Differences between short- and long-term cultures of Uronema marinum (Ciliophora: Scuticociliatida) in chemiluminescence inhibitory activity, antioxidative enzyme and protease activity

Differences between short-term (STC) and long-term (LTC) in vitro cultures of Uronema marinum in suppression of olive flounder (Paralichthys olivaceus) phagocytes' chemiluminescent (CL) response, antioxidative enzymes and protease activity were investigated. Luminol-enhanced CL was used to measure the production of reactive oxygen intermediates (ROIs) generated by respiratory burst of phagocytes using zymosan as a stimulant. Crude extracts of both STC and LTC of U. marinum inhibited CL responses of zymosan-stimulated phagocytes in a dose-dependent manner. The reduction of CL response was significantly higher in phagocytes exposed to extracts from STC as compared to those from LTC. Both crude extracts of U. marinum showed activities of superoxide dismutase (SOD) and catalase (CAT). Protease activity of the STC crude extract was significantly higher than that of the LTC extract. Results of this study suggest that antioxidative enzymes and proteases of U. marinum may participate in protection of the parasite against host phagocyte mediated oxidative damage. (C) 2003 Elsevier Science B.V. All rights reserved.