A COMPARATIVE ANALYSIS OF THE POST-RADIATIONAL RECUPERATION OF DIPLOID YEAST IRRADIATED WITH ALPHA AND GAMMA RAYS (in Russian)
BS>It had been found that in the irradiation of cells having a minimum of two sets of chromosomes (yeast cells) by gamma rays, the survival of these cells increases significantly after incubating in a non-nutrient medium. This recuperative effect can be represented by a process rate beta and a coefficient of irreversibility k according to the equation: D/sub t/ = D/sub O/STAk + (1 - k)e/sup - /sup bt/!, where D/sub t/ is th e effective dose after t hours and D/ sub o/ is the dose administered. The coefficient of irreversibility k indicates the fraction of absorbed radiation energy which causes irreversible changes in the cells. Yeast cells, Saccharomyces vini of the strain Megri-139 B, were irradiated at 1 to 2 deg C for 1 to 22 hours with alpha particles of Pu/sup 239/. Samples of the yeast cells were counted immediately after irradiation, and also 24 and 48 hours later. On plotting the log of the survival of the yeast cells versus the fraction of the dose at 50% survival, the values of k alpha and k gamma were found to be independent of dose, and were equal to 0.38 plus or minus 0.014 and 0.41 plus or minus 0.023 respectively. Thus, the irreversible damage undergone by the diploid yeast cells is practically the same for gamma irradiation and alpha irradiation. An acceptable model is one consisting of many targets which are struck individually by radiation. Since, with alpha radiation, thousands of ion pairs are formed within a path length of 1 mu , the cross- section of the target undergoing damage is of the order of tens of angstroms which are the dimensions of a number of proteins and nucleoproteins. (TTT)
- Research Organization:
- Inst. of Radiology and Physical-Chemical Biology, Academy of Sciences, USSR; Moscow State Univ.
- NSA Number:
- NSA-15-027421
- OSTI ID:
- 4839313
- Journal Information:
- Doklady Akad. Nauk S.S.S.R., Journal Name: Doklady Akad. Nauk S.S.S.R. Vol. Vol: 138
- Country of Publication:
- Country unknown/Code not available
- Language:
- Russian
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