Fig. 3

LC–MS quantitation of histamine produced by wild type (WT) and mutant L. reuteri strains. Cells were cultured in rich media (MRS) for 24 h, prior to washing and resuspension in buffer (pH 5.0) with l-histidine for 3.5 h. Raw histamine concentrations were normalized to the OD₆₀₀ value in MRS obtained for each sample prior to resuspension. N = 6 biological replicates. Error bars represent ± SEM. One way ANOVA with Dunnett’s multiple comparison test relative to WT. *P < 0.05, ***P < 0.001