U.S.-Czechoslovakia Research on Developmental Timing in Drosophila

昆虫幼虫中再生组织的存在抑制了 内分泌系统启动蜕皮或变态 直到再生完成，但性质的 抑制信号未知。类似的增长效应 内分泌系统的外周组织被认为是 导致了幼虫寿命的显著延长， 与持续生长的成虫盘有关， 果蝇的花盘过度生长突变体。布莱恩特博士 建议通过调查来测试后一种想法， 这些突变体的内分泌他将完成他的测量 突变型幼虫和野生型幼虫中蜕皮类固醇滴度的 含有再生的成虫盘，他将确定 C-27和C-28之间的比例是否有变化 蜕皮激素用体外培养的方法培养成虫的盘和环 腺体，他将调查是否减少蜕皮激素滴度 他在突变体中记录的是由于 胚盘对蜕皮激素的利用或降解 或抑制环状腺释放蜕皮激素。的 初步结果已经表明，环腺输出减少 在变种人的后面布莱恩特博士将调查 影响是环腺自主或间接影响，由于 正在生长的成虫盘的存在。的效果 内分泌系统将通过测量生产 促前胸腺激素的分泌。 %%% 这项研究将提供新的证据，一个重要的，但很少 在控制发育的事件链中， 昆虫的时间

The presence of regenerating tissue in a larval insect inhibits the endocrine system from initiating molting or metamorphosis until the regeneration is complete, but the nature of the inhibitory signal is unknown. A similar effect of growing peripheral tissues on the endocrine system is thought to be responsible for the dramatically prolonged larval life which is associated with continuously growing imaginal discs in lethal imaginal-disc overgrowth mutants of Drosophila. Dr. Bryant proposes to test the latter idea by investigating the endocrinology of these mutants. He will complete his measurements of ecdysteroid titers in mutant larvae and on wild type larvae containing regenerating imaginal disc, and he will determine whether there are changes in the ratio between C-27 and C-28 ecdysteroids. Using in vitro culture of imaginal discs and ring glands, he will investigate whether the reduced ecdysteroid titer that he has documented in the mutants is due to increased utilization or degradation of ecdysteroids by the imaginal discs or to inhibition of ecdysteroid release by the ring gland. The preliminary results already show a reduction of ring gland output in tow of the mutants. Dr. Bryant will investigate whether such effects are ring gland autonomous or are indirect effects due to the presence of growing imaginal discs. The effect on the endocrine system will be investigated by measuring the production of prothoracicotropic hormone by mutant nervous systems. %%% This study will provide new evidence on an important but little understood link in the chain of events that control developmental timing in insects.