Date of Award
Master of Science (MS)
Dr. Christopher Sheil
Batrachochytrium dendrobatidis (Bd) is one of the primary drivers of amphibian decline, and has spread rapidly on a global scale, but the mechanisms of Bd movement on small spatial scales are poorly understood and may play a role in transmission and infection. The flagellated zoospores of this fungus exhibit chemotaxis in response to single chemical cues, towards potential nutrient sources and away from metabolites of anti-fungal bacteria (AFB) present on amphibian skin. Levels of cutaneous AFB were manipulated on Eurycea bislineata hosts (either by bathing in a culture of the AFB Janthinobacterium lividum, or bathing in antibiotics) to test the effects of differences in cutaneous microbiota on the chemotaxis of Bd zoospores. Chemotaxis was measured using a hemocytometer grid to track average movement of zoospores for 45 minutes. A stochastic model was implemented based on observed magnitudes of chemotaxis to estimate probability of zoospores reaching a host as a function of distance from host. Differences in net chemotaxis between treatments was non-significant, and overall levels of mean net chemotaxis were low with high variance. The model suggests that chemotaxis is not a strong driver of probability of Bd zoospores reaching a host relative to simple distance from the host. Results do not support chemotaxis as a strong driver of Bd transmission, but chemotaxis may play a role in the development of Bd infections.
Bartholow, David, "CHEMOTAXIS OF BATRACHOCHYTRIUM DENDROBATIDIS ZOOSPORES IN RESPONSE TO LIVE AMPHIBIANS" (2018). Masters Theses. 35.
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