Fig 3.
(A to C) Levels of β-galactosidase from B. subtilis wild-type (A) and ΔσG (B) strains containing a ywjD-lacZ fusion and RT-PCR analysis of ywjD transcription (C). (A and B) B. subtilis strains PERM557 (ywjD-lacZ) (A) and PERM755 (sigGΔ1 ywjD-lacZ) (B) were grown at 37°C in DSM (●). Cell samples were collected in vegetative growth (Veg) and at various times during sporulation and treated with lysozyme, and the extracts were assayed for β-galactosidase as described in Materials and Methods (□). In panel A, the β-galactosidase activity inside lysozyme-resistant forespores (△) was assayed as described in Materials and Methods. The values shown are averages of duplicate independent experiments ± the SD of the β-galactosidase specific activity expressed as Miller units (22). (C) RNA samples (∼1 μg) isolated from a B. subtilis 168 DSM culture at the times indicated were processed for RT-PCR analysis as described in Materials and Methods. The arrowhead shows the size of the expected RT-PCR products. Lanes: M, DNA markers, 1-kb Plus ladder; Veg, logarithmic growth; T0, the time when the slopes of the logarithmic and stationary phases of growth intersected; T1 to T9, times in hours after T0.