Objective To study the gene expression of metallothionein 1 （MT-1） isoforms in human peripheral blood lymphocytes （HPBLs）. Methods The expression of mRNA representing the seven active MT-I genes was determined in ...Objective To study the gene expression of metallothionein 1 （MT-1） isoforms in human peripheral blood lymphocytes （HPBLs）. Methods The expression of mRNA representing the seven active MT-I genes was determined in HPBLs by quantitative RT-PCR before and after exposure to cadmium. Results Basal expressions of MT-IX, and MT-1A in HPBLs were similar to expression of housekeeping gene. In contrast, the basal gene expressions of MT- 1 H, IF, 1E, and 1G were a little transcripts in human HPBLs. No signal was detected for MT-1B. There was a sex difference （P〈0.05）. in basal gene expression of MT-1E. The levels of gene expression of MT-1A, 1E, IF, 1G, 1H, and 1X increased, but the level of MT-1B did not increase after exposure to cadmium. Conclusions Gene expressions of MT-1 G, MT-1 H, MT-1 F, and MT-1X in HPBLs can be used as a potential biomarker of cadmium exposure.展开更多
Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance li...Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance liquid chromatography (HPLC) was used to isolate and quantitate MT in livers of minks which were contaminated with heavy metals. MT isoforms (MT-I and MT-II) were eluted at approximately 11.3 and 14.3 min respectively from a DEAE-5 PW anion-exchange column with a Tris-HCl buffer (0.01 -0.25 mol/L, pH 8.6) and detected by UV absorbance at 254 nm. The cadmium concentrations in mink liver MT elutkms were determined by graphite furnace atomic absorption spectrometry (GFAAS) . Obvious increase in liver MT-I concentration rather than liver MT-II was found when the minks were contaminated by feeding contaminated fish captured from the heavy metal-polluted river. The cadmium concentration in mink liver MT-I also increased to some extent as the contaminated level increased.展开更多
Metallothioneins in Caenorhahditis elegans (CeMT-Ⅰ and Ⅱ) were punned by the combination of gel filtration ion-exchange chromatography.and high-performance liquid chromatography.Amino acid compositions and amino-ter...Metallothioneins in Caenorhahditis elegans (CeMT-Ⅰ and Ⅱ) were punned by the combination of gel filtration ion-exchange chromatography.and high-performance liquid chromatography.Amino acid compositions and amino-terminal sequences of CeMT-Ⅰ and Ⅱ were slightly different from those of vertebrate MTs previously reported, although cysteine residue contents were relatively high.Enzyme immunoassay using anti-CeMT-Ⅱ antibody showed the difference of antigenicity to rat MT-Ⅰ and Ⅱ and even to CeMT-Ⅰ. Immunohistochemical staining revealed the existence of CeMT-Ⅱ in the intestine and the eggs, suggesting the role of MT in detoxification and homeostasis of heavv metals. 1990 Academic Press.Inc.展开更多
Heavy metals, including cadmium (Cd), are widespread pollutants of great environmental concern because of their ac- cumulation and toxicity. Environmental conditions can affect the accumulation and elimination of Cd i...Heavy metals, including cadmium (Cd), are widespread pollutants of great environmental concern because of their ac- cumulation and toxicity. Environmental conditions can affect the accumulation and elimination of Cd in organisms. The aim of this study is to understand the respective responses of metallothioneins (MTs), P-glycoprotein (P-gp), and heat shock protein 70 (hsp70) genes in the mantle and digestive gland of the oyster Crassostrea gigas exposed to 10 g L 1 Cd for 28 days, followed by a depura- tion period of 35 days under different feeding strategies. The MT expression in the digestive gland was higher than in mantle, and was induced in a fluctuating pattern throughout the time of the whole experiment when the oyster was exposed to Cd. The results indicated an enhanced MT activity is required for Cd detoxification. Expression levels of P-gp in the mantle of Cd-exposed oysters fed with algae increased in the first two weeks of the accumulation phase. Then the induction weakened, but the expression still in- creased significantly compared with the control group fed without algae. The P-gp levels