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Biomineralization and biotechnological applications of bacterial magnetosomes. Colloids Surf B Biointerfaces 2022; 216:112556. [PMID: 35605573 DOI: 10.1016/j.colsurfb.2022.112556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/27/2022] [Accepted: 05/07/2022] [Indexed: 01/13/2023]
Abstract
Magnetosomes intracellularly biomineralized by Magnetotactic bacteria (MTB) are membrane-enveloped nanoparticles of the magnetic minerals magnetite (Fe3O4) or greigite (Fe3S4). MTB thrive in oxic-anoxic interface and exhibit magnetotaxis due to the presence of magnetosomes. Because of the unique characteristic and bionavigation inspiration of magnetosomes, MTB has been a subject of study focused on by biologists, medical pharmacologists, geologists, and physicists since the discovery. We herein first briefly review the features of MTB and magnetosomes. The recent insights into the process and mechanism for magnetosome biomineralization including iron uptake, magnetosome membrane invagination, iron mineralization and magnetosome chain assembly are summarized in detail. Additionally, the current research progress in biotechnological applications of magnetosomes is also elucidated, such as drug delivery, MRI image contrast, magnetic hyperthermia, wastewater treatment, and cell separation. This review would expand our understanding of biomineralization and biotechnological applications of bacterial magnetosomes.
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2
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Zhang WJ, Wu LF. Flagella and Swimming Behavior of Marine Magnetotactic Bacteria. Biomolecules 2020; 10:biom10030460. [PMID: 32188162 PMCID: PMC7175107 DOI: 10.3390/biom10030460] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/14/2020] [Accepted: 03/15/2020] [Indexed: 12/22/2022] Open
Abstract
Marine environments are generally characterized by low bulk concentrations of nutrients that are susceptible to steady or intermittent motion driven by currents and local turbulence. Marine bacteria have therefore developed strategies, such as very fast-swimming and the exploitation of multiple directional sensing–response systems in order to efficiently migrate towards favorable places in nutrient gradients. The magnetotactic bacteria (MTB) even utilize Earth’s magnetic field to facilitate downward swimming into the oxic–anoxic interface, which is the most favorable place for their persistence and proliferation, in chemically stratified sediments or water columns. To ensure the desired flagella-propelled motility, marine MTBs have evolved an exquisite flagellar apparatus, and an extremely high number (tens of thousands) of flagella can be found on a single entity, displaying a complex polar, axial, bounce, and photosensitive magnetotactic behavior. In this review, we describe gene clusters, the flagellar apparatus architecture, and the swimming behavior of marine unicellular and multicellular magnetotactic bacteria. The physiological significance and mechanisms that govern these motions are discussed.
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Affiliation(s)
- Wei-Jia Zhang
- Laboratory of Deep-Sea Microbial Cell Biology, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China;
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, F-13402 CNRS-Marseille, France/CAS-Sanya 572000, China
| | - Long-Fei Wu
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, F-13402 CNRS-Marseille, France/CAS-Sanya 572000, China
- Aix Marseille Univ, CNRS, LCB, IMM, IM2B, CENTURI, F-13402 Marseille, France
- Correspondence: ; Tel.: +33-4-9116-4157
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3
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Wang X, Zheng H, Wang Q, Jiang W, Wen Y, Tian J, Sun J, Li Y, Li J. Novel Protein Mg2046 Regulates Magnetosome Synthesis in Magnetospirillum gryphiswaldense MSR-1 by Modulating a Proper Redox Status. Front Microbiol 2019; 10:1478. [PMID: 31297108 PMCID: PMC6607277 DOI: 10.3389/fmicb.2019.01478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 06/13/2019] [Indexed: 11/13/2022] Open
Abstract
Magnetotactic bacteria (MTB) are a large, polyphyletic group of aquatic microorganisms capable of absorbing large amounts of iron and synthesizing intercellular nano-scaled nanoparticles termed magnetosomes. In our previous transcriptomic studies, we discovered that a novel gene (MGMSRv2_2046, termed as mg2046) in Magnetospirillum gryphiswaldense strain MSR-1 was significantly up-regulated during the period of magnetosome synthesis. In the present study, we constructed a MSR-1 mutant strain with deletion of mg2046 (termed Δmg2046) in order to evaluate the role of this gene in cell physiological status and magnetosome formation process. In comparison with wild-type MSR-1, Δmg2046 showed similar cell growth, but much lower cell magnetic response, smaller number and size of magnetosomes, and reduced iron absorption ability. mg2046 deletion evidently disrupted iron uptake, and redox equilibrium, and strongly inhibited transcription of dissimilatory denitrification pathway genes. Our experimental findings, taken together with results of gene homology analysis, indicate that Mg2046 acts as a positive regulator in MSR-1 under microaerobic conditions, responding to hypoxia signals and participating in regulation of oxygen metabolism, in part as a co-regulator of dissimilatory denitrification pathway with oxygen sensor MgFnr (MGMSRv2_2946, termed as Mg2946). Mg2046 is clearly involved in coupled regulation of cellular oxygen, iron and nitrogen metabolism under micro-aerobic or anaerobic conditions. Our findings help explain how MSR-1 cells initiate dissimilatory denitrification pathway and overcome energy deficiency under microaerobic conditions, and have broader implications regarding bacterial survival and energy metabolism strategies under hypoxia.
