FIG. 8.

Effect of a point mutation in the cssRS promoter on its induction by secretion stress. The transcriptional PcssRS-lacZ fusion in B. subtilis 168 xylR::xylR-amyL PcssRS::pDN221 (DN225), which contains a xylose-inducible amyL gene, was used to determine the time courses of cssRS promoter activity in cells grown at 37°C in TY medium with 1% xylose (open rectangles) or without xylose (solid rectangles). In parallel, the transcriptional P*cssRS-lacZ fusion in B. subtilis 168 xylR::xylR-amyL PcssRS::pDN222 (DN228) was grown in the presence (open ellipses) or absence (solid ellipses) of 1% xylose. β-Galactosidase activities were measured in nanomoles per minute per OD₆₀₀ unit. Zero time (t = 0) indicates the transition point between the exponential and postexponential growth phases.