This Week in Science

This Week in Science

Science  12 Jan 2018:
Vol. 359, Issue 6372, pp. 172
  1. Neuroscience

    The representation of others in space

    1. Peter Stern

    Egyptian fruit bats were used to identify a brain region that recognizes fellow individuals.

    CREDIT: IVAN KUZMIN/ALAMY STOCK PHOTO

    Different sets of neurons encode the spatial position and orientation of an organism. However, social animals need to know the position of other individuals for social interactions, observational learning, and group navigation. Surprisingly, very little is known about how the position of other animals is represented in the brain. Danjo et al. and Omer et al. now report the discovery of a subgroup of neurons in hippocampal area CA1 that encodes the presence of conspecifics in rat and bat brains, respectively.

    Science, this issue p. 213, p. 218

  2. Solid-State Physics

    Neutrons peek into f-electron bands

    1. Jelena Stajic

    Neutron scattering can be used to tease out the details of collective magnetic excitations that yield well-defined peaks in the data. In principle, it could also be used to look into single-electron band excitations, but collecting enough data to capture broad distributions of intensity is tricky. Goremychkin et al. used neutron spectrometers that could efficiently capture a large amount of data by rotating the sample, a crystal of the intermediate-valence compound CePd3 (see the Perspective by Georges). The measured dynamical magnetic susceptibility, in combination with detailed ab initio calculations, showed the formation of coherent f-electron bands at low temperatures.

    Science, this issue p. 186; see also p. 162

  3. Martian Geology

    Water ice cliffs on Mars

    1. Keith T. Smith

    Some locations on Mars are known to have water ice just below the surface, but how much has remained unclear. Dundas et al. used data from two orbiting spacecraft to examine eight locations where erosion has occurred. This revealed cliffs composed mostly of water ice, which is slowly sublimating as it is exposed to the atmosphere. The ice sheets extend from just below the surface to a depth of 100 meters or more and appear to contain distinct layers, which could preserve a record of Mars' past climate. They might even be a useful source of water for future human exploration of the red planet.

    Science, this issue p. 199

  4. Hybrid Speciation

    Rapid hybrid speciation in Darwin's finches

    1. Laura M. Zahn

    Galapagos finches have driven hypotheses of how speciation occurs. Most commonly, it is assumed that natural selection separates species originating from a single population on the basis of variation in traits that confer advantages for survival and reproduction. Lamichhaney et al. document a case where cross-species hybridization established a reproductively isolated lineage, which demonstrates a process known as homoploid hybrid speciation in action (see the Perspective by Wagner). The authors used genetic markers and phenotypic analyses to create a pedigree that revealed how a cross-island migrant bred with a native species to form a self-perpetuating hybrid population that was reproductively isolated from both parental species.

    Science, this issue p. 224; see also p. 157

  5. Gut Immunity

    Phagocytes patrol intestinal fungi

    1. Priscilla N. Kelly

    Maintaining a healthy balance of gut bacteria can promote good health. Leonardi et al. show that fungi can also interact with gut immune cells to maintain intestinal well-being. CX3CR1+ mononuclear phagocytes (MNPs) patrol the intestine and promote antifungal immunity. Genetic deletion of CX3CR1 in MNPs caused colitis-like symptoms in mice. CX3CR1 polymorphisms were detected in Crohn's disease patients that were unable to produce antibodies against multiple fungal species. Thus, commensal fungi may be as important as bacteria in maintaining gut health, and antifungal therapy could hold promise for treating intestinal inflammation.

    Science, this issue p. 232

  6. Geology

    Volcanic eruptions in the deep sea

    1. Kip Hodges

    Large subaerial volcanic eruptions are among the most dramatic and intensively studied geological events on our planet, but similar submarine eruptions are less well understood. Carey et al. describe the largest submarine eruption in the past century. In 2012, the Havre volcano erupted off northern New Zealand at ocean depths in excess of 900 meters, producing an enormous raft of pumice—a gaseous froth of silica-rich lava.

    Sci. Adv. 10.1126/sciadv.1701121 (2017).

