Editors' Choice

Science  09 Aug 2019:
Vol. 365, Issue 6453, pp. 555
  1. Plant Science

    Protecting orange groves

    1. Pamela J. Hines

    Citrus greening disease is afflicting harvests and killing trees worldwide.

    PHOTO: JOE RAEDLE/GETTY IMAGES

    Orange trees around the globe are succumbing to devastating disease. In groves worldwide, from China to Brazil, a psyllid bug transmits a motile bacterium that causes citrus greening disease. Infected trees produce bitter fruit and die prematurely. Taylor et al. have analyzed environmental variables that correlate with the presence of citrus greening disease. It seems that the disease is favored at average temperatures of 25°C. Mapping of citrus-compatible growing regions globally with temperature patterns predicts where future citrus groves might be more resistant to citrus greening disease and which existing citrus groves might be most defensible.

    J. Appl. Ecol. 56, 2057 (2019).

  2. Cell Biology

    Making and breaking contacts

    1. Stella M. Hurtley

    Within our cells, mitochondria frequently make contact and undergo fission and fusion events to regulate the mitochondrial network. Mitochondrial contact is important for normal cellular metabolism. Wong et al. used super-resolution live-cell imaging to examine intermitochondrial contacts sites in human cell lines. They found that intermitochondrial contact restricts the motility of individual mitochondria within the cell but can be modulated. Lysosome contact promotes mitochondrial untethering by RAB7 guanosine triphosphate (GTP) hydrolysis. By contrast, contact with endoplasmic reticulum (ER) does not prompt decoupling, although ER tubules marked intermitochondrial untethering events. Multiple lysosomal and mitochondrial GTPases appear to coordinate to regulate mitochondrial contact dynamics. If these dynamics are disrupted by mutation, for example, in cells from patients with the hereditary neuropathy Charcot-Marie-Tooth disease, mitochondrial contacts are slower to disassemble. This results in dysfunctional mitochondrial dynamics, which culminates in axonal degradation.

    Dev. Cell 50, 339 (2019).

  3. Plant Ecology

    The buzz about flowers

    1. Laura M. Zahn

    The beach evening primrose, Oenothera drummondii

    PHOTO: DANIEL DEMPSTER PHOTOGRAPHY/ALAMY STOCK PHOTO

    Plants are often thought of as rather passive organisms. However, they can actively respond to environmental cues to promote their own survival. Veits et al. show that at least one plant species responds to the sounds of bees in a way that enhances their attractiveness to pollinators. The authors exposed matforming beach evening primrose plants to recordings of the sounds of flying bees. The flowers appeared to “hear” the bees and vibrated in response to bee noise but not in response to higher-frequency sounds. The flowers then rapidly produced nectar with a higher sugar concentration, which is assumed to increase pollinator visitation and thereby actively promote the plant's reproductive success.

    Ecol. Lett. 10.1111/ele.13331 (2019).

  4. Materials Science

    Hard but flexible coatings

    1. Marc S. Lavine

    Early coatings for display devices were based on inorganic glassy materials made from condensation reactions of alkoxysilyl groups. Although these provided scratch and wear resistance, they were brittle and not flexible—a typical trade-off seen for hard materials. Seo et al. circumvent this limitation by reacting 2-(triethoxysilyl)propyl isocyanate onto the ring part of an α-cyclodextrin–based polyrotaxane molecule. Once crosslinked using a random copolymer, the modified α-cyclodextrin rings are still able to slide along the polyrotaxane backbone, thus imparting flexibility to the hard film. In addition to providing hardness and scratch resistance, a coated surface could also be bent repeatedly without defect formation.

    ACS Appl. Mater. Interfaces 11, 27306 (2019).

  5. Cancer

    Perilous traffic

    1. Paula A. Kiberstis

    Proper trafficking of proteins across the nuclear envelope is essential for many cellular functions. A subset of human cancers harbor somatic mutations in the XPO1 gene, which encodes exportin-1, part of the cell machinery regulating nuclear export. These genomic data suggest that disruption of nucleocytoplasmic trafficking might contribute to tumorigenesis. Taylor et al. studied the functional consequences of the most recurrent XPO1 mutations and found that the mutations are sufficient to drive oncogenic transformation in model systems. Mechanistically, the mutations alter the ability of exportin-1 to engage protein cargo for nuclear export, which in turn alters the nucleocytoplasmic distribution of hundreds of proteins. Several of these proteins are components of key signaling pathways that regulate cell proliferation.

    Cancer Discov. 10.1158/2159-8290.CD-19-0298 (2019).

  6. Diversity

    What's in a name?

    1. Melissa McCartney

    How do gender and race stereotypes influence who is selected for postdoctoral positions? Eaton et al. asked biology and physics professors to read one of eight identical curriculum vitae (CV) of hypothetical postdoctoral applicants, whose names had been manipulated for race and gender, and rate them for competence, hire-ability, and likeability. Although women were rated more likeable than men across departments, physics faculty rated male candidates as more competent and more hirable. Both physics and biology faculty rated Asian and White candidates as more hirable than Black and Latinx candidates. Taken together, this study provides additional experimental support to the double-blind challenges faced by women of color in science and helps to expose faculty biases that may impede minority members from advancing in STEM.

    Sex Roles 10.1007/s11199-019-01052-w (2019).

  7. Nanomaterials

    Photodriven chiral nanoparticle assembly

    1. Phil Szuromi

    Circularly polarized (CP) light can drive the synthesis of chiral small molecules and polymers. Kim et al. now show that photoreduction of a solution of a gold(III) salt (HAuCl4) and citrate with green CP laser light (543 nanometers) produces chiral gold nanocolloids. Initially, gold nanoparticles (about 3 nanometers in diameter) form and then assemble into chiral clusters. Red solutions had circular dichroism (CD) peak at 550 nanometers (the gold plasmon resonance) that changed sign for assemblies made with left- or right-handed CP light. The CD spectra could be quantitatively modeled on the basis of the irregular shapes revealed by electron tomography of these nanocolloids.

    J. Am. Chem. Soc. 141, 11739 (2019).