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A Cristae-Like Microcompartment in Desulfobacterota. mBio 2022; 13:e0161322. [PMID: 36321837 PMCID: PMC9764997 DOI: 10.1128/mbio.01613-22] [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] [Indexed: 01/25/2023] Open
Abstract
Some Alphaproteobacteria contain intracytoplasmic membranes (ICMs) and proteins homologous to those responsible for the mitochondrial cristae, an observation which has given rise to the hypothesis that the Alphaproteobacteria endosymbiont had already evolved cristae-like structures and functions. However, our knowledge of microbial fine structure is still limited, leaving open the possibility of structurally homologous ICMs outside the Alphaproteobacteria. Here, we report on the detailed characterization of lamellar cristae-like ICMs in environmental sulfate-reducing Desulfobacterota that form syntrophic partnerships with anaerobic methane-oxidizing (ANME) archaea. These structures are junction-bound to the cytoplasmic membrane and resemble the form seen in the lamellar cristae of opisthokont mitochondria. Extending these observations, we also characterized similar structures in Desulfovibrio carbinolicus, a close relative of the magnetotactic D. magneticus, which does not contain magnetosomes. Despite a remarkable structural similarity, the key proteins involved in cristae formation have not yet been identified in Desulfobacterota, suggesting that an analogous, but not a homologous, protein organization system developed during the evolution of some members of Desulfobacterota. IMPORTANCE Working with anaerobic consortia of methane oxidizing ANME archaea and their sulfate-reducing bacterial partners recovered from deep sea sediments and with the related sulfate-reducing bacterial isolate D. carbinolicus, we discovered that their intracytoplasmic membranes (ICMs) appear remarkably similar to lamellar cristae. Three-dimensional electron microscopy allowed for the novel analysis of the nanoscale attachment of ICMs to the cytoplasmic membrane, and these ICMs are structurally nearly identical to the crista junction architecture seen in metazoan mitochondria. However, the core junction-forming proteins must be different. The outer membrane vesicles were observed to bud from syntrophic Desulfobacterota, and darkly stained granules were prominent in both Desulfobacterota and D. carbinolicus. These findings expand the taxonomic breadth of ICM-producing microorganisms and add to our understanding of three-dimensional microbial fine structure in environmental microorganisms.
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Abstract
Magnetotactic bacteria (MTB) belong to several phyla. This class of microorganisms exhibits the ability of magneto-aerotaxis. MTB synthesize biominerals in organelle-like structures called magnetosomes, which contain single-domain crystals of magnetite (Fe3O4) or greigite (Fe3S4) characterized by a high degree of structural and compositional perfection. Magnetosomes from dead MTB could be preserved in sediments (called fossil magnetosomes or magnetofossils). Under certain conditions, magnetofossils are capable of retaining their remanence for millions of years. This accounts for the growing interest in MTB and magnetofossils in paleo- and rock magnetism and in a wider field of biogeoscience. At the same time, high biocompatibility of magnetosomes makes possible their potential use in biomedical applications, including magnetic resonance imaging, hyperthermia, magnetically guided drug delivery, and immunomagnetic analysis. In this review, we attempt to summarize the current state of the art in the field of MTB research and applications.
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Single- or double-membrane-bound vesicles and P, Ca, and Fe-containing granules in Xanthomonas citri cultured on a solid medium. Micron 2021; 143:103024. [PMID: 33549851 DOI: 10.1016/j.micron.2021.103024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 11/21/2022]
Abstract
The organelle-like structures of Xanthomonas citri, a bacterial pathogen that causes citrus canker, were investigated using an analytical transmission electron microscope. After high-pressure freezing, the bacteria were then freeze-substituted for imaging and element analysis. Miniscule electron-dense structures of varying shapes without a membrane enclosure were frequently observed near the cell poles in a 3-day culture. The bacteria formed cytoplasmic electron-dense spherical structures measuring approximately 50 nm in diameter. Furthermore, X. citri produced electron-dense or translucent ellipsoidal intracellular or extracellular granules. Single- or double-membrane-bound vesicles, including outer-inner membrane vesicles, were observed both inside and outside the cells. Most cells had been lysed in the 3-week X. citri culture, but they harbored one or two electron-dense spherical structures. Contrast-inverted scanning transmission electron microscopy images revealed distinct white spherical structures within the cytoplasm of X. citri. Likewise, energy-dispersive X-ray spectrometry showed the spatial heterogeneity and co-localization of phosphorus, oxygen, calcium, and iron only in the cytoplasmic electron-dense spherical structures, thus corroborating the nature of polyphosphate granules.
