Team:Grenoble/Projet/Design/quorum

The Quorum Sensing

By coupling Toggle Switch with Quorum Sensing genes, the switch in a pathway defines a specific behavior: receiving or sending bacteria.

	If LacI pathway is activated, CinI proteins are expressed providing to the bacteria the ability to release in the medium Quorum Sensing molecules, AHL.
	Whereas if MerR pathway is activated, CinR proteins are expressed in the inner bacteria. Thus, these bacteria will be able to received AHL molecule.

Put together, both bacterial behaviors allow the formation of AHL/CinR complex in the inner receiving bacteria.

We make use of this complex to visualize the boundary between the two different bacterial behavior areas.

Coloration

The two behaviors encounter each other at the boundary. At this location cells emit AHL closely to receivers.

The AHL molecules enter into the receiving cells and bind receptor protein to form a complex which up-regulates the promoter pCin. Thus, the expression of the three Lycopene synthesise enzymes is allowed. These three enzymes (crtB, crtE, crtI) produce the lycopene pigment so we can observe a red stripe at the interface between receiving and senders.

Both of these parts of the genetic network are modelled in the same module. Coupled with the toggle switch module, this model gives us the behavior of quorum sensing production and complexation. From which we can deduce some optimizations for our device.