Editors' Choice

Science  17 Apr 2015:
Vol. 348, Issue 6232, pp. 299
  1. Immunogenetics

    Of mice and men

    1. Laura M. Zahn

    Selection has shaped immune responses differently in humans and mice

    PHOTO: © JIM CORWIN/ALAMY

    Species undergo different selective forces, and those that drive immunity are of special interest because they may affect studies of human health. Webb et al. investigated the differences between human and mouse for 456 protein-coding gene families involved in innate immunity. Of these, 2 genes in humans and 35 genes in mice exhibited signatures of positive selection. Examining the evolutionary distance between mice and humans, they further identified many genes likely to be under positive selection in the primate and murid lineages. These changes, for the most part, appear to have been fixed within humans and mice, respectively, demonstrating the different evolutionary trajectories that immune genes have taken during evolution.

    Mol. Biol. Evol. 10.1093/molbev/msv051 (2015).

  2. Protein Folding

    Interfering in an aggregation pathway

    1. Valda Vinson

    Most dementia cases are caused by neurodegenerative Alzheimer's disease. Plaques composed of fibrils of a 42-residue amyloid-β peptide (Aβ42) are characteristic of this disease. There is evidence that neurotoxicity is caused by Aβ42 oligomers rather than the fibrils, but fibrils catalyze the formation of oligomers. Cohen et al. show that the human chaperone domain Briochos binds to the surface of Aβ42 fibrils and prevents them from catalyzing oligomer formation. In electrophysiology experiments in mouse brain slices, Briochos prevented the inhibition of neural oscillations caused by Aβ42 aggregation. In this case, a chaperone acts not by promoting folding or preventing misfolding but by targeting a nucleation step in the aggregation pathway.

    Nat. Struct. Mol. Biol. 10.1038/nsmb.2971 (2015).

  3. Physics

    Shocking aluminum into a warm dense state

    1. Jelena Stajic

    Simulation of warm dense matter topology

    CREDIT: L. B. FLETCHER ET AL. NATURE PHOTONICS 9 (23 MARCH 2015) © NATURE PUBLISHING GROUP

    In some extreme environments (such as the interior of Saturn, for example), matter is a dense soup of strongly interacting particles: “warm dense matter” by name. Scientists can create this regime in the laboratory by hitting a material with powerful laser beams, causing shock waves that lead to melting. Fletcher et al. monitored the properties of a thin sample of aluminum as it transformed from a solid into warm dense matter, its density more than doubling in the process. Using x-ray scattering and comparing their results to model calculations, they found that short-range repulsive interactions between ions played a major role in the transition.

    Nat. Photon. 10.1038/nphoton.2015.41 (2015).

  4. Education

    Out with tradition and in with inquiry

    1. Melissa McCartney

    Replacing traditional chemistry labs with inquiry-based laboratories that mimic a research project is no easy feat. Hartings et al. describe the creation and assessment of two, two-semester-long, student-driven, faculty-assisted laboratory curricula. What makes this approach unique is that the students control the research direction. Research done in the first semester is considered to be a control experiment forming the basis for the second semester, which is then dictated by the expertise and interest of the researchers. The research trajectory continues as the second-semester experiments from one year become the control experiments for the next year. This allows the research project to continually evolve according to student decisions, making it a research project that truly belongs to students.

    J. Chem. Educ. 10.1021/ed500793q (2015).

  5. Cell Biology

    Keeping the cell nucleus pumped up

    1. Guy Riddihough

    The nucleus is the most prominent organelle inside eukaryotic cells. It is often roughly spherical in shape and houses the genomic DNA. Nuclear Lamins are important for maintaining nuclear shape, and deformed nuclei are often associated with premature aging diseases. Verboon et al. find that the fruit fly gene washout (wash), involved in maintaining endosome shape in the cytoplasm, is also required to maintain the smooth spherical shape of the nucleus. Wash protein interacts with Lamin and is associated with heterochromatin in the nucleus. It also helps organize chromosomes and subnuclear domains, such as the nucleolus and cajal bodies.

    Curr. Biol. 25, 804 (2015).

  6. Antibiotic Resistance

    Challenging antimicrobial growth trends

    1. Caroline Ash

    Antimicrobial use in animal production could exceed 100,000 tons a year by 2030. Chronic use of growth-promoting antimicrobials in farming has selected for resistant bacteria that have spread into humans. Facing the reluctance of the food and veterinary industries to report on antimicrobial sales, Van Boeckel et al. used statistical models to map and project global antimicrobial consumption. By far the biggest current and future consumer is China, followed by the United States, but Brazil, India, and Mexico also are or soon will be major users, along with other transitional countries seeking to intensify animal production for their increasingly affluent societies who are demanding more meat to eat.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1503141112 (2015).

  7. Speciation

    Not a panacea

    1. Sacha Vignieri

    Though morphologically distinct, the three species of Holarctic redpolls, including this hoary redpoll, display almost no genetic divergence

    CREDIT: © ALL CANADA PHOTOS/ALAMY

    Emerging genetic technologies, such as single-nucleotide anonymous markers (SNPs), have provided incredible insight about speciation. Mason and Taylor used hundreds of thousands of SNPs in conjunction with gene expression and niche modeling to define patterns of speciation in the Holarctic redpoll species flock, which consists of three morphologically distinct species in the genus Acanthis. Despite the large number of loci, they found almost no genetic divergence among the three species, although they did reveal differences in gene expression and slight differences in niche use. They suggest that speciation in this group may be on-going, perhaps driven by small ecological shifts, and argue that even high-powered genetic techniques may not be able to uncover a species' whole story.

    Mol. Ecol. 10.1111/mec.13140 (2015).

Navigate This Article