【作者】 谭志军；

【导师】 周名江； 颜天；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生物学， 2006， 博士

【摘要】 本论文选择在我国分离得到的一株有毒赤潮甲藻-塔玛亚历山大藻(Alexandrium tamarense,ATHK株),研究了其对一种我国沿海常见和典型养殖鱼类鲈鱼(Lateolabrax japonicus)的危害机制。首先研究了塔玛亚历山大藻(ATHK)对鲈鱼鳃结构的影响及其溶血毒性;然后采用腹腔注射的方法,研究了高剂量塔玛亚历山大藻毒素(ATHK毒素:约为1.6×105细胞,相应PSP为0.886μg STX Equal,相当于每克湿重的鲈鱼PSP注射量为0.0118μg STX Equal)和低剂量塔玛亚历山大藻毒素(ATHK毒素:约为0.16×105细胞,相应PSP为0.0886μg STX Equal,相当于每克湿重的鲈鱼PSP注射量为0.00118μg STX Equal)在鲈鱼体内代谢过程中对鲈鱼肝脏、肾脏和鳃组织的超微结构、Na+K+-ATPase活性、肝脏功能和肾脏功能的影响、以及对抗氧化系统酶活性和异生物质代谢酶的影响,以期从不同方面了解塔玛亚历山大藻及其所产水溶性毒素(ATHK毒素)对鲈鱼的毒害效应及机制,为有毒赤潮的有效管理提供一定的科学依据。塔玛亚历山大藻(ATHK)对鲈鱼鳃组织影响的实验结果表明,该藻使鲈鱼鳃组织出现水肿现象,细胞间隙变大;粘液细胞颗粒不规则,颜色加深,颗粒发生凝集,有板结状;氯细胞线粒体内部基质凝集。不产PSP的一种亚历山大藻(AT-6)也使鲈鱼鳃出现水肿,且使细胞出现一定的固缩现象。显微镜观察发现鲈鱼鳃丝间存在有这两种亚历山大藻细胞。由此推测塔玛亚历山大藻ATHK和AT-6的表面结构可能具有能导致鲈鱼鳃组织水肿的机械作用。对人血细胞溶血实验结果表明塔玛亚历山大藻(ATHK)具有较强的溶血毒性,大小与藻的生长阶段和细胞密度都有一定的关系:指数期的溶血毒性最大,随细胞数目的增多,活性逐渐加大;藻细胞、细胞碎片、细胞内容物都有一定的溶血毒性,其中细胞碎片的活性最大。通过11种(株)产PSP的亚历山大藻、不产PSP的亚历山大藻以及标准PSP的实验结果表明这种溶血毒性是由藻细胞的其它非PSP物质造成的,且这种溶血毒性在产PSP的亚历山大藻中具有一定的普遍性。塔玛亚历山大藻(ATHK)对鲈鱼组织超微结构实验结果表明:ATHK毒素(约为1.6×105细胞,相应PSP为0.886μg STX Equal,相当于每克湿重的鲈鱼PSP注射量为0.0118μg STX Equal)能导致鲈鱼组织细胞超微结构发生剧烈的变化,更多还原

【Abstract】 The toxic effects of a PSP-producing strain of dinoflagellate Alexandrium tamarense(ATHK) on the perch Lateolabrax japonicus, a popular commercial fish in China, were studied in this thesis. The effects of the toxic algae on the ultrastructure of branchial cells of the perch after exposing to the cultures of A. tamarense(ATHK), and the hemolytic activity of A. tamarense(ATHK) on human erythrocytes, were studied at first. Then the extracted toxins prepared from A. tamarense (ATHK) cells were intraperitoneally injected into the perches in two different modes to study the impacts of toxins on the ultrastructure of different cells and enzyme activities of perches. The high dose injection was carried out only one time during the experiment, using extracted solution prepared from 1.6×105 algae cells with 0.05N acetic acid. The PSP toxicity was about 0.886μg STX Equal,and the dose injected was about 0.0118μg STX Equal/g fish (wet weight). The low dose injection was carried out multiply during the experiment, using the solution prepared from 0.16×105 cells,with the PSP toxicity about 0.0886μg STX Equal, and the dose injected was about 0.00118μg STX Equal/g fish (wet weight;) each time. The ultrastructure of liver, kidney and gill cells were observed, and the activities of the enzymes, including Na+K+-ATPase and xenobiotic-metabolizing enzymes and antioxidant enzymes, were tested to study the mechanism of the toxic effects of extracted toxins on L. japonicus.Experimental results showed that the gills of the juvenile perches exposed to the culture medium of A. tamarense(ATHK, 4 000cells/ml) for about 48 hours were significantly damaged. The most representative symptoms included tissue edema, irregular and congregated particles in mucus cells, and disintegrated mitochondria in the chloride cells. However, similar symptoms could also be observed in perches exposed to the culture medium of a non-PSP-producing strain of A. tamarense (AT-6 strain). The observation of algae cells in the gills of tested perches suggested that the mechanical injuries caused by the carapace of the algae, instead of PSP toxins, lead to the symptoms. In the hemolysis experiment using human erythrocytes, strong hemolytic activity of A. tamarense (ATHK) was found, and the hemolytic activity was更多还原