Catálogo de publicaciones - revistas

<jats:p>Neurons that stabilize memory storage are located outside of a region in the insect brain long thought to handle this task.</jats:p>

<jats:p>Most reported power laws lack statistical support and mechanistic backing.</jats:p>

<jats:p>Self-tolerant T cells can be transiently reactivated.</jats:p>

<jats:p>The conformation of the complex formed by a catalyst and its substrate was determined with a method that combined mass spectrometry and infrared spectroscopy.</jats:p>

<jats:p> The structure of a sodium-calcium exchange protein provides insight into the mechanism of Ca <jats:sup>2+</jats:sup> transport through the cell membrane. </jats:p>

<jats:title>Spring Bloom</jats:title> <jats:p> The spring bloom of plankton in northern seas develops apparently in response to increasing light and to winter weather, which make nutrients available at the surface. This seasonality is important on a global scale because it reflects a tipping point, driven by phytoplankton growth, between CO <jats:sub>2</jats:sub> production and carbon storage. The phenomenon is thus of particular interest in this era of carbon excess. <jats:bold>Giovannoni and Vergin</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="671" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1198078">671</jats:related-article> ) review what is known about the dynamics of these highly ordered microbial plankton communities, discuss the specialist roles of certain taxa, and reflect on predictions for anthropogenic changes to the oceans and what these might mean for geochemical cycles driven by ocean microbiota. </jats:p>

<jats:p>Cell culture experiments reveal that direct interactions between pigment cells play a key role in skin pattern formation.</jats:p>

<jats:title>Challenging the Mushroom Bodies</jats:title> <jats:p> Early memory is labile and is gradually consolidated over time into long-lasting, stable memory. In several species, including mammals, memory consolidation depends on protein synthesis. In <jats:italic>Drosophila</jats:italic> , long-term memory is produced by spaced repetitive training, which induces cyclic adenosine monophosphate (cAMP)–response element–binding protein (CREB)–dependent gene transcription and de novo protein synthesis. Using a large number of genetic tools, <jats:bold> Chen <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="678" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1212735">678</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="6069" page="664" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1218171">Dubnau</jats:related-article> </jats:bold> ) localized this CREB-dependent induction of de novo protein synthesis to two dorsal-anterior-lateral neurons in the adult brain. Importantly, protein synthesis was not required within the mushroom bodies, which are usually considered to be the site of associative learning and memory in insects. </jats:p>

<jats:title>Maintaining Equilibrium</jats:title> <jats:p> Na <jats:sup>+</jats:sup> /Ca <jats:sup>2+</jats:sup> exchangers (NCX) are membrane transporters that maintain the homeostasis of cytosolic Ca <jats:sup>2+</jats:sup> and play an essential role in Ca <jats:sup>2+</jats:sup> signaling. Despite a long history of physiological work and a large body of functional data, the structural basis underlying the ion exchange mechanism of NCX is poorly understood. <jats:bold> Liao <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="686" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1215759">686</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6069" page="669" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1218696"> <jats:bold> Abramson <jats:italic>et al.</jats:italic> </jats:bold> </jats:related-article> ) present a high-resolution crystal structure of an NCX from <jats:italic>Methanococcus jannaschii</jats:italic> and demonstrate that this archaeal NCX catalyzes Na <jats:sup>+</jats:sup> /Ca <jats:sup>2+</jats:sup> -exchange reactions similar to its eukaryotic counterpart. The structure clarifies the mechanism of ion exchange proteins and reveals the basis for the stoichiometry, cooperativity, and bidirectionality of the reaction. </jats:p>

<jats:title>Be My Guests</jats:title> <jats:p> For a range of applications, including medical diagnostics or drug delivery, it is necessary to encapsulate one or more components into a microcapsule. While there are many methods that can do this, most either produce a range of capsule size or are not easily scalable for making large quantities. <jats:bold> J. Zhang <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="690" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1215416">690</jats:related-article> ) developed a microfluidic-based system for making capsules using host-guest chemistry. Cucurbit[8]uril, which readily forms complexes in water, was used as the host molecule and could accommodate two different guest molecules. Rapid complexation was observed of methyl viologen–modified gold nanoparticles and a naphthol-containing copolymer. </jats:p>