Catálogo de publicaciones - revistas

<jats:p>Small peptides encoded by a so-called long noncoding RNA play an active role in regulating gene expression.</jats:p>

<jats:p>First-principles design and directed evolution expand the role of enzymes in chemical synthesis.</jats:p>

<jats:p>Can consumers and businesses benefit from socially responsible pricing?</jats:p>

<jats:p>Our understanding of a major methane sink is based on studies of quiescent sediments and dynamic seeps. But do the same processes operate in both environments?</jats:p>

<jats:p>Near the end of the last ice age, the Pacific appears to have played a bigger role in forming deep ocean waters than it does today.</jats:p>

<jats:p>Effective strategies to treat sickle cell disease could involve manipulating the type of hemoglobin produced in patients.</jats:p>

<jats:p> Deletions and insertions affect chromosome segregation in the worm <jats:italic>Caenorhabditis elegans</jats:italic> . </jats:p>

<jats:title>Golden Regulator</jats:title> <jats:p> <jats:italic>Staphylococcus aureus</jats:italic> is a common cause of intractable infections that are exacerbated by an array of toxins and virulence factors. The <jats:italic>agr</jats:italic> pheromone has been thought to represent the master regulator of virulence in this pathogen, but it is not always expressed and is also found in many nonpathogenic cocci. A strictly conserved, nonribosomal peptide synthetase has now been found by <jats:bold> Wyatt <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="294" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1188888">294</jats:related-article> , published online 3 June) by genome mining. The enzyme assembles valine and tyrosine into cyclic dipeptides called aureusimines that are expressed by all sequenced strains of <jats:italic>S. aureus</jats:italic> , including the “superbug” MRSA (Methicillin-resistant <jats:italic>Staphylococcus aureus</jats:italic> ). Microarray analysis showed a striking effect of mutation in the synthetase locus on the production of immunomodulators, hemolysins, and other exotoxins by the pathogen. Indeed, mice infected systemically with the mutant strain showed a restricted spread of infection compared with the wild type. </jats:p>

<jats:title>Observing the Magnon Hall Effect</jats:title> <jats:p> The anomalous thermal Hall effect occurs when transverse heat transport is generated in the absence of an external magnetic field. The transport may be mediated by free carriers, phonons, or spin waves (magnons). <jats:bold> Onose <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="297" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1188260">297</jats:related-article> ) observed this effect in an insulating ferromagnet and were able to rule out free carriers and phonons as the mediators of the thermal transport. Instead, the observations are consistent with a theory ascribing its origin to magnon propagation. This thermal magnon Hall effect is caused by the spin-orbit interaction, which acts in a fashion similar to the magnetic field in the conventional Hall effect. Its observation in an insulator may enable the elimination of losses in spintronic applications. </jats:p>

<jats:title>Snapshot of a Strained Ring</jats:title> <jats:p> Benzene and cyclobutadiene possess diametrically opposed properties. The former, a hexagonal hydrocarbon with a geometry perfectly suited to its bonding arrangement, exhibits unusual stability. The latter, with its two fewer carbons tightly squeezed into the right angles of a 4-membered ring, rapidly forms a dimer to relieve its considerable geometric and electronic strain. Monomeric cyclobutadiene was first isolated in substantial quantity by confining it within a molecular shell, but it has eluded full structural characterization. <jats:bold> Legrand <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="299" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1188002">299</jats:related-article> ) have now found a host lattice that stabilizes a dimethyl-substituted derivative of the molecule sufficiently to allow analysis of its structure and bonding motif by x-ray diffraction. </jats:p>