Catálogo de publicaciones - revistas

<jats:title>Down with atmospheric carbon dioxide</jats:title> <jats:p> How does the ocean move carbon from surface waters to its deep interior? Current understanding is that carbon dioxide is removed from the atmosphere by phytoplankton that are eaten, and in turn their predators die and sink into deep water and seafloor sediments. In addition to this route, Omand <jats:italic>et al.</jats:italic> show that downwelling caused by ocean eddies 1 to 10 km across can deliver much of the carbon produced in spring to the deep sea. The eddies entrain small particles and dissolved organic carbon to augment the flux of large sinking particles. </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="6231" page="222" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1260062">222</jats:related-article> </jats:p>

<jats:title>Early closing between oceans</jats:title><jats:p>The Central American Seaway, which once separated the Panama Arc from South America, may have closed 10 million years earlier than is believed. Montes<jats:italic>et al.</jats:italic>report that certain minerals of Panamanian provenance began to appear in South America during the Middle Miocene, 15 to 13 million years ago (see the Perspective by Hoorn and Flantua). The presence of the minerals indicates that rivers were flowing from the Panama Arc into the shallow marine basins of northern South America. One interpretation of this finding is that large-scale ocean flow between the Atlantic and Pacific had ended by then. If this is true, then many models of paleo-ocean circulation and biotic exchange between the Americas need to be reconsidered.</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="6231" page="226" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa2815">226</jats:related-article>; see also p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6231" page="186" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab0099">186</jats:related-article></jats:p>

<jats:title>Ocean acidification and mass extinction</jats:title> <jats:p> The largest mass extinction in Earth's history occurred at the Permian-Triassic boundary 252 million years ago. Several ideas have been proposed for what devastated marine life, but scant direct evidence exists. Clarkson <jats:italic>et al.</jats:italic> measured boron isotopes across this period as a highly sensitive proxy for seawater pH. It appears that, although the oceans buffered the acidifiying effects of carbon release from contemporary pulses of volcanism, buffering failed when volcanism increased during the formation of the Siberian Traps. The result was a widespread drop in ocean pH and the elimination of shell-forming organisms. </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="6231" page="229" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa0193">229</jats:related-article> </jats:p>

<jats:title>Making comets in the cold</jats:title> <jats:p> The speciation of nitrogen compounds in comets can tell us about their history. Comets are some of the most ancient bodies in the solar system and should contain the nitrogen compounds that were abundant when they formed. Using the ROSINA mass spectrometer aboard the Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko, Rubin <jats:italic>et al.</jats:italic> found molecular nitrogen at levels that are depleted compared to those in the primordial solar system. Depletion of such a magnitude suggests that the comet formed either from the low-temperature agglomeration of pristine amorphous water ice grains or from clathrates. </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="6231" page="232" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa6100">232</jats:related-article> </jats:p>

<jats:title>Chromosome number varies in humans</jats:title> <jats:p> Pregnancy loss is often associated with a loss of chromosome number, a condition known as aneuploidy. When examining aneuploid embryos during in vitro fertilization cycles, McCoy <jats:italic>et al.</jats:italic> found a large genomic region associated with defects in maternal chromosome number (see the Perspective by Vohr and Green). This region contains a gene, <jats:italic>Polo-like Kinase 4</jats:italic> ( <jats:italic>PLK4</jats:italic> ), that is known to affect chromosome segregation and has variants that correlate with an increased rate of maternal aneuploidy. Surprisingly, such variants occur at relatively high levels in human populations and may be under positive selection. </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="6231" page="235" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa3337">235</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6231" page="180" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab0877">180</jats:related-article> </jats:p>

<jats:title>Giving protein folding a helping hand</jats:title> <jats:p> The reversible phosphorylation of proteins controls virtually all aspects of cell and organismal function. Targeting phosphorylation offers a broad range of therapeutic opportunities, and thus kinases have become important therapeutic targets. As targets, phosphatases should be as attractive, but in fact they are more challenging to manipulate. Das <jats:italic>et al.</jats:italic> have found a safe and specific inhibitor, called Sephin1, that targets a regulatory subunit of protein phosphatase 1 in vivo. Sephin1 binds and inhibits PPP1R15A, but not the related regulatory phosphatase PPP1R15B. In mice, Sephin1 prolonged a stress-induced phospho-signaling pathway to prevent the pathological defects of the unrelated protein-misfolding diseases Charcot-Marie-Tooth 1B and amyotrophic lateral sclerosis. </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="6231" page="239" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa4484">239</jats:related-article> </jats:p>

<jats:title>Genomes in the mist</jats:title> <jats:p> The mountain gorilla is an iconic species that is at high risk of extinction. Xue <jats:italic>et al.</jats:italic> have sequenced 13 gorillas from two different populations to probe their genetic diversity. The genomes show large tracts of homozygosity and the loss of highly deleterious genetic variants, indicating population bottlenecks and inbreeding. This loss of genetic diversity appears to have started over 20,000 years ago and may have been caused by changes in climate and human-associated effects. </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="6231" page="242" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa3952">242</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>New techniques and technologies are constantly being introduced that deepen our understanding of disease and therapeutic pathways. Biochemical screening methods have long been used in drug discovery labs, and more recently also in academic settings. Recent advances in both imaging technology and high throughput automation have led to the development of high-content screening (HCS) and integrated liquid handling systems that have broad application in academia and industry. These advances in image acquisition and automation have transformed numerous fields and have yielded increased data capture and throughput. This webinar will discuss how integrated HCS imaging systems that have been coupled with novel computer modeling are being applied to systems biology, translational cancer research, and personalized medicine.</jats:p>

<jats:p>On this week's show: Mountain gorilla genomes, and a roundup of daily news stories.</jats:p>