Isolation and partial structural characterization of new Kunitz-type trypsin inhibitors from the pike cestode Triaenophorus nodulosus

Surviving in the fish gut: Comparative inhibitory capacities against the host proteinases in cestodes of the genus Proteocephalus

“…The results of the present study are consistent with these data and confirm our earlier suggestions that a decrease in the intestinal proteolytic activity in a host fish infected with cestodes may occur due to inhibition of its enzymes by excretory-secretory products of the parasite, including serine proteinase inhibitors (Izvekova et al, 2017a(Izvekova et al, , 2017b. Triaenophorus nodulosus tapeworms from the intestines of pike, inhibitory capacity was related to the protein fraction with an apparent molecular weight of 14.4 kDa (Rogozhin et al, 2019). For the same cestode, it was shown that both the incubation medium and the worm homogenate inhibit the activity of commercial trypsin and proteolytic enzymes of the host intestines (Izvekova et al, 2017a).…”

“…Similarly, the presence of common protein bands with apparent molecular weights of 19–47 kDa in the incubation medium and the tapeworm extracts was shown for another cestode Caryophyllaeus laticeps from the bream intestine, along with the ability of these substances to inhibit the proteinase activity (Frolova et al., 2019). Meanwhile, in Triaenophorus nodulosus tapeworms from the intestines of pike, inhibitory capacity was related to the protein fraction with an apparent molecular weight of 14.4 kDa (Rogozhin et al., 2019). For the same cestode, it was shown that both the incubation medium and the worm homogenate inhibit the activity of commercial trypsin and proteolytic enzymes of the host intestines (Izvekova et al., 2017a).…”

“…Currently, the nature and performance of the inhibitory substances enabling the helminths to resist attacks of host proteolytic enzymes are still poorly understood, especially regarding the tapeworms inhabiting the fish gut. The worm homogenates and their incubation medium were found to inhibit host proteinases and commercial trypsin samples in such tapeworms as Triaenophorus nodulosus from the pike Esox lucius (Izvekova et al., 2017a; Rogozhin et al., 2019), Eubothrium rugosum from the burbot Lota lota (Izvekova et al., 2017b) and Caryophyllaeus laticeps from the bream Abramis brama (Frolova et al., 2019). However, it should be noted that these studies were performed only with disparate host–parasite pairs, making it difficult to compare the results and establish the presence and degree of interspecific variability in the inhibitory capacities of the worms.…”

Exploring Evolutionary Relationships within Neodermata Using Putative Orthologous Groups of Proteins, with Emphasis on Peptidases

“…Peptidases of the C01 family are used by trematodes to penetrate the host and migrate to specific organs, with the cathepsins B, F, and L among the most studied [ 21 , 27 , 68 ]. Similarly, the proteinase inhibitors perform important functions for the survival of the parasite in the host because they are responsible for inhibiting host enzymes or manipulating host immune responses [ 24 , 89 ]. Members of the also expanded I02 inhibitor family have anticoagulant and anti-inflammatory function [ 24 ] and include the Kunitz-type inhibitors that in cestodes suppress the proteolytic activity of their host [ 89 , 90 ].…”

Structure–Activity Relationship and Molecular Docking of a Kunitz-Like Trypsin Inhibitor, Kunitzin-AH, from the Skin Secretion of Amolops hainanensis

“…Kunitz-type trypsin inhibitors (K.T.I.s) are widespread in plants [ 1 , 2 , 3 ] and venoms [ 4 , 5 ], and the first Kunitz inhibitor was isolated from soybean in 1945 [ 6 ]. Since then, quantities of Kunitz-type inhibitors have been characterized from different species varying from plants to animals [ 7 ], and animal-derived K.T.I.s have obtained much focus in decades.…”