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Affiliation(s)
- Xu Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China.,Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Haolan Zheng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Qing Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Wei Jiang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Ying Wen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jiesheng Tian
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jianbo Sun
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Ying Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jilun Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
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4
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Bacterial community structure and novel species of magnetotactic bacteria in sediments from a seamount in the Mariana volcanic arc. Sci Rep 2017; 7:17964. [PMID: 29269894 PMCID: PMC5740136 DOI: 10.1038/s41598-017-17445-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 11/27/2017] [Indexed: 12/15/2022] Open
Abstract
Seamounts are undersea mountains rising abruptly from the sea floor and interacting dynamically with underwater currents. They represent unique biological habitats with various microbial community structures. Certain seamount bacteria form conspicuous extracellular iron oxide structures, including encrusted stalks, flattened bifurcating tubes, and filamentous sheaths. To extend our knowledge of seamount ecosystems, we performed an integrated study on population structure and the occurrence of magnetotactic bacteria (MTB) that synthesize intracellular iron oxide nanocrystals in sediments of a seamount in the Mariana volcanic arc. We found Proteobacteria dominant at 13 of 14 stations, but ranked second in abundance to members of the phylum Firmicutes at the deep-water station located on a steep slope facing the Mariana-Yap Trench. Live MTB dwell in biogenic sediments from all 14 stations ranging in depth from 238 to 2,023 m. Some magnetotactic cocci possess the most complex flagellar apparatus yet reported; 19 flagella are arranged in a 3:4:5:4:3 array within a flagellar bundle. Phylogenetic analysis of 16S rRNA gene sequences identified 16 novel species of MTB specific to this seamount. Together the results obtained indicate that geographic properties of the seamount stations are important in shaping the bacterial community structure and the MTB composition.
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5
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Wang Q, Wang X, Zhang W, Li X, Zhou Y, Li D, Wang Y, Tian J, Jiang W, Zhang Z, Peng Y, Wang L, Li Y, Li J. Physiological characteristics of Magnetospirillum gryphiswaldense MSR-1 that control cell growth under high-iron and low-oxygen conditions. Sci Rep 2017; 7:2800. [PMID: 28584275 PMCID: PMC5459824 DOI: 10.1038/s41598-017-03012-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/21/2017] [Indexed: 11/17/2022] Open
Abstract
Magnetosome formation by Magnetospirillum gryphiswaldense MSR-1 is dependent on iron and oxygen levels. We used transcriptome to evaluate transcriptional profiles of magnetic and non-magnetic MSR-1 cells cultured under high-iron and low-iron conditions. A total of 80 differentially expressed genes (DEGs) were identified, including 53 upregulated and 27 downregulated under high-iron condition. These DEGs belonged to the functional categories of biological regulation, oxidation-reduction process, and ion binding and transport, and were involved in sulfur metabolism and cysteine/methionine metabolism. Comparison with our previous results from transcriptome data under oxygen-controlled conditions indicated that transcription of mam or mms was not regulated by oxygen or iron signals. 17 common DEGs in iron- and oxygen-transcriptomes were involved in energy production, iron transport, and iron metabolism. Some unknown-function DEGs participate in iron transport and metabolism, and some are potential biomarkers for identification of Magnetospirillum strains. IrrA and IrrB regulate iron transport in response to low-oxygen and high-iron signals, respectively. Six transcription factors were predicted to regulate DEGs. Fur and Crp particularly co-regulate DEGs in response to changes in iron or oxygen levels, in a proposed joint regulatory network of DEGs. Our findings provide new insights into biomineralization processes under high- vs. low-iron conditions in magnetotactic bacteria.
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Affiliation(s)
- Qing Wang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Xu Wang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Weijia Zhang
- Institute of Deep-sea Science and Engineering, China Academy of Sciences, Sanya, 572000, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Xianyu Li
- Beijing Key Laboratory of Traditional Chinese Medicine Basic Research on Prevention and Treatment for Major Diseases, Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, 100700, P.R. China
| | - Yuan Zhou
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Dan Li
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Yinjia Wang
- Tianjin Biochip Corporation, Tianjin, 300457, P.R. China
| | - Jiesheng Tian
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Wei Jiang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Ziding Zhang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Youliang Peng
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Lei Wang
- Tianjin Biochip Corporation, Tianjin, 300457, P.R. China
| | - Ying Li
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China. .,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China.
