This Week in Science

Science  03 Oct 2014:
Vol. 346, Issue 6205, pp. 50
  1. Marine Geophysics

    High-resolution tectonic solutions

    1. Brent Grocholski
    CREDIT: SANDWELL ET AL.

    Detailed topographic maps are available for only a small fraction of the ocean floor, severely limited by the number of ship crossings. Global maps constructed using satellite-derived gravity data, in contrast, are limited in the size of features they can resolve. Sandwell et al. present a new marine gravity model that greatly improves this resolution (see the Perspective by Hwang and Chang). They identify several previously unknown tectonic features, including extinct spreading ridges in the Gulf of Mexico and numerous uncharted seamounts.

    Science, this issue p. 65; see also p. 32

  2. Mammalian Energetics

    The costs and benefits of stalking and chasing

    1. Sacha Vignieri

    Organisms live under a constant balance between getting and using energy. Large carnivores may feel this balance more acutely because of the large amounts of energy needed to capture and subdue their prey. Williams et al. and Scantlebury et al. used remote measures of physiology and behavior to identify the hunting strategies of the stalking North American puma and the speedy African cheetah (see the Perspective by Laundré). In both cases the cats' hunting strategies are well matched to produce a balance between the energy they spend on the hunt and the energy they acquire from their prey, despite their very different strategies and levels of competition.

    Science, this issue p. 81, p. 79; see also p. 33

  3. Aging

    Excess signaling is bad for the aging brain

    1. L. Bryan Ray
    Mouse choroid plexus (green) nuclei (blue) CREDIT: BARUCH ET AL.

    Preventing antiviral-like responses may protect function in the aging brain. Baruch et al. monitored messenger RNA production in the choroid plexus, the interface between the blood and cerebrospinal fluid, in young and old mice (see the Perspective by Ransohoff). They detected an inflammatory response in older mice not present in the brain of young mice that was also seen in old aged human samples postmortem. Preventing signaling by the cytokine interferon-I, which normally helps in the antiviral response of the immune system, helped prevent the decrease in cognitive function seen in aged mice.

    Science, this issue p. 89; see also p. 36

  4. T Cell Memory

    Resident memory T cells sound the alarm

    1. Kristen L. Mueller

    Immunological memory protects against reinfection. Resident memory T cells (TRM) are long-lived and remain in the tissues where they first encountered a pathogen (see the Perspective by Carbone and Gebhardt). Schenkel et al. and Ariotti et al. found that CD8+ TRM cells act like first responders in the female reproductive tissue or the skin of mice upon antigen reencounter. By secreting inflammatory proteins, TRM cells rapidly activated local immune cells to respond, so much so that they protected against infection with an unrelated pathogen. Iijima and Iwasaki found that CD4+ TRM cells protected mice against reinfection with intravaginal herpes simplex virus 2.

    Science, this issue p. 98, p. 101, p. 93; see also p. 40

  5. Biofuels

    Tricks for boosting yeast's ethanol yields

    1. Nicholas S. Wigginton

    To become a widely used source of fuel, widespread industrial production of ethanol using yeast needs to be simple and efficient. However, two conditions ideal for boosting production—tolerance of higher temperatures and high concentrations of ethanol—have been limiting (see the Perspective by Cheng and Kao). Now, Caspeta et al. have used adaptive laboratory evolution to find yeast strains that can tolerate high temperatures and Lam et al. have identified a route to improve yeast's resistance to high concentrations of ethanol.

    Science, this issue p. 75, p. 71; see also p. 35

  6. HIV Epidemiology

    The hidden history of the HIV pandemic

    1. Caroline Ash

    Rail and river transport in 1960s Congo, combined with the sexual revolution and changes in health care practices, primed the HIV pandemic. Faria et al. unpick the circumstances surrounding the ascendancy of HIV from its origins before 1920 in chimpanzee hunters in the Cameroon to amplification in Kinshasa. Around 1960, rail links promoted the spread of the virus to mining areas in southeastern Congo and beyond. Ultimately, HIV crossed the Atlantic in Haitian teachers returning home. From those early events, a pandemic was born.

    Science, this issue p. 56

  7. Photochemistry

    Illuminating oxygen out of carbon dioxide

    1. Jake Yeston

    It has long been known that high-energy ultraviolet light can split carbon dioxide into CO and O fragments. Lu et al. have now uncovered a parallel pathway that appears to yield C and O2 instead (see the Perspective by Suits and Parker). By precisely measuring the energy and trajectory of the carbon fragment after CO2 irradiation, O2 formation could be inferred. The results introduce a potential mechanism for abiotic oxygen production in CO2-heavy atmospheres of other planets.

    Science, this issue p. 61; see also p.30

  8. Asthma

    How the common cold can worsen asthma

    1. ACC

    Rhinoviruses—the main causes of the common cold—can make asthma attacks worse. Now Beale et al. report that one reason may be because rhinoviruses cause lung epithelial cells to make the cytokine interleukin-25 (IL-25). More IL-25 is produced in people with asthma than in those that are healthy. In mice with allergic “asthma,” rhinovirus infection triggered IL-25 production, and blocking the IL-25 receptor eased the increased asthma symptoms. Thus, as the cold season approaches, blocking IL-25 may be a promising therapeutic strategy in asthmatics.

