RIBOFLAVIN AND POLYSACCHARIDES 43 



RIBOFLAVIN 



The detection of riboflavin in tissue sections, based on reduction 

 of the vitamin in acid medium to leucoflavin and reoxidation to 

 bright red granules of rhodoflavin, was employed by Chevremont 

 and Comhaire ( 1939) . Riboflavin can be recognized in tissue by its 

 characteristic greenish-yellow fluorescence when irradiated with 

 ultraviolet (page 104). 



Chevremont and Comhaire Method for Rihoflavin 



SPECIAL REAGENTS 



Fixative. Formol-Nitron or formol-basic lead acetate soln. 

 Reductant Solution. Add zinc to hydrochloric acid to generate 



hydrogen. 

 Oxidant Solution. Dilute hydrogen peroxide. 



PROCEDURE 



1. Fix tissue for 5 days and prepare sections. 



2. Treat sections for 30 min. with reductant soln. 



3. Ptinse in water and treat with oxidant soln. 



4. Examine under microscope. 



Result. Bright red granules indicate presence of riboflavin. The 

 localizations are probably unreliable due to the diffusibility of the 

 riboflavin and its derivatives. 



POLYSACCHARIDES IN GENERAL 



A general reaction for the microscopic visualization of polysac- 

 charides has been described by Hotchkiss (1946).* The reaction 

 involves the oxidation of adjacent hydroxyl groups to aldehydes by 

 means of periodate, and the coloring of the aldehyde with Feulgen 

 reagent. The oxidation takes place according to the equation: 



— CHOH— CHOH— + HsIOe > — CHOHCO— + HIO3 + 3 H2O 



The chief substances in plant tissues that show the stain are 

 starches, cellulose, hemicelluloses, and pectins and, in animal tissues, 

 glycogen, mucin, mucoproteins, and presumably hyaluronic acid 

 and chitin. The pentoses of nucleic acid are so substituted that they 



* Subsequent to this writing the author learned of the paper of McManus 

 (1946) (Bibliography Appendix, Ref. 13) in which the same principal was 

 independently presented. 



