Chemotaxis of Salmonella typhimurium toward citrate

Salmonella, but not Escherichia coli, was attracted to citrate, a distinction that is understandable in view of the inability of E. coli to transport tricarboxylic acids. The Salmonella response to citrate and to two previously described attractants, aspartate and malate, was mutually noncompetitive. Citrate taxis different from citrate uptake in that it did not require Na+, was constitutive, and was not repressible by glucose.