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2013 Abstracts

Toxin-Degrading Bacteria: Herbivorous Rodents May Provide a Source of Novel Microbes for Agricultural Herbivores

Ashley Stengel, University of Utah


Agricultural herbivores, such as cattle, often encounter plants containing toxins. One class of toxins, tannins, bind to proteins and inhibit digestive enzymes from acting to liberate nutrients. In this way, tannins prevent optimal absorption of nutrients. To overcome this challenge, some herbivores host bacteria with the ability to degrade tannins. Currently, there is a push to find novel microbes capable of aiding animals in detoxifying these compounds. Therefore, we aimed to isolate tannin-degrading bacteria from the desert woodrat (Neotoma lepida), a wild, herbivorous rodent that feeds largely on a tannin-rich shrub, creosote bush (Larrea tridentata). Woodrat feces were cultured on tannin-treated media, and bacteria capable of degrading tannins were further characterized with DNA sequencing. Results revealed that from 9 isolates, three species of tannin-degrading bacteria were present: Enterococcus faecalis, Bacillus subtilis, and Escherichia coli. Further characterization was performed through measurement of tannase activity. The activity of each isolate varied significantly between bacterial species as well as within a species. Ultimately, I hypothesize that these tannin-degrading bacteria facilitate the ingestion of tannin-rich plants by woodrats. Additionally, this research exemplifies how wild herbivores, such as the desert woodrat, provide an essential source of tannin-degrading microbes that could be introduced into domestic herbivores in order to improve agricultural practices.