Catálogo de publicaciones - revistas

<jats:title>To Fuse or Not to Fuse?</jats:title> <jats:p> Cell-cell fusion is poorly understood, although we know that in the nematode, <jats:italic>Caenorhabditis elegans</jats:italic> , it involves cell-surface fusogens and in the fly, <jats:italic>Drosophila</jats:italic> , the actin cytoskeleton plays a role. <jats:bold> Shilagardi <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="6130" page="359" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1234781">359</jats:related-article> ) reconstituted a high-efficiency, inducible cell-fusion culture system, in which they found that the <jats:italic>C. elegans</jats:italic> fusogen, Eff-1, induced a low level of cell-cell fusion that was enhanced by coexpression with a cell adhesion molecule, Sticks and stones (Sns), required for myoblast fusion in <jats:italic>Drosophila.</jats:italic> Sns-enhanced cell-cell fusion was mediated by dynamic actin polymerization that generated invasive membrane protrusions at sites of fusion. </jats:p>

<jats:title>Bats, Grids, and Oscillations</jats:title> <jats:p> Nearly all animals move around in a three-dimensional (3D) world; however, very little is known about the neural circuitry underlying the representation of 3D space (see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6130" page="279" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1237569"> <jats:bold>Barry and Doeller</jats:bold> </jats:related-article> ). Using whole-cell patch recordings in slices of entorhinal cortex, <jats:bold> Heys <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="6130" page="363" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1233831">363</jats:related-article> ) found that bat entorhinal stellate cells must generate grid patterns without theta-frequency oscillatory mechanisms. In another study, <jats:bold>Yartsev and Ulanovsky</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6130" page="367" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1235338">367</jats:related-article> ) used telemetry to record activity from the hippocampus of bats while they were flying around. They found that active pyramidal cells—or place cells—in hippocampal area CA1 fired in positions, depending on where the animals were in the room. </jats:p>

<jats:title>Bats, Grids, and Oscillations</jats:title> <jats:p> Nearly all animals move around in a three-dimensional (3D) world; however, very little is known about the neural circuitry underlying the representation of 3D space (see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6130" page="279" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1237569"> <jats:bold>Barry and Doeller</jats:bold> </jats:related-article> ). Using whole-cell patch recordings in slices of entorhinal cortex, <jats:bold> Heys <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="6130" page="363" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1233831">363</jats:related-article> ) found that bat entorhinal stellate cells must generate grid patterns without theta-frequency oscillatory mechanisms. In another study, <jats:bold>Yartsev and Ulanovsky</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6130" page="367" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1235338">367</jats:related-article> ) used telemetry to record activity from the hippocampus of bats while they were flying around. They found that active pyramidal cells—or place cells—in hippocampal area CA1 fired in positions, depending on where the animals were in the room. </jats:p>

<jats:title>Turn Off Youth</jats:title> <jats:p> Our neurons regenerate better when we are young than when we are more mature. Studying the mechanosensory anterior ventral microtubule (AVM) neuron of the nematode <jats:italic>Caenorhabditis elegans</jats:italic> , <jats:bold> Zou <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="6130" page="372" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1231321">372</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6130" page="282" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1237921"> <jats:bold>Nix and Bastiani</jats:bold> </jats:related-article> ) found that worms lacking microRNA machinery had unusually robust axon regeneration and youthful-looking growth cones. Under- and overexpression of <jats:italic>let-7</jats:italic> microRNA confirmed its involvement in depressing axon regeneration. </jats:p>

<jats:title>Consciousness Arrives</jats:title> <jats:p> Neurophysiological measures in human adults correspond to the transition between very brief, “unnoticeable,” and slightly longer-lived visual stimuli that penetrate deeply enough to leave a conscious imprint that subjects report they can “see.” <jats:bold> Kouider <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="6130" page="376" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1232509">376</jats:related-article> ) have performed parallel behavioral and neurophysiological studies in infants to identify a similar neural signal that appears to mark the development of visual consciousness. </jats:p>

<jats:p>The characterization of protein expression systems, particularly for biotherapeutics and structural biology, requires the testing of many variables to obtain the optimal clones. Assessing these variables—including expression system, cell culture, fermentation, and various media components such as growth factors—is costly and time intensive if done individually. However, high throughput analytical technologies and multi-use automation platforms can accommodate the high sample throughput necessary to provide fast, accurate, and efficient optimization of protein expression and purification conditions. This ultimately improves quality, mitigates risk, and accelerates the time to produce proteins for both research and therapeutics applications.</jats:p>

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

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<jats:title>Pulsar Tests Gravity</jats:title> <jats:p> Because of their extremely high densities, massive neutron stars can be used to test gravity. Based on spectroscopy of its white dwarf companion, <jats:bold> Antoniadis <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/340/6131/448.full">448</jats:ext-link> ) identified a millisecond pulsar as a neutron star twice as heavy as the Sun. The observed binary's orbital decay is consistent with that predicted by general relativity, ruling out previously untested strong-field phenomena predicted by alternative theories. The binary system has a peculiar combination of properties and poses a challenge to our understanding of stellar evolution. </jats:p>