Table 1.
Strain | SDF-1 | SDF-2 | % Detergent-resistant spores | % Viable spores |
---|---|---|---|---|
Ax4 | + | + | 99 ± 12 | 89 ± 5 |
stlA null | − | + | 20 ± 7 | 0.5 ± 0.3 |
stlB null | + | + | ND | ND |
gpaA null | − | + | 24 ± 8 | 12 ± 6 |
crlA null | − | + | 30 ± 3 | 11 ± 2 |
acgA null | − | + | 28 ± 5 | 16 ± 4 |
tagB−/K | − | + | 0.11 ± 0.02 | 0.03 ± 0.02 |
Cells from the indicated strains were developed on filters for 24 to 26 h (30 h for the crlA null strain), dissociated in 1 ml starvation buffer, and then spun down. SDF-1 and SDF-2 were purified from the supernatant using cation- and anion-exchange resins, respectively. The amount of each factor was quantified by testing serial dilutions on sporulation of KP cells. Minus indicates less than 10 units per 103 cells; plus indicates at least 103 units of SDF-1 per 103 cells or 104 units of SDF-2 per 103 cells. Detergent-resistant spores were counted after treatment with 0.5% Triton-X 100 and are given as a percent of the initial number of spores. The number of viable spores was determined from the number of plaques on bacterial lawns after 4 to 5 days of incubation of detergent-treated spores. Viable spores are given as a percentage of the initial number of spores Each assay was repeated at least three times.