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Control of Metamorphosis by PTTH and bombyxin in the silkworm Bombyx mori.

PTTH 和家蚕素对家蚕变态的控制。

基本信息

批准号：
07640882
负责人：
MIZOGUCHI Akira
金额：
$ 0.64万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

We have developed a time-resolved fluoroimmunoassay for Bombyx prothoracicotropic hormone (PTTH) and determined the PTTH titers in the Bombyx hemolymph throughout development from the third larval ecdysis to the adult emergence. PTTH peaks were observed at specific stages in the molting cycles. During the early adult-development, a daily rhythm of the PTTH titer fluctuation was noticed. A small amount of PTTH was also present in the hemolymph over the first half of the fifth instar. We next measured the ecdysteroid titer in the same hemolymph samples as used for PTTH titer determination, to correlate the titer change patterns for PTTH and ecdysteroids. The release of ecdysteroids was closely related to that of PTTH both in timing and in amount, strongly suggesting a crucial role of PTTH in the control of the prothoracic gland activity. From the dynamics of both hormones, dual actions of PTTH on the prothoracic glands, acute and delayd, were suggested. The effects of PTTH antibody injection as assessed by the delay of wandering suggested that PTTH present at low titers in the hemolymph of the early fifth instar larvae also acts somehow on the prothoracic glands.The control mechanisms of PTTH secretion were also investigated. The phase-shift of the light-dark cycles resulted in the shift of the PTTH peaks in timing, suggesting that the PTTH release is regulated to occur at a specific phase in the light-dark cycles. When day-2 fifth instar larvae were starved, the hemolymph PTTH titer was decreased and, on refeeding, increased rapidly, suggesting that the PTTH release in the early fifth instar is affected by the nutritional conditions.

我们已经开发了一种时间分辨荧光免疫分析法测定促前胸腺激素（PTTH），并确定了PTTH滴度在整个发展过程中，从第三幼虫蜕皮到成人出现的血淋巴。在蜕皮周期的特定阶段观察到PTTH峰。在早期的成人发展，PTTH滴度的日节律的波动注意。五龄上半期血淋巴中也有少量PTTH。我们接下来测量了用于PTTH滴度测定的相同血淋巴样品中的蜕皮类固醇滴度，以关联PTTH和蜕皮类固醇的滴度变化模式。蜕皮激素的释放与PTTH的释放在时间和数量上都密切相关，这强烈表明PTTH在控制前胸腺活动中起着至关重要的作用。从这两种激素的动态变化来看，PTTH对前胸腺的作用具有急性和延迟的双重性。以游走延迟为指标的PTTH抗体注射效果表明，5龄初幼虫血淋巴中低滴度的PTTH也对前胸腺有一定的作用，并探讨了PTTH分泌的调控机制。光-暗周期的相移导致PTTH峰在时间上的移动，表明PTTH释放被调节在光-暗周期的特定时相发生。当第2天的5龄幼虫饥饿，血淋巴PTTH滴度下降，再喂养，迅速增加，表明PTTH释放在早期的5龄是受营养条件。