The focus of this research is the investigation of fungicolous and mycoparasitic fungi that colonize sclerotia. Antifungal agents isolated from colonists of Aspergillus flavus are especially likely to exert effects on Aspergillus, an important opportunistic pathogen and mycotoxin producer. Studies of fungi that colonize Aspergillus sclerotia as sources of novel metabolites that inhibit the growth of the fungal host are thought to be unprecedented. With this renewal award, the Synthetic Organic Program is supporting the research of Dr. James B. Gloer of the Department of Chemistry at the University of Iowa. Dr. Gloer, in collaboration with Drs. Donald T. Wicklow and Patrick F. Dowd of the U.S. Department of Agriculture, will focus his work on investigating the fungal invasion of long-lived fungal bodies such as sclerotia and stromata. This process may frequently involve antibiosis and, therefore sclerotial colonists are potentially useful as a source of antifungal agents.