Editors' Choice

Science  02 Dec 2016:
Vol. 354, Issue 6316, pp. 1115
  1. Insect Genomics

    Acquiring the genes to digest wood

    1. Laura M. Zahn

    Asian longhorned beetle larvae digest wood by using acquired genes.

    PHOTO: SCOTT CAMAZINE / ALAMY STOCK PHOTO

    The larvae of the invasive Asian longhorned beetle burrow into and kill trees. On sequencing the genome, McKenna et al. found that gene transfers from fungi and bacteria, followed by functional evolution and gene family expansions, appear to have conferred the ability to the beetles to find plants, digest cellulose, and nullify harmful compounds made by the plants. Interestingly, other wood-feeding beetles appear to have undergone a similar evolutionary trajectory, one that is distinct from that of wood-feeding insects such as termites.

    Genome Biol. 17, 227 (2016).

  2. Plant Biology

    Targeting tip growth

    1. Pamela J. Hines

    Tip growth, which characterizes cells as diverse as root hairs and brain neurons, depends on secretory vesicles to add new plasma membrane in a defined subdomain. Bloch et al. show that in growing Arabidopsis pollen tubes, the exocyst subunit SEC3a is a target for secretory vesicles at the tip. SEC3a localization defines the axis of growth and the domain where new pectin is added to the cell wall. Pollen tubes of tobacco, which are fatter than those of Arabidopsis, showed more complex patterns: During isotropic growth, SEC3a was distributed in a broad subapical domain, whereas during rapid elongation growth, SEC3a was localized to the apical tip.

    Plant Physiol. 172, 980 (2016).

  3. Cell Biology

    Getting an UPR hand on recovERy

    1. Stella M. Hurtley

    The endoplasmic reticulum (ER) is an intracellular membranous labyrinth that provides the entry point to the secretory pathway. During proteotoxic stress, the ER expands to cope with the added burden of misfolded or unfolded proteins. This is termed the unfolded protein response (UPR). Fumagilli et al. asked how, after the stress is removed, the cell returns its ER to normal levels. In cultured mammalian cells, they uncovered a process called “recovER-phagy.” During recovER-phagy, excess ER membranes are targeted for destruction. Unexpectedly, a component of the ER protein translocation machinery, Sec62, appears to provide a key autophagy receptor in this process, independently of its canonical function.

    Nat. Cell Biol. 18, 1173 (2016).

  4. Human Biology

    Neuron development in human embryos

    1. Sarah Harrison

    Mammalian fertility depends on the secretion of gonadotropin-releasing hormone (GnRH) from a population of specialized neurons residing in the hypothalamus. During embryogenesis, these neurons develop at the olfactory placodes, and they subsequently migrate to the brain. Very little is known about the process in humans, however. Casoni et al. have studied this in depth by using donated human embryonic tissue. They tracked the differentiation and migration of GnRH neurons through the first trimester of gestation by examining samples at different developmental stages and identified important differences between humans and rodents. Unexpectedly, they also found that some of these neurons migrate to extra-hypothalmic regions of the brain, suggesting that they play roles in other processes not linked to fertility

    Development 10.1242/dev.139444 (2016).

  5. Animal Development

    Keeping tissue layers separate

    1. Sarah Harrison

    Corals share gastrulation signals for mouth-anus development with vertebrates.

    PHOTO: ALEXANDER SEMENOV

    Keeping tissue layers separate Gastrulation is the conversion of an embryo from a single sheet of pluripotent cells into a structure with multiple tissue layers. This process establishes the future body plan and is highly conserved among metazoans. In vertebrate embryos, the transcription factor Brachyury delineates the middle tissue layer (the mesoderm) from the outer (ectoderm) and the inner (endoderm) layers. Yasuoka et al. discovered that in coral embryos, which lack a mesoderm, brachyury is regulated by the same signaling pathway as that found in vertebrates. In corals, it demarcates ectoderm from endoderm and is essential for the development of the mouth-anus

    Curr. Biol. 26, 2885 (2016).

  6. Robotics

    Autonomously eat, digest, move, repeat

    1. Marc S. Lavine

    Truly autonomous robots require a robust and independent way to move and a means to harvest energy from the environment. Philamore et al. push toward these goals by devising a soft robotic mouth for use in aquatic environments that gathers organic biomass, which is processed in a microbial fuel cell to generate useful energy. Origami-like folding of a membrane pulls particulate-laden water into the mouth; the mouth is then closed for operation of the microbial fuel cell, which can be isolated from the water and connected in series. When combined with state-of-the-art electronics, the energy output from the fuel cell was boosted to usable values for powering motors and artificial muscles within the robot.

    Soft Robotics 10.1089/soro.2016.0020 (2016).

  7. Neuroscience

    Side effects for placebo poppers

    1. Caroline Ash

    Patients in clinical trials may see their conditions improve, sometimes dramatically, even when they are in the control arm of the study. Tétreault et al. used brain imaging to analyze the connectivity during placebo and pain relief treatment for arthritis-induced knee pain. Brain activity associated with the placebo effect was recorded in the right midfrontal gyrus circuitry of about half of the participants. In contrast, duloxetine-induced analgesia stimulated activity deep in the right parahippo-campal gyrus. In some patients, duloxetine interfered adversely with the placebo effect. The responses of individuals can now be differentiated, and their exposure to ineffective therapies can be monitored.

    PLOS Biol. 10.1371/journal. pbio.1002570 (2016).