Findings

Science  10 May 2013:
Vol. 340, Issue 6133, pp. 666
  1. More Clues to Origins of Frog-Killing Fungus

    Fatal fungus.

    The genome of a frog killer reveals its complicated nature.

    CREDIT: FORREST BREM

    Infections by the chytrid fungus Batrachochytrium dendrobatidis (Bd) have devastated amphibian populations around the world, causing the decline or extinction of 200 species. By sequencing the genomes of 29 Bd strains, Erica Bree Rosenblum from the University of California, Berkeley, and her colleagues discovered that many of the strains had arisen well before the epidemic started and differ significantly, they reported this week in the Proceedings of the National Academy of Sciences. "We've been treating this pathogen as one singular thing, but it has different subgroups with different properties," Rosenblum says. Unfortunately, that will complicate efforts to pin down where, when, and how the killer fungus arose.

    A second study, published this week in PLOS ONE, adds weight to a prevailing theory that humans helped to spread the fungus by importing and releasing the African clawed frog, used 60 years ago for human pregnancy testing. San Francisco State University ecologist Vance Vredenburg and his colleagues found Bd in clawed frog museum specimens from California and Africa, suggesting that imported infected frogs carried the fungus from Africa to California, where it spread to other species.

  2. Slow Malaria: Infect Mosquitoes

    Infecting a mosquito with a bacterium may not seem like a big scientific feat—but it is if the infection might just stop the insect from transmitting malaria.

    A study by Xi Zhiyong of the Michigan State University in East Lansing, published on page 748 of this issue, shows that it's possible to infect Anopheles stephensi, the main insect carrier of the malaria parasite in South Asia and the Middle East, with Wolbachia, a bacterium that employs shrewd genetic tricks to spread rapidly through insect populations. Motivated by studies showing that mosquitoes harboring the bacteria spread pathogens less efficiently, researchers had tried in vain for more than a decade to establish a Wolbachia infection in Anopheles.

    Field studies with Wolbachia-infected Aedes aegypti mosquitoes, which can transmit dengue, have taken place in Australia (Science, 10 December 2010, p. 1460) and are under way in Vietnam, led by Scott O'Neill of Monash University in Australia. "I'm very jealous" of Xi's team, O'Neill says. Xi says field studies in India are the next step; so is trying to infect A. gambiae, the most important malaria vector in Africa, with Wolbachia. http://scim.ag/mosqbact

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