Attribution: Please use this identifier to share, cite, or link to this item: http://hdl.handle.net/10625/49792
Title: Mechanisms of sodium extrusion in isolated mitochondria-rich cells of the freshwater mussel Lasmigona costata after copper exposure
Authors: Nogueira, L S
Wood, C M
Bianchini, A
Gillis, P L
Keywords: CARBONIC ANHYDRASE
NA,K-ATPASE
BIVALVE
FISH CULTURE
SODIUM
COPPER
CONTAMINATION
SODIUM-POTASSIUM EXCHANGING ATPASE
Date: 2011
Citation: Nogueira, L. S., Wood, C. M., Bianchini, A., & Gillis, P. L. (2011). Mechanisms of sodium extrusion in isolated mitochondria-rich cells of the freshwater mussel Lasmigona costata after copper exposure. Proceedings of the IV Workshop e I Simpósio de Ecotoxicologia.
Abstract: Gill tissues in aquatic animals are composed of various cell types, each with specific functions such as respiration, excretion, acid-base balance and ionic regulation. In the bivalves, the gill is the main route of contaminant uptake and metals can be absorbed through specific transporters in cell membranes. Among the gill cells, mitochondria-rich cells (MRCs) are considered to be the primary sites responsible for iron transport. In order to determine the mechanisms of sodium extrusion in MRCs after copper exposure, gill cells from Lasmigona costata were isolated and layered on a discontinuous Percoll gradient. The pavement cells (PCVs) and MRCs populations were confirmed by a specific mitochondrial dye (DASPEI) and Na, K-ATPase activity. It is the first time at literature that isolated fill cells from freshwater mussels are identified in two different populations and used in toxicological experiments. MRCs were then exposed to a range of copper concentrations environmentally relevant (5, 10 and 20 ug/L) for 3 hours. Copper accumulation increased in all copper exposures. In contrast, the sodium content did not change in low exposures and decreased significantly when cells were exposed to high copper concentrations. To further explore this result, both sodium and copper were measured after specific pharmacological blockade of Na, K-ATPase and carbonic anhydrase enzymes. Carbonic anhydrase inhibition suggest that sodium and copper uptake mechanisms are not dependent on a supply of protons and intracellular increase of both ions might be associated to blocked of Na extrusion via Na/HCO3-. The inhibition of Na, K-ATPase by ouabain also resulted in an increase in sodium and copper content in the MRCs. This enzyme is responsible for sodium extrusion from the cell, and the results suggest that it is also a route for copper extrusion.
URI: http://hdl.handle.net/10625/49792
Project Number: 104519
Project Title: International Research Chairs Initiative (IRCI)
Access Restriction: Due to copyright restrictions the full text of this research output is not available in the IDRC Digital Library or by request from the IDRC Library. / Compte tenu des restrictions relatives au droit d`auteur, le texte intégral de cet extrant de recherche n`est pas accessible dans la Bibliothèque numérique du CRDI, et il n`est pas possible d`en faire la demande à la Bibliothèque du CRDI.
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