DAO 62:245-248 (2004)  -  doi:10.3354/dao062245

Effects of bile acids on proliferation and production of proteinase activity of Uronema marinum(Ciliophora: Scuticociliatida)

Hyoung Jun Kim1, Su Kyung Choi1, Seung Hyuk Choi1, Min Sun Kim1, Sung Koo Kim2, Yoon Kwon Nam3, Ki Hong Kim1,*

1Department of Aquatic Life Medicine, 2Faculty of Food Science and Biotechnology, and 3Department of Aquaculture, Pukyong National University, Pusan 608-737, South Korea
*Corresponding author. Email:

ABSTRACT: Little is known about the effects of bile acids in relation to infectivity on the biological characteristics of Uronema marinum, a serious opportunistic parasite of farmed olive flounder Paralichthys olivaceus. In this study, we examined the effects of bile acids on the proliferation of U. marinum and on proteinase production in vitro. Proliferation of U. marinum was significantly enhanced by lithocholic acid (LCA) at 30 and 60 µmol, and by chenodeoxycholic acid (CDCA) at 0.06 µmol. In contrast, a significant decrease in proliferation was observed with cholic acid (CA) at 30 and 60 µmol, and with deoxycholic acid (DCA) at all amounts used. Proteinase production from live U. marinum was significantly increased by LCA, whereas CA significantly decreased proteinase production. CDCA and DCA had no effect on proteinase production. Although the types and concentrations of bile acids in the faeces of olive flounder are not known, the present results suggest that bile acids in the culturing water might influence the proliferation and production of proteinases in U. marinum, resulting in an increased possibility of scuticociliatosis in olive flounder farms.

KEY WORDS: Uronema marinum · Bile acids · Proliferation · Proteases

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