Adsorption and inactivation of proteolytic enzymes by Triaenophorus nodulosus (Cestoda)

Abstract

SummaryThe proteolytic activity in washings off the Triaenophorus nodulosus cestode tegument and the ability of the worms to inactivate proteolytic enzymes were studied. It was found that the major proteolytic activity in the washing samples is represented by the easily desorbed fraction most probably characterizing the activity of the host's enzymes. Serine proteinases are an essential part of these enzymes. It was shown that the worms' incubation medium and their homogenates can inhibit host proteinases and commercial trypsin samples. Suppressive activity of the incubation medium suggests that the inhibitors are rather spontaneously produced by the worms than induced by the presence of proteinases in the surrounding medium. The inhibitor produced by the cestode is hypothesized to be trypsin-specifi c.

Influence ofTriaenophorus nodulosusplerocercoids (Cestoda: Pseudophyllidea) on the occurrence of intestinal helminths in the perch (Perca fluviatilis)

“…While extensive pathologies have been reported within the livers of fish harbouring this parasite (Kuperman, 1981; Hoffman et al , 1986; Brinker & Hamers, 2007), no morphological effect on the intestine has been documented, although it is not known if these studies paid any particular attention to this organ. Only changes to the activity of intestinal enzymes in these infected fish have been reported so far (Izvekova & Izvekov, 2013). Therefore pathological changes to the intestine of perch as a result of T. nodulosus E/S products are likely and in vitro studies on other fish cestodes indicate that these products will provoke host cellular immune responses (Morley & Hoole, 1997; Scharsack et al , 2013).…”

“…Therefore pathological changes to the intestine of perch as a result of T. nodulosus E/S products are likely and in vitro studies on other fish cestodes indicate that these products will provoke host cellular immune responses (Morley & Hoole, 1997; Scharsack et al , 2013). When combined with known T. nodulosus effects on the activity of host digestive enzymes (Izvekova & Izvekov, 2013), a profound alteration in the suitability of the fish intestine as an environment for the establishment and growth of other helminths is to be expected.…”

“…Other important activation factors include the morphological structure and microstructure of the intestinal tract, as well as mechanical pressure, intestinal microbial communities and the role of food movement (Macko, 1980). Within T. nodulosus -infected perch, changing levels of intestinal enzymes (Izvekova & Izvekov, 2013), together with other altered physiochemical and morphological parameters, will change the intestinal environment and influence the conditions necessary to trigger activation of ingested stages of helminths. Such intestinal changes, as found with mammals (Lagapa et al , 2008), are likely to vary with the intensity and level of development of T. nodulosus plerocercoids in the liver of perch, and thus the strength and range of physiochemical signals necessary to trigger parasite activation will narrow, depending on the sensitivity of the parasite species.…”

“…Furthermore, a decrease in glycogen content and glucose levels in the liver, also associated with an increase in wet weight, influences carbohydrate metabolism (Izvekova, 2001). Such extensive changes to the liver, in turn, can result in a substantial impact on the physiology of the intestine with, in particular, the activity of digestive enzymes being reduced (Izvekova & Izvekov, 2013). These enzymes have an important role in the establishment, development and site selection of many intestinal helminths (Lackie, 1975; Cheng, 1976; Macko, 1980).…”

Localization of the proteinase inhibitor activity in the fish cestode Eubothrium rugosum

“…In a previous study, we found no significant inhibitory effect of E. rugosum incubation medium on trypsin activity (Izvekova et al, 2017a). However, since the incubation medium of another cestode, Triaenophorus nodulosus, living in the pike intestine was found to inhibit trypsin samples (Izvekova et al, 2017b), we have changed the experimental design to search for a similar capacity in E. rugosum. Thus, in the previous experiment, the worms were incubated in 5 ml of Ringer's solution, and now, the solution volume was reduced to 2.5 ml to minimize dilution and enhance a possible inhibitory effect.…”