Editors' Choice

Science  16 Sep 2016:
Vol. 353, Issue 6305, pp. 1246
  1. Ecophysiology

    Wake up!

    1. Sacha Vignieri

    The smell of fire rouses Eastern pygmy possums from torpor.

    PHOTO: DAVE WATTS/VISUALS UNLIMITED

    Torpor occurs when an endothermic animal's core body temperature is reduced below a critical threshold. Similar to hibernation, torpid animals' physiological and neural systems have reduced activity in this energy-saving state. Generally, it is thought that animals in this condition have little ability to respond to threats. Nowack et al. show, however, that Eastern pygmy possums were roused from torpor by the smell of fire, in some cases completely emerging and initiating directed climbing. Though this movement occurred well below suboptimal body temperature, animals were not able to move at the coldest temperatures. These results show that torpid animals may be able to respond to threats, especially gradual ones, such as fire, but that ambient temperature is a key driver of their ability to do so.

    Sci. Nat. 10.1007/s00114-016-1396-6 (2016).

  2. Brain Connections

    How the mind controls the body

    1. Peter Stern

    Can our brain influence our internal organs? Dum et al. used retrograde transneuronal transport of rabies virus to identify the brain regions that project to a part of the adrenal gland called the medulla. Two networks are the major sources of neuronal input to this organ, which plays an important role in dealing with physical and emotional stress. One network includes the primary motor cortex and specific regions in the frontal lobe of the brain. The other network involves distinct parts of the anterior cingulate cortex, an area that regulates cognition and emotion. The central commands that control the adrenal medulla originate from brain regions that are involved in multiple functions, including body movement, cognitive control, and affective processing.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1605044113 (2016).

  3. Mitochondrial Genetics

    Effects of mtDNA and nuclear genetic variation

    1. Laura M. Zahn

    Because mitochondrial DNA (mtDNA) is predominately inherited through the mother, it is hypothesized that in the case of mtDNA mutations, males might be more affected by genetic incompatibilities. Examining mtDNA and nuclear variation and interactions in fruit flies, Mossman et al. show both genotype- and sex-specific effects on gene expression. Effects on gene expression profiles were greater in females for all examined genetic differences, suggesting that females are more sensitive to genetic variation. In contrast, a greater number of genes exhibited some effects in males, but the degree of difference was lower and not significant relative to the impacts of genetic variation in females.

    Genetics 10.1534/genetics.116.192328 (2016).

  4. Diversity

    Mentoring as value added

    1. Melissa McCartney

    The benefits of faculty-mentored undergraduate research experiences are well known. Interinstitutional research training programs ensure that these opportunities are available to all science, technology, engineering, and math students, but how do you convince faculty to mentor undergraduates from other institutions? Morales et al. surveyed faculty members at 13 U.S. institutions to identify factors leading to their willingness to mentor undergraduate students from other universities and the incentives that they value most in return. Increasing diversity was the main motivation for faculty participation, although incentives varied based on faculty career stage and funding status. Overall, results suggest that promoting faculty awareness of the positive impacts of mentoring students from underrepresented backgrounds and/or underresourced institutions, especially in terms of increasing diversity, would increase faculty engagement.

    CBE Life Sci. Educ. 10.1187/cbe.16-01-0039 (2016).

  5. Ceramics

    Probing the boundaries of ceramics

    1. Brent Grocholski

    Ceramics are important but underappreciated materials for numerous technologies. Diercks et al. investigate the connection between electrical properties and local chemistry in neodymium-doped ceria. They show that macroscopic changes in properties such as electrical conductivity are tied to the chemical composition of the grain boundaries, which make up a tiny fraction of the overall volume. High-precision maps provide a method for understanding the relationship between microscopic and macroscopic properties, which can be exploited for optimizing materials design.

    J. Mater. Chem. A 10.1039/c5ta10064j (2016).

  6. Aging

    Regeneration of NAD keeps mouse muscles young

    1. Bryan L. Ray

    Evidence for a critical role of nicotinamide adenine dinucleotide (NAD) metabolism in aging is accumulating. Frederick et al. studied mice with muscle-specific depletion of nicotinamide phosphoribosyltransferase (Nampt), an enzyme needed to restore concentrations of NAD in working muscle. Muscle in young animals tolerated a large reduction in the amount of NAD without obvious loss of function. However, older control animals had decreased muscle concentrations of NAD, which correlated with decreased performance, and these effects were more pronounced in animals lacking Nampt. Restoration of NAD concentrations by feeding older animals nicotinamide riboside partially restored muscle function. Accordingly, overexpression of Nampt in muscle helped prevent the age-dependent decline in muscular function. Thus, maintenance of proper NAD metabolism in muscle appears to be needed for sustained function.

    Cell Metab. 10.1016/j.cmet.2016.07.005 (2016).

    Correction (3 October 2016): This Week in Other Journals, "Regeneration of NAD keeps mouse muscles young" (16 September 2016, p. 1247). An error was introduced during the production process. The definition of the acronym NAD should be nicotinamide adenine dinucleotide. The HTML and PDF have been corrected.

  7. Microbiology

    Grown in the land of the ice and snow

    1. Nicholas S. Wigginton

    Glaciers and ice fields on the west coast of Spitsbergen, Svalbard, Norway

    PHOTO: OBERTHARDING/ALAMY STOCK PHOTO

    Although seemingly inhospitable, glaciers host a range of microbial activities. Algal blooms are common on the surfaces of snow and ice, for example, which can lower albedo and increase melting. Lutz et al. identified the algal communities, along with archaea and bacteria, on 12 glaciers and permanent snowfields in Norway and Sweden. Correlations between nutrient ratios and metabolite production point to commonalities in community function between sites. The synthesis of some darkening carotenoid compounds, for example, is critically dependent on the availability of nitrogen. If atmospheric nitrogen deposition increases as expected, more frequent algal blooms may lead to more glacial melting.

    Environ. Microbiol. 10.1111/1462-2920.13494 (2016).

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