Asymmetric pore distribution and loss of membrane lipid in electroporated DOPC vesicles
Asymmetric pore distribution and loss of membrane lipid in electroporated DOPC vesicles
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DOI：
10.1016/s0006-3495(01)75754-2
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发表时间：
2001-08-01
影响因子：
3.4
通讯作者：
Chock, PB
中科院分区：
文献类型：
--
作者：
Tekle, E;Astumian, RD;Chock, PB
跨囊泡的外部电场会导致膜的短暂穿孔。使用标准荧光显微镜，使用1，2-二-油酰基-sn-甘油基-3-磷酸胆碱（DOPC）磷脂囊泡检查这些孔的分布和寿命。囊泡膜用荧光膜染料染色，并且在现场应用时，在面向负电极的囊泡膜处观察到直径类似于7 μ m的单个膜孔。在面向阳极的半球，很少发现大的和可见的孔隙，但数据暗示了许多小孔的形成。前和后场荧光囊泡图像，以及从负染色的电子显微照片的图像的分析表明，孔的形成与囊泡膜的磷脂双层的部分损失。由于孔的形成，可能损失高达14%的膜表面。有趣的是，尽管观察到的孔的尺寸分布存在明显差异，但两个半球的有效多孔面积大致相等。进入穿孔囊泡的Ca 2+流入测量进一步表明，孔基本上在脉冲后165 ms内重新密封。在这项研究中发现的孔隙分布与早期的假设（E。特克尔河D. Astumian和P. B. Chock，1994，Proc. Natl. Acad. Sci. U.S.A. 91：11512-11516），其基于各种荧光标记物跨电穿孔膜的选择性转运而具有不对称孔分布。
An externally applied electric field across vesicles leads to transient perforation of the membrane. The distribution and lifetime of these pores was examined using 1,2-di-oleoyl-sn-glycero-3-phosphocholine (DOPC) phospholipid vesicles using a standard fluorescent microscope. The vesicle membrane was stained with a fluorescent membrane dye, and upon field application, a single membrane pore as large as similar to7 mum in diameter was observed at the vesicle membrane facing the negative electrode. At the anode-facing hemisphere, large and visible pores are seldom found, but formation of many small pores is implicated by the data. Analysis of pre- and post-field fluorescent vesicle images, as well as images from negatively stained electron micrographs, indicate that pore formation is associated with a partial loss of the phospholipid bilayer from the vesicle membrane. Up to similar to 14% of the membrane surface could be lost due to pore formation. Interestingly, despite a clear difference in the size distribution of the pores observed, the effective porous areas at both hemispheres was approximately equal. Ca2+ influx measurements into perforated vesicles further showed that pores are essentially resealed within similar to 165 ms after the pulse. The pore distribution found in this study is in line with an earlier hypothesis (E. Tekle, R. D. Astumian, and P. B. Chock, 1994, Proc. Natl. Acad. Sci. U.S.A. 91:11512-11516) of asymmetric pore distribution based on selective transport of various fluorescent markers across electroporated membranes.