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Muñoz-Villagrán C, Acevedo-Arbunic J, Härtig E, Issotta F, Mascayano C, Jahn D, Jahn M, Levicán G. The Thioredoxin Fold Protein (TFP2) from Extreme Acidophilic Leptospirillum sp. CF-1 Is a Chaperedoxin-like Protein That Prevents the Aggregation of Proteins under Oxidative Stress. Int J Mol Sci 2024; 25:6905. [PMID: 39000017 PMCID: PMC11241051 DOI: 10.3390/ijms25136905] [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: 05/06/2024] [Revised: 06/13/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024] Open
Abstract
Extreme acidophilic bacteria like Leptospirillum sp. require an efficient enzyme system to counteract strong oxygen stress conditions in their natural habitat. The genome of Leptospirillum sp. CF-1 encodes the thioredoxin-fold protein TFP2, which exhibits a high structural similarity to the thioredoxin domain of E. coli CnoX. CnoX from Escherichia coli is a chaperedoxin that protects protein substrates from oxidative stress conditions using its holdase function and a subsequent transfer to foldase chaperones for refolding. Recombinantly produced and purified Leptospirillum sp. TFP2 possesses both thioredoxin and chaperone holdase activities in vitro. It can be reduced by thioredoxin reductase (TrxR). The tfp2 gene co-locates with genes for the chaperone foldase GroES/EL on the chromosome. The "tfp2 cluster" (ctpA-groES-groEL-hyp-tfp2-recN) was found between 1.9 and 8.8-fold transcriptionally up-regulated in response to 1 mM hydrogen peroxide (H2O2). Leptospirillum sp. tfp2 heterologously expressed in E. coli wild type and cnoX mutant strains lead to an increased tolerance of these E. coli strains to H2O2 and significantly reduced intracellular protein aggregates. Finally, a proteomic analysis of protein aggregates produced in E. coli upon exposition to oxidative stress with 4 mM H2O2, showed that Leptospirillum sp. tfp2 expression caused a significant decrease in the aggregation of 124 proteins belonging to fifteen different metabolic categories. These included several known substrates of DnaK and GroEL/ES. These findings demonstrate that Leptospirillum sp. TFP2 is a chaperedoxin-like protein, acting as a key player in the control of cellular proteostasis under highly oxidative conditions that prevail in extreme acidic environments.
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Affiliation(s)
- Claudia Muñoz-Villagrán
- Laboratorio de Microbiología Básica y Aplicada, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile
| | - Javiera Acevedo-Arbunic
- Laboratorio de Microbiología Básica y Aplicada, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile
| | - Elisabeth Härtig
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr 7, 38106 Braunschweig, Germany; (E.H.)
| | - Francisco Issotta
- Departamento Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica, Santiago 8331150, Chile
| | - Carolina Mascayano
- Laboratorio de Simulación Computacional y Diseño Racional de Fármacos, Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile
| | - Dieter Jahn
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr 7, 38106 Braunschweig, Germany; (E.H.)
- Braunschweig Integrated Centre of Systems Biology BRICS, Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Martina Jahn
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr 7, 38106 Braunschweig, Germany; (E.H.)
| | - Gloria Levicán
- Laboratorio de Microbiología Básica y Aplicada, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile
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Arias D, Zepeda V, Nancucheo I, Saldaña M, Galleguillos PA. Osmotic response in Leptospirillum ferriphilum isolated from an industrial copper bioleaching environment to sulfate. Front Microbiol 2024; 15:1369244. [PMID: 38855770 PMCID: PMC11157003 DOI: 10.3389/fmicb.2024.1369244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 05/08/2024] [Indexed: 06/11/2024] Open
Abstract
Iron and sulfur-oxidizing microorganisms play important roles in several natural and industrial processes. Leptospirillum (L.) ferriphilum, is an iron-oxidizing microorganism with a remarkable adaptability to thrive in extreme acidic environments, including heap bioleaching processes, acid mine drainage (AMD) and natural acidic water. A strain of L. ferriphilum (IESL25) was isolated from an industrial bioleaching process in northern Chile. This strain was challenged to grow at increasing concentrations of sulfate in order to assess changes in protein expression profiles, cells shape and to determine potential compatible solute molecules. The results unveiled changes in three proteins: succinyl CoA (SCoA) synthetase, isocitrate dehydrogenase (IDH) and aspartate semialdehyde dehydrogenase (ASD); which were notably overexpressed when the strain grew at elevated concentrations of sulfate. ASD plays a pivotal role in the synthesis of the compatible solute ectoine, which was identified along with hydroxyectoine by using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF). The relationship between IDH, SCoA, and ectoine production could be due to the TCA cycle, in which both enzymes produce metabolites that can be utilized as precursors or intermediates in the biosynthesis of ectoine. In addition, distinct filamentous cellular morphology in L. ferriphilum IESL25 was observed when growing under sulfate stress conditions. This study highlights a new insight into the possible cellular responses of L. ferriphilum under the presence of high sulfate levels, commonly found in bioleaching of sulfide minerals or AMD environments.
