Ecdysteroid hormone titer and its relationship to vitellogenesis in the soft tick, Ornithodoros moubata (Acari: Argasidae)
Ecdysteroid hormone titer and its relationship to vitellogenesis in the soft tick, Ornithodoros moubata (Acari: Argasidae)
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DOI：
10.1016/j.ygcen.2006.09.007
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发表时间：
2007-02-01
影响因子：
2.7
通讯作者：
Taylor, DeMar
中科院分区：
文献类型：
--
作者：
Ogihara, Kazumasa;Horigane, Mari;Taylor, DeMar
血餐是大多数argasid雌性蜱繁殖所必需的。血粉似乎刺激后端的器官产生脂肪体刺激因子（FSF），该因子被认为是蜕皮类固醇，以诱导卵黄蛋白原（Vg）的合成。本研究通过测定卵母细胞的卵裂球蛋白（Vg）和蜕皮激素的滴度，同时观察交配雌虫和未交配雌虫的卵母细胞发育和产卵情况，探讨了卵黄发生与蜕皮激素的关系。交配雌虫饱食后第10天开始产卵，并持续40-50天，而未交配雌虫则不发生卵成熟和产卵。血淋巴中的Vg滴度在充血后第6天达到峰值，随后在交配的雌性中下降。有趣的是，Vg合成发生和卵巢发育进展到早期卵黄发生卵母细胞的发展，但卵母细胞成熟和产卵没有发生在处女女性。局部应用蜕皮甾类激素可诱导已进食的处女雌虫产卵，表明蜕皮甾类激素可诱导产卵。充血后20天的蜕皮类固醇浓度显示交配雌性全身提取物中有几个峰，但处女雌性提取物中没有峰。在仅交配的雌性血淋巴中，蜕皮激素滴度在饱食后第4天和第6天出现两个峰值，随后出现全身蜕皮激素的早期峰值。此外，交配雌虫生殖组织中的蜕皮甾体随着卵巢的发育而增加，这种增加与整个身体的后期高峰相吻合。这些观察结果表明，蜕皮激素的生理性升高加速Vg合成，并可能诱导卵成熟，刺激产卵在喂养交配的雌鸟moubata。(c)2006年爱思唯尔公司All rights reserved.
A blood meal is required for reproduction in most argasid female ticks. The blood meal appears to stimulate an organ in the posterior end to produce a fat body stimulating factor (FSF), which is thought to be an ecdysteroid, to induce vitellogenin (Vg) synthesis. In this study, the relationship of vitellogenesis and ecdysteroids was investigated by measuring Vg and ecdysteroid titers while observing oocyte development and oviposition in mated and virgin females. Oviposition occurred from day 10 after engorgement in mated females and continued up to 40-50 days, whereas egg maturation and oviposition did not occur in virgin females. Vg titers in the hemolymph peaked on day 6 after engorgement and subsequently declined in mated females. Interestingly, Vg synthesis occurred and ovarian development progressed to the development of early vitellogenic oocytes in virgin females but oocyte maturation and oviposition did not occur. Topical application of eedysteroids induced oviposition in fed virgin females indicating that ecdysteroids may induce oviposition. Concentrations of ecdysteroids for 20 days after engorgement revealed several peaks in mated female whole body extracts, but no peaks in virgin female extracts. In the hemolymph of only mated females, ecdysteroid titers showed two peaks that followed the early peak of ecclysteroids in the whole body on day 4 and 6 after engorgement. In addition, ecdysteroids in the reproductive tissues increased with the development of the ovary in mated females and this increase coincided with the latter peaks of the whole body. These observations indicate that physiological elevation of ecdysteroids accelerate Vg synthesis, and may induce egg maturation and stimulate oviposition in fed mated Ornithodoros moubata females. (c) 2006 Elsevier Inc. All rights reserved.