This Week in Science

Science  30 Oct 2015:
Vol. 350, Issue 6260, pp. 524
  1. Primate Evolution

    Meet your gibbon cousin

    1. Sacha Vignieri

    Well-preserved cranium from the Pliobates partial skeleton

    PHOTO: INSTITUT CATALÀ DE PALEONTOLOGIA MIQUEL CRUSAFONT (ICP)

    Apes are divided into two groups: larger-bodied apes, or hominoids, such as humans, chimps, and gorillas; and smaller-bodied hylobatids, such as gibbons. These two lineages are thought to have diverged rather cleanly, sharing few similarities after the emergence of crown hominoids. Alba et al. describe a new ape from the Miocene era that contains characteristics from both hominoids and small-bodied apes (see the Perspective by Benefit and McCrossin). Thus, early small-bodied apes may have contributed more to the evolution of the hominoid lineage than previously assumed.

    Science, this issue p. 10.1126/science.aab2625; see also p. 515

  2. Batteries

    Solving the problems with Li-air batteries

    1. Marc S. Lavine

    Li-air batteries come as close as possible to the theoretical limits for energy density in a battery. By weight, this is roughly 10 times higher than conventional lithium-ion batteries and would be sufficient to power cars with a range comparable to those with gasoline engines. But engineering a Li-air battery has been a challenge. Liu et al. managed to overcome the remaining challenges: They were able to avoid electrode passivation, turn limited solvent stability into an advantage, eliminate the fatal problems caused by superoxides, achieve high power with negligible degradation, and even circumvent the problems of removing atmospheric water.

    Science, this issue p. 530

  3. Geomorphology

    Bedrock weathering runs to the hills

    1. Brent Grocholski

    Fractures in bedrock drive the breakdown of rock into soil. Soil makes observations of bedrock processes challenging. St. Clair et al. combined a three-dimensional stress model with geophysical measurements to show that bedrock erosion rates mirror changes in topography (see the Perspective by Anderson). Seismic reflection and electromagnetic profiles allowed mapping of the bedrock fracture density. The profiles mirror changes in surface elevation and thus provide a way to study the critical zone between rock and soil.

    Science, this issue p. 534; see also p. 506

  4. Magnetism

    Visualizing conducting domain walls

    1. Jelena Stajic

    When a metal undergoes a phase transition and becomes insulating, it sometimes also becomes magnetically ordered. It is possible that some metallicity survives along the boundaries of magnetic domains, the so-called domain walls, but the question is difficult to address directly in experiments. Ma et al. did just that by mapping out the conductance of the material Nd2Ir2O7 in its low-temperature magnetic insulating phase, using microwave impedance microscopy. The magnetic domain walls showed up clearly in the images as regions of high conductance.

    Science, this issue p. 538

  5. Chronic Itch

    A circuit controlling mechanical itch

    1. Peter Stern

    Considerable progress has been made in understanding and treating chemically induced itch. However, little is known about the mechanisms underlying mechanically evoked itch. Bourane et al. produced a model of mechanical itch by reducing the number of neuropeptide Y–expressing inhibitory spinal interneurons. This led to a selective increase in mechanically evoked itch-like behavior in mice. In contrast, chemically evoked itch or pain behavior remained unaffected.

    Science, this issue p. 550

  6. Virology

    A close up view of retrovirus spreading

    1. Kristen L. Mueller

    Viral infections typically begin with a small number of viral particles gaining access to the host at a specific tissue site. But how do viruses that cause systemic infections, such as HIV, spread more widely? Sewald et al. visualized how the retroviruses murine leukemia virus (MLV) and HIV spread within lymph nodes in mice (see the Perspective by Hope). Specific macrophages that line the lymph-draining sinuses in lymph nodes first captured the virus using the carbohydrate-binding protein CD169. These macrophages subsequently transferred virus to the B1 subclass of B lymphocytes, which migrated further into the lymph node, disseminating the virus more widely.

    Science, this issue p. 563; see also p. 511

  7. Lung Disease

    Anticoagulant “morfs” into pneumonia therapy

    1. Orla M. Smith

    Pneumonia can cause lung cell death, yet the mechanisms by which infection reduces cell viability are unclear. Zou et al. found that a poorly described protein, Morf4l1, triggers cell death in mice with pneumonia. The half-life of Morf4l1—normally a short-lived protein—was increased in the context of pneumonia. The anticoagulant drug Argatroban blocked half-life extension as well as the injurious actions of Morf4l1, thus prolonging the survival of mice with experimental pneumonia.

    Sci. Transl. Med. 7, 311ra171 (2015).

  8. Economics

    Comparing lab and field estimates

    1. Gilbert Chin

    What do Swiss high-school students and Eastern European seasonal laborers have in common? When the former are tasked with stuffing questionnaires into envelopes in a classroom setting and the latter are employed to pick fruit in the United Kingdom, both work harder in the presence of their peers. Herbst and Mas reanalyzed the results of 35 such studies, either experiments carried out under controlled conditions or empirical studies based on data collected in the field (see the Perspective by Charness and Fehr). Encouragingly, they found that the magnitude of the spillover effect—how much harder a worker works when other workers are alongside—was the same.

    Fruit pickers collect the harvest in the United Kingdom

    PHOTO: JOHN GILES/PA WIRE

    Science, this issue p. 545; see also p. 512

  9. Reproductive Biology

    Ensuring a speedy labor, STAT!

