Figure 3. Analysis of antibiotic production by nagB suppressor mutants. Phenotypes of nagB suppressor mutants originally selected on GlcNAc (1–15; corresponding to SMA1-SMA15) or GlcN (16–20; corresponding to SMG1-SMG5). The parental strain M145 (21) and the nagB mutant (22) were used as controls. Strains were grown on MM agar plates supplemented with mannitol, glucose, GlcN or GlcNAc. Note that the nagB mutant failed to grow on MM supplemented with either aminosugar. Both front and reverse (inserts) of the agar plates are shown.