Role of metallothioneins in superoxide radical generation during copper redox cycling: defining the fundamental function of metallothioneins.

In order to demonstrate the in vivo antioxidant properties of metallothioneins (MTs), the bacteria Escherichia coli was used as a cell reactor in which we compared the metal binding and antioxidative functions of MTs from different species, with different structures and polypeptide lengths. No protective effects of cytoplasmic MTs from cadmium (Cd) or zinc (Zn) contamination were observed in a wild-type E. coli strain, although these MTs can efficiently bind both Cd and Zn.

Cytochrome c oxydase subunit I gene is up-regulated by cadmium in freshwater and marine bivalves.

Inhibition of the mitochondrial electron transfer chain and induction of reactive oxygen species (ROS) production are one of the roots of cadmium (Cd) toxicity. To appreciate the impact of Cd on mitochondria, we focused on the expression of CoxI gene which encodes the subunit I of the Cytochrome c oxidase (complex IV of the respiratory chain). CoxI gene expression was studied by real-time quantitative PCR in three species: two freshwater bivalves (Corbicula fluminea and Dreissena polymorpha) and one marine bivalve (diploid or triploid Crassostrea gigas).

Heterologous expression of bacterial and human multidrug resistance proteins protect Escherichia coli against mercury and zinc contamination.

In order to determine the role of multidrug resistance proteins in mercury and zinc resistance, human MDR1, Lactococcus lactis lmrA, and Oenococcus oeni omrA genes were expressed in an Escherichia coli tolC mutant which is hypersensitive to metals. The three transporters conferred an increased mercury and zinc resistance to E. coli as compared to the control bacteria.

cDNA cloning and gene expression of ribosomal S9 protein gene in the mollusk Corbicula fluminea: a new potential biomarker of metal contamination up-regulated by cadmium and repressed by zinc.

Biological indicators can be used to assess polluted sites, but their success depends on their specificity. The aim of the present study was to identify a specific cadmium biomarker of the freshwater bivalve Corbicula fluminea. Differential display technique was used to identify new molecular indicators for cadmium exposure.

Heterologously expressed bacterial and human multidrug resistance proteins confer cadmium resistance to Escherichia coli.

The human MDR1 gene is induced by cadmium exposure although no resistance to this metal is observed in human cells overexpressing hMDR1. To access the role of MDR proteins in cadmium resistance, human MDR1, Lactococcus lactis lmrA, and Oenococcus oeni omrA were expressed in an Escherichia coli tolC mutant strain which proved to be hypersensitive to cadmium. Both the human and bacterial MDR genes conferred cadmium resistance to E.