The structure and function of the adhesive organ in strigeid trematodes

Abstract

The biology and life cycle of Apatemon gracilis minor is briefly described.The morphology of the cup–shaped forebody with the small lappets, the pear-shaped subcuticular cells and the very flexible finger–like adhesive organ lobes is considered in some detail.An extensive description of the body musculature is given and the mode of attachment of the parasite to the host mucosa is studied.The main results of the histochemical tests are: (a) a relative absence of enzymes in the adhesive organ and a greater activity in the lappets; (b) the presence of two types of esterase, a non-specific esterase of B-type in the caecal cells and a non-specific esterase of resistant type, possibly a non-specific cholinesterase, in the rest of the reacting sites in the parasite; (c) a relatively small activity for leucine aminopeptidase; (d) the presence of RNA at all sites of enzyme formation; and finally, (e), the presence of enzymes and carbohydrates in the cuticle.The activities of the parasite result in a local disruption of the host intestinal mucosa at the site of attachment. It is suggested that this is a result of the activities of the enzymes secreted by the parasite.The absorption of nutrients and the circulatory function of the excretory system are discussed.I should like to express my sincere thanks to Dr D. A. Erasmus for helpful discussions and advice during the progress of the work and to Professor J. Brough for giving me the opportunity to work in his department. The study was conducted during the tenure of a grant from Svenska Vetenskapliga Centralrådet i Finland.