Precise Size Determination of Amphotericin B and Nystatin Channels Formed in Erythrocyte and Liposomal Membranes Based on Osmotic Protection Experiments
Precise Size Determination of Amphotericin B and Nystatin Channels Formed in Erythrocyte and Liposomal Membranes Based on Osmotic Protection Experiments
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DOI：
10.2116/analsci.24.1551
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发表时间：
2008-12-01
影响因子：
1.6
通讯作者：
Nakao, Satoshi
中科院分区：
文献类型：
--
作者：
Katsu, Takashi;Okada, Shiho;Nakao, Satoshi
细胞裂解的胶体渗透性质可以通过向外部介质中添加适当大小的渗透保护剂来防止。我们引入了无机和有机电解质作为保护剂，以确定多烯类抗生素、两性霉素B和制霉菌素以及迄今广泛用于此目的的糖的精确通道大小。由于胶体渗透细胞溶解表现为溶血前小离子(如K(+))膜通透性障碍的丧失，我们首先通过光纤光谱仪与K(+)选择电极相结合的方法同时监测了两性霉素B诱导的K+外流和溶血的时间响应。在这个实验的基础上，我们用修正的斯托克斯定律计算的水合离子半径和糖的半径来估算红细胞膜上形成的多烯类抗生素的通道大小。两性霉素B和制霉菌素形成的通道半径在0.36-0.37 nm范围内很窄。使用含有胆固醇或麦角甾醇的钙黄绿素脂质体进行了类似的实验，并发现在这些脂膜中形成的通道的半径也与在红细胞膜中形成的通道的半径相同。目前的结果表明，引入水合离子的大小可以提供比单独使用糖更精确的通道大小。
The colloid osmotic nature of the cell lysis can be prevented by adding osmotic protectants of appropriate sizes to the outer medium. We introduced inorganic and organic electrolytes as protectants to determine the precise channel sizes of the polyene antibiotics, amphotericin B and nystatin, in addition to the Sugars so far widely used for this Purpose. Because colloid osmotic cell lysis is evidenced by the loss of membrane permeability barriers for small sizes of ions, such as K(+), preceding hemolysis, we firstly Simultaneously monitored the time response of the K+ efflux and hemolysis induced by amphotericin B by combining a fiber-optic spectrometer with a K(+)-selective electrode. Based on this experiment, we evaluated the sizes of channels of the polyene antibiotics formed in the erythrocyte membrane using the radii of hydrated ions calculated from a modified Stokes' law, as well as the radii of sugars. The radii of channels formed by amphotericin B and nystatin were found to be in a very narrow range of 0.36 - 0.37 nm. Similar experiments were performed using, calcein-loaded liposomes containing cholesterol or ergosterol, and the radii of channels formed in these liposomal membranes were also found to be the same as when formed in an erythrocyte membrane. The present results demonstrated that introducing the sizes of hydrated ions can afford a more precise channel size than the use of sugars alone.