The combined action of low-frequency electromagnetic field and cadmium on natural biopolymers
In this paper the mechanisms of structural changes of human serum albumin (HSA) molecules and of DNA isolated from human whole blood, with addition of cadmium ions in concentration of up to 10<sup>2</sup> safe ranges level, were studied by the fluorescent analysis method. At cadmium ions concentrations ranging from 0.5 µg/ml to 2.5 µg/ml, there were structural changes of DNA molecules in the solution, leading to amplification of fluorescence of the nitrogenous bases. It was shown that after the exposure of electromagnetic field at frequency ranging from 5 to 30 Hz and with intensity of 24-40 A/m to DNA solutions in the presence of cadmium ions, we could observe more considerable amplification of fluorescence (by 2-2.3 times) in comparison with the control solutions. It was suggested that cadmium ions were incorporated into DNA duplex, acting as an intercalating agent, that resulted in fluorescence amplification. The tryptophanic HSA fluorescence quenching with cadmium densification in the solution is indicative of the single-stage type of denaturation - decondensation of proteinaceous globules. The conclusion was drawn that the second stage - full unfolding of HAS aminoacidic chain under the action of cadmium - did not happen.