FIG. 4.

Effect of cysteine and methionine on production of pyochelin and salicylate by 715j and KLF2. Cells were grown in M9-glucose minimal medium (containing 1 mM magnesium sulfate) at 37°C with aeration for 24 h. Medium contained no additions, or an 18-amino-acid mixture (18AA; concentration of each amino acid, 20 μg/ml) with or without cysteine or methionine (100 μg/ml each). Pyochelin and salicylate were extracted from culture supernatants as described above and analyzed by thin-layer chromatography. Lanes 1 to 4, 715j grown in medium with no supplements, 18AA, 18AA plus cysteine, or 18AA plus methionine, respectively; lanes 5 to 8, KLF2 grown in medium with no supplements, 18AA, 18AA plus cysteine, or 18AA plus methionine, respectively. Abbreviations: P, pyochelin (stereoisomers I [migrating as a doublet] and II); S, salicylate.