FIG. 3.

β-Galactosidase activity encoded by splB-lacZ fusions in spores of B. subtilis strains carrying either multicopy plasmid pMK3 (open bars) or the splA gene carried on plasmid pMK3 (plasmid pWN489; hatched bars). Values of β-galactosidase activity were normalized to strain WN491 carrying the wild-type Δ2 splB-lacZ fusion at amyE, a complete deletion of the natural splAB operon, and vector plasmid pMK3. Specific β-galactosidase activity of strain WN491 was 341.5 ± 13.2 U. Data are reported as averages ± standard deviation for two independent duplicate determinations.