X-Irradiation of Escherichia coli
An investigation was made on the effects of changes in temperature and growth rate on the post-irradiation viabil ity in E. coli. Two x-ray doses (4 and 8 kr) were given, the irradiated cells were incubated at 37 or 15 deg C, and colony counts were made after or 5 to 6 days, respectively. The temperaure did not significantly affect the number of non-irradiated cortrols, and only a small difference was found in the case of irradiated cells. The appearance of the colonies, however, differed greatly, and it was discovered that E. coli comprises two types of cells, filamentous forms forming petite colonies and single cells formr-ng large colonies. The filamentous forms were found to be more radiosensitive than single cells and to have a smaller O2 enchancement ratio. Cultures were grown from single colonies of both types to see whether the characteristics of the cells were maintained on growth at different temperatures; a clear separation of the cell types resulted. It is concluded that the formation of filaments in E. coli under unfavorable conditions complicates interpretation of irradiation effects.
- Research Organization:
- Cambridge Univ., Eng.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-16-028799
- OSTI ID:
- 4808053
- Journal Information:
- Nature (London), Journal Name: Nature (London) Journal Issue: 4844 Vol. 195; ISSN 0028-0836
- Publisher:
- Nature Publishing Group
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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