Zhang Chenxi, Geng Mengke, Zhang Gongxu, Ye Nan, Wang Yue, Zhang Shuai
Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CIC-AEET), School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
School of Environmental Science and Engineering, Tiangong University, Tianjin, 300387, China.
J Environ Manage. 2025 Aug 20;393:127013. doi: 10.1016/j.jenvman.2025.127013.
Heavy metals can accelerate the dissemination of antibiotic resistance genes (ARGs) in aquatic environments by imposing environmental stresses. Signaling molecules play a role in bacterial communication and help bacteria adapt to environmental stresses. However, little is known whether the presence of signaling molecules has an effect on the spread of ARGs induced by heavy metals. In this study, we investigated how N-decanoyl-L-homoserine lactone (C10-HSL) affects copper-induced conjugative transfer of ARGs. We calculated the conjugative transfer frequency and measured reactive oxygen species (ROS) production, membrane permeability, and the expression of relevant genes. The results demonstrated that the addition of C10-HSL increased the conjugative transfer frequency of ARGs under copper ions (Cu) stress, showing a 7.2-fold increase under 0.5 μM Cu and 0.39 μM C10-HSL treatment compared to the control. This enhancement was associated with elevated intracellular ROS production and increased membrane permeability. The reduced conjugative transfer frequency under anaerobic conditions or with thiourea treatment supported the key role of ROS in this process. Furthermore, ROS overproduction triggered the SOS response, as evidenced by a 9-fold upregulation of recA expression. C10-HSL also modulated membrane-associated gene expression by upregulating outer membrane porins and downregulating efflux pump genes under Custress. This study provides a new insight into the spread of ARGs in aquatic environments.
重金属可通过施加环境压力加速抗生素抗性基因（ARGs）在水生环境中的传播。信号分子在细菌通讯中发挥作用，并帮助细菌适应环境压力。然而，关于信号分子的存在是否会对重金属诱导的ARGs传播产生影响，目前知之甚少。在本研究中，我们调查了N-癸酰基-L-高丝氨酸内酯（C10-HSL）如何影响铜诱导的ARGs接合转移。我们计算了接合转移频率，并测量了活性氧（ROS）的产生、膜通透性和相关基因的表达。结果表明，添加C10-HSL会增加铜离子（Cu）胁迫下ARGs的接合转移频率，在0.5 μM Cu和0.39 μM C10-HSL处理下，与对照相比增加了7.2倍。这种增强与细胞内ROS产生增加和膜通透性增加有关。厌氧条件下或用硫脲处理后接合转移频率降低，支持了ROS在这一过程中的关键作用。此外，ROS的过量产生触发了SOS反应，recA表达上调9倍证明了这一点。C10-HSL还通过在铜胁迫下上调外膜孔蛋白和下调外排泵基因来调节膜相关基因的表达。本研究为水生环境中ARGs的传播提供了新的见解。
