Influence of the oxidative stress induced by the organophosphate pesticide bromopropylate on the mitochondrial respiratory chain in Trichoderma harzianum

• The effect of bromopropylate of Trichoderma harzianum on respiratory chain discussed.
• The variations of ETC enzymes were determined with respect to bromopropylate.
• Higher bromopropylate concentrations lead to cellular anoxic conditions instead of glycolysis.
• TCA cycle metabolites variations of T. harzianum affected by bromopropylate.
• The imbalance in the respiratory chain of T. harzianum caused membrane damage.

The present study was designed to investigate the effect of bromopropylate on its own transport rate, glycolysis and tricarboxylic acid cycle metabolite levels, adenine nucleotides, and membrane lipid peroxidation (LPO) as well as the activities of mitochondrial electron transport chain (ETC) enzymes in eukaryotic Trichoderma harzianum. The transport rate of bromopropylate reached a maximum level within the first 24 h of incubation for all studied concentrations. The succinate dehydrogenase (SDH) and cytochrome c oxidase (CCO) activities reached their maxima at 72 h for 2.5 and 10 mg/L of bromopropylate, respectively. In addition, the intracellular pyruvate levels increased for bromopropylate concentrations up to 2.5 mg/L. The maximum intracellular α-ketoglutarate level was determined at 5 mg/L, while the intracellular fumarate and citrate levels reached their maximums at 7.5 mg/L of bromopropylate. The variations in the adenine nucleotide levels showed a positive correlation with both α-ketoglutarate and fumarate levels. Nevertheless, the LPO levels increased with increasing bromopropylate concentrations. These results may indicate that the membrane becomes more damaged from an impaired respiratory chain, which may then cause an increase in electron leakage.