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Bernard E, Guéguen C. Molecular changes in phenolic compounds in Euglena gracilis cells grown under metal stress. FRONTIERS IN PLANT SCIENCE 2023; 14:1099375. [PMID: 37229138 PMCID: PMC10203486 DOI: 10.3389/fpls.2023.1099375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/21/2023] [Indexed: 05/27/2023]
Abstract
Metal presence in the aquatic ecosystem has increased and diversified over the last decades due to anthropogenic sources. These contaminants cause abiotic stress on living organisms that lead to the production of oxidizing molecules. Phenolic compounds are part of the defense mechanisms countering metal toxicity. In this study, the production of phenolic compounds by Euglena gracilis under three different metal stressors (i.e. cadmium, copper, or cobalt) at sub-lethal concentration was assessed using an untargeted metabolomic approach by mass spectrometry combined with neuronal network analysis (i.e. Cytoscape). The metal stress had a greater impact on molecular diversity than on the number of phenolic compounds. The prevalence of sulfur- and nitrogen-rich phenolic compounds were found in Cd- and Cu-amended cultures. Together these results confirm the impact of metallic stress on phenolic compounds production, which could be utilized to assess the metal contamination in natural waters.
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Sharaf A, De Michele R, Sharma A, Fakhari S, Oborník M. Transcriptomic Analysis Reveals the Roles of Detoxification Systems in Response to Mercury in Chromera velia. Biomolecules 2019; 9:E647. [PMID: 31653042 PMCID: PMC6920818 DOI: 10.3390/biom9110647] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/15/2019] [Accepted: 10/18/2019] [Indexed: 01/07/2023] Open
Abstract
Heavy metal pollution is an increasing global concern. Among heavy metals, mercury (Hg) is especially dangerous because of its massive release into the environment and high toxicity, especially for aquatic organisms. The molecular response mechanisms of algae to Hg exposure are mostly unknown. Here, we combine physiological, biochemical, and transcriptomic analysis to provide, for the first time, a comprehensive view on the pathways activated in Chromera velia in response to toxic levels of Hg. Production of hydrogen peroxide and superoxide anion, two reactive oxygen species (ROS), showed opposite patterns in response to Hg2+ while reactive nitrogen species (RNS) levels did not change. A deep RNA sequencing analysis generated a total of 307,738,790 high-quality reads assembled in 122,874 transcripts, representing 89,853 unigenes successfully annotated in databases. Detailed analysis of the differently expressed genes corroborates the biochemical results observed in ROS production and suggests novel putative molecular mechanisms in the algal response to Hg2+. Moreover, we indicated that important transcription factor (TF) families associated with stress responses differentially expressed in C. velia cultures under Hg stress. Our study presents the first in-depth transcriptomic analysis of C. velia, focusing on the expression of genes involved in different detoxification defense systems in response to heavy metal stress.
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Affiliation(s)
- Abdoallah Sharaf
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic.
- Genetic Department, Faculty of Agriculture, Ain Shams University, Cairo 11241, Egypt.
| | - Roberto De Michele
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR) of Italy, 90129 Palermo, Italy.
| | - Ayush Sharma
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic.
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic.
| | - Safieh Fakhari
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR) of Italy, 90129 Palermo, Italy.
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic.
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic.
