Fukumori F, Hirayama H, Takami H, Inoue A, Horikoshi K
DEEPSTAR Group, Japan Marine Science and Technology Center, Yokosuka.
Extremophiles. 1998 Nov;2(4):395-400. doi: 10.1007/s007920050084.
A toluene-resistant variant of Pseudomonas putida KT2442, strain TOL, was isolated after liquid cultivation under xylene followed by toluene for 1 month in each condition. Almost all the populations of the variant strain formed small but readily visible colonies under toluene within 24 h at 30 degrees C. The toluene-resistant strain also showed an increase in resistance to some unrelated antibiotics. Several toluene-sensitive Tn5 mutants have been isolated from the toluene-resistant strain and showed various levels of sensitivity. Most of these mutations did not cause significant changes in antibiotic resistance; however, one of the mutants (TOL-4) was highly susceptible to both organic solvents and various antibiotics, especially beta-lactams. Sequencing analysis revealed that the mutation in TOL-4 had been introduced into a gene that may encode a transporter protein of an efflux system. This efflux system is very similar to one of the multidrug efflux systems of Pseudomonas aeruginosa. These observations indicate that a multidrug efflux system plays a major role in the organic solvent resistance of P. putida TOL. However, several other genes may also be involved.
恶臭假单胞菌KT2442的耐甲苯变体菌株TOL，是在二甲苯和甲苯条件下分别进行1个月的液体培养后分离得到的。在30℃下，该变体菌株的几乎所有菌落在24小时内于甲苯环境中形成了小而清晰可见的菌落。耐甲苯菌株对一些不相关抗生素的抗性也有所增加。已从耐甲苯菌株中分离出几个对甲苯敏感的Tn5突变体，它们表现出不同程度的敏感性。这些突变大多未导致抗生素抗性发生显著变化；然而，其中一个突变体（TOL-4）对有机溶剂和各种抗生素，尤其是β-内酰胺类抗生素高度敏感。测序分析表明，TOL-4中的突变发生在一个可能编码外排系统转运蛋白的基因中。该外排系统与铜绿假单胞菌的一种多药外排系统非常相似。这些观察结果表明，多药外排系统在恶臭假单胞菌TOL的有机溶剂抗性中起主要作用。然而，可能还有其他几个基因也参与其中。
