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THE a$alpha$ EFFECT, A CORRELATION BETWEEN THE MATING TYPE CONSTITUTION AND RADIATION RESISTANCE OF YEAST

Journal Article · · Zentr. Bakteriol. Parasitenk., Abt. I. Orig.
OSTI ID:4745318
The sensitivity to x rays and Po alpha rays of diploid strains of Saccharomyces, with mating type alleles of identical genotype (isogenic), was investigated in relation to the combinations of the alleles aa, alpha alpha , and a alpha . The results showed that the a alpha strain was more radioresistant than the 2 homozygous strains aa and alpha alpha , which showed similar radioresistance. The relative resistance of a alpha cells, referred to as the a alpha effect, is superimposed on other genetically conditioned resistance differences. For example, the radioresistant strain was more dependent upon the presence of serine and valine-isoleucine for growth than the homozygous, less resistant strains. In contrast to the observed sensitivity to x rays and alpha particles, the uv sensitivity of heterozygous and homozygous diploid strains of the yeast was the same. Since the a alpha strain was previously shown to have 1.2 to 1.5 times as much catalase activity as aa or a alpha strains, it is suggested that the radioresistance of this strain may be due to its enhanced ability to deal with the H/sub 2/O/sub 2/ or other peroxides which are formed in the primary radiation reaction. In this way, secondary reactions of peroxides with yeast cell constituents would be less apt to occur in the a alpha strain. Triploid strains of Saccharomyces showed the same sensitivity to ionizing and uv radiation, and the sensitivity could not be correlated with mating type alleles. (H.H.D.)
Research Organization:
Freie Universitat, Berlin
NSA Number:
NSA-17-017907
OSTI ID:
4745318
Journal Information:
Zentr. Bakteriol. Parasitenk., Abt. I. Orig., Journal Name: Zentr. Bakteriol. Parasitenk., Abt. I. Orig. Vol. Vol: 184
Country of Publication:
Country unknown/Code not available
Language:
English