Editors' Choice

Science  17 Oct 2014:
Vol. 346, Issue 6207, pp. 311
  1. Antibiotics

    Charting the course of antibiotic failure

    1. Caroline Ash

    Bacterial resistance to antibiotics is a major public health problem. To better understand this in a clinical setting, Currie et al. analyzed a 20-year prescribing history of antibiotics by UK primary care practitioners and report a 12% increase in treatment failure (when a specific antibiotic fails to cure an infection). The authors found only small decreases in the ability of frontline drugs, such as penicillins and macrolides, to control respiratory tract and soft tissue infections. More worryingly, however, second-line antibiotics, such as cephalosporins and quinolones, often used to treat elderly and frail patients with pneumonia, showed higher failure rates since 1991.

    BMJ 10.1136/bmj.g5493 (2014).

  2. Mammal Digit Number

    Protein sorting sets digit number

    1. Beverly A. Purnell

    Like human fingers and toes, mice have five digits on their front and back paws. To better understand the molecular mechanism behind this, Handschuh et al. studied mice with extra or fused digits caused by a mutation that leads to reduced expression of the protein Vps25. Vps25 helps to sort proteins at the cell surface in a process called endosomal protein trafficking. Such sorting ensures that cells express just the right amount of particular proteins, so things such as tissue development go off without a hitch. In Vps25 mutant mice, cells divided more in hindlimbs, and fewer cells in the spaces between digits died, which suggests that digit development requires that cells sort their proteins properly.

    Cell Reports 10.1016/j.celrep.2014.09.019 (2014).

  3. Mineral Physics

    Unraveling ringwoodite hydration in mantle

    1. Brent Grocholski

    Certain high-pressure minerals in Earth's mantle are likely to contain oceans' worth of water dissolved into their crystal structures. Exactly how water dissolves into ringwoodite, an important mineral in the mantle transition zone, influences our ability to detect mantle water using geophysical tools. Purevjav et al. tackle this problem by using a powerful beam of neutrons to determine the location of hydrogen atoms in the ringwoodite structure. They found that hydrogen substitutes for any of the major cations, dramatically lowering the speed of seismic waves in the mineral. This discovery may make it possible to map important water content variations in the transition zone of Earth's mantle.

    Geophys. Res. Lett. 10.1002/2014GL0614488 (2014).

  4. Paleontology

    Meat-eater lived in extinction's wake

    1. Sid Perkins

    A newly described dinosaur unearthed in Venezuela is a close relative of creatures that later evolved into giant meat-eaters such as Allosaurus and Tyrannosaurus rex. Langer et al. examined two lower leg bones from two different individuals of Tachiraptor admirabilis. The two bones were different enough from those of known species to mark the creature as new. T. admirabilis was a theropod, measuring 1.5 meters from nose to tail. The bones were found in an ancient flood plain, in sediments deposited 200.7 million years ago—less than 1 million years after the mass extinction that marked the end of the Triassic period and the beginning of the Jurassic.

    Roy. Soc. Open Sci. 10.1098/rsos.140184(2014).

  5. Behavioral Science

    A costly reluctance to speak out

    1. Gilbert Chin

    Decision-making in groups depends not only on whether any of the group members knows the right answer but also on whether the most informed members actually speak up. Coffman examined the propensity to contribute one's ideas in a pared-down laboratory knowledge test in which other factors, such as discrimination and argumentativeness, do not play a role by design. She found that undergraduate women contribute their answer to the group less often than undergraduate men. The authors observed that this was subject area–dependent: women showed the least amount of reluctance for the most femalestereotyped subject area, arts, and the greatest amount for the most male-stereotyped subject, sports.

    Quart. J. Econ. 129, 10.1093/qje/qju023 (2014).

  6. Limnology

    How many lakes are there on Earth?

    1. Julia Fahrenkamp-Uppenbrink

    Most maps or databases of global lakes either omit small lakes or estimate their numbers, leaving accurate calculations of their net subaerial coverage uncertain. This makes it difficult to determine the role of lakes in Earth's carbon cycle. Verpoorter et al. use high-resolution satellite images to create a database of all lakes with surface areas greater than 2000 square meters. The interpretation of satellite images can be hampered by the presence of features such as dark forests or mountain shadows, so the authors developed a special algorithm to overcome these problems. They conclude that there are 117 million lakes, covering 3.7% of Earth's land area not covered by ice. They conclude that there are fewer lakes, but that those lakes cover more area, than previous estimates have indicated.

    Geophys. Res. Lett. 10.1002/2014GL060641 (2014).

  7. Infectious Disease

    Taking the temperature of virulence

    1. Barbara R. Jasny

    Cholera kills more than 100,000 people yearly and results from consuming food or water contaminated with Vibrio cholerae. The bacterium only expresses virulence factors, proteins that cause disease, when it infects people. Weber et al. investigated how this occurs at a molecular level and discovered that the bacteria possess an “RNA thermometer,” which turns on expression of these virulence factors. At low temperatures, as found in water inhabited by the bacteria, a sequence from the bacterium's toxT messenger RNA (toxT encodes a protein that turns on virulence gene expression) folds into a structure that prevents its translation. However, at human body temperature, the structure opens up and the bacterium can express its virulence factor genes.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1411570111 (2014).

  8. Theoretical Biology

    Finding ways to reach the right endpoint

    1. Jelena Stajic

    Most complex systems have an element of randomness: Even if we can describe them exactly at one point in time, we don't know for certain where they will be next. Scientists use stochastic equations to compute the many possible trajectories these systems can take. If we constrain both end points of such trajectories, the usual approach of calculating all trajectories and rejecting those that do not end at the desired final point can be very inefficient. Zhao et al. introduced an approach in which they modified the probabilities for moving from one state to the next, so that the system was guaranteed to reach the set final state. The authors used examples from population genetics to illustrate the power of the method.

    J. Theor. Biol. 363, 419 (2014).

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