Figure 3.

Mutation of SlpB drastically affects stress tolerance in P. freudenreichii CIRM-BIA 129. (A) The growth curve of Wild-type (WT) and mutant CB129ΔslpB strains was determined at 30°C in YEL broth until stationary phase (72 h). Growth was monitored by OD_{650 nm} as a function of time. No statistically significant difference was found in growth curve between strains. (B) Wild-type (WT) and mutant 129ΔslpB strains were subjected to acid, bile salts and thermal challenges. Viable propionibacteria were enumerated by plate counting before and after each challenge. Asterix represent statistically significant differences between strains and were indicated as follows: **p < 0.01.