Editors' Choice

Science  08 Jul 2016:
Vol. 353, Issue 6295, pp. 134
  1. Microbiology

    A viral blight on ocean sunshine sugars

    1. Guy Riddihough

    Viruses can affect the metabolism of cyanobacteria.

    PHOTO: STEVE GSCHMEISSNER/SCIENCE SOURCE

    Essentially all organic material derives from photosynthesis. The most numerous photosynthetic organisms are marine picocyanobacteria, which synthesize about 10% of Earth's organic compounds. Even more numerous marine viruses prey on picocyanobacteria. Putty et al. show that the infecting viruses subvert the metabolism of their picocyanobacteria hosts, boosting the energy-producing reactions of photosynthesis to support viral infection. At the same time, they inhibit the ability of picocyanobacteria to fix CO2 and synthesize organic material, therefore having a potentially substantial effect on global amounts of organic compounds.

    Curr. Biol. 10.1016/j.cub.2016.04.036 (2016).

  2. Thermal Management

    Silica surfaces send the heat away

    1. Brent Grocholski

    Dissipating the ever-increasing heat from electronics requires developing materials with high thermal conductivities. Tervo et al. found, through a series of experiments, that packed silica nanoparticle beds coated with different coolant fluids have greatly enhanced thermal conductivity. The increase may be due to the surface properties of the nanoparticles, which are driven by strong surface electrical polarization. This new approach for modulating thermal conductivity presents new opportunities for thermal management.

    Mater. Horiz. 10.1039/c6mh00098c (2016).

  3. Neurobiology

    Even more pain in opioid treatment

    1. L. Bryan Ray

    Amid heightened concern about the addictive properties of opiates used to manage pain, new results from Grace et al. reveal that morphine can actually promote chronic pain. Rats with nerve damage treated for 5 days with morphine showed a sensitization to pain that persisted for months after opioid treatment was stopped. Neuronal opioid receptors did not contribute to this effect. Rather, opioids caused the increased pain by heightening inflammatory signaling in macrophage-like cells called microglia that reside in the spinal cord and brain. On the positive side, specific targeting of the inflammatory signaling in microglia may block the long-term pain-inducing effects of opioids, while still allowing their short-term analgesic effects.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1602070113 (2016).

  4. Organic Chemistry

    Carboxylating stubborn alkyl chlorides

    1. Phil Szuromi

    The utility of alkyl chlorides and carbon dioxide (CO2) as reagents in organic synthesis is often limited by the difficulty of activating these molecules. Börjesson et al. have overcome both these challenges with a nickel catalyst that adds CO2 at ambient pressures to unactivated alkyl chlorides (primary, secondary, and even tertiary). The nickel catalyst ligands that were most effective at minimizing side reactions were 1,10-phenanthrolines with ortho-substituents. The nickel center displaced chloride to create a nucleophile that could then react with electrophilic CO2. The reaction is tolerant of aliphatic alcohol or phenol groups, which helps minimize the need for protecting groups.

    J. Am. Chem. Soc. 10.1021/jacs.6b04088 (2016).

  5. Antiviral Immunity

    Breathing life into the antiviral response

    1. Kristen L. Mueller

    Fighting viruses requires a coordinated attack. Immune cells known as plasmacytoid dendritic cells (pDCs) lie at the heart of the response and, among other functions, secrete large amounts of antiviral proteins called type I interferons (IFNs) that alert the body that it is under attack. Wu et al. report that in addition to eliciting expression of a suite of antiviral genes, type I IFNs also cause cells to modify their metabolism. Type I IFNs signal cells to shift their metabolism toward fatty acid oxidation and oxidative phosphorylation, both in pDCs and in other cell types such as T cells and epithelial cells. Antiviral functions of pDCs required these metabolic changes, and viral clearance in mice required fatty acid oxidation.

    Immunity 44, 1325 (2016).

  6. Human Genetics

    Genetics of the great migration

    1. LZ

    Slavery shaped the genetic diversity of African Americans.

    CREDIT: “THE GOOBER-GATHERERS,” 1890 (ENGRAVING), BRADLEY, HORACE (FL. 1890)/PRIVATE COLLECTION/PETER NEWARK AMERICAN PICTURES/BRIDGEMAN IMAGES

    The African American population is underrepresented in genetic studies, and their history of slavery, systemic discrimination, and migration probably shaped their genetic diversity. To better understand this, Baharian et al. analyzed the genetic variation in 3736 individuals from three cohorts representing the diversity of African Americans across the United States. These data identified historical events in the movement and admixture (interbreeding of isolated groups) of African Americans, including the fact that about 1.2% of their ancestry is Native American, which probably traces back to the early period of slavery. Overall, the data illustrate how differences in social opportunity over centuries can shape the genetic diversity of a population.

    PLOS Genet. 12, e1006059 (2016).

  7. Quantum Optics

    How a particle gets its quantum kicks

    1. Ian S. Osborne

    The radiation pressure from a focused laser beam used to cool and trap particles is the basis for advanced optical tweezing methods that have found a diverse range of applications in biology, chemistry, and physics. When a trapped particle is subjected to a force, it shifts its position in the trap, thereby providing the possibility of sensing that force. By confining a 50-nm-diameter silica bead in an ultrahigh vacuum, Jain et al. isolated the particle from environment-induced jiggling and effectively restricted the particle's motion to that due to quantum optical forces. They then showed that they can measure the recoil rate of photons from the particle, providing the possibility of exploiting the effect for highly sensitive force measurements.

    Phys. Rev. Lett. 116, 243601 (2016).