As discussed in the Project Description some of Erwinia amylovora´s virulence factors depend on the quorum sensing (QS) phenomenon and, in this specific case, the type of AHL used by this phytopathogen is the 3-oxo-C6-HSL. For simplicity they will continue to be named as AHLs along the whole model. Despite the fact that E. amylovora is not a very studied bacteria and therefore its QS either, we were able to simulate its behavior comparing it to the Vibrio fischeri´s one. The main reason is because of its similarities in the gene regulation. V. fischeri works with the LuxR/LuxI regulation while E. amylovora was found to work under a similar system with a highly homologous regulation, EamR/EamI.

REACTIONS

Based on the law of mass action that states that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants, the whole modified ecosystem is represented in the next chemical reaction network

EQUATIONS SYSTEM

PARAMETERS

MATLAB

Based on the law of mass action that states that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants, the whole modified ecosystem is represented in the next chemical reaction network

OPEN PROBLEMS

Through the model we described the E. amylovra's behavior changes caused by the aiiA enzyme insertion. Nevertheless, the project is based on the combination of three enzymes to reach our goal and inhibit the E. amylovra's virulence factors. We are aware that there is more to do, so with a little help from our friends from IONIS Paris, the yhjH enzyme model is now a future project. They helped us to 3D model the yhjH enzyme (shown below) and to take certain conditions under consideration to its proper activity. Thanks to this edition model, the unregulated gene inhibition over a regulated one can be taken as a basis, and together with the 3D simulation, a second model could be achieved.

Ingalls, B. (2013) Modeling of Chemical Reaction Networks & Gene Regulatory Networks. From Mathematical Modeling in Systems Biology(pp. 21-314 ). England: MIT press.

Frederick K. Balagaddé et al. (2008) A synthetic Escherichia coli predator–prey ecosystem, EMBO, 187, pp. 1-26.

James, S. et al. (2000) Luminescence Control in the Marine Bacterium Vibrio fischeri: An Analysis of the Dynamics of lux Regulation., JMB, 296, pp. 1127-1137.