發展偵測環境異生化合物之靈菌生物感測器

A Serratia marcescens Derived Biosensor for Detection of Environmental Xenobiotic Compounds

We have previously identified a pair of bacterial two-component system RssA-RssB involved in regulation of Serratia marcescens swarming. Further studies showed that RssA RssB signaling is growth phase dependent, being inactivated at early logarithmic phase for a period of about 30 min. During this period, expression of the flagellar master regulatory operonflhDCSm whose transcriptional regulation is under direct control of RssB is increased due to derepression. In this article, the environmental toxic compounds, including benzene, ethyl benzene, toluene, and xylene (BTEX) were found to show clearly negative effect on S. marcescens CH-1 swarming. The expression of flhDCSm and synthesis of flagellum were decreased accordingly. Whether the BETX compounds at non-lethal concentration can affect the signaling status of RssA-RssB andsubsequently repress the expression level of flhDCSm was evaluated. Using the S. marcescens CH- (pflhDCsm::luxCDABE), the biosensor strain grown to early logarithmic phase as thereporter strain, results showed that increase of flhDCSm expression level was inhibited in the presence of BTEX compounds in a dose-dependent manner. Subsequent detection of contaminated water samples taken from a industry waste water showed clear reduction of light emission in comparison with the uncontaminated waters. Thus this strain bears the potential of being developed to be a biosensorstrain for use in a upset early warning device (UEWD) for rapid detection of contaminated water. 本研究先前由靈菌找出一二元傳訊系統RssA-RssB，flhDCSm為其下游調控因子。在細菌早期對數生長期時，其活性受抑制。本研究探討flhDCSm起動子對於環境荷爾蒙是否有反應。研究中構築含pflhDCsm::luxCDABE質體之靈菌作為反應指示。研究結果顯示此生物感應器可有效偵測BTEX等環境荷爾蒙之存在。

We have previously identified a pair of bacterial two-component system RssA-RssB involved in regulation of Serratia marcescens swarming. Further studies showed that RssA RssB signaling is growth phase dependent, being inactivated at early logarithmic phase for a period of about 30 min. During this period, expression of the flagellar master regulatory operonflhDCSm whose transcriptional regulation is under direct control of RssB is increased due to derepression. In this article, the environmental toxic compounds, including benzene, ethyl benzene, toluene, and xylene (BTEX) were found to show clearly negative effect on S. marcescens CH-1 swarming. The expression of flhDCSm and synthesis of flagellum were decreased accordingly. Whether the BETX compounds at non-lethal concentration can affect the signaling status of RssA-RssB andsubsequently repress the expression level of flhDCSm was evaluated. Using the S. marcescens CH- (pflhDCsm::luxCDABE), the biosensor strain grown to early logarithmic phase as thereporter strain, results showed that increase of flhDCSm expression level was inhibited in the presence of BTEX compounds in a dose-dependent manner. Subsequent detection of contaminated water samples taken from a industry waste water showed clear reduction of light emission in comparison with the uncontaminated waters. Thus this strain bears the potential of being developed to be a biosensorstrain for use in a upset early warning device (UEWD) for rapid detection of contaminated water.