Catálogo de publicaciones - revistas

<jats:title>Making an impact in more ways than one</jats:title><jats:p>Massive eruptions formed the Deccan Traps flood basalts in India at around the same time as the mass extinction event 65 million years ago. Renne<jats:italic>et al.</jats:italic>precisely dated the massive volcanic field, which suggests a simultaneous increase in volcanism associated with the famous Chicxulub impact. Strong ecologic recovery may have been impossible until the volcanism slowed down 500,000 years later.</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="6256" page="76" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac7549">76</jats:related-article></jats:p>

<jats:title>How well does water share its protons?</jats:title> <jats:p> Chemists have spent centuries trying to understand what acids look like at the molecular level. It's clear now that water molecules in the liquid accommodate extra protons. Less clear is whether the protons piggyback on individual water molecules (Eigen structure) or find shared accommodation between two at a time (Zundel structure). Thämer <jats:italic>et al.</jats:italic> acquired time-resolved vibrational spectra across an unusually broad span of the mid-infrared, allowing them to monitor stretches and bends at the same time. Their results imply a more prominent role for the Zundel structure than previously anticipated. </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="6256" page="78" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aab3908">78</jats:related-article> </jats:p>

<jats:title>Memory consolidation by gene suppression</jats:title> <jats:p> Storing a persistent memory in the brain involves dynamic gene regulation. However, our knowledge of the target genes controlled during memory formation is limited. Cho <jats:italic>et al.</jats:italic> used RNA sequencing and ribosome profiling to compare transcription and translational levels in the mouse hippocampus before and after memory formation. Under basal conditions, there was an unexpected translational repression of ribosomal protein-coding genes. Early after learning, specific genes were translationally repressed. Later, suppression of a group of genes resulted from the inhibition of estrogen receptor alpha signaling. Thus, suppression mechanisms in the hippocampus appear to play a major role during memory consolidation. </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="6256" page="82" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac7368">82</jats:related-article> </jats:p>

<jats:title>Cloud mixing and droplet evolution</jats:title> <jats:p> When clouds mix with drier air because of atmospheric turbulence, some of the cloud droplets evaporate. Beals <jats:italic>et al.</jats:italic> developed an airborne holographic imaging system to look at changes in the spatial structure and sizes of these droplets (see the Perspective by Bodenschatz). Turbulent mixing of clouds with clear air caused dramatic fluctuations in the number density of water droplets but left their mean diameter essentially unchanged. This finding should help models better represent these hard-to-parameterize cloud processes. </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="6256" page="87" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aab0751">87</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6256" page="40" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad1386">40</jats:related-article> </jats:p>

<jats:title>No precedent</jats:title> <jats:p>Human activities are creating a mass extinction event. The intensity of this event is unprecedented during human times, but there have been several comparable events during Earth's history. Roopnarine and Angielczyk examined one of the largest, the Permian-Triassic Extinction (see the Perspective by Marshall). The structure and diversity of communities were key predictors of stability through the event. Furthermore, extinctions were not random, with smaller-bodied species being more prone to extinction. This pattern is in direct contradiction to the patterns seen in our current extinction. Thus, the current anthropogenically driven extinction is fundamentally different from previous catastrophic extinctions.</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="6256" page="90" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aab1371">90</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6256" page="38" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad2729">38</jats:related-article> </jats:p>

<jats:title>Individualized neuronal mutations in the human brain</jats:title> <jats:p> The neurons of the human brain can last for decades, carrying out computational and signaling functions. Lodato <jats:italic>et al.</jats:italic> analyzed the DNA of individual neurons sampled from postmortem human brains and found that individual neurons acquired somatic mutations (see the Perspective by Linnarsson). The mechanism of mutation involved gene transcription rather than DNA replication. Thus, postmitotic neurons would seem to be their own worst enemy: Genes used for neuronal function are the very genes put most at risk of somatic mutation. </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="6256" page="94" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aab1785">94</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6256" page="37" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad2792">37</jats:related-article> </jats:p>

<jats:title>Motivation helps reverse neuronal damage</jats:title> <jats:p> Motivation plays a fundamental role in mediating recovery after neurological injuries. Sawada <jats:italic>et al.</jats:italic> evaluated the potential contribution of the nucleus accumbens, a brain motivation center, to movement control after spinal cord injury in monkeys. The activity of the nucleus accumbens during the early phase after injury was important for the recovery of motor performance. </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="6256" page="98" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aab3825">98</jats:related-article> </jats:p>

<jats:title>An alternative way of making GABA</jats:title> <jats:p> Midbrain dopaminergic neurons release both the inhibitory neurotransmitter GABA and dopamine. In the central nervous system, GABA synthesis is usually mediated by two glutamate decarboxylases (GAD65 and GAD67). Kim <jats:italic>et al.</jats:italic> found that midbrain dopaminergic neurons use a different, evolutionary conserved GABA synthesis pathway that is independent of GAD65 and GAD67. These cells synthesize GABA from putrescine via the enzymes diamine oxidase and aldehyde dehydrogenase 1a1. GABA synthesized by this pathway accounts for approximately 70% of co-released GABA. </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="6256" page="102" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac4690">102</jats:related-article> </jats:p>

<jats:title>Building a gate to the nucleus</jats:title> <jats:p> Nuclear pore complexes form a gateway between the cytoplasm and the nucleus (see the Perspective by Ullman and Powers). Stuwe <jats:italic>et al.</jats:italic> combined structural, biochemical, and functional analyses to elucidate the architecture of a six-protein complex that makes up the inner ring of the fungal nuclear pore. This includes a central trimeric complex homologous to the Nup62 complex found in metazoans that is incorporated into the nuclear pore inner-ring complex. Chug <jats:italic>et al.</jats:italic> report the structure of the metazoan trimeric Nup62 complex. Neither study supports a model in which the pore can dilate and constrict. Instead they suggest a rigid pore in which flexible domains called FG repeats fill the channel and form a barrier that can be traversed by receptors that carry cargos across. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue pp. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6256" page="56" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac9176">56</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6256" page="106" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac7420">106</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6256" page="33" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad3797">33</jats:related-article> </jats:p>

<jats:p>At first glance, animal nervous systems seem to defy understanding. Even a "simple" animal such as a fly has over 100,000 neurons that can fire in billions of possible combinations, driving precise, nuanced responses to complex environmental stimuli. Nonetheless, evolution has given brains a few features that make them tantalizingly easy to study—at least in theory.</jats:p>