Functions of antioxidant enzyme activities on the membrane bound total sialic acid and lipid peroxidation level in F. equiseti and F. acuminatum

The variations of membrane bound total sialic acid (TSA) and lipid peroxidation level dependent on the antioxidant enzyme activities such as Superoxide Dismutase (SOD), Catalase (CAT), Glutathione peroxidase (GSH-Px) have been studied in yeast extract supplemented medium. The maximum SOD and CAT activities of F. equiseti tended to increase with raises of yeast extract concentration up to 25 g/L where they were determined to be 78.6 +/- 0.96 and 312.7 +/- 5.6 IU/mg. On the other hand, SOD and CAT activities in F. acuminatum significantly increased with the rise of yeast extract concentration up to 10 g/L (p < 0.01) and maximum activities were observed at this concentration as 36.3 +/- 0.54 and 115.3 +/- 2.19 IU/mg on the 12th day incubation. Other H2O2 scavenger enzyme, GSH-Px activities of F. equiseti and F. acuminatum were reached the maximum at 5 and 25g/L yeast extract and determined as 5.06 +/- 0.04 and 4.74 +/- 0.09 IU/mg, respectively. TSA level showed positive correlation with SOD and CAT activities while LPO levels variations negatively correlated. The results may indicate that these antioxidant enzymes also appeared to be involved in protecting membrane bound sialic acids as well as membrane lipid of the fungus from exogenous reactive oxygen species.