Outer Membrane Vesicle Secretion: From Envelope Stress to Biofilm Formation

Résumé fourni par la source

Modifications of the cell envelope comprise one important mechanism of bacteria for dealing with environmental stress and coping with toxic hydrocarbons. In the present study, we investigate the impact of n-alkanols and chlorophenols on the cell surface properties of the solvent-tolerant bacterium Pseudomonas putida DOT-T1E. Depending on the chain length of toxic concentrations of n-alkanols, this strain increases its cell surface hydrophobicity dramatically. This response is shown to be fast and does not appear in cells killed before the addition of the solvent. Also, the increase of the cell surface hydrophobicity is reversible, demonstrating that the change in the physicochemical surface properties of P. putida DOT-T1E is a real physiological response. Furthermore, the increase in the cell surface hydrophobicity could be correlated to the loss of a specific fraction of lipopolysaccharides. A similar response was observed after treating P. putida DOT-T1E with NaCl, with EDTA, and after heat shock. We observed that these changes in the surface hydrophobicity are correlated to the secretion of outer membrane vesicles (OMVs). Strikingly, the release of OMVs leads to a higher tendency to form biofilms. In summary, we conclude that cell surface stress in P. putida leads to an increased cell surface hydrophobicity by the secretion of OMV, resulting in elevated biofilm formation.

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