School of Environment, Beijing Normal University, 19 Xinjiekouwai Street, Beijing 100875, China.
School of Environment, Beijing Normal University, 19 Xinjiekouwai Street, Beijing 100875, China.
J Hazard Mater. 2024 Jul 15;473:134679. doi: 10.1016/j.jhazmat.2024.134679. Epub 2024 May 22.
The phycosphere is an essential ecological niche for the proliferation of antibiotic resistance genes (ARGs). However, how ARGs' potential hosts change and the driving mechanism of metabolites under antibiotic stress in the phycosphere have seldom been researched. We investigated the response of Chlorella pyrenoidosa and the structure and abundance of free-living (FL) and particle-attached (PA) bacteria, ARGs, and metabolites under sulfadiazine by using real-time quantitative PCR, 16 S rRNA high-throughput. The linkage of key bacterial communities, ARGs, and metabolites through correlations was established. Through analysis of physiological indicators, Chlorella pyrenoidosa displayed a pattern of "low-dose promotion and high-dose inhibition" under antibiotic stress. ARGs were enriched in the PA treatment groups by 117 %. At the phylum level, Proteobacteria, Bacteroidetes, and Actinobacteria as potential hosts for ARGs. At the genus level, potential hosts included Sphingopyxis, SM1A02, Aquimonas, Vitellibacter, and Proteiniphilum. Middle and high antibiotic concentrations induced the secretion of metabolites closely related to potential hosts by algae, such as phytosphingosine, Lysophosphatidylcholine, and α-Linolenic acid. Therefore, changes in bacterial communities indirectly influenced the distribution of ARGs through alterations in metabolic products. These findings offer essential details about the mechanisms behind the spread and proliferation of ARGs in the phycosphere.
藻际是抗生素耐药基因 (ARGs) 增殖的重要生态位。然而，藻际中抗生素胁迫下 ARGs 潜在宿主的变化及其代谢物的驱动机制还很少被研究。我们通过实时定量 PCR 和 16S rRNA 高通量技术，研究了磺胺嘧啶胁迫下，微囊藻和自由生活（FL）及颗粒附着（PA）细菌、ARGs 和代谢物的响应。通过相关性建立了关键细菌群落、ARGs 和代谢物之间的联系。通过分析生理指标，发现微囊藻在抗生素胁迫下表现出“低剂量促进和高剂量抑制”的模式。ARGs 在 PA 处理组中富集了 117%。在门水平上，变形菌门、拟杆菌门和放线菌门是 ARGs 的潜在宿主。在属水平上，潜在宿主包括鞘氨醇单胞菌属、SM1A02 属、Aquimonas 属、黄杆菌属和蛋白菌属。中高抗生素浓度通过藻类分泌与潜在宿主密切相关的代谢物，如植物鞘氨醇、溶血磷脂胆碱和α-亚麻酸。因此，细菌群落的变化通过代谢产物的改变间接影响 ARGs 的分布。这些发现为藻际中 ARGs 的传播和增殖机制提供了重要的细节。
