This Week in Science

Science  18 May 2018:
Vol. 360, Issue 6390, pp. 748
  1. Protected Areas

    Protected yet pressured

    1. Sacha Vignieri

    Visitors crowd the hydrothermal sites in the world's first national park, Yellowstone.

    CREDIT: SHARON DAY/SHUTTERSTOCK.COM

    Protected areas are increasingly recognized as an essential way to safeguard biodiversity. Although the percentage of land included in the global protected area network has increased from 9 to 15%, Jones et al. found that a third of this area is influenced by intensive human activity. Thus, even landscapes that are protected are experiencing some human pressure, with only the most remote northern regions remaining almost untouched.

    Science, this issue p. 788

  2. Infectious Diseases

    Mycobacteria and metabolism

    1. Christiana N. Fogg

    Since the discovery of Mycobacterium tuberculosis more than a century ago, great progress has been made in defining mechanisms of host resistance to tuberculosis (TB). In contrast, our understanding of how 90 to 95% of infected individuals live with chronic TB is extremely limited. Tzelepis et al. examined the role of mitochondrial matrix protein cyclophilin D (CypD) in T cells by using a mouse model of M. tuberculosis infection. CypD-deficient mice were more susceptible to infection, despite enhanced M. tuberculosis–specific T cell responses. Specific T cells apparently had no impact on curbing bacterial loads but did substantially increase lung immunopathology.

    Sci. Immunol. 3, eaar4135 (2018).

  3. Thermoelectrics

    SnSe doped a different way

    1. Brent Grocholski

    Heat can be converted into electricity by thermoelectric materials. Such materials are promising for use in solid-state cooling devices. A challenge for developing efficient thermoelectric materials is to ensure high electrical but low thermal conductivity. Chang et al. found that bromine doping of tin selenide (SnSe) does just this by maintaining low thermal conductivity in the out-of-plane direction of this layered material. The result is a promising n-type thermoelectric material with electrons as the charge carriers—an important step for developing thermoelectric devices from SnSe.

    Science, this issue p. 778

  4. Electrochemistry

    A very basic pathway from CO2 to ethylene

    1. Jake Yeston

    Ethylene is an important commodity chemical for plastics. It is considered a tractable target for synthesizing renewably from carbon dioxide (CO2). The challenge is that the performance of the copper electrocatalysts used for this conversion under the required basic reaction conditions suffers from the competing reaction of CO2 with the base to form bicarbonate. Dinh et al. designed an electrode that tolerates the base by optimizing CO2 diffusion to the catalytic sites (see the Perspective by Ager and Lapkin). This catalyst design delivers 70% efficiency for 150 hours.

    Science, this issue p. 783; see also p. 707

  5. Climate Change

    One and a half degrees on biodiversity

    1. Andrew M. Sugden

    Insects are the most diverse group of animals on Earth and are ubiquitous in terrestrial food webs. We have little information about their fate in a changing climate; data are scant for insects compared with other groups of organisms. Warren et al. performed a global-scale analysis of the effects of climate change on insect distribution (see the Perspective by Midgley). For vertebrates and plants, the number of species losing more than half their geographic range by 2100 is halved when warming is limited to 1.5°C, compared with projected losses at 2°C. But for insects, the number is reduced by two-thirds.

    Science, this issue p. 791; see also p. 714

  6. Microbiota

    Benign colonization of the gut

    1. Caroline Ash

    Microbial communities in the gut can be highly individual. What engenders this specificity? The gut characteristically produces gram quantities of immunoglobulin A (IgA) antibody, which is presumed to protect the gut from pathogen attack. Donaldson et al. engineered strains of Bacteroides fragilis, a common human commensal, to modify its surface capsule, which affects its ability to colonize the germ-free mouse gut. Capsule changes altered the capacity of IgA to bind to the different mutants. It seems that this commensal species exploits IgA sticking power specifically to give it a competitive edge and to promote its establishment in the gut.

    Science, this issue p. 795

  7. Gene Regulation

    Profiling transcription—a SLAM dunk

    1. Paula A. Kiberstis

    Identification of the direct target genes of transcription factors could shed light on how healthy cells become malignant. Muhar et al. applied a modified version of a transcript-mapping method called SLAM-seq to identify the target genes of two transcriptional regulators of major interest in cancer research (see the Perspective by Sabò and Amati). The MYC oncoprotein selectively activates transcription of just a few genes, primarily those involved in basic cell metabolism. In contrast, BRD4, a bromodomain-containing protein that is being targeted for cancer therapy, activates transcription of many genes.

    Science, this issue p. 800; see also p. 713

  8. Social Sciences

    Incentives drive disclosure

    1. Philippa J. Benson

    Some scientists disclose their research results before publication, but many others do not. What factors explain such differences? Thursby et al. analyzed survey responses and publication data from 7103 active faculty researchers in the United States, Germany, and Switzerland across nine scientific fields. Perceived norms, competition, and commercial orientation explain 70% of disclosure variation across fields. Results were disclosed before publication by 67.2% of respondents, largely to solicit feedback, but sometimes to attract collaborators. Engineers and computer scientists, for whom commercial interests are important, were the least likely to disclose, whereas social scientists and mathematicians were the most likely.

