Mtshali Phillip Senzo, Mtshali Moses Sibusiso
Veterinary Parasitology Programme, Research and Scientific Services Department, National Zoological Gardens of South Africa, Pretoria 0001, South Africa.
School of Molecular and Life Sciences, University of Limpopo, Private Bag X 1106, Sovenga, Polokwane 0727, South Africa.
Biology (Basel). 2025 Mar 28;14(4):355. doi: 10.3390/biology14040355.
is one of the most important etiological agents of bovine babesiosis, a tick-borne disease posing a major threat in the livestock industry globally, including South Africa. Despite the huge economic impact of cattle babesiosis in South Africa, antigenic variation observed among strains worldwide has impeded the successful development of a single vaccine with the potential to eliminate the disease. As such, there is still a dearth of information regarding the conservation of genes encoding functionally important proteins that play a crucial role during the invasion of bovine erythrocytes by merozoites. Fifty blood samples previously collected from cattle in eight provinces of South Africa were genetically tested for the presence of DNA fragments using four nested PCR-based assays. The genes targeted coded for I-I restriction fragment, rhoptry-associated protein 1 (), apical membrane antigen 1 () and β-tubulin (). PCR-generated fragments of randomly selected samples were sequenced. BLAST searches in GenBank were performed with newly determined sequences to search for homologous sequences. Neighbor-joining phylogenies were inferred from aligned, contiguous sequences of , and genes. Nested PCR assays generated single fragments of 170 bp, 472 bp, 765 bp and 302 bp for I-I, , and fragments, respectively. Of the 50 bovine samples tested by nested PCR, 82% (42/50; 95% CI = 69.2-90.2%), 68% (34/50; 95% CI = 54.2-79.2%), 50% (25/50; 95% CI = 36.6-63.4%) and 46% (23/50; 95% CI = 33.0-59.6%) possessed -specific I-I, , and DNA fragments, respectively. The , and sequences of South African isolates shared 98-100% similarity with previously reported sequences of strains originating from cattle in countries other than South Africa. The high genetic conservation observed among geographical isolates of suggests the conserved functional role of BgRAP-1 and BgAMA-1 proteins as potential candidates that could be incorporated in recombinant subunit vaccines.
是牛巴贝斯虫病最重要的病原体之一，牛巴贝斯虫病是一种由蜱传播的疾病，对包括南非在内的全球畜牧业构成重大威胁。尽管牛巴贝斯虫病在南非造成了巨大的经济影响，但全球各菌株间观察到的抗原变异阻碍了开发一种有潜力消除该病的单一疫苗。因此，关于编码在裂殖子侵入牛红细胞过程中起关键作用的功能重要蛋白的基因的保守性，仍然缺乏相关信息。使用四种基于巢式PCR的检测方法，对之前从南非八个省份的牛身上采集的50份血液样本进行基因检测，以检测DNA片段的存在。靶向的基因编码I-I限制性片段、棒状体相关蛋白1（）、顶膜抗原1（）和β-微管蛋白（）。对随机选择的样本经PCR产生的片段进行测序。利用新确定的序列在GenBank中进行BLAST搜索，以寻找同源序列。从、和基因的比对连续序列推断邻接法系统发育树。巢式PCR检测分别为I-I、、和片段产生了170bp、472bp、765bp和302bp的单一片段。在通过巢式PCR检测的50份牛样本中，分别有82%（42/50；95%CI = 69.2 - 90.2%）、68%（34/50；95%CI = 54.2 - 79.2%）、50%（25/50；95%CI = 36.6 - 63.4%）和46%（23/50；95%CI = 33.0 - 59.6%）含有特异性的I-I、、和DNA片段。南非分离株的、和序列与之前报道的源自南非以外国家牛的菌株序列具有98 - 100%的相似性。在地理分离株中观察到的高度遗传保守性表明BgRAP - 1和BgAMA - 1蛋白具有保守的功能作用，可作为潜在候选物纳入重组亚单位疫苗。
