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养殖的三疣梭子蟹(Portunus trituberculatus)秋、冬季常发生非典型症状的死亡.本研究取濒死的三疣梭子蟹内脏及体腔液进行细菌分离,经纯化传代获得1株优势菌HY.HY菌的革兰氏染色呈阴性,菌体呈杆状、弧形或逗点状,无荚膜,无芽孢,极生单鞭毛,运动性强.生长特性和生化试验表明该菌生长需盐,最适生长的NaCl含量为30 mg/cm3;28℃下生长旺盛,能利用葡萄糖产酸但不产气,可以利用麦芽糖、蔗糖等糖类.测定了HY菌约930bp的16S rDNA序列,分类进化树显示其与哈维氏弧菌(Vibrio harveyi)XC08001聚为一簇.综合形态、生化和16S rDNA序列分析结果确定HY菌为哈维氏弧菌.以2×106cfu/只(蟹)的HY菌悬液注射健康梭子蟹成蟹(平均体重为400±25 g/只),致死率为35%;菌液浸泡感染梭子蟹仔蟹的半数致死剂量(LC50)为8.25×105cfu/cm3.上述结果表明分离的哈维氏弧菌对三疣梭子蟹具有致病性.
Breeding of portunus trituberculatus often occurs atypical symptoms in autumn and winter.In this study, bacteria were isolated from visceral and body cavity of Portunus trituberculatus, Gram stain was negative, the cell was rod-shaped, curved or comma-shaped, non-capsule, non-spore, polar flagella, strong mobility. Growth and biochemical tests showed that the growth of bacteria need salt, the most appropriate The growth of NaCl was 30 mg / cm3, the growth was vigorous at 28 ℃, the production of glucose was able to utilize glucose but not gas, the sugar of maltose, sucrose and other sugars could be utilized.The 16S rDNA sequence of 930bp of HY was determined, It was clustered with Vibrio harveyi XC08001.According to the morphological, biochemical and 16S rDNA sequence analysis results, HY strain was identified as Vibrio harveyi.With 2 × 106cfu / The median lethal dose (LC50) of swine crabs was 8.25 × 105cfu / cm3 after inoculation of the healthy crab crabs (mean body weight 400 ± 25 g / body) with a lethal rate of 35%. The above results showed that the isolated Vibrio harveyi pathogenicity of Portunus trituberculatus.