FIG. 4.

Temperature-dependent expression of SigB-controlled ctc-lacZ (A) and gsiB-gfp (B) fusions. (A) The B. subtilis ctc-lacZ fusion strain BSA46 was grown in SMM at the indicated temperatures either in the absence (filled bars) or in the presence (open bars) of 1 mM glycine betaine. Samples were removed for β-galactosidase assays during exponential growth (OD at 578 nm, 0.5). β-Galactosidase activities are expressed in Miller units (MU). (B) The B. subtilis gsiB-gfp fusion strain BSM269 was grown in SMM at the indicated temperatures, and samples were removed for phase-contrast and fluorescence microscopy during exponential growth (OD at 540 nm, 1.0). Left and right panels display phase-contrast and fluorescence images, respectively, of the same cells.