title: Growth inhibition and altered gene transcript levels in earthworms (Eisenia fetida) exposed to 2,2',4,4'-tetrabromodiphenyl ether.
abstract: The toxic effects of the ubiquitous pollutant 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on the earthworm Eisenia fetida were assessed by determining growth-inhibition and gene transcript levels of superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST), and transcriptional changes of the stress-response gene (heat-shock protein 70 [Hsp70]). Somatic growth and growth-inhibition rates in all BDE-47-treated groups were significantly different from those of the controls. The SOD gene transcripts were upregulated at all exposure doses and reached the maximum at the concentration of 400 mg/kg dry weight (dw) (3.84-fold, P < 0.01), which protected earthworms from oxidative stresses. However, downregulation of CAT and Hsp70 was present in all exposure doses and reached to the minimum at concentrations of 400 mg/kg dw (0.07-fold, P < 0.01 and 0.06-fold, P < 0.01, respectively). Upregulation of GST gene transcript level presented significant changes at concentrations of 10 (2.69-fold, P < 0.05) and 100 mg/kg dw (2.55-fold, P < 0.05). SOD maintained a dynamic balance to upregulate SOD expression to eliminate superoxide radicals in all dosage treatments, but downregulation of CAT decreased the ability to eliminate hydrogen peroxide. These changes could result in biochemical and physiological disturbances in earthworms.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Xiang-Bo
authors.initials: XB
authors.lastname: Xu
authors.forename: Ya-Juan
authors.initials: YJ
authors.lastname: Shi
authors.forename: Yong-Long
authors.initials: YL
authors.lastname: Lu
authors.forename: Xiao-Qi
authors.initials: XQ
authors.lastname: Zheng
authors.forename: R J
authors.initials: RJ
authors.lastname: Ritchie
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D005982:Glutathione Transferase / Q000378:metabolism; D006131:Growth Inhibitors / Q000633:toxicity*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D055768:Halogenated Diphenyl Ethers / Q000633:toxicity*; D009835:Oligochaeta / Q000254:growth & development*; D018384:Oxidative Stress; D012989:Soil Pollutants / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D006131:Growth Inhibitors; D018840:HSP70 Heat-Shock Proteins; D055768:Halogenated Diphenyl Ethers; D012989:Soil Pollutants; C511295:2,2',4,4'-tetrabromodiphenyl ether; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase