Dali Wang,Yuheng Zhong,Qi Ding,Xiaofeng Han,Kai Chen,Bo Pan,Jing You
Nanoplastics (NPs) and antibiotics are emerging contaminants that co-occur ubiquitously in coastal environments and pose risks to ecosystems. Here, we report the single and combined effects of nano-sized polystyrene (PS) and erythromycin on a marine benthic invertebrate N. succinea at both individual and intestinal microbial levels. It was found that PS at 10 and 1000 μg L−1 and erythromycin at 249 and 7170 ng L−1, individually and in combination, did not cause mortality of N. succinea, but altered organism weight and behaviors and led to morphological changes and oxidative stresses in the intestines. Synergistic effects on glutathione-S-transferase activity and burrowing behavior were observed for mixtures containing high levels of PS. The results of 16S rRNA sequencing showed that erythromycin at both concentrations did not cause changes in microbial composition at the phylum level, while PS and the mixtures significantly increased the relative abundance of Proteobacteria, and reduced Actinobacteriota, Bacteroidota and Firmicutes. At the genus level, erythromycin decreased some potential pathogens such as Vibrio, Nautella, and Pseudomonas, whereas PS and the mixtures reduced beneficial genera such as Megasphaera and Megamonas. Community-level physiological profiles showed that erythromycin and PS had distinct influences on the metabolism of the cultivable intestinal microbiota, with erythromycin enhancing while PS and the mixtures inhibiting the metabolic capacity and diversity. Collectively, our results illustrated that PS NPs and erythromycin exerted distinct influences on the intestinal microbiota of N. succinea, and their mixture effects were dominated by the PS effect.
Dali Wang,Qi Ding,Yuheng Zhong,Xiaofeng Han,Long Fu,Jing Yu,Kunting Li,Jing You
The exposure of aquatic organisms to pollutants often occurs concomitantly with salinity fluctuations. Here, we reported the effects of erythromycin (0.250, 7.21, and 1030 μg/L) on marine invertebrate N. succinea and its intestinal microbiome under varying salinity levels (5‰, 15‰, and 30‰). The salinity elicited significant effects on the growth and intestinal microbiome of N. succinea. The susceptibility of the intestinal microbiome to erythromycin increased by 8.7- and 6.2-fold at salinities of 15‰ and 30‰, respectively, compared with that at 5‰ salinity. Erythromycin caused oxidative stress and histological changes in N. succinea intestines, and inhibited N. succinea growth in a concentration-dependent manner under 30‰ salinity with a maximum inhibition of 25%. At the intestinal microbial level, erythromycin enhanced the total cell counts at 5‰ salinity but reduced them at 15‰ salinity. Under all tested salinities, erythromycin diminished the antibiotic susceptibility of the intestinal microbiome. Two-way ANOVA revealed significant interactive effects (p < 0.05) between salinity and erythromycin on various parameters, including antibiotic susceptibility and intestinal microbial diversity. The present findings demonstrated the significant role of salinity in modulating the impacts of erythromycin, emphasizing the necessity to incorporate salinity fluctuations into environmental risk assessments.
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