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目的探讨霍乱第7次大流行基因岛1(VSP-Ⅰ)在霍乱弧菌中的分布和变异特征。方法从美国国立生物技术信息中心的Gen Bank数据库中下载所有霍乱弧菌基因组数据,以霍乱第7次大流行代表菌株N16961的VSP-Ⅰ作为参考序列,筛查所下载霍乱弧菌基因组中的VSP-Ⅰ。使用MUMmer软件进行单核苷酸多态性(SNP)分析,Orth MCL软件进行同源基因分析,BLAST软件进行序列结构变异分析和功能注释。结果 VSP-Ⅰ广泛存在于霍乱弧菌中,其中霍乱第7次大流行的105株菌株中均携带VSP-Ⅰ,且其序列高度保守;其中94株菌的VSP-Ⅰ完全一致,仅在11株菌中分别存在1~14个SNP位点。而2株非O1非O139群菌株携带VSP-Ⅰ,但和大流行菌株相比,存在插入缺失等序列变异。同时,VSP-Ⅰ有9个共有保守基因,VC0183虽在所有菌株中均存在,但在2株非O1非O139菌株中长度发生改变。此外,VSP-Ⅰ携带5个与该岛的转移和整合相关的基因(VC0181~VC0185),VC0178编码马铃薯糖蛋白类似物,VC0180编码蛋白水解酶,二者可能与毒力相关。结论作为霍乱第7次大流行菌株中的特异性基因簇,VSP-Ⅰ已转移至非O1非O139群菌株中,并发生序列的变异。
Objective To investigate the distribution and variation of VSP-Ⅰ gene in Vibrio cholerae in the seventh outbreak of cholera. Methods All Vibrio cholerae genomic data were downloaded from the Gen Bank database of the National Center for Biotechnology Information. VSP-Ⅰ, the representative strain of the cholera seventh major pandemic strain N16961, was used as a reference sequence to screen VSPs in the Vibrio cholerae genome -Ⅰ. Single nucleotide polymorphism (SNP) analysis using MUMmer software, homologous gene analysis using Orth MCL software, sequence structure variation analysis and functional annotation with BLAST software. Results VSP-Ⅰ was found in Vibrio cholerae. VSP-Ⅰ was carried in all of the 105 strains of the cholera in the seventh pandemic. The sequence of VSP-Ⅰ was highly conserved. VSP-Ⅰ of 94 isolates was completely identical Strain in the presence of 1 to 14 SNP sites. However, two non-O1 non-O139 strains carried VSP-Ⅰ, but compared with the pandemic strains, there was a sequence variation such as insertion deletion. At the same time, there are 9 conserved genes in VSP-Ⅰ. Although VC0183 exists in all strains, its length changed in 2 non-O1 non-O139 strains. In addition, VSP-Ⅰ carries five genes (VC0181-VC0185) related to the island’s transfer and integration, VC0178 encodes potato glycoprotein analogues, and VC0180 encodes proteolytic enzymes, both of which may be related to virulence. Conclusion As a specific gene cluster in the seventh major pandemic strain of cholera, VSP-I has been transferred to non-O1 non-O139 group strains and sequence variation has occurred.