Catálogo de publicaciones - revistas

<jats:title>Watching graphene grow</jats:title> <jats:p> The growth of graphene on metal surfaces can be catalyzed by mobile surface metal atoms. Patera <jats:italic>et al.</jats:italic> used a high-speed scanning tunneling microscope to image the growth of graphene islands on a nickel surface. High temperatures caused carbon to diffuse to the surface, where mobile nickel atoms catalyzed graphene growth on the edges of islands. Molecular dynamics and density functional theory calculations provide mechanistic insights into the reaction steps. </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="6381" page="1243" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aan8782">1243</jats:related-article> </jats:p>

<jats:title>A quick freeze shows an enzyme's secrets</jats:title><jats:p>Organic radicals are chemically useful in enzymatic reactions but are often hard to observe, owing to their short lifetimes. Dong<jats:italic>et al.</jats:italic>used rapid freeze-quench methods to trap two intermediates formed by a noncanonical radical S-adenosylmethionine (SAM) enzyme: a fragmented SAM molecule bound to the iron-sulfur cluster through an iron-carbon bond and a product-like radical. The structure of the SAM-bound enzyme reveals a noncolinear arrangement of carbon, sulfur, and iron atoms. The arrangement of bonds suggests that the organometallic intermediate may be created through a two-electron nucleophilic mechanism. A subsequent radical intermediate is formed on the protein substrate and resolves by oxidation to form the amino acid product diphthamide.</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="6381" page="1247" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao6595">1247</jats:related-article></jats:p>

<jats:title>Injection depth matters for induced earthquakes</jats:title> <jats:p> Wastewater injection has induced earthquakes in Oklahoma, but the relative importance of operational and geologic parameters in triggering such earthquakes is unclear. Hincks <jats:italic>et al.</jats:italic> developed an advanced Bayesian network to determine the interplay between these parameters in Oklahoma. The injection depth above the crystalline basement was the most important parameter when considering the potential for release of seismic energy. This modeling strategy may provide a way to improve forecasts of the impact of proposed regulatory changes on induced seismicity. </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="6381" page="1251" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aap7911">1251</jats:related-article> </jats:p>

<jats:title>Healthy fisheries can reduce bycatch</jats:title> <jats:p> Bycatch of marine mammals, turtles, and birds during commercial fishing is a considerable threat. Activities intended to reduce bycatch are often thought to conflict with commercial fishing. However, Burgess <jats:italic>et al.</jats:italic> show that in the majority of cases, managing fishery stocks to best promote long-term sustainability would also reduce bycatch. Rebuilding fish stocks will naturally promote lower bycatch, and these factors together will facilitate sustainable profit generation from fish harvest. </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="6381" page="1255" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao4248">1255</jats:related-article> </jats:p>

<jats:title> Sexual development in <jats:italic>Plasmodium</jats:italic> </jats:title> <jats:p> Malaria-causing parasites ( <jats:italic>Plasmodium</jats:italic> ) have complex life histories in the tissues of humans. For the most part, the parasites focus their efforts on replication within the human host cells. However, occasionally, some replicating cells release gametes into the bloodstream, which are picked up by biting mosquitoes. Filarsky <jats:italic>et al.</jats:italic> discovered that the <jats:italic>Plasmodium</jats:italic> parasite keeps the production of gametes under tight epigenetic control using heterochromatin protein 1 (HP1). <jats:italic>Plasmodium</jats:italic> gametocytogenesis is initiated when HP1 is evicted from upstream of gamete-specific genes by gametocyte development 1 (GDV1) protein. GDV1 is in turn regulated by its antisense RNA. What triggers GDV1 expression remains unclear. Elucidating this pathway could provide a target for interrupting malaria transmission. </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="6381" page="1259" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aan6042">1259</jats:related-article> </jats:p>

<jats:title>The infant as philosopher</jats:title> <jats:p> Visual behaviors, such as a shift in one's gaze or a prolonged stare, can be diagnostic of internal thoughts. Cesana-Arlotti <jats:italic>et al.</jats:italic> used these measures to demonstrate that preverbal infants can formulate a logical structure called a disjunctive syllogism (see the Perspective by Halberda). That is, if A or B is true, and A is false, then B must be true. Presenting infants with scenes where the outcome revealed B to be false evoked looks of surprise. </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="6381" page="1263" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao3539">1263</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6381" page="1214" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aas9183">1214</jats:related-article> </jats:p>

<jats:title>Stream physics set the limits</jats:title> <jats:p> A combination of physical transport processes and biologically mediated reactions in streams and their sediments removes dissolved inorganic nitrogen (DIN) from the water. Although stream chemistry and biology have been considered the dominant controls on how quickly DIN is removed, Grant <jats:italic>et al.</jats:italic> show that physics is what sets the limits on removal rates of nitrate (a component of DIN). Residence time in the hyporheic zone (the region below the sediment surface where groundwater and surface water mix) determines the maximum rate at which nitrate can be removed from stream water. Nevertheless, at local scales, chemistry and biology modify how closely to that maximum rate removal occurs. </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="6381" page="1266" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aap8074">1266</jats:related-article> </jats:p>

<jats:title>Call to action</jats:title> <jats:p> The developing brain initially makes more synapses than it needs. With further development, excess synapses are pruned away, leaving mature circuits. Synapses can be eliminated by microglia, which engulf and destroy them. Vainchtein <jats:italic>et al.</jats:italic> found that the microglia are called into action by astrocytes, supportive cells on which neurons rely. Astrocytes near a redundant synapse release the cytokine interleukin-33 (IL-33), which recruits microglia to the site. In mice, disruptions in this process, as caused by deficiency in IL-33, led to too many excitatory synapses and overactive brain circuitry. </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="6381" page="1269" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aal3589">1269</jats:related-article> </jats:p>

<jats:title>Chromosome dynamics and cellular clocks</jats:title> <jats:p> Many genes undergo daily or circadian changes in their rate of transcription. Kim <jats:italic>et al.</jats:italic> explored the mechanism by which the circadian clock is linked to chromosome dynamics (see the Perspective by Diettrich Mallet de Lima and Göndör). They used a chromosome conformation capture technique (Hi-C) to identify the interactions of adjacent DNA fragments and determine how DNA looping that altered such interactions changed over daily cycles. The repressive transcription factor Rev-erbα, which functions as part of the mammalian clock mechanism, appears to bind to chromatin and recruit a protein complex that evicts other proteins that enhance looping, thus favoring enhancer-promoter interactions. </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="6381" page="1274" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao6891">1274</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6381" page="1212" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aat0934">1212</jats:related-article> </jats:p>

<jats:title>Lysosomes keep neuronal stem cells young</jats:title> <jats:p> An important consequence of aging is loss of regenerative capacity in stem cells, particularly those of the nervous system. Leeman <jats:italic>et al.</jats:italic> isolated quiescent and activated stem cells from mice and compared their transcriptomes. The findings emphasize the role of large lysosomes in quiescent neuronal stem cells in which aggregated proteins accumulate. Treatments that stimulated lysosomal function allowed aged quiescent stem cells to clear protein aggregates and restored the cells' ability to be activated. Such restoration of stem cell function might alleviate compromised proteostasis in aging. </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="6381" page="1277" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aag3048">1277</jats:related-article> </jats:p>