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Alcántara C, Coll-Marqués JM, Jadán-Piedra C, Vélez D, Devesa V, Zúñiga M, Monedero V. Polyphosphate in Lactobacillus and Its Link to Stress Tolerance and Probiotic Properties. Front Microbiol 2018; 9:1944. [PMID: 30245671 PMCID: PMC6137179 DOI: 10.3389/fmicb.2018.01944] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 07/31/2018] [Indexed: 12/29/2022] Open
Abstract
The synthesis of the inorganic polymer polyphosphate (poly-P) in bacteria has been linked to stress survival and to the capacity of some strains to sequester heavy metals. In addition, synthesis of poly-P by certain strains of probiotic lactobacilli has been evidenced as a probiotic mechanism due to the homeostatic properties of this compound at the intestinal epithelium. We analyzed the link between poly-P synthesis, stress response, and mercury toxicity/accumulation by comparing wild-type strains of Lactobacillus and their corresponding mutants devoid of poly-P synthesis capacity (defective in the poly-P kinase, ppk, gene). Results showed that resistance to salt (NaCl) and acidic (pH 4) stresses upon ppk mutation was affected in Lactobacillus casei, while no effect was observed in two different Lactobacillus plantarum strains. Inorganic [Hg(II)] and organic (CH3Hg) mercury toxicity was generally increased upon ppk mutation, but no influence was seen on the capacity to retain both mercurial forms by the bacteria. Notwithstanding, the culture supernatants of ppk-defective L. plantarum strains possessed a diminished capacity to induce HSP27 expression, a marker for cell protection, in cultured Caco-2 cells compared to wild-type strains. In summary, our results illustrate that the role of poly-P in stress tolerance can vary between strains and they reinforce the idea of probiotic-derived poly-P as a molecule that modulates host-signaling pathways. They also question the relevance of this polymer to the capacity to retain mercury of probiotics.
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Affiliation(s)
- Cristina Alcántara
- Laboratory of Lactic Acid Bacteria and Probiotics, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - José M Coll-Marqués
- Laboratory of Lactic Acid Bacteria and Probiotics, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Carlos Jadán-Piedra
- Trace Elements Group, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Dinoraz Vélez
- Trace Elements Group, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Vicenta Devesa
- Trace Elements Group, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Manuel Zúñiga
- Laboratory of Lactic Acid Bacteria and Probiotics, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Vicente Monedero
- Laboratory of Lactic Acid Bacteria and Probiotics, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
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Biochemistry and Physiology of Heavy Metal Resistance and Accumulation in Euglena. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 979:91-121. [PMID: 28429319 DOI: 10.1007/978-3-319-54910-1_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Free-living microorganisms may become suitable models for removal of heavy metals from polluted water bodies, sediments, and soils by using and enhancing their metal accumulating abilities. The available research data indicate that protists of the genus Euglena are a highly promising group of microorganisms to be used in bio-remediation of heavy metal-polluted aerobic and anaerobic acidic aquatic environments. This chapter analyzes the variety of biochemical mechanisms evolved in E. gracilis to resist, accumulate and remove heavy metals from the environment, being the most relevant those involving (1) adsorption to the external cell pellicle; (2) intracellular binding by glutathione and glutathione polymers, and their further compartmentalization as heavy metal-complexes into chloroplasts and mitochondria; (3) polyphosphate biosynthesis; and (4) secretion of organic acids. The available data at the transcriptional, kinetic and metabolic levels on these metabolic/cellular processes are herein reviewed and analyzed to provide mechanistic basis for developing genetically engineered Euglena cells that may have a greater removal and accumulating capacity for bioremediation and recycling of heavy metals.
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García-García JD, Sánchez-Thomas R, Moreno-Sánchez R. Bio-recovery of non-essential heavy metals by intra- and extracellular mechanisms in free-living microorganisms. Biotechnol Adv 2016; 34:859-873. [PMID: 27184302 DOI: 10.1016/j.biotechadv.2016.05.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 05/10/2016] [Accepted: 05/12/2016] [Indexed: 01/29/2023]
Abstract
Free-living microorganisms may become suitable models for recovery of non-essential and essential heavy metals from wastewater bodies and soils by using and enhancing their accumulating and/or leaching abilities. This review analyzes the variety of different mechanisms developed mainly in bacteria, protists and microalgae to accumulate heavy metals, being the most relevant those involving phytochelatin and metallothionein biosyntheses; phosphate/polyphosphate metabolism; compartmentalization of heavy metal-complexes into vacuoles, chloroplasts and mitochondria; and secretion of malate and other organic acids. Cyanide biosynthesis for extra-cellular heavy metal bioleaching is also examined. These metabolic/cellular processes are herein analyzed at the transcriptional, kinetic and metabolic levels to provide mechanistic basis for developing genetically engineered microorganisms with greater capacities and efficiencies for heavy metal recovery, recycling of heavy metals, biosensing of metal ions, and engineering of metalloenzymes.
