Fig. 6.

Continuous and near linear accumulation of external 2OG without a functional KgtP. E. coli (Ec) kgtP mutant strain FG1602 (A) and Salmonella serovar Typhimurium (Se) wild-type strain SK2633 (B) were cultured in NH₄Cl-glycerol medium. 2OG concentrations in medium were assayed from immediately after inoculation through the late exponential phase of growth. Internal 2OG concentrations were also measured at different cell densities. The E. coli wild-type external 2OG data in panel A are from Fig. 2A for comparison. (C) kgtP is transcribed in E. coli but silent in Salmonella serovar Typhimurium. The three strains were cultured identically to those described in panels A and B, cells were collected at an OD₆₀₀ of ∼0.4, and RNA was extracted. cDNA was reverse transcribed and subjected to PCR detection of kgtP expression. Genomic DNA extracted from colonies served as the control template for PCR.