Enzyme-linked immunosorbent assay for microcystins in blue-green algal blooms.
A direct competitive enzyme-linked immunosorbent assay (ELISA) for the freshwater blue-green algal toxin microcystin (MCYST) in algae and water was developed. The assay involves coating anti-MCYST-variant leucine-arginine (LR) antibody to the ELISA plate and the use of MCYST-LR-peroxidase as the enzyme marker. The linear portion of the standard curve for MCYST in phosphate buffer containing saline (PBS) was 0.5-10.0 ng/mL (25-500 pg/assay). The minimum detection level for MCYST-LR was 0.20 ng/mL (10 pg/assay). Contaminated water could be directly used in the ELISA. The overall analytical recoveries for MCYST-LR added to water at levels of 1-20 ng/mL was 83.4%. For analysis of cellular MCYST, the toxin was first extracted from the algae with 0.1M ammonium bicarbonate, diluted with PBS to less than 0.5 mg dried algae/mL (less than 5.0 mg wet weight/mL) and directly used in the ELISA. C-18 reverse-phase Sep-Pak cartridges effectively adsorbed MCYST from the toxin-containing solutions. The toxin could be recovered from the cartridge by eluting with 60% methanol. Using this approach, an algae extract that was relatively free of MCYST was prepared and was used in a recovery study. The overall analytical recovery of MCYST added to the algae extract in the range of 0.25-20 ppm was 83% with a coefficient of variation of 11.9%. The detection limit for MCYST in dried algae was about 0.25-0.5 microgram/g (0.25-0.5 ppm) lyophilized algae sample. This method was applied for the analysis of several naturally occurring algal blooms. Limited samples were also analyzed for MYCST by liquid chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)
Chu
F S
FS
University of Wisconsin-Madison, Food Research Institute, Madison, WI.
Huang
X
X
Wei
R D
RD
D002853:Chromatography, Liquid; D000458:Cyanobacteria / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D007124:Immunoenzyme Techniques; D007202:Indicators and Reagents; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis*; D014118:Toxins, Biological / Q000032:analysis*; D014867:Water / Q000032:analysis
D007202:Indicators and Reagents; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D014118:Toxins, Biological; D014867:Water; C057862:cyanoginosin LR