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Correa T, Bazylinski DA, Garcia F, Abreu F. A rapid and simple preparation of amphotericin B-loaded bacterial magnetite nanoparticles. RSC Adv 2021; 11:28000-28007. [PMID: 35480720 PMCID: PMC9038061 DOI: 10.1039/d1ra03950d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/10/2021] [Indexed: 11/21/2022] Open
Abstract
Three-dimensional representation of amphotericin B molecules bound to magnetosomes derived from Magnetovibrio blakemorei strain MV-1T. Drug molecules are electrostatically adsorbed onto nanoparticles coated with positively charged poly-l-lysine.
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Affiliation(s)
- Tarcisio Correa
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, UFRJ, Rio de Janeiro, RJ 21941-902, Brazil
| | - Dennis A. Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, Nevada, USA
| | - Flávio Garcia
- Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda Abreu
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, UFRJ, Rio de Janeiro, RJ 21941-902, Brazil
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5
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6
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Blondeau M, Sachse M, Boulogne C, Gillet C, Guigner JM, Skouri-Panet F, Poinsot M, Ferard C, Miot J, Benzerara K. Amorphous Calcium Carbonate Granules Form Within an Intracellular Compartment in Calcifying Cyanobacteria. Front Microbiol 2018; 9:1768. [PMID: 30127775 PMCID: PMC6087745 DOI: 10.3389/fmicb.2018.01768] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/16/2018] [Indexed: 12/17/2022] Open
Abstract
The recent discovery of cyanobacteria forming intracellular amorphous calcium carbonate (ACC) has challenged the former paradigm suggesting that cyanobacteria-mediated carbonatogenesis was exclusively extracellular. Yet, the mechanisms of intracellular biomineralization in cyanobacteria and in particular whether this takes place within an intracellular microcompartment, remain poorly understood. Here, we analyzed six cyanobacterial strains forming intracellular ACC by transmission electron microscopy. We tested two different approaches to preserve as well as possible the intracellular ACC inclusions: (i) freeze-substitution followed by epoxy embedding and room-temperature ultramicrotomy and (ii) high-pressure freezing followed by cryo-ultramicrotomy, usually referred to as cryo-electron microscopy of vitreous sections (CEMOVIS). We observed that the first method preserved ACC well in 500-nm-thick sections but not in 70-nm-thick sections. However, cell ultrastructures were difficult to clearly observe in the 500-nm-thick sections. In contrast, CEMOVIS provided a high preservation quality of bacterial ultrastructures, including the intracellular ACC inclusions in 50-nm-thick sections. ACC inclusions displayed different textures, suggesting varying brittleness, possibly resulting from different hydration levels. Moreover, an electron dense envelope of ∼2.5 nm was systematically observed around ACC granules in all studied cyanobacterial strains. This envelope may be composed of a protein shell or a lipid monolayer, but not a lipid bilayer as usually observed in other bacteria forming intracellular minerals. Overall, this study evidenced that ACC inclusions formed and were stabilized within a previously unidentified bacterial microcompartment in some species of cyanobacteria.
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Affiliation(s)
- Marine Blondeau
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Martin Sachse
- Unité Technologie et Service BioImagerie Ultrastructurale, Citech, Institut Pasteur, Paris, France
| | - Claire Boulogne
- CEA, Centre National de la Recherche Scientifique, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Cynthia Gillet
- CEA, Centre National de la Recherche Scientifique, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Jean-Michel Guigner
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Fériel Skouri-Panet
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Mélanie Poinsot
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Céline Ferard
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Jennyfer Miot
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Karim Benzerara
- UMR CNRS 7590, IRD, Muséum National d'Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
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7
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Cyrklaff M, Frischknecht F, Kudryashev M. Functional insights into pathogen biology from 3D electron microscopy. FEMS Microbiol Rev 2018; 41:828-853. [PMID: 28962014 DOI: 10.1093/femsre/fux041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/25/2017] [Indexed: 01/10/2023] Open
Abstract
In recent years, novel imaging approaches revolutionised our understanding of the cellular and molecular biology of microorganisms. These include advances in fluorescent probes, dynamic live cell imaging, superresolution light and electron microscopy. Currently, a major transition in the experimental approach shifts electron microscopy studies from a complementary technique to a method of choice for structural and functional analysis. Here we review functional insights into the molecular architecture of viruses, bacteria and parasites as well as interactions with their respective host cells gained from studies using cryogenic electron tomography and related methodologies.
