草鱼三元病原菌融合子的构建及生物学特性

Construction and its biological characteristics of tri-pathogenic bacteria syncretic fungus strains of grass carp(Ctenopharyngodon idellus)

采用细胞融合技术首次将肠型点状产气单胞菌菌株和鱼害粘球菌菌株融合,构建二元融合菌株AM-1,再将AM-1与荧光假单胞菌菌株融合,构建三元融合菌株AM-2。对AM-1和AM-2菌株的形态结构、生理生化特性、致病性、抗原性、抗体效价进行分析。结果表明,AM-1活菌椭圆形,无鞭毛,死菌短杆状,AM-2菌株短杆状,有鞭毛,它们的生理生化性状介于3原始亲本菌株之间;用AM-2菌株对当年健康草鱼种进行人工感染攻毒,被攻毒草鱼种具有烂鳃病、赤皮病及肠炎病的部分症状;AM-2菌株抗原的受免草鱼种对荧光假单胞菌、鱼害粘球菌和肠型点状产气单胞菌菌株的免疫保护率分别达64.90%、68.00%、67.00%,抗体效价最高达1∶256、1∶256、1∶512。测定了AM-1和AM-2菌株及亲本DNA含量并进行了琼脂糖凝胶电泳分析,AM-1和AM-2菌株DNA含量明显高于任一原始亲本。

In this experiment the bi-pathogenic bacteria syncretic fungus strains （AM-1） were firstly constructed by syndesis of Aeromonas punctata f. and Myxococcus piscicola of grass carp via cell amalgamation technique, then tri-pathogenic bacteria syncretic fungus strains （AM-2） were constructed by syndesis of AM-1 and Pseudomonas fluorescens according to same technique. After the configuration, physiological and biochemical characteristics, nosogenesis, antigen, effective value of antibody of AM-1 and AM-2 were analyzed , the results showed that the living AM-1 is elliptic , no-flagellum and the dead one is short-hanlm, while the AM-2 is short-hanlm with flagellum, and their physiological and biochemical characteristics are among three original parental fungus strains. The healthy grass carp seeds were infected by AM-2 and were examined to show partial symptoms of festered-bacterial gill-rot disease, red-skin disease and bacterial enteritis of grass carp. After grass carp is immunized by antigen of syncretic fungus strains, the protective ratio of immunity of grass carp against Pseudomonas fluorescens, Myxococcus piscicola, Aeromonas punctataf intestinalis are 64.9% ,68.0% and 67% respectively, and the rate of effective values of antibody are 1：256,1 ： 256, 1：512 respectively. After the DNA contents of AM-1, AM-2 and their parental fungus strains were analyzed by using gelose gelatin electrophoresis, the results showed that the DNA contents of syncretic fungus strains are significantly higher than that of their parental fungus strains.