Assessing mechanisms of toxicant response in the amphipod Melita plumulosa through transcriptomic profiling

• Published in: Aquatic toxicology 2014-01, Vol.146, p.247-257
• Main Authors: Hook, Sharon E., Osborn, Hannah L., Spadaro, David A., Simpson, Stuart L.
• Format: Article
• Language: English
• Subjects: Amphipod; Amphipoda - drug effects; Amphipoda - genetics; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Fundamental and applied biological sciences. Psychology; Gene expression; Genomics; Insecticides; Melita; Metals; Microarray; Mode of action; Oil; Transcriptome - drug effects; Water Pollutants, Chemical - toxicity
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2013.11.001

•The amphipod Melita plumulosa was exposed to different model toxicants, and its transcriptome profiled via microarray.•Each toxicant produced a unique gene expression profile, including closely related compounds.•These gene expression profiles could be linked to contaminant mode of action. This study describes the function of transcripts with altered abundance in the epibenthic amphipod, Melita plumulosa, following whole-sediment exposure to a series of common environmental contaminants. M. plumulosa were exposed for 48h to sediments spiked and equilibrated with the following contaminants at concentrations predicted to cause sublethal effects to reproduction: porewater ammonia 30mgL−1; bifenthrin at 100μgkg−1; fipronil at 50μgkg−1; 0.6% diesel; 0.3% crude oil; 250mgCukg−1; 400mgNikg−1; and 400mgZnkg−1. RNA was extracted and hybridized against a custom Agilent microarray developed for this species. Although the microarray represented a partial transcriptome and not all features on the array could be annotated, unique transcriptomic profiles were generated for each of the contaminant exposures. Hierarchical clustering grouped the expression profiles together by contaminant class, with copper and zinc, the petroleum products and nickel, and the pesticides each forming a distinct cluster. Many of the transcriptional changes observed were consistent with patterns previously described in other crustaceans. The changes in the transcriptome demonstrated that contaminant exposure caused changes in digestive function, growth and moulting, and the cytoskeleton following metal exposure, whereas exposure to petroleum products caused changes in carbohydrate metabolism, xenobiotic metabolism and hormone cycling. Functional analysis of these gene expression profiles can provide a better understanding of modes of toxic action and permits the prediction of mixture effects within contaminated ecosystems.