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Liu L, Huang B, Lu Y, Zhao Y, Tang X, Shi Y. Interactions between electromagnetic radiation and biological systems. iScience 2024; 27:109201. [PMID: 38433903 PMCID: PMC10906530 DOI: 10.1016/j.isci.2024.109201] [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] [Indexed: 03/05/2024] Open
Abstract
Even though the bioeffects of electromagnetic radiation (EMR) have been extensively investigated during the past several decades, our understandings of the bioeffects of EMR and the mechanisms of the interactions between the biological systems and the EMRs are still far from satisfactory. In this article, we introduce and summarize the consensus, controversy, limitations, and unsolved issues. The published works have investigated the EMR effects on different biological systems including humans, animals, cells, and biochemical reactions. Alternative methodologies also include dielectric spectroscopy, detection of bioelectromagnetic emissions, and theoretical predictions. In many studies, the thermal effects of the EMR are not properly controlled or considered. The frequency of the EMR investigated is limited to the commonly used bands, particularly the frequencies of the power line and the wireless communications; far fewer studies were performed for other EMR frequencies. In addition, the bioeffects of the complex EM environment were rarely discussed. In summary, our understanding of the bioeffects of the EMR is quite restrictive and further investigations are needed to answer the unsolved questions.
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Affiliation(s)
- Lingyu Liu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Huang
- Brain Function and Disease Laboratory, Department of Pharmacology, Shantou University Medical College, 22 Xin-Ling Road, Shantou 515041, China
| | - Yingxian Lu
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yanyu Zhao
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Xiaping Tang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
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Awal RP, Müller FD, Pfeiffer D, Monteil CL, Perrière G, Lefèvre CT, Schüler D. Experimental analysis of diverse actin-like proteins from various magnetotactic bacteria by functional expression in Magnetospirillum gryphiswaldense. mBio 2023; 14:e0164923. [PMID: 37823629 PMCID: PMC10653835 DOI: 10.1128/mbio.01649-23] [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: 06/28/2023] [Accepted: 08/29/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE To efficiently navigate within the geomagnetic field, magnetotactic bacteria (MTB) align their magnetosome organelles into chains, which are organized by the actin-like MamK protein. Although MamK is the most highly conserved magnetosome protein common to all MTB, its analysis has been confined to a small subgroup owing to the inaccessibility of most MTB. Our study takes advantage of a genetically tractable host where expression of diverse MamK orthologs together with a resurrected MamK LUCA and uncharacterized actin-like Mad28 proteins from deep-branching MTB resulted in gradual restoration of magnetosome chains in various mutants. Our results further indicate the existence of species-specific MamK interactors and shed light on the evolutionary relationships of one of the key proteins associated with bacterial magnetotaxis.
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Affiliation(s)
- Ram Prasad Awal
- Department of Microbiology, Universitat Bayreuth, Bayreuth, Germany
| | - Frank D. Müller
- Department of Microbiology, Universitat Bayreuth, Bayreuth, Germany
| | - Daniel Pfeiffer
- Department of Microbiology, Universitat Bayreuth, Bayreuth, Germany
| | - Caroline L. Monteil
- Aix-Marseille Université, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, Saint-Paul-lez-Durance, France
| | - Guy Perrière
- Laboratoire de Biométrie et Biologie Evolutive, Université Claude Bernard-Lyon 1, Villeurbanne, France
| | - Christopher T. Lefèvre
- Aix-Marseille Université, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, Saint-Paul-lez-Durance, France
| | - Dirk Schüler
- Department of Microbiology, Universitat Bayreuth, Bayreuth, Germany
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3
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Awal RP, Lefevre CT, Schüler D. Functional expression of foreign magnetosome genes in the alphaproteobacterium Magnetospirillum gryphiswaldense. mBio 2023; 14:e0328222. [PMID: 37318230 PMCID: PMC10470508 DOI: 10.1128/mbio.03282-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/03/2023] [Indexed: 06/16/2023] Open
Abstract
