title: Regulation of membrane fixation and energy production/conversion for adaptation and recovery of ZnO nanoparticle impacted Nitrosomonas europaea.
abstract: 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.
authors.affiliation: 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.
authors.forename: Junkang
authors.initials: J
authors.lastname: Wu
authors.affiliation: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Huijie
authors.initials: H
authors.lastname: Lu
authors.affiliation: 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.
authors.forename: Guangcan
authors.initials: G
authors.lastname: Zhu
authors.affiliation: 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.
authors.forename: Lianghui
authors.initials: L
authors.lastname: Chen
authors.affiliation: 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.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chang
authors.affiliation: 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. yuran@seu.edu.cn.|Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China. yuran@seu.edu.cn.
authors.forename: Ran
authors.initials: R
authors.lastname: Yu
mesh_terms: D000064:Acclimatization; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000641:Ammonia / Q000378:metabolism; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D004734:Energy Metabolism; D015964:Gene Expression Regulation, Bacterial; D006019:Glycolysis; D053858:Metabolic Networks and Pathways / Q000235:genetics; D046228:Microarray Analysis; D053758:Nanoparticles; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D043370:Nitrosomonas europaea / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D015034:Zinc Oxide / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D009573:Nitrites; D002244:Carbon; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase; D009584:Nitrogen; D010100:Oxygen; D015034:Zinc Oxide
keywords: Inhibition; Microarray; Nitrosomonas europaea; Recovery; ZnO nanoparticle