Radioimmunoassays for the separate and quantitative determination of the peptide ergot alkaloids ergotamine and ergocristine were developed. The alkaloids were coupled covalently to bovine serum albumin and antibodies were raised in rabbits. 3H-labelled tracers were used. The antibodies exhibited high specificity and affinity towards these alkaloids [Ka = 0.15 × 109l/mol (ergocristine); Ka = 1.32 × 109 l/mol (ergotamine)]. Simple lysergic acid derivatives and clavines did not cross react. The measuring range was between 3.5-86 pmol (2-50 ng) of ergotamine and 0.8-33 pmol (0.5-20 ng) of ergocristine. With this assay the alkaloid distribution in sclerotia of Claviceps purpurea (Fries) Tulasne was determined, and the time course of alkaloid formation in parasitic Claviceps cultures was followed. Alkaloid rich sclerotia were selected from natural sources and successfully used in the establishment of high alkaloid yielding parasitic strains.
Claviceps purpurea - Radioimmunoassay - Peptide Ergot Alkaloids - Distribution of Alkaloids - Kinetics of Alkaloid Formation - Screening Techniques.
