Dr. Murai Éva szerk.: Parasitologia Hungarica 13. (Budapest, 1980)

Table 8 Effect of L. intestinalis extracts on mammalian oC-amylase (U/g parasite) Plain extract Activity of extract+amylase OC- amylase X 1. 356 4. 511 2. 6 S

2 0. 145 0. 794 0.016 n 9 9 9 Amylase activity was assayed by the method of UJIHARA et al. (1965). Inactivated aliquots of extract were set up as controls. The mean amylase activity of fractions obtained by partial removal of the tegument was significantly greater than that of the extract prepared from the rest of parasite body, but no complete removal of the enzyme could be achieved by this approach (Table 9). Table 9 Amylolytic activities in the removed parts of the tegument and in the extract of remained parasite body Tegument Extract x 0. 750 0. 625 S

2 0. 026 0. 044 n 5 5 The enzyme assays were carried out with the method of UJIHARA et al. (1965) throughout. DISCUSSION THOMAS and TAYLOR (1968) and READ (1973) demonstrated earlier that certain cestode species interacted with environmental amylase. The amylolytic activity of amylase tended to increase in the presence of the parasites, but no intrinsic amylase activity was detected. The enzyme activity of cestodes could be removed by washing, as judged from the decrease of starch hydrolysis in the maintenance medium during the successive changes of the washing fluid (READ, 1973). Our own experiments on plerocercoid larval stages of Ligula intestinalis have substantiated the observation that the amylolytic activity of environmental oC-amylase tends to increase in the presence of live parasites. However, extracts prepared from homogenated plerocercoid larvae failed to stimulate the activity of the enzyme. On washing in several changes of saline or buffer solution, the greater part of the enzyme was detected in the washing fluids, but a minor residual activity persisted not only after the washes, but also after partial removal of the surface of the tegument. This suggested that an intrinsic amylolytic activity might exist in L. intestinalis. We were able to substantiate the tegumental adsorption of environmental amylase by L. intestinalis larvae. The quantitative relations of amylase