FIG. 3.

Inducers of alkB1 and alkB2 genes. Strains RR1B1 and RR1B2 were grown in minimal salts M9 medium containing Tween 80 (0.3%, vol/vol) as the carbon source in the absence or presence of different alkanes (C₈ to C₂₄), alcohols (C₁₄-OH, C₁₆-OH, and C₁₈-OH), aldehydes (dodecanal, C₁₂-HO), and fatty acids (myristic acid, C₁₄-OOH). When cultures reached a turbidity of 2.0 (late exponential phase), the levels of β-galactosidase were measured. Liquid hydrocarbons were added at 1% (vol/vol), and solid hydrocarbons were added at 1% (wt/vol). Dotted bars correspond to the values obtained for strain RR1B1 (PalkB1::lacZ transcriptional fusion), and gray bars correspond to those for RR1B2 (PalkB2::lacZ transcriptional fusion).