This Week in Science

Science  18 Sep 2015:
Vol. 349, Issue 6254, pp. 1296
  1. Human Genetics

    Greenlanders' genomes signal a fatty diet

    1. Laura M. Zahn

    Inuit dogsled on the sea ice outside Tasiilaq in East Greenland

    PHOTO: MADS PHIL AND VISIT GREENLAND

    The evolutionary consequences of inhabiting a challenging environment can be seen within the genomes of Greenland Inuit. Fumagalli et al. have found signs of selection for genetic variants in fat metabolism, not just for promoting heat-producing brown fat cells but also for coping with the large amounts of polyunsaturated fatty acids found in their seafood diet (see the Perspective by Tishkoff). Genes under selection in these populations have a strong effect on height and weight of up to 2 cm and 4 kg, respectively, as well as a protective effect on cholesterol and triglyceride levels.

    Science, this issue p. 1343; see also p. 1282

  2. Vaccines

    Flu vaccine candidate STEMs the tide

    1. Kristen L. Mueller

    Every year we need a new flu vaccine, because influenza virus constantly mutates the major target of antibodies to flu: the “head” region of the viral hemagglutinin (HA) protein. Avoiding the problem of mutation requires a vaccine that elicits antibodies against the more conserved “stem” region of HA. During infection, antibodies are occasionally produced that recognize the stem and that neutralize a broad range of influenza virus strains. Impagliazzo et al. engineered an HA stem–only vaccine candidate that elicited broadly neutralizing antibodies in mice and nonhuman primates and that protected mice against multiple influenza strains.

    Science, this issue p. 1301

  3. Applied Optics

    Wrap-around invisibility cloak

    1. Ian S. Osborne

    An invisibility cloak can be used to conceal an object from view by guiding light around it. Most cloaks developed so far have bulky structures that are difficult to scale up for hiding large objects. To design a thin invisibility cloak that can be wrapped around an object such as a sheet or skin, Ni et al. designed a two-dimensional metamaterial surface. Such flexible, highly reflective materials could be manufactured at large scale to hide large objects.

    Science, this issue p. 1310

  4. Cancer and Development

    Smoothened signals through G proteins

    1. Wei Wong

    During development, the Hedgehog signaling pathway regulates gene expression through the Gli family of transcription factors. The gene encoding the Hedgehog effector Smoothened (Smo) is aberrantly expressed in some types of breast cancers, and thus various drugs have been developed to target this protein. Villanueva et al. showed that Smo promoted cell proliferation in the mammary glands of mice via the G protein Gαi2, rather than through Gli-mediated changes in gene expression (see also the Focus by Ogden). This discovery indicates that Smo-targeting drugs should also be screened for their ability to inhibit Gαi2 activation.

    Sci. Signal. 8, ra92 and fs16 (2015)

  5. Ferroelectrics

    Thinning films induces ferroelectricity

    1. Jelena Stajic

    Thin ferroelectric films are needed in computers and medical devices. However, traditional ferroelectric films typically become less and less polarized the thinner the films become. Instead of using a good ferroelectric and making it thinner, Lee et al. started with SrTiO3, which in its bulk form is not ferroelectric. This material does have naturally occurring nanosized polarized regions. and when the thickness of the SrTiO3 films reaches the typical size of these regions, the whole film aligns and becomes ferroelectric.

    Science, this issue p. 1314

  6. Organic Chemistry

    Lighting the way to aryl C-N bonding

    1. Jake Yeston

    Medicinal chemists like to add N bonds to the C atoms of aromatic rings to make bioactive compounds. By harnessing the energy in visible light, Romero et al. made these links and transformed C-H into C-N bonds. They used a blue-absorbing acridinium ion to activate a ring C for an incoming N partner. A nitroxyl radical co-catalyst (TEMPO) then choreographed the transfer of the H atom to O. The reaction worked for a broad range of substrates, including ammonium as a N source.

    Science, this issue p. 1326

  7. Neurodevelopment

    Youthful damage limitation in stem cells

    1. Pamela J. Hines

    Every day brings more risk of damage to stem cells, which could have consequences for the whole organism. Moore et al. observed that dividing neural stem cells in rodents establish a diffusion barrier that restricts damaged proteins to one daughter cell, leaving the other with intact molecules. But with age this diffusion barrier weakens, so that replicating stem cells of older animals are less able to exclude damaged proteins than are the stem cells of younger rodents.

    Science, this issue p. 1334

  8. Prostate Cancer

    Circulating signals of drug resistance

    1. Paula A. Kiberstis

    Cancer drugs often lose their effectiveness because tumors acquire genetic changes that confer drug resistance. Ideally, patients would be switched to a different drug before tumor growth resumes, but this requires early knowledge of how resistance arose. Miyamoto et al. have developed a non-invasive method to spot resistance by sequencing RNA transcripts in single circulating tumor cells (CTCs) (see the Perspective by Nanus and Giannakakou). For example, in prostate cancer patients, drug resistance was triggered by activation of the Wnt signaling pathway. But CTCs are rare and fragile, and the technology needs further development before it is used in clinical practice.

    Science, this issue p. 1351; see also p. 1283

  9. Virology

    A good model for the “good boy virus”

    1. Orla M. Smith

    Infection with human pegivirus (HPgV) provides a measure of protection to HIV-infected individuals by slowing HIV replication. This phenomenon has earned HPgV the nickname “good boy virus.” How HPgV achieves this protective effect remains a mystery in part because no animal model of HPgV infection exists. Bailey et al. discovered that viruses closely related to HPgV also occur in wild baboons and can infect laboratory macaques, thus providing an opportunity to discover what tissues HPgV infects and how it is transmitted and replicated.

