Kim Juhyun, Jeon Che Ok, Park Woojun
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Korea.
J Microbiol Biotechnol. 2007 Oct;17(10):1727-32.
Phenylacetic acid (PAA) is produced by many bacteria as an antifungal agent and also appears to be an environmentally toxic chemical. The object of this study was to detect PAA using Pseudomonas putida harboring a reporter plasmid that has a PAA-inducible promoter fused to a green fluorescent protein (GFP) gene. Pseudomonas putida KT2440 was used to construct a green fluorescent protein-based reporter fusion using the paaA promoter region to detect the presence of PAA. The reporter strain exhibited a high level of gfp expression in minimal medium containing PAA; however, the level of GFP expression diminished when glucose was added to the medium, whereas other carbon sources, such as succinate and pyruvate, showed no catabolic repression. Interestingly, overexpression of a paaF gene encoding PAACoA ligase minimized catabolic repression. The reporter strain could also successfully detect PAA produced by other PAA-producing bacteria. This GFP-based bioreporter provides a useful tool for detecting bacteria producing PAA.
苯乙酸（PAA）由许多细菌作为抗真菌剂产生，并且似乎也是一种对环境有毒的化学物质。本研究的目的是使用携带报告质粒的恶臭假单胞菌来检测PAA，该报告质粒具有与绿色荧光蛋白（GFP）基因融合的PAA诱导型启动子。恶臭假单胞菌KT2440被用于构建基于绿色荧光蛋白的报告融合体，使用paaA启动子区域来检测PAA的存在。报告菌株在含有PAA的基本培养基中表现出高水平的gfp表达；然而，当向培养基中添加葡萄糖时，GFP表达水平降低，而其他碳源，如琥珀酸盐和丙酮酸，则没有分解代谢阻遏作用。有趣的是，编码PAACoA连接酶的paaF基因的过表达使分解代谢阻遏作用最小化。报告菌株还可以成功检测由其他产生PAA的细菌产生的PAA。这种基于GFP的生物报告器为检测产生PAA的细菌提供了一种有用的工具。
