Proteolytic equipment of the blood-feeding monogenean Eudiplozoon nipponicum
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| Year of publication | 2016 |
| Type | Conference abstract |
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| Description | Members of the family Diplozoidae are blood-feeding monogeneans mainly parasitizing on the gills of cyprinid fishes. They may have pathogenic effects on their hosts caused by mechanical damage of gill filaments accompanied by secondary infections, or by induction of hypochromic mycrocytic anemia. The information about blood processing mechanisms in monogeneans of the subclass Heteronchoinea (Polyopisthocotylea) stems from ultrastructural or histochemical analyses. It has been assumed that digestion is intracellular and takes place in a specialized type of gut cells. Only little information exists about the biochemistry of digestion. Therefore we focused on biochemical and molecular characterization of peptidases which can be involved in digestion of blood proteins. The presence of the cysteine class of peptidases, mainly cathepsin L, was approved in samples of excretory/secretory products and in soluble protein extracts from adult Paradiplozoon bliccae and Eudiplozoon nipponicum by using fluorogenic substrates, specific inhibitors and a biotinylated/fluorochrome-labelled affinity probe DCG-04. In the gels after electrophoresis or on blots we observed labelled bands of 35 kDa in the case of both species and 24 kDa for E. nipponicum only. Soluble protein extracts of worms were separated by 2D electrophoresis; detected spots around 35 kDa for P. bliccae and around 35-25 kDa for E. nipponicum were identified by mass spectrometry analyses as cathepsins L. On the basis of transcriptome analyses we have predicted 30 peptidase genes in E. nipponicum, 9 of which may be involved in nutrient digestion. Cathepsin L and cathepsin B of E. nipponicum have been expressed in Pichia pastoris yeast and are being biochemically characterized. |
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