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Affiliation(s)
- Dayana Arias
- Laboratory of Molecular Biology and Applied Microbiology, Centro de Investigación en Fisiología y Medicina de Altura (FIMEDALT), Departamento Biomédico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Víctor Zepeda
- Scientific and Technological Research Centre for Mining Research, CICITEM, Antofagasta, Chile
| | - Ivan Nancucheo
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Concepción, Chile
| | - Manuel Saldaña
- Faculty of Engineering and Architecture, Arturo Prat University, Iquique, Chile
| | - Pedro A. Galleguillos
- Scientific and Technological Research Centre for Mining Research, CICITEM, Antofagasta, Chile
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Arisan D, Moya-Beltrán A, Rojas-Villalobos C, Issotta F, Castro M, Ulloa R, Chiacchiarini PA, Díez B, Martín AJM, Ñancucheo I, Giaveno A, Johnson DB, Quatrini R. Acidithiobacillia class members originating at sites within the Pacific Ring of Fire and other tectonically active locations and description of the novel genus ' Igneacidithiobacillus'. Front Microbiol 2024; 15:1360268. [PMID: 38633703 PMCID: PMC11021618 DOI: 10.3389/fmicb.2024.1360268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/21/2024] [Indexed: 04/19/2024] Open
Abstract
Recent studies have expanded the genomic contours of the Acidithiobacillia, highlighting important lacunae in our comprehension of the phylogenetic space occupied by certain lineages of the class. One such lineage is 'Igneacidithiobacillus', a novel genus-level taxon, represented by 'Igneacidithiobacillus copahuensis' VAN18-1T as its type species, along with two other uncultivated metagenome-assembled genomes (MAGs) originating from geothermally active sites across the Pacific Ring of Fire. In this study, we investigate the genetic and genomic diversity, and the distribution patterns of several uncharacterized Acidithiobacillia class strains and sequence clones, which are ascribed to the same 16S rRNA gene sequence clade. By digging deeper into this data and contributing to novel MAGs emerging from environmental studies in tectonically active locations, the description of this novel genus has been consolidated. Using state-of-the-art genomic taxonomy methods, we added to already recognized taxa, an additional four novel Candidate (Ca.) species, including 'Ca. Igneacidithiobacillus chanchocoensis' (mCHCt20-1TS), 'Igneacidithiobacillus siniensis' (S30A2T), 'Ca. Igneacidithiobacillus taupoensis' (TVZ-G3 TS), and 'Ca. Igneacidithiobacillus waiarikiensis' (TVZ-G4 TS). Analysis of published data on the isolation, enrichment, cultivation, and preliminary microbiological characterization of several of these unassigned or misassigned strains, along with the type species of the genus, plus the recoverable environmental data from metagenomic studies, allowed us to identify habitat preferences of these taxa. Commonalities and lineage-specific adaptations of the seven species of the genus were derived from pangenome analysis and comparative genomic metabolic reconstruction. The findings emerging from this study lay the groundwork for further research on the ecology, evolution, and biotechnological potential of the novel genus 'Igneacidithiobacillus'.
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Affiliation(s)
- Dilanaz Arisan
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
| | - Ana Moya-Beltrán
- Departamento de Informática y Computación, Facultad de Ingeniería, Universidad Tecnológica Metropolitana, Santiago, Chile
| | - Camila Rojas-Villalobos
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Santiago, Chile
| | - Francisco Issotta
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
- Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago, Chile
| | - Matías Castro
- Instituto Milenio de Oceanografía (IMO), Universidad de Concepción, Concepción, Chile
| | - Ricardo Ulloa
- PROBIEN (CCT Patagonia Confluencia-CONICET, UNCo), Facultad de Ingeniería, Departamento de Química, Universidad Nacional del Comahue, Neuquén, Argentina
| | - Patricia A. Chiacchiarini
- PROBIEN (CCT Patagonia Confluencia-CONICET, UNCo), Facultad de Ingeniería, Departamento de Química, Universidad Nacional del Comahue, Neuquén, Argentina
| | - Beatriz Díez
- Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago, Chile
- Center for Climate and Resilience Research (CR), Santiago, Chile
| | - Alberto J. M. Martín
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Santiago, Chile
| | - Iván Ñancucheo
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Lientur, Concepción, Chile
| | - Alejandra Giaveno
- PROBIEN (CCT Patagonia Confluencia-CONICET, UNCo), Facultad de Ingeniería, Departamento de Química, Universidad Nacional del Comahue, Neuquén, Argentina
| | - D. Barrie Johnson
- College of Natural Sciences, Bangor University, Bangor, United Kingdom
- Faculty of Health and Life Sciences, Coventry University, Coventry, United Kingdom
- Natural History Museum, London, United Kingdom
| | - Raquel Quatrini
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
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Huynh D, Haferburg G, Bunk B, Kaschabek SR, Sand W, Schlömann M. Alicyclobacillus sp. SO9, a novel halophilic acidophilic iron-oxidizing bacterium isolated from a tailings-contaminated beach, and its effect on copper extraction from chalcopyrite in the presence of high chloride concentration. Res Microbiol 2024; 175:104150. [PMID: 37926348 DOI: 10.1016/j.resmic.2023.104150] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/26/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
Many acidophilic iron-oxidizing bacteria used in the mining industry for the bioleaching of sulfidic minerals are intolerant to high chloride concentrations, resulting in problems where chloride occurs in the deposit at high concentrations or only seawater is available. In search for strains tolerating such conditions a tetrathionate- and iron-oxidizing bacterium was isolated from a tailings-contaminated beach sample at Portman Bay, Cartagena-La Union mining district, Spain, in the presence of 20 g l-1 (0.34 M) sodium chloride. The isolate was able to form spores, did not grow in the absence of NaCl, and oxidized ferrous iron in the presence of up to 1.5 M (∼87 g l-1) NaCl. Genome sequencing based on a combination of Illumina and PacBio reads revealed two contigs, a circular bacterial chromosome of 5.2 Mbp and a plasmid of 90 kbp, respectively. The chromosome comprised seven different 16S rRNA genes. Submission of the chromosome to the Type (Strain) Genome Server (TYGS) without preselection of similar sequences revealed exclusively type strains of the genus Alicyclobacillus. In the TYGS analyses the respective most similar species were dependent on whether the final tree was derived from just 16S rRNA, from the genomes, or from the proteomes. Thus, TYGS analysis clearly showed that isolate SO9 represents a novel species of the genus Alicyclobacillus. In the presence of artificial seawater with almost 0.6 M chloride, the addition of Alicyclobacillus sp. SO9 improved copper dissolution from chalcopyrite (CuFeS2) compared to abiotic leaching without bacteria. The new isolate SO9, therefore, has potential for bioleaching at elevated chloride concentrations.