Magnetosomes of magnetotactic bacteria (MTB) consist of structurally perfect, nano-sized magnetic crystals enclosed within vesicles of a proteo-lipid membrane. In species of Magnetospirillum, biosynthesis of their cubo-octahedral-shaped magnetosomes was recently demonstrated to be a complex process, governed by about 30 specific genes that are comprised within compact magnetosome gene clusters (MGCs). Similar, yet distinct gene clusters were also identified in diverse MTB that biomineralize magnetosome crystals with different, genetically encoded morphologies. However, since most representatives of these groups are inaccessible by genetic and biochemical approaches, their analysis will require the functional expression of magnetosome genes in foreign hosts. Here, we studied whether conserved essential magnetosome genes from closely and remotely related MTB can be functionally expressed by rescue of their respective mutants in the tractable model Magnetospirillum gryphiswaldense of the Alphaproteobacteria. Upon chromosomal integration, single orthologues from other magnetotactic Alphaproteobacteria restored magnetosome biosynthesis to different degrees, while orthologues from distantly related Magnetococcia and Deltaproteobacteria were found to be expressed but failed to re-induce magnetosome biosynthesis, possibly due to poor interaction with their cognate partners within multiprotein magnetosome organelle of the host. Indeed, co-expression of the known interactors MamB and MamM from the alphaproteobacterium Magnetovibrio blakemorei increased functional complementation. Furthermore, a compact and portable version of the entire MGCs of M. magneticum was assembled by transformation-associated recombination cloning, and it restored the ability to biomineralize magnetite both in deletion mutants of the native donor and M. gryphiswaldense, while co-expression of gene clusters from both M. gryphiswaldense and M. magneticum resulted in overproduction of magnetosomes. IMPORTANCE We provide proof of principle that Magnetospirillum gryphiswaldense is a suitable surrogate host for the functional expression of foreign magnetosome genes and extended the transformation-associated recombination cloning platform for the assembly of entire large magnetosome gene cluster, which could then be transplanted to different magnetotactic bacteria. The reconstruction, transfer, and analysis of gene sets or entire magnetosome clusters will be also promising for engineering the biomineralization of magnetite crystals with different morphologies that would be valuable for biotechnical applications.
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Affiliation(s)
- Ram Prasad Awal
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Christopher T. Lefevre
- Aix-Marseille Université, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, Saint-Paul-lez-Durance, France
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
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4
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Richter P, Melzer B, Müller FD. Interacting bactofilins impact cell shape of the MreB-less multicellular Rhodomicrobium vannielii. PLoS Genet 2023; 19:e1010788. [PMID: 37256900 DOI: 10.1371/journal.pgen.1010788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 05/16/2023] [Indexed: 06/02/2023] Open
Abstract
Most non-spherical bacteria rely on the actin-like MreB cytoskeleton to control synthesis of a cell-shaping and primarily rod-like cell wall. Diverging from simple rod shape generally requires accessory cytoskeletal elements, which locally interfere with the MreB-guided cell wall synthesis. Conserved and widespread representatives of this accessory cytoskeleton are bactofilins that polymerize into static, non-polar bundles of filaments. Intriguingly, many species of the Actinobacteria and Rhizobiales manage to grow rod-like without MreB by tip extension, yet some of them still possess bactofilin genes, whose function in cell morphogenesis is unknown. An intricate representative of these tip-growing bacteria is Rhodomicrobium vannielii; a member of the hitherto genetically not tractable and poorly studied Hyphomicrobiaceae within the MreB-less Rhizobiales order. R. vannielii displays complex asymmetric cell shapes and differentiation patterns including filamentous hyphae to produce offspring and to build dendritic multicellular arrays. Here, we introduce techniques to genetically access R. vannielii, and we elucidate the role of bactofilins in its sophisticated morphogenesis. By targeted mutagenesis and fluorescence microscopy, protein interaction studies and peptidoglycan incorporation analysis we show that the R. vannielii bactofilins are associated with the hyphal growth zones and that one of them is essential to form proper hyphae. Another paralog is suggested to represent a novel hybrid and co-polymerizing bactofilin. Notably, we present R. vannielii as a powerful new model to understand prokaryotic cell development and control of multipolar cell growth in the absence of the conserved cytoskeletal element, MreB.
