engleski

Growth advantage in stationary phase phenomenon in the mixture of Escherichia coli and Salmonella enterica

Stressful environment, which is non favourable for growth, forces static microorganisms to rearrange their metabolism and increase the rate of random mutagenesis. The ability of stationary phase of E. coli to grow for a long period of time, over three years, during carbon starvation has been termed Growth Advantage in Stationary Phase (GASP) phenotype. This phenomenon has been observed in a range of microorganisms, including gram-negative and gram-positive bacteria. GASP phenotype confers with a loss of function of the rpoS gene, which encodes a stationary phase global regulator sigma S. The purpose of our study was to analyze mixed populations of E. coli K12 and S. enterica serovar Typhimurium during the prolonged period of carbon starvation due to the evaluation of the GASP phenomenon. In the mixed cultures during eleven days of growth in minimal medium, the aged cells or the rpoS mutant of E. coli do not have the ability to overgrow the younger or the cells of the same age of another bacterial species. We have isolated isogenic mutants resistant to streptomycin or nalidixic acid that show the presence of GASP phenomenon. We presume that the phenomenon might be caused by additional stress, such as resistance to a growth inhibitor.

Escherichia coli; Salmonella enterica

nije evidentirano