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Affiliation(s)
- Jorge D García-García
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México D.F. 14080, México.
| | - Rosina Sánchez-Thomas
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México D.F. 14080, México
| | - Rafael Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México D.F. 14080, México
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Santiago-Martínez MG, Lira-Silva E, Encalada R, Pineda E, Gallardo-Pérez JC, Zepeda-Rodriguez A, Moreno-Sánchez R, Saavedra E, Jasso-Chávez R. Cadmium removal by Euglena gracilis is enhanced under anaerobic growth conditions. JOURNAL OF HAZARDOUS MATERIALS 2015; 288:104-112. [PMID: 25698571 DOI: 10.1016/j.jhazmat.2015.02.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 06/04/2023]
Abstract
The facultative protist Euglena gracilis, a heavy metal hyper-accumulator, was grown under photo-heterotrophic and extreme conditions (acidic pH, anaerobiosis and with Cd(2+)) and biochemically characterized. High biomass (8.5×10(6)cellsmL(-1)) was reached after 10 days of culture. Under anaerobiosis, photosynthetic activity built up a microaerophilic environment of 0.7% O₂, which was sufficient to allow mitochondrial respiratory activity: glutamate and malate were fully consumed, whereas 25-33% of the added glucose was consumed. In anaerobic cells, photosynthesis but not respiration was activated by Cd(2+) which induced higher oxidative stress. Malondialdehyde (MDA) levels were 20 times lower in control cells under anaerobiosis than in aerobiosis, although Cd(2+) induced a higher MDA production. Cd(2+) stress induced increased contents of chelating thiols (cysteine, glutathione and phytochelatins) and polyphosphate. Biosorption (90%) and intracellular accumulation (30%) were the mechanisms by which anaerobic cells removed Cd(2+) from medium, which was 36% higher versus aerobic cells. The present study indicated that E. gracilis has the ability to remove Cd(2+) under anaerobic conditions, which might be advantageous for metal removal in sediments from polluted water bodies or bioreactors, where the O₂ concentration is particularly low.
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Affiliation(s)
| | | | - Rusely Encalada
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Mexico
| | - Erika Pineda
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Mexico
| | | | | | | | - Emma Saavedra
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Mexico
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Krajčovič J, Schwartzbach SD. Euglenoid flagellates: a multifaceted biotechnology platform. J Biotechnol 2014; 202:135-45. [PMID: 25527385 DOI: 10.1016/j.jbiotec.2014.11.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 11/12/2014] [Accepted: 11/20/2014] [Indexed: 01/08/2023]
Abstract
Euglenoid flagellates are mainly fresh water protists growing in highly diverse environments making them well-suited for a multiplicity of biotechnology applications. Phototrophic euglenids possesses complex chloroplasts of green algal origin bounded by three membranes. Euglena nuclear and plastid genome organization, gene structure and gene expression are distinctly different from other organisms. Our observations on the model organism Euglena gracilis indicate that transcription of both the plastid and nuclear genome is insensitive to environmental changes and that gene expression is regulated mainly at the post-transcriptional level. Euglena plastids have been proposed as a site for the production of proteins and value added metabolites of biotechnological interest. Euglena has been shown to be a suitable protist species to be used for production of several compounds that are used in the production of cosmeceuticals and nutraceuticals, such as α-tocopherol, wax esters, polyunsaturated fatty acids, biotin and tyrosine. The storage polysaccharide, paramylon, has immunostimulatory properties and has shown a promise for biomaterials production. Euglena biomass can be used as a nutritional supplement in aquaculture and in animal feed. Diverse applications of Euglena in environmental biotechnology include ecotoxicological risk assessment, heavy metal bioremediation, bioremediation of industrial wastewater and contaminated water.
