Aerobic

Part: BBa_I13602

Microaerobic

Part: BBa_K561000

Pvgb — RBS (medium) + YFP (Part: BBa_I15017) — RBS (strong)+tetR+double terminator (Part: BBa_P0440)

Anaerobic

Part: BBa_K561002

fdhF— RBS (strong) +RFP (Part: BBa_K093005)—RBS (strong)+tetR+double terminator (Part: BBa_P0440)

Our rainbofilm was constructed with three different sub-devices, whose expressions are controlled by three different promoters: Ptet, Pvgb andPfdhF. Under aerobic conditions, Ptet constitutively regulates expression of CFP. Under micro-aerobic and anaerobic conditions, Pvgb and PfdhF work respectively and lead to the expression of tetR, which represses Ptet. The repression of Ptet stops the expression of CFP. Under micro-aerobic conditions, its promoter, Pvgb, has its highest expression, while under anaerobic conditions, PfdhF contributes to the expression of RFP.

From the surface to the bottom, the bacteria maintain different physiological states in a layered fashion. These varied layers can be characterized by gradients in the concentrations of oxygen. We used oxygen concentration gradients within the biofilm as signals to induce the expression of different proteins.