Interaction of DNA with aromatic hydrocarbons fraction in atmospheric particulates of Xigu District of Lanzhou,China

Voluminously epidemiological studies show that the relationships exist between the air pollution and human health and cancer. Aromatic hydrocarbons （AHs） in air form a large class of organic pollutants, which are widely in environment and many of them are known to be carcinogenic and/or mutagenic and contribute to ambient air pollution. In the past decades, bioassays mainly have been used to evaluate the toxicity of chemical mixtures in atmospheric particulates or aqueous environment. However, it is well known that the covalent complexes formed by carcinogens with DNA may be exert negative results in bioassay. So the main aim of this paper is to develop an evaluation method of toxicity effects of chemical mixtures in atmospheric particulates from chemical standpoint. In this study, the in vitro interaction of the AHs with DNA was investigated by absorption, fluorescence and resonance light scattering （RLS） spectroscopic techniques. The results showed that the AHs in the atmospheric particulates could combine with calf thymus DNA （ctDNA） and herring sperm DNA （hsDNA） without being activated or metabolized by organism, respectively. Intercalation may be present in the mechanism of interaction. The binding constants of the AHs with ctDNA and hsDNA were 2.5x102 and 2.0x103, respectively, which indicated that the interaction of the AHs with hsDNA is stronger than that with ctDNA. In addition, the relationships of dose-effect between the total mole concentration of chemical components and the ability of binding ctDNA and hsDNA were confirmed. This research made it possible to study the toxicity effects of chemical mixtures in atmospheric particulates by chemical method. It is believed that the composition and contents of unknown AHs and the interaction of DNA with AHs in atmospheric particulates of Xigu District of Lanzhou City, China are first reported in the past twenty years.

Synthesis,crystal structures of novel complexes of rare earth with norfloxacin,interaction with DNA and BSA

Three novel rare earth complexes [N（CH 3） 4 ][Ln（NF） 4 ]·6H 2 O（Ln=Nd（III）（1）,Sm（III）（2）,Ho（III）（3）） were synthesized using hydrothermal method from norfloxacin HNF=1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-（1-piperazinyl）-3-quinoline carboxylic acid,C 16 H 18 FN 3 O 3）,imidazole and rare earth nitrates.The complexes were characterized by elemental analysis,FT-IR,TG-DTG and X-ray single crystal diffraction.Each rare earth ion was eight-coordinated with carboxyl-O atoms and keto-O atoms from norfloxacin.Four of the norfloxacin ions acted as bidentate chelate group took part in the coordination with rare earth ion.The structures of complexes were tetragonal system with space group I4 1 /acd,which were allomerism.The interaction between complex 1 and DNA was studied by electronic absorption spectra and fluorescence spectroscopy.The binding interaction between the complex 1 and bovine serum albumin（BSA） was studied by fluorescence spectroscopy.The complex 1 bound to DNA by the mode of partial intercalation.Complex 1 had a strong ability to quench the fluorescence from BSA.The complex interaction was mainly a static quenching process with BSA together with formation of two binding sites.

Synthesis,Crystal Structure and Bioactivity of a Pd(Ⅱ) Complex with Demethylcantharate and 2,2′-Bipyridine

A novel crystal with the molecular formula [Pd（DCA）（bipy）]2 [Pd（bipy）Cl2 ]·6.75H2O was formed by PdCl2 with disodium demethylcantharate （Na2 （DCA）,DCA2= 7-oxa-bicyclo[2.2.1]heptane-2,3-bicarboxylate） and 2,2-bipyidine （bipy） through the hydrothermal method.The complex was characterized by elemental analysis and infrared spectroscopy.The structure of the complex was determined by single-crystal X-ray diffraction,which is of triclinic system,space group P1 with a=13.6818（7）,b=14.8426（8）,c=15.0043（8）,α=97.319（3）,β=92.521（3）,γ=105.776（2）°,V=2898.4（3） 3,Dc=1.545 g·cm-3,Z=1,F（000）=1420,S=0.852,the final R=0.0525 and wR=0.1777 for 13634 observer reflections （I〉2σ（I））.The binding reaction of the complex with ct-DNA and bovine serum albumin （BSA） was studied by fluorescence spectroscopy.The results indicated that the complex binds to ct-DNA via the partial intercalation.The binding constant K A of the complex interaction with BSA was 3.98×10 5 L·mol-1 and one binding site would be formed.The antiproliferative activity of the complex against human hepatoma cells （SMMC7721） in vitro is much higher than that of Na 2 （DCA）.