Research Areas: Salt and Water Regulation and Ammonia Excretion in Aquatic Insects
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.
Durant A.C., Donini A. 2018 Evidence that Rh proteins in the anal papillae of the freshwater mosquito Aedes aegypti are involved in the regulation of acid base balance in elevated salt and ammonia environments. Journal of Experimental Biology 221
Durant A.C., Donini A. 2019 Development of Aedes aegypti (Diptera, Culicidae) mosquito larvae in high ammonia sewage in septic tanks causes alterations in ammonia excretion, ammonia transporter expression and osmoregulation. Scientific Reports (In press).
Nowghani F., Chen C.C., Jonusaite S., Watson-Leung T., Kelly S.P., Donini A. 2019 Impact of salt-contaminated freshwater on osmoregulation and tracheal gill function in nymphs of the mayfly Hexagenia rigida. Aquatic Toxicology 211:92-104.
Durant A.C., Donini A. 2018 Ammonia excretion in an osmoregulatory syncytium is facilitated by AeAmt2, a novel ammonia transporter in Aedes aegypti larvae. Frontiers in Physiology, Invertebrate Physiology March 20, 2018.
Durant A.C., Celis-Salgado M.P., Ezatollahpour S., Yan N.D., Arnott S.E., Donini A. 2018 Ca2+ levels in Daphnia hemolymph may explain occurrences of daphniid species along recent Ca gradients in Canadian soft-water lakes. Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology 218:8-15.
Yerushalmi G., Misyura L., MacMillan H. A., Donini A. 2018 Functional plasticity of the gut and the Malpighian tubules underlies cold acclimation and mitigates cold-induced hyperkalemia in Drosophila melanogaster Journal of Experimental Biology
Nowghani F., Jonusaite S., Watson-Leung T., Donini A., Kelly S.P. 2017 Strategies of ionoregulation in the freshwater nymph of the mayfly (Hexagenia rigida). Journal of Experimental Biology 220:3997-4006. [Article Hi-lighted on Cover of Issue]
MacMillan H.A., Yerushalmi, G., Jonusaite, S., Kelly, S.P., Donini, A. 2017 Thermal acclimation mitigates paracellular leak from the Drosophila gut. Scientific Reports 7 Article 8807.
Misyura, L., Yerushalmi, G., Donini, A. 2017 A mosquito entomoglyceroporin, Aedes aegypti AQP5 participates in water transport across the Malpighian tubules of larvae. Journal of Experimental Biology 220:3536-3544.
Jonusaite, S., Kelly, S.P., Donini, A. 2017 Identification of the septate junction protein gliotactin in the mosquito, Aedes aegypti: evidence for a role in increased paracellular permeability in larvae. Journal of Experimental Biology 220:2354-2363.
Durant, A.C., Chasiotis, H., Misyura, L., Donini, A. 2017 Aedes aegypti Rhesus glycoproteins contribute to ammonia excretion by larval anal papillae. Journal of Experimental Biology 220:588-596.
Jonusaite, S., Donini, A., Kelly, S.P. 2017 Salinity alters snakeskin and mesh transcript abundance and permeability in midgut and Malpighian tubules of larval mosquito, Aedes aegypti Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology 205: 58-67.
Akhter, H., Misyura, L., Bui, P., Donini, A. 2017 Salinity responsive aquaporins in the anal papillae of the larval mosquito, Aedes aegypti. Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology 203:144-151