1
|
Dallinger R. Metals and metallothionein evolution in snails: a contribution to the concept of metal-specific functionality from an animal model group. Biometals 2024; 37:671-696. [PMID: 38416244 PMCID: PMC11101346 DOI: 10.1007/s10534-024-00584-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/10/2024] [Indexed: 02/29/2024]
Abstract
This is a critical review of what we know so far about the evolution of metallothioneins (MTs) in Gastropoda (snails, whelks, limpets and slugs), an important class of molluscs with over 90,000 known species. Particular attention will be paid to the evolution of snail MTs in relation to the role of some metallic trace elements (cadmium, zinc and copper) and their interaction with MTs, also compared to MTs from other animal phyla. The article also highlights the important distinction, yet close relationship, between the structural and metal-selective binding properties of gastropod MTs and their physiological functionality in the living organism. It appears that in the course of the evolution of Gastropoda, the trace metal cadmium (Cd) must have played an essential role in the development of Cd-selective MT variants. It is shown how the structures and Cd-selective binding properties in the basal gastropod clades have evolved by testing and optimizing different combinations of ancestral and novel MT domains, and how some of these domains have become established in modern and recent gastropod clades. In this context, the question of how adaptation to new habitats and lifestyles has affected the original MT traits in different gastropod lineages will also be addressed. The 3D structures and their metal binding preferences will be highlighted exemplarily in MTs of modern littorinid and helicid snails. Finally, the importance of the different metal requirements and pathways in snail tissues and cells for the shaping and functionality of the respective MT isoforms will be shown.
Collapse
|
2
|
Abd-El-Haleem D. AraC transcriptional regulator, aspartate semialdehyde dehydrogenase and acyltransferase: Three putative genes in phenol catabolic pathway of Acinetobacter sp. Strain DF4. J Genet Eng Biotechnol 2024; 22:100349. [PMID: 38494254 PMCID: PMC10980861 DOI: 10.1016/j.jgeb.2023.100349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 12/03/2023] [Indexed: 03/19/2024]
Abstract
The objective of this study was to identify genes associated with the biodegradation of phenol by Acinetobacter sp. strain DF4 through the use of differential display (DD) methodology. The bacteria were grown in YEPG medium, and total RNA was extracted and analyzed using labeled primers to detect gene expression differences. Three distinctively expressed cDNA bands (ph1, ph2, and ph3) were identified, cloned, and sequenced. DNA analysis involved searching for open reading frames (ORFs), verifying results with the NCBI database, predicting promoter regions, and constructing phylogenetic trees using bioinformatics tools. The ph1 gene displayed a 97% identity with the AraC transcriptional regulator, suggesting its potential role in regulating the ortho-catabolic pathway of phenol. The ph2 gene showed a 98% identity with aspartate semialdehyde dehydrogenase, which is involved in phenol degradation. The ph3 gene had a 93% identity with acetyltransferase. Essential transcription factors, such as TATA, GTGTGT, CACA, and CTTTT, were detected, and the three genes promoter regions were predicted. This study successfully identified functional genes involved in the metabolism of cyclic chemicals, particularly phenol, using the DD technique. These findings provide insights into the biodegradation pathways of phenol by Acinetobacter sp. Strain DF4 and may contribute to the development of more efficient bioremediation strategies for phenol-contaminated environments.
Collapse
Affiliation(s)
- Desouky Abd-El-Haleem
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Institute, City of Scientific Research and Technological Applications, Burgelarab, Alexandria, Egypt.
| |
Collapse
|
3
|
Valsecchi R, Baumann C, Lila A, Zerbe O. Evolution of Cd2+ and Cu+ binding in Helix pomatia metallothioneins. Metallomics 2023; 15:mfad057. [PMID: 37738453 PMCID: PMC10548783 DOI: 10.1093/mtomcs/mfad057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/14/2023] [Indexed: 09/24/2023]
Abstract
Metallothioneins (MTs) are small proteins present in all kingdoms of life. Their high cysteine content enables them to bind metal ions, such as Zn2+, Cd2+, and Cu+, providing means for detoxification and metal homeostasis. Three MT isoforms with distinct metal binding preferences are present in the Roman Snail Helix pomatia. Here, we use nuclear magnetic resonance (NMR) to follow the evolution of Cd2+ and Cu+ binding from the reconstructed ancestral Stylommatophora MT to the three H. pomatia MT (HpMT) isoforms. Information obtained from [15N,1H]-HSQC spectra and T2 relaxation times are combined to describe the conformational stability of the MT-metal complexes. A well-behaved MT-metal complex adopts a unique structure and does not undergo additional conformational exchange. The ancestor to all three HpMTs forms conformationally stable Cd2+ complexes and closely resembles the Cd2+-specific HpCdMT isoform, suggesting a role in Cd2+ detoxification for the ancestral protein. All Cu+-MT complexes, including the Cu+-specific HpCuMT isoform, undergo a considerable amount of conformational exchange. The unspecific HpCd/CuMT and the Cu+-specific HpCuMT isoforms form Cu+ complexes with comparable characteristics. It is possible to follow how Cd2+ and Cu+ binding changed throughout evolution. Interestingly, Cu+ binding improved independently in the lineages leading to the unspecific and the Cu+-specific HpMT isoforms. C-terminal domains are generally less capable of coordinating the non-cognate metal ion than N-terminal domains, indicating a higher level of specialization of the C-domain. Our findings provide new insights into snail MT evolution, helping to understand the interplay between biological function and structural features toward a comprehensive understanding of metal preference.
Collapse
Affiliation(s)
- Renato Valsecchi
- Department of Chemistry, University of Zurich, 8057 Zurich, Winterthurerstrasse 190, Switzerland
| | - Christian Baumann
- Department of Chemistry, University of Zurich, 8057 Zurich, Winterthurerstrasse 190, Switzerland
| | - Ardit Lila
- Department of Chemistry, University of Zurich, 8057 Zurich, Winterthurerstrasse 190, Switzerland
| | - Oliver Zerbe
- Department of Chemistry, University of Zurich, 8057 Zurich, Winterthurerstrasse 190, Switzerland
| |
Collapse
|
4
|
Ke J, Zhang DG, Liu SZ, Luo Z. Functional analysis of selenok, selenot and selenop promoters and their regulation by selenium in yellow catfish Pelteobagrus fulvidraco. Gene 2023; 873:147461. [PMID: 37149273 DOI: 10.1016/j.gene.2023.147461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/25/2023] [Accepted: 05/01/2023] [Indexed: 05/08/2023]
Abstract
The selenok, selenot and selenop are three key selenoproteins involved in stress response. Our study, using the yellow catfish Pelteobagrus fulvidraco as the experimental animal, obtained the 1993-bp, 2000-bp and 1959-bp sequences of selenok, selenot and selenop promoters, respectively, and predicted the binding sites of several transcriptional factors on their promoters, such as Forkhead box O 4 (FoxO4), activating transcription factor 4 (ATF4), Kruppel-like factor 4 (KLF4) and nuclear factor erythroid 2-related factor 2 (NRF2). Selenium (Se) increased the activities of the selenok, selenot and selenop promoters. FoxO4 and Nrf2 can directly bind with selenok promoter and controlled selenok promoter activities positively; KLF4 and Nrf2 can directly bind with selenot promoter and controlled selenot promoter activities positively; FoxO4 and ATF4 can directly bind to selenop promoter and regulated selenop promoter activities positively. Se promoted FoxO4 and Nrf2 binding to selenok promoter, KLF4 and Nrf2 binding to selenot promoter, and FoxO4 and ATF4 binding to selenop promoter. Thus, we provide the first evidence for FoxO4 and Nrf2 bindnig elements in selenok promoter, KLF4 and Nrf2 binding elements in selenot promoter, and FoxO4 and ATF4 binding elements in selenop promoter, and offer novel insight into regulatory mechanism of these selenoproteins induced by Se.
