FIG. 2.

Regulation of ΔaraGFB::[Φ(pspA-lacZY)] and ΔaraGFB::[Φ(yopH-lacZY)] fusions. (A) Φ(pspA-lacZY) expression. Plasmid pVLT33 (−), pAJD509 (yscC), or pAJD554 (ysaC) encoding the indicated genes expressed from the tac promoter were transferred into a pYV-negative derivative of strain AJD957. Strains were grown exactly as described previously (11). (B) Φ(yopH-lacZ) expression. Strain AJD1022 was grown at 26°C or 37°C in low- or high-calcium media as described previously (6). β-Galactosidase activities were determined as described previously (14) and are expressed in Miller units (each value is the average of measurements from three independent cultures). Sp. Act. = specific activity.