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RESEARCH PRODUCT

Impact of Plesiomonas Shigelloides Strain CNCTC 144/92 Lipopolysaccharide on DPPC Liposome Membranes: EPR Method

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Membrane fluidity measurements were performed for synthetic DPPC liposomes sonicated in aqueous solution and doped by Plesiomonas shigelloides strain CNCTC 144/92 (serotype O74:H5) lipopolysaccharide (LPS) extracted from the phenol (LPSPhOH) and water (LPSH2O) phases. Concentrations of LPS in relation to DPPC ranged from 0 to 1.4% (molar ratio). The EPR spin probe method was used to describe physicochemical properties of different regions of the lipid bilayer. Since TEMPO spin probe dissolves both in the hydrophobic region of the membrane and in an aquatic environment it is possible to determine the spectroscopic partition parameter F, indicating the changes that occur in the water-lipid interface. The 16-DOXYL probe distributed in the middle of the lipid bilayer makes it possible to obtain the rotational correlation time τ parameter, which provides information about fluidity changes in the liposome membrane. Here we report that increasing concentrations (mainly in the range of 0.4-0.8%) of investigated LPSPhOH and LPSH2O significantly influence spectroscopic parameters (F and τ). The surface area of the DPPC liposomes membranes was affected predominantly by LPSH2O while the lipid bilayer was most influenced by LPSPhOH.