RESEARCH

Our main research topic is divided into 3 axes

Subcellular mechanisms of metal detoxification and metal toxicity in aquatic organisms

Organisms have developed a variety of complementary strategies to protect their cells from metal toxicity. These strategies include metal sequestration in subcellular compartments such as cytosolic metal-binding proteins (metallothioneins or metallothionein-like proteins) and metal-rich granules.

However, trace metals can avoid these detoxification-related responses and then have inappropriate binding to physiologically sensitive targets such as biomolecules and organelles, provoking deleterious effects.

We are interested in determining the detoxification responses used by aquatic organisms from one metal to another, as well as in identifying the principal sensitive sites targeted by these contaminants. Metals of the great toxicology concern can also be identified by determining the relative proportions of metal accumulated in the detoxified-metal and metal-sensitive compartments.

Identification of the intracellular biomolecules targeted by trace metals as detected by hyphenated techniques

Once subcellular metal partitioning measurements have been done, information is available on the fractions where high metal accumulation occurs.

In these fractions, hyphenated techniques which combine on-line high resolution chromatographic techniques with elemental or molecular mass spectrometric analyses (e.g., SEC-ICP-QQQ, nHPLC-ICP-QQQ, nHPLC-MS-MS) are applied.

Such techniques yield useful information about the biochemical properties of the metal–biomolecule complexes and further our understanding of metal interactions with subcellular biomolecules involved in metal toxicity. Similar to subcellular metal partitioning studies, these techniques are applied to several aquatic organisms collected from metal-impacted regions or laboratory exposures.

Impacts of trace metals on biochemical and physiological responses in metal-contaminated organisms

Once subcellular targets of trace metal have been identified, the biochemical and physiological consequences of metal binding to these biomolecules are determined. Special attention is paid to some subcellular fractions such as mitochondria and microsomes where important metabolic pathways take place.

Using biochemical parameters (O₂ consumption, ATP production, ROS production, metabolic rates), and other approaches related to proteomics and metabolomics, we look at the effects of trace metals on the cellular functions in the aquatic organism studies by our research group.

These studies are performed in different living cells varying from algae to fish and marine mammals, in laboratory-exposed models as well in field-collected organisms.