Editors' Choice

Science  01 May 2015:
Vol. 348, Issue 6234, pp. 537
  1. Cell Behavior

    Sense-ible hair

    1. Lisa D. Chong

    Groups of hair cells influence each other's growth through quorum sensing

    PHOTO: © GLOBALP/ISTOCKPHOTO

    Could restoring hair growth depend on group behavior? Chen et al. report that damaged and healthy hair follicles grow cooperatively. The authors found that plucking 200 hairs in a specific pattern and density on the back of a mouse elicited not only the regrowth of the injured follicles but also the growth of up to five times that number of nearby uninjured follicles. Injured follicles release CCL2, a factor that recruits macrophages to the damaged area, and these secrete tumor necrosis factor–α, which stimulates stem cells in both plucked and unplucked follicles. The process reflects quorum sensing, where a population of cells communicates and coordinates behavior of the group through a signaling mechanism.

    Cell 161, 277 (2015).

  2. Noncoding RNAs

    Signaling stress

    1. L. Bryan Ray

    Small nucleolar RNAs (snoRNAs)—small noncoding RNAs better known for their roles as sequence guides for modification of other RNAs—may function to promote elimination of damaged cells undergoing metabolic stress. Youssef et al. explored RNA binding partners of the protein kinase PKR (protein kinase RNA–activated) and found them to be enriched in snoRNAs. Such binding activated PKR and was increased in cells treated with palmitic acid to mimic the metabolic stress seen in obese animals. Thus, snoRNAs appear to link metabolic stress to the activation of PKR, which in turn inhibits protein synthesis and promotes the death of stressed cells.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1424044112 (2015).

  3. T Cells

    T cells require mRNA modifications

    1. Laura M. Zahn

    T cells are important components of our immune system that recognize and respond to immune threats. Stimulation of T cells results in up-regulation of the RNA binding protein CELF2 (CUGBP, Elav-like family member 2). This gene is associated with posttranscriptional modifications of RNAs, including alternative splicing. Mallory et al. show that in response to T cell stimulation, expression of CELF2 is up-regulated and its transcripts are stabilized, ensuring an increase in the availability of this RNA. Furthermore, this up-regulation of CELF2 is associated with specific alternative exon transcripts and isoform expression within stimulated T cells. These results suggest that regulation of specific transcriptomes is important for mounting an immune response.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1423695112 (2015).

  4. Materials Science

    Seeing sonic hot spots

    1. Phil Szuromi

    PTFE coatiing on an NaCl crystal degraded by ultrasonic heating

    PHOTO: S. YOU ET AL, NATURE COMMUNICATIONS 6 (2 APRIL 2015) © NATURE PUBLISHING GROUP

    Mechanical impact can detonate explosives, but how impact heats these materials to initiate reactions has been unclear. You et al. used mild ultrasound irradiation to study composite materials—small crystals of sucrose or table salt in rubber—while performing thermal imaging. Uncoated particles remained unheated, but particles that had a coating that could delaminate (a polyethylene glycol layer that liquefies or Teflon) heated very rapidly (up to ∼22,000 K per second). Delamination allows the particle to move and friction-heat against the matrix, an effect that authors also saw in samples of polymer-bonded explosive (PBX).

    Nat. Commun. 10.1038/ncomms7581 (2015).

  5. Mineral Physics

    Strength to put a stop to sinking slabs

    1. Brent Grocholski

    Tectonic plates plunging toward Earth's core can unexpectedly stop sinking in the middle of the mantle. Marquardt and Miyagi provide a potential explanation involving the abundant mantle mineral ferropericlase. Their x-ray diffraction experiments revealed a large increase in the strength of ferropericlase with increased pressure. This translates to a viscosity increase at mid-mantle depths, providing a rheological barrier that subducted ocean lithosphere cannot easily penetrate. This mechanism of slab stagnation may also explain some of the mantle's well-known chemical heterogeneity.

    Nat. Geosci. 10.1038/ngeo2393 (2015).

  6. Antibiotics

    Extent of children's antibiotic exposure

    1. Julia Fahrenkamp-Uppenbrink

    Antibiotics are widely used in human and veterinary medicine and in personal care products, so people are increasingly exposed to them in the environment and in food. How high is the resulting antibiotic burden? Wang et al. measured the concentrations of 18 representative antibiotics in the urine of 1064 schoolchildren from three economically and geographically distinct areas in eastern China. They show that 58.3% of samples contained at least one antibiotic and that more than 20% of samples contained more than one. A lack of suitable analytical methods for some commonly used antibiotics means that the total antibiotic burden is likely to be even higher. Based on contamination data for the aquatic environment, exposures of children in the United States and Europe may be similar to those in this study.

    Environ. Sci. Technol. 10.1021/es5059428 (2015).

  7. Neuroscience

    Managing eight arms

    1. Peter Stern

    A central control center allows octopuses to move their heads and eight arms independently

    PHOTO: © AURIGADESIGN/ISTOCKPHOTO

    How does the octopus control its long and flexible arms? Levy et al. used kinematic analysis, filming animals as they maneuvered, and found that octopuses evolved a unique way of efficiently generating and controlling crawling. They can crawl in any direction relative to their body orientation, a feature found only in animals with radial organization, such as starfish. However, in contrast to those animals, octopuses control the direction in which the body faces, independently of the crawling direction. Octopuses can thus change the crawling direction while maintaining a fixed gaze direction, or rotate their body while continuing to crawl in the same direction. This indicates the existence of a sophisticated central command generator in the motor centers of the octopus brain.

    Curr. Biol. 25, 10.1016/j.cub.2015.02.064 (2015).