Molting is an essential biological process occurring characteristic times throughout the life cycle of holometabolous insects. However, it is not clear how insects determine the direction of molting to remain status quo or to initiate metamorphosis. To explore the functional factors that determine the direction of molts, liquid chromatography-mass spectrometry was used to identify the molecules involved in larval and metamorphic molting, and the differentially expressed proteins (DEPs) were compared in the two processes. There were 321 and 1140 DEPs identified in larval and metamorphic molting process, respectively. Bioinformatics analyses show that the amino sugar pathway was up-regulated in both processes. The up-regulated protease contributed to the metamorphosis. In addition, several proteins with different expression patterns in larval-larval and larval-pupal transitions, including Endochitinase, GRIM-19 (Genes associated with retinoid-IFN-induced mortality-19), IDE (Insulin-degrading enzyme), Sorcin (Soluble resistance related calcium binding protein), OBP (Odorant-binding protein-2 precursor), TRAP1(Tumor necrosis factor receptor associated protein-1), etc., were further identified by parallel reaction monitoring, which may play diverse functions in larval-larval and larval-pupal transitions. These results provide a proteomic insight into molecules involved in larval and metamorphic molts, and will likely improve the current understanding of determination of direction of molts.

中文翻译：

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昆虫幼虫和变质蜕皮的无标记定量蛋白质组学分析

蜕皮是在全代谢昆虫整个生命周期中发生的一个重要的生物过程。然而，目前尚不清楚昆虫如何确定蜕皮方向以保持现状或开始变态。为探索决定蜕皮方向的功能因素，采用液相色谱-质谱联用技术鉴定了参与幼虫和变质蜕皮的分子，并比较了两个过程中的差异表达蛋白（DEPs）。在幼虫和变质蜕皮过程中分别鉴定出 321 和 1140 个 DEP。生物信息学分析表明，氨基糖途径在这两个过程中均上调。上调的蛋白酶有助于变态。此外，几种在幼虫-幼虫和幼虫-蛹转变中具有不同表达模式的蛋白质，包括内切多丁酶、GRIM-19（与类视黄醇-干扰素诱导的死亡率相关的基因-19）、IDE（胰岛素降解酶）、Sorcin（可溶性抗性相关的钙结合蛋白）、OBP（气味结合蛋白-2前体）、TRAP1（肿瘤坏死因子受体相关蛋白-1）等，通过平行反应监测进一步鉴定，可能在幼虫-幼虫和幼虫-蛹的转变。这些结果提供了对参与幼虫和变质蜕皮的分子的蛋白质组学见解，并且可能会提高目前对确定蜕皮方向的理解。通过平行反应进一步鉴定IDE（胰岛素降解酶）、Sorcin（可溶性抗性相关钙结合蛋白）、OBP（气味结合蛋白-2前体）、TRAP1（肿瘤坏死因子受体相关蛋白-1）等监测，可能在幼虫-幼虫和幼虫-蛹的转变中发挥不同的功能。这些结果提供了对参与幼虫和变质蜕皮的分子的蛋白质组学见解，并且可能会提高目前对确定蜕皮方向的理解。通过平行反应进一步鉴定IDE（胰岛素降解酶）、Sorcin（可溶性抗性相关钙结合蛋白）、OBP（气味结合蛋白-2前体）、TRAP1（肿瘤坏死因子受体相关蛋白-1）等监测，可能在幼虫-幼虫和幼虫-蛹的转变中发挥不同的功能。这些结果提供了对参与幼虫和变质蜕皮的分子的蛋白质组学见解，并且可能会提高目前对确定蜕皮方向的理解。