关键词: 葱蝇, 滞育, 抗氧化酶, 氧化胁迫, 谷胱甘肽氧化还原循环

Abstract: 【Aim】 In order to investigate the differences of antioxidant system in non-diapause (ND), summer diapause (SD) and winter diapause (WD) pupae of Delia antiqua, the variations of antioxidant enzyme activities and glutathione redox status were determined and compared. 【Methods】 Time-course variations of antioxidant enzyme activities of copper/zinc-SOD (Cu/Zn-SOD), manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR), and contents of reduced glutathione (GSH) and oxidized glutathione (GSSG) and their ratio were measured and compared between different stages of ND, SD and WD pupae of D. antiqua. Canonical discriminate analysis was also conducted to further explore the relationships between the major antioxidant components. 【Results】 The activities of all the five antioxidant enzymes dynamically changed during the whole pupal stage. Compared with ND and SD pupae, WD pupae at the pre-diapause phase had higher Cu/Zn-SOD activities. The mean Cu/Zn-SOD activity in SD or WD pupae at the diapause maintenance phase and post-diapause phase was much lower than that in ND pupae. In the whole pupal stage, ND pupae had higher MnSOD activities than SD and WD pupae, but no difference existed between SD and WD pupae. The average MnSOD activity was distinctly higher than that of Cu/Zn-SOD at the same developmental stage. The CAT activities in SD and WD pupae at the pre-diapause phase were statistically higher than that in ND pupae at the same developmental stage, however, the CAT activities in SD or WD pupae at the diapause maintenance phase and post-diapause phase were significantly lower than those in ND pupae. In either non-diapause or diapause pupae at the same developmental stage, the general GPx activities showed an opposite variation trend with GR activities. Canonical discriminant analysis revealed that antioxidant system in onion fly pupae showed diapause type specificity. 【Conclusion】 Redox status in ND pupae is significantly different from that in SD and WD pupae. Higher antioxidant enzyme activities and lower GSH/GSSG ratio in pupae at the pre-diapause phase and post-diapause phase suggest that the oxidative shift results from a higher respiration rate and development changes.

Key words: Delia antiqua, diapause, antioxidant enzyme, oxidative stress, glutathione redox cycle