This Week in Science

Science  06 Jan 2017:
Vol. 355, Issue 6320, pp. 35
  1. Volcanology

    Hearing a volcanic plume

    1. Brent Grocholski
    CREDIT: ASSOCIATED PRESS, COLT SNAPP

    Monitoring remote eruptions—such as that of Pavlof Volcano, Alaska, in 2016—is challenging. Fee et al. found that the height of the ash plume during the Pavlof eruption could be inferred from sound waves detected by distant infrasound arrays and measurements of seismic tremor. The use of sound waves for monitoring is uncommon but well suited for remote eruptions, especially when we lack visual or satellite observations.

    Science, this issue p. 45

  2. Oceanography

    Reconciling sea surface temperature records

    1. Kip Hodges

    Effective weather prediction, climate modeling, and marine ecosystem studies benefit from a robust understanding of sea surface temperatures. Unfortunately, because surface temperature measurements are conducted in many ways, the results are often discrepant, reducing the reliability of downstream models that use them. Recently, the U.S. National Oceanic and Atmospheric Administration (NOAA) noted and rectified a systematic error in some data sets. The corrections imply that sea surface temperatures have increased more rapidly than was thought. Hausfather et al. compared the corrected estimates to largely independent data sets not subject to the systematic errors. Their results confirm the NOAA corrections and affirm that rates of sea surface warming are indeed higher than previously reported.

    Sci. Adv. 10.1126/sciadv.1601207(2017).

  3. Coagulation

    This antiplatelet agent is just right

    1. Yevgeniya Nusinovich

    Antiplatelet drugs are commonly used to prevent stroke in high-risk patients. Unfortunately, a frequent side effect of these drugs is excessive bleeding. To improve the safety margin of antiplatelet agents, Wong et al. identified a new target for treatment, a platelet receptor called PAR4. They developed a small-molecule drug and evaluated its efficacy and safety in animal models. The new drug was no less effective and had a much larger therapeutic window than the widely used antiplatelet agent clopidogrel.

    Sci. Transl. Med. 9, eaaf5294 (2017).

  4. Brain Development

    Brain structure and function mature together

    1. Peter Stern

    Face recognition abilities improve as humans age.

    CREDIT: JESSE GOMEZ AND KALANIT GRILL-SPECTOR AT THE VISION AND PERCEPTION NEUROSCIENCE LAB

    Our ability to recognize faces improves from infancy to adulthood. This improvement depends on specific face-selective regions in the visual system. Gomez et al. tested face memory and place recognition in children and adults while scanning relevant brain regions. Anatomical changes co-occurred with functional changes in the brain. Some regions in the high-level visual cortex showed profound developmental maturation, whereas others were stable. Thus, improvements in face recognition involve an interplay between structural and functional changes in the brain.

    Science, this issue p. 68

  5. Superconductivity

    Going cold with Bismuth

    1. Jelena Stajic

    Many elemental metals, such as lead and aluminum, become superconducting at low temperatures. Bismuth, a semimetal with very low carrier density, stays nonsuperconducting down to 10 mK. Prakash et al. performed tricky magnetization measurements to show that pure bulk bismuth does undergo the superconducting transition at a tiny temperature of about 0.5 mK (see the Perspective by Behnia). Because bismuth does not fit neatly into the standard picture of superconductivity, further theoretical work is necessary to explain the findings.

    Science, this issue p. 52; see also p. 26

  6. Plant Evolution

    Shedding light on fossil lantern fruit

    1. Andrew M. Sugden

    The Solanaceae (or nightshades) are one of the best-studied plant families, yet their evolutionary origins have thus far been relatively obscure. Corroborative fossil evidence of molecular phylogenetic divergence dates has been lacking. Wilf et al. present 52-million-year-old fossils of lantern fruits from Argentina, which they ascribe to the modern genus Physalis. These fossil finds suggest a much earlier origin of the lantern fruit lineage and indicate that the Solanaceae may have diversified before the final breakup of the Gondwanan supercontinent.

