Dr. Murai Éva szerk.: Parasitologia Hungarica 12. (Budapest, 1979)
d) Effect of protease inhibitors on the proteolytic activity of liver fluke extracts This was examined to obtain more information on the nature of the liver fluke' s own proteases (Tables 5 and 6). II. Protease activity of the maintenance medium In the first experimental series the flukes were incubated in Tyrode solution for 4 hrs at 37°C. After removal of the flukes the BAEE and BTEE splitting activities of the medium were assessed as 0.278 and 1.071 U/ml, respectively. Table 10 Protease activity in bovine enzyme containing culture media of flukes with closed and open oral sucker after 4 hours incubation at 37°C BAEE-splitting activity U/ml x S n BTEE-splitting activity U/ml x S n without worms (control) 0.750* +0.224 7 2.970** to. 298 7 oral sucker closed 0. 535 +0.089 7 2.228 +0.335 7 oral sucker open 0.471 +0.138 7 2.042 + 0.356 7 The activity of bovine trypsin. The activity of bovine chymotrypsin^ In the second experiment the flukes were incubated under the same conditions as above, except that their oral sucker was sealed with Histoacryl tissue cement. At the end of incubation the maintenance medium showed BAEE and BTEE splitting activities of 0.0 50 and 0. 507 U/ml, respectively. Both enzyme activities differed significantly between the two groups (Table 7). III. Results of fluke-inhibitor studies a) Inhibitors released into the maintenance medium Samples of TC 135 incubation medium were examined for influence on bovine pancreatic trypsin and chymotrypsin. The results are shown in Table 8. The samples of medium depress the trypsin and chymotrypsin activity. b) Inactivation of host proteases in maintenance medium The test system employed in this series contained 2.4 ml 0. 15 M, Ca-containing TRIS-HC1 buffer (pH 7.8), 0.1ml incubation medium, 0,5 ml substrate. The results are shown in Table 9. It was established earlier that the flukes did themselves release proteases into the maintenance medium. As the applied methods did not make possible the differentiation in the