in the digestive gland were under-regulated during both the contamination and decontamination periods except in the group fed with Dicrateria inornata at day 0.083. The in- duction of P-gp is possibly related to the important role of pumping Cd out of the cell, while a major implication of P-gp expression inhibition would be a disruption of the protein synthesis. Hsp70 expression exhibited an overall decreasing trend. The highest relative hsp70 inhibition occurred during day 42 to day 63, with approximately 4-fold and 10-fold lower hsp70 levels as compared to the C.gigas feeding with no algae in the mantle and digestive gland, respectively. The induction of hsp70 may be explained by the re- folding of protein in presence of Cd, followed by the inhibition of hsp70 when the protein synthesis was disrupted.展开更多
To investigate the effects of cadmium exposure on insulin expression in rats. Methods Eighteen adult SD rats were administered cadmium subcutaneously （0.5, 1.0, and 2.0 mg/kg bw）. The effects on endocrine of pancrea...To investigate the effects of cadmium exposure on insulin expression in rats. Methods Eighteen adult SD rats were administered cadmium subcutaneously （0.5, 1.0, and 2.0 mg/kg bw）. The effects on endocrine of pancreas were assessed. The levels of cadmium and zinc in pancreas, blood and urine glucose, serum insulin and urine NAG （N-acyetyl-β-glucosaminidase） were determined. The gene expressions of metallothionein （MT） and insulin were also measured, and the oral glucose tolerance tests （OGTT） were carried out. Results The contents of cadmium in pancreas in cadmium-treated rats were higher than that in the control group, which was associated with slight increase of zinc in pancreas. Cadmium-exposed rats （1.0 and 2.0 mg/kg bw） demonstrated a marked glucose intolerance. But the levels of serum insulin did not change significantly after cadmium administration, and the UNAG had no change in Cd-treated group. The gene expression of insulin decreased in 1.0 and 2.0 mg/kg bw cadmium-exposed groups, compared with the control group. The expression of MT-I was higher in the groups exposed to 1.0 and 2.0 mg/kg bw cadmium while the expression of MT-II was higher in the group exposed to 2.0 mg/kg bw cadmium. Conclusions Cadmium may be accumulated in the pancreas, resulting in the change of the expression of insulin, MT-I and MT-Ⅱ genes. Cadmium can influence the biosynthesis of insulin, but does not induce the release of insulin. The dysfunction of pancreas occurs earlier than that of kidney after administration of cadmium.展开更多
Objective To study the possible intervention of isoflavones in cytotoxicity induced by cadmium in vascular endothelial cells. Methods An ECV 304 cell line derived from human umbilical vein endothelial cells was adopte...Objective To study the possible intervention of isoflavones in cytotoxicity induced by cadmium in vascular endothelial cells. Methods An ECV 304 cell line derived from human umbilical vein endothelial cells was adopted. Genistein / daidzein was added prior to or simultaneously with CdCl2, cell viability was determined by MTT assay, and metallothionein mRNA expression was monitored by RT-PCR method. Results Cell viability was higher in isoflavone and CdCl2 co-treated groups than that in CdCl2 treated group, with CdCl2 concentration at 10, 20, 40, and 80 μmol/L, respectively. However this increase was not observed in the group treated with CdCl2 at a concentration of 60 μmol/L. Isoflavones (10-10 mol/L to 10-5 mol/L) were added 24 h before cells were challenged with 80 μmol/L CdCl2 for 24 h or simultaneously with 80 μmol/L CdCl2. Genistein increased cell viability only at 10-5 mol/L, while daidzein caused a dose-dependent increase from 10-10 mol/L to 10-5 mol/L in co-treatment with CdCl2. In pre-treatment, genistein (10-7 to 10-5 mol/L) increased cell viability whereas only 10-5 mol/L of daidzein exerted protection. Apparent protection could be found when the cells were pre-treated with 10-5 mol/L isoflavones for over 12 h, whereas 24 h incubation was required in such a co-treatment, with the exception of daidzein that had a significant protection in only 3 h. Isoflavones (10-6 mol/L) incubated for 3 h to 24 h, increased MT