Editors' Choice

Science  19 Aug 2016:
Vol. 353, Issue 6301, pp. 787
  1. Human Conflict

    Climate disasters in conflict-prone regions

    1. Andrew M. Sugden

    Climate deterioration may exacerbate conflict in war-torn, arid regions.

    PHOTO: SIPPL SIPA USA/ASSOCIATED PRESS

    Does climate change have the potential to enhance the risks of conflict in human societies? Stroessner et al. studied patterns of conflict outbreaks and climate-related disasters in ethnically divided countries between 1980 and 2010. Almost one-quarter of conflicts coincided closely with climatic extremes, particularly drought. Affected regions included North Africa, the Levant, Syria, and Afghanistan. Although the patterns are largely correlational and the local and regional circumstances varied, the study suggests that climate deterioration may exacerbate societal instability in the affected regions.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1601611113 (2016).

  2. Vaccine Development

    Single serotype for Zika

    1. Lisa D. Chong

    Zika virus strains are of either African or Asian genetic lineage, and Asian strains are the cause of the outbreak in Central and South America. Dowd et al. report that natural antibodies produced by individuals infected with the presently circulating Asian strains can neutralize viruses from either lineage. This indicates a single Zika viral serotype and suggests that a single-strain vaccine could be broadly protective against diverse strains of Zika. Antibodies elicited by Zika virus target the envelope protein of the virion, for which the two genetic lineages share >95% amino acid identity.

    Cell Rep. 10.1016/j.celrep. 2016.07.049 (2016).

  3. Materials Science

    Tunable materials switching with light

    1. Marc S. Lavine

    Composite materials incorporate weak, stretchy, energy-absorbing materials between sheets of strong, brittle ones. Adaptive materials can locally repair or tune themselves in response to an external stimulus such as light. Zhu et al. combined these ideas into a nacre-mimetic nanocomposite built from a nanoclay, a polymer, and a small amount of reduced graphene oxide (rGO). The polymer includes thermally reversible hydrogen-bonding motifs, whose interlinking determines whether the nanocomposite is very stiff and strong or stiff and ductile. On irradiation with near-infrared light, the rGO controllable heats the polymer, making it possible to switch a single material between these states.

    Scanning electron micrograph of a cross section of a nacre-mimetic nanocomposite

    PHOTO: MANFRED RUCKSZIO / ALAMY STOCK PHOTO

    Nano Lett. 10.1021/acs. nanolett.6b02127 (2016).

  4. RNA Editing

    Selection may influence transcriptional variation

    1. Laura M. Zahn

    Posttranscriptional modifications, including changing an adenosine (A) to an inosine (I), may affect the translation of RNA transcripts into proteins. Yu et al. examined the extent and conservation or divergence of A-to-I editing across the genomes of seven Drosophila species. Editing occurred most commonly as nonconserved events observed only in a single gene from a gene family within a species. Positive selection was identified in cases where multiple genes within a gene family were edited across species; these also showed enrichment for function in the neural system. This suggests that editing may be selected for developmental variation.

    PLOS Genet. 10.1371/journal. pgen.1006191 (2016).

  5. Plant Science

    Transferring a bioactive

    1. Pamela J. Hines

    Once only found in small hairs on sweet wormwood plants, artemisinin can now be produced by tobacco plants.

    PHOTO: MANFRED RUCKSZIO / ALAMY STOCK PHOTO

    Artemisinin, which is critical in defense against malaria, was originally found in tiny hairs on the surface of leaves of the plant Artemisia annua. But this source plant does not support a sufficiently stable supply of artemisinin for worldwide use. Fuentes et al. have developed a synthetic biology approach termed COSTREL (combinatorial supertransformation of transplastomic recipient lines) that produces the immediate precursor of artemisinin, artemisinic acid, in widely cultivated tobacco (Nicotiana tabacum cv. Petit Havana). The first stage of COSTREL involves transformation of tobacco chloroplasts with genes encoding the core enzymes of the artemisinin biosynthetic pathway. With that pathway established, the second stage involves combinatorial nuclear transformation to superimpose genes that regulate flux through the biosynthetic pathway. A transformation mix supports selection of the most optimal gene combination. The resulting tobacco plants produce artemisinic acid at up to ~4.8 kg per acre.

    eLife 10.7554/eLife.13664 (2016).

  6. Organic Chemistry

    A light approach to diverse amino acids

    1. Jake Yeston

    As the building blocks of all proteins, amino acids have long been a target of modification for chemists. Installing unnatural side chains can facilitate medicinal research, as well as fundamental studies of protein function and dynamics. Jiang et al. present a versatile method for replacing the natural side chains of aspartic and glutamic acid with a variety of ketones, esters, amides, and alkynes while preserving the original stereochemistry. A ruthenium catalyst excited by visible light spurs ejection of a phthalimide-activated acid group from the original side chain, leaving a reactive radical to bind the new substituent.

    Sci. Rep. 10.1038/srep26161 (2016).

  7. Diversity

    The physics of a gender gap

    1. Melissa McCartney

    Women are underrepresented at all levels of physics, even though the number of girls taking physics classes in U.S. high schools is increasing. Lock and Hazari examined the relationship between gender narratives and who students believe can be a physicist. They analyzed documentation of the classes of one high school teacher who engaged students in discussions on the underrepresentation of women in physics, along with student and teacher interviews and relevant student work, for possible mechanisms connecting these discussions to an increase in physics identity for female students. They found that the discussions created an opportunity for students' views of professional and school science to change, which may subsequently enable a shift in physics identity development among female students.

    Phys. Rev. Phys. Educ. Res. 10.1103/PhysRevPhysEducRes.12.020101 (2016)

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