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Intraclonal variability in Daphnia acetylcholinesterase activity: The implications for its applicability as a biomarker
Author(s) -
Printes Liane Biehl,
Callaghan Amanda
Publication year - 2003
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/02-424
Subject(s) - acetylcholinesterase , aché , daphnia , enzyme assay , daphnia magna , biology , toxicity , enzyme , toxicology , biochemistry , chemistry , ecology , zooplankton , organic chemistry
The relationship between individual growth and acetylcholinesterase (AChE) activity was evaluated for Daphnia magna . Analysis on the influence of two different culture media on baseline AChE activity was performed with Daphnia similis . The results indicated an inverse relationship between D. magna body length and AChE activity. An increase in total protein, which was not proportional to an increase in the rate of the substrate hydrolysis (Δ absorbance/min), seems to be the reason for this inverse size versus AChE activity relationship. Therefore, toxicants such as phenobarbital, which affect protein and size but not AChE activity directly, have an overall affect on AChE activity. In contrast, the AChE inhibitor parathion altered AChE activity but not protein. Culture medium also had a significant affect on AChE activity in D. similis . Changes in total protein seem to be the main reason for the variations in baseline AChE activity in Daphnia observed in the different evaluations performed in this work. Therefore, AChE activity in Daphnia must be interpreted carefully, and variations related to changes in total protein must be taken into account when applying this enzyme as a biomarker in biological monitoring.