Sadowski P D, Kerr C
J Virol. 1970 Aug;6(2):149-55. doi: 10.1128/JVI.6.2.149-155.1970.
The degradation of bacterial deoxyribonucleic acid (DNA) was studied after infection of Escherichia coli B with DNA-negative amber mutants of bacteriophage T7. Degradation occurred in three stages. (i) Release of the DNA from a rapidly sedimenting cellular structure occurred between 5 and 6 min after infection. (ii) The DNA was cleaved endonucleolytically to fragments having a molecular weight of about 2 x 10(6) between 6 and 10 min after infection. (iii) These fragments of DNA were reduced to acid-soluble products between 7.5 and 15 min after infection. Stage 1 did not occur in the absence of the gene 1 product (ribonucleic acid polymerase sigma factor), stage 2 did not occur in the absence of the gene 3 product (phage T7-induced endonuclease), and stage 3 did not occur in the absence of the gene 6 product.
在用噬菌体T7的DNA阴性琥珀突变体感染大肠杆菌B后，研究了细菌脱氧核糖核酸（DNA）的降解情况。降解过程分三个阶段进行。（i）感染后5至6分钟内，DNA从快速沉降的细胞结构中释放出来。（ii）感染后6至10分钟内，DNA被内切核酸酶切割成分子量约为2×10⁶的片段。（iii）感染后7.5至15分钟内，这些DNA片段被降解为酸溶性产物。第一阶段在缺乏基因1产物（核糖核酸聚合酶σ因子）时不会发生，第二阶段在缺乏基因3产物（噬菌体T7诱导的内切核酸酶）时不会发生，第三阶段在缺乏基因6产物时不会发生。
