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Zhou L, Cao L, Wang X, Wang M, Wang H, Zhong Z, Xu Z, Chen H, Li L, Li M, Wang H, Zhang H, Lian C, Sun Y, Li C. Metal adaptation strategies of deep-sea Bathymodiolus mussels from a cold seep and three hydrothermal vents in the West Pacific. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136046. [PMID: 31863974 DOI: 10.1016/j.scitotenv.2019.136046] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/30/2019] [Accepted: 12/08/2019] [Indexed: 06/10/2023]
Abstract
Deep-sea Bathymodiolus mussels are ubiquitous in most cold seeps and hydrothermal fields, where they have adapted to various toxic environments including high metal exposure. However, there is scarce knowledge of metal accumulation and metal-related biomarkers in B. mussels. Here, we present data for metal concentrations (Ag, Cd, Cr, Cu, Fe, Mn, Pb, and Zn) and metal related biomarkers (superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase-GPX, glutathione-GSH, metallothioneins-MTs, and lipid peroxidation-LPO) in different tissues of B. mussels from four different deep-sea geochemical settings: one cold seep and three vent fields in the West Pacific Ocean. Results showed that mussel gills generally exhibited higher metal enrichment than the mantle. Mussels from hydrothermal vents usually had higher metal concentrations (Fe, Cr, Cd, and Pb) than those from cold seep, which could be related to their higher contents in fluids or sediments. However, despite quite different metals loads among the geochemical environment settings, Mn, Zn, and Cu concentrations varied over a smaller range across the sampling sites, implying biological regulation by deep-sea mussels for these elements. Several statistically significant correlations were observed between SOD, CAT, GSH, MTs, and metal levels in analyzed tissues. Although the vent ecosystem is harsher than the cold seep ecosystem, according to our results their mussels' biomarker levels were not so different. This finding suggests that some adaptive or compensatory mechanisms may occur in chronically polluted deep-sea mussels. Principal component analysis allowed for distinguishing different deep-sea settings, indicating that B. mussels are robust indicators of their living environments. We also compared our results with those reported for coastal mussels. To our best knowledge, this is the first integrated study to report metal accumulation and metal-related biomarkers in the deep-sea B. mussels from the West Pacific.
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Affiliation(s)
- Li Zhou
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lei Cao
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xiaocheng Wang
- National Marine Environmental Monitoring Center, Dalian 116023, China
| | - Minxiao Wang
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Haining Wang
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 10049, China
| | - Zhaoshan Zhong
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 10049, China
| | - Zheng Xu
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 10049, China
| | - Hao Chen
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Leilei Li
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Mengna Li
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 10049, China
| | - Hao Wang
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Huan Zhang
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Chao Lian
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yan Sun
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Chaolun Li
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 10049, China.
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Zhang B, Fang CD, Xu JH, Cao HJ. Depuration of Cadmium from Blue Mussel (Mytilus edulis) by Protein Hydrolysate-Fe 2+ Complex: The Role of Metallothionein. J Food Sci 2017; 82:2767-2773. [PMID: 29030874 DOI: 10.1111/1750-3841.13939] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/30/2017] [Accepted: 09/06/2017] [Indexed: 11/29/2022]
Abstract
Metallothionein (MT) plays a major role in the detoxification of toxic metal ions in mussel. This study served to investigate the effects of prepared protein hydrolysate-Fe2+ (PH-Fe2+ ) on depuration of cadmium salt (Cd2+ ) from blue mussel (Mytilus edulis). The results indicated that Cd2+ concentrations in control ranged from 46.1 to 47.1 μg/g during 15 d of depuration. While, 40 mg/L PH-Fe2+ feed mussels exhibited obvious changes in Cd2+ concentration variables, which decreased by 22.8 μg/g after 15 d of depuration, making them significantly lower than the values of the control. Our assumption was that Cd2+ could be dissociated effectively from the complex of MT-Cd2+ in mussels affected by the incorporation of PH-Fe2+ during the feeding period. Further results of homology modeling and molecular dynamics (MD) confirmed that the combined power between MT and Cd2+ weakened significantly by PH-Fe2+ . This condition affected the charge density and/or the loop flexibility of MT and decreased the interaction energy within MT-Cd2+ complex and resulted in the release of Cd2+ from the complex, thereby exhibiting excretion detoxification. Finally, by comparing the experimental results to MD results, significant positive correlations were observed between PH-Fe2+ and the depuration of Cd2+ from MT-Cd2+ complex. Overall, the findings of this study may help better understand the depuration mechanisms of Cd2+ combined with MT, and the PH-Fe2+ can be recommended as a depuration agent to decrease Cd2+ concentrations in mussels. PRACTICAL APPLICATION Metallothionein (MT) is a low-molecular-weight protein with high metal-ion affinity. If the intracellular concentrations of metals are too high or if toxic metals are present within the cell, then the synthesis of MTs is induced and generated. In our previous work, it was found that the prepared hydrolysate-metal element complex showed obvious depuration activity of heavy metals (Cd2+ ) from blue mussel (Mytilus edulis). This study provided further the depuration mechanisms of Cd2+ from mussel (M. edulis), in particular to the role of MT and its chelate during the depuration process.
