Figure 7: The effect of increasing concentrations of spermine and spermidine on the quenching of YOYO fluorescence bound to gcDNA and mDNA. and are the fluorescence intensities of the dye in the presence of DNA before and after the addition of amines, respectively. (a) Spermidine. (b) Spermine. (1) and (2) are the results in gcDNA and mDNA in Hepes buffer, pH 7.4 containing 100 mM NaCl. Dye to DNA-phosphate ratio 1 : 50. Fluorescence setup: excitation, 485 nm; emission 505 nm. Temperature 20°C.