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Affiliation(s)
- Pia Richter
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
- Faculty of Biology, University of Marburg, Marburg, Germany
| | - Brigitte Melzer
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
- Max Rubner-Institute, Federal Research Institute of Nutrition and Food, Kulmbach, Germany
| | - Frank D Müller
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
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Chevrier DM, Juhin A, Menguy N, Bolzoni R, Soto-Rodriguez PED, Kojadinovic-Sirinelli M, Paterson GA, Belkhou R, Williams W, Skouri-Panet F, Kosta A, Le Guenno H, Pereiro E, Faivre D, Benzerara K, Monteil CL, Lefevre CT. Collective magnetotaxis of microbial holobionts is optimized by the three-dimensional organization and magnetic properties of ectosymbionts. Proc Natl Acad Sci U S A 2023; 120:e2216975120. [PMID: 36848579 PMCID: PMC10013862 DOI: 10.1073/pnas.2216975120] [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: 10/04/2022] [Accepted: 01/17/2023] [Indexed: 03/01/2023] Open
Abstract
Over the last few decades, symbiosis and the concept of holobiont-a host entity with a population of symbionts-have gained a central role in our understanding of life functioning and diversification. Regardless of the type of partner interactions, understanding how the biophysical properties of each individual symbiont and their assembly may generate collective behaviors at the holobiont scale remains a fundamental challenge. This is particularly intriguing in the case of the newly discovered magnetotactic holobionts (MHB) whose motility relies on a collective magnetotaxis (i.e., a magnetic field-assisted motility guided by a chemoaerotaxis system). This complex behavior raises many questions regarding how magnetic properties of symbionts determine holobiont magnetism and motility. Here, a suite of light-, electron- and X-ray-based microscopy techniques [including X-ray magnetic circular dichroism (XMCD)] reveals that symbionts optimize the motility, the ultrastructure, and the magnetic properties of MHBs from the microscale to the nanoscale. In the case of these magnetic symbionts, the magnetic moment transferred to the host cell is in excess (102 to 103 times stronger than free-living magnetotactic bacteria), well above the threshold for the host cell to gain a magnetotactic advantage. The surface organization of symbionts is explicitly presented herein, depicting bacterial membrane structures that ensure longitudinal alignment of cells. Magnetic dipole and nanocrystalline orientations of magnetosomes were also shown to be consistently oriented in the longitudinal direction, maximizing the magnetic moment of each symbiont. With an excessive magnetic moment given to the host cell, the benefit provided by magnetosome biomineralization beyond magnetotaxis can be questioned.
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Affiliation(s)
- Daniel M. Chevrier
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
| | - Amélie Juhin
- Sorbonne Université, UMR CNRS 7590, Muséum national d'Histoire naturelle (MNHN), Institut de recherche pour le développement (IRD), Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 75005Paris, France
| | - Nicolas Menguy
- Sorbonne Université, UMR CNRS 7590, Muséum national d'Histoire naturelle (MNHN), Institut de recherche pour le développement (IRD), Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 75005Paris, France
| | - Romain Bolzoni
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
| | - Paul E. D. Soto-Rodriguez
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
| | - Mila Kojadinovic-Sirinelli
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
| | - Greig A. Paterson
- Department of Earth, Ocean and Ecological Sciences, University of Liverpool, L69 7ZELiverpool, UK
| | - Rachid Belkhou
- Synchrotron Soleil, L'Orme des Merisiers, 91192Gif-sur-Yvette Cedex, France
| | - Wyn Williams
- School of GeoSciences, Grant Institute, University of Edinburgh, EdinburghEH9 3JW, UK
| | - Fériel Skouri-Panet
- Sorbonne Université, UMR CNRS 7590, Muséum national d'Histoire naturelle (MNHN), Institut de recherche pour le développement (IRD), Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 75005Paris, France
| | - Artemis Kosta
- Plateforme de Microscopie de l'Institut de Microbiologie de la Méditerranée, Institut de Microbiologie, FR3479, Campus CNRS, 13402Marseille cedex 20, France
| | - Hugo Le Guenno
- Plateforme de Microscopie de l'Institut de Microbiologie de la Méditerranée, Institut de Microbiologie, FR3479, Campus CNRS, 13402Marseille cedex 20, France
| | - Eva Pereiro
- ALBA Synchrotron Light Source, Cerdanyola del Vallés, Barcelona08290, Spain
| | - Damien Faivre
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
| | - Karim Benzerara
