| Popis: |
The cephalosporins are bactericidal with both gram-positive and gram-negative activity widely prescribed because of their broad spectrum. Even though most of these antibiotics appear to penetrate the outer membrane through porin proteins, we investigated, as a primary step, the interaction at the water-lipid interface. The information of the intrinsic property of these drugs in permeate or simply interact with phospholipid bilayers becomes of great importance for a better understanding of the functions of a lipid component in the membrane translocation. For that, the structural order of lipid membranes was investigated by measuring fluorescence polarization of membrane-bound fluorophores such as 1,6-phenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluene sulfonate (TMA-DPH) in the presence and absence of different cephalosporin generations as a function of temperature. Location studies have been also carried out using electron paramagnetic resonance (EPR) spectroscopy, valuable tool for collecting information on the dynamics of lipids and membrane structure. The results obtained suggest that the incorporation of these antibiotics into DMPC and DMPG bilayer does not significantly modify their transition temperature whereas perceptible changes in the cooperativity of the phospholipid transition are observed. |
