The development and application of bacterial biosensors for toxicological analysis
A group of inducible sensors were characterised under a standard protocol in order to comprehensively compare them. Subsequently, the toxicity of a series of mercury anions was investigated using the suite of inducible sensors and chemical analysis. Next, the response of the inducible sensors was tested against a number of metal ions in order to determine their capacity to induce the biosensors, and against a constitutively marked biosensor to measure the toxicity of the individual metal ions. These bioluminescent data were used to determine the presence of quantitative structural activity relationships (QSARs) between the metal ions and the transcriptional switches of the sensor. Homology was identified but further characterisation is required. Finally, an assessment of a number of environmental samples was carried out using a combination of chemical analysis, toxicity-based and inducible biosensors. Soil characteristics influenced the bioavailable fraction of mercury in the extracts under investigation and the biosensors had the capacity to report on the bioavailable fraction present. Whilst the sensors could predict the bioavailable fraction of mercury in aqueous systems, it is clear in order to exploit their potential they must be used in combination with other sensors and in conjunction with chemical analysis techniques. Biosensor technology has progressed significantly in the past decade, but while there is clear evidence of their construction, there is a lack of environmental application.