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Affiliation(s)
- Bin Zhang
- Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, Zhejiang Ocean Univ., Zhoushan, Zhejiang, China.,School of Medicine, Ocean Univ. of China, No.1 Searoad, Marine building 214-1, Changzhi Island, Lincheng, Zhoushan, Zhejiang, China
| | - Chuan-Dong Fang
- Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, Zhejiang Ocean Univ., Zhoushan, Zhejiang, China
| | - Jun-Hui Xu
- Zhoushan Entry-Exit Inspection and Quarantine Bureau, Zhoushan, China
| | - Hui-Juan Cao
- Zhoushan Entry-Exit Inspection and Quarantine Bureau, Zhoushan, China
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Zheng P, Wang M, Li C, Sun X, Wang X, Sun Y, Sun S. Insights into deep-sea adaptations and host-symbiont interactions: A comparative transcriptome study on Bathymodiolus
mussels and their coastal relatives. Mol Ecol 2017; 26:5133-5148. [DOI: 10.1111/mec.14160] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/09/2023]
Affiliation(s)
- Ping Zheng
- Key Laboratory of Marine Ecology and Environmental Sciences; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
- University of Chinese Academy of Sciences; Beijing China
| | - Minxiao Wang
- Key Laboratory of Marine Ecology and Environmental Sciences; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
- Deep Sea Research Center; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
| | - Chaolun Li
- Key Laboratory of Marine Ecology and Environmental Sciences; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
- University of Chinese Academy of Sciences; Beijing China
- Deep Sea Research Center; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
- Laboratory for Marine Ecology and Environmental Science; Qingdao National Laboratory for Marine Science and Technology; Qingdao China
| | | | - Xiaocheng Wang
- Key Laboratory of Marine Ecology and Environmental Sciences; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
- University of Chinese Academy of Sciences; Beijing China
| | - Yan Sun
- Key Laboratory of Marine Ecology and Environmental Sciences; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
| | - Song Sun
- Key Laboratory of Marine Ecology and Environmental Sciences; Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
- University of Chinese Academy of Sciences; Beijing China
- Laboratory for Marine Ecology and Environmental Science; Qingdao National Laboratory for Marine Science and Technology; Qingdao China
- Jiaozhou Bay Marine Ecosystem Research Station; Chinese Academy of Sciences; Qingdao China
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Le TTY, Zimmermann S, Sures B. How does the metallothionein induction in bivalves meet the criteria for biomarkers of metal exposure? ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 212:257-268. [PMID: 26854695 DOI: 10.1016/j.envpol.2016.01.070] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/21/2016] [Accepted: 01/24/2016] [Indexed: 06/05/2023]
Abstract
Metallothionein (MT) concentrations in the whole soft tissue or in a particular tissue of bivalves have widely been used in ecotoxicological studies and biomonitoring programmes. This approach is based on the reported results on the enhancement of MT induction in bivalves in response to metal exposure. The validity of using MT induction as a biomarker is briefly assessed in the present study. The sensitivity of MT induction in these organisms is questionable due to the high basal MT level as well as the high natural variability related to the effects of a number of biotic and abiotic factors, which are not well described yet. Moreover, the relationship between exposure to metals, the toxic effects of that exposure, and the appearance of MT in soft tissue, is not well characterized. A variety of factors may influence the appearance and distribution of MT: 1) the uneven distribution of metals in particular portions of the soft tissue and in particular subcellular compartments; 2) pre-exposure to metals, perhaps at non-toxic levels; 3) metal-metal competition and metal-protein interactions; and 4) tissue-specific induction, functions, and isoforms of MT. Therefore, attention is required when using MT induction in bivalves for assessment of metal exposure or consequent toxic effects. The MT concentration can be a reliable indicator only when it is considered in relation with metal uptake kinetics and subcellular partitioning while specifying the isoform of MT synthesised and considering various confounding factors. The kinetic turnover of MT may provide useful information on metal exposure and biological effects since it covers both the synthesis and breakdown of MT as well as the chemical species of metals accumulated and MT.
