Impact of the biofilm mode of growth on the inner membrane phospholipid composition and lipid domains in Pseudomonas aeruginosa

• Published in: Biochimica et biophysica acta 2011-01, Vol.1808 (1), p.98-105
• Main Authors: Benamara, Hayette, Rihouey, Christophe, Jouenne, Thierry, Alexandre, Stéphane
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Bacterial Proteins - metabolism; Bacteriology; Biofilm; Biofilms; Cell Membrane - metabolism; Chemical Sciences; Fatty Acids - chemistry; Inner membrane; Life Sciences; Lipidome; Lipids - chemistry; Mass Spectrometry - methods; Mass spectroscopy; Membrane Lipids - chemistry; Microbiology and Parasitology; Microscopy, Atomic Force - methods; Monolayer; Phenotype; Phospholipids - chemistry; Plankton - metabolism; Proteomics - methods; Pseudomonas aeruginosa; Pseudomonas aeruginosa - metabolism; Spectrometry, Mass, Electrospray Ionization - methods; Temperature
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2010.09.004

Many studies using genetic and proteomic approaches have revealed phenotypic differences between planktonic and sessile bacteria but the mechanisms of biofilm formation and the switch between the two growth modes are not well understood yet. In this study, we focused on inner membrane lipidome modifications when Pseudomonas aeruginosa cells were grown as biofilm. Lipid analyses were performed by Electrospray Ionization Mass Spectrometry. Results showed a drastic decrease of the uneven-numbered chain phospholipids and a slight increase of long chain PEs in sessile organisms as compared with planktonic counterparts, suggesting a better lipid stability in the bilayer and a decrease in membrane fluidity. The impact of sessile growth on lipid domains was then investigated by Brewster Angle Microscopy (BAM) and Atomic Force Microscopy (AFM). Observations showed that inner membrane lipids of P. aeruginosa formed domains when the pressure was close to physiological conditions and that these domains were larger for lipids extracted from biofilm bacteria. This is coherent with the mass spectrometry analyses. ►Pseudomonas aeruginosa lipidome is affected by biofilm growth mode. ►Biofilm growth mode leads to a decrease of the uneven-numbered chain phospholipids. ►Accumulation of long chain lipids is also observed. ►Reconstituted lipid monolayers show larger condensed domains with sessile bacteria.