Parasassi T, De Stasio G, Miccheli A, Bruno F, Conti F, Gratton E
Istituto di Medicina Sperimentale, CNR, Roma, Italy.
Biophys Chem. 1990 Jan;35(1):65-73.
Changes in the thermal behavior of DMPC (dimyristoyl-L-phosphatidylcholine) and an equimolar mixture of DMPC and DMPE (dimyristoyl-L-phosphatidylethanolamine) induced by the plant hormone abscisic acid (ABA) have been investigated using fluorescent probes. The fluorescence decay of the hydrophobic probe 1,6-diphenyl-1,3,5-hexatriene (DPH) in these vesicles has been measured using frequency-domain fluorometry, and has been analyzed using both models of discrete exponential components and continuous lifetime distributions. In the DMPC vesicles, using the distributional approach, higher center and width values were observed in the presence of abscisic acid (ABA), indicating a decrease in the dielectric constant of the lipid phase that we attribute to a decrease in the water concentration within the bilayer. Moreover, the presence of ABA in the liposomes increased the phospholipid phase transition temperature. The addition of ABA to the DMPC/DMPE mixture strongly increased the microheterogeneity of the system as reported by the FWHM (full-width at half-maximum) of the distributional approach.
利用荧光探针研究了植物激素脱落酸（ABA）诱导的二肉豆蔻酰-L-磷脂酰胆碱（DMPC）以及DMPC与二肉豆蔻酰-L-磷脂酰乙醇胺（DMPE）等摩尔混合物热行为的变化。使用频域荧光法测量了这些囊泡中疏水探针1,6-二苯基-1,3,5-己三烯（DPH）的荧光衰减，并使用离散指数成分模型和连续寿命分布模型进行了分析。在DMPC囊泡中，采用分布方法，在脱落酸（ABA）存在的情况下观察到更高的中心值和宽度值，这表明脂质相介电常数降低，我们将其归因于双层内水浓度的降低。此外，脂质体中ABA的存在提高了磷脂的相变温度。如分布方法的半高宽（FWHM）所报告，向DMPC/DMPE混合物中添加ABA会强烈增加系统的微观不均匀性。
