Raman Spectroscopy Of The Uv Radiation On Dna Damage And Its Protection

Ultraviolet radiation not only affects crops, but also does harms to humans. So it is necessary to study the effects of ultraviolet radiation on DNA and find what can protect DNA when it is ultraviolet radiated. Raman spectra of the calf thymus DNA with different wavelength ultraviolet radiation were reported. In the other way, the effects of different levels of vitamin C on UV radiation-induced DNA damage were studied too. We have made several attempts that be reported in this thesis.1. DNA in aqueous solution was ultraviolet radiated 9min and 20min respectively. The experimental results proved that through the ultraviolet radiation time was short, ultraviolet radiation had a serious influence on DNA. When the time of UV radiation is 9 minutes, the peak in 1094cm'1 changed into four weaker peaks, and it implied that the molecular conformations are changed and the hydrogen bonds are damaged. Some kinds of nucleotides came into being because of the damage of DNA molecular. Purine and pyrimidine bases were badly damaged. 20min UV radiation damage DNA completely.2. DNA in aqueous solution was UVA&UVB radiated 1 hour and 3 hours respectively. The change in the DNA molecule with UVA&UVB radiation is far less than that with the whole ultraviolet radiation. But when the time of UVA&UVB radiation was long, DNA was also damaged. Pyrimidine bases and deoxyribose were damaged first.3. DNA in aqueous solution was UVA radiated 2 hours and 16 hours respectively. The effects of UVA radiation to DNA were most slight. The bases were damaged slightly. A type structure of DNA remained changing in aqueous solution with UVA radiation.4. The Raman spectra of DNA in different levels of Vitamin C with 10min ultraviolet radiation and 30min ultraviolet radiation were reported. The experimental results proved that vitamin C can reduce DNA damage solely, but the effects were depended on the concentration of vitamin C. When the concentration of vitamin Cwas lower than 0.35m mol/L, DNA was protected well with the rising of vitamin C's concentration during ultraviolet radiation. DNA was protected best when vitamin C was 0.35m mol/L. When vitamin C's concentration was higher than 0.35m mol/L, vitamin C accelerated DNA damage with lOmin ultraviolet radiation. The principle that DNA was protected was discussed.