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Affiliation(s)
- Marek Cyrklaff
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Mikhail Kudryashev
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt, Max-von-Laue Strasse 17, 60438 Frankfurt, Germany
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8
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Werckmann J, Cypriano J, Lefèvre CT, Dembelé K, Ersen O, Bazylinski DA, Lins U, Farina M. Localized iron accumulation precedes nucleation and growth of magnetite crystals in magnetotactic bacteria. Sci Rep 2017; 7:8291. [PMID: 28811607 PMCID: PMC5557804 DOI: 10.1038/s41598-017-08994-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/14/2017] [Indexed: 12/16/2022] Open
Abstract
Many magnetotactic bacteria (MTB) biomineralize magnetite crystals that nucleate and grow inside intracellular membranous vesicles that originate from invaginations of the cytoplasmic membrane. The crystals together with their surrounding membranes are referred to magnetosomes. Magnetosome magnetite crystals nucleate and grow using iron transported inside the vesicle by specific proteins. Here we address the question: can iron transported inside MTB for the production of magnetite crystals be spatially mapped using electron microscopy? Cultured and uncultured MTB from brackish and freshwater lagoons were studied using analytical transmission electron microscopy in an attempt to answer this question. Scanning transmission electron microscopy was used at sub-nanometric resolution to determine the distribution of elements by implementing high sensitivity energy dispersive X-ray (EDS) mapping and electron energy loss spectroscopy (EELS). EDS mapping showed that magnetosomes are enmeshed in a magnetosomal matrix in which iron accumulates close to the magnetosome forming a continuous layer visually appearing as a corona. EELS, obtained at high spatial resolution, confirmed that iron was present close to and inside the lipid bilayer magnetosome membrane. This study provides important clues to magnetite formation in MTB through the discovery of a mechanism where iron ions accumulate prior to magnetite biomineralization.
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Affiliation(s)
- Jacques Werckmann
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil.
| | - Jefferson Cypriano
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil
| | - Christopher T Lefèvre
- CNRS/CEA/Aix-Marseille Université, UMR7265 Institut de biosciences et biotechnologies, Laboratoire de Bioénergétique Cellulaire, 13108, Saint Paul lez Durance, France
| | - Kassiogé Dembelé
- Institut de physique et chimie des matériaux de Strasbourg (IPCMS) UMR 7504 CNRS 23 rue du Lœss, BP 43 67034, Strasbourg Cedex 2, France
| | - Ovidiu Ersen
- Institut de physique et chimie des matériaux de Strasbourg (IPCMS) UMR 7504 CNRS 23 rue du Lœss, BP 43 67034, Strasbourg Cedex 2, France
| | - Dennis A Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, Nevada, 89154-4004, USA
| | - Ulysses Lins
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil
| | - Marcos Farina
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil
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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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10
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Genetic and Ultrastructural Analysis Reveals the Key Players and Initial Steps of Bacterial Magnetosome Membrane Biogenesis. PLoS Genet 2016; 12:e1006101. [PMID: 27286560 PMCID: PMC4902198 DOI: 10.1371/journal.pgen.1006101] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/12/2016] [Indexed: 11/19/2022] Open
Abstract
Magnetosomes of magnetotactic bacteria contain well-ordered nanocrystals for magnetic navigation and have recently emerged as the most sophisticated model system to study the formation of membrane bounded organelles in prokaryotes. Magnetosome biosynthesis is thought to begin with the formation of a dedicated compartment, the magnetosome membrane (MM), in which the biosynthesis of a magnetic mineral is strictly controlled. While the biomineralization of magnetosomes and their subsequent assembly into linear chains recently have become increasingly well studied, the molecular mechanisms and early stages involved in MM formation remained poorly understood. In the Alphaproteobacterium Magnetospirillum gryphiswaldense, approximately 30 genes were found to control magnetosome biosynthesis. By cryo-electron tomography of several key mutant strains we identified the gene complement controlling MM formation in this model organism. Whereas the putative magnetosomal iron transporter MamB was most crucial for the process and caused the most severe MM phenotype upon elimination, MamM, MamQ and MamL were also required for the formation of wild-type-like MMs. A subset of seven genes (mamLQBIEMO) combined within a synthetic operon was sufficient to restore the formation of intracellular