Chemotaxis by Pseudomonas aeruginosa

Abstract

Chemotaxis by P. aeruginosa RM46 was studied, and conditions required for chemotaxis were defined, by using the Adler capillary assay technique. Several amino acids, organic acids and glucose were attractants of varying effectiveness for this organism. EDTA was absolutely required for chemotaxis, and Mg was also necessary for a maximum response. Serine taxis was greatest when the chemotaxis medium contained 1.5 .times. 10-5 M EDTA and 0.005 M MgCl2. It was not necessary to include methionine in the chemotaxis medium. The strength of the chemotactic responses to glucose and to citrate was dependent on prior growth of the bacteria on glucose and citrate, respectively. Accumulation in response to serine was inhibited by the addition of succinate, citrate, malate, glucose, pyruvate or methionine to the chemotaxis medium. Inhibition by succinate was not dependent on the concentration of attractant in the capillary. The degree to which glucose and citrate inhibited serine taxis was dependent on the carbon source utilized for growth. Further investigation of this inhibition may provide information about the mechanisms of chemotaxis in P. aeruginosa.