Enzyme system responsible for the generation of superoxide anion in red tide plankton, Chattonella marina

Chattonella marina是一种针形藻类，是赤潮中毒性最强的浮游植物之一，对鱼类尤其是黄尾五斑海鲫具有很高的毒性。虽然查顿氏菌毒性作用的确切机制尚不清楚，但已证明动脉血氧分压的降低是鱼类暴露于查顿氏菌后观察到的最早的生理紊乱。码头鱼类暴露于C.玛丽娜还建议，过多的粘液导致呼吸水流通过鳃膜的阻塞，干扰O2的传递，导致窒息。C.已知marina在正常生理条件下产生活性氧物质（ROS），例如超氧阴离子（O2-）、过氧化氢（H2 O2）和羟基自由基（-OH）。虽然有证据表明活性氧与暴露于C. marina，探讨了C.码头仍有待澄清。在本研究中，我们发现C. marina细胞显示出依赖于NAD（P）H的O2-产生;这种反应可被哺乳动物NADPH氧化酶的特异性抑制剂二苯碘铵（DPI）抑制。当C.使用抗人嗜中性粒细胞细胞色素b558大亚基（91 kDa）的抗体通过免疫印迹分析marina，检测到约110 kDa的主带。此外，在C.用间接免疫荧光法测定。这些结果为嗜中性粒细胞NADPH氧化酶类似酶系统参与C.码头

Chattonella marina, a raphidophycean flagellate, is one of the most noxious red tide phytoplankton and is highly toxic to fish, especially to yellowtail Seriola quinqueradiata. Although the precise mechanism of the toxic action of Chattonella sp. remains unclear, it has been demonstrated that a decrease in oxygen partial pressure of arterial blood is the earliest physiological disturbance observed in fish after exposure" to C. marina. Physiological and histological studies of fish exposed to C.\marina also'suggested that;the blockade of respiratory water flow through the gill lamellae caused by excessive mucusiinterferes with O2 transfer, resulting in asphyxia. C. marina is known to produce reactive oxygen species (ROS) such as superoxide anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (-OH) under normal physiological conditions. Although several lines of evidence suggest that ROS are involved in the mortality of fish exposed to C. marina, the mechanism; of ROS generation in C. marina is remained to be clarified. In this study, we found that the cell-free supernatant prepared from C. marina cells showed NAD(P)H-dependent O2- generation; and this response was inhibited by diphenyleneiodonium (DPI), a specific inhibitor of mammalian NADPH oxidase. When the cell-free supernatant of C. marina was analyzed by immunoblotting using antibody raised against the human neutrophil cytochrome b558 large subunit (91 kDa), a main band with approximately 110 kDa was detected. Furthermore, the cell surface localization of the epitope recognized with this antibody was demonstrated in C. marina by indirect immunofluorescence. These results provide evidence for the involvement of enzymatic system analogous to the neutrophil NADPH oxidase as a source of O2- production in C. marina.