Low doses of gamma-radiation induce SOS response and increase mutation frequency in Escherichia coli and Salmonella typhimurium cells

• Low doses of γ-radiation induced SOS response of Escherichia coli.
• Low doses of radiation adversely affected the survival of S. typhimurium cells.
• Gamma-radiation increased mutation frequency in S. typhimurium cells.
• The highest radiation-induced responses were observed in the first 24 h of exposure.

This study addresses use of two bacterial test systems (the Ames test and the SOS chromotest) to estimate the effects of low doses of γ-radiation. The most substantial increases in induction of SOS response and mutation frequencies were observed in the first 24 h of exposure to γ-radiation as compared to the cells in the exposure-free control. Gamma-radiation also impaired growth and survival of S. typhimurium cells in the first 24 h. The effects were attenuated at lower exposure doses and at longer exposure times. In the experiments conducted in this study, at 96 h of exposure, the values of some of the γ-radiation effects were lower than the MID (minimum inducing dose) detection limits and, thus, were neglected. Long-term exposure to γ-radiation could also result in combined effects of γ-radiation and the death of cells in the culture.