engleski

Response of Chlorella kessleri cells to oxidative stress induced by herbicides

Two herbicides, chloroacetanilide S-metolachlor and triazine terbuthylazine, as well as hydrogen peroxide were applied in order to study the response to oxidative stress of Chlorella kessleri Fott et Nováková culture. Exposure of algal cells to toxicants increased the reactive oxygen species production leading to the decrease in the growth rate of the culture and photosynthetic pigment concentration, changes in cell ultrastructure, antioxidative response and the formation of lipid peroxidation end-product 4-hydroxy-2-nonenal (HNE). Lipid peroxidation indicates the limited effectiveness of measured enzymatic (catalase, ascorbate peroxidase and glutathione reductase) as well as non-enzymatic antioxidants (phenolics, ascorbic acid and carotenoids). Beside the toxic effects, low HNE concentrations found in untreated, control cells emphasise its physiological role in algae. Presence and accumulation of HNE-protein adducts detected in the cells of green unicellular algae could help indicate environmental pollution with herbicides as well as with other oxidative stress-inducing compounds. Though many deleterious effects have been attributed HNE, its role in signaling and adaptation to stress in plants and algae, remains to be fully characterized. As animal cells are incapable to adequately metabolize high concentrations of HNE one could assume that algae intoxicated in this manner, in combination with HNE, could also serve as a potential biohazard in aquatic food webs.

S-metolachlor; terbuthylazine; reactive oxygen species; 4-hydroxy-2-nonenal; antioxidants

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