Editors' Choice

Science  13 Jul 2018:
Vol. 361, Issue 6398, pp. 142
  1. Microbiota

    Cell-to-cell action in cholera

    1. Caroline Ash

    The pathogenicity of Vibrio cholerae (illustrated at left) is reduced by removal of a commensal bacterium.

    CREDIT: KTSDESIGN/SCIENCE SOURCE

    Gut bacteria are competitive. They jostle for niches and nutrients by means of a variety of mechanisms. Gram-negative bacteria devote a lot of resources to the comparatively large (up to 600 nm) type 6 secretion system (T6SS) used to stab neighboring bacterial and host cells. Contrary to expectations, Fast et al. discovered that commensal bacteria are not always protective against T6SS-toting pathogens. Vibrio cholerae T6SS contributes to host death in the fly model of cholera. Acetobacter pasteurianus is a common, normally harmless, commensal in the fly gut. If A. pasteurianus is removed, surprisingly, V. cholera is enfeebled, too. This effect seems to be mediated by signaling through the immune deficiency (IMD) pathway of the fly. The IMD is “primed” by the commensal organism.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1802165115 (2018).

  2. Emerging Therapies

    Gene editing gets a head start

    1. Paula A. Kiberstis

    The development of gene-editing technologies into therapies for human disease is an exciting prospect. A crucial question is whether there are advantages to correcting disease-causing mutations before rather than after birth, and whether this approach is even feasible. In a proof-of-concept study in mice, Ricciardi et al. accomplished successful in utero correction of a hemoglobin gene mutation that causes β-thalassemia, a serious blood disorder. They injected nanoparticles containing gene-editing machinery (triplex-forming peptide nucleic acids and single-stranded donor DNA) intravenously into midgestational mouse fetuses. After birth, the treated mice showed sustained amelioration of anemia and survived longer than untreated mice.

    Nat. Commun. 10.1038/s41467-018-04894-2 (2018).

  3. Cancer

    Finding the precise drug

    1. Gemma Alderton

    Treating cancer according to the molecular makeup of tumor cells is challenging. How can we find a target that will kill tumor cells and match it to an effective drug? Alvarez et al. analyzed the protein-signaling networks in human gastroenteropancreatic neuroendocrine tumors (GEP-NETs) to find master regulators of tumor survival. Subsequent screening of GEP-NET–derived cells with various drugs confirmed that their top hit, entinostat, inhibited GEP-NET growth in vivo. This approach has the potential to provide unbiased precision therapy for many cancers, especially rare cancers, such as GEP-NETs.

    Nat. Genet. 10.1038/s41588-018-0138-4 (2018).

  4. Quantum Optics

    Single photons for optic fibers

    1. Ian S. Osborne

    Schematic illustration of silicon waveguides and a YSO crystal

    ILLUSTRATION: A. M. DIBOS ET AL., PHYS. REV. LETT. 120, 243601 (2018)

    Being robust, fast, and able to encode information in a number of different ways, single photons are ideal carriers of quantum information. Exploiting the vast optic fiber network to route single photons between distant points, however, is hampered by the lack of single-photon sources operating at telecom wavelengths. Dibos et al. show that single erbium ions doped in a solid-state host material produce single photons at just the right wavelength for long-distance transmission. They use a silicon-based nanophotonic crystal in close proximity to a doped ion to enhance the extraction of single photons and to couple them in an optic fiber. The results demonstrate the basis of an architecture to develop long-distance quantum optical networks.

    Phys. Rev. Lett. 120, 243601 (2018).

  5. Cell Biology

    mTORC1 jams cell traffic

    1. L. Bryan Ray

    The cytoplasm of a cell is stuffed with large molecules and organelles. Such crowding may cause some molecules to aggregate, which could in turn affect their biological function. To monitor cytoplasmic crowding, Delarue et al. made a probe from bacterial proteins that form large scaffolds linked to fluorescent proteins. In yeast and human cells, the probes revealed that the protein kinase complex mTORC1 (mechanistic target of rapamycin complex 1) enhanced cytoplasmic viscosity. It did so by increasing production of ribosomes while inhibiting their degradation. Because ribosomes occupy about 20% of a cell's volume, mTORC1 activity tunes cytoplasmic crowding and thus influences cell physiology.

    Cell 10.1016/j.cell.2018.05.042 (2018).

  6. Carbon Capture

    Help wanted

    1. H. Jesse Smith

    Preventing global surface air temperatures from rising too high will require emissions to be reduced and CO2 to be removed (captured) from the air. Many ways to do this have been proposed, although none to date are both technologically and economically feasible, so new and better strategies are needed. Rau et al. suggest that generating H2 with a combination of saline water electrolysis and mineral weathering, powered by electricity not derived from fossil fuels, could greatly increase energy generation and CO2 removal, at a lower cost than methods involving biomass energy plus carbon capture and storage. This approach also would allow carbon to be sequestered as long-lived ocean alkalinity rather than as concentrated CO2.

    Nat. Clim. Change 8, 621 (2018).

  7. Thermoelectrics

    Lower symmetry for higher performance

    1. Brent Grocholski

    Thermoelectric materials interchange heat and electricity. Lowering thermal conductivity while maintaining electrical conductivity is important for developing promising thermoelectric materials. Li et al. depart from the usual strategy of using high-symmetry materials by moving from cubic to rhombohedral GeTe, which ends up boosting the thermoelectric performance. The performance metric called the figure of merit is 2.4 at 600 K. The general strategy may be applicable to other materials, providing another pathway to improve performance.

    Joule 2, 976 (2018)

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