| | - Jilun Li
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
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6
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Ji B, Zhang SD, Zhang WJ, Rouy Z, Alberto F, Santini CL, Mangenot S, Gagnot S, Philippe N, Pradel N, Zhang L, Tempel S, Li Y, Médigue C, Henrissat B, Coutinho PM, Barbe V, Talla E, Wu LF. The chimeric nature of the genomes of marine magnetotactic coccoid-ovoid bacteria defines a novel group of P
roteobacteria. Environ Microbiol 2017; 19:1103-1119. [DOI: 10.1111/1462-2920.13637] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 11/23/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Boyang Ji
- Aix Marseille Univ, CNRS, LCB; Marseille France
| | - Sheng-Da Zhang
- Aix Marseille Univ, CNRS, LCB; Marseille France
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
| | - Wei-Jia Zhang
- Aix Marseille Univ, CNRS, LCB; Marseille France
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
- State Key Laboratories for Agro-biotechnology and College of Biological Sciences; China Agricultural University; Beijing 100193 China
| | - Zoe Rouy
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Génomique-Génoscope; Laboratoire d'Analyse Bioinformatique en Génomique et Métabolisme; 2 rue Gaston Crémieux Evry F-91057 France
- Centre National de la Recherche Scientifique; Unité Mixte de Recherche 8030; 2 rue Gaston Crémieux Evry F-91057 France
- UEVE; Université d'Evry, Boulevard François Mitterrand; Evry F-91025 France
| | - François Alberto
- Aix Marseille Univ, CNRS, LCB; Marseille France
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
| | - Claire-Lise Santini
- Aix Marseille Univ, CNRS, LCB; Marseille France
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
| | - Sophie Mangenot
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Génomique-Génoscope; Laboratoire de Biologie Moléculaire pour l'Etude des Génomes; 2 rue Gaston Crémieux Evry cedex CP 5706 - 91057 France
| | | | | | - Nathalie Pradel
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
- Aix Marseille Univ, Univ Toulon, CNRS, IRD; Marseille France
| | | | | | - Ying Li
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
- State Key Laboratories for Agro-biotechnology and College of Biological Sciences; China Agricultural University; Beijing 100193 China
| | - Claudine Médigue
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Génomique-Génoscope; Laboratoire d'Analyse Bioinformatique en Génomique et Métabolisme; 2 rue Gaston Crémieux Evry F-91057 France
- Centre National de la Recherche Scientifique; Unité Mixte de Recherche 8030; 2 rue Gaston Crémieux Evry F-91057 France
- UEVE; Université d'Evry, Boulevard François Mitterrand; Evry F-91025 France
| | | | | | - Valérie Barbe
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Génomique-Génoscope; Laboratoire de Biologie Moléculaire pour l'Etude des Génomes; 2 rue Gaston Crémieux Evry cedex CP 5706 - 91057 France
| | | | - Long-Fei Wu
- Aix Marseille Univ, CNRS, LCB; Marseille France
- Centre National de la Recherche Scientifique; Laboratoire International Associé de la Bio-Minéralisation et Nano-Structures (LIA-BioMNSL); Marseille cedex 20 F-13402 France
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7
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Araujo ACV, Morillo V, Cypriano J, Teixeira LCRS, Leão P, Lyra S, Almeida LGD, Bazylinski DA, Ribeiro de Vasconcelos AT, Abreu F, Lins U. Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment. BMC Genomics 2016; 17:726. [PMID: 27801294 PMCID: PMC5088516 DOI: 10.1186/s12864-016-3064-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Magnetotactic bacteria (MTB) are a unique group of prokaryotes that have a potentially high impact on global geochemical cycling of significant primary elements because of their metabolic plasticity and the ability to biomineralize iron-rich magnetic particles called magnetosomes. Understanding the genetic composition of the few cultivated MTB along with the unique morphological features of this group of bacteria may provide an important framework for discerning their potential biogeochemical roles in natural environments. RESULTS Genomic and ultrastructural analyses were combined to characterize the cultivated magnetotactic coccus Magnetofaba australis strain IT-1. Cells of this species synthesize a single chain of elongated, cuboctahedral magnetite (Fe3O4) magnetosomes that cause them to align along magnetic field lines while they swim being propelled by two bundles of flagella at velocities up to 300 μm s-1. High-speed microscopy imaging showed the cells move in a straight line rather than in the helical trajectory described for other magnetotactic cocci. Specific genes within the genome of Mf. australis strain IT-1 suggest the strain is capable of nitrogen fixation, sulfur reduction and oxidation, synthesis of intracellular polyphosphate granules and transporting iron with low and high affinity. Mf. australis strain IT-1 and Magnetococcus marinus strain MC-1 are closely related phylogenetically although similarity values between their homologous proteins are not very high. CONCLUSION Mf. australis strain IT-1 inhabits a constantly changing environment and its complete genome sequence reveals a great metabolic plasticity to deal with these changes. Aside from its chemoautotrophic and chemoheterotrophic metabolism, genomic data indicate the cells are capable of nitrogen fixation, possess high and low affinity iron transporters, and might be capable of reducing and oxidizing a number of sulfur compounds. The relatively large number of genes encoding transporters as well as chemotaxis receptors in the genome of Mf. australis strain IT-1 combined with its rapid swimming velocities, indicate that cells respond rapidly to environmental changes.
