Meeting Abstract
We investigated the role of cation chloride cotransporters (CCCs) in osmoregulation by larvae of the yellow fever mosquito, Aedes aegypti. Three putative Na-coupled CCCs are expressed in larval tissues. Prior qPCR studies showed that the VectorBase genes AAEL006180 (tentatively named aeCCC1) and AAEL009888 (aeCCC2) are more highly expressed in larval Malpighian tubules compared to anal papillae. In contrast, AAEL009886 (aeCCC3) is more highly expressed in larval anal papillae compared to Malpighian tubules. To evaluate the physiological role of aeCCC1 and aeCCC2, we used RNAi to reduce expression of each transporter. We exposed first instar larvae to aeCCC1 or aeCCC2 dsRNAs. Negative controls were no dsRNA or a dsRNA without sequence homology to A. aegypti genes. Hemolymph cations of fourth instar larvae were measured by cation chromatography. Larvae exposed to aeCCC1 or aeCCC2 dsRNA had up to five-fold increases in mean hemolymph total ammonia (ammonia and ammonium) levels compared to negative controls. Hemolymph potassium was reduced by approximately 15% in response to aeCCC1 dsRNA, with no consistent change in hemolymph sodium. In contrast, hemolymph sodium was increased by approximately 20% in response to aeCCC2 dsRNA exposure, with no consistent change in hemolymph potassium. These findings suggest physiological roles for aeCCC1 and aeCCC2 in osmoregulation and ammonia balance of larval mosquitoes.
