Fig. 3

NAD⁺-dependent SI dehydrogenase activity and β-galactosidase activities of strains of B. subtilis. a NAD⁺-dependent SI dehydrogenase assays. Strains 168 (lanes 1–6), BFS3018 (lanes 7–12), CM101 ((ΔyisR, lanes 13 and 18), and CM102 (ΔiolQ, lanes 19–24) were inoculated into S6 medium containing 0.5% casamino acid and 0.005% tryptophan (lanes 1, 7, and 13) cultured to an OD₆₀₀ of 1.0. As indicated, the culture media were supplemented with the carbon sources (10 mM each) MI (lanes 2, 8, 14, and 20), SI (lanes 3, 9, 15, and 21), glucose (lane 4, 10, 16, and 22), glucose plus MI (lanes 5, 11, 17, and 23), and glucose plus SI (lane 6, 12, 18, and 24). Values are means + SD obtained from three independent assays. b Organization of the iolX locus in BFS3018. c β-Galactosidase assays. Strain BFS3018 was inoculated into S6 medium containing 0.5% casamino acid and 0.005% tryptophan (lane 1) cultured to an OD₆₀₀ of 0.5. As indicated, the culture media were supplemented with the carbon sources (10 mM each) glucose (lane 2), MI (lane 3), SI (lane 4), and glucose and SI (lane 5). Values are means + SD obtained from three independent assays