Possums and sodium fluoroacetate resistance
Possums, from populations with exposure to this vegetation, are particularly tolerant to fluoroacetate. However, the level of tolerance varies among the different populations of each species, depending on the degree to which the toxic plants were present in their microhabitat. The brush-tailed possum (T. vulpecula) from Western Australia was found to be nearly 150 times more resistant to fluoroacetate intoxication in vivo than the same species from South Australia. Both possums are capable of de-fluorinating fluoroacetate at similar rates by a glutathione-dependent enzymic mechanism resulting in the formation of free fluoride ion and S-carboxymethylcysteine. Glutathione was also capable of partial protection against the toxic effects of fluoroacetate in vitro by a further unelucidated mechanism.
This tolerance appears to be an adaptation to the presence of monofluoroacetic acid in many species of the plant genera Gastrolobium and Oxylobium, which occur within the range of these mammals in Western Australia.
This change is an example of a chemical change as they have adapted to a chemical that was present in their environment.
|Sodium fluoroacetate |
http://www.doc.govt.nz/upload/documents/science-and-technical/sfc001.pdf http://www.publish.csiro.au/?act=view_file&file_id=BI9790015.pdf http://www.feral.org.au/foods-of-the-australian-brush-tailed-opossum-trichosurus-vulpecula-in-an-exotic-forest/...