title: Isoform-specific quantification of metallothionein in the terrestrial gastropod Helix pomatia. II. A differential biomarker approach under laboratory and field conditions.
abstract: The two function-specific metallothionein (MT) isoforms characterized from the midgut gland and mantle tissue of Helix pomatia differ substantially in their metal-binding preferences, as well as molecular and biochemical features. These differences make them potential candidates for biomarker studies based on a differential, isoform-specific approach. To prove this hypothesis, induction experiments with two metals (Cd and Cu) that are normally bound by the two isoforms were compared with a range of organic chemicals and physical stressors under laboratory conditions to test the responsiveness of the two isoforms to the stressors applied. In addition, field studies were conducted with Roman snails and substrate samples collected from different metal-contaminated sites in Austria to test the suitability of the two isoforms as biomarkers under field conditions. The results of these combined laboratory and field studies confirmed the validity of the biomarker approach with the two metal- and tissue-specific isoforms. It is demonstrated that the Cd-binding MT specifically and exclusively responds to Cd exposure by increasing concentrations, whereas the Cu-binding MT isoform decreases in its concentration upon exposure to physical stress (X-ray irradiation and cold). This suggests researchers should adopt, under certain preconditions, a dual biomarker approach by combining the simultaneous quantification of Cd-MT concentrations in the midgut gland as a biomarker for Cd pollution and of Cu-MT concentration in the mantle as a biomarker for the impairment of snails by additional physical stressors.
authors.affiliation: Institut für Zoologie und Limnologie (Abteilung Okophysiologie), der Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria. reinhard.dallinger@uibk.ac.at
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dallinger
authors.forename: Monika
authors.initials: M
authors.lastname: Chabicovsky
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lagg
authors.forename: Rouven
authors.initials: R
authors.lastname: Schipflinger
authors.forename: Harald G
authors.initials: HG
authors.lastname: Weirich
authors.forename: Burkhard
authors.initials: B
authors.lastname: Berger
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D002104:Cadmium / Q000633:toxicity*; D003300:Copper / Q000633:toxicity*; D004064:Digestive System; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000633:toxicity*; D006372:Helix, Snails / Q000502:physiology*; D008668:Metallothionein / Q000032:analysis* / Q000737:chemistry*; D020033:Protein Isoforms; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling
chemical_list: D015415:Biomarkers; D004785:Environmental Pollutants; D020033:Protein Isoforms; D002104:Cadmium; D003300:Copper; D008668:Metallothionein