Functional association of epithelium isotocin receptor and adenylyl cyclase with seawater acidification in marine medaka

• Main Authors: Yi-An Chen, 陳怡安
• Other Authors: Ming-Yi Chou
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/48nqr6

碩士 === 國立臺灣大學 === 生命科學系 === 107 === Seawater acidification, a prior environmental perturbation, is resulted from accelerating seawater pCO2 levels due to the anthropogenic CO2 emissions. Various negative effects were proved in the living marine organisms by serious of hypercapnic-treated estimations. However, the physiological machinery regarding hormone response associates with adenylyl cyclases signaling pathways is still unclear in marine teleosts under acidic stress. In this study, marine medaka (Oryzias melastigma) was utilized to explore the effects of CO2-induced acidified seawater on the above responses. On one hand, isotocin receptor homolog (ITR2) was thought to be involved in differentiation and proliferation of epithelial ionocytes. In pH 7.6 treatment group, the transcriptional levels of ITR2 were up-regulated in the larvae and adult gills compared with the control (pH 8.1) counterpart. On the other hands, adenylyl cyclase isoform (ADCY5), an enzyme which can induce downstream ion-transport while catalyzes by the G protein-coupled receptors. In pH 7.6 treatment group, the transcriptional levels of ADCY5 in larvae increased significantly compared with the control (pH 8.1) ones. Moreover, ITR2 and ADCY5 were found to be localized predominantly on the basolateral and apical membrane of epithelium ionocytes, respectively, in adult gills and larval yolk sac. Furthermore, while the ITR2 and ADCY5 were both abolished, ionocyte-related transporters were downregulated, thus the proton secretion from the yolk sac skin was decreased significantly under pH 7.6 acidic condition. Consequently, epithelial ITR2 and ADCY5 play essential roles in acid-base homeostasis under acidic perturbations.