Stockert J C
Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain.
Acta Histochem. 1989;87(1):33-42. doi: 10.1016/S0065-1281(89)80028-5.
If used as co-solutes in concentrated solutions of cationic planar dyes, caffeine, o-phenanthroline, and tannin induce striking hyperchromic and bathochromic shifts in their absorption spectra. Likewise, the fluorescence of acridine orange at high concentration greatly increases in the presence of caffeine, the emission peak appearing at a shorter wave-length. These spectral changes, which are similar to those produced by organic solvents, detergents, and alpha-cyclodextrin, reflect the disaggregating (monomerizing) capacity of the co-solutes on stacked chromophores. After washing with saturated solutions of caffeine or o-phenanthroline, the chromatin fluorescence by intercalating fluorochromes is reduced or abolished, which suggests competition effects for intercalative binding modes. These results support the use of caffeine, o-phenanthroline, and tannin in spectroscopic and histochemical studies of dye-stuff interactions with DNA and chromatin.
如果咖啡因、邻菲罗啉和单宁在阳离子平面染料的浓缩溶液中用作共溶质，它们会在其吸收光谱中引起显著的增色和红移。同样，在咖啡因存在下，高浓度吖啶橙的荧光会大大增加，发射峰出现在较短波长处。这些光谱变化与有机溶剂、去污剂和α-环糊精产生的变化相似，反映了共溶质对堆叠发色团的解聚（单体化）能力。用咖啡因或邻菲罗啉的饱和溶液洗涤后，嵌入荧光染料的染色质荧光会减弱或消失，这表明对嵌入结合模式存在竞争效应。这些结果支持咖啡因、邻菲罗啉和单宁在染料与DNA和染色质相互作用的光谱学和组织化学研究中的应用。