- Sorbonne Université, UMR CNRS 7590, Muséum national d'Histoire naturelle (MNHN), Institut de recherche pour le développement (IRD), Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 75005Paris, France
| | - Caroline L. Monteil
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
| | - Christopher T. Lefevre
- Aix-Marseille Université, Centre national de la recherche scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), UMR7265, Bioscience and biotechnology institute of Aix-Marseille (BIAM), Saint-Paul-lez-Durance13108, France
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Dziuba MV, Paulus A, Schramm L, Awal RP, Pósfai M, Monteil CL, Fouteau S, Uebe R, Schüler D. Silent gene clusters encode magnetic organelle biosynthesis in a non-magnetotactic phototrophic bacterium. THE ISME JOURNAL 2023; 17:326-339. [PMID: 36517527 PMCID: PMC9938234 DOI: 10.1038/s41396-022-01348-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/15/2022]
Abstract
Horizontal gene transfer is a powerful source of innovations in prokaryotes that can affect almost any cellular system, including microbial organelles. The formation of magnetosomes, one of the most sophisticated microbial mineral-containing organelles synthesized by magnetotactic bacteria for magnetic navigation in the environment, was also shown to be a horizontally transferrable trait. However, the mechanisms determining the fate of such genes in new hosts are not well understood, since non-adaptive gene acquisitions are typically rapidly lost and become unavailable for observation. This likely explains why gene clusters encoding magnetosome biosynthesis have never been observed in non-magnetotactic bacteria. Here, we report the first discovery of a horizontally inherited dormant gene clusters encoding biosynthesis of magnetosomes in a non-magnetotactic phototrophic bacterium Rhodovastum atsumiense. We show that these clusters were inactivated through transcriptional silencing and antisense RNA regulation, but retain functionality, as several genes were able to complement the orthologous deletions in a remotely related magnetotactic bacterium. The laboratory transfer of foreign magnetosome genes to R. atsumiense was found to endow the strain with magnetosome biosynthesis, but strong negative selection led to rapid loss of this trait upon subcultivation, highlighting the trait instability in this organism. Our results provide insight into the horizontal dissemination of gene clusters encoding complex prokaryotic organelles and illuminate the potential mechanisms of their genomic preservation in a dormant state.
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Affiliation(s)
- M. V. Dziuba
- grid.7384.80000 0004 0467 6972Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany
| | - A. Paulus
- grid.7384.80000 0004 0467 6972Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany ,grid.7384.80000 0004 0467 6972Department of Microbial Biochemistry, Faculty of Life Sciences: Food, Nutrition and Health, University of Bayreuth, Bayreuth, Germany
| | - L. Schramm
- grid.7384.80000 0004 0467 6972Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany
| | - R. P. Awal
- grid.7384.80000 0004 0467 6972Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany
| | - M. Pósfai
- ELKH-PE Environmental Mineralogy Research Group, Veszprém, Hungary ,grid.7336.10000 0001 0203 5854Research Institute of Biomolecular and Chemical Engineering, University of Pannonia, Veszprém, Hungary
| | - C. L. Monteil
- grid.5399.60000 0001 2176 4817Aix-Marseille University, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille, Saint Paul lez Durance, France
| | - S. Fouteau
- grid.8390.20000 0001 2180 5818LABGeM, Genomique Metabolique, CEA, Genoscope, Institut Francois Jacob, CNRS, Universite d’Evry, Universite Paris- Saclay, Evry, France
| | - R. Uebe
- grid.7384.80000 0004 0467 6972Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany ,grid.7384.80000 0004 0467 6972Department of Microbial Biochemistry, Faculty of Life Sciences: Food, Nutrition and Health, University of Bayreuth, Bayreuth, Germany
| | - D. Schüler
- grid.7384.80000 0004 0467 6972Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany
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Live-Cell Fluorescence Imaging of Magnetosome Organelle for Magnetotaxis Motility. Methods Mol Biol 2023; 2646:133-146. [PMID: 36842112 DOI: 10.1007/978-1-0716-3060-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
The assessment of intracellular dynamics is crucial for understanding the function and formation process of bacterial organelle, just as it is for the inquisition of their eukaryotic counterparts. The methods for imaging magnetosome organelles in a magnetotactic bacterial cell using live-cell fluorescence imaging by highly inclined and laminated optical sheet (HILO) microscopy are presented in this chapter. Furthermore, we introduce methods for pH imaging in magnetosome lumen as an application of fluorescence magnetosome imaging.