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Affiliation(s)
- Ana Carolina Vieira Araujo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.,Current institution: Departamento de Biologia, Universidade Federal de São Carlos, 18052-780, Sorocaba, SP, Brazil
| | - Viviana Morillo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.,School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
| | - Jefferson Cypriano
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | | | - Pedro Leão
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Sidcley Lyra
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Luiz Gonzaga de Almeida
- Departamento de Matemática Aplicada e Computacional, Laboratório Nacional de Computação Científica, 25651-070, Petrópolis, RJ, Brazil
| | - Dennis A Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
| | - Ana Tereza Ribeiro de Vasconcelos
- Departamento de Matemática Aplicada e Computacional, Laboratório Nacional de Computação Científica, 25651-070, Petrópolis, RJ, Brazil
| | - Fernanda Abreu
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Ulysses Lins
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.
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8
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Zhang SD, Santini CL, Zhang WJ, Barbe V, Mangenot S, Guyomar C, Garel M, Chen HT, Li XG, Yin QJ, Zhao Y, Armengaud J, Gaillard JC, Martini S, Pradel N, Vidaud C, Alberto F, Médigue C, Tamburini C, Wu LF. Genomic and physiological analysis reveals versatile metabolic capacity of deep-sea Photobacterium phosphoreum ANT-2200. Extremophiles 2016; 20:301-10. [PMID: 27039108 DOI: 10.1007/s00792-016-0822-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/01/2016] [Indexed: 10/22/2022]
Abstract
Bacteria of the genus Photobacterium thrive worldwide in oceans and show substantial eco-physiological diversity including free-living, symbiotic and piezophilic life styles. Genomic characteristics underlying this variability across species are poorly understood. Here we carried out genomic and physiological analysis of Photobacterium phosphoreum strain ANT-2200, the first deep-sea luminous bacterium of which the genome has been sequenced. Using optical mapping we updated the genomic data and reassembled it into two chromosomes and a large plasmid. Genomic analysis revealed a versatile energy metabolic potential and physiological analysis confirmed its growth capacity by deriving energy from fermentation of glucose or maltose, by respiration with formate as electron donor and trimethlyamine N-oxide (TMAO), nitrate or fumarate as electron acceptors, or by chemo-organo-heterotrophic growth in rich media. Despite that it was isolated at a site with saturated dissolved oxygen, the ANT-2200 strain possesses four gene clusters coding for typical anaerobic enzymes, the TMAO reductases. Elevated hydrostatic pressure enhances the TMAO reductase activity, mainly due to the increase of isoenzyme TorA1. The high copy number of the TMAO reductase isoenzymes and pressure-enhanced activity might imply a strategy developed by bacteria to adapt to deep-sea habitats where the instant TMAO availability may increase with depth.
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Affiliation(s)
- Sheng-Da Zhang
- Deep-Sea Microbial Cell Biology, Department of Deep Sea Sciences, Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Claire-Lise Santini
- LCB UMR 7257, Aix-Marseille Université, CNRS, IMM, 31, Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Wei-Jia Zhang
- Deep-Sea Microbial Cell Biology, Department of Deep Sea Sciences, Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | | | | | - Charlotte Guyomar
- LCB UMR 7257, Aix-Marseille Université, CNRS, IMM, 31, Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Marc Garel
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, Mediterranean Institute of Oceanography (MIO), UM110, 13288, Marseille, France
| | - Hai-Tao Chen
- Deep-Sea Microbial Cell Biology, Department of Deep Sea Sciences, Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Xue-Gong Li
- Deep-Sea Microbial Cell Biology, Department of Deep Sea Sciences, Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Qun-Jian Yin
- Deep-Sea Microbial Cell Biology, Department of Deep Sea Sciences, Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Yuan Zhao
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | | | | | - Séverine Martini
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, Mediterranean Institute of Oceanography (MIO), UM110, 13288, Marseille, France
| | - Nathalie Pradel
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, Mediterranean Institute of Oceanography (MIO), UM110, 13288, Marseille, France
| | | | - François Alberto
- LCB UMR 7257, Aix-Marseille Université, CNRS, IMM, 31, Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China
| | - Claudine Médigue
- Laboratoire d'Analyse Bioinformatique en Génomique et Métabolisme, CEA/DSV/IG/Genoscope and CNRS-UMR 8030 and Univ. Evry Val d'Esssone, Evry, France
| | - Christian Tamburini
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, Mediterranean Institute of Oceanography (MIO), UM110, 13288, Marseille, France
| | - Long-Fei Wu
- LCB UMR 7257, Aix-Marseille Université, CNRS, IMM, 31, Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France. .,France-China Bio-Mineralization and Nano-Structure Laboratory (LIA-BioMNSL), LCB-CNRS, Marseille, France/SIDSSE-CAS, Sanya, China.
