We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
The decrease in transformation frequency sunlight-induced dissolved organic matter inhibits eARG transformation in microplastic biofilms at a single-cell and community-wide level
AI summary Read the abstract
Microplastics floating in water often host bacterial films that can spread antibiotic resistance genes—but this study found some good news: natural organic matter in water, when exposed to sunlight, creates reactive molecules that damage bacteria and disrupt the process by which they pick up resistance genes from their environment. This suggests that sunlight and natural water chemistry may act as a built-in brake on antibiotic resistance spreading through microplastic pollution, which is relevant since these resistant bacteria can eventually make their way into water supplies, seafood, and ecosystems humans depend on.
Microplastic (MP) biofilms serve as hotspots for the dissemination of extracellular antibiotic resistance genes (eARGs) via natural transformation. Dissolved organic matter (DOM) is a ubiquitous photosensitizer in aquatic systems, yet its net effect on eARG transformation within MP biofilms remains unclear. This study shows that environmentally relevant DOM under simulated sunlight inhibited eARG transformation in MP biofilms at the single-species level. DOM (5-40 mg/L) reduced natural transformation frequency to 0.55-0.87 times under simulated sunlight. DOM photochemistry also markedly decreased bacterial density and extracellular polymeric substance (EPS) components in MP biofilms. Mechanistic investigations using quenching experiments demonstrated that reactive oxygen species (ROS) photochemically generated from DOM played a dominant role in mediating this inhibitory effect. DOM photochemistry downregulated the expression of transformation-related functional genes, thereby impairing cellular competence for eARGs uptake and integration. A consistent inhibitory trend was observed in a multi-species system derived from natural water communities. The transformants identified in MP biofilms belonged to 4 phyla and 48 genera, with Escherichia (phylum Proteobacteria) exhibiting absolute dominance (95.22%-98.47%). The decline in eARG transformation frequency in MP biofilms was mainly attributable to a reduction in transformant abundance. Neutral community modeling further suggested that DOM under light imposed substantial deterministic selection on transformant community assembly in MP biofilms. Collectively, these findings demonstrate that DOM photochemistry acts as an important environmental constraint on natural transformation-based eARG dissemination in sunlit MP biofilms.
More Papers Like This
Characteristics and mechanisms of dissolved organic matter leached by photodegradation of polyethylene microplastics: role of adsorbed antibiotics
AI summary Read the abstract
Researchers investigated how UV-driven photoaging of polyethylene microplastics and their interactions with the antibiotic ofloxacin affect the release of dissolved organic matter in water. They found that UV exposure significantly increased DOM release from pristine microplastics, while antibiotic-adsorbed microplastics initially released different molecular weight compounds before converging to similar patterns. The study reveals that aging microplastics and their co-contaminants create complex secondary pollution dynamics in aquatic environments.
Hydrophilic Fraction of Dissolved Organic Matter Largely Facilitated Microplastics Photoaging: Insights from Redox Properties and Reactive Oxygen Species
AI summary Read the abstract
This study investigated how dissolved organic matter in natural water affects the breakdown of microplastics by sunlight. The water-soluble fraction of organic matter was most effective at speeding up microplastic aging by generating reactive oxygen species that attack the plastic surface. This matters because faster breakdown of microplastics in the environment creates smaller, potentially more dangerous nanoplastic particles that can more easily enter living organisms.
Composition and photodegradation transformation of Dissolved Organic Matter from microplastics versus natural sources: impacts on copper (Cu) and tetracycline (TC) binding behaviors.
AI summary Read the abstract
Researchers compared photodegradation and pollutant-binding behavior of dissolved organic matter from HDPE and PLA microplastics versus natural leaf-litter sources, finding that microplastic-derived DOM loses aromaticity faster under UV and shows weaker copper and tetracycline binding after photodegradation, potentially increasing free antibiotic concentrations and antibiotic-resistance risks in contaminated waters.
UVA Induced Photoaging of Microplastics Enhances Antibiotic Resistance Gene Enrichment in Sewage Biofilms
AI summary Read the abstract
Scientists found that when sunlight breaks down plastic from disposable cups (like the lining in paper coffee cups) in sewage water, bacteria stick to the damaged plastic more easily and are more likely to trade genes that make them resistant to antibiotics. This matters because it suggests sun-damaged microplastics in wastewater could act as breeding grounds that help "superbugs" develop and spread, potentially making infections harder to treat down the line.
Roles of microplastic-derived dissolved organic matter on the photodegradation of organic micropollutants
AI summary Read the abstract
Researchers discovered that dissolved organic matter released from weathered microplastics significantly inhibits the photodegradation of the antibiotic sulfamethoxazole in water, primarily through light screening effects, suggesting microplastic pollution may slow the natural breakdown of pharmaceutical contaminants.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.