Division of Parasitology, Kimron Veterinary Institute, Bet Dagan, Israel.
Parasitology. 2012 Mar;139(3):317-23. doi: 10.1017/S0031182011001995. Epub 2011 Nov 11.
The aim of this study was to compare the genetic diversity of the single copy Bv80 gene sequences of Babesia bovis in populations of attenuated and virulent parasites. PCR/ RT-PCR followed by cloning and sequence analyses of 4 attenuated and 4 virulent strains were performed. Multiple fragments in the range of 420 to 744 bp were amplified by PCR or RT-PCR. Cloning of the PCR fragments and sequence analyses revealed the presence of mixed subpopulations in either virulent or attenuated parasites with a total of 19 variants with 12 different sequences that differed in number and type of tandem repeats. High levels of intra- and inter-strain diversity of the Bv80 gene, with the presence of mixed populations of parasites were found in both the virulent field isolates and the attenuated vaccine strains. In addition, during the attenuation process, sequence analyses showed changes in the pattern of the parasite subpopulations. Despite high polymorphism found by sequence analyses, the patterns observed and the number of repeats, order, or motifs found could not discriminate between virulent field isolates and attenuated vaccine strains of the parasite.
本研究旨在比较弱毒和强毒巴贝斯虫（Babesia bovis）单拷贝 Bv80 基因序列的遗传多样性。对 4 株弱毒和 4 株强毒株进行了 PCR/RT-PCR 扩增、克隆和序列分析。PCR 或 RT-PCR 扩增出 420 至 744bp 大小的多个片段。克隆 PCR 片段并进行序列分析表明，无论是强毒还是弱毒寄生虫中均存在混合亚群，共有 19 种变体，其中 12 种不同序列在串联重复的数量和类型上存在差异。在强毒田间分离株和弱毒疫苗株中均发现 Bv80 基因存在高度的株内和株间多样性，同时存在寄生虫的混合种群。此外，在减毒过程中，序列分析显示寄生虫亚群的模式发生了变化。尽管序列分析发现了高度多态性，但观察到的模式和重复、顺序或基序的数量不能区分强毒田间分离株和弱毒疫苗株。
