Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry , Jagiellonian University , Gronostajowa 2 , 30-387 Kraków , Poland.
Department of Environmental Chemistry, Faculty of Chemistry , Jagiellonian University , Gronostajowa 2 , 30-387 Kraków , Poland.
Langmuir. 2018 May 1;34(17):5097-5105. doi: 10.1021/acs.langmuir.7b04262. Epub 2018 Apr 20.
An increasing number of bacterial infections and the rise in antibiotic resistance of a number of bacteria species forces one to search for new antibacterial compounds. The latter facts motivate the investigations presented herein and are aimed at studying the influence of a cationic lipid, 1-palmitoyl-2-oleoyl- sn-glycero-3-ethylphosphocholine (EPOPC), on model (mono- and bilayer) membranes. The monolayer experiments involved the analysis of the interactions of EPOPC with bacterial membrane lipids in one component and mixed systems as well as Brewster angle microcopy studies. The properties of liposomes were analyzed based on the results of dynamic light scattering (DLS) and zeta potential measurements as well as on the experiments concerning the release of calcein entrapped in liposomes after titration with surfactant solution and steady-state fluorescence anisotropy of DPH. The obtained results evidenced that EPOPC, even at low concentrations, strongly changes organization of model systems making them less condensed. Moreover, EPOPC decreases the hydrodynamic diameter of liposomes, increases their zeta potential, and destabilizes model membranes, increasing their fluidity and permeability. Also, the in vitro tests performed on Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) strains prove that EPOPC has some bacteriostatic properties which seem to be stronger toward Gram-negative than Gram-positive bacteria. All these findings allow one to conclude that EPOPC mode of action may be directly connected with the interactions of EPOPC molecules with bacterial membranes.
越来越多的细菌感染和一些细菌物种对抗生素耐药性的上升迫使人们寻找新的抗菌化合物。这些事实促使了本文的研究，并旨在研究阳离子脂质 1-棕榈酰基-2-油酰基-sn-甘油-3-乙基磷酸胆碱（EPOPC）对模型（单层和双层）膜的影响。单层实验涉及分析 EPOPC 与细菌膜脂在单一组分和混合系统中的相互作用以及布儒斯特角显微镜研究。基于动态光散射（DLS）和 zeta 电位测量的结果以及关于用表面活性剂溶液滴定后包封在脂质体中的钙黄绿素释放和 DPH 的稳态荧光各向异性的实验，分析了脂质体的性质。所得结果表明，即使在低浓度下，EPOPC 也强烈改变模型系统的组织，使其不那么凝聚。此外，EPOPC 降低了脂质体的水动力直径，增加了它们的 zeta 电位，并破坏了模型膜，增加了它们的流动性和通透性。此外，对大肠杆菌（革兰氏阴性）和金黄色葡萄球菌（革兰氏阳性）菌株进行的体外测试证明，EPOPC 具有一些抑菌特性，似乎对革兰氏阴性菌比对革兰氏阳性菌更强。所有这些发现都可以得出结论，EPOPC 的作用模式可能与 EPOPC 分子与细菌膜的相互作用直接相关。
