9-Nitrobenzo[b]quinolizinium as a fluorogenic probe for the detection of nitroreductase in vitro and in Escherichia coli

The non-fluorescent 9-nitrobenzo[b]quinolizinium is readily reduced by nitroreductase to a fluorescent reaction product. The resulting light-up effect enables the selective detection of nitro-reductase activity in vitro and in Escherichia coli bacterial cultures.