Catálogo de publicaciones - revistas

<jats:title>Applying pressure to plate tectonics</jats:title> <jats:p> The full range of deformation behavior of subduction zone faults that are responsible for great earthquakes and tsunamis is now clearer. Wallace <jats:italic>et al.</jats:italic> observed the heave of the ocean floor near the Hikurangi trench, off the east coast of New Zealand, with a network of absolute pressure gauges (see the Perspective by Tréhu). The gauges sit on the ocean floor and detect changes in pressure generated from slow-slip deformation events. Detailed geodetic observation of deformation events will finally clarify the role that such aseismic events play at major plate boundaries. </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="6286" page="701" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf2349">701</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6286" page="654" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf6534">654</jats:related-article> </jats:p>

<jats:title>An isotope record of magnetic bacteria</jats:title> <jats:p> Microorganisms have shaped Earth's oceans and atmosphere over billions of years. Ancient microbes left very little direct morphological evidence of their existence in the rock record, thereby requiring geochemical clues for evidence of their activity. Amor <jats:italic>et al.</jats:italic> show that magnetotactic bacteria impart a distinct isotopic signature to their internal iron nanoparticles. Cultures of a modern magnetic bacterium fractionated <jats:sup>57</jats:sup> Fe isotopes independent of their mass, in contrast to fractionation patterns often observed for other isotopes. Because this signature is not produced abiotically or by other iron-metabolizing bacteria, it could serve as a reliable biomarker of this ancient magnetic microbial lifestyle. </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="6286" page="705" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad7632">705</jats:related-article> </jats:p>

<jats:title>Narrowing of the life expectancy gap</jats:title> <jats:p>In the United States, the rich can expect to enjoy better health and a longer life than the poor. Despite policies directed at improving the health of both the young and the poor, there is little evidence that this relationship has changed. Currie and Schwandt looked specifically at the life expectancy of present-day children and young adults, finding that mortality inequality has in fact declined over the past 25 years (see the Perspective by Bailey and Timpe).</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="6286" page="708" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf1437">708</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6286" page="661" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf7270">661</jats:related-article> </jats:p>

<jats:title>Too much cleaning up</jats:title> <jats:p> The complement system and microglia seek out and destroy unwanted cellular debris for the peripheral immune system as well as excess synapses in the developing brain. Hong <jats:italic>et al.</jats:italic> now show how the system may go haywire in adults early in the progression toward Alzheimer's disease (AD). Aberrant synapse loss is an early feature of Alzheimer's and correlates with cognitive decline. In mice susceptible to AD, complement was associated with synapses, and microglial function was required for synapse loss. The authors speculate that aberrant activation of this “trash disposal” system underlies AD pathology. </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="6286" page="712" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad8373">712</jats:related-article> </jats:p>

<jats:title>Deciphering the histone code</jats:title> <jats:p> Regulatory information is stored both in DNA sequences and in the chromatin proteins that package the genome. The covalent modification of histones plays a critical role in signaling whether a gene or genomic region should be active or inactive. Shema <jats:italic>et al.</jats:italic> used high-throughput single-molecule imaging to reveal the different combinations of modifications on millions of individual nucleosomes. Single-molecule DNA sequencing determined the exact location of these modified nucleosomes in the genome. </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="6286" page="717" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad7701">717</jats:related-article> </jats:p>

<jats:title>Stay on the right track</jats:title> <jats:p>Cilia contain a well-ordered array of microtubule doublets along their length. A longstanding question in cilium structure and function is why the microtubule arrangement in cilia is so complex. Stepanek and Pigino developed a time-resolved correlative fluorescence and three-dimensional electron microscopy method to show that the doublets provide directionality to intraflagellar transport. One microtubule in the pair moves cargoes up to the ciliary tip. Meanwhile, the other microtubule moves cargoes back to the cell body. These results explain why the axoneme is built out of microtubule doublets and suggest a mechanistic picture of how the logistics of bidirectional intraflagellar transport are regulated.</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="6286" page="721" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aaf4594">721</jats:related-article> </jats:p>

<jats:title>Visualizing a response to light</jats:title> <jats:p> Many biological processes depend on detecting and responding to light. The response is often mediated by a structural change in a protein that begins when absorption of a photon causes isomerization of a chromophore bound to the protein. Pande <jats:italic>et al.</jats:italic> used x-ray pulses emitted by a free electron laser source to conduct time-resolved serial femtosecond crystallography in the time range of 100 fs to 3 ms. This allowed for the real-time tracking of the trans-cis isomerization of the chromophore in photoactive yellow protein and the associated structural changes in the protein. </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="6286" page="725" related-article-type="in-this-issue" vol="352" xlink:href="10.1126/science.aad5081">725</jats:related-article> </jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>

<jats:p> The CRISPR/Cas9 system allows for unprecedented ease and control when editing the genome. Its potential impact on drug discovery is vast, including enabling gene and cell replacement therapies, identifying novel drug targets through functional genomic screens, and simplifying the production of disease models using permanent knockouts for validating therapy targets and testing drug efficacy. But in practical terms, how is CRISPR/Cas9 currently being applied, and where might the future challenges and pitfalls be? Furthermore, how do assays based on the new CRISPR/Cas9 technology compare with current screening methodologies, particularly those using small interfering RNA (siRNA)? <jats:list list-type="bullet"> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://webinar.sciencemag.org/webinar/archive/crisprcas9-drug-discovery">View the Webinar</jats:ext-link> </jats:p> </jats:list-item> </jats:list> </jats:p>