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Affiliation(s)
- Juraj Krajčovič
- Department of Genetics, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovakia.
| | - Steven D Schwartzbach
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152-3560, USA
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Lira-Silva E, Ramírez-Lima IS, Olín-Sandoval V, García-García JD, García-Contreras R, Moreno-Sánchez R, Jasso-Chávez R. Removal, accumulation and resistance to chromium in heterotrophic Euglena gracilis. JOURNAL OF HAZARDOUS MATERIALS 2011; 193:216-224. [PMID: 21831522 DOI: 10.1016/j.jhazmat.2011.07.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 06/16/2011] [Accepted: 07/13/2011] [Indexed: 05/31/2023]
Abstract
The removal, uptake and toxicity of chromium in Euglena gracilis cultured in absence and presence of malate with Cr(VI) or Cr(III) was evaluated. The malate extrusion and the extra- and intracellular Cr(VI) reduction capacity were determined and the contents of molecules with thiol group and ascorbate were also evaluated. Absence of malate in the medium decreased cell growth, increased Cr(III) toxicity, induced faster Cr(VI) disappearance from medium, and increased intracellular and intramitochondrial chromium accumulation. Both chromium species induced soluble and particulate ascorbate-dependent chromate reductase activities. Cells also secreted large amounts of malate and increased intracellular contents of thiol-molecules to bind extracellular and intracellular Cr(III), respectively. The former process was supported by significant increase in malate-producing enzyme activities and the assessment of the Cr-complexes indicated the in situ formation with thiol-molecules. The present results establish new paradigms regarding chromium stress on algae-like microorganisms: (i) Cr(III) may be more toxic than Cr(VI), depending on the culture (or environmental) conditions; (ii) several simultaneous mechanisms are turned on to inactivate chromium species and their toxic effects. These mechanisms, now well understood may further optimize, by genetically modifying E. gracilis, and facilitate the development of strategies for using this protist as potential bio-remediator of chromium-polluted water systems.
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Affiliation(s)
- Elizabeth Lira-Silva
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Juan Badiano # 1, Sección XVI, Tlalpan, México DF 14080, Mexico
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Shirabe T, Omura M, Osaki Y, Yoshimura E. Increased resistance to Cd(II) in the primitive red algae Cyanidioschyzon merolae. Biol Trace Elem Res 2010; 138:13-21. [PMID: 20084468 DOI: 10.1007/s12011-009-8598-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
Abstract
Growth of Cyanidioschyzon merolae was inhibited depending on the cadmium(II) concentration in the culture medium. Although a lower level (0.01 mM) of Cd(II) inhibited growth by a factor of 0.5, higher levels (0.1 and 1 mM) induced lag periods of 10-14 days. Algal cells pretreated with 1 mM Cd(II) for 27 days grew steadily in 1 mM Cd(II) without the lag period, demonstrating that the cells became Cd(II) resistant (CdR). Cells remained resistant after four cycles (7 days per cycle) of washing and re-growing in medium without Cd(II), while intracellular Cd(II) decreased to undetectable levels. These results suggest that the Cd(II)-resistant phenotype is heritable. This phenomena may be attributable to the presence of genetic inhomogeneity in the wild-type cell populations or to mutagenesis caused by Cd(II) stress. Intracellular Cd(II) levels significantly decreased in the CdR phenotype compared to the wild-type cells, indicating that resistant cells may have a defective gene that codes for Cd(II)-uptake protein or the ability to secrete Cd(II).
