Author/Editor		Žnidaršič, N; Tušek-Žnidarič, M; Falnoga, I; Ščančar, J; Štrus, J
Title		Metallothionein-like proteins and zinc-copper interaction in the hindgut of Porcellio scaber (Crusatea: Isopoda) expsed to zinc
Type		članek
Source		Biol Trace Elem Res
Vol. and No.		Letnik 106
Publication year		2005
Volume		str. 253-64
Language		eng
Abstract		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 metabolism of copper (Cu) and zinc (Zn). Dietary Zn supplementation (793 ug 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 Ve/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.
Descriptors		CRUSTACEA FOOD CONTAMINATION ZINC COPPER METALLOTHIONEIN CYTOSOL DIGESTIVE SYSTEM MOLTING SPECTROPHOTOMETRY, ATOMIC ABSORPTION CHROMATOGRAPHY, HIGH PRESSURE LIQUID