Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan.
Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan.
Sci Rep. 2017 Jan 31;7:41651. doi: 10.1038/srep41651.
Diapause, a programmed developmental arrest, is common in insects, enabling them to survive adverse seasons. It is well established that pupal diapause is regulated by ecdysteroids secreted by the prothoracic glands (PGs), with cessation of ecdysteroid secretion after pupal ecdysis leading to pupal diapause. A major factor regulating the gland activity is prothoracicotropic hormone (PTTH) secreted from the brain. In our previous study, we demonstrated that the cessation of PTTH release after pupal ecdysis resulted in the inactivation of the PGs, leading to pupal diapause in the cabbage army moth Mamestra brassicae. Here we show that a neuropeptide myosuppressin also contributes to the inactivation of PGs at the initiation of diapause. Myosuppressin suppresses PTTH-stimulated activation of the PGs in vitro. Concentrations of myosuppressin in the hemolymph after pupal ecdysis are higher in diapause pupae than in nondiapause pupae.
滞育是一种程序性的发育停滞，在昆虫中很常见，使它们能够在不利的季节中生存。人们已经充分认识到，蛹滞育是由前胸腺（PGs）分泌的蜕皮激素调节的，蛹蜕皮后停止分泌蜕皮激素会导致蛹滞育。调节腺体活动的一个主要因素是来自大脑的前胸腺激素（PTTH）。在我们之前的研究中，我们证明了蛹蜕皮后 PTTH 释放的停止导致 PGs 的失活，从而导致小菜蛾 Mamestra brassicae 的蛹滞育。在这里，我们表明一种神经肽肌抑制素也有助于在滞育开始时 PGs 的失活。肌抑制素在体外抑制 PTTH 刺激的 PG 激活。在蛹蜕皮后，血淋巴中的肌抑制素浓度在滞育蛹中高于非滞育蛹。
