Catálogo de publicaciones - revistas

<jats:title>Ocean winds blowing harder</jats:title> <jats:p>Two frequently asked questions about how climate warming will affect the environment are whether windiness might change and what effects that might have on ocean waves. Young and Ribal analyzed global satellite data over the period from 1985 to 2018 to determine if there are any trends in oceanic wind speed and wave height. They found small increases in both quantities, with the strongest increases in extreme conditions and in the Southern Ocean. These findings are important for understanding air-sea exchange of energy and carbon dioxide and for projecting sea levels during storms.</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="6440" page="548" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav9527">548</jats:related-article> </jats:p>

<jats:title>Choosing a partner</jats:title> <jats:p> G protein–coupled receptors (GPCRs) bind ligands outside the cell and trigger events inside the cell by selectively binding and activating specific G proteins. The selectivity occurs even among highly related GPCRs. For example, five subtypes of muscarinic acetylcholine receptors (M1R to M5R) play different roles in the nervous system by binding to different G proteins. Maeda <jats:italic>et al.</jats:italic> determined cryo–electron microscopy structures of M1R and M2R bound to their respective G proteins. A side-by-side comparison provided a molecular understanding of G protein–coupling selectivity. </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="6440" page="552" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw5188">552</jats:related-article> </jats:p>

<jats:title>Sparing T cells from inhibition</jats:title> <jats:p> Programmed cell death 1 (PD-1) is an inhibitory receptor that normally keeps T cell immune responses in check. Immunotherapy targeting PD-1 has proven successful for certain types of cancer, but it remains unclear how PD-1 is regulated. Sugiura <jats:italic>et al.</jats:italic> found that a costimulatory molecule, CD80, can restrict PD-1 function during the activation of T lymphocytes. Binding of CD80 to the PD-1 ligand PD-L1 in cis on primary activated dendritic cells interfered with the ability of PD-L1 to access PD-1 on T cells, which would otherwise have inhibited T cell activation. Functional insights into PD-L1–CD80 interactions may explain the outcomes of anti–PD-1 and anti–PD-L1 cancer therapy. </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="6440" page="558" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav7062">558</jats:related-article> </jats:p>

<jats:title>How many metals to oxidize methane?</jats:title> <jats:p> Methane is an important fuel, but there are few direct transformations to partially oxidized products. Bacteria use metalloenzymes to catalyze methane oxidation to methanol, a reaction of industrial interest. Understanding the metal sites that enable this reaction may inspire new biomimetic catalysts. Ross <jats:italic>et al.</jats:italic> used spectroscopic measurements to assign two monocopper sites in the enzyme particulate methane monooxygenase. These results differ in part from previous proposals for the location and nuclearity of the metal sites and will prompt rethinking about how this metalloenzyme catalyzes methane oxidation. </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="6440" page="566" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav2572">566</jats:related-article> </jats:p>

<jats:title>Ionic floating-gate memories</jats:title> <jats:p> Digital implementations of artificial neural networks perform many tasks, such as image recognition and language processing, but are too energy intensive for many applications. Analog circuits that use large crossbar arrays of synaptic memory elements represent a low-power alternative, but most devices cannot update the synaptic weights uniformly or scale to large array sizes. Fuller <jats:italic>et al.</jats:italic> developed an integrated device, ionic floating-gate memory, that has the gate terminal of a redox transistor electrically connected to a diffusive memristor. This low-power device enabled linear and symmetric weight updates in parallel over an entire crossbar array at megahertz rates over 10 <jats:sup>9</jats:sup> write-read cycles. </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="6440" page="570" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw5581">570</jats:related-article> </jats:p>

<jats:title>The right bond in the right place</jats:title> <jats:p> Enzymes excel at specificity because of their constrained active sites. With appropriate evolutionary pressure, they can be made to differentiate between similar substrates or between positions on a single substrate. Cho <jats:italic>et al.</jats:italic> used directed evolution to generate cytochrome P450 variants that target different C–H bonds in substrates, forming lactam rings of varying size (see the Perspective by Hepworth and Flitsch). The enzyme directs amidation to the desired position and simultaneously prevents other side reactions. </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="6440" page="575" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw9068">575</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6440" page="529" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax3335">529</jats:related-article> </jats:p>

<jats:title>Afferents modulate newborn neurons</jats:title> <jats:p> What is the role of adult neurogenesis in learning, memory, and mood? Luna <jats:italic>et al.</jats:italic> found that adult-born neurons either inhibited or excited the dentate gyrus, depending on whether synaptic inputs originated from the lateral or the medial entorhinal cortex (see the Perspective by Llorens-Martín). These opposing mechanisms were driven by extrasynaptic transmission from adult-born neurons directly onto mature granule cells via metabotropic glutamate receptors or <jats:italic>N</jats:italic> -methyl- <jats:sc>D</jats:sc> -aspartate receptors, respectively. The balance between these mechanisms could explain the differences in dentate gyrus activity during two versions of an active place-avoidance task. The action of adult-born neurons thus depended entirely on the demands of the environment, which can be defined by the activity of cortical and subcortical regions sending inputs to the dentate gyrus. </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="6440" page="578" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aat8789">578</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6440" page="530" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax5186">530</jats:related-article> </jats:p>