Effect of aflatoxin B1 on chromatin-bound ribonucleic acid polymerase and nucleic acid and protein synthesis in germinating maize seeds.

The treatment of germinating maize seeds (cv. Ganga 2) with aflatoxin B1 resulted in suppression of ribonucleic acid (RNA), protein, and deoxyribonucleic acid (DNA) synthesis at 3, 4, and 5 h, respectively. At or below the concentrations inhibitory for these in vivo syntheses, the toxin inhibited chromatin-bound DNA-dependent RNA polymerase activity. The synthesis of both polyadenylated and non-polyadenylated RNA was inhibited, but the effect on the former was more pronounced. Equilibrium dialysis and difference spectral and viscometric analyses showed a binding of aflatoxin B1 to DNA isolated from the seeds. It is proposed that the inhibition of RNA synthesis in maize seeds by the toxin is due to the interference with the RNA polymerase activity, which seems, at least partially, due to the impairment of DNA template functions.