FIG 6.

Sporulation efficiency of lcp variants. Bacilli from overnight cultures of B. anthracis Sterne (WT) and isogenic variants carrying a single lcp gene were washed, suspended in modG sporulation medium at an A₆₀₀ of 1, and incubated at 30°C with shaking. (A) Culture aliquots were taken immediately following inoculation into modG medium, serially diluted, and plated to enumerate viable bacteria at time 0 (CFU). (B) Culture aliquots were collected at 24, 48, and 96 h following inoculation into modG medium, heat treated at 68°C for 30 min to kill vegetative bacilli, serially diluted, and plated to enumerate spores. (C) Culture aliquots from the 48-h time point were also fixed and visualized by phase-contrast microscopy. Representative images are shown. The scale bar represents 10 μm.