Moorhead Sandra M, Dykes Gary A, Cursons Ray T
Food Safety Team, AgResearch Ltd., Ruakura MIRINZ Centre, East Street, Private Bag 3123, Hamilton, New Zealand.
J Microbiol Methods. 2003 Nov;55(2):425-32. doi: 10.1016/s0167-7012(03)00188-x.
The alternative sigma factor sigB gene is involved in the stress response regulation of Listeria monocytogenes, and contributes towards growth and survival in adverse conditions. This gene was examined to determine if it could be a useful indicator of lineage differentiation, similar to the established method based on ribotyping. The sigB sequence was resolved in four local L. monocytogenes strains and the phylogenetic relationship among these, and a further 21 sigB gene sequences from strains of different serotype and lineage including two Listeria innocua strains, obtained from the GenBank database were determined. The sigB nucleotide sequences of these 25 Listeria strains were then examined for single nucleotide polymorphic (SNP) sites that could differentiate between the three lineages. Based on nucleotide sequences L. monocytogenes lineage I/serotype 1/2b and 4b clustered together, lineage II/serotype 1/2a and 1/2c strains clustered together, lineage III/serotypes 4a and 4c strains clustered together and L. innocua strains clustered together as an outgroup. SNPs differentiating the three lineages were identified. Individual allele-specific PCR reactions based on these polymorphisms were successful in grouping known and a further 37 local L. monocytogenes isolates into the three lineages.
替代σ因子sigB基因参与单核细胞增生李斯特菌的应激反应调节，并有助于其在不利条件下的生长和存活。对该基因进行了检测，以确定它是否能像基于核糖体分型的既定方法一样，成为谱系分化的有用指标。解析了4株本地单核细胞增生李斯特菌菌株的sigB序列，并确定了它们之间以及从GenBank数据库获得的另外21个来自不同血清型和谱系菌株（包括2株无害李斯特菌菌株）的sigB基因序列之间的系统发育关系。然后检查这25株李斯特菌菌株的sigB核苷酸序列，寻找可区分三个谱系的单核苷酸多态性（SNP）位点。基于核苷酸序列，单核细胞增生李斯特菌谱系I/血清型1/2b和4b聚集在一起，谱系II/血清型1/2a和1/2c菌株聚集在一起，谱系III/血清型4a和4c菌株聚集在一起，无害李斯特菌菌株作为一个外群聚集在一起。确定了区分这三个谱系的SNP。基于这些多态性的单个等位基因特异性PCR反应成功地将已知的以及另外37株本地单核细胞增生李斯特菌分离株分为三个谱系。
