Figure 3.

Metformin Effects on C. elegans Lifespan Correlate with Effects of Metformin on Bacterial Growth

(A) Metformin extends lifespan in the presence of respiratory-deficient E. coli strain GD1.

(B) Growth in the presence of metformin does not impair respiration in E. coli OP50.

(C–E) Effects on lifespan are independent of bacterial subgroup (B or K-12) and lipopolysaccharide (LPS) structure. K-12 strains possess longer LPS structures than B strains and CS2429. CS2429 is an LPS truncated mutant derived from isogenic parent strain CS180. HB101 is a B/K-12 hybrid.

(F) Relationship between bacterial growth inhibition by metformin (50 mM) and effects on lifespan among different E. coli strains.

(G) OP50-MR E. coli is resistant to growth inhibition by metformin. This strain also shows cross-resistance to phenformin (Figures S3C–S3E).

(H) Metformin shortens lifespan in the presence of OP50-MR.

Error bars represent SEM. ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001. See also Figure S3. For statistics, see Table S3.