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Affiliation(s)
- Dieu Huynh
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
| | - Götz Haferburg
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH Dept. Bioinformatics, IT and Databases, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Stefan R Kaschabek
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
| | - Wolfgang Sand
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
| | - Michael Schlömann
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
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Li M, Wen J. Study on the intracellular adaptative mechanism of Acidithiobacillus caldus MTH-04 to NaCl stress. Microb Cell Fact 2023; 22:218. [PMID: 37880737 PMCID: PMC10599003 DOI: 10.1186/s12934-023-02232-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023] Open
Abstract
To understand the adaptive mechanism of bioleaching microorganism Acidithiobacillus caldus MTH-04, its physiology and metabolic changes at the transcriptional level were systemically studied. The results of growth curves, SO42- content, pH and flow cytometry analyses indicated that the higher the NaCl concentration, the more the strain was inhibited. The transcriptome response of A. caldus to elevated NaCl concentrations included changes in carbon flux, elevated glutathione synthesis, alterations in cell wall and membrane composition, the down-regulation in genes involved in flagellar synthesis and rotation, the reduced energy generation through sulfur oxidation, and the up-regulation in genes involved in DNA and protein repair. Based on the transcriptome results, the effects of proline and glutathione on NaCl adaptation in A. caldus were analyzed separately. We found that either the exogenous addition of proline and glutathione or the intracellular overexpression of the enzymes responsible for the synthesis of these two substances contributed to the enhancement of the adaptive capacity of A. caldus under NaCl stress. The findings offer insight into the design of chloride-based techniques for the bioprocessing of minerals.
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Affiliation(s)
- Min Li
- Key Laboratory of Systems Bioengineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin, China
- Frontier Science Center of Ministry of Education, Tianjin University, Tianjin, China
| | - Jianping Wen
- Key Laboratory of Systems Bioengineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin, China.
- Frontier Science Center of Ministry of Education, Tianjin University, Tianjin, China.
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6
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Majumder A, Sarkar C, Das I, Sk S, Bandyopadhyay S, Mandal S, Bera M. Design, Synthesis and Evaluation of a Series of Zinc(II) Complexes of Anthracene-Affixed Multifunctional Organic Assembly as Potential Antibacterial and Antibiofilm Agents against Methicillin-Resistant Staphylococcus aureus. ACS APPLIED MATERIALS & INTERFACES 2023; 15:22781-22804. [PMID: 37129921 DOI: 10.1021/acsami.2c21899] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A novel class of zinc(II)-based metal complexes, i.e., [Zn2(acdp)(μ-Cl)]·2H2O (1), [Zn2(acdp)(μ-NO3)]·2H2O (2), and [Zn2(acdp)(μ-O2CCF3)]·2H2O (3) (Cl- = chloride; NO3- = nitrate; CF3CO2- = trifluoroacetate) of anthracene-affixed multifunctional organic assembly, H3acdp (H3acdp = N,N'-bis[anthracene-2-ylmethyl]-N,N'-bis[carboxymethyl]-1,3-diaminopropan-2-ol), have emerged as promising antibacterial and antibiofilm agents in the domain of medicinal chemistry. Accordingly, complexes 1-3 were synthesized by utilizing H3acdp in combination with ZnCl2, Zn(NO3)2·6H2O, and Zn(CF3CO2)2·H2O respectively, in the presence of NaOH at ambient temperature. The complexation between H3acdp and Zn2+ was delineated by a combined approach of spectrophotometric and spectrofluorometric titration studies. The stoichiometry of acdp3-/Zn2+ in all three complexes is observed to be 1:2, as confirmed by spectrophotometric/spectrofluorometric titration data. Elemental analysis (C, H, N, Zn), molar conductance, FTIR, UV-vis, and thermoanalytical (TGA/DTA) data were effectively used to characterize these complexes. Besides, the structures of 1-3 were established by density functional theory (DFT) calculation using B3LYP/6-311G, specifying a self-assembled compact geometry with average Zn···Zn separation of 3.4629 Å. All three zinc complexes exhibited significantly high antibacterial and antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA BAA1717). However, complex 1 showed a more recognizable activity than 2 and 3, with minimum inhibitory concentration (MIC) values of 200, 350, and 450 μg/mL, respectively. The antimicrobial activity was tested by employing the minimum inhibitory concentration (MIC) and time-kill assay. The crystal violet (CV) assay and microscopic study were performed to examine the antibiofilm activity. As observed, complexes 1-3 had an effect on the production of extracellular polymeric substance (EPS), biofilm cell-viability, and other virulence factors such as staphyloxanthin and hemolysin production, autoaggregation ability, and microbial cell-surface hydrophobicity. Reactive oxygen species (ROS) generated due to inhibition of staphyloxanthin production in response to 1-3 were also analyzed. Moreover, complexes 1-3 showed an ability to damage the bacterial cell membrane due to accumulation of ROS resulting in DNA leakage. In addition, complexes 1-3 displayed a synergistic/additive activity with a commercially available antibiotic drug, vancomycin, with enhanced antibacterial activity. On the whole, our investigation disclosed that complex 1 could be a promising drug lead and attract much attention to medicinal chemists compared to 2 and 3 from therapeutic aspects.
