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Works top  0.Hybrid promoter  1.Formulation  2.Assay1  3.Simulation  4.Assay2  5.Future works

Activation check by cell-produced AHL   Expression level check on promoters + plasmid sets of A and B sides

Purpose of this assay ()

Parameters for the equations in Formulation have been experimentally determined in Assay1. Analysing the result, the following experiments were turned out to be necessary.

Activation check by cell-produced AHL

Fig.1 By culturing with AHL producing cells, whether the lux lac hybrid promoter was activated without externally adding AHL. Regardless of the copy numbers of the luxI encoding plasmids, the hybrid promoter was activated.


To check if worker E. coli (Sender) can produce enough AHL for our model to work by using different copy numbers of plasmids.

Result & Conclusion

Not only high copy number plasmid pSB1, also low copy number plasmid pSB4 and pBR produced enough AHL to activate the LacI hybrid promoter in other cells. Especially, pBR remarkably produced AHL in the present experiment.

⇒see more details

Expression level check on promoters + plasmid sets of A and B sides


Fig.2 Expression levels of the both sides were compared. As to the A side, RFP was substituted with GFP.

To test and compare the gene expression level of each side, A and B. Since the cell type - A or B - is detected based on the fluorescence, its activity should be measured and standardized beforehand. Here we used the same fluorescent protein GFP on the both promoter + plasmid sets actually used in our model, where A side consists of Lambda cI-regulated promoter, and B side the lux lac hybrid promoter.

Result & Conclusion

Two plasmid sets, A4Δp+pc1-GFP and A4 hybrid+GFP PBR322TetR (+)AHL, shows almost the same fluorescence of GFP, indicating that expression levels of both sets are almost the same though the latter is a bit smaller.

⇒see more details