Skip to main content
. 2014 Oct;196(19):3399–3409. doi: 10.1128/JB.01899-14

FIG 1.

FIG 1

Effects of a variety of ypeB mutations on the germination and outgrowth of decoated B. anthracis spores. Decoated spores were heat activated and were germinated in BHI medium at 37°C. The data shown are averages of results from three independent spore preparations; error bars are omitted for clarity. (A) Germination and outgrowth are blocked in decoated ΔypeB spores. Wild-type (●), ΔsleB (□), ΔypeB (▲), and ypeB complementation (ypeB+) (⬥) strains were analyzed. The germination rates of ΔsleB and ΔypeB spores were statistically indistinguishable (P > 0.23), as were the germination rates of wild-type and ypeB+ spores (P > 0.08). Both ΔsleB and ΔypeB spores were significantly different (P < 0.04) from wild-type and ypeB+ spores during stage II of germination, from 45 to 95 min. (B) Truncations removing YpeB PepSY domains block decoated-spore germination. ΔypeB (▲), YpeB1–208-His6 (△), YpeB1–283-His6 (+), YpeB1–368-His6 (□), YpeB1–446-His6 (—), and ypeB+ (⧫) strains were analyzed. The germination rates of ypeB+ and YpeB1–446-His6 spores were not statistically different (P > 0.08); likewise, the germination rates of ΔypeB and YpeB1–283-His6 spores were statistically indistinguishable (P > 0.49). YpeB1–208-His6 and YpeB1–368-His6 spores did not differ (P > 0.05) from ΔypeB spores during germination, except at 55 min and from 45 to 55 min, respectively (P < 0.05). The germination rates of YpeB1–208-His6, YpeB1–283-His6, and YpeB1–368-His6 spores were not statistically different (P > 0.11) from 4 min onward. (C) Point mutations in YpeB PepSY domain conserved residues slow decoated-spore germination. ΔypeB (▲), YpeBY254A (■), YpeBY329A (×), YpeBT377A (○), YpeBY410A (●), YpeBG430A (◇), and ypeB+ (⬥) strains were analyzed. Statistical analysis of ypeB point mutants is complex due to the greater variability of germination rates of decoated-spore preparations, as well as the fact that spores of some strains are initiating outgrowth while others are still germinating. During stage II of germination, between 45 and 95 min, YpeBY329A and YpeBT377A spores were not significantly different from ypeB+ spores (P > 0.38). The germination rates of YpeBY254A spores from 80 to 90 min, YpeBY410A spores from 45 to 55 min and 70 to 95 min, and YpeBG430A spores at 50 min and from 75 to 95 min were significantly different from that of ypeB+ spores (P < 0.05).