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Affiliation(s)
- T T Yen Le
- Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Germany.
| | - Sonja Zimmermann
- Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Germany
| | - Bernd Sures
- Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Germany; Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
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5
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Zahid MT, Shakoori FR, Zulifqar S, Ahmed I, Al-Ghanim K, Mehboob S, Shakoori AR. Molecular Characterization of a Copper Metallothionein Gene From a Ciliate Tetrahymena farahensis. J Cell Biochem 2016; 117:1843-54. [PMID: 26754785 DOI: 10.1002/jcb.25484] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 01/06/2016] [Indexed: 11/06/2022]
Abstract
A new copper metallothionein (TfCuMT) gene has been identified from a locally isolated ciliate Tetrahymena farahensis. It contains 327 nucleotides encoding a peptide chain of 108 amino acids and belongs to class MTT2 and subfamily 7b. Amplification from both gDNA and mRNA confirmed the intronless nature of this gene. Like most of the metallohtioneins, cysteine residues contribute nearly 30% content with the specific CKC motifs. Structural repeats present in peptide sequence of TfCuMT indicate internal duplication of gene at some stage of gene evolution. The predicted model of copper metallothionein protein showed that copper ions are mainly chelated by thiol sulfur of cysteine residues and are embedded in the folds of polypeptide chain. For in vivo expression of TfCuMT in Escherichia coli host cells the classical stop codons, which coded for glutamine in the ciliate were mutated to CAA and CAG through site directed mutagenesis. The mutated gene showed higher expression in pET28a expression vector compared with pET21a. Optimum expression was obtained after 6-8 h of 0.1 mM IPTG induction. Stability of His tagged TfCuMT in 5% SDS was low, with half-life of about 104 min. Presence of 1.0 μM copper increased the expression level by 1.65-fold. Presence of 100 μM Cysteine in culture medium caused 2.4-fold increase in expression level. His tagged TfCuMT was purified through affinity chromatography using NTN-His binding resin in the presence of 0.1 M imidazole and NaCl. The modeled structure of the TfCuMT showed a cleft for Cu binding with correct orientation of Cys residues in the motif CKC. J. Cell. Biochem. 117: 1843-1854, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Muhammad Tariq Zahid
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan.,Departmenmt of Zoology, GC University, Katchery Road, Lahore, Pakistan
| | - Farah Rauf Shakoori
- Departmenmt of Zoology, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan
| | - Soumble Zulifqar
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan
| | - Ishtiaq Ahmed
- Institute of Industrial Biotechnology, GC University, Katchery Road, Lahore, Pakistan
| | - Khalid Al-Ghanim
- Department of Zoology, College of Science, King Saud University, PO Box 24555, Riyadh 11451, Kingdom of Saudi Arabia
| | - Shahid Mehboob
- Department of Zoology, College of Science, King Saud University, PO Box 24555, Riyadh 11451, Kingdom of Saudi Arabia
| | - Abdul Rauf Shakoori
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan.,Department of Zoology, College of Science, King Saud University, PO Box 24555, Riyadh 11451, Kingdom of Saudi Arabia
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6
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Isani G, Carpenè E. Metallothioneins, unconventional proteins from unconventional animals: a long journey from nematodes to mammals. Biomolecules 2014; 4:435-57. [PMID: 24970224 PMCID: PMC4101491 DOI: 10.3390/biom4020435] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/19/2014] [Accepted: 03/21/2014] [Indexed: 12/19/2022] Open
Abstract
Metallothioneins (MTs) are ubiquitous low molecular weight cysteine-rich proteins characterized by high affinity for d10 electron configuration metals, including essential (Zn and Cu) and non-essential (Cd and Hg) trace elements. The biological role of these ancient and well-conserved multifunctional proteins has been debated since MTs were first discovered in 1957. Their main hypothesized functions are: (1) homeostasis of Zn and Cu; (2) detoxification of Cd, and Hg; and (3) free radical scavenging. This review will focus on MTs in unconventional animals, those not traditionally studied in veterinary medicine but of increasing interest in this field of research. Living in different environments, these animals represent an incredible source of physiological and biochemical adaptations still partly unexplored. The study of metal-MT interactions is of great interest for clinicians and researchers working in veterinary medicine, food quality and endangered species conservation.
