QUANTITATIVE STUDY OF THE FEULGEN REACTION 

 VVITH DNA CONTAINING CELLULOSE FILMS 



P. van DUIJN and J. P. PERSIJN 

 Biochemical Section Laboratory for Pathology, Leiden, The Netherlands 



For quantitative study of cytochemical reactions with the aid of mode! 

 substances it is désirable to incorporate such substances in a kind of 

 artificial section. 



In this way the molecular environment of the cotnpound can be modified 

 and the rapid changing of média, as is customary in many staining re- 

 actions, can be imitated. | 



To study the Feulgen reaction, DNA was mixed with viscose (cellulose 

 xanthogenate) and cellulose films were made from this mixture. On such 

 films the Feulgen reaction, with appropriate controls, was carried out. 

 Extinctions were measured while the membranes were in a stretched posi- 

 tion in a spectrofotometer cell, filled with o-xylene. In this way the 

 spectrum of the DNA-Schiff complex could be determined. 



At the site where the lightbeafn of the spectrofotometer had traversed 

 the film, a part of the film of known surface area was punched out. 



The punches were dried, weighed and analysed for DNA-P. In this 

 way the extinction measured could be corrected for local variations in 

 thickness of the films and for loss of DNA from the films during the Feul- 

 gen procédure. 



Results on the relation between the extinction measured and the DNA 

 content after staining will be presented. 



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