title: A comparison of in vivo and in vitro assays to assess the toxicity of algal blooms.
abstract: The toxicity of purified microcystin-LR (MC-LR) and algal material collected during the winter and summer seasons (2005/2006) from the Hartebeespoort dam, South Africa, was investigated using the enzyme-linked immunosorbent assay (ELISA), mouse bioassay, catfish primary hepatocytes (in vitro assay) and protein phosphatase inhibition (PPi) assays. Microcystis aeruginosa, known producer of microcystins, was the dominant cyanobacteria present in the water samples. Exceptionally high cell numbers per millilitre were observed, especially with the summer samples (approximately 1.442 x 10(8)cells/ml), indicating a severe algal bloom in the dam. The toxin concentration as detected by ELISA and PPi assay in the winter and summer extracts was at least 1000 times more than the provisional guideline value (1 microg/l) set by the World Health Organization (WHO) for MC-LR in drinking water. Hepatotoxic effects and death of mice were observed after dosing with the summer extracts, while no hepatotoxic effects were observed with winter extracts. The EC(50) values obtained after exposure of the catfish primary hepatocytes for 72h to MC-LR, winter and summer extracts was about 0.091, 0.053 and 0.014 mg/l, respectively. Similar toxicity results were obtained when the mouse bioassay and primary hepatocytes were used.
authors.affiliation: Division of Toxicology, Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort 0110, South Africa.
authors.forename: Mxolisi
authors.initials: M
authors.lastname: Masango
authors.forename: Jan
authors.initials: J
authors.lastname: Myburgh
authors.forename: Christo
authors.initials: C
authors.lastname: Botha
authors.forename: Leonie
authors.initials: L
authors.lastname: Labuschagne
authors.forename: Dharmarai
authors.initials: D
authors.lastname: Naicker
mesh_terms: D000818:Animals; D001681:Biological Assay; D002397:Catfishes; D002478:Cells, Cultured; D000458:Cyanobacteria / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D056890:Eukaryota / Q000737:chemistry*; D005068:Eutrophication; D022781:Hepatocytes / Q000187:drug effects; D008297:Male; D051379:Mice; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D018675:Toxicity Tests
chemical_list: D004791:Enzyme Inhibitors; D054648:Protein Phosphatase 2