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Masters Theses

John Carroll University

Amphibians

Publication Year

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Chemotaxis Of Batrachochytrium Dendrobatidis Zoospores In Response To Live Amphibians, David Bartholow Jan 2018

Chemotaxis Of Batrachochytrium Dendrobatidis Zoospores In Response To Live Amphibians, David Bartholow

Masters Theses

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) …


Sequestered Alkaloid Defenses In The Dendrobatid Poison Frog Oophaga Pumilio Provide Variable Protection From Microbial Pathogens, Kyle Hovey Jul 2016

Sequestered Alkaloid Defenses In The Dendrobatid Poison Frog Oophaga Pumilio Provide Variable Protection From Microbial Pathogens, Kyle Hovey

Masters Theses

Amphibians produce the majority of their defensive chemicals, however alkaloid defenses in poison frogs are sequestered from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. However, alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in poison frog alkaloid defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect frogs. …