Evolution and epidemic spread of SARS-CoV-2 in Brazil
Brazil currently has one of the fastest-growing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemics in the world. Because of limited available data, assessments of the impact of nonpharmaceutical interventions (NPIs) on this virus spread remain challenging. Using a mobility-driven transmission model, we show that NPIs reduced the reproduction number from >3 to 1 to 1.6 in São Paulo and Rio de Janeiro. Sequencing of 427 new genomes and analysis of a geographically representative...
Thu Sep 03, 2020 20:39
Coronavirus disease 2019 (COVID-19) represents a global crisis, yet major knowledge gaps remain about human immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We analyzed immune responses in 76 COVID-19 patients and 69 healthy individuals from Hong Kong and Atlanta, Georgia, United States. In the peripheral blood mononuclear cells (PBMCs) of COVID-19 patients, we observed reduced expression of human leukocyte antigen class DR (HLA-DR) and proinflammatory cytokines by myeloid...
Thu Sep 03, 2020 20:39
Sleep and wakefulness are homeostatically regulated by a variety of factors, including adenosine. However, how neural activity underlying the sleep-wake cycle controls adenosine release in the brain remains unclear. Using a newly developed genetically encoded adenosine sensor, we found an activity-dependent rapid increase in the concentration of extracellular adenosine in mouse basal forebrain (BF), a critical region controlling sleep and wakefulness. Although the activity of both BF cholinergic...
Thu Sep 03, 2020 20:39
Recent mass measurements of light atomic nuclei in Penning traps have indicated possible inconsistencies in closely related physical constants such as the proton-electron and deuteron-proton mass ratios. These quantities also influence the predicted vibrational spectrum of the deuterated molecular hydrogen ion (HD+) in its electronic ground state. We used Doppler-free two-photon laser spectroscopy to measure the frequency of the v = 0->9 overtone transition (v, vibrational quantum number) of this...
Thu Sep 03, 2020 20:39
Vertebrates vary in their ability to regenerate, and the genetic mechanisms underlying such disparity remain elusive. Comparative epigenomic profiling and single-cell sequencing of two related teleost fish uncovered species-specific and evolutionarily conserved genomic responses to regeneration. The conserved response revealed several regeneration-responsive enhancers (RREs), including an element upstream to inhibin beta A (inhba), a known effector of vertebrate regeneration. This element activated...
Thu Sep 03, 2020 20:39
The de novo design of proteins that bind highly functionalized small molecules represents a great challenge. To enable computational design of binders, we developed a unit of protein structure—a van der Mer (vdM)—that maps the backbone of each amino acid to statistically preferred positions of interacting chemical groups. Using vdMs, we designed six de novo proteins to bind the drug apixaban; two bound with low and submicromolar affinity. X-ray crystallography and mutagenesis confirmed a structure...
Thu Sep 03, 2020 20:39
The biogeochemical silicon cycle influences global primary productivity and carbon cycling, yet changes in silicon sources and cycling during long-term development of terrestrial ecosystems remain poorly understood. Here, we show that terrestrial silicon cycling shifts from pedological to biological control during long-term ecosystem development along 2-million-year soil chronosequences in Western Australia. Silicon availability is determined by pedogenic silicon in young soils and recycling of plant-derived...
Thu Sep 03, 2020 20:39
Autophagosomes form de novo in a manner that is incompletely understood. Particularly enigmatic are autophagy-related protein 9 (Atg9)–containing vesicles that are required for autophagy machinery assembly but do not supply the bulk of the autophagosomal membrane. In this study, we reconstituted autophagosome nucleation using recombinant components from yeast. We found that Atg9 proteoliposomes first recruited the phosphatidylinositol 3-phosphate kinase complex, followed by Atg21, the Atg2-Atg18...
Thu Sep 03, 2020 20:39
Immigration and globalization have spurred interest in the effects of ethnic diversity in Western societies. Most scholars focus on whether diversity undermines trust, social capital, and collective goods provision. However, the type of prosociality that helps heterogeneous societies function is different from the in-group solidarity that glues homogeneous communities together. Social cohesion in multiethnic societies depends on whether prosocial behavior extends beyond close-knit networks and in-group...
