• 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 Mineralogical Society of Korea
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• v.28 no.2
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• pp.173-185
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• 2015

Janggun mine (longitude $129^{\circ}$ 03'38.91" Latitude $36^{\circ}$ 51'31.59") had been operated as an underground mine for last few decades. As the part of the remediation process, the surface of tailing dump was covered with uncontaminated soil about 20 cm in depth and acacia trees were planted. Heavy metal uptake of acacia from tailing soil has continued for the past 15 years. Heavy metal concentration ranges of tailing soil that contaminated with As (66.43-9325.34 mg/kg), Cd (0.96-1.09 mg/kg), Cu (16.90-57.60 mg/kg), Pb (57.33-945.67 mg/kg), and Zn (154.48-278.61 mg/kg) have higher than those of control soil As (38.98 mg/kg), Cd (0.42 mg/kg), Cu (10.26 mg/kg), Pb (8.21 mg/kg), Zn (46.74 mg/kg). The As, Cd, Cu, Pb and Zn concentrations of leaf of acacia in highly contaminated tailing dump were 165.95, 0.04, 10.68, 3.18, 48.11 mg/kg, respectively. The metal contents of leaf of acacia tree that obtained from uncontaminated control soil are 1.31 of As, 3.90 of Cu, 0.22 of Pb and 11.01 mg/kg of Zn. It was investigated that in the acacia tree, heavy metals such as As, Cu, Pb and Zn tend to be more highly concentrated in bark and leaf, compared with sapwood and heartwood.

• Environmental Analysis Health and Toxicology
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• v.19 no.4
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• pp.359-366
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• 2004

Iron (Fe) is an essential metal in biological processes, which maintains a homeostasis in the human body. Divalent metal transporter 1 (DMT1) has been known as an iron transporting membrane protein, which is involved in the uptake Fe at the apical portion of intestinal epithelium, and may transport Fe across the membrane of acidified endosome in peripheral tissues. In this study, we studied the tissue distribution of DMT1 in the Fe supplemented (FeS) diet fed rats, and the regulation of DMT1 expression by depleting body Fe. Sprague-Dawley rats were divided into two groups, and fed FeS (120 mg Fe/kg) diet or Fe deficient (FeD, 2∼6 mg Fe/kg) diet for 4 weeks. The evaluation of body Fe status was monitored by measuring sFe, UIBC and tissue Fe concentration. Additionally, DMT1 mRNA levels were analyzed in the peripheral tissues by using the quantitative real time RT-PCR method. In the FeS diet fed rats, the tissue Fe was maintained at a relatively high level, and DMT1 was eventually expressed in all tissues studied. DMT1 was highly expressed in the testis, kidney and spleen, while a moderate levels of DMT1 expression was detected in the brain, liver and heart. In the digestive system, the highest level of DMT1 was found in the duodenum. Feeding the FeD diet caused a reduced body weight gain and depletion of body Fe with finding of decreased sFe, increased UIBC and decreased tissue Fe concentration. The depletion of body Fe upregulated DMT1 expression in the peripheral tissue. The expression of DMT1 was very sensitive to the body Fe depletion in the small intestine, especially in the duodenum, showing dramatically higher levels in the FeD rats than those of the FeS group. In the FeD diet fed animals, the expression of DMT1 was low significantly in other tissues compared with the duodenum. The expression of DMT1, however, was 60∼120% higher in the testis, kidney and spleen, and 30∼50% higher in the lung, liver and heart, compared to the FeS diet fed rats. In summary, DMT1 expression was ubiquitous in mammalian tissue, and the level of expression was the organ-dependent. The expression of DMT1 in peripheral tissues was upregulated by depletion of body Fe. Duodenum was the most sensitive tissue among organs studied during Fe depletion, and expressed the greatest level of DMT1, while other tissues were less higher than in duodenum. This study supports that DMT1 plays a role in maintaining the body Fe level through intestinal uptake as well as homeostasis of Fe in the peripheral tissue.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.171-178
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• 2013

BACKGROUND: Consensus of heavy metal phytoavailability in soils needs to be introduced for soil management protocols in relation to safer food production in the contaminated agricultural soils. For this, setting up the method for evaluation of metal phytoavailability in soil is an essential prerequisite. METHODS AND RESULTS: The current study was carried to select a proper single extraction method for determination of phytoavailable metal concentration in soil. Two extraction methods were examined including 1 M $NH_4NO_3$ extraction and 0.01 M $Ca(NO_3)_2$ extraction methods using 142 soil samples collected from the agricultural soils nearby abandoned mining area in Korea. Corelation analysis was conducted between phytoavailable metal concentrations and soil properties potentially influencing on the metal phytoavailability. Both methods showed similar significance (p<0.001) in correlation with soil properties such as soil pH. However, higher correlation coefficients between phytoavailable metal concentrations and soil properties were observed when used $Ca(NO_3)_2$ extraction rather than using $NH_4NO_3$ extraction. CONCLUSION(S): It appeared that 0.01 M $Ca(NO_3)_2$ extraction was better option for determination of phytoavailable metals in soils and further study to test the efficiency of this method is required in combination with plant uptake.

