Ricard M, Hirota Y
J Bacteriol. 1973 Oct;116(1):314-22. doi: 10.1128/jb.116.1.314-322.1973.
Thermosensitive fts mutants of Escherichia coli belonging to seven previously identified genetic classes (ftsA to ftsG) were studied from a physiological standpoint. These mutants immediately stopped dividing and formed multinucleated filaments when the temperature was shifted to 41 C. Macromolecular syntheses (deoxyribonucleic acid), ribonucleic acid, cell mass, and murein) continued exponentially for at least 40 to 120 min. The number of surviving bacteria remained constant during the time of incubation, and this number began to decrease exponentially, as the rate of cell mass increase leveled off from the initial rate. The recovery of cell division at 30 C in these filamentous cells was studied after 60 min of incubation at 41 C. The existence of three types of mutants was shown. The ftsA and ftsE mutants resumed cell division without new protein synthesis; ftsD mutants resumed cell division only if new protein synthesis occured, while ftsB, C, F and G mutants did not resume cell division at all. No alteration in the cell envelope was detected by the method used here, although the ftsA, B, D, F and G mutations, in contrast with ftsC and E, caused an increased resistance to penicillin G. It was also shown that the recA mutation did not suppress the effect of the fts mutations and that none of the lysogenic fts mutants induced prophage multiplication while forming filaments. The effects of osmotic pressure and salts which rescue the mutant phenotype is described.
从生理学角度研究了大肠杆菌的热敏fts突变体，这些突变体属于先前确定的七个遗传类别（ftsA至ftsG）。当温度升至41℃时，这些突变体立即停止分裂并形成多核丝状体。大分子合成（脱氧核糖核酸、核糖核酸、细胞质量和胞壁质）至少持续指数增长40至120分钟。在孵育期间存活细菌的数量保持恒定，随着细胞质量增加速率从初始速率趋于平稳，这个数量开始呈指数下降。在41℃孵育60分钟后，研究了这些丝状细胞在30℃时细胞分裂的恢复情况。结果显示存在三种类型的突变体。ftsA和ftsE突变体在没有新蛋白质合成的情况下恢复细胞分裂；ftsD突变体只有在发生新蛋白质合成时才恢复细胞分裂，而ftsB、C、F和G突变体根本不恢复细胞分裂。尽管ftsA、B、D、F和G突变与ftsC和E相反，会导致对青霉素G的抗性增加，但用此处使用的方法未检测到细胞包膜有改变。还表明recA突变不会抑制fts突变的作用，并且溶原性fts突变体在形成丝状体时均不会诱导前噬菌体增殖。描述了渗透压和盐对挽救突变体表型的影响。
