Early events in adult eye development of the moth, Manduca sexta
Early events in adult eye development of the moth, Manduca sexta
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DOI：
10.1016/j.jinsphys.2005.12.006
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发表时间：
2006-05-01
影响因子：
2.2
通讯作者：
Champlin, David T.
中科院分区：
文献类型：
--
作者：
Allee, J. Paul;Pelletier, Chris L.;Champlin, David T.
天蛾的眼成虫盘是在幼虫末龄早期从成虫眼原基形成的，它由幼虫头囊表皮完全分化的细胞组成。伴随着幼虫表皮程序的下调，原基中激活了作为蛹定型标志物的广泛表达。然后细胞从角质层分离，向内折叠，并开始高水平增殖，产生倒置的眼成虫盘。在最后幼虫龄的第一天开始的这些事件和其他事件似乎标志着变态的开始。对于昆虫变态起始的内分泌控制知之甚少。在此期间，血淋巴中的保幼激素（JH）滴度下降至较低水平，JH 的存在足以抑制培养的眼原基的发育。然而，通过持久的 JH 模拟物治疗将 JH 维持在体内高水平，对眼成象盘发育的早期步骤没有明显影响。我们在内分泌控制变态的背景下讨论我们的发现。烟草天蛾（也许还有许多昆虫物种）变态的开始似乎涉及通过一种未知的、营养依赖的激素因子来克服 JH 抑制。 (c) 2006 Elsevier Ltd. 保留所有权利。
The eye imaginal disc of Manduca sexta is created early in the final larval instar from the adult eye primordium, which is composed of fully differentiated cells of the larval head capsule epidermis. Concomitant with the down-regulation of the larval epidermal program, expression of broad, a marker of pupal commitment, is activated in the primordium. The cells then detach from the cuticle, fold inward, and begin to proliferate at high levels to produce the inverted, eye imaginal disc. These and other events that begin on the first day of the final larval instar appear to mark the initiation of metamorphosis. Little is known about the endocrine control of the initiation of metamorphosis in any insect. The hemolymph titer of juvenile hormone (JH) declines to low levels during this period and the presence of JH is sufficient to repress development in cultured eye primordia. However, maintenance of JH at high levels in vivo by treatment with long-lasting JH mimics has no apparent effect on early steps in eye imaginal disc development. We discuss our findings in the context of the endocrine control of metamorphosis. The initiation of metamorphosis in Manduca, and perhaps a wide range of insect species, appears to involve the overcoming of JH repression by an unidentified, nutrient-dependent, hormonal factor. (c) 2006 Elsevier Ltd. All rights reserved.