Studies on phospholipid turnover argue against sloughing of tegumental membranes in adult Schistosoma mansoni

• Published in: Parasitology 1999-09, Vol.119 (3), p.287-294
• Main Authors: BROUWERS, J. F. H. M., SKELLY, P. J., VAN GOLDE, L. M. G., TIELENS, A. G. M.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blotting, Western; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Cricetinae; deacylation/reacylation; Electrophoresis, Polyacrylamide Gel; Fatty Acids - analysis; Fatty Acids - physiology; Fundamental and applied biological sciences. Psychology; high performance liquid chromatography; Host parasite relation; pathogenicity; Host-Parasite Interactions; Invertebrates; lipid metabolism; Membrane Proteins - metabolism; Membrane Proteins - physiology; membrane sloughing; Nemathelminthia. Plathelmintha; Palmitic Acid - analysis; Palmitic Acid - metabolism; Phospholipids - metabolism; Phospholipids - physiology; Schistosoma mansoni - metabolism; Schistosoma mansoni - physiology; Schistosomiasis - parasitology; Scintillation Counting
• ISSN: 0031-1820; 1469-8161
• DOI: 10.1017/S0031182099004679

The tegumental membrane complex of Schistosoma mansoni is the site of interaction between the parasite and the host. The tegument is involved in uptake of many nutrients, but also plays a crucial role in the evasion of the actions of the host immune system. Essential for the success of this evasion is maintaining the integrity of the tegumental membranes. The rate of turnover of phospholipids was investigated by pulse-labelling worms cultured in vitro, followed by additional incubation in the presence of unlabelled substrates. Tegumental membranes were isolated, characterized using antibodies against specific tegumental proteins, and analysed. It was demonstrated that the most prominent fatty acid found in tegumental phospholipids, palmitate, incorporated rapidly into the phospholipid fraction during a 30 min pulse labelling. In a subsequent 20 h chase with unlabelled substrates, the incorporated radioactivity was lost again from the tegumental membrane complex. This high turnover of palmitate was found to be limited to phosphatidylcholine (PC) only. The turnover was due to deacylation/reacylation, and not to the sloughing of membranes as is the case in schistosomula. It is speculated that this rapid turnover of PC in the tegument of adult schistosomes plays a new and important role in the immune evasion by the parasite.