Cyanide-resistant alternative respiration is strictly correlated to intracellular peroxide levels in Acremonium chrysogenum

A strict correlation between the intensity of the cyanide-resistant alterna tive respiratory pathway and the intracellular peroxide levels in the cepha losporin C producer filamentous fungus Acremonium chrysogenum was demonstra ted. Intracellular peroxide levels increased in a dose-dependent manner aft er addition of H2O2 to the culture media. A similar phenomenon was observed due to the specific inhibition of catalase by salicylic acid. In both case s, cyanide-resistant respiration was markedly stimulated. On the other hand , both cyanide-resistant respiration and intracellular peroxide levels were effectively suppressed by the lipid peroxyl radical scavenger DL-alpha -to copherol, which breaks lipid peroxidation chains effectively. Our findings firmly supported the assumption that there is a connection between the intr acellular peroxide levels and the intensity of the alternative respiratory pathway in fungi.