Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany
Colorado State University, Fort Collins, CO 80523, USA.
J Exp Biol. 2018 Nov 5;221(Pt 21):jeb187492. doi: 10.1242/jeb.187492.
Mechanistic target of rapamymcin (mTOR) is a highly conserved protein kinase that controls cellular protein synthesis and energy homeostasis. We hypothesize that mTOR integrates intrinsic signals (moulting hormones) and extrinsic signals (thermal stress) to regulate moulting and growth in decapod crustaceans. The effects of temperature on survival, moulting and mRNA levels of mTOR signalling genes (, , , and ) and neuropeptides ( and ) were quantified in juvenile Crabs at different moult stages (12, 19 or 26 days postmoult) were transferred from ambient temperature (∼15°C) to temperatures between 5 and 30°C for up to 14 days. Survival was 97-100% from 5 to 20°C, but none survived at 25 or 30°C. Moult stage progression accelerated from 5 to 15°C, but did not accelerate further at 20°C. In eyestalk ganglia, , and mRNA levels decreased with increasing temperatures. and mRNA levels were lowest in the eyestalk ganglia of mid-premoult animals at 20°C. In the Y-organ, mRNA levels decreased with increasing temperature and increased during premoult, and were positively correlated with haemolymph ecdysteroid titre. In the heart, moult stage had no effect on mTOR signalling gene mRNA levels; only , and mRNA levels were higher in intermoult animals at 10°C. These data suggest that temperature compensation of neuropeptide and mTOR signalling gene expression in the eyestalk ganglia and Y-organ contributes to regulate moulting in the 10 to 20°C range. The limited warm compensation in the heart may contribute to mortality at temperatures above 20°C.
雷帕霉素靶蛋白（mTOR）是一种高度保守的蛋白激酶，它控制着细胞的蛋白质合成和能量稳态。我们假设 mTOR 整合内在信号（蜕皮激素）和外在信号（热应激）来调节十足目甲壳动物的蜕皮和生长。在不同蜕皮阶段（蜕皮后 12、19 或 26 天）的幼年 蟹中，测定了温度对存活率、蜕皮和 mTOR 信号基因（、、、和）和神经肽（和）mRNA 水平的影响。将 12、19 或 26 天的幼虫从环境温度（约 15°C）转移到 5 至 30°C 的温度下，持续 14 天。在 5 至 20°C 之间，存活率为 97-100%，但在 25 或 30°C 时没有存活。蜕皮阶段在 5 至 15°C 时加速，但在 20°C 时不再加速。在眼柄神经节中，、和 mRNA 水平随温度升高而降低。在 20°C 时，中蜕皮动物的眼柄神经节中 和 mRNA 水平最低。在 Y 器官中，mRNA 水平随温度升高而降低，在蜕皮前增加，与血淋巴蜕皮甾酮水平呈正相关。在心脏中，蜕皮阶段对 mTOR 信号基因 mRNA 水平没有影响；只有 10°C 时，间蜕皮动物的 、和 mRNA 水平更高。这些数据表明，眼柄神经节和 Y 器官中神经肽和 mTOR 信号基因表达的温度补偿有助于调节 10 至 20°C 范围内的蜕皮。心脏中的温暖补偿有限可能导致温度高于 20°C 时的死亡率。
