Figure 2. Genes involved in sulfate assimilation are crucial for MR-mediated H2S production. (a) Methionine metabolic pathway. A gene name is shown in the corresponding step. (b) Lead acetate assay to determine methionine metabolism-related genes under diverse methionine restricted conditions. (b) Three-dimensional plot demonstrating the effect of gene deletion on hydrogen sulfide production. Hydrogen sulfide levels under 50 mg/L (regular condition) and 5 mg/L (MR condition) of methionine were digitized based on spot darkness. For wild-type and deletion mutants, the x-axis indicates the difference between MR-condition and regular-condition hydrogen sulfide levels and the y- and z-axes indicate the difference between the deletion mutant and wild-type hydrogen sulfide levels under regular and MR conditions, respectively. Spot color shows low (red) to high (blue) z-axis values.