Dr. Murai Éva szerk.: Parasitologia Hungarica 16. (Budapest, 1983)

Lipase activity of Mesocestoides cor

ti The experimental design was partly identical with that for L. intestinalis, except that in addition to KRT maintenance medium Tyrode'

s and Hanks'

s solutions were also used for incubation. Similarly to L. intestinalis, the extract of tetrathyridium larvae of Mesocestoides corti split both the tributyrin and the N-methyl-indoxyl-myristate substrate, with activities of 1.1 jumol/ min/ml for tributyrin and rF = 64. 6% for N-methyl-indoxyl-myristate. Larvae incubated in a tributyrin-containing medium decomposed tributyrin, with an activity of 2. 1 5 umol/min/g worm. DISCUSSION Both the somatic extract of the liver fluke and the samples taken from the incubation media of worms hydrolysed tributyrin and triolein substrates. As compared to that of the somatic extract, lipase activity of the maintenance medium was very weak. Our observations allow us to presume that lipase functioning in the intestine similarly to proteases and amylase is released into the environment through the oral sucker of F. hepa tica. Presumably the function of lipase is to decompose the consumed lipids to molecules suitable for absorption, although no data are available on the role of lipids in the nutrition of flukes. As it has been proved by our observations, the liver fluke does not exert any effect on the host's pancreatic lipase. Enzyme-histochemical reactions have confirmed that lipase activity is localized primarily in the epithelial cells of the intestine, although the tegument also gives a positive reaction. Based on the decomposition of different substrates (tributyrin, triolein, N-methyl-indoxylmyristate), the somatic extract of L. intestinalis possesses a pronounced lipase activity. No lipase activity was demonstrated in samples taken from the medium of larvae. However, if plerocercoids were incubated with a substrate containing N-methyl-indoxyl-myristate, the presence of enzyme activity was proved by decomposition of the substrate. The results of fluorometric examination allow us to presume that the tapeworm species L. intestinalis and M. corti are capable of decomposing lipids present in their environment. This observation of ours is in contradiction with that of RUFF and READ (1973) who failed to demonstrate intrinsic lipase activity in Hymenolepis diminuta. According to our observations, the tapeworm species studied did not inhibit the activity of mammalian pancreatic lipase added to the maintenance medium constituting their environment. This finding is in contradiction with the inhibition observed by RUFF and READ (1973). MATSKÁSI, I. — HAJDÚ, É.: Élősködő laposférgek lipáz aktivitása A májmétely (Fasciola hepatica

) szomatikus kivonatából és fenntartó folyadékából egyaránt kimutatható lipáz aktivitás. Enzim-hisztokémiai reakcióval az aktivitást a bélhám sejtekben és a tegumentumban lehet lokalizálni. A galandférgek képesek a környezetük lipidjeinek bontására lipáz aktivitásuk révén. A vizsgált fajok nem gátolták a környezetükben lévő emlős hasnyálmirigy eredetű lipázt. Enzimhisztokémiai módszerrel a tegumentumban és a szubtegumentumban lokalizálható az aktivitás.