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Affiliation(s)
- Tomoo Shirabe
- Department of Applied Biological Chemistry, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
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Jasso-Chávez R, Pacheco-Rosales A, Lira-Silva E, Gallardo-Pérez JC, García N, Moreno-Sánchez R. Toxic effects of Cr(VI) and Cr(III) on energy metabolism of heterotrophic Euglena gracilis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 100:329-338. [PMID: 20851473 DOI: 10.1016/j.aquatox.2010.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Revised: 08/10/2010] [Accepted: 08/17/2010] [Indexed: 05/29/2023]
Abstract
To assess the toxic effect of Cr on energy metabolism, heterotrophic Euglena gracilis was grown in a medium that prompts high yield biomass and in the presence of different Cr(VI) or Cr(III) concentrations. The cell growth IC₅₀ value was 12 and >250μM for Cr(VI) and Cr(III), respectively; in these cells chromium was accumulated and a fraction compartmentalized into mitochondria, and synthesis of cysteine and glutathione was induced. Respiration of control isolated mitochondria was strongly inhibited by added Cr(VI) or Cr(III) with L-lactate or succinate as substrates. In turn, cellular and mitochondrial respiration, respiratory Complexes I, III and IV, glycolysis and cytosolic NAD(+)-alcohol and -lactate dehydrogenases from cells cultured with Cr(VI) were significantly lower than control, whereas AOX and external NADH dehydrogenase activities were unaltered or increased, respectively. Addition of Cr(VI) or Cr(III) to isolated mitochondria or cytosol from control- or Cr(VI)-grown cells induced inhibition of respiration, respiratory Complexes III, IV and AOX, and glycolytic pyruvate kinase; whereas Complex I, external NADH dehydrogenase, and other glycolytic enzymes were unaffected. Protein contents of mitochondrial Complexes I, III, IV and V, and ANT were diminished in Cr(VI)-grown cells. Decreased respiration and glycolysis induced by Cr(VI) resulted in lower cellular ATP content. Results suggested that Cr(VI) cytotoxicity altered gene expression (as widely documented) and hence enzyme content, and induced oxidative stress, but it was also related with direct enzyme inhibition; Cr(III) was also cytotoxic although at higher concentrations. These findings establish new paradigms for chromium toxicity: Cr(VI) direct enzyme inhibition and non-innocuous external Cr(III) toxicity.
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Affiliation(s)
- Ricardo Jasso-Chávez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Tlalpan, México D.F., Mexico.
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p38 MAPK as a signal transduction component of heavy metals stress in Euglena gracilis. Arch Microbiol 2008; 191:47-54. [DOI: 10.1007/s00203-008-0427-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 08/05/2008] [Accepted: 08/18/2008] [Indexed: 10/21/2022]
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Torres MA, Barros MP, Campos SCG, Pinto E, Rajamani S, Sayre RT, Colepicolo P. Biochemical biomarkers in algae and marine pollution: a review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2008; 71:1-15. [PMID: 18599121 DOI: 10.1016/j.ecoenv.2008.05.009] [Citation(s) in RCA: 276] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 03/11/2008] [Accepted: 05/09/2008] [Indexed: 05/09/2023]
Abstract
Environmental pollution by organic compounds and metals became extensive as mining and industrial activities increased in the 19th century and have intensified since then. Environmental pollutants originating from diverse anthropogenic sources have been known to possess adverse values capable of degrading the ecological integrity of marine environment. The consequences of anthropogenic contamination of marine environments have been ignored or poorly characterized with the possible exception of coastal and estuarine waters close to sewage outlets. Monitoring the impact of pollutants on aquatic life forms is challenging due to the differential sensitivities of organisms to a given pollutant, and the inability to assess the long-term effects of persistent pollutants on the ecosystem as they are bio-accumulated at higher trophic levels. Marine microalgae are particularly promising indicator species for organic and inorganic pollutants since they are typically the most abundant life forms in aquatic environments and occupy the base of the food chain. We review the effects of pollutants on the cellular biochemistry of microalgae and the biochemical mechanisms that microalgae use to detoxify or modify pollutants. In addition, we evaluate the potential uses of microalgae as bioindicator species as an early sentinel in polluted sites.
