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Teng Y, Yang Y, Wang Z, Guan W, Liu Y, Yu H, Zou L. The cadmium tolerance enhancement through regulating glutathione conferred by vacuolar compartmentalization in Aspergillus sydowii. CHEMOSPHERE 2024; 352:141500. [PMID: 38373444 DOI: 10.1016/j.chemosphere.2024.141500] [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: 07/22/2023] [Revised: 12/20/2023] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
Aspergillus was found to be a vital hyperaccumulation species for heavy metal removal with admirable tolerance capacity. But the potential tolerance mechanism has not been completely studied. This study quantified the amounts of total cadmium (Cd), Cd2+, glutathione (GSH), and reactive oxygen species (ROS) in the protoplasts and vacuoles of mycelium. We modulated GSH synthesis using buthionine sulfoximine (BSO) and 2-oxothiazolidine-4-carboxylic acid (OTC) to investigate the subcellular regulatory mechanisms of GSH in the accumulation of Cd. The results confirmed that GSH plays a crucial role in vacuolar compartmentalization under Cd stress. GSH and GSSG as a redox buffer to keep the cellular redox state in balance and GSH as a metal chelating agent to reduce toxicity. When regulating the decreased GSH content with BSO, and increased GSH content with OTC, the system of Cd-GSH-ROS can change accordingly, this also supported that vacuolar compartmentalization is a detoxification strategy that can modulate the transport and storage of substances inside and outside the vacuole reasonably. Interestingly, GSH tended to be distributed in the cytoplasm, the battleground of redox takes place in the cytoplasm but not in the vacuole. These finding potentially has implications for the understanding of tolerance behavior and detoxification mechanisms of cells. In the future bioremediation of Cd in soil, the efficiency of soil remediation can be improved by developing organisms with high GSH production capacity.
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Affiliation(s)
- Yue Teng
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215009, China.
| | - Yan Yang
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhenjun Wang
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Wenjie Guan
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yutong Liu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Hongyan Yu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Luyi Zou
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
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Gutiérrez-Escobedo G, Orta-Zavalza E, Castaño I, De Las Peñas A. Role of glutathione in the oxidative stress response in the fungal pathogen Candida glabrata. Curr Genet 2013; 59:91-106. [PMID: 23455613 DOI: 10.1007/s00294-013-0390-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/07/2013] [Accepted: 02/12/2013] [Indexed: 10/27/2022]
Abstract
Candida glabrata, an opportunistic fungal pathogen, accounts for 18-26 % of all Candida systemic infections in the US. C. glabrata has a robust oxidative stress response (OSR) and in this work we characterized the role of glutathione (GSH), an essential tripeptide-like thiol-containing molecule required to keep the redox homeostasis and in the detoxification of metal ions. GSH is synthesized from glutamate, cysteine, and glycine by the sequential action of Gsh1 (γ-glutamyl-cysteine synthetase) and Gsh2 (glutathione synthetase) enzymes. We first screened for suppressor mutations that would allow growth in the absence of GSH1 (gsh1∆ background) and found a single point mutation in PRO2 (pro2-4), a gene that encodes a γ-glutamyl phosphate reductase and catalyzes the second step in the biosynthesis of proline. We demonstrate that GSH is important in the OSR since the gsh1∆ pro2-4 and gsh2∆ mutant strains are more sensitive to oxidative stress generated by H2O2 and menadione. GSH is also required for Cadmium tolerance. In the absence of Gsh1 and Gsh2, cells show decreased viability in stationary phase. Furthermore, C. glabrata does not contain Saccharomyces cerevisiae high affinity GSH transporter ortholog, ScOpt1/Hgt1, however, our genetic and biochemical experiments show that the gsh1∆ pro2-4 and gsh2∆ mutant strains are able to incorporate GSH from the medium. Finally, GSH and thioredoxin, which is a second redox system in the cell, are not essential for the catalase-independent adaptation response to H2O2.
