Catálogo de publicaciones - revistas

<jats:title>Immune profiling of COVID-19 patients</jats:title> <jats:p> Coronavirus disease 2019 (COVID-19) has affected millions of people globally, yet how the human immune system responds to and influences COVID-19 severity remains unclear. Mathew <jats:italic>et al.</jats:italic> present a comprehensive atlas of immune modulation associated with COVID-19. They performed high-dimensional flow cytometry of hospitalized COVID-19 patients and found three prominent and distinct immunotypes that are related to disease severity and clinical parameters. Arunachalam <jats:italic>et al.</jats:italic> report a systems biology approach to assess the immune system of COVID-19 patients with mild-to-severe disease. These studies provide a compendium of immune cell information and roadmaps for potential therapeutic interventions. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc8511">eabc8511</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1210" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abc6261">1210</jats:related-article> </jats:p>

<jats:title>Finding the start</jats:title> <jats:p> Eukaryotic translation involves many players in a dynamic and well-orchestrated process. A 43 <jats:italic>S</jats:italic> preinitiation complex (PIC) comprises the 40 <jats:italic>S</jats:italic> ribosomal subunit; initiation factors, including the eIF3 complex, which is known to play a key role; and the transfer RNA used for translation initiation. The PIC is recruited to the cap-binding complex eIF4F at the 5′ end of messenger RNA (mRNA) to form a 48 <jats:italic>S</jats:italic> complex that scans along the mRNA for a start codon. Brito Querido <jats:italic>et al.</jats:italic> determined the structure of a reconstituted human 48 <jats:italic>S</jats:italic> complex using cryo–electron microscopy. They found that eIF4F binds to eIF3 near the exit site of the ribosome. This positioning suggests that downstream mRNA is likely pulled through the 40 <jats:italic>S</jats:italic> subunit to find the start codon. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1220" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba4904">1220</jats:related-article> </jats:p>

<jats:title>A new tool in the protein design toolbox</jats:title> <jats:p>Protein design can compute protein folds from first principles. However, designing new proteins that are functional remains challenging, in part because designing binding interactions requires simultaneous optimization of protein sequence and protein-ligand conformation. Polizzi and DeGrado designed proteins from scratch that bind a small-molecule drug (see the Perspective by Peacock). They introduced a new structural element called a van der Mer (vdM), which tracks the orientation of a chemical group relative to the backbone of a contacting residue. Assuming proteins bind ligands using interactions similar to intraprotein packing, they determined statistically preferred vdMs from a large set of structures in the Protein Data Bank. By including weighted vdMs in their computations, they designed two of six de novo proteins that bind the drug apixaban. A drug-protein x-ray crystal structure confirmed the designed model.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1227" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abb8330">1227</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1166" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abd4791">1166</jats:related-article> </jats:p>

<jats:title>Ripping up a circumstellar disk</jats:title> <jats:p> During the process of star formation, a disk of gas and dust forms around the young star, controlling the accretion of more material. Once the star has formed, any leftover material in this circumstellar disk can form planets. If a binary or triple star forms at the center of the disk, theoretical models predict that tidal torques caused by their orbits can rip the disk apart, in a process known as disk tearing. Kraus <jats:italic>et al.</jats:italic> observed the nearby young triple-star system GW Orionis with multiple near-infrared and submillimeter telescopes, using the techniques of interferometry and polarimetry. They found evidence for multiple rings with different orientations and warping of part of the disk, both produced by disk tearing. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1233" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba4633">1233</jats:related-article> </jats:p>

<jats:title>A very precise ratio</jats:title> <jats:p> The value of the ratio of the masses of the proton and the electron has a bearing on the values of other physical constants. This ratio is known to a very high precision. Patra <jats:italic>et al.</jats:italic> improved this precision even further by measuring particular frequencies in the rovibrational spectrum of the hydrogen deuteride molecular ion (HD <jats:sup>+</jats:sup> ) (see the Perspective by Hori). To reach this high precision, the researchers placed the HD <jats:sup>+</jats:sup> molecules in an ion trap and surrounded them by beryllium ions. The cold beryllium ions then helped cool the HD <jats:sup>+</jats:sup> molecules, making the HD <jats:sup>+</jats:sup> spectral lines narrow enough that the proton-electron mass ratio could be extracted by comparison with theoretical predictions. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1238" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba0453">1238</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1160" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abb9186">1160</jats:related-article> </jats:p>

