| Abstract
| - Polyclonal antibodies for microcystin-leucine-arginine (MCYST-LR) were generated from rabbits afterimmunizing the animals with MCYST-LR conjugated with γ-globulin. A competitive direct enzyme-linked immunosorbent assay (cdELISA) and a competitive indirect ELISA (ciELISA) were used forthe characterization of the antibodies and for analysis of the toxin in algal cultures and dietarysupplements. The concentrations causing 50% inhibition (IC50) of binding of MCYST-horseradishperoxidase (MCYST-HRP) to the solid-phase antibodies by MCYST-LR, MCYST-arginine-argininevariant (MCYST-RR), MCYST-tyrosine-arginine variant (MCYST-YR), and nodularin (NODLN) in thecdELISA were found to be 0.10, 0.12, 0.14, and 0.20 ng/mL, respectively. In the presence of algaematrix, the detection limit is less than 10 ppb. The overall analytical recovery of MCYST-LR (25 to500 ng/g) added to the algal dietary supplements and then extracted with 0.1 M ammonium bicarbonatein the cdELISA was found to be 83.7%. Analysis of MCYSTs in algal cultures and dietary supplementsshowed that six of eleven cultures produce MCYSTs, and five of the algal cultures were not MCYSTproducers. Eight of eleven tested commercial algal dietary supplements contained MCYSTs at alevel lower than 100 ppb. The presence of MCYST-LR in the Microcystisaeruginosa culture wasconfirmed by high-performance liquid chromatography. Keywords: Enzyme-linked immunosorbent assay; ELISA; microcystins; antibodies
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