  7. DNA Damage

    The many roles of ATM

    1. Leslie K. Ferrarelli

    The kinase ATM coordinates the response to DNA damage. Lee et al. report that ATM also coordinates a response to oxidative stress that is independent of its response to DNA damage. Activation of ATM by oxidative stress promoted mitochondrial function and autophagy, thus enabling cell survival through metabolic changes and the clearance of toxic protein aggregates. Thus, the loss of ATM in the neurodegenerative disease ataxia telangiectasia may reflect wide-ranging cellular stresses beyond a defective DNA-damage response.

    Sci. Signal. 10, eaan5598 (2018).

  8. Infection

    Cholera pathogen zaps competition

    1. Caroline Ash

    Many bacterial pathogens inject their hosts with virulence effectors delivered by specialist secretion machines. Vibrio cholerae has a type VI secretion system (T6SS) that can be loaded with protein toxins that target eukaryote host cells or kill competing bacteria. Zhao et al. discovered that mutant V. cholerae lacking a T6SS could not compete against Escherichia coli strains in the mouse gut. In contrast, intact V. cholerae readily gained a foothold in the gut of young mice, pumping up inflammatory immune responses and prompting more violent symptoms.

    Science, this issue p. 210

  9. Porous Materials

    Mesoporous metal-organic frameworks

    1. Phil Szuromi

    The diffusion limitations on gas storage and catalytic reaction of microporous materials can often be overcome if they are incorporated into a mesoporous structure with much larger pores. Shen et al. grew ordered arrays of microcrystals of the ZIF-8 metal-organic framework, in which zinc ions are bridged by 2-methylimidazole linkers, inside a porous polystyrene template. These materials showed higher reaction rates for the Knoevenagel reaction between benzaldehydes and malononitriles and better catalyst recyclability.

    Science, this issue p. 206

  10. Antiviral Immunity

    The interferon boomerang

    1. Anand Balasubramani

    Interferon-α/β receptor (IFNAR)-deficient mice are highly susceptible to viruses, including Zika virus (ZIKV). Previous studies modeled ZIKV infection during pregnancy in mice by crossing Ifnar1−/− females to wild-type males, generating Ifnar1+/− fetuses that retain type I IFN responsiveness. Yockey et al. directly examined the role of fetal type I IFN signaling in protection in this context by crossing Ifnar1−/− females to Ifnar1+/− males. Although Ifnar1−/− fetuses had higher ZIKV titers than Ifnar1+/− fetuses, Ifnar1−/− fetuses survived longer. Furthermore, activation of type I IFN signaling in the placentas of Ifnar1+/− fetuses led to fetal hypoxia, demise, and resorption.

    Sci. Immunol. 3, eaao1680 (2018).

  11. Structural Biology

    Architecture of the TRPM subfamily

    1. Steve Mao

    Transient receptor potential melastatin (TRPM) ion channels constitute the largest TRP subfamily and are involved in many physiological processes. TRPM8 is the primary cold and menthol sensor, and TRPM4 is associated with cardiovascular disorders. Yin et al. and Autzen et al. shed light on the general architecture of the TRPM subfamily by solving the structures of TRPM8 and TRPM4, respectively (see the Perspective by Bae et al.). The three-layered architecture of the TRPM8 channel provides the framework for understanding the mechanisms of cold and menthol sensing. The two distinct closed states of TRPM4, with and without calcium, reveal a calcium-binding site and calcium-binding-induced conformational changes.

    Science, this issue p. 237, p. 228; see also p. 160

  12. Immunology

    Epigenetic modulation of effector T cells

    1. Seth Thomas Scanlon

    The epigenetic states and associated chromatin dynamics underlying the initiation and maintenance of memory and effector CD8+ T cells are poorly understood. Pace et al. found that mice lacking the histone H3 lysine 9 methyltransferase Suv39h1 had markedly reduced antigen-specific effector CD8+ T cell responses to Listeria monocytogenes infection (see the Perspective by Henning et al.). Instead, CD8+ T cells in these mice were enriched for genes associated with naïve and memory signatures and showed enhanced memory potential and increased survival capacity. Thus, Suv39h1 marks chromatin through H3K9me3 deposition and silences memory and stem cell programs during the terminal differentiation of effector CD8+ T cells.

