• Bulletin of the Korean Chemical Society
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• v.22 no.5
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• pp.514-518
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• 2001

We have explored the importance of two ATP binding domains of Hsp104 protein in protection of yeast cells from cadmium exposure. In the previous study we have discovered that the presence of two ATP binding sites was essential in providing heat sh ock protection as well as rescuing cells from oxidative stress. In this paper we first report wild type cell with functional hsp104 gene is more resistant to cadmium stress than hsp104-deleted mutant cell, judging from decrease in survival rates as a result of cadmium exposure. In order to demonstrate functional role of two ATP binding sites in cadmium defense, we have transformed both wild type (SP1) and hyperactivated ras mutant (IR2.5) strains with several plasmids differing in the presence of ATP binding sites. When an extra copy of functional hsp104 gene with both ATP binding sites was overexpressed with GPD-promoter, cells showed increased survival rate against cadmium stress than mutants with ATP binding sites changed. The degree of protection in the presence of two ATP binding sites was similarly observed in ira2-deleted hyperactivated ras mutant, which was more sensitive to oxidative stress than wild type cell. We have concluded that the greater sensitivity to cadmium stress in the absence of two ATP binding sites is attributed to the higher concentration of reactive oxygen species (ROS) produced by cadmium exposure based on the fluorescence tests. These findings, taken all together, imply that the mechanism by which cadmium put forth toxic effects may be closely associated with the oxidative stress, which is regulated independently of the Ras-cAMP pathway. Our study provides a better understanding of cadmium defense itself and cross-talks between oxidative stress and metal stress, which can be applied to control human diseases due to similar toxic environments.

• Journal of Ecology and Environment
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• v.30 no.3
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• pp.257-264
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• 2007

Over-expression of a copper/zinc superoxide dismutase (Cu/ZnSOD) resulted in substantially increased tolerance to cadmium exposure in Arabidopsis thaliana. Lower lipid peroxidation and $H_2O_2$ accumulation and the higher activities of $H_2O_2$ scavenging enzymes, including catalase (CAT) and ascorbate peroxidase (APX) in transformants (CuZnSOD-tr) compared to untransformed controls (wt) indicated that oxidative stress was the key factor in cadmium tolerance. Although progressive reductions in the dark-adapted photochemical efficiency (Fv/Fm) and quantum efficiency yield were observed with increasing cadmium levels, the chlorophyll fluorescence parameters were less marked in CuZnSOD-tr than in wi. These observations indicate that oxidative stress in the photosynthetic apparatus is a principal cause of Cd-induced phytotoxicity, and that Cu/ZnSOD plays a critical role in protection against Cd-induced oxidative stress.

• Molecular & Cellular Toxicology
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• v.2 no.1
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• pp.54-59
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• 2006

The toxicity of cadmium on Caenorhabditis elegans was investigated to identify sensitive biomarkers for environmental monitoring and risk assessment. Stress-related gene expression were estimated as toxic endpoints Cadmium exposure led to an increase in the expression of most of the genes tested. The degree of increase was more significant in heat shock protein-16.1, metallothionein-2, cytochrome p450 family protein 35A2, glutathione S-transferase-4, superoxide dismutase-1, catalase-2, C. elegans p53-like protein-1, and apoptosis enhancer-1 than in other genes. The overall results indicate that the stress-related gene expressions of C. elegans have considerable potential as sensitive biomarkers for cadmium toxicity monitoring and risk assessment.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.30-35
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• 1994

A varient strain of budding yeast, Hansenula anomala B-7 which had been identified to be highly resistant to cadmium ions, were observed by transmission electron microscopy. It was shown that the cells accumulated excess amounts of cadmium ions throughout inside the cell rather than on the cell surface. The cell growth in response to cadmium or heat shock stress has also been investigated. It was observed that the cells precultured in the presence of 500 $\mu$ g/ml of Cd ions grew slower than those precultured at 1, 000 $\mu$ g/ml of the metal ions, when they were cultivated in the media containing 1, 000 $\mu$g/ml of the metal ions. Heat shock, however, stimulated the cell growth transiently, when the cells were allowed to grow in the presence of 1, 000 $\mu$g/ml of the metal ions. But the cells given heat shock for more than 100 min received permanent damage to growth. Effects of both stresses on budding rate was also examined. It revealed that the stresses did not change the budding ratio much, which was contradictory to that observed from the same budding yeast, Saccharomyces cerevisiae. Furthermore, the cells treated with 1, 000 $\mu$g/ml of the metal ions not only induced, but also switched off the expression of several new proteins. Some of the cadmium stress-inducible proteins were estimated to be also induced by heat shock stress.

• Toxicological Research
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• v.35 no.1
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• pp.25-35
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• 2019

The extracts of Plathymenia reticulata and Connarus favosus are widely used in the folk medicine. The potential protective effects of these extracts have been evaluated against cadmium in the yeast Saccharomyces cerevisiae, and against mercurial contamination in zebrafish Danio rerio. In yeast, both extracts efficiently protected the ${\Delta}ycf1$ mutant strain exposed to cadmium chloride restoring the growth, the expression of stress-response genes and decreasing the level of oxidative stress. In zebrafish, the supplementation of methylmercury-contaminated diet with both plant extracts similarly protected fish through the suppression of the methylmercury-induced lipid peroxidation, decrease of acetylcholinesterase activity, and restoring the expression levels of stress-response genes. This study particularly demonstrates the protective potential of both aqueous extracts against methylmercury, and could represent an interesting alternative for the Amazonian fish-eating communities to cope with the impact of chronic exposure to contaminated diets.

