Polyamines and RNA synthesis in a polyauxotrophic strain of E. coli.

Abstract

Polyamine patterns in E. coli were studied in their relation to RNA synthesis during either normal growth, amino acid deprivation, or treatment with chloramphenicol and streptomycin. Putrescine, spermldine, and their monoacetyl derivatives are the main polyamines in E. coli strain 15 TAU. Deprivation of arginine causes accumulation of putrescine within the cells, whereas the spermidine and RNA content remain essentially unchanged. Addition of chloramphenicol markedly increases the biosynthesis and accumulation of spermidine within the cells and also Increases the RNA content. However, treatment with streptomycin results in a moderate increase in intracellular spermidine, but causes a dramatic leakage of putrescine into the medium; the latter effect is delayed in the absence of arginine. Addition of spermidine to a medium devoid of arginine caused up to a sevenfold increase in uracll incorporation into RNA, and was slowly lethal. The stimulation of RNA synthesis, as well as lethality, was gradually abolished by Increasing amounts of putrescine.