Figure 6

Involvement of CtsR and HrcA in hydrogen peroxide resistance. A) Colony forming units of L. plantarum WCFS1 (wt, squares), NZ3410 (ΔctsR, diamonds), NZ3425^CM (ΔhrcA, circles), and NZ3423^CM (ΔctsR ΔhrcA, triangles) cultures when subjected to 40 mM H₂O₂ exposure. As a control, the ΔctsR ΔhrcA strain was taken for incubation in PBS without H₂O₂ (dashes). Lines indicate the fitted reparameterized Weibull model data. Data shown are representative for 3 independent experiments. B) Time to the first 4 log₁₀ reductions (t _4D ) for the same strains as in panel A. The t _4D -value is the parameter estimate obtained by fitting a reparameterized Weibull model through the data and average for the 4 experiments. Error bars represent the 95% confidence interval of the parameter estimate. Significant difference from the wt (p < 0.05) is indicated by *.