FIG. 5.
Effect of mutation V335A on the glucose-mediated spore germination response. Spores of strain GC-L5V335A (⧫) display an extended lag phase and slower loss of A600 when incubated in 10 mM glucose (A) than the parental strain GC-GerU* (⋄). The mutant spores also require an increased glucose concentration to stimulate a significant degree of spore germination (50% germination at approximately 3.7 mM) (B). Spores were germinated in 96-well plates in a total volume of 300 μl of 5 mM Tris-HCl, pH 7.8, at 30°C with variable glucose concentrations. Under these experimental conditions, a 60% loss in A600 correlates with 100% spore germination, as determined by loss of heat resistance of strain GC-GerU* after a 60-min incubation in 10 mM glucose. This value was used subsequently to estimate the proportion of germinated spores after incubation for 60 min under the range of glucose concentrations tested. Experiments were conducted in triplicate. In panel B, error bars represent standard deviations from the mean.