Summary: | 碩士 === 國立臺灣師範大學 === 生命科學研究所 === 100 === Aquaporins (AQPs) are integral membrane proteins that facilitate water transport across cell membrane. In addition, some type of AQPs was also found to facilitate diffusion of CO2, glycerol, NH3, and urea. Recently, in vitro studies with Xenopus oocytes showed that AQP8 is able to facilitate CO2/NH3 diffusion. However, in vivo study was lacking to support AQP’s function in CO2/NH3 transport. In this study, AQP8AA were identified in the gills and larval skin of zebrafish. Triple in situ hybridization / immunohistochemistry localized AQP8AA in two subtypes of ionocytes (HR cells and NaR cells). The protein and mRNA expressions of AQP8aa were induced by high-ammonia acclimation (10 mM NH4+) but not hypercapnia water acclimation (1% CO2). Using morpholino oligonucleotides to knockdown AQP8AA protein expression and a scanning ion-selective technique (SIET) to analyze carbonic acid (H+) and NH4+ transport at the skin ionocytes of larvae, this study suggests that AQP8AA facilitates CO2/NH3 transport in the skin ionocytes.
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