Catálogo de publicaciones - revistas

<jats:title>Locust Heaven</jats:title> <jats:p> Locust outbreaks have severe consequences for agriculture, but the conditions that promote an outbreak are unknown. <jats:bold> Cease <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="467" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1214433">467</jats:related-article> ) investigated aspects of the locust diet and found that increased nitrogen content of cereal grasses reduced the size and viability of a herbivorous locust species. This locust prefers low N plants, which result from heavy grazing by livestock and erosion. </jats:p>

<jats:title>A Good Judge of Distance</jats:title> <jats:p> Jumping spiders actively pursue their prey, often jumping relatively long distances in order to catch them. Such feats require accurate depth perception. <jats:bold> Nagata <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="469" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1211667">469</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="6067" page="409" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1216887">Herberstein and Kemp</jats:related-article> </jats:bold> ) show that jumping spiders use a process called image defocus, which allows depth perception to be obtained through the comparison of a nonfocused image to a focused image within the same eye. A single layer within the spider's eye that could not focus green light nevertheless contained a green sensitive pigment. Thus, this layer always receives an unfocused image, while other layers receive images in focus. Confirming this eye arrangement's role in depth perception, spiders unlucky enough to be bathed in green light nearly always jumped short of their target. </jats:p>

<jats:title>Prion Problem</jats:title> <jats:p> Prion disease, like “mad cow disease,” has shown a frightening ability to cross the species transmission barrier, but, mercifully, with low efficiency. However, the role of different tissues in prion cross-species transmission is unclear. <jats:bold> Béringue <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="472" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1215659">472</jats:related-article> ; see the cover; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6067" page="411" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1218167">Collinge</jats:related-article> </jats:bold> ) compared the ability of brain and lymphoid tissues from “ovinized” (sheeplike) and “humanized” transgenic mouse models to replicate prion transmission across a robust transmission barrier. Lymphoid tissue of these mice was consistently more permissive than brain tissue to prions such as those causing chronic wasting disease and bovine spongiform encephalopathy. Because previous measures of the transmission barrier have focused on the brain, this heightened susceptibility of lymphoid tissues could strongly impact estimates of the number of silent carriers of prion disease. </jats:p>

<jats:title>Antigen Polarity in B Cell Differentiation</jats:title> <jats:p> Communication received through cell contact is critical for the differentiation of specialized effector cell populations during the immune response. For example, B lymphocytes acquire antigen that they present to helper T lymphocytes. T lymphocytes, in turn, provide key differentiation signals to B lymphocytes. In order to learn more about this process, <jats:bold> Thaunat <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="475" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1214100">475</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6067" page="408" related-article-type="in-this-issue" vol="335" xlink:href="10.1126/science.1218165"> <jats:bold>Dustin and Meyer-Hermann</jats:bold> </jats:related-article> ) used multiphoton microscopy and imaging flow cytometry to visualize the localization of antigen in B lymphocytes during an immune response. Antigen acquired by B lymphocytes exhibited a polarized distribution that was sustained over several rounds of cell division. This produced a population of activated B lymphocytes that contained very low levels of antigen. Daughter cells that received more antigen were better able to stimulate T cells. Because cues received through T lymphocyte interactions are likely to influence B lymphocyte fate decisions, unequal distribution of antigen in dividing B lymphocytes may influence their differentiation. </jats:p>

<jats:p>The show includes repeatability in natural selection, livestock grazing and locust outbreaks, new frontiers in supercomputing, and more.</jats:p>

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