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Affiliation(s)
- Gloria Isani
- Department of Veterinary Medical Sciences, Alma Mater Studiorum-University of Bologna, via Tolara di sopra, 50, Ozzano Emilia, Bologna 40064, Italy.
| | - Emilio Carpenè
- Department of Veterinary Medical Sciences, Alma Mater Studiorum-University of Bologna, via Tolara di sopra, 50, Ozzano Emilia, Bologna 40064, Italy.
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Whaley-Martin KJ, Koch I, Moriarty M, Reimer KJ. Arsenic speciation in blue mussels (Mytilus edulis) along a highly contaminated arsenic gradient. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3110-8. [PMID: 22329691 DOI: 10.1021/es203812u] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Arsenic is naturally present in marine ecosystems, and these can become contaminated from mining activities, which may be of toxicological concern to organisms that bioaccumulate the metalloid into their tissues. The toxic properties of arsenic are dependent on the chemical form in which it is found (e.g., toxic inorganic arsenicals vs nontoxic arsenobetaine), and two analytical techniques, high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and X-ray absorption spectroscopy (XAS), were used in the present study to examine the arsenic species distribution in blue mussels (Mytilus edulis) obtained from an area where there is a strong arsenic concentration gradient as a consequence of mining impacted sediments. A strong positive correlation was observed between the concentration of inorganic arsenic species (arsenic compounds with no As-C bonds) and total arsenic concentrations present in M. edulis tissues (R(2) = 0.983), which could result in significant toxicological consequences to the mussels and higher trophic consumers. However, concentrations of organoarsenicals, dominated by arsenobetaine, remained relatively constant regardless of the increasing As concentration in M. edulis tissue (R(2) = 0.307). XANES bulk analysis and XAS two-dimensional mapping of wet M. edulis tissue revealed the presence of predominantly arsenic-sulfur compounds. The XAS mapping revealed that the As(III)-S and/or As(III) compounds were concentrated in the digestive gland. However, arsenobetaine was found in small and similar concentrations in the digestive gland as well as the surrounding tissue suggesting arsenobetaine may being used in all of the mussel's cells in a physiological function such as an intracellular osmolyte.
