FIG. 1.

The importance of glutathione in protection against methylglyoxal. Cells were grown overnight in K₁₀ medium. After outgrowth into exponential phase, cells were resuspended in either fresh prewarmed K_0.2 buffer or medium as defined in the text. Cell viability, pHi, and methylglyoxal disappearance measurements were conducted exactly as described previously (9–11). (a) pHi measurements in strains Frag5 (kdpABC [•, ○]) and Frag56 [gshA::Tn10 (kan) kdpABC; ■, □] in buffer supplemented with (closed symbols) or without (open symbols) 3 mM methylglyoxal at the time indicated by the arrows. (b) Cell viability of strains Frag5 (•) and Frag56 (■) in medium supplemented with 0.7 mM methylglyoxal at time zero. (c) Methylglyoxal disappearance assay (symbols are the same as in panel b).