Nutrient limitation results in juvenile hormone-mediated resorption of previtellogenic ovarian follicles in mosquitoes
Nutrient limitation results in juvenile hormone-mediated resorption of previtellogenic ovarian follicles in mosquitoes
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DOI：
10.1016/j.jinsphys.2011.06.002
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发表时间：
2011-09-01
影响因子：
2.2
通讯作者：
Noriega, Fernando G.
中科院分区：
文献类型：
--
作者：
Clifton, Mark E.;Noriega, Fernando G.
保幼激素（OH）是埃及伊蚊雌蚊卵黄发生前期发育的一种中枢激素调节因子。JH水平在羽化时较低，在成虫羽化后的第一天增加。这种JH的初始上升对于女性生殖成熟至关重要。在前胚成熟完成后，蚊子进入“停滞状态”，在此期间，JH合成以较慢的速度继续，卵巢的进一步发育受到抑制，直到吸血。通过研究保幼激素、卵泡吸收与营养之间的关系，探讨保幼激素对卵泡发育的影响。对于埃及人，我们能够定义JH在端粒形成前静息阶段的关键作用。休眠期蚊子的卵泡吸收率取决于营养质量。单独饮水可使卵泡吸收率在羽化后第7天达到20%以上。相反，喂食20%蔗糖溶液导致再吸收在整个实验期间保持低于5%。喂食3%蔗糖的蚊子表现出介于水和20%蔗糖之间的再吸收率，并且在羽化后第7天仅达到10%。卵泡吸收与JH水平有关。从JH来源（咽侧体）分离的结扎的蚊子显示出与类似年龄的饥饿蚊子（16%）相当的再吸收增加。应用甲氧普烯后，结扎大鼠的吸收率降低至6%。甲氧普烯的应用也足以防止饥饿48小时的完整蚊子的吸收（14%饥饿对4%饥饿与甲氧普烯）。此外，活性半胱天冬酶被定位于再吸收卵泡，表明凋亡细胞死亡机制是负责卵泡再吸收在pretellogogenic休息阶段。两者合计，这些结果表明，JH介导的生殖权衡在休息阶段的蚊子在响应营养。爱思唯尔有限公司出版
Juvenile hormone OH) is a central hormonal regulator of previtellogenic development in female Aedes aegypti mosquitoes. JH levels are low at eclosion and increase during the first day after adult emergence. This initial rise in JH is essential for female reproductive maturation. After previtellogenic maturation is complete, the mosquito enters a 'state-of-arrest' during which JH synthesis continues at a slower pace and further ovary development is repressed until a blood meal is taken. By examining the relationships between juvenile hormone, follicular resorption and nutrition in A. aegypti, we were able to define a critical role of JH during the previtellogenic resting stage. The rate of follicular resorption in resting stage mosquitoes is dependent on nutritional quality. Feeding water alone caused the rate of follicular resorption to reach over 20% by day 7 after emergence. Conversely, feeding a 20% sucrose solution caused resorption to remain below 5% during the entire experimental period. Mosquitoes fed 3% sucrose show rates of resorption intermediate between water and 20% sucrose and only reached 10% by day 7 after emergence. Follicular resorption is related to JH levels. Ligated abdomens separated from a source of JH (the corpora allata) showed an increase in resorption comparable to similarly aged starved mosquitoes (16%). Resorption in ligated abdomens was reduced to 6% by application of methoprene. The application of methoprene was also sufficient to prevent resorption in intact mosquitoes starved for 48 h (14% starved vs. 4% starved with methoprene). Additionally, active caspases were localized to resorbing follicles indicating that an apoptotic cell-death mechanism is responsible for follicular resorption during the previtellogenic resting stage. Taken together, these results indicate that JH mediates reproductive trade-offs in resting stage mosquitoes in response to nutrition. Published by Elsevier Ltd.