This Week in Science

Science  15 May 2015:
Vol. 348, Issue 6236, pp. 768
  1. Volcanology

    Yellowstone's missing magmatic link

    1. Brent Grocholski
    Yellowstone “supervolcano” CREDIT: NOAA

    Yellowstone is an extensively studied “supervolcano” that has a large supply of heat coming from a pool of magma near the surface and the mantle below. A link between these two features has long been suspected. Huang et al. imaged the lower crust using seismic tomography (see the Perspective by Shapiro and Koulakov). Their findings provide an estimate of the total amount of molten rock beneath Yellowstone and help to explain the large amount of volcanic gases escaping from the region.

    Science, this issue p. 773; see also p. 758

  2. Human Behavior

    Friends and family?

    1. Gilbert Chin

    Evolutionary theory stresses the importance of living with kin, not least because they share some of our genes. Nevertheless, a large-scale assessment of contemporary hunter-gatherer societies has established a consistent pattern of unrelated individuals living together. Dyble et al. used a modeling approach to suggest that a possible answer to this conundrum is that cohabitation choices are being governed equally by men and women.

    Science, this issue p. 796

  3. 3D Printing

    Mimicking complex shapes of natural shells

    1. Zakya H. Kafafi

    What design principles in seashells make their mechanical properties so outstanding? Tiwary et al. 3D-printed such shapes, based on their understanding of the stress distribution schemes found in seashells. The adoption of Mother Nature's design could have a strong impact on future engineering applications. For instance, the natural shape of a limpet shell reduces stress in the central cavity region, which protects its resident from external loads.

    Sci. Adv. 10.1126.sciadv.1400052 (2015).

  4. Quantum Optics

    Tailoring the quantum dynamics of light

    1. Jelena Stajic

    The energy levels of a quantum system are determined by the laws of quantum mechanics and the specifics of the physical setting. Light confined to a cavity has energy levels neatly arranged in a “ladder” of equidistant rungs, each rung corresponding to a fixed number of photons. Bretheau et al. devised a way to limit the dynamics to only the lowest few rungs by coupling the system to a qubit, which shifted the energy of one of the higher rungs. When they then drove the system at a frequency corresponding to the distance between the rungs, only the states lower in energy than the shifted state could participate.

    Science, this issue p. 776

  5. Mitosis

    Chromosomes: Let me be your guide

    1. Stella M. Hurtley

    Human corneal epithelial cell (center) undergoing chromosome congression

    CREDIT: © EYE35.PIX/ALAMY; MARIN BARISIC AND HELDER MAIATO

    The correct alignment of chromosomes at the center of the mitotic spindle—the metaphase plate—before cell division is one of the key mechanisms for the maintenance of genomic stability. But is there anything special about the microtubules of the spindle that helps this process? Barisic et al. demonstrate that chromosome alignment at the cell equator is controlled by a specific posttranslational modification of selected microtubules oriented toward the center of the mitotic spindle.

    Science, this issue p. 799

  6. Galaxy Evolution

    In a cluster of protogalaxies far, far away

    1. Ian S. Osborne

    Astronomers constantly scour the sky for astronomical objects that can provide insight and constrain their models and simulations of galaxy evolution. Hennawi et al. surveyed the ancient sky at an epoch when the universe was half its age for nebulae: large clouds of ionized hydrogen. They stumbled across a system containing four active galactic nuclei, or quasars; objects that are thought to be the progenitors of galaxies. Finding a nebula with a rare quadruple quasar system embedded within it allows detailed spectroscopic and motional studies that may help to refine current models of galaxy and galaxy cluster formation.

    Science, this issue p. 779

  7. Archaeology

    Cultural prehistory in southern Europe

    1. Andrew M. Sugden

    The Protoaurignacian culture appeared in the southern European archeological record around 42,000 years ago and was characterized by artefacts including personal ornaments and bladelets. Archaeologists have debated whether it was ancestral Homo sapiens or Neandertals who made these tools and ornaments. Benazzi et al. analyzed dental remains from two Protoaurignacian sites in Italy and confirm that they were H. sapiens. The arrival of this culture may have led to the demise of Neandertals in these areas (see the Perspective by Conard et al.).

    Science, this issue p. 793; see also p. 754

  8. Cancer Immunotherapy

    Giving antitumor T cells a boost

    1. Kristen L. Mueller

    Mutations allow tumors to divide, escape death, and resist treatment. But mutations can also cause tumors to express mutant proteins, which could potentially be exploited to drive antitumor T cell responses. Carreno et al. report the results of a small phase I trial seeking to do just this (see the Perspective by Delamarre et al.). They vaccinated three patients with advanced melanoma with personalized dendritic cell–based vaccines designed to activate T cells specific for mutations in the patients' cancer. T cells specific for mutant peptides did indeed expand. A next step will be to determine whether this promising strategy improves patient outcomes.

    Science, this issue p. 803; see also p. 760

  9. Neurodegeneration

    Making aggregation less aggravating

    1. Leslie K. Ferrarelli

    The accumulation of α-synuclein aggregates occurs in certain neurodegenerative disorders, including Parkinson's disease. Daniele et al. found that α-synuclein aggregates activated the receptor complex TLR1/2 on primary mouse microglia, leading to the production of proinflammatory cytokines. TLR1/2 antagonists, including a drug approved for treating hypertension, prevented the activation of microglia and cytokine secretion in response to aggregated α-synuclein. Thus, repurposing of drugs that also inhibit TLR1/2 may be beneficial for patients with synucleinopathies.