Collapse
Affiliation(s)
- Jiang Ke
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Dian-Guang Zhang
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Sheng-Zan Liu
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Zhi Luo
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China; Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
| |
Collapse
|
5
|
García-Risco M, Calatayud S, Pedrini-Martha V, Albalat R, Dallinger R, Palacios Ò, Capdevila M. Metal-Specificity Divergence between Metallothioneins of Nerita peloronta (Neritimorpha, Gastropoda) Sets the Starting Point for a Novel Chemical MT Classification Proposal. Int J Mol Sci 2021; 22:13114. [PMID: 34884919 PMCID: PMC8658704 DOI: 10.3390/ijms222313114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/27/2021] [Accepted: 12/02/2021] [Indexed: 11/29/2022] Open
Abstract
Metallothioneins' (MTs) biological function has been a matter of debate since their discovery. The importance to categorize these cysteine-rich proteins with high coordinating capacity into a specific group led to numerous classification proposals. We proposed a classification based on their metal-binding abilities, gradually sorting them from those with high selectivity towards Zn/Cd to those that are Cu-specific. However, the study of the NpeMT1 and NpeMT2isoforms of Nerita peloronta, has put a new perspective on this classification. N. peloronta has been chosen as a representative mollusk to elucidate the metal-binding abilities of Neritimorpha MTs, an order without any MTs characterized recently. Both isoforms have been recombinantly synthesized in cultures supplemented with ZnII, CdII, or CuII, and the purified metal-MT complexes have been thoroughly characterized by spectroscopic and spectrometric methods, leading to results that confirmed that Neritimorpha share Cd-selective MTs with Caenogastropoda and Heterobranchia, solving a so far unresolved question. NpeMTs show high coordinating preferences towards divalent metal ions, although one of them (NpeMT1) shares features with the so-called genuine Zn-thioneins, while the other (NpeMT2) exhibits a higher preference for Cd. The dissimilarities between the two isoforms let a window open to a new proposal of chemical MT classification.
Collapse
Affiliation(s)
- Mario García-Risco
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain; (M.G.-R.); (Ò.P.)
| | - Sara Calatayud
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain; (S.C.); (R.A.)
| | - Veronika Pedrini-Martha
- Institute of Zoology and Center of Molecular Biosciences, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria;
| | - Ricard Albalat
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain; (S.C.); (R.A.)
| | - Reinhard Dallinger
- Institute of Zoology and Center of Molecular Biosciences, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria;
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain; (M.G.-R.); (Ò.P.)
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain; (M.G.-R.); (Ò.P.)
| |
Collapse
|
6
|
Effects of Cadmium Sulfate on the Brown Garden Snail Cornu aspersum: Implications for DNA Methylation. TOXICS 2021; 9:toxics9110306. [PMID: 34822697 PMCID: PMC8619149 DOI: 10.3390/toxics9110306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 11/16/2022]
Abstract
An extensive literature exists regarding the cellular, physiological, and genetic effects of cadmium (Cd)—A highly toxic, but commonly used trace metal in modern industry. However, limited data are available on its epigenetic effects, especially for terrestrial sentinel invertebrates. We determined Cd retention, total DNA methylation, and the methylation status of 5′ end of the Cd-MT gene in the hepatopancreas of the brown garden snail, Cornu aspersum, fed Cd sulfate for four weeks. Bodyweight changes and survival were also measured. Hepatopancreas cadmium increased in a dose-dependent manner from the third-lowest dose onward, with very large amounts being found for the highest treatment group. However, no mortalities occurred, irrespective of dietary Cd dose. We identified significant genome-wide hypermethylation in specimens given the highest dose, which overlapped with a significant bodyweight decrease. The Cd-MT gene showed an unmethylated 5′ end of the Cd-MT gene and this status was not affected by cadmium exposure. Hepatopancreas DNA methylation is as sensitive as bodyweight to non-lethal concentrations of dietary Cd given as cadmium sulfate but less responsive than tissue accumulation. Such an exposure event, by contrast, does not affect the methylation status of the Cd-MT gene 5′ end.
Collapse
|
7
|
Zebrafish (Danio rerio) ecotoxicological ABCB4, ABCC1 and ABCG2a gene promoters depict spatiotemporal xenobiotic multidrug resistance properties against environmental pollutants. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101110] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
8
|
Breitwieser M, Bruneau M, Barbarin M, Churlaud C, Mouneyrac C, Thomas H. Is metallothionein in Mimachlamys varia a suitable biomarker of trace elements in the waters of the French Atlantic coast? ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:20259-20272. [PMID: 32240510 DOI: 10.1007/s11356-020-08392-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 03/11/2020] [Indexed: 06/11/2023]
Abstract
The development of human activities along the Atlantic coast is responsible for the chronic pollution of the environment with organic and inorganic contaminants. In recent years, environmental regulations such as the MSFD (2008/56/EC) and the OSPAR commission have been developed to preserve coastal environments, giving rise to studies in aquatic biomonitoring. One of them is to use biomarkers to observe the pollutants impact on coastal species such as the bivalve Mimachlamys varia. A defence biomarker was considered in this research to study metal accumulation, with metallothioneins (Mts) involved in the uptake, storage and excretion of metals. To achieve this, bivalves were collected in March 2016 in seven sites along the French Atlantic coasts (open area) and in harbours (semi-open area) with contrasting levels of pollution. Biomarker assays were performed to compare the responses in several tissues (digestive glands, gonads, gills) to inorganic pollutants. The results showed that the accumulation of trace element was different depending on the site and the organ. Mts concentrations were greater in digestive gland compared with gills. Usually, Mts levels were decreased in site showing elevated levels of trace element which explained by downregulation of Mts. Furthermore, results of correlation between Mts and inorganic contaminants and the influence of abiotic factors on Mts suggested that Mts in M. varia is not a relevant biomarker in environments exposed to cocktails of contaminants.
Collapse
Affiliation(s)
- Marine Breitwieser
- Littoral Environnement & Sociétés (LIENSs) UMR 7266 CNRS, 2 rue Olympe de Gouges, 17000, La Rochelle, France.
| | - Mélanie Bruneau
- Mer, Molécules, Santé (MMS, EA2160), Université Catholique de l'Ouest (UCO), 3 place André Leroy, 49000, Angers, France
| | - Marine Barbarin
- Littoral Environnement & Sociétés (LIENSs) UMR 7266 CNRS, 2 rue Olympe de Gouges, 17000, La Rochelle, France
| | - Carine Churlaud
- Littoral Environnement & Sociétés (LIENSs) UMR 7266 CNRS, 2 rue Olympe de Gouges, 17000, La Rochelle, France
| | - Catherine Mouneyrac
- Mer, Molécules, Santé (MMS, EA2160), Université Catholique de l'Ouest (UCO), 3 place André Leroy, 49000, Angers, France
| | - Hélène Thomas
- Littoral Environnement & Sociétés (LIENSs) UMR 7266 CNRS, 2 rue Olympe de Gouges, 17000, La Rochelle, France
| |
Collapse
|
9
|
Chen GH, Lv W, Xu YH, Wei XL, Xu YC, Luo Z. Functional analysis of MTF-1 and MT promoters and their transcriptional response to zinc (Zn) and copper (Cu) in yellow catfish Pelteobagrus fulvidraco. CHEMOSPHERE 2020; 246:125792. [PMID: 31918101 DOI: 10.1016/j.chemosphere.2019.125792] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/27/2019] [Accepted: 12/29/2019] [Indexed: 06/10/2023]
Abstract
Metal-responsive transcription factor-1 (MTF-1) and metallothionein (MT) expression are involved in metal homeostasis and detoxification. Here, we characterized the structure and functions of mtf-1 and mt promoters in yellow catfish Pelteobagrus fulvidraco. Many important binding sites of transcriptional factors, such as heat shock promoter element (HSE) and metal responsive element (MRE), were predicted on their promoter regions. Cu did not significantly influence the activity of mtf-1 promoter, but Zn increased its promoter activity. Cu and Zn induced the increase of mt promoter activity. HSE site of mtf-1 promoter was the functional binding locus responsible for Zn-induced mtf-1 transcriptional activation. Zn and Cu induced transcriptional activation of mt gene through the MTF-1- and MRE-dependent pathway. Using primary hepatocytes of yellow catfish, we found that Cu and Zn induced the mt expression; Cu did not significantly influence the mRNA and total protein levels of MTF-1, but Zn up-regulated its mRNA and total protein expression. Both Zn and Cu treatment also up-regulated MTF-1 nuclear protein expression, which in turn increased the mt expression. Taken together, these findings delineated the transcriptional regulation of MT and MTF-1 under Zn or Cu treatments, and provided some mechanisms for the regulation of Cu and Zn homeostasis in vertebrates.
