This Week in Science

Science  07 Jul 2017:
Vol. 357, Issue 6346, pp. 43
  1. Psychology

    Developing curricula for developing countries

    1. Gilbert Chin

    Children and an instructor playing the mathematical games

    CREDIT: VRINDA KAPUR, J-PAL SA

    Many children in developing countries grow up in economically poor environments and often also suffer from poorly performing educational systems. Dillon et al. designed inexpensive, locally sourced games—five for mathematics and five for social cognition—for use in preschools in Delhi. They measured the effects of these interventions 3, 9, and 15 months later. Compared with those who played social games, the kids who played math games showed enhanced performance on both nonsymbolic and symbolic math assessments at the 3-month time point. However, only the nonsymbolic improvements persisted for as long as a year.

    Science, this issue p. 47

  2. Zika Virus

    Inherited microcephaly exposes Zika culprit

    1. Caroline Ash

    Microcephaly has been the terrifying hallmark of the recent outbreak of Zika virus (ZIKV) in the Americas. How the virus damages brain development in the fetus is enigmatic. Chavali et al. found that in congenital microcephaly, mutations in a neural precursor protein, Musashi-1 (MSI1), impede RNA binding to neural stem cell targets, resulting in abnormal brain development (see the Perspective by Griffin). MSI1 also binds ZIKV RNA to amplify viral replication in cells. This interaction could put a pregnant woman at risk of giving birth to a microcephalic child. Furthermore, MSI1 is expressed at high levels in the mouse testis, which may explain the sexual transmission of this virus.

    Science, this issue p. 83; see also p. 33

  3. Chemical Physics

    NMR on diamonds gets down to chemistry

    1. Jake Yeston

    Nuclear magnetic resonance (NMR) spectroscopy is immensely useful for chemical characterization, but it requires relatively large amounts of sample. Recent studies have leveraged nitrogen vacancy centers in diamond to detect NMR signals from samples of just a few cubic nanometers, but with low resolution. Aslam et al. optimized this technique to achieve a resolution of 1 part per million—sufficient to distinguish among alkyl, vinyl, and aryl protons in solution (see the Perspective by Bar-Gill and Retzker). They also demonstrated solid-state implementation and fluorine detection.

    Science, this issue p. 67; see also p. 38

  4. Tumor Evolution

    Metastases undergo reconstruction

    1. Paula A. Kiberstis

    Cancer cells from primary tumors can migrate to regional lymph nodes and distant organs. The prevailing model in oncology is that lymph node metastases give rise to distant metastases. This “sequential progression model” is the rationale for surgical removal of tumor-draining lymph nodes. Naxerova et al. used phylogenetic methods to reconstruct the evolutionary relationship of primary tumors, lymph node metastases, and distant metastases in 17 patients with colorectal cancer (see the Perspective by Markowitz). The sequential progression model applied to only one-third of the patients. In the other two-thirds, distant metastases and lymph node metastases originated from independent subclones within the primary tumor.

    Science, this issue p. 55; see also p. 35

  5. Plant Pathology

    Genetic analysis of disease emergence

    1. Pamela J. Hines

    In the 1980s, wheat crops began to fall to the fungal pathogen that causes blast disease. First seen in Brazil, wheat blast last year caused devastating crop losses in Bangladesh. Inoue et al. tracked down the shifting genetics that have allowed the emergence of this potentially global threat to wheat crops (see the Perspective by Maekawa and Schulze-Lefert). Wheat varieties with a disabled resistance gene were susceptible to pathogen strains that affected oat and ryegrass crops. Subsequent genetic changes in the pathogen amped up the virulence in wheat.

    Science, this issue p. 80; see also p. 31

  6. Microbiome

    Diving into the depths of atopic dermatitis

    1. Lindsey Pujanandez

    The genus Staphylococcus is a known driver of atopic dermatitis. Byrd et al. used shotgun metagenomic sequencing to analyze the specific species and strains present at baseline and during flares in pediatric atopic dermatitis. Patients with more mild disease had more S. epidermidis in flares, and those with severe disease were dominantly colonized by clonal S. aureus strains. Bacterial strains from the patients were applied to mouse skin, and strains from severe flares induced T cell differentiation and epidermal thickening. Thus, not all Staphylococcus are equal when it comes to atopic dermatitis.

    Staphylococcus epidermidis is a normally harmless resident on human skin.

    PHOTO: EYE OF SCIENCE/SCIENCE SOURCE

    Sci. Transl. Med. 9, eaal4651 (2017).

