Vilches Silvia, Urgell Cecilia, Merino Susana, Chacón Matilde R, Soler Lara, Castro-Escarpulli Graciela, Figueras Maria Jose, Tomás Juan M
Departamento Microbiología, Facultad Biología, Universidad de Barcelona, Barcelona, Spain.
Appl Environ Microbiol. 2004 Nov;70(11):6914-9. doi: 10.1128/AEM.70.11.6914-6919.2004.
We have investigated the existence and genetic organization of a functional type III secretion system (TTSS) in a mesophilic Aeromonas strain by initially using the Aeromonas hydrophila strain AH-3. We report for the first time the complete TTSS DNA sequence of an Aeromonas strain that comprises 35 genes organized in a similar disposition as that in Pseudomonas aeruginosa. Using several gene probes, we also determined the presence of a TTSS in clinical or environmental strains of different Aeromonas species: A. hydrophila, A. veronii, and A. caviae. By using one of the TTSS genes (ascV), we were able to obtain a defined insertion mutant in strain AH-3 (AH-3AscV), which showed reduced toxicity and virulence in comparison with the wild-type strain. Complementation of the mutant strain with a plasmid vector carrying ascV was fully able to restore the wild-type toxicity and virulence.
我们最初使用嗜水气单胞菌菌株AH-3，研究了嗜温气单胞菌菌株中功能性III型分泌系统（TTSS）的存在及其基因组织。我们首次报告了气单胞菌菌株完整的TTSS DNA序列，该序列由35个基因组成，其排列方式与铜绿假单胞菌中的相似。使用几种基因探针，我们还确定了不同气单胞菌物种的临床或环境菌株中存在TTSS，这些物种包括嗜水气单胞菌、维罗纳气单胞菌和豚鼠气单胞菌。通过使用TTSS基因之一（ascV），我们在菌株AH-3中获得了一个明确的插入突变体（AH-3AscV），与野生型菌株相比，该突变体的毒性和毒力有所降低。用携带ascV的质粒载体对突变菌株进行互补，完全能够恢复野生型的毒性和毒力。
