Schistosoma mansoni: ultrastructural studies on the esophageal secretory granules.

The posterior portion of the esophageal gland of Schistosoma mansoni produces a granule that is highly structured internally. Each granule consists of arrays of membrane-bound tubules enclosed by a membrane. Cytochemical tests indicate that the granules are not reactive for cytochrome c-oxidase but du react for macromolecular carbohydrates. It is believed that the granules are synthesized in the Golgi complex and are secreted at the base of the luminal amplifications of the esophagus. Colchicine treatment results in an accumulation of granules in the cyton region. Their physiological function is still undetermined, but it is hypothesized that they are involved with early stages of digestion of host red blood cells.