at Demographic science aids in understanding the spread and fatality rates of COVID-19 [Social Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 Governments around the world must rapidly mobilize and make difficult policy decisions to mitigate the coronavirus disease 2019 (COVID-19) pandemic. Because deaths have been concentrated at older ages, we highlight the important role of demography, particularly, how the age structure of a population may help explain differences in fatality rates... Full Article
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at 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
at Reply to Schild et al.: Antisocial personality moderates the causal influence of costly punishment on trust and trustworthiness [Social Sciences] By www.pnas.org Published On :: 2020-05-05T10:31:24-07:00 A growing literature at the intersection of personality psychology and behavioral economics investigates the interplay between personality and decision making in social dilemmas (1, 2). Engelmann et al. (3) extend prior research in this area by investigating the role of antisocial personality in the context of a trust game with... Full Article
at Requirement of the Cep57-Cep63 Interaction for Proper Cep152 Recruitment and Centriole Duplication [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Cep57 has been characterized as a component of a pericentriolar complex containing Cep63 and Cep152. Interestingly, Cep63 and Cep152 self-assemble into a pericentriolar cylindrical architecture, and this event is critical for the orderly recruitment of Plk4, a key regulator of centriole duplication. However, the way in which Cep57 interacts with the Cep63-Cep152 complex and contributes to the structure and function of Cep63-Cep152 self-assembly remains unknown. We demonstrate that Cep57 interacts with Cep63 through N-terminal motifs and associates with Cep152 via Cep63. Three-dimensional structured illumination microscopy (3D-SIM) analyses suggested that the Cep57-Cep63-Cep152 complex is concentrically arranged around a centriole in a Cep57-in and Cep152-out manner. Cep57 mutant cells defective in Cep63 binding exhibited improper Cep63 and Cep152 localization and impaired Sas6 recruitment for procentriole assembly, proving the significance of the Cep57-Cep63 interaction. Intriguingly, Cep63 fused to a microtubule (MT)-binding domain of Cep57 functioned in concert with Cep152 to assemble around stabilized MTs in vitro. Thus, Cep57 plays a key role in architecting the Cep63-Cep152 assembly around centriolar MTs and promoting centriole biogenesis. This study may offer a platform to investigate how the organization and function of the pericentriolar architecture are altered by disease-associated mutations found in the Cep57-Cep63-Cep152 complex. Full Article
at E2F6-Mediated Downregulation of MIR22HG Facilitates the Progression of Laryngocarcinoma by Targeting the miR-5000-3p/FBXW7 Axis [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Recently, abundant evidence has clarified that long noncoding RNAs (lncRNAs) play an oncogenic or anticancer role in the tumorigenesis and development of diverse human cancers. Described as a crucial regulator in some cancers, MIR22HG has not yet been studied in laryngocarcinoma and therefore the underlying regulatory role of MIR22HG in laryngocarcinoma is worth detecting. In this study, MIR22HG expression in laryngocarcinoma cells was confirmed to be downregulated, and upregulated MIR22HG expression led to suppressive effects on laryngocarcinoma cell proliferation and migration. Molecular mechanism assays revealed that MIR22HG sponges miR-5000-3p in laryngocarcinoma cells. Besides, decreased expression of miR-5000-3p suppressed laryngocarcinoma cell proliferation and migration. Moreover, the FBXW7 gene was reported to be a downstream target gene of miR-5000-3p in laryngocarcinoma cells. More importantly, rescue assays verified that FBXW7 depletion or miR-5000-3p upregulation countervailed the repressive effects of MIR22HG overexpression on laryngocarcinoma progression. In addition, E2F6 was proved to be capable of inhibiting MIR22HG transcription in laryngocarcinoma cells. To sum up, E2F6-induced downregulation of MIR22HG promotes laryngocarcinoma progression through the miR-5000-3p/FBXW7 axis. Full Article
at AKT Regulates Mitotic Progression of Mammalian Cells by Phosphorylating MASTL, Leading to Protein Phosphatase 2A Inactivation [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Microtubule-associated serine/threonine kinase like (MASTL), also known as Greatwall (Gwl) kinase, has an important role in the regulation of mitosis. By inhibiting protein phosphatase 2A (PP2A), it plays a crucial role in activating one of the most important mitotic kinases, known as cyclin-dependent kinase 1 (CDK1). MASTL has been seen to be upregulated in various types of cancers and is also involved in tumor recurrence. It is activated by CDK1 through phosphorylations in the activation/T-loop, but the complete mechanism of its activation is still unclear. Here, we report that AKT phosphorylates MASTL at residue T299, which plays a critical role in its activation. Our results suggest that AKT increases CDK1-mediated phosphorylation and hence the activity of MASTL, which, in turn, promotes mitotic progression through PP2A inhibition. We also show that the oncogenic potential of AKT is augmented by MASTL activation, since AKT-mediated proliferation in colorectal cell lines can be attenuated by inhibiting and/or silencing MASTL. In brief, we report that AKT plays an important role in the progression of mitosis in mammalian cells and that it does so through the phosphorylation and activation of MASTL. Full Article
