邻苯二甲酸酯对黑土胶体微界面中DNA的影响

Effects of Phthalates on DNA in Black Soil Colloid Microinterfaces

邻苯二甲酸酯(PAEs)作为增塑剂已在全球范围内普遍应用,尤其是在农业生产中由于地膜的大量使用导致其在土壤中不断累积,检出率逐年升高,对粮食安全、生态环境以及人类健康均造成了严重威胁。该研究通过荧光光谱、荧光猝灭以及质粒转化等试验研究了环境污染物PAEs对黑土胶体微界面中DNA结构及其水平转移的影响。结果表明:当不同浓度的邻苯二甲酸二乙酯(DEP)与邻苯二甲酸二丁酯(DBP)加入到EB-DNA荧光体系中时,DEP-EB-DNA与DBP-EB-DNA反应体系中的荧光强度均呈现降低的趋势,荧光强度与DEP、DBP的增加量呈负相关,且在浓度为4.5×10^(-4)mol/L时DEP与DBP的荧光抑制率达到最大,分别为50%与36%,DEP对荧光的抑制率显著高于DBP,说明DEP与DBP能够与DNA相互作用影响DNA结构且DEP的影响更为显著;KI对DEP-DNA与DBP-DNA体系进行猝灭时其猝灭常数Ksv值分别为7.947(R^(2)=0.9959)、11.03(R^(2)=0.9803),相比于对照组DEP的Ksv值10.27(R^(2)=0.9960)与DBP的Ksv值13.52(R^(2)=0.9806)均发生了明显的下降,说明DEP和DBP与DNA是通过嵌插作用相互结合;随着DEP和DBP浓度的增加,游离态与固定态的质粒转化率与转化子数均明显降低,且DEP的抑制作用更明显。研究表明,DEP和DBP能够以嵌插方式与DNA结合,改变DNA的结构,并抑制黑土胶体微界面中DNA的水平转移,为揭示环境污染物PAEs对黑土胶体微界面DNA遗传特征及基因转移机制的影响提供理论支持。

Phthalic acid esters(PAEs)have been widely used as plasticizers around the world,especially in agricultural production,due to the extensive use of plastic film,PAEs continue to accumulate in soil,and the detection rate is increasing year by year.PAEs pose a serious threat to food security,ecological environment and human health.In this study,the influence of environmental pollutants PAEs on the genetic characteristics of DNA and its gene transfer mechanism in the colloidal micro-interface of black soil were evaluated by fluorescence spectrum,fluorescence quenching test and plasmid transformation test.The result showed that when different concentrations of diethyl phthalate(DEP)and dibutyl phthalate(DBP)were added to the EB-DNA fluorescence system,the fluorescence intensity of DEP-EB-DNA and DBP-EB-DNA reaction systems all showed a decreasing trend,and the fluorescence intensity was negatively correlated with the increase of DEP and DBP.At the concentration of 4.5×10^(-4)mol/L,the fluorescence inhibition rates of DEP and DBP reached the maximum of 50%and 36%,respectively,and the fluorescence inhibition rate of DEP was significantly higher than that of DBP,which indicated that DEP and DBP could interact with DNA and affect DNA structure,the effect of DEP is more pronounced.Moreover,compared with DEP(10.27,R^(2)=0.9960)and DBP(13.52,R^(2)=0.9806),the quenching constant Ksvvalues of DEP-DNA(7.947,R^(2)=0.9959)and DBP-DNA(11.03,R^(2)=0.9803)were significantly decreased,this indicates that DEP and DBP bind to DNA through intercalation.Additionally,the conversion rate of free or fixed plasmids as well as the number of transformant in the colloidal micro-interface of black soil were decreased with the increase of DEP and DBP concentrations,and the inhibitory effect of DEP was more obvious.Therefore,DEP and DBP could bind to DNA in an intercalated manner to change the structure of DNA,as well as the horizontal transfer of DNA was inhibited in the colloidal micro-interface of black soil,in order to provide theoretical support for revealing the influence of environmental pollutants PAEs on the DNA genetic characteristics and gene transfer mechanism in the black soil colloidal micro-interface.