Thu Sep 03, 2020 20:39
Millions of the world’s poorest people now live in middle-income democracies that, in theory, could use their resources to end extreme poverty. However, citizens in those countries have not succeeded in using the vote to ensure adequate progressive redistribution. Interventions aiming to provide the economically vulnerable with needed resources must go beyond assisting them directly, they must also improve democratic institutions so that vulnerable populations themselves can push their representatives...
Thu Sep 03, 2020 20:39
If the end of the 20th century was defined by the relatively widespread acceptance of democracy, the second decade of the 21st century is marked by concerns about backsliding in new and established democracies alike and by a notable decline in foreign support for democracy around the world. As democracy’s global tailwinds shift to headwinds, scholars have an opportunity to better understand how experience with even superficial forms of democratic institutions across a diverse set of contexts influences...
Thu Sep 03, 2020 20:39
A key step in translational initiation is the recruitment of the 43S preinitiation complex by the cap-binding complex [eukaryotic initiation factor 4F (eIF4F)] at the 5' end of messenger RNA (mRNA) to form the 48S initiation complex (i.e., the 48S). The 48S then scans along the mRNA to locate a start codon. To understand the mechanisms involved, we used cryo–electron microscopy to determine the structure of a reconstituted human 48S. The structure reveals insights into early events of translation...
Thu Sep 03, 2020 20:39
Digital media are critical for contemporary activism—even low-effort "clicktivism" is politically consequential and contributes to offline participation. We argue that in the United States and throughout the industrialized West, left- and right-wing activists use digital and legacy media differently to achieve political goals. Although left-wing actors operate primarily through "hashtag activism" and offline protest, right-wing activists manipulate legacy media, migrate to alternative platforms,...
Thu Sep 03, 2020 20:39
Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems can disrupt the disk. Theoretical models predict that if the disk is misaligned with the orbital plane of the stars, the disk should warp and break into precessing rings, a phenomenon known as disk tearing. We present observations of the triple-star system GW Orionis, finding evidence for disk tearing. Our images show an eccentric ring that is...
Thu Sep 03, 2020 20:39
Average and extreme temperatures will increase in the near future, but how such shifts will affect mortality in natural populations is still unclear. We used a dynamic model to predict mortality under variable temperatures on the basis of heat tolerance laboratory measurements. Theoretical lethal temperatures for 11 Drosophila species under different warming conditions were virtually indistinguishable from empirical results. For Drosophila in the field, daily mortality predicted from ambient temperature...
Thu Sep 03, 2020 20:39
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the current coronavirus disease 2019 (COVID-19) pandemic. A major virulence factor of SARS-CoVs is the nonstructural protein 1 (Nsp1), which suppresses host gene expression by ribosome association. Here, we show that Nsp1 from SARS-CoV-2 binds to the 40S ribosomal subunit, resulting in shutdown of messenger RNA (mRNA) translation both in vitro and in cells. Structural analysis by cryo–electron microscopy of in...
Thu Sep 03, 2020 20:39
The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds angiotensin-converting enzyme 2 (ACE2) on host cells to initiate entry, and soluble ACE2 is a therapeutic candidate that neutralizes infection by acting as a decoy. By using deep mutagenesis, mutations in ACE2 that increase S binding are found across the interaction surface, in the asparagine 90–glycosylation motif and at buried sites. The mutational landscape provides a blueprint for understanding the specificity...
Thu Sep 03, 2020 20:39
Coronavirus disease 2019 (COVID-19) is currently a global pandemic, but human immune responses to the virus remain poorly understood. We used high-dimensional cytometry to analyze 125 COVID-19 patients and compare them with recovered and healthy individuals. Integrated analysis of ~200 immune and ~50 clinical features revealed activation of T cell and B cell subsets in a proportion of patients. A subgroup of patients had T cell activation characteristic of acute viral infection and plasmablast responses...
Thu Sep 03, 2020 20:39
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