    Sci. Signal. 8, ra45 (2015).

  10. Cell Biology

    How cells know when they are the right size

    1. L. Bryan Ray

    Biologists have long recognized that cells exist in a large range of sizes. Cell size is also flexible: Cells can differentiate into another cell type with a very different size. External factors can also influence cell size, but the consistent size of a given cell type shows that cells have mechanisms to measure their own size and adjust their growth rate or rate of cell division to maintain uniformity. Ginzberg et al. review recent advances in understanding how cells know when they are at the right size.

    Science, this issue 10.1126/science.1245075

  11. Phosphorus Cycling

    The phosphorus redox cycle

    1. Nicholas S. Wigginton

    Phosphorus in the oceans cycles between +5 and +3 oxidation states. Most of the oceans' phosphorus is present as oxidized bioavailable phosphate (+5) compounds. Reduced organophosphorus compounds are also present but at much lower concentrations. Through field measurements in the western tropical North Atlantic Ocean and a series of laboratory incubations, Van Mooy et al. measured fast reduction rates of a small but appreciable amount of phosphates by plankton communities, forming phosphites and phosphonates (see the Perspective by Benitez-Nelson). On a global scale, this phosphorus redox cycle adds as much reduced phosphorus to the oceans as all pre-anthropogenic land runoff.

    Science, this issue p. 783; see also p. 759

  12. Neurodevelopment

    How to maintain a zebrafish brain

    1. Pamela J. Hines

    Even in the zebrafish brain, which seems better able than the human brain to generate new neurons, regenerative capacity may not be unlimited. Barbosa et al. mapped the fates of individual neuronal cells in live zebrafish over time. Seen as glowing dots, neural stem cells sustain the population of neurons, although not quite at full replacement rates. After injury to the brain, more of the stem cells were pulled into neuronal pathways, with fewer remaining to feed future replacement.

    Science, this issue p. 789

  13. Noncoding RNA

    Spreading small RNAs to protect the genome

    1. Guy Riddihough

    In animals, PIWI-interacting RNAs (piRNAs) are small noncoding RNAs that protect our germ lines from the ravages of transposons. To do this, piRNAs target and cleave transposon RNAs. Synthesis of piRNA is initiated by a cut made in a long, single-stranded precursor RNA. The piRNAs can also undergo a self-perpetuating amplification cycle (see the Perspective by Siomi and Siomi). Han et al. and Mohn et al. now reveal that piRNA biogenesis can also spread in a strictly phased manner from the site of initial piRNA formation. Spreading piRNA synthesis greatly increases their sequence diversity, potentially helping them to target endogenous and novel transposons more effectively.

    Science, this issue p. 817, p. 812; see also p. 756

  14. Animal Physiology

    A cold-water fish with a warm heart

    1. Sacha Vignieri

    Mammals and birds warm their entire bodies above the ambient temperature. Generally, this ability is lacking in other vertebrates, although some highly active fish can temporarily warm their swim muscles. Wegner et al. show that the opah, a large deepwater fish, can generate heat with its swim muscles and use this heat to warm both its heart and brain. This ability increases its metabolic function in cold deep waters, which will help the fish compete with other, colder-blooded species.

    Science, this issue p. 786

  15. Centrosomes

    A little bit of this and a little bit of that

    1. Stella M. Hurtley

    Centrosomes are the major microtubule-organizing centers in animal cells. Key to this function is the somewhat mysterious pericentriolar material (PCM). Woodruff et al. describe the in vitro reconstitution of PCM assembly. In cells, PCM is recruited by centrioles to form centrosomes that nucleate and anchor microtubules. SPD-5, the main component of the PCM matrix in Caenorhabiditis elegans, polymerized in vitro to form micrometer-sized porous networks. SPD-5 polymerization was directly controlled by the polo family kinase Plk1 and Cep192/SPD-2, two conserved regulators that control PCM assembly across metazoans.

    Science, this issue p. 808

  16. Multiple Sclerosis

    Rethinking the role of reactive T cells

    1. Angela Colmone

    In patients with multiple sclerosis (MS), damage to the nerve-insulating myelin sheath blocks the ability of neurons to conduct messages. Although the injury is thought to be caused by the body's own immune system, myelin-restricted immune cells exist in comparable numbers in MS patients and healthy controls. Now, Cao et al. report functional differences between myelin-reactive T cells from MS patients—which are proinflammatory— and those in healthy controls—which secrete more of the immunoregulatory cytokine interleukin-10. Thus, functional divergence in selected immune cells may contribute to disease development

    Sci. Transl. Med. 7, 287ra74 (2015).

  17. Development Economics

    Attacking the problem of extreme poverty

    1. Gilbert Chin

    A persistent concern about wellintentioned efforts to improve living standards for the 1.2 billion people who survive (if it can be called that) on less than $1.25 US per day is figuring out what works. A second concern is figuring out whether what works in one setting can be made to work in another. Banerjee et al. describe encouraging results from a set of pilot projects in Ethiopia, Ghana, Honduras, India, Pakistan, and Peru encompassing 11,000 households. Each project provided short-term aid and longer-term support to help participants graduate to a sustainable level of existence.

    Science, this issue 10.1126/science.1260799