• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.70-77
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• 1999

An extremely cadmium-tolerant budding yeast, Hansenula anomala B-7 underwent a morphological switch in response to either heat shock treatment or cadmium stress, respectively. It exhibited a morphological transition from a unicellular yeast form to a pseudohyphae-like coagulation when subjected to prolonged heat shock treatment. In contrast, the yeast cells showed an irregularity in surface morphology when given thermal stress for a short time. Patterns of proteins expressed in the pseudohyphae-like cells demonstrated that several proteins were overexpressed while others were underexpressed in comparison with those prepared from the cells in the yeast form. It was a striking feature, however, that nearly 40％ of the proteins extracted from the cells in the pseudohyphae form appeared to be composed of a single polypeptide. This polypeptide was apparently overexpressed during the pseudohyphae phase and its molecular weight was estimated to be 58 kDa according to SDS-PAGE analysis. However, a significant level of the protein was not observed in the cells before transition to pseudohyphae. The architecture of the cell shape was also damaged when incubated in a medium containing more than 1,000 ppm (8.9mM) of cadmium ions, although able to proliferate at a slow rate. However, the irregularity in the cell morphology exerted either by the brief heat shock treatment or by the cadmium stress with the high concentrations of the metal ions was not repaired, even though the damaged cells were allowed to grow for sufficient time in fresh, cadmium-free medium.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.93-100
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• 2008

For investigation of adsoption properties of cadmium elimination by wood charcoal, $25m{\ell}$ aqueous cadmium solutions in various concentrations were treated with 0.2 g wood charcoal of Red Oak (Quercus mongolica) for 280 minutes. Almost 100% of cadmium elimination ratio was obtained in the solutions with initial concentration of 20 and 40 ppm in the treatment, whereas they were 75 and 50% in those of 80 and 160 ppm. In the effect of treatment time, the highest amount of cadmium ions was eliminated during the first ten minutes in each solution so that the elimination ratio of each case was over 70% of the maximum elimination value. From the analysis of adsorptive cadmium adsorption mechanism using the Langmuir adsorption isotherm, it was suggested that cadmium ion molecules were adsorbed at the active sites on the charcoal particle in form of one layer. The Gibbs free energy of the adsorption process was calculated in negative value for each solution. This means the adsorption processes are spontaneous which do not require the extra input energy.

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.453-457
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• 1993

Cadmium(II) complexation by a well characterized soil fulvic acid (FA) from the Okchun Metamorphic Belt were studied at pH of 6.0 in 0.1 M $NaClO_4$ using the ultrafiltration technique. The conditional stability constants thus obtained were log K= 3.90${\pm}$0.15 and 3.99${\pm}$0.12 $L{\cdot}mol^{-1}$ at fulvic acid concentrations of 101 and 226 mg${\cdot}L^{-1}$ respectively. When free cadmium ion concentration was measured directly using an ion selective electrode, log K of 4.12${\pm}$0.03 $L{\cdot}mol^{-1}$ was obtained. These results show that fulvic acid forms predominately 1 : 1 complex with $Cd^{2+}$ ions. The maximum binding ability of this polyelectrolyte material was 0.886 mmol Cd/g FA. The average gram formula weight of fulvic acid was estimated to be 1130 daltons.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.159-164
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• 2021

Heavy metals exist in soils in various chemical forms including free metal ions and organo-metal complexes. The ratio of free metal ions has been known to be highly associated with the plant absorption of heavy metals. This study aims to understand the effect of free ions and organo-metal complexes on the absorption of lead (Pb) and cadmium (Cd) by plants. For this, lettuce grown in a hydroponic system for 28 days was consequently grown another 48 hours using Pb and Cd solutions. The ratios of free ion to organo-metal complexes in the solutions were adjusted at 100:0, 90:10, 70:30, 60:40 by four different organic acids (citric, oxalic, acetic, and humic acid). After that, the concentration of Pb and Cd in lettuce were analyzed. The Pb and Cd absorption by lettuce was more relied on the types of organic acids treated and the type of metals rather than the ratio of free metal ions. For example, citric acid increased the Pb absorption while it decreased the Cd absorption by lettuce. There was no significant relationship between free metal ion ratios and both Pb and Cd uptake by lettuce. It could be explained that citric acid, a relatively higher molecular weight organic acid, has higher ion binding capacity, so it forms organo-Pb complex easily due to the higher affinity of Pb on the binding site in comparison with Cd. Consequently, this complexation would assist Pb uptake by lettuce.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.04a
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• pp.1-19
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• 2003

The electronic market thrust for many hybrid circuit manufacturers is changing because commercial market segments such as telecommunications, automotive and consumer electronics have increased the demand world wide for environmentally friendly thick film products. This, in turn, places a stronger emphasis on the material suppliers within the circuit fabrication industry to provide toxin free products with equal or higher performance than traditional technology. A new group of silver based thick film conductors, which are totally free of such toxins as cadmium, nickel and Bead have been developed to meet new environmental requirements. Traditional thick film products and newly developed toxin free compositions will be compared and data will be presented. To evaluate their performance, both groups of conductors were tested for solder acceptance, leach resistance and aged adhesion with standard lead-containing solder and higher temperature lead-free solder.

