Department of Biological Sciences, Faculty of Science, Kanagawa University, Kanagawa, Japan.
Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo, Japan.
Front Endocrinol (Lausanne). 2020 Jul 28;11:475. doi: 10.3389/fendo.2020.00475. eCollection 2020.
Physiological functions of juvenile hormone (JH) and molting hormone have been demonstrated in insects. JH, molting hormone and their mimics (insect growth regulators, IGRs) show endocrine-disrupting effects not only on target pest insects but also on other arthropod species such as crustaceans. However, little is known about the endocrine-disrupting effects of IGRs on benthic crustaceans. In this study, laboratory experiments were conducted to investigate effects of representative innate JH in crustaceans (methyl farnesoate, MF) and molting hormone (20-hydroxyecdysone, 20E, active form of ecdysteroid) on larval stages of the kuruma prawn , which is a decapod crustacean living in warm seawater. Larval development of kuruma prawn progresses in the order of nauplius, zoea, mysis, and then post-larvae with molting and metamorphosis, but it is unknown whether both MF and 20E have crucial roles in metamorphosis and molting of this species. Treatments of either MF or 20E on shrimp larvae were attempted at each developmental stage and those effects were validated. In terms of EC values between mortality and metamorphosis, there were apparent differences in the transition from nauplius to zoea (MF: 7.67 and 0.12 μM; 20E: 3.84 and 0.06 μM in survival and metamorphic rates, respectively). In contrast, EC values in MF and 20E treatments showed high consistency in the transitions between zoea to mysis (EC values for survival; MF: 1.25 and 20E: 0.22 μM), and mysis to post-larvae (EC values for survival; MF: 0.65 and 20E: 0.46 μM). These data suggest that nauplius has strong resistance against exposure to MF and 20E. Moreover, both chemicals induced high mortality triggered by the disruption of molting associated with metamorphosis. To our knowledge, this is the first experimental evidence that investigates physiological functions of MF and 20E in the larval stages of kuruma prawn, shedding light on not only ecotoxicological impacts of IGRs released into nature, but also endocrine mechanisms underlying larval development with metamorphosis in benthic decapod crustaceans.
昆虫的保幼激素（JH）和蜕皮激素的生理功能已经得到证实。JH、蜕皮激素及其类似物（昆虫生长调节剂，IGR）不仅对靶标害虫而且对甲壳类等其他节肢动物物种具有内分泌干扰作用。然而，对于 IGR 对底栖甲壳类动物的内分泌干扰作用知之甚少。在这项研究中，进行了实验室实验，以研究代表甲壳类动物的内源性 JH（法呢酯，MF）和蜕皮激素（20-羟基蜕皮酮，20E，蜕皮甾酮的活性形式）对生活在暖海水中的糠虾幼虫阶段的影响。糠虾的幼虫发育顺序为无节幼体、幼体、幼体，然后是幼体，经历蜕皮和变态，但尚不清楚 MF 和 20E 是否在该物种的变态和蜕皮中具有关键作用。在每个发育阶段尝试用 MF 或 20E 处理虾幼虫，并验证了这些作用。就死亡率和变态之间的 EC 值而言，从无节幼体到幼体的转变（MF：7.67 和 0.12 μM；20E：3.84 和 0.06 μM，在存活率和变态率方面）有明显差异。相比之下，MF 和 20E 处理中的 EC 值在幼体到幼体的转变中表现出高度一致性（EC 值用于生存；MF：1.25 和 20E：0.22 μM），以及幼体到幼体的转变（EC 值用于生存；MF：0.65 和 20E：0.46 μM）。这些数据表明，无节幼体对 MF 和 20E 的暴露具有很强的抵抗力。此外，这两种化学物质都诱导了由于与变态相关的蜕皮而导致的高死亡率。据我们所知，这是第一个实验证据，证明 MF 和 20E 在糠虾幼虫阶段的生理功能，不仅为释放到自然界中的 IGR 的生态毒理学影响提供了线索，还为底栖十足甲壳类动物的幼虫发育与变态的内分泌机制提供了线索。