at Determining the Bioenergetic Capacity for Fatty Acid Oxidation in the Mammalian Nervous System [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 The metabolic state of the brain can greatly impact neurologic function. Evidence of this includes the therapeutic benefit of a ketogenic diet in neurologic diseases, including epilepsy. However, brain lipid bioenergetics remain largely uncharacterized. The existence, capacity, and relevance of mitochondrial fatty acid β-oxidation (FAO) in the brain are highly controversial, with few genetic tools available to evaluate the question. We have provided evidence for the capacity of brain FAO using a pan-brain-specific conditional knockout (KO) mouse incapable of FAO due to the loss of carnitine palmitoyltransferase 2, the product of an obligate gene for FAO (CPT2B–/–). Loss of central nervous system (CNS) FAO did not result in gross neuroanatomical changes or systemic differences in metabolism. Loss of CPT2 in the brain did not result in robustly impaired behavior. We demonstrate by unbiased and targeted metabolomics that the mammalian brain oxidizes a substantial quantity of long-chain fatty acids in vitro and in vivo. Loss of CNS FAO results in robust accumulation of long-chain acylcarnitines in the brain, suggesting that the mammalian brain mobilizes fatty acids for their oxidation, irrespective of diet or metabolic state. Together, these data demonstrate that the mammalian brain oxidizes fatty acids under normal circumstances with little influence from or on peripheral tissues. Full Article
at Correction for Dietz et al., "2019 Novel Coronavirus (COVID-19) Pandemic: Built Environment Considerations To Reduce Transmission" By msystems.asm.org Published On :: 2020-05-05T07:30:12-07:00 Full Article
at SARS-CoV-2 and ORF3a: Nonsynonymous Mutations, Functional Domains, and Viral Pathogenesis By msystems.asm.org Published On :: 2020-05-05T07:30:12-07:00 ABSTRACT The effect of the rapid accumulation of nonsynonymous mutations on the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not yet known. The 3a protein is unique to SARS-CoV and is essential for disease pathogenesis. Our study aimed at determining the nonsynonymous mutations in the 3a protein in SARS-CoV-2 and determining and characterizing the protein’s structure and spatial orientation in comparison to those of 3a in SARS-CoV. A total of 51 different nonsynonymous amino acid substitutions were detected in the 3a proteins among 2,782 SARS-CoV-2 strains. We observed microclonality within the ORF3a gene tree defined by nonsynonymous mutations separating the isolates into distinct subpopulations. We detected and identified six functional domains (I to VI) in the SARS-CoV-2 3a protein. The functional domains were linked to virulence, infectivity, ion channel formation, and virus release. Our study showed the importance of conserved functional domains across the species barrier and revealed the possible role of the 3a protein in the viral life cycle. Observations reported in this study merit experimental confirmation. IMPORTANCE At the surge of the coronavirus disease 2019 (COVID-19) pandemic, we detected and identified six functional domains (I to VI) in the SARS-CoV-2 3a protein. Our analysis showed that the functional domains were linked to virulence, infectivity, ion channel formation, and virus release in SARS-CoV-2 3a. Our study also revealed the functional importance of conserved domains across the species barrier. Observations reported in this study merit experimental confirmation. Full Article
at Isolation and Characterization of the Novel Phage JD032 and Global Transcriptomic Response during JD032 Infection of Clostridioides difficile Ribotype 078 By msystems.asm.org Published On :: 2020-05-05T07:30:12-07:00 ABSTRACT Insights into the interaction between phages and their bacterial hosts are crucial for the development of phage therapy. However, only one study has investigated global gene expression of Clostridioides (formerly Clostridium) difficile carrying prophage, and transcriptional reprogramming during lytic infection has not been studied. Here, we presented the isolation, propagation, and characterization of a newly discovered 35,109-bp phage, JD032, and investigated the global transcriptomes of both JD032 and C. difficile ribotype 078 (RT078) strain TW11 during JD032 infection. Transcriptome sequencing (RNA-seq) revealed the progressive replacement of bacterial host mRNA with phage transcripts. The expressed genes of JD032 were clustered into early, middle, and late temporal categories that were functionally similar. Specifically, a gene (JD032_orf016) involved in the lysis-lysogeny decision was identified as an early expression gene. Only 17.7% (668/3,781) of the host genes were differentially expressed, and more genes were downregulated than upregulated. The expression of genes involved in host macromolecular synthesis (DNA/RNA/proteins) was altered by JD032 at the level of transcription. In particular, the expression of the ropA operon was downregulated. Most noteworthy is that the gene expression of some antiphage systems, including CRISPR-Cas, restriction-modification, and toxin-antitoxin systems, was suppressed by JD032 during infection. In addition, bacterial sporulation, adhesion, and virulence factor genes were significantly downregulated. This study provides the first description of the interaction between anaerobic spore-forming bacteria and phages during lytic infection and highlights new aspects of C. difficile phage-host interactions. IMPORTANCE C. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile. Full Article
at Family Medicine Certification Longitudinal Assessment after One Year By www.jabfm.org Published On :: 2020-03-16T09:31:37-07:00 Full Article