Daphnia magna Ecotoxicogenomics Provides Mechanistic Insights into Metal Toxicity

• Published in: Environmental science & technology Vol. 41; no. 3; pp. 1044 - 1050
• Main Authors: Poynton, Helen C, Varshavsky, Julia R, Chang, Bonnie, Cavigiolio, Giorgio, Chan, Sarah, Holman, Patricia S, Loguinov, Alexandre V, Bauer, Darren J, Komachi, Kelly, Theil, Elizabeth C, Perkins, Edward J, Hughes, Owen, Vulpe, Chris D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.02.2007
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Biomarkers; Cadmium - toxicity; Chitinases - antagonists & inhibitors; Chitinases - metabolism; Copper - toxicity; Crustaceans; Daphnia - drug effects; Daphnia - metabolism; Daphnia magna; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Ferritins - genetics; Ferritins - metabolism; Food chains; Freshwater; Fundamental and applied biological sciences. Psychology; Gene expression; Genome - drug effects; Genomics; Metals; Metals - toxicity; Oligonucleotide Array Sequence Analysis; RNA, Messenger - genetics; RNA, Messenger - metabolism; Toxicity; Toxicogenetics; Toxicology; Water Pollutants, Chemical - toxicity; Zinc - toxicity; Toxicity; Cladocera; Biological marker; Biological indicator; Gene expression; Heavy metal; Crustacea; Freshwater environment; Pollutant; Arthropoda; Water pollution; Invertebrata; Branchiopoda; Zooplankton; Daphnia magna
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0615573

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.