cohort of infants (n = 165)... Full Article
o Molecular and isotopic evidence for milk, meat, and plants in prehistoric eastern African herder food systems [Anthropology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The development of pastoralism transformed human diets and societies in grasslands worldwide. The long-term success of cattle herding in Africa has been sustained by dynamic food systems, consumption of a broad range of primary and secondary livestock products, and the evolution of lactase persistence (LP), which allows digestion of lactose... Full Article
o Optimizing Rhizobium-legume symbioses by simultaneous measurement of rhizobial competitiveness and N2 fixation in nodules [Agricultural Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Legumes tend to be nodulated by competitive rhizobia that do not maximize nitrogen (N2) fixation, resulting in suboptimal yields. Rhizobial nodulation competitiveness and effectiveness at N2 fixation are independent traits, making their measurement extremely time-consuming with low experimental throughput. To transform the experimental assessment of rhizobial competitiveness and effectiveness, we... Full Article
o Metrics that matter for assessing the ocean biological carbon pump [Environmental Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The biological carbon pump (BCP) comprises wide-ranging processes that set carbon supply, consumption, and storage in the oceans’ interior. It is becoming increasingly evident that small changes in the efficiency of the BCP can significantly alter ocean carbon sequestration and, thus, atmospheric CO2 and climate, as well as the functioning... Full Article
o Loss of the neural-specific BAF subunit ACTL6B relieves repression of early response genes and causes recessive autism [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Synaptic activity in neurons leads to the rapid activation of genes involved in mammalian behavior. ATP-dependent chromatin remodelers such as the BAF complex contribute to these responses and are generally thought to activate transcription. However, the mechanisms keeping such “early activation” genes silent have been a mystery. In the course... Full Article
o PCARE and WASF3 regulate ciliary F-actin assembly that is required for the initiation of photoreceptor outer segment disk formation [Genetics] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The outer segments (OS) of rod and cone photoreceptor cells are specialized sensory cilia that contain hundreds of opsin-loaded stacked membrane disks that enable phototransduction. The biogenesis of these disks is initiated at the OS base, but the driving force has been debated. Here, we studied the function of the... Full Article
o Water lilies, loss of woodiness, and model systems [Plant Biology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The delicate necklace of threaded petals from the tomb of Rameses II, midnineteenth century glass houses built for the newly discovered Victoria amazonica, and Monet’s giant canvases in the Musée de l'Orangerie all testify to a deep human attraction to water lilies: beguiling plants with showy flowers that seem to... Full Article
o Turning up the heat in turbulent thermal convection [Applied Physical Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Convection is buoyancy-driven flow resulting from unstable density stratification in the presence of a gravitational field. Beyond convection’s central role in myriad engineering heat transfer applications, it underlies many of nature’s dynamical designs on larger-than-human scales. For example, solar heating of Earth’s surface generates buoyancy forces that cause the winds... Full Article
o Bringing light to ER contacts and a new phase in organelle communication [Cell Biology] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Functioning cells depend on the outward-facing plasma membrane (PM) effectively contacting the endoplasmic reticulum (ER), which serves as a central hub for contacts with mitochondria and other intracellular organelles. The contact sites are critical to intracellular communication because they mediate intermembrane exchange of lipids, ions, and other small molecules that... Full Article
o Seasonal timing adaptation across the geographic range of Arabidopsis thaliana [Evolution] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 The most fundamental genetic program of an annual plant defines when to grow and reproduce and when to remain dormant in the soil as a seed. With the right timing, plants can even live in hostile regions with only a few months of growth-favorable abundant rains and mild temperatures. To... Full Article
o Closing the gap between mind and brain with the dynamic connectome [Neuroscience] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 At the pinnacle of the 17th century scientific revolution, René Descartes, the father of modern philosophy, published his monumental Meditations on First Philosophy (1), in which he proposed a division between soul and body—mind and brain—with the former in charge of our thoughts and conscious decisions (res cogitans) and the... Full Article
o Profile of Xiaowei Zhuang, winner of the 2020 Vilcek Prize in Biomedical Science [Profiles] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 In 2006, the New York City-based Vilcek Foundation created an annual prize program for foreign-born biomedical scientists who have made major contributions to their fields while living and working in the United States. The founders, themselves immigrants from Czechoslovakia, established the program to raise public awareness of the indispensable role... Full Article
o Reply to Bowling: How specific emotions are primary in subjective experience [Social Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Our study in PNAS (1) applies a mathematically based framework to the study of reported emotional experience evoked by music in the United States and China. Germane to theoretical debate, our methods reveal how specific emotions such as “triumph” are more primary across cultures than valence and arousal, a finding... Full Article
o Claims of categorical primacy for musical affect are confounded by using language as a measure [Social Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Cowen et al. (1) leverage modern gains in data science to describe impressive cross-cultural similarities in the perception of musical affect and do so in unprecedented detail. Their approach is innovative and fundamentally empirical. As such, it should have important applications for prediction in the field of affective computing, which... Full Article