Metallothionein-like proteins and zinc-copper interaction in the hindgut of Porcellio scaber (crustacea: Isopoda) exposed to zinc
- 95 Downloads
Metallothioneins (MTs) are ubiquitous low-molecular-weight metalbinding proteins, with a variety of functions in metal metabolism ascribed to them. Among terrestrial invertebrates, MTs have been studied in nematodes, insects, snails, and earthworms. The aim of this study was the characterization of MT-like proteins in the terrestrial isopod crustacean Porcellio scaber in order to analyze their probable role in the metaboliss of copper (Cu) and zinc (Zn). Dietary Zn supplementation (793 μg Zn/g dry food, 6 d) was applied to stimulate MT synthesis. After separation of the hindgut postmicrosomic supernatant (cytosol) of Zn-exposed animals by gel filtration on a Sephadex G-75 column, a Cu- and Zn-containing peak was detected in the position of V c/Vo≈2, where MTs are expected to elute. Rechromatography of these fractions by size-exclusion chromatography-high-performance liquid chromatography revealed that the 215-nm absorbance peak coincided with the absorbance peak of the rabbit MT II standard. These low-molecular-weight Cu- and Zn-binding compounds, detected in the cytosol of the hindgut cells in Zn-exposed P. scaber. are considered to be Cu, Zn-MT-like proteins. To our knowledge, this is the first report on the characterization of MT-like proteins in isopod crustaceans. These results also indicate that both Zn and Cu dynamics in P. scaber hindgut are affected at the given dietary Zn supplementation and that MT-like proteins are involved in this Zn-Cu interaction.
Index EntriesMetallothionein copper zinc Porcellio scaber hindgut digestive system Crustacea
Unable to display preview. Download preview PDF.
- 2.Y. Kojima, P. A. Binz, and J. H. R. Kägi, Nomenclature of metallothionein: proposal for a revision, in Metallothionein IV, C. Klaassen, ed., Birkhauser-Verlag, Basel, pp. 3–6 (1999).Google Scholar
- 21.R. Dallinger and F. Prosi, Fractionation and identification of heavy metals in hepatopancreas of terrestrial isopods: evidence of lysosomal accumulation and absence of cadmium-thionein, in Proceedings of 3rd European Congress on Entomology, H. H. Velthuis, ed., Nederlandse Entomologische Vereniging, Amsterdam, p. 328 (1986).Google Scholar
- 22.H. E. van Capelleveen, Ecotoxicity of heavy metals for terrestrial isopods, PhD thesis, Free University Press, Amsterdam, pp. 79–89 (1987).Google Scholar
- 23.M. H. Donker, P. Koevoets, J. A. C. Verkleij, and N. M. Van Straalen, Metal binding compounds in hepatopancreas and heamolymph of Porcellio scaber (Isopoda), Comp. Biochem. Physiol. 97C(1), 119–126 (1990).Google Scholar
- 28.J. Štrus, D. Drobne, and P. Ličar, Comparative anatomy and functional aspects of the digestive system in amphibious and terrestrial isopods (Isopoda: Oniscidea), in Terrestrial Isopod Biology, M. A. Alikhan, ed., Balkema, Rotterdam, pp. 15–23 (1995).Google Scholar
- 29.M. Dermelj, A. Vakselj, V. Ravnik, and B. Smodiš, Applicability of carbamate extraction to radiochemical separation and determination of cadmium, cobalt, copper and zinc in various biosphere samples, Radiochem. Radioanal. Lett. 41, 149–160 (1979).Google Scholar
- 32.P. Zidar, Zinc and cadmium toxicity testing on test organism (Porcellio scaber, Isopoda, Crustacea), MSc thesis, University of Ljubljana (1998).Google Scholar
- 33.R. Eisler, Zinc hazards to fish, wildlife, and invertebrates: a synoptic review, Biological Report 10, US Department of the Interior Fish and Wildlife Service, Washington, DC (1993).Google Scholar
- 39.W. Wieser, Über die Häutung von Procellio scaber Latr., Verhandlungen der Deutschen Zoologischen Gesellschaft, Kiel, Leipzig, Germany, pp. 178–195 (1964).Google Scholar
- 40.I. Bremner and P. M. May, Systemic interactions of zinc, in Zinc in Human Biology, C. F. Mills, ed., Springer-Verlag, Berlin, pp. 95–108 (1989).Google Scholar