CHAPTER 17 



Cjrtochemical Techniques for Nucleic Acids* 

 HEWSON SWIFT 



page 



I. Introduction 51 



II. Basic Dj-es 52 



1. Specificity 54 



2. Protein Interference and Effect of pH 56 



3. Fixation 58 



4. Affinity 58 



5. Differentiation 60 



6. Metachromasj' 61 



7. Quantitative Aspects 63 



III. The Feulgen Reaction 65 



1. Chemistry 65 



2. Specificity 67 



3. Localization 69 



4. Fixation 70 



5. Hydrolj'sis 71 



6. Variations in the Feulgen Reagent 73 



7. Quantitative Aspects 74 



IV. Other Cytochemical Reactions 78 



V. Extraction Techniques 78 



1. Acid Extraction 79 



2. Nuclease Extraction 80 



VI. Photometric Methods for Cell Studies 82 



VII. Ultraviolet Absorption 84 



1. Factors Influencing Absorption Curves 84 



2. Interfering Substances 86 



3. Nonspecific Light Loss 86 



VIII. Conclusions 89 



IX. Methods 90 



I. Introduction 



Cytochemistry seeks to interpret the biochemistry of cells in terms of 

 their morphology. A great deal of the current interest in the nucleic acids 



* Supported in part by Grant C-1612 from the National Cancer Institute of the 

 United States Public Health Service, and by the Abbott Memorial Fund. The author 

 wishes to e.xpress his sincere thanks to Dr. E. M. Rasch for providing many of the 

 measurements used in the figures and tables, and also for help in preparing the manu- 

 script. 



51 



