抗坏血酸对λ噬菌体紫外诱导过程的影响

Effects of Ascorbic Acid on the UV Induction of Bacteriophage λ

本文通过研究抗坏血酸对紫外诱导λ噬菌体的影响 ,从自由基角度探讨了λ噬菌体紫外诱导过程的机制。结果表明抗坏血酸可有效抑制紫外对λ噬菌体的诱导 ,抑制效果具有明显的量效性。抗坏血酸浓度为 31 .8μmol/L时 ,抑制率高达 98%。细胞密度影响试验表明细胞密度为 4× 1 0 8cells/m L时 ,噬菌斑形成单位数最高。随着细胞密度的逐渐增加或减少 ,噬菌斑形成单位数均呈下降趋势。利用电子自旋共振及自旋捕捉技术 ,检测到紫外诱导过程中的自由基信号 ,其强弱与细胞密度密切相关 ,1 0 8cells/m L时自由基的信号明显强于 1 0 10 cells/m L。抗坏血酸的加入可消除所产生的自由基信号。由此可得出结论 :λ噬菌体的诱导裂解与自由基密切相关 。

According to the studies of the effects of ascorbic acid on the UV induction of bacteriophage λ, this paper explored the mechanism of the UV induction of bacteriophage λ from the angle of free radicals. The results showed that ascorbic acid could efficiently inhibit the UV induction of bacteriophage λ and the inhibitory rate was close related to the concentration of ascorbic acid. At 31.8 μmol/L, the inhibitory rate reached to 98%. Experiments of the cell density showed that the plaque forming unit was the highest at 4×10 8 cells/mL, and with the increase or the decrease of the cell density, both of the plaque forming unit decreased gradually. By electron spin resonance and spin trapping technique, free radicals were detected in the solution of lysogenic bacteria by UV irradiation. The signal of 10 8 cells/mL was clearly stronger than that of 10 10 cells/mL. The addition of ascorbic acid eliminated the signals produced. Therefore, conclusion can be made that there is close relation between the UV induction of bacteriophage λ and the free radicals produced in the process, and ascorbic acid inhibit the UV induction of bacteriophage λ by scavenging the free radicals.