Using Gut Bacteria to Fight Diarrhea
Researchers have pinpointed the exact mix of microbes needed to rid mice of a hard-to-treat bacterial pathogen whose spores lead to chronic diarrhea. Antibiotics backfire because they kill the gut's normal microbial community, clearing the way for the pathogen, Clostridium difficile, to resettle. Physicians have restored normal gut microbiota by giving patients fecal material from a healthy person, but the treatment can introduce other undesirable pathogens. Microbiologist Trevor Lawley from the Wellcome Trust Sanger Institute in Hinxton, U.K., and colleagues developed a similar treatment that cured mice. Then they cultured bacteria from the fecal material used in the cure, trying to narrow down the number of potential bacteria responsible. Researchers tried different combinations of the 18 types of bacteria they isolated. Only one particular mix of six bacteria cured the mice, the team reports this week in PLoS Pathogens. Now, the researchers are culturing the human fecal material used to eradicate this infection in people. If they succeed, someday “a simple suppository of the bacteria could prevent C. difficile reinfection and obviate the need for antibiotics, which may exacerbate the problem,” says Brendan Wren, a microbiologist at the London School of Hygiene & Tropical Medicine who was not involved with the mouse study. http://scim.ag/GutBacteria
Butterfly Mystery Solved
Monarchs aren't the only continent-hopping butterflies. A new study finds that painted ladies (Vanessa cardui), common in Europe and the United Kingdom, are also long-distance commuters, traveling back and forth to North Africa. Although the insect's northward trip to Britain has been well-documented by citizen scientists, few saw them heading south again across the English Channel—suggesting the commute might be one-way. But in the spring of 2009, millions of painted ladies hit the shores of the United Kingdom, enabling researchers to correlate some 60,000 sightings with data from radars monitoring insect movements above 150 meters.
The radar revealed a high-altitude southward migration route: Most painted ladies ascended to 500 meters or so to hitch rides on fast-moving winds, ecologists reported last week in Ecography.
The southbound insects—offspring of the northward-traveling migrants—left for North Africa in two waves, one in August and one in October, sometimes traveling more than 50 kilometers an hour—twice as fast as they can fly on their own, the researchers say. Radar sightings suggest that in 2009 11 million painted ladies landed in the United Kingdom and 26 million left—evidence that, far from being a dead end, the British Isles gave the species a boost. http://scim.ag/PaintedLady