Table 1.

Presence of SDF-1 and SDF-2 in wild-type and mutant fruiting bodies^a

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

^aCells 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.