Catálogo de publicaciones - revistas

<jats:title>Miniproteins against SARS-CoV-2</jats:title> <jats:p> Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is decorated with spikes, and viral entry into cells is initiated when these spikes bind to the host angiotensin-converting enzyme 2 (ACE2) receptor. Many monoclonal antibody therapies in development target the spike proteins. Cao <jats:italic>et al.</jats:italic> designed small, stable proteins that bind tightly to the spike and block it from binding to ACE2. The best designs bind with very high affinity and prevent SARS-CoV-2 infection of mammalian Vero E6 cells. Cryo–electron microscopy shows that the structures of the two most potent inhibitors are nearly identical to the computational models. Unlike antibodies, the miniproteins do not require expression in mammalian cells, and their small size and high stability may allow formulation for direct delivery to the nasal or respiratory system. </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="6515" page="426" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd9909">426</jats:related-article> </jats:p>

<jats:title>Spinal circuit development</jats:title> <jats:p> Motor neuron circuits in the zebrafish spinal cord support both the rapid evasion response and the leisurely swimming response. Kishore <jats:italic>et al.</jats:italic> now follow the development of inhibitory interneurons as these circuits are assembled in the larva. Interneurons generated early in development drive different sorts of circuits and synapse onto different subcellular sections of the motor neurons than interneurons generated later in development. Thus, both rapid evasion and slower swimming are supported by the same cellular components assembled in different ways. The authors suggest that development follows an opportunistic rule in which interneurons synapse onto what is available to them at that moment in development. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6515" page="431" related-article-type="in-this-issue" vol="370">431</jats:related-article> </jats:p>

<jats:title>A new future for polyethylene</jats:title> <jats:p> Most current plastic recycling involves chopping up the waste and repurposing it in materials with less stringent engineering requirements than the original application. Chemical decomposition at the molecular level could, in principle, lead to higher-value products. However, the carbon-carbon bonds in polyethylene, the most common plastic, tend to resist such approaches without exposure to high-pressure hydrogen. F. Zhang <jats:italic>et al.</jats:italic> now report that a platinum/alumina catalyst can transform waste polyethylene directly into long-chain alkylbenzenes, a feedstock for detergent manufacture, with no need for external hydrogen (see the Perspective by Weckhuysen). </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="6515" page="437" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abc5441">437</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6515" page="400" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abe3873">400</jats:related-article> </jats:p>

<jats:title>Using curves to make twists</jats:title> <jats:p> The growth of layered materials on flat substrates usually occurs in stacked layers, although defects or a lattice mismatch can induce strains that distort the shape of subsequent layers. However, these effects are usually small and can be uncontrolled. Zhao <jats:italic>et al.</jats:italic> now demonstrate the possibility of synthesizing multilayers of two-dimensional materials with certain twists between the layers induced by the presence of screw dislocations in combination with curved substrate surfaces. Different twist angles are achieved by varying the amount of nonplanarity and the character (conical or hyperbolic) of the surface. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6515" page="442" related-article-type="in-this-issue" vol="370">442</jats:related-article> </jats:p>

<jats:title>The iron did it</jats:title> <jats:p> What factors controlled the accumulation of atmospheric oxygen gas (O <jats:sub>2</jats:sub> ) early in the history of Earth? Heard <jats:italic>et al.</jats:italic> used high-precision iron isotopic measurements of Archean-Paleoproterozoic sediments, with ages between 3.8 billion and 2.3 billion years ago, and laboratory data about synthetic pyrites to show that pyrite, or iron sulfide, burial could have resulted in net O <jats:sub>2</jats:sub> export. These reactions therefore may have contributed to early episodes of transient oxygenation before the Great Oxidation Event that began about 2.4 billion years ago. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6515" page="446" related-article-type="in-this-issue" vol="370">446</jats:related-article> </jats:p>

<jats:title>Saving a host cell from itself</jats:title> <jats:p> A fundamental mammalian defense mechanism against pathogens and damaged cellular DNA is to recognize DNA fragments in the cytosol and trigger an inflammatory response. The cyclic guanosine monophosphate–adenosine monophosphate synthase (cGAS) that recognizes cytosolic DNA is also found in the nucleus, but here its activity is suppressed by tethering to chromatin. Two papers now report cryo–electron microscopy structures of cGAS bound to the nucleosome core particle (NCP). Kujirai <jats:italic>et al.</jats:italic> observed a structure with two cGAS molecules bridging two NCPs, whereas Boyer <jats:italic>et al.</jats:italic> observed cGAS bound to a single nucleosome. Together, these structures show how cGAS is prevented from autoreactivity toward host DNA. </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="6515" page="455" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd0237">455</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6515" page="450" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd0609">450</jats:related-article> </jats:p>

<jats:title>Saving a host cell from itself</jats:title> <jats:p> A fundamental mammalian defense mechanism against pathogens and damaged cellular DNA is to recognize DNA fragments in the cytosol and trigger an inflammatory response. The cyclic guanosine monophosphate–adenosine monophosphate synthase (cGAS) that recognizes cytosolic DNA is also found in the nucleus, but here its activity is suppressed by tethering to chromatin. Two papers now report cryo–electron microscopy structures of cGAS bound to the nucleosome core particle (NCP). Kujirai <jats:italic>et al.</jats:italic> observed a structure with two cGAS molecules bridging two NCPs, whereas Boyer <jats:italic>et al.</jats:italic> observed cGAS bound to a single nucleosome. Together, these structures show how cGAS is prevented from autoreactivity toward host DNA. </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="6515" page="455" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd0237">455</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6515" page="450" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd0609">450</jats:related-article> </jats:p>

<jats:title>Metasurface-based microdisplays</jats:title> <jats:p> Organic light-emitting diodes (OLEDs) have found wide application in high-resolution, large-area televisions and the handheld displays of smartphones and tablets. With the screen located some distance from the eye, the typical number of pixels per inch is in the region of hundreds. For near-eye microdisplays—for example, in virtual and augmented reality applications—the required pixel density runs to several thousand pixels per inch and cannot be met by present display technologies. Joo <jats:italic>et al.</jats:italic> developed a full-color, high-brightness OLED design based on an engineered metasurface as a tunable back-reflector. An ultrahigh density of 10,000 pixels per inch readily meets the requirements for the next-generation microdisplays that can be fabricated on glasses or contact lenses. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6515" page="459" related-article-type="in-this-issue" vol="370">459</jats:related-article> </jats:p>

<jats:title>Origins of the pituitary gland</jats:title> <jats:p> Placodes are specializations of the head ectoderm that are considered the source of many vertebrate novelties, including the nose, lens, ear, and hormone-producing portion of the pituitary. However, the presence of a pituitary-like structure in nonvertebrate chordates, derived instead from the endoderm, had suggested that the pituitary may predate placodes. Fabian <jats:italic>et al.</jats:italic> performed lineage tracing, time-lapse imaging, and single-cell messenger RNA sequencing to show that both endodermal and ectodermal cells can generate hormone-producing cells of the zebrafish pituitary. These experiments support that the vertebrate pituitary arises through interactions of an ancestral endodermal protopituitary with newly evolved placodal ectoderm. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6515" page="463" related-article-type="in-this-issue" vol="370">463</jats:related-article> </jats:p>