Metallothionein response following cadmium exposure in the oligochaete Eisenia fetida.
We studied the metallothionein (MT) response in cadmium-exposed worms (Eisenia fetida) both at the protein level by Dot Immunobinding Assay (DIA) with a polyclonal antibody raised against the most immunogenic part of this protein and at the expression level by Northern blotting using a specific probe. MT appeared as two close isoforms. DIA results clearly demonstrated significant differences in MT level of whole worm heat-treated supernatants between E. fetida exposed to Cd concentrations as low as 8 mg Cd kg(-1) of dry soil compared to controls. Northern blotting analysis performed on whole bodies of worms revealed that a single exposure to 8 mg Cd kg(-1) of dry soil for 1 day resulted in the production of MT mRNA. This response was maintained for exposure of at least 1 month. Clear differences of MT gene expression were also observed between worms exposed to different Cd concentrations (8, 80 or 800 mg Cd kg(-1) of dry soil). Immunocytochemistry demonstrated that MT was located in the chloragogenous tissue surrounding the gut where metals are known to be accumulated. This work revealed that E. fetida MT is a sensitive and relevant biomarker of Cd exposure and especially when considering gene expression response. Further experiments have now to prove its usefulness in natural metal-contaminated soil toxicity assessments.
Demuynck
Sylvain
S
Laboratoire d'Ecologie Numérique et d'Ecotoxicologie, UPRES EA 3570, FR 1818 CNRS, Université des Sciences et Technologies de Lille, F-59655 Villeneuve d'Ascq Cedex, France. sylvain.demuynck@univ-lille1.fr
Grumiaux
Fabien
F
Mottier
Violaine
V
Schikorski
David
D
Lemière
Sébastien
S
Leprêtre
Alain
A
D000818:Animals; D002104:Cadmium / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects; D008668:Metallothionein / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D009835:Oligochaeta / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D013438:Sulfhydryl Compounds / Q000032:analysis
D012333:RNA, Messenger; D012989:Soil Pollutants; D013438:Sulfhydryl Compounds; D002104:Cadmium; D008668:Metallothionein