Catálogo de publicaciones - revistas

<jats:title>Mechanically detected spin resonances</jats:title> <jats:p> The interaction of spins in a sample with a magnetic field can generate forces that can be sensed with cantilever probes. Losby <jats:italic>et al.</jats:italic> measured the resonance signals at room temperature with a micromechanical torque magnetometer. The difference between two applied radio-frequency signals corresponded to the mechanical frequency of the resonator. This approach revealed the vortex core dynamics of the ferri-toferro–magnetic transition in a micrometer-sized yttrium-iron-garnet single-crystal disk. </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="6262" page="798" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad2449">798</jats:related-article> </jats:p>

<jats:title>LMC pulsar's bright gamma-ray flashes</jats:title> <jats:p>Pulsars are rapidly rotating neutron stars that are seen as pulsating sources of radio waves. Some, such as the Crab pulsar, also emit pulses of gamma rays. The Fermi LAT collaboration observed pulsed gamma rays from a pulsar outside our galaxy, the Milky Way. The pulsar, known as PSR J0540–6919, is located in the Large Magellanic Cloud (LMC). This is the most powerful gamma-ray pulsar yet known, with luminosity 20 times that of the Crab. The findings should help to explain how pulsars convert the energy stored in their rotation into detectable electromagnetic emission.</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="6262" page="801" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac7400">801</jats:related-article> </jats:p>

<jats:title>Moving mammoths</jats:title> <jats:p>Mammoths are a particularly charismatic example of our Pleistocene megafuana. Lister and Sher took a detailed look at mammoth fossils globally and suggest that the North American Columbian mammoth, thought to have arisen from a European species, probably evolved from a more advanced Asian species. Similar dispersal events of Asian mammoths led to later colonization events in Europe and North America.</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="6262" page="805" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac5660">805</jats:related-article> </jats:p>

<jats:p> Several studies have documented fish populations changing in response to long-term warming. Over the past decade, sea surface temperatures in the Gulf of Maine increased faster than 99% of the global ocean. The warming, which was related to a northward shift in the Gulf Stream and to changes in the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation, led to reduced recruitment and increased mortality in the region’s Atlantic cod ( <jats:italic>Gadus morhua</jats:italic> ) stock. Failure to recognize the impact of warming on cod contributed to overfishing. Recovery of this fishery depends on sound management, but the size of the stock depends on future temperature conditions. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management. </jats:p>

<jats:title>The small will inherit the Earth…</jats:title> <jats:p> Understanding how communities and ecosystems recovered from the previous five global extinction events sheds light on how extinctions shape broad patterns of biodiversity. Sallan <jats:italic>et al.</jats:italic> looked across vertebrate species during and after the Devonian extinction (see the Perspective by Wagner). Small-bodied species, with rapid reproductive rates, dominated post-extinction communities, despite the presence of many successful large-bodied species before the extinction. This pattern mimics, to some degree, current patterns of extinction, suggesting that we might expect similar loss of large-bodied species if we continue along our current path. </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="6262" page="812" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac7373">812</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6262" page="736" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad6283">736</jats:related-article> </jats:p>

<jats:p> The relationship between microRNA (miRNA) regulation and the specification of behavior is only beginning to be explored. We found that mutation of a single miRNA locus ( <jats:italic>miR-iab4/iab8</jats:italic> ) in <jats:italic>Drosophila</jats:italic> larvae affects the animal’s capacity to correct its orientation if turned upside down (self-righting). One of the miRNA targets involved in this behavior is the <jats:italic>Hox</jats:italic> gene <jats:italic>Ultrabithorax</jats:italic> , whose derepression in two metameric neurons leads to self-righting defects. In vivo neural activity analysis reveals that these neurons, the self-righting node (SRN), have different activity patterns in wild type and miRNA mutants, whereas thermogenetic manipulation of SRN activity results in changes in self-righting behavior. Our work thus reveals a miRNA-encoded behavior and suggests that other miRNAs might also be involved in behavioral control in <jats:italic>Drosophila</jats:italic> and other species. </jats:p>

<jats:title>Ancient African helps to explain the present</jats:title> <jats:p> Tracing the migrations of anatomically modern humans has been complicated by human movements both out of and into Africa, especially in relatively recent history. Gallego Llorente <jats:italic>et al.</jats:italic> sequenced an Ethiopian individual, “Mota,” who lived approximately 4500 years ago, predating one such wave of individuals into Africa from Eurasia. The genetic information from Mota suggests that present-day Sardinians were the likely source of the Eurasian backflow. Furthermore, 4 to 7% of most African genomes, including Yoruba and Mbuti Pygmies, originated from this Eurasian gene flow. </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="6262" page="820" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad2879">820</jats:related-article> </jats:p>

<jats:title>Genome editing with a Cas9 scalpel</jats:title> <jats:p> The Cas9 nuclease forms the heart of the CRISPR-Cas genome editing system. Cas9 binds small guide RNAs that direct it to its target sites, where the nuclease either cleaves or binds to genomic DNA. Knight <jats:italic>et al.</jats:italic> used single-molecule imaging to track Cas9 in living cells. Cas9 searches the genome for its target sites using rapid threedimensional diffusion. It spends very little time binding to off-target sites, which explains the high accuracy of the CRISPRCas9 editing machine. </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="6262" page="823" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac6572">823</jats:related-article> </jats:p>

<jats:title>Nlrp6 keeps gut infections in check</jats:title> <jats:p> Most viruses infect only certain cells of the body. Enteric viruses, such as norovirus and rotavirus, specifically infect the gut. Wang <jats:italic>et al.</jats:italic> now show that the response to such viruses is tissue-specific, too. Antiviral immunity to enteric but not systemic viral infections in mice required Nlrp6, a member of the NOD-like receptor family of proteins that play important roles in host defense. Together with the RNA helicase protein Dhx15, Nlrp6 bound viral RNA and elicited downstream antiviral immune responses necessary for viral clearance. These included the production of type I and type III interferons and the expression of interferon-stimulated genes. </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="6262" page="826" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aab3145">826</jats:related-article> </jats:p>

<jats:title>A gut bacterial containment system</jats:title> <jats:p> Trillions of bacteria selectively inhabit our guts, but how do our bodies keep them contained? Spadoni <jats:italic>et al.</jats:italic> describe a “gut-vascular barrier” that prevents intestinal microbes from accessing the liver and the bloodstream in mice (see the Perspective by Bouziat and Jabri). Studies with human samples and in mice revealed that the cell biology of the gut-vascular barrier shares similarities with the blood-brain barrier of the central nervous system. Pathogenic bacteria such as <jats:italic>Salmonella typhimurium</jats:italic> could penetrate the gut-vascular barrier in mice, gaining access to the liver and bloodstream, in a manner dependent on the <jats:italic>Salmonella</jats:italic> pathogenicity island 2–type III secretion system. </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="6262" page="830" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad0135">830</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6262" page="742" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad6768">742</jats:related-article> </jats:p>