Construction of an extended range whole‐cell tetracycline biosensor by use of the tet (M) resistance gene

An extended range whole‐cell tetracycline biosensor strain was constructed by insertion of the tet (M) gene, encoding tetracycline resistance by ribosomal protection, into plasmid pTGFP2, which contains a transcriptional fusion between a tetracycline regulated promoter and the green fluorescent protein gene. Tetracycline, oxytetracycline, chlortetracycline and minocycline all effectively induced the resulting Escherichia coli MC4100/pTGM biosensor and similar dose–response characteristics were recorded by flow cytometry for all four compounds. The novel tetracycline biosensor was responsive to drug concentrations ranging from below 5 ng ml −1 to 16 μg ml −1 , which represents a significant improvement of the original version.