title: Daphnia magna ecotoxicogenomics provides mechanistic insights into metal toxicity.
abstract: Toxicogenomics has provided innovative approaches to chemical screening, risk assessment, and predictive toxicology. If applied to ecotoxicology, genomics tools could greatly enhance the ability to understand the modes of toxicity in environmentally relevant organisms. Daphnia magna, a small aquatic crustacean, is considered a "keystone" species in ecological food webs and is an indicator species for toxicant exposure. Our objective was to demonstrate the potential utility of gene expression profiling in ecotoxicology by identifying novel biomarkers and uncovering potential modes of action in D. magna. Using a custom D. magna cDNA microarray, we identified distinct expression profiles in response to sublethal copper, cadmium, and zinc exposures and discovered specific biomarkers of exposure including two probable metallothioneins, and a ferritin mRNA with a functional IRE. The gene expression patterns support known mechanisms of metal toxicity and reveal novel modes of action including zinc inhibition of chitinase activity. By integrating gene expression profiling into an environmentally important organism, this study provides experimental support for the utility of ecotoxicogenomics.
authors.affiliation: Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA.
authors.forename: Helen C
authors.initials: HC
authors.lastname: Poynton
authors.forename: Julia R
authors.initials: JR
authors.lastname: Varshavsky
authors.forename: Bonnie
authors.initials: B
authors.lastname: Chang
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cavigiolio
authors.forename: Sarah
authors.initials: S
authors.lastname: Chan
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Holman
authors.forename: Alexandre V
authors.initials: AV
authors.lastname: Loguinov
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Bauer
authors.forename: Kelly
authors.initials: K
authors.lastname: Komachi
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Theil
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Perkins
authors.forename: Owen
authors.initials: O
authors.lastname: Hughes
authors.forename: Chris D
authors.initials: CD
authors.lastname: Vulpe
mesh_terms: D000818:Animals; D002104:Cadmium / Q000633:toxicity; D002688:Chitinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003300:Copper / Q000633:toxicity; D003621:Daphnia / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005293:Ferritins / Q000235:genetics / Q000378:metabolism; D016678:Genome / Q000187:drug effects*; D008670:Metals / Q000633:toxicity*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043922:Toxicogenetics; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015032:Zinc / Q000633:toxicity
chemical_list: D008670:Metals; D012333:RNA, Messenger; D014874:Water Pollutants, Chemical; D002104:Cadmium; D003300:Copper; D005293:Ferritins; D002688:Chitinases; D015032:Zinc