Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 27. (Budapest, 1994)

DISCUSSION The presence of various biochemical substances in the forebody glands of C. complanatum indicated that these glands were basically involved in the synthesis of proteinaceous substances. Further histochemical studies for enzymes revealed that the substances present in these unicellular glands seem to be predominantly hydrolyzing enzymes as shown by the positive staining for acid and alkaline phosphatases, acetylcholinesterase and non-specific esterase. The glands in the metacercariae were full of endogenous content while in the adults some of the glands were empty, indicating that these glands become functional and start secretion as the metacercaria attains maturity. This is also evident from the relative degree of staining for various enzymes in metacercaria and adult. The more intense staining for acid phosphatase than alkaline phosphatase in glands of both metacercariae and adults of C. complanatum may be due to the fact that acid phospatase is generally more active than alkaline phosphatase in trematodes (Von Brand 1973, Probert and Lwin 1974, Siddiqui and Nizami 1982). The role of phosphatases in metabolism has been thoroughly discussed. They occur in regions where active transport of metabolites takes place and in tissues of the reproductive system (Von Brand 1973, Cesari 1974, Dennis et al. 1974). They are also involved in the uptake and transport of nutrients in vitellaria (Sharma 1976). Further, acid phosphatase has been implicated in the lysis of vesicle and synthesis of protein; alkaline phosphatase in the absorption of glucose and in permeation; non-specific esterase in the hydrolysis of synthetized protein and intracellular transport of the hydrolyzed proteins (Gupta and Sood 1974). Therefore, the presence of hydrolyzing enzymes such as acid phosphatase and non-specific esterase leads us to assume that the secretions of these glands may help in the synthesis and hydrolysis of proteins and in the intercellular transport of this hydrolyzed protein which may be utilized for body building and growth during the transformation of metacercaria to adult, while alkaline phosphatase may help in permeation as suggested by Gupta and Sood (1974). Such glands have also been reported from a number of trematode species (see references in Smyth and Halton 1983). In the forebody of strigeid trematodes, similar glands have been described and referred to as sub-cuticular cells/glands which have been reported to contain non-specific esterases (Öhman 1965, 1966, Bogitsh 1966). Furthermore Halton and Dermott (1967) reported the ultrastructure of certain gland cells in Haplometra cylindracea and Opisthiogfyphe ranae and suggested that the function of these glands is unclear and may be different in the two genera. In microphallids, the presence of unicellular glands in the forebody between the oral and ventral suckers was reported by Strong and Cable (1972) and Davies (1979). Numerous glands are present in the forebody of metacercariae and adults of Microphallus simUis. Histochemically, these glands have been reported to contain diastase-resistant neutral mucosubstances, RNA, protein, esterase and a small amount of acid phosphatase. Furthermore it has been suggested that acetylcholinesterase in the glands in M. similis may interfere with local peristalsis in the host gut, thus preventing parasite expulsion. The presence of an intense activity of acetylcholinesterase in C. complanatum