| DNA is the germ plasm of the organism,owner of hereditary information and the material elements of gene expression,and DNA plays a vary important part in the natural being movement(biology growth,development and reproduce)and abnormity being movement(cancerous breakand cancerous movement).The quantitative analysis,differential identification of DNA plays a good part in the genomy,virus and molecule biology.The quantitative analysis is the basement to search DNA,but because the inner fluorescence of DNA is very weak,so the determination of DNA comes in for restrict using fluorescence of DNA directly.Ethidium bromide(EB)is the pioneer fluorescence probe,it not only can be apllied in the quantitative and qualitative analysis of nucleic acid,but also can be used in the dynamics characteristic study of nucleic acid,but EB is a carcinogen,which limit its application,so people begin to search new fluorescence probe of DNA.Now,people have done lots of work, the synthesis and utilization of more sensitive probe,which at the same time can avoid background disturbance of biology fluorescence,is the searching hotpot.Some work on the basement of pioneer's work and some evolvement on the DNA fluorescence probe are reported in this paper.This thesis consists of four sections as follows:First,fluorescence,absorption and circular dichroism spectra have been used in the interactions of ruthenium(Ⅲ),rhodium(Ⅲ)and palladium(Ⅱ)ions with DNA with berberine as a probe.The results are as follows:ruthenium(Ⅲ)and rhodium(Ⅲ) ions show different effects from that of the palladium(Ⅱ)ion on the fluorescence spectra characteristics of berberine-DNA system.Quenching fluorescence is seen with palladium(Ⅱ)ion addition,whereas increasing fluoresence is observed for ruthenium(Ⅲ)and rhodium(Ⅲ)ions.The addition of ruthenium(Ⅲ),rhodium(Ⅲ) and palladium(Ⅱ)ions causes the increasing absorption of the DNA solution.The addition of ruthenium(Ⅲ),rhodium(Ⅲ)and palladium(Ⅱ)ions to the DNA solution also causes the circular dichroism spectra to change.The above results suggest that different metal ions exhibit different affinity when binding to DNA,which could correlate well with the ions' charge,structure and the ability to coordinate.There is a comparison between Pt(Ⅳ)and Pd(Ⅱ)ions on the fluorescence of the berberine-DNA ??system.Second,the spectroscopy interactions between berberine and DNA,ethidium bromide(EB)and DNA have been studied by UV-absorption,fluorescence,circular dichroism spectroscopy and agarose gel electrophoresis methods.When DNA exists, the fluorescence intensity of berberine and EB both have a great increase(pH=7.01, CDNA/CBer=9,F/Fo=60,CDNA/CEB=9,F/Fo=69.5),but the change of pH value has not great effect on the wavelength and intensity of the fluorescence spectra.The absorbance of UV spectra present a hypochromic effect when DNA concentration increasing(CDNA/CBer=10,Ao/A=1.2078,CDNA/CEB=0.5,Ao/A=1.2123).The CD spectra of DNA has a great change both in negative and positive spectra (CDNA/CBer=60,θ/θo=1.228,CDNA/CEB=60,θ/θo=1.426),In the agarose gel electrophoresis,the luminescence intensity of EB-DNA system is more sensitive than berberine-DNA system,so we implore the UV-absorption,fluorescence,circular dichroism spectroscopy and agarose gel electrophoresis methods to study the interaction of EB and berberine on DNA.In the quantitative determination of DNA, we could implore the berberine rather than the EB,which offer us an important base of new reagent in the quantitative determination of DNA,which also afford us clue to search more sensitive probe of DNA.Third,an acetylthiourea compound was synthesized by rebuilding EB,the structure of the compound was characterized by IR,1H NMR spectrum and elemental analysis.The thiourea has good fluorescence.Spectroscopy methods had been used in the interactions of thiourea with ct-DNA.When DNA exists,the fluorescence intensity increased.The ultraviolet absorption intensity of thiourea present a hypochromic effect when DNA concentration increasing.The positive spectra of CD spectrum of ct-DNA had an increasement,and the negative spectra has a decreasement.So we implore the fluorescence,UV-absorption and circular dichroism spectroscopy methods to study the interaction of thiourea and DNA.The apparent intergreate constant calculated is 4.4×103 L/mol.The interaction mode between thiourea and ct-DNA were insetment and static,and the insetment is the mostly interaction mode.Forth,the thiaxanthon-2-yl-oxyacetate was synthesized,and the structure was characterized by elemental analysis,IR,1H NMR,and 13C NMR spectrum.We found from the experiment that thiaxanthon-2-yl-oxyacetate had very high fluorescence.Spectroscopy methods had been used in the interactions of thiaxanthon-2-yl-oxyacetate with ct-DNA.The ultraviolet absorption intensity of thiaxanthon-2-yl-oxyacetate decreased as the concentration of ct-DNA increased at pH=7.38.There were some debased intensity both in the negative and positive spectra of CD spectrum of ct-DNA when thiaxanthon-2-yl-oxyacetate interacted with ct-DNA,and quenching effect occurred in the fluorescence spectrum of thiaxanthon-2-yl-oxyacetate.The quenching constant is 1.25×104 L/mol,when the concentration of ct-DNA changed from 0～12.0 mg/L,the connection between the quenching data and the concentration of ct-DNA shows a favorable linear relationship. The detection limit was 1.63 mg/L,so the compound is a new reagent for the measurement of ct-DNA.The interaction between thiaxanthon-2-yl-oxyacetate and ct-DNA were insetment and static.
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