engleski

Application of hyphenated analytical techniques for the assessment of the environmental metal exposure

Depending on their concentration non essential but also essential trace metals and metalloids can cause toxic effects on living organisms. Determination of the total content of selected metals in biological tissue is regularly implemented in environmental monitoring programs, but this is insufficient for the metal exposure assessment. On the other hand, the early effects of metal contamination can be already observed at the molecular and cellular level of an organism chronically exposed to even low doses and in this way may serve as an “early warning” indicator. Response of an organism to metal charge can be achieved by binding metals to various cytosolic biomolecules as ligands. Therefore, the investigation of cytosolic profiles of metals bound to biomolecules of different molecular size can be of great importance as a first step in defining possible biomarkers of metal exposure in the field of pollution monitoring. Coupling size exclusion high performance liquid chromatography (SE-HPLC) with online detection by a sensitive and multi element isotope detector such as an ICP-MS represents an excellent combination which enables obtaining such information. In this contribution cytosolic patterns of metals associated with biomolecules of different molecular size present in the digestive gland of wild mussels (Mytilus galloprovincialis) as a common bioindicator organism were studied. Mussels’ cytosol-protein profiles from several marinas and harbours considered as fairly polluted areas and reference location were compared. Size exclusion chromatography was performed at Superdex 75 (molecular weight range: 3 kDa – 70 kDa) and Superdex 200 (molecular weight range 10 kDa – 600 kDa) in order to obtain profiles for selected metals bound to a wide range of molecular size biomolecules. Metal profiles from more polluted locations have indicated increased intensities in chromatographic fractions related to specific biomolecule size ranges, which are characteristic for selected known metal containing biomarkers for that specific metal (such as metallothionein for Cu, Zn and/or Cd). Preparative chromatography of these fractions can be a starting point for subsequent purification and identification of proteins with the final goal of defining a set of biomarkers specific for metal pollution. This study was performed within the scope of the DAAD project (Project-ID 50752021 Deutscher Akademischer Austausch Dienst) during which scientific collaboration between the research groups from Croatia and Germany has been established.

metal exposure; SE-HPLC-ICP-MS; cytosolic metal profiles

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