Collapse
Affiliation(s)
- Guang-Hui Chen
- Laboratory of Molecular Nutrition for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wuhong Lv
- Laboratory of Molecular Nutrition for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yi-Huan Xu
- Laboratory of Molecular Nutrition for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiao-Lei Wei
- Laboratory of Molecular Nutrition for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yi-Chuang Xu
- Laboratory of Molecular Nutrition for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhi Luo
- Laboratory of Molecular Nutrition for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan, 430070, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
| |
Collapse
|
10
|
Cadmium Uptake, MT Gene Activation and Structure of Large-Sized Multi-Domain Metallothioneins in the Terrestrial Door Snail Alinda biplicata (Gastropoda, Clausiliidae). Int J Mol Sci 2020; 21:ijms21051631. [PMID: 32120996 PMCID: PMC7084494 DOI: 10.3390/ijms21051631] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 02/06/2023] Open
Abstract
Terrestrial snails (Gastropoda) possess Cd-selective metallothioneins (CdMTs) that inactivate Cd2+ with high affinity. Most of these MTs are small Cysteine-rich proteins that bind 6 Cd2+ equivalents within two distinct metal-binding domains, with a binding stoichiometry of 3 Cd2+ ions per domain. Recently, unusually large, so-called multi-domain MTs (md-MTs) were discovered in the terrestrial door snail Alinda biplicata (A.b.). The aim of this study is to evaluate the ability of A.b. to cope with Cd stress and the potential involvement of md-MTs in its detoxification. Snails were exposed to increasing Cd concentrations, and Cd-tissue concentrations were quantified. The gene structure of two md-MTs (9md-MT and 10md-MT) was characterized, and the impact of Cd exposure on MT gene transcription was quantified via qRT PCR. A.b. efficiently accumulates Cd at moderately elevated concentrations in the feed, but avoids food uptake at excessively high Cd levels. The structure and expression of the long md-MT genes of A.b. were characterized. Although both genes are intronless, they are still transcribed, being significantly upregulated upon Cd exposure. Overall, our results contribute new knowledge regarding the metal handling of Alinda biplicata in particular, and the potential role of md-MTs in Cd detoxification of terrestrial snails, in general.
Collapse
|
11
|
Dvorak M, Schnegg R, Niederwanger M, Pedrini-Martha V, Ladurner P, Lindner H, Kremser L, Lackner R, Dallinger R. Cadmium Pathways in Snails Follow a Complementary Strategy between Metallothionein Detoxification and Auxiliary Inactivation by Phytochelatins. Int J Mol Sci 2019; 21:ijms21010007. [PMID: 31861343 PMCID: PMC6981842 DOI: 10.3390/ijms21010007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/02/2019] [Accepted: 12/14/2019] [Indexed: 11/16/2022] Open
Abstract
Metal detoxification is crucial for animals to cope with environmental exposure. In snails, a pivotal role in protection against cadmium (Cd) is attributed to metallothioneins (MTs). Some gastropod species express, in a lineage-specific manner, Cd-selective MTs devoted exclusively to the binding and detoxification of this single metal, whereas other species of snails possess non-selective MTs, but still show a high tolerance against Cd. An explanation for this may be that invertebrates and in particular snails may also synthetize phytochelatins (PCs), originally known to be produced by plants, to provide protection against metal or metalloid toxicity. Here we demonstrate that despite the fact that similar mechanisms for Cd inactivation exist in snail species through binding of the metal to MTs, the actual detoxification pathways for this metal may follow different traits in a species-specific manner. In particular, this depends on the detoxification capacity of MTs due to their Cd-selective or non-specific binding features. In the terrestrial slug Arion vulgaris, for example, Cd is solely detoxified by a Cd-selective MT isoform (AvMT1). In contrast, the freshwater snail Biomphalaria glabrata activates an additional pathway for metal inactivation by synthesizing phytochelatins, which compensate for the insufficient capacity of its non-selective MT system to detoxify Cd. We hypothesize that in other snails and invertebrate species, too, an alternative inactivation of the metal by PCs may occur, if their MT system is not Cd-selective enough, or its Cd loading capacity is exhausted.
Collapse
Affiliation(s)
- Martin Dvorak
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Raimund Schnegg
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Michael Niederwanger
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Veronika Pedrini-Martha
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Peter Ladurner
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Herbert Lindner
- Institute of Clinical Biochemistry, Innsbruck Medical University, Biocenter, Innrain 80, A-6020 Innsbruck, Austria
| | - Leopold Kremser
- Institute of Clinical Biochemistry, Innsbruck Medical University, Biocenter, Innrain 80, A-6020 Innsbruck, Austria
| | - Reinhard Lackner
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Correspondence: (R.L.); (R.D.)
| | - Reinhard Dallinger
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Correspondence: (R.L.); (R.D.)
| |
Collapse
|
12
|
Drechsel V, Fiechtner B, Höckner M. Promoter activity of earthworm metallothionein in mouse embryonic fibroblasts. Mol Biol Rep 2019; 46:6371-6379. [PMID: 31571111 DOI: 10.1007/s11033-019-05082-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 09/14/2019] [Indexed: 10/25/2022]
Abstract
The regulation of metallothionein (MT) gene expression as important part of the detoxification machinery is only scarcely known in invertebrates. In vertebrates, MT gene activation is mediated by the metal-transcription factor 1 (MTF-1) binding to metal response elements (MREs). In invertebrates, the mechanisms of MT gene activation seems to be more diverse. In some invertebrate species, MTF-1 orthologues as well as their ability to activate MT genes via MREs have been uncovered. Although earthworm MTs have been well studied, a MTF-1 orthologue has not yet been described and MT gene activation mechanisms are largely unknown. Analyses of the earthworm wMT2 promoter by reporter gene assays have been performed. We could show that the wMT2 promoter was active in mouse embryonic fibroblasts (NIH/3T3) as well as in mouse MTF-1-/-cells (DKO7). The presence of mouse MTF-1 (mMTF1) led to a significant increase in reporter gene activity. We observed that cadmium as well as zinc had an effect on promoter activity. In the presence of zinc, promoter activity doubled in NIH cells, however, we did not observe a significant effect in the DKO7 cell line. Cadmium decreased promoter activity in DKO7 cells, but this effect could be reversed by providing mMTF1 in a co-transfection experiment. We suggest that MT gene expression in the earthworm is not entirely dependent on a MRE binding protein. Interestingly, the shortest promoter fragment including MRE1 showed the highest promoter activity under control conditions.
