大西洋鲑源尾孢虫的形态观察与分子鉴定

Morphological Observation and Molecular Identification of Sporozoan(Henneguya)From Atlantic Salmon(Salmo salar)

本实验采用形态学法和18S rDNA基因序列比较相结合的方法,观察野生大西洋鲑Salmo salar肌肉中尾孢虫Henneguya sp.的形态特点,进行分类鉴定和系统地位研究。肉眼观察发现,该寄生虫寄生在鱼体的肌肉中,大量虫体聚集形成白色孢囊。镜检结果显示,该寄生虫壳面观呈倒卵形,具有尾凸,缝面观呈现纺锤形。选用特异性引物扩增了寄生虫18S rDNA基因片段,所得序列结合GenBank登陆的其他42个相关序列以Polypodium hydriforme为外群构建了系统进化树,表明所得序列与楚氏尾孢虫Henneguya zschokkei同源性最高(98.7%),遗传距离最小(0.0098)。

In this study,the morphological characteristics of sporozoan Henneguya sp.in the muscle of wild Atlantic salmon(Salmo salar)were observed by morphological method and taxonomic identification and systematic status of Henneguya sp.were studied by 18S rDNA gene sequence comparison.Macroscopic observation showed that the parasite was lived in the muscle of the fish,and a large number of the parasite bodies gathered to form white sporangia.Microscopic examination showed that the surface of the parasite was inverted oval,with tail convex,and the surface of the seam was spindle-shaped.Specific primers were selected to amplify the 18S rDNA gene fragment from the parasite,and stored in the GenBank with the access number MK774672.By combining the 18S rDNA sequences of other 42 relevant species sequences available in the GenBank a phylogenetictree was built with Polypodium hydriforme used as the outgroup.The results showed that the sequence had the highest homology with Henneguya zschokkei(98.7%)and the smallest genetic distance(0.0098).