Dependency on Medium and Temperature of Cell Size and Chemical Composition during Balanced Growth of Salmonella typhimurium

TLDR

The study measured cell mass, nuclei per cell, and RNA/DNA content of *Salmonella typhimurium* during balanced growth in various media. The authors found that cell mass, nuclei per cell, and RNA/DNA content scale exponentially with growth rate, are independent of temperature, and that increased ribonucleoprotein at higher rates accounts for mass changes while protein synthesis per RNA remains constant, indicating many stable physiological states.

Abstract

Summary: Ceil mass, the average number of nuclei/cell and the content of RNA and DNA were studied in (Salmonella typhimurium during balanced (steady state) growth in different media. These quantities could be described as exponential functions of the growth rates afforded by the various media at a given temperature. The size and chemical composition characteristic of a given medium were not influenced by the temperature of cultivation. Thus, under conditions of balanced growth, this organism exists in one of a large number of possible stable physiological states. The variations in mass/cell are due to changes in the number of nuclei/cell as well as in mass/nucleus. An increase in the number of ribonucleoprotein particles at higher growth rates could, it appears, largely account for the increase in mass/nucleus. Calculations indicate that the rate of protein synthesis per unit RNA is nearly the same at all growth rates.