Data processing by the chemotaxis machinery of Escherichia coli

Abstract

THE chemotactic behaviour of Escherichia coli provides a useful model for study of the molecular basis of a simple stimulus-response sequence¹. Chemical stimuli are detected by specific receptors² which in turn alter the rotation of the flagella³ to elicit movement towards attractants or away from repellents. About twenty types of chemoreceptors have been identified in E. coli^4–6, suggesting that a communication system transmits sensory data from the receptors to the flagella, and that signals from different receptors converge either before or on reaching the flagella. I have attempted to dissect this system by isolating and examining nonchemotactic (che) mutants of the type first described in E. coli by Armstrong et al.⁷. In this report I summarise the properties of che mutants and derive a model of the chemotaxis machinery based on this genetic analysis.