Sympatric soil communities of Bacillus cereus sensu lato: population structure and potential plasmid dynamics of pXO1-and pXO2-like elements
Sympatric soil communities of Bacillus cereus sensu lato: population structure and potential plasmid dynamics of pXO1-and pXO2-like elements
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DOI：
10.1111/j.1574-6941.2009.00771.x
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发表时间：
2009-12-01
影响因子：
4.2
通讯作者：
Mahillon, Jacques
中科院分区：
文献类型：
--
作者：
Hu, Xiaomin;Swiecicka, Izabela;Mahillon, Jacques
从比利时两个邻近的地点收集了 80 个土传蜡样芽孢杆菌组分离株。使用五个染色体基因的多位点序列分型分析来评估它们的遗传关系和种群结构，同时通过 pXO1 和 pXO2 样质粒的存在、多样性和转移能力来衡量染色体外元件对种群动态的贡献。在全球范围内，细菌种群表现出广泛的多样性，包括与魏氏芽孢杆菌相关的重要耐冷菌株亚群。 pXO1 和 pXO2 样复制子存在于 12% 和 21% 的分离株中，但没有发现炭疽杆菌相关毒素基因。此外，只有一种含有 pXO2 相关质粒的分离株被证明能够动员小的非自接合质粒。有趣的是，观察到显示相同序列类型的几个蜡样芽孢杆菌分离株具有不同的质粒内容，表明水平基因交换的发生。类似地，在不同的细菌分离株中发现了许多具有相同序列的 pXO2 样复制子，因此强烈主张同域细菌之间的横向转移。
Eighty soil-borne Bacillus cereus group isolates were collected from two neighbouring geographical sites in Belgium. Their genetic relationships and population structure were assessed using Multilocus sequence typing analysis of five chromosomal genes, while the contribution of extrachromosomal elements to the population dynamics was gauged by the presence, diversity and transfer capacity of pXO1- and pXO2-like plasmids. Globally, the bacterial population displayed a broad diversity, including an important subpopulation of psychrotolerant isolates related to Bacillus weihenstephanensis. pXO1- and pXO2-like replicons were present in 12% and 21% of the isolates, but no Bacillus anthracis-related toxin genes were found. Furthermore, only one of the isolates containing a pXO2-related plasmid was shown to be able to mobilize small non-self-conjugative plasmids. Interestingly, several B. cereus sensu lato isolates displaying the same sequence type were observed to have different plasmid contents, suggesting the occurrence of horizontal gene exchange. Similarly, a number of pXO2-like replicons with identical sequences were found in distinct bacterial isolates, therefore strongly arguing for lateral transfers among sympatric bacteria.