Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Southeast University, No. 2 Sipailou Street, Nanjing, Jiangsu, 210096, China.
Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China.
Appl Microbiol Biotechnol. 2017 Apr;101(7):2953-2965. doi: 10.1007/s00253-017-8092-0. Epub 2017 Jan 10.
The ZnO nanoparticle (NP) effects on typical ammonia-oxidizing bacteria, Nitrosomonas europaea in a chemostat bioreactor, and the cells' toxicity adaptation and recovery potentials were explored. Hardly any inhibition was observed when the NP concentration was high up to 10 mg/L. The cells exposed to 50 mg/L ZnO NPs displayed time-dependent impairment and recovery potentials in terms of cell density, membrane integrity, nitrite production rate, and ammonia monooxygenase activity. The 6-h NP stress impaired cells were nearly completely restored during a 12-h recovery incubation, while the longer exposure time would cause irretrievable cell damage. Microarray analysis further indicated the transcriptional adaptation of N. europaea to NP stress. The regulations of genes encoding for membrane permeability or osmoprotectant, membrane integrity preservation, and inorganic ion transport during NP exposure and cell recovery revealed the importance of membrane fixation and the associated metabolisms for cells' self-protection and the following recovery from NP stress. The oxidative phosphorylation, carbon assimilation, and tricarboxylic acid (TCA) cycling pathways involved in the cells' antitoxicity activities and would promote the energy production/conversion efficiency for cell recovery. The heavy metal resistance, histidine metabolism, toxin-antitoxin defense, glycolysis, and sulfate reduction pathways were also suggested to participate in the cell detoxication and recovery processes. All these findings provided valuable insights into the mechanisms of cell-mediated ZnO NP cytotoxicity and their potential impacts on wastewater nitrogen removal system.
采用连续流搅拌槽式生物反应器，研究了氧化锌纳米颗粒（NP）对典型氨氧化细菌（Nitrosomonas europaea）的影响，以及细胞的毒性适应和恢复潜力。当 NP 浓度高达 10mg/L 时，几乎没有观察到抑制作用。当细胞暴露于 50mg/L ZnO NPs 时，细胞密度、膜完整性、亚硝酸盐生成速率和氨单加氧酶活性表现出时间依赖性损伤和恢复潜力。在 12 小时的恢复孵育过程中，6 小时 NP 胁迫损伤的细胞几乎完全恢复，但较长的暴露时间会导致不可逆转的细胞损伤。微阵列分析进一步表明，N. europaea 对 NP 胁迫的转录适应。在 NP 暴露和细胞恢复过程中，编码膜通透性或渗透保护剂、膜完整性维持和无机离子转运的基因的调控，揭示了膜固定及其相关代谢对细胞自我保护和随后从 NP 胁迫中恢复的重要性。参与细胞抗毒性活性的氧化磷酸化、碳同化和三羧酸（TCA）循环途径，将促进细胞恢复的能量产生/转换效率。重金属抗性、组氨酸代谢、毒素-抗毒素防御、糖酵解和硫酸盐还原途径也被认为参与了细胞解毒和恢复过程。这些发现为细胞介导的 ZnO NP 细胞毒性的机制及其对废水脱氮系统的潜在影响提供了有价值的见解。
