Centre for Agriculture and Health, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China.
Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
J Hazard Mater. 2024 Aug 15;475:134884. doi: 10.1016/j.jhazmat.2024.134884. Epub 2024 Jun 12.
Nanoplastics (NPs), identified as emerging pollutants, pose a great risk to environment and global public health, exerting profound influences on the prevalence and dissemination of antibiotic resistance genes (ARGs). Despite evidence suggesting that nano-sized plastic particles can facilitate the horizontal gene transfer (HGT) of ARGs, it is imperative to explore strategies for inhibiting the transfer of ARGs. Currently, limited information exists regarding the characteristics of environmentally aged NPs and their impact on ARGs propagation. Herein, we investigated the impact of photo-aged NPs on the transfer of ARG-carrying plasmids into Escherichia coli (E. coli) cells. Following simulated sunlight irradiation, photo-aged nano-sized polystyrene plastics (PS NPs) exhibited multiple enzyme-like activities, including peroxidase (POD) and oxidase (OXD), leading to a burst of reactive oxygen species (ROS). At relatively low concentrations (0.1, 1 μg/mL), both pristine and aged PS NPs facilitated the transfer of pUC19 and pHSG396 plasmids within E. coli due to moderate ROS production and enhanced cell membrane permeability. Intriguingly, at relatively high concentrations (5, 10 μg/mL), aged PS NPs significantly suppressed plasmids transformation. The non-unidirectional impact of aged PS NPs involved the overproduction of ROS (•OH and •O) via nanozyme activity, directly degrading ARGs and damaging plasmid structure. Additionally, oxidative damage to bacteria resulted from the presence of much toxic free radicals, causing physical damage to cell membranes, reduction of the SOS response and restriction of adenosine-triphosphate (ATP) supply, ultimately leading to inactivation of recipient cells. This study unveils the intrinsic multienzyme-like activity of environmentally aged NPs, highlighting their potential to impede the transfer and dissemination of ARGs.
纳米塑料（NPs）作为新兴污染物，对环境和全球公共健康构成了巨大威胁，对抗生素耐药基因（ARGs）的流行和传播产生了深远影响。尽管有证据表明纳米级塑料颗粒可以促进 ARGs 的水平基因转移（HGT），但探索抑制 ARGs 转移的策略至关重要。目前，关于环境老化 NPs 的特性及其对 ARGs 传播的影响的信息有限。在此，我们研究了光老化 NPs 对携带 ARG 质粒向大肠杆菌（E. coli）细胞转移的影响。在模拟阳光照射后，光老化的纳米级聚苯乙烯塑料（PS NPs）表现出多种酶样活性，包括过氧化物酶（POD）和氧化酶（OXD），导致活性氧（ROS）的爆发。在相对较低的浓度（0.1、1μg/mL）下，由于适度的 ROS 产生和增强的细胞膜通透性，原始和老化的 PS NPs 都促进了 pUC19 和 pHSG396 质粒在 E. coli 中的转移。有趣的是，在相对较高的浓度（5、10μg/mL）下，老化的 PS NPs 显著抑制了质粒的转化。老化 PS NPs 的非单向影响涉及通过纳米酶活性过度产生 ROS（•OH 和•O），直接降解 ARGs 并破坏质粒结构。此外，由于存在大量有毒自由基，细菌受到氧化损伤，导致细胞膜物理损伤、SOS 反应减少和腺嘌呤三磷酸（ATP）供应受限，最终导致受体细胞失活。本研究揭示了环境老化 NPs 的固有多酶样活性，强调了它们抑制 ARGs 转移和传播的潜力。
