Influence of aminoglycoside antibiotics on the thermal behaviour and structural features of DPPE-DPPG model membranes.
The effects of three aminoglycosides (AGs), tobramycin, streptomycin and spectinomycin on 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE)-1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-1-glycerol] (DPPG)/water systems with 0.05 and 0.2 DPPG/DPPE+DPPG molar fractions were examined by using differential scanning calorimetry (DSC), simultaneous small- and wide-angle X-ray scattering (SWAXS), and freeze-fracture transmission electronmicroscopy (FF-TE) at 10(-1) AG/lipid molar ratio in the doped systems. The effects induced by the AGs strongly depend on DPPG/DPPE+DPPG molar fraction. In the presence of the AGs regular lyotropic structures form as opposed to the complex and badly correlated layer structures of the pure 0.2 DPPG/DPPE+DPPG molar fraction system. The investigated AGs possess different structural and thermotropic effects: tobramycin and streptomycin which are true aminoglycosides decrease the main transition enthalpy in both model systems and induce the formation of correlated layer arrangements, while the occurrence of spectinomycin, a non-aminoglycoside aminocyclitol still ranked as an AG, results in a hexagonal phase as it can be deduced from the SAXS patterns and visually observed in the electronmicrographs.
Oszlánczi
Agnes
A
Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, Hungary.
Bóta
Attila
A
Klumpp
Erwin
E
D000617:Aminoglycosides / Q000737:chemistry / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002152:Calorimetry, Differential Scanning; D005614:Freeze Fracturing; D008567:Membranes, Artificial; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D044367:Phase Transition / Q000187:drug effects; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry*; D053838:Scattering, Small Angle; D000198:Spectinomycin / Q000737:chemistry / Q000494:pharmacology; D013499:Surface Properties / Q000187:drug effects; D013696:Temperature; D014961:X-Ray Diffraction
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D008567:Membranes, Artificial; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; D000198:Spectinomycin; C030345:1,2-dipalmitoylphosphatidylglycerol