Construction and behavior of strains with mutations in two chemotaxis genes.

Double mutants have been constructed by transducing each of the six che genes from the main che gene cluster into the cheC mutant with reversed behavior. The behavioral properties of these double-mutant strains were examined. The results are interpreted in terms of a model based on the cheC gene product being the component of the flagellar basal body that generates tumbling or smooth swimming in response to changes in the level of the response regulator. The properties of the double mutants can then be explained in ways which provide further understanding of the bacterial sensing system.