923. Studies in relation to biosynthesis. Part XVII. Sclerotiorin, citrinin, and citromycetin

Abstract

The routes of biosynthesis, in appropriate moulds, of the substances named in the title have been examined by means of feeding experiments with 14C-labeUed acetic and formic acids. SOME previous papers dealt with a speculative examination of the biosynthetic origins of plant and mould products from acetic acid by head-to-tail linkage, or from acetic acid and methionine. These predictions have been confirmed by direct experiment with CH3*14C02H in two cases 2*3 where the molecule can arise from a straight chain of acetic acid units joined by head-to-tail linkage, and in one case (mycophenolic acid) 4 5 where methionine is also involved. We have now extended our researches to trace the origins of molecules which can only arise from branched carbon chains. From previous work there seem to be three Iikely modes of origin : (A) From acetic acid, by head-to-tail linkage in a straight chain with the introduction of C, units from the C, pool (choline, methionine etc.). (B) From acetic acid by production of branched chains employing head-to-tail linkage. (C) By the isoprene route formally similar to (B) but with a definite intermediate in the form of mevalonic acid.Mycophenolic acid *J is an interesting example of the working of routes (A) and (C) in one compound; no example of route (B) had, before the present work, been demonstrated.

Semi-Quantitative Method with Fluorescence Detection of Citrinin in Fungal Cultures Isolated from Cheese and Cheese Factories

“…Similarly on day 4 when a jet of 200 mL of the medium was poured into a tube of 10 M HCl, it became yellow. This result is in agreement with earlier studies (Vail and Homman, 1980) in which citrinin production was detected as early as 20 h following inoculation and increased dramatically when the culture entered the stationary phase of growth, indicating that citrinin biosynthesis is associated with secondary metabolism (Birch et al, 1958;Schwenk et al, 1958).…”

Biosynthesis of Ochratoxin A1

“…This oxidation of a methyl group would then be similar to the situation reported by Gatenbeck (12) for the biosynthesis of 3-hydroxy-phthalic acid. If this is true, the carboxyl group attached to carbon 4 probably arose from the one-carbon pool of the organism, as demonstrated by Birch et al for a corresponding carboxyl group in citrinin from A. candidus (2).…”

History, Applications, Activity and Changes of Citrinin

“…Os primeiros trabalhos sugerem que a citrinina produzida pela espécie Aspergillus candidus é derivada de pentacetídeos formados pela condensação de cinco grupos de acetato e de três átomos de carbono. [28][29][30][31][32][33] Mais recentemente a rota biossintética foi confirmada utilizando marcadores isotópicos, sugerindo que a formação da citrinina seja através de tetracetídeos em culturas de Monascus ruber (Figura 4). A síntese da citrinina foi proposta em 1949 (Figura 5).…”