Joers, A. | bioRxiv Science

bioRxiv2019

Dividing subpopulation of Escherichia coli in stationary phase

The bacterial growth cycle contains different phases: after the growth substrate is exhausted of the toxic waste products accumulate the growth stops. In this non-growing culture the number of colony forming bacteria remains constant or starts to decrease. It has been shown that during prolonged incubation there is constant growth and death of bacteria and certain mutant populations take over the culture. Here we show that the dynamic cell division and death balance can be obtained even before mutants take over the culture.

microbiology↗

bioRxiv2019

Muropeptides Stimulate Growth Resumption from Stationary Phase in Escherichia coli

When nutrients run out, bacteria enter a dormant metabolic state. This low or undetectable metabolic activity helps bacteria to preserve their scant reserves for future, but also diminishes their ability to trace the environment for new growth-promoting substrates. However, neighboring microbial growth is a sure indicator of favorable environment and thus, can serve as a cue for exiting the dormancy. Here we report that for Escherichia coli this cue is the basic peptidoglycan unit (i.e. muropeptide). We show that several forms of muropeptides can stimulate growth resumption of dormant E. coli cells, but the sugar - peptide bond is crucial for activity. We also demonstrate that muropeptides from several different species can induce growth resumption of E. coli and also Pseudomonas aeruginosa. These results, together with the previous identification of muropeptides as germination signal for bacterial spores, makes muropeptides rather universal cue for bacterial growth.

microbiology↗