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Wan J, Monteil CL, Taoka A, Ernie G, Park K, Amor M, Taylor-Cornejo E, Lefevre CT, Komeili A. McaA and McaB control the dynamic positioning of a bacterial magnetic organelle. Nat Commun 2022; 13:5652. [PMID: 36163114 PMCID: PMC9512821 DOI: 10.1038/s41467-022-32914-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022] Open
Abstract
Magnetotactic bacteria are a diverse group of microorganisms that use intracellular chains of ferrimagnetic nanocrystals, produced within magnetosome organelles, to align and navigate along the geomagnetic field. Several conserved genes for magnetosome formation have been described, but the mechanisms leading to distinct species-specific magnetosome chain configurations remain unclear. Here, we show that the fragmented nature of magnetosome chains in Magnetospirillum magneticum AMB-1 is controlled by genes mcaA and mcaB. McaA recognizes the positive curvature of the inner cell membrane, while McaB localizes to magnetosomes. Along with the MamK actin-like cytoskeleton, McaA and McaB create space for addition of new magnetosomes in between pre-existing magnetosomes. Phylogenetic analyses suggest that McaA and McaB homologs are widespread among magnetotactic bacteria and may represent an ancient strategy for magnetosome positioning.
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Affiliation(s)
- Juan Wan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Caroline L Monteil
- Aix-Marseille Université, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, 13108, Saint-Paul-lez-Durance, France
| | - Azuma Taoka
- Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Gabriel Ernie
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Kieop Park
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708, USA
| | - Matthieu Amor
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
- Aix-Marseille Université, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, 13108, Saint-Paul-lez-Durance, France
| | - Elias Taylor-Cornejo
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
- Department of Biology, Randolph-Macon College, Ashland, VA, 23005, USA
| | - Christopher T Lefevre
- Aix-Marseille Université, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, 13108, Saint-Paul-lez-Durance, France
| | - Arash Komeili
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA.
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Sesbanimide R, a Novel Cytotoxic Polyketide Produced by Magnetotactic Bacteria. mBio 2021; 12:mBio.00591-21. [PMID: 34006654 PMCID: PMC8262917 DOI: 10.1128/mbio.00591-21] [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] [Indexed: 11/20/2022] Open
Abstract
Genomic information from various magnetotactic bacteria suggested that besides their common ability to form magnetosomes, they potentially also represent a source of bioactive natural products. By using targeted deletion and transcriptional activation, we connected a large biosynthetic gene cluster (BGC) of the trans-acyltransferase polyketide synthase (trans-AT PKS) type to the biosynthesis of a novel polyketide in the alphaproteobacterium Magnetospirillum gryphiswaldense Structure elucidation by mass spectrometry and nuclear magnetic resonance spectroscopy (NMR) revealed that this secondary metabolite resembles sesbanimides, which were very recently reported from other taxa. However, sesbanimide R exhibits an additional arginine moiety the presence of which reconciles inconsistencies in the previously proposed sesbanimide biosynthesis pathway observed when comparing the chemical structure and the potential biochemistry encoded in the BGC. In contrast to the case with sesbanimides D, E, and F, we were able to assign the stereocenter of the arginine moiety experimentally and two of the remaining three stereocenters by predictive biosynthetic tools. Sesbanimide R displayed strong cytotoxic activity against several carcinoma cell lines.IMPORTANCE The findings of this study contribute a new secondary metabolite member to the glutarimide-containing polyketides. The determined structure of sesbanimide R correlates with its cytotoxic bioactivity, characteristic for members of this family. Sesbanimide R represents the first natural product isolated from magnetotactic bacteria and identifies this highly diverse group as a so-far-untapped source for the future discovery of novel secondary metabolites.
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