Catálogo de publicaciones - revistas

<jats:title>Computational analysis of cell walls</jats:title> <jats:p> Layers of intertwined fibers make up plant cell walls. The various types of fibers respond differently to deformation. Cellulose microfibrils, for example, can stretch or curve, changing their end-to-end length, and can also slide past each other, reorient relative directions, and bundle with neighboring microfibrils. Zhang <jats:italic>et al.</jats:italic> developed a computational model based on observations of onion skin epidermis that describes how these complex changes in space govern cell wall mechanics. The results inform ways to engineer multifunctional fibrous materials. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="706" related-article-type="in-this-issue" vol="372">706</jats:related-article> </jats:p>

<jats:title>Cleaning in a flash</jats:title> <jats:p> Hydroxyl radicals (OH) are the most important oxidizing species in the atmosphere and provide much of its ability to cleanse itself. It is known that nitric oxide production by lightning leads to the formation of OH and other atmospheric oxidants, such as ozone and hydroperoxyl radicals (HO <jats:sub>2</jats:sub> ), through a variety of chemical reactions. Brune <jats:italic>et al.</jats:italic> used airborne measurements of OH and HO <jats:sub>2</jats:sub> to show that lightning also produces them directly and in amounts much greater than expected. They found that this mechanism may be responsible for as much as one-sixth of the oxidizing capacity of Earth's atmosphere. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="711" related-article-type="in-this-issue" vol="372">711</jats:related-article> </jats:p>

<jats:title>Metabolic pathway regulates cell fate</jats:title> <jats:p> Lineage-specific regulators direct cell fate decisions, but the precise mechanisms are not well known. Using an in vivo chemical suppressor screen of a bloodless zebrafish mutant, Rossmann <jats:italic>et al.</jats:italic> show that the lineage-specific chromatin factor <jats:italic>tif1γ</jats:italic> directly regulates mitochondrial genes to drive red blood cell differentiation. Loss of <jats:italic>tif1γ</jats:italic> reduces coenzyme Q synthesis and function, impeding mitochondrial respiration and leading to epigenetic alterations and repression of erythropoiesis. The loss of blood in the mutant fish can be rescued by the addition of coenzyme Q. This work establishes a mechanism by which a chromatin factor tunes a metabolic pathway in a tissue-specific manner. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="716" related-article-type="in-this-issue" vol="372">716</jats:related-article> </jats:p>

<jats:title>Controlling interfacial superconductivity</jats:title> <jats:p> The interface between the oxides LaAlO <jats:sub>3</jats:sub> and KTaO <jats:sub>3</jats:sub> (111) has been shown to superconduct at temperatures up to 2 Kelvin. Chen <jats:italic>et al.</jats:italic> show that this superconductivity can be controlled with electric fields. As they tuned the gating voltage, the researchers observed a dome-shaped variation of the superconducting critical temperature. This variation could not be ascribed to the change in carrier density, but rather seemed to reflect the change in the mobility of the carriers. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="721" related-article-type="in-this-issue" vol="372">721</jats:related-article> </jats:p>

<jats:title>Genomics of radiation-induced damage</jats:title> <jats:p> The potential adverse effects of exposures to radioactivity from nuclear accidents can include acute consequences such as radiation sickness, as well as long-term sequelae such as increased risk of cancer. There have been a few studies examining transgenerational risks of radiation exposure but the results have been inconclusive. Morton <jats:italic>et al.</jats:italic> analyzed papillary thyroid tumors, normal thyroid tissue, and blood from hundreds of survivors of the Chernobyl nuclear accident and compared them against those of unexposed patients. The findings offer insight into the process of radiation-induced carcinogenesis and characteristic patterns of DNA damage associated with environmental radiation exposure. In a separate study, Yeager <jats:italic>et al.</jats:italic> analyzed the genomes of 130 children and parents from families in which one or both parents had experienced gonadal radiation exposure related to the Chernobyl accident and the children were conceived between 1987 and 2002. Reassuringly, the authors did not find an increase in new germline mutations in this population. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.abg2538">eabg2538</jats:related-article> , p. <jats:related-article issue="6543" page="725" related-article-type="in-this-issue" vol="372">725</jats:related-article> </jats:p>

