Catálogo de publicaciones - revistas

<jats:title>They Walked Together</jats:title> <jats:p> Paisley Cave in Oregon provides some of the earliest evidence for humans in North America. <jats:bold> Jenkins <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="223" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1218443">223</jats:related-article> ) provide a wide variety of additional evidence of early human occupation of this site, including a series of radiocarbon ages extending back to nearly 12,500 radiocarbon years ago (about 14,500 calendar years ago). The find includes examples of projectile points representative of the Western Stemmed Tradition dating to about 11,100 radiocarbon years ago. The Western Stemmed Tradition has been thought to have evolved after the dominant Clovis technology, but the find suggests that the two cultures overlapped in time. </jats:p>

<jats:title>Growing Extinction Debt</jats:title> <jats:p> Predicting, and potentially preventing, extinction is a central goal of conservation biology. <jats:bold> Wearn <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="228" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219013">228</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="6091" page="162" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1224819">Rangel</jats:related-article> </jats:bold> ) describe a mathematical approach for predicting the time lags in extinction following habitat loss. The model was applied to the highly biodiverse Brazilian Amazon region, and used to reconstruct the spatial and temporal patterns of extinction and the accumulation of extinction debt from 1970 through to the present, and to extrapolate to 2050 under four deforestation scenarios. The Amazon basin sits at a critical point: Few species have been driven extinct to date, but an extinction debt is rapidly accumulating, which could lead to an increasing rate of extinction in the next four decades. </jats:p>

<jats:title>GPCR Close-Up</jats:title> <jats:p> Structures of G protein–coupled receptors (GPCRs) determined in the past few years, have provided insight into the function of this important family of membrane proteins. <jats:bold> Liu <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="232" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219218">232</jats:related-article> ) used a protein-engineering strategy to produce a stabilized version of the human A <jats:sub>2A</jats:sub> adenosine receptor (A <jats:sub>2A</jats:sub> AR). The high-resolution structure reveals the position of about 60 internal waters, which suggests an almost continuous channel in the GPCR and can explain the allosteric effects of Na <jats:sup>+</jats:sup> on ligand binding and how cholesterol may contribute to GPCR stabilization. </jats:p>

<jats:title>Biofilms Up Close</jats:title> <jats:p> Many bacterial infections involve biofilm formation. Cells within a biofilm are significantly more resistant to immune clearance and antibiotics compared to unattached, planktonic cells. <jats:bold> Berk <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="236" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1222981">236</jats:related-article> ) applied superresolution optical methods to image living bacteria with nanometer-scale precision as they form a biofilm. <jats:italic>Vibrio cholerae</jats:italic> biofilms were observed to have three distinct levels of spatial organization: cells, clusters of cells, and collections of clusters. Each cell cluster was wrapped in a flexible, elastic envelope. Several <jats:italic>V. cholerae</jats:italic> matrix proteins played complementary architectural roles during biofilm development. RbmA provided cell-cell adhesion, Bap1 allowed the developing biofilm to adhere to surfaces, and heterogeneous mixtures of VPS, RbmC, and Bap1 formed the dynamic, flexible, and ordered envelopes that encase the cell clusters. </jats:p>

<jats:title>Pole to Pole</jats:title> <jats:p> How do fission yeast cells decide when to grow at a single end (or pole) of the cell or whether to grow in a multipolar manner? <jats:bold> Das <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="239" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1218377">239</jats:related-article> , published online 17 May) found that accumulation of the active form of the small guanine nucleotide–binding protein Cdc42 at the growing tip of the cell oscillated with a period of a few minutes. In cells growing at one pole, the oscillations were primarily present at that pole and during bipolar growth symmetrical anticorrelated oscillations were observed. Dynamic competition for Cdc42 between multiple growth zones could represent a flexible mechanism to modulate cell growth asymmetry. </jats:p>

<jats:title>MMS19 Joins the CIA</jats:title> <jats:p> Iron-sulfur (Fe-S) proteins play a critical role in cell metabolism and particularly in DNA repair and replication. Mutants in eukaryotic gene <jats:italic>MMS19</jats:italic> are particularly sensitive to DNA damaging agents, suggesting that it is involved in DNA repair, but the mutations can also have other wide-ranging effects on the cell (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6091" page="160" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1225852">Gottschling</jats:related-article> </jats:bold> ). Now, <jats:bold> Stehling <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="195" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219723">195</jats:related-article> , published online 7 June) and <jats:bold> Gari <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="243" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219664">243</jats:related-article> , published online 7 June) show that in both yeast and humans, MMS19 functions as part of the cytosolic Fe-S protein assembly (CIA) machinery. The MMS19 is part of a specialized CIA targeting complex that plays a role late in cytosolic Fe-S protein assembly to direct Fe-S cluster transfer from the CIA scaffold complex to a subset of Fe-S proteins, including a number associated with DNA metabolism. </jats:p>

<jats:p>The show includes a vaccine that recombines in the wild, early North American inhabitants, HIV/AIDS in the U.S., 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>