Related Experiment Video
Updated: Jul 26, 2026
Air-sampled Filter Analysis for Endotoxins and DNA Content
Published on: March 7, 2016
Bioreactivity of particulate matter in Beijing air: results from plasmid DNA assay
Longyi Shao1, Zongbo Shi, T P Jones
1Key Laboratory of Coal Resources of Chinese Ministry of Education and the Department of Resources and Earth Sciences, China University of Mining and Technology, D11, Xueyuan Road, Beijing, 100083, PR China. shaoL@cumtb.edu.cn
Abstract:
An in vitro plasmid assay was employed to study the bioreactivity of PM (particulate matter) in Beijing air. It was found that the TD20 (toxic dose of PM causing 20% of plasmid DNA damage) of Beijing PM can be as low as 28 microg ml(-1) and as high as >1000 microg ml(-1). Comparison of the physical properties, such as morphology and size distribution, and oxidative potential indicates that the PM(2.5) (particulate matter with an aerodynamic diameter of 2.5 microm or less) has a stronger oxidative capacity than PM(10) (particulate matter with an aerodynamic diameter of 10 microm or less), and that the higher number percentages of soot aggregates and lower number percentages of mineral and fly ashes are associated with the higher oxidative capacity. Although the mass of PM(10) during dust storms is commonly 5 times higher than that during non-dust storm episodes, the oxidative capacity of PM(10)s of dust storms is much lower than that of the non-dust storm PM(10)s. The water-soluble fractions and intact whole particle solutions of Beijing airborne particles produce similar plasmid assay results, demonstrating that the bioreactivity of Beijing airborne particles is mainly sourced from the water-soluble fraction. In the samples with stronger bioreactivity, the total analyzed water soluble Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Pb (ppm) concentrations are higher. The water soluble zinc shows a good negative correlation with TD20s, suggesting that the water-soluble zinc is probably the major element responsible for the plasmid DNA damage.
Insights
Beijing particulate matter (PM) exhibits variable toxicity, with PM(2.5) showing higher oxidative capacity. Water-soluble fractions, particularly zinc, are identified as the primary drivers of PM-induced DNA damage.
Area of Science:
- Environmental Science
- Toxicology
- Air Quality Research
Background:
- Particulate matter (PM) in urban air poses significant health risks.
- Understanding the bioreactivity and toxicological mechanisms of PM is crucial for public health.
- Beijing's air quality is a major concern, necessitating detailed studies on PM composition and effects.
Purpose of the Study:
- To investigate the in vitro bioreactivity of Beijing's airborne particulate matter using a plasmid DNA assay.
- To identify the physical and chemical properties of PM associated with its DNA damaging potential.
- To determine the specific components within PM responsible for its observed bioreactivity.
Main Methods:
- Utilized an in vitro plasmid assay to assess DNA damage induced by Beijing PM.
- Analyzed physical properties including morphology and size distribution (PM(2.5) vs. PM(10)).
- Quantified oxidative potential and measured concentrations of water-soluble metals (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Pb).
Main Results:
- Beijing PM demonstrated a wide range of toxic doses (TD20) for plasmid DNA damage (28 to >1000 microg ml(-1)).
- PM(2.5) exhibited stronger oxidative capacity than PM(10), linked to soot aggregates.
- Bioreactivity was primarily attributed to water-soluble fractions, with higher concentrations of various metals correlating with increased damage. Water-soluble zinc showed a strong negative correlation with TD20.
Conclusions:
- The bioreactivity of Beijing airborne particles is mainly derived from their water-soluble components.
- Water-soluble zinc is identified as a key element responsible for PM-induced plasmid DNA damage.
- Oxidative potential varies with PM characteristics, with PM(2.5) and non-dust storm PM(10) being more potent than dust storm PM(10).
