Editors' Choice

Science  02 Oct 2015:
Vol. 350, Issue 6256, pp. 53
  1. Reproductive Evolution

    Like mother, like father

    1. Sacha Vignieri

    Genes recruited during “pregnancy” in male seahorses are homologous to those used by females across taxa

    PHOTO: © MARK CONLIN/ALAMY STOCK PHOTO

    Live birth has evolved repeatedly across the major taxonomic groups, but in the vast majority it is the female that does the brooding. The most developed case of gender reversal in brooding occurs among seahorses. In some seahorse species, males not only incubate the eggs internally but develop a pouch structure that is strikingly similar to a uterus in terms of form and function. Whittington et al. produced a detailed transcriptome of the genes up-regulated during pregnancy in male Hippocampus abdominalis and found that those involved in embryo growth and support functions, such as nutrient transport and waste removal, were generally homologous to those seen in pregnant female mammals and reptiles. Thus, it seems that the pregnancy pathway is much the same whether fish or mammal, female or male.

    Mol. Biol. Evol. 10.1093/molbev/msv177 (2015).

  2. Superconduction

    Building a nanowire superconducting qubit

    1. Jelena Stajic

    A major ingredient of a superconducting qubit is a Josephson junction, typically containing an insulator that acts as a bridge (“weak link”) between two superconductors. Larsen et al. and de Lange et al. fabricated superconducting qubits that, instead of an insulator, used a semiconducting nanowire as the weak link. Both groups used InAs nanowires, in one case enclosed in a shell of superconducting Al and in the other contacted by superconducting NbTiN. The researchers controlled the frequency of the qubit—a complex operation in the conventional setup—by simply modulating the carrier concentration of the nanowire with gate voltage. The new architecture may lead to more-scalable quantum computers and address fundamental issues such as the quantum statistics of Majorana fermions.

    Phys. Rev. Lett. 115, 127001; 127002 (2015).

  3. Astronomy

    GRBs not fatal for life in early universe

    1. Keith T. Smith

    Artist's conception of a gamma-ray burst

    PHOTO: ESO/A. ROQUETTE

    A nearby gamma-ray burst (GRB) could hugely damage Earth's atmosphere, triggering a mass extinction. GRBs were more common in the early universe, so they might have prevented the early emergence of complex life. Li and Zhang have tested this idea by calculating how often planets would be struck by a dangerously close GRB. Examining how this changes over time, and between different galaxy types, they show that reasonably safe locations existed even when the universe was a third of its current age. Intriguingly, the most likely safe location is in the outskirts of a massive blue galaxy—just where we find Earth.

    Astrophys. J. 810, 41 (2015).

  4. Water Splitting

    A close look at the catalyst interface

    1. Jake Yeston

    The light-driven splitting of water into hydrogen and oxygen is a widely studied approach toward storing solar energy for use at night and on cloudy days. Hill et al. constructed cells in which n-doped silicon absorbed the light and a cobalt catalyst on top helped accelerate the oxygen-generating half of the reaction. Their goal was to study how the catalyst/silicon interface influenced the cell's photovoltage. By probing the system in both solution and solid-state environments, they discerned a crucial contribution from an SiOx oxide layer between the silicon and cobalt. Noncontinuous cobalt coverage also contributed to an enhanced photovoltage. The results could help guide optimization of this and similar device designs.

    Nat. Mater. 10.1038/nmat4408 (2015).

  5. Neural Crest

    Oh, what places they'll go

    1. Pamela J. Hines

    Neural crest cells originate from the neuroepithelium, but end up scattered throughout the body, serving as progenitors of a variety of cell types ranging from pigment to bone. Scarpa et al. asked how such initially well-behaved cells become individualistic pioneers. The key is a switch in the collection of molecules that the cell uses to hold on to its environment. With this switch, the neural crest cell's ability to hold on to neighboring neural crest cells weakens at the same time as its ability to hold on to other substrates strengthens. The shifted balance of power tears apart neighboring cells and favors pathways to new territory. As for adolescents' yearning to leave home, the pull of the horizon weakens anchors at the birthplace.

    Migrating neural crest cells reach for new substrates (magenta) as their cell-cell holds (cyan) decrease

    PHOTO: SCARPA ET AL., DEVELOPMENTAL CELL (24 AUGUST 2015) © 2015 CELL PRESS

    Dev. Cell 34, 421 (2015).

  6. Microbiome

    The most wanted and most fastidious

    1. Caroline Ash

    Cataloging of the human microbiota is continuing apace, but our functional knowledge of the key organisms is woeful. Ó Cuív et al. have exploited bacterial sex, or conjugation, to isolate and genetically manipulate a broad range of the functionally important Firmicute bacteria from mixed human fecal cultures. The recombinant pEHR5 vectors are stably maintained and can be used to fluorescently label some of the Clostridium-group bacteria, which are poorly understood organisms, despite several species being earmarked as desirable for a healthy gut community. This technique will allow the integration of metagenomics with bacterial genetics and paves the way to discovering what these organisms do and where in the gut they do it.

    Sci. Rep, 10.1038/srep13282 (2015).

  7. Antibiotics

    Triple threat

    1. Lisa D. Chong

    Methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide threat to human health, because it is resistant to a large class of β-lactams (penicillins) and to second-generation penicillins, including methicillin. However, Gonzales et al. report that combining different classes and generations of these drugs could be effective in fighting MRSA. A 1:1:1 mix of three compounds—a β-lactam, a carbapenem, and a β-lactamase inhibitor—synergistically targeted bacterial cell wall synthesis and was bactericidal against 73 different clinical isolates of MRSA. The drug combination prevented MRSA from acquiring resistance to the mix and cleared infection in a mouse model of lethal MRSA. The finding opens the prospect of using already–clinically approved drugs to treat multidrug resistant infections.

    Nat. Chem. Biol. 10.1038/nchembio.1911 (2015).

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