Regulation of vitellogenesis in ticks and purification of vitellogenesis inducing factor.

本文研究了软蜱、鸟嘴鸟和斑点鸟卵黄蛋白的生物合成及其激素调节。本研究首先从刚产下卵子中提纯卵黄蛋白(VN)，并对卵黄蛋白(VN)和卵黄蛋白前体VN的血淋巴前体卵黄蛋白(VG)进行纯化和鉴定。我们证明VN和VG是一种与血红蛋白和脂类非共价结合的结合磷酸化糖蛋白，分子大小约为600kD，由6个多肽组成。VG在脂肪体中合成，分泌到血淋巴中，以VN的形式积聚到发育中的卵母细胞中。VN由6个与VG不同(较小)的多肽组成。脂肪体内的VG合成主要是通过充血的刺激来激活的。血餐后，VG首先在充血后第2天出现在血淋巴中，并在血淋巴中增加到很高的浓度(最大值为60，Mugl，MUL)。我们已经尝试通过使用PR…来生产一种无激素的扁虱更多的生态新世来研究激素对VG合成的诱导。我们不能成功地生产出这些动物，但我们知道，在较低剂量(低于100杯/刻度)时，前驱虫对这种动物没有影响，而在较高剂量(超过150杯/刻度)时，对这种扁虱有毒性。但我们发现，合成拟除虫菊酯中的一种氯氰菊酯(Cym)对未充血(交配和处女)的成年雌性，甚至对未充血的雄虫和若虫都有积极的诱导VG合成和卵巢发育的作用。经Cym处理的未充血雌蜂产生VG并发育卵巢(但卵数较少)。这意味着，如果给予适当的体液条件，未充血的雌性有能力产生VG。我们将几种天然保幼激素(JH)和JH类似物(JHA)应用于未充血的雌性，但不能获得卵黄发生的积极效果。因此，我们认为JH不参与充血后VG合成的诱导过程。从神经激活型拟除虫菊酯(Cym)可以诱导卵黄原蛋白合成这一事实出发，通过一些结扎实验，我们发现联神经节(SYG)具有诱导脂肪体VG合成的因子。我们显示，从未充血的雌性动物身上收集的合神经节提取物处理的未充血的雌性动物产生的VG浓度显著高于扁虱林格处理的动物。我们对卵黄发生诱导因子(VIF)进行了纯化，结果表明VIF是一种多肽。较少

Biosynthesis of yolk protein and its hormonal regulation were investigated in the soft tick, Ornithodoros mouvata and Ornithodoros parkeri. We first purified and characterized yolkk protein, vitellin (Vn), and the hemolymph precursor of Vn, vitellogenein (Vg) from newly laid eggs and hemolymph of the tick, respectively. we demonstrated Vn and Vg are a conjugated phospho-glycoprotein associated non-covalently with haem and lipid, which molecular size is about 600 kD as native and is composed 6 polypeptides. Vg is synthesized in the fat body, secreted into hemolymph and accumulated into the developing oocytes as Vn. Vn is composed of 6 polypeptides differnt (more smaller) from that of Vg. Vg synthesis in the fat body is primarily activated by the stimulation of engorgement. After blood meal Vg appear in the hemolymph first on day 2 after engorgement and increased to very high concentration in the hemolymph (maximum 60, mugl, mul). We have tried to produce a hormone free ticks by using pr … More ecocene to study hormonal induction of Vg synthesis. We could- not produce those animals successfully, but 'we knew that precocene has no effect in lower doses (less than 100 mug/tick) and toxic in higher doses (more than 150 mug/tick) in this species of tick. But we found that one of synthetic pyrethroid, cypermethrin (CyM) has a positive effect to induce Vg synthesis and ovarian development in unengorged (both mated and virgin) adult females, and also even unengorged males and nymphs. CyM treated unengorged females produced Vg and developed ovary (but fewer eggs). This meant that unengorged females have ability to produce Vg if given a proper humoral conditions. We applied several natural juvenile hormones (JH) and JH analogs (JHA) on unengorged females, but we could not get positive effects for vitellogenesis. Therefore we concluded JH is not involved in the course of Vg synthesis induction after engorgement. From the fact that nerve activating pyrethroid, CyM, can induce vitelogenin synthesis, and from some ligation experiments we showed synganglion (SyG) has a factor which induces Vg synthesis in the fat body. We showed unengorged females treated with extract of synganglions collected from unengorged females produced Vg in significantly higher concentration than tick Ringer treated animals. We tried to purify this vitellogenesis inducing factor (VIF) and showed VIF is a polypeptids. Less