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fairy_toadmother

pesticides and CA redlegged frog

fairy_toadmother
16 years ago

some intersting info and suggestions about pesticide usage...click the link. it is pdf and you will need to enlarge to read it.

also, this is copied from frogwatch newletter that goes to my email. probiotics and frogs...published in Herp Digest.

3) Probiotics Could Save Frogs - Bacterial Baths Help Amphibians FightOff Fungus. Helen Pearson, Newsnature.com, 3/7/2007 The Mountain yellow-legged frog of California is plagued by fungalinfections.NHPA Planting bacteria on frogs' skin might help to save amphibians fromtheir global decline, hints new research. The work shows that frogprobiotics can help to fight off a lethal fungus. Many populations of amphibians are plummeting, and some have alreadygone extinct. One of the major causes is a fungus calledBatrachochytrium dendrobatidis, which lives on the skin of some frogsand salamanders. As in humans, amphibians host a community of bacteria on their skin. SoReid Harris at James Madison University in Harrisonburg, Virginia,wondered whether the community carried by amphibians susceptible to B.dendrobatidis had lost its ability to fight off the fungus. To test this idea, Harris and his colleagues isolated differentbacteria species from the skin of a common salamander. They put the eachof these species on top of some B. dendrobatidis growing in a Petri dishand found that several of them killed off a patch of the fungus1. Now they have shown that at least one of these bacterial species ùPedobacter cryoconitis ù can help amphibians to survive. The teamallowed red-backed salamanders to swim in a bath of this bacteria fortwo hours, and then infected them with the lethal fungus. When tested 18 days later, the salamanders given the bacterial bathwere nearly 30% more likely to have rid themselves of the fungalinfection than were the untreated animals. Harris speculates that thebacterium is probably making a natural antibiotic. He reported hisresults at a meeting on microbes and conservation at the American Museumof Natural History in New York on 26 April. Another bacterium, called Pseudomonas reactans, actually made thesalamanders more susceptible to the fungus, perhaps because it displacedregular, infection-fighting bacteria from the skin. Harris suggests that environmental stresses such as climate change orpollution might change an amphibian's community of skin bacteria. Thestressed animals might make less skin mucus, on which the bacteria feed,or they may make more stress hormones, which would encourage differentbacterial species. Exposing threatened amphibians to the fungus-fighting bacteria, perhapsby adding it to ponds or sites that they frequent, might help to reversesome of the population decline, Harris suggests. With few other optionsavailable, this strategy is worth pursuing, he says: "It's the onlything that's offered a glimmer of hope". "I think it's a very promising area that needs to be pursued," saysLouise Rollins-Smith, who studies amphibian immunology at VanderbiltUniversity in Nashville, Tennessee. "It's such an important conservationproblem. Any information on a mechanism that could protect them isvaluable." Because it is unclear how long the effect of the bacteria will last,the microbes might have to be introduced again and again. The idea is akin to the probiotic food and drinks that some peopleswallow to try and change the community of microbes living in theirguts. Some researchers are also toying with the idea of developingprobiotics for human skin. Probiotics have also been used in aquaculture- in fish food or simply in the water - to try and increase yields. Harris now plans to collaborate with colleagues in California to testwhether the probiotic protects the Mountain yellow-legged frog (Ranamuscosa), an endangered species that usually succumbs to the fungus. References 1. Harris R. N., James T. Y., Lauer A., Simon M. A. & PatelA. . EcoHealth, 3 . 53 - 56 (2006).

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