Editors' Choice

Science  11 Aug 2017:
Vol. 357, Issue 6351, pp. 561
  1. Developmental Biology

    The making of a distal gut

    1. Beverly A. Purnell

    Improving neural stem cell motility

    CREDIT: J. O. MÚNERA ET AL. CELL STEM CELL 21 (2017) © CELL PRESS

    Organoid research is revolutionizing investigations into development and disease. Gut organoids have proved valuable in elucidating signaling pathways and structures. So far, most advances have focused on the small intestine. The distal gut has seen less progress because of the challenges of deriving organoids from cecum, colon, and rectum stem cells. Múnera et al. show that it is essential to have specific growth factors called BMP-HOX present to generate human colonic organoids. When transplanted, these organoids grow into tissues in mice that resemble the human colon. Insights into colitis, colon cancer, and irritable bowel syndrome should now be enabled through the use of these models of the distal human gut.

    Cell Stem Cell 21, 51 (2017).

  2. Earthquakes

    A new earthquake forecast for California

    1. Brent Grocholski

    Earthquakes cannot be predicted, but rupture models can estimate the regional likelihood of an earthquake within a certain time window. Field et al. incorporate new data and fault-based information for the Third Uniform California Earthquake Rupture Forecast (UCERF3). The new model better accounts for potential multiple fault ruptures and provides self-consistent forecasting windows from hours to more than a century. UCERF3 is an important development for operational forecasts that are vital for assessing the evolving seismic hazard in California.

    Seismol. Res. Lett. 10.1785/0220170045 (2017).

  3. Ecology

    A benevolent invader?

    1. Andrew M. Sugden

    Plant and animal species introduced into non-native localities by humans sometimes become invasive, often with damaging ecological and economic consequences. However, Ramus et al. report an unusual case where an invasive species can be beneficial. Gracilaria vermiculophylla is a seaweed from the West Pacific that has been introduced to North Atlantic coastlines, where it has become invasive. In experimental manipulations of its abundance in North Carolina, USA, the seaweed enhanced an array of ecosystem functions by assuming the role of a “foundation” species that provides habitat for others. Benefits accrued to the abundance and species richness of gastropods and crustaceans and, through the attenuation of water flow, to coastal protection. Hence, toleration rather than eradication may be a pragmatic management strategy in this case.

    An invasive West Pacific seaweed proves protective on the U.S. eastern seaboard.

    PHOTO: LARS BRAMMER NEJRUP/NOBANIS, HTTP://WWW.NOBANIS.ORG

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1700353114 (2017).

  4. Climate Change

    The long reach of Arctic sea ice loss

    1. H. Jesse Smith

    Arctic sea ice quantifiably affects global climate.

    PHOTO: VICKI BEAVER/ALAMY STOCK PHOTO

    How might the loss of Arctic sea ice be affecting climate outside that region? Climate change is driven by a number of interacting processes, including sea ice loss and increasing atmospheric carbon dioxide concentrations, and separating their effects is not a trivial exercise. McCusker et al. used a coupled ocean-atmosphere general circulation model to unravel the impacts of sea ice loss and atmospheric carbon dioxide increases on temperature and circulation; they found that these impacts can be distinguished quite precisely, on hemispheric to regional scales. The ability to separate these effects might help us better interpret the diverse and sometimes apparently conflicting array of modeling and observational studies of Arctic climate change and its influence.

    Geophys. Res. Lett. 10.1002/2017GL074327 (2017).

  5. Superconductivity

    Making sense of the cuprate pseudogap

    1. Jelena Stajic

    One of the outstanding questions in the physics of cuprate high-temperature superconductors is whether the so-called pseudogap—a depression in the density of states around Fermi energy that occurs above the superconducting transition temperature—is caused by a true phase transition. Sato et al. measured the magnetic torque in the compound YBa2Cu3Oy with high precision and found a kink in the magnetic anisotropy for several samples of varying concentrations of oxygen. For all of these samples, the kink occurred very close to the temperature that marks the beginning of the pseudogap phase. These findings provide evidence that additional rotational symmetry breaking occurs at the entrance to the pseudogap phase.

    Nat. Phys. 10.1038/NPHYS4205 (2017).

  6. Obesity

    Hold your nose to prevent obesity

    1. Gemma Alderton

    The sense of smell (olfaction) can affect the appreciation and anticipation of food. Riera et al. found that the activity of olfactory sensory neurons also influences energy regulation. Inhibition of olfactory perception in lean mice and mice with diet-induced obesity showed that losing the sense of smell resulted in leaner mice, but not because they ate less. Mice that could not smell had higher levels of energy expenditure and fat-burning capacity because sympathetic nerve activity became elevated in adipose tissue. Conversely, mice with hypersensitive olfaction had greater adiposity and exhibited signs of diabetes. It appears that being able to smell has a direct systemic effect on regulating body energy homeostasis.

    Cell Metab. 26, 198 (2017).

  7. Neural Stem Cells

    Mobilized by electricity

    1. Lisa D. Chong

    Harnessing neural stem cells to repair brain damage is difficult. Endogenous stem cells are located deep in the brain's hippocampus and subventricular zone (SVZ), and upon transplantation, stem cells often exhibit poor motility. Feng et al. have developed a model of transplanted, fluorescent-labeled human neural stem cells in the SVZ of the rat brain. The cells can be encouraged to migrate in a specific direction in response to an intermittent electric field emitted by implanted electrodes. Endogenous stem cells travel along the rostral migratory path from the SVZ to the olfactory bulb. An electric field can coax transplanted stem cells in different directions, and some cells remained viable and expressed differentiation markers several weeks later.

    Stem Cell Rep. 9, 177 (2017).

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