<jats:title>What makes things twist?</jats:title> <jats:p> Crystallization and chirality have been entangled since Pasteur's observations on chiral tartaric acid crystals, yet there is still limited understanding of how chiral compounds form chiral crystal morphologies. For example, although a chiral seed crystal can promote a particular handedness, it is not clear why such seeds do not do so with 100% efficiency. Ben-Moshe <jats:italic>et al.</jats:italic> examined chiral nanocrystals of tellurium grown from solution using various electron microscopy and diffraction techniques (see the Perspective by Popov). They found that screw dislocation- mediated growth is responsible for chiral polyhedral shape formation, and chiral crystals can thus form even in the presence of achiral ligands. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="729" related-article-type="in-this-issue" vol="372">729</jats:related-article> ; see also p. <jats:related-article issue="6543" page="688" related-article-type="in-this-issue" vol="372">688</jats:related-article> </jats:p>

<jats:title>The evolution of ecological networks</jats:title> <jats:p> Plants and the animals that eat their fruits and disperse their seeds form complex networks of mutualistic interactions. The structures of many such networks and the ecological forces that shape them are well known, but their deeper evolutionary history has received little attention. Burin <jats:italic>et al.</jats:italic> address this knowledge gap in a study of frugivorious bird species in documented seed-dispersal networks around the world (see the Perspective by Bello and Barreto). Species occupying central positions in frugivory networks, which thus interact with many plant species, tend to belong to lineages that are more stable over macroevolutionary time scales. These patterns are more evident in regions with warmer and wetter climates and provide evidence that evolutionary processes can leave a signal on the structure of current ecological networks. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="733" related-article-type="in-this-issue" vol="372">733</jats:related-article> see also p. <jats:related-article issue="6543" page="682" related-article-type="in-this-issue" vol="372">682</jats:related-article> </jats:p>

<jats:title>Kids armed with anti-coronavirus B cells</jats:title> <jats:p> It remains unclear whether B cell repertoires against coronaviruses and other pathogens differ between adults and children and how important these distinctions are. Yang <jats:italic>et al.</jats:italic> analyzed blood samples from young children and adults, as well as tissues from deceased organ donors, characterizing the B cell receptor (BCR) repertoires specific to six common pathogens and two viruses that they had not seen before: Ebola virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Children had higher frequencies of B cells with convergent BCR heavy chains against previously encountered pathogens and higher frequencies of class-switched convergent B cell clones against SARS-CoV-2 and related coronaviruses. These findings suggest that encounters with coronaviruses in early life may produce cross-reactive memory B cell populations that contribute to divergent COVID-19 susceptibilities. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="738" related-article-type="in-this-issue" vol="372">738</jats:related-article> </jats:p>

<jats:title>Natural plutonium from supernovae</jats:title> <jats:p> The rapid neutron capture process (r-process) produces many of the heavy chemical elements, but the astrophysical settings where it occurs remain unclear. Leading candidates are neutron star mergers and some types of supernovae. Wallner <jats:italic>et al.</jats:italic> analyzed the plutonium content of a deep-sea crust sample, identifying a few dozen atoms of the r-process isotope plutonium- 244 that were delivered to Earth within the past few million years. There was a simultaneous signal of iron-60, which is known to be produced in supernovae. Comparing the ratios of these isotopes constrains the relative contributions of supernovae and neutron star mergers to r-process nucleosynthesis. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="742" related-article-type="in-this-issue" vol="372">742</jats:related-article> </jats:p>

<jats:title>Staying dry</jats:title> <jats:p> Is precipitation all that a watershed needs to recover from drought? Conventional wisdom says yes, but this is not necessarily true. Peterson <jats:italic>et al.</jats:italic> studied streamflow and precipitation in 161 watersheds in southeastern Australia across the Millennium Drought, which stuck the region during the first decade of the 21st century (see the Perspective by Tauro). They found that runoff in approximately one-third of the watersheds had not returned to predrought levels even after 7 years despite the resumption of more normal precipitation. The authors suggest that these longterm changes are due to water loss from increased transpiration. Watersheds may thus have multiple states and a finite resilience to transient disturbances, and hydrological droughts can persist long after meteorological droughts. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6543" page="745" related-article-type="in-this-issue" vol="372">745</jats:related-article> ; see also p. <jats:related-article issue="6543" page="680" related-article-type="in-this-issue" vol="372">680</jats:related-article> </jats:p>