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Affiliation(s)
- K J Whaley-Martin
- Environmental Sciences Group, Royal Military College of Canada, PO Box 17000 Station Forces, Kingston, Ontario K7K 7B4, Canada
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Aceto S, Formisano G, Carella F, De Vico G, Gaudio L. The metallothionein genes of Mytilus galloprovincialis: genomic organization, tissue expression and evolution. Mar Genomics 2011; 4:61-8. [PMID: 21429466 DOI: 10.1016/j.margen.2011.01.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/03/2011] [Accepted: 01/03/2011] [Indexed: 11/29/2022]
Abstract
Recently, increasing interest has been directed to the study of metallothioneins (MTs), which are small proteins that are able to bind metal ions. The induction of MT synthesis after exposure to metal or other environmental contaminants in a large number of aquatic invertebrates makes these proteins good biomarkers in water monitoring programs. Within bivalves, the species Mytilus galloprovincialis and Mytilus edulis represent model organisms for these types of studies, as well as for molecular studies regarding the expression and characterization of MT encoding genes. In the present paper, we focused on the genomic characterization, evolutionary, and tissue-expression analyses of the MT-10, MT-10 Intronless, and MT-20 genes in M. galloprovincialis. The comparison of the genomic sequences showed the presence of long nucleotide stretches within the introns of the MT genes that are conserved between M. galloprovincialis and M. edulis. These non-coding conserved sequences may contain regulatory motifs. Real-Time RT-PCR experiments revealed that, at the basal conditions, the MT-10 and MT-10 Intronless genes are expressed at levels considerably higher than the MT-20 gene, mainly in the digestive gland and gill tissue. The strong induction of the MT-20 gene expression detected in a field-collected sample is associated with the up-regulation of both the MT-10 and MT-10 Intronless genes. Evolutionary analysis revealed signals of localized positive selection that, together with the tissue-expression data, support a possible functional diversification between the MTs encoded by the MT-10 and MT-10 Intronless genes.
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Affiliation(s)
- Serena Aceto
- Department of Biological Sciences, University of Naples Federico II, 80134 Napoli, Italy.
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9
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Lilja K, Prevodnik A, Gardeström J, Elfwing T, Tedengren M, Bollner T. Regional differences in mRNA responses in blue mussels within the Baltic proper. Comp Biochem Physiol C Toxicol Pharmacol 2008; 148:101-6. [PMID: 18502694 DOI: 10.1016/j.cbpc.2008.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 04/02/2008] [Accepted: 04/03/2008] [Indexed: 11/26/2022]
Abstract
Mussels (Mytilus sp.) from two regions along the permanent salinity gradient within the Baltic proper were exposed to copper (35 ppb) or petrol (0.3 mL/L) for 10 days and analyzed for mRNA expressions in gill tissue. Expression of mRNAs for the heat shock proteins HSP70 and HSP90 was significantly induced by copper, but not by petrol. For the metallothioneins MT10 and MT20, regional differences in mRNA expressions could be seen. In mussels from the northern Baltic proper, MT20 expression increased 2.8 and 3.4 times, after exposure to copper and petrol, respectively. In contrast, no change could be seen in MT20 expression for mussels from the southern Baltic proper. MT10 showed a peculiar expression not previously described. For some mussels, no expression at all was detected, some showed a weak expression and for some individuals a strong expression could be seen. For the mussels from the southern Baltic proper, the number of individuals with a strong expression of MT10 increased from 1 out of 18 (control), to 7 and 8, after exposure to copper and petrol, respectively. The results clearly show that responses vary between different regions within the Baltic proper, which emphasises the importance to study interactions between contaminants, populations and regions.
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Affiliation(s)
- Karl Lilja
- School of Life Sciences, Södertörn University College SE-141 89 Huddinge, Sweden.
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10
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Cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in Tetrahymena pigmentosa. Gene 2008; 423:29-35. [PMID: 18675523 DOI: 10.1016/j.gene.2008.04.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 04/25/2008] [Accepted: 04/25/2008] [Indexed: 11/20/2022]
Abstract
A novel cadmium-inducible metallothionein (MT) gene (Tpig-MT1) was cloned and sequenced from the ciliate Tetrahymena pigmentosa. The number of deduced amino acids is 118. The polypeptide possesses CCC and CC clusters characteristic of typical Tetrahymena Cd-inducible MTs. The structure of Tpig-MT1 is different from the reported Cd-MT in T. pyriformis, T. thermophila and T. pigmentosa. Tpig-MT1 contains two intragenic tandem repeats with 72.9% identity described as Tpig-MT1 (repeat A1) and Tpig-MT1 (repeat A2). The transcriptional response of Tpig-MT1 gene to different heavy metals (Cd, Cu, Zn, Hg, Pb) and oxidative stress (H(2)O(2)) was measured using real-time quantitative PCR. The results showed that the gene was quickly induced (1 h) by the five heavy metals and the order of expression level was Hg>Pb>Cd>Cu>Zn. The induction effect of H(2)O(2) was 5-fold after about 15 min, but soon decreased to a non-significant level (30 min). The genetic diversity of Tetrahymena MT genes is discussed in relation to the unique structure of the Tpig-MT1 gene and other reported Cd-MT isoforms.
