title: Effect of metal accumulation-associated oxidative stress on the combined toxicity of quantum dots with Cu(2+) to Bacillus subtilis.
abstract: Quantum dot (QD) nanoparticles can coexist with Cu(2+) in soil and can adsorb Cu(2+) entering into bacterial cells, thereby promoting cellular copper accumulation and enhancing the combined toxicity of these two chemicals. Toxicity test results on Bacillus subtilis showed that the addition of safe concentrations of MPA-CdTe QDs to Cu(2+) culture (levels under IC50 value) resulted in higher toxicity with about twofold reduction in cell viability and increased intracellular Cu content. ROS levels also increased by about 500%, and SOD activity was altered after QD addition. Treatment with Cu(2+) alone decreased the α-amylase activity of B. subtilis by 8%-35%. This finding was not affected by QD addition. Moreover, increased cellular copper concentration as a result of QD addition enhanced toxicity primarily by producing superoxide anions. However, this phenomenon did not interrupt the physical-biological responses of soil microbes.
authors.affiliation: School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, China; College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Chemical Engineering, Huaihai Institute of technology, Lianyungang 222000, China.
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: School of Chemical Engineering, Huaihai Institute of technology, Lianyungang 222000, China.
authors.forename: Ken
authors.initials: K
authors.lastname: Zhong
authors.affiliation: College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
authors.forename: Hejin
authors.initials: H
authors.lastname: Yao
authors.affiliation: School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, China. Electronic address: kflin@ecust.edu.cn.
authors.forename: Kuangfei
authors.initials: K
authors.lastname: Lin
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects* / Q000378:metabolism; D019187:Cadmium Compounds / Q000633:toxicity*; D003300:Copper / Q000494:pharmacology / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D045663:Quantum Dots / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013691:Tellurium / Q000633:toxicity*; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D019187:Cadmium Compounds; D017382:Reactive Oxygen Species; D003300:Copper; D013482:Superoxide Dismutase; D000516:alpha-Amylases; D013691:Tellurium; C028337:cadmium telluride
keywords: B. subtilis; Cu(2+); QDs; Ros