Adeolu Mobolaji, Gupta Radhey S
Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8N 3Z5, Canada.
Antonie Van Leeuwenhoek. 2014 Jun;105(6):1049-72. doi: 10.1007/s10482-014-0164-x. Epub 2014 Apr 18.
The genus Borrelia contains two groups of organisms: the causative agents of Lyme disease and their relatives and the causative agents of relapsing fever and their relatives. These two groups are morphologically indistinguishable and are difficult to distinguish biochemically. In this work, we have carried out detailed comparative genomic analyses on protein sequences from 38 Borrelia genomes to identify molecular markers in the forms of conserved signature inserts/deletions (CSIs) that are specifically found in the Borrelia homologues, and conserved signature proteins (CSPs) which are uniquely present in Borrelia species. Our analyses have identified 31 CSIs and 82 CSPs that are uniquely shared by all sequenced Borrelia species, providing molecular markers for this group of organisms. In addition, our work has identified 7 CSIs and 21 CSPs which are uniquely found in the Lyme disease Borrelia species and eight CSIs and four CSPs that are specific for members of the relapsing fever Borrelia group. Additionally, 38 other CSIs, in proteins which are uniquely found in Borrelia species, also distinguish these two groups of Borrelia. The identified CSIs and CSPs provide novel and highly specific molecular markers for identification and distinguishing between the Lyme disease Borrelia and the relapsing fever Borrelia species. We also report the results of average nucleotide identity (ANI) analysis on Borrelia genomes and phylogenetic analysis for these species based upon 16S rRNA sequences and concatenated sequences for 25 conserved proteins. These analyses also support the distinctness of the two Borrelia clades. On the basis of the identified molecular markers, the results from ANI and phylogenetic studies, and the distinct pathogenicity profiles and arthropod vectors used by different Borrelia spp. for their transmission, we are proposing a division of the genus Borrelia into two separate genera: an emended genus Borrelia, containing the causative agents of relapsing fever and a novel genus, Borreliella gen. nov., containing the causative agents of Lyme disease.
莱姆病的病原体及其相关物种，以及回归热的病原体及其相关物种。这两类在形态上无法区分，在生化特性上也难以辨别。在这项研究中，我们对38个疏螺旋体基因组的蛋白质序列进行了详细的比较基因组分析，以识别保守特征插入/缺失（CSIs）形式的分子标记，这些标记在疏螺旋体同源物中特异性存在，以及疏螺旋体物种中独特存在的保守特征蛋白（CSPs）。我们的分析确定了31个CSIs和82个CSPs，它们为所有已测序的疏螺旋体物种所特有，为这组生物体提供了分子标记。此外，我们的研究还确定了7个CSIs和21个CSPs，它们仅在莱姆病疏螺旋体物种中发现，以及8个CSIs和4个CSPs，它们是回归热疏螺旋体组成员所特有的。此外，在疏螺旋体物种中独特发现的蛋白质中的38个其他CSIs也区分了这两类疏螺旋体。所识别的CSIs和CSPs为莱姆病疏螺旋体和回归热疏螺旋体物种的鉴定和区分提供了新颖且高度特异的分子标记。我们还报告了疏螺旋体基因组的平均核苷酸同一性（ANI）分析结果以及基于16S rRNA序列和25个保守蛋白的串联序列对这些物种进行的系统发育分析结果。这些分析也支持了两个疏螺旋体进化枝的独特性。基于所识别的分子标记、ANI和系统发育研究的结果，以及不同疏螺旋体物种用于传播的不同致病性特征和节肢动物载体，我们提议将疏螺旋体属划分为两个独立的属：一个修订后的疏螺旋体属，包含回归热的病原体；一个新属，新疏螺旋体属（Borreliella gen. nov.），包含莱姆病的病原体。
