Catálogo de publicaciones - revistas

<jats:title>A route to nitrile that bypasses cyanide</jats:title> <jats:p> The toxicity of hydrogen cyanide (HCN) is well known. Nonetheless, numerous useful nitrile compounds contain CN groups, and the reaction of HCN with C=C double bonds is often used. Fang <jats:italic>et al.</jats:italic> now report an alternative to shuttle a CN group from one molecule to another that relies on Ni and Al catalysts (see the Perspective by Schmalz). This transfer procedure circumvents the need for HCN and can be applied to complex substrates using a simple sacrificial nitrile donor. It can also be run “in reverse” to derive an olefin of interest from a nitrile precursor. </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="6275" page="832" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aae0427">832</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6275" page="817" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aaf2215">817</jats:related-article> </jats:p>

<jats:title>Sensing single proteins with diamonds</jats:title> <jats:p> Nuclear magnetic resonance is a powerful technique for medical imaging and the structural analysis of materials, but is usually associated with large-volume samples. Lovchinsky <jats:italic>et al.</jats:italic> exploited the magnetic properties of a single spin associated with a defect in diamond and manipulated it with a quantum-logic protocol. They demonstrated the magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to a specially treated diamond surface at room temperature. </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="6275" page="836" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad8022">836</jats:related-article> </jats:p>

<jats:title>Dynamic DNA clustering of nanoparticles</jats:title> <jats:p> The size and shape of nanoparticles can increase the cellular uptake and delivery of contrast agents and therapeutics. Ohta <jats:italic>et al.</jats:italic> created gold nanoparticles partly covered with DNA chains and with folic acid as the targeting molecule (see the Perspective by Parak). The particles could link together to hide the folic acid or to expose it on the surface, depending on the hybridization and overall particle configuration. The addition of complementary DNA allowed switching between structures, thus changing the way the particles interacted with cells. </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="6275" page="841" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad4925">841</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6275" page="814" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aaf0751">814</jats:related-article> </jats:p>

<jats:title>A key player in cancer prevention</jats:title> <jats:p> Obstacles that block DNA replication can lead to chromosomal abnormalities and ultimately cancer. Fanconi anemia, for example, is caused by defects in the repair of DNA interstrand cross-links. The Fan1 nuclease was originally identified as a protein essential for this cross-link repair. Lachaud <jats:italic>et al</jats:italic> . now show that it does much more. It is recruited to stalled replication forks by ubiquitinated Fancd2 enabling the processing of these structures, thereby preventing chromosomal abnormalities and acting more broadly in cancer prevention. </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="6275" page="846" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad5634">846</jats:related-article> </jats:p>

<jats:title>Glial cell properties dictated by neurons</jats:title> <jats:p> Neurons in the brain coexist with astrocytes, a type of glial cell, which help support many functions of their neighboring nerve cells. Farmer <jats:italic>et al.</jats:italic> now show that the support goes both ways (see the Perspective by Stevens and Muthukumar). They explored the influence of neurons on two specialized types of astrocytes in the mouse cerebellar cortex. The neurons produced the morphogen known as Sonic Hedgehog. Hedgehog signaling adjusted distinctive gene expression within the two astrocyte cell types. Thus, mature neurons appear to promote and maintain specific properties of associated astrocytes. </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="6275" page="849" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aab3103">849</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6275" page="813" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aaf2849">813</jats:related-article> </jats:p>

<jats:title>Microbiota and infant development</jats:title> <jats:p> Malnutrition in children is a persistent challenge that is not always remedied by improvements in nutrition. This is because a characteristic community of gut microbes seems to mediate some of the pathology. Human gut microbes can be transplanted effectively into germ-free mice to recapitulate their associated phenotypes. Using this model, Blanton <jats:italic>et al.</jats:italic> found that the microbiota of healthy children relieved the harmful effects on growth caused by the microbiota of malnourished children. In infant mammals, chronic undernutrition results in growth hormone resistance and stunting. In mice, Schwarzer <jats:italic>et al.</jats:italic> showed that strains of <jats:italic>Lactobacillus plantarum</jats:italic> in the gut microbiota sustained growth hormone activity via signaling pathways in the liver, thus overcoming growth hormone resistance. Together these studies reveal that specific beneficial microbes could potentially be exploited to resolve undernutrition syndromes. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aad3311">10.1126/science.aad3311</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6275" page="854" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad8588">854</jats:related-article> </jats:p>

<jats:title>Keeping immune cells quiet on a diet</jats:title> <jats:p> Over thousands of years, our immune systems has evolved to distinguish self from foreign, perpetrating attacks on microbes but not ourselves. Given this, why do we fail to mount an immune response against most of the food we eat? Kim <jats:italic>et al.</jats:italic> compared normal mice, mice lacking microbes, and mice lacking microbes that were fed an elemental diet devoid of dietary antigens (see the Perspective by Kuhn and Weiner). Dietary antigens normally induced a population of suppressive immune cells called regulatory T cells in the small intestine. The cells were distinct from regulatory T cells induced by microbial antigens and prevented strong reactions against food. </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="6275" page="858" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aac5560">858</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6275" page="810" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aaf2167">810</jats:related-article> </jats:p>