Editors' Choice

Science  26 Feb 2016:
Vol. 351, Issue 6276, pp. 930
  1. Evolutionary Genetics

    How new wing patterns evolve

    1. Laura M. Zahn

    Amazonian Heliconious butterflies show incredible diversity in wing patterning


    Butterflies show enormous diversity in wing patterning, so much so that many species can be identified by their wing patterns alone. Differences in gene expression underlie pattern variation between closely related species. To better understand this, Wallbank et al. examined the genetic elements that control the expression of optix, which encodes a transcription factor that determines red patterning in Amazonian Heliconious butterflies. The authors identified two distinct genetic regions that affect optix expression and hence the pattern of colors on the wing. These elements appear to have evolved in separate species but were brought together when these species hybridized, demonstrating that regulatory elements introduced by new species can cause phenotypes to evolve.

    PLOS Biol. 14, e1002353 (2016).

  2. Stellar Evolution

    Red giants can get dusty with age

    1. Keith T. Smith

    When a low-to-intermediate-mass star exhausts the hydrogen in its core, its temperature and luminosity evolve in a wellknown sequence. During the post-asymptotic giant branch (post-AGB) stage, the star throws of its outer layers, forming copious amounts of dust. Kamath et al. have found a previously unrecognized group of stars whose evolution seems to have been interrupted at the earlier red giant branch (RGB) stage, appearing as dusty “post-RGB” stars. They speculate that these stars may form in a binary system, either by a companion stripping of the outer layers of the star before it reaches the AGB, or by the two stars merging.

    Astron. Astrophys. 586, L5 (2016).

  3. Optics

    Polarimetry takes to a new plane

    1. Ian S. Osborne

    Polarimetry involves the measurement of polarization of light. Polarization can be used in characterization of a material, in remote sensing applications, or even as a degree of freedom for the encoding of information in an optic fiber. Determining the polarization of an optical signal typically involves bulk optical components such as lenses, beam splitters, and birefringent crystals; which can quickly become unwieldy for complex optical applications. Mueller et al. take a nanophotonics approach, which uses patterned planar arrays of subwavelength metal antennas, or metasurfaces, designed to scatter light, depending on the specific polarization properties of the light. The demonstration should pave the way for ultracompact on-chip polarimetry applications in sensing, characterization, and optical communication.

    Optica 3, 42 (2016).

  4. Ecology

    It's tough for life on a plastic planet

    1. Guy Riddihough

    Microplastics threaten Pacific oysters


    We dump an estimated 4 to 12 million tons of plastic waste into the oceans every year. This plastic breaks down into tiny pieces called microplastic particles, which can be ingested by marine life, causing unknown effects. To assess the impact of microplastic particles, Sussarellu et al. exposed Pacific oysters to polystyrene microspheres. The oysters efficiently ingested the microspheres but to ill effect. The microspheres interfered with their digestion and affected fecundity, lowering egg and sperms counts. Some negative effects also carried over to the next generation. Overall, their findings suggest that microplastic particles affected the oysters' ability to acquire and allocate energetic resources.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1519019113 (2016).

  5. Memory Consolidation

    Storing emotional memories

    1. Peter Stern

    When we remember events, we often also remember what we were feeling at the time. Cambiaghi et al. asked where in the brain we store such connections. To answer this, they conditioned rats to associate a tone with an unpleasant experience. They then simultaneously recorded from two brain regions, the higher-order auditory cortex and the amygdala, 1 day and 1 month after the conditioning. Animals displayed fearful behavior at both time points, and both areas showed learning-evoked changes. However, the two brain regions only interacted significantly after 1 month had passed. The degree of interaction predicted the animals' ability to recognize the tone as unpleasant.

    J. Neurosci. 36, 1647 (2016).

  6. Materials Science

    Two ways to surface recovery

    1. Marc S. Lavine

    Superhydrophobic surfaces often rely on specific surface chemistry or texturing to provide their extreme water repellency. Surface damage results in a loss of this property, although progress has been made in making self-healing materials that can restore either the surface architecture or chemistry. Lv et al. developed an epoxy shape-memory polymer with a lotus leaf-like surface texture that gives it superhydrophobicity. When damaged with an O2 plasma or physically crushed, the surface properties can be restored simply by heating the material to 85°C, with full restoration occurring even after several cycles of damage and recovery.

    Small 10.1002/smll.201503402 (2016).

  7. Influenza

    Influenza HA needs stability to spread

    1. Valda Vinson

    Influenza pandemics occur every few decades, but scientists still do not understand why only some strains cause pandemics. To enter host cells, the virus' hemagglutinin (HA) protein must undergo a pH-driven conformational change. During the 2009 pandemic, a swine H1N1 virus jumped to humans. Russier et al. now report that for swine H1N1, the HA conformational switch occurs at pH 5.5 to 6.0. In viruses isolated from humans, the pH of the switch changed from 5.5 to 5.6 early in the pandemic to 5.0 to 5.4 later in the pandemic. A swine H1N1 with HA mutated to switch at pH 6 was less pathogenic in mice and ferrets. The lower-pH switching probably increases HA stability in the upper respiratory tract.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1524384113 (2016).

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