    Science, this issue p. 71

  7. Cell Division

    Recombination revealed by mapping tails

    1. Guy Riddihough

    Meiosis is a specialized double cell division that generates haploid gametes from diploid parent cells. Meiotic recombination between homologous chromosomes ensures the proper segregation of chromosomes to the daughter cells. Mimitou et al. carried out a genome-wide survey of resection of the ends of DNA double strand breaks in yeast. Resection generates single-stranded tails that are vital for meiotic recombination. The Tel1 kinase promoted initiation of resection. Nucleosomes, which normally package DNA, needed to be disassembled to allow rapid and efficient resection.

    Science, this issue p. 40

  8. Flexible Electronics

    Trapping polymers to improve flexibility

    1. Marc S. Lavine

    Polymer molecules at a free surface or trapped in thin layers or tubes will show different properties from those of the bulk. Confinement can prevent crystallization and oddly can sometimes give the chains more scope for motion. Xu et al. found that a conducting polymer confined inside an elastomer—a highly stretchable, rubber-like polymer—retained its conductive properties even when subjected to large deformations (see the Perspective by Napolitano).

    Science, this issue p. 59; see also p. 24

  9. Structural Biology

    High-resolution insights into the intasome

    1. Kristen L. Mueller

    An essential step in the life cycle of lentiviruses such as HIV-1 is when viral DNA integrates into the host genome, establishing a permanent infection of the host cell. The viral integrase enzyme catalyzes this process and is a major drug target. During viral integration, integrase binds the ends of viral DNA, forming a higher-order structure called the intasome. Passos et al. and Ballandras-Colas et al. used cryo—electron microscopy to solve the structures of the intasomes from HIV-1 and maedi-visna virus (ovine lentivirus), respectively. These structures reveal how integrase self-associates to form a functional intasome and help resolve previous conflicting models of intasome assembly.

    Science, this issue p. 89, p. 93

  10. Bioengineering

    The next era of chemical manufacturing

    1. Nicholas S. Wigginton

    Producing mass quantities of chemicals has its roots in the industrial revolution. But industrial synthesis leads to sizeable sustainability and socioeconomic challenges. The rapid advances in biotechnology suggest that biological manufacturing may soon be a feasible alternative, but can it produce chemicals at scale? Clomburg et al. review the progress made in industrial biomanufacturing, including the tradeoffs between highly tunable biocatalysts and units of scale. The biological conversion of single-carbon compounds such as methane, for example, has served as a testbed for more sustainable, decentralized production of desirable compounds.

    Science, this issue 10.1126/science.aag0804

  11. Noncoding RNA

    A very focused function for lncRNAs

    1. Guy Riddihough

    The human genome generates many thousands of long noncoding RNAs (lncRNAs). A very small number of lncRNAs have been shown to be functional. Liu et al. carried out a large-scale CRISPR-based screen to assess the function of ∼17,000 lncRNAs in seven different human cell lines. A considerable number (∼500) of the tested lncRNAs influenced cell growth, suggesting biological function. In almost all cases, though, the function was highly cell type—specific, often limited to just one cell type.

    Science, this issue 10.1126/science.aah7111

  12. Theoretical Chemistry

    Whither the density in DFT calculations?

    1. Jake Yeston

    The continuing development of density functional theory (DFT) has greatly expanded the size and complexity of molecules amenable to computationally tractable simulation. The conventional metric of success for new functionals has been the accuracy of their calculated energies. Medvedev et al. examined how well these functionals calculate electron density across a series of neutral and cationic atoms (see the Perspective by Hammes-Schiffer). Although historically the accuracies of energy and density have improved in tandem, certain recent functionals have sacrificed fidelity to the true density.

