Metabolic exchange and energetic coupling between nutritionally stressed bacterial species, the possible role of QS molecules

To clarify the principles controlling inter-species interactions, we previously developed a co-culture model with two anaerobic bacteria, and Hildenborough, in which nutritional stress for induced tight cell-cell inter-species interaction. Here we show that exchange of metabolites produced by allows to duplicate its DNA, and to be energetically viable even without its substrates. Physical interaction between and (or and ) is linked to the quorum-sensing molecule AI-2, produced by . and . With nutrients produces a small molecule that inhibits the AI-2 activity, and could act as an antagonist . Sensing of AI-2 by could induce formation of an intercellular structure that allows directly or indirectly metabolic exchange and energetic coupling between the two bacteria.