Modification of the radiation resistance of Aspergillus flavus mycelial units by some chemicals.

Survival curves for the mycleium of Aspergillus flavus Link var. columnaris Raper and Fennell were constructed after irradiation with gamma rays in the presence of NaCl, NaBr, NaI, KCl, KBr, KI, CaCl2, CaBr2, CaI2, Ca(NO3)2, NaNO2, NaNO3, KNO2, iodoacetic acid, iodoacetamide and vitamin K5. In addition iodized salt was also tested. All the chemicals tested exhibited initial toxicity at zero dose. However, most of the chemicals demonstrated a synergism when present during irradiation. Compounds containing iodine were invariably the strongest radiosensitizers. The iodine present as an admixture in salt also retained its radiosensitizing character. Sodium bromide and calcium bromide behaved in a different way. The initial toxicity was reduced along with an increase in radiation dose resulting in more survival.