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Divalent metal (Ca, Cd, Mn, Zn) uptake and interactions in the aquatic insect Hydropsyche sparna.
MedLine Citation:
PMID:  22496295     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Despite their ecological importance and prevalent use as ecological indicators, the trace element physiology of aquatic insects remains poorly studied. Understanding divalent metal transport processes at the water-insect interface is important because these metals may be essential (e.g. Ca), essential and potentially toxic (e.g. Zn) or non-essential and toxic (e.g. Cd). We measured accumulation kinetics of Zn and Cd across dissolved concentrations ranging 4 orders of magnitude and examined interactions with Ca and Mn in the caddisfly Hydropsyche sparna. Here, we provide evidence for at least two transport systems for both Zn and Cd, the first of which operates at concentrations below 0.8 μmol l(-1) (and is fully saturable for Zn). We observed no signs of saturation of a second lower affinity transport system at concentrations up to 8.9 μmol l(-1) Cd and 15.3 μmol l(-1) Zn. In competition studies at 0.6 μmol l(-1) Zn and Cd, the presence of Cd slowed Zn accumulation by 35% while Cd was unaffected by Zn. At extreme concentrations (listed above), Cd accumulation was unaffected by the presence of Zn whereas Zn accumulation rates were reduced by 58%. Increasing Ca from 31.1 μmol l(-1) to 1.35 mmol l(-1) resulted in only modest decreases in Cd and Zn uptake. Mn decreased adsorption of Cd and Zn to the integument but not internalization. The L-type Ca(2+) channel blockers verapamil and nifedipine and the plasma membrane Ca(2+)-ATPase inhibitor carboxyeosin had no influence on Ca, Cd or Zn accumulation rates, while Ruthenium Red, a Ca(2+)-ATPase inhibitor, significantly decreased the accumulation of all three in a concentration-dependent manner.
Authors:
Monica D Poteat; Mauricio Díaz-Jaramillo; David B Buchwalter
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  215     ISSN:  1477-9145     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-04-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1575-83     Citation Subset:  IM    
Affiliation:
Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA.
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