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Affiliation(s)
- Guadalupe Gutiérrez-Escobedo
- IPICYT, Camino a la Presa San José 2055, División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica, 78216, San Luis Potosí, San Luis Potosí, México
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Dworeck T, Zimmermann M. Site directed mutagenesis of Schizosaccharomyces pombe glutathione synthetase produces an enzyme with homoglutathione synthetase activity. PLoS One 2012; 7:e46580. [PMID: 23091597 PMCID: PMC3473041 DOI: 10.1371/journal.pone.0046580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 08/31/2012] [Indexed: 11/30/2022] Open
Abstract
Three different His-tagged, mutant forms of the fission yeast glutathione synthetase (GSH2) were derived by site-directed mutagenesis. The mutant and wild-type enzymes were expressed in E. coli DH5α and affinity purified in a two-step procedure. Analysis of enzyme activity showed that it was possible to shift the substrate specificity of GSH2 from Gly (km 0,19; wild-type) to β-Ala or Ser. One mutation (substitution of Ile471, Cy472 to Met and Val and Ala 485 and Thr486 to Leu and Pro) increased the affinity of GSH2 for β-Ala (km 0,07) and lowered the affinity for Gly (km 0,83), which is a characteristic of the enzyme homoglutathione synthetase found in plants. Substitution of Ala485 and Thr486 to Leu and Pro only, increased instead the affinity of GSH2 for Ser (km 0,23) as a substrate, while affinity to Gly was preserved (km 0,12). This provides a new biosynthetic pathway for hydroxymethyl glutathione, which is known to be synthesized from glutathione and Ser in a reaction catalysed by carboxypeptidase Y. The reported findings provide further insight into how specific amino acids positioned in the GSH2 active site facilitate the recognition of different amino acid substrates, furthermore they support the evolutionary theory that homoglutathione synthetase evolved from glutathione synthetase by a single gene duplication event.
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Affiliation(s)
- Tamara Dworeck
- Department of Biology, RWTH Aachen University, Aachen, Germany
| | - Martin Zimmermann
- Institute of Biologie IV- Applied Microbiology, RWTH Aachen University, Aachen, Germany
- * E-mail:
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Xu H, Song P, Gu W, Yang Z. Effects of heavy metals on production of thiol compounds and antioxidant enzymes in Agaricus bisporus. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2011; 74:1685-92. [PMID: 21529942 DOI: 10.1016/j.ecoenv.2011.04.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 12/12/2010] [Accepted: 04/03/2011] [Indexed: 05/13/2023]
Abstract
In a pre-experiment, Agaricus bisporus mycelia grown in PDL medium were found to have a substantial ability to tolerate and accumulate heavy metals. In the study, we investigated changes in the contents of soluble protein and thiol compounds as well as the activities of antioxidant enzymes caused by copper, zinc, lead, and cadmium (nitrate salts) in mycelia of A. bisporus during short-and long-term exposure. Results showed that high-level metal concentrations significantly decrease the contents of soluble protein after long-term exposure, Cu and Zn concentrations significantly increase the thiol compounds levels after long-term exposure, while high-level Cd significantly decrease thiol compounds after long-term exposure. Additionally, SOD activities were significantly increased after long-term exposure to metals, especially to Cd. The CAT activities were enhanced after long-term exposure to low-level Cu and high-level Zn, and enhanced after short-and long-term exposure to high-level Pb. The POD activities were significantly increased after long-term exposure to metals, and increased after short-term exposure to Cd and high-level Pb.
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Affiliation(s)
- Heng Xu
- Key Laboratory for Bio-resources and Eco-environment of Education Ministry, College of Life Science, Sichuan University, Chengdu 610064, China
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Gorfer M, Persak H, Berger H, Brynda S, Bandian D, Strauss J. Identification of heavy metal regulated genes from the root associated ascomycete Cadophora finlandica using a genomic microarray. ACTA ACUST UNITED AC 2009; 113:1377-88. [PMID: 19770041 DOI: 10.1016/j.mycres.2009.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 09/04/2009] [Accepted: 09/15/2009] [Indexed: 10/20/2022]
Abstract
The ascomycete Cadophora finlandica, which can form mycorrhizas with ectomycorrhizal and ericoid hosts, is commonly found in heavy metal polluted soils. To understand the selective advantage of this organism at contaminated sites heavy metal regulated genes from C. finlandica were investigated. For gene identification a strategy based on a genomic microarray was chosen, which allows a rapid, genome-wide screening in genetically poorly characterized organisms. In a preliminary screen eleven plasmids covering eight distinct genomic regions and encoding a total of ten Cd-regulated genes were identified. Northern analyses with RNA from C. finlandica grown in the presence of either Cd, Pb or Zn revealed different transcription patterns in response to the heavy metals present in the growth medium. The Cd-regulated genes are predicted to encode several extracellular proteins with unknown functions, transporters, a centaurin-type regulator of intracellular membrane trafficking, a GNAT-family acetyltransferase and a B-type cyclin.
