Analysis of total and surface membrane lipids of Schistosoma mansoni

Lipids extracted from whole worm homogenates and tegumental outer membranes of guinea pig-derived 5-day, 2-, 3- and 6-week old schistosomes have been analysed by thin layer chromatography. Six-week hamster-derived parasites have been studied for comparative purposes. All homogenates contained neutral lipids, cholesterol and several phospholipids; phosphatidyl choline and phosphatidyl ethanolamine were major components. Phospholipid (P3) was absent from homogenates of 5-day worms but was present in older parasites. A single phospholipid (P4) which co-chromatographed with phosphatidyl glycerol was unique to hamster-derived parasites. One glycolipid (G1) was ubiquitous to all homogenates and co-chromatographed with the monogalactosyl ceramide marker. A second sugar-containing lipid (G2) was unique to 3-week worm homogenates, and was highly polar. It was resolved beneath the trigalactosyl ceramide marker. Tegumental membranes isolated from 6-week adults contained at least five glycolipids, four of which were also highly polar. Cholesterol and two dominant phospholipids occurred in the membranes of 2-, 3-, and 6-week worms. One phospholipid co-chromatographed with phosphatidyl choline; the other had an Rf value (relative band speed) equivalent to phosphatidyl ethanolamine. Membranes from liver stage parasites contained a further phospholipid which cochromatographed with sphingomyelin, and three additional, phosphate-staining lipids (P1, P3 and P6). Five sugar-containing lipids occurred in adult membranes only; four were highly polar, being resolved near the origin. Similar components were identified in extracts of host erythrocytes. The remaining membrane lipid appeared homologous to G1 identified in the whole worm homogenates. Important changes in lipid composition thus occur during schistosome growth and maturation in guinea pigs; moreover, worms derived from different rodents express different lipids.