membranes in the absence of other genes from the key mamAB operon. Tracking of de novo magnetosome membrane formation by genetic induction revealed that magnetosomes originate from unspecific cytoplasmic membrane locations before alignment into coherent chains. Our results indicate that no single factor alone is essential for MM formation, which instead is orchestrated by the cumulative action of several magnetosome proteins. One of the most intriguing examples for membrane-bounded prokaryotic organelles are magnetosomes which consist of well-ordered chains of perfectly shaped magnetic nanocrystals that in many aquatic bacteria serve as geomagnetic field sensors to direct their swimming towards microoxic zones at the bottom of natural waters. In the model bacterium Magnetospirillum gryphiswaldense and related magnetotactic microorganisms, magnetosomes are formed by a complex pathway that is orchestrated by more than 30 genes. However, the initial and most crucial step of magnetosome biosynthesis, formation and differentiation of a dedicated intracellular membrane compartment for controlled biomineralization of magnetite crystals, remained only poorly understood. By ultrastructural analysis of several mutants and genetic induction of de novo magnetosome synthesis, we identified the key determinants and early steps of magnetosome membrane biogenesis. Our results suggest that formation of intracellular membranes in bacteria is mediated by a cumulative action of several factors, but apparently is differently controlled than intracellular membrane remodeling in eukaryotic cells.
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Oikonomou CM, Chang YW, Jensen GJ. A new view into prokaryotic cell biology from electron cryotomography. Nat Rev Microbiol 2016; 14:205-20. [PMID: 26923112 PMCID: PMC5551487 DOI: 10.1038/nrmicro.2016.7] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electron cryotomography (ECT) enables intact cells to be visualized in 3D in an essentially native state to 'macromolecular' (∼4 nm) resolution, revealing the basic architectures of complete nanomachines and their arrangements in situ. Since its inception, ECT has advanced our understanding of many aspects of prokaryotic cell biology, from morphogenesis to subcellular compartmentalization and from metabolism to complex interspecies interactions. In this Review, we highlight how ECT has provided structural and mechanistic insights into the physiology of bacteria and archaea and discuss prospects for the future.
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Affiliation(s)
- Catherine M Oikonomou
- Howard Hughes Medical Institute; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA
| | - Yi-Wei Chang
- Howard Hughes Medical Institute; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA
| | - Grant J Jensen
- Howard Hughes Medical Institute; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA
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12
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Li J, Menguy N, Gatel C, Boureau V, Snoeck E, Patriarche G, Leroy E, Pan Y. Crystal growth of bullet-shaped magnetite in magnetotactic bacteria of the Nitrospirae phylum. J R Soc Interface 2015; 12:rsif.2014.1288. [PMID: 25566884 DOI: 10.1098/rsif.2014.1288] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Magnetotactic bacteria (MTB) are known to produce single-domain magnetite or greigite crystals within intracellular membrane organelles and to navigate along the Earth's magnetic field lines. MTB have been suggested as being one of the most ancient biomineralizing metabolisms on the Earth and they represent a fundamental model of intracellular biomineralization. Moreover, the determination of their specific crystallographic signature (e.g. structure and morphology) is essential for palaeoenvironmental and ancient-life studies. Yet, the mechanisms of MTB biomineralization remain poorly understood, although this process has been extensively studied in several cultured MTB strains in the Proteobacteria phylum. Here, we show a comprehensive transmission electron microscopy (TEM) study of magnetic and structural properties down to atomic scales on bullet-shaped magnetites produced by the uncultured strain MYR-1 belonging to the Nitrospirae phylum, a deeply branching phylogenetic MTB group. We observed a multiple-step crystal growth of MYR-1 magnetite: initial isotropic growth forming cubo-octahedral particles (less than approx. 40 nm), subsequent anisotropic growth and a systematic final elongation along [001] direction. During the crystal growth, one major {111} face is well developed and preserved at the larger basal end of the crystal. The basal {111} face appears to be terminated by a tetrahedral-octahedral-mixed iron surface, suggesting dimensional advantages for binding protein(s), which may template the crystallization of magnetite. This study offers new insights for understanding magnetite biomineralization within the Nitrospirae phylum.
