Comparison of toxic effects of nitric oxide and peroxynitrite on Uronema marinum (Ciliata: Scuticociliatida)

Diseases of Aquatic Organisms

Sung Koo Kim¹  Eun Hye Lee¹  Ki Hong Kim¹  Sung Mi Kim¹  Se Ryun Kwon¹  Yoon Kwon Nam¹ 

关键词: Uronema marinum;    Scuticociliatosis;    Nitric oxide;    Peroxynitrite;    Cytotoxicity;   

DOI  :  10.3354/dao058255

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: To discover the effects of nitric oxide (NO) and peroxynitrite on Uronema marinum (a ciliate responsible for systemic scuticociliatosis in cultured olive flounder Paralichthys olivaceus), the dose-dependent inhibitory effect of NOdonors, S-nitroso-N-acetylpenicillamine (SNAP) and 3 morpholinosydnonimine (SIN-1) on the proliferation and survival of U. marinum was investigated. The inhibitory effects of exogenous superoxide dismutase (SOD) and catalase on thetoxicity of SIN-1 were also investigated. After 24 h of incubation in the presence of 0.2 mM SNAP, the number of ciliates was not statistically different from that of the controls, whereas incubation in the presence of 0.5 mM SNAP reduced the number ofparasites significantly to 59.1% of controls. Concentrations of SNAP higher than 0.5 mM resulted in greater reductions in the number of ciliates, but levels of generated NO far exceeded physiological ranges. The number of viable ciliates incubated for 24h with 0.2 mM SIN-1 was reduced significantly to 25.0%, and all ciliates were killed by incubation in concentrations above 0.5 mM SIN-1. Although SOD decreased the toxic effect of SIN-1 on U. marinum, protection was not complete and did not improveafter increasing the SOD concentration from 50 to 400 U ml^-1. Addition of catalase ranging from 500 to 10000 U ml^-1 completely protected U. marinum from SIN-1 toxicity. Ciliates exposed to catalase alone or catalase plusSIN-1 showed significantly higher and dose-dependent proliferation rates compared to controls. Addition of haemoglobin, ranging from 0.5 to 2.0 mg ml^-1, also protected U. marinum from SIN-1 toxicity, and increased the proliferation ratedose-dependently. In conclusion, resistance of U. marinum to oxidative and nitrative stress may allow this pathogen to withstand the NO- and oxygen-radical-dependent killing mechanisms of phagocytic cells.

【 授权许可】

Unknown