FIG. 3.

Growth and ³³P_i uptake. (A) Growth curve of pitA mutant strain K10 (○), pitA pstS double-mutant CE1485 (□), and the pseudorevertant CE1487 (▵). Cells were grown overnight in Luria broth supplemented with G3P, pelleted, and resuspended in HEPES-buffered synthetic medium (25) supplemented with 0.5% glucose and 660 μM K₂HPO₄. Growth was monitored for 7 h. (B) Uptake of ³³P_i by cells of strains K10 (○), CE1485 (□), and CE1487 (▵). Cells were grown in Luria broth supplemented with 20 mM glucose and 1 mM G3P to an optical density at 660 nm (OD₆₆₀) of approximately 0.9, washed, and resuspended in a solution of 20 mM potassium piperazine-N,N′-bis(2-ethanesulfonate) (PIPES) (pH 7.0)–10 mM MgSO₄. These cells were stored on ice, and, within 2 h, transport assays were performed at 30°C with 50 μM ³³P-labeled potassium phosphate as described previously (27). The experiments were repeated three times with essentially the same results, and data from a representative experiment are shown.