Umwelt- und analytische Toxikologie

Effect of -Induced Oxidative Stress on Sclerotial Differentiation and Asa-GSH Cycle of Penicillium thomii Q1 Strain

Abstract

Wenjing Zhao and Jianrong Han

Penicillium thomii Q1 strain was able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. The aim of this work was to determine the effects of H2O2-induced oxidative stress on the sclerotial differentiation and ascorbate-glutathione (AsA-GSH) cycle of Q1 strain. Results showed that the oxidative stress induced by H2O2 was clearly dependent on the H2O2 concentrations in media. The higher the concentration of H2O2 was, the higher the sclerotial biomass and carotenoids content in sclerotia (Rbiomass=0.972, Rcontent=0.941) (P<0.05). H2O2- induced oxidative stress favored the sclerotial differentiation. Results indicated that H2O2-induced oxidative stress can improve the contents of reduced form of ascorbate (ASC) and dehydroascorbate (DHA) and the ratio of ASC/DHA in sclerotia of Penicillium thomii Q1 strain (RASC=0.727, RDHA=0.640, RASC/DHA=0.929). The contents of DHA and ASC were increased by 1.9-fold and 2.4-fold with respect to control. At the same oxidative stress condition, DHA content was higher than ASC content. Oxidative stress may increase the contents of reduced glutathione (GSH) and oxidized glutathione (GSSG) in sclerotia of Penicillium thomii Q1 strain (RGSH=0.888, RGSSG=0.997). The value of the ratio of GSH/GSSG had a negative correlation with the oxidative stress (R=-0.933). At the same oxidative stress condition, GSH content was higher than GSSG content. The values of Ascorbate peroxidase (APX) and Glutathione reductase (GR) activities had negative correlation with the oxidative stress (R APX=-0.555) (RGR=-0.420). The values of Monodehydroascorbate reductase (MDHAR) and Dehydroascorbate reductase (DHAR) activities had positive correlation with the oxidative stress (RMDHAR=0.448) (R DHAR=0.603).