  7. Superconductivity

    A deeper look into iron selenide

    1. Jelena Stajic

    In the past 10 years, iron-based superconductors have created more puzzles than they have helped resolve. Some of the most fundamental outstanding questions are how strong the interactions are and what the electron pairing mechanism is. Now two groups have made contributions toward resolving these questions in the intriguing compound iron selenide (FeSe) (see the Perspective by Lee). Gerber et al. used photoemission spectroscopy coupled with x-ray diffraction to find that FeSe has a very sizable electron-phonon interaction. Quasiparticle interference imaging helped Sprau et al. determine the shape of the superconducting gap and find that the electron pairing in FeSe is orbital-selective.

    Science, this issue p. 71, p. 75; see also p. 32

  8. Economics

    How to make traffic worse everywhere

    1. Gilbert Chin

    One policy aimed at improving traffic flows in large cities requires vehicles to carry two or three passengers, usually in lanes or roads set aside for high-occupancy vehicle (HOV) travel. Whether this actually increases speeds depends on how heavily the HOV roads are used and the availability of alternate routes. Hanna et al. took advantage of an abrupt policy change—the elimination of HOV rules—in Jakarta to collect the travel times from Google Maps for HOV and alternate routes before and after the change (see the Perspective by Anderson). They observed a serious worsening of traffic throughout the city.

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

  9. Neurodevelopment

    Following the yellow brick road

    1. Pamela J. Hines

    The adrenal glands affect a variety of processes such as stress responses and metabolism. The mature adrenal gland is formed from multiple tissue sources, including cells of neural origin. Furlan et al. traced the origins of these cells. The cells first become Schwann cell precursors and follow along nerves to travel from the dorsal root ganglia of the spine to the adrenal gland. Once there, the cells differentiate into chromaffin cells. The authors used singlecell transcriptomics to reveal the shifts in functional programs during migration, development, and differentiation.

    Science, this issue p. eaal3753

  10. Topological Matter

    Corner-dwelling topological states

    1. Jelena Stajic

    Computing the electric polarization of a crystal is surprisingly tricky, but it can be tackled with the help of a topological concept, the so-called Berry phase. Extensions to higher multiple moments, such as quadrupole and octupole, are even trickier. Benalcazar et al. built a theoretical framework for dealing with these moments in certain types of solids. In the presence of some crystalline symmetries, the quadrupole moment is quantized, and the corners of the system play host to fractionally charged, topologically protected states. These predictions may be testable in cold atom and photonic systems.

    Science, this issue p. 61

  11. Plant Genomics

    Genomics and domestication of wheat

    1. Laura M. Zahn

    Modern wheat, which underlies the diet of many across the globe, has a long history of selection and crosses among different species. Avni et al. used the Hi-C method of genome confirmation capture to assemble and annotate the wild allotetraploid wheat (Triticum turgidum). They then identified the putative causal mutations in genes controlling shattering (a key domestication trait among cereal crops). They also performed an exome capture–based analysis of domestication among wild and domesticated genotypes of emmer wheat. The findings present a compelling overview of the emmer wheat genome and its usefulness in an agricultural context for understanding traits in modern bread wheat.

    Science, this issue p. 93

  12. Vascular Biology

    Intercellular signal for vasodilation

    1. Wei Wong

    Vasoconstriction must be balanced with vasodilation in the arterioles that supply tissues with blood. The second messenger IP3 has been thought to be the signal that passes from smooth muscle cells through gap junctions to endothelial cells to trigger vasodilation. However, Garland et al. found that Ca2+, rather than IP3, entered vascular smooth muscle cells through voltage-gated Ca2+ channels in response to vasoconstricting stimuli. The Ca2+ ions subsequently passed through gap junctions into endothelial cells and initiated vasodilatory responses that are dependent on this cell type.

    Sci. Signal. 10, eaal3806 (2017).

  13. Infectious Disease

    Function follows form

    1. Angela Colmone

    Congenital human cytomegalovirus (HCMV) is the most common infectious cause of disabilities in newborn infants. It is the leading cause of deafness in children, which highlights the need for a vaccine that can block maternal-fetal transmission of HCMV. Chandramouli et al. report crystal structures of neutralizing antibodies bound to the HCMV pentameric complex (Pentamer), a key determinant of viral entry. These structural and functional studies identify potential entry receptor–binding sites on Pentamer, as well as other functional sites that may serve as targets for vaccine development and antibody and small-molecule therapeutics.

    Sci. Immunol. 2, eaan1457 (2017).