Comparison on the molecular response profiles between nano zinc oxide (ZnO) particles and free zinc ion using a genome-wide toxicogenomics approach.
Increasing production and applications of nano zinc oxide particles (nano-ZnO) enhances the probability of its exposure in occupational and environmental settings, but toxicity studies are still limited. Taking the free Zn ion (Zn(2+)) as a control, cytotoxicity of a commercially available nano-ZnO was assessed with a 6-h exposure in Escherichia coli (E. coli). The fitted dose-cytotoxicity curve for ZnCl2 was significantly sharper than that from nano-ZnO. Then, a genome-wide gene expression profile following exposure to nano-ZnO was conducted by use of a live cell reporter assay system with library of 1820 modified green fluorescent protein (GFP)-expressing promoter reporter vectors constructed from E. coli K12 strains, which resulted in 387 significantly altered genes in bacterial (p < 0.001). These altered genes were enriched into ten biological processing and two cell components (p < 0.05) terms through statistical hypergeometric testing, strongly suggesting that exposure to nano-ZnO would result a great disturbance on the functional gene product synthesis processing, such as translation, gene expression, RNA modification, and structural constituent of ribosome. The pattern of expression of 37 genes altered by nano-ZnO (fold change>2) was different from the profile following exposure to 6 mg/L of free zinc ion. The result indicates that these two Zn forms might cause toxicity to bacterial in different modes of action. Our results underscore the importance of understanding the adverse effects elicited by nano-ZnO after entering aquatic environment.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210089, China.
Guanyong
G
Su
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210089, China. zhangxw@nju.edu.cn.
Xiaowei
X
Zhang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210089, China.|Department of Biomedical Veterinary Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada.|Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloom, Hong Kong, SAR, China.
John P
JP
Giesy
Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
Javed
J
Musarrat
Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
Quaiser
Q
Saquib
Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
Abdulaziz A
AA
Alkhedhairy
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210089, China. yuhx@nju.edu.cn.
Hongxia
H
Yu
D004926:Escherichia coli / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000633:toxicity*; D043922:Toxicogenetics; D015032:Zinc / Q000633:toxicity*; D015034:Zinc Oxide / Q000633:toxicity*
D015032:Zinc; D015034:Zinc Oxide
Cytotoxicity; Gene expression; Gene set enrichment analysis; Nanoparticle; Pathways