Formulate Biological Sensory Adaptation

Living organisms are capable to sense and adapt to a wide range of environmental changes, which is essential for their survival in nature. Although numerous molecular circuits have been evolved to accomplish this sensory adaptation function in different organisms, these circuits share intrinsically the same logical construct. Using Escherichia coli cells as model system, we combined theoretical techniques with experiments to formulate biological sensory adaptation. We demonstrated that E. coli cells accurately “remember” the chemical environment by differentiating and encoding external signals into molecular modifications on specific sensory receptors. We also discovered that E. coli cells adjust their chemical sensitivity via tuning the sensory machinery assembly according to the environment. Moreover, by evaluating the energetic cost associated with sensory adaptation, we were able to derive the exponential tradeoff relation between the benefit (adaptation accuracy & adaptation speed) and the cost (energy dissipation). We believe that this set of approaches sketch a general framework for studying various biological regulatory circuits and the obtained benefit-to-cost relations could shed light on the design principles and the evolution of regulatory circuits.