Medoff G, Overholt S
J Bacteriol. 1970 Apr;102(1):213-6. doi: 10.1128/jb.102.1.213-216.1970.
Thymineless death was examined in Escherichia coli 15T(-) and recombinants of 15T(-) and E. coli K-12. Those strains that were very sensitive to thymine deprivation were also very sensitive to a variety of inducing agents (mitomycin C, ultraviolet light, hydroxyurea, and nalidixic acid). Those strains that were relatively resistant to thymineless death were also relatively resistant to the inducing agents. After exposure to thymineless death and the inducing agents, sensitive strains lysed, produced colicin, and had phage particles in their lysates. These strains also showed an increase in the 6-methyladenine content of their deoxyribonucleic acid (DNA) and an increase in the DNA methylase activity of their crude extracts under these conditions. None of these effects was noted in the strains relatively resistant to thymineless death and the inducing agents. These data indicate that there are two types of thymineless death. One is represented by the strains that are very sensitive to thymine deprivation and other inducing agents and is secondary to the induction of phage psi. The strains more resistant to thymine deprivation and the other inducing agents undergo a non-phage-mediated thymineless death. The mechanism of this latter process is currently under study.
在大肠杆菌15T(-)以及15T(-)与大肠杆菌K-12的重组体中研究了无胸腺死亡现象。那些对胸腺嘧啶缺乏非常敏感的菌株，对多种诱导剂（丝裂霉素C、紫外线、羟基脲和萘啶酸）也非常敏感。那些对无胸腺死亡相对有抗性的菌株，对诱导剂也相对有抗性。在经历无胸腺死亡和诱导剂处理后，敏感菌株会裂解、产生大肠杆菌素，并且在其裂解物中有噬菌体颗粒。在这些条件下，这些菌株的脱氧核糖核酸（DNA）中6-甲基腺嘌呤含量增加，其粗提物中的DNA甲基化酶活性也增加。在对无胸腺死亡和诱导剂相对有抗性的菌株中未观察到这些效应。这些数据表明存在两种类型的无胸腺死亡。一种由对胸腺嘧啶缺乏和其他诱导剂非常敏感的菌株所代表，并且是噬菌体ψ诱导的结果。对胸腺嘧啶缺乏和其他诱导剂更有抗性的菌株经历的是一种非噬菌体介导的无胸腺死亡。后一过程的机制目前正在研究中。
