Catálogo de publicaciones - revistas

<jats:title>Radioprotective bacteria</jats:title> <jats:p> A common symptom of radiation treatment for cancer is gastrointestinal disruption. The damage caused can become so severe and debilitating that it interrupts treatment. Guo <jats:italic>et al.</jats:italic> noticed that mice surviving experimental radiation exposure had distinctive taxonomic representation in their gut microbiota. A similar correlation was also observed in a small group of human subjects. Further experiments in mice revealed that some strains of bacteria produced high levels of short-chain fatty acids, which seemed to be dampening inflammatory responses and alleviating the damage caused by reactive oxygen species released by the radiation. A metabolomics analysis also implicated a role for tryptophan metabolic pathways in radiation survivorship. </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.aay9097">eaay9097</jats:related-article> </jats:p>

<jats:title>Secrets of a proton pumping machine</jats:title> <jats:p> Mitochondrial complex I serves as a primary entry point for electrons from the tricarboxylic acid cycle into the mitochondrial electron transport chain. This massive, membrane-embedded protein complex must couple quinone reduction to conformational changes across more than 150 angstroms within four separate proton pumps. Kampjut <jats:italic>et al.</jats:italic> determined five structures of complex I in states along the catalytic cycle, a deactive conformation, and one with the inhibitor rotenone bound. The resolution of some structures was sufficient to see water molecules and to trace putative paths for proton transfer within the proton-pumping membrane domain. The structures add valuable details that provide a basis for generating mechanistic hypotheses for this crucial complex. </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.abc4209">eabc4209</jats:related-article> </jats:p>

<jats:title>Structural secrets of hybrid perovskites</jats:title> <jats:p> The optoelectronic and photovoltaic applications of polycrystalline hybrid metal halide perovskite films are notable because grain boundaries in most materials cause scattering of charge carriers that decreases performance. Electron microscopy studies of these materials have been hindered by their rapid structural degradation under intense electron beams. Rothmann <jats:italic>et al.</jats:italic> now present an atomic crystallographic structure of formamidinium lead triiodide (FAPbI <jats:sub>3</jats:sub> ) polycrystalline thin films obtained by low-electron-dose scanning transmission electron microscopy with advanced image processing. The crystal structure sustains substoichiometry in the A-site cation, has a nearly perfect crystallographic alignment between PbI <jats:sub>2</jats:sub> impurity phases and the FAPbI <jats:sub>3</jats:sub> perovskite, and has atomically clean grain boundaries between polycrystalline domains. These features help to explain the films' surprising regenerative ability, their benign grain boundaries where strain and dislocations appear mostly absent, and why excess lead-iodide precursor can be counterintuitively beneficial. </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.abb5940">eabb5940</jats:related-article> </jats:p>