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Metal distribution and metallothionein induction after cadmium exposure in the terrestrial snail Helix aspersa (Gastropoda, Pulmonata)
Author(s) -
Hispard Florian,
Schuler Dietmar,
de Vaufleury Annette,
Scheifler Renaud,
Badot PierreMarie,
Dallinger Reinhard
Publication year - 2008
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-232.1
Subject(s) - metallothionein , pulmonata , helix pomatia , biology , snail , gastropoda , gene isoform , complementary dna , biochemistry , amino acid , hepatopancreas , cadmium , cytosol , microbiology and biotechnology , chemistry , ecology , gene , enzyme , organic chemistry
The aim of the present work was to study the effect of Cd 2+ exposure on metallothionein (MT) induction and on the distribution of metals (Cd, Cu, and Zn) in the terrestrial pulmonate Helix aspersa . In particular, the soluble and nonsoluble pools of the accumulated metals and their tissue distribution in uncontaminated and contaminated edible snails were investigated after a two‐week exposure to Cd 2+ . In the soluble cytosolic pool of the midgut gland of H. aspersa , three metal‐specific putative MT isoforms were separated following a fractionation protocol with diethylaminoethyl cellulose, size‐exclusion chromatography, ultrafiltration, and reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Interestingly, one of the above isoforms seems to bind both Cd and Cu, which may in addition mobilize, after induction by Cd 2+ , some of the intracellular Cu and, thus, perhaps increase the Cu pool in the cytosolic fraction. The cDNA and its translated amino acid sequence of a Cd 2+ ‐binding MT isoform from the snail midgut gland was characterized and attributed to one of the putative MT isoforms obtained by RP‐HPLC. The amino acid sequence of this Cd‐MT isoform of H. aspersa differed from similar sequences described in other terrestrial pulmonates, such as Helix pomatia or Arianta arbustorum , by only a few amino acids ( n = 4 and 8, respectively). That the identified Cd‐MT from H. aspersa is inducible by Cd 2+ also was shown, chromatographic evidence aside, by a specific polymerase chain reaction protocol on a cDNA basis, which included a noninducible housekeeping gene as a control.