Editors' Choice

Science  05 Dec 2014:
Vol. 346, Issue 6214, pp. 1196
  1. Microbiology

    Aiding shipworms' appetite for destruction

    1. Caroline Ash

    A shipworm removed from its wooden burrow

    PHOTO: R. M. O'CONNOR ET AL., PNAS 111, 47 (25 NOVEMBER 2014) © 2014 NATIONAL ACADEMY OF SCIENCES

    Shipworms are in fact mollusks that consume wood. They can cause devastation to wooden ships but they also clean up wreckage. Mollusks cannot eat wood unaided (the lack the right enzymes) so O'Connor et al. puzzled over the absence of symbiotic wooddigesting organisms in the gut of shipworms. To their surprise, they discovered that the gills of a shipworm called Bankia setacea harbored Teredinibacter turnerae bacteria, which produce several wood-digesting enzymes. It seems the shipworm's tissues not only tolerate but also selectively transfer these foreign enzymes into their guts for digesting its formidable meals.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1413110111 (2014).

  2. Stem Cells

    An inhibitor to expand mouse stem cells

    1. Beverly A. Purnell

    Among their many side effects, treatments such as chemotherapy and radiation deplete stem cells. Therapies to boost their numbers may positively affect patient outcomes. One possible therapeutic target is the protein phosphatase SHIP1. Hematopoietic stem cells expand in mice lacking SHIP1; however, they also develop inflammatory disease. To boost stem cells numbers while hopefully avoiding inflammation, Brooks et al. developed a SHIP1 inhibitor. Adult hematopoietic and mesenchymal stem cell numbers increased in normal mice treated transiently with the inhibitor. The inhibitor also helped mice recover their hematopoietic-lineage cells after radiation treatment.

    Stem Cells 10.1002/stem.1902 (2014).

  3. Superconductivity

    Beefing up thin-film superconductivity

    1. Jelena Stajic

    Conventional superconductors, such as lead, owe their exotic properties to the interaction of electrons and lattice vibrations. In contrast, in the more recently discovered iron-based superconductors (IBSs), magnetic interactions are thought to play a major role. Lee et al. show that in thin films of the IBS FeSe deposited on SrTiO3, a combination of the two mechanisms may be at play. Using angle-resolved photoemission spectroscopy, they discovered a vibrational mode of the SrTiO3 substrate that interacts with the electrons in FeSe. The interaction roughly doubles the temperature at which the film becomes superconducting, when compared with bulk IBSs with similar electronic structures.

    Nature 515, 245 (2014).

  4. Marine Biology

    Gray seals: the North Sea's great whites?

    1. Jia You

    Harbor porpoises with missing bellies first appeared on Dutch beaches in 2006; soon, dozens of mutilated porpoises began mysteriously and gruesomely washing ashore each year. Now, Leopold et al. have cracked the murderers' identity: gray seals. Photographs and autopsy results of more than 1000 stranded porpoises from 2003 to 2013 revealed torn blubber, scratch marks, and canine teeth marks—all pointing to seals. Finding the smoking gun—seal saliva DNA in the wounds—seemed impossible, as seawater should wash it away. But the team did find seal DNA at the bottom of deep narrow bite marks on three porpoises. Humans may be to blame for the change in seal hunting targets: With rising gas prices, fishermen switched from trawling to cheaper nets anchored to the seabed, which can also trap porpoises. The seals may have stumbled onto them and then gone on to hunt this larger, fattier prey.

    Proc. R. Soc. London ser. B, 10.1098/rspb.2014.2429(2014).

  5. Hearing Loss

    Supporting cells take on a starring role

    1. Paula A. Kiberstis

    Hair cells (green) and supporting cells (cyan) in a neonatal mouse cochlea

    PHOTO: GUOQIANG WAN

    “Supporting cells” in the inner ear have more to offer than their uninspiring name suggests. Studies of deafness often emphasize the role of hair cells, the sensory cells that transmit sound signals to the brain. Loss of hair cells causes permanent deafness, because these cells cannot regenerate. Loss of supporting cells also causes deafness, but a new study suggests that there may be hope. Mellado Lagarde et al. found that supporting cells can regenerate during a brief time period after birth. When they selectively eliminated supporting cells in newborn mice, nearby cells rapidly replaced them, thereby preserving hearing. The next step is to find a drug that induces regeneration.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1408064111 (2014).

  6. Nanomaterials

    Ionic charge manages transformation

    1. Phil Szuromi

    One way to create nanoparticles that otherwise are difficult to synthesize de novo is to swap out the cations of existing nanoparticles. De Trizio et al. show that the transformation of colloidal copper selenide (Cu2-xSe) nanoparticles with tin (Sn) ions leads to vastly different products for Sn2+ versus Sn4+. The smaller Sn4+ ions move readily through the Cu2-xSe lattice. The homogeneous transformation stops at Cu2SnSe3 and retains a cubic lattice. The larger Sn2+ cations are blocked, and regions of SnS form at the surface; the stress created at the interface of this heterogeneous nanoparticle drives the distortion of Se anion lattice that allows orthorhombic SnS to form.

    J. Am. Chem. Soc. 10.1021/ja508161c (2014).

  7. Tropical Paleoecology

    Revealing the forests of an ancient landmass

    1. Andrew M. Sugden

    The biogeographical history of Southeast Asia is complex. During the Pleistocene glacial cycles, sea levels repeatedly fell, exposing large areas of land and linking islands to the Asian mainland. Especially notable was Sundaland, which united Borneo, Sumatra, and the Malay Peninsula. But what kind of vegetation—forest or savannah—dominated this now-submerged landscape? To find out, Raes et al. combined geographical distribution models for species of the dominant dipterocarp tree family with models of past climates. They found that continuous rainforest was the most likely vegetation of much of Sundaland during the Pleistocene glacial cycles.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1403053111 (2014).

  8. Natural Hazards

    Getting a bigger jump on earthquakes

    1. Brent Grocholski

    Cleaning up after the 2014 Napa, California, earthquake

    PHOTO: LIU YILIN XINHUA NEWS AGENCY/NEWSCOM

    Developing better earthquake early warning (EEW) systems, which could help lessen earthquake damage, requires operational testing. Grapenthin et al. present a performance analysis of ShakeAlert, an EEW demonstration system along the western coast of the United States, during the 2014 magnitude 6.0 Napa earthquake. The system uses a real-time GPS network to pick up very early shaking and quickly estimate earthquake size and location. ShakeAlert successfully provided a slip model of the earthquake after only half a minute of shaking. The Napa quake shows that ShakeAlert works well and provides vital information on how EEW systems can be improved.

    Geophys. Res. Lett. 10.1002/2014 GL061923 (2014).

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