Testing Geomyces pannorum for enzymes that could play a role in the ecology and pathogenesis of White‐nose Syndrome agent G. destructans

Toyota Auditorium, Howard H. Baker Jr. Center for Public Policy

White-nose Syndrome, an emerging disease of hibernating bats, has killed over 5.5 million bats in the northeastern United States and Canada. Its rapid spread across the country, beginning in New York in 2006 and currently reaching as far south as Alabama, has led to numerous cave closures and potentially dramatic agricultural costs. The fungus Geomyces destructans, first isolated from infected bats, was recently shown to be the etiological agent of the disease. Understanding the natural history of G. destructans, particularly its ecology in bat hibernacula, is crucial for disease management. Geomyces, the anamorph of Pseudogymnoascus (Leotiomycetes), consists of 11 saprotrophic species known predominately from cold soils. The best understood species, G. pannorum, causes an opportunistic skin infection in immunocompromised patients. Using G. pannorum as a model organism, we tested for several enzymes that could play a role in the ecology of G. destructans. Already known for its keratinase and chitinase production, G. pannorum also tested positive for β-hemolysis. Assays using three cellulose sources found that G. pannorum was weakly positive for β-glucosidase, but negative for endoglucanase and cellobiohydrolase activity. We also determined that G. pannorum produces iron-scavenging siderophores that permit growth in iron-poor environments and can be key components of pathogenesis. These enzymes, if also present in G. destructans, may be important components in host infection and proliferation in the environment. Future research will investigate G. destructans enzyme activity and growth in diverse cave sediments.