Oxidative stress response of Saccharomyces cerevisiae exposed to different molecular weight of polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that cause adverse health effects. This study investigated the toxic effect of different molecular weight PAHs on eukaryote model organism (Saccharomyces cerevisiae) exploiting oxidative stress biomarkers as endpoint indicators. Yeast cells were treated with environmentally relevant concentrations of phenanthrene (PHE), fluoranthene (FLA), and benzo[ghi]perylene (BghiP) for 24 h. Benzo[a]pyrene (BaP) was used as a positive control. Subsequently, expression of genes related to oxidative stress responses, cytotoxicity via targeted analysis of antioxidant mutants, generation of reactive oxygen species (ROS), superoxide dismutase (SOD) activity, and glutathione (GSH) content were assessed. The results demonstrated that viability of S. cerevisiae was related to the molecular weight of PAHs. Oxidative stress related genes SOD1 and SOD2 were found to be prominently expressed. According to the redox mechanism of action, BghiP and BaP triggered ROS formation and induced an increasing activity of SOD. Furthermore, PAH exposure significantly affected the glutathione levels. In summary, PAHs clearly caused oxidative stress. Among PAH samples, the more benzene ring contained more toxicity level exerted in yeast cells.