家蝇的卵黄发生及其激素调节

用5—15%SDS-PAGE分析表明,家蝇Musce domestica viaina卵黄蛋白由三个亚基组成,其亚基分子量分别为58KD、50KD、48KD.火箭免疫电泳的结果表明,脂肪体、血淋巴和卵巢内卵黄原蛋白的变化具有密切的相关性,卵黄原蛋白在体内最早出现在羽化后30小时左右,然后迅速增加,在羽化后48小时,脂肪体和血淋巴中卵黄原蛋白含量达到最大值,卵巢开始沉积卵黄蛋白在羽化后30小时,到产卵前达到最大值,脂肪体在离体培养条件下,通过测定³H-亮氨酸掺入卵黄原蛋白的量,对不同发育时期家蝇脂肪体合成卵黄原蛋白的能力及激素的调节作用进行了研究,结果表明,羽化12小时后,合成能力迅速上升,48小时时形成高峰,60小时后迅速下跌直至产卵,其合成能力一直维持在低水平,产卵后合成能力又迅速回升,激素处理结果表明,保幼激素可以促进卵黄发生前期和后期家蝇脂肪体的卵黄原蛋白合成,20-羟基蜕皮酮可以大幅度促进卵黄发生期家蝇脂肪体的卵黄原蛋白合成.当二种激素共同处理时,对卵黄发生前期和卵黄发生期的家蝇脂肪体有协同促进作用,而对卵黄发生后期的脂肪体没有这种作用.本文还对家蝇卵黄发生过程中脂肪体、血淋巴和卵巢三者之间的关系及家蝇卵黄发生的激素调节进行了讨论.

VITELLOGENESIS AND ITS HORMONAL CONTROL IN THE HOUSEFLY MUSCA DOMESTICA VICINA

Through SDS-PAGE analysis, the yolk protein of Musca domestica vicina was found to contain three subunits with molecular weights of 58KD, 50kD and 48KD. The vitellogenin (Vg) and total protein contents of the fat body, hemolymph and ovary of the female flies after emergence were studied and the results showed their close relationship. Generally, Vg appeared in hemolymph at 30 hours after emergence and reached a peak at 48 hours. The Vg content of fat body during vitellogenesis showed a similar pattern of fluctuation. Yolk deposition in the ovarp began at 30 hours after emergence, increased sharply in the vitellogenic stage and reached the peak before oviposition. Synthesis of Vg in the fat body and its control by hormones were studied at different stages of the flies by incubation in vitro with Grace medium containing 3H-leucine. The results showed that the rate of Vg synthesis was very low in previtello-tgenic stage, increased sharply at 12 hours after emergence, rose to maximum at 48 hours and decreased abruptly at 60 hours, keeping in low level in the postvitellogenic stage. After oviposi-tion the capacity for Vg synthesis increased immediately. It was shown that Vg synthesis could be stimulated by adding juvenile hormone III into the incubation medium at the pre- and post-bitellogenic stages and. by adding 20-hydroxyecdysone to a greater extent at the vitellogenic sta-ge. Vg synthesis could be stimulated by adding both juvenile hormone III and 20-hydroxyecdy-sone at previtellogenic or vitellogenic stage, but not at postvitellogenic stage. The hormonal regulation of vitellogenesis in the housefly is discussed.