IIA and MT IF mRNA expression, but the induction could not last for more than 24 h. Co-treatment with isoflavones could induce an additional induction of MT IIA mRNA expression in cells exposed to cadmium. However, the additional induction of MT IIA and MT IF mRNA was not seen when pre-treatment was carried out with isoflavones, with the exception of an increase in MT IIA mRNA expression in the daidzein pre-treated group. Conclusion Genistein/daidzein could reverse the cytotoxicity of cadmium either in pre-treatment or in co-treatment. The protection is the strongest in 10-5 mol/L of isoflavones with a dose-dependent pattern. There are differences between genistein and daidzein in their protective effects. Whether the protection of isoflavones is related to their capacity of inducing MT mRNA expression remains to be elucidated.展开更多
Common silver barb, Puntius gonionotus, exposed to the nominal concentration of 0.06 mg/L Cd for 60 d, were assessed for histopathological alterations （gills, liver and kidney）, metal accumulation, and metallothione...Common silver barb, Puntius gonionotus, exposed to the nominal concentration of 0.06 mg/L Cd for 60 d, were assessed for histopathological alterations （gills, liver and kidney）, metal accumulation, and metallothionein （MT） mRNA expression. Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae, vacuolization in hepatocytes, and prominent tubular and glomerular damage in the kidney. In addition, kidney accumulated the highest content of cadmium, more than gills and liver. Expression of MT mRNA was increased in both liver and kidney of treated fish. Hepatic MT levels remained high after fish were removed to Cd-free water. In contrast, MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water. The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.展开更多
A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 ...A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 dalton.a UV absorption peak at 260 instead of 280 nm like most proteins;andhas high affinity towards binding with radioactive labeled <sup>109</sup>Cd.These characteristics are similarto that of metallothioneins reported for many vertebrate and invertebrate,marine and terrestrialanimals.After the brine shrimp is exposed to a small amount of Cd<sup>2+</sup>for 24 h,a large amount ofmetallothionein can be isolated,showing the inducibility of this detoxifying protein in the adult Artemiain a short period of time.展开更多
基金This work was supported by the National 973 Program of China 2002 CB 512905
文摘Objective To study the gene expression of metallothionein 1 （MT-1） isoforms in human peripheral blood lymphocytes （HPBLs）. Methods The expression of mRNA representing the seven active MT-I genes was determined in HPBLs by quantitative RT-PCR before and after exposure to cadmium. Results Basal expressions of MT-IX, and MT-1A in HPBLs were similar to expression of housekeeping gene. In contrast, the basal gene expressions of MT- 1 H, IF, 1E, and 1G were a little transcripts in human HPBLs. No signal was detected for MT-1B. There was a sex difference （P〈0.05）. in basal gene expression of MT-1E. The levels of gene expression of MT-1A, 1E, IF, 1G, 1H, and 1X increased, but the level of MT-1B did not increase after exposure to cadmium. Conclusions Gene expressions of MT-1 G, MT-1 H, MT-1 F, and MT-1X in HPBLs can be used as a potential biomarker of cadmium exposure.
文摘Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance liquid chromatography (HPLC) was used to isolate and quantitate MT in livers of minks which were contaminated with heavy metals. MT isoforms (MT-I and MT-II) were eluted at approximately 11.3 and 14.3 min respectively from a DEAE-5 PW anion-exchange column with a Tris-HCl buffer (0.01 -0.25 mol/L, pH 8.6) and detected by UV absorbance at 254 nm. The cadmium concentrations in mink liver MT elutkms were determined by graphite furnace atomic absorption spectrometry (GFAAS) . Obvious increase in liver MT-I concentration rather than liver MT-II was found when the minks were contaminated by feeding contaminated fish captured from the heavy metal-polluted river. The cadmium concentration in mink liver MT-I also increased to some extent as the contaminated level increased.
