Editors' Choice

Science  19 May 2017:
Vol. 356, Issue 6339, pp. 713
  1. Nanotechnology

    Just one drop will do it

    1. Marc S. Lavine

    Mr. Spock uses a handheld sensor with Scotty.

    PHOTO: UNITED ARCHIVES/IFTN CINEMA COLLECTION/ALAMY

    Handheld sensors, often found in science fiction stories as a way of collecting a broad spectrum of data with a single device, are becoming real devices through the continuous miniaturization of technology. Engel et al. combine an electronic array of sensors with optical microspectroscopy and atomic force microscopy, based on two-dimensional materials, on a single platform. Liquids can be distinguished both electronically and optically, and dynamic surface wetting can also be monitored. At the limits of the device, the topography and optical spectra of isolated oil emulsion droplets with volumes less than 10 attoliters could be determined.

    Nano Lett. 10.1021/acs.nanolett.6b03561 (2017).

  2. Development

    Mom tells virus what to do

    1. Beverly A. Purnell

    Mother's directions must be followed, even in the earliest stage of embryo development. The maternal genome is read up until a phase called the maternal-to-zygotic transition. At this point, which corresponds to the two-cell stage in mice, the embryonic genome takes over. Using single-cell analyses, Huang et al. examined the function of the maternal factor Stella. Widespread transcription changes result when Stella is eliminated. In particular, endogenous retroviruses such as MuERV-L that are normally active in the early embryo display impaired expression when Stella is knocked down in vivo. Hence, the normal activity of ancient viruses must be properly turned on for transitioning from maternal to zygotic control in development.

    eLife 10.7554/eLife.22345 (2017).

  3. Ocean Ecology

    Expanding toxic algal blooms

    1. Catherine Griffin

    Higher sea surface temperatures are increasing algal blooms in northern oceans.

    PHOTO: ORSOLYA HAARBERG/NPL/MINDEN PICTURES

    Ocean temperatures in the North Atlantic and North Pacific oceans have increased in recent decades, particularly in coastal areas. This has been associated with increased algal blooms and, where these blooms include algal species that produce biotoxins, the potential for increases in cases of paralytic and diarrhetic shellfish poisoning. Gobler et al. used high-resolution records of sea surface temperature from 1982 to 2016 and temperature-dependent growth rates of two toxic algal species to create models of harmful algal blooms. These models were validated in areas of the North Atlantic by observations in other studies of increased bloom frequency and range that matched predicted locations. This information could potentially be used to predict the future spread of harmful algal blooms and the consequent impact on human health.

    Proc. Natl. Acad. Sci. U.S.A. 114, 4975 (2017).

  4. Metabolic Disease

    Genes and BMI conspire to make fatty liver

    1. Paula A. Kiberstis

    Nonalcoholic fatty liver disease (NAFLD) is estimated to affect 20% of the world's population. NAFLD begins with an abnormal buildup of fat in the liver that is “clinically silent.” In a subset of individuals, NAFLD progresses to liver inflammation, cirrhosis, and cancer. Identifying which individuals will progress is a major goal of current research. Stender et al. take a step toward this goal by studying gene-environment interactions. They find that high BMI (body mass index), a well-known risk factor for NAFLD, amplifies the effects of certain genetic risk factors. Obese individuals carrying a specific allele of the PNPLA3 gene, for example, have nearly a sixfold greater risk of developing cirrhosis than obese individuals carrying a different allele.

    Nat. Genet. 10.1038/ng.3855 (2017).

  5. Microbiota

    Mutualists endow certain appetites

    1. Caroline Ash

    Life span and reproductive success can depend on controlling dietary protein intake. Yet the importance of gut microbial symbionts in appetite control is not understood. Leitão-Gonçalves et al. used the fruitfly, Drosophila, to test what influence their microbiota might have on food choice. Fruitflies like sugar, but after they have mated, they prefer to eat yeast to gain essential amino acids for egg-making. By knocking out the phenylalanine hydroxylase gene, flies can be duped into sensing that tyrosine is an essential amino acid. If tyrosine is missing from a chemically defined diet, the engineered flies' fecundity falls and, if given the choice, they will voraciously eat yeast to compensate for the missing nutrient. If particular live microbiota species (Acetobacter pomorum and lactobacilli) are introduced into the food of the engineered flies, they lose their taste for yeast and resume egg-laying. Unexpectedly, the microbiota do not seem to directly provide a compensatory source of the missing amino acid. The precise mechanism for the protective effect of the microbiota remains elusive.

    PLOS Biol. 10.1371/journal.pbio.2000862 (2017).

  6. Education

    Research experience is not just for students

    1. Melissa McCartney

    The benefits of authentic research experiences for undergraduate students are well documented, but how do research advisors benefit from having undergraduate students in their lab? Hayward et al. interviewed 30 research advisors at various career stages about their motivation for supporting undergraduate research. Responses indicated that a blend of instrumental and intrinsic motivation influenced most advisors, whereas a small group of advisors, all in the early stages of their careers, reported only instrumental motivation. These differences in motivations likely affect the way that advisors work with students and may serve as the starting point for designing new methods for training, and retaining, high-quality research advisors.

    CBE Life Sci. Educ. 10.1187/cbe.16-07-0229 (2017).

  7. Quantum Optics

    A game of quantum catch

    1. Ian S. Osborne

    Realization of a quantum communication network or quantum internet will depend on the ability to successfully transfer quantum states between nodes of the network. Photons are expected to be the carriers of that information, but scattering losses and a mismatch between sender and receiver nodes can limit their utility. By tuning the energy levels of a receiver dot and introducing filters that suppress noise, Delteil et al. demonstrate the transfer of single photons from one quantum dot to another 5 m away. Their method allows the receiver dot to signal absorption of a single photon without compromising the actual quantum state, thereby presenting a possible route for developing a larger quantum network.

    Phys. Rev. Lett. 118, 177401 (2017).

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