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Boldrin F, Santovito G, Formigari A, Bisharyan Y, Cassidy-Hanley D, Clark TG, Piccinni E. MTT2, a copper-inducible metallothionein gene from Tetrahymena thermophila. Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:232-40. [PMID: 18068524 DOI: 10.1016/j.cbpc.2007.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 10/11/2007] [Accepted: 10/11/2007] [Indexed: 11/27/2022]
Abstract
Metallothioneins (MTs) are ubiquitous, cysteine-rich, metal-binding proteins whose transcriptional activation is induced by a variety of stimuli, in particular heavy metals such as cadmium, copper and zinc. Here we describe the sequence and organization of a novel copper-inducible metallothionein gene (MTT2) from Tetrahymena thermophila. Based on its deduced sequence, the gene encodes a protein 108 amino acids, containing 29 cysteine residues (30%) arranged in motifs characteristic of vertebrate and invertebrate MTs. We demonstrate that the 5'-region of the MTT2 gene can act as an efficient promoter to drive the expression of heterologous genes in the Tetrahymena system. In the latter case, a gene for a candidate vaccine antigen against Ichthyophthirius multifiliis, a ubiquitous parasite of freshwater fish, was expressed at high levels in transformed T. thermophila cell lines. Moreover, the protein was properly folded and targeted to the plasma membrane in its correct three-dimensional conformation. This new copper-inducible MT promoter may be an attractive alternative to the cadmium-inducible MTT1 promoter for driving ectopic gene expression in Tetrahymena and could have a great impact on biotechnological perspectives.
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12
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Shuja RN, Shakoori AR. Identification and cloning of first cadmium metallothionein like gene from locally isolated ciliate, Paramecium sp. Mol Biol Rep 2008; 36:549-60. [PMID: 18273691 DOI: 10.1007/s11033-008-9213-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 01/25/2008] [Indexed: 11/30/2022]
Abstract
First cadmium metallothionein like gene PMCd1 of a ciliate, Paramecium sp., isolated from industrial wastewater has been cloned and sequenced. PMCd1 is an intronless gene, encoding 612 nucleotides, with TAA coding for glutamine. The coding region of PMCd1 comprises 203 amino acids, including 37 cysteine residues with a conserved structural pattern in the form of recurring structural motifs, arranged in 17 x-cys-x-y-cys-x, 1 x-cys-cys-x and x-cys-x contexts. Both, the deduced amino acids and nucleotide sequence differ, not only from other animal metallothioneins (MTs), but also from the previously characterized Tetrahymena Cu and Cd-MTs. The translated protein of PMCd1 contains conserved cysteine residues, peculiar characteristic of stress inducible metallothionein genes of ciliates and other groups of organisms.
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Zorita I, Bilbao E, Schad A, Cancio I, Soto M, Cajaraville MP. Tissue- and cell-specific expression of metallothionein genes in cadmium- and copper-exposed mussels analyzed by in situ hybridization and RT–PCR. Toxicol Appl Pharmacol 2007; 220:186-96. [PMID: 17350662 DOI: 10.1016/j.taap.2007.01.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 01/02/2007] [Accepted: 01/05/2007] [Indexed: 10/23/2022]
Abstract
Metallothioneins (MTs) are metal-inducible proteins that can be used as biomarkers of metal exposure. In mussels two families of MT isoforms (MT10 and MT20) have been characterized. In this study, mussels (Mytilus galloprovincialis) were exposed to 200 ppb Cd and 40 ppb Cu for 2 and 9 days to characterize the tissue and isoform specificity of metal-induced MT expression. Non-radioactive in situ hybridization demonstrated that both MT isoforms were mainly transcribed in digestive tubule epithelial cells, especially in basophilic cells. Weaker MT expression was detected in non-ciliated duct cells, stomach and gill epithelial cells, haemocytes, adipogranular cells, spermatic follicles and oocytes. RT-PCR resulted in cloning of a novel M. galloprovincialis isoform homologous to recently cloned Mytilus edulis intron-less MT10B isoform. In gills, Cd only affected MT10 gene expression after 2 days of exposure while increases in MT protein levels occurred at day 9. In the digestive gland, a marked increase of both isoforms, but especially of MT20, was accompanied by increased levels of MT proteins and basophilic cell volume density (Vv(BAS)) after 2 and 9 days and of intralysosomal metal accumulation in digestive cells after 9 days. Conversely, although metal was accumulated in digestive cells lysosomes and the Vv(BAS) increased in Cu-exposed mussels, Cu exposure did not produce an increase of MT gene expression or MT protein levels. These data suggest that MTs are expressed in a tissue-, cell- and isoform-specific way in response to different metals.
