Editors' Choice

Science  28 Aug 2015:
Vol. 349, Issue 6251, pp. 940
  1. Pesticides

    The effects of pesticides run deep

    1. Sacha Vignieri

    Pesticides affect earthworms in a variety of ways

    PHOTO: © ALEX FIELDHOUSE/ALAMY

    Many pesticides negatively affect pollinators, such as bees, but how do they affect soil-dwelling organisms such as earthworms, which help enhance the nutrient availability of soil? Gaupp-Berghausen et al. addressed this by testing the effects of a commonly used glyphosphate-containing herbicide on two species of earthworms in a greenhouse experiment. They found that herbicide treatment reduced an activity called casting that promotes soil health in one species and decreased the ability of the other species to reproduce by nearly 50%. Soil concentrations of nitrate and phosphate, which can negatively affect the surrounding environment, also increased. These results emphasize that pesticides probably have effects on ecosystems that go well beyond what we might predict or recognize.

    Sci. Rep. 5, 12886 (2015).

  2. Applied Optics

    Adding communication to light harvesting

    1. Ian S. Osborne

    Solar cells are often thought of as passive devices sitting on a rooftop, benignly soaking up sunlight and converting it into useful electricity. On the smaller scale, they can be integrated into electrical devices, removing the need for a battery. Zhang et al. now show that solar cells can also function as data detectors. Using visible light communication, a wireless medium in which information can be encoded and transferred as an optical signal piggybacking on the light from an LED source, they demonstrate high-speed data communication. The flexibility and relatively low cost of organic solar cells provide the possibility of integrating such self-powered devices into the “Internet of things.”

    Optica 2, 607 (2015).

  3. Organic Chemistry

    An E-Z route to photobases

    1. Phil Szuromi

    Although many stable photoactivated acids are known, there are fewer examples of photoactivated Lewis bases, most of which form by the liberation of protecting or blocking groups. He et al. report that a molecule with a conjugated nitrogen framework, a triazabutadiene, becomes more basic in water (by almost one pH unit) when the absorption of ultraviolet light rotates a double bond and converts the E isomer to the Z form. An organic-soluble derivative was used to catalyze a condensation reaction, the Henry reaction between nitroethane and p-nitrobenzaldehyde.

    J. Am. Chem. Soc. 10.1021/jacs.5b04367 (2015).

  4. Geochemistry

    Core composition gets nebular

    1. Brent Grocholski

    Piece of a rare angrite meteorite

    PHOTO: JON TAYLOR/FLICKR

    The composition of Earth's core is a key piece of evidence needed to determine how and from what sources it was formed. The core is composed mainly of a mixture of iron and nickel but also contains unknown amounts of other elements, including silicon. Dauphas et al. find that the isotopic composition of silicon in a particular class of meteorites called angrites is identical to that of Earth's mantle and probably was inherited from the solar nebula. This unexpected observation suggests that there is less silicon in the core than previously thought, and in general muddies the use of its isotopes to constrain the amount of silicon in planetary cores.

    Earth Planet. Sci. Lett. 10.1016/j.epsl.2015.07.008 (2015).

  5. Taste

    Does this taste fatty to you?

    1. Laura Schuhmacher

    Fat, like sweetness, sourness, bitterness, and saltiness, may be a distinct taste

    PHOTO: DRAGONIMAGES/THINKSTOCK

    Just as food can be too salty or too sweet, we also complain if food is too oily or fatty. But is that judgement based on the distinct taste of fat, or is it just a mix of other basic tastes and textures? Running et al. now report that our primary taste senses have a previously unknown sibling, dubbed “oleogustus.” They asked 48 volunteers to sort 15 taste samples by quality, and most of them could distinguish long-chained nonesterified fatty acids (NEFAs) such as oleic acid from sweet, sour, salty, bitter, and umami substances, whereas short-chained NEFAs such as citric acid tasted sour. The results may be important to the food industry, such as when selecting fat replacers.

    Chem. Senses 10.1093/chemse/bjv036 (2015).

  6. Heart Disease

    A cadherin gene enters MVP territory

    1. Paula A. Kiberstis

    The average human heart beats about 100,000 times daily. With each beat, the heart's four valves open and close tightly in a synchronized fashion, ensuring that blood flows in only one direction. For the 1 in 40 people with mitral valve prolapse (MVP), the valve between the heart's two left chambers does not close properly, which can cause blood to leak backward, reducing the heart's efficiency. Durst et al. studied three families predisposed to MVP and found mutations in a gene coding for a specific cadherin, a group of proteins that help cells adhere to one another. Studies in mice revealed that the mutations disrupt how cells move and organize themselves during heart valve morphogenesis.

    Nature 10.1038/nature14670 (2015).

  7. Computational Biology

    Deciphering function from single-cell data

    1. L. Bryan Ray

    Given their wide range of duties, cells must make tradeoffs between optimal performance and the ability to multitask. Scientists have proposed that groups of cells do this by arranging themselves in the shape of a polygon, in which cells at the vertices express distinct genes optimized for different tasks. |Korem et al. analyzed single-cell measurements of gene expression in various mouse and human tissues and confirmed that cells do organize themselves in this manner. Some tissues showed distinct clusters or well-separated cell types, whereas other tissues had cells with a continuum of gene expression profiles. Examining the gene expression patterns in the cells closest to the vertices may reveal unknown functions for such cells.

    PLOS Comput. Biol. 11, e1004224 (2015).

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