Collapse
Affiliation(s)
- Victoria Drechsel
- Institute of Zoology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Birgit Fiechtner
- Institute of Zoology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Martina Höckner
- Institute of Zoology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
| |
Collapse
|
13
|
Beil A, Jurt S, Walser R, Schönhut T, Güntert P, Palacios Ò, Atrian S, Capdevila M, Dallinger R, Zerbe O. The Solution Structure and Dynamics of Cd-Metallothionein from Helix pomatia Reveal Optimization for Binding Cd over Zn. Biochemistry 2019; 58:4570-4581. [DOI: 10.1021/acs.biochem.9b00830] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrea Beil
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Simon Jurt
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Reto Walser
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Tanja Schönhut
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Peter Güntert
- Institute of Biophysical Chemistry, Goethe-University Frankfurt am Main, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Òscar Palacios
- Departmento de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Silvia Atrian
- Departmento de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, E-08028 Barcelona, Spain
| | - Mercè Capdevila
- Departmento de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Reinhard Dallinger
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Oliver Zerbe
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| |
Collapse
|
14
|
Calatayud S, Garcia-Risco M, Rojas NS, Espinosa-Sánchez L, Artime S, Palacios Ò, Cañestro C, Albalat R. Metallothioneins of the urochordate Oikopleura dioica have Cys-rich tandem repeats, large size and cadmium-binding preference. Metallomics 2018; 10:1585-1594. [DOI: 10.1039/c8mt00177d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oikopleura dioica has the longest metallothionein described so far, made of repeats generated by a modular and step-wise evolution.
Collapse
Affiliation(s)
- Sara Calatayud
- Departament de Genètica
- Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio)
- Facultat de Biologia
- Universitat de Barcelona
- Barcelona
| | - Mario Garcia-Risco
- Departament de Química
- Facultat de Ciències
- Universitat Autònoma de Barcelona
- E-08193 Cerdanyola del Vallès
- Spain
| | - Natalia S. Rojas
- Departament de Genètica
- Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio)
- Facultat de Biologia
- Universitat de Barcelona
- Barcelona
| | - Lizethe Espinosa-Sánchez
- Departament de Genètica
- Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio)
- Facultat de Biologia
- Universitat de Barcelona
- Barcelona
| | - Sebastián Artime
- Departament de Genètica
- Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio)
- Facultat de Biologia
- Universitat de Barcelona
- Barcelona
| | - Òscar Palacios
- Departament de Química
- Facultat de Ciències
- Universitat Autònoma de Barcelona
- E-08193 Cerdanyola del Vallès
- Spain
| | - Cristian Cañestro
- Departament de Genètica
- Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio)
- Facultat de Biologia
- Universitat de Barcelona
- Barcelona
| | - Ricard Albalat
- Departament de Genètica
- Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio)
- Facultat de Biologia
- Universitat de Barcelona
- Barcelona
| |
Collapse
|
15
|
Pedrini-Martha V, Schnegg R, Baurand PE, deVaufleury A, Dallinger R. The physiological role and toxicological significance of the non-metal-selective cadmium/copper-metallothionein isoform differ between embryonic and adult helicid snails. Comp Biochem Physiol C Toxicol Pharmacol 2017; 199:38-47. [PMID: 28254493 DOI: 10.1016/j.cbpc.2017.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/16/2017] [Accepted: 02/16/2017] [Indexed: 11/20/2022]
Abstract
Metal regulation is essential for terrestrial gastropods to survive. In helicid snails, two metal-selective metallothionein (MT) isoforms with different functions are expressed. A cadmium-selective isoform (CdMT) plays a major role in Cd2+ detoxification and stress response, whereas a copper-selective MT (CuMT) is involved in Cu homeostasis and hemocyanin synthesis. A third, non-metal-selective isoform, called Cd/CuMT, was first characterized in Cantareus aspersus. The aim of this study was to quantify the transcriptional activity of all three MT genes in unexposed and metal-exposed (Cd, Cu) embryonic Roman snails. In addition, the complete Cd/CuMT mRNA of the Roman snail (Helix pomatia) was characterized, and its expression quantified in unexposed and Cd-treated adult individuals. In embryos of Helix pomatia, the Cd/CuMT gene was induced upon Cu exposure. Its transcription levels were many times higher than that of the other two MT genes, and also exceeded by far the Cd/CuMT mRNA concentrations of adult snails. In the hepatopancreas of adult Roman snails, no Cd/CuMT could be detected at the protein level, irrespective of whether the snails had been exposed to Cd or not. This contrasts with the situation in the near relative, Cantareus aspersus. It appeared that the 3'-UTR of the Cd/CuMT mRNA differed largely between Cantareus aspersus and Helix pomatia, being larger in the latter species, with a number of putative binding sites for proteins and miRNAs known to inhibit mRNA translation. We suggest this as a possible mechanism responsible for the lack of Cd/CuMT protein expression in adult Roman snails.
Collapse
Affiliation(s)
| | - Raimund Schnegg
- Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Pierre-Emmanuel Baurand
- Chrono-Environnement, UMR 6249 University of Franche-Comté, 16 route de Gray, 25030 Besançon cedex, France
| | - Annette deVaufleury
- Chrono-Environnement, UMR 6249 University of Franche-Comté, 16 route de Gray, 25030 Besançon cedex, France; Department of Health Safety Environment, avenue des Rives du Lac, BP179, 70003 Vesoul cedex, France
| | - Reinhard Dallinger
- Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
| |
Collapse
|
16
|
Niederwanger M, Dvorak M, Schnegg R, Pedrini-Martha V, Bacher K, Bidoli M, Dallinger R. Challenging the Metallothionein (MT) Gene of Biomphalaria glabrata: Unexpected Response Patterns Due to Cadmium Exposure and Temperature Stress. Int J Mol Sci 2017; 18:E1747. [PMID: 28800079 PMCID: PMC5578137 DOI: 10.3390/ijms18081747] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/03/2017] [Accepted: 08/07/2017] [Indexed: 02/04/2023] Open
Abstract
Metallothioneins (MTs) are low-molecular-mass, cysteine-rich, metal binding proteins. In most animal species, they are involved in metal homeostasis and detoxification, and provide protection from oxidative stress. Gastropod MTs are highly diversified, exhibiting unique features and adaptations like metal specificity and multiplications of their metal binding domains. Here, we show that the MT gene of Biomphalaria glabrata, one of the largest MT genes identified so far, is composed in a unique way. The encoding for an MT protein has a three-domain structure and a C-terminal, Cys-rich extension. Using a bioinformatic approach involving structural and in silico analysis of putative transcription factor binding sites (TFBs), we found that this MT gene consists of five exons and four introns. It exhibits a regulatory promoter region containing three metal-responsive elements (MREs) and several TFBs with putative involvement in environmental stress response, and regulation of gene expression. Quantitative real-time polymerase chain reaction (qRT-PCR) data indicate that the MT gene is not inducible by cadmium (Cd) nor by temperature challenges (heat and cold), despite significant Cd uptake within the midgut gland and the high Cd tolerance of metal-exposed snails.