<jats:title>Accounting for heat burdens</jats:title> <jats:p> As climate warming becomes more and more apparent and influential, there is an increasing desire to predict its long-term impacts on species. Classically, this has been done by extrapolating lethal limits based on those observed in the laboratory. In the real world, however, organisms do not experience a single high temperature that then returns to a comfortable temperature, but rather a series of high temperatures during the hot season. Rezende <jats:italic>et al.</jats:italic> accounted for these accumulative effects in a dynamic model that accurately predicted empirical patterns in wild fruit fly populations, showing that cumulative effects of warming temperatures can be included in future estimates (see the Perspective by Huey and Kearney). </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1242" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.aba9287">1242</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1163" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abe0320">1163</jats:related-article> </jats:p>

<jats:title>Terrestrial biogeochemistry of silicon</jats:title> <jats:p> Silicon is an important element in plant tissues and contributes to structural defenses against herbivores and other stresses. However, the terrestrial biogeochemical cycling of silicon is poorly understood, particularly the relative importance of geochemical and biological mechanisms in its regulation. de Tombeur <jats:italic>et al.</jats:italic> studied this question in 2-million-year chronosequences of soil and vegetation in Western Australia. Sites became progressively more weathered and infertile as they aged, indicating that the silicon cycle shifts from geochemical to biological control as the ecosystem develops (see the Perspective by Carey). They found that foliar silicon concentrations increase continuously during ecosystem development, even though rock-derived silicon is depleted in the older soils. By contrast, other major rock-derived nutrients showed decreasing concentrations in plants. Hence, biological silicon cycling allows plants to maintain concentrations even under conditions of extreme soil infertility. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1245" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abc0393">1245</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1161" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abd9425">1161</jats:related-article> </jats:p>

<jats:title>A viral block on host protein synthesis</jats:title> <jats:p> As the coronavirus disease 2019 (COVID-19) pandemic continues to cause devastation, scientists race to increase their understanding of the disease-causing severe acute respiratory syndrome coronavirus 2. Once inside host cells, not only does the virus hijack the cells' translational machinery to make viral proteins, but the virulence factor nonstructural protein 1 (Nsp1) also shuts down translation of host messenger RNA. Thoms <jats:italic>et al.</jats:italic> determined a 2.6-angstrom resolution cryo–electron microscopy structure of a reconstituted complex of Nsp1 bound to the human 40 <jats:italic>S</jats:italic> ribosomal subunit and showed that Nsp1 blocks the messenger RNA entry tunnel. A structural inventory of native Nsp1-ribosome complexes from human cells confirms this mechanism. Cellular studies show that the translational shutdown almost completely inhibits the innate immune response. The binding pocket on the ribosome may be a target for drugs to treat COVID-19. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1249" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abc8665">1249</jats:related-article> </jats:p>

<jats:title>The spread of SARS-CoV-2 in Brazil</jats:title> <jats:p> Brazil has been hard-hit by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Candido <jats:italic>et al.</jats:italic> combined genomic and epidemiological analyses to investigate the impact of nonpharmaceutical interventions (NPIs) in the country. By setting up a network of genomic laboratories using harmonized protocols, the researchers found a 29% positive rate for SARS-CoV-2 among collected samples. More than 100 international introductions of SARS-CoV-2 into Brazil were identified, including three clades introduced from Europe that were already well established before the implementation of NPIs and travel bans. The virus spread from urban centers to the rest of the country, along with a 25% increase in the average distance traveled by air passengers before travel bans, despite an overall drop in short-haul travel. Unfortunately, the evidence confirms that current interventions remain insufficient to keep virus transmission under control in Brazil. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6508" page="1255" related-article-type="in-this-issue" vol="369" xlink:href="10.1126/science.abd2161">1255</jats:related-article> </jats:p>