Cai Jie, Salmon Kirsty, DuBow Michael S
Microbiology (Reading). 1998 Oct;144 ( Pt 10):2705-2729. doi: 10.1099/00221287-144-10-2705.
Operons encoding homologous arsenic-resistance determinants (ars) have been discovered in bacterial plasmids from Gram-positive and Gram-negative organisms, as well as in the Escherichia coli chromosome. However, evidence for this arsenic-resistance determinant in the medically and environmentally important bacterial species Pseudomonas aeruginosa is conflicting. Here the identification of a P. aeruginosa chromosomal ars operon homologue via cloning and complementation of an E. coli ars mutant is reported. The P. aeruginosa chromosomal ars operon contains three potential ORFs encoding proteins with significant sequence similarity to those encoded by the arsR, arsB and arsC genes of the plasmid-based and E. coli chromosomal ars operons. The cloned P. aeruginosa chromosomal ars operon confers augmented resistance to arsenic and antimony oxyanions in an E. coli arsB mutant and in wild-type P. aeruginosa. Expression of the operon was induced by arsenite at the mRNA level. DNA sequences homologous with this operon were detected in some, but not all, species of the genus Pseudomonas, suggesting that its conservation follows their taxonomic-based evolution.
编码同源抗砷决定簇（ars）的操纵子已在革兰氏阳性菌和革兰氏阴性菌的细菌质粒以及大肠杆菌染色体中被发现。然而，在医学和环境中具有重要意义的铜绿假单胞菌中，这种抗砷决定簇的证据存在矛盾。本文报道了通过克隆和互补大肠杆菌ars突变体来鉴定铜绿假单胞菌染色体ars操纵子同源物。铜绿假单胞菌染色体ars操纵子包含三个潜在的开放阅读框，其编码的蛋白质与基于质粒和大肠杆菌染色体ars操纵子的arsR、arsB和arsC基因编码的蛋白质具有显著的序列相似性。克隆的铜绿假单胞菌染色体ars操纵子赋予大肠杆菌arsB突变体和野生型铜绿假单胞菌对砷和锑氧阴离子增强的抗性。该操纵子的表达在mRNA水平上由亚砷酸盐诱导。在一些但并非所有的假单胞菌属物种中检测到与该操纵子同源的DNA序列，这表明其保守性遵循基于分类学的进化。
