Ephrati-Elizur E, Borenstein S
J Bacteriol. 1971 Apr;106(1):58-64. doi: 10.1128/jb.106.1.58-64.1971.
Chromosomes in spores of a thymineless mutant of Bacillus subtilis strain 168 were shown to have a replication fork, unlike chromosomes in spores of the thy(+) strain which are in a complete form. As a consequence the number of replication forks in germinating cultures is higher in the thy(-) strain than in the thy(+) one. Chromosome replication time (C) in the thy(+) strain was found to be about 53 min for growth rates from 20 to 60 min. In the thy(-) strain, C was about 75 min at high growth rates and increased with decreasing growth rate when the thymine concentration was not limiting. With limiting thymine concentrations in the medium replication velocity decreased independently of growth rate.
已表明，枯草芽孢杆菌168胸腺嘧啶缺陷型突变体孢子中的染色体具有复制叉，这与胸腺嘧啶正常（thy(+)）菌株孢子中呈完整形态的染色体不同。因此，在萌发培养物中，胸腺嘧啶缺陷型（thy(-)）菌株的复制叉数量高于胸腺嘧啶正常（thy(+)）菌株。发现胸腺嘧啶正常（thy(+)）菌株中，生长速率在20至60分钟时，染色体复制时间（C）约为53分钟。在胸腺嘧啶缺陷型（thy(-)）菌株中，高生长速率时C约为75分钟，当胸腺嘧啶浓度无限制时，C随生长速率降低而增加。当培养基中胸腺嘧啶浓度有限时，复制速度会独立于生长速率而降低。