    1. Leslie K. Ferrarelli

    The amnion is one of the membranes that surround the fetus. In the amnion, cortisol enhances the activity of the enzyme COX-2, which produces prostaglandins that trigger changes in uterine smooth muscle that enable delivery. Wang et al. used amnion fibroblasts from full-term births from women who delivered after active labor or through cesarean section (see the Focus by Zannas and Chrousos). They found that the glucocorticoid receptor interacted with the transcription factor STAT3 to promote transcription of the gene encoding COX-2, amplifying cortisol-triggered prostaglandin production.

    Sci. Signal. 8, ra106; fs19 (2015).

  10. Risk Assessment

    Setting policy, knowing risks

    1. Barbara R. Jasny

    Policy-makers often commission formal analyses to estimate the costs, risks, and benefits of proposed projects or policies. Applications range from estimating the risks of commercial nuclear power, to setting priorities among environmental risks, to comparing technologies for generating electricity, to weighing the benefits and risks of prescription drugs. In the United States, analyses are required for all major federal regulations. Fischhoff reviews how such analyses are limited by the scientific and ethical judgments inherent in the process and require collaboration between those who generate the analyses and those who want to use them.

    Science, this issue p. 10.1126/science.aaa6516

  11. Structural Biology

    Chromosome-capping enzyme complex

    1. Guy Riddihough

    Telomeres cap and protect the ends of our chromosomes. The telomerase complex helps maintain the telomere DNA repeat sequences. Telomerase consists of an RNA and a number of protein subunits. Jiang et al. used cryo–electron microscopy and x-ray crystallography to determine the structure of the Tetrahymena telomerase complex. The telomerase is made up of three subcomplexes, which include two previously unknown protein subunits in addition to the seven known subunits. The structures also reveal the path of the RNA component in the telomerase catalytic core.

    Science, this issue p. 10.1126/science.aab4070

  12. Superconductivity

    Cooling to see the effects of disorder

    1. Jelena Stajic

    In sufficiently strong external magnetic fields, thin superconducting films typically become insulating. The presence of disorder can affect this phase transition. Theorists have proposed that disorder can cause the so-called Griffiths singularity, where the behavior of the system is determined by a small number of superconducting islands that form above the critical magnetic field. Xing et al. observed a signature of such a singularity in thin films of gallium by analyzing transport data taken at very low temperatures (see the Perspective by Markovic). In this regime, thermal fluctuations were not strong enough to homogenize the system, which allowed the rare islands to form.

    Science, this issue p. 542; see also p. 509

  13. Brain Development

    Circuits for brain building

    1. Pamela J. Hines

    The brain is made up of circuits. Chen and Kriegstein analyzed how one particular circuit functions differently in developing and mature mouse brains (see the Perspective by Spitzer). This circuit connects the brain's diencephalon to the cortex. Early in development, the circuit is excitatory and affects how the cortical neurons it touches build their dendrites and synapses. Later on, after the fundamentals of brain construction are in place, the circuit switches to inhibitory functions, helping the brain resist epileptiform activity.

    Science, this issue p. 554; see also p. 510

  14. Microbiome

    The benefits of Escherichia coli

    1. Caroline Ash

    Infection and intestinal damage can trigger severe muscle wasting and loss of fat in mice. How this happens is poorly understood. Palaferri Schieber et al. discovered a protective Escherichia coli strain in their mouse colony. Mice intestinally colonized with the E. coli and infected with the food-poisoning bug Salmonella or with the lung pathogen Burkholderia did not waste away. Without the E. coli, similarly infected mice became fatally ill. The protective E. coli stimulated an innate immune mechanism that ensured that muscle-signaling pathways were not damaged by infection. Thus, the friendly E. coli allowed its host to tolerate and survive the pathogens.

    Science, this issue p. 558

  15. Tumor Viruses

    Viral oncogenes remove the host's STING

    1. Kristen L. Mueller

    Cancer-causing viruses, such as the human papilloma virus (HPV) that causes cervical cancer, account for 12% of human cancers. One way they can cause cancer is by targeting tumor suppressor proteins in the host. Now Lau et al. report that DNA tumor viruses can also thwart the host's immune system. Oncogenes from HPV and human adenovirus bound to the protein STING, a key component of the cGAS-STING pathway that senses and defends against intracellular DNA. In this way, the viruses subvert the host's antiviral immunity and set up shop, which, for an unlucky few, eventually causes cancer.

    Science, this issue p. 568

  16. Ecology

    Reversing the butterfly effect

    1. Barry Pogson

    In the 1970s, “Does the flap of a butterfly's wings in Brazil set off a tornado in Texas?” was a provocative seminar title that reached the public psyche. What of the converse? How will climate change affect butterfly populations? Palmer et al. extended the strategy of looking at bellwether species to bellwether taxa, in order to better analyze the impact of 40 years of climate variability on the abundance of 23 butterfly and 131 moth species. Over half of the changes in the abundance of a species across the United Kingdom reflected species-specific exposure and sensitivity to climate. The findings suggest that we need to rethink early–21st-century assumptions about the effect of climate change on butterflies; many species thought to benefit from warming trends will in fact decline in abundance.

    Sci. Adv. 10.1126/sciadv.1400220 (2015).

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