南昌市鸡蛔虫形态学与分子特征分析

Morphological and Molecular Characteristics of Ascaridia galli in Nanchang City

【目的】旨在通过分析鸡蛔虫的形态学和分子生物学特征,以了解南昌市鸡蛔虫与其他蛔虫的系统发育关系。【方法】观察并记录分离自南昌市鸡蛔虫的形态学特征,随后提取每个样本总DNA,PCR扩增ITS基因并测序,序列经NCBI比对后,对蛔虫样本ITS基因进行同源性分析和系统发育分析。【结果】所有蛔虫样本虫体呈淡黄色,头部可见唇瓣3片,近头端可见神经环。雄虫尾部向腹部弯曲而雌虫尾部尖直。蛔虫样本ITS基因大小均为1000 bp左右,与安徽、湖南、波兰鸡蛔虫分离株(登录号分别为:MN158368、OM876368、KY789470)以及与鸽蛔虫(登录号:JQ995321)高度同源,与鹅蛔虫(登录号:KC905082)同源性相对较高。实验分离的鸡蛔虫样本序列与其他国家或地区的鸡蛔虫序列及鸽蛔虫序列聚为一簇,与其他国家或地区的鸡蛔虫亲缘关系最近,与鸽蛔虫亲缘关系也很近;鹅蛔虫与其互为姊妹群,有独立的进化分支,亲缘关系相对较近。【结论】分离自南昌的鸡蛔虫与安徽、湖南、波兰鸡蛔虫分离株高度同源,亲缘关系很近,初步判定它们具有相同的起源,同时也表明南昌地区鸡蛔虫可能由安徽、湖南等地区流入;而与鹅蛔虫同源性相对较高,但具有一定差异性,说明种间ITS基因存在一定变异,是分析蛔虫种间发育关系的良好标记基因。鸡蛔虫的形态学和分子特征分析可为鸡蛔虫的鉴定以及鸡蛔虫病的防控奠定理论基础。

[Objective]The study aimed to reveal the phylogenetic relationship between A.gallis isolated from Nanchang City and other A.gallis by analyzing their morphological and molecular biological characteristics.[Method]Themorphological characteristics of A.gallis were observed and recorded,and then DNA of each sample was extracted,through PCR,ITS gene was amplified and sequenced so as to obtain the sequences.All sequences were blasted in GenBank,and then homology and phylogenetic analysis of ITS gene were performed for all samples.[Results]A.gallis were pale yellow with three lips on the head and a nerve ring near the head.The male tail curved towards the abdomen,while the female tail pointed straight.ITS gene sequences of A.galli were almost 1000 bp,which was highly homologous to A.galli isolated from Anhui Province(MN158368),Hunan Province(OM876368),and Polish(KY789470).Also,it is highly homologous with Ascaridia columbae(JQ995321),and relatively highly homologous with Ascaridia anseris(KC905082).All the sequences of A.galliin this study were clustered with the sequences of A.galli and A.columbae from other countries or regions.They were most closely related to the A.galli from other countries or regions and were relatively close with the A.columbae.The large branches formed by A.galli,A.columbae,and A.anseris were sister groups to each other,with independent evolutionary branches and relatively close affinities.[Conclusion]The sequences of A.galli isolated from Nanchang City were highly homologous and closely related to other sequences of A.galli isolated from Poland and Anhui/Hunan Provinces,indicating that they may have the same origin,and also showing that A.galli isolated from Nanchang was probably imported from Anhui and Hunan Provinces.Also,the homology with the A.anseris was relatively high.Still,there was some difference,which indicated that some variations in the interspecific ITS gene,which is a good marker gene to analyze the interspecific developmental relationship in Ascaris species.The analysis of morphological and molecular characteristics of A.galli could lay a theoretical foundation for the identification and prevention and control of A.galli.