• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.276-282
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• 2004

Marginal Zn deficiency is prevalent through the world and yet human zinc status has not been properly assessed due to the lack of a reliable diagnostic indicator. One potential possibility for zinc status assessment using Zn-binding protein, metallothionein (MT)-mRNA, has been proposed. The purpose of the present study was aimed to show whether measurement of mononuclear cell (MNC) MT mRNA, using a competitive-reverse transcriptase-polymerase chain reaction (competitive-RT-PCR) assay, could indicate zinc status in human subjects. In this study, MNC MT-mRNA expression was measured using a competitive-RT-PCR to compare before and after 14 days of zinc supplementation (50 mg Zn/das zinc gluconate). RT-PCR oligonucleotide primers which were designed to amplify both a 278 bp segment of the human MT-2A cDNA and a 198 bp mutant competitor cDNA template from MNCs, were prepared. MT-2A mRNA was normalized by reference to the housekeeping gene, $\beta$-actin, mRNA for which was also measured by competitive-RT-PCR. There was considerable inter-individual variation in MT-mRNA concentration and yet, the mean MT-2A mRNA level increased 4.7-fold after Zn supplementation, as compared to before Zn supplementation. This MT-2A mRNA level was shown as the same pattern and, even more sensitive assay, compared to the conventional plasma and red blood cells (RBCs) Zn assessment in which plasma and RBCs zinc levels increased 2.3- and 1.2-fold, respectively (p<0.05). We suggest that MT competitive-RT-PCR can be a useful assessment tool for evaluating human zinc status.

• The Korean Journal of Zoology
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• v.36 no.4
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• pp.529-534
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• 1993

흰쥐의 신피질 세포막과 소포체 막을 분리하여 카드를 및 Metallothioneln(MT)을 투여하였을 때 세포막에 존재하는 Ca-ATPase에 미치는 영향을 측정하여 다음과 같은 결과를 얻었다. 전기영동상에서 분리된 MT가 분자량 12KD 정도의 위치에 band가 나타났으며, 분리한 각 세포의 막에 카드윰을 농도별로 처리하였을 때 고농도일수록 Ca-ATPase의 활성도가 감소하였으나, MT를 처리한 경우 신피질 세포막은 거의 대조군과 유사한 결과를 나타냈고, 소포체 막에 MT를 처리한 경우는 20mg/ml의 카드윰을 처리한 경우와 유사하였다. 이와같은 결과로 보아 카드윰은 세포막의 Ca-ATPase의 활성을 저하시켜 세포내 칼슘 항상성에 영향을 미치는 MT는 Ca-ATPase의 활성을 회복시켜 카드뮴에 의한 세포독성의 방어작용에 부분적으로 작용한 것으로 생각된다.

• Ocean and Polar Research
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• v.23 no.4
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• pp.337-345
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• 2001

A Cd-binding protein was identified in the renal cytosol of the Antarctic clam Laternula elliptica which naturally contains high concentrations of Cd. The Cd-binding protein showed similar characteristics of metallothionein (MT) in molecular weight (about 10-12 kDa) and low spectral absorbance at 280 nm with relatively high absorbance at 254nm. Results of immuno-histochemical staining suggested that the MT-like Cd-binding protein was mainly located in the epithelial cells of the kidney. The MT-like protein was a major ligand of cytosolic Cd as shown in the elution profiles of chromatography and may play an important role in Cd sequestration and accumulation in L. elliptica kidney. A considerable amount of Cd was also found to be associated with particulate fraction, indicating the sequestration to particulate fraction is as important as binding to the cytosolic MT-like protein in Cd accumulation in the kidney.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.489-494
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• 2007

