D. Gröger

Zur Physiologie der Alkaloidbildung bei Claviceps-Arten

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.

A blocked mutant ofClaviceps purpurea accumulating chanoclavine-I-aldehyde

An alkaloid-blocked mutant ofClaviceps purpurea was isolated from a strain which produces ergotoxine alkaloids. The mutant accumulates chanoclavine-I and the corresponding aldehyde. It lacks the ability to form tetracyclic ergolines.

Über den Einbau von Anthranilsäure in Peganin

Anthranilic acid-(14COOH) was administered to rooted leaves ofAdhatoda vasica Nees. The isolated alkaloid peganine = vasicine was degraded according to the method ofSpäth andHikawitz (Figure). The anthranilic acid obtained showed the same specific radioactivity as the alkaloid. Therefore anthranilic acid must be regarded as a direct precursor of peganine inA. vasica Nees.

Zur Biosynthese der C9–10-Einheit der Indolalkaloide

After administration of various C2-compounds as well as leucine-2-14C toCatharanthus roseus shoots and glycine-2-14C toStrychnos nux vomica plants no specific incorporation into the non-tryptophan C9–10 moiety of indole alkaloids was observed. The results indicate that glycine-2-14C is transformed into serine and is incorporated via tryptophan into strychnine.

Tetramethylputrescine from young plants of Ruellia rosea

Abstract Tetramethylputrescine was isolated from the roots and aerial parts of Ruellia rosea . The compound was characterized by MS, 13 C-NMR-spectroscopy and comparison with a synthetic specimen.

Über den Einbau von Asparaginsäure in Peganin

Aspartate-3-C14 (XIII) was administered to young plants ofAdhatoda vasica Nees. After a feeding period of 1 or 2 days, the isolated alkaloid peganine (=vasicine) (I) was degraded. The distribution of the radioactivity in the anthranilic acid (II) and glycine (XIV) obtained has been determined (Figure). Most of the radioactivity (∼80%) was localized in the glycine corresponding to the positions 1 and 2 of peganine. More radioactivity was recovered from position 2 of the alkaloid than from position 1. The labelling pattern is discussed. The results indicate either that aspartate or a closely related compound is an immediate precursor of peganine.

Biosynthese der Mutterkornalkaloide. Einbau von Chanoclavin-I in Ergolin-Derivate

The reaction sequence tryptophan →chanoclavine-I → agroclavine → elymoclavine →lysergic acid derivatives was demonstrated in Claviceps. Incorporation of chanoclavine-I into ergoline derivatives ranged up to 40 per cent. No conversion of elymoclavine or agroclavine into chanoclavine-I could be demonstrated.

Über die Biosynthese der Mutterkornalkaloide: Vergleich von zwei möglichen Zwischenprodukten

Bei zwei verschiedenenClaviceps-Stämmen werden die Einbauraten von markiertem 4-Dimethylallyl-tryptophan (II) und l- (β-Indolyl) -2-amino-5-methylhexen- (4) (I) in die Mutterkornalkaloide miteinander und mit denen des Tryptophans verglichen. II wird besser verwertet als I, jedoch schlechter als Tryptophan. Es wird untersucht, welche Faktoren die Verwertung der Verbindungen beeinflussen. Eine klare Entscheidung, ob I oder II Zwischenstufen der Ergolin-Biosynthese sind, kann nicht getroffen werden.

Biosynthese der Mutterkornalkaloide. Biogenetische Beziehungen zwischen Clavinen und Lysergsäure-Derivaten

Using Claviceps paspalum strain Li 189 and various tritium-labeled clavine alkaloids, it was demonstrated that agroclavine and elymoclavine but not penniclavine are precursors of lysergic acid derivatives. There was some incorporation of lysergene, lysergole and isolysergole, the latter two giving rise predominantly to the lysergic acid derivatives with the same configuration at carbon 8. However, these compounds cannot be considered as intermediate on the main pathway of lysergic acid formation, since their incorporations were 10 times lower than that of elymoclavine. The pathway of conversion of elymoclavine into lysergic acid derivatives is discussed.