title: Toxicogenomic responses of nanotoxicity in Daphnia magna exposed to silver nitrate and coated silver nanoparticles.
abstract: Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO(3) and AgNPs have distinct expression profiles suggesting different modes of toxicity. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO(3) caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed.
authors.affiliation: Department of Environmental, Earth and Ocean Sciences, University of Massachusetts, Boston, Boston, MA 02125, United States. Helen.poynton@umb.edu
authors.forename: Helen C
authors.initials: HC
authors.lastname: Poynton
authors.forename: James M
authors.initials: JM
authors.lastname: Lazorchak
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Impellitteri
authors.forename: Bonnie J
authors.initials: BJ
authors.lastname: Blalock
authors.forename: Kim
authors.initials: K
authors.lastname: Rogers
authors.forename: H Joel
authors.initials: HJ
authors.lastname: Allen
authors.forename: Alexandre
authors.initials: A
authors.lastname: Loguinov
authors.forename: J Lee
authors.initials: JL
authors.lastname: Heckman
authors.forename: Shekar
authors.initials: S
authors.lastname: Govindasmawy
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D016000:Cluster Analysis; D003621:Daphnia / Q000187:drug effects* / Q000235:genetics*; D004781:Environmental Exposure / Q000032:analysis*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D007477:Ions; D053768:Metal Nanoparticles / Q000633:toxicity*; D015203:Reproducibility of Results; D012834:Silver / Q000633:toxicity*; D012835:Silver Nitrate / Q000633:toxicity*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D023382:Toxicity Tests, Acute; D043922:Toxicogenetics
chemical_list: D015415:Biomarkers; D007477:Ions; D012834:Silver; D012835:Silver Nitrate