Dapson R W
Dapson & Dapson LLC, 6951 East AB Avenue, Richland, MI 49083, USA.
Biotech Histochem. 2007 Aug;82(4-5):173-87. doi: 10.1080/10520290701704188.
Carmine has been used in biological staining to demonstrate selectively nuclei, chromosomes or mucins, depending on the formulation. Throughout its history in science, complaints and frustrations have been expressed about dye quality. Inconsistencies in dye quality or identity have prevented thorough understanding of staining mechanisms and have caused many stain solutions to behave unsatisfactorily. The aim of this review is to (1) detail causes of these problems, which are rooted in history, geography and production, (2) offer ways to minimize problems and (3) provide modern explanations for stain behavior. Carmine is a "semi-synthetic" dye, i.e., a complex of aluminum and the natural dye cochineal (carminic acid). Carmine shows considerable batch-to-batch variability. Geography, politics, history, agricultural practices and iconography all contribute to the variability of cochineal. In addition, widely divergent manufacturing methods are used to produce carmine. Also, confusion in terminology has led to mislabeling. Pressure from the food industry for a more satisfactory colorant for acidic foods led to the introduction of a new dye, aminocarminic acid, which could enter the biological market inadvertantly. Improved methods of analysis should help the certification process by the Biological Stain Commission. Further standardization could be achieved by replacing most of the methods of solubilizing carmine. The majority of these methods use heat, which is likely to damage the dye molecule. Fortunately, carmine is readily dissolved by raising the pH of the aqueous solvent above 12, and a new form of the dye, now available commercially, is soluble in water without the need for heat or pH adjustment. Chemical structures and physical properties of carminic acid, carmine, aminocarminic acid and kermesic acid are reviewed. A new configuration for carmine is proposed, as well as possible changes to carminic acid and carmine molecules as a result of decomposition caused by heating. Each of the major classes of carmine-based stains is described as are possible mechanisms of attachment to specific substrates. Glycogen binds carmine through hydrogen bonding, and it is here that carmine decomposed by heat could have the greatest detrimental impact. Nuclei and chromosomes are stained via coordination bonds, perhaps supplemented by hydrogen bonds. Finally, acidic mucins react ionically with carmine. Specificity in the latter case may be due to unique polymeric carmine molecules that form in the presence of aluminum chloride.
根据配方不同，洋红已被用于生物染色，以选择性地显示细胞核、染色体或粘蛋白。在其科学发展历程中，人们一直对染料质量表示不满和沮丧。染料质量或特性的不一致阻碍了对染色机制的深入理解，并导致许多染色溶液的表现不尽人意。本综述的目的是：（1）详细阐述这些问题的根源，这些问题源于历史、地理和生产；（2）提供尽量减少问题的方法；（3）为染色行为提供现代解释。洋红是一种“半合成”染料，即铝与天然染料胭脂虫（胭脂红酸）的复合物。洋红在批次之间表现出相当大的变异性。地理、政治、历史、农业实践和图像学都导致了胭脂虫的变异性。此外，生产洋红采用了广泛不同的制造方法。而且，术语的混乱导致了错误标注。食品工业对用于酸性食品的更令人满意的着色剂的压力导致了一种新染料氨基胭脂红酸的引入，它可能会无意中进入生物市场。改进的分析方法应有助于生物染色委员会的认证过程。通过取代大多数溶解洋红的方法可以实现进一步的标准化。这些方法大多使用加热，这可能会损坏染料分子。幸运的是，通过将水性溶剂的pH值提高到12以上，洋红很容易溶解，并且现在市售的一种新形式的染料可溶于水，无需加热或调节pH值。本文综述了胭脂红酸、洋红、氨基胭脂红酸和紫铆酸的化学结构和物理性质。提出了洋红的一种新构型，以及由于加热分解导致的胭脂红酸和洋红分子可能的变化。描述了每一类主要的基于洋红的染色剂以及与特定底物结合的可能机制。糖原通过氢键与洋红结合，在这里，受热分解的洋红可能产生最大的有害影响。细胞核和染色体通过配位键染色，也许还辅以氢键。最后，酸性粘蛋白与洋红发生离子反应。后一种情况下的特异性可能归因于在氯化铝存在下形成的独特的聚合洋红分子。
