Research Paper Volume 12, Issue 3 pp 2680—2697

Methionine increases yolk production to offset the negative effect of caloric restriction on reproduction without affecting longevity in C. elegans

Figure 1. Methionine supplementation prevents calorie restriction (CR) to reduce egg production and survival. (A) Egg production was reduced by CR and rescued by methionine. Ad libido (AL) and CR conditions were achieved by plating 1X1011/mL and 1X108/mL OP-50 bacteria, respectively, on solid nematode growth (NG) medium containing carbenicillin and kanamycin. Worms were raised on NG medium supplemented with indicated concentrations of methionine (Met) from hatching to day-1 adulthood. Worms (n>25) were allowed to lay eggs for 3 hours and egg production were evaluated in per worm per hour (egg/worm/h). Data were collected from 3 independent experiments. P values were obtained by t-test: ns, not significant; **, P<0.001. (B) Embryos survival rate was reduced b CR and rescued by methionine. Worms were raised on AL and CR conditions to day-1 adulthood and eggs were collected within 3 hours to obtained synchronized embryos. Hatching rate was determined by examining the number of dead eggs and larvae at L2/L3 stage. Data were collected from 3 independent experiments with each experiment examining n>100 animals. P values were obtained by t-test: **, P<0.001. (C) Egg production was reduced in CR model (eat-2 mutant) and rescued by methionine. N2 wild-type and eat-2(ad1116) worms were raised on NG medium supplemented with and without 5mM methionine (Met) today-1 adulthood. Egg production was evaluated as in A. Data were collected from 3 independent experiments. P values were obtained by t-test: **, P<0.001. (D) Embryos survival rate was reduced in CR model (eat-2 mutant) and rescued by methionine. N2 wild-type and eat-2(ad1116) worms were raised on NG medium supplemented with and without 5mM methionine (Met) today-1 adulthood. Embryo survival rate was determined as in C. Data were collected from 3 independent experiments. P values were obtained by t-test: ns, not significant; **, P<0.001.