title: Lethal and sublethal effects of phthalate diesters in Silurana tropicalis larvae.
abstract: Phthalates are compounds used in polymers to increase their flexibility and are now ubiquitous in the environment as a result of widespread use. Because few studies have focused on the adverse effects of these chemicals in aquatic species, the present study aimed to determine the effects of phthalate diesters in amphibians. Western clawed frog (Silurana tropicalis) tadpoles were acutely exposed to water spiked with monomethyl phthalate (MMP; 1.3-1595.5 mg/L), dimethyl phthalate (DMP; 0.03-924.0 mg/L), or dicyclohexyl phthalate (DCHP; 0.3-99.3 mg/L). Because few studies have addressed the toxicity of these specific phthalates in most organisms, the present study used higher concentrations of these chemicals to determine their toxicity pathways in amphibians and at the same time investigate a suite of genes known to be altered by the well-studied phthalates. Both DMP and DCHP increased larval mortality (9.1-924.0 mg/L DMP and 4.1-99.3 mg/L DCHP), increased frequency of malformations in tadpoles (0.1-34.1 mg/L DMP and 4.1-19.0 mg/L DCHP), and up-regulated cellular stress-related messenger-RNA (mRNA) levels (4.1 mg/L DCHP). To characterize the molecular toxicity pathway of these phthalates in tadpoles, transcriptome analysis was conducted using a custom microarray. Parametric analysis of gene set enrichment revealed important changes in the expression of genes related to drug metabolism and transport, liver metabolism, xenobiotic clearance, and xenobiotic metabolism after DMP and DCHP treatments, although these responses were less pronounced with MMP (the metabolite of DMP). The present study is one of the few studies that demonstrated complementarity between gene expression analysis and organismal effects. Environ Toxicol Chem 2016;35:2511-2522. © 2016 SETAC.
authors.affiliation: Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, Ontario, Canada.
authors.forename: Justine
authors.initials: J
authors.lastname: Mathieu-Denoncourt
authors.affiliation: Department of Physiological Sciences and Center for Environmental and Human Toxicology, UF Genetics Institute, University of Florida, Gainesville, Florida, USA.|Department of Biology, University of New Brunswick and Canadian Rivers Institute, New Brunswick, Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Martyniuk
authors.affiliation: Department of Biology, University of New Brunswick and Canadian Rivers Institute, New Brunswick, Canada.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Loughery
authors.affiliation: Department of Chemical Engineering, McGill University, Quebec, Canada.
authors.forename: Viviane
authors.initials: V
authors.lastname: Yargeau
authors.affiliation: Wildlife and Landscape Science Directorate, Environment and Climate Change Canada, Burlington, Ontario, Canada.
authors.forename: Shane R
authors.initials: SR
authors.lastname: de Solla
authors.affiliation: Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, Ontario, Canada. valerie.langlois@rmc.ca.
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Langlois
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D007814:Larva / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D010795:Phthalic Acids / Q000633:toxicity*; D016019:Survival Analysis; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014981:Xenopus
chemical_list: D010795:Phthalic Acids; D014874:Water Pollutants, Chemical; C024629:dimethyl phthalate; C517284:monomethyl phthalate; C036042:dicyclohexyl phthalate
keywords: Frogs; Gene expression; Microarray; Plasticizers; Toxicity