9728284 Chu The protozoan parasite Perkinsus marinus (Dermo) is one of the two important parasites that have been causing severe mortality in the American (eastern) oyster, Crassostrea virginica, on the eastern and Gulf coasts of the United States since the 1950's. Presently, no information exists on lipid metabolism and biosynthesis in this parasite, although its host is an ecologically and economically important aquatic species. Using radiolabeled or "fluorescent-labeled" precursors, the investigator will characterize lipid metabolism and biosynthesis in this parasite in relation to its growth phases and life stages. She will also determine if temperature and salinity affect the parasite's lipid metabolism and biosynthesis and, in addition, will investigate the effect of P. marinus parasitism on the lipid metabolism of the host. She will use gas liquid chromatography (GLC), thin layer chromatography/flame ionization detector (TLC/FID) lipid analyzer (Iatroscan MK-3), high performance TLC, argentation TLC, and high pressure liquid chromatography (HPLC) equipped with a flow scintillation analyzer to analyze the uptake/incorporation, distribution, metabolism and synthesis of lipids, particularly phospholipids, and fatty acids in the parasite. The identification of fatty acids will be confirmed with an ELQ400-2 GC/MS system. The morphological distribution of "fluorescent labels" will be examined by epifluorescent and electron microscopy. Parasites are the major cause of disease in oysters on the eastern and Gulf coasts of the United States. These parasites derive their food, mainly in the form of lipids and protein, from the oyster. This is the first study of lipid metabolism of an internal parasite of an aquatic invertebrate species. The results from this research will contribute to the fundamental understanding of lipid metabolism in host-parasite relationships, especially in saltwater systems. The study will provide important information for the establishment of a host-parasite in vertebrate model to elucidate mechanisms involved in lipid acquisition in parasites. This information may also serve as the basis for the future development of a procedure to control oyster parasites.
