Cholesterol in condensed and fluid phosphatidylcholine monolayers studied by epifluorescence microscopy.
Cholesterol in condensed and fluid phosphatidylcholine monolayers studied by epifluorescence microscopy.
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通过落射荧光显微镜研究浓缩和液体磷脂酰胆碱单层中的胆固醇。
DOI：
10.1016/s0006-3495(97)78900-8
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发表时间：
1997
影响因子：
3.4
通讯作者：
K. Keough
中科院分区：
文献类型：
--
作者：
L. D. Worthman;K. Nag;Philip J. Davis;K. Keough
在2 - 1 +/-2 ℃下，使用1 mol% 1-棕榈酰-2-[12-[（7-硝基-2-1，3-苯并恶二唑-4-基）氨基]十二烷酰基]磷脂酰胆碱（NBD-PC）作为荧光团，使用落射荧光显微术研究胆固醇对二棕榈酰磷脂酰胆碱（DPPC）和1 -棕榈酰-2-油酰磷脂酰胆碱（POPC）单层的影响。高达30摩尔%的胆固醇在DPPC单层的探针排除的液体凝聚（LC）相在所有的表面压力（PI）的量减少，但没有影响的POPC，这仍然在液体膨胀（LE）相在所有的PI的单层。在低pi（2-5 mN/m）下，DPPC中的10mol%或更多胆固醇诱导侧向相分离成暗探针排除区和亮探针富集区。在POPC单层中，当存在>或=40 mol%或更多胆固醇时，在低pi下观察到相分离。在这些脂质单层中观察到的胆固醇浓度增加的横向相分离可能是富含胆固醇的结构域在优先排除荧光探针的有序流体相中分离的结果。随着pi的增加，单层细胞可以从异质的深色和浅色外观转变为均匀的荧光相，其方式取决于pi和胆固醇含量。酰基链的堆积密度可能是胆固醇与磷脂酰胆碱（PC）相互作用的决定因素，因为在具有相似分子面积的磷脂（PL）/甾醇混合物中观察到单层表面纹理的转变。在高pi（41 mN/m）下，在含有80-100 mol%胆固醇的单分子膜中观察到伸长的晶体样结构，并且当单分子膜在塌陷后被压缩时，这些结构的尺寸增大。该观察结果可能与单层塌陷后胆固醇的分离和结晶有关。
Epifluorescence microscopy was used to investigate the effect of cholesterol on monolayers of dipalmitoylphosphatidylcholine (DPPC) and 1 -palmitoyl-2-oleoyl phosphatidylcholine (POPC) at 21 +/- 2 degrees C using 1 mol% 1-palmitoyl-2-[12-[(7-nitro-2–1, 3-benzoxadizole-4-yl)amino]dodecanoyl]phosphatidylcholine (NBD-PC) as a fluorophore. Up to 30 mol% cholesterol in DPPC monolayers decreased the amounts of probe-excluded liquid-condensed (LC) phase at all surface pressures (pi), but did not effect the monolayers of POPC, which remained in the liquid-expanded (LE) phase at all pi. At low pi (2–5 mN/m), 10 mol% or more cholesterol in DPPC induced a lateral phase separation into dark probe-excluded and light probe-rich regions. In POPC monolayers, phase separation was observed at low pi when > or=40 mol% or more cholesterol was present. The lateral phase separation observed with increased cholesterol concentrations in these lipid monolayers may be a result of the segregation of cholesterol-rich domains in ordered fluid phases that preferentially exclude the fluorescent probe. With increasing pi, monolayers could be transformed from a heterogeneous dark and light appearance into a homogeneous fluorescent phase, in a manner that was dependent on pi and cholesterol content. The packing density of the acyl chains may be a determinant in the interaction of cholesterol with phosphatidylcholine (PC), because the transformations in monolayer surface texture were observed in phospholipid (PL)/sterol mixtures having similar molecular areas. At high pi (41 mN/m), elongated crystal-like structures were observed in monolayers containing 80–100 mol% cholesterol, and these structures grew in size when the monolayers were compressed after collapse. This observation could be associated with the segregation and crystallization of cholesterol after monolayer collapse.
影响因子：
2.9
作者：
S. Lund-Katz;H. Laboda;L. McLean;M. Phillips
通讯作者：
S. Lund-Katz;H. Laboda;L. McLean;M. Phillips
影响因子：
6.5
作者：
J. J. Collins-J.;M. Phillips
通讯作者：
J. J. Collins-J.;M. Phillips
甲基化对磷脂酰乙醇胺单层微域结构的影响。
影响因子：
3.4
作者：
Yu,H;Hui,SW
通讯作者：
Hui,SW