Catálogo de publicaciones - revistas

<jats:p>Membrane lipids must be metabolized to protect plants from frost.</jats:p>

<jats:p>Parasites interact in complex ways in the voles they infect.</jats:p>

<jats:p>Inorganic nanoparticles coated with organic films can display surface chemistries that allow them to function like globular proteins.</jats:p>

<jats:p>Genetically engineered corn plants can reduce pest damage on neighboring, unmodified plants.</jats:p>

<jats:title>Nitrogen's Past and Future</jats:title> <jats:p> Microorganisms have been controlling Earth's nitrogen cycle since life originated. With life evolving around it, nitrogen became both an essential nutrient and a major regulator of climate. <jats:bold> Canfield <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="192" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1186120">192</jats:related-article> ) review the major changes in the nitrogen cycle throughout Earth's history. Most of the time, perturbations typically coincided with the evolution of new metabolic pathways in various Bacteria or Archaea. The last century, however, has seen humans push the biological nitrogen cycle into a new stage altogether. The addition of large quantities of fixed nitrogen to crops in the form of fertilizer chokes out aquatic life that relies on runoff and adds significant amounts of N <jats:sub>2</jats:sub> O—a potent greenhouse gas—to the atmosphere. Although microorganisms may one day restore balance to the nitrogen cycle that they helped shape for billions of years, humans must modify their behavior or risk causing irreversible changes to life on Earth. </jats:p>

<jats:p>A searchable database of images allows detailed analysis of bacterial motility.</jats:p>

<jats:p>A mechanism for the protective effects of tau reduction in mouse models of Alzheimer’s disease.</jats:p>

<jats:title>Feeling the Pinch</jats:title> <jats:p> Nanoparticles exhibit many different properties compared to their larger counterparts, but how the stability of certain phases relative to others is affected by a change in particle size is often unclear. Using a thermodynamic probe sensitive to nanoparticle surfaces, <jats:bold> Navrotsky <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="199" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1195875">199</jats:related-article> ) show that surface energy strongly influences the stability of some metal oxides relative to others. For example, nanoparticles of CoO, which are stable at larger sizes, are only stable over a very narrow range of conditions due their high surface energies. Cobalt oxides are catalysts that may one day promote the cost-effective generation of hydrogen from water, but nanoparticles in soils and biological systems—including iron and manganese oxides—also feel the pinch of surface energy on their range of stability. </jats:p>

<jats:title>Diving into Deep Water</jats:title> <jats:p> The Deepwater Horizon oil spill in the Gulf of Mexico was one of the largest oil spills on record. Its setting at the bottom of the sea floor posed an unanticipated risk as substantial amounts of hydrocarbons leaked into the deepwater column. Three separate cruises identified and sampled deep underwater hydrocarbon plumes that existed in May and June, 2010—before the well head was ultimately sealed. <jats:bold> Camilli <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="201" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1195223">201</jats:related-article> ; published online 19 August) used an automated underwater vehicle to assess the dimensions of a stabilized, diffuse underwater plume of oil that was 22 miles long and estimated the daily quantity of oil released from the well, based on the concentration and dimensions of the plume. <jats:bold> Hazen <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="204" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1195979">204</jats:related-article> ; published online 26 August) also observed an underwater plume at the same depth and found that hydrocarbon-degrading bacteria were enriched in the plume and were breaking down some parts of the oil. Finally, <jats:bold> Valentine <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="208" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1196830">208</jats:related-article> ; published online 16 September) found that natural gas, including propane and ethane, were also present in hydrocarbon plumes. These gases were broken down quickly by bacteria, but primed the system for biodegradation of larger hydrocarbons, including those comprising the leaking crude oil. Differences were observed in dissolved oxygen levels in the plumes (a proxy for bacterial respiration), which may reflect differences in the location of sampling or the aging of the plumes. </jats:p>

<jats:title>Diving into Deep Water</jats:title> <jats:p> The Deepwater Horizon oil spill in the Gulf of Mexico was one of the largest oil spills on record. Its setting at the bottom of the sea floor posed an unanticipated risk as substantial amounts of hydrocarbons leaked into the deepwater column. Three separate cruises identified and sampled deep underwater hydrocarbon plumes that existed in May and June, 2010—before the well head was ultimately sealed. <jats:bold> Camilli <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="201" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1195223">201</jats:related-article> ; published online 19 August) used an automated underwater vehicle to assess the dimensions of a stabilized, diffuse underwater plume of oil that was 22 miles long and estimated the daily quantity of oil released from the well, based on the concentration and dimensions of the plume. <jats:bold> Hazen <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="204" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1195979">204</jats:related-article> ; published online 26 August) also observed an underwater plume at the same depth and found that hydrocarbon-degrading bacteria were enriched in the plume and were breaking down some parts of the oil. Finally, <jats:bold> Valentine <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="208" related-article-type="in-this-issue" vol="330" xlink:href="10.1126/science.1196830">208</jats:related-article> ; published online 16 September) found that natural gas, including propane and ethane, were also present in hydrocarbon plumes. These gases were broken down quickly by bacteria, but primed the system for biodegradation of larger hydrocarbons, including those comprising the leaking crude oil. Differences were observed in dissolved oxygen levels in the plumes (a proxy for bacterial respiration), which may reflect differences in the location of sampling or the aging of the plumes. </jats:p>