Genotoxicity of selenite in diploid yeast.

Selenite, a chemical of industrial importance and also an antimutagenic/anticarcinogenic agent, was tested for mutagenic and recombinogenic effects in 2 diploid yeast strains, Saccharomyces cerevisiae BZ 34 and D7. Selenite induced gene conversion and toxicity in BZ 34 and a variety of genetic events, viz. back-mutation, gene conversion, mitotic crossing-over, aberrant colony formation and also toxicity in the D7 strain.

Combined mutagenic action of chemicals and radiation in diploid yeast.

The interaction between the mutagenic action of chemicals and radiation was studied by using a diploid yeast strain Saccharomyces cerevisiae BZ 34 with mitotic gene conversion as the end-point. The cells were treated with EMS, MMS or 4-NQO alone or in combination with gamma-radiation. The 2 alkylating agents EMS and MMS produced an additive mutagenic response, whereas 4-NQO exhibited an antagonistic effect in the combined treatment with gamma-radiation.

Use of the FBX dosemeter for the calibration of cobalt-60 and high-energy teletherapy machines.

The doses from the cobalt-60 teletherapy machines were measured using the FBX and secondary-standard dosemeters of Farmer-Baldwin type. The FBX dosemeter contained 0.20 mM ferrous ammonium sulphate, 5.

Comparison of sensitivity of rad mutants of diploid yeast to heat and gamma radiation: cellular target for heat inactivation.

Wild type and radiation-sensitive mutants rad 53, 54 and 55 of the diploid yeast Saccharomyces cerevisiae, in stationary and log phase were exposed to gamma radiation and hyperthermia (51 degrees C) in order to compare their sensitivity to these agents. The wild type diploid strain exposed to gamma rays showed a sigmoidal survival curve both in stationary and log phase cultures. Log phase cells were significantly more resistant than stationary phase cells.