Noninvasive monitoring of environmental toxicity through green fluorescent protein expressing Escherichia coli

The facile and rapid monitoring of the cellular response to environmental stresses is crucial for understanding the effects of environmental toxicity in living organisms. The overall cell growth can be examined to find a simple monitoring system. Green fluorescent protein (GFP) is advantageous when used as a reporter protein of the cellular stress responses in Escherichia coli because it allows the non-invasive monitoring of GFP in vivo without affecting the cell metabolism. We compared the environmental toxicities of chemical pollutants using GFP expressing E. coli for easy monitoring by incubation in various concentrations of harmful chemicals (ethanol, phenol, para-formaldehyde, paraben, and triclosan). The results showed that all the chemical pollutants act on cell growth and the cell metabolism according to the measured cell density and fluorescent intensity of GFP. In addition, from comparative analysis for quantification, the concentration of unknown ethanol toxicity, which was not determined at that concentration, could be deduced. In conclusion, the degree of toxicity for each chemical pollutant could be estimated or evaluated. This system will be useful for monitoring the toxicity of chemical pollutants in a non-invasive monitoring system.