Editors' Choice

Science  12 Feb 2016:
Vol. 351, Issue 6274, pp. 677
  1. Soil Biology

    Plant probiotics to the rescue

    1. Caroline Ash

    Soil-dwelling bacteria can protect strawberry plants from fungal wilt

    PHOTO: © OLEKSANDR SHEVCHENKO/ALAMY STOCK PHOTO

    Some soils protect crops against their microbial attackers without any pesticides or fungicides. Cha et al. investigated the microbial and biochemical basis of this effect in a patch of soil that excluded fungal wilt on strawberry plants, despite 15 years of monoculture. Mixing in the protective soil transferred this suppressive effect into neighboring disease-ridden soils, which gained increasingly better disease-control capacity with successive growing cycles. A strain of Streptomyces bacteria, a group renowned for producing antibiotics, emerged as the chief agent that suppressed the pathogenic fungi. The Streptomyces produced an interesting large heat-stable thiopeptide antibiotic with antifungal properties. Thus, much like the development of probiotics to combat gut diseases, probiotics for soil should be feasible.

    ISME J. 10, 119 (2016)

  2. Stem Cells

    Translating stem cell quiescence

    1. Beverly A. Purnell

    Many tissues harbor a reservoir of stem cells that remains quiescent but can be activated as needed for growth and repair. How cells enter, maintain, and then exit quiescence is incompletely defined. Studying skeletal muscle stem cells in mice, Zismanov et al. reveal a role for translational repression. Stem cell quiescence requires phosphorylation (a posttranslational protein modification) of the translation initiation factor eIF2α at a particular amino acid residue; dephosphorylation (removal of the phorphoryl group) or blocking phorphorylation causes muscle stem cells to exit quiescence and differentiate. Moreover, inhibiting dephosphorylation leads muscle stem cells to self-renew and regenerate. Manipulating eIF2α phosphorylation may represent a method to regulate the regenerative capacity of stem cells for clinical use.

    Cell Stem Cell 18, 79 (2016).

  3. Ecotoxicology

    PCBs are still a problem for some marine life

    1. Sacha Vignieri

    Some cetacean species in European waters still harbor high levels of PCBs

    PHOTO: © MARTIN STRMISKA/ALAMY STOCK PHOTO

    Due to their environmental toxicity, most developed countries banned polychlorinated biphenols (PCBs) in the 1970s and 1980s. Since then, studies in marine regions off North America have shown a continued downward trend in their occurrence and levels in marine mammals and seabirds, but Jepson et al. find that this is not the case for marine mammals in European waters. Specifically, they looked at PCB levels in four cetacean species (the harbour porpoise, striped dolphin, bottlenose dolphin, and Atlantic killer whale). PCB levels in three of the four species were at, or above, established toxicity levels. The toxic effects of such high levels may be contributing to the observed declines and recruitment failures currently observed in these species.

    Sci. Rep. 10.1038/srep18573 (2016).

  4. Kidney Disease

    Potassium loss stresses out kidney cells

    1. Paula A. Kiberstis

    African-Americans are five times more likely than Caucasians to develop advanced kidney disease. Two sequence variants in a gene called APOL1 confer most of this elevated risk. Scientists think that the prevalence of these sequence variants in people of African descent probably arose because they also confer protection against parasite infection. The APOL1 gene encodes the protein apolipoprotein L1, which forms ion pores in the kidney cell membrane, but how the risk variants cause kidney disease remains a mystery. Studying cultured kidney cells, Olabisi et al. find that the APOL1 risk variants cause excessive loss of potassium from the cells. This in turn activates stress-activated enzymes called kinases, which ultimately leads to kidney cell death.

    Proc. Natl. Acad. Sci. U.S.A. 113, 830 (2016).

  5. Education

    Critical thinking: Not just for majors

    1. Melissa McCartney

    Being able to draw conclusions based on evidence in order to make an informed decision is a key aspect of scientific literacy. Rowe et al. report on a general education science course designed specifically to teach critical thinking, essentially the nature of science, rather than just the facts of science. Through the incorporation of case studies, the course examined science as it relates to the students' daily lives (for example, the vaccine-autism controversy) by using scientific processes such as argumentation, evaluating data, drawing conclusions, and designing the next experiment. A pre/post-test survey showed that participating students significantly improved their critical thinking skills and were more willing to engage with science that the public finds controversial.

    CBE Life Sci. Educ. 10.1187/cbe.15-02-0032 (2015).

  6. Viral Economics

    All aboard the disease train

    1. Brad Wible

    Expanded transportation networks have increased the transmission of viral diseases in France

    PHOTO: © EVGENY PROKOFYEV/ALAMY STOCK PHOTO

    Economic booms and improved transportation may come with a costly downside: increased transmission of viral diseases. Adda studied 25 years of weekly disease surveillance reports from across France, focusing on influenza, gastroenteritis, and chickenpox. He found that rail-worker strikes, which diminished travel, limited disease transmission, whereas the expansion of high-speed rail to new regions promoted disease spread. The estimated cost of this increased health burden was of the same magnitude as the benefit of improved travel. In times of economic prosperity, travel increased, driving up disease transmission. The impacts of holiday school closures suggest that, although closing schools during outbreaks could limit disease spread, this is not cost-effective in the light of lost learning and subsequent earning.

    Quart. J. Econ., http://ftp.iza.org/dp9326.pdf (2016).

  7. Atomic Physics

    When is an atomic cloud two-dimensional?

    1. Jelena Stajic

    When a three-dimensional (3D) system is flattened into a 2D “pancake,” interactions between its constituents play an enhanced role. To study these effects, atomic physicists trap atoms so that their motion is restricted to a 2D plane. The rule of thumb is that both the chemical potential and the temperature of the system must be well below the strong confinement in the transverse direction (perpendicular to the plane). Now, Dyke et al. show that the rule is a bit more subtle. As they increased the number of atoms in the trap at a fixed interaction strength, the size of the cloud in the transverse direction increased suddenly. This suggests that the system left the strictly 2D regime, even when the conditions above were met.

    Phys. Rev. A 93, 011603(R) (2016).