Pollard E C
Biophys J. 1978 Jun;22(3):431-8. doi: 10.1016/S0006-3495(78)85497-6.
Cells of E. coli that are recA+ and lex+ show a phenomenon of induced radioresistance. A preexposure to ultraviolet light, or ionizing radiation followed by incubation to allow protein synthesis, followed by treatment with rifampin to prevent further induction, renders the cells resistant to further doses of radiation. When this is attempted with lambda lysogens of the same strains, no radioresistance is seen, even though the preexposure is too small to induce lambda itself. If the lysogens are ind-, namely lambda C1857, about the normal radioresistance can be developed by pretreatment. These findings suggest that the lambda repressors can bind to single-strand breaks caused by the inducing agent and can modify the course of induction.
recA+和lex+的大肠杆菌细胞表现出诱导抗辐射现象。预先暴露于紫外线或电离辐射，随后进行孵育以允许蛋白质合成，接着用利福平处理以防止进一步诱导，可使细胞对进一步的辐射剂量产生抗性。当对相同菌株的λ溶原菌进行此操作时，即使预先暴露量太小不足以诱导λ本身，也看不到抗辐射现象。如果溶原菌是ind-，即λC1857，通过预处理可产生大约正常的抗辐射能力。这些发现表明，λ阻遏物可与诱导剂引起的单链断裂结合，并可改变诱导过程。