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Affiliation(s)
- I Zorita
- Lab. Cell Biology and Histology, Dept. Zoology and Animal Cell Biology, University of the Basque Country, PO Box 644, E-48080 Bilbao, Basque Country, Spain
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Kádár E. Postcapture depuration of essential metals in the deep sea hydrothermal mussel Bathymodiolus azoricus. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2007; 78:99-106. [PMID: 17401505 DOI: 10.1007/s00128-007-9073-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- E Kádár
- Department of Oceanography and Fisheries, IMAR Centre of the University of Azores, 9901-862 Horta, Portugal.
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Santovito G, Formigari A, Boldrin F, Piccinni E. Molecular and functional evolution of Tetrahymena metallothioneins: new insights into the gene family of Tetrahymena thermophila. Comp Biochem Physiol C Toxicol Pharmacol 2007; 144:391-7. [PMID: 17208053 DOI: 10.1016/j.cbpc.2006.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2006] [Revised: 11/23/2006] [Accepted: 11/23/2006] [Indexed: 11/26/2022]
Abstract
A new metallothionein (MTT-5) gene isoform has been cloned and characterized from the ciliate Tetrahymena thermophila. Its amino acid sequence shows only limited similarity with other Tetrahymena MTs. To investigate the transcriptional activity of this gene toward heavy metals (Cd, Cu, Zn), mRNA levels were evaluated by real-time quantitative PCR. Results show that the three metals induce different MTT-5-mRNA levels, Cd treatment eliciting the most effective induction in the first 30 min. Phylogenetic analyses of all Tetrahymena MT protein sequences revealed that MTT-5 is closely related to Cd-induced isoforms and quite separate from Cu-induced ones. Our results indicate that Cd and Cu MTs diverged early in evolution, before the speciation event which separated the Tetrahymena borealis group from the Tetrahymena australis group. The mutation rate in the Tetrahymena MT group is heterogeneous, being very low for MT-1 and MTT-1 and higher for the other isoforms, particularly for MTT-5, which shows the maximum divergence among the Cd-induced MTs. This observation, together with the evidence of its inducibility by Zn - a unique condition among T. thermophila MTs - indicates that MTT-5 underwent a particular evolutionary history, independent of other MT isoforms.
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Affiliation(s)
- Gianfranco Santovito
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
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Kádár E. Postcapture depuration of essential metals in the deep sea hydrothermal mussel Bathymodiolus azoricus. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2007; 78:45-52. [PMID: 17333424 DOI: 10.1007/s00128-007-9001-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- E Kádár
- Department of Oceanography and Fisheries, IMAR Centre of the University of Azores, 9901-862 Horta, Portugal.
