Editors' Choice

Science  27 May 2016:
Vol. 352, Issue 6289, pp. 1072
  1. Conservation

    Killing promotes killing

    1. Sacha Vignieri

    Legal hunting of protected wolves appears to increase poaching rather than tolerance.

    PHOTO: © AGE FOTOSTOCK/ALAMY STOCK PHOTO

    As a way to reduce poaching and promote tolerance of endangered species, some governments have implemented policies allowing the legal killing of large carnivores. Chapron and Treves investigated this controversial idea by studying the relationship between wolf population growth and announcements of legal hunting periods (either for individuals or as government-led culls) in the states of Michigan and Wisconsin. Contrary to the oft-stated argument that legal hunting reduces poaching, they found that population growth declined after both the announcements and the killing events. This suggests that legal killing may actually promote illegal killing, not tolerance.

    Proc. R. Soc. London Ser. B, 10.1098/rspb.2015.2939 (2016).

  2. Pluripotency

    Pluripotency factor opens chromatin

    1. Beverly A. Purnell

    All cells in an organism share the same genome. Differences in form and function arise from cells varying the specific genes they express. Temporal and spatial cues trigger changes in chromatin condensation: An open arrangement supports, whereas a closed conformation blocks, gene expression. Lopes Novo et al. report a chromatin-opening role for the pluripotency transcription factor NANOG, even in typically condensed areas of the genome, such as repetitive sequences. To do this, NANOG works with the SALL1, a protein associated with condensed chromatin. When embryonic stem cells differentiate, they compact their chromatin and simultaneously reduce NANOG expression. This work highlights how pluripotent cells link their pluripotency network with chromatin organization.

    Genes Dev. 30, 1101 (2016).

  3. Autoimmune Disease

    Lupus: subdivide in order to conquer?

    1. Paula A. Kiberstis

    For some diseases such as cancer, doctors routinely use molecular profiling to match patients to the most effective drugs, leading to improved patient care. With this goal in mind, Banchereau et al. explore the molecular heterogeneity of systemic lupus erythematosus, an autoimmune disease in which patients produce autoantibodies to nucleic acids. Through longitudinal profiling of blood samples from 158 children with lupus, they found a transcriptional signature in plasmablasts (a type of antibody-secreting cell) that strongly correlates with disease activity. Notably, a rise in neutrophil transcripts marked the onset of kidney inflammation. Overall, this approach revealed that lupus patients fall into seven subgroups, who conceivably would show different responses to treatment.

    Cell 165, 551 (2016).

  4. Citizen Science

    Crowd-sourcing craters on the Moon

    1. H. Jesse Smith

    Citizen science harnesses thousands of volunteers to perform tasks that are difficult to automate but too large for individual researchers. Bugiolacchi et al. present results from Moon Zoo, a website that asks users to identify the positions and sizes of lunar craters. Unfortunately, it is necessary to discard the majority of users' data during quality control, because most didn't correctly classify enough craters to become reliable at the task. Nevertheless, the project did result in crater counts comparable to those from experts, and it identified methods for future citizen science projects, such as how to weight users' expertise and combine all their results into a single catalog.

    Icarus 271, 30 (2016).

  5. Physics

    Watching phonons propagate

    1. Jelena Stajic

    In crystalline materials, atoms are arranged in an ordered lattice but can still wiggle around their equilibrium positions in concert with one another. These collective oscillations—phonons—are easy to describe in perfect crystals. In the real world, however, materials have nanoscale defects that can influence how phonons move through the crystal. To see these effects directly, Cremons et al. optically excited phonons in samples of WSe2 and Ge and watched them propagate. The phonons caused minute rearrangements of the lattice, which were captured by an ultrafast electron microscope. The resulting movies indicate that the phonons were generated at the step edges of the samples and that their motion was influenced by the local morphology.

    Nat. Commun. 7, 11230 (2016).

  6. Global Fresh Water

    The wet and the dry

    1. H. Jesse Smith

    If predicting the availability of water during the next century were as easy as the phrase “the wet get wetter and the dry get drier” would seem to suggest, then planning for it also would be easy. However, although that simple formulation is useful when considering latitudinal averages, detailed predictions are more difficult, because atmospheric circulation patterns will change as the world warms, and so moisture will be delivered to different areas on a regional scale. Wills et al. examine this issue in more detail and conclude that moisture flux variations in the tropics will occur mostly because of changes in stationary-eddy circulations, whereas transient eddies will be most important in the extratropics.

    Geophys. Res. Lett. 10.1002/2016GL068418 (2016).

  7. Microbiology

    A secret(e) weapon for food poisoning

    1. Caroline Ash

    Listeria monocytogenes secrete a toxin that allows them to overwhelm good gut microbes.

    CREDIT: SCIENCE PICTURE CO/SCIENCE SOURCE

    Trillions of microbes reside in our gut, producing essential nutrients and defending gut integrity. So how do a few incoming pathogens compete against these masses to establish an infection? Some strains of the bacteria Listeria monocytogenes cause gastroenteritis, which can be fatal in the immunocompromised and in pregnant women. Studying mice, Quereda et al. found that a virulent strain of L. monocytogenes produces a toxin called listeriolysin S, but only when it is in the gut. The toxin led to changes in the abundance of acetate- and butyrate-producing gut resident microbes in L. monocytogenes–infected mice. These short-chain fatty acids can inhibit L. monocytogenes growth, implying that L. monocytogenes expresses the toxin to overwhelm resident microbial competition.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1523899113 (2016).