A plasmid DMA assay was used to investigate the bioreactivity of PM2,5 and PM10 and the oxidative capacity of mental elements in the particles in urban, suburban and clean areas of Harbin city, northeastern China. The results show that the water-soluble fraction and intact whole sample solutions of PM samples have obvious bioreactivity, and their TD40 values are 67.9-1 570 )礸/mL, suggesting that the oxidative capacity of particles is related to sources and natures of particles. The main elements damaging plasmid DNA are transitional metals, with certain amounts of alkali metals and other main group elements. In addition to transitional metals, the rare earth elements in particles play a major role in the DNA damage. The TD40 value of the water-soluble fraction of the PM samples present a positive correlation with the concentration of Y and a negative correlation with La, Lu, Ho and Sm. This indicates that during the exposure of water-soluble fraction to plasmid DNA, the elements La, Lu, Ho and Sm are cooperated to cause damage to the plasmid, while Y helps to antagonise this damage. The TD40 value of the whole intact PM sample shows a positive correlationrnwith the concentration (礸/g PM) of Cs, La, Mn, Pb, Tm and Gd, and a negative correlation with Tb, Ni, Yb, Er, W, Cd and In. This demonstrates that during the exposure of the whole intact sample solution to plasmid DNA, the elements Tb, Ni, Yb, Er, W, Cd and In are combined to cause damage to the plasmid, while the elements Cs, La, Mn, Pb, Tm and Gd help to antagonise this damage.%采用质粒DNA评价法评价哈尔滨市市区、郊区和清洁对照点的PM10和PM2.5样品的生物活性及颗粒物中金属元素对质粒DNA的氧化性损伤能力.研究结果表明,水溶样和全样样品都具有一定的活性,样品的TD40值为67.9～1 570 μg/mL,说明PM的生物活性主要与其来源和性质有关;颗粒物中具有生物活性的元素主要为过渡金属,其次为碱金属或其他主族元素,除过渡金属外,稀土元素对颗粒物的生物活性也具有显著影响.水溶样的TD40值与Y的浓度呈正相关,与La,Lu,Ho,Sm的浓度呈负相关,说明在对质粒DNA损伤过程中,Y拮抗La,Lu,Ho,Sm的损伤作用;全样的TD40值与元素Cs,La,Mn,Pb,Tm,Gd的浓度呈正相关,与Tb,Ni,Yb,Er,W,Cd,In的浓度呈负相关,在对质粒DNA损伤过程中,元素Cs,La,Mn,Pb,Tm,Gd协同拮抗Tb,Ni,Yb,Er,W,Cd,In的损伤作用.
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