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Affiliation(s)
- Markus Gorfer
- Department of Applied Genetics and Cell Biology, Fungal Genomics Unit, Austrian Research Centers and BOKU-University Vienna, Muthgasse 18, 1190 Vienna, Austria.
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Guimarães-Soares L, Pascoal C, Cássio F. Effects of heavy metals on the production of thiol compounds by the aquatic fungi Fontanospora fusiramosa and Flagellospora curta. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2007; 66:36-43. [PMID: 16321439 DOI: 10.1016/j.ecoenv.2005.10.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 08/26/2005] [Accepted: 10/11/2005] [Indexed: 05/05/2023]
Abstract
The aquatic hyphomycetes Fontanospora fusiramosa and Flagellospora curta isolated from a clean and a metal-contaminated site, respectively, were tested for the production of thiol compounds when exposed to Cd, Zn, and Cu for short- and long-term periods. After 8 days, control cultures of F. curta had a total thiol (T-SH) concentration in mycelia of 3.46 +/- 0.37 micromol g(-1) dry mass, which was 2.4 times greater than that of F. fusiramosa. In both species, nonprotein (NP-SH) and protein-bound (PB-SH) thiols accounted for 30% and 70% of T-SH, respectively. F. curta increased the production of thiol compounds, namely NP-SH, more rapidly than F. fusiramosa when exposed to Cd or Zn. The greater increases in either NP-SH or PB-SH occurred in F. fusiramosa after long-term exposure to all metals; in this case, the increases of PB-SH overwhelmed those of NP-SH. Long-term exposure to metals also increased the mycelial protein concentration.
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Affiliation(s)
- Luís Guimarães-Soares
- Departamento de Biologia, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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Mendoza-Cózatl D, Loza-Tavera H, Hernández-Navarro A, Moreno-Sánchez R. Sulfur assimilation and glutathione metabolism under cadmium stress in yeast, protists and plants. FEMS Microbiol Rev 2005; 29:653-71. [PMID: 16102596 DOI: 10.1016/j.femsre.2004.09.004] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Revised: 08/03/2004] [Accepted: 09/17/2004] [Indexed: 11/28/2022] Open
Abstract
Glutathione (gamma-glu-cys-gly; GSH) is usually present at high concentrations in most living cells, being the major reservoir of non-protein reduced sulfur. Because of its unique redox and nucleophilic properties, GSH serves in bio-reductive reactions as an important line of defense against reactive oxygen species, xenobiotics and heavy metals. GSH is synthesized from its constituent amino acids by two ATP-dependent reactions catalyzed by gamma-glutamylcysteine synthetase and glutathione synthetase. In yeast, these enzymes are found in the cytosol, whereas in plants they are located in the cytosol and chloroplast. In protists, their location is not well established. In turn, the sulfur assimilation pathway, which leads to cysteine biosynthesis, involves high and low affinity sulfate transporters, and the enzymes ATP sulfurylase, APS kinase, PAPS reductase or APS reductase, sulfite reductase, serine acetyl transferase, O-acetylserine/O-acetylhomoserine sulfhydrylase and, in some organisms, also cystathionine beta-synthase and cystathionine gamma-lyase. The biochemical and genetic regulation of these pathways is affected by oxidative stress, sulfur deficiency and heavy metal exposure. Cells cope with heavy metal stress using different mechanisms, such as complexation and compartmentation. One of these mechanisms in some yeast, plants and protists is the enhanced synthesis of the heavy metal-chelating molecules GSH and phytochelatins, which are formed from GSH by phytochelatin synthase (PCS) in a heavy metal-dependent reaction; Cd(2+) is the most potent activator of PCS. In this work, we review the biochemical and genetic mechanisms involved in the regulation of sulfate assimilation-reduction and GSH metabolism when yeast, plants and protists are challenged by Cd(2+).
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Affiliation(s)
- David Mendoza-Cózatl
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Juan Badiano 1, Col. Sección XVI Tlalpan, México.
