Figure 2.

The bgl operon activities in the wild type and its various genetic backgrounds. Culture preparation, sample collection, and β-galactosidase assays were carried out as in Figure 1 (see Section 4). (A) Diagram showing the lacZ transcriptional reporter for the entire regulatory region of the bgl operon (Pbgl-bglG-lacZ). The region carrying Pbgl and bglG, including both terminators (−205 to + 1127 relative to the bglG transcriptional start site), was fused upstream of the lacZ’s RBS (that is, TTTCACACAGGAAACAGCT) at the lac locus. Strain Bgl⁺ carries an IS5 element oriented in the inverse direction and inserted at −207.5 upstream of the bglG translation start site. For all other strains, the native bgl operon remains unchanged. For both the operon reporter and the native bgl operon, the blue bars represent the Crp binding sites (O_Crp) while the red bars represent the proposed H-NS binding sites (O_HNS). (B) bgl operon activities in cells grown in M63 with glycerol as the primary carbon source. (C) bgl operon activities in cells grown with glycerol and salicin as carbon sources.