Chemotaxis mutants of Spirochaeta aurantia

Five Spirochaeta aurantia chemotaxis mutants were isolated. One mutant (the che-101 mutant) never reversed, one (the che-200 mutant) flexed predominantly, two (the che-300 and che-400-1 mutants) exhibited elevated reversal frequencies, and one (the che-400 mutant) exhibited chemotactically unstimulated behavior similar to that of the wild-type strain. The che-101 and che-400 mutants were essentially nonchemotactic, whereas the che-200, che-300, and che-400-1 mutants showed impaired chemotactic responses. Protein methylation in response to attractant addition appeared normal in all of the mutants. Compared with the wild type, all of the mutants exhibited significantly altered membrane potential responses to the attractant xylose.