本文以染病鲈鱼为试验材料,对其肝脏的致病菌进行分离、纯化、鉴定,并分析了致病菌与鲈鱼免疫信号通路的相互关系.结果表明,经分离、纯化,从染病鲈鱼肝脏中得到一株菌株VP-5.VP-5 呈球杆状、弧形,有单鞭毛,运动活跃,为革兰氏阴性菌,对酪氨酸、葡萄糖、甘露醇等反应阳性,对蔗糖、阿拉伯糖和棉子糖等反应阴性,其 16S rRNA和TDH1 基因序列与副溶血弧菌的亲缘关系非常接近.经综合鉴定,致病菌VP-5 为副溶血弧菌.鲈鱼受到副溶血弧菌VP-5 感染后,免疫信号通路基因CD63、CXCR4、IL-8 在鲈鱼肝脏组织中 12h和 24 h时的相对表达量与无菌生理盐水对照组(CK)相比差异显著(P<0.05);在表皮组织中 24h和 36h时的相对表达量与无菌生理盐水对照组(CK)相比差异显著(P<0.05).证实鲈鱼肝脏组织免疫信号通路基因的表达与副溶血弧菌VP-5 的感染正相关,相对于表皮组织反应更快.鲈鱼的免疫信号通路基因CD63、CXCR4、IL-8 积极反应于致病菌,这些基因的快速表达会引发鲈鱼自身免疫应答,增强鲈鱼抵抗致病菌的能力.
This paper used infected Lateolabrax japonicus as the experimental material to isolate,purify and iden-tify the pathogenic bacteria in its liver,and analyzed the relationship between the pathogenic bacteria and the immune signaling pathway of Lateolabrax japonicus.The results showed that a strain VP-5 was isolated and purified from in-fected Lateolabrax japonicus liver.VP-5 was rod-shaped and arc-shaped,with a single flagella and active movement.It was a Gram negative bacterium that reacted positively to tyrosine,glucose,mannitol and other substances,but negatively to sucrose,arabinose and raffinose.Its 16S rRNA and TDH1 gene sequences were closely related to Vibrio parahaemoly-ticus.After comprehensive identification,the pathogenic bacterium VP-5 was Vibrio parahaemolyticus.After being infected with Vibrio parahaemolyticus VP-5,the relative expression levels of immune signaling pathway genes CD63,CXCR4 and IL-8 in the liver tissue of Lateolabrax japonicus at 12 and 24 hours were significantly different from those in the sterile saline control group(CK)(P<0.05);the relative expression levels in epidermal tissue at 24 and 36 hours showed significant differences compared with the sterile saline control group(CK)(P<0.05).It was confirmed that the expression of immune signaling pathway genes in the liver tissue of Lateolabrax japonicus was positively correlated with the infection of Vibrio parahaemolyticus VP-5,with a faster response compared with the epidermal tissue.The immune signaling pathway genes CD63,CXCR4 and IL-8 in Lateolabrax japonicus actively responded to pathogenic bacteria.The rapid expression of these genes could trigger the self immune response of Lateolabrax japonicus and enhance its ability to resist pathogenic bacteria.