Real-Time Multiplexed Signal Transduction in Microbial Environmental Sensors

Biologically relevant environmental monitoring can be achieved using the genetic responses of microbes to environment conditions as sensors, particularly the specific and generalized responses to toxicity. The generalized toxicity response may be especially improtant when prior knowledge of the type of toxin in unavailable. Real-time transduction of the genetic responses is most commonly provided by coupling a gene encoding a bioluminescent protein to the system. However, while this works well under controlled laboratory conditions, the information content of a single luminescent signal generally is insufficient to compensate for the complexity of living systems. We propose development of a system based on multiplexing by wavelength to increase the information content of the signal transduction process. Our research has shown that the color of light emitted by beetle luciferases can be controlled by changing less than 1% of their primary structures. This unique situation should allow incorporation of functionally equivalent but distinguishable signal generators into a single sensor, thus granting internal control of the sensor response. The product of this work will be a platform design for a signal transduction system to provide reliable and robust performance of microbial sensors. The general and fundamental nature of this design will make it widely portable into different sensor configurations. Anticipated Benefits: The multiplexing system has novel and important potential applications in several markets, including "real time" detection of toxics in environmental samples. Advantages of this technology versus current "rapid" environmental diagnostics include increased sensitivity, specificity, and the potential to develop tests for defined groups of contaminants in a single biosensor.