The Production of Sporidesmin and Sporidesmolides by

Abstract

SUMMARYMethods for the assay of sporidesmin and the sporidesmolides were worked out and used in the study of the production of these metabolites by Pithomyces chartarum (Commonwealth Mycological Institute, Kew, England, Herbarium no. 74873) growing on an enriched potato carrot medium. High yields of sporidesmin and the sporidesmolides were associated with high utilization of medium constituents. No increase in the quantity of sporidesmin isolated from unit volume of medium was observed after the third day of incubation, despite further rapid growth of the fungus; by contrast good correlation was observed between the weight of sporidesmolides produced and fungal growth. These results were successfully applied to the production of experimental quantities of these materials.

Spore Surface Depsipeptides in Some Pithomyces Species

“…For isolation of depsipeptides, the organisms were grown on potato glucose agar slopes, and spores washed from these with sterile 0.05% (v/v) Lissapol N (Imperial Chemical Industries Ltd., Millbank, London) were used for inoculum. The medium for Pithomyces chartarum was potato + carrot extract (Done, Mortimer, Taylor & Russell, 1961), and that for IMI 101184 and P. maydicus IMI 46232 was the salts +glucose + asparagine medium of Ross (Butler, Russell & Clarke, 1962). For P. maydicus 1~198084 and for IMI 102682 this medium was enriched with yeast extract (0.1 yo, w/v; 'Difco' brand, Baird & Tatlock, Ltd., Chadwell Heath, Essex).…”

“…The bottles were incubated in a horizontal position for 2 weeks at 25", while being illuminated intermittently as above. At the end of the incubation the fungus was collected, washed and dried as previously described (Done et al 1961).…”

“…The crude depsipeptide was dissolved in chloroform (4 ml.) and the solution decolorized by passage through activated carbon as previously described (Done et al 1961). It was advantageous to support the carbon on a similarly sized pad of aluminium oxide (British Drug Houses Ltd., Poole, Dorset; 'for chromatography').…”

“…chartarum was affected by light, and thereafter we adopted standard conditions of illumination for all cultures. Dried felts of each of the other isolates were first analysed by the technique used for determining sporidesmolides in Pithomyces chartarum (Done et al 1961), but with the use of pure ether in place of sporidesmolide-saturated ether. In every case but that of P. sacchari, materials were isolated whose properties were similar to those of sporidesmolides: they were insoluble in water, very difficult to wet, very sparingly soluble in ether and readily soluble in chloroform.…”

“…Sporidesmolides were accordingly extracted from dried P. chartarurn felts by brief washing with chloroform, and were readily and quantitatively isolated from the extracts in pure form. When the chloroform-washed fungal tissue was dried and further extracted with hot methanol (Done et al 1961), no more sporidesmolides were obtained.…”