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Construct Maps

Model of BBa_K389015

Fig. 1: Main construct of acetosyringone inducible luciferase expression system containing constitutive expression of the two component receptor system (virA+virG).

Model of BBa_K389016

Fig. 2: Control construct of acetosyringone inducible RFP read out system.

Model of BBa_K389014

Fig. 3: Screening construct of acetosyringone inducible kanamycin resistance read out system.

Fitting the data

As seen in the fig. 1 - 3 the models for the application of the used VirA/G signaling system is quite complex. Due to the fact that there were no further details to interactions between the components of this receptor system in the literature which are helpful for modelling and a determination of these parameters would be too time-consuming we decided to fit the vir promoter activity to different concentrations of the natural inducer of the VirA/G signaling system, acetosyringone. As the promoter activity is not directly accessible we decided to measure it by using a reporter gene.

Promoter activity is normally measured in polymerases per second (PoPS). To correlate the concentration of a reporter gene with PoPS a synthesis rate for the reporter gene has to be measured to see how many molecules are produced by one cell in a certain time (| Canton and Labno, 2004). This relation can be described as

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with the amount of product P, the cell count X and the specific production rate of product molecules per cell and time qP. To determine the PoPS exactly from the specific production rate there is more information needed like the decay of the reporter molecule, the stability of the reporter gene mRNA, the effectivity of the reporter gene's RBS and many more. So we assumed that these parameters do not change in the time of our measurement. In addition we assumed after | Canton and Labno, 2004 that