Salt and Water Regulation and Ammonia Excretion in Aquatic Insects
Current Research Themes:
The Physiology of Life in High Ammonia
Ammonia is found as gaseous NH3 or in ionic form as NH4+and is a toxic product of protein metabolism in animals. Terrestrial animals have evolved mechanisms to convert ammonia into less toxic waste (e.g. urea, uric acid) for periodic elimination, but aquatic animals excrete ammonia directly into their surroundings. We study the mechanisms of ammonia excretion in aquatic insect larvae and currently we are focussing on the mosquito, Aedes aegypti. This is because A. aegypti inhabit ammonia-rich septic tanks in regions of the world where they transmit disease. During dry season, these non-traditional habitats allow for the persistence of disease transmission.
How does salinity affect the ion and osmoregulatory physiology of freshwater insects?
Salination of freshwater is a major global problem. In coastal areas, sea levels are predicted to rise leading to salt contamination and in temperate regions rising salt levels in freshwater are linked to road salt and other anthropogenic activities. These bodies of water are important habitats for aquatic animals that have evolved to live in freshwater. Their physiology is tailored to eliminating excess water while sequestering salts. Salination challenges these physiological mechanisms and we are interested in understanding how these animals deal with salination. We do this by studying expression and regulation of salt (ion) transporters, water transporters (aquaporins) and proteins that make up structures (septate junctions) that regulate the passage of solutes between cells.