Editors' Choice

Science  15 Sep 2017:
Vol. 357, Issue 6356, pp. 1109
  1. Neurodevelopment

    Migration bound to neurotransmitter

    1. Pamela J. Hines

    Homeobox genes control interneuron migration and GABA production.

    CREDIT: PHILIP GARDNER

    Interneurons in the brain that use GABA (γ-aminobutyric acid) as a neurotransmitter are essential for functional circuits. During development, these interneurons migrate tangentially from their birthplace in embryonic ganglionic eminences to their functional homes in the neocortex. In mice lacking the distal-less homeobox genes (Dlx1 and -2), this migration is disrupted. Studying mouse brain development, Le et al. now show that Dlx1 and -2 regulate not only interneuron migration but also production of GABA. These genes bind to and regulate promotors of genes encoding GAD (glutamic acid decarboxylase), which converts the excitatory neurotransmitter glutamate into the inhibitory neurotransmitter GABA.

    J. Neurosci. 10.1523/JNEUROSCI.2125-16.2017 (2017).

  2. Microbiome

    Inflammasomes and gut flora

    1. Priscilla N. Kelly

    A large proportion of our immune system resides in the gut. Inflammasomes are host molecular complexes that sense danger and activate immune responses to food-related signals and foreign pathogens. Studies in mice have suggested that Nlrp6-ASC inflammasomes influence gut flora composition and susceptibility to obesity, colon inflammation, and fatty liver disease. Mamantopoulos et al. analyzed the microbiome of Nlrp6- or ASC-deficient mice and littermate siblings containing functional copies of the encoding genes. The study compared mouse cohorts housed in two separate animal facilities in different countries. The authors found that, in contrast to previous reports, Nlrp6- and ASC-mediated inflammasome signaling may not affect immunity or shape gut flora.

    Immunity 10.1016/j.immuni.2017.07.011 (2017).

  3. Metabolism

    Staying warm requires communication

    1. Paula A. Kiberstis

    Communicating lipids are released from adipocytes during cold exposure.

    CREDIT: STEVE GSCHMEISSNER/SCIENCE SOURCE

    Mammals cope with falling temperatures by undergoing a series of metabolic changes, some of them poorly understood. In mice, Simcox et al. identified a previously unappreciated intertissue communication system that mobilizes energy for heat production. The molecular linchpins of this system are liver-derived serum lipids called acylcarnitines. Liver production of acylcarnitines increases at low temperatures because factors critical to their synthesis, free fatty acids, are released from white adipocytes upon cold exposure. Circulating acylcarnitines are then taken up by brown adipose tissue, which uses them as a fuel source for heat generation. Aging in mice is associated with increased cold sensitivity, and, interestingly, administration of molecules that enhance acylcarnitine synthesis reversed this sensitivity.

    Cell Metab. 10.1016/j.cmet.2017.08.006 (2017).

  4. Biomaterials

    Ways to patch a broken heart

    1. Marc S. Lavine

    Minimizing how invasive a surgical procedure is can benefit the patient, and the same could be true for the delivery of transient patches to help repair damaged tissues. Montgomery et al. designed optimal scaffolds from biodegradable poly[octamethylene maleate (anhydride) citrate] that were confined in bioreactors in their extended shape while seeded with cells. Patches as large as a square centimeter could then be compressed and delivered through an orifice a millimeter wide to repair rat hearts, where the residual stress from the injection process causes the scaffold to return to its original shape, but without damaging the cells. Further tests showed the successful delivery of patches to porcine epicardium, aorta, and liver.

    Nat. Mat. 10.1038/nmat4956 (2017).

  5. Stellar Astrophysics

    An yttrium dating method for giant stars

    1. Keith T. Smith

    A biodegradable scaffold emerging from a 1-mm capillary glass pipette

    CREDIT: MILES MONTGOMERY AND RICK LU

    The elements yttrium and magnesium are produced by different types of supernovae, so their abundance ratio can be used to date the formation of solar-type dwarf stars. Slumstrup et al. investigated whether the method also works for more evolved giant stars. They obtained spectra of giant stars in four open clusters, whose ages are known by other means, to calibrate the relation. They found that the giant stars follow the same trend of Y/Mg versus age as the dwarf stars—at least when the abundance of iron is moderately high. Because giant stars are much brighter than dwarfs, this technique may be used to date individual stars that are further away from Earth.

    Astron. Astrophys. 604, L8 (2017).

  6. Education

    The math behind quantitative success

    1. Melissa McCartney

    Better integration of math and biology is a long-standing goal of STEM (science, technology, engineering, and mathematics) education. A parallel long-standing challenge has been overcoming students' negative attitudes toward math. How can educators better align their curricula to student math-biology values? Andrews et al. developed the Math-Biology Values Instrument (MBVI), an 11-item college-level self-report tool based on expectancy-value theory, to measure students' interest in using math to understand biology. Life science educators can use MBVI at the beginning of a course to gauge their students' attitudes toward math, allowing for appropriate integration of quantitative skills into the curriculum. The MBVI can also be used by researchers assessing the success of quantitative biology reforms as a way to measure increased positive attitudes toward math.

    CBE Life Sci. Educ. 10.1187/cbe.17-03-0043 (2017).

  7. Synthetic Biology

    Synthetic ecosystems

    1. Laura M. Zahn

    Natural ecosystems can be difficult to study because of the many interactions among organisms. In the laboratory, experimental systems often can only examine a small subset of organisms, which may not represent the true nature of the larger community. To get around these limitations, Amor et al. engineered microbes that are required to exchange amino acids and used them to create synthetic ecosystems representing multiple states of cooperation and parasitism. With these tools, they were able to model and support hypotheses of how stable mutualisms can arise and identify when populations are vulnerable to parasitism. Although the field of synthetic ecosystems is relatively new, the authors suggest that future work can be used to identify and bioengineer environments, such as agricultural soil microbiomes.

    PLOS Comput. Biol. 10.1371/journal. pcbi.1005689 (2017).