Development of a sensitive ELISA for the determination of microcystins in algae.
Journal
Journal of agricultural and food chemistry
Journal Volume
50
Journal Issue
15
Start Page
4176-4182
ISSN
0021-8561
Date Issued
2002-07-17
Author(s)
Abstract
Polyclonal antibodies for microcystin-leucine-arginine (MCYST-LR) were generated from rabbits after immunizing the animals with MCYST-LR conjugated with gamma-globulin. A competitive direct enzyme-linked immunosorbent assay (cdELISA) and a competitive indirect ELISA (ciELISA) were used for the characterization of the antibodies and for analysis of the toxin in algal cultures and dietary supplements. The concentrations causing 50% inhibition (IC(50)) of binding of MCYST-horseradish peroxidase (MCYST-HRP) to the solid-phase antibodies by MCYST-LR, MCYST-arginine-arginine variant (MCYST-RR), MCYST-tyrosine-arginine variant (MCYST-YR), and nodularin (NODLN) in the cdELISA were found to be 0.10, 0.12, 0.14, and 0.20 ng/mL, respectively. In the presence of algae matrix, the detection limit is less than 10 ppb. The overall analytical recovery of MCYST-LR (25 to 500 ng/g) added to the algal dietary supplements and then extracted with 0.1 M ammonium bicarbonate in the cdELISA was found to be 83.7%. Analysis of MCYSTs in algal cultures and dietary supplements showed that six of eleven cultures produce MCYSTs, and five of the algal cultures were not MCYST producers. Eight of eleven tested commercial algal dietary supplements contained MCYSTs at a level lower than 100 ppb. The presence of MCYST-LR in the Microcystis aeruginosa culture was confirmed by high-performance liquid chromatography.
Publisher
American Chemical Society (ACS)
Type
journal article