Regulation of the antioxidant system in cells of the fission yeast Schizosaccharomyces pombe after combined treatment with patulin and citrinin

• Combined treatment with 250 μM PAT and 250 μM CTN for 1 h induced elevated levels of peroxides in Schizosaccharomyces pombe cells.
• The PAT + CTN-induced changes in the levels of intracellular ROS were similar to those caused by CTN treatment alone.
• PAT + CTN co-treatment altered the pattern of antioxidant enzyme activities as compared with the treatment of individual toxins.

The effects of combined treatment with patulin (PAT) and citrinin (CTN) on Schizosaccharomyces pombe cells were investigated in acute toxicity tests. In comparison with the controls the exposure of fission yeast cells (107 cells ml−1) to PAT + CTN (250 μM each) for 1 h at a survival rate of 66.6% significantly elevated the concentration of total reactive oxygen species (ROS) via increased levels of peroxides without affecting the concentrations of superoxides or the hydroxyl radical. This treatment induced a 3.08-fold increase in the specific concentration of glutathione and elevated specific activities of catalase and glutathione S-transferase, while at the same time the activity of glutathione reductase decreased. The pattern of the ROS was the same as that induced by CTN (Máté et al., 2014), while the presence of PAT in the PAT + CTN combination treatment modified the activities of the antioxidant system (Papp et al., 2012) in comparison with the individual PAT or CTN treatment, suggesting toxin-specific regulation of glutathione and the enzymes of the antioxidant system and the possibility that the transcription factor (pap1 and atf1) -regulated processes might be influenced directly by ROS.