Polyamine, Magnesium and Ribonucleic Acid Levels in Steady-state Cultures of the Mould Aspergillus nidulans

Abstract

Results from experiments in vitro strongly suggest that major roles can be ascribed to polyamines in controlling the stability, activity and synthesis of ribonucleic acids. Furthermore, functional substitution of polyamines for inorganic cations, particularly magnesium ions, in cell-free protein synthesis is well substantiated (see Cohen, 1971). Recently we have been analysing the effects of culture conditions on the chemical composition of Aspergillus nidulans and have found fluctuations in polyamine and magnesium concentrations in response to a changing environment, while biomass and RNA remained constant. This paper describes the influence of steady-state growth rate on hyphal concentrations of spermidine, spermine and Mg²⁺ ions.