Regulation of aflatoxin biosynthesis. 1 Comparative study of mycelial composition and glycolysis in aflatoxigen and nonaflatoxigenic strains.

A comparative biochemical study of an aflatoxigenic strain Aspergillus parasiticus NRRL 3240 and a nonaflatoxigenic strain A. flavus NRRL 3237 was carried out in order to have a better idea of regulation of aflatoxin biosynthesis. The results obtained revealed continuous primary metabolic activity (protein synthesis) in the nonaflatoxigenic strain while the aflatoxigenic stain showed inhibition of protein and nucleic acid synthesis. The aflatoxigenic strain showed higher levels of oxygen uptake, RNA, NAD, FMN and activities of glycolytic enzymes. Furthermore, it had lower of lipids and reduced activity of glucose-6-phosphate dehydrogenase, which is a source for NADPH. The differences observed have been discussed in relation to aflatoxin biosynthesis and its regulation.