Research into the exchanges of the 0 antigen in Gram-negative bacteria

我研究了埃希氏菌。大肠杆菌0157菌株属于与0157:H7菌株不同的多个谱系。覆盖0157抗原基因簇及其侧翼区域的染色体区域（约59kb）的核苷酸序列表明，0157抗原基因簇的序列在序列水平上分为两个不同的组。有趣的是，两种类型的0157抗原基因簇的分布并不遵循菌株的系统发育谱系，这表明两种类型的0157抗原基因座的水平转移在大肠杆菌菌株中独立发生。此外，我们在序列相似性的连接点发现了重复序列，表明重复序列与0抗原基因簇周围的基因组重排有关。

I investigated Escherichia. coli 0157 strains belonging to multiple lineages different from that of the 0157:H7 strains. Nucleotide sequences of the chromosomal region (about 59 kb) covering the 0157-antigen gene clusters and its flanking regions revealed that sequences of 0157-antigen gene clusters were divided into two distinct groups at sequence level. Interestingly, distribution of the two types of the 0157-antigen gene clusters did not follow the phylogenetic lineages of the strains, suggesting that the horizontal transfer of both types of 0157-antigen locus has occurred indipendently among E. coli strains. Additionally, we found the repeat sequences in the junction points of sequence similarity, suggesting that the repeat sequences were associated with the genomic rearrangement around the 0-antigen gene clusters.