Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes, RJ, Brazil.
Vet Parasitol. 2013 Mar 31;193(1-3):193-9. doi: 10.1016/j.vetpar.2012.11.024. Epub 2012 Nov 29.
Libyostrongylus sp. are nematodes that infect ostriches. Libyostrongylus douglassii was first described in ostriches from several countries in the world. Later Libyostrongylus dentatus was morphologically identified in ostriches in the USA and Brazil, and mixed infection is common in the latter country. The internal transcribed spacer (ITS) region of the ribosomal DNA gene is used for genetic variability assessment and phylogenetic reconstruction for many organisms. Through genetic analysis the status of different species morphologically defined was confirmed and a molecular method was developed to differentiate both species. ITS1, 5.8S, ITS2 regions of L. douglassii and L. dentatus were characterized. Regarding complete ITS region, the K2-p genetic distance between the species was 0.060 (SE 0.008) and the intra-specific distance was 0.002 (SE 0.001) for L. dentatus and 0.006 (SE 0.002) for L. douglassii. NJ and MP phylogenetic analysis of ITS1 and ITS2 regions indicated that both species belong to the Trichostrongylidae family, and are evolutionarily different, suported by high bootstrap value. Based on ITS DNA polymorphisms, a molecular approach was designed to detect both species. These results are the first molecular characterization of L. douglassii and L. dentatus, and provide new tools for the identification of these parasites of veterinary importance.
旋尾线虫属是一种感染鸵鸟的线虫。Douglassi 旋尾线虫最初在来自世界多个国家的鸵鸟中被描述。后来，在来自美国和巴西的鸵鸟中鉴定出了形态相似的 Dentatus 旋尾线虫，并且在后者国家中，混合感染很常见。核糖体 DNA 基因的内部转录间隔区（ITS）区域用于许多生物体的遗传变异评估和系统发育重建。通过遗传分析，确认了不同形态定义的物种的地位，并开发了一种区分这两个物种的分子方法。对 L. douglassii 和 L. dentatus 的 ITS1、5.8S 和 ITS2 区域进行了特征描述。关于完整的 ITS 区域，物种之间的 K2-p 遗传距离为 0.060（SE 0.008），种内距离为 0.002（SE 0.001）对于 L. dentatus 和 0.006（SE 0.002）对于 L. douglassii。ITS1 和 ITS2 区域的 NJ 和 MP 系统发育分析表明，这两个物种都属于 Trichostrongylidae 科，并且具有不同的进化关系，支持度很高。基于 ITS DNA 多态性，设计了一种分子方法来检测这两个物种。这些结果是对 L. douglassii 和 L. dentatus 的首次分子特征描述，为鉴定这些具有兽医重要性的寄生虫提供了新的工具。
