贪食迈阿密虫(Miamiensis avidus)ITS的PCR扩增与序列分析

PCR Amplification and Sequence Analysis of ITS rDNA of Miamiensis avidus

分离牙鲆(Paralichthys olivaceus)溃烂体表的盾纤毛虫,经形态学鉴定为贪食迈阿密虫(Miamiensis avidus),扩大培养后提取DNA进行ITS-5.8S序列的PCR扩增、测序及序列分析.结果显示贪食迈阿密虫与长拟尾丝虫(Parauronema longum)的遗传距离最近为0.074,在系统树中二者也聚成一支.表明病原体纤毛虫为不同于序列比对中其它纤毛虫种类,确定为贪食迈阿密虫,其与长拟尾丝虫的亲缘关系最近,是进化地位较高的一个类群.

The 8cuticociliatida ciliates which was isolated from Paralichthys olivaceus was identified as Miamiensis avidus based on morphology. The internal transcribed spacers （ITS1, 5.8S, ITS2） of ribosomal DNA were amplified by PCR, sequencing and analysis. These analyses indicate that Miamiensis avidus and Parauronema longum are always in one clade and the distance between them is smallest of all. The results showed that the pathogenic ciliate was Miamiensis avidus and the evolutionary status of Miamiensis avidus was closed to Parauronema longum the most.