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Affiliation(s)
- Avishek Majumder
- Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Chandan Sarkar
- Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Indrajit Das
- Department of Microbiology, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Sujan Sk
- Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Shrabasti Bandyopadhyay
- Department of Microbiology, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Supratim Mandal
- Department of Microbiology, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Manindranath Bera
- Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
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7
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Ye Z, Li Y, Zhao Y, Zhang J, Zhu T, Xu F, Li F. Effect of Exogenous Electric Stimulation on the Cardiac Tissue Function In Situ Monitored by Scanning Electrochemical Microscopy. Anal Chem 2023; 95:4634-4643. [PMID: 36787441 DOI: 10.1021/acs.analchem.2c04758] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Cardiac tissue is sensitive to and can be easily damaged by exogenous electric stimulation. However, due to the thermal-electric coeffect and the limitation of in situ and quantitative information on the cardiac tissue function under electric stimulation, the detailed effect and the underlying mechanism of exogenous electric stimulation on the cardiac tissue remain elusive. To address this, in this work, we first constructed an in vitro cardiac tissue model and established a thermal-electric coupled theoretical model for simulating the electric field and temperature distributions around the cardiac tissue, from which we selected the electric field strengths (1.19, 2.37, and 3.39 kV cm-1) and electrical energies (0.001, 0.005, and 0.011 J) for electric stimulations without inducing a thermal effect. Then, we applied electric field stimulations on the cardiac tissue using these parameters and scanning electrochemical microscopy (SECM) to in situ and quantitatively monitor the dynamic changes in the key parameters of the cardiac tissue function, including respiratory activity, membrane permeability, and contraction frequency, after electric field stimulations. The SECM results showed that the oxygen consumption, cell membrane permeability coefficient, and contraction frequency of the cardiac tissue were strongly dependent on electrical energy, especially when the electrical energy was higher than 0.001 J. Our work, for the first time, achieves the in situ and quantitative monitoring of the cardiac tissue function under electric stimulation using SECM, which would provide important references for designing an electric stimulation regime for cardiac tissue engineering and clinical application of electrotherapy.
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Affiliation(s)
- Zhaoyang Ye
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Yabei Li
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China.,School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Yuxiang Zhao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Junjie Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Tong Zhu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Department of Cardiovasology, Xidian Group Hospital, Xi'an 710077, Shaanxi, P. R. China
| | - Feng Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Fei Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China
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8
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Yeap CSY, Nguyen NHA, Spanek R, Too CC, Benes V, Provaznik J, Cernik M, Sevcu A. Dissolved iron released from nanoscale zero-valent iron (nZVI) activates the defense system in bacterium Pseudomonas putida, leading to high tolerance to oxidative stress. JOURNAL OF HAZARDOUS MATERIALS 2022; 439:129627. [PMID: 35872458 DOI: 10.1016/j.jhazmat.2022.129627] [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: 04/28/2022] [Revised: 07/03/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Nanoscale zero-valent iron (nZVI) has increasingly been applied to remediate aquifers polluted by organochlorines or heavy metals. As a result, bacteria in the vicinity of remediate action can be stressed by surplus iron released from nZVI. However, the understanding of the iron stress defense pathways during this process is currently incomplete. Therefore, we aimed to elucidate the physiological and transcriptomic response of the bacterium, Pseudomonas putida NCTC 10936, to 100 mg/L of nZVI and 44.5 µg/L of dissolved iron obtained from nZVI suspension. Cell viability was neither affected by nZVI nor dissolved iron, although the dissolved iron caused stress that altered the cell physiology and caused the generation of smaller cells, whereas cells were elongated in the presence of nZVI. Transcriptomic analysis confirmed the observed stronger physiological effect caused by dissolved iron (in total 3839 differentially expressed genes [DEGs]) than by nZVI (945 DEGs). Dissolved iron (but not nZVI) activated genes involved in oxidative stress-related pathways, antioxidant activity, carbohydrate and energy metabolism, but downregulated genes associated with flagellar assembly proteins and two-component systems involved in sensing external stimuli. As a result, bacteria very effectively faced oxidative insults and cell viability was not affected.
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Affiliation(s)
- Cheryl S Y Yeap
- Institute for Nanomaterials Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 1409/7, 46117 Liberec 1, Czechia; Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 2, 461 17 Liberec 1, Czechia
| | - Nhung H A Nguyen
- Institute for Nanomaterials Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 1409/7, 46117 Liberec 1, Czechia
| | - Roman Spanek
- Institute for Nanomaterials Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 1409/7, 46117 Liberec 1, Czechia; Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 2, 461 17 Liberec 1, Czechia
| | - Chin Chin Too
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, Campus Ledeganck, 9000 Ghent, Belgium
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory of Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jan Provaznik
- Genomics Core Facility, European Molecular Biology Laboratory of Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Miroslav Cernik
- Institute for Nanomaterials Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 1409/7, 46117 Liberec 1, Czechia
| | - Alena Sevcu
- Institute for Nanomaterials Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 1409/7, 46117 Liberec 1, Czechia; Faculty of Science, Humanities and Education, Technical University of Liberec, Studentská 2, 461 17 Liberec 1, Czechia.
