The oxidative stress response of the filamentous yeast Trichosporon cutaneum R57 to copper, cadmium and chromium exposure

Abstract

Despite the intensive research in the past decade on the microbial bioaccumulation of heavy metals, the significance of redox state for oxidative stress induction is not completely clarified. In the present study, we examined the effect of redox-active (copper and chromium) and redox-inactive (cadmium) metals on the changes in levels of oxidative stress biomarkers and antioxidant enzyme defence in Trichosporon cutaneum R57 cells. This filamentous yeast strain showed significant tolerance and bioaccumulation capability of heavy metals. Our findings indicated that the treatment by both redox-active and redox-inactive heavy metal induced oxidative stress events. Enhanced concentrations of Cu²⁺, Cr⁶⁺ and Cd²⁺ caused acceleration in the production of reactive oxygen species (ROS), increase in the level of oxidatively damaged proteins and accumulation of reserve carbohydrates (glycogen and trehalose). Cell response against heavy metal exposure also includes elevation in the activities of antioxidant enzymes, superoxide dismutase and catalase, which are key enzymes for directly scavenging of ROS. Despite the mentioned changes in the stress biomarkers, T. cutaneum did not show a significant growth diminution. Probably, activated antioxidant defence contributes to the yeast survival under conditions of heavy metal stress.

Keywords:

• filamentous yeast
• oxidative stress
• heavy metals
• antioxidant defence
• biomarkers of oxidative stress

Acknowledgements

The authors gratefully acknowledge support under the Bilateral Scientific Cooperation between the Bulgarian Academy of Sciences and the National Academy of Sciences of Ukraine (period 2013–2015).

Additional information

Funding

This work was supported [grant number BG051PO001-3.3.06-0059], financed by the European Social Fund and Operational Programme Human Resources Development (2007–2013) and co-financed by the Bulgarian Ministry of Education and Science.