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Updated: Jun 4, 2026
05:31
Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris
Published on: July 28, 2018
The decrease in transformation frequency sunlight-induced dissolved organic matter inhibits eARG transformation in
Xiaowei Liu1, Qingjie Yang1, Yiwei Dong1
1School of Life and Health Sciences, Environmental Engineering, Hefei University, Hefei, 230601, China.
Journal of Environmental Management
|June 2, 2026
Summary
Dissolved organic matter (DOM) under sunlight inhibits antibiotic resistance gene spread on microplastic biofilms. DOM photochemistry reduces gene transformation by decreasing bacterial numbers and impairing gene uptake.
Area of Science:
- Environmental microbiology
- Aquatic chemistry
- Antimicrobial resistance
Background:
- Microplastic (MP) biofilms facilitate the spread of extracellular antibiotic resistance genes (eARGs) through natural transformation.
- The impact of dissolved organic matter (DOM), a common photosensitizer in aquatic environments, on this process is not well understood.
Purpose of the Study:
- To investigate the effect of DOM photochemistry on eARG transformation within MP biofilms.
- To elucidate the mechanisms underlying DOM's influence on eARG dissemination.
Main Methods:
- Experiments were conducted using single-species and multi-species MP biofilms under simulated sunlight.
- DOM concentrations ranged from 5-40 mg/L.
- Quenching experiments and gene expression analysis were used to identify the role of reactive oxygen species (ROS) and transformation-related genes.
Main Results:
- DOM significantly inhibited eARG transformation frequency (0.55-0.87 times) under simulated sunlight.
- DOM photochemistry reduced bacterial density and extracellular polymeric substance (EPS) components.
- Reactive oxygen species (ROS) generated from DOM were identified as the primary mediators of inhibition, downregulating transformation-related genes and impairing cellular competence.
- A consistent inhibitory trend was observed in multi-species biofilms, with Escherichia dominating transformants.
- Neutral community modeling indicated deterministic selection by DOM under light on transformant community assembly.
Conclusions:
- DOM photochemistry acts as a significant environmental factor limiting the spread of eARGs via natural transformation in sunlit MP biofilms.
- This inhibition is primarily mediated by ROS and affects bacterial density, EPS, and the expression of key genetic pathways for transformation.
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