Catálogo de publicaciones - revistas

<jats:title>Catalysis in the Membrane</jats:title> <jats:p> Enzymes in the UbiA superfamily of integral membrane proteins synthesize lipid-soluble aromatics such as ubiquinones and chlorophylls that function in energy storage and energy transfer in mitochondrial and chloroplast membranes. <jats:bold>Cheng and Li</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="878" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1246774">878</jats:related-article> ) report structures of an archaeal UbiA protein in both apo and substrate-bound states. The structures show a large active site with a lateral portal that is likely to give access to the long-chain isoprenoid substrates. The findings suggest a mechanism for substrate recognition and catalysis and can explain disease-related mutants in eukaryotic homologs. </jats:p>

<jats:title>Two-Faced Viral Protein</jats:title> <jats:p> Flaviviruses cause human diseases such as West Nile fever and dengue fever. The flavivirus nonstructural protein 1 (NS1) has multiple functions in flavivirus biology and is a target for vaccine development. Dimeric NS1 is essential for replication of the viral genome inside host cells, while hexameric NS1 is secreted and plays a role in evasion of the immune system. <jats:bold> Akey <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="881" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1247749">881</jats:related-article> , published online 6 February; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="849" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1251249">Shi</jats:related-article> </jats:bold> ) report crystal structures for full-length glycosylated NS1 from West Nile and dengue viruses. The structures show a hexamer comprised of three dimers. The structural analysis together with liposome and mutational studies identify a membrane interacting surface on one face of the dimer and an immune evasion surface on the other. </jats:p>

<jats:title>Toward Successful Tissue Repair</jats:title> <jats:p> The therapeutic use of growth factors in tissue regeneration has suffered from safety and efficacy issues. Reasoning that the unmet potential may be because of nonphysiological delivery, <jats:bold> Martino <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="885" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1247663">885</jats:related-article> ) engineered growth factors to bind strongly to extracellular matrix proteins. These variants were able to induce superior tissue repair, compared to the wild-type proteins. Furthermore, unwanted side effects were decreased: For example, the engineered angiogenic growth factor VEGF showed reduced vascular permeability, a concern that has limited the therapeutic efficacy of wild-type VEGF. </jats:p>

<jats:title>Oops, That's Not Right…</jats:title> <jats:p> Evaluating our actions, and detecting our errors, is crucial for adaptive behavior. These fundamental executive functions are intensively studied in cognitive and social neuroscience, but their anatomical basis remains poorly characterized. Using intracerebral electroencephalography in patients being prepared for epilepsy surgery, <jats:bold> Bonini <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="888" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1247412">888</jats:related-article> ) found that, contrary to what is widely assumed, the supplementary motor area, and not the anterior cingulate cortex, plays a leading role in these processes. The data provide a precise spatio-temporal description of the cortical network underlying action monitoring and error processing. </jats:p>

<jats:title>Entorhinal Cell Clusters</jats:title> <jats:p> There is considerable interest in understanding the function of neurons in layer 2 of the medial entorhinal cortex and how they generate their unique firing patterns, which are important in the recall of facts and past events (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="846" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1251252">Blair</jats:related-article> </jats:bold> ). <jats:bold> Ray <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="891" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1243028">891</jats:related-article> , published online 23 January) investigated principal cells in layer 2 by immunoreactivity, projection patterns, microcircuit analysis, and assessment of temporal discharge properties in awake, freely moving animals. In tangential sections, pyramidal neurons were clustered into patches arranged in a hexagonal grid—very similar to the patterns observed in grid cell spatial firing. These patches received selective cholinergic innervation, which is critical for sustaining grid cell activity. <jats:bold> Kitamura <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="896" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1244634">896</jats:related-article> , published online 23 January) found that these cells drive a hippocampal circuit by projecting directly to the hippocampal CA1 area and synapsing with a distinct class of inhibitory neurons. This circuit provides feed-forward inhibition in combination with excitatory inputs from layer 3 cells of the medial entorhinal cortex, projecting to CA1 pyramidal cells to determine the strength and time window of temporal associative inputs. </jats:p>

<jats:title>Entorhinal Cell Clusters</jats:title> <jats:p> There is considerable interest in understanding the function of neurons in layer 2 of the medial entorhinal cortex and how they generate their unique firing patterns, which are important in the recall of facts and past events (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="846" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1251252">Blair</jats:related-article> </jats:bold> ). <jats:bold> Ray <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="891" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1243028">891</jats:related-article> , published online 23 January) investigated principal cells in layer 2 by immunoreactivity, projection patterns, microcircuit analysis, and assessment of temporal discharge properties in awake, freely moving animals. In tangential sections, pyramidal neurons were clustered into patches arranged in a hexagonal grid—very similar to the patterns observed in grid cell spatial firing. These patches received selective cholinergic innervation, which is critical for sustaining grid cell activity. <jats:bold> Kitamura <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6173" page="896" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1244634">896</jats:related-article> , published online 23 January) found that these cells drive a hippocampal circuit by projecting directly to the hippocampal CA1 area and synapsing with a distinct class of inhibitory neurons. This circuit provides feed-forward inhibition in combination with excitatory inputs from layer 3 cells of the medial entorhinal cortex, projecting to CA1 pyramidal cells to determine the strength and time window of temporal associative inputs. </jats:p>

<jats:p> The 2014 Gordon Research Conference schedule was published on pages 902 to 926 of this issue of the print version of <jats:italic>Science</jats:italic> . The current schedule can also be found online at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.grc.org/">www.grc.org/</jats:ext-link> . </jats:p>

<jats:p>Time was when mass spectrometry was the province of white-coated chemistry Ph.D.s with a secret language all their own. Terms like ion trap and post-source decay, mass-to-charge, and MALDI made the field inaccessible to others. Today, the technique has pushed beyond those narrow confines and entered the biology lab, where it underlies proteomics and biomarker research. But you can also find mass specs in airports and warehouses, and even at the bottom of the ocean. In many cases those instruments are being run not by specially trained researchers, but by TSA agents, soldiers, and first responders. Chalk that up to miniaturization. Researchers have finally figured out how to compress benchtop systems into portable, sometimes handheld gadgets. In so doing, they have created devices that empower not only themselves, but the wider world.</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> <jats:italic>Science</jats:italic> /AAAS and SciLifeLab, a coordinated effort of four Swedish universities, have joined forces in creating the <jats:italic>Science</jats:italic> &amp; SciLifeLab Prize for Young Scientists. </jats:p>