Phylogenetic trees and bioinformatic analyses of 36 M. bovis chromosomes sequenced in this study and additional available chromosomes of M. bovis and both genotype 1 and 2 M. bovoculi, showed there are two genotypes (1 and 2) of M. bovis. The two M. bovis genotypes share a core of 2015 genes, with 121 and 186 genes specific to genotype 1 and 2, respectively. The two genotypes differ by their chromosome size and prophage content, encoded protein variants of the virulence factor hemolysin, and by their affiliation with different plasmids. Eight plasmid types were identified in this study, with types 1 and 6 observed in 88 and 56% of genotype 2 strains, respectively, and absent from genotype 1 strains. Only type 1 plasmids contained one or two gene copies encoding filamentous haemagglutinin-like proteins potentially involved with adhesion. A core of 1403 genes was shared between the genotype 1 and 2 strains of both M. bovis and M. bovoculi, which encoded a total of nine predicted outer membrane proteins.
There are two genotypes of M. bovis that differ in both chromosome content and plasmid profiles and thus may not equally associate with IBK. Immunological reagents specifically targeting select genotypes of M. bovis, or all genotypes of M. bovis and M. bovoculi together could be designed from the outer membrane proteins identified in this study.
本研究中测序的36种牛分枝杆菌染色体的系统发育树和生物信息学分析,以及牛分枝杆菌和基因型1和2种牛分枝杆菌的其他可用染色体,显示牛分枝杆菌有两种基因型(1和2)。两种牛分枝杆菌基因型共享2015年基因的核心,分别有121个和186个基因特异于基因型1和2。这两种基因型的染色体大小和原抗原含量不同,编码的毒力因子溶血素的蛋白质变体,以及它们与不同质粒的联系。在这项研究中鉴定了八种质粒类型,在基因型2菌株的88%和56%中观察到类型1和6,分别,并且不存在于基因型1菌株中。只有1型质粒含有一个或两个编码可能与粘附有关的丝状血凝素样蛋白的基因拷贝。1403个基因的核心在牛分枝杆菌和牛分枝杆菌的基因型1和2菌株之间共享,总共编码了九种预测的外膜蛋白。
牛分枝杆菌有两种基因型,它们的染色体含量和质粒谱均不同,因此可能与IBK不相等。特异性靶向选择牛分枝杆菌基因型的免疫试剂,或牛分枝杆菌和牛分枝杆菌的所有基因型可以从这项研究中鉴定的外膜蛋白设计。