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9
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Sand W, Schippers A, Hedrich S, Vera M. Progress in bioleaching: fundamentals and mechanisms of microbial metal sulfide oxidation - part A. Appl Microbiol Biotechnol 2022; 106:6933-6952. [PMID: 36194263 PMCID: PMC9592645 DOI: 10.1007/s00253-022-12168-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 11/30/2022]
Abstract
Abstract Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides’ mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution via oxidation of iron(II) ions and inorganic sulfur compounds. Thereby, the metal sulfide attacking agents iron(III) ions and protons are generated. Cells are active either in a planktonic state or attached to the mineral surface, forming biofilms. This review, as an update of the previous one (Vera et al., 2013a), summarizes some recent discoveries relevant to bioleaching microorganisms, contributing to a better understanding of their lifestyle. These comprise phylogeny, chemical pathways, surface science, biochemistry of iron and sulfur metabolism, anaerobic metabolism, cell–cell communication, molecular biology, and biofilm lifestyle. Recent advances from genetic engineering applied to bioleaching microorganisms will allow in the future to better understand important aspects of their physiology, as well as to open new possibilities for synthetic biology applications of leaching microbial consortia. Key points • Leaching of metal sulfides is strongly enhanced by microorganisms • Biofilm formation and extracellular polymer production influences bioleaching • Cell interactions in mixed bioleaching cultures are key for process optimization
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Affiliation(s)
- Wolfgang Sand
- Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany. .,Faculty of Chemistry, University Duisburg-Essen, Essen, Germany.
| | - Axel Schippers
- Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Hannover, Germany
| | - Sabrina Hedrich
- Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Mario Vera
- Instituto de Ingeniería Biológica y Médica, Escuelas de Ingeniería, Medicina y Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. .,Departamento de Ingeniería Hidráulica y Ambiental, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile.
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10
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Myriam P, Braulio P, Javiera RA, Claudia MV, Omar O, Renato C, Gloria L. Insights into Systems for Iron-Sulfur Cluster Biosynthesis in Acidophilic Microorganisms. J Microbiol Biotechnol 2022; 32:1110-1119. [PMID: 36039043 PMCID: PMC9628965 DOI: 10.4014/jmb.2206.06045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/02/2022] [Accepted: 08/17/2022] [Indexed: 12/15/2022]
Abstract
Fe-S clusters are versatile and essential cofactors that participate in multiple and fundamental biological processes. In Escherichia coli, the biogenesis of these cofactors requires either the housekeeping Isc pathway, or the stress-induced Suf pathway which plays a general role under conditions of oxidative stress or iron limitation. In the present work, the Fe-S cluster assembly Isc and Suf systems of acidophilic Bacteria and Archaea, which thrive in highly oxidative environments, were studied. This analysis revealed that acidophilic microorganisms have a complete set of genes encoding for a single system (either Suf or Isc). In acidophilic Proteobacteria and Nitrospirae, a complete set of isc genes (iscRSUAX-hscBA-fdx), but not genes coding for the Suf system, was detected. The activity of the Isc system was studied in Leptospirillum sp. CF-1 (Nitrospirae). RT-PCR experiments showed that eight candidate genes were co-transcribed and conform the isc operon in this strain. Additionally, RT-qPCR assays showed that the expression of the iscS gene was significantly up-regulated in cells exposed to oxidative stress imposed by 260 mM Fe2(SO4)3 for 1 h or iron starvation for 3 h. The activity of cysteine desulfurase (IscS) in CF-1 cell extracts was also up-regulated under such conditions. Thus, the Isc system from Leptospirillum sp. CF-1 seems to play an active role in stressful environments. These results contribute to a better understanding of the distribution and role of Fe-S cluster protein biogenesis systems in organisms that thrive in extreme environmental conditions.
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Affiliation(s)
- Pérez Myriam
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Paillavil Braulio
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Rivera-Araya Javiera
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Muñoz-Villagrán Claudia
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Orellana Omar
- Universidad de Chile, Facultad de Medicina, Instituto de Ciencias Biomédicas, Laboratorio de Biología Molecular Bacteriana City, 8380453, Chile
| | - Chávez Renato
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Levicán Gloria
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile,Corresponding author Phone: +56-2-27181125 E-mail:
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11
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Dawan J, Ahn J. Bacterial Stress Responses as Potential Targets in Overcoming Antibiotic Resistance. Microorganisms 2022; 10:microorganisms10071385. [PMID: 35889104 PMCID: PMC9322497 DOI: 10.3390/microorganisms10071385] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/03/2022] [Accepted: 07/08/2022] [Indexed: 12/23/2022] Open
Abstract
Bacteria can be adapted to adverse and detrimental conditions that induce general and specific responses to DNA damage as well as acid, heat, cold, starvation, oxidative, envelope, and osmotic stresses. The stress-triggered regulatory systems are involved in bacterial survival processes, such as adaptation, physiological changes, virulence potential, and antibiotic resistance. Antibiotic susceptibility to several antibiotics is reduced due to the activation of stress responses in cellular physiology by the stimulation of resistance mechanisms, the promotion of a resistant lifestyle (biofilm or persistence), and/or the induction of resistance mutations. Hence, the activation of bacterial stress responses poses a serious threat to the efficacy and clinical success of antibiotic therapy. Bacterial stress responses can be potential targets for therapeutic alternatives to antibiotics. An understanding of the regulation of stress response in association with antibiotic resistance provides useful information for the discovery of novel antimicrobial adjuvants and the development of effective therapeutic strategies to control antibiotic resistance in bacteria. Therefore, this review discusses bacterial stress responses linked to antibiotic resistance in Gram-negative bacteria and also provides information on novel therapies targeting bacterial stress responses that have been identified as potential candidates for the effective control of Gram-negative antibiotic-resistant bacteria.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
| | - Juhee Ahn
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea
- Correspondence: ; Tel.: +82-33-250-6564
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12
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Javier RA, Matías R, Alonso F, Renato C, Gloria L. A novel gene from the acidophilic bacterium Leptospirillum sp. CF-1 and its role in oxidative stress and chromate tolerance. Biol Res 2022; 55:19. [PMID: 35525996 PMCID: PMC9080137 DOI: 10.1186/s40659-022-00388-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Background Acidophilic microorganisms like Leptospirillum sp. CF-1 thrive in environments with extremely low pH and high concentrations of dissolved heavy metals that can induce the generation of reactive oxygen species (ROS). Several hypothetical genes and proteins from Leptospirillum sp. CF-1 are known to be up-regulated under oxidative stress conditions. Results In the present work, the function of hypothetical gene ABH19_09590 from Leptospirillum sp. CF-1 was studied. Heterologous expression of this gene in Escherichia coli led to an increase in the ability to grow under oxidant conditions with 5 mM K2CrO4 or 5 mM H2O2. Similarly, a significant reduction in ROS production in E. coli transformed with a plasmid carrying ABH19_09590 was observed after exposure to these oxidative stress elicitors for 30 min, compared to a strain complemented with the empty vector. A co-transcriptional study using RT-PCR showed that ABH19_09590 is contained in an operon, here named the “och” operon, that also contains ABH19_09585, ABH19_09595 and ABH19_09600 genes. The expression of the och operon was significantly up-regulated in Leptospirillum sp. CF-1 exposed to 5 mM K2CrO4 for 15 and 30 min. Genes of this operon potentially encode a NADH:ubiquinone oxidoreductase, a CXXC motif-containing protein likely involved in thiol/disulfide exchange, a hypothetical protein, and a di-hydroxy-acid dehydratase. A comparative genomic analysis revealed that the och operon is a characteristic genetic determinant of the Leptospirillum genus that is not present in other acidophiles. Conclusions Altogether, these results suggest that the och operon plays a protective role against chromate and hydrogen peroxide and is an important mechanism required to face polyextremophilic conditions in acid environments.
