Investigation of Ammonia Transport Pathways in the Anal Papillae of Larval Aedes Aegypti Mosquito

The anal papillae of Aedes aegypti larvae, are important sites of ammonia/ammonium excretion. They express three putative ammonia (NH3/NH4+) transporters, Rhesus proteins AeRh50-1, AeRh50-2 and AeAmt. Ammonium concentration gradients were measured adjacent to the anal papillae using scanning ion-selective electrode technique (SIET). Results suggest that the ionomotive pumps V-type H+ ATPase (VA) and Na+/K+ ATPase (NKA) as well as cation / H+ exchanger, isoform 3 (NHE3) participate in ammonia excretion at the anal papillae. VA is involved in ammonia trapping at the exterior unstirred layer of the anal papillae, while basal NKA and apical NHE3 facilitate the transport of NH4+. Quantitative RT-PCR analysis revealed differential abundances of AeRh-2 and Amt in the anal papillae relative to the abundance of AeRh50-1. In presence of HEA both Rhs were down regulated but Amt was up regulated. It is the conclusion of this study that these transporters work in consortium to regulate ammonia.