In many natural and synthetic biochemical systems, information is exchanged from one component to another via a chemical signal. For example, quorum sensing in bacteria colonies exploits the exchange of autoinducers in order to establish consensus. While it is highly desirable to coordinate via such information exchange, it comes at the cost of producing information carrying molecules. In complex biochemical systems, these molecules may interact chemically or physically with other components controlling the emitting system or with other biochemical systems in the environment. A basic question is therefore what kinds of constraints must be imposed on the communication mechanism such that normal regulation still functions; that is, the systems can coexist.
In this talk, I will formalise this problem in the context of systems modelled via stochastic chemical reaction systems. By developing a new coexistence constraint on communication imposed by the environment, I will then establish information theoretic limits on the quantity of information that can be sent. The constraint provides a means of abstracting how complex biological control mechanisms interact with the communication mechanism. Under the coexistence constraint, the number of bits of information that can be sent scales sublinearly with the number of transmitted symbols. This implies that significantly less information can be transmitted than in classical communication systems.
