PDF(Pubmed)
Abstract：
Arcanobacterium hippocoleae is a Gram-positive fastidious bacterium and is occasionally isolated from the reproductive tract of apparently healthy mares (Equus caballus) or from mares with reproductive tract abnormalities. Apart from a few 16S rRNA gene-based GenBank sequences and one recent report on complete genome assembly, detailed genomic sequence and clinical experimental data are not available on the bacterium. Recently, we observed an unusual increase in the detection of the organism from samples associated with mare reproductive failures in Atlantic Canada. Two colony morphotypes (i.e., small, and large) were detected in culture media, which were identified as A. hippocoleae by MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. Here, we report the whole genome sequencing and characterization of the morphotype variants. The genome length of the large phenotypes was between 2.42 and 2.43, and the small phenotype was 1.99 Mbs. The orthologous nucleotide identity between the large colony phenotypes was ~99%, and the large and small colony phenotypes was between 77.86 and 78.52%, which may warrant the classification of the two morphotypes into different species. Phylogenetic analysis based on 16S rRNA genes or concatenated housekeeping genes grouped the small and large colony variants into two different genotypic clusters. The UvrA protein, which is part of the nucleotide excision repair (NER) system, and 3-isopropoylmalate dehydratase small subunit protein expressed by the leuD gene were identified as potential virulence factors in the large and small colony morphotypes, respectively. However, detailed functional studies will be required to determine the exact roles of these and other identified hypothetical proteins in the cellular metabolism and potential pathogenicity of A. hippocoleae in mares.
摘要：
海马弧菌是革兰氏阳性细菌，偶尔会从明显健康的母马（Equuscaballus）的生殖道或生殖道异常的母马中分离出来。除了一些基于16SrRNA基因的GenBank序列和一份关于完整基因组组装的最新报告外，该细菌没有详细的基因组序列和临床实验数据。最近,我们观察到，在加拿大大西洋地区，从与母马繁殖失败相关的样本中检测到的生物体异常增加。两种菌落形态(即，小,和大)在培养基中检测到，通过MALDI-TOF质谱和16SrRNA基因测序鉴定为海马A。这里,我们报告了形态型变异的全基因组测序和表征。年夜表型的基因组长度在2.42～2.43之间，小表型为1.99Mbs。大菌落表型之间的直系同源核苷酸同一性为〜99％，大菌落和小菌落表型在77.86和78.52%之间，这可能保证将两种形态类型分类为不同的物种。基于16SrRNA基因或串联的管家基因的系统发育分析将小菌落变体和大菌落变体分为两个不同的基因型簇。UvrA蛋白，它是核苷酸切除修复（NER）系统的一部分，和3-异丙酰基苹果酸脱水酶小亚基蛋白表达的leuD基因被鉴定为潜在的毒力因子在大和小的菌落形态，分别。然而,需要进行详细的功能研究，以确定这些和其他已鉴定的假设蛋白质在细胞代谢中的确切作用以及海马A.