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Rea PA, Vatamaniuk OK, Rigden DJ. Weeds, worms, and more. Papain's long-lost cousin, phytochelatin synthase. PLANT PHYSIOLOGY 2004; 136:2463-74. [PMID: 15375203 PMCID: PMC523314 DOI: 10.1104/pp.104.048579] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 07/15/2004] [Accepted: 07/18/2004] [Indexed: 05/18/2023]
Affiliation(s)
- Philip A Rea
- Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Bae W, Chen X. Proteomic Study for the Cellular Responses to Cd2+ in Schizosaccharomyces pombe Through Amino Acid-coded Mass Tagging and Liquid Chromatography Tandem Mass Spectrometry. Mol Cell Proteomics 2004; 3:596-607. [PMID: 15004206 DOI: 10.1074/mcp.m300122-mcp200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cadmium (Cd(2+)) is one of well-known toxic heavy metal ions. To gain a global understanding how Cd(2+) affects cells at the molecular level, we systematically studied the cellular response of the fission yeast Schizosaccharomyces pombe to Cd(2+) using our integrated proteomic strategy of amino acid-coded mass tagging (AACT) and liquid chromatography-tandem mass spectrometry. Our proteome-wide investigation unequivocally identified 1133 S. pombe proteins. Of which, the AACT-based quantitative analysis revealed 106 up-regulated and 55 down-regulated proteins on the Cd(2+) exposure. The most prevalent functional class in the up-regulated proteins, approximately 28% of our profile, was the proteins involved in protein biosynthesis, showing a time-dependent biphasic expression pattern characteristic with rapid initial induction and later repression. Most significantly, 27 proteins functionally classified as cell rescue and defense were up-regulated for oxygen and radical detoxification, heat shock response, and other stress response. Furthermore, the large precursor sequence coverage of our AACT approach allowed us to unequivocally identify and quantitate different isozymes for glutathione S-transferase, which have close similarity in their amino acid sequence. Our quantitative dataset also showed that 80% of the up-regulated proteins found in the S. pombe response were different from those in the Saccharomyces cerevisiae response. The function of some of the key identifications was validated through biochemical assays. It is very interesting that the induction of cysteine synthase expression was not observed in our study, although it has been proven as a critical enzyme to supply free cysteines for the enhancing synthesis of Cd(2+)-sequestering molecules such as glutathione and phytochelatins in plants and some yeasts. Our quantitative proteomic result instead suggested that, as an alternative mechanism for the detoxification of Cd(2+), S. pombe produced significantly higher level of inorganic sulfide to immobilize cellular Cd(2+) as a form of CdS nanocrystallites capped with glutathione and/or phytochelatins.
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Affiliation(s)
- Weon Bae
- B-2, MS M888, Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Czakó-Vér K, Koósz Z, Antal J, Rácz T, Sipiczki M, Pesti M. Characterization of chromate-sensitive and -tolerant mutants of Schizosaccharomyces pombe. Folia Microbiol (Praha) 2004; 49:31-6. [PMID: 15114862 DOI: 10.1007/bf02931642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Stable chromium(VI)-sensitive and -tolerant mutants were obtained by induced mutagenesis of Schizosaccharomyces pombe lysine and leucine auxotrophic heterothallic strains 6chr+ and 9chr+. Eleven of them were selected for further studies. Fast transport of 51CrO4(2-) was detected in a representative sensitive mutant, chr-51S, while the tolerant mutant chr1-66T and the parental strain 6chr+ exhibited significantly lower 51CrO4(2-) uptake. The segregation of tetrads of three selected CrVI-tolerant mutants, chr1-66T, chr1-14T and chr2-04T, strongly indicated that tolerance was determined by single mutations. Random spore analysis proved that the mutations of chr1-66T and chr1-14T were allelic and the mutation of mutant chr2-04T was not allelic with the mutation of chr1-66T. Recombinants carrying the ura4D18 selective marker were created for transformation experiments. Two of them (chr1-661T and chr2-046T) can be used to clone and identify the genes responsible for their CrVI tolerance phenotype.
