Department of Life Science, Soochow University, Suzhou, PR China.
Arch Insect Biochem Physiol. 2011 Jun;77(2):72-80. doi: 10.1002/arch.20422. Epub 2011 Mar 23.
For diapause eggs of the silkworm, Bombyx mori, diapause initiation is prevented with hydrochloric acid (HCl) at around 20 h post-oviposition while diapause status is terminated with chilling around 5°C. To investigate whether hydrogen peroxide (H(2)O(2)) and catalase expression are involved in diapause initiation and termination, the concentration of H(2)O(2), relatively higher levels of catalase mRNA and activity of catalase were compared between (1) 20-h-old diapause eggs and the HCl-treated diapause eggs, and (2) 10-day-old diapause eggs and the 5°C-chilled diapause eggs. Compared to diapause eggs, the HCl-treated eggs had significantly higher H(2)O(2) concentrations (up from approximately 1-3 µmol/g fresh mass to 5-8 µmol/g fresh mass), higher relative level of catalase mRNA (up from 0 to 35.2%) and higher catalase activity (up from 2.51 units/mg protein to 4.97 units/mg protein) at 96 h post-treatment. On the other hand, the 5°C chilling resulted in significant increases of H(2)O(2) concentration (up from 0.79 µmol/g fresh mass to 5.57 µmol/g fresh mass), relative level of catalase mRNA (up from 0 to 71.4%) and catalase activity (up from 0.88 units/mg protein to 3.42 units/mg protein) within 120 days. The results obtained in this work suggest that variations of H(2)O(2) and catalase expression in Bombyx eggs are involved in diapause initiation and termination.
对于家蚕的滞育卵，在产卵后约 20 小时用盐酸（HCl）阻止滞育起始，而用 5°C 的冷却来终止滞育状态。为了研究过氧化氢（H₂O₂）和过氧化氢酶表达是否参与滞育的起始和终止，比较了（1）20 小时龄的滞育卵和 HCl 处理的滞育卵之间，以及（2）10 天龄的滞育卵和 5°C 冷却的滞育卵之间的 H₂O₂浓度、过氧化氢酶 mRNA 相对水平和过氧化氢酶活性。与滞育卵相比，HCl 处理的卵具有显著更高的 H₂O₂浓度（从约 1-3 µmol/g 鲜重增加到 5-8 µmol/g 鲜重）、更高的相对过氧化氢酶 mRNA 水平（从 0 增加到 35.2%）和更高的过氧化氢酶活性（从 2.51 单位/mg 蛋白增加到 4.97 单位/mg 蛋白）在处理后 96 小时。另一方面，5°C 的冷却导致 H₂O₂浓度（从 0.79 µmol/g 鲜重增加到 5.57 µmol/g 鲜重）、过氧化氢酶 mRNA 相对水平（从 0 增加到 71.4%）和过氧化氢酶活性（从 0.88 单位/mg 蛋白增加到 3.42 单位/mg 蛋白）显著增加在 120 天内。本工作获得的结果表明，家蚕卵中 H₂O₂和过氧化氢酶表达的变化参与了滞育的起始和终止。
