DAO 52:119-122 (2002)  -  doi:10.3354/dao052119

Inhibition of chemiluminescent response of olive flounder Paralichthys olivaceus phagocytes by the scuticociliate parasite Uronema marinum

Se Ryun Kwon1, Chun Soo Kim1, Joon Ki Chung1, Hyung Ho Lee2, Ki Hong Kim1,*

1Department of Aquatic Life Medicine, and
2Faculty of Food Science and Biotechnology, Pukyong National University, Pusan 608-737, Korea
*Corresponding author. E-mail:

ABSTRACT: Experiments were conducted to evaluate the in vitro capacity of the scuticociliatian parasite Uronema marinum to inhibit chemiluminescence (CL) of olive flounder Paralichthys olivaceus phagocytes. Luminol-enhanced CL was used to measure the production of reactive oxygen intermediates (ROIs) generated by respiratory bursts of phagocytes using zymosan as a stimulant. Cytotoxic and antioxidative activities of excretory-secretory (ES) products of the parasite were evaluated as well. Live U. marinum and its ES products had a negative and dose-dependent effect on luminol-enhanced CL responses of zymosan-stimulated phagocytes of olive flounder. After CL assay, the number of phagocytes showing viability was significantly reduced in the cells incubated with live U. marinum at ratios of 2:1 and 1:1 phagocytes:ciliates or ES products with 0.3 mg protein ml-1 compared to controls. Lysis of phagocytes by exposure to ES products was observed also. ES products from U. marinum showed considerably high activities of superoxide dismutase (SOD) and catalase. The results of this study suggest that U. marinum can protect itself against host¹s phagocytes mediated oxidative damage by destroying phagocytes and scavenging ROIs.

KEY WORDS: Uronema marinum · Paralichthys olivaceus · Phagocytes · Chemiluminescence · Superoxide dismutase · Catalase

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