Collapse
Affiliation(s)
- Michael Niederwanger
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Martin Dvorak
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Raimund Schnegg
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Veronika Pedrini-Martha
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Katharina Bacher
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Massimo Bidoli
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Reinhard Dallinger
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| |
Collapse
|
17
|
Baumann C, Beil A, Jurt S, Niederwanger M, Palacios O, Capdevila M, Atrian S, Dallinger R, Zerbe O. Strukturanpassung eines Proteins an Metallbelastung: NMR-Struktur eines marinen Schnecken-Metallothioneins mit einer zusätzlichen Domäne. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Christian Baumann
- Institut für Chemie; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Schweiz
| | - Andrea Beil
- Institut für Chemie; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Schweiz
| | - Simon Jurt
- Institut für Chemie; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Schweiz
| | - Michael Niederwanger
- Institut für Zoologie und Forschungsschwerpunkt für Molekulare Biowissenschaften; Universität Innsbruck; Technikerstraße 25 6020 Innsbruck Österreich
| | - Oscar Palacios
- Departament de Química; Universitat Autònoma de Barcelona; Spanien
| | - Mercè Capdevila
- Departament de Química; Universitat Autònoma de Barcelona; Spanien
| | - Sílvia Atrian
- Department of Genetics, Microbiology and Statistics; Faculty of Biology; University of Barcelona; Spanien
| | - Reinhard Dallinger
- Institut für Zoologie und Forschungsschwerpunkt für Molekulare Biowissenschaften; Universität Innsbruck; Technikerstraße 25 6020 Innsbruck Österreich
| | - Oliver Zerbe
- Institut für Chemie; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Schweiz
| |
Collapse
|
18
|
Baumann C, Beil A, Jurt S, Niederwanger M, Palacios O, Capdevila M, Atrian S, Dallinger R, Zerbe O. Structural Adaptation of a Protein to Increased Metal Stress: NMR Structure of a Marine Snail Metallothionein with an Additional Domain. Angew Chem Int Ed Engl 2017; 56:4617-4622. [DOI: 10.1002/anie.201611873] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/03/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Christian Baumann
- Department of Chemistry; University of Zurich; Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Andrea Beil
- Department of Chemistry; University of Zurich; Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Simon Jurt
- Department of Chemistry; University of Zurich; Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Michael Niederwanger
- Institute of Zoology and Center for Molecular Biosciences; University of Innsbruck; Technikerstrasse 25 6020 Innsbruck Austria
| | - Oscar Palacios
- Departament de Química; Universitat Autònoma de Barcelona; 08193 Cerdanyola del Vallès Barcelona Spain
| | - Mercè Capdevila
- Departament de Química; Universitat Autònoma de Barcelona; 08193 Cerdanyola del Vallès Barcelona Spain
| | - Sílvia Atrian
- Department of Genetics, Microbiology and Statistics; Faculty of Biology; University of Barcelona; Av. Diagonal 643 08028 Barcelona Spain
| | - Reinhard Dallinger
- Institute of Zoology and Center for Molecular Biosciences; University of Innsbruck; Technikerstrasse 25 6020 Innsbruck Austria
| | - Oliver Zerbe
- Department of Chemistry; University of Zurich; Winterthurerstrasse 190 8057 Zurich Switzerland
| |
Collapse
|
19
|
Pedrini-Martha V, Niederwanger M, Kopp R, Schnegg R, Dallinger R. Physiological, Diurnal and Stress-Related Variability of Cadmium-Metallothionein Gene Expression in Land Snails. PLoS One 2016; 11:e0150442. [PMID: 26935042 PMCID: PMC4774997 DOI: 10.1371/journal.pone.0150442] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/15/2016] [Indexed: 12/04/2022] Open
Abstract
The terrestrial Roman snail Helix pomatia has successfully adapted to strongly fluctuating conditions in its natural soil habitat. Part of the snail’s stress defense strategy is its ability to express Metallothioneins (MTs). These are multifunctional, cysteine-rich proteins that bind and inactivate transition metal ions (Cd2+, Zn2+, Cu+) with high affinity. In Helix pomatia a Cadmium (Cd)-selective, inducible Metallothionein Isoform (CdMT) is mainly involved in detoxification of this harmful metal. In addition, the snail CdMT has been shown to also respond to certain physiological stressors. The aim of the present study was to investigate the physiological and diurnal variability of CdMT gene expression in snails exposed to Cd and non-metallic stressors such as desiccation and oxygen depletion. CdMT gene expression was upregulated by Cd exposure and desiccation, whereas no significant impact on the expression of CdMT was measured due to oxygen depletion. Overall, Cd was clearly more effective as an inducer of the CdMT gene expression compared to the applied non-metallic stressors. In unexposed snails, diurnal rhythmicity of CdMT gene expression was observed with higher mRNA concentrations at night compared to daytime. This rhythmicity was severely disrupted in Cd-exposed snails which exhibited highest CdMT gene transcription rates in the morning. Apart from diurnal rhythmicity, feeding activity also had a strong impact on CdMT gene expression. Although underlying mechanisms are not completely understood, it is clear that factors increasing MT expression variability have to be considered when using MT mRNA quantification as a biomarker for environmental stressors.
Collapse
Affiliation(s)
- Veronika Pedrini-Martha
- Department of Ecophysiology, Division of Zoology, University of Innsbruck, Innsbruck, Tirol, Austria
- * E-mail: (RD); (VPM)
| | - Michael Niederwanger
- Department of Ecophysiology, Division of Zoology, University of Innsbruck, Innsbruck, Tirol, Austria
| | - Renate Kopp
- Department of Ecophysiology, Division of Zoology, University of Innsbruck, Innsbruck, Tirol, Austria
| | - Raimund Schnegg
- Department of Ecophysiology, Division of Zoology, University of Innsbruck, Innsbruck, Tirol, Austria
| | - Reinhard Dallinger
- Department of Ecophysiology, Division of Zoology, University of Innsbruck, Innsbruck, Tirol, Austria
- * E-mail: (RD); (VPM)
| |
Collapse
|
20
|
Vázquez DP, Gianoli E, Morris WF, Bozinovic F. Ecological and evolutionary impacts of changing climatic variability. Biol Rev Camb Philos Soc 2015; 92:22-42. [PMID: 26290132 DOI: 10.1111/brv.12216] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/26/2015] [Accepted: 07/23/2015] [Indexed: 11/27/2022]
Abstract
While average temperature is likely to increase in most locations on Earth, many places will simultaneously experience higher variability in temperature, precipitation, and other climate variables. Although ecologists and evolutionary biologists widely recognize the potential impacts of changes in average climatic conditions, relatively little attention has been paid to the potential impacts of changes in climatic variability and extremes. We review the evidence on the impacts of increased climatic variability and extremes on physiological, ecological and evolutionary processes at multiple levels of biological organization, from individuals to populations and communities. Our review indicates that climatic variability can have profound influences on biological processes at multiple scales of organization. Responses to increased climatic variability and extremes are likely to be complex and cannot always be generalized, although our conceptual and methodological toolboxes allow us to make informed predictions about the likely consequences of such climatic changes. We conclude that climatic variability represents an important component of climate that deserves further attention.
Collapse
Affiliation(s)
- Diego P Vázquez
- Instituto Argentino de Investigaciones de las Zonas Áridas, CONICET, CC 507, 5500, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, M5502JMA, Mendoza, Argentina
| | - Ernesto Gianoli
- Departamento de Biología, Universidad de La Serena, Casilla 554, La Serena, 1700000, Chile.,Departamento de Botánica, Universidad de Concepción, Casilla 160-C, Concepción, 4070386, Chile
| | - William F Morris
- Biology Department, Duke University, Durham, NC, 27708-0325, U.S.A
| | - Francisco Bozinovic
- Departamento de Ecología, Center of Applied Ecology & Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, 6513677, Chile
| |
Collapse
|
21
|
Nica DV, Filimon MN, Bordean DM, Harmanescu M, Draghici GA, Dragan S, Gergen II. Impact of soil cadmium on land snails: a two-stage exposure approach under semi-field conditions using bioaccumulative and conchological end-points of exposure. PLoS One 2015; 10:e0116397. [PMID: 25790135 PMCID: PMC4366064 DOI: 10.1371/journal.pone.0116397] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022] Open
Abstract
Land snails are highly tolerant to cadmium exposure and are able to accumulate soil cadmium independently of food ingestion. However, little information exists on the kinetics of cadmium retention in terrestrial gastropods exposed to an increase in the soil cadmium content, over time. There is also little knowledge about how exposure to cadmium-polluted soils influences shell growth and architecture. In this context, we examined cadmium accumulation in the hepatopancreas and shell of juvenile Cantareus aspersus exposed to elevating high levels of cadmium in soil. Also, the toxicity of cadmium to snails was assessed using a range of conchological endpoints, including shell height, width, volume, allometry and integrity. Test snails, aged three months, were reared under semi-field conditions, fed an uncontaminated diet and exposed first, for a period of 30 days, to a series of soil cadmium concentrations, and then, for a second period of 30 days, to soils with higher cadmium content. Cadmium showed a dose-dependent accumulation in both the hepatopancreas and shell. The kinetics of cadmium retention in the hepatopancreas of snails previously exposed to cadmium-spiked soils was significantly influenced by a new exposure event. The shell was not a relevant bioaccumulator for soil cadmium. Under the present experimental conditions, only high cadmium exposure significantly affected either the shell growth or snail survival. There was no consistent effect on shell allometry, but the shell integrity, especially in rapidly growing parts, appeared to be affected by high cadmium exposure. Our results attest to the value of hepatopancreas for describing cadmium retention in land snails and to the difficulty of using conchological parameters in field surveys for estimating the environmental hazard of soil cadmium.
