title: Effect of surface curvature on the interaction of single lamellar phospholipid vesicles with aromatic and nonaromatic heptaene antibiotics (vacidin A and amphotericin B).
abstract: The interactions of unilamellar lipid vesicles with vacidin A, an aromatic heptaene antibiotic, and with amphotericin B, a nonaromatic heptaene antibiotic were compared. Uptake of both antibiotics, monitored by circular dichroism, was found to be faster with small vesicles than with large ones. By combining permeability measurements (Gary-Bobo and Cybulska, J. Antibiotics 35, 1068 (1982)) and circular dichroism spectra, we found that for vacidin A, the same permeability inducing species is formed regardless of vesicles size. However, at a given concentration of antibiotic, less of the permeability inducing species is formed in the presence of small vesicles than in the presence of large vesicles. This may account for the differences between small and large vesicles in antibiotics-induced permeability. For amphotericin B, the permeability inducing species formed in the presence of small vesicles differs from that formed in the presence of large vesicles.
mesh_terms: D000666:Amphotericin B; D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D002174:Candicidin / Q000031:analogs & derivatives; D002942:Circular Dichroism; D008081:Liposomes; D008968:Molecular Conformation; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D013053:Spectrophotometry
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D008081:Liposomes; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D002174:Candicidin; C031985:vacidin A; D000666:Amphotericin B