Editors' Choice

Science  14 Nov 2014:
Vol. 346, Issue 6211, pp. 823
  1. Circadian Rhythms

    One clock for you and your microbes

    1. Lisa D. Chong
    PHOTO: © BLEND IMAGES/ALAMY

    Disrupting our circadian rhythms increases the risk of developing diabetes, obesity, cancer, and cardiovascular disease, but scientists do not fully understand why. Thaiss et al. now report that conditions that cause jet lag change the composition and activities of gut microbes in mice, which can lead to metabolic disease. Gut microbe composition no longer fluctuated diurnally in mice with disrupted circadian rhythms, but normal rhythmic feeding or the transplantation of gut microbes from normal mice restored this oscillation. Normal mice that received gut microbial transplants from jet-lagged humans or mice that experienced a change in their day-night schedule gained weight and developed symptoms of metabolic disease.

    Cell 159, 514 (2014).

  2. Biotechnology

    Aiming for a better carbon fix in plants

    1. Gilbert Chin

    Enhancing the output of Rubisco, an enzyme that converts atmospheric CO2 into energy-rich molecules, could improve photosynthetic efficiency, and therefore crop yield, in plants. Maize is a C4 grass, which uses four-carbon compounds to carry CO2 into an interior compartment; subsequent release of CO2 increases its local concentration and favors efficient activity of Rubisco. Rice, however, is a C3 grass and lacks this pathway. Wang et al. compared transcripts and metabolites in developing maize and rice plants as a step toward understanding the biochemical and anatomical bases of C4 photosynthesis. Furthermore, Lin et al. transplanted Rubisco from a cyanobacterium, which also relies on a CO2-concentrating apparatus, into tobacco (a C3 plant) chloroplasts.

    Nat. Biotech. 32, 10.1038/nbt.3019 (2014); Nature 513, 547 (2014).

  3. Climate Change Ecology

    How elevated CO2 affects grassland

    1. Andrew M. Sugden

    Experiment site in a mixed-grass prairie near Cheyenne, Wyoming.

    PHOTO: JULIE KRAY/USDA ARS IN FORT COLLINS

    Even after two decades, experiments to study the ecological effects of climate change continue to yield instructive results. Zelikova et al. studied the effects of elevated CO2 on grassland in in Wyoming over 8 years and found that the plant productivity stabilized over time. The abundance of two dominant plant species (western wheat grass and blue grama grass) decreased with elevated CO2, which led to the increased presence of subdominant species and hence greater evenness in community composition. Plant productivity stabilized as a result of such alterations community structure. This research highlights the potential for plant communities to change in the face of changing climates.

    Proc. Natl. Acad. Sci. U.S.A. 111, 15456 (2014).

  4. Superconductivity

    Describing iron-based superconductors

    1. Jelena Stajic

    In a superconducting material, pairs of electrons (the so-called Cooper pairs) flow effortlessly through the material without encountering any resistance. The energy needed to break up a Cooper pair is called the superconducting gap. Since their discovery several years ago, iron-based superconductors (IBSs) have puzzled researchers because different IBS families appear to have different gap symmetries. Yin et al. used first-principles calculations to explore the nature of superconductivity in a large number of IBS compounds. They found that three related types of symmetry occurred in different IBS families, including a variant that hadn't been discussed previously. A comparison with experimental data for the compound LiFeAs suggests that the gap in this material has this particular symmetry.

    Nat. Phys. 10, 845 (2014).

  5. Open innovation

    Sharing results midway or at the end

    1. Brad Wible

    Technological innovation depends on striking a balance between sharing discoveries to spur follow-on development and ensuring that too much sharing does not undercut incentives to participate. Boudreau and Lakhani randomized an online bioinformatics algorithm contest in order to examine the consequences of intermediate and final disclosure. Finaldisclosure (FD) solvers had no in-group communication, whereas intermediate-disclosure (ID) solvers could share intermediate solutions. Fewer people opted to participate in ID, they submitted fewer solutions per person, and they tried fewer unique approaches. However, ID approaches clustered together conceptually and smoothly improved more quickly over time, whereas FD had much more variable quality and didn't achieve the mean or peak performance levels shown in ID.

    Res. Policy 10.1016/j.respol.2014.08.001 (2014).

  6. Biofuels

    A team effort to get more out of lignin

    1. Jake Yeston

    You've probably heard about cellulosic biofuels—fuels manufactured from the sugars trapped in plants' cellulose, which is largely inedible (for humans anyway). As commercial efforts in this arena get off the ground, chemists are rushing to solve a related problem: how to transform and market the woody lignin material that comes along with the cellulose. Linger et al. demonstrate the advantages of combining chemical and microbial protocols. First, treatment with base breaks the lignin down into a diverse set of molecules. Then Pseudomonas putida bacteria are put to work channeling these molecules into a more uniform product stream of (poly)-hydroxyalkanoates. After that, synthetic chemistry transforms this stream into plastics, liquid fuels, and commodity compounds.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1410657111 (2014).

  7. Tissue Repair

    A conserved response for tissue repair

    1. Beverly A. Purnell

    Upon injury or infection, the body releases chemicals that trigger tissue repair and pathogen clearance. Because the medical community needs new therapeutic leads in this era of growing antibiotic resistance, identifying these molecules is a high priority. Dalli et al. looked for these factors in mice infected with self-resolving Escherichia coli, in human breast milk, and in regenerating planaria. They identified two related molecules, conserved across these organisms, which promoted pathogen clearance, reduced inflammation, and accelerated tissue regeneration. Scientists will need to carry out further studies to determine whether these chemicals have similar properties in humans.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1415006111 (2014).

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