title: Distinct transcriptomic responses of Caenorhabditis elegans to pristine and sulfidized silver nanoparticles.
abstract: Manufactured nanoparticles (MNP) rapidly undergo aging processes once released from products. Silver sulfide (Ag2S) is the major transformation product formed during the wastewater treatment process for Ag-MNP. We examined toxicogenomic responses of pristine Ag-MNP, sulfidized Ag-MNP (sAg-MNP), and AgNO3 to a model soil organism, Caenorhabditis elegans. Transcriptomic profiling of nematodes which were exposed at the EC30 for reproduction for AgNO3, Ag-MNP, and sAg-MNP resulted in 571 differentially expressed genes. We independently verified expression of 4 genes (numr-1, rol-8, col-158, and grl-20) using qRT-PCR. Only 11% of differentially expressed genes were common among the three treatments. Gene ontology enrichment analysis also revealed that Ag-MNP and sAg-MNP had distinct toxicity mechanisms and did not share any of the biological processes. The processes most affected by Ag-MNP relate to metabolism, while those processes most affected by sAg-MNP relate to molting and the cuticle, and the most impacted processes for AgNO3 exposed nematodes was stress related. Additionally, as observed from qRT-PCR and mutant experiments, the responses to sAg-MNP were distinct from AgNO3 while some of the effects of pristine MNP were similar to AgNO3, suggesting that effects from Ag-MNP is partially due to dissolved silver ions.
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, 1100 South Limestone Street, Lexington, KY 40546, United States.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Starnes
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, 1100 South Limestone Street, Lexington, KY 40546, United States; Center for Environmental Implications of NanoTechnology (CEINT), P.O. Box 90287, Duke University, Durham, NC 27708-0287, United States.
authors.forename: Stuart S
authors.initials: SS
authors.lastname: Lichtenberg
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, 1100 South Limestone Street, Lexington, KY 40546, United States; Center for Environmental Implications of NanoTechnology (CEINT), P.O. Box 90287, Duke University, Durham, NC 27708-0287, United States.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Unrine
authors.affiliation: Department of Statistics, University of Kentucky, 725 Rose Street, MDS Building 305, Lexington, KY 40536, United States.
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Starnes
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, 1100 South Limestone Street, Lexington, KY 40546, United States.
authors.forename: Emily K
authors.initials: EK
authors.lastname: Oostveen
authors.affiliation: Center for Environmental Implications of NanoTechnology (CEINT), P.O. Box 90287, Duke University, Durham, NC 27708-0287, United States; Department of Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States.
authors.forename: Gregory V
authors.initials: GV
authors.lastname: Lowry
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, 1100 South Limestone Street, Lexington, KY 40546, United States; Center for Environmental Implications of NanoTechnology (CEINT), P.O. Box 90287, Duke University, Durham, NC 27708-0287, United States; Division of Land and Water, CSIRO, Ecosciences Precinct, Brisbane, QLD, Australia.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Bertsch
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, 1100 South Limestone Street, Lexington, KY 40546, United States; Center for Environmental Implications of NanoTechnology (CEINT), P.O. Box 90287, Duke University, Durham, NC 27708-0287, United States. Electronic address: olga.tsyusko@uky.edu.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Tsyusko
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000633:toxicity*; D012834:Silver / Q000633:toxicity*; D018030:Silver Compounds / Q000633:toxicity*; D012835:Silver Nitrate / Q000633:toxicity*; D059467:Transcriptome / Q000187:drug effects*; D062065:Wastewater
chemical_list: D012834:Silver; D018030:Silver Compounds; D012835:Silver Nitrate; D062065:Wastewater; C013251:silver sulfide
keywords: Antimicrobial; Nanomaterial; Soil; Toxicogenomics; Wastewater