Catálogo de publicaciones - revistas

<jats:title>Watching it all fall apart</jats:title> <jats:p> The control of the shape and size of metal nanoparticles can be very sensitive to the growth conditions of the particles. Ye <jats:italic>et al.</jats:italic> studied the reverse process: They tracked the dissolution of gold nanoparticles in a redox environment inside a liquid cell within an electron microscope, controlling the particle dissolution with the electron beam. Tracking short-lived particle shapes revealed structures of greater or lesser stability. The findings suggest kinetic routes to particle sizes and shapes that would otherwise be difficult to generate. </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="6314" page="874" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah4434">874</jats:related-article> </jats:p>

<jats:title>Drilling into Chicxulub's formation</jats:title> <jats:p> The Chicxulub impact crater, known for its link to the demise of the dinosaurs, also provides an opportunity to study rocks from a large impact structure. Large impact craters have “peak rings” that define a complex crater morphology. Morgan <jats:italic>et al.</jats:italic> looked at rocks from a drilling expedition through the peak rings of the Chicxulub impact crater (see the Perspective by Barton). The drill cores have features consistent with a model that postulates that a single over-heightened central peak collapsed into the multiple-peak-ring structure. The validity of this model has implications for far-ranging subjects, from how giant impacts alter the climate on Earth to the morphology of crater-dominated planetary surfaces. </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="6314" page="878" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah6561">878</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="836" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aak9802">836</jats:related-article> </jats:p>

<jats:title>Directing traffic with patterns</jats:title> <jats:p> Biological entities, such as bacteria, may direct their motion in response to their environment, but this usually does not lead to large-scale patterns or collective behavior. Peng <jats:italic>et al.</jats:italic> found that the orientational ordering of a liquid crystal could direct the flow of self-propelling bacteria, which in turn influenced the patterning of the liquid crystal molecules. Patterns on a substrate caused surface anchoring of the liquid crystals that transmitted to the ordering of the bacteria, thus imparting control on what would otherwise be chaotic out-of-equilibrium behavior. </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="6314" page="882" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah6936">882</jats:related-article> </jats:p>

<jats:title>Combining heat and light responses</jats:title> <jats:p> Plants integrate a variety of environmental signals to regulate growth patterns. Legris <jats:italic>et al.</jats:italic> and Jung <jats:italic>et al.</jats:italic> analyzed how the quality of light is interpreted through ambient temperature to regulate transcription and growth (see the Perspective by Halliday and Davis). The phytochromes responsible for reading the ratio of red to far-red light were also responsive to the small shifts in temperature that occur when dusk falls or when shade from neighboring plants cools the soil. </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="6314" page="897" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf5656">897</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="886" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf6005">886</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="832" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaj1918">832</jats:related-article> </jats:p>

<jats:title>Metabolite channeling by a dynamic metabolon</jats:title> <jats:p> The specialized metabolite dhurrin breaks down into cyanide when plant cell walls have been chewed, deterring insect pests. Laursen <jats:italic>et al.</jats:italic> found that the enzymes that synthesize dhurrin in sorghum assemble as a metabolon in lipid membranes (see the Perspective by Dsatmaichi and Facchini). The dynamic nature of metabolon assembly and disassembly provides dhurrin on an as-needed basis. Membrane-anchored cytochrome P450s cooperated with a soluble glucosyltransferase to channel intermediates toward efficient dhurrin production. </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="6314" page="890" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aag2347">890</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="829" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal2948">829</jats:related-article> </jats:p>

<jats:title>Sacral neurons reassigned</jats:title> <jats:p> The autonomic nervous system regulates the function of internal organs such as the gut. The parasympathetic and sympathetic arms of this system tend to operate antagonistically. Espinosa-Medina <jats:italic>et al.</jats:italic> used anatomical and molecular analyses to reevaluate the assignment of neurons in the sacral autonomic nervous system (see the Perspective by Adameyko). Previously categorized as parasympathetic, these neurons are now identified as sympathetic. The results resolve a persistent confusion about how the two systems developed and open the avenue to more predictable outcomes in developing treatments targeted to the pelvic autonomic nervous 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="6314" page="893" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5454">893</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="833" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal2810">833</jats:related-article> </jats:p>

<jats:title>Combining heat and light responses</jats:title> <jats:p> Plants integrate a variety of environmental signals to regulate growth patterns. Legris <jats:italic>et al.</jats:italic> and Jung <jats:italic>et al.</jats:italic> analyzed how the quality of light is interpreted through ambient temperature to regulate transcription and growth (see the Perspective by Halliday and Davis). The phytochromes responsible for reading the ratio of red to far-red light were also responsive to the small shifts in temperature that occur when dusk falls or when shade from neighboring plants cools the soil. </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="6314" page="897" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf5656">897</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="886" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf6005">886</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="832" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaj1918">832</jats:related-article> </jats:p>

<jats:title>Optimizing designer metabolisms in vitro</jats:title> <jats:p> Biological carbon fixation requires several enzymes to turn CO <jats:sub>2</jats:sub> into biomass. Although this pathway evolved in plants, algae, and microorganisms over billions of years, many reactions and enzymes could aid in the production of desired chemical products instead of biomass. Schwander <jats:italic>et al.</jats:italic> constructed an optimized synthetic carbon fixation pathway in vitro by using 17 enzymes—including three engineered enzymes—from nine different organisms across all three domains of life (see the Perspective by Gong and Li). The pathway is up to five times more efficient than the in vivo rates of the most common natural carbon fixation pathway. Further optimization of this and other metabolic pathways by using similar approaches may lead to a host of biotechnological applications. </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="6314" page="900" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5237">900</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6314" page="830" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal1559">830</jats:related-article> </jats:p>

<jats:title>Tau phosphorylation—not all bad</jats:title> <jats:p> Alzheimer's disease presents with amyloid-β (Aβ) plaques and tau tangles. The prevailing idea in the field is that Aβ induces phosphorylation of tau, which in turn mediates neuronal dysfunction. Working in Alzheimer's disease mouse models, Ittner <jats:italic>et al.</jats:italic> found evidence for a protective role of tau in early Alzheimer's disease. This protection involves specific tau phosphorylation at threonine 205 at the postsynapse. A protective role of phosphorylated tau in disease challenges the dogma that tau phosphorylation only mediates toxic processes. </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="6314" page="904" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah6205">904</jats:related-article> </jats:p>

<jats:title>Combating parasitic DNA by methylation</jats:title> <jats:p> DNA methylation plays an important role in repressing the expression of “parasitic” DNAs, such as transposable elements, which have invaded our genomes. Mammals have three DNA methyltransferase enzymes. Barau <jats:italic>et al.</jats:italic> discovered a fourth DNA methyltransferase enzyme in mice. The enzyme DNMT3C is a duplication of DNMT3B and is found in male germ cells. There it targets evolutionarily young transposons, of which there is a heavy burden in the mouse genome. DNMT3C methylates and silences the young transposons, preserving male fertility. </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="6314" page="909" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5143">909</jats:related-article> </jats:p>