TABLE 3.

Dynamics of the wild-type and mutated spaS promoters^a

Construct	Mean fluorescence (%) withb:
	No supernatant	0.1% (vol/vol) supernatant	0.2% (vol/vol) supernatant	0.5% (vol/vol) supernatantc
Empty vector	0	0	0	0
PspaS	0.5	14.5	42.8	57.3
PspaSmut	1.2	65.0	100	98.4

^aCultures of B. subtilis NZ8900 harboring pNZ8902 (empty plasmid), pNZ8908 (P_spaSmut-gfp), or pNZ8907 (P_spaS-gfp) were grown to an OD₆₀₀ of 1, and the supernatant of an overnight culture of subtilin-producing strain ATCC 6633 was added at the concentrations indicated. After 2 h, cells were collected for flow cytometric analyses.

^bEach value is the percentage of the mean fluorescence of the population compared to the maximal observed fluorescence. This value was calculated as follows: the mean fluorescence of 20,000 cells (calculated using WinMDI [http://facs.scripps.edu/software.html]) was divided by the observed mean fluorescence after induction with 0.2% (vol/vol) supernatant of B. subtilis ATCC 6633 of the construct with the P_spaSmut promoter, normalized to the empty vector, and multiplied by 100%. The results of a representative experiment are shown.

^cNo significant increase in fluorescence intensity was observed upon induction with more than 0.5% (vol/vol) culture supernatant of B. subtilis ATCC 6633.