FIG. 4.

Glutathione is required to prevent the extended lag in cells possessing the Kdp system in low-potassium medium. Cells were grown overnight and resuspended in medium as defined in the text. Growth experiments were conducted exactly as described. (a) Cells of Frag1 (▴), MJF355 [gshA::Tn10 (kan); ■], Frag5 (kdpABC; ○), and Frag56 [gshA::Tn10 (kan) kdpABC; •] were grown overnight in K_0.2 medium and resuspended in fresh K_0.2 medium, and the growth was monitored. (b) Cells were grown overnight in K₁₀ medium and resuspended in K_0.2 medium, and the growth was monitored (symbols are the same as in panel a). (c) Cells of MJF355 were grown overnight in K_0.2 medium in either the presence (□) or absence (■, ▵) of 1 mM glutathione. The overnight cultures were then resuspended in K_0.2 medium in either the presence (▵) or absence (□, ■) of 1 mM glutathione, and the growth was monitored.