FIGURE 9.

Growth analysis of cells overexpressing oatA under sulfur-limiting and exogenously provided cysteine conditions. The oatA⁺ allele was cloned into a complementation vector and introduced into an oatA::kan⁺ background. The same empty vector was introduced into strains as indicated in symbol legends. Cells from overnight cultures (lysogeny broth) were washed twice and grown on minimal medium with glycerol (22 mM), chloramphenicol, and transcription of plasmids was induced by addition of arabinose (1 mM). Growth of strains was assessed under sulfate-limiting conditions (MgCl₂ added in lieu of MgSO₄, 1 mM) and curves were obtained using a microplate reader (BioTek Instruments). Error bars represent standard deviation and each experiment was completed in three independent experiments with strains in triplicate, with a representative graph shown. (A) Growth of strains under sulfur limiting conditions (MgCl₂ added in lieu of MgSO₄, 1 mM). (B) Growth after addition of exogenous L-Cys (200 μM), (C) L-Met (300 μM), and (D) oxidized glutathione (2.5 mM). Symbols in (B) apply to data in (A–D).