Collapse
Affiliation(s)
- Dragos V. Nica
- Faculty of Animal Sciences and Biotechnologies, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timisoara, Timisoara, Timis, Romania
| | | | - Despina-Maria Bordean
- Faculty of Food Processing Technology, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timisoara, Timisoara, Timis, Romania
| | - Monica Harmanescu
- Faculty of Agriculture, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timisoara, Timisoara, Timis, Romania
| | - George Andrei Draghici
- Faculty of Food Processing Technology, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timisoara, Timisoara, Timis, Romania
| | - Simona Dragan
- Department of Cardiology, “Victor Babes” University of Medicine and Pharmacy, Timisoara, Timis, Romania
| | - Iosif I. Gergen
- Faculty of Food Processing Technology, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timisoara, Timisoara, Timis, Romania
| |
Collapse
|
22
|
Baurand PE, Pedrini-Martha V, de Vaufleury A, Niederwanger M, Capelli N, Scheifler R, Dallinger R. Differential expression of metallothionein isoforms in terrestrial snail embryos reflects early life stage adaptation to metal stress. PLoS One 2015; 10:e0116004. [PMID: 25706953 PMCID: PMC4338057 DOI: 10.1371/journal.pone.0116004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 12/03/2014] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to analyze the expression of three metallothionein (MT) isoform genes (CdMT, CuMT and Cd/CuMT), already known from adults, in the Early Life Stage (ELS) of Cantareus aspersus. This was accomplished by detection of the MT isoform-specific transcription adopting Polymerase Chain Reaction (PCR) amplification and quantitative Real Time (qRT)-PCR of the three MT genes. Freshly laid eggs were kept for 24 hours under control conditions or exposed to three cadmium (Cd) solutions of increasing concentration (5, 10, and 15 mg Cd/L). The transcription of the three MT isoform genes was detected via PCR in 1, 6 and 12-day-old control or Cd-exposed embryos. Moreover, the transcription of this isoform genes during development was followed by qRT-PCR in 6 and 12-day-old embryos. Our results showed that the CdMT and Cd/CuMT genes, but not the CuMT gene, are expressed in embryos at the first day of development. The transcription of the 3 MT genes in control embryos increased with development time, suggesting that the capacities of metal regulation and detoxification may have gradually increased throughout embryogenesis. However in control embryos, the most highly expressed MT gene was that of the Cd/CuMT isoform, whose transcription levels greatly exceeded those of the other two MT genes. This contrasts with the minor significance of this gene in adult snails and suggests that in embryos, this isoform may play a comparatively more important role in metal physiology compared to adult individuals. This function in adult snails appears not to be related to Cd detoxification. Instead, snail embryos responded to Cd exposure by over-expression of the CdMT gene in a concentration-dependent manner, whereas the expression of the Cd/CuMT gene remained unaffected. Moreover, our study demonstrates the ability of snail embryos to respond very early to Cd exposure by up-regulation of the CdMT gene.
Collapse
Affiliation(s)
- Pierre-Emmanuel Baurand
- Chrono-Environnement, UMR 6249 University of Franche-Comté, 16 route de Gray, 25030, Besançon cedex, France
| | - Veronika Pedrini-Martha
- Institute of Zoology, University of Innsbruck, Technikerstraße 25, A-6020, Innsbruck, Austria
| | - Annette de Vaufleury
- Chrono-Environnement, UMR 6249 University of Franche-Comté, 16 route de Gray, 25030, Besançon cedex, France
- Department of Health Safety Environment, avenue des Rives du Lac, BP179, 70003, Vesoul cedex, France
- * E-mail:
| | - Michael Niederwanger
- Institute of Zoology, University of Innsbruck, Technikerstraße 25, A-6020, Innsbruck, Austria
| | - Nicolas Capelli
- Chrono-Environnement, UMR 6249 University of Franche-Comté, 16 route de Gray, 25030, Besançon cedex, France
| | - Renaud Scheifler
- Chrono-Environnement, UMR 6249 University of Franche-Comté, 16 route de Gray, 25030, Besançon cedex, France
| | - Reinhard Dallinger
- Institute of Zoology, University of Innsbruck, Technikerstraße 25, A-6020, Innsbruck, Austria
| |
Collapse
|
23
|
Plautz SC, Funkhouser MA, Salice CJ. New insights into parental effects and toxicity: mate availability and diet in the parental environment affect offspring responses to contaminants. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 180:41-47. [PMID: 23727566 DOI: 10.1016/j.envpol.2013.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/22/2013] [Accepted: 05/01/2013] [Indexed: 06/02/2023]
Abstract
Parental effects manifest as alterations in offspring phenotype resulting from the parental phenotype and/or parental environment. We evaluated the effects of parental diet quality and mating strategy on the toxicant tolerance of offspring in Biomphalaria glabrata snails. We raised snails either individually (self-fertilizing) or in groups of three (outcrossing) on a diet of uncooked lettuce, fish food, cooked lettuce, or cooked lettuce plus fish food. We then exposed their offspring to cadmium and malathion challenges. Cadmium tolerance varied with parental diet and was greater in the offspring of outcrossing snails than self-fertilizing snails. Malathion tolerance was not affected by parental diet but was greater in the offspring of outcrossing snails. These results indicate that offspring responses to stressors are heavily influenced by parental experience, but may depend on the specific stressor and the mechanism of action and/or detoxification.
Collapse
Affiliation(s)
- Stephanie C Plautz
- The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Box 41163, Lubbock, TX 79409, USA.
| | | | | |
Collapse
|
24
|
Moschovaki-Filippidou F, Itziou A, Dimitriadis V. Effect of starvation and hibernation on the values of five biomarkers of general and specific stress using the land snail Eobania vermiculata. Comp Biochem Physiol B Biochem Mol Biol 2013; 165:236-42. [DOI: 10.1016/j.cbpb.2013.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 05/14/2013] [Accepted: 05/14/2013] [Indexed: 11/16/2022]
|
25
|
Dallinger R, Höckner M. Evolutionary concepts in ecotoxicology: tracing the genetic background of differential cadmium sensitivities in invertebrate lineages. ECOTOXICOLOGY (LONDON, ENGLAND) 2013; 22:767-778. [PMID: 23576190 DOI: 10.1007/s10646-013-1071-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
In many toxicological and ecotoxicological studies and experimental setups, the investigator is mainly interested in traditional parameters such as toxicity data and effects of toxicants on molecular, cellular or physiological functions of individuals, species or statistical populations. It is clear, however, that such approaches focus on the phenotype level of animal species, whilst the genetic and evolutionary background of reactions to environmental toxicants may remain untold. In ecotoxicological risk assessment, moreover, species sensitivities towards pollutants are often regarded as random variables in a statistical approach. Beyond statistics, however, toxicant sensitivity of every species assumes a biological significance, especially if we consider that sensitivity traits have developed in lineages of species with common evolutionary roots. In this article, the genetic and evolutionary background of differential Cd sensitivities among invertebrate populations and species and their potential of adaptation to environmental Cd exposure will be highlighted. Important evolutionary and population genetic concepts such as genome structure and their importance for evolutionary adaptation, population structure of affected individuals, as well as micro and macroevolutionary mechanisms of Cd resistance in invertebrate lineages will be stressed by discussing examples of work from our own laboratory along with a review of relevant literature data and a brief discussion of open questions along with some perspectives for further research. Both, differences and similarities in Cd sensitivity traits of related invertebrate species can only be understood if we consider the underlying evolutionary processes and genetic (or epigenetic) mechanisms. Keeping in mind this perception can help us to better understand and interpret more precisely why the sensitivity of some species or species groups towards a certain toxicant (or metal) may be ranked in the lower or higher range of species sensitivity distributions. Hence, such a perspective will transcend a purely statistical view of the sensitivity distributions concept, and will enhance ecotoxicology in many respects.
