High Laccase2 expression is likely involved in the formation of specific cuticular structures during soldier differentiation of the termite Reticulitermes speratus
High Laccase2 expression is likely involved in the formation of specific cuticular structures during soldier differentiation of the termite Reticulitermes speratus
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DOI：
10.1016/j.asd.2013.08.003
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发表时间：
2013-11-01
影响因子：
2
通讯作者：
Maekawa, Kiyoto
中科院分区：
文献类型：
--
作者：
Masuoka, Yudai;Miyazaki, Satoshi;Maekawa, Kiyoto
白蚁士兵在形态上专门用于群体防御。分析士兵分化机制对于理解白蚁社会的建立非常重要。士兵在入伍前阶段与工人有所不同，并且具有良好的硬化和着色角质层。这些特征对于巢穴防御很重要，并且可能是由士兵特有的角质层晒黑机制引起的。导致角质层晒黑的分子机制尚未阐明。 Laccase2 (Lac2) 在昆虫的这一过程中发挥着重要作用，我们假设 Lac2 表达可能参与士兵特异性角质层晒黑。我们观察了散白蚁 (Reticulitermes speratus) 的内部和外部头部角质层的变化，并比较了三种蜕皮（工蚁、工蚁和兵蚁）的 Lac2 表达模式。对头部角质层颜色的定量分析表明，入伍前士兵蜕皮时的颜色特性比其他两种蜕皮中的变化更明显。组织学观察表明，士兵头部的外角质层比工人和前士兵头部的外角质层厚得多，在蜕皮之前或之后进行晒黑，并且比其他蜕皮的时间点更早着色。最后，仅在入伍士兵蜕皮之前和之后观察到明显较高的 Lac2 表达水平。这些结果表明，在士兵分化过程中，外表皮中发生了特定的角质层形成，并且在士兵蜕皮期间Lac2的高水平表达与士兵特异性角质层晒黑有关。我们推测 Lac2 表达调节机制的进化对于获得士兵特异性角质层非常重要。 (C) 2013 Elsevier Ltd. 保留所有权利。
Termite soldiers are morphologically specialized for colony defense. Analysis of the mechanisms of soldier differentiation is important for understanding the establishment of termite societies. Soldiers differentiate from workers through a presoldier stage and have well-sclerotized and pigmented cuticles. These characteristics are important for nest defense and are likely to be caused by soldier-specific mechanisms of cuticular tanning. The molecular mechanisms leading to cuticular tanning have not been elucidated. Laccase2 (Lac2) plays important roles in this process in insects, and we hypothesized that Lac2 expression may be involved in soldier-specific cuticular tanning. We observed inner and outer head cuticle changes and compared the Lac2 expression patterns among three molts (worker worker, worker presoldier and presoldier soldier) in the termite Reticulitermes speratus. Quantitative analyses of head cuticle colors showed that the color properties changed more conspicuously in presoldier soldier molts than in the other two molts. Histological observations showed that the exocuticles of soldier heads were substantially thicker than those of worker and presoldier heads, underwent tanning before or just after ecdysis, and were pigmented at earlier time points than other molts. Finally, markedly higher Lac2 expression levels were observed just before and after ecdysis only in the presoldier soldier molt. These results suggest that specific cuticular formation occurs in the exocuticles during soldier differentiation, and that the high level of Lac2 expression during the presoldier soldier molt is related to soldier-specific cuticular tanning. We speculate that evolution of the regulatory mechanisms of Lac2 expression were important for the acquisition of soldier-specific cuticles. (C) 2013 Elsevier Ltd. All rights reserved.