Catálogo de publicaciones - revistas

<jats:title>Displacing OH groups catalytically</jats:title> <jats:p> The Mitsunobu reaction is widely used to invert the configuration of alcohols. However, its major drawback is the need to activate the alcohol with a full equivalent of phosphine, thereby generating a phosphine oxide co-product. Beddoe <jats:italic>et al.</jats:italic> report a phosphine oxide compound that achieves the same result catalytically (see the Perspective by Longwitz and Werner). The key is a phenol substituent that can reversibly bond through its oxygen to phosphorus, forming a ring that the alcohol opens. The phosphorus thus remains in the +5 oxidation state throughout the reaction, and water is the only by-product. </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="6456" page="910" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax3353">910</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6456" page="866" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay6635">866</jats:related-article> </jats:p>

<jats:title>Skyrmions in a frustrated magnet</jats:title> <jats:p> Skyrmions—tiny, topologically protected whirlpools of spin—have been investigated as potential information carriers in spintronic devices. Usually, skyrmions appear in noncentrosymmetric materials or at interfaces between materials. In contrast to this rule of thumb, Kurumaji <jats:italic>et al.</jats:italic> observed a skyrmion lattice phase in the centrosymmetric material Gd <jats:sub>2</jats:sub> PdSi <jats:sub>3</jats:sub> . The magnetic frustration present in this material helped stabilize the skyrmion phase, which was detected through transport measurements in magnetic field. </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="6456" page="914" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aau0968">914</jats:related-article> </jats:p>

<jats:title>Microbial tRNA pieces regulate nodulation</jats:title> <jats:p> To fix nitrogen, leguminous plants enter into a symbiotic relationship with nodulating bacteria. Ren <jats:italic>et al.</jats:italic> now reveal the bacteria as active regulators in this process (see the Perspective by Baldrich and Meyers). Small fragments cleaved from rhizobial tRNA molecules tap into the hosts' RNA interference machinery to silence key host genes. Thus, both host and microbe shape the symbiotic environment. </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="6456" page="919" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aav8907">919</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6456" page="868" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay7101">868</jats:related-article> </jats:p>

<jats:title>Programmable genome engineering</jats:title> <jats:p> The model bacterium <jats:italic>Escherichia coli</jats:italic> has a single circular chromosome. Wang <jats:italic>et al.</jats:italic> created a method to fragment the <jats:italic>E. coli</jats:italic> genome into independent chromosomes that can be modified, rearranged, and recombined. The efficient fission of the unmodified <jats:italic>E. coli</jats:italic> genome into two defined, stable pairs of synthetic chromosomes provides common intermediates for large-scale genome manipulations such as inversion and translocation. Fusion of synthetic chromosomes from distinct cells generated a single genome in a target cell. Precise, rapid, large-scale genome engineering operations are useful tools for creating diverse synthetic genomes. </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="6456" page="922" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aay0737">922</jats:related-article> </jats:p>

<jats:title>Filling a dating hole</jats:title> <jats:p>The periodic nature of Earth's orbit around the Sun produces cycles of insolation reflected in climate records. Conversely, these climate records can be used to infer changes in the dynamics of the Solar System, which is inherently chaotic and not always similarly periodic. A particular obstacle is the lack of well-defined planetary orbital constraints between 50 and 60 million years ago. Zeebe and Lourens found an astronomical solution for that interval showing that the Solar System experienced a specific resonance transition pattern. These data provide a measure of the duration of the Paleocene-Eocene Thermal Maximum.</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="6456" page="926" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aax0612">926</jats:related-article> </jats:p>

<jats:title>A dynamic signaling scaffold</jats:title> <jats:p> In neurons, many cellular processes are regulated by receptor tyrosine kinases (RTKs), cell surface receptors whose activation can depend on other signaling pathways. Zhou <jats:italic>et al.</jats:italic> used super-resolution imaging to visualize colocalization of signaling proteins on the membrane-associated periodic skeleton (MPS) that is formed by actin, spectrin, and related molecules in the axons and dendrites of neurons. The colocalization of signaling proteins in different pathways leads to transactivation of RTK, which initiates intracellular signaling. In a negative feedback loop, the downstream signaling in turn leads to degradation of the MPS. Thus, the MPS is a dynamically regulated platform that coordinates signal transduction in neurons. </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="6456" page="929" related-article-type="in-this-issue" vol="365" xlink:href="10.1126/science.aaw5937">929</jats:related-article> </jats:p>

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