    Sci. Transl. Med. 7, 305ra144 (2015).

  10. Economics

    Few thoughts for those with the most

    1. Gilbert Chin

    A weighty scholarly tome has sparked a year-long public discussion of the unevenness of income and wealth distributions in the United States. In essence, a few people have a lot of both. Moral philosophers and economists have argued for centuries about the tradeoffs in life strategy that might explain wealth imbalance: between fairness and selfishness, and equality and efficiency. Fisman et al. describe the preferences of a group of elite students at Yale Law School. These elites lean toward selfishness and efficiency more than the average American, and these preferences are reflected in their job choices.

    Science, this issue p. 10.1126/science.aab0096

  11. Metallic Glasses

    Percolating cluster, factal structure

    1. Brent Grocholski

    Metallic glasses are appealing materials because they are strong and can bend without breaking. These materials are disordered but possess none of the defects seen in crystalline counterparts. Chen et al. developed a model for metallic glasses in which clusters of atoms float free in the liquid, begin to jam, and finally organize into a short-range fractal structure below the glass transition temperature. This model also accounted for the density and high strength characteristics of bulk samples.

    Science, this issue p. 1306

  12. Quantum Optics

    Entangling atoms by persistent poking

    1. Jelena Stajic

    In quantum mechanics, repeated measurements targeting a particular unoccupied state of the system can keep that state from being occupied. Barontini et al. used this so-called quantum Zeno effect to restrict the dynamics of an ensemble of 36 87Rb atoms acting as qubits and residing in an optical cavity. The measurement of the cavity transmission blocked off the collective state in which all qubits were in their ground state. The ensuing dynamics resulted in the entanglement of the atoms, creating a potential resource for quantum information processing.

    Science, this issue p. 1317

  13. Ceramic Fuel Cells

    Cooler ceramic fuel cells

    1. Phil Szuromi

    Ceramic ion conductors can be used as electrolytes in fuel cells using natural gas. One drawback of such solid-oxide fuel cells that conduct oxygen ions is their high operating temperatures (at least 600°C). Duan et al. have made a proton-conducting ceramic fuel cell with a modified cathode material that exhibits high performance on methane fuel at 500°C (see the Perspective by Gorte).

    Science, this issue p. 1321; see also p. 1290

  14. Mineral Surfaces

    Driving dissolution with x-rays

    1. Nicholas S. Wigginton

    Carbonate minerals are important for Earth's carbon cycle. They precipitate directly from solution into diverse materials, depending on their physical or biological source. Whether carbonate minerals grow or dissolve is controlled by the thermodynamic drivers of the mineral/water interface. To control and observe the reactions, Lanaait et al. developed a synchrotron x-ray technique that images calcium carbonate surfaces in water and selectively tunes the solution saturation state (see the Perspective by Wolthers). The x-ray beam drives fast-moving reaction fronts far from equilibrium that are more limited by solution-ion transport than by surface processes.

    Science, this issue p. 1330; see also p. 1288

  15. Virology

    The devil in the dengue details

    1. Caroline Ash

    Along with their mosquito vectors, dengue viruses are spreading worldwide to infect millions of people. For a few, subsequent infection results in lethal hemorrhagic disease. Katzelnick et al. used antibody-binding data to map structural divergence and antigenic variation among dengue viruses. Comparing results in monkeys and humans, the viruses approximately clustered into the four known groups. However, the four virus groups showed as much antigenic distance within a group as between groups. This finding helps explain why immune responses to dengue are highly variable, and it has complex implications for epidemiology, disease, and vaccine deployment.

    Science, this issue p. 1338

  16. Structural Biology

    Caught in the act of copying

    1. Guy Riddihough

    The genomes of double-stranded RNA (dsRNA) viruses consist of about a dozen dsRNA segments enclosed by a protein coat. Inside the host cell, the coat remains intact, and the dsRNAs have to replicate within the coat. Liu and Cheng used cryo–electron microscopy of cypovirus particles to catch the dsRNAs in the act of being copied. The structures revealed that the RNA formed a liquid-crystalline array on which viral enzymes carry out multiple rounds of transcription to replicate the viral genome.

    Science, this issue p. 1347

  17. Small Peptides

    Small peptide regulates protein activity

    1. Beverly A. Purnell

    Coding and noncoding RNAs can produce peptides from small open reading frames (smORFs), with a variety of mostly unknown functions. Using a genome-wide screen, Zanet et al. show that Polished rice (Pri) smORF peptides control fruit fly development by binding to an E3 ubiquitin ligase. This changes the ligase's selectivity and triggers proteasome-dependent maturation of the developmental transcription factor Shavenbaby. Other smORF peptides may act by a similar mechanism to regulate protein activity.

    Science, this issue p. 1356

  18. Energy

    A call for fossil fuel price reform

    1. Julia Fahrenkamp-Uppenbrink

    Coal is responsible for more carbon dioxide emissions per ton burnt than any other fossil fuel. Yet coal plants are being built around the world, particularly in China and other rapidly developing countries. In his Perspective, Edenhofer explores the reasons for the renaissance of coal. Fossil fuel subsidies are a key factor driving increased coal use, because they not only factor in fiscal spending but also include social costs, such as those to public health. Unless prices are reformed quickly to remove such wide-ranging incentives, climate change mitigation is imperiled.

    Science, this issue p. 1286