Catálogo de publicaciones - revistas

<jats:title>Locust Wing Aerodynamics</jats:title> <jats:p> Insect wings function as deformable aerofoils, but the precise aerodynamic benefits of the observed deformations have remained obscure. Previous models have treated the wing as a flat plate, lacking any deformation, even though it is clear that the locust wing can twist and rotate along its length. <jats:bold> Young <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="1549" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175928">1549</jats:related-article> ) validate a computational fluid dynamic model, using particle imaging velocimetry and smoke visualization of the flow around actual locusts, and use the model to investigate the effect of measured changes in wing shape during a stroke cycle. The complexity of insect wing venation directly affects the aerodynamics of flight via the intermediary of wing deformation. </jats:p>

<jats:title> Anyone for <jats:sc>d</jats:sc> ? </jats:title> <jats:p> The chemistry of amino acids comes in two chirally distinct flavors—so-called <jats:sc>l</jats:sc> - and <jats:sc>d</jats:sc> -enantiomers. By far the most commonly used form of amino acids in all kingdoms of life is the <jats:sc>l</jats:sc> -form. Now <jats:bold> Lam <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="1552" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178123">1552</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="5947" page="1505" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1180332">Blanke</jats:related-article> </jats:bold> ) present the unanticipated observation that diverse bacteria release large amounts of various <jats:sc>d</jats:sc> -amino acids into the environment in a population density–dependent fashion and that <jats:sc>d</jats:sc> -amino acids act as extracellular effectors that regulate the composition, structure, amount, and strength of peptidoglycan, the major stress-bearing component of the bacterial cell wall. </jats:p>

<jats:title>Desperately Seeking Glucose</jats:title> <jats:p> Mutations in oncogenes and tumor suppressor genes allow cancer cells to outgrow their neighboring healthy cells. What microenvironmental conditions provide a selective growth advantage to these cells? <jats:bold> Yun <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="1555" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1174229">1555</jats:related-article> , published online 6 August) identify low glucose availability as a microenvironmental factor driving the acquisition of <jats:italic>KRAS</jats:italic> oncogenic mutations that allow cancer cells to survive and grow. In genetically matched colorectal cancer cells that differed only in the mutational status of the <jats:italic>KRAS</jats:italic> oncogene, mutant cells selectively overexpressed glucose transporter-1 and exhibited enhanced glucose uptake and glycolysis. When cells with wild-type <jats:italic>KRAS</jats:italic> were placed in a low-glucose environment, very few cells survived but most of the survivors expressed high levels of glucose transporter-1, and a small percentage of the survivors had acquired new <jats:italic>KRAS</jats:italic> mutations. Thus, glucose deprivation may help to drive the acquisition of cell growth–promoting oncogenic mutations during tumor development. </jats:p>

<jats:p>When it comes to monitoring biological interactions, whether of nucleic acids, proteins,small molecules, or cells, labels are essential for detection, right? Researchers certainly have embraced detection modalities based on tagging with radioisotopes, fluorescent dyes, and conjugated enzymes. Yet in many cases such molecular baggage is unnecessary, and possibly detrimental. But there is another way. Whether based on optical, mechanical, or electrical detection, label-free methods can probe molecular pas de deux in their native, unadulterated states. As a result, they are faster, simpler, and more physiological than their labeled counterparts.</jats:p>

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

<jats:p>The show includes the link between public opinion and international terrorism, locust wing aerodynamics, companion-animal sterilization, and more.</jats:p>