Expression and Function of an Animal MEP/Amt Ammonia Transporter , AeAmt2 in the Larvae of the Mosquito, Aedes aegypti

The mosquito Aedes aegypti is the primary vector of zika, dengue and chikungunya viruses. Larvae are commonly found in freshwater habitats; however, it was shown that ammonia rich septic tanks in the Caribbean also serve as habitats for larval development and adult emergence which can explain the prevalence of disease during the dry season. Since ammonia (NH 3 /NH 4 + ) is toxic to animals an understanding of how the larvae of A. aegypti can survive in septic tanks is important. Our previous studies showed that A. aegypti possess two Rhesus‐like proteins, AeRh50‐1 , AeRh50‐2 , and a MEP/Amt transporter, AeAmt1. Those studies demonstrated that these ammonia transporters are expressed in the anal papillae, finger like sacs that surround the anus and actively transport ions, where they play a role in ammonia excretion. This study reports on a fourth ammonia transporter in A. aegypti , a MEP/Amt transporter, AeAmt2 . The AeAmt2 is expressed in the anal papillae epithelium where it is co‐localized with the V‐type H + ‐ATPase on the apical (water facing) membrane. To elucidate the function of AeAmt2 in anal papillae, larvae were treated for double stranded RNA knockdown of AeAmt2 and ammonia fluxes were recorded at the anal papillae with the scanning ion selective electrode technique (SIET). The effects of AeAmt2 knockdown on larvae were assessed by tracking survival over time and measuring the ammonia and proton (pH) levels of the hemolymph with ion selective microelectrodes. Ammonia excretion is a vital physiological process in all animals and this study further elucidates ammonia excretion mechanisms of larval disease vector mosquitoes, which is of particular significance given their ability to inhabit areas of high environmental ammonia. Support or Funding Information National Sciences and Engineering Research Council of Canada