Editors' Choice

Science  10 Apr 2015:
Vol. 348, Issue 6231, pp. 197
  1. Inflammation

    How smoking makes infection worse

    1. Kristen L. Mueller

    Smoking increases inflammation and worsens infection

    PHOTO: © ROSEMARY ROBERTS/ALAMY

    Smoking not only increases your risk of cancer but also increases inflammation and slows down recovery from infections, especially in people who have chronic obstructive pulmonary disorder (COPD). People with severe COPD have elevated levels of the cytokine interleukin-33 (IL-33), a secreted protein that promotes airway inflammation. To determine whether IL-33 triggers exaggerated inflammatory responses in COPD, Kearley et al. exposed mice lacking IL-33 to cigarette smoke and then infected them with influenza. A deficiency in IL-33 protected mice from excessive inflammation and weight loss. Cigarette smoke led to elevated production of IL-33 and altered expression of its receptor in exposed mice, causing lung inflammation to amplify.

    Immunity 42, 566 (2015).

  2. Cellular Mechanics

    The mechanics of cellular left and right

    1. Monika S. Magon

    Cells need to distinguish between left and right to interact during collective movement or embryonic development. To reveal the underlying cellular mechanics, Tee et al. studied the organization of actin in human cells using fluorescence, electron microscopy, and computational simulations. Actin fibers forming the cellular skeleton rearranged themselves from a symmetric to an asymmetric pattern through interplay between two types of fibers. The unidirectional tilting of the radial fibers and swirling of the transverse fibers were driven by contractile stress and rotational growth. The actin-crosslinking protein controlled the clockwise or anticlockwise dynamics of the actin network, establishing the left-right asymmetry of the cell.

    Nat. Cell Biol. 10.1038/ncb3137 (2015).

  3. Community Ecology

    Measuring effective dispersal

    1. Andrew M. Sugden

    Gallotia galloti is an important seed disperser on Tenerife

    IMAGE: © CULTURA RM/ALAMY

    Dispersal fundamentally shapes ecological communities and maintains biodiversity, yet it is extremely difficult to quantify. Estimating seed dispersal effectiveness (SDE) requires measurement of both the number of seeds dispersed and the probability of successful germination. González-Castro et al. laboriously measured the SDE of frugivorous lizards and birds as dispersers of seeds over 6 years in plant communities on the oceanic island of Tenerife. Their results allowed for comparisons between the SDE of the two main frugivore groups for different plant species and different communities (such as woodland and shrubland), revealing the networks of mutualistic interactions that underpin community persistence.

    Ecology 96, 808 (2015).

  4. Crime and Punishment

    Rethink jail for juvenile justice

    1. Brad Wible

    The U.S. criminal justice system is strikingly punitive: The incarcerations-to-convictions ratio is 70% larger than that of the next highest country. The U.S. juvenile incarceration rate is five times larger than that of any other country. But we don't randomly assign juveniles to jail, and thus it's difficult to isolate the impacts of incarceration on later-life outcomes, versus the impacts of underlying socioeconomic, cognitive, and other factors that influence juvenile criminal behavior as well as education, employment, and other outcomes. Studying 10 years of data on over 35,000 Chicago juvenile offenders, Aizer and Doyle noticed that judges were randomly assigned to juvenile cases, and judges had different tendencies to sentence incarceration versus probation. Assignment to a high–incarceration-rate judge decreased the likelihood of juveniles completing high school and increased the likelihood of adult incarceration.

    Quart. J. Econ. 10.1093/qje/qjv003 (2015).

  5. Neurodegeneration

    Deconstructing cell death in MS

    1. Paula A. Kiberstis

    Oligodendrocytes are often referred to as “support” cells for neurons, but in fact they play a critical role in the transmission of nerve impulses. These cells produce the myelin sheath that surrounds and protects axons in the central nervous system. In multiple sclerosis (MS), this myelin sheath erodes because of an inflammatory reaction that triggers the death of oligodendrocytes. Several distinct mechanisms of cell death exist, and understanding which one underlies oligodendrocyte death could lead to new therapies. Studying mouse models of MS, Ofengeim et al. find that oligodendrocytes die by a regulated process called necroptosis. A small-molecule inhibitor of a protein kinase that mediates necroptosis prevented oligodendrocyte death in the mouse models.

    Cell Rep. 10, 1836 (2015).

    IMAGE: C. MORENO ET AL., NANO LETTERS (10 MARCH 2015) © 2015 AMERICAN CHEMICAL SOCIETY
  6. Surface Imaging

    Submolecular resolution in 3D

    1. Phil Szuromi

    Surface probe microscopy has recently achieved submolecular resolution with metal tips made atomically sharp by decorating them with adsorbed molecules such as carbon monoxide. This method works well with adsorbed molecules that are small or flat. Moreno et al. now show how to achieve subatomic resolution in atomic force microscopy with commercial silicon tips, for three-dimensional structures such as absorbed fullerene molecules or the step edges of oxide surfaces. The van der Waals interaction is mapped with the tip a few nanometers above the surface in a closed feedback loop. A second higher-resolution scan with an open feedback loop follows this map with a constant offset distance that is adjusted to provide high resolution.

    Nano Lett. 10.1021/nl504182w (2015).

  7. Physics

    Pairing in an off-kilter atomic gas

    1. Jelena Stajic

    In a process called Cooper pairing, two electrons of opposite spin and momentum form a pair and join a larger “condensate” to flow effortlessly through a superconducting material. In cold atomic gases, the atomic state plays the role of the spin. But what happens if there is a different number of atoms in the two spin states, so that pairing cannot be perfect? Ong et al. tackled that question for 6Li atoms trapped in a weakly coupled array of pancakeshaped clouds. As they cranked up the interaction between the atoms and increased the relative number of minority spins, the gas in each pancake separated into a core of paired spins surrounded by the majority atoms.

    Phys. Rev. Lett. 114, 110403 (2015).

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