• Advances in environmental research
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• v.3 no.1
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• pp.71-86
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• 2014

Macronutrients ($Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$), yield and yield components, bioaccumulation and translocation of metal in plant parts of three Vigna species (V. cylindrica, V. mungo, V. radiata) were evaluated at 0, 50, 100 and $150mgkg^{-1}$ soil of Nickel (Ni). A marked inhibition (p < 0.001) in the distribution of various macronutrients was noticed in these Vigna species except for $Mg^{2+}$ content of the shoot and leaves. Similarly, all species retained more $Ca^{2+}$ in their roots (p < 0.05) as compared to the aerial tissues. Ni induced a drastic decline (p < 0.001) for various yield and yield attributes except for 100 seed weight. Toxicity and accumulation of Ni in plant tissues considerably increased in a concentration dependent manner. Vigna species signify an exclusion approach for Ni tolerance as both bioaccumulation factor (BF) and translocation factor (TF) were less than 1.0. The Ni content of plants being root > shoot > leaves > seeds. Scoring for percentage stimulation and inhibition (respective to control) at varying levels of Ni revealed tolerance of the species in an order of V. radiata > V. cylindrica > V. mungo. The acquisition of Ni tolerance in V. radiata seems to occur through an integrated mechanism of metal tolerance that includes sustainable macronutrients uptake, stronger roots due to greater deposition of $Ca^{2+}$in the roots, restricted transfer of Ni to above ground tissues and seeds as well as exclusion capacity of the roots to bind appreciable amount of metal to them. Thus, metal tolerant potential of V. radiata could be of great significance to remediate metal contaminated soil owing lesser impact of Ni on macro-nutrients, hence the yield.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.246-246
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• 2006

Ionic polymer-metal composite (IPMC) soaked with various ionic liquids was prepared by using polystyrene sulfonic acid-grafted poly(vinylidene fluoride-co-hexafluoropropylene) as ion-exchange membrane (IEM). The prepared IPMCs were effectively deformed three times larger and actuated for 300 times longer than those of Nafion with water at the same applied conditions. The experimental results indicated than the increase in the bending capability can be caused by the increase in the improved properties of the IEMs and ionic liquids such as uptake content and ionic conductivity. And air-operating stability of the IPMCs is appreciably governed by various physical and electrochemical properties of soaked solvents in IEMs.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.72-75
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• 2003

Plant species have shown the capability to absorb U into the biomass. Norman(l952) even suggested that uranyl ion acts as an accessory microelement in growth of Lemna and flax roots. The plants, termed metal hyperaccumulators, can extract and accumulate more than 1000-10,000mg heavy metal per kilogram of dry weight of plants (0.1-1%). The most vital main factors influencing the ability and efficiency of phytoremediation is the ability of the plant to uptake the metals from soil before the accumulation mechanism happens in the plant tissue. (omitted)

• Polymer(Korea)
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• v.29 no.5
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• pp.463-467
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• 2005

In order to enhance the actuation force of ionic polymer-metal composite (IPMC) made with the acrylic copolymer of fluoroalkyl methacryate, acrylic acie, and 2-hydroxyethyl methacrylate(HEMA), the hydroxy group of HEMA was corsslinked with 1,3-diethoxy-1,1,3,3-tetramethyldisiloxane. The water uptake was reduced and the mechanical strengths and the actuation force of the membrane was improved by crosslinking. However, current and deformation responses of IPMC were decreased by crosslinking.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.253-262
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• 1995

The heavy metal contents of soils which had been contaminated with mine residues and green onion and lettuce which were grown on these soils were analyzed. The results obtained are summarized as follows: 1. Heavy metal contents in the soil where green onion and lettuce died back or were poor in growth were unusually high. 2. Heavy metal contents in the plants grown in the soil of high level of metals were also high, in the order of root > leaf > stem. In case of Mn, however, the content was the highest in the leaf. 3. Contents of Cd, Cu, Zn and Ni in soil were positively correlated with those in plant. In case of Pb, there was no consistent relationship between the contents in soil and plant. 4. Even in the soils where plant growth appeared to be normal the heavy metal contents both in soil and in plant were higher than the national average.

• Environmental Analysis Health and Toxicology
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• v.19 no.2
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• pp.191-200
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• 2004

Zinc (Zn) is an essential element in biological process, however inadequate Zn status in general population have been recognized. To update the knowledge for Zn-cadmium (Cd) interaction, we studied the intestinal uptake and transport, and the expression of metal transporter proteins (divalent metal transporter 1, DMT1 ; metal transporter protein 1, MTP1 ; zinc transporter 1, ZnTl ; metallothionein 1 , MT1) in duodenum after Cd exposure using Zn deficient animal model. Rats were led Zn deficient (ZnD, 0.5-1.0 mgZn/kg) or Zn supplemented (ZnS, 50mg Zn/kg) diet for 4 weeks, and followed single administration of $^{109}$ CdCl$_2$orally. The body Zn flatus and tissue Cd concentration were determined at 24 hrs after Cd administration. Total body burden of Cd and Cd absorption index (AI, %) were estimated based on the tissue Cd analyzed. DMT1, MTP1, ZnTl and MT1 mRNA were analyzed by using RT-PCR method. Feeding of Zn deficient diet for 4 weeks produced a reduced body weight gain and a depletion of body Zn. Tissue Cd concentration, body burden of Cd and Cd absorption index were higher in the ZnD diet fed rats than the ZnS diet red rats. Especially, Cd concentration in the small intestine (duodenum, jejunum and ileum) and the colon of FeD diet fed rats were higher markedly than in the FeS diet group. The expression levels of DMT1, MTP1 and ZnT1 mRNA in FeD diet fed rats were similar to the FeS diet. The level of MT1 mRNA expression was significantly lower in the FeD than the FeS diet fed rats. Taken together, theses results indicate that Zn deficiency in diet induce an increased intestinal absorption and tissue retention of Cd, and down -regulate the MT1 expression in the intestine which might be play a part of role in Cd absorption and transport in mammalian. These findings suggest that deficiency of essential metal could be enhanced the toxicity of toxic, non-esstial metals through the metal-metal interaction.