东方次睾吸虫囊蚴的分子鉴定

Molecular identification of metacercaria of Metorchis orientalis

为了鉴定淡水鱼体内的囊蚴是否为东方次睾吸虫囊蚴,试验采用PCR方法分别对5尾麦穗鱼的吸虫囊蚴核糖体内转录间隔区（ITS）进行扩增、克隆及序列分析。结果表明：5个样品的ITS序列长度均为1 077 bp,ITS1、5.8S和ITS2的长度分别为629 bp、160 bp和288 bp,5个样品的ITS核苷酸同源性为99.7%~100%;与Gen Bank中已发表的东方次睾吸虫成虫ITS1和ITS2序列的核苷酸同源性分别为98.7%~98.9%和99.7%~100%;基于ITS2序列构建的进化树显示,除布氏姜片吸虫外,每科均形成一个分支;5个东方次睾吸虫囊蚴与东方次睾吸虫成虫在同一分支上,与华支睾吸虫关系最近。说明麦穗鱼体内的囊蚴为东方次睾吸虫囊蚴。

To identify whether the metacercariae of trematode in freshwater fishes is the metacercaria of Metorchis orientalis（ M. orientalis）,the ribosomal internal transcribed spacer（ ITS） sequences of trematode metacercariae in five samples from Pseudorasbora parva（ P. parva） were amplified and cloned for sequence analysis using PCR method,respectively. The results showed that the length of the sequences of ITS from five samples was all 1 077 bp,and the lengths of the sequences of ITS1,5. 8S and ITS2 were 629 bp,160 bp and 288 bp,respectively. The nucleotide homology of ITS was 99. 7% to 100% among five samples,which shared 98. 7% to 98. 9% and 99. 7% to 100% homology with the nucleotide sequences of ITS1 and ITS2 from adult M. orientalis published in Gen Bank,respectively. The phylogenetic tree constructed based on the sequences of ITS2 showed that every family formed one clade,except Fasciolopsis buski. Five metacercaria samples and the adult worm of M. orientalis were in the same branch,and they were closely related with Clonorchis sinensis. The results indicate that the metacercariae in P.parva were the metacercariae of M. orientalis.