Discussion

iGEM UT-Tokyo

Our experiments demonstrated that cheZ-mediated motility regulation is possible and Asp regulates E.coli migration. Evaluation of Asp-production system is incomplete due to limited means to quantitate Asp, but our simulation demonstrated that an increase in bacterial concentration can be achieved using our system and that this increase in concentration will raise the efficiency of bioremediation.

Why we chose to work with SOS promoters

As described in the project overview, our system works by combining and adding the adequate induction apparatus, including receptors, transcription factors and promoters. The SOS response is a rapid reaction in microorganisms induced by DNA damage. We used SOS promoters to control the induction of our system as proof of principle that components of our system are functional.

Transcription by SOS promoters is negatively regulated by a native repressor of E.coli, LexA. The induction intensity of a SOS promoter is considered to be determined by the affinity of LexA. In our research we use sulAp because it is usually strongly repressed but is efficiently induced by UV irradiation. The measurement of sulAp by dual luciferase assay is described in the Results page in detail.

The selection of other pairs of receptors and substrates allows you to make it possible to improve existing and new bioremediation systems. Our results concerning the UV switch also offer reliable data to other projects involving bioremediation.