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Affiliation(s)
- Moacir A Torres
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, SP, Brazil
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Shibagaki N, Grossman A. The State of Sulfur Metabolism in Algae: From Ecology to Genomics. SULFUR METABOLISM IN PHOTOTROPHIC ORGANISMS 2008. [DOI: 10.1007/978-1-4020-6863-8_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Rodríguez-Zavala JS, García-García JD, Ortiz-Cruz MA, Moreno-Sánchez R. Molecular mechanisms of resistance to heavy metals in the protist Euglena gracilis. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2007; 42:1365-78. [PMID: 17680475 DOI: 10.1080/10934520701480326] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The biochemical mechanisms of resistance to several heavy metals, which are associated with their accumulation (binding by high-affinity chelating molecules such as thiol-compounds together with their compartmentalization into organelles), are analyzed for the photosynthetic, free-living protist Euglena gracilis. The complete understanding of these mechanisms may facilitate the rational design of strategies for bioremediation of heavy metal polluted water and soil systems.
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Deloménie C, Foti E, Floch E, Diderot V, Porquet D, Dupuy C, Bonaly J. A new homolog of FocA transporters identified in cadmium-resistant Euglena gracilis. Biochem Biophys Res Commun 2007; 358:455-61. [PMID: 17499216 DOI: 10.1016/j.bbrc.2007.04.145] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Accepted: 04/20/2007] [Indexed: 10/23/2022]
Abstract
To better understand the cellular mechanism of stress resistance to various pollutants (cadmium, pentachlorophenol), we undertook a survey of the Euglena gracilis transcriptome by mRNA differential display and cDNA cloning. We performed a real-time RT-PCR analysis upon four selected genes. One of them significantly changed its expression level in response to stress treatments: B25 gene was overexpressed in Cd-resistant cells whereas it was down-regulated in PCP-adapted cells. By Race assays we obtained for B25 a 1093bp cDNA. The deduced protein was identified as a bacterial formate/nitrite transporter (FocA) homolog and the gene was named EgFth. From all the data, we concluded that EgFth overexpression was related to chronic exposure to cadmium.
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Affiliation(s)
- Claudine Deloménie
- IFR 141, Plateforme Transcriptome, Faculté de Pharmacie, Université Paris-Sud, 5 rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France
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Mendoza-Cózatl DG, Rodríguez-Zavala JS, Rodríguez-Enríquez S, Mendoza-Hernandez G, Briones-Gallardo R, Moreno-Sánchez R. Phytochelatin-cadmium-sulfide high-molecular-mass complexes of Euglena gracilis. FEBS J 2006; 273:5703-13. [PMID: 17212785 DOI: 10.1111/j.1742-4658.2006.05558.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-molecular-mass PC complexes (PC-HMWCs) constituted by phytochelatins (PCs), cadmium and sulfide are synthesized by several organisms after exposure to cadmium. In this study, PC-HMWCs were isolated from photoheterotrophic Euglena gracilis and purified to homogeneity, resulting in compounds of molecular mass 50-380 kDa depending on the CdCl2 and sulfate concentrations in the culture medium. In contrast with plants and some yeasts, PC-HMWCs from E. gracilis mainly comprise (57-75%) monothiol molecules (Cys, gamma-glutamylcysteine, GSH) and, to a lesser extent (25-43%), PCs. A similar acid-soluble thiol compound composition was found in whole cell extracts. The -SH/Cd2+ and S2-/Cd2+ ratios found in purified PC-HMWCs were 1.5 and 1.8, respectively; the (-SH + S2-)/Cd2+ ratio was 3.2. PC-HMWCs of molecular mass 60 and 100 kDa were also localized inside Percoll-purified chloroplasts, in which cadmium and PCs were mainly compartmentalized. Cadmium and sulfur-rich clusters with similar sulfur/cadmium stoichiometries to those of the purified PC-HMWCs were detected in the chloroplast and throughout the cell by energy dispersive microanalysis and atomic resolution electron microscopy. The presence of PC-HMWCs in primitive photosynthetic eukaryotes such as the protist, E. gracilis, suggests that their function as the final cadmium-storage-inactivation process is widespread. Their particular intracellular localization suggests that chloroplasts may play a major role in the cadmium-resistance mechanism in organisms lacking a plant-like vacuole.
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