Editors' Choice

Science  15 Aug 2014:
Vol. 345, Issue 6198, pp. 783
  1. Unfolded Proteins

    Stitching mRNA back together again

    1. Guy Riddihough

    RtcB (red) co-localizes with the endoplasmic reticulum (green)


    Cells get rid of toxic, inappropriately folded proteins in a process called the unfolded protein response (UPR). The UPR occurs in the cell's endoplasmic reticulum, which folds and sorts proteins. It requires an unconventional type of RNA splicing: the removal of small pieces of genetic material called introns from messenger RNA (mRNA). But biologists weren't sure how the spliced mRNA got put back together. Lu et al. now report that the enzyme RtcB patches together the two halves of a spliced mRNA that codes for XBP1, an important regulator of the UPR. In the endoplasmic reticulum, RtcB bound another enzyme, IREα, which splices the intron out of the XBP1 mRNA.

    Mol. Cell 55, 10.1016/j.molcel.2014.06.032 (2014).

  2. Aging

    A sweet decline for the aging fly brain

    1. L. Bryan Ray

    Our livers and muscles store glucose as glycogen, a branched polysaccharide. Glycogen is a major energy reserve, but it may play a more sinister role in the aging brain. Along with other components, glycogen forms aggregates in the brains of aging mice, humans, and flies that correlate with a decline in neuron function. To better understand this, Sinadinos et al. experimented with fruit flies. They used RNA interference to inhibit the flies' production of glycogen synthase, the enzyme that makes glycogen from glucose. Then the researchers measured how fast the flies could climb. As the flies aged, their neurons functioned better than those of controls. Treated male flies—but not females—lived longer.

    Aging Cell 10.1111/acel.12254 (2014).

  3. Coastal Ecosystems

    The cost of economic growth

    1. Andrew M. Sugden
    Dalian, Liaoning Province, ChinaCREDIT: © HENRY WESTHEIM PHOTOGRAPH /ALAMY

    Anthropomorphic changes threaten the stability of coastal ecosystems, but whether economic growth contributes to such degradation is unknown. To find out, He et al. assessed the trends in coastal population, economy, and 15 different human impacts, including salt production, fishing, and marine freight transport, on 30,000 km of Chinese coastline both before and after economic reforms began in China in 1978. They found that all 15 human impacts increased after 1978, even though population growth remained constant, suggesting that economic growth contributed to coastal ecosystem decline. The authors highlight the need for a national policy of environmental management to protect the coupled human-ocean ecosystem.

    Sci. Rep. 4, 5995 (2014).

  4. Optical Communication

    Steering an optical signal without wires

    1. Ian S. Osborne

    All wireless communications—radio, cell phones, wi-fi, or anything else—need reliable links between transmitters and receivers. In general, higher-frequency bands can convey more information than lower-frequency ones. Using a patterned array of tiny metallic nanoantennas, Dregely et al. show that they can steer an optical beam wirelessly from a transmitter to any one of a number of receivers. Because light has such high frequencies, these kinds of directed wireless optical channels should be able to transmit even greater amounts of information than devices using more traditional, longer-wavelength approaches.

    Nat. Commun. 10.1038/ncomms5354 (2014).

  5. Chemistry

    Coatings keep gunk off nanoparticles

    1. Marc S. Lavine
    A corona-free nanoparticleCREDIT: D. F. MOYANO ET AL. ACS NANO 8, 7 ((27 JUNE 2014) © 2014 AMERICAN CHEMICAL SOCIETY

    Nanoparticles have many potential therapeutic applications, such as delivering drugs. In untreated biological fluids such as plasma or serum, however, protein layers can cover the particles' surfaces, interfering with their intended function. Moyano et al. show that gold nanoparticles coated with zwitterionic ligands — neutral molecules with both positively and negatively charged regions — prevent protein coronas from forming around the particles. As a consequence, the nanoparticles can interact with cells as intended. Furthermore, the hydrophobicity of the nanoparticles can be tuned, which affects the cellular uptake of the particles.

    ACS Nano 10.1021/nn5006478 (2014).

  6. Viral Competition

    How infection rate determines virus spread

    1. Pamela J. Hines

    When a virus attacks a plant, it can damage cells locally or it can spread to the entire plant through the vasculature. Viral spread increases the odds that the virus could jump to other plants. To better understand this process, Rodrigo et al. mathematically modeled the timing and features that contribute to viral spead. They also watched viruses infect plants in experiments. A virus was sure to spread systemically when it infected many sites on the plant, and the most successful viruses were the ones that replicated the fastest, not the ones that spread quickly from cell to cell. But with a more moderate number of infection sites, rapid jumping between cells determined success.

    J. R. Soc. Interface 11, 20140555 (2014).

  7. Hydrology

    Looking beneath the drying surface

    1. H. Jesse Smith

    Groundwater is being depleted in the Colorado Basin region even faster than the rapid drawdown of Lakes Powell and Mead. Castle et al. determined groundwater depletion in the American Southwest by using data from the GRACE satellites, which measure minute variations in Earth's gravity field: in this case, ones associated with water movement below the surface. Looking at 9 years of results beginning at the end of 2004, 4 years after the current drought there began, they find that groundwater use makes up a much larger fraction of basin water use than previously recognized. Its continued depletion, they conclude, may pose a serious threat to the region's ability to meet future water needs.

    Geophys. Res. Lett. 10.1002/2014GL061055 (2014).

  8. Ocean Chemistry

    Mercury levels in surface ocean tripled

    1. Jai You

    Human activities such as coal burning have tripled mercury in the surface ocean, posing a threat to human health, a study finds. Mercury emitted to the atmosphere rains out to the oceans, where it is converted to the neurotoxin methylmercury that bioaccumulates in fish. Lamborg et al. collected 8 years of water samples from four oceans and used databases of human-generated CO2 from coal burning to scale up to worldwide pollution. The ocean contains 60,000 to 80,000 tons of pollution mercury, they found, two-thirds in water shallower than 1000 meters. In the top 100 meters, mercury has tripled compared to preindustrial times.

    Nature, 10.1038/nature13563(2014).

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