驴消化道3种线虫的扫描电镜观察及其系统发育分析

Scanning Electron Microscope Observation and Phylogenetic Analysis of Three Parasitic Nematode Species from Equus asinus Digestive Tract

为深入研究采集到的驴消化道3种寄生线虫的体表形态及其系统发育关系,本试验利用扫描电子显微镜技术首次对寄生于驴消化道内的马圆形线虫[Strongylus equinus(Mueller,1780)]、无齿圆形线虫[Strongylus edentatus(Looss,1900)]和杯状彼得洛夫线虫[Petrovinema poculatum(Looss,1900)]的体表形态进行详细观察和描述。提取线虫核糖体DNA内转录间隔区(ITS)基因,对其进行系统发育分析,建立系统发育树。扫描电子显微镜观察结果显示,马圆形线虫有内叶冠80枚,外叶冠180枚,雄虫生殖锥具有2对指状突起,一长一短;无齿圆形线虫有外叶冠80枚,雄虫尾部生殖锥较长,具有2对附属物,分别为乳头状和细长状;杯状彼得洛夫线虫外叶冠呈刺状,32枚,雄虫尾部具有1对小囊状附属物。系统发育分析结果显示,上述3种线虫形态学鉴定结果与系统发育树中该种的分类学地位一致。本试验结果为上述3种线虫的分类鉴定提供更精确的形态和分子生物学依据。

In order to comprehensively study the surface morphology and phylogenetic relationships of three parasitic nematodes collected from the Equus asinus digestive tract,the Strongylus equinus(Mueller,1780),Strongylus edentatus(Looss,1900),and Petrovinema poculatum(Looss,1900)were examined using scanning electron microscope(SEM).Additionally,the internal transcribed spacer(ITS)region of ribosomal DNA was extracted for phylogenetic analysis,and the phylogenetic tree was constructed.The SEM observations revealed detailed morphological features:S.equinus had 80 inner crowns,180 outer crowns,and the male genital cone with two pairs of digitate protrusions,one long and one short;S.edentatus had 80 outer crowns,the male had relatively long genital cone with two pairs of appendages,papillary and elongated;P.poculatum had 32 thorn-like outer crowns,and the male tail had a pair of small sac-like appendages.The phylogenetic analysis confirmed the taxonomic positions of these nematodes according to the obtained morphological identifications.The results of this study provide more accurate morphological and molecular biology-based evidence for the classification of these three nematode species.