Improved separation of perch liver metallothionein by fast protein liquid chromatography

Fully automated two-step assay for detection of metallothionein through magnetic isolation using functionalized γ-Fe2O3 particles

Metallothioneins (MTs) are involved in heavy metal detoxification in a wide range of living organisms. Currently, it is well known that MTs play substantial role in many pathophysiological processes, including carcinogenesis, and they can serve as diagnostic biomarkers. In order to increase the applicability of MT in cancer diagnostics, an easy-to-use and rapid method for its detection is required. Hence, the aim of this study was to develop a fully automated and high-throughput assay for the estimation of MT levels. Here, we report the optimal conditions for the isolation of MTs from rabbit liver and their characterization using MALDI-TOF MS. In addition, we described a two-step assay, which started with an isolation of the protein using functionalized paramagnetic particles and finished with their electrochemical analysis. The designed easy-to-use, cost-effective, error-free and fully automated procedure for the isolation of MT coupled with a simple analytical detection method can provide a prototype for the construction of a diagnostic instrument, which would be appropriate for the monitoring of carcinogenesis or MT-related chemoresistance of tumors.

Function of metallothioneins in carp Cyprinus carpio from two field sites in Western Ukraine

The aim of the present study was to elucidate the seasonal and spatial regularity of the properties of metallothioneins (MT) from the liver and gills of carp Cyprinus carpio L. in rural (R) and industrial (I) sites in Western Ukraine. The MT is represented by two chromatographic forms, the features of which exhibit seasonal rather than spatial dependence. The pronounced differences between the sites were due to the lower levels of Zn in the liver and the higher levels of Zn in MT of carp from site I, providing evidence of the higher overall anthropogenic impact here that leads to the distortion of this essential metal accumulation and to the activation of metal-binding function of MT. In spring, higher levels of Cu and Cd in MT and in the tissues were reflected at site R probably as the result of the permitting pollution here. The principal component analysis demonstrated the correlation of MT-bound metal levels to their levels in water and the absence of such relation for general tissue metal levels for Zn.

Seasonal and spatial comparison of metallothioneins in frog Rana ridibunda from feral populations

The aim of this study was to elucidate the seasonal and spatial regularity of the properties of metallothioneins (MTs) from the liver and kidney of the frog Rana ridibunda in rural (R) and urban (U) sites in Western Ukraine. This allowed examination of their possibility use in biomonitoring of environmental quality. The positive correlation for Zn and negative correlation for Cu were reflected between their content in the liver and MTs. The content of MTs was higher in summer compared to other seasons and also at the U site compare to the R site. MTs had been comprised of two chromatographic forms (MT-1 and MT-2/MT-2a), with lesser and variable MT-2/2a in frogs from the U site, particularly in the kidney. MTs accumulated about 75% of Cd in the liver. In summary, the ability MTs to elevate content as a stress response, together with the sensitivity of MT-2, may be explored to understand the health status of the frog in each season, reflecting the higher overall anthropogenic impact at the U site.

Properties of cod metallothionein, its presence in different tissues and effects of Cd and Zn treatment

One isoform of the low-molecular-weight metal-binding protein metallothionein (MT) has been isolated from the liver of Atlantic cod by size-exclusion and ion-exchange chromatography. Cod MT contained 33% cysteine, no aromatic amino acids or arginine. As is the case for other piscine MTs, the N-terminus of cod MT lacked the asparagine in position 4 which is present in mammalian MTs. In addition, cod MT differed from all other vertebrate MTs described in that the N-terminal methionine was not acetylated. Antibodies were raised in rabbits against hepatic MT from cod by repeated injections of native protein mixed with adjuvant. Anti-cod MT antisera cross reacted with similarly-sized proteins in liver, brain, anterior kidney, posterior kidney, spleen, intestine, gills and ovaries. The putative MT in cod brain migrated differently to that of the other tissues in native gel electrophoresis. Intraperitoneally injected Cd (1 mg/kg) was nearly entirely associated with the MT-peak in hepatic and renal cytosols, whereas a single injection of Zn (10 mg/kg) resulted in increases in all cytosolic Zn pools of the liver and no apparent change in cytosolic Zn, Cu, Ni or Cd in kidney.

A radioimmunoassay for perch (Perca fluviatilis) metallothionein

A sensitive radioimmunoassay (RIA) for the measurement of metallothionein (MT) from perch (Perca fluviatilis) has been developed. The method is a double-antibody RIA with rabbit anti-perch MT serum as first antibody, goat anti-rabbit immunoglobulin G as second antibody, and perch MT conjugated to 125I-labeled Bolton-Hunter reagent as tracer. The rabbit antiserum raised against perch MT recognizes rainbow trout (Oncorhynchus mykiss) MT, but shows little cross-reactivity with horse MT. At a dilution of 1:2000, the MT antibodies bind 36% of the tracer when no cold ligand is present. The sensitivity of the assay is 15 pg perch MT per tube and the practical working range is 0.15-250 ng perch MT per tube. The RIA allows determination of MT in plasma or lysed blood cells at concentrations as low as 3.0 ng/ml and in tissues at levels above 9.0 ng/g (wet weight). Intra- and interassay coefficients of variation were 6 and 10%, respectively.