FIG. 3.

(A) Effect of exogenous arginine on the uptake of arginine, ornithine, and lysine in a pair of isogenic strains of P. aeruginosa, PAO4447 (wild type for aot) (circles) and PAO4450 (aotJQMOP deletion) (triangles). Cultures grown in minimal medium P with either arginine (solid symbols) or glutamate (open symbols) as the sole source of carbon and nitrogen were harvested in the early log phase and used for l-arginine transport assays, as described in Materials and Methods. (B) Competition tests of arginine uptake in P. aeruginosa. The wild-type strain, PAO1, was grown in minimal medium P with arginine as the sole source of carbon and nitrogen, and arginine transport assays were done with different molar ratios of cold arginine (solid bars), ornithine (shaded bars), and lysine (open bars) to [³H]arginine as indicated.