Fig. 4. Premature aging of wrn-1(RNAi) worms. Wild-type N2 and wrn-1(RNAi) worms at 1 to 7 days of adulthood were photographed on the same day under identical conditions. wrn-1(RNAi) worms were prepared by feeding on E. coli cells producing dsRNA of wrn-1, and growth temperature was shifted from 20°C to 25°C at the L4 stage. (A) Accumulation of lipofuscin autofluorescence. Ten worms of each strain were photographed every day, and one worm with an averaged intensity of autofluorescence is shown. (B) C. elegans heads were photographed with a Nomarski optics microscope. Photographs of heads were given a score of 1-5, with 1 representing a youthful appearance and 2-5 denoting increasing orders of overall deterioration in the tissue. (C) Scatter diagram of the values assigned to tissue deterioration in the head. Each dot corresponds to a single animal. Scale bars: A, 500 µm; B, 50 µm.