Relation of Ribonucleic Acid Composition to Growth Rate and Dormancy in Bacillus subtilis

Abstract

RECENTLY, Kjeldgaard and Kurland¹ have shown with Salmonella typhimurium that the ratio of soluble RNA to DNA is constant at all growth rates, and that the increase in cell RNA content with increasing growth rates results from an increase in the ratio of ribosomal RNA to DNA. Protein synthesis was also directly related to the amount of ribosomal RNA present. The results of these investigations indicate that the ratio of soluble RNA to ribosomal RNA increased at lower growth rates. If this relationship between the two major RNA fractions of bacterial cells is consistent, one might expect a relatively high soluble RNA to ribosomal RNA ratio in spores which are a non-growing stage in certain bacterial species. An analysis of vegetative cells and spores of Bacillus subtilis was undertaken therefore to determine if this relationship between RNA composition and growth rate was maintained.