Bonev M N, Kozubek S, Krasavin E A, Amirtajev K G
Joint Institute for Nuclear Research, Dubna, USSR.
Int J Radiat Biol. 1990 May;57(5):993-1005. doi: 10.1080/09553009014551111.
Lambda-prophage induction in repair-deficient and wild-type E. coli strains by heavy ions and gamma-rays has been investigated. The dose dependence of the fraction of induced cells has been measured and its initial slope (lambda-induction potency) determined. The induction by gamma-rays was found to be more efficient in a polA-repair-deficient strain; the value of lambda-induction potency is zero in lexA- and recA- strains. The lambda-induction potency increased with LET for wild-type cells but remained constant in the case of polA- mutant cells. It is suggested that the DNA damage triggering the lambda-prophage induction in the case of ionizing radiation could be a type of DNA single-strand break with complex structure which cannot be repaired by fast repair processes, and which requires a substantial level of energy deposition for induction in a DNA molecule.
研究了重离子和γ射线对修复缺陷型和野生型大肠杆菌菌株中λ噬菌体诱导的情况。测量了诱导细胞比例的剂量依赖性，并确定了其初始斜率（λ诱导潜能）。发现γ射线在polA修复缺陷型菌株中的诱导效率更高；在lexA和recA菌株中，λ诱导潜能的值为零。对于野生型细胞，λ诱导潜能随传能线密度（LET）增加，但对于polA突变型细胞则保持恒定。有人提出，在电离辐射情况下触发λ噬菌体诱导的DNA损伤可能是一种具有复杂结构的DNA单链断裂，这种断裂不能通过快速修复过程修复，并且在DNA分子中诱导需要相当水平的能量沉积。
