title: Metabolic responses of the growing Daphnia similis to chronic AgNPs exposure as revealed by GC-Q-TOF/MS and LC-Q-TOF/MS.
abstract: Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials. Their fast-growing utilization has increased the occurrence of AgNPs in the environment, posing potential health and ecological risks. In this study, we conducted chronic toxicity tests and investigated the metabolic changes of the growing Daphna similis with exposure to 0, 0.02, and 1 ppb AgNPs, using non-targeted mass spectrometry-based metabolomics. To the best of our knowledge, this study is the first to report the baseline metabolite change of a common aquatic organism Daphnia crustacean through its life-cycle. The results show a dynamic kinetic pattern of the growing Daphnia's metabolome underwent a cycle from day 0 to day 21, with the level of metabolites gradually increasing from day 0 to day 13, before falling back to the baseline level of day 0 on day 21. As for the samples exposed to environmental concentrations of AgNPs, although without morphological or structural changes, numerous metabolite changes occurred abruptly during the first 10 days, and these changes reached steady state by day 13. The significant changes in certain metabolites, such as amino acids (serine, threonine and tyrosine), sugars (d-allose) and fatty acids (arachidonic acid) revealed new insights into how these metabolites in Daphnia respond to chronic AgNPs stress. These findings highlight the capability of metabolomics to discover early metabolic responses to environmental silver nanoparticles.
authors.affiliation: School of Environmental Science & Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: NUS Environmental Research Institute, National University of Singapore, Singapore, 117411, Singapore.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: School of Environmental Science & Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Du
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
authors.forename: Qin Xiang
authors.initials: QX
authors.lastname: Ng
authors.affiliation: Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minghan District, Shanghai 200240, China.
authors.forename: Chaoyang
authors.initials: C
authors.lastname: Hu
authors.affiliation: School of Environmental Science & Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China. Electronic address: ylhe@sjtu.edu.cn.
authors.forename: Yiliang
authors.initials: Y
authors.lastname: He
authors.affiliation: NUS Environmental Research Institute, National University of Singapore, Singapore, 117411, Singapore. Electronic address: eridir@nus.edu.sg.
authors.forename: Choon Nam
authors.initials: CN
authors.lastname: Ong
mesh_terms: D000818:Animals; D003621:Daphnia / Q000378:metabolism*; D055432:Metabolomics; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry
chemical_list: D012834:Silver
keywords: AgNPs; Chronic toxicity; Daphnia; Life-cycle; Metabolomics