Document Detail


Mechanism of acute silver toxicity in the euryhaline copepod Acartia tonsa.
MedLine Citation:
PMID:  17374407     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Acute silver effects on whole-body ion regulation and Na(+),K(+)-ATPase activity were evaluated in the euryhaline copepod Acartia tonsa. Experiments were run at 20 degrees C, three different salinities (5, 15 and 30 ppt), in either the absence or the presence of food (diatom Thalassiosira weissflogii; 2 x 10(4)cells/mL). Standard static-renewal procedures were used. Copepods were acutely (48 h) exposed to silver (AgNO(3)) concentrations equivalent to the 48-h EC10 (dissolved Ag=3, 49, and 94 microg/L), 48-h EC30 (dissolved Ag=5, 71, and 125 microg/L) or 48-h EC50 (dissolved Ag=7, 83, and 173 microg/L) values in the absence of food or to the 48-h EC50 (dissolved Ag=35, 90, and 178 microg/L) values in the presence of food. These values were previously determined under the same experimental conditions at salinities 5, 15 and 30 ppt, respectively. Endpoints analyzed were whole-body ion concentrations (Na(+), Cl(-), and Mg(2+)) and Na(+),K(+)-ATPase activity. In starved copepods, lower whole-body Na(+) and Mg(2+) concentrations were observed in salinities 5 and 30 ppt, respectively. Also a higher whole-body Na(+),K(+)-ATPase activity was observed in all salinities tested. Data from fed copepods indicate that all these salinity effects were completely associated with starvation. Silver exposure induced a decrease in the whole-body Mg(2+) concentration in starved copepods in salinities 5 and 30 ppt and a Na(+),K(+)-ATPase inhibition in both starved and fed copepods in all salinities tested. Thus, food addition in the experimental media completely protected against silver effects on Mg(2+) concentration, but not against those on Na(+),K(+)-ATPase activity. In starved copepods, enzyme inhibition was dependent on silver concentration and a relationship between this parameter and mortality was observed in all salinities tested. Therefore, Na(+),K(+)-ATPase molecules seem to be a key site for acute silver toxicity in marine invertebrates, as reported for freshwater fish and crustaceans.
Authors:
Mariana S Pedroso; Grasiela L L Pinho; Sandra C Rodrigues; Adalto Bianchini
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-02-23
Journal Detail:
Title:  Aquatic toxicology (Amsterdam, Netherlands)     Volume:  82     ISSN:  0166-445X     ISO Abbreviation:  Aquat. Toxicol.     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-04-09     Completed Date:  2007-07-24     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8500246     Medline TA:  Aquat Toxicol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  173-80     Citation Subset:  IM    
Affiliation:
Programa de Pós-Graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Fundação Universidade Federal do Rio Grande, Av. Itália km 8, 96.201-900 Rio Grande, RS, Brazil.
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MeSH Terms
Descriptor/Qualifier:
Animal Feed
Animals
Chlorides / analysis
Copepoda / chemistry,  drug effects*,  enzymology
Environmental Exposure*
Ions / analysis
Magnesium / analysis
Seawater / analysis
Silver / analysis,  toxicity*
Sodium / analysis
Sodium-Potassium-Exchanging ATPase / analysis,  drug effects*,  metabolism
Time Factors
Toxicity Tests / veterinary
Water / analysis,  chemistry
Water Pollutants, Chemical / toxicity*
Chemical
Reg. No./Substance:
0/Chlorides; 0/Ions; 0/Water Pollutants, Chemical; 7439-95-4/Magnesium; 7440-22-4/Silver; 7440-23-5/Sodium; 7732-18-5/Water; EC 3.6.3.9/Sodium-Potassium-Exchanging ATPase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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