Temperature Pre-Treatment Modulates Oxidative Protection of Aspergillus Niger Cells Stressed by Paraquat and Hydrogen Peroxide

The protective effect of pretreatment with low oxidative stress factors is little known in relation to the growth and development of filamentous fungi. The acquisition of new knowledge can be particularly useful for industrially important fungal strains. In the present study, the adaptive response of the filamentous fungus Aspergillus niger 26 to oxidative stress has been examined. The findings indicate that pretreatment with a sub-lethal temperature leads to the development of resistance to lethal concentrations of paraquat (PQ), H2O2 and extremely high temperatures. Fungal cultures subjected to 35°C followed by exposure to high doses of stress agents showed a higher amount of biomass accumulation compared to the single treated cells. The pre-exposure strategy exerted a protective effect with respect to the amount of oxidatively damaged proteins in A. niger cells, which was accompanied by a corresponding increase in the intracellular protein content and induction of antioxidant enzymes compared to the non-adapted cultures. At the same time, the results demonstrated different responses in the temperature-adapted cells. Pretreatment makes cells more resistant to both PQ and temperature than to H2O2.