FIG. 8.

Time courses for uptake of [³H]TMG into B. subtilis cells expressing chromosomally encoded L. brevis galP gene. Cell cultures used either lacked (A) or possessed (B) a functional B. subtilis ptsK gene. Plasmid pMK4 with the inserted L. brevis ptsH genes encoding wild-type HPr (□), S46A HPr (○), or S46D HPr (■) is also present. The control strain (●) did not contain plasmid pMK4. Conditions were as described under Materials and Methods, with a [³H]TMG concentration of 20 μM. (A) Cells were grown in LB with 1% glucose, and 10 mM glucose and 20 mM arginine were added as energy sources for the transport studies. (B) Cells were grown in LB with 1% gluconate, and 10 mM gluconate and 20 mM arginine were added for the transport experiment as described under Materials and Methods. The differences between panels A and B reflect the conditions used rather than strain differences. Thus, when the two experiments (A and B) were conducted with both wild-type and ptsK mutant strains, the results were essentially the same for each of the two growth conditions.