文摘Metallothioneins in Caenorhahditis elegans (CeMT-Ⅰ and Ⅱ) were punned by the combination of gel filtration ion-exchange chromatography.and high-performance liquid chromatography.Amino acid compositions and amino-terminal sequences of CeMT-Ⅰ and Ⅱ were slightly different from those of vertebrate MTs previously reported, although cysteine residue contents were relatively high.Enzyme immunoassay using anti-CeMT-Ⅱ antibody showed the difference of antigenicity to rat MT-Ⅰ and Ⅱ and even to CeMT-Ⅰ. Immunohistochemical staining revealed the existence of CeMT-Ⅱ in the intestine and the eggs, suggesting the role of MT in detoxification and homeostasis of heavv metals. 1990 Academic Press.Inc.
基金supported by the Earmarked Fund for Modern Agro-industry Technology Research System in Shandong Province (No. SDAIT-14)the major Agricultural Applied Technological Innovation Program in Shandong Province: Construction and Demonstration of Ecological Farming Model of Monomeric Triploid Oyster
文摘Heavy metals, including cadmium (Cd), are widespread pollutants of great environmental concern because of their ac- cumulation and toxicity. Environmental conditions can affect the accumulation and elimination of Cd in organisms. The aim of this study is to understand the respective responses of metallothioneins (MTs), P-glycoprotein (P-gp), and heat shock protein 70 (hsp70) genes in the mantle and digestive gland of the oyster Crassostrea gigas exposed to 10 g L 1 Cd for 28 days, followed by a depura- tion period of 35 days under different feeding strategies. The MT expression in the digestive gland was higher than in mantle, and was induced in a fluctuating pattern throughout the time of the whole experiment when the oyster was exposed to Cd. The results indicated an enhanced MT activity is required for Cd detoxification. Expression levels of P-gp in the mantle of Cd-exposed oysters fed with algae increased in the first two weeks of the accumulation phase. Then the induction weakened, but the expression still in- creased significantly compared with the control group fed without algae. The P-gp levels in the digestive gland were under-regulated during both the contamination and decontamination periods except in the group fed with Dicrateria inornata at day 0.083. The in- duction of P-gp is possibly related to the important role of pumping Cd out of the cell, while a major implication of P-gp expression inhibition would be a disruption of the protein synthesis. Hsp70 expression exhibited an overall decreasing trend. The highest relative hsp70 inhibition occurred during day 42 to day 63, with approximately 4-fold and 10-fold lower hsp70 levels as compared to the C.gigas feeding with no algae in the mantle and digestive gland, respectively. The induction of hsp70 may be explained by the re- folding of protein in presence of Cd, followed by the inhibition of hsp70 when the protein synthesis was disrupted.
基金This study was supported by 973 Program of China (2002 CB 512905).
文摘To investigate the effects of cadmium exposure on insulin expression in rats. Methods Eighteen adult SD rats were administered cadmium subcutaneously （0.5, 1.0, and 2.0 mg/kg bw）. The effects on endocrine of pancreas were assessed. The levels of cadmium and zinc in pancreas, blood and urine glucose, serum insulin and urine NAG （N-acyetyl-β-glucosaminidase） were determined. The gene expressions of metallothionein （MT） and insulin were also measured, and the oral glucose tolerance tests （OGTT） were carried out. Results The contents of cadmium in pancreas in cadmium-treated rats were higher than that in the control group, which was associated with slight increase of zinc in pancreas. Cadmium-exposed rats （1.0 and 2.0 mg/kg bw） demonstrated a marked glucose intolerance. But the levels of serum insulin did not change significantly after cadmium administration, and the UNAG had no change in Cd-treated group. The gene expression of insulin decreased in 1.0 and 2.0 mg/kg bw cadmium-exposed groups, compared with the control group. The expression of MT-I was higher in the groups exposed to 1.0 and 2.0 mg/kg bw cadmium while the expression of MT-II was higher in the group exposed to 2.0 mg/kg bw cadmium. Conclusions Cadmium may be accumulated in the pancreas, resulting in the change of the expression of insulin, MT-I and MT-Ⅱ genes. Cadmium can influence the biosynthesis of insulin, but does not induce the release of insulin. The dysfunction of pancreas occurs earlier than that of kidney after administration of cadmium.
