2007 Volume 56 Issue 12 Pages 993-1003
It is possible to use bacterial living cells as biosensor elements by applying their chemical-sensing systems. A link between the sensing systems and reporter systems, such as firefly luciferase by genetic manipulation, enables an improvement of the specificity and sensitivity to chemicals in such biosensors. We successfully established whole-cell biosensors composed of photosynthetic bacteria as a host strain and their carotenoid synthetic genes as a reporter. In the presence of target chemicals, the color of biosensors changed from yellow to red based on carotenoid conversion in the host cells; this change is obvious by the naked eye without any equipments or additional reagents. In this paper, we introduce procedures to construct carotenoid-based biosensors, the detection of dimethyl sulfide or arsenite by the color change due to carotenoid conversion, and an approach to obtain an obvious color change in a reporter event using green mutants as a host strain of biosensors.
