Catálogo de publicaciones - revistas

<jats:title>The tropical impact of iceberg armadas</jats:title> <jats:p> The massive discharges of icebergs from the Greenland ice sheet during the Last Glacial Period are called Heinrich events. But did Heinrich events cause abrupt climate change, or were they a product of it? Methane levels represent a proxy for climate, because methane production increases mostly due to wetter conditions in the tropics. Rhodes <jats:italic>et al.</jats:italic> report a highly resolved record of atmospheric methane concentrations, derived from an ice core from Antarctica. Methane levels varied—i.e., the tropical climate changed—in response to cooling in the Northern Hemisphere caused by Heinrich events. </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="6238" page="1016" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1262005">1016</jats:related-article> </jats:p>

<jats:title>Quasi-sexual microbe populations</jats:title> <jats:p> Astonishing levels of fine-scale microbial diversity have been uncovered by DNA sequencing of natural populations. How this diversity is shaped and maintained and what its environmental or clinical implications might be is unclear. Using custom-made advanced statistical methods, Rosen <jats:italic>et al.</jats:italic> analyzed the evolutionary structure of a photosynthetic bacterium that grows in the hot springs of Yellowstone Park (see the Perspective by Desai and Walczak). The populations behaved neither as clones nor “ecotypes” but more like sexual organisms. These cyanobacteria have high recombination rates that maintain diversity and prevent selective sweeps that would otherwise reduce diversity. </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="6238" page="1019" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa4456">1019</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6238" page="977" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab3957">977</jats:related-article> </jats:p>

<jats:title>Stretching cell sheets promotes proliferation</jats:title> <jats:p> Mechanical strain regulates the development, organization, and function of multicellular tissues. But how? Cadherins mechanically couple neighboring epithelial cells through extracellular interactions and sequester the transcription factors β-catenin and Yap1. To find out more, Benham-Pyle <jats:italic>et al.</jats:italic> stretched epithelial cell sheets. This mechanical strain induced rapid cell cycle reentry, DNA synthesis by sequential nuclear accumulation, and transcriptional activation of Yap1 and β-catenin. Thus, cell-cell junctions are mechanically responsive structural scaffolds providing signaling centers that coordinate transcriptional responses to externally applied force. </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="6238" page="1024" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa4559">1024</jats:related-article> </jats:p>

<jats:title>Identification of a memory drug target</jats:title> <jats:p> ISRIB is a potent inhibitor of the integrated stress response (ISR), which involves the activation of eIF2α-specific kinases, phosphorylation of eIF2α, and consequent down-regulation of global translation levels. ISRIB is also a candidate drug for treating certain memory disorders. ISRIB does not prevent eIF2α phosphorylation and must therefore act downstream of this step. Sekine <jats:italic>et al.</jats:italic> now report that ISRIB reverses the inhibitory effect of eIF2α phosphorylation on the activity of eIF2B, a dedicated guanine nucleotide exchange factor, enhancing its activity independently of phosphorylation (see the Perspective by Hinnebusch). The authors isolated ISRIB-resistant cells and identified a genetic lesion in a short N-terminal region of eIF2Bδ that appears to be responsible for the observed phenotype. </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="6238" page="1027" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa6986">1027</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6238" page="967" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aac4832">967</jats:related-article> </jats:p>

<jats:title>Innate lymphoid cells keep gut T cells in check</jats:title> <jats:p> Trillions of bacteria inhabit our guts. So do many types of immune cells, including T cells, which might be expected to attack these bacteria. How, then, do our bodies manage to keep the peace? Working in mice, Hepworth <jats:italic>et al.</jats:italic> report one such mechanism. A population of immune cells, called innate lymphoid cells, directly killed CD4 <jats:sup>+</jats:sup> T cells that react to commensal gut microbes. Some of the specifics of this process parallel how the immune system keeps developing self-reactive T cells in check in the thymus. Furthermore, this peacekeeping process may be disrupted in children with inflammatory bowel disease. </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="6238" page="1031" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa4812">1031</jats:related-article> </jats:p>

<jats:title>A mutant promoter's partner in crime</jats:title> <jats:p> Telomerase is an enzyme that maintains the ends of chromosomes. <jats:italic>TERT</jats:italic> , the gene coding for the enzyme's catalytic subunit, is not expressed in healthy somatic cells, but its expression is reactivated in the majority of human cancers. The resultant high levels of telomerase help cancer cells survive and multiply. Recurrent mutations in the promoter region of <jats:italic>TERT</jats:italic> are associated with high telomerase levels in multiple cancer types. Bell <jats:italic>et al.</jats:italic> show that a specific transcription factor called GABP is selectively recruited to the mutant form of the <jats:italic>TERT</jats:italic> promoter, which activates <jats:italic>TERT</jats:italic> gene expression </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="6238" page="1036" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab0015">1036</jats:related-article> </jats:p>

<jats:title>How to generate head-to-tail polarity in a midge</jats:title> <jats:p> Animal genomes do not remain static but gain and lose essential genes over time. One such case is the <jats:italic>bicoid</jats:italic> gene of flies. <jats:italic>Bicoid</jats:italic> plays an important role in early <jats:italic>Drosophila</jats:italic> development during the generation of head-to-tail polarity, but most flies lack <jats:italic>bicoid.</jats:italic> Which genes then serve the same function in other insects? Now, Klomp <jats:italic>et al.</jats:italic> report a structurally unrelated gene that serves essentially the same function as <jats:italic>bicoid</jats:italic> in a mosquito-related midge but does so through a different genetic mechanism. </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="6238" page="1040" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa7105">1040</jats:related-article> </jats:p>

<jats:p> Advancements in genetics, sequencing technology, and bioinformatics are changing the principles of current medical practice and transforming the standards of patient care. Genetic detection of common and rare variants within populations provides valuable information about predisposition and vulnerability to complex human disease. Data from large-scale genome-wide association studies have identified genetic variations correlated to biological events, enabling combinations of genetic and non-genetic markers to be translated into potential diagnostic tools. However, aspects of these programs are still evolving, including best practices for protocol development, sample processing, genetic/genomic analysis, data management, and quality control. In this webinar, our expert panel will discuss how to better define these procedures and maximize the use of precious, limited clinical samples by utilizing recent innovations, advances in technology, and current best practices. <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/advances-addiction-research">View the Webinar</jats:ext-link> </jats:p> </jats:list-item> </jats:list> </jats:p>

<jats:p>On this week's show: A changing climate for China's tea crop, and a roundup of daily news stories.</jats:p>

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