Catálogo de publicaciones - revistas

<jats:title>Locomotion-related signals in the brain</jats:title> <jats:p> To calculate where we are in space, continuous knowledge of one’ s speed is necessary. How does the brain know how fast the body is traveling during locomotion? Using in vivo calcium imaging, electrophysiology, optogenetics, cell tracing, and histology, Farrell <jats:italic>et al</jats:italic> . identified neurons in the rodent supramammillary nucleus of the hypothalamus that encode future locomotor speed and potently drive locomotion when stimulated. Because these locomotor neurons have extensive axons in brain areas that support spatial navigation, this cell type distributes this information selectively to areas that require knowledge of speed. This nucleus is functionally positioned between input from a higher-order cognitive center and the downstream midbrain where locomotor nuclei reside. —PRS </jats:p>

<jats:title>Dangerous terrain</jats:title> <jats:p> As climate change leads to regions of the world becoming increasingly uninhabitable, unregulated human migration is likely to increase. Migrants often traverse dangerous terrain, and the environmental conditions they encounter when exposed can be deadly. Campbell-Staton <jats:italic>et al</jats:italic> . used an approach commonly used to predict spatially explicit regions of physiological challenge in animal species to create a hazard landscape for the border crossing between the United States and Mexico. Their predictions of high risk, particularly due to dehydration, coincided with regions of high migrant mortality. Such detailed predictions may help to prevent these tragedies. —SNV </jats:p>

<jats:title>A passive turnoff</jats:title> <jats:p> Passive radiative cooling technology uses the infrared atmospheric window to allow outer space to be a cold sink for heat. However, this effect is one that is only helpful for energy savings in the warmer months. Wang <jats:italic>et al</jats:italic> . and Tang <jats:italic>et al</jats:italic> . used the metal-insulator transition in tungsten-doped vanadium dioxide to create window glass and a rooftop coating that circumvents this problem by turning off the radiative cooling at lower temperatures. Because the transition is simply temperature dependent, this effect also happens passively. Model simulations suggest that these materials would lead to energy savings year-round across most of the climate zones in the United States. —BG </jats:p>

<jats:title>A passive turnoff</jats:title> <jats:p> Passive radiative cooling technology uses the infrared atmospheric window to allow outer space to be a cold sink for heat. However, this effect is one that is only helpful for energy savings in the warmer months. Wang <jats:italic>et al</jats:italic> . and Tang <jats:italic>et al</jats:italic> . used the metal-insulator transition in tungsten-doped vanadium dioxide to create window glass and a rooftop coating that circumvents this problem by turning off the radiative cooling at lower temperatures. Because the transition is simply temperature dependent, this effect also happens passively. Model simulations suggest that these materials would lead to energy savings year-round across most of the climate zones in the United States. —BG </jats:p>

<jats:title>Reading amino acids by nanopore</jats:title> <jats:p> Nanopore technology enables sensing of minute chemical changes at the single-molecule level by detecting differences in an ion current as molecules are drawn through a membrane-embedded pore. The sensitivity is sufficient to discriminate between nucleotide bases in nanopore sequencing, and other applications of this technology are promising. Brinkerhoff <jats:italic>et al</jats:italic> . developed a nanopore-based, single-molecule approach in which a protein was sequentially scanned in single-amino-acid steps through the narrow construction of a nanopore, and ion currents were monitored to resolve differences in the amino acid sequence along the peptide backbone (see the Perspective by Bošković and Keyser). The peptide reader was capable of reliably detecting single-amino-acid substitutions within individual peptides. An individual protein could be re-read many times, yielding very high read accuracy in variant identification. These proof-of-concept nanopore experiments constitute a promising basis for the development of a single-molecule protein sequencer. —DJ </jats:p>

<jats:title>An experimental forest ecosystem drought</jats:title> <jats:p> Drought is affecting many of the world’ s forested ecosystems, but it has proved challenging to develop an ecosystem-level mechanistic understanding of the ways that drought affects carbon and water fluxes through forest ecosystems. Werner <jats:italic>et al</jats:italic> . used an experimental approach by imposing an artificial drought on an entire enclosed ecosystem: the Biosphere 2 Tropical Rainforest in Arizona (see the Perspective by Eisenhauer and Weigelt). The authors show that ecosystem-scale plant responses to drought depend on distinct plant functional groups, differing in their water-use strategies and their position in the forest canopy. The balance of these plant functional groups drives changes in carbon and water fluxes, as well as the release of volatile organic compounds into the atmosphere. —AMS </jats:p>

<jats:title>Early marine giant</jats:title> <jats:p> The largest animals to have ever lived occupied the marine environment. Modern cetaceans evolved their large size over tens of millions of years in response to the increased productivity of cold marine waters. However, whales were not the first marine giants to evolve. Sander <jats:italic>et al</jats:italic> . describe a 244-million-year-old fossil ichthyosaur that would have rivaled modern cetaceans in size (see the Perspective by Delsett and Pyenson). The animal existed at most 8 million years after the emergence of the first ichthyosaurs, suggesting a much more rapid size expansion that may have been fueled by processes after the Permian mass extinction. —SNV </jats:p>

<jats:title>Root meristem controls</jats:title> <jats:p> The plant meristem, a small cluster of stem cells generates all of the cell types necessary for the plant’s indeterminate growth pattern. Roszak <jats:italic>et al</jats:italic> . use single-cell analyses to follow development from the stem cell to the enucleated cell of the phloem vasculature. In the root of the small mustard plant <jats:italic>Arabidopsis</jats:italic> , this process takes just over 3 days, and the developmental trajectory spans more than a dozen different cell states. A transcriptional program initially held under repressive control is released as those initial repressors dissipate. Reciprocal repression by regulators early and late in the developmental trajectory control a rapid switch in the differentiation program. —PJH </jats:p>

<jats:title>Fibrin gums up the works</jats:title> <jats:p> Plasmin is an abundant plasma protease that cleaves and deactivates the clot-associated protein fibrin. Human deficiencies in plasmin and its inactive proenzyme form, plasminogen (PLG), cause severe inflammation in mucosal tissues such as the mouth and eyes. Silva <jats:italic>et al</jats:italic> . report that, like humans, mice lacking plasminogen accumulate extravascular fibrin and develop an oral pathology that phenocopies human ligneous periodontitis (see the Perspective by Vicanolo and Hidalgo). The excess fibrin activates neutrophils through the αMβ2 (Mac-1) integrin receptor, which triggers the production of reactive oxygen species and neutrophil extracellular traps. Additionally, certain human polymorphisms in the PLG gene were found to be associated with increased likelihood of developing periodontitis, suggesting that fibrin–neutrophil interactions may be an attractive target for future treatments of this prevalent disease. —STS </jats:p>