    Sci. Adv. 10.1126/sciadv.aar2133 (2018).

  9. Quantum Materials

    Better performance under stress

    1. Ian S. Osborne

    Engineering stress or strain into materials can improve their performance. Adding mechanical stress to silicon chips, for instance, produces transistors with enhanced electron mobility. Ghadimi et al. explore the possibility of enhancing the vibrational properties of a micromechanical oscillator by engineering stress within the structure (see the Perspective by Eichler). By careful design of the micromechanical oscillator, and by building in associated stresses, exceptional vibrational properties can be produced. Such enhanced oscillators could be used as exquisite force sensors.

    Science, this issue p. 764; see also p. 706

  10. Nephrology

    Touring the kidney, cell by cell

    1. Paula A. Kiberstis

    Our kidneys play a critical role in keeping us healthy, a fact of which we are reminded several times each day. This organ's cellular complexity has hindered progress in understanding the mechanisms underlying chronic kidney disease, which affects 10% of the world's population. Using single-cell transcriptional profiling, Park et al. produced a comprehensive cell atlas of the healthy mouse kidney (see the Perspective by Humphreys). An unexpected cell type in the collecting duct appears to be a transitional state between two known cell types. The transition from one cell type to the other is regulated by the Notch signaling pathway and is associated with metabolic acidosis. The authors also find that genetically distinct kidney diseases with common clinical features share common cellular origins.

    Science, this issue p. 758; see also p. 709

  11. Biochemistry

    A selective autophagy receptor identified

    1. Steve Mao

    Autophagosomes engulf and degrade cellular components in lysosomes. Degradation of ribosomes is called ribophagy and is an important source of nutrients. Using a recently reported method to isolate lysosomes, Wyant et al. profiled the dynamics of the lysosomal proteome under different nutrient conditions (see the Perspective by Nofal and Rabinowitz). The protein NUFIP1 is an autophagy receptor for ribosomes during starvation-induced ribophagy. NUFIP1 shuttles out of the nucleus and targets its ribosome cargo directly by binding to an autophagosome protein. Loss of NUFIP1 means failure to provide sufficient nucleotides during starvation and, therefore, loss of cells under low nutrient conditions.

    Science, this issue p. 751; see also p. 710

  12. Liquid Crystals

    Finding order in twos

    1. Marc S. Lavine

    In nematic liquid crystals, the local orientation of the molecules hovers around an average direction. The orientational control bestows unusual optical properties. In theory, with the right sort of two-dimensional shape, it should be possible to create nematics with biaxial ordering, but this has proven elusive. Mundoor et al. dispersed colloidal rods into a nematic solvent (see the Perspective by Poulin). Within a range of temperature and concentration, the rods ordered orthogonally to the solvent molecules, thus giving the mixture the type of properties that one would expect from a biaxial liquid crystal.

    Science, this issue p. 768; see also p. 712

  13. Inorganic Materials

    Plastic in the dark

    1. Phil Szuromi

    Inorganic semiconductors, such as silicon and gallium arsenide, are brittle materials. This property means that large single crystals are cleaved into thin sheets. Oshima et al. show that zinc sulfide is, in contrast, a plastic material if deformed in total darkness. Plastic deformation is likely inhibited when light is present because photoexcited charge carriers become trapped at these sites and pin them through electrostatic effects.

    Science, this issue p. 772

  14. Fatty Liver Disease

    Fat, microRNAs, and liver disease

    1. Leslie K. Ferrarelli

    Obesity and high-fat diets are linked to fatty liver disease. One hallmark of disease is repression of the cell-stress protein IRE1α. In livers from mice fed a high-fat diet and from patients with hepatic steatosis, Wang et al. found that IRE1α activity was repressed because of a posttranslational modification called S-nitrosylation. The decrease in IRE1α activity enabled the biogenesis of microRNAs that decreased the levels of enzymes involved in lipid metabolism, leading to lipid accumulation in the liver.

    Sci. Signal. 11, eaao4617 (2018).

  15. Stroke

    Stroke therapy goes local

    1. Mattia Maroso

    The complement system is activated by ischemic stroke to promote tissue repair. However, long-lasting systemic activation causes neurological impairments. Alawieh et al. show that specific local complement inhibition reduced cell death and inflammation and promoted functional recovery in a mouse model of stroke. Complement was targeted by linking a complement inhibitor to an antibody recognizing neoepitopes locally and transiently expressed in the ischemic area of the mouse brain. The targeted neoepitope was overexpressed in the ischemic region of brain tissue from stroke patients, indicating that the same approach might be effective in the clinic.

    Sci. Transl. Med. 10, eaao6459 (2018).

  16. Nanothermometry

    Taking the temperature of hot electrons

    1. Jelena Stajic

    As electronic chips become smaller, efficient heat dissipation becomes a greater challenge. Electrons in such devices quickly accelerate over small distances, becoming “hot”—that is, out of equilibrium with the rest of the system. Weng et al. designed a thermometry probe that measures the effective temperature of hot electrons with a spatial resolution of about 50 nanometers. The method is based on the optical measurement of current noise and provides a glimpse into where heat is naturally dissipated in a working device.

    Science, this issue p. 775