Met restriction improves lysosomal function and survival via Hcy reduction. (A) Met levels in E. coli OP50 and HT115 strains. 500 ml of bacterial cells at OD600 0.6 were analyzed for each group. Data are from three independent experiments. (B) Hcy concentrations in WT and cbs-1(yq357) animals grown on E. coli OP50 or HT115. ≥1,000 animals were analyzed for each group. Data (mean ± SEM) are from three independent experiments. (C) Feeding on HT115 E. coli suppresses lysosomal enlargement and shortened body length in cbs-1(yq357) mutants. Left: images of lysosomes (top) co-labeled with NUC-1::mCh and SCAV-3::GFP in the hypodermis of cbs-1(yq357) mutants and DIC images (bottom) of corresponding adults (2 days after L4) grown on E. coli OP50 or HT115. Bars, 5 μm (top left) and 200 μm (bottom left). Middle: quantification of lysosomal sizes (≥20 lysosomes from 3 animals for each genotype). Right: quantification of body length (≥15 animals for each genotype). Data (mean ± SEM) are from three independent experiments. (D) Lifespan of cbs-1(yq357) animals grown on E. coli OP50 and HT115. 100 animals were analyzed for each group. Data (mean ± SEM) are from three independent experiments. (E) Representative images (left) and quantification (right) of NUC-1::mCh-labeled lysosomes in the hypodermis of cbs-1(yq357) single and cbs-1(yq357) sams-1(tm3945) double mutants grown on HT115 E. coli without or with Met and Hcy supplementation. Bars, 5 μm. ≥20 lysosomes from 3 animals were analyzed for each treatment. Data (mean ± SEM) are from three independent experiments. For all quantifications, statistical significance was calculated using the two-sided Student’s t test. **P < 0.01, ***P < 0.001, and ****P < 0.0001. DIC, differential interference contrast.