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Affiliation(s)
- Jinhua Li
- Paleomagnetism and Geochronology Lab, Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, People's Republic of China Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC), Sorbonne Universités-UPMC Univ Paris 06, UMR CNRS 7590, Muséum National d'Histoire Naturelle (MNHN), IRD UMR 206, 4 Place Jussieu, Paris 75005, France France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of Sciences, Beijing 100029, People's Republic of China
| | - Nicolas Menguy
- Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC), Sorbonne Universités-UPMC Univ Paris 06, UMR CNRS 7590, Muséum National d'Histoire Naturelle (MNHN), IRD UMR 206, 4 Place Jussieu, Paris 75005, France
| | | | | | | | | | - Eric Leroy
- France Chimie Métallurgique des Terres Rares, ICMPE, UMR 7182, CNRS, 2-8 rue Henri Dunant, Thiais Cedex 94320, France
| | - Yongxin Pan
- Paleomagnetism and Geochronology Lab, Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, People's Republic of China France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of Sciences, Beijing 100029, People's Republic of China
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13
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Magnetotactic bacteria as potential sources of bioproducts. Mar Drugs 2015; 13:389-430. [PMID: 25603340 PMCID: PMC4306944 DOI: 10.3390/md13010389] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/17/2014] [Indexed: 11/16/2022] Open
Abstract
Magnetotactic bacteria (MTB) produce intracellular organelles called magnetosomes which are magnetic nanoparticles composed of magnetite (Fe3O4) or greigite (Fe3S4) enveloped by a lipid bilayer. The synthesis of a magnetosome is through a genetically controlled process in which the bacterium has control over the composition, direction of crystal growth, and the size and shape of the mineral crystal. As a result of this control, magnetosomes have narrow and uniform size ranges, relatively specific magnetic and crystalline properties, and an enveloping biological membrane. These features are not observed in magnetic particles produced abiotically and thus magnetosomes are of great interest in biotechnology. Most currently described MTB have been isolated from saline or brackish environments and the availability of their genomes has contributed to a better understanding and culturing of these fastidious microorganisms. Moreover, genome sequences have allowed researchers to study genes related to magnetosome production for the synthesis of magnetic particles for use in future commercial and medical applications. Here, we review the current information on the biology of MTB and apply, for the first time, a genome mining strategy on these microorganisms to search for secondary metabolite synthesis genes. More specifically, we discovered that the genome of the cultured MTB Magnetovibrio blakemorei, among other MTB, contains several metabolic pathways for the synthesis of secondary metabolites and other compounds, thereby raising the possibility of the co-production of new bioactive molecules along with magnetosomes by this species.
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14
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Nudelman H, Zarivach R. Structure prediction of magnetosome-associated proteins. Front Microbiol 2014; 5:9. [PMID: 24523717 PMCID: PMC3905215 DOI: 10.3389/fmicb.2014.00009] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 01/08/2014] [Indexed: 01/23/2023] Open
Abstract
Magnetotactic bacteria (MTB) are Gram-negative bacteria that can navigate along geomagnetic fields. This ability is a result of a unique intracellular organelle, the magnetosome. These organelles are composed of membrane-enclosed magnetite (Fe3O4) or greigite (Fe3S4) crystals ordered into chains along the cell. Magnetosome formation, assembly, and magnetic nano-crystal biomineralization are controlled by magnetosome-associated proteins (MAPs). Most MAP-encoding genes are located in a conserved genomic region – the magnetosome island (MAI). The MAI appears to be conserved in all MTB that were analyzed so far, although the MAI size and organization differs between species. It was shown that MAI deletion leads to a non-magnetic phenotype, further highlighting its important role in magnetosome formation. Today, about 28 proteins are known to be involved in magnetosome formation, but the structures and functions of most MAPs are unknown. To reveal the structure–function relationship of MAPs we used bioinformatics tools in order to build homology models as a way to understand their possible role in magnetosome formation. Here we present a predicted 3D structural models’ overview for all known Magnetospirillum gryphiswaldense strain MSR-1 MAPs.
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Affiliation(s)
- Hila Nudelman
- Department of Life Sciences, Ben-Gurion University of the Negev Beer Sheva, Israel ; National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Beer Sheva, Israel
| | - Raz Zarivach
- Department of Life Sciences, Ben-Gurion University of the Negev Beer Sheva, Israel ; National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Beer Sheva, Israel
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Tester CC, Joester D. Precipitation in Liposomes as a Model for Intracellular Biomineralization. Methods Enzymol 2013; 532:257-76. [DOI: 10.1016/b978-0-12-416617-2.00012-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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