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

out as described by Kalantan and Arfin (1988). Adults of C. complanatum were obtained from the oesophagus of an experimentally infected chick (Gallus gallus domesticus) following the method of Kalantan et al. (1991). Excysted metacercaria as well as adult worms recovered from the chick 4 days post-infection were fixed in acetic acid-formol- alcohol (AFA); 10% buffered formalin; Bouin's fluid; 70% ethanol and formol calcium at 4 °C. Paraffin and/or frozen sections were cut and stained. Various histochemical tests employed for the detection of different moieties were adopted from Pearse (1968) and from Bancroft and Stevens (1982) unless otherwise stated (see Table 1). The following enzymes were investigated histochemically with appropriate controls and inhibitors: acid phosphatase (EC 3.1.3.2) by the ^-glycerophosphate lead method; alkaline phosphatase (EC 3.1.3.1) by the ^-glycerophosphate calcium salt method; acetylcholinesterase (3.1.1.7) by the acetylthiocholine iodide method and non-specific esterase (3.1.1.1) by the indoxyl acetate method. In conjunction with these, some sections were pre-incubated in phosphate buffered solutions of 10"

2 M Ag NO3/IO"

4 M Esterine at 37 °C for 1 h to be used as controls. Other controls consisted of sections of the worm heat-inactivated at 90 °C for 5 min prior to incubation in substrate or omission of the specific substrate from the incubation medium (Table 1). RESULTS While studying the general histochemistry of metacercariae and adults of C. complanatum, certain glands were observed in the forebody of the worms, particularly in the region of oral and ventral suckers (Figs 1-6). The number of glands was found to be increased during the transformation of metacercaria into adult. The glands were unicellular, measured 12-24x 12-16yum (mean = \9x\3.6pm) and showed affinity to various stains. Various biochemical substances localized in gland cells are summarized in Table 1. The gland cells reacted positively for basic proteins, elastin, keratin-like proteins, fibrin, tyrosine, dityrosine, acid mucopolysaccharides and nucleic acids (Figs 1-4). Glycogen was also present as the intensity of PAS reaction was decreased on diastase treatment. Collagen was found to be absent from the gland cells of both metacercariae and adult worms. The results of histochemical tests and controls for enzymes indicated activities of acid and alkaline phosphatases, acetylcholinesterase and non-specific esterase in forebody glands of both metacercariae and adults of C. complanatum (Figs 5-6). However, the intensity of these biochemical components was not the same in metacercariae and adults. The intensity of various proteins (basic proteins, elastin, fibrin, proteins having S-containing amino acids) was higher in metacercariae than in adults. While in enzyme localization a major difference was observed between the metacercarial and the adult stage in that the glands in the metacercaria were full of endogenous content while in adult some of the glands were empty as if they had discharged their contents. However, in adults the glands other than empty ones showed a positive reaction for these hydrolyzing enzymes (Fig. 6).