Catálogo de publicaciones - revistas

<jats:title>Specifying one oocyte from many</jats:title> <jats:p> In many animals, only one cell from a cyst of germ cells is selected to become the oocyte. Using fruit flies as a model, Nashchekin <jats:italic>et al</jats:italic> . identified the microtubule minus end-binding protein Patronin/CAMSAP as a key factor for specifying oocyte fate. Patronin amplifies an initial asymmetry provided by the fusome to form a noncentrosomal microtubule network focused on one cell, along which dynein transports oocyte fate determinants. This mechanism for selecting a single oocyte may be shared in other organisms. —BAP </jats:p>

<jats:title>Valuing vaccination</jats:title> <jats:p> Using money as a motivation for the public to get vaccinated is controversial and has had mixed results in studies, few of which have been randomized trials. To test the effect of money as an incentive to obtain a vaccine, Campos-Mercade <jats:italic>et al</jats:italic> . set up a study in Sweden in 2021, when various age groups were first made eligible to receive the severe acute respiratory coronavirus 2 vaccine (see the Perspective by Jecker). The effect of a small cash reward, around US $24, was compared with the effect of several behavioral nudges. The outcome of this preregistered, randomized clinical trial was that money had the power to increase participation by about 4 percentage points. Nudging and reminding didn’t seem to be deleterious and even had a small positive effect. Of course, the question of whether it is ethical to pay people to be vaccinated like this needs to be addressed. —CA </jats:p>

<jats:title>How Integrator ends transcription early</jats:title> <jats:p> Transcription is the central process that activates the genetic information in cells, but our understanding of how gene transcription is regulated is incomplete. The so-called Integrator can stop the transcribing enzyme RNA polymerase II at the beginning of genes, but how such downregulation of transcription occurs is unclear. Fianu <jats:italic>et al</jats:italic> . present the three-dimensional structure of Integrator bound to the transcribing polymerase complex, providing molecular and mechanistic insights into how Integrator mediates transcription regulation. —DJ </jats:p>

<jats:title>Sample return shows late lunar volcanism</jats:title> <jats:p> Measuring physical samples of Solar System bodies in the laboratory provides more information than is possible from remote sensing alone. In December 2020, the Chang’e-5 mission landed on the Moon, collected samples, and returned them to Earth. Che <jats:italic>et al</jats:italic> . analyze two fragments of volcanic lunar basalt collected by Chang’e-5. Radiometric dating using lead isotopes indicated that the rocks formed from magma that erupted about 2 billion years ago, later than other volcanic lunar samples. The abundance of extinct radioactive elements in the rock is too low for radioactive heating to have produced the magma. Another, thus far unknown, source must be responsible for the late lunar volcanism. —KTS </jats:p>

<jats:title>Lower mantle “garbage can”</jats:title> <jats:p> Calcium silicate perovskite has finally been identified in a natural sample and now has the mineral name davemaoite. Tschauner <jats:italic>et al</jats:italic> . discovered the type mineral trapped at high pressure and temperature as a diamond inclusion (see the Perspective by Fei). Structural and chemical analysis of the mineral showed that it is able to host a wide variety of elements, not unlike fitting bulky objects into garbage can. Specifically, it has a large amount of trapped potassium. Davemaoite can thus host three of the major heat-producing elements (uranium and thorium were previously shown experimentally) affecting heat generation in Earth’s lower mantle. —BG </jats:p>

<jats:title>Coaling in the deep</jats:title> <jats:p> Despite our current reliance on fossil carbon for energy, the biogeochemical reactions that produce coal and natural gas aren’t entirely understood. Lloyd <jats:italic>et al</jats:italic> . tested the chemistry and isotope composition in samples ranging from wood to hard, mature coal (see the Perspective by Keppler). Methyoxyl groups in this organic material, which are a potential source of methane, declined with maturity, whereas the carbon-13 fraction increased gradually. The most plausible explanation for this observed pattern is biological demethylation under substrate-limited conditions. These results help us understand the processes that form coal and natural gas on geologic time scales. —MAF </jats:p>

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

<jats:title>Caution around the fountain of youth</jats:title> <jats:p> The scientific and popular literature is full of claims for diets that delay or reverse the aging process (at least in model organisms). But how do these interventions work? Is it the amount of food, the timing of food intake, the proportion of certain macronutrients? In a Review, Lee <jats:italic>et al</jats:italic> . explore the fact and fiction of dietary prescriptions for a healthier and longer life. They propose that one unifying concept may be convergence on the signaling pathway mediated by the protein kinase mTOR (mechanistic target of rapamycin). Another conclusion is that the efficacy and safety of these diets for humans largely remain to be established. —LBR </jats:p>

<jats:title>X chromosome activity in primates</jats:title> <jats:p> Mammalian X and Y sex chromosomes differ greatly in structure and gene content. Therefore, mechanisms are in place to ensure that there is balanced gene dosage between the X chromosome and autosomes and between the sexes. Quite a bit is known about dosage compensation in mice; however, the mechanism in primates, including humans, is less clear. Okamoto <jats:italic>et al</jats:italic> . reveal that in cynomolgus monkeys, the X chromosomes display repressive modifications and compacted structure before being chosen as active or inactive X chromosomes (see the Perspective by Heard and Rougeulle). This work elucidates the pathway, timing, and progression of X chromosome dosage compensation during monkey development, creating a foundation for elucidating this mechanism in other primates, including humans. —BAP </jats:p>