Catálogo de publicaciones - revistas

<jats:title>Riding the Wind</jats:title> <jats:p> Pelagic seabirds rely on wind to move between breeding and foraging areas, and albatrosses—which travel thousands of kilometers over sea—are well-known wind riders. <jats:bold> Weimerskirch <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="211" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1210270">211</jats:related-article> ; see the cover) monitored foraging and reproduction in wandering albatrosses over 40 years and found that a change in wind patterns, probably induced by climate change, had a notable impact on important life history traits. Greater wind strength increased the rate of travel for the birds and shortened their foraging trips. These shorter trips improved breeding success and resulted in an increase in adult mass. Thus, over the past half-century, environmental changes have improved conditions for the albatross. </jats:p>

<jats:title>Global Ecosystem Analysis</jats:title> <jats:p> The relationship between species richness and the functional properties of their ecosystems has often been studied at small scales in experimental plots. <jats:bold> Maestre <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="214" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1215442">214</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6065" page="174" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1217245">Midgley</jats:related-article> </jats:bold> ) performed field measurements at 224 dryland sites from six continents and assessed 14 ecosystem functions related to carbon, nitrogen, and phosphorus cycling. Positive relationships were observed between perennial plant species richness and ecosystem functionality. The relative importance of biodiversity was found to be as large as, or larger than, many key abiotic variables. Thus, preservation of plant biodiversity is important to buffer negative effects of climate change and desertification in drylands, which collectively cover 41% of Earth's land surface and support over 38% of the human population. </jats:p>

<jats:title>Parasite Invasion Strategy</jats:title> <jats:p> Exocytosis is essential to the lytic cycle of apicomplexan parasites and is required for the pathogenesis of toxoplasmosis and malaria. DOC2 proteins recruit the membrane fusion machinery required for exocytosis in a Ca <jats:sup>2+</jats:sup> -dependent fashion. <jats:bold> Farrell <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="218" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1210829">218</jats:related-article> ) describe the phenotype of a <jats:italic>Toxoplasma gondii</jats:italic> conditional mutant impaired in host cell invasion and egress. The phenotype was explained by a defect in secretion of the micronemes, an apicomplexan-specific organelle that contains adhesion proteins. A <jats:italic>T. gondii</jats:italic> Doc2 gene was identified, by whole-genome sequencing, to be involved in the secretion defect, and a conditional allele of the orthologous gene engineered into the malaria parasite, <jats:italic>Plasmodium falciparum</jats:italic> , also caused defects in microneme secretion. </jats:p>

<jats:title>Doing the Side Step</jats:title> <jats:p> The molecular motor, dynein, contains two ring domains responsible for its movement along the microtubule. However, how the rings move relative to each other during processive motility and whether dynein processivity requires interhead coordination are unclear. To directly observe how dynein “walks” along microtubules, <jats:bold> DeWitt <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="221" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1215804">221</jats:related-article> , published online 8 December) performed advanced fluorescence-imaging studies to follow both motor domains of a single dynein motor at nanometer resolution. The data suggest that the two heads do not cooperate during movement, which suggests a fundamentally different mechanism of motility from that observed for other microtubule-based motors. </jats:p>

<jats:title>TACE Trafficking</jats:title> <jats:p> The cytokine tumor necrosis factor (TNF) is a major driver of inflammation and contributes to the immune pathology seen in a variety of diseases, including inflammatory bowel disease, rheumatoid arthritis, and sepsis. Soluble TNF is produced by cleavage of its ectodomain by the ADAM family metalloprotease, TNFα-converting enzyme (TACE). However, the molecular regulation of TACE is not understood (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6065" page="179" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1216815">Lichtenthaler</jats:related-article> </jats:bold> ). <jats:bold> Adrain <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="225" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1214400">225</jats:related-article> ) and <jats:bold> McIlwain <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="229" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1214448">229</jats:related-article> ) now show that the rhomboid family member iRhom2 interacts with TACE in macrophages and is required for its proper intracellular trafficking and activation. In the absence of iRhom2, TACE was not released from the endoplasmic reticulum, and active protease did not reach the cell surface. Because of an inability to produce TNF, iRhom2-deficient mice were more resistant to lipopolysaccharide-induced septic shock but could not adequately control a <jats:italic>Listeria monocytogenes</jats:italic> infection. </jats:p>

<jats:title>TACE Trafficking</jats:title> <jats:p> The cytokine tumor necrosis factor (TNF) is a major driver of inflammation and contributes to the immune pathology seen in a variety of diseases, including inflammatory bowel disease, rheumatoid arthritis, and sepsis. Soluble TNF is produced by cleavage of its ectodomain by the ADAM family metalloprotease, TNFα-converting enzyme (TACE). However, the molecular regulation of TACE is not understood (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6065" page="179" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1216815">Lichtenthaler</jats:related-article> </jats:bold> ). <jats:bold> Adrain <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="225" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1214400">225</jats:related-article> ) and <jats:bold> McIlwain <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="229" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1214448">229</jats:related-article> ) now show that the rhomboid family member iRhom2 interacts with TACE in macrophages and is required for its proper intracellular trafficking and activation. In the absence of iRhom2, TACE was not released from the endoplasmic reticulum, and active protease did not reach the cell surface. Because of an inability to produce TNF, iRhom2-deficient mice were more resistant to lipopolysaccharide-induced septic shock but could not adequately control a <jats:italic>Listeria monocytogenes</jats:italic> infection. </jats:p>

<jats:title>Fluoride Riboswitch</jats:title> <jats:p> Riboswitches are found in prokaryote and eukaryote messenger RNAs (mRNAs), where they regulate expression of the linked mRNA through ligand binding and conformational change. <jats:bold> Baker <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="233" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1215063">233</jats:related-article> , published online 22 December) analyzed the binding properties of the “ <jats:italic>crcB</jats:italic> motif” found in the noncoding RNA at the 5′ end of a diverse collection of prokaryotic genes. A <jats:italic>crcB</jats:italic> motif from <jats:italic>Pseudomonas syringae</jats:italic> was capable of selectively sensing the very small and highly charged fluoride ion. Some of the <jats:italic>crcB</jats:italic> and <jats:italic>eriC</jats:italic> genes associated with the fluoride riboswitch showed evidence of being fluoride transporters. The bacterium <jats:italic>Methylobacterium extorquens</jats:italic> DM4, which can use halogenated hydrocarbons as an energy source, was found to encode at least 10 fluoride riboswitches in its genome. </jats:p>

<jats:title>Long-Lasting Pain Killers</jats:title> <jats:p> Opioids are among the most widely used and extensively studied drugs in the world. A continuous application of relatively low opioid doses is thought to be necessary to maintain synaptic depression in pain pathways. <jats:bold> Drdla-Schutting <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="235" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1211726">235</jats:related-article> ) found that a single opioid application could produce lasting reversal of synaptic long-term potentiation in pain pathways. Chronic pain is often associated with synaptic potentiation in nociceptive pathways. A brief, high-dose application of opioids depotentiated long-term potentiation in spinal pain pathways. The same dose also reversed hyperalgesia in behaving animals. Thus, opioids not only attenuate pain but also may eradicate a significant cause for chronic pain. </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 show includes cost-effectively combating climate change, female leadership's effect on young girls, peopling the Aleutian Islands, and more.</jats:p>