Date of Award

Spring 5-7-2014

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Neuroscience

First Advisor

Christopher M. Gillen, PhD

Abstract

Aedes aegypti transmits yellow fever and dengue, two of the most devastating mosquito-borne arboviral diseases. To overcome mosquito resistance to insecticides, new insecticides can potentially be produced to target important physiological processes such as osmoregulation. We have identified three cation chloride cotransporter (CCC) proteins important for osmoregulation in the yellow fever mosquito, namely aeCCC1, aeCCC2 and aeCCC3. In this study, we measured the effects of different biological and environmental factors on the gene expression levels of these proteins, using qPCR. AeCCC1 was expressed moderately through all life stages of the mosquito. In adult female mosquitoes, aeCCC1 was expressed highest in the head and MTs whereas it is expressed only highest in MTs in larvae. In adults, aeCCC2 showed 200-fold higher expression in the hindgut than in other regions whereas larvae expressed highest aeCCC2 levels in MTs. AeCCC3 is expressed most highly in the anal papillae of larvae (about 6,000 times higher than MTs). And, exposure to 30% seawater decreased this expression. In contrast, aeCCC3 expression increased in MTs due to seawater exposure. In an effort to begin functional characterization of the aeCCCs, we also utilized cation chloride chromatography to study the hemolymph ion composition of larvae raised in 30% seawater compared to freshwater. We found higher Na+ and NH4+ levels in seawater-exposed larvae compared to freshwater controls. The different aeCCC gene expression patterns suggest that aeCCC1 might be a secretory cotransporter, while aeCCC2 and aeCCC3 might be both a secretory and an absorptive cotransporter, depending on developmental stage and salinity.

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