Catálogo de publicaciones - revistas

<jats:title>Community changes centuries in the making</jats:title> <jats:p> How might climate change affect the base of the marine food chain? Phytoplankton, the foundation of the marine ecosystem, depend on ambient oceanographic conditions such as temperature, salinity, and nutrient availability, which affect ocean chemistry and isotopic distributions. McMahon <jats:italic>et al.</jats:italic> report carbon isotopic composition changes in the North Pacific Ocean over the past 1000 years, which reflect changes in the community composition of phytoplankton in the region (see the Perspective by Vogt). An ongoing trend toward greater prevalence of nitrogen-fixing cyanobacteria that began 100 years ago might lead to a more efficient carbon pump and remove increasing amounts of CO <jats:sub>2</jats:sub> from the atmosphere. </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="6267" page="1530" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aaa9942">1530</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6267" page="1466" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad6946">1466</jats:related-article> </jats:p>

<jats:title>Passing an acid test</jats:title> <jats:p> Calcifying marine organisms will generally find it harder to make and maintain their carbonate skeletons as increasing concentrations of atmospheric CO <jats:sub>2</jats:sub> acidify the oceans. Nevertheless, some types of organisms will be damaged more than others, and some may even benefit from higher CO <jats:sub>2</jats:sub> levels. Coccolithophores are a case in point, because their photosynthetic ability is strongly carbon-limited. Rivero-Calle <jats:italic>et al.</jats:italic> show that the abundance of coccolithophores in the North Atlantic has increased by up to 20% or more in the past 50 years (see the Perspective by Vogt). Thus, this major phytoplankton functional group may be able to adapt to a future with higher CO <jats:sub>2</jats:sub> concentrations. </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="6267" page="1533" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aaa8026">1533</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6267" page="1466" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad6946">1466</jats:related-article> </jats:p>

<jats:title>East joins West to complete a picture</jats:title> <jats:p> How have eastern equatorial Pacific sea surface temperatures varied over the past 1000 years? Today, the tropical Pacific Ocean has a large influence on global climate, through processes such as El Niño. Researchers would thus like to know how the ocean varied in the past. Although good records exist from the western ocean, the same has not been true for the eastern side. Rustic <jats:italic>et al.</jats:italic> analyzed marine sediments recovered from near the Galapagos Islands. They conclude that the tropical Pacific Ocean changed state about 500 years ago, near the transition between the warm Medieval Climate Anomaly and the cold Little Ice Age. </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="6267" page="1537" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac9937">1537</jats:related-article> </jats:p>

<jats:title>Sulfate reduction via a trisulfide</jats:title> <jats:p> Microorganisms can respire sulfur compounds in the absence of oxygen, eventually leading to the production of hydrogen sulfide. This ancient metabolism is common in modern anoxic environments, but the enzymatic pathways aren't yet fully resolved. Through in vivo and in vitro experiments, Santos <jats:italic>et al.</jats:italic> clarify the enzymology of the sulfate reduction pathway in both bacteria and archaea (see the Perspective by Fritz and Kroneck). Reduction of the sulfite intermediate results in the linkage of two cysteine residues to a third sulfur atom from sulfite, forming a trisulfide product. Because the reduction of sulfite conveys a strong isotopic signature on sulfur in the environment, isotope fractionation models should account for this additional step. </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="6267" page="1541" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad3558">1541</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6267" page="1476" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad8139">1476</jats:related-article> </jats:p>

<jats:title>Red tides make dinner hard to find</jats:title> <jats:p> Domoic acid (DA) is a neurotoxin produced by marine algae. When present in large amounts, it is harmful to marine organisms and to humans. Cook <jats:italic>et al.</jats:italic> tested California sea lions being treated at a marine mammal rescue facility. Animals that had evidence of exposure to DA had lesions in their hippocampus and displayed reduced performance on spatial memory tasks. Because such tasks are essential to foraging in a marine environment, increasing exposure to DA may be contributing to increasing sea lion strandings. </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="6267" page="1545" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac5675">1545</jats:related-article> </jats:p>

<jats:title>ESCRTs work in two very different ways</jats:title> <jats:p> The so-called ESCRT proteins are involved in the budding of vesicles into the lumen of endosomes and in virus budding. These reactions involve the formation of a cytoplasm-filled neck that spirals of the ESCRTs help to seal. McCullough <jats:italic>et al.</jats:italic> now show that ESCRTs can also promote the scission of membrane tubules with the completely opposite topology. ESCRT-III and IST1 ESCRT subunits form spirals on the outside of membrane tubules and so can mediate the budding of tubules and vesicles into the cytosol. Relatively minor structural rearrangements were required to turn ESCRT function on its head. </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="6267" page="1548" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aad8305">1548</jats:related-article> </jats:p>

<jats:title>Essential genes and species incompatibilities</jats:title> <jats:p> Crosses between two fruit fly species, <jats:italic>Drosophila melanogaster</jats:italic> and <jats:italic>D. simulans</jats:italic> , result in hybrid progeny that are all female. Although some of the genes responsible for this species barrier are known, the full complement of molecular determinants that lead to inviable males has remained mysterious. Phadnis <jats:italic>et al.</jats:italic> used mutagenesis and a sequencing-based genomic screen to link hybrid inviability to the cell cycle. The inviable males result from an interaction between three genes, one of which is essential, which precluded its identification with standard genetic screens. This strategy to identify speciation genes can be applied to other model and nonmodel systems. </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="6267" page="1552" related-article-type="in-this-issue" vol="350" xlink:href="10.1126/science.aac7504">1552</jats:related-article> </jats:p>

<jats:p>On this week's show: Our breakthrough of the year and this year's top news stories</jats:p>

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