STAINING, PRACTICAL AND THEORETICAL 



ACRIDINE GROUP 



Chroniophore: /\/N^^ 



I 



H 



This is a subdivision of the xanthene group. Only about ten acri- 

 dine dyes are used in microscopy. They are all basic dyes of low 

 molecular weight, around 300. All of them are fluorochromes. 

 Some of them (e.g. acriflavine) are used as antiseptics. Atebrin, 

 which is an acridine dye, is also an antimalarial agent. 



Acridine orange is used for differentiating nucleic acids. It is 

 also used in a simple and rapid method {see pages 93-101) for 

 the cytodiagnosis of cancer. 



All the acridine dyes used in microscopy are yellow or orange 

 in ordinary light. In fluorescence microscopy, however, they 

 give polychrome pictures. 



The following are examples of the acridine dyes : 



ACRIDINE ORANGE N 



Michrome No. 87. Molecular weight 302. A basic dye, pH 6 •5*. 



Solubility at 15° C: water 5%, absolute alcohol 0-5%. 



+ 



(HgQaN 



N(CH3)2 



ci- 



ACRIFLAVINE 



Michrome No. 430. Molecular weight 260. A basic dye, pH i -4*. 

 Solubility at 15° C* water 15%, absolute alcohol 1%. 



NH2 



H2N- 



* 1% in neutral distilled water see pp. 17 and 29. 



36 



+ 



CI- 



