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作者Gu, S.H.;Tsai, W.H.
出版日期2012
著作名稱Decreased JH biosynthesis is related to precocious metamorphosis in recessive trimolter (rt) mutants of the silkworm, Bombyx mori
刊名Archives of Insect Biochemistry and Physiology
79
4-5
頁數235-246
被收錄索引SCI
關鍵字Bombyx mori; juvenile hormone; metamorphosis
摘要In recessive trimolter (rt) mutants of the silkworm, Bombyx mori, that have four larval instars rather than the five larval instars of normal B. mori, a decrease after a small increase in the hemolymph ecdysteroid titer during the early stages of the last (fourth) larval instar appeared to be a prerequisite for larvae to undergo precocious metamorphosis. The present study was carried out to investigate the possible mechanism underlying this decrease in the ecdysteroid titer. It was found that juvenile hormone (JH) biosynthetic activity of the corpora allata (CA) increased during the first day of the last larval instar, but its absolute JH biosynthesis activity was relatively lower compared to that of normal fourth instar larvae in tetramolters. This lowered JH biosynthetic activity appeared to be related to a decrease in prothoracic gland ecdysteroidogenesis during the second day of the last instar, because hydroprene application prevented this decrease in prothoracic gland ecdysteroidogenesis, leading to the induction of a supernumerary larval molt. The in vitro incubation of prothoracic glands with hydroprene showed that hydroprene did not directly exert its action on PTTH release. Further study showed that the application of hydroprene enhanced the competency of the glands to respond to PTTH. From these results, it was supposed that the lowered JH biosynthesis of the CA during the first day of last instar in rt mutants was related to decreased ecdysteroidogenesis in the prothoracic glands during the second day, thus playing a role in leading to precocious metamorphosis.
DOI10.1002/arch.21010
系統號NO000003757

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