engleski

The Abortive Growth Advantage in Stationary Phase Phenomenon in Mixed Cultures of Bacteria Lactobacillus brevis and Salmonella enterica serovar Typhimurium

The ecosystems conditions, as metagenomic studies has shown, is result of microbial interactions and competition among microorganisms. Laboratory studies show that during prolonged starvation stress expressions, the Growth Advantage in Stationary Phase (GASP) phenomenon is manifested depending on the appearance of mutants in the population of non-sporogenic bacteria. The aim of present study was to analyse the competitive growth of the bacterial cultures Lactobacillus brevis 3.4. which was isolated from native Croatian fermented olives and Salmonella enterica serovar Typhimurium LT21 during the prolonged period of carbon starvation due to the evaluation of the GASP phenomenon. Growth dynamics of the mentioned bacterial batch cultures is studied in pure and mixed cultures at temperatures of 32 °C and 37 °C. During the prolonged stationary growth at 32 °C bacterial culture Salmonella enterica serovar Typhimurium LT21 did not show the growth advantage in stationary phase phenomenon in a mixed culture with Lactobacillus brevis 3.4., but at 37 °C abortive phenotype GASP was determined. In this research mass spectrometry was used to determine proteins present during the common growth of studied bacterial cultures and to determine the expression of advantageous genes. The proteome analysis of cells Lactobacillus brevis 3.4. and Salmonella enterica serovar Typhimurium LT21 grown in monocultures at 37 °C in a minimal medium identified proteins which function is cell protection during the stress and starvation, while in mixed cultures the analysis identified proteins which participate in carbohydrate metabolism and enzymes included in nucleotide and protein biosynthesis.

the growth advantage in stationary phase ; Lactobacillus brevis ; Salmonella enterica serovar Typhimurium

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