Effect of certain nitrogenous heterocyclic compounds on carotenogenesis in Verticillium agaricinum.

Pyridine, isonicotinoylhydrazide and 1-methylamidazole have been used to investigate carotenoid biosynthesis in V. agaricinum. The results suggest that both torulin (C40) and neurosporaxanthin (C35) are formed from the precursors phytoene and phytofluene. These was no evidence of lycopene accumulation under these conditions. After 4 days' growth in the presence of isocotinolyhydrazine the fungus contained torulin and neurosporaxanthin only, whereas after 7 days, seven other carotenoids appeared as well, some of which were at the early stages of carotenoid biosynthesis. There results cannot be explained on the basis of a system consisting of free enzymes but of an enzyme aggregate already proposed for Phycomyces.