[Decreased synthetic activity as a possible cause of the death of Escherichia coli bacteria during amino acid starvation].

The work is concerned with studying the breakdown of proteins and RNA when a polyauxotrophic Escherichia coli strain is incubated in a salt solution without amino acids, phosphorus, nitrogen and glucose at 43 degrees C as well as the ability of starving bacterial cells to recommence protein and RNA synthesis (also in the course of phage T4 infection) and to reproduce bacteriophages T4, lambda and MS2. Within the first two hours of the incubation, 12% of proteins and 40% of RNA break down to acid-soluble fragments. Then protein degradation stops while RNA decomposition goes on, but at a lower rate. Within 4-6 h of starvation, the rate of protein and RNA synthesis drops down 4-5 times and the survival rate equals 40-60% when the cells are transferred onto a complete medium. The quantitative characteristics of phages T4, lambda and MS2 reproduction fall down in prestarved cells. The authors speculate that E. coli cells die off in the course of starvation not because some unique structure is destroyed, but owing to the fact that the activity of enzymes and ribosomes gradually declines. As a result, the synthetic activity of the cell drops down abruptly and irreversibly because the enzymes are inactivated and RNA breaks down, which eventually causes cell death.