Editors' Choice

Science  16 Oct 2020:
Vol. 370, Issue 6514, pp. 306
  1. Physiology

    Enduring muscular courtship

    1. Caroline Ash

    The southern alligator lizard Elgaria multicarinata will grip the head of its mate for hours, thanks to specialized jaw muscle fibers.

    IMAGE: NHMLA COMMUNITY SCIENCE PROGRAM/CC BY-NC

    Several species of male amphibians and reptiles hold tight to their partners, possibly to prevent them mating with their rivals. The southern alligator lizard (Elgaria multicarinata) clamps its mate's head in its jaws for hours. This extreme muscular performance runs counter to expectations of reptilian muscle resilience. Nguyen et al. tested the sustained bite force of the adductor muscles of the lizard's jaw for fatigue. Muscle fibers can specialize, in terms of performance, into fast-acting twitch fibers and into slow-acting tonic fibers that are capable of fatigue-resistant contraction. Tonic fibers also exhibit slow calcium fluxes and relax slowly. The lizards' jaw muscle appears to have evolved to comprise fast-twitch fibers for eating and slow-tonic fibers that can sustain an extended courtship grip.

    Proc. R. Soc. London Ser. B 287, 20201578 (2020).

  2. Single-Cell Methods

    Watching information flow inside cells

    1. Di Jiang

    Each human cell has an information network like a subway system underpinning the function of one of the world's major cities. Instead of human couriers, within our cells, messenger RNAs (mRNAs) carry information. Thousands of mRNAs emerge from the cell's nucleus with instructions for cellular functions and disappear into the cytoplasm when their duties are fulfilled. Because of the development of single-cell sequencing techniques, we are now very good at counting these messengers, which are specific to each cell type in our body. Qiu et al. developed a new method to watch the movement of mRNAs. The technique can distinguish newly synthesized mRNAs from older ones and track each mRNA with a specific tag. This method provides a picture of the information flow inside cells and shows how they become disrupted by genetic perturbations that can cause cancer.

    Nat. Methods 17, 991 (2020).

  3. Immunology

    Imaging antigen-specific T cells

    1. Seth Thomas Scanlon

    Positron emission tomography (PET) has previously been exploited to trace immune responses in living animals. However, its use has been largely limited to cells expressing surrogate markers recognized by radiolabeled antibodies or cells genetically modified to take up radio-labeled substrates. Woodham et al. now report a nonintrusive, in vivo method to track antigen-specific T cells that recognize known antigens presented by major histocompatibility complex (MHC) molecules. The authors made a class of radiolabeled peptide-bound MHC dimers linked to antibody Fc regions, which they called “synTacs.” In a mouse model of cancer, they were able to follow CD8+ T cells within tumors that recognized a particular oncoprotein. They could also detect influenza virus (IAV) nucleoprotein–specific CD8+ T cells in the lungs of IAV-infected mice. This work may help pave the way for future tools to noninvasively track human T cell responses during interventions such as vaccination and cancer immunotherapy.

    Nat. Methods 17, 1025 (2020).

  4. Metallurgy

    Nature's guide for alloy design

    1. Brent Grocholski

    Metallic alloys composed of many different elements are often hard to identify and isolate because of the large number of potential combinations. Wei et al. started with a nine-element mixture and assessed the phase-separated zones that arose from natural mixing. They used the phase composition for designing a titanium-vanadium-niobium-hafnium refractory alloy with attractive ductility. This strategy provides a method for screening and isolating complex element compositions that may have outstanding properties.

    Nat. Mater. 10.1038/s41563-020-0750-4 (2020).

  5. Conservation

    Plastic trade-offs

    1. Sacha Vignieri

    The people who live around Bwindi Impenetrable Forest are skilled craftsfolk who select climbing plants for materials to make food-storage containers, thus avoiding the use of plastic alternatives that are not biodegradable.

    PHOTO: ANDREW AITCHISON/ALAMY STOCK PHOTO

    In just over 100 years, plastics have become both a necessity and a scourge, replacing natural materials in a myriad of uses and becoming a ubiquitous contaminant both in ecosystems and within organisms. For human populations in and around tropical forests, natural materials are available to process and store food. Bitariho et al. looked at trade-offs between using wild climbing plants to make baskets and winnowers and using plastic containers and devices. The authors accounted for food security, potential for plastic pollution, and the conservation status of 15 species of climbing plants around Bwindi Impenetrable National Park, Uganda. Families that had permission to collect wild climbing plants had more food storage and processing devices than those who did not. Although this study identified the risks of overharvesting one vulnerable climber species, it also showed that families with access to natural materials experienced greater food security and less plastic use and waste.

    Conserv. Sci. Pract. 2, e275 (2020).

  6. Optoelectronics

    Directing the flow of photocurrent

    1. Ian S. Osborne

    The next generation of information-processing devices is expected to be more energy efficient if the spin or valley degrees of freedom of a material is used to encode and carry information. Rasmita et al. show that circularly polarized light can induce a directional photocurrent in heterostructures of the two-dimensional transition metal dichalcogenides MoS2 and WSe2. The authors show that the direction of current flow is dependent on the polarization state of the light, and further control can be achieved with back-gating and an in-plane electric field. Combined with the possibility of engineering the heterostructures and the number of materials available with different properties, this work demonstrates that the monolayer transition metal dichalcogenides can serve as a versatile platform for future optoelectronic device technology.

    Optica 7, 1204 (2020).

  7. Arctic Ozone

    The hole truth

    1. H. Jesse Smith

    Ozone loss in the Arctic stratosphere has never been as severe as that in the Antarctic ozone hole, but during the past year, it declined to a level a bit closer to that of its southern counterpart. Wohltmann et al. report that during the northern spring of 2020, Arctic stratospheric ozone levels fell to near zero in some places. This unprecedented depletion, caused by unusually cold and stable conditions in the Arctic stratosphere, could become more frequent or extensive if the recent trend toward colder Arctic winters continues.

    Geophys. Res Lett. 10.1029/2020GL089547 (2020).

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