Hormonal control of pupal commitment and programmed cell death

本研究结果表明：(1)激素滴度：JH在第三龄至化蛹期间每隔12h测定一次血淋巴保幼激素和蜕皮激素滴度，从第四龄至化蛹期间每隔2 h测定一次蜕皮激素滴度。(2)翅盘的化蛹：在末次幼虫蜕皮后16h，翅盘中的承诺变化完成。20-羟基蜕皮激素不能加快这种变化的速度，JH在生理剂量下也不能抑制这种变化。JH也不影响承诺的变化。20E。承诺的改变可能在头囊滑脱(HCS)时开始。在HCS后，这些磁盘对20E有显著的响应，而对JH失去了响应。第四体育场早期的盘片，在体外20E前还没有被瞳孔诱导，可以通过两步孵育，首先不加激素，然后20E激发。在此条件下，视盘呈瞳孔定位，低于生理浓度的JH对其定位有较强的抑制作用。(3)前丝腺程序性细胞死亡：体外20E可诱导前丝腺细胞凋亡。20E攻击后，死亡所需的基因表达和蛋白质合成分别在8h和18h内完成。然而，20E必须存在42小时才能完成死亡。与其他证据一起，20E被认为在18h后通过一个膜结合的受体起作用，第二个信使是环磷酸腺苷。已经克隆了7个早期基因，其中5个与其他动物的已知基因同源，但2个没有开放阅读框。对它们的功能的分析正在进行中。

Present research determined and showed the followings during the propqsed period.(1) Hormone titer : Hemolymph juvenile hormone and ecdysteroid titers were determined every 12 h for JH during a period from third stadium to pupation and every 2 h for ecdysteroids from 4th stadium through pupation.(2) Pupal commitment of for wing discs : The change in commitment in wing discs was found to be finished for 16 h after last larval ecdysis. 20-Hydroxyecdyosne did not accelerate the rate of the change and JH failed to suppress the change at a physiological dose. JH also did not affect the change in commitment by. 20E. The change in commitment may be initiated at the time of head capsule slippage (HCS). After HCS, the discs became responsive dramatically to 20E while lost their responsiveness to JH. The discs of early 4th stadium, that were not pupally committed by 20E in vitro, were able to be pupally committed by two step incubation, first with no hormone followed by 20E challenge. In such conditions, the discs were pupally committed and the commitment was strongly suppressed by JH at a concentration lower than physiological one.(3) Programmed cell death of anterior silk gland : Apoptosis of anterior silk gland is induced by 20E in vitro. After 20E challenge, gene expression and protein synthesis necessary for the death were completed within 8 and 18 h, respectively. Nevertheless, 20E must be present for 42 h for completion of the death. Along with other evidence, 20E was suggested to act after 18 h through a membrane-bound receptor and the second messenger is cyclic AMP. Seven early genes have been cloned and five of them exhibited homology of known genes in other animals but two did not possess open reading frame. Analysis of their function is under progress.