Cyanide-insensitive respiration in Schizophyllum commune

Area of Science:

• Mycology
• Biochemistry
• Genetics

Background:

• Schizophyllum commune is a model hymenomycete fungus.
• Fungal respiration typically involves a cyanide-sensitive cytochrome pathway.
• An alternative respiratory pathway, cyanide-insensitive, is known in some fungi but not yet characterized in hymenomycetes.

Purpose of the Study:

• To investigate respiratory pathways in Schizophyllum commune mutants.
• To identify genetic basis for altered respiratory function.
• To explore the presence of alternative respiratory pathways in hymenomycetes.

Main Methods:

• Isolation and characterization of two Schizophyllum commune mutants deficient in acetate utilization.
• Growth analysis on glucose minimal medium with sodium azide.
• Genetic analysis to map mutations.
• Measurement of endogenous respiration and its inhibition by cyanide and 8-hydroxyquinoline.

Main Results:

• Mutants showed limited growth inhibition by sodium azide.
• Both mutants displayed high cyanide-insensitive endogenous respiration.
• 8-hydroxyquinoline partially inhibited respiration, indicating a dominant alternative pathway.
• Wild-type strains exhibited enhanced cyanide-insensitive respiration when grown with sodium azide.

Conclusions:

• Schizophyllum commune possesses a cyanide-insensitive alternative respiratory pathway.
• This pathway can be induced by environmental stress (sodium azide).
• The study provides the first evidence of this alternative pathway in hymenomycetes.