Nojima Yosui
Center for Mathematical Modeling and Data Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
Antioxidants (Basel). 2021 Aug 30;10(9):1385. doi: 10.3390/antiox10091385.
Oxidative stress promotes pupation in some holometabolous insects. The levels of superoxide, a reactive oxygen species (ROS), are increased and superoxide dismutase 1 (BmSod1) and superoxide dismutase 2 (BmSod2) are decreased during metamorphic events in silkworm (). These observations strongly suggest that pupation is initiated by oxidative stress via the down-regulation of BmSod1 and BmSod2. However, the molecular mechanisms underlying ROS production during metamorphic events in silkworm remain unknown. To investigate these molecular mechanisms, the peripheral proteins of BmSod1 and BmSod2 were identified and characterized using dry and wet approaches in this study. Based on the results, silkworm heat shock protein 60 (BmHsp60) was identified as an interacting partner of BmSod2, which belongs to the Fe/MnSOD family. Furthermore, the present study results showed that mRNA expression levels were increased in response to oxidative stress caused by ultraviolet radiation and that BmHsp60 protein levels (but not mRNA levels) were decreased during metamorphic events, which are regulated by the molting hormone 20-hydroxyecdysone. These findings improve our understanding of the mechanisms by which holometabolous insects control ROS during metamorphosis.
氧化应激促进一些全变态昆虫化蛹。在蚕的变态过程中，活性氧超氧化物水平升高，超氧化物歧化酶1（BmSod1）和超氧化物歧化酶2（BmSod2）水平降低。这些观察结果强烈表明，化蛹是由氧化应激通过下调BmSod1和BmSod2引发的。然而，蚕变态过程中活性氧产生的分子机制仍然未知。为了研究这些分子机制，本研究采用干湿法鉴定并表征了BmSod1和BmSod2的外周蛋白。基于这些结果，家蚕热休克蛋白60（BmHsp60）被鉴定为属于Fe/MnSOD家族的BmSod2的相互作用伴侣。此外，本研究结果表明，紫外线辐射引起的氧化应激会使mRNA表达水平升高，并且在由蜕皮激素20-羟基蜕皮酮调节的变态过程中，BmHsp60蛋白水平（而非mRNA水平）会降低。这些发现增进了我们对全变态昆虫在变态过程中控制活性氧机制的理解。