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Affiliation(s)
- Rivera-Araya Javier
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Riveros Matías
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Ferrer Alonso
- Núcleo de Química y Bioquímica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Chávez Renato
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Levicán Gloria
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile.
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Rivera-Araya J, Heine T, Chávez R, Schlömann M, Levicán G. Transcriptomic analysis of chloride tolerance in Leptospirillum ferriphilum DSM 14647 adapted to NaCl. PLoS One 2022; 17:e0267316. [PMID: 35486621 PMCID: PMC9053815 DOI: 10.1371/journal.pone.0267316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 04/06/2022] [Indexed: 11/29/2022] Open
Abstract
Chloride ions are toxic for most acidophilic microorganisms. In this study, the chloride tolerance mechanisms in the acidophilic iron-oxidizing bacterium Leptospirillum ferriphilum DSM 14647 adapted to 180 mM NaCl were investigated by a transcriptomic approach. Results showed that 99 genes were differentially expressed in the adapted versus the non-adapted cultures, of which 69 and 30 were significantly up-regulated or down-regulated, respectively. Genes that were up-regulated include carbonic anhydrase, cytochrome c oxidase (ccoN) and sulfide:quinone reductase (sqr), likely involved in intracellular pH regulation. Towards the same end, the cation/proton antiporter CzcA (czcA) was down-regulated. Adapted cells showed a higher oxygen consumption rate (2.2 x 10−9 ppm O2 s-1cell-1) than non-adapted cells (1.2 x 10−9 ppm O2 s-1cell-1). Genes coding for the antioxidants flavohemoprotein and cytochrome c peroxidase were also up-regulated. Measurements of the intracellular reactive oxygen species (ROS) level revealed that adapted cells had a lower level than non-adapted cells, suggesting that detoxification of ROS could be an important strategy to withstand NaCl. In addition, data analysis revealed the up-regulation of genes for Fe-S cluster biosynthesis (iscR), metal reduction (merA) and activation of a cellular response mediated by diffusible signal factors (DSFs) and the second messenger c-di-GMP. Several genes related to the synthesis of lipopolysaccharide and peptidoglycan were consistently down-regulated. Unexpectedly, the genes ectB, ectC and ectD involved in the biosynthesis of the compatible solutes (hydroxy)ectoine were also down-regulated. In line with these findings, although hydroxyectoine reached 20 nmol mg-1 of wet biomass in non-adapted cells, it was not detected in L. ferriphilum adapted to NaCl, suggesting that this canonical osmotic stress response was dispensable for salt adaptation. Differentially expressed transcripts and experimental validations suggest that adaptation to chloride in acidophilic microorganisms involves a multifactorial response that is different from the response in other bacteria studied.
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Affiliation(s)
- Javier Rivera-Araya
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Thomas Heine
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Renato Chávez
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Michael Schlömann
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Gloria Levicán
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
- * E-mail:
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Boase K, González C, Vergara E, Neira G, Holmes D, Watkin E. Prediction and Inferred Evolution of Acid Tolerance Genes in the Biotechnologically Important Acidihalobacter Genus. Front Microbiol 2022; 13:848410. [PMID: 35516430 PMCID: PMC9062700 DOI: 10.3389/fmicb.2022.848410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/28/2022] [Indexed: 11/18/2022] Open
Abstract
Acidihalobacter is a genus of acidophilic, gram-negative bacteria known for its ability to oxidize pyrite minerals in the presence of elevated chloride ions, a capability rare in other iron-sulfur oxidizing acidophiles. Previous research involving Acidihalobacter spp. has focused on their applicability in saline biomining operations and their genetic arsenal that allows them to cope with chloride, metal and oxidative stress. However, an understanding of the molecular adaptations that enable Acidihalobacter spp. to thrive under both acid and chloride stress is needed to provide a more comprehensive understanding of how this genus can thrive in such extreme biomining conditions. Currently, four genomes of the Acidihalobacter genus have been sequenced: Acidihalobacter prosperus DSM 5130T, Acidihalobacter yilgarnensis DSM 105917T, Acidihalobacter aeolianus DSM 14174T, and Acidihalobacter ferrooxydans DSM 14175T. Phylogenetic analysis shows that the Acidihalobacter genus roots to the Chromatiales class consisting of mostly halophilic microorganisms. In this study, we aim to advance our knowledge of the genetic repertoire of the Acidihalobacter genus that has enabled it to cope with acidic stress. We provide evidence of gene gain events that are hypothesized to help the Acidihalobacter genus cope with acid stress. Potential acid tolerance mechanisms that were found in the Acidihalobacter genomes include multiple potassium transporters, chloride/proton antiporters, glutamate decarboxylase system, arginine decarboxylase system, urease system, slp genes, squalene synthesis, and hopanoid synthesis. Some of these genes are hypothesized to have entered the Acidihalobacter via vertical decent from an inferred non-acidophilic ancestor, however, horizontal gene transfer (HGT) from other acidophilic lineages is probably responsible for the introduction of many acid resistance genes.
