FLIJORESCENCE STUDIES OF NUCLEOPROTEINS 



115 



nucleotides possess characteristic fluorescence spectra. The fluorescence 

 of the nucleic acids covers the spectral region of emission of their l)ases 

 and the difference in fluorescence of RNA and DNA is determined pre- 

 dominantly l)y the spectra of thymhie and uracil. 



440 



A (rr.ii) 



Fig. 5. — Fluorescence spectra of deoxyribonucleic acid (from the erythrocytes of hens) 

 and of its component bases (excitation with A — 260 to 280 m/u). 

 A-adenine, G-guanine, C-cytosine, T-thymine. 



ULTRAVIOLET FLUORESCENCE MICROSCOPY 



In 1956 Brumberg described a new method of fluorescence micros- 

 copy which allowed one to photograph the it.v. fluorescence of micros- 

 scopic objects. He made the assumption that the monotonous blue or 

 violet autofluorescence of the majority of biological objects are the 

 "tails" in the visible spectrum of a fluorescence of which the peaks are 

 located in the u.v. region. This assumption has been confirmed. It was 

 found that many tissues of plant and animal organisms possess charac- 

 tei'istic and definitely expressed u.v. fluorescence (Brumberg et al., 

 1958; Barsky et al., 1959). The version of fluorescence microscopy in 

 which excitation and recording of fluorescence is carried out in the u.v. 

 region is called u.v. fluorescence microscopy. 



Recently Brumberg and Barsky (1960) have described the application 

 of the method to investigations of cytological objects. In this study, 

 as well as in further investigations, the same site of the preparation was 

 consecutively photographed in ultraviolet light, first in the light of its 

 own u.v. fluorescence (on excitation by incident light coming through 



