Catálogo de publicaciones - revistas

<jats:title>Oxidizing hydrogen in place of nitrite</jats:title> <jats:p> Microorganisms are important drivers of Earth's nitrogen cycle. Many of the organisms responsible for mediating the reactions of one phase of nitrogen to another are thought to be ecologic specialists. Using a combination of genomic and experimental analyses, Koch <jats:italic>et al.</jats:italic> show that <jats:italic>Nitrospira moscoviensis</jats:italic> , a member of a widely distributed genus of nitrite-oxidizing bacteria, can oxidize hydrogen instead of nitrite to support growth when oxygen is present. Not only does this ecologic flexibility suggest a broader distribution of these organisms in natural settings, but they may be important in engineered environments as well. </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="6200" page="1052" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256985">1052</jats:related-article> </jats:p>

<jats:title>Brain stimulation to improve human memory</jats:title> <jats:p> The hippocampus is a crucial brain area for certain types of memory. Working with humans, Wang <jats:italic>et al.</jats:italic> found that a specific type of non-invasive brain stimulation improved memory tests and enhanced information flow between the hippocampus and a number of other brain regions. This increased connectivity was highly specific for the individual target areas selected for each participant. </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="6200" page="1054" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1252900">1054</jats:related-article> </jats:p>

<jats:title>T and B cells' intricate molecular dance</jats:title> <jats:p> Generating high-affinity antibodies to fight infection is no easy task. To do so requires multiple steps, including T cells interacting with antibody-producing B cells in lymph nodes. These interactions select B cells expressing high-affinity antibodies for further proliferation, ensuring that the immune response generates high-affinity antibodies in large quantities. Shulman <jats:italic>et al.</jats:italic> use fluorescent live-cell imaging in mice to determine the molecular details of these interactions. They find that T cells engage B cells in short-lived mobile contacts during selection. These contacts cause T cells to flux calcium and produce proteins called cytokines, which probably drive B cells to proliferate and produce high-affinity antibodies. </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="6200" page="1058" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1257861">1058</jats:related-article> </jats:p>

<jats:title>Push me, pull you, that's the way to move</jats:title> <jats:p> Primary cells, derived directly from human tissue, exhibit different behaviors in shape and signaling within three-dimensional (3D) or 2D spaces. When the pressure within the cell increases, cells display limb-like bumps, which they use to move through their 3D environment. Petrie <jats:italic>et al.</jats:italic> now show that when the complex of actin and myosin contracts, it controls the pressure within cells and therefore the shape of those protruding structures (see the Perspective by DeSimone and Horwitz). The authors measured internal pressures in migrating mammalian cells. In the 3D matrix, those cells have higher pressure that differs between the front and back of the cell, which creates a piston effect. </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="6200" page="1062" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256965">1062</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6200" page="1002" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1259176">1002</jats:related-article> </jats:p>

<jats:title>Chromatin mutations disrupt development</jats:title> <jats:p> Histone proteins form the core packaging material for our genomic DNA, and covalent modifications to amino acid residues in their structure play an important role in the epigenetic control of gene expression. Herz <jats:italic>et al.</jats:italic> show that specific mutations in the residues that are normally modified to regulate expression cause severe disruption of normal development in the fruit fly. Similar mutations are known to be involved in a subtype of aggressive pediatric brain cancers. Insights into the epigenetic regulatory pathways disrupted by these mutations in <jats:italic>Drosophila</jats:italic> may suggest possible treatments for human cancers. </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="6200" page="1065" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255104">1065</jats:related-article> </jats:p>

<jats:title>Activating a receptor to excite a neuron</jats:title> <jats:p> Transmitting signals between nerve cells, occuring at structures known as synapses, is critical to processes such as learning and memory. Fast transmission occurs when glutamate is released from a presynaptic neuron and binds to ionotropic glutamate receptors (iGluRs) in the cell membrane of a postsynaptic neuron. The iGluR contains an ion channel that is transiently opened, to activate the postsynaptic neuron, but then closes rapidly. Chen <jats:italic>et al.</jats:italic> and Yelshanskaya <jats:italic>et al.</jats:italic> report crystal structures in a range of conformations that together provide insight into how glutamate binding causes the channel to open and how other molecules that bind to the receptor modulate this. The information could aid in the design of drugs to treat cognitive impairment or seizure disorders </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="6200" page="1021" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1258409">1021</jats:related-article> and p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6200" page="1070" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256508">1070</jats:related-article> </jats:p>

<jats:title>Rabbits softly swept to domestication</jats:title> <jats:p> When people domesticate animals, they select for tameness and tolerance of humans. What else do they look for? To identify the selective pressures that led to rabbit domestication, Carneiro <jats:italic>et al.</jats:italic> sequenced a domestic rabbit genome and compared it to that of its wild brethren (see the Perspective by Lohmueller). Domestication did not involve a single gene changing, but rather many gene alleles changing in frequency between tame and domestic rabbits, known as a soft selective sweep. Many of these alleles have changes that may affect brain development, supporting the idea that tameness involves changes at multiple loci. </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="6200" page="1074" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1253714">1074</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6200" page="1000" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1258775">1000</jats:related-article> </jats:p>

<jats:p>On this week's show: Our microbial housemates and a news roundup.</jats:p>

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