Liebart J C, Buu A, Marcovich H
Proc Natl Acad Sci U S A. 1974 Jun;71(6):2445-8. doi: 10.1073/pnas.71.6.2445.
The replication of the chromosome of E. coli 15T(-) (thymine-requiring) has been followed for approximately four generations after a premature initiation of DNA synthesis by thymine starvation. Various labelings of the DNA with (14)C, (3)H, and density media allowed discrimination of the strands preexistent to thymine starvation from those which were made during the subsequent generations. Results were: (1) There is very little, if any, DNA degradation following 45 min of thymine starvation. (2) The growing points which existed prior to thymine starvation proceeded to the end of the chromosomes after resumption of DNA synthesis and then disappeared. (3) The premature DNA synthesis initiated by thymine starvation involved, symmetrically, all free origins; the entire chromosomal population was subjected to this process. (4) All the DNA which was synthesized during the progression of the premature growing points was normally replicated, i.e., with no delay or loss, during the next three generations.
在通过胸腺嘧啶饥饿提前启动DNA合成后，对大肠杆菌15T（-）（需要胸腺嘧啶）染色体的复制进行了大约四代的跟踪。用（14）C、（3）H和密度介质对DNA进行的各种标记，使得能够区分胸腺嘧啶饥饿之前就已存在的链与后续几代中合成的链。结果如下：（1）胸腺嘧啶饥饿45分钟后，即使有DNA降解，量也非常少。（2）胸腺嘧啶饥饿之前存在的生长点在恢复DNA合成后延伸至染色体末端，然后消失。（3）由胸腺嘧啶饥饿引发的过早DNA合成对称地涉及所有游离起始点；整个染色体群体都经历了这个过程。（4）在过早生长点进展过程中合成的所有DNA在接下来的三代中都正常复制，即没有延迟或损失。
