Senior Honors Projects, 2010-current

Date of Award

Spring 2015

Document Type

Dissertation/Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Biology

Advisor(s)

Reid Harris

Eria Rebollar

Abstract

The gram-negative bacteria, Janthinobacterium lividum (J.liv) is able to kill the pathogenic fungus known as Batrachochytrium dendrobatidis (Bd), which is known to be causing massive amphibian decline worldwide. The purpose of this research was to identify the ability of the probiotic bacteria, Janthinobacterium lividum (J.liv), to be horizontally transmitted from individual to individual and/or pseudo-environmentally transmitted from individual to environment and back to individual between Lithobates clamitans (green frog) tadpoles. Based on previous findings I hypothesized that pseudo-environmental and horizontal transmission will occur in tadpoles. This would be important for helping stop the decline of amphibians because it would provide a feasible way to spread this probiotic throughout environments worldwide. The experimental design had two treatments and their controls. The first treatment, which tested for pseudo-environmental and horizontal transmission, included two tadpoles in a container, swimming freely, with only one tadpole inoculated with rifampicin-resistant J.liv. The second treatment, which tested for pseudo-environmental transmission, included two tadpoles in a container, physically separated by a net, with only one tadpole inoculated with J.liv. There was no treatment testing for only horizontal transmission because there is no ways to have tadpoles interact with each other without sharing an environment. I also hypothesized that the treatment with horizontal and pseudo-environmental transmission would be more successful then the treatment with just pseudo-environmental transmission. Tadpoles were swabbed at different time points, and plated on rifampicin plates to determine the success of transmission. It was found that in both treatments, the tadpoles given the J.liv bath were able to retain J.liv on their skin immediately after inoculation but the pseudo-environmental treatment had overall better transmission of probiotic from one tadpole to another along with overall retention of J.liv on tadpoles skin. These results suggest that not all individuals have to be inoculated to apply the probiotic to the entire frog population, which has the potential to greatly facilitate disease mitigation efforts.

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