Tokyo/Requirements

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Abstract　　Concept & Model　　Requirements　　Genetic_circuit　　Works　　About_our_team

What is necessary for "stable coexistence"?

The most important and underlying point of our model is that the system is stable against environmental changes when two types of individuals coexist, called "stable coexistence." Our project have aimed at this "stable coexistence" but not dynamic equilibrium such as chemical ones.

To achieve this “stable coexistence", our model requires
1. bistability at two distinct states in a single cell
2. cell-cell communication by quarum sensing

Fig.1: Bistablity
Cells with the same gene take either of two states, A (worker, red) or B (idler, green) stably and become unstable in between.

1. Bistability

~ at an individual level ~

For "stable coexistence" in our model, two types of cells should coexist stably. Therefore, cells with THE SAME GENE SET need to take either of TWO STATES, A (Worker) or B (Idler) in our project as shown in Fig. 1. In order to distinguish from dynamic stability, "stable coexistence" must be achieved by two distinct states inconvertible each other.

2. Cell-cell communication

When this stable coexistence is disrupted, by removing all the A type for example, these individual cells sense the change. Their states A or B become unstable as if cells became upset - INDIVIDUAL STATES ARE UNSTABLE ⇒ They are COLLECTIVELY UNSTABLE. Then some of them changed their states while the others do not. As a result, at a certain ratio of A and B again, the whole system comes back to a stable states. Here the cells are COLLECTIVELY STABLE ⇒ INDIVIDUALS ARE STABLE under this stable coexistence.

Fig.2: Cell-cell communication
Intercellular interaction is done by communication molecule AHL. When enough AHL is produced by the workers, the idlers are stable; however, if it is not ~ communication being interrupted, ~ they become unstable. Thus, cells can sense the surrounding cell types.