• Korean Journal of Ichthyology
• /
• v.23 no.1
• /
• pp.61-69
• /
• 2011

Gene and promoter structures of metallothionein(MT) from Miho spine loach (Cobitis choii; Cypriniformes) were characterized, and the transcriptional responses to experimental exposures to heavy metals and heat stress were examined. The C. choii metallothionein displayed well-conserved features of teleostean metallothioneins at gDNA, mRNA and amino acid levels. Bioinformatic analysis predicted that the C. choii MT regulatory region potentially possessed various motifs or elements targeted by various transcription factors associated with metal-coordinating regulation (e.g., metal transcription factor-1), immune responses (e.g., nuclear factor kappa B), and thermal modulations (e.g., heat shock factor). Acute heavy-metal exposures to 0.5 or $1.0\;{\mu}M$ of cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni) or zinc (Zn) showed that MT transcription was significantly stimulated by Cd (9.6-fold relative to non-exposed control) and Cu (10.4-fold), only moderately by Mn (2.4-fold), but hardly by Ni and Zn. Elevation of water temperature from $25^{\circ}C$ to $31^{\circ}C$ caused a rapid modulation of MT mRNAs toward upregulation to 9.5-fold; however, afterward the elevated mRNA level slightly decreased during further incubation at $31^{\circ}C$ for 6 h. Results from this study suggest that MT-based expression assay could be a useful basis for better understanding the metal- and/or heat-caused stresses in this endangered fish species.

• Journal of Environmental Health Sciences
• /
• v.27 no.4
• /
• pp.115-122
• /
• 2001

The purpose of this study was to investigate the metallothionein of acute cadmium poisoning mice as a Cadmium index. Forty male ICR mice were injected with cadmium chloride solution from 1/8LD50 to 1/2LD50 dose. At 24 hours after exposed Cd, I examined Cd and metallothionein (MT) intissues(liver and kidney) and fluids(whole blood and urine) and also measured low molecular proteins, N-acetyl-D-glucosaminidase(NAG) and 2- microglobuline (2-MG) in urine. The concentration of Cd and MT of liver kidney whole blood and urine were increased with dose dependent manner. Urinary Cd and urinary MT and very good significance (p<0.01) and urinary MT had good significance with kidney Cd and NAG but not 2-MG Conclusionally MT in urine was very correlated with kidney Cd and urine Cd, So MT maybe useful as a Cd poisoning index.

• Environmental Analysis Health and Toxicology
• /
• v.18 no.1
• /
• pp.15-19
• /
• 2003

Metallothionein gene expression activity of cadmium was investigated in a human lung epithelial cell line. Cells, grown to near confluence, were exposed to 0∼10 ${\mu}$M Cd metal for 6 hours. Cadmium did not cause morphological alteration in lung epithelial cells that are characteristic of cell damages such as cell shrinkage, detachment of the cell from its neighbors, cytoplasmic and chromatic condensation. However, metallothionein genes of MT-1 and MT-2 were rapidly induced in the treated cell measured by RT-PCR. Regarding the induction pattern of motallothionein mRNA, MT-1 mRNA was induced in a dependent manner. MT-2 mRNA induction, which was measured using oligo primers based on cDNA of human reticulocytes, seemed to be slightly increased in low doses but decreased at high concentration used in the experiment.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.1
• /
• pp.59-64
• /
• 2004

Metallothionein gene expression of diesel exhaust particles (DEP) was investigated in human lung epithelial cell line. DEP was collected from diesel motor bus and soluble fraction in water was obtained. Cells, grown to near confluence, were exposed to 5-50 ppm DEP for 6 hours. Regarding the metallothionein gene expressions, MT-1 and MT-2 were induced in the DEP-treated cell by using RT-PCR and real-time PCR. However, MT-3 which is known to be brain specific, and another isoform MT-4 were not expressed in cadmium-treated groups as well as control group. Heavy metal of DEP was also analyzed and Zn was found as the major component of heavy metals in DEP used in this study.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.3
• /
• pp.261-269
• /
• 2004

Although the biological functions of metallothioneins (MTs) are still being investigated, they have been suggested to be involved in detoxification of heavy metals, scavenging of free radicals, and protection against alkylating agents. MTs have been reported to be induced in most of animal tissues by heavy metals such as zinc, copper, mercury and cadmium, and the proteins have binding affinities to the metals. However, the presence or induction of MTs was reported not to be clear in leydig cells, which produce testosterone for the maturation of spermatozoa in male testes. In this study, we investigated the inducibility of metallothionein isomers by cadmium in cultured mouse leydig cells. Total RNA was extracted from the near confluent grown leydig cells and RT-PCR was Performed using the Primers which were synthesized on the basis of MT-1, 2, 3 and 4 cDNA from GenBank database. As results, MT-1 and MT-2 mRNA were found to be expressed in cadmium non-treated control cells and MT 1 mRNA expression was dose-dependent when leydig cells were treated with cadmium chloride. But MT-3 which is known to be brain specific and MT-4 which is another isoform of metallothionein, were not expressed. Other genes induced or depressed in cadmium treated leydig cells were also identified by microarray techniques.

