Meeting Abstract

8.1  Tuesday, Jan. 4  Dynamics of Antimicrobial Peptide Secretion in the Skin of Leopard Frogs PASK, J.D.*; ROLLINS-SMITH, L.A.; Vanderbilt University Medical Center, Nashville, TN james.d.pask@vanderbilt.edu

Amphibian populations including the northern leopard frog (Rana pipiens) have been declining for at least four decades, and overwhelming evidence now links a pathogenic chytrid fungus, Batrachochytrium dendrobatidis (Bd), to declines of amphibian populations in Australia, Central America, the western USA, Africa, and Europe. Because Bd colonizes the skin, antimicrobial peptides (AMPs) secreted onto the skin are thought to be an important component of the immune defense against Bd. To determine whether AMPs are critical for protection of leopard frogs against Bd, the presence and relative quantities of AMPs in the skin of resting frogs and norepinephrine-stimulated frogs were examined. Using MALDI-TOF MS and growth inhibition assays, my studies show that the levels of defensive AMPs on the skin of resting frogs are very low, increase following a natural activity such as movement to escape a predator, and once secreted, persist for at least two hours but decline rapidly thereafter. These studies support the hypothesis that AMPs are an important innate defense for this species against chytridiomycosis. Support: NSF IOS-0520847and IOS-0619536.