A MODEL OF EXCITATION AND ADAPTATION IN BACTERIAL CHEMOTAXIS

Bacterial chemotaxis is widely studied because of its accessibility an d because it incorporates processes that are important in a number of sensory systems: signal transduction, excitation, adaptation, and a ch ange in behavior, all in response to stimuli. Quantitative data on the change in behavior are available for this system, and the major bioch emical steps in the signal transduction/processing pathway have been i dentified. We have incorporated recent biochemical data into a mathema tical model that can reproduce many of the major features of the intra cellular response, including the change in the level of chemotactic pr oteins to step and ramp stimuli such as those used in experimental pro tocols. The interaction of the chemotactic proteins with the motor is not modeled, but we can estimate the degree of cooperativity needed to produce the observed gain under the assumption that the chemotactic p roteins interact directly with the motor proteins.