Editors' Choice

Science  03 Apr 2015:
Vol. 348, Issue 6230, pp. 88
  1. Prion Transmission

    Prion-caused wasting

    1. Stella M. Hurtley

    Unique prions cause chronic wasting disease in North American elk and deer

    PHOTO: © ROBERT HARDING WORLD IMAGERY RF/ALAMY

    Chronic wasting disease (CWD) is killing deer and elk in the United States and Canada. CWD is caused by an infectious protein, or prion, that is found in meat and blood from infected animals. But is there a risk to humans who eat these animals? Kurt et al. found that mice expressing human prion protein (PrP) resisted CWD, whereas mice expressing human PrP with four elk residue substitutions were susceptible. Only two elk residue substitutions in human PrP were needed for efficient conversion of the protein to the prion conformation. The amyloid-forming propensity of the PrP was important in this conversion, which may explain why some species are highly susceptible to prions from other species.

    J. Clin. Invest. 10.1172/JCI79408 (2015).

  2. Water Quality

    More contaminants entering waterways

    1. Nicholas S. Wigginton

    Modern wastewater treatment processes still leave behind trace amounts of pharmaceuticals, personal care products, and other potentially harmful or toxic compounds. For example, over 10 metric tons of the antimicrobial compound triclosan are released from wastewater treatment plants into U.S. waterways each year. Hensley et al. detected trace contaminants in the effluent from four U.S. wastewater treatment plants, including triclosan, chlorinated triclosan derivatives, and hydroxylated by-products of polybrominated diphenyl ethers (PBDEs)—recalcitrant compounds used as flame retardants. Chlorinated triclosan derivatives were present at the same low but appreciable levels as PBDE by-products, both of which produce toxic dioxins during photodegradation.

    Environ. Sci. Water Res. Technol. 10.1039/c4ew00102h (2015).

  3. Complex Systems

    Finding communities in interacting systems

    1. Ian S. Osborne

    Understanding the underlying behavior of complex interacting systems is a challenging problem affecting the social, life, and physical sciences. Representing components of a system as nodes and assigning weights to the interactions between components can provide a graphical picture of the interacting system. Trying to map out real-life systems that are large, consist of multiple layers, and are dynamic can result in oversimplification, though. De Domenico et al. propose a method based on network flow analysis that can reveal clusters or communities of nodes that are closely connected within and across the various layers of a system. Identifying key communities in a complex interacting system could be crucial in revealing the functional structure underlying the system.

    Phys. Rev. X 5, 11027 (2015).

  4. History of Science

    Industry influence and tooth decay

    1. Barbara R. Jasny

    The most common chronic disease among children and adolescents in the United States is tooth decay. Without concerted efforts by the sugar industry, we might be a lot closer to eradication. Industry papers from 1959–1971 reveal a pattern of diverting the National Institute of Dental Research (NIDR) toward strategies to make sugar less harmful and away from reducing sweets. Kearne et al., who analyzed these papers, also found that 78% of an industry-established statement by the International Sugar Research Foundation was directly incorporated into the text of the NIDR request for research proposals for the National Caries Program in 1971.

    PLOS Med. 10.1371/journal.pmed.1001798 (2015).

  5. Plant Science

    Fish oil from plants

    1. Pamela J. Hines

    Human heart health benefits from a diet rich in the polyunsaturated fatty acids found in oily fish such as salmon and anchovies. Unfortunately, marine fisheries are increasingly fragile, and farm-raised salmon require expensive supplements to generate the desirable fatty acids. Ruiz-Lopez et al. engineered the oilseed crop plant Camelina into a source of the key fatty acids by plucking enzymes from sources as diverse as phytoplankton, microalgae, and oomycetes. Camelina expressing the transgenes made as much as a quarter of their seed lipids into replacements for fish oil, surpassing salmon, pound for pound, as a source of the right fatty acids.

    Widely grown Camelina sativa can be engineered to produce fish oil

    PHOTO: © BUITEN-BEELD/ALAMY

    Plant Biotechnol. J. 10.1111/pbi.12328 (2015).

  6. Geomorphology

    Shaping landscapes with large floods

    1. Brent Grocholski

    A large canyon in Iceland formed by an extreme flooding event

    PHOTO: E. R. C. BAYNES ET AL. PNAS 112, 8 (24 FEBRUARY 2015) © 2015 NATIONAL ACADEMY OF SCIENCES

    Extreme flood events can wreak havoc on landscapes by carving out features such as large canyons. Baynes et al. consider the multimillennial impact of extreme flood events on the erosion rate of a canyon in Iceland. By dating the canyon surfaces with cosmic rays, they find that three extreme flood events dominated background erosion processes over the past 9000 years. This is due to a transition from an erosion regime driven by abrasion to one in which basalt lava columns were toppled during the large floods. High-impact, short lived events clearly play an overriding role in this locality and may be an underappreciated force for landscape evolution.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1415443112 (2015).

  7. Psychology

    Upending our physical theories

    1. Gilbert Chin

    Learning involves defining and classification, especially when the entities in question might be actual objects, such as a glass of milk or a dove, but could also have an innate property, such as animacy. Griffiths uses the scenario of a magician transforming one type of object into another to elicit judgments about which transformations are more interesting. He finds that the direction of transformation affects these judgments, with greater interest expressed in those that move from less animacy to more; that is, changing a glass of milk into a dove rather than vice versa. This asymmetry may be due to a need to adjust our prior ideas.

    Cognition 136, 43 (2015).

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