Figure 5. Binaphthoquinones generate reactive oxygen species in yeast.

(A) Binaphthoquinones generate ROS in a concentration dependent manner. Yeast wild type strain was treated with DMSO, BiQ7 or BiQ3 at increasing concentrations for 2h and incubated with DHR 123. Experiments were performed three times with similar results. (B). Enhanced generation of ROS in the BiQ hypersensitive mutant coq5Δ in the presence and absence of binaphthoquinone. Yeast wild type and coq5Δ cells were treated with 1 µM BiQ7 or DMSO for 2h and incubated with DHR 123. The experiment was performed three times with similar results. (C) Mitochondrial deficient yeast, rho⁰, are resistant to binapthoquinones. Log-phase cultures of wild-type or rho⁰ yeast at an OD₆₀₀ of 0.1 were treated with DMSO or different concentrations of BiQ7 for 24 (wild type) and 48 (rho⁰) h. Growth curves were performed in triplicate and represent the average of three experiments. P<0.05 for differences between wild-type and rho⁰ yeast at all concentrations of drug.