Abstract – Dr. John Sorensen

Dr. John Sorensen, Department of Chemistry, University of Manitoba

Abstract

Natural products are small molecules produced as the result of secondary metabolism pathways in microorganisms such as fungi. Our research program is focused on examining in detail the biosynthesis of natural products produced by various fungal species. One major project involves screening for new natural products that are produced by soil fungi collected from Northern Manitoba. This bioprospecting is beginning to show some promise as a source of bioactive molecules and the structures of some of the natural products isolated to date will be presented.

Our other major research program involves examining the polyketide metabolites produced by species of lichen fungi native to Northern Manitoba. Lichens are a symbiotic association between a fungal and an algal partner. These slow growing organisms are a rich source of secondary metabolites, many of which have a demonstrated biological activity. Our main focus at present is the biosynthesis of usnic acid, produced by various species of Cladonia lichen. Usnic acid has shown activity against cancer cell lines and is used commercially as an antibiotic. Our goal is to characterize the enzymes responsible for each step in usnic acid biosynthesis using a molecular biology approach. Our efforts towards cloning the usinc acid polyketide synthase gene will be presented. Our preliminary results in the characterization of the oxidative enzyme will also be presented.