[Exchange of polyamines between the cell and the environment as one of the factors determining the growth of cultures of Escherichia coli with additional feeding].

Escherichia coli growth in a synthetic medium with glucose is accompanied by the interdependent change of putrescine content in the cell and its environment, which maintains a homeostatic equilibrium. The rate of putrescine efflux at the early stage of the culture growth is directly proportional to putrescine intracellular pool but the rate of putrescine uptake is inversely proportional to its value. The constitutive form of ornithine decarboxylase with the pH optimum 8.0 is responsible for putrescine synthesis. Glucose deficiency favours the utilisation of acidic glucose metabolites but the homeostatic system of putrescine makes its intracellular content remain at a high level, which stimulates constructive processes in the following growth.