Transcriptional modulation of metallothionein (MT) during acute metal exposures (cadmium, copper or zinc) was examined in fry of Hemibarbus mylodon, a threatened fish species in Korean peninsula. Viability of H. mylodon fry was most affected by copper exposure (up to 79% of mortality at 1 ppm for 48 hours) and considerably by cadmium exposure (21 to 54% of mortality). On the other hand, Zn showed the least adverse effect on the viability (0 to 13% of mortality) of this species. Based on the semi-quantitative RT-PCR analysis, the stimulation of MT mRNA in response to metal exposures followed generally in a dose-dependent fashion where cadmium was the most potent inducer for the induction of MT transcripts in fry (up to more than 5-fold) while the lowest response was observed in zinc-exposed group (2-fold at maximum). From the exposure using environmentally realistic doses of cadmium (0 to 0.05 ppm for 24 hours), MT expression at mRNA level was also sensitively modulated toward upregulation up to more than 3-fold as relative to non-exposed control. Results from the present study would be a good basis for understanding the adaptive capacity and stress physiology of this endangered fish species during metal pollution.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.426-429
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• 2000

Recombinant E. coli JM109(pZH3-5/pMT) harboring manganese transport gene(mntA) and metal sequestering protein, metallothionein(MT), was cultivated to accumulate cadmium in aqueous phase. Bioaccumulation followed Michaelis-Menten type kinetics. Equilibrium isotherm showed Langmuir type isotherm. The optimum pH for $Cd^{2+}$ uptake was 7-7.5.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.183-194
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• 1995

The purpose of this study was to investigate the effect of vitamin E on the synthesis of the metallothionein in the liver of streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats($220{\pm}10mg$) were randomly assigned to one control and three STZ-diabetic groups. Diabetic groups were classified to STZ-0E(vitamine E free diet), STZ-40E(40mg vitamin E/kg of diet) and STZ-400E(400mg vitamin E/kg of diet) according to the level of vitamin E supplementation. Blood glucose levels of STZ-diabetic rats were three times higher than that of control. The contents of vitamin E in liver were lower signifciantly STZ-0E, STZ-40E groups by 50%, 36% compared with that of control. Lipid peroxide values(LPO) in liver were higher 5.6 and 2.5 times in STZ-0E and STZ-40E groups than that of control. Plasma cortisol levels were higher STZ-0E and STZ-40E groups compared with those of control, but cortisol levels were lower significantly in STZ-400E group compared with those of the STZ-0E and the STZ-40E groups. The plasma insulin levels were lower in all three STZ-diabetic group compared with that of control, but were not affected by the level of dietary vitamin E. The metallothionein (MT) contents in liver, kidney and small intestine were five times higher in STZ-0E, STZ-40E and STZ-400E compared with that of control, but STZ-400E group was lower in the MT contents in tissues compared with that of STZ-40E group. Zn-MT peak in STZ-diabetic rats liver increased than that of control by Sephadex G-75, and Zn-MT peak divided into MTI and MTII peaks by DEAE Sephadex A-25 column chromatography. The present results indicate that STZ-induced diabetic rats are more sensitive to oxidative stress, leading to the acceleration of lipid peroxidation process, which can be more promoted low level of dietary vitamin E. And the result may that increase synthesis of MT induced in the liver of diabetic rats increased so it can be sure that the diabetes is one of the MT induce factor by free radical generation. And high vitamin E supplementation reduced total MT contents of liver, kidney and small intestine and the peak of purified Zn-MT. Through the results of these experiments, we can conclude that MT might be the free radical scavenger.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.597-607
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• 1996

This study has been investigated the potenial of increased dietary cysteine to alter the effects of cadmium and lead on tissure and bone metal concentrations, excretion and tissue metallothionein(MT) concentrations. Fifty-four male rats of Sprgue-Dawley strain weighing 149$\pm$17g were divided into 9 groups according to body weight. Nine experimental diets with different cadmium (0ppm, 400ppm), lead(0ppm, 710ppm) and cysteine (0.06%, 0.45%, 0.90%) levels were given to rats for 30 days ; Food intake, weight gain, F.E.R, and weights of liver, kidney and femur were decreased in cadmium supplied groups than in cadmium free groups. Urinary and fecal cadmium excretions were increased and MT synthesis we induced in liver, kidney and small intestine in cadmium supplied groups. In lead supplied groups, weight gain and F.E.R were decreased. With cysteine supplementation in cadmium supplied groups, weight gain and F.E.R, and weights of liver, kidney and femur were increased. Cadmium excretion in feces and MT concentrations in liver and kidney were also increased with cysteine supplementation. In lead supplied groups, there was no significant increase in food intake, weight gain and F.E.R with cysteine supplementation. Lead excretion in feces was increased in cysteine supplemented groups. In conclusion, effect of cadmium administration was more toxic than lead adminstration. Cysteine alleviated cadmium and lead toxicity by increasing metallothionein concentration and fecal excretions of heavy metals. Especially, effect of cysteine supplementation was more effective in cadmium groups than in lead groups. Effect of cysteine supplementation was not different with level of cysteine supplementation in both cadmium and lead groups.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.455-463
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• 2011

