Michelsen Ole, Teixeira de Mattos M Joost, Jensen Peter Ruhdal, Hansen Flemming G
Section of Molecular Microbiology, BioCentrum - DTU, Technical University of Denmark - DTU, Building 301, DK-2800 Lyngby, Denmark.
Department of Microbiology, E. C. Slater Institute, BioCentrum Amsterdam, University of Amsterdam, 1018 WS Amsterdam, The Netherlands.
Microbiology (Reading). 2003 Apr;149(Pt 4):1001-1010. doi: 10.1099/mic.0.26058-0.
The C and D cell cycle periods of seven Escherichia coli K-12 strains and three E. coli B/r strains were determined by computer simulation of DNA histograms obtained by flow cytometry of batch cultures grown at several different generation times. To obtain longer generation times two of the K-12 strains were cultivated at several different dilution rates in glucose-limited chemostats. The replication period (C period) was found to be similar in K-12 and B/r strains grown at similar generation times. At generation times below 60 min the C period was constant; above 60 min it increased linearly with increasing generation time. The period from termination of replication to cell division (D period) was more variable. It was much shorter in B/r than in K-12 strains. Like the C period it was relatively constant at generation times below 60 min and it increased with increasing generation times at longer generation times. In glucose-limited chemostats good correlation was found between D periods and generation times, whereas batch cultures exhibited carbon-source-dependent variations. Chemostat cultures showed cell cycle variations very similar to those obtained in batch cultures. These flow cytometric determinations of cell cycle periods confirm earlier determinations of the C period and establish that the D period also varies with generation time in slowly growing cultures. In addition they extend the range of growth rates at which cell cycle periods have been determined in E. coli K-12.
通过对在几个不同代时生长的分批培养物进行流式细胞术获得的DNA直方图进行计算机模拟，确定了7株大肠杆菌K - 12菌株和3株大肠杆菌B/r菌株的C期和D期细胞周期。为了获得更长的代时，将其中两株K - 12菌株在葡萄糖限制的恒化器中以几种不同的稀释率进行培养。发现在相似代时生长的K - 12和B/r菌株中，复制期（C期）相似。在代时低于60分钟时，C期是恒定的；高于60分钟时，它随代时增加而线性增加。从复制终止到细胞分裂的时期（D期）变化更大。它在B/r菌株中比在K - 12菌株中短得多。与C期一样，在代时低于60分钟时它相对恒定，在更长代时时随代时增加而增加。在葡萄糖限制的恒化器中，发现D期与代时之间有良好的相关性，而分批培养物表现出碳源依赖性变化。恒化器培养物显示出与分批培养物中获得的细胞周期变化非常相似。这些细胞周期时期的流式细胞术测定证实了早期对C期的测定，并确定在缓慢生长的培养物中D期也随代时变化。此外，它们扩展了在大肠杆菌K - 12中已确定细胞周期时期的生长速率范围。
