【作者】 张立金；

【导师】 闵顺耕； 孙英；

【作者基本信息】 中国农业大学 ， 农药学， 2004， 硕士

【摘要】 农药化合物一般都对生物体具有生物效应。作为药物分子的靶标之一，DNA与药物分子的作用可能会引起遗传信息的改变。所以研究环境中的农药残留对DNA的作用机理具有重要的意义。 本文利用荧光以及紫外光谱的方法研究了三种农药甲萘威、乙霉威以及克百威与小牛胸腺DNA的作用机理，结果表明： 1、实验条件，包括溶液PH，溶液温度，反应时间，溶液极性以及溶液浓度等对药物与小牛胸腺DNA作用具有影响。 2、不同温度下的猝灭常数说明小牛胸腺DNA对药物分子的荧光光谱存在静态猝灭；荧光光谱、紫外光谱的偏移，K₄[Fe（CN）₆]的猝灭作用显示药物分子可以嵌入小牛胸腺DNA双链；热力学的计算确认小牛胸腺DNA的碱基与药物分子之间存在范德华作用；溶液极性改变小牛胸腺DNA的空间结构而影响其与药物分子的作用；离子强度不会改变两者的作用强度。 3、药物活性与小牛胸腺DNA对药物的猝灭常数存在对应关系；药物生物活性是其亲疏水性、平面结构面积、取代基种类、取代基的亲给电性、取代基位置、空间结构底等综合作用的结果。 4、在药物分子、小牛胸腺DNA与溴乙锭共存体系中，后两者对于药物分子都存在荧光猝灭效应；溶液极性以及离子强度可以改变小牛胸腺DNA的空间结构而减少药物与溴乙锭在小牛胸腺DNA上的结合位点。 5、甲萘威与小牛胸腺DNA之间的猝灭具有良好的线性关系，所以甲萘威可以用于荧光探针而对脱氧核糖核酸进行定量分析。更多还原

【Abstract】 It is well known that pesticides often have biological effects . As one of possible targets, DNA can be attacked by the molecules of pesticides, which may bring genetic information some changes .So it is important to study the mechanism of their interteractions.The interaction modes between calf thymus DNA and carbaryl, diethofencarb , carbofuran are studied by fluorescence and UV spectra .The results show that:1. The reaction conditions, including concentration of pesticides, PH of solution, temperature of solution, reactive times, polarity of solvent and ionic intensity of solution, all have effects on the interactions between pesticides and calf thymus DNA.2. The quenching constants at different temperatures are well concluded that calf thymus DNA lead to the static and fluorescent quenching of pesticides; both the shifts of their fluorescence and UV spectra and the quenching of K4tFe (CN)6] indicate that the molecules of the pesticides intercalate into the twin-screw’s structure of calf thymus DNA; the thermodynamic calculating demonstrates that there exists VanderWaals Force between the molecules of pesticides and calf thymus DNA. Additional, the polarity of solvent affect the interactions by changing the structure of calf thymus DNA , but ionic intensity does not change the interactions.3, The bioactivities of pesticides are directly proportional to quenching constants. Bioactivities of pesticides come out as the results of hydrophilic properties, areas of planar structures, varieties of substituted proups, electrophilic property of substituted proups, position of substituted proups, and spatial structures.4, Considering the system among pesticides, ct DNA and ethidium bromide, the latter two compounds can both lead to the fluorescent quchening of pesticides. By means of changing the spatial structure of calf thymus DNA, the polarity of solvent and ionic intensity of solution decrease the number of positions that pesticides and ethidium bromide can bind to.5 Owing to the linear relation of the quenching between carbaryl and ct DNA, carbaryl is regarded as one kind of fluorescent probe to detect DNA.更多还原