    Science, this issue p. 49; see also p. 28

  13. Planetary Science

    Water ice beneath the surface of Ceres

    1. Keith T. Smith

    The dwarf planet Ceres in the inner solar system is thought to have a crust made of a mixture of rock and ice. Prettyman et al. used neutron and gamma-ray spectroscopy from the Dawn spacecraft to peer below Ceres' surface and map the subsurface composition. They found evidence for water ice across the dwarf planet, with water making up a larger fraction of the material near the poles than around the equator. Together with their measurements of other elements, these results aid our understanding of Ceres' composition and constrain models of its formation.

    Science, this issue p. 55

  14. Evolutionary Biology

    Sweet, but not too sweet

    1. Sacha Vignieri

    Nectar-feeding pollinators, when given a choice, tend to prefer nectar with high concentrations of sugar. Nectar-producing plants, however, tend to produce more dilute nectar. This mismatch between selective force and trait value has long been seen as an evolutionary paradox. Nachev et al. used a dynamic flower array that evolved in real time in a Costa Rican rainforest to show that the “paradox” is, in fact, driven by pollinator choices (see the Perspective by Farris). Bat pollinators based their choices on small, nonlinear differences in nectar sweetness, which led to selection for less sweet nectar overall.

    Science, this issue p. 75; see also p. 25

  15. Archaeology

    The peopling of Tibet

    1. Andrew M. Sugden

    The date of the first permanent human occupation of the high Tibetan Plateau has been estimated at about 3600 years ago, when agriculture became established. Meyer et al. used several dating techniques to analyze sediments at a high-altitude site (4270 m) where human handprints and footprints have been found. Their analysis indicates occupation of the plateau 7400 years ago and possibly earlier. These dates are consistent with the genetic history of Tibetans and suggest that a permanent preagricultural peopling of the plateau was enabled by the wetter regional climate at that time.

    Science, this issue p. 64

  16. Cancer Therapy

    Evading cancer drugs by identity fraud

    1. Paula A. Kiberstis

    Prostate cancer growth is fueled by male hormones called androgens. Drugs targeting the androgen receptor (AR) are initially efficacious, but most tumors eventually become resistant (see the Perspective by Kelly and Balk). Mu et al. found that prostate cancer cells escaped the effects of androgen deprivation therapy through a change in lineage identity. Functional loss of the tumor suppressors TP53 and RB1 promoted a shift from AR-dependent luminal epithelial cells to AR-independent basal-like cells. In related work, Ku et al. found that prostate cancer metastasis, lineage switching, and drug resistance were driven by the combined loss of the same tumor suppressors and were accompanied by increased expression of the epigenetic regulator Ezh2. Ezh2 inhibitors reversed the lineage switch and restored sensitivity to androgen deprivation therapy in experimental models.

    Science, this issue p. 84, p. 78; see also p. 29

  17. Infectious Disease

    In-house thymus protection squad

    1. Angela Colmone

    Circulating antibodies from bone marrow—resident plasma cells help to protect the thymus from infection. Nuñez et al. found that plasma cells that reside in the human thymus produce antibodies that are reactive to common viral proteins. These cells inhabit the thymic perivascular space between the thymic epithelial areas and circulation and may fortify the thymus against pathogen invasion. The plasma cells are maintained in aging individuals, presumably contributing to lifelong thymic protection.

    Sci. Immunol. 1, eaah4447 (2016).

  18. Metabolism

    Breaking down hepatic lipid production

    1. Wei Wong

    Lipid accumulation in the liver, a condition called hepatic steatosis, often develops in metabolic syndromes such as obesity. The de novo synthesis of lipids contributes to lipid accumulation and is inhibited by Lipin1. Shimizu et al. found that Lipin1 that was phosphorylated at specific sites was degraded by a ubiquitin ligase complex containing β-TRCP1. Hepatocytes lacking β-TRCP1 had more Lipin1 and reduced triglyceride content. Moreover, mice deficient in β-TRCP1 were protected against diet-induced fatty liver, suggesting that treatments that target this pathway could prevent hepatic steatosis.

    Sci. Signal. 10, eaah4117 (2016).