Zhou Ling, Sriram Rama, Visvesvara Govinda S, Xiao Lihua
Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
J Eukaryot Microbiol. 2003;50 Suppl:522-6. doi: 10.1111/j.1550-7408.2003.tb00617.x.
Naegleria spp. are widely distributed free-living amebas, but one species in the genus, N. fowleri, causes acute fulminant primary amebic meningoencephalitis in humans and other animals. Thus, it is important to differentiate N. fowleri from the rest in the genus of Naegleria, and to develop tools for the detection of intra-specific genetic variations. In this study, one isolate each of N. australiensis, N. gruberi, N. jadini, and N. lovaniensis and 22 isolates of N. fowleri were characterized at the internal transcribed spacers (ITS) and mitochondrial small subunit rRNA (mtSSU rRNA) gene. The mtSSU rRNA primers designed amplified DNA of all isolates, with distinct sequences obtained from all species examined. In contrast, the ITS primers only amplified DNA from N. lovaniensis and N. fowleri, with minor sequence differences between the two. Three genotypes of N. fowleri were found among the isolates analyzed in both the mtSSU rRNA gene and ITS. The extent of sequence variation was greater in the mtSSU rRNA gene, but the ITS had the advantage of length polymorphism. These data should be useful in the development of molecular tools for rapid species differentiation and genotyping of Naegleria spp.
耐格里属变形虫是广泛分布的自由生活变形虫，但该属中的福氏耐格里变形虫会在人类和其他动物中引发急性暴发性原发性阿米巴脑膜脑炎。因此，区分福氏耐格里变形虫与耐格里属中的其他变形虫，并开发检测种内基因变异的工具非常重要。在本研究中，对澳大利亚耐格里变形虫、格氏耐格里变形虫、贾氏耐格里变形虫和洛氏耐格里变形虫各一个分离株以及22个福氏耐格里变形虫分离株的内转录间隔区（ITS）和线粒体小亚基rRNA（mtSSU rRNA）基因进行了特征分析。设计的mtSSU rRNA引物扩增了所有分离株的DNA，从所有检测物种中获得了不同的序列。相比之下，ITS引物仅扩增了洛氏耐格里变形虫和福氏耐格里变形虫的DNA，两者之间存在微小的序列差异。在所分析的分离株中，在mtSSU rRNA基因和ITS中均发现了三种福氏耐格里变形虫基因型。mtSSU rRNA基因中的序列变异程度更大，但ITS具有长度多态性的优势。这些数据应有助于开发用于快速区分耐格里属变形虫物种和进行基因分型的分子工具。
