Ergot alkaloids

Giant colonies prepared from sclerotia ofClaviceps purpurea form in many cases sharply bounded purple-pigmented sectors not originating from the colony centres, the so-called “late sectors”. Similar sectors are found in giant colonies obtained after an isolation of individual conidia from the mycelium of the white portion of the sectored giant colony. These results, supported by literature data, indicate that ergot sclerotia are commonly homokaryotic and that phenotypically different sectors result from a mutation during growth of the giant colony. In a parasitic culture on rye some mutation-derived purple isolates are reversed to form sclerotia with alkaloid level identical to that of the parent strain while some retain their mutated character, exhibiting hence a significantly reduced alkaloid production.