Schistosoma mansoni: Pattern of release of secretory products

Abstract

Adult Schistosoma mansoni were maintained in vitro for 1 hr with radioactively labeled precursors of protein, glycoprotein, and polysaccharides. The worms were then washed extensively and the supernates analyzed. The precursors N-acetylglucosamine, N-acetylgalactosamine, glucosamine, galactosamine, glucose, leucine, and fucose were incorporated into the worms and both large and small molecular weight products accumulated in the supernatant. For all the precursors except fucose, there was an initial rapid and then slower phase of release for both the large and small molecular weight materials. The amount of label retained by the worms as well as the proportion excreted as large molecular weight material was characteristic for the precursor used. In contrast, the products of fucose were released within 4 to 6 hr and therefore only exhibited the early secretory phase. There was no retention of fucose by the worms. Hydrolysis of large molecular weight products revealed that the N-acetylglucosamine-derived material was incorporated as amino sugars and fucose was incorporated as fucose. Therefore, N-acetylglucosamine and fucose precursors can specifically label secretory glycoproteins of schistosomes in a manner similar to that in mammalian systems.