Catálogo de publicaciones - revistas

<jats:title>As with donuts, the holes matter</jats:title> <jats:p> Improving the density of stored charge and increasing the speed at which it can move through a material are usually opposing objectives. Sun <jats:italic>et al.</jats:italic> developed a Nb <jats:sub>2</jats:sub> O <jats:sub>5</jats:sub> /holey graphene framework composite with tailored porosity. The three-dimensional, hierarchically porous holey graphene acted as a conductive scaffold to support Nb <jats:sub>2</jats:sub> O <jats:sub>5</jats:sub> . A high mass loading and improved power capability were reached by tailoring the porosity in the holey graphene backbone with higher charge transport in the composite architecture. The interconnected graphene network provided excellent electron transport, and the hierarchical porous structure in the graphene sheets facilitated rapid ion transport and mitigated diffusion limitations. </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="6338" page="599" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aam5852">599</jats:related-article> </jats:p>

<jats:title>Tracing our ancestors in cave sediments</jats:title> <jats:p> Analysis of DNA from archaic hominids has illuminated human evolution. However, sites where thousand-year-old bones and other remains can be found are relatively rare. Slon <jats:italic>et al.</jats:italic> wanted to exploit any trace remains that our ancestors left behind. They looked for ancient DNA of hominids and other mammals in cave sediments, even those lacking skeletal remains. They identified mitochondrial DNA from Neandertal and Denisovan individuals in cave sediments at multiple sites. </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="6338" page="605" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aam9695">605</jats:related-article> </jats:p>

<jats:title>Shipping iron around in small packages</jats:title> <jats:p> Iron plays a crucial role in a wide variety of biological functions, which in turn rely on the proteins that transport the metal in and out of cells. Grillo <jats:italic>et al.</jats:italic> used a simple lipophilic small molecule that binds iron ions to restore transport in animal models with deficiencies in iron transporters. This cyclic ketol, hinokitiol, was first tested in yeast and then shown to promote gut iron absorption in rats and mice, as well as hemoglobin production in zebrafish. </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="6338" page="608" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aah3862">608</jats:related-article> </jats:p>

<jats:title>ER-PM contacts in nonclathrin endocytosis</jats:title> <jats:p> The epidermal growth factor receptor (EGFR) is internalized through both clathrin-mediated endocytosis and nonclathrin endocytosis (NCE). The two pathways act in concert to sustain EGFR signaling or its long-term attenuation. The mechanistic underpinnings of EGFR-NCE are unclear. Caldieri <jats:italic>et al.</jats:italic> used a variety of cell and molecular biology approaches to identify nine regulators of EGFR-NCE (see the Perspective by Tan and Anderson). They also identified an additional cargo of the pathway (CD147). One of the regulators of the pathway was the endoplasmic reticulum (ER)-resident protein reticulon 3 (RTN3). Unexpectedly, EGFR-NCE required the formation of specific contacts between the plasma membrane (PM) and the cortical ER, mediated by RTN3. ER-PM contact sites were required in the very early steps of the internalization process for the maturation of NCE tubular intermediates. </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="6338" page="617" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aah6152">617</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6338" page="584" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aan4807">584</jats:related-article> </jats:p>

<jats:title>Intricacy anchored by uranium</jats:title> <jats:p> Metal-organic frameworks generally have one level of assembly complexity: Organic linkers join inorganic nodes in a repeating lattice. Li <jats:italic>et al.</jats:italic> created a structure composed of cuboctahedra, assembled from uranium cations and organic linkers, that shared triangular faces to form prisms. These structures formed cages, which in turn joined to make tetrahedra that assembled with a diamond-lattice topology. This hierarchical open structure generated a huge unit cell with more than 800 nodes and linkers, containing internal cavities with diameters of 5 and 6 nm. </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="6338" page="624" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aam7851">624</jats:related-article> </jats:p>

<jats:title>How much water is in that exoplanet?</jats:title> <jats:p> Thousands of exoplanets have been identified, but little is known about their atmospheres, especially for bodies smaller than Jupiter. The extent and composition of an atmosphere can provide evidence for how an exoplanet formed. Wakeford <jats:italic>et al.</jats:italic> used the Hubble and Spitzer space telescopes to measure the spectrum of the atmosphere around HAT-P-26b, a Neptune-sized exoplanet discovered in 2011. They detected signatures of water and clouds; this allowed them to constrain the atmospheric composition, which appears not to have been altered substantially since it formed. </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="6338" page="628" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aah4668">628</jats:related-article> </jats:p>

<jats:title>Resolution achieved</jats:title> <jats:p> Chloroplasts possess multiple copies of their own chloroplast DNA that are packaged into DNA-protein complexes known as nucleoids. The shape, number, and distribution of chloroplast nucleoids change markedly depending on the cell cycle, developmental stage, and nutritional environment. Kobayashi <jats:italic>et al.</jats:italic> identified Holliday junction resolvase as a key factor in the dynamism of chloroplast nucleoids in the unicellular green algae <jats:italic>Chlamydomonas reinhardtii</jats:italic> . The gene encoding the resolvase is ubiquitously conserved among green plants. Disruption or down-regulation of this gene also disturbed chloroplast nucleoid organization and segregation in the land plant <jats:italic>Arabidopsis thaliana</jats:italic> . </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="6338" page="631" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aan0038">631</jats:related-article> </jats:p>

<jats:title>Mapping the world's dry forests</jats:title> <jats:p> The extent of forest area in dryland habitats, which occupy more than 40% of Earth's land surface, is uncertain compared with that in other biomes. Bastin <jats:italic>et al.</jats:italic> provide a global estimate of forest extent in drylands, calculated from high-resolution satellite images covering more than 200,000 plots. Forests in drylands are much more extensive than previously reported and cover a total area similar to that of tropical rainforests or boreal forests. This increases estimates of global forest cover by at least 9%, a finding that will be important in estimating the terrestrial carbon sink. </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="6338" page="635" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aam6527">635</jats:related-article> </jats:p>

<jats:title>Maximizing growth by sharing</jats:title> <jats:p> Bacterial colonies can undergo synchronized oscillations of cell growth, in which individual cells communicate through potassium ion-mediated electrical signals. Liu <jats:italic>et al.</jats:italic> found that such communication can also occur between adjacent colonies (see the Perspective by Gordon). Furthermore, colonies that would normally oscillate in synchrony adapted to an environment in which the nutrient supply was limited by growing out of phase with one another. Mathematical modeling and further experiments showed that this kept the colonies from having to compete for the limited nutrient and, counterintuitively, allowed the colonies to grow more quickly than they did with a higher nutrient concentration. </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="6338" page="638" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aah4204">638</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6338" page="583" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aan3886">583</jats:related-article> </jats:p>