Fig. 6

Membrane potential measurements for WT and mutant L. reuteri strains under neutral conditions. 24-hour MRS cultures were washed and loaded with DiOC₂ [3], and resuspended in PBS alone (b), +CCCP (a), +15 mM d-histidine (c), or +15 mM l-histidine (d). Signal was recorded in red and green channels in a plate fluorescence reader. N = 4 biological replicates per group. Two-way ANOVA with Tukey’s multiple comparison test. Error bars represent ± SEM. Under neutral conditions, there were no significant differences (n.s.) in membrane potential among treatments or across strains. n.s. not significant