Comparative genomics of clinical and environmental Vibrio mimicus
Comparative genomics of clinical and environmental Vibrio mimicus
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DOI：
10.1073/pnas.1013825107
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发表时间：
2010-12-07
影响因子：
11.1
通讯作者：
Colwell, Rita R.
中科院分区：
文献类型：
--
作者：
Hasan, Nur A.;Grim, Christopher J.;Colwell, Rita R.
拟态弧菌究竟是霍乱弧菌的变种，还是一个独立的物种，一直是分类学争议的主题。为了解决这个问题，进行了基因组分析。临床分离物V. mimicus MB451和环境分离物VM223的基因组分别包含约4,347,971和4,313,453 bp，分别编码3,802和3,290个orf。与其他弧菌一样，染色体I （C-I）主要含有生长和生存所必需的基因，而染色体II （C-II）则含有适应环境变化的基因。c - 1含有许多毒力基因，包括一些以前未在拟弧菌中报道的基因，如甘露糖敏感血凝素（MSHA）和肠毒素溶血素（HlyA）；C-II编码弧菌致病性岛2 （VPI-2）和第七大流行弧菌岛II （VSP-II）基因簇的一个变体。C-II广泛的基因组重排表明它是弧菌属进化和物种形成的热点。本研究发现的毒力区数量（VSP-II、MSHA、HlyA、IV型pilin、PilE和整合子整合酶IntI4）在临床菌株和环境菌株之间的潜在毒力基因无显著差异，提示这些基因也可能在环境中发挥作用，环境中可能出现致病性菌株。观察到与第七次大流行前霍乱弧菌原型株的显著基因组同源性，系统发育分析结果支持这样的假设，即在进化过程中，拟态弧菌和霍乱弧菌从具有第六次大流行原型基因组主干的共同祖先分化而来。
Whether Vibrio mimicus is a variant of Vibrio cholerae or a separate species has been the subject of taxonomic controversy. A genomic analysis was undertaken to resolve the issue. The genomes of V. mimicus MB451, a clinical isolate, and VM223, an environmental isolate, comprise ca. 4,347,971 and 4,313,453 bp and encode 3,802 and 3,290 ORFs, respectively. As in other vibrios, chromosome I (C-I) predominantly contains genes necessary for growth and viability, whereas chromosome II (C-II) bears genes for adaptation to environmental change. C-I harbors many virulence genes, including some not previously reported in V. mimicus, such as mannose-sensitive hemagglutinin (MSHA), and enterotoxigenic hemolysin (HlyA); C-II encodes a variant of Vibrio pathogenicity island 2 (VPI-2), and Vibrio seventh pandemic island II (VSP-II) cluster of genes. Extensive genomic rearrangement in C-II indicates it is a hot spot for evolution and genesis of speciation for the genus Vibrio. The number of virulence regions discovered in this study (VSP-II, MSHA, HlyA, type IV pilin, PilE, and integron integrase, IntI4) with no notable difference in potential virulence genes between clinical and environmental strains suggests these genes also may play a role in the environment and that pathogenic strains may arise in the environment. Significant genome synteny with prototypic pre-seventh pandemic strains of V. cholerae was observed, and the results of phylogenetic analysis support the hypothesis that, in the course of evolution, V. mimicus and V. cholerae diverged from a common ancestor with a prototypic sixth pandemic genomic backbone.