Model

We adopted both deterministic ODE-based and stochastic Gillespie-based methods to optimize our parameters through repeated comparison between these two, and ultimately, to simulate the process of our bacteria detecting the psychoactive ingredient Δ9-THC as accurately as possible.

Moreover, the deterministic ODE-based model for Degradation Module, was constructed and integrated into the Detection system since degradation of Δ9-THC starts once detection pathway is activated, and detection pathway is inactivated when Δ9-THC is low because of degradation. And we managed to achieve great coherence between the 2 modules.

We built a reaction-diffusion model incorporating spatial aspects to simulate and furthermore predict the process of intestinal arabinose diffusion and CcdB expression for the arabinose-induced pathway, and an ODE-based modified GFP model to fit and obtain the RBS efficiency and to estimate MazF threshold for the MazEF-mediated pathway based on data gained from experiment.

Quorum sensing is a process of cell-cell communication that allows bacteria to share information about cell density and adjust gene expression accordingly. Quorum sensing bacteria produce and release chemical signal molecules called autoinducers that increase in concentration as a function of cell density. Here, E.coli uses acylated homoserine lactones (AHL) as autoinducers.

Throughout the modelling process, we are able to validate the feasibility of our whole project design, and further achieve an excellent interaction with biological experiment and mathematical model.