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9
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Janesch B, Schirmeister F, Maresch D, Altmann F, Messner P, Kolarich D, Schäffer C. Flagellin glycosylation in Paenibacillus alvei CCM 2051T. Glycobiology 2015; 26:74-87. [PMID: 26405108 DOI: 10.1093/glycob/cwv087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/21/2015] [Indexed: 12/21/2022] Open
Abstract
Flagellin glycosylation impacts, in several documented cases, the functionality of bacterial flagella. The basis of flagellin glycosylation has been studied for various Gram-negative bacteria, but less is known about flagellin glycans of Gram-positive bacteria including Paenibacillus alvei, a secondary invader of honeybee colonies diseased with European foulbrood. Paenibacillus alvei CCM 2051(T) swarms vigorously on solidified culture medium, with swarming relying on functional flagella as evidenced by abolished biofilm formation of a non-motile P. alvei mutant defective in the flagellin protein Hag. Here, the glycobiology of the polar P. alvei flagella was investigated. Analysis on purified flagellin demonstrated that the 30-kDa Hag protein (PAV_2c01710) is modified with an O-linked trisaccharide comprised of one hexose and two N-acetyl-hexosamine residues, at three sites of glycosylation. Downstream of the hag gene on the bacterial chromosome, two open reading frames (PAV_2c01630, PAV_2c01640) encoding putative glycosyltransferases were shown to constitute a flagellin glycosylation island. Mutants defective in these genes exhibited altered migration in sodium dodecyl sulfate polyacrylamide gel electrophoresis as well as loss of extracellular flagella production and bacterial motility. This study reveals that flagellin glycosylation in P. alvei is pivotal to flagella formation and bacterial motility in vivo, and simultaneously identifies flagella glycosylation as a second protein O-glycosylation system in this bacterium, in addition to the well-investigated S-layer tyrosine O-glycosylation pathway.
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Affiliation(s)
- Bettina Janesch
- Department of NanoBiotechnology, NanoGlycobiology Unit, Universität für Bodenkultur Wien, Muthgasse 11, Vienna A-1190, Austria
| | - Falko Schirmeister
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam 14424, Germany Institute of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, Berlin 14195, Germany
| | - Daniel Maresch
- Department of Chemistry, Division of Biochemistry, Universität für Bodenkultur Wien, Muthgasse 18, Vienna A-1190, Austria
| | - Friedrich Altmann
- Department of Chemistry, Division of Biochemistry, Universität für Bodenkultur Wien, Muthgasse 18, Vienna A-1190, Austria
| | - Paul Messner
- Department of NanoBiotechnology, NanoGlycobiology Unit, Universität für Bodenkultur Wien, Muthgasse 11, Vienna A-1190, Austria
| | - Daniel Kolarich
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam 14424, Germany
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology Unit, Universität für Bodenkultur Wien, Muthgasse 11, Vienna A-1190, Austria
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10
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Iron response regulator protein IrrB in Magnetospirillum gryphiswaldense MSR-1 helps control the iron/oxygen balance, oxidative stress tolerance, and magnetosome formation. Appl Environ Microbiol 2015; 81:8044-53. [PMID: 26386052 DOI: 10.1128/aem.02585-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 08/31/2015] [Indexed: 01/15/2023] Open
Abstract
Magnetotactic bacteria are capable of forming nanosized, membrane-enclosed magnetosomes under iron-rich and oxygen-limited conditions. The complete genomic sequence of Magnetospirillum gryphiswaldense strain MSR-1 has been analyzed and found to contain five fur homologue genes whose protein products are predicted to be involved in iron homeostasis and the response to oxidative stress. Of these, only the MGMSRv2_3149 gene (irrB) was significantly downregulated under high-iron and low-oxygen conditions, during the transition of cell growth from the logarithmic to the stationary phase. The encoded protein, IrrB, containing the conserved HHH motif, was identified as an iron response regulator (Irr) protein belonging to the Fur superfamily. To investigate the function of IrrB, we constructed an irrB deletion mutant (ΔirrB). The levels of cell growth and magnetosome formation were lower in the ΔirrB strain than in the wild type (WT) under both high-iron and low-iron conditions. The ΔirrB strain also showed lower levels of iron uptake and H2O2 tolerance than the WT. Quantitative real-time reverse transcription-PCR analysis indicated that the irrB mutation reduced the expression of numerous genes involved in iron transport, iron storage, heme biosynthesis, and Fe-S cluster assembly. Transcription studies of the other fur homologue genes in the ΔirrB strain indicated complementary functions of the Fur proteins in MSR-1. IrrB appears to be directly responsible for iron metabolism and homeostasis and to be indirectly involved in magnetosome formation. We propose two IrrB-regulated networks (under high- and low-iron conditions) in MSR-1 cells that control the balance of iron and oxygen metabolism and account for the coexistence of five Fur homologues.
