Impact of the biofilm mode of growth on the inner membrane phospholipid composition and lipid domains in Pseudomonas aeruginosa.
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.
Benamara
Hayette
H
PBS laboratory, UMR 6270, FR 3038, CNRS, Proteomic Platform of the IFRMP23, University of Rouen, 76821 Mont-Saint-Aignan cedex, France.
Rihouey
Christophe
C
Jouenne
Thierry
T
Alexandre
Stéphane
S
D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms; D002462:Cell Membrane / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D008563:Membrane Lipids / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods; D010641:Phenotype; D010743:Phospholipids / Q000737:chemistry*; D010933:Plankton / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013696:Temperature
D001426:Bacterial Proteins; D005227:Fatty Acids; D008055:Lipids; D008563:Membrane Lipids; D010743:Phospholipids