Figure 1. Uric acid extends the life span of C. elegans. (A) Chemical structure of uric acid. (B) Survival of animals treated with 2 mM uric acid on paraquat and the untreated controls. (C) Quantitation of intracellular levels of ROS in animals treated with 2 mM uric acid and those in untreated controls at day 1 adulthood. PQ is the abbreviation for paraquat, and NAC represents N-acetyl-cysteine. Data are the means ± SD, n ≥ 30, * P < 0.05, *** P < 0.001 (Student’s t test). (D) Survival analysis of wild-type N2 animals raised at increasing concentrations (0.02-100 mM). (E) Dose-response analysis of uric acid. The average life span changes from at least three independent experiments. (F) Survival curves of animals treated with 2 mM uric acid at 20 °C and those of untreated controls. Uric acid exposure was administered beginning on day 1 of adulthood. Life span was analyzed using the Kaplan-Meier test, and P values were calculated using the log-rank test. Data are representative of at least three independent experiments, and details on the life span values are summarized in Supplementary Table 1 in the Supporting Information.