Metallothioneins （MTs） are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions. A cadmium metallothionein （EcMT-Cd） cDNA with a 189 bp open reading frame （ORF） that encoded...Metallothioneins （MTs） are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions. A cadmium metallothionein （EcMT-Cd） cDNA with a 189 bp open reading frame （ORF） that encoded a 62 amino acid protein was obtained from Exopalaemon carinicauda. Seventeen cysteines were in the deduced amino acid sequence, and the cysteine （Cys）-rich characteristic was revealed in different metallothioneins in other species. In addition, the deduced amino acid sequence did not contain any aromatic amino acid residues, such as tyrosine （Tyr）, tryptophan （Trp）, and phenylalanine （Phe）. EcMT- Cd mRNA was expressed in all tested tissues （the ovary, muscle, stomach, and hepatopancreas）, and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50 pmol/L CuSO4 or 2.5 gmol/L CdC12. The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4 for 12 h and down-regulated in shrimps exposed to CdC12 for 12 h. After 24 h exposure to both metals, its expression was down-regulated. By contrast, at 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdC12. The transcript of EcMT-Cd was very low or even absent before the zoea stage, and the expression of EcMT-Cd was detected from mysis larvae-I, then its expression began to rise. In conclusion, a cadmium MT exists in E. carinicauda that is expressed in different tissues and during different developmental stages, and responds to the challenge with heavy metal ions, which provides a clue to understanding the function of cadmium MT展开更多
Heavy metals currently pose one of the most serious problems in terms of environmental protection. We analysed the effect of cadmium and mercury salts upon chlorophyll fluorescence emision of Microcystis aeruginosa, C...Heavy metals currently pose one of the most serious problems in terms of environmental protection. We analysed the effect of cadmium and mercury salts upon chlorophyll fluorescence emision of Microcystis aeruginosa, Cylindrospermopsis raciborskii and Aphanizomenon gracile. Time of incubation （3, 12 and 24 h） and salts concentration（1 μM, 10 μM, 100μM） influenced the emision. The higher the salt concentration and the longer the time of incubation, the greater the influence on inhibition of chlorophyll fluorescence was observed. Our results might indicate that nontoxic strains of M. aeruginosa MAKR0205 can have a high tolerance to heavy metal ions and ability of their detoxication. Further studies are necessary to confirm their potential ability in the water purification.展开更多
基金Supported by the National Natural Science Foundation of China(No.311720449)the National High Technology Research and Development Program of China(No.2012AA10A401)the Scientific Research Foundation for the Excellent Middle-Aged and Youth Scientists of Shandong Province of China(No.BS2010SW039)
文摘Metallothioneins （MTs） are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions. A cadmium metallothionein （EcMT-Cd） cDNA with a 189 bp open reading frame （ORF） that encoded a 62 amino acid protein was obtained from Exopalaemon carinicauda. Seventeen cysteines were in the deduced amino acid sequence, and the cysteine （Cys）-rich characteristic was revealed in different metallothioneins in other species. In addition, the deduced amino acid sequence did not contain any aromatic amino acid residues, such as tyrosine （Tyr）, tryptophan （Trp）, and phenylalanine （Phe）. EcMT- Cd mRNA was expressed in all tested tissues （the ovary, muscle, stomach, and hepatopancreas）, and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50 pmol/L CuSO4 or 2.5 gmol/L CdC12. The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4 for 12 h and down-regulated in shrimps exposed to CdC12 for 12 h. After 24 h exposure to both metals, its expression was down-regulated. By contrast, at 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdC12. The transcript of EcMT-Cd was very low or even absent before the zoea stage, and the expression of EcMT-Cd was detected from mysis larvae-I, then its expression began to rise. In conclusion, a cadmium MT exists in E. carinicauda that is expressed in different tissues and during different developmental stages, and responds to the challenge with heavy metal ions, which provides a clue to understanding the function of cadmium MT
文摘Heavy metals currently pose one of the most serious problems in terms of environmental protection. We analysed the effect of cadmium and mercury salts upon chlorophyll fluorescence emision of Microcystis aeruginosa, Cylindrospermopsis raciborskii and Aphanizomenon gracile. Time of incubation （3, 12 and 24 h） and salts concentration（1 μM, 10 μM, 100μM） influenced the emision. The higher the salt concentration and the longer the time of incubation, the greater the influence on inhibition of chlorophyll fluorescence was observed. Our results might indicate that nontoxic strains of M. aeruginosa MAKR0205 can have a high tolerance to heavy metal ions and ability of their detoxication. Further studies are necessary to confirm their potential ability in the water purification.