Collapse
Affiliation(s)
- Reinhard Dallinger
- Institut für Zoologie und Limnologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
| | | |
Collapse
|
26
|
Plautz SC, Guest T, Funkhouser MA, Salice CJ. Transgenerational cross-tolerance to stress: parental exposure to predators increases offspring contaminant tolerance. ECOTOXICOLOGY (LONDON, ENGLAND) 2013; 22:854-861. [PMID: 23483328 DOI: 10.1007/s10646-013-1056-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/28/2013] [Indexed: 06/01/2023]
Abstract
Transgenerational effects of stressors can have important implications for offspring fitness and the responses of offspring to future stressful conditions. Parental effects, a common type of transgenerational effect, are non-genetic influences on offspring phenotype that result from parental phenotypes or environments. Little is known, however, about how parental exposure to a stressor effects offspring responses to other stressors despite this type of multi-stressor scenario being common. To better understand the role that parental effects have on offspring contaminant tolerance, we raised freshwater snails, Biomphalaria glabrata, in the presence or absence of predator threat (crayfish + crushed snail) for 12 weeks. Predators are common stressors in aquatic systems and can co-occur with chemical contaminants. We then collected egg masses from parental snails and exposed their offspring to cadmium and malathion survival challenges. Snails raised in the presence of predator threat displayed indicators of stress, including increased time to first reproduction, lower production of egg masses per snail per day and fewer eggs per egg mass, and had smaller shell lengths at 6.5 weeks old compared to snails not exposed to predator threat. Parental exposure to predator threat increased the cadmium tolerance of offspring but did not affect malathion tolerance. These results may have important implications for understanding effects of multiple stressors and indicate that the parental environment can influence responses to contaminants in offspring. To our knowledge, this is the first study to demonstrate that a biotic stressor in the parental environment can significantly affect the contaminant tolerance of their offspring.
Collapse
Affiliation(s)
- Stephanie C Plautz
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409, USA.
| | | | | | | |
Collapse
|
27
|
Asselman J, Glaholt SP, Smith Z, Smagghe G, Janssen CR, Colbourne JK, Shaw JR, De Schamphelaere KAC. Functional characterization of four metallothionein genes in Daphnia pulex exposed to environmental stressors. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 110-111:54-65. [PMID: 22266576 PMCID: PMC3967237 DOI: 10.1016/j.aquatox.2011.12.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 12/11/2011] [Accepted: 12/13/2011] [Indexed: 05/11/2023]
Abstract
We characterized the metallothionein genes (Mt1, Mt2, Mt3, and Mt4) in Daphnia pulex on both molecular and ecotoxicological level. We therefore conducted a bioinformatical analysis of the gene location and predicted protein sequence, and screened the upstream flanking region for regulatory elements. The number of these elements and their positions relative to the start codon varied strongly among the four genes and even among two gene duplicates (Mt1A and Mt1B), suggesting different roles of the four proteins in the organisms' response to stress. We subsequently conducted a chronic 16-day exposure of D. pulex to different environmental stressors (at sublethal levels causing approximately 50% reduction in reproduction). Based on prior knowledge, we exposed them to the metals Cd, Cu, and Ni, the moulting hormone hydroxyecdysone (20E), and the oxidative stressors cyanobacteria (Microcystis aeruginosa), and paraquat (Pq). We then compared mRNA expression levels of the four Mt genes under these stress conditions with control conditions in "The Chosen One" clone (TCO), for which the full genome was sequenced and annotated. All together, the mRNA expression results under the different stress regimes indicate that different Mt genes may play different and various roles in the response of D. pulex to stress and that some (but not all) of the differences among the four genes could be related to the pattern of regulatory elements in their upstream flanking region.
Collapse
Affiliation(s)
- J Asselman
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Belgium.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
The metal binding abilities of Megathura crenulata metallothionein (McMT) in the frame of gastropoda MTs. J Inorg Biochem 2011; 108:84-90. [PMID: 22209022 DOI: 10.1016/j.jinorgbio.2011.11.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 11/13/2011] [Accepted: 11/14/2011] [Indexed: 11/21/2022]
Abstract
Metallothioneins (MTs) are proteins that play a major role in metal homeostasis and/or detoxification in all kind of organisms. The MT gene/protein system of gastropod molluscs provides an invaluable model to study the diversification mechanisms that have enabled MTs to achieve metal-binding specificity through evolution. Most pulmonate gastropods, particularly terrestrial snails, harbor three paralogous isogenes encoding three MT isoforms with different metal binding preferences: the highly specific CdMT and CuMT isoforms, for cadmium and copper respectively, and the unspecific Cd/CuMT isoform. Megathura crenulata is a non-pulmonate gastropod in which only one MT isogene has so far been reported. In order to elucidate the metal binding character of the corresponding peptide (McMT), it has been recombinantly synthesized in the presence of Cd(2+), Zn(2+) or Cu(2+), and the corresponding metal complexes have been analyzed using electrospray mass spectrometry, and CD and UV-visible spectroscopy. The metal-binding traits exhibited by McMT revealed that it is an unspecific MT, similarly to the pulmonate Cd/CuMT isoforms. This is in full concordance with the protein sequence distance analysis in relation to other gastropod MTs.
Collapse
|
29
|
Höckner M, Dallinger R, Stürzenbaum SR. Nematode and snail metallothioneins. J Biol Inorg Chem 2011; 16:1057-65. [PMID: 21822727 DOI: 10.1007/s00775-011-0826-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 07/25/2011] [Indexed: 01/27/2023]
Abstract
Metallobiologists have, at large, neglected soil dwelling invertebrates; exceptions are the nematode (Caenorhabditis elegans) and snails (Helix pomatia and Cantareus aspersus). This review aims to compare and contrast the molecular, protein and cellular mechanisms of the multifunctional nematode and snail metallothioneins (MTs). The C. elegans genome contains two MT genes, mtl-1, which is constitutively expressed in the pharynx and likely to act as an essential and/or toxic metal sensor, and mtl-2, which plays a negligible role under normal physiological conditions but is strongly induced (as mtl-1) in intestinal cells upon metal exposure. It has been possible to follow the intricate phenotypic responses upon the knockdown/knockout of single and multiple MT isoforms and we have started to decipher the multifunctional role of C. elegans MTs. The snails have contributed to our understanding regarding MT evolution and diversity, structure and metal-specific functionality. The H. pomatia and C. aspersus genomes contain at least three MT isoform genes. CdMT is responsible for cadmium detoxification, CuMT is involved in copper homeostasis and Cd/CuMT is a putative ancestral MT possibly only of minor importance in metal metabolism. Further investigations of nematode, snail and other invertebrate MTs will allow the development of alternative biomarker approaches and lead to an improved understanding of metallobiology, protein evolution and toxicogenomics.
Collapse
Affiliation(s)
- Martina Höckner
- Institute of Zoology, University of Innsbruck, 6020, Innsbruck, Austria
| | | | | |
Collapse
|
30
|
Physiological relevance and contribution to metal balance of specific and non-specific Metallothionein isoforms in the garden snail, Cantareus aspersus. Biometals 2011; 24:1079-92. [PMID: 21625890 DOI: 10.1007/s10534-011-9466-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
Abstract
Variable environmental availability of metal ions represents a constant challenge for most organisms, so that during evolution, they have optimised physiological and molecular mechanisms to cope with this particular requirement. Metallothioneins (MTs) are proteins that play a major role in metal homeostasis and as a reservoir. The MT gene/protein systems of terrestrial helicid snails are an invaluable model for the study of metal-binding features and MT isoform-specific functionality of these proteins. In the present study, we characterised three paralogous MT isogenes and their expressed products in the escargot (Cantareus aspersus). The metal-dependent transcriptional activation of the three isogenes was assessed using quantitative Real Time PCR. The metal-binding capacities of the three isoforms were studied by characterising the purified native complexes. All the data were analysed in relation to the trace element status of the animals after metal feeding. Two of the three C. aspersus MT (CaMT) isoforms appeared to be metal-specific, (CaCdMT and CaCuMT, for cadmium and copper respectively). A third isoform (CaCd/CuMT) was non-specific, since it was natively recovered as a mixed Cd/Cu complex. A specific role in Cd detoxification for CaCdMT was revealed, with a 80-90% contribution to the Cd balance in snails exposed to this metal. Conclusive data were also obtained for the CaCuMT isoform, which is involved in Cu homeostasis, sharing about 30-50% of the Cu balance of C. aspersus. No apparent metal-related physiological function was found for the third isoform (CaCd/CuMT), so its contribution to the metal balance of the escargot may be, if at all, of only marginal significance, but may enclose a major interest in evolutionary studies.
