Rapid and marked inhibition of rat-liver RNA polymerase by aflatoxin B-1.

From 15 minutes to 2 hours after the administration of aflatoxin B(1) invivo there is a 35-to 70-percent inhibition of DNA-directed RNA synthesis. The inhibition was reversed 12 and 24 hours later.

Aflatoxin B1: binding to DNA in vitro and alteration of RNA metabolism in vivo.

Aflatoxin B(1) binds to both native and denatured DNA, as shown by spectroscopy and equilibrium dialysis. It also strongly inhibits incorporation of cytidine into rat liver nuclear RNA and lowers the RNA content of the nucleus. The extremle toxicity and carcinogenicity of aflatoxin B(1) may be direct results of the affinity of this agent for DNA.

Effect of Aflatoxin B(1) on Cell Cultures.

Gabliks, J. (Massachusetts Institute of Technology, Cambridge), W. Schaeffer, L.

AFLATOXIN B2: CHEMICAL IDENTITY AND BIOLOGICAL ACTIVITY.

Aflatoxin B(2), a blue-fluorescent metabolite of Aspergillus flavus, was isolated from cultures grown on crushed wheat. Chemical structure of the compound was elucidated as dihydroaflatoxin B(1). Biological activity was determined in day-old male white Pekin ducklings.