Virulence plasmid interchange between strains ATCC 14028, LT2, and SL1344 of Salmonella enterica serovar Typhimurium
Virulence plasmid interchange between strains ATCC 14028, LT2, and SL1344 of Salmonella enterica serovar Typhimurium
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DOI：
10.1016/j.plasmid.2010.12.001
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发表时间：
2011-03-01
期刊：
影响因子：
2.6
通讯作者：
Casadesus, Josep
中科院分区：
文献类型：
--
作者：
Garcia-Quintanilla, Meritxell;Casadesus, Josep
在BALB/c小鼠模型中，肠道沙门氏菌鼠伤寒血清型的ATCC 14028和SL1344菌株比LT2的毒性更强。在ATCC 14208、LT2和SL1344菌株之间进行毒力质粒交换，在小鼠感染期间不会改变它们的竞争指数，这表明这三个质粒在功能上是等同的，并且它们对毒力的贡献与宿主背景无关。ATCC 14028和LT2菌株作为毒力质粒的接合供体比SL1344更有效。毒力质粒交换表明接合转移能力降低是SL1344质粒的特性，而非宿主菌株的特性。TraG蛋白中的一个A→V氨基酸替换似乎是导致SL1344毒力质粒接合转移降低的主要原因。在SL1344质粒与ATCC 14028和LT2质粒之间的tra操纵子中发现了其他序列差异。tra操纵子的差异可能反映了在实验室驯化之后或在环境中发生的遗传漂变。后者可能提供证据表明拥有接合转移功能在沙门氏菌群体中是一个中性特征，这一观点与大量毒力质粒为非接合性的沙门氏菌分离株是相符的。（C）2010爱思唯尔公司。保留所有权利。
Strains ATCC 14028 and SL1344 of Salmonella enterica serovar Typhimurium are more virulent than LT2 in the BALB/c mouse model. Virulence plasmid swapping between strains ATCC 14208, LT2, and SL1344 does not alter their competitive indexes during mouse infection, indicating that the three plasmids are functionally equivalent, and that their contribution to virulence is independent from the host background. Strains ATCC 14028 and LT2 are more efficient than SL1344 as conjugal donors of the virulence plasmid. Virulence plasmid swapping indicates that reduced ability of conjugal transfer is a property of the SL1344 plasmid, not of the host strain. An A V amino acid substitution in the TraG protein appears to be the major cause that reduces conjugal transfer in the virulence plasmid of SL1344. Additional sequence differences in the tra operon are found between the SL1344 plasmid and the ATCC 14028 and LT2 plasmids. Divergence in the tra operon may reflect the occurrence of genetic drift either after laboratory domestication or in the environment. The latter might provide evidence that possession of conjugal transfer functions is a neutral trait in Salmonella populations, a view consistent with the abundance of Salmonella isolates whose virulence plasmids are non-conjugative. (C) 2010 Elsevier Inc. All rights reserved.