基金This study was supported by 973 Program of China (2002 CB 512905).
文摘Objective To study the possible intervention of isoflavones in cytotoxicity induced by cadmium in vascular endothelial cells. Methods An ECV 304 cell line derived from human umbilical vein endothelial cells was adopted. Genistein / daidzein was added prior to or simultaneously with CdCl2, cell viability was determined by MTT assay, and metallothionein mRNA expression was monitored by RT-PCR method. Results Cell viability was higher in isoflavone and CdCl2 co-treated groups than that in CdCl2 treated group, with CdCl2 concentration at 10, 20, 40, and 80 μmol/L, respectively. However this increase was not observed in the group treated with CdCl2 at a concentration of 60 μmol/L. Isoflavones (10-10 mol/L to 10-5 mol/L) were added 24 h before cells were challenged with 80 μmol/L CdCl2 for 24 h or simultaneously with 80 μmol/L CdCl2. Genistein increased cell viability only at 10-5 mol/L, while daidzein caused a dose-dependent increase from 10-10 mol/L to 10-5 mol/L in co-treatment with CdCl2. In pre-treatment, genistein (10-7 to 10-5 mol/L) increased cell viability whereas only 10-5 mol/L of daidzein exerted protection. Apparent protection could be found when the cells were pre-treated with 10-5 mol/L isoflavones for over 12 h, whereas 24 h incubation was required in such a co-treatment, with the exception of daidzein that had a significant protection in only 3 h. Isoflavones (10-6 mol/L) incubated for 3 h to 24 h, increased MT IIA and MT IF mRNA expression, but the induction could not last for more than 24 h. Co-treatment with isoflavones could induce an additional induction of MT IIA mRNA expression in cells exposed to cadmium. However, the additional induction of MT IIA and MT IF mRNA was not seen when pre-treatment was carried out with isoflavones, with the exception of an increase in MT IIA mRNA expression in the daidzein pre-treated group. Conclusion Genistein/daidzein could reverse the cytotoxicity of cadmium either in pre-treatment or in co-treatment. The protection is the strongest in 10-5 mol/L of isoflavones with a dose-dependent pattern. There are differences between genistein and daidzein in their protective effects. Whether the protection of isoflavones is related to their capacity of inducing MT mRNA expression remains to be elucidated.
文摘Common silver barb, Puntius gonionotus, exposed to the nominal concentration of 0.06 mg/L Cd for 60 d, were assessed for histopathological alterations （gills, liver and kidney）, metal accumulation, and metallothionein （MT） mRNA expression. Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae, vacuolization in hepatocytes, and prominent tubular and glomerular damage in the kidney. In addition, kidney accumulated the highest content of cadmium, more than gills and liver. Expression of MT mRNA was increased in both liver and kidney of treated fish. Hepatic MT levels remained high after fish were removed to Cd-free water. In contrast, MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water. The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.
文摘A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 dalton.a UV absorption peak at 260 instead of 280 nm like most proteins;andhas high affinity towards binding with radioactive labeled <sup>109</sup>Cd.These characteristics are similarto that of metallothioneins reported for many vertebrate and invertebrate,marine and terrestrialanimals.After the brine shrimp is exposed to a small amount of Cd<sup>2+</sup>for 24 h,a large amount ofmetallothionein can be isolated,showing the inducibility of this detoxifying protein in the adult Artemiain a short period of time.