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Affiliation(s)
- K Czakó-Vér
- Department of General and Environmental Microbiology, Faculty of Science, University of Pécs, 7601 Pécs, Hungary
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Phlippen N, Hoffmann K, Fischer R, Wolf K, Zimmermann M. The glutathione synthetase of Schizosaccharomyces pombe is synthesized as a homodimer but retains full activity when present as a heterotetramer. J Biol Chem 2003; 278:40152-61. [PMID: 12734194 DOI: 10.1074/jbc.m303102200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Glutathione synthetase was overexpressed as a histidine-tagged protein in Schizosaccharomyces pombe and purified by two-step affinity chromatography. The recovered enzyme occurred in two different forms: a homodimeric protein consisting of two identical 56-kDa subunits and a heterotetrameric protein composed of two 32-kDa and two 24-kDa subfragments. Both forms are encoded by the GSH2 gene. The 56-Da protein corresponds to the complete GSH2 open reading frame, while the subfragments are produced following the cleavage of this larger protein by a metalloprotease. A stable homodimer was obtained by site-directed mutagenesis to remove the protease cleavage site, and this showed normal activity. A structural model of the fission yeast glutathione synthetase was produced, based on the x-ray coordinates of the human enzyme. According to this model the interacting domains of the proteolytic subfragments are strongly entangled. The subfragments were therefore coexpressed as independent proteins. These subfragments assembled correctly to yield functional heterotetramers with equivalent activity to the wild type enzyme. Furthermore, a permuted version of the protein was created. This also showed normal levels of glutathione synthetase activity. These data provide novel insight into the mechanisms of protein folding and the structure and evolution of the glutathione synthetase family.
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Affiliation(s)
- Nadine Phlippen
- Institute of Biology IV (Microbiology and Genetics), Aachen University, Worringer Weg, D-52056 Aachen, Germany
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Clemens S, Simm C. Schizosaccharomyces pombe as a model for metal homeostasis in plant cells: the phytochelatin-dependent pathway is the main cadmium detoxification mechanism. THE NEW PHYTOLOGIST 2003; 159:323-330. [PMID: 33873355 DOI: 10.1046/j.1469-8137.2003.00811.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sequestration of metal ions by phytochelatins is an important metal tolerance mechanism in a wide range of organisms including plants and certain fungi. Substantial progress in understanding phytochelatin formation at the molecular level has been made in Schizosaccharomyces pombe. The genome of S. pombe has been completely sequenced and all the necessary tools of functional genomics are available. Since most other proteins implicated in plant metal tolerance and homeostasis are also present in this yeast, it represents a very powerful system to elucidate basic mechanisms of metal buffering, sequestration, and toxicity in cells that form phytochelatins. Here, we summarize the work on phytochelatin formation and metal homeostasis in S. pombe. We describe examples of molecular insights obtained from experiments with S. pombe that will be useful in guiding studies with plants. We also provide evidence for the dominance of the phytochelatin pathway in Cd detoxification in S. pombe.
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Affiliation(s)
- Stephan Clemens
- Leibniz-Institut für Pflanzenbiochemie, Weinberg 3, D-06120 Halle/Saale, Germany
| | - Claudia Simm
- Leibniz-Institut für Pflanzenbiochemie, Weinberg 3, D-06120 Halle/Saale, Germany
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Ubiyvovk VM, Nazarko TY, Stasyk OG, Sohn MJ, Kang HA, Sibirny AA. GSH2, a gene encoding γ-glutamylcysteine synthetase in the methylotrophic yeastHansenula polymorpha. FEMS Yeast Res 2002. [DOI: 10.1111/j.1567-1364.2002.tb00101.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Mendoza-Cozatl D, Devars S, Loza-Tavera H, Moreno-Sánchez R. Cadmium accumulation in the chloroplast of Euglena gracilis. PHYSIOLOGIA PLANTARUM 2002; 115:276-283. [PMID: 12060246 DOI: 10.1034/j.1399-3054.2002.1150214.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Intracellular distribution of Cd, cysteine, glutathione, and Cd-induced thiol peptides in Euglena gracilis cultured under photoheterotrophic conditions was studied. After 3 days of culture with 0.2 mM CdCl2, 62% of the Cd accumulated by cells was equally distributed between the cytosolic and chloroplastic fractions. However, after 8 days, metal content increased in the crude chloroplastic fraction to 40% of total and decreased to 19% in the cytosol; in Percoll-purified chloroplasts the estimated content of Cd raised to 62%. Accumulation of Cd in chloroplasts could be mediated by a transporter of free Cd2+, since uptake of added CdCl2 in isolated chloroplasts exhibited a hyperbolic type of kinetics with a Km of 57 &mgr;M and Vmax of 3.7 nmol (mg protein)-1 min-1. The contents of cysteine and glutathione markedly increased in both chloroplasts (7-19 times) and cytosol (4-9 times) by exposure to Cd2+, although they were always higher in the cytosol. Thiol-containing peptides induced by Cd were mainly located in the cytosol after 3 days, and in the chloroplasts after 8 days of culture. The data suggested that Cd was compartmentalized into chloroplasts in a process that may involve the transport of free Cd and the participation of thiol-peptides.
