Collini Maddalena, D'Alfonso Laura, Baldini Giancarlo
Dipartimento di Fisica, Universita di Milano-Bicocca, Milano, Italy.
Photochem Photobiol. 2003 Apr;77(4):376-82. doi: 10.1562/0031-8655(2003)077<0376:tcoteh>2.0.co;2.
The fluorescence lifetime of ethidium bromide (EB), a widely used fluorescent dye, has been monitored in water solution versus trehalose concentration in order to learn how the presence of the disaccharide modifies the hydration of EB, which is used in this study as a model probe. The interest in trehalose, a naturally occurring bioprotector (osmolyte), stems from its ability to stabilize biomolecules under stress situations. The observed effects of trehalose on EB fluorescence properties have been compared with those induced by sucrose and glucose. Lifetime measurements have been performed by frequency domain fluorometry (2-40 MHz), and from the analysis of their changes versus sugar concentration, the EB-sugar interaction parameters have been obtained. The effect of trehalose on the EB decay in glasses has also been studied both by exploring the heterogeneity of lifetime decay and by single-molecule imaging. Trehalose appears to be more efficient in changing the EB fluorescence parameters, such as the emission lifetime, and it leads to a degree of heterogeneity higher than that induced by the other sugars. When EB is embedded in trehalose glasses, the heterogeneity of the emission and of the bleaching time is further enhanced.
溴化乙锭（EB）是一种广泛使用的荧光染料，为了了解双糖的存在如何改变EB的水合作用（本研究中用作模型探针），在水溶液中监测了其荧光寿命与海藻糖浓度的关系。对海藻糖（一种天然存在的生物保护剂（渗透剂））的兴趣源于其在应激情况下稳定生物分子的能力。已将观察到的海藻糖对EB荧光特性的影响与蔗糖和葡萄糖诱导的影响进行了比较。通过频域荧光法（2 - 40 MHz）进行了寿命测量，并根据其随糖浓度的变化分析，获得了EB - 糖相互作用参数。还通过探索寿命衰减的异质性和单分子成像研究了海藻糖对玻璃态中EB衰减的影响。海藻糖在改变EB荧光参数（如发射寿命）方面似乎更有效，并且它导致的异质性程度高于其他糖类诱导的程度。当EB嵌入海藻糖玻璃中时，发射和漂白时间的异质性会进一步增强。