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11
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Salt Stress Induced Changes in the Exoproteome of the Halotolerant Bacterium Tistlia consotensis Deciphered by Proteogenomics. PLoS One 2015; 10:e0135065. [PMID: 26287734 PMCID: PMC4545795 DOI: 10.1371/journal.pone.0135065] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 07/16/2015] [Indexed: 11/19/2022] Open
Abstract
The ability of bacteria to adapt to external osmotic changes is fundamental for their survival. Halotolerant microorganisms, such as Tistlia consotensis, have to cope with continuous fluctuations in the salinity of their natural environments which require effective adaptation strategies against salt stress. Changes of extracellular protein profiles from Tistlia consotensis in conditions of low and high salinities were monitored by proteogenomics using a bacterial draft genome. At low salinity, we detected greater amounts of the HpnM protein which is involved in the biosynthesis of hopanoids. This may represent a novel, and previously unreported, strategy by halotolerant microorganisms to prevent the entry of water into the cell under conditions of low salinity. At high salinity, proteins associated with osmosensing, exclusion of Na+ and transport of compatible solutes, such as glycine betaine or proline are abundant. We also found that, probably in response to the high salt concentration, T. consotensis activated the synthesis of flagella and triggered a chemotactic response neither of which were observed at the salt concentration which is optimal for growth. Our study demonstrates that the exoproteome is an appropriate indicator of adaptive response of T. consotensis to changes in salinity because it allowed the identification of key proteins within its osmoadaptive mechanism that had not previously been detected in its cell proteome.
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12
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Opposite and Coordinated Rotation of Amphitrichous Flagella Governs Oriented Swimming and Reversals in a Magnetotactic Spirillum. J Bacteriol 2015; 197:3275-82. [PMID: 26240070 DOI: 10.1128/jb.00172-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 07/30/2015] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Current knowledge regarding the mechanism that governs flagellar motor rotation in response to environmental stimuli stems mainly from the study of monotrichous and peritrichous bacteria. Little is known about how two polar flagella, one at each cell pole of the so-called amphitrichous bacterium, are coordinated to steer the swimming. Here we fluorescently labeled the flagella of Magnetospirillum magneticum AMB-1 cells and took advantage of the magnetically controllable swimming of this bacterium to investigate flagellar rotation in moving cells. We identified three motility behaviors (runs, tumbles, and reversals) and two characteristic fluorescence patterns likely corresponding to flagella rotating in opposite directions. Each AMB-1 locomotion mode was systematically associated with particular flagellar patterns at the poles which led us to conclude that, while cell runs are allowed by the asymmetrical rotation of flagellar motors, their symmetrical rotation triggers cell tumbling. Our observations point toward a precise coordination of the two flagellar motors which can be temporarily unsynchronized during tumbling. IMPORTANCE Motility is essential for bacteria to search for optimal niches and survive. Many bacteria use one or several flagella to explore their environment. The mechanism by which bipolarly flagellated cells coordinate flagellar rotation is poorly understood. We took advantage of the genetic amenability and magnetically controlled swimming of the spirillum-shaped magnetotactic bacterium Magnetospirillum magneticum AMB-1 to correlate cell motion with flagellar rotation. We found that asymmetric rotation of the flagella (counterclockwise at the lagging pole and clockwise at the leading pole) enables cell runs whereas symmetric rotation triggers cell tumbling. Taking into consideration similar observations in spirochetes, bacteria possessing bipolar ribbons of periplasmic flagella, we propose a conserved motility paradigm for spirillum-shaped bipolarly flagellated bacteria.
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13
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Deng Z, Wang Q, Liu Z, Zhang M, Machado ACD, Chiu TP, Feng C, Zhang Q, Yu L, Qi L, Zheng J, Wang X, Huo X, Qi X, Li X, Wu W, Rohs R, Li Y, Chen Z. Mechanistic insights into metal ion activation and operator recognition by the ferric uptake regulator. Nat Commun 2015; 6:7642. [PMID: 26134419 PMCID: PMC4506495 DOI: 10.1038/ncomms8642] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 05/27/2015] [Indexed: 01/21/2023] Open
Abstract
Ferric uptake regulator (Fur) plays a key role in the iron homeostasis of prokaryotes, such as bacterial pathogens, but the molecular mechanisms and structural basis of Fur-DNA binding remain incompletely understood. Here, we report high-resolution structures of Magnetospirillum gryphiswaldense MSR-1 Fur in four different states: apo-Fur, holo-Fur, the Fur-feoAB1 operator complex and the Fur-Pseudomonas aeruginosa Fur box complex. Apo-Fur is a transition metal ion-independent dimer whose binding induces profound conformational changes and confers DNA-binding ability. Structural characterization, mutagenesis, biochemistry and in vivo data reveal that Fur recognizes DNA by using a combination of base readout through direct contacts in the major groove and shape readout through recognition of the minor-groove electrostatic potential by lysine. The resulting conformational plasticity enables Fur binding to diverse substrates. Our results provide insights into metal ion activation and substrate recognition by Fur that suggest pathways to engineer magnetotactic bacteria and antipathogenic drugs.
