Stage-specific regulation of juvenile hormone biosynthesis by ecdysteroid in Bombyx mori
Stage-specific regulation of juvenile hormone biosynthesis by ecdysteroid in Bombyx mori
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家蚕蜕皮激素对保幼激素生物合成的阶段特异性调节
DOI：
10.1016/j.mce.2011.01.012
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
K
中科院分区：
文献类型：
--
作者：
Kaneko;Y.;Kinjoh;T.;Kiuchi;M.;and Hiruma;K
在家蚕倒数第二（4）龄幼虫中，咽侧体（CA）合成保幼激素（JH）是波动的。当饲喂含20-羟基蜕皮激素（20 E）的饲料时，随着蜕皮激素滴度的增加，CA的JH合成活性首先受到刺激，然后被较高蜕皮激素浓度（> 250 ng/ml）轻微抑制。JH生物合成酶在CA中的表达调节JH生物合成活性的整体：主要是JH酸O-甲基转移酶（JHAMT），异戊烯基二磷酸异构酶，和法呢基二磷酸合成酶1。在最后一次（第5次）幼虫蜕皮后，由于20 E饮食而人为增加的高蜕皮激素水平激活了CA的JH合成，这需要与大脑的完整神经连接。来自20 E激活的脑的因子主要控制JHAMT和HMG Co-A还原酶表达以刺激JH合成。在正常的末龄幼虫，蜕皮类固醇滴度下降，使这些激活机制是不存在的，因此，蜕皮类固醇滴度下降后，最后的幼虫蜕皮是一个因素，诱导停止JH合成CA。
In the penultimate (4th) instar larvae of Bombyx mori, juvenile hormone (JH) synthesis by corpora allata (CA) fluctuates. When diet containing 20-hydroxyecdysone (20E) was fed, JH synthetic activity of the CA was first stimulated as the ecdysteroid titer increased, then suppressed slightly by the higher molting concentration of ecdysteroids (>250ng/ml). The overall JH biosynthetic activity was modulated by the expression of JH biosynthetic enzymes in the CA: primarily JH acid O-methyltransferase (JHAMT), isopentenyl diphosphate isomerase, and farnesyl diphosphate synthase 1. After the last (5th) larval ecdysis, the artificially increased high ecdysteroid level due to the 20E diet activated JH synthesis by the CA, which required intact nervous connections with the brain. A factor(s) from the 20E-activated brain controls mainly JHAMT and HMG Co-A reductase expression to stimulate the JH synthesis. In the normal last instar larvae, the ecdysteroid titer declines so that these activation mechanisms are absent; therefore the decline of the ecdysteroid titer after the final larval ecdysis is one of the factors which induces the cessation of the JH synthesis by CA.