Zur Physiologie der Alkaloidbildung bei Claviceps-Arten

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Summary Our strain pepty 695 of Claviceps purpurea produces clavines, ergometrine and ergotoxine alkaloids under submerged conditions. Clearly a “balanced phase”, “transition phase“ and “maintenance phase” of growth and metabolism according to Borrow et al. can be distinguished. Claviceps paspali strain Li 342 follows the fermentation pattern No.2 according to Taber. There was practically no increase in the total alkaloid yield of the ergotoxine strain after the addition of tryptophan or analogues to the preculture or fermentation medium. D, L-4- methyl-tryptophan caused an inhibition of the alkaloid formation. The metabolism of tryptophan under different conditions in C. paspali was investigated. Protein-bound tryptophan is used for alkaloid synthesis. There is a remarkable difference in the utilization of tryptophan in the pre culture and fermentation mycelium. Most of the administered tryptophan is converted during the alkaloid formation phase equally to alkaloids and to 2,3-dihydroxybenzoic acid. The metabolism of valine, leucine and proline in the ergotoxine strain was investigated during different phases of development. A considerable protein turnover during the alkaloid production phase was observed like in other strains. Inhibitors of protein synthesis did not affect the formation of the peptide portion of ergotoxine alkaloids. These results seems to indicate that the synthesis of the peptide portion is an non-ribosomal process. Also the “ergoline synthetase“ is not inhibited by adding cycloheximide to C. paspali cultures.