Studies On The Interaction Between Carbaryl, Diethofencarb Carbofuran And DNA

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.