Lipids of Smittium Culisetae

Abstract

SUMMARY Neutral and polar lipids of Smittium culisetae were separated by silicic acid column and thin-layer chromatography. 76.3% of the total lipids was found to be neutral lipids and 23.7% was polar. Triglycerides were the most abundant (26.6%) of the lipids with lesser amounts of free fatty acids, steroids and diglycerides. The major phosphatide was phosphatidyl choline (17.8%) while phosphatidyl ethanolamine and phosphatidyl serine were present in smaller amounts. Gas chromatography of methyl esters of the fatty acids obtained from the individual lipid classes showed that the most abundant unsaturated fatty acid was palmitoleic (38.7%) and the predominant saturated fatty acid was palmitic (34.3%). The genus Smittium is included in the Harpellales of the Trichomycetes. The latter comprise a group of unusual fungi typically found in various arthropods as commensals in the digestive tract (Litchwardt, 1960). Species of Smittium like all other Harpellales are restricted to the guts of Diptera larvae where they complete their life cycle attached to the chitinous gut lining. Smittium culisetae Lichtwardt was first isolated by Lichtwardt (1964) from mosquito larvae. Smittium remains the only endozoic genus of the Trichomycetes cultured axenically and to our knowledge no information is available in the literature on the lipid composition of any of the species of Smittium. This report presents an examination of the lipid composition of Smittiumz culisetae. The individual lipid classes and phosphatides were separated and a quantitative determination was made. The total fatty acid content and the fatty acids in each class were determined.