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Affiliation(s)
- Katelyn Boase
- Curtin Medical School, Curtin University, Perth, WA, Australia
| | - Carolina González
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Santiago, Chile
| | - Eva Vergara
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Santiago, Chile
| | - Gonzalo Neira
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Santiago, Chile
| | - David Holmes
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencias, Universidad San Sebastián, Santiago, Chile
- *Correspondence: David S. Holmes,
| | - Elizabeth Watkin
- Curtin Medical School, Curtin University, Perth, WA, Australia
- Elizabeth Watkin,
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15
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Examining the Osmotic Response of Acidihalobacter aeolianus after Exposure to Salt Stress. Microorganisms 2021; 10:microorganisms10010022. [PMID: 35056469 PMCID: PMC8781986 DOI: 10.3390/microorganisms10010022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/13/2021] [Accepted: 12/21/2021] [Indexed: 11/25/2022] Open
Abstract
Acidihalobacter aeolianus is an acidophilic, halo-tolerant organism isolated from a marine environment near a hydrothermal vent, an ecosystem whereby levels of salinity and total dissolved salts are constantly fluctuating creating ongoing cellular stresses. In order to survive these continuing changes, the synthesis of compatible solutes—also known as organic osmolytes—is suspected to occur, aiding in minimising the overall impact of environmental instability. Previous studies on A. aeolianus identified genes necessary for the accumulation of proline, betaine and ectoine, which are known to act as compatible solutes in other halophilic species. In this study, the impact of increasing the osmotic stress as well as the toxic ion effect was investigated by subjecting A. aeolianus to concentrations of NaCl and MgSO4 up to 1.27 M. Exposure to high concentrations of Cl− resulted in the increase of ectC expression in log-phase cells with a corresponding accumulation of ectoine at stationary phase. Osmotic stress via MgSO4 exposure did not trigger the same up-regulation of ectC or accumulation of ectoine, indicating the transcriptionally regulated response against osmotic stress was induced by chloride toxicity. These findings have highlighted how the adaptive properties of halo-tolerant organisms in acidic environments are likely to differ and are dependent on the initial stressor.
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16
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Glutathione synthetase overexpression in Acidithiobacillus ferrooxidans improves halotolerance of iron oxidation. Appl Environ Microbiol 2021; 87:e0151821. [PMID: 34347521 DOI: 10.1128/aem.01518-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Acidithiobacillus ferrooxidans are well-studied iron- and sulfur-oxidizing acidophilic chemolithoautotrophs that are exploited for their ability to participate in the bioleaching of metal sulfides. Here, we overexpressed the endogenous glutamate-cysteine ligase and glutathione synthetase genes in separate strains and found that glutathione synthetase overexpression increased intracellular glutathione levels. We explored the impact of pH on the halotolerance of iron oxidation in wild type and engineered cultures. The increase in glutathione allowed the modified cells to grow under salt concentrations and pH conditions that are fully inhibitory to wild type cells. Furthermore, we found that improved iron oxidation ability in the presence of chloride also resulted in higher levels of intracellular ROS in the strain. These results indicate that glutathione overexpression can be used to increase halotolerance in A. ferrooxidans and would likely be a useful strategy on other acidophilic bacteria. Importance The use of acidophilic bacteria in the hydrometallurgical processing of sulfide ores can enable many benefits including the potential reduction of environmental impacts. The cells involved in bioleaching tend to have limited halotolerance, and increased halotolerance could enable several benefits, including a reduction in the need for the use of fresh water resources. We show that the genetic modification of A. ferrooxidans for the overproduction of glutathione is a promising strategy to enable cells to resist the oxidative stress that can occur during growth in the presence of salt.
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Farías R, Norambuena J, Ferrer A, Camejo P, Zapata C, Chávez R, Orellana O, Levicán G. Redox stress response and UV tolerance in the acidophilic iron-oxidizing bacteria Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans. Res Microbiol 2021; 172:103833. [PMID: 33901608 DOI: 10.1016/j.resmic.2021.103833] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 11/16/2022]
Abstract
The oxidative stress response represents a sum of antioxidative mechanisms that are essential for determining the adaptation and abundance of microorganisms in the environment. Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans are chemolithotrophic bacteria that obtain their energy from the oxidation of ferrous ion. Both microorganisms are important for bioleaching of sulfidic ores and both are tolerant to high levels of heavy metals and other factors that can induce oxidative stress. In this work, we compared the tolerance and response of L. ferriphilum and At. ferrooxidans to Fe3+, H2O2, K2CrO4, and UV-C radiation. We evaluated growth, generation of reactive oxygen species (ROS), oxidative damage to lipid membranes and DNA, and the activity of antioxidative proteins in cells exposed to these stressors. L. ferriphilum had higher cell density, lower ROS content and less lipid and DNA damage than At. ferrooxidans. Consistent with this, the activity levels of thioredoxin and superoxide dismutase in L. ferriphilum were upregulated and higher than in At. ferrooxidans. This indicated that L. ferriphilum has a higher capacity to respond to oxidative stress and to manage redox homeostasis. This capacity could largely contribute to the high abundance of this species in natural and anthropogenic sites.
