Off-campus Eastern Washington University users: To download EWU Only theses, please use the following link to log into our proxy server with your EWU NetID and password.

Non-EWU users: Please talk to your local librarian about requesting this thesis through Interlibrary loan.

Date of Award

Spring 2020

Rights

Access restricted for 1 year to EWU users with an active EWU NetID

Date Available to Non-EWU Users

2021-06-10

Document Type

Thesis: EWU Only

Department

Biology

Abstract

Amphibians worldwide are under threat from the infectious disease chytridiomycosis, which is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Bd is associated with the population declines of an estimated 501 species, 90 of which are presumed or confirmed extinct, making this the greatest documented loss of biodiversity attributed to a disease. Researching the amphibian skin microbiome may provide solutions to conservation of amphibians. Two main relationships have been observed between Bd and the microbiome: 1) bacteria producing antifungal metabolites can inhibit Bd and improve survival against the disease and 2) infection by Bd is believed to affect the composition of the skin microbiome. In collaboration with the Idaho Department of Fish of Game, Columbia spotted frogs (Rana luteiventris) from northern Idaho were swabbed to detect Bd and collect bacteria from the skin microbiome. Our study found Bd was prevalent in low infection intensities in 80% of 153 sites in the northern Idaho panhandle. Amplicon barcoded sequencing of the V4-V5 region of the 16S rRNA gene was performed to characterize the skin microbiome of frogs. Overall, the most abundant groups of bacteria on the skin were Burkholderiaceae, Pseudomonas spp., Stenotrophomonas spp., Sanguibacter inulinus, and Enterobacteriaceae. Results demonstrated skin microbiomes were distinct in infected and uninfected frogs, with key differences including greater relative abundance of Burkholderiaceae in infected frogs and greater relative abundance of Pseudomonas in uninfected frogs. Columbia spotted frogs and Pacific chorus frogs (Pseudacris regilla) were swabbed at Turnbull National Wildlife Refuge (TNWR) to measure Bd prevalence and infection intensity. Prevalence among Pacific chorus frogs (91.43%) was greater than prevalence among Columbia spotted frogs (67.74%), and infection intensities were also greater among Pacific chorus frogs compared to Columbia spotted frogs. Preliminary microbiome results showed a correlation between microbiome communities and infection intensity. Continued research on the amphibian skin microbiome could lead to the development of more effective probiotics as a conservation solution to population decline in amphibians.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Share

COinS