Fluorescence of Tb3 complexes with metaphase chromosomes of mink fibroblasts

The fluorescence of the Tb3+ complex with metaphase chromosomes of mink fibroblasts was studied. It was shown that the fluorescence intensity of this complex is 6.5 times as high as that of the Tb3+-native DNA complex. The fluorescence of the chromosome-Tb3+ complex is predominantly determined by chromosomal DNA. The high intensity of fluorescence may be due to partial disturbances in the secondary structure of DNA during folding of the metaphasic chromosome.