THE CYTOLOGY AND GENETICS OF RADIATION RESISTANCE IN BACTERIA. Progress Report for the Period of February 1, 1955 to November 1, 1955
Technical Report
·
OSTI ID:4161419
Cytological observations on Nocardia corallina indicated a haploid mycelial phase and a diploid coccoidal phase of growth. Dose-survivor curves of the coccoids were sigmoidal in shape, which can be interpreted as being indicative of a diploid organism. Because of this evidence of diploidy, the organism was used as a test organism to investigate the unpaired defect theory of Tobias. It was found that successive irradiation of the culture resulted first in increased sensitivity and an exponential dose-survivor response as unpaired defects accumulated. Further successive irradiation caused increased resistance and experiments indicated that this was due to selection for a normally resistant cell present in the parent culture. Preliminary cytological investigations were carried out on each culture, and the only observable change was that the cells became smaller as resistance increased. A comparison of x-ray and ultraviolet light effects indicated that the first effect of both is the same in the cell although the mechanisms apparently differ. In the case of ultraviolet light, evidence is being accumulated which shows both a direct and an indirect effect on direct irradiation. It was found that the haploid phase of Micrococcus aureus maintained a constant dose-survivor response on successive irradiation. This is additional validation of the unpaired defect theory. Preliminary radiobiological investigations were carried out on the "het" strain of Escherichia coli K-12 and a copper resistant Escherichia coli B. Results of these experiments were inconclusive. (auth)
- Research Organization:
- Oklahoma. Univ., Norman. Research Inst.
- NSA Number:
- NSA-14-017692
- OSTI ID:
- 4161419
- Report Number(s):
- ORO-282
- Country of Publication:
- United States
- Language:
- English
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Technical Report
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Sun Oct 30 23:00:00 EST 1960
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OSTI ID:4150382
THE CYTOLOGY AND GENETICS OF RADIATION RESISTANCE IN BACTERIA. Progress Report for the Period of November 1, 1955 to November 1, 1956
Technical Report
·
Sun Oct 30 23:00:00 EST 1960
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OSTI ID:4150417
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Journal Article
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Tue Mar 31 23:00:00 EST 1959
· Journal of Bacteriology (U.S.)
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OSTI ID:4259787