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Affiliation(s)
- Zengqin Deng
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Qing Wang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Zhao Liu
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Manfeng Zhang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Ana Carolina Dantas Machado
- Molecular and Computational Biology Program, Departments of Biological Sciences, Chemistry, Physics, and Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Tsu-Pei Chiu
- Molecular and Computational Biology Program, Departments of Biological Sciences, Chemistry, Physics, and Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Chong Feng
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Qi Zhang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Lin Yu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Lei Qi
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Jiangge Zheng
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Xu Wang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - XinMei Huo
- Institute of Apicultural Research, Key Laboratory of Pollinating Insect Biology, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Xiaoxuan Qi
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Xiaorong Li
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Wei Wu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Remo Rohs
- Molecular and Computational Biology Program, Departments of Biological Sciences, Chemistry, Physics, and Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Ying Li
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
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14
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Périamé M, Pagès JM, Davin-Regli A. Enterobacter gergoviae
membrane modifications are involved in the adaptive response to preservatives used in cosmetic industry. J Appl Microbiol 2014; 118:49-61. [DOI: 10.1111/jam.12676] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/14/2014] [Accepted: 10/24/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Marina Périamé
- UMR-MD-1, Aix-Marseille Université; IRBA, Transporteurs Membranaires; Chimiorésistance et Drug Design; Marseille France
| | - Jean-Marie Pagès
- UMR-MD-1, Aix-Marseille Université; IRBA, Transporteurs Membranaires; Chimiorésistance et Drug Design; Marseille France
| | - Anne Davin-Regli
- UMR-MD-1, Aix-Marseille Université; IRBA, Transporteurs Membranaires; Chimiorésistance et Drug Design; Marseille France
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15
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Construction of a microrobot system using magnetotactic bacteria for the separation of Staphylococcus aureus. Biomed Microdevices 2014; 16:761-70. [DOI: 10.1007/s10544-014-9880-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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16
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Abstract
Magnetotactic bacteria (MTB) are widespread, motile, diverse prokaryotes that biomineralize a unique organelle called the magnetosome. Magnetosomes consist of a nano-sized crystal of a magnetic iron mineral that is enveloped by a lipid bilayer membrane. In cells of almost all MTB, magnetosomes are organized as a well-ordered chain. The magnetosome chain causes the cell to behave like a motile, miniature compass needle where the cell aligns and swims parallel to magnetic field lines. MTB are found in almost all types of aquatic environments, where they can account for an important part of the bacterial biomass. The genes responsible for magnetosome biomineralization are organized as clusters in the genomes of MTB, in some as a magnetosome genomic island. The functions of a number of magnetosome genes and their associated proteins in magnetosome synthesis and construction of the magnetosome chain have now been elucidated. The origin of magnetotaxis appears to be monophyletic; that is, it developed in a common ancestor to all MTB, although horizontal gene transfer of magnetosome genes also appears to play a role in their distribution. The purpose of this review, based on recent progress in this field, is focused on the diversity and the ecology of the MTB and also the evolution and transfer of the molecular determinants involved in magnetosome formation.
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17
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Zhang SD, Petersen N, Zhang WJ, Cargou S, Ruan J, Murat D, Santini CL, Song T, Kato T, Notareschi P, Li Y, Namba K, Gué AM, Wu LF. Swimming behaviour and magnetotaxis function of the marine bacterium strain MO-1. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:14-20. [PMID: 24596258 DOI: 10.1111/1758-2229.12102] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 08/13/2013] [Accepted: 08/15/2013] [Indexed: 06/03/2023]
Abstract
Magnetotactic bacteria (MTB) have the unique capacity to align and swim along the geomagnetic field lines downward to the oxic-anoxic interface in chemically stratified water columns and sediments. They are most abundant within the first few centimetres of sediments below the water-sediment interface. It is unknown how MTB penetrate into the sediment layer and swim in the pocket water, while their movements are restricted by the alignment along the magnetic field lines. Here we characterized the swimming behaviour of the marine fast-swimming magnetotactic ovoid bacterium MO-1.We found that it rotates around and translates along its short body axis to the magnetic north (northward). MO-1 cells swim forward constantly for a minimum of 1770 μm without apparent stopping. When encountering obstacles, MO-1 cells squeeze through or swim southward to circumvent the obstacles. The distance of southward swimming is short and inversely proportional to the magnetic field strength. Using a magnetic shielding device, we provide direct evidence that magnetotaxis is beneficial to MO-1 growth and becomes essential at low cell density. Environmental implications of the fast-swimming magnetotactic behaviour of magnetococci are discussed.