    Sci. Transl. Med. 6, 256ra134 (2014).

  9. Cancer

    A new approach for treating colon cancer?

    1. Jason D. Berndt

    Most patients with colon cancer have a mutation that results in the Wnt/β-catenin pathway being “on” all the time. But inhibitors of this pathway interfere with the continuous renewal of the epithelial cells lining the intestinal tract. Phesse et al. discovered that the signaling pathway involving the receptor gp130, its associated Jak kinases, and the transcription factor Stat3 enhanced the growth of intestinal tumors in mice. Inhibiting this pathway stopped cell proliferation and reduced tumor growth. Drugs targeting the Jak-Stat3 pathway are currently in clinical trials for treating hematological malignancies, so hopefully may also be useful for treating colon cancer.

    Sci. Signal. 7, ra92 (2014).

  10. Bionanotechnology

    Biological sensing using nanoparticles

    1. Marc S. Lavine

    Colloidal fluorescent and plasmonic nanoparticles yield intense responses to incident light, making them useful as sensors or probes for sensitive detection in solution. Howes et al. review the potential uses of nanoparticle biosensors in research and diagnostics. A range of methods allow for the chemical modification of the particle surfaces so that they can be tuned for specific analytes and give optical signals for a range of biological conditions of interest. Signals can be detected in complex media or in vivo making the particles of interest for both laboratory research and in clinical settings.

    Science, this issue 10.1126/science.1247390

  11. Stem Cell Signaling

    Controlling stem cells and their niches

    1. Beverly A. Purnell

    Adult organs such as the intestines and skin continually renew themselves every few days or weeks. In several mammalian tissues, this renewal relies on Wnt signaling. Clevers et al. review this crucial role in stem cell self renewal. Wnt plays a pivotal role in tissue regeneration even in the earliest animals. Wnt proteins function mainly as short-range signals between adjacent cells. The short-range, spatially-constrained nature of Wnt signals underpins mammalian stem cell niche architecture and tissue self-organization.

    Science, this issue 10.1126/science.1248012

  12. Nanophotonics

    Controlling the flow of light with nanoparticles

    1. Ian S. Osborne

    Light propagating through optic fibers could provide the ultimate in information flow, but controlling the direction of flow is a key requirement. Petersen et al. show that the directional flow of light in a fiber can be controlled by placing a single gold nanoparticle on or near the surface of the fiber. By exploiting the chiral properties of light (the spin-orbit interaction), the authors demonstrate that the “handedness” or polarization state of the light hitting the particle determines in which direction the light flows in the fiber.

    Science, this issue p. 67

  13. Proteomics

    Mapping human drug targets in the cell

    1. Valda Vinson

    To understand both the beneficial and the side effects of a drug, one would need to know its full binding profile to all cellular proteins. Savitski et al. take significant steps toward meeting this daunting challenge. They monitored the unfolding or “melting” of over 7000 human proteins and measured how small-molecule binding changes individual melting profiles. As a proof of principle, over 50 targets were identified for an inhibitor known to bind a broad spectrum of kinases. Two cancer drugs, vemurafib and Alectinib, are known to have a side effect of photosensitivity. The thermal profiling approach identified drug-protein interactions responsible for these side effects.

    Science, this issue 10.1126/science.1255784

  14. Prostate Cancer

    Mutant protein in tumors hits the DEK

    1. Paula A. Kiberstis

    Cancer genome sequencing projects have uncovered a multitude of mutations in human tumors. Understanding whether and how these mutations contribute to tumor development and progression could ultimately lead to new therapies. Theurillat et al. studied the protein product of a gene that is recurrently mutated in prostate cancer. Normally this protein helps attach a biochemical tag to cellular proteins that marks them for degradation. The new work shows that the tumor-associated mutant protein loses this tagging ability, which results in the stabilization of a handful of cellular proteins that would otherwise be degraded. One of the most intriguing of these proteins was DEK, which helps prostate cancer cells invade into surrounding tissue.

    Science, this issue p. 85

  15. Conservation

    Oil palm may become a threat to tropical forests

    1. Julia Fahrenkamp-Uppenbrink

    Palm oil is used in consumer products from margarine and ice cream to shampoo and detergents. Vast forests in East Asia have been cleared to create oil palm plantations. Higher-yielding oil palm varieties would allow more oil to be produced on the same amount of land. Could such varieties help to save further forests from destruction? In their Perspective, Carrasco et al. argue that the more likely outcome is further deforestation in the tropics as oil production shifts from temperate to tropical areas. This shift may result in land being spared in temperate areas. However, tropical forests are likely to come under further threat, particularly in Africa and South America.

    Science, this issue p. 38