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Affiliation(s)
- David Mendoza-Cozatl
- Departamento de Bioquimica, Instituto Nacional de Cardiologia, D.F. 14080, Mexico Departamento de Bioquimica, Facultad de Quimica, UNAM, D.F. 04510, Mexico
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Avery SV. Metal toxicity in yeasts and the role of oxidative stress. ADVANCES IN APPLIED MICROBIOLOGY 2002; 49:111-42. [PMID: 11757348 DOI: 10.1016/s0065-2164(01)49011-3] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- S V Avery
- School of Life and Environmental Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Kriegmaier M, Zimmermann M, Wolf K, Zimmermann U, Sukhorukov VL. Dielectric spectroscopy of Schizosaccharomyces pombe using electrorotation and electroorientation. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1568:135-46. [PMID: 11750761 DOI: 10.1016/s0304-4165(01)00210-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two complementary AC electrokinetic techniques electrorotation (ER) and electroorientation (EO) enabled the dielectric characterization of the rod-shaped fission yeast Schizosaccharomyces pombe. The use of microstructured electrodes allowed both ER and EO measurements to be performed over wide ranges of field frequency and medium conductivity. Due to their layered structure, living S. pombe cells exhibited up to three well resolved peaks in their ER spectra and also two distinct orientations, i.e., parallel or perpendicular to the imposed linear field. Heat treatment and enzymatic protoplast isolation led to dramatic changes in the electrokinetic behavior of fission yeast. Application of the theoretical models linking the ER and EO spectra yielded the dielectric parameters of the major structural units of S. pombe cells (cell wall, plasma membrane and cytosol). The dielectric characterization of yeasts has an enormous impact in biotechnology and biomedicine, because electric field pulse techniques (electrofusion and electropermeabilization) are widely used for production of transgenic yeast strains of economic importance. The present study also showed that combined ER and EO measurements can be employed as a powerful diagnostic tool for analyzing changes in yeast structure and physiology upon exposure to various stress conditions.
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Affiliation(s)
- M Kriegmaier
- Lehrstuhl für Biotechnologie der Universität Würzburg, Biozentrum, Am Hubland, D-97074 Würzburg, Germany
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The Role of Glutathione in Plant Reaction and Adaptation to Excess Metals. PLANT ECOPHYSIOLOGY 2001. [DOI: 10.1007/0-306-47644-4_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Kotrba P, Ruml T. Bioremediation of Heavy Metal Pollution Exploiting Constituents, Metabolites and Metabolic Pathways of Livings. A Review. ACTA ACUST UNITED AC 2000. [DOI: 10.1135/cccc20001205] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Removal of heavy metals from the soil and water or their remediation from the waste streams "at source" has been a long-term challenge. During the recent era of environmental protection, the use of microorganisms for the recovery of metals from waste streams as well as employment of plants for landfill applications has generated growing attention. Many studies have demonstrated that both prokaryotes and eukaryotes have the ability to remove metals from contaminated water or waste streams. They sequester metals from soils and sediments or solubilize them to aid their extraction. The proposed microbial processes for bioremediation of toxic metals and radionuclides from waste streams employ living cells and non-living biomass or biopolymers as biosorbents. Microbial biotransformation of metals or metalloids results in an alteration of their oxidation state or in their alkylation and subsequent precipitation or volatilization. Specific metabolic pathways leading to precipitation of heavy metals as metal sulfides, phosphates or carbonates possess significance for possible biotechnology application. Moreover, the possibility of altering the properties of living species used in heavy metal remediation or constructing chimeric organisms possessing desirable features using genetic engineering is now under study in many laboratories. The encouraging evidence as to the usefulness of living organisms and their constituents as well as metabolic pathways for the remediation of metal contamination is reviewed here. A review with 243 references.
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