| 摘要: |
| 从患有红体病的养殖大菱鲆（Scophthalmus maximus）的肌肉中分离得到一株优势菌并记为H1。经人工注射感染证实H1即为引起养殖大菱鲆红体病的病原菌,其半致死量LD50为2.82×105 CFU/mL，而低浓度（1.41×103 CFU/mL）没有造成死亡，但注射部位有脓肿现象，注射相同体积1.5%无菌生理盐水的对照组没有明显的症状，注射部位也无异常。革兰氏染色显示该菌为革兰氏阴性，菌体呈杆状，周生鞭毛。综合该菌的形态、常规生理生化特征和API32E鉴定结果，发现H1与迟钝爱德华氏菌的表性特征非常相似，相似率达到99.9%。在分子水平上对其16S RNA基因序列的测定、同源性分析，结果表明H1与迟钝爱德华氏菌的亲缘关系最近，相似度达到99%。综合上述研究结果，将该菌株初步鉴定为迟钝爱德华氏菌(Edwardsiella tarda)。
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| 关键词: 大菱鲆（Scophthalmus maximus） 红体病 细菌鉴定 迟钝爱德华氏菌(Edwardsiella tarda) |
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| 基金项目:国家863计划资助项目（2003AA622070）；国家“十一五”科技支撑计划资助项目（2006BAD09A11）;公益性行业（农业）科技专项项目（nyhyzx07-46） |
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| Isolation and identification of the pathogentic bacterium causing red body from cultured Turbot Scophthalmus maximus |
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DONG Li,WANG Yin-geng,ZHANG Zheng,QU jiang-bo,CHEN Xia
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| Abstract: |
| A dominant strain of the bacteria causing red body of turbot was isolated from the diseased turbot and designated as H1.In an artificial infection test ,all fish of the experimental group died in 15 days after intramuscularly being injected with a high bacterial suspention（1.41×109CFU/mL）, and the low bacterial suspention（1.41×CFU103/mL）did not cause any death, while the control group showed no signs all through the experimentation. The LD50 was calculated as 2.82×105CFU/mL.The moribund experimental fish had gross signs similar to the natural infected fish. The bacterium re- isolated from the challenged fish also had the same characteristics as H1, which proved that the isolated H1 was the pathogenic bacterium that triggered this red body disease. Different methods were used to identify the pathogenic bacterium. The bacterium is negative, rod in shape, peritrichous flagella under electronic microscope. Traditional biochemical identification revealed that H1 exhibited relatedness to Edwardsiella tarda, while the identification result by API 32E system indicated that H1 was E. tarda with 99.9% reliability . Its 16S ribosomal RNA gene sequences were analyzed , and it is shown from the anlysis results that this strain of bacterium has a close phylogenetic relation (99%)to E.tarda. In summary, the pathogenic bacterium was identified as E. tarda.
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| Key words: Scophthalmus maximus red body identification of bacterium Edwardsiella tarda |
