Editors' Choice

Science  02 Mar 2018:
Vol. 359, Issue 6379, pp. 1005
  1. Anthropology

    Ablaze in Pleistocene Italy

    1. Caroline Ash

    Remains of charred boxwood sticks show how Neandertals made tools.

    PHOTO: CARO/RUPERT OBERHAEUSER/NEWSCOM

    As engravers know, boxwood is dense and hard. Neandertals knew this too. Nevertheless, wooden artifacts are vulnerable to decay, and such finds are rare and exciting. During excavations for a spa in central Italy, Aranguren et al. found remains of elephants, together with remnants of more than 50 burnt wooden sticks dating from around 170,000 years ago. Back then, this area consisted of patches of hotspring wetlands surrounded by grass and box shrub (Buxus sempervirens), through which elephant and deer roamed. The Neandertals apparently selected boxwood for its hardness and charred it to make shaping of the tough wood with flint tools a little easier. The tools appear to be multipurpose digging sticks with rounded handles and pointed tips. Tools of similar dimensions and technology were, until recently, also part of the essential equipment of modern hunter-gatherers.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1716068115 (2018).

  2. Immunology

    Commensals direct wound healing

    1. Seth Thomas Scanlon

    Human skin is coated with microorganisms, some of which can cause serious infection when the skin barrier is wounded. But not always. Microorganisms on all barrier surfaces are continually monitored by the host's various immune responses. Linehan et al. found that the skin-dwelling organism Staphylococcus epidermidis specifically prompts an ancient arm of the immune system (the major histocompatibility complex class 1b molecule H2-M3) to respond in a way that avoids inflammation—distinct from responses to pathogens. H2-M3 processes and presents S. epidermidis–derived N-formyl methionine peptides to CD8+ T cells. These cells express immunoregulatory and tissue-repair gene signatures and accelerate skin wound healing. Hence, hosts and microbiota can interact in highly beneficial ways that may hold promise for therapeutic interventions.

    Cell 10.1016/j.cell.2017.12.033 (2018).

  3. Astronomy

    Why don't astronomers publish observations?

    1. Keith T. Smith

    The La Silla Observatory in Chile, an ESO facility

    PHOTO: ESO/JOSÉ FRANCISCO SALGADO, CC BY 4.0

    Observing time on top astronomical telescopes is heavily oversubscribed and allocated through a competitive proposal process, but 30 to 50% of observations never produce a peer-reviewed paper. Patat et al. contacted principal investigators on proposals executed by the European Southern Observatory (ESO) between 2006 and 2013 that did not result in publication. They found several recurrent issues, such as poor observing weather, lack of investigator resources for analysis, or personnel having left research. By comparing publication rates over time, they showed that 50% of publications occur within 3.5 years of the observations, but it takes 10 years for that fraction to reach 95%. Astronomers are struggling to keep up with the flow of data.

    Messenger 170, 51 (2017).

  4. Immunogenetics

    Context for immune responses

    1. Laura M. Zahn

    Immune cells function by recognizing pathogens and initiating a complex cellular response to mount a defense. People can show a wide range of genetically driven variation in responses to infection. Alasoo et al. asked how the cellular environment drives change in noncoding regions associated with transcription in immune cells. Chromatin accessibility and gene expression change in pluripotent stem cell lines exposed to signals simulating bacterial infections. Genetic variants among these cell lines affected the timing of gene expression, depending on to what they were exposed. Interestingly, disease-risk variants associated with immune dysfunction, such as rheumatoid arthritis and inflammatory bowel disease, emerged from the analyses.

    Nat. Genet. 10.1038/s41588-018-0046-7 (2018).

  5. Neurodevelopment

    Regulated tether controls asymmetric cell fate

    1. Pamela J. Hines

    In the developing fruitfly, the transcription factor Prospero regulates cellular quiescence and fate. Hannaford et al. show how an adaptor protein called Miranda manages Prospero activities through sequestration. During interphase in neuroblasts, Miranda binds directly to lipids of the plasma membrane, keeping Prospero away from the cellular nucleus, where it could incite quiescence. During metaphase, thanks to a key phosphorylation, Miranda instead binds to actin bundles at the basal pole of the cell. Prospero, thus tethered, is delivered to one but not the other of the daughter cells, leading to asymmetric allocation of cellular fate.

    eLife 7, e29939 (2018).

  6. Biosynthesis

    A fitting way to finish

    1. Michael A. Funk

    The cofactor heme is used by enzymes to perform challenging oxidations, including reactions on the cofactor itself. Streit et al. used spectroscopy to identify a tyrosyl radical formed during the final step of heme biosynthesis. Analysis of the reaction kinetics suggests that the radical is generated by a high-valent iron intermediate created by reaction of hydrogen peroxide with the substrate, which also serves as a cofactor in the reaction. The authors propose that the tyrosyl radical abstracts a hydrogen atom from the substrate, leading to formation of the product, heme b, by oxidative decarboxylation of the propionic acid side chains.

    J. Biol. Chem. 10.1074/jbc.RA117.000830 (2018).

  7. Fluorine Chemistry

    F caught in a bridge

    1. Jake Yeston

    Fluorine typically forms a single bond and then clings to the rest of its electrons with an unrivalled grip. Recently, though, the reactivity of a rigid polycyclic test compound suggested that a fluorine atom could fleetingly bridge two carbon centers in a (C–F–C)+ fluoronium motif. Pitts et al. have now spotted that intermediate directly, using a combination of 19F, 1H, and 13C nuclear magnetic resonance spectroscopy. They started at −120°C, but it turned out that the bridge motif was stable up to −40°C.

    Angew. Chem. Int. Ed. 57, 1924 (2018).