Collapse
|
31
|
Palacios O, Pagani A, Pérez-Rafael S, Egg M, Höckner M, Brandstätter A, Capdevila M, Atrian S, Dallinger R. Shaping mechanisms of metal specificity in a family of metazoan metallothioneins: evolutionary differentiation of mollusc metallothioneins. BMC Biol 2011; 9:4. [PMID: 21255385 PMCID: PMC3033865 DOI: 10.1186/1741-7007-9-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 01/21/2011] [Indexed: 01/29/2023] Open
Abstract
Background The degree of metal binding specificity in metalloproteins such as metallothioneins (MTs) can be crucial for their functional accuracy. Unlike most other animal species, pulmonate molluscs possess homometallic MT isoforms loaded with Cu+ or Cd2+. They have, so far, been obtained as native metal-MT complexes from snail tissues, where they are involved in the metabolism of the metal ion species bound to the respective isoform. However, it has not as yet been discerned if their specific metal occupation is the result of a rigid control of metal availability, or isoform expression programming in the hosting tissues or of structural differences of the respective peptides determining the coordinative options for the different metal ions. In this study, the Roman snail (Helix pomatia) Cu-loaded and Cd-loaded isoforms (HpCuMT and HpCdMT) were used as model molecules in order to elucidate the biochemical and evolutionary mechanisms permitting pulmonate MTs to achieve specificity for their cognate metal ion. Results HpCuMT and HpCdMT were recombinantly synthesized in the presence of Cd2+, Zn2+ or Cu2+ and corresponding metal complexes analysed by electrospray mass spectrometry and circular dichroism (CD) and ultra violet-visible (UV-Vis) spectrophotometry. Both MT isoforms were only able to form unique, homometallic and stable complexes (Cd6-HpCdMT and Cu12-HpCuMT) with their cognate metal ions. Yeast complementation assays demonstrated that the two isoforms assumed metal-specific functions, in agreement with their binding preferences, in heterologous eukaryotic environments. In the snail organism, the functional metal specificity of HpCdMT and HpCuMT was contributed by metal-specific transcription programming and cell-specific expression. Sequence elucidation and phylogenetic analysis of MT isoforms from a number of snail species revealed that they possess an unspecific and two metal-specific MT isoforms, whose metal specificity was achieved exclusively by evolutionary modulation of non-cysteine amino acid positions. Conclusion The Roman snail HpCdMT and HpCuMT isoforms can thus be regarded as prototypes of isoform families that evolved genuine metal-specificity within pulmonate molluscs. Diversification into these isoforms may have been initiated by gene duplication, followed by speciation and selection towards opposite needs for protecting copper-dominated metabolic pathways from nonessential cadmium. The mechanisms enabling these proteins to be metal-specific could also be relevant for other metalloproteins.
Collapse
Affiliation(s)
- Oscar Palacios
- Departamento Química, Faculty Ciències, Universitat Autònoma de Barcelona, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Cadmium stress stimulates tissue turnover in Helix pomatia: increasing cell proliferation from metal tolerance to exhaustion in molluscan midgut gland. Cell Tissue Res 2010; 341:159-71. [PMID: 20480182 DOI: 10.1007/s00441-010-0980-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Accepted: 04/07/2010] [Indexed: 10/19/2022]
Abstract
In terrestrial pulmonate snails, cadmium (Cd) uptake leads to the induction of a Cd-specific metallothionein isoform (Cd-MT) that protects against adverse interactions of this toxic metal ion. Increasing concentrations of Cd cause increased individual mortality possibly linked to pathological alterations in the snail midgut gland. Histological, immuno-histochemical, and electron-microscopic methods in combination with tissue metal analyses and quantification of MT induction parameters were applied to the midgut gland of Cd-exposed Roman snails (Helix pomatia). Conspicuous concentration-dependent alterations occurred in this organ, including the metal-induced increase of Cd-MT concentration and manifestation of Cd-MT mRNA precipitations in all midgut gland cell types. The most evident alteration was an increase of cellular turnover reflected by enhanced cell proliferation. Intensified vesiculation of endoplasmic reticulum was noted in basophilic cells and an increasing formation of lipofuscin granules in excretory cells. At the highest Cd concentrations, mitochondrial membranes were disrupted in basophilic cells, and lipofuscin granules were released from excretory cells into the midgut gland tubular system. Some of these alterations (e.g., increased cell proliferation rate, vesiculation of endoplasmic reticulum) detected at low Cd concentrations were interpreted as adaptive response processes enhancing the tolerance of exposed individuals to metal stress. Cellular alterations at higher Cd concentrations (e.g., mitochondrial structural damage) clearly represented ongoing irreversible cellular disruption. Combined evaluation of cellular biomarkers and MT saturation levels indicated that the transition from stress resistance to depletion of resistance capacity occurred above a threshold of 0.8 micromol Cd/g dry weight in the midgut gland of H. pomatia. At these Cd concentrations, Cd-MT was saturated with Cd(2+) ions, whereas at the cellular level, structural alterations turned into pathological deterioration.
Collapse
|
33
|
Höckner M, Stefanon K, Schuler D, Fantur R, de Vaufleury A, Dallinger R. Coping with cadmium exposure in various ways: the two helicid snails Helix pomatia and Cantareus aspersus share the metal transcription factor-2, but differ in promoter organization and transcription of their Cd-metallothionein genes. ACTA ACUST UNITED AC 2010; 311:776-87. [PMID: 19691054 DOI: 10.1002/jez.564] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Gastropods are able to withstand fluctuating availabilities of nonessential trace elements such as cadmium by induction of Cd-specific metallothionein isoform (Cd-MT) expression. As in other species, the induction mechanism involves the binding of metal-regulatory transcription factors (MTF-1 or MTF-2) to metal responsive elements (MREs) in the MT promoter regions. Cd-dependent transcription of Cd-MT genes was assessed by quantitative real time PCR in two helicid gastropods, Helix pomatia and Cantareus aspersus, over a period of eight days. The promoter regions of the Cd-MT genes of the two species were sequenced and compared regarding the position of MREs and other relevant potential transcription factor binding sites (TFBs). Cd-MT gene transcription is induced after Cd exposure in Helix pomatia and Cantareus aspersus, showing a transient peak in Helix pomatia, contrasting with a persistent induction rate in Cantareus aspersus. Since the existence of MTF-2 was verified in both species, differing transcription patterns of Cd-MT genes must be due to functional differences in their metal-responsive promoter regions. Both promoters contain a proximal cluster of three MREs overlapping with TFBs for the transcriptional regulator Sp1. In contrast to Cantareus aspersus, however, the Cd-MT gene of Helix pomatia hosts an additional distal MRE overlapping with a Sp1 binding site and a CACCC box. Inhibitory effects of MRE overlapping Sp1 binding sites were observed in other MT genes. We therefore suggest that transient Cd-MT transcription upon Cd(2+) exposure in Helix pomatia may be the result of an inhibitory action of the distal MRE cluster.
Collapse
Affiliation(s)
- M Höckner
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
| | | | | | | | | | | |
Collapse
|