title: Metallothionein response to cadmium and zinc exposures compared in two freshwater bivalves, Dreissena polymorpha and Corbicula fluminea.
abstract: Metallothionein (MT) response to cadmium (Cd) and zinc (Zn) bioaccumulation after single or combined direct exposure was compared in two freshwater bivalves, Dreissena polymorpha (zebra mussel) and Corbicula fluminea (Asiatic clam). Bivalves were exposed to 0.133 microM Cd and/or 15.3 microM Zn, with metal and MT concentrations analysed in the whole soft body after 1, 3, 10 and 24 days of exposure and compared with controls. Results showed significant increase in MT concentrations in both species exposed to Cd and Cd+Zn with a higher accumulation of the protein compared to the control in D. polymorpha for nevertheless similar Cd levels accumulated with time. Exposure to Zn alone led to a significant increase in MT concentrations only in C. fluminea, whereas there was a lack of MT gene induction in the zebra mussels which was confirmed by MT mRNA quantification in gills (RT-PCR). Mussel mortality after 10 days of exposure to Zn and Cd + Zn is discussed with regard to detoxification mechanisms, which include metallothioneins.
authors.affiliation: Laboratoire d'Ecophysiologie et Ecotoxicologie des Systèmes Aquatiques, LEESA, Université Bordeaux 1/UMR CNRS 5805, Place du Dr Peyneau, 33120, Arcachon, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Marie
authors.forename: Patrice
authors.initials: P
authors.lastname: Gonzalez
authors.forename: Magalie
authors.initials: M
authors.lastname: Baudrimont
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Bourdineaud
authors.forename: Alain
authors.initials: A
authors.lastname: Boudou
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D049874:Corbicula / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D049875:Dreissena / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D005618:Fresh Water; D015870:Gene Expression / Q000187:drug effects; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D015032:Zinc / Q000378:metabolism / Q000633:toxicity*
chemical_list: D012333:RNA, Messenger; D002104:Cadmium; D008668:Metallothionein; D015032:Zinc