Fig. 1.

Young individuals demonstrate a stronger ability to generate ROS. (A) Relative ROS levels were measured using the DCFH-DA fluorescent probe in young and old worms cultured on NGM plates in the presence or absence of PQ (0.1 mM) for 1 day. (B) Relative O₂⁻ levels were measured using the MitoSox fluorescent probe in young and old worms in the presence or absence of PQ (0.1 mM) for 1 day. (C) The 488/405 fluorescent ratio in young and old Pmyo3-HyPer transgenic worms after PQ treatment was measured to assay changes in H₂O₂ levels. (D) At each passage after p30, human fibroblasts were counted, and the doubling time was calculated. p42 cells exhibited a greatly increased doubling time as cells entered senescence. (E) Relative average telomere lengths indicated by the T/S ratio were measured by performing qPCR. (F) At some passages, cells were analyzed for β-gal staining. At passages 41and 42, the majority of the cells were blue, indicating senescence was activated. (G) Relative ROS levels were measured using the DCFH-DA fluorescent probe in young and old cells that were treated with PQ (100 μM) for 12 h, 24 h or 48 h. PBS treatment was used as a control. (H) Relative O₂⁻ levels were measured using the MitoSox fluorescent probe in young and old cells treated with PQ for 12 h or 24 h. The error bars show the SEM (n=3).