Reduced triosephosphate isomerase (TPI) activity increases oxidant resistance of S. cerevisiae and C. elegans. (a) The left panel shows a Western blot analysis of yeast cells expressing wild-type human TPI under the control of promoters of different strengths: GPD1 (GPD
), TEF1 (TEF
), and CYC1 (CYC
). Yeast cells expressing human TPIIle170Val or yeast TPI under the control of the strong GPD1 promoter were used as controls. Equal loading of the lysates was controlled by visualizing G6PDH. The right panel shows yeast cells expressing yeast TPI and human TPIIle170Val controlled by the GPD1 promoter or yeast expressing wild-type human TPI controlled by the GPD1, TEF1 or CYC1 promoters, respectively. Yeast were spotted as fivefold serial dilutions on SC medium supplemented with different concentrations of diamide. Plates were incubated at 30°C for 3 days. (b) The left panel shows western blot analysis of cell extracts prepared from adult C. elegans that were fed with E. coli producing double-stranded RNA of the C. elegans tpi-1 gene (Y17G7B.7) (tpi-1 RNAi) or harboring the empty plasmid L4440 (control). The right panel shows the effects of the oxidants juglone and diamide on these worms. After feeding with E. coli as described above, worms were placed on agar plates supplemented with juglone or diamide. Multi-resistant daf-2 (e1370) mutant worms were included in every experiment as controls.