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Hardivillier Y, Denis F, Demattei MV, Bustamante P, Laulier M, Cosson R. Metal influence on metallothionein synthesis in the hydrothermal vent mussel Bathymodiolus thermophilus. Comp Biochem Physiol C Toxicol Pharmacol 2006; 143:321-32. [PMID: 16735141 DOI: 10.1016/j.cbpc.2006.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 03/22/2006] [Accepted: 03/23/2006] [Indexed: 02/04/2023]
Abstract
The present study reports on the metallothionein expression in the hydrothermal vent mussel Bathymodiolus thermophilus. Metallothioneins (MT) are proteins involved in intracellular metal regulation and conserved throughout the animal kingdom. The hydrothermal vent environment presents peculiarities (high levels of sulfides and metals, low pH, anoxia) that may have driven associated species to develop original evolutionary ways to face these extreme living conditions. Mussels were exposed to different metal solutions at the atmospheric pressure. The MT mRNA levels and MT contents were measured in gills and mantles of each exposed mussel. The intracellular metal distribution was estimated in fractions obtained after the centrifugation of tissue homogenates. A few of the tested metals (Ag, Cu, Cd, Hg and Zn) were able to significantly induce MT mRNA levels. Silver was the only one that produced a significant increase of the MT protein level in both mantle and gills. The gills always presented higher MT protein levels than the mantle did, while their MT mRNA levels were similar. Our data show that MT mRNA and MT protein levels do not follow a clear relationship in the gills and mantle of B. thermophilus and we assume that a posttranscriptional control occurs in these mussels.
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Affiliation(s)
- Yann Hardivillier
- Laboratoire de Biologie et Génétique Evolutive, Université du Maine, Avenue Olivier Messiaen 72085 Le Mans, France.
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Fu C, Miao W. Cloning and Characterization of a New Multi-Stress Inducible Metallothionein Gene in Tetrahymena pyriformis. Protist 2006; 157:193-203. [PMID: 16621695 DOI: 10.1016/j.protis.2006.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 02/13/2006] [Indexed: 10/24/2022]
Abstract
A new multi-stress-inducible metallothionein (MT) gene isoform has been cloned and characterized from the ciliate Tetrahymena pyriformis. Both the 5'- and 3'-UT regions of the Tp-MT2 gene are very different from the previously reported Tp-MT1 isoform in this organism and from other described MT genes in Tetrahymena pigmentosa and Tetrahymena thermophila. The putative protein sequence of Tp-MT2 contains cysteine clusters with characteristics of the typical Tetrahymena Cd-inducible MT genes. However, the sequence has a special feature of four intragenic tandem repeats within its first half, with a conserved structural pattern x(5/8)CCCx(6)CCx(6)CxCxNCxCCK. To investigate the transcriptional activities of both Tp-MT2 and Tp-MT1 genes toward heavy metals (Cd, Hg, Cu, Zn) and H(2)O(2), the mRNA levels of these two isoforms were evaluated by means of real-time quantitative PCR. Results showed that Tp-MT2 had a higher basal expression level than Tp-MT1 and both genes were induced by Cd, Hg, Cu, and Zn ions after short exposure (1h), although to different extents. Cd was the most effective metal inducer of both two isoforms, but the relative expression level of Tp-MT2 was much lower than that of Tp-MT1. Different expression patterns were also shown between the two genes when treated with Cd over a period of 24h. We suggest that TpMT-1 plays the role of a multi-inducible stress gene, while TpMT-2 may have a more specific function in basal metal homeostasis although it may have undergone a functional differentiation process. The putative functional significance and evolutionary mode of the TpMT-2 isoform are discussed.
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Affiliation(s)
- Chengjie Fu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
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Leignel V, Laulier M. Isolation and characterization of Mytilus edulis metallothionein genes. Comp Biochem Physiol C Toxicol Pharmacol 2006; 142:12-8. [PMID: 16326142 DOI: 10.1016/j.cbpc.2005.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Revised: 06/23/2005] [Accepted: 09/10/2005] [Indexed: 11/21/2022]
Abstract
Metallothioneins (MTs) are crucial proteins in all organisms for the regulation of essential metals and the detoxification of heavy metals. Many studies have estimated MT levels in mussel tissues to detect marine metal pollution. In this study, we investigated the MT gene structures of the forms present in Mytilus edulis (blue mussel). One MT-10 (2413 bp) gene and one MT-20 (1906 bp) gene were obtained. These MT genes contain three exons and two long introns. The splicing signals for MT-10 and MT-20 were GTA(T/A)GT-(C/T)AG. The structural organization (length of intron, splicing signals, AT content) of MT-10 and MT-20 is compared with other MT genes.
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Affiliation(s)
- Vincent Leignel
- Laboratoire de Biologie et Génétique évolutive, Université du Maine, France.
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