ANAEROBIC BACTERIA ISOLATED FROM THE GASTROINTESTINAL TRACTS OF BULLFROG TADPOLES (RANA CATESBEIANA)

The taxonomic identities and biochemical roles of symbiotic microbes living within the guts of amphibians remain very poorly studied to date. This is unfortunate because the normal microbiota has profound significance on the life history of larval amphibians. In this study, I investigated the bacterial flora of the gastrointestinal tracts of wild-caught Rana catesbeiana tadpoles under anaerobic conditions. I isolated several strains of bacteria and made attempts to identify them using a variety of culturing methods, biochemical tests, and differential staining techniques. Of the isolated cultures, I identified one as Edwardsiella tarda and another as a species of Clostridium. There is a paucity of information regarding the bacterial taxa in the guts of healthy larval anurans. I also determined the enzymatic activity of isolated strains for seven different carbohydrates, to elucidate the hydrolytic roles of these bacterial symbionts. Cellulose was the only carbohydrate tested that was not fermented by any isolated bacterial culture. The gastrointestinal microbiology of amphibians has major ecological, evolutionary, and environmental implications, and yet it remains mostly unexplored and warrants further study.