David Daniela Dantas, de Assis Leonardo Vinícius Monteiro, Moraes Maria Nathalia, Zanotto Flávia Pinheiro, Castrucci Ana Maria de Lauro
Laboratory of Comparative Physiology of Pigmentation, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
Center of Brain, Behavior and Metabolism, Institute of Neurobiology, Lübeck University, Lübeck, Germany.
Front Physiol. 2022 Jun 21;13:903060. doi: 10.3389/fphys.2022.903060. eCollection 2022.
Environmental cues synchronize endogenous rhythms of many physiological processes such as hormone synthesis and secretion. Little is known about the diurnal pattern of hormones and gene expression of the molt cycle. We aimed to investigate in the eyestalk and hepatopancreas of premolt and intermolt the following parameters: 1) the diurnal expression of the ecdysteroid receptor isoforms, and the molt inhibiting hormone 2) the diurnal hemolymph ecdysteroid and melatonin levels; and 3) melatonin effects on the transcripts of the above-mentioned genes in intermolt . Ecdysteroid levels were higher in the premolt than the intermolt animals at all time points evaluated (ZTs). Premolt crabs displayed a variation of ecdysteroid concentration between time points, with a reduction at ZT17. No difference in the melatonin level was seen in either molt stage or between stages. In the eyestalk of intermolt animals, expression oscillated, with a peak at ZT9, and premolt crabs have a reduction at ZT9; transcripts did not vary along 24 h in either molt stage. Moreover, the evaluated eyestalk genes were more expressed at ZT9 in the intermolt than the premolt crabs. In the hepatopancreas, expression showed a peak at ZT9 in premolt crabs. Exogenous melatonin (10 mol/animal) reduced the expression of both genes in the eyestalk at ZT17. In the hepatopancreas, melatonin markedly increased the expression of the gene at ZT9. Taken altogether, our results are pioneer in demonstrating the daily oscillation of gene expression associated to molt cycle stages, as well as the daily ecdysteroid and melatonin levels and the remarkable influence of melatonin on the molt cycle of .
环境线索使许多生理过程的内源性节律同步，如激素合成和分泌。关于蜕皮周期中激素的昼夜模式和基因表达知之甚少。我们旨在研究蜕皮前期和蜕皮间期的眼柄和肝胰腺中的以下参数：1）蜕皮类固醇受体亚型和蜕皮抑制激素的昼夜表达；2）血淋巴中蜕皮类固醇和褪黑素的昼夜水平；3）褪黑素对蜕皮间期上述基因转录本的影响。在所有评估的时间点（ Zeitgeber时间，ZTs），蜕皮前期动物的蜕皮类固醇水平均高于蜕皮间期动物。蜕皮前期的螃蟹在不同时间点的蜕皮类固醇浓度存在变化，在ZT17时有所降低。在两个蜕皮阶段或不同阶段之间，褪黑素水平均未观察到差异。在蜕皮间期动物的眼柄中，基因表达呈振荡变化，在ZT9时达到峰值，而蜕皮前期的螃蟹在ZT9时表达降低；在两个蜕皮阶段，转录本在24小时内均无变化。此外，在蜕皮间期，所评估的眼柄基因在ZT9时的表达高于蜕皮前期的螃蟹。在肝胰腺中，蜕皮前期螃蟹的基因表达在ZT9时达到峰值。外源性褪黑素（10 μmol/只动物）在ZT17时降低了眼柄中两个基因的表达。在肝胰腺中，褪黑素在ZT9时显著增加了该基因的表达。综上所述，我们的结果首次证明了与蜕皮周期阶段相关的基因表达的每日振荡，以及每日的蜕皮类固醇和褪黑素水平，以及褪黑素对[物种名称未提及]蜕皮周期的显著影响。
