One may easily determine the responsiveness of a fluoride riboswitch to fluoride by simply cloning the riboswitch of interest into the operon using the Gibson homology overhangs included in the sequence of the part. To determine the responsiveness of the riboswitch of interest, one may plate the operon containing Δ-crcB (fluoride efflux pump) E. coli onto agar plates with varying levels of fluoride. This technique can be applied to test at which levels of fluoride other riboswitches are most responsive.
Additionally, our operon is valuable in qualitatively measuring amounts of fluoride in water. To qualitatively determine the amount of fluoride in a water sample, one may make agar plates with the water being tested and grow Δ-crcB E. coli containing BBa_K2843000 with the B. cereus riboswitch. This allows for a relatively simple and replicable device to qualitatively measure fluoride levels in water.
In the images below you are able to see growth of Δ-crcB E. coli increase with increasing levels of fluoride, demonstrating its value as a device for qualitative measurement of excess fluoride in water.