Association of specific gut microbiota with polyethylene microplastics caused gut dysbiosis and increased susceptibility to opportunistic pathogens in honeybees

The emergence of microplastics as contaminants has raised concerns regarding their potential toxicity. Recent studies on microplastic pollution caused by food packaging have drawn attention to its impact on health. However, despite being used extensively in food packaging, there is little knowledge about the toxicity of polyethylene microplastics (PE-MPs). Here, we studied the toxicity of PE-MPs on the model animal honeybees using different particle sizes (1 μm, 10 μm, 100 μm in diameter). Oral exposure to 100-μm PE-MPs resulted in elevated honeybee mortality and increased their susceptibility to pathogens. This is likely due to the mechanical disruption and gut microbial dysbiosis by PE-MPs. Snodgrassella, a core functional gut bacteria, was specifically enriched on the surface of PE-MPs, which perturbs the gut microbial communities in honeybees. Furthermore, the increased mortality in challenge trials with the opportunistic pathogen Hafnia alvei for PE-MPs pre-exposed honeybees revealed a potential health risk. These findings provide fresh insights into evaluating the potential hazards associated with PE-MPs.

Response characteristics of indigenous microbial community in polycyclic aromatic hydrocarbons (PAHs) contaminated aquifers under polyethylene microplastics stress: A microcosmic experimental study

To understand the response characteristics of indigenous microbial community in PAH-contaminated aquifers to the coexistence of microplastics. In this paper, we constructed a groundwater microecosystem using lithologic media collected from the field and subjected it to the stress of a polyethylene microplastics (PE-MPs) concentration gradient. By conducting adsorption experiments and 16S rRNA sequencing, we revealed the growth, structure, metabolism, and resistance mechanisms of the indigenous microbial community in the aquifer lithologic media exposed to varying levels of co-stress from PE-MPs and phenanthrene. Our findings suggest that the adsorption capacity of aquifer lithologic media for phenanthrene is significantly weaker than that of PE-MPs. Additionally, our observations indicated that small particle lithologic media had a greater adsorption capacity for phenanthrene than large particle lithologic media. The presence of PE-MPs was found to increase both the abundance and diversity of microbial communities, although the relationship was not linear with the content of PE-MPs. When exposed to the combined stress of PE-MPs and phenanthrene, the relative abundance of Proteobacteria decreased while that of Bacteroidetes increased. Several genera belonging to Proteobacteria (Aeromonas, Desulfovibrio, Klebsiella, Pantoea, and Microvirgula) and Bacteroidetes (Macellibacteroides and Bacteroides) occupied a central position in the microbial community interaction network and showed significant correlations with other genera. Furthermore, an increase in the proportion of genera capable of degrading various refractory organics was observed. The presence of PE-MPs increased the phenanthrene content in the aquifer lithologic media, thereby intensifying the inhibitory effect on indigenous microbial community in this environment. Despite an increase in the phenanthrene content of aquifer lithologic media due to the presence of PE-MPs, indigenous microbial community in this environment exhibited resistance to the combined inhibition of PE-MPs and phenanthrene through a series of resistance mechanisms. These mechanisms included strengthening the N-cycle process, enhancing metabolic capacity for phenanthrene, improving perception, response, and adaptation to changes in the external environment or intracellular state, modifying the transmembrane transport of the cell membrane to the substrate, and regulating life processes.