Fig. 1
L. plantarum evolution in mice leads to higher adaptation to the host intestinal environment. A Schematic representation of the LpNIZO2877experimental evolution (EE) protocols in the mouse diet (Diet setup) and mouse intestine (Host setup). The ancestral strain was inoculated in the mouse laboratory diet and in the mouse intestine by intragastric gavage. Five and two replicates of EE were performed for the Diet and the Host setup, respectively. An evolved bacterial subpopulation was plated out on MRS agar plates for colony counting at different time points throughout the EE in both setups. The EE in the Diet setup was conducted up to 20 transfers (i.e., ~20 days, corresponding to approximately 400 Lp generations). In the mouse intestine, Lp EE was carried out from generation 0 (F0) to 4 (F4) of mice (i.e., 10 months after the mono-association, ~300 days, corresponding to ~286 Lp generations) for one replicate and for one generation (F0) (3 months after the mono-association) for the second replicate. Four female mice were housed in a single cage. One male and two female mice were housed in a separate single cage. BLpNIZO2877 growth trend monitored over the course of the EE in both experimental setups (Host and Diet). C Final absorbance values (OD = 600) reached by the Lp strains under standard growth conditions (MRS broth) and in MRS broth added to with 0.3% bile acids (BA). S indicates smooth colonies, while R indicates rough colonies. Each dot represents the mean of at least three experimental replicates per condition, with bars indicating the respective SD (standard deviation). For both experimental conditions (MRS broth and MRS broth + 0.3% BA), asterisks indicate significance between the final absorbance values of each strain against those of the LpNIZO2877ancestor (unpaired t test; *p ≤ 0.05, **p < 0.01, and ***p < 0.001). D Quantitative PCR analysis of LpNIZO2877 ancestral strain (Anc) and LpNIZO2877-derived population (Evo) evolved in the mouse intestine. Each bar represents the standard error of the mean (SEM) of normalized ∆CT ratios (1/∆CT) of 3–4 mice/group. Statistical significance of the results is included (unpaired t test, **p≤0.01)