Editors' Choice

Science  24 Jun 2016:
Vol. 352, Issue 6293, pp. 1531
  1. Infectious Disease

    Disease information-seeking behavior

    1. Caroline Ash

    Google Trends data allow for monitoring of disease outbreaks.

    PHOTO: HARTPHOTOGRAPHY/SHUTTERSTOCK.COM

    Chicken pox is usually a mild disease of children and, consequently, national vaccination and reporting policies vary widely. In countries that do not immunize against chicken pox, Google Trends recorded a strong seasonal signal in search behavior for information about chicken pox. Tellingly, Bakker et al. found that the seasonal search signal reverses between the Southern and Northern Hemispheres and declines when a country mandates vaccination. Thus, Google data allow for monitoring of an underreported viral infection, forecasting outbreaks and measuring the impact of immunization for chicken pox, and perhaps also for other seasonal childhood infections.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1523941113 (2016).

  2. Physics

    A partially protected surface state

    1. Jelena Stajic

    A signature feature of topological insulators is conductive surface states that are immune to certain types of disorder. This “topological protection” appears to be at work in compounds such as Bi2Se3, in which electrons interact with one another only weakly. Whether these protected surface states exist in SmB6, a material whose insulating bulk is caused by strong electronic correlations, is still a subject of debate. Park et al. used a tunneling technique to find states on the surface of SmB6 that appeared to have the same linear dispersion as those in Bi2Se3 but were only partially protected. The loss of protection was caused by the interaction of the surface states with the magnetic excitations of the bulk.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1606042113 (2016).

  3. Extrasolar Planets

    Can a red dwarf host a habitable planet?

    1. Keith T. Smith

    A flaring red dwarf star in the nearby system DG Canum Venaticorum.

    PHOTO: NASA'S GODDARD SPACE FLIGHT CENTER/S. WIESSINGER

    The habitable zone is a region around a star where an Earth-mass planet with an Earth-like atmosphere would have a surface temperature of 0° to 100°C. Owen and Mohanty model planets in the habitable zone of red dwarfs, which are by far the most common type of star. These planets form with a hydrogen/helium envelope, and the greenhouse effect makes their surfaces too hot. Radiation from the star can strip away the envelope from a Venus-mass planet, causing it to fit the “habitable” criteria within a reasonable time. But the stronger gravity of an Earth-mass planet prevents it from ever losing enough of the envelope to cool down and become habitable.

    Mon. Not. R. Astron. Soc. 459, 4088 (2016).

  4. Biophysics

    From the green glow to the deep tunnel

    1. Jake Yeston

    Once green fluorescent protein has unleashed its eponymous green glow, a proton must journey back to the chromophore to reset the photophysical cycle. Salna et al. have now timed that journey over a temperature range from ambient temperature to down below −190 °C. Based on the large and temperature-dependent rate differences associated with isotopic substitution by deuterium, they conclude that quantum-mechanical tunneling plays a central role in the process. Specifically, the OH group on a serine residue participates in the proton transfer chain, despite its comparatively low acidity. Deep tunneling by serine's proton, at energies well below the threshold for classical deprotonation, helps bias overall transport in the right direction.

    Nature Chem. 10.1038/NCHEM.2527 (2016).

  5. cell Biology

    Exploring the human proteome

    1. Valda Vinson

    Although we know the sequence of the human genome, a large fraction of the human proteome remains poorly characterized. To overcome this, Leonetti et al. combine two methods to achieve high-throughput tagging of human proteins. First, they use the CRISPR/Cas9 system to insert DNA that includes a sequence encoding the tag, a short piece of green fluorescent protein (GFP), as well as sequences homologous to targeted genes. Second, they coexpress the remaining part of GFP in the same cell, which binds to the tag to give fluorescent GFP. Such tagging will probably provide new insights into the functions of proteins and pave the way for proteome-wide analysis of human cells.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1606731113 (2016).

  6. Vascular Repair

    Macrophages moonlight in brain bleeds

    1. Beverly A. Purnell

    Microbleeds, which occur when microvessels in the brain rupture, are associated with cerebrovascular disease, dementia, and normal aging. Their rapid repair helps the body avoid more serious damage. To better understand this process, Liu et al. used a high-energy laser to generate endothelial lesions in the brains of zebrafish and discovered that macrophages, better known for their role in inflammation in phagocytosis, help to repair ruptured cells. As observed through time-lapse imaging in live fish, a macrophage arrives at the lesion and extends a cellular appendage to each of the lesion's ends. The macrophage then generates mechanical traction forces that bring the two ruptured ends together for lesion repair.

    Macrophages (green) help repair ruptured blood vessels (red/yellow) in the brain.

    PHOTO: LIU ET AL.; IMMUNITY 44 (17 MAY 2016) © CELL PRESS

    Immunity 17, 1162 (2016).

  7. Cancer

    Tumor cells fatten up to adapt

    1. Lisa D. Chong

    How do cancer cells adapt to the low-oxygen and acidic conditions of the tumor microenvironment and then proliferate and spread? Menard et al. propose that they overcome these stressful conditions by storing up energy in the form of fat droplets. Cancer cells, such as glioblastoma, boosted their uptake of certain lipoproteins under these harsh conditions. In a mouse model of metastasis, this uptake increased the spread of cancer cells. Tumor cells internalized fluorescently labeled lipids by endocytosis, which required them to express heparin sulfate proteoglycans and larger amounts of lipoprotein receptors on their surface. A potential therapeutic route might be to block tumor cells from accumulating these fat reserves.

    Cancer Res. 10.1158/0008-5472.CAN-15-2831 (2016).