The Study Of DNA-target Molecules And Hg～(2+) Biosensors

As a novel family of DNA-target molecules, 8-Oxo-8H-acenaphtho[l,2-b]pyrrole-9-carbonitrile and its derivatives (A1-A5), their interaction with DNA and antitumor abilities are evaluated by agarose gel electrophoresis, fluorescence spectrum, DNA melt curves, cytotoxicity experience. The results indicate that the compound A1 with a diethyl-amine group can bind to DNA through electrostatic attractions and intercalation and then generate singlet oxygen to cleave M13 mp18 single strand circular DNA under the irradiation of long wavelength light (λ>400 nm), the lowest effective concentration is 50 μM, its DNA binding constant is 2.62×106M-1 which is 10-100 times more than A2-A5. The comparison of A1-A5 also shows that the basic side chain indeed can promote biological abilities of compound. MTT (Thiazolyl Blue) test against HELA cell furthermore proves that IC50 of Al is 6.8 μM, which is the higher anticancer activity. Especially, the absorption wavelength of Al is 570nm, which makes Al be a valuable leading compound for the safe antitumor photodynamic therapeutic agents with long wavelength.Two original Hg2+ fluorescence sensors, HPNP and EPNP, are developed to apply on cell biology. By laser scarring confocal microscope, the study of mercuric ion in single living cell of mammalian and plant is high selectively, quantificationally and visibly achieved for the first time. Under the acute stress of low concentration Hg2+, in human kidney proximal tubular epithelial cell, Hg2+ mainly locates perinuclear and on nuclear membrane; in transgenic tobacco cell, Hg2+ accumulates on chloroplast. By comparing the biological results of the two fluorescence sensors having similar chemical structures, the relation between compound property and its action in biological system is summarized: HPNP is suitable to rapidly reflect the permeability rate of Hg2+ inside cell since it is more hydrophilic, while the proper amphipathy of EPNP makes its background fluorescence low and imaging clear, which is more suitable for researching location of intracellular Hg2+.