Editors' Choice

Science  21 Oct 2016:
Vol. 354, Issue 6310, pp. 298
  1. Reproductive Biology

    Somatic cells raise sperm barriers

    1. Sarah E. Harrison

    Testes cells block sperm reentry with actin.

    PHOTO: DR. DAVID PHILLIPS/VISUALS UNLIMITED, INC.

    Sperm release is a potential target for contraception. Using time-lapse studies of sperm release from Drosophila testes ex vivo, Dubey et al. found that spermatid tails are released from the testes before the heads. Before ejection, spermatid heads attempt to penetrate the somatic cells of the testes but are repelled. Localized actin nucleation in the cortex of the somatic cell generates a mechanical barrier, preventing invasion. This response has similarities to the regulation of sperm release in mammals.

    Dev. Cell 38, 507 (2016).

  2. T Cell Memory

    Priming for T cell memory in tissues

    1. Kristen L. Mueller

    During infections, dendritic cells prime T cell immunity and drive a subset of T cells to become long-lived memory cells. Memory T cells come in two flavors: those that circulate and those that establish long-term residency in tissues (Trm). Iborra et al. investigated the priming requirements of each type of cell in mice. Direct antigen presentation by dendritic cells is sufficient for generating circulating memory CD8+ T cells. In contrast, CD8+ Trm cells require antigen cross-presentation by dendritic cells that express DNGR-1, a protein receptor that binds necrotic cells. Without either DNGR-1 or cross-presenting dendritic cells, mice form few Trm cells in response to viral infection.

    Immunity 10.1016/j.immuni.2016.08.019 (2016).

  3. Energy Efficiency

    Better buildings' appetites for energy

    1. Brad Wible

    Building codes targeting energy efficiency may not lead to obvious reductions in energy consumption, particularly compared with optimistic engineering predictions made before enacting the codes. Levinson studied homes in California where, since 1978, increasingly ambitious building regulations have targeted energy efficiency. But after controlling for factors such as home size, location, and occupant demographics; measuring consumption responses to temperature changes; and comparing with consumption in other states, newer homes built to me et California's stricter standards used no less energy than older ones. Although no direct impact on energy consumption was observed, the codes may have still had benefits, such as allowing residents to stay more comfortably warm or cool for a given amount of energy consumption and corresponding greenhouse gas emissions.

    Amer. Econ. Rev. 10.1257/aer.20150102 (2016).

  4. Materials Science

    Breaking the strongest of bonds

    1. Brent Grocholski

    Boron carbide is an extremely hard ceramic used for applications such as bulletproof vests. Its exceptional properties are due to the bond strength in boron-carbon chains and clusters. Xie et al. show that the boron-carbon bond isn't quite as unbreakable as it may seem. The researchers found evidence for the complete destruction of 12-atom boron carbide clusters during laser-assisted evaporation while performing atom probe experiments. This result defies the expectation that these clusters are hard to break and may help explain the decrease in ballistic performance at high impact rates.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1607980113 (2016).

  5. Microporous Compounds

    Creating a polybenzene network

    1. Phil Szuromi

    Metal-organic framework (MOF) compounds are microporous materials in which inorganic centers are linked with organic ligands. Some network topologies, such as the diamond lattice, are formed by many MOFs, whereas others require specific linker positioning. One of the most difficult to form is the polybenzene (pbz) network that results from connecting phenyl rings via single carbon-carbon bonds into a three-dimensional network. Alezi et al. show that a six-connected hexagonal zirconium(IV) cluster can link a hexagonal ligand (a phenyl group substituted with carboxylate-terminated biphenyl groups) to form a pbz network. Structural studies verified an appropriate dihedral angle (70.5°) between the central phenyl ring of the linker and the hexagonal zirconium center. The material is not high-porosity but achieves high uptakes of methane at high pressures.

    Cartoon of a zirconium-based metal-organic framework with the polybenzene (pbz) structure

    PHOTO: DUBEY ET AL., DEVELOPMENTAL CELL 38 (12 SEPTEMBER 2016) © CELL PRESS

    J. Am. Chem. Soc. 10.1021/jacs.6b08176 (2016).

  6. Cancer Therapy

    A hat trick for differentiation therapy?

    1. Paula A. Kiberstis

    Most forms of acute myeloid leukemia (AML) are associated with a poor prognosis. One exception is acute promyelocytic leukemia, which is largely curable by two drugs, one originating from traditional Chinese medicine. Both drugs act by forcing leukemic precursor cells to differentiate into mature cell types that no longer divide. Given that all forms of AML are characterized by preleukemic myeloid cells whose differentiation is arrested, Sykes et al. performed an unbiased screen for compounds that induce myeloid differentiation. Unexpectedly, the most active compounds in mouse and human models were inhibitors of dihydroorotate dehydrogenase, an enzyme involved in pyrimidine biosynthesis. These inhibitors slowed AML development in mice and thus may merit further study as a therapy for the human disease.

    Cell 167, 171 (2016).

  7. Neuroscience

    Explaining gender differences in anxiety

    1. L. Bryan Ray

    Differences in the way brain neuronal circuits respond to the hormone oxytocin can explain gender-dependent variation in behavior. Li et al. found that a set of oxytocin-responsive neurons are anatomically similar in both sexes, but in males, they secrete a protein that antagonizes the effect of the stress-associated corticotropin-releasing hormone. This interaction provides an anti-anxiety effect with oxytocin that is not seen in females. Such signaling differences could underlie sex-dependent differences in social or emotional disorders and may reveal new mechanisms for therapeutic intervention.

    Cell 10.1016/j. cell.2016.08.067 (2016).

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