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UPTAKE, DISTRIBUTION, AND BIOCONVERSION OF FLUORESCENT LIPID ANALOGS IN THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS
Citation:
Chu, F., P. Soudant, Y. Huang, A. K. Volety, AND G. Constantin. UPTAKE, DISTRIBUTION, AND BIOCONVERSION OF FLUORESCENT LIPID ANALOGS IN THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS. Presented at 91st Annual Meeting of the National Shellfisheries Association, Halifax, Nova Scotia, April 18-22, 1999.
Description:
It has been established that host lipids play a unique role for long term survival and life cycle completion in endogenous parasites. Parasites exploit fatty acids and lipids from the host, not only for membrane synthesis, but also for modification of their surface integrity to avoid host defense. To study lipid utilization by this parasite, we followed the uptake of 'fluorescent-labeled' fatty acid and phospholipid analogs in the merozoite/meront and prezoosporangia stages of P. marinus. After 24 hr incubation at 28|C with fluorescent labeled phosphatidylethanolamine (PE), phosphatidylcholine (PC), and free fatty acid (FFA, C12:0) analogs, yellow-gold fluorescence was present primarily in the discrete lipid droplets throughout the parasite. Analysis of lipid class composition using thin layer chromatography showed that the merozoite/meront stage incorporated PC and transformed it into PE, FFA, triacylglycerol (TAG) and one component tentatively identified as phosphatidylserine (PS) and PE was also metabolized to PS, PC and TAG in meront/merozoite. Incorporation of PC and FFA (C12:0) was observed in prezoosporangia, but there was no conversion of PC to PE or PS, instead PC in prezoosporangia was metabolized into two components presumptively to be FFAs. The fluorescent-labeled C12:0 in prezoosporangia was incorporated in TAG. These results suggest that P. marinusincorporated and modified lipids from exogenous sources and that the metabolic modes of meront differed from prezoosporangia. The uptake and bioconversion of fluorescent lipid analogs in the parasite are currently being quantified.