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Affiliation(s)
- Sheng-Da Zhang
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS, UMR7283, Aix-Marseille Université, Marseille Cedex 20, F-13402, France; Laboratoire International Associé de la Biominéralisation et Nanostructure, CNRS-Marseille, Marseille, F-13402, France
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18
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Wang Q, Liu JX, Zhang WJ, Zhang TW, Yang J, Li Y. Expression patterns of key iron and oxygen metabolism genes during magnetosome formation in Magnetospirillum gryphiswaldense MSR-1. FEMS Microbiol Lett 2013; 347:163-72. [PMID: 23937222 DOI: 10.1111/1574-6968.12234] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 11/28/2022] Open
Abstract
To evaluate the expression patterns of genes involved in iron and oxygen metabolism during magnetosome formation, the profiles of 13 key genes in Magnetospirillum gryphiswaldense MSR-1 cells cultured under high-iron vs. low-iron conditions were examined. Cell growth rates did not differ between the two conditions. Only the high-iron cells produced magnetosomes. Transmission electron microscopy observations revealed that magnetosome formation began at 6 h and crystal maturation occurred from 10 to 18 h. Real-time polymerase chain reaction analysis showed that expression of these genes increased during cell growth and magnetosome synthesis, particularly for ferric reductase gene (fer6) and ferrous transport system-related genes feoAB1, feoAB2, sodB, and katG. The low-iron cells showed increased expression of feoAB1 and feoB2 from 12 to 18 h but no clear expression changes for the other genes. Expression patterns of the genes were divided by hierarchical clustering into four clusters for the high-iron cells and three clusters for the low-iron cells. Each cluster included both iron and oxygen metabolism genes showing similar expression patterns. The findings indicate the coordination and co-dependence of iron and oxygen metabolism gene activity to achieve a balance during the biomineralization process. Future transcriptome analysis will help elucidate the mechanism of biomineralization in MSR-1 magnetosome formation.
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Affiliation(s)
- Qing Wang
- State Key Laboratories for Agro-biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China; France-China Bio-mineralization and Nano-structure Laboratory, Beijing, China
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Architecture of a flagellar apparatus in the fast-swimming magnetotactic bacterium MO-1. Proc Natl Acad Sci U S A 2012. [PMID: 23184985 DOI: 10.1073/pnas.1215274109] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The bacterial flagellum is a motility organelle that consists of a rotary motor and a helical propeller. The flagella usually work individually or by forming a loose bundle to produce thrust. However, the flagellar apparatus of marine bacterium MO-1 is a tight bundle of seven flagellar filaments enveloped in a sheath, and it has been a mystery as to how the flagella rotate smoothly in coordination. Here we have used electron cryotomography to visualize the 3D architecture of the sheathed flagella. The seven filaments are enveloped with 24 fibrils in the sheath, and their basal bodies are arranged in an intertwined hexagonal array similar to the thick and thin filaments of vertebrate skeletal muscles. This complex and exquisite architecture strongly suggests that the fibrils counter-rotate between flagella in direct contact to minimize the friction of high-speed rotation of individual flagella in the tight bundle within the sheath to enable MO-1 cells to swim at about 300 µm/s.
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Two genera of magnetococci with bean-like morphology from intertidal sediments of the Yellow Sea, China. Appl Environ Microbiol 2012; 78:5606-11. [PMID: 22660708 DOI: 10.1128/aem.00081-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Magnetotactic bacteria have the unique capacity of being able to swim along geomagnetic field lines. They are Gram-negative bacteria with diverse morphologies and variable phylogenetic relatedness. Here, we describe a group of uncultivated marine magnetococci collected from intertidal sediments of Huiquan Bay in the Yellow Sea. They were coccoid-ovoid in morphology, with an average size of 2.8 ± 0.3 μm by 2.0 ± 0.2 μm. Differential interference contrast microscopy, fluorescence microscopy, and transmission electron microscopy revealed that each cell was apparently composed of two hemispheres. The cells synthesized iron oxide-type magnetosomes that clustered on one side of the cell at the interface between the two hemispheres. In some cells two chains of magnetosomes were observed across the interface. Each cell had two bundles of flagella enveloped in a sheath and displayed north-seeking helical motion. Two 16S rRNA gene sequences having 91.8% identity were obtained, and their authenticity was confirmed by fluorescence in situ hybridization. Phylogenetic analysis revealed that the magnetococci are affiliated with the Alphaproteobacteria and are most closely related to two uncultured magnetococci with sequence identities of 92.7% and 92.4%, respectively. Because they display a >7% sequence divergence to all bacteria reported, the bean-like magnetococci may represent two novel genera.
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