• 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.

• Environmental Analysis Health and Toxicology
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• v.19 no.3
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• pp.279-286
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• 2004

Although numerous studies have shown that cadmium disturbs the normal biological processes in central nervous system, the mechanism of toxicity is not well understood. The present study has investigated the effect of cadmium on oxidative stress, Na$^{+}$K$^{+}$ ATPase activity and the aggregation of amyloid beta peptide ($\beta$-amyloid) in neuronal cell line, HT22 cell. LC$_{5}$ and LC$_{50}$ of cadmium for HT22 cell resulted from MTT assay was 4.1 uM and 9.5 uM, respectively. Cadmium (2 to 8 uM) dose-dependently increased the lipid peroxidation and decreased the content of glutathione. Cadmium 4 uM showed a significant decrease in Na$^{+}$/K $^{+}$ ATPase activity as compared with control group. The aggregation of $\beta$-amyloid was accelerated in a dose-dependent manner by the treatment with 2 to 8 uM cadmium. These results suggest that the neurotoxicity of cadmium can be mediated by the increase in oxidative stress and decrease in Na$^{+}$/K$^{+}$ ATPase activity.se activity.

• Toxicological Research
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• v.14 no.4
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• pp.577-585
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• 1998

Cadmium is an important industrial and environmental pollutant and has adverse effects on cell growth and metabolism, although the mechanisms of its cellular toxicity are still unclear. This study was performed to elucidate the cytotoxic mechanism of cadmium in the viewpoint of oxidative stress and cytoskeleton alterations in WB-F344 rat liver epithelial cells. 200 $\mu\textrm{M}$ $CdCl_2$ caused a severe disassembling of microtubule and micro filament and an apparent cell retraction under an observation with fluorescence micoscope. (equation omitted)-tubulin and F-actin protein were highly thiolated at 20 min and then disappeared from 1 hour after the treatment of 200 $\mu$M CdCl$_2$in the immunoblot analysis. Intracellular GSH was decreased from 1hr to 24 hrs by 66.6 or 200 $\mu\textrm{M}$ of $CdCl_2$. Intracellular protein thiol was also decreased by 22.2, 66.6 and 200 $\mu\textrm{M}$ of $CdCl_2$ at 1 hour after its treatment. The product of lipid peroxidation (malondialdehyde) was increased from 4 hrs by 66.6 and 200$\mu\textrm{M}$ of $CdCl_2$. These data indicate that cadmium induces oxidative stress involving disassembling of microtubule and micro filament, thiolation of (equation omitted)-tubulin and actin protein, depletion of GSH and protein thiol, and increase of lipid peroxidation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.3
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• pp.264-268
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• 2015

The present research investigated copper and cadmium stress-induced differentially expressed genes (DEGs) using annealing control primers (ACP) with the differential display reverse transcription polymerase chain reaction technique in alfalfa (Medicago sativa L. cv. Vernal) leaves. Alfalfa leaves were subjected to $250{\mu}M$ of copper and cadmium treatment for a period of 6 h. A total of 120 ACPs was used. During copper and cadmium treatment, 6 DEGs were found to be up or down regulated. During copper stress treatment, 1 DEG was up-regulated, and 3 novel genes were discovered. Similarly, during cadmium stress treatment, 1 DEG was up-regulated and 5 novel genes were identified. Among all 6 DEGs, DEG-4 was identified as the gene for trans-2,3-enoyl-CoA reductase, DEG-5 was identified as the gene for senescence-associated protein DIN1 and DEG-6 was identified for caffeic acid O-methyltransferase. All the up-regulated genes may play a role in copper and cadmium stress tolerance in alfalfa.

• Molecules and Cells
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• v.19 no.1
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• pp.81-87
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• 2005

Phytochelatins play an important role in heavy metal detoxification in plants as well as in other organisms. The Arabidopsis thaliana mutant cad1-3 does not produce detectable levels of phytochelatins in response to cadmium stress. The hypersensitivity of cad1-3 to cadmium stress is attributed to a mutation in the phytochelatin synthase 1 (AtPCS1) gene. However, A. thaliana also contains a functional phytochelatin synthase 2 (AtPCS2). In this study, we investigated why the cad1-3 mutant is hypersensitive to cadmium stress despite the presence of AtPCS2. Northern and Western blot analyses showed that expression of AtPCS2 is weak compared to AtPCS1 in both roots and shoots of transgenic Arabidopsis. The lower level of AtPCS2 expression was confirmed by RT-PCR analysis of wild type Arabidopsis. Moreover, no tissue-specific expression of AtPCS2 was observed. Even when AtPCS2 was under the control of the AtPCS1 promoter or of the cauliflower mosaic virus 35S promoter (CaMV 35S) it was not capable of fully complementing the cad1-3 mutant for cadmium resistance.