Metallothioneins are a class of small cysteine-rich proteins that have been associated with increased tolerance to metal and oxidative stresses in animals, plants, and fungi. We investigated a metallothionein-like (mt-like) gene shown previously to be upregulated in fruiting bodies of the fungus Agaricus bisporus in response to post-harvest storage. Analysis of an A. bisporus genomic DNA cosmid library identified two similar mt-like genes (met1 and met2) arranged as a bidirectional gene pair transcribed from the same promoter region. The promoter contained regulatory elements including 9 metal responsive elements and a CAAT box region 220 bp downstream of met1 that showed striking similarity to a feature in Coprinopsis cinerea mt-like gene promoters. Transcriptional analysis showed that both met genes are significantly and rapidly (within 3 hours) upregulated during post-harvest storage and expression is significantly greater in stipe and cap tissues compared with the gills. However, a strong directionality of the promoter was demonstrated, as transcript levels of met1 were at least two orders of magnitude greater than those of met2 in all samples tested.

• Journal of Environmental Health Sciences
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• v.18 no.1
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• pp.95-104
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• 1992

The influence of selenium to several toxic effects of cadmum, including lethality has been shown following pretreatment with cadmium, zinc and seleniurm Five groups of rats, each consisting of 16 rats, were studied and each group was divided into four subgroups, 4 rats for each subgroup. After subcutaneous pretreatment during 5 days with saline, CdCl$_{2}$ (0.5mg/kg, ZnCl$_{2}$ (13.0mg/kg) and $Na_{2}SeO_{3}$(1.0mg/kg), rats were given intraperitioneal administration of various dosage of or cadium of cadmium and selenium. After giving the challenge dose, cadmium and metallothionein(MT) concentrations were determined in liver and kidney The concentration of cadmium in liver and kideny increased proportionally to the increase of challenge dosage. The simultaneous administration of cadmium and selenium significantly more decrease cadmium concentrations in liver and kidney than those of the administration of cadmium only. However, MT concentrations in liver and kideny were increased by the pretreatment of cacmium, zinc and selenium. Our results suggest that increasing cadmium concentrations, gradully accumulating in the tissues of liver and kidney as a result of the pretreatment, served to induced the synthesis of MT, thus making them resistant to the challenge from cadmium.

• Applied Microscopy
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• v.34 no.3
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• pp.171-178
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• 2004

Metallothionein (MT) is a family of ubiquitous, low molecular weight (6-7 kDa), cysteine-rich protein with a high affinity to metal ions and has no aromatic amino acids and histidine. Some of the known functions of MT include detoxification of heavy metals and alkylating agents and neutralization of free radicals. Also, this protein may affect a number of cellular processes including gene expression, apoptosis, proliferation and differentiation. But, its actual functions are still not clear. The present study was undertaken to examine immunocytochemically the localization of MT in developing rat liver. On the day 11 of gestation, the fetal rat liver has already been formed and contained numerous oval cells with high nuclear cytoplasmic ratio, which were the progenitors of hepatic parenchymal cells, but no reaction products of MT were detected at this time. And then, positive reactions against MT started to appear predominantly in the parenchymal cells of liver from the 13th day after gestation. Reaction products, immunogold particles or brown coloration, were localized at both the nucleus and the cytoplasm of the parenchymal cells, except mitochondria. The intensity of this reaction gradually increased, and exhibited the strongest at birth. The intensity of MT staining and immunogold labelling diminished with growth, and by the 15th day after birth weak positive reaction was observed in the cells. In brief, positive reactions for MT were observed in the oval cells and the parenchymal cells during fetal stage, meanwhile they were present only in the parenchymal cells after birth. The present results suggest that MT possibly involves parechymal cell proliferation and differentiation through the storage or the supply of various metal ions in the developing rat liver.