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Affiliation(s)
- Ricardo Farías
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago, Chile
| | - Javiera Norambuena
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago, Chile
| | - Alonso Ferrer
- Núcleo de Química y Bioquímica, Facultad de Estudios Interdisciplinarios, Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago, Chile
| | - Pamela Camejo
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago, Chile
| | - Claudia Zapata
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago, Chile
| | - Renato Chávez
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago, Chile
| | - Omar Orellana
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Gloria Levicán
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago, Chile.
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18
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Huynh D, Kaschabek SR, Schlömann M. Effect of inoculum history, growth substrates and yeast extract addition on inhibition of Sulfobacillus thermosulfidooxidans by NaCl. Res Microbiol 2020; 171:252-259. [PMID: 32916217 DOI: 10.1016/j.resmic.2020.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 10/23/2022]
Abstract
This study reports on the effect of inoculum history, growth substrates, and yeast extract on sodium chloride tolerance of Sulfobacillus thermosulfidooxidans DSM 9293T. The concentrations of NaCl for complete inhibition of Fe2+ oxidation by cells initially grown with ferrous iron sulfate, or tetrathionate, or pyrite as energy sources were 525 mM, 725 mM, and 800 mM, respectively. Noticeably, regardless of NaCl concentrations, oxygen consumption rates of S. thermosulfidooxidans with 20 mM tetrathionate were higher than with 50 mM FeSO4. NaCl concentrations of higher than 400 mM strongly inhibited the iron respiration of S. thermosulfidooxidans. In contrast, the presence of NaCl was shown to stimulate tetrathionate oxidation. This trend was especially pronounced in NaCl-adapted cells where respiration rates at 200 mM NaCl were threefold of those in the absence of NaCl. In NaCl-adapted cultures greater respiration rates for tetrathionate were observed than in non-NaCl-adapted cultures, especially at concentrations ≥ 200 mM NaCl. At concentrations of ≤ 200 mM NaCl, cell growth and iron oxidation were enhanced with the addition of increasing concentrations of yeast extract. Thus, cell numbers in cultures with 0.05% yeast extract were ∼5 times higher than without yeast extract addition. At NaCl concentration as high as 400 mM, however, iron oxidation rates improved compared to control assays without yeast extract, but there was no clear dependence on yeast extract concentrations. The initial growth of bacteria with and without yeast extract in the presence of different NaCl concentrations was shown to impact leaching of copper from chalcopyrite. Copper dissolution was enhanced in the presence of 200 mM NaCl and absence of yeast extract, while the addition of 0.02% yeast extract was shown to promote copper solubilization in the presence of 500 mM NaCl.
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Affiliation(s)
- Dieu Huynh
- Environmental Microbiology, Institute of Biosciences, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany.
| | - Stefan R Kaschabek
- Environmental Microbiology, Institute of Biosciences, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany.
| | - Michael Schlömann
- Environmental Microbiology, Institute of Biosciences, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany.
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19
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Huynh D, Norambuena J, Boldt C, Kaschabek SR, Levicán G, Schlömann M. Effect of Sodium Chloride on Pyrite Bioleaching and Initial Attachment by Sulfobacillus thermosulfidooxidans. Front Microbiol 2020; 11:2102. [PMID: 33013767 PMCID: PMC7516052 DOI: 10.3389/fmicb.2020.02102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/10/2020] [Indexed: 12/02/2022] Open
Abstract
Biomining applies microorganisms to extract valuable metals from usually sulfidic ores. However, acidophilic iron (Fe)-oxidizing bacteria tend to be sensitive to chloride ions which may be present in biomining operations. This study investigates the bioleaching of pyrite (FeS2), as well as the attachment to FeS2 by Sulfobacillus thermosulfidooxidans DSM 9293T in the presence of elevated sodium chloride (NaCl) concentrations. The bacteria were still able to oxidize iron in the presence of up to 0.6M NaCl (35 g/L), and the addition of NaCl in concentrations up to 0.2M (~12 g/L) did not inhibit iron oxidation and growth of S. thermosulfidooxidans in leaching cultures within the first 7 days. However, after approximately 7 days of incubation, ferrous iron (Fe2+) concentrations were gradually increased in leaching assays with NaCl, indicating that iron oxidation activity over time was reduced in those assays. Although the inhibition by 0.1M NaCl (~6 g/L) of bacterial growth and iron oxidation activity was not evident at the beginning of the experiment, over extended leaching duration NaCl was likely to have an inhibitory effect. Thus, after 36 days of the experiment, bioleaching of FeS2 with 0.1M NaCl was reduced significantly in comparison to control assays without NaCl. Pyrite dissolution decreased with the increase of NaCl. Nevertheless, pyrite bioleaching by S. thermosulfidooxidans was still possible at NaCl concentrations as high as 0.4M (~23 g/L NaCl). Besides, cell attachment in the presence of different concentrations of NaCl was investigated. Cells of S. thermosulfidooxidans attached heterogeneously on pyrite surfaces regardless of NaCl concentration. Noticeably, bacteria were able to adhere to pyrite surfaces in the presence of NaCl as high as 0.4M. Although NaCl addition inhibited iron oxidation activity and bioleaching of FeS2, the presence of 0.2M seemed to enhance bacterial attachment of S. thermosulfidooxidans on pyrite surfaces in comparison to attachment without NaCl.
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Affiliation(s)
- Dieu Huynh
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Javiera Norambuena
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Christin Boldt
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Stefan R. Kaschabek
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Gloria Levicán
- Biology Department, Universidad de Santiago de Chile, Santiago, Chile
| | - Michael Schlömann
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
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