    Science, this issue p. 177; see also p. 163

  13. Crohn's Disease

    A shared history

    1. Orla M. Smith

    Crohn's disease (CD), an inflammatory bowel disease, has a relatively high prevalence in Ashkenazi Jewish populations. Hui et al. conducted genome-wide association analysis in 2066 CD patients and 3633 healthy control individuals of Ashkenazi Jewish ancestry and identified two functional variants in the LRRK2 gene. The LRRK2 gene has been linked previously to the development of Parkinson's disease (PD). The newly discovered LRRK2 variants conferred risk for CD (N2081D) or protection from CD (N551K and R1398H). Analysis of other variants within the LRRK2 locus in 24,570 individuals revealed similar genetic effects between CD and PD in both Ashkenazi Jewish and non-Jewish cohorts. The presence of shared LRRK2 alleles in CD and PD provides insight into disease mechanisms and potential treatments.

    Sci. Transl. Med. 10, eaai7795 (2018).

  14. Astrochemistry

    A specific interstellar aromatic molecule

    1. Keith T. Smith

    Aromatic molecules such as polycyclic aromatic hydrocarbons (PAHs) are known to exist in the interstellar medium owing to their characteristic infrared emission features. However, the infrared emission only indicates the general class of molecule, and identifying which specific molecular species are present is difficult. McGuire et al. used radio astronomy to detect rotational transitions of benzonitrile emitted from a well-known nearby cloud of interstellar gas (see the Perspective by Joblin and Cernicharo). This molecule may be a precursor to more complex PAHs. The identification of benzonitrile sheds light on the composition of aromatic material within the interstellar medium—material that will eventually be incorporated into new stars and planets.

    Science, this issue p. 202; see also p. 156

  15. Malarial Genomics

    Dissecting Plasmodium drug resistance

    1. Laura M. Zahn

    Malaria is a deadly disease with no effective vaccine. Physicians thus depend on antimalarial drugs to save lives, but such compounds are often rendered ineffective when parasites evolve resistance. Cowell et al. systematically studied patterns of Plasmodium falciparum genome evolution by analyzing the sequences of clones that were resistant to diverse antimalarial compounds across the P. falciparum life cycle (see the Perspective by Carlton). The findings identify hitherto unrecognized drug targets and drug-resistance genes, as well as additional alleles in known drug-resistance genes.

    Science, this issue p. 191; see also p. 159

  16. Protein Modification

    Fattening up proteins

    1. Michael A. Funk

    Many eukaryotic proteins are modified by the attachment of lipids, and these modifications can alter how proteins interact with cellular membranes. Rana et al. present x-ray crystal structures of an integral membrane enzyme that appends a fatty acyl chain onto a cysteine residue of target proteins. The enzyme active site is situated at the membrane surface, thus explaining the enzyme's preference for substrates that are already membrane-associated. The structure of a fatty acid-like inhibitor bound within a hydrophobic cavity elucidates the mechanism for the enzyme's acyl chain specificity.

    Science, this issue p. eaao6326

  17. Medicine

    Gene therapy: The power of persistence

    1. Paula A. Kiberstis

    Nearly 50 years after the concept was first proposed, gene therapy is now considered a promising treatment option for several human diseases. The path to success has been long and tortuous. Serious adverse effects were encountered in early clinical studies, but this fueled basic research that led to safer and more efficient gene transfer vectors. Gene therapy in various forms has produced clinical benefits in patients with blindness, neuromuscular disease, hemophilia, immunodeficiencies, and cancer. Dunbar et al. review the pioneering work that led the gene therapy field to its current state, describe gene-editing technologies that are expected to play a major role in the field's future, and discuss practical challenges in getting these therapies to patients who need them.

    Science, this issue p. eaan4672

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