• Journal of Nutrition and Health
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• v.32 no.4
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• pp.353-368
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• 1999

This study was performed to investigate the effects of Korean native plant diets on lipid and cadmium (Cd) metabolisms and also antioxidative enzyme activities in rats. Seventy male Sprague-Dawley rats weighing 210.3$\pm$2.7g were blocked into ten groups according to body weight. Rats were raised for four weeks with diets containing 0 or 0.04%(w/w) cadmium chloride and 5%(w/w) plant powder-Ssook(Artemisia princeps var. orientalis HARA), Chamchwi(Aster scaber THUNB), Gomchwi(Lingularia fischeri TUBCZ). or Solbeerum (Portulaca oleracea LINNE). Food intake, weight gain, food efficiency ratio, and weights of liver, kidney, spleen and epididymal fat were significantly lower in Cd-exposed groups, food efficiency ratio, and weights of liver, kidney, spleen and epididymal fat were significanlty lower in Cd-exposed groups. Plasma total lipid level, liver total lipid, cholesterol and triglycerde concentrations, and fecal total lipid, cholesterol and triglyceride excretions were decreased by Cd administration. Total lipid and triglyceride concentration in plasma and liver were lower in Chamchwi groups together with increased fecal total lipid and triglyceride excretions. Cholesterol concentration in plasma and liver were lower in Gomchwi groups with increased fecal cholesterol excretions. Activities of red-blood-cell superoxide dismutase(SOD), and liver catalase, SOD and glutathione peroxidase (GSH-px) were decreased significantly by Cd administration. Thiobarbituric acid reactive substance(TBARS) concentrations of plasma and liver were increased by Cd administration. Thiobarbituric acid reactive substance(TBARS) concentration of plasma and liver were increased by Cd administration. Administration of plant diets decreased plasma and liver catalase, SOD and GSH-px activities in Cd-free diet groups and increased them in Cd-administered groups. Plasma and liver TBARS concentrations were decreased in animals fed plant diets, with Chamchwi showing the most effective antioxidative capacity. The concentration of Cd accumulated in blood and tissue decreased in Cd-exposed groups fed plant diets. Liver Cd concentration were lower in the Chamchwi and Gomchwi groups, and kidney Cd levels were lower in the Ssook and Chamchwi groups. Among them, Chamchwi was the most effective in Cd detoxification. In conclusion, Chamchwi and Gomchwi were effective in lowering tissue lipid levels, with Chamchwi having the greatest antioxidative and detoxifying effects.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.220-220
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• 2018

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.33-33
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• 2018

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.5
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• pp.513-519
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• 1999

Direct exposure of renal tubular brush-border membranes (BBM) to free cadmium (Cd) causes a reduction in phosphate (Pi) transport capacity. Biochemical mechanism of this reduction was investigated in the present study. Renal proximal tubular brush-border membrane vesicles (BBMV) were isolated from rabbit kidney outer cortex by Mg precipitation method. Vesicles were exposed to $50{\sim}200\;{\mu}M\;CdCl_2$ for 30 min, then the phosphate transporter activity was determined. The range of Cd concentration employed in this study was comparable to that of the unbound Cd documented in renal cortical tissues of Cd-exposed animals at the time of onset of renal dysfunction. The rate of sodium-dependent phosphate transport $(Na^+-Pi\;cotransport)$ by BBMV was determined by $^{32}P-Iabeled$ inorganic phosphate uptake, and the number of $Na^+-Pi$ cotransporters in the BBM was assessed by Pi-protectable $^{14}C-labeled$ phosphonoformic acid $([^{14}C]PFA)$ binding. The exposure of BBMV to Cd decreased the $Na^+-Pi$ cotransport activity in proportion to the Cd concentration in the preincubation medium, but it showed no apparent effect on the Pi-protectable PFA binding. These results indicate that an interaction of renal BBM with free Cd induces a reduction in $Na^+-Pi$ cotransport activity without altering the carrier density in the membrane. This, in turn, suggest that the suppression of phosphate transport capacity $(V_{max})$ observed in Cd-treated renal BBM is due to a reduction in $Na^+-Pi$ translocation by existing carriers, possibly by Cd-induced fall in membrane fluidity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.725-730
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• 1994

This study was conducted to investigate the effect of dietary zinc (Zn) and/or cadmium (Cd) on hepatic microsomal and cytosol enzyme activities. Male Spraque-Dawley rats (110$\pm$10g ) received zinc (0, 30 and 300 ppm/) and Cd-treated groups were administered oral intubation with Cd chloride (5.0mg/kg of body weight 0 at the same time once a week. The effect of Cd on the activity of hepatic cytochromep-450 , xanthine oxidase(X. O) and superoxide dismutase (SOd) was studied in rats. Cd oral intubation resulted in a decrease in cytochrome P-450 content and SOD activity whereas a significant increase in the X.O. activity was observed was observed . Intake of excessive Zn led to an increased activity of microsomal alcohol dehydrogenase (ADH) , whereas Zn deficiency group led to a decreased group. The mechanism by which Zn induces the decreasing of Cd toxicity in rats, seems to rely on the protection of the enzyme systems P-450, ADH, aldehyde dehydrogenase (ALDH) and X.O. in the liver, possibly by forming non-toxic Cd metallothionein. These results indicate that Zn and Cd regulation might occur via inhibitory protein component of the $H_2O$$_2$ -generator system.