Kuchboev Abdurakhim E, Krücken Jürgen, Ruziev Bakhtiyor H, von Samson-Himmelstjerna Georg
Institute of the Gene Pool Plants and Animals of Uzbekistan Academy of Sciences, Bogishamol str. 232, 100053, Tashkent, Uzbekistan.
Parasitol Res. 2015 Apr;114(4):1355-64. doi: 10.1007/s00436-015-4313-6. Epub 2015 Jan 18.
Protostrongylids are important pulmonary parasites of ungulates, particularly caprines. Their complex life cycles involve terrestrian gastropods as intermediate hosts. Morphological discrimination of larvae in feces and snails is impossible to the species level, and molecular data are missing for many species. To improve diagnosis and epidemiology of protostrongylids, this study describes internal transcribed spacer 2 (ITS-2) sequences for five protostrongylid and one metastrongylid species from Uzbekistan. Morphological and molecular analyses identified Protostrongylus rufescens, Protostrongylus hobmaieri, Protostrongylus sp., Spiculocaulus leuckarti, and Cystocaulus ocreatus. Sequence differences between ITS-2 were sufficient to allow species identification, e.g., in the Protostrongylinae intraspecific and interspecific genetic distances ranged between 0-0.01 and 0.05 and 0.16, respectively. There was one exception in the Elaphostrongylidae with identical ITS-2 sequences in Elaphostrongylus cervi and Elaphostrongylus rangiferi questioning their status as valid species. Maximum likelihood analysis sequences largely supported the currently assumed phylogenetic relationships among Protostrongylidae as predicted using morphological characters. The monophyly of the subfamilies Varestrongylinae, Elaphostrongylinae, and Protostrongylinae was corroborated with support values in Shimodaira-Hasegawa or Bayesian modifications of the approximate likelihood ratio test (aLRT) ≥97%, but support for Muellerinae was weak (8 and 52%, respectively) since Muellerius capillaris differs significantly from the other Muellerinae. On the genus level, paraphyly of the genus Protostrongylus was confirmed since the members of the genera Spiculocaulus and Orthostrongylus were located within the Protostrongylus cluster (aLRT ≥99%). Maximum likelihood unequivocally assigned every unique sequence to the correct species confirming suitability of ITS-2 regions for diagnosis protostrongylids except of E. cervi and E. rangiferi.
原圆科线虫是有蹄类动物，尤其是山羊的重要肺部寄生虫。它们复杂的生命周期涉及陆生腹足类动物作为中间宿主。粪便和蜗牛中幼虫的形态学鉴别无法达到种的水平，而且许多物种缺少分子数据。为了改善原圆科线虫的诊断和流行病学，本研究描述了来自乌兹别克斯坦的5种原圆科线虫和1种后圆科线虫的内转录间隔区2（ITS-2）序列。形态学和分子分析鉴定出了红原圆线虫、霍氏原圆线虫、原圆线虫属未定种、鲁氏细颈线虫和有囊尾泡线虫。ITS-2之间的序列差异足以进行物种鉴定，例如，在原圆亚科中，种内和种间遗传距离分别在0-0.01和0.05与0.16之间。在枝睾属线虫中存在一个例外，鹿枝睾线虫和驯鹿枝睾线虫的ITS-2序列相同，这对它们作为有效物种的地位提出了质疑。最大似然分析序列在很大程度上支持了目前根据形态特征预测的原圆科线虫之间的系统发育关系。瓦雷原圆亚科、枝睾原圆亚科和原圆亚科的单系性在近似似然比检验（aLRT）的Shimodaira-Hasegawa或贝叶斯修正中得到了支持值≥97%的证实，但对缪勒亚科的支持较弱（分别为8%和52%），因为毛细缪勒线虫与其他缪勒亚科有显著差异。在属的水平上，原圆线虫属的并系性得到了证实，因为细颈线虫属和正圆线虫属的成员位于原圆线虫属聚类中（aLRT≥99%）。最大似然法明确地将每个独特序列归为正确的物种，证实了ITS-2区域除鹿枝睾线虫和驯鹿枝睾线虫外对诊断原圆科线虫的适用性。
