Mutational Biosynthesis in a Strain of Claviceps purpurea¹

Abstract

An alkaloid-blocked mutant of Claviceps purpurea was isolated from an ergotoxine producing strain. It accumulates chanoclavine-I and the corresponding aldehyde. The formation of agroclavine is blocked in this particular strain. By feeding with appropriate intermediates (tetracyclic ergolines) the mutant produces the normal alkaloidal spectrum of the parent strain. Surprisingly, after supplementation with agroclavine, ergosine is synthesized. lntroduction Blocked mutants are useful tools to elucidate the biosynthetic pathways of secondary metabolites. They are also important for a genetic investigation. Well known examples are the studies of tetracycline biosynthesis with Strepto-' Dedicated to Professor Dr. Drs. h. C. K.

Further studies on cell-free biosynthesis of ergotamine in Claviceps purpurea

“…Shake cultures were grown at 24+ I°C at 240 rev./min. For preparation of the inoculum the procedure of [7] was adopted. Alkaloid production was achieved in a sucrose/ammonium citrate-containing medium, NL833 [4].…”

A New Strain of Claviceps purpurea Accumulating Tetracyclic Clavine Alkaloids

“…Fermentation experiments in shake culture were carried out at 24°C at 240 rpm on a VEB Fanal rotary shaker. The inoculation procedure was done according to [13]. Also the replacement experimerits were performed as it was described earlier [131. d-Lyscrgic acid (4 mg125 ml culture broth) was administered to washed mycehum.…”

“…The quantitative determinations of the various components of the alkaloid mixtures were done after TLC separation according to [13].…”

High-production mutant Claviceps purpurea 59 accumulating secoclavines

“…These efforts have yielded, e.g., auxotrophic mutants of C. purpurea [1][2][3] including a tryptophan-dependent mutant [3], sporulating mutants of Claviceps paspali [4], high-production mutants of Claviceps fusiformis [5] and mutants of C. purpurea with an altered spectrum of produced alkaloids [6]. Improvement of strain C. purpurea Pepty 695/S producing ergometrin and ergotoxin yielded an alkaloid-blocked mutant Pepty 695/ch producing chanoclavine-I-aldehyde (100 #g/ml) and chanoclavine-I (400 #g/ml) [7,8].…”