Morris D R, Jorstad C M
J Bacteriol. 1973 Jan;113(1):271-7. doi: 10.1128/jb.113.1.271-277.1973.
A mutant of Escherichia coli with reduced levels of biosynthetic arginine decarboxylase was isolated which required putrescine or spermidine for optimal growth. The stimulation of growth by putrescine was 1.5- to 3-fold depending upon the culture medium. Specificity studies supported the concept that the requirement was for spermidine or closely related polyamines, or for diamines which could be converted enzymatically to these compounds. The behavior of the macromolecular composition of the polyamine-starved cells appeared abnormal. The ribonucleic acid to protein and deoxyribonucleic acid to cell ratios in the starved cells were both higher than expected on the basis of their growth rate. The stable ribonucleic acid in the polyamine-limited cells appeared to be normal as judged from size distribution and degree of methylation. The relationship of these results to mechanisms for regulation of nucleic acid and protein synthesis in E. coli is discussed.
分离出一种生物合成精氨酸脱羧酶水平降低的大肠杆菌突变体,该突变体需要腐胺或亚精胺才能实现最佳生长。根据培养基的不同,腐胺对生长的刺激作用为1.5至3倍。特异性研究支持了这样一种观点,即所需的是亚精胺或密切相关的多胺,或者是可以通过酶促转化为这些化合物的二胺。多胺饥饿细胞的大分子组成表现异常。饥饿细胞中的核糖核酸与蛋白质之比以及脱氧核糖核酸与细胞之比均高于根据其生长速率预期的值。从大小分布和甲基化程度判断,多胺受限细胞中的稳定核糖核酸似乎正常。本文讨论了这些结果与大肠杆菌核酸和蛋白质合成调控机制的关系。