• Environmental Analysis Health and Toxicology
• /
• v.12 no.3_4
• /
• pp.15-22
• /
• 1997

This experiment was performed to examine the immuno-reactive characteristics of fish metal-binding protein, metallothionein (MT), and gain the practical understandings for the proposed use of fish MT as a biomarker. Liver MT induced by Cd in the silver carp was seperated and purified by gel filtration chromatography and ion exchange chromatography. The immuno-reactivity of fish MT was examined with 3 rabbit antisera. Fish MT showed little reactivity with rabbit anti-rat MT antiserum and a weak reactivity with anti-MT peptide antiserum while showed a strong reactivity with rabbit anti-fish MT antiserum. The time-course change of liver MT in the silver carp, after waterborne exposure to 1 ppm of Cd, was checked by Cd-hem method and established competitive ELISA. In both cases, the induction of liver MT showed a good increasing relationship with the exposure days. The results indicate that the fish MT can be developed as a useful biomonitoring means in the toxicological study and for the evaluation of water pollution.

• Environmental Analysis Health and Toxicology
• /
• v.11 no.1_2
• /
• pp.11-17
• /
• 1996

The purpose of this experiment is to estabilish the sensitive and specific ELISA (enzyme linked immunosorbent assay) system for the detection of fish metallothionein (MT). Silver carp were injected with CA of 1-8mg/kg body wt. 4 times during 10 days. Silver carp was very tolerant species to CA. Cd induced MT in liver was seperated and purified by gel filtration chromatography and ion exchange chromatography and identified by spectrophotometry, native gel electrophoresis and western blot analysis. The rabbit antiserum was produced by immunizing rabbit with lyophilized MT, and the competitive ELISA system was estabilished for the detection of fish MT. In the present ELISA system, the detection limit was about 33 ng/ml. When this ELISA system was employed to determine the MT level in the supernatant sample of fish liver homogenate, the reaction curve showed a good parallel corelationship with the calibration curve over a certain dilution range. The results indicate that the competitive ELISA can be a useful tool for the detection of fish MT in the toxicological study and the evaluation of water pollution.

• Animal cells and systems
• /
• v.5 no.3
• /
• pp.263-266
• /
• 2001

Metallothionein (MT) is induced in the regenerating rat liver. We have investigated expression of MT gene by RT PCR as well as specific localization of MT by immunocytochemistry in regenerating rat liver after partial hepatectomy (PH). MT mRNA level started to increase from 1 h and reached the peak at 8 h after PH. The level decreased gradually by 24 h, and became similar to that of control group. In the immunocytochemical study, in all groups treated with primary antibody, immunogold particles indicating the presence of MT were evenly distributed throughout both cytoplasm and nucleus of the rat hepatocytes. Within the nucleus, the gold particles appeared to be intensely localized in the areas of euchromatin and nucleolus. Within the cytoplasm, gold particles did not seem to adhere to mitochondria or Iysosomes, but were freely distributed. However, rough endoplasmic reticulum was the obvious compartment on which the gold particles were localized. Time course of MT immunoreactivity revealed that distribution of gold particles in hepatocytes increased gradually by 24 h, and decreased at 48 h after PH. Briefly, PH resulted in the sharpest increase in the expression of MT mRNA at 8 h and in the immunoreactivity of MT at 24 h, respectively. It is suggested that the increase of MT mRNA expression, the intensity of immunoreactivity and the specific localization of MT may be associated with the compensatory cell proliferation followed by PH.

• Fisheries and Aquatic Sciences
• /
• v.13 no.2
• /
• pp.112-117
• /
• 2010

Altered mRNA expression of two metallothionein isoforms (MT-IA and MT-IB) in response to acute heavy metal exposure was examined in mud loach, Misgurnus mizolepis, fry using a real-time RTPCR assay. Sublethal exposure (1 or 5 ${\mu}M$) to Cd, Cr, Fe, Mn, Ni, and Zn resulted in highly variable transcriptional responses of the two MT isoforms to the heavy metal ions, including upregulation, a steady state, and downregulation. Overall, the most potent inducer of both MT isoforms was Cd (up to 6-fold). Another exposure experiment using a series of doses of Cu revealed that the stimulation patterns of the two MT isoforms differed: MT-IA transcription was soon saturated at higher concentrations (about 2-fold at 1-4 ${\mu}M$ of Cu), whereas the activation of MT-IB was more dependent on the treatment dose (increased up to 5-fold at 3 ${\mu}M$). The isoform-specific allotment of constitutive and inducible functions was not as clear in fry as in adult tissues. Coordinated interaction between the MT-IA and MT-IB isoforms was hypothesized based on the finding that MT-IA represented a primary action under 'less stressful' or 'sublethal' conditions, whereas the activation of MT-IB became important under 'more stressful' or 'lethal' circumstances in this species.

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