LEUCINE AMINOPEPTIDASE ACTIVITY IN ADULTS OF POMPHORHYNCHUS-LAEVIS (ACANTHOCEPHALA) - A HISTOCHEMICAL-STUDY

In frozen sections of the acanthocephalan Pomphorhynchus laevis, which is a frequent intestinal parasite of cyprinid and salmonid fishes. le ucine amino-peptidase (APase) was localized histochemically in outer p arts of the presomal bulbus as well as in all layers and most nuclei o f the metasomal body wall. Enzyme activity visualized at pH 6.5 using L-leucyl-4-methoxy-2-naphtylamide as the substrate was also associated with ovarian balls. immature larvae, and the testes. The results are discussed with respect to the possible function of APases and the prop osed sites of amino acid uptake in tissues of P. laevis.