FLUORESCENCE STUDIES OF POLYUNSATURATED PHOSPHOLIPID MEMBRANES

多不饱和磷脂膜的荧光研究

• 批准号: 3767562
• 负责人: N SALEM
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3767562
• 关键词: alcoholism /alcohol abuse; calorimetry; drug withdrawal; ethanol; fluorescent dye /probe; laboratory rat; lipid bilayer membrane; membrane activity; membrane lipids; microsomes; phospholipids; unsaturated fatty acids

Alcohol-induced depletion of polyunsaturated lipids alters the physical and functional properties of biological membranes. Chronic alcohol exposure is known to cause resistance to ethanol-induced membrane disordering measured in vitro. Fluorescence studies in our laboratory confirm that this response recovers 2 to 3 days post-withdrawal in rat liver microsomes. Bulk membrane "fluidity" measurements with DPH detect no difference in basal membrane order between controls and liver microsomes from the withdrawal group. However, a localized membrane probe, TMA-DPH, detected a significantly higher basal membrane order in the 24 hours post-withdrawal group. Motions of fluorescent probes localized in specific areas of these bilayers suggest that alcohol-induced changes in lipid composition affect membrane organization in very distinct lipid domains. Furthermore, our laboratory has shown that alcohol depletes the long chain polyunsaturated fatty acids such as 20:4n6 and 22:6n3 from membranes. We hypothesize that there is a specialization in the localization and function of the 22:6-phospholipids in biological membranes. To test this hypothesis, the physical environment of 22:6n3 and other polyunsaturated phospholipids have been studied using fluorescence anisotropy and differential scanning calorimetry of membrane preparations. We have found that under defined conditions, bilayers containing 22:6n3 species become more highly packed than bilayers containing species with fewer double bonds. However, correlation times of the same labeled samples indicate that the local environment along the fatty acyl chains becomes increasingly disordered with increasing unsaturation.

酒精诱导的多不饱和脂质的消耗改变了身体的 和生物膜的功能特性。 慢性酒精 已知暴露会引起对乙醇诱导的膜的抗性 在体外测量的无序。 我们实验室的荧光研究 证实该反应在大鼠停药后2 - 3天恢复 肝微粒体 使用DPH检测的整体膜"流动性"测量 对照组和肝脏之间的基底膜顺序无差异 停药组的微粒体。 然而，一个局部的膜 探针TMA-DPH检测到一个显著较高的基底膜顺序， 停药后24小时组。 荧光探针的运动 位于这些双层的特定区域表明，酒精诱导的 脂质组成的变化影响膜组织， 脂质结构域。 此外，我们的实验室表明，酒精 消耗长链多不饱和脂肪酸如20：4N6， 22：6n3从膜。 我们假设有一个专业化， 22：6-磷脂在生物体内的定位和功能 膜。 为了验证这一假设，22：6n3的物理环境 和其他多不饱和磷脂已经研究了使用 膜的荧光各向异性和差示扫描量热法 准备工作 我们已经发现，在确定的条件下， 含有22：6n3的物种变得比双层更高度堆积 含有双键较少的物质。 然而， 相同的标记样本指示沿着 脂肪酰基链变得越来越无序， 不饱和度