Fig. 6

B. longum strains with specific genotypes can significantly reverse behavioral changes in aging mice. A Ability of B. longum strains with different SNP statuses [five positive strains (with AGT allele at genomic loci 891,726, 891,804, and 891,054): 278(O1), RG4-1 (O2), FJSWXJ10M2 (O3), ZCC2 (O4), and ZCC5 (O5); and five negative strains (with GTC allele): FGSZY16M3 (Y1), FHaNCM25GMM1 (Y2), FSDLZ59M1 (Y3), ZCC12 (Y4), and CCFM752 (Y5)] in arginine biosynthesis pathway genes to increase arginine levels in culture supernatants. B Locations of six selected phylogenetically distant strains [three positive strains with higher ability to increase arginine level in vitro: O1, O2, and O3; and three negative strains with lower ability to increase arginine level: Y1, Y2, and Y3] used in the mice in a neighbor-joining tree. C Diagram of the experimental design. Please see the “Methods” section for additional details. Behavioral parameters. Open-field test (D and E), step-through test (F), Y-maze (G), and Morris water maze (H and I). The normal distribution of all data was confirmed using the Kolmogorov–Smirnov (KS) normality test. All data were analyzed using one-way ANOVA and are presented as the means ± standard errors of the means; n ≥ 3 for each group. Arg, Arginine group. Statistical significance was calculated for the comparisons between the aging group and the control group (*s in green color), and for the comparisons between the aging group and each of strain treatment groups (*s in the other colors). *P < 0.05, **P < 0.01, ***P < 0.001