Research Areas: Ion–regulatory Physiology of Aquatic Dipteran Larvae
Ion and water balance of internal fluids is essential to the survival of all animals and is achieved through the actions of ion transporting epithelia that are regulated by neuroendocrine factors. Aquatic animals face a particular challenge in this respect because they live immersed in water that is often significantly different in composition compared to their internal fluids. In freshwater, these animals lose ions and gain water to the hypo-osmotic habitat and therefore they regulate ion and water levels by conserving ions and excreting the excess water. However, these animals must also be able to respond to alterations in their habitat composition because freshwater environments are subject to industrial, agricultural and sewage effluents as well as severe climatic events such as heavy rainfall with flooding, or drought with evaporation. In northern regions where road salt is utilized for de-icing in winter, salinity levels of freshwater habitats can suddenly and severely increase during spring runoff. In addition, in these regions sodium and chloride levels have been steadily increasing over the long-term.
Many ecologically important insects as well as insect vectors of human pathogens inhabit these areas (e.g. midges, mayflies, mosquitoes). In tropical regions, a freshwater mosquito Aedes aegypti, the vector of yellow fever, dengue and chikungunya virus, has recently been found breeding in salinated water and in septic tanks that are high in ammonia, suggesting that this freshwater species is adapting to the changes in their habitat composition. Our research studies the ion transport mechanisms, and their regulation, in organs of these insects which ultimately determine their ability to successfully inhabit water of varying composition. Despite identification of relevant organs responsible for ion and water balance in certain insects like mosquito and midge larvae, the molecular and physiological mechanisms at work in these organs are poorly understood, as is their neural and endocrine regulation. Results of our research will contribute to an understanding of insect population distribution related to environmental salinity levels and other pollutants like ammonia. Continued use of road-salt can drive freshwater species to adapt to the increased salinity and may also ultimately lead to invasion of inland waters by salt-tolerant mosquito and midge species which normally inhabit coastal areas.
Jonusaite, S., Donini, A., Kelly, S.P. 2015 Occluding junctions of invertebrate epithelia. Journal of Comparative Physiology B, Biochemical, Systemic and Environmental Physiology (Published Online October 28, 2015 DOI 10.1007/s00360-015-0937-1)
Ruiz-Sanchez, E., O’Donnell, M.J., Donini, A. 2015. Secretion of Na+, K+ and fluid by the Malpighian (renal) tubule of the larval cabbage looper Tichoplusia ni (Lepidoptera Noctuidae). Journal of Insect Physiology 82: 92-98.
MacMillan, H.A., Ferguson, L.V., Nicolai, A., Donini, A., Staples, J.F., Sinclair, B.J. 2015. Parallel ionoregulatory adjustments underlie phenotypic plasticity and evolution of Drosophila cold tolerance. The Journal of Experimental Biology 218: 423-432.
Robertson, L., Chasiotis, H., Galperin, V., Donini, A. 2014. Allatostatin A-like immunoreactivity in the nervous system and gut of the larval midge, Chironomus riparius (Meigen): Modulation of hindgut motility, rectal K+ transport and implications for exposure to salinity. The Journal of Experimental Biology 217: 3815-3822.
Robertson, L., Donini, A., Lange, A.B. 2014. K+ absorption by locust gut and inhibition of ileal K+ and water transport by FGLamide allatostatins. The Journal of Experimental Biology 217: 3377-3385.
Jonusaite, S., Kelly, S.P., Donini, A. 2013. Tissue specific ionomotive enzyme activity and K+ reabsorption reveal the rectum as an important ionoregulatory organ in larval Chironomous riparius exposed to varying salinity. The Journal of Experimental Biology 216: 3637-3648.
Ionescu, A., Donini, A. 2012. AedesCAPA-PVK-1 displays diuretic and dose dependent antidiuretic potential in the larval mosquito Aedes aegypti (Liverpool). Journal of Insect Physiology 58(10):1299-1306.
Marusalin, J., Matier, B., Rheault, M.R., Donini, A. 2012. Aquaporin homologs and water transport in the anal papillae of the larval mosquito, Aedes aegypti. Journal of Comparative Physiology B, Biochemical, Systemic and Environmental Physiology 182 (8): 1047-1056.
Weihrauch, D., Donini, A., O’Donnell, M.J. 2012. Ammonia transport by terrestrial and aquatic insects. Journal of Insect Physiology 58(4):473-487.
Del Duca, O., Nasirian, A., Galperin, V., Donini, A. 2011. Pharmacological characterisation of apical Na+ and Cl- transport mechanisms of the anal papillae in the larval mosquito Aedes aegypti. The Journal of Experimental Biology 214 (23):3992-3999.