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Hrdina A, Serra Canales M, Arias-Rojas A, Frahm D, Iatsenko I. The endosymbiont Spiroplasma poulsonii increases Drosophila melanogaster resistance to pathogens by enhancing iron sequestration and melanization. mBio 2024; 15:e0093624. [PMID: 38940615 PMCID: PMC11323552 DOI: 10.1128/mbio.00936-24] [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: 03/28/2024] [Accepted: 05/28/2024] [Indexed: 06/29/2024] Open
Abstract
Facultative endosymbiotic bacteria, such as Wolbachia and Spiroplasma species, are commonly found in association with insects and can dramatically alter their host physiology. Many endosymbionts are defensive and protect their hosts against parasites or pathogens. Despite the widespread nature of defensive insect symbioses and their importance for the ecology and evolution of insects, the mechanisms of symbiont-mediated host protection remain poorly characterized. Here, we utilized the fruit fly Drosophila melanogaster and its facultative endosymbiont Spiroplasma poulsonii to characterize the mechanisms underlying symbiont-mediated host protection against bacterial and fungal pathogens. Our results indicate a variable effect of S. poulsonii on infection outcome, with endosymbiont-harboring flies being more resistant to Rhyzopus oryzae, Staphylococcus aureus, and Providencia alcalifaciens but more sensitive or as sensitive as endosymbiont-free flies to the infections with Pseudomonas species. Further focusing on the protective effect, we identified Transferrin-mediated iron sequestration induced by Spiroplasma as being crucial for the defense against R. oryzae and P. alcalifaciens. In the case of S. aureus, enhanced melanization in Spiroplasma-harboring flies plays a major role in protection. Both iron sequestration and melanization induced by Spiroplasma require the host immune sensor protease Persephone, suggesting a role of proteases secreted by the symbiont in the activation of host defense reactions. Hence, our work reveals a broader defensive range of Spiroplasma than previously appreciated and adds nutritional immunity and melanization to the defensive arsenal of symbionts. IMPORTANCE Defensive endosymbiotic bacteria conferring protection to their hosts against parasites and pathogens are widespread in insect populations. However, the mechanisms by which most symbionts confer protection are not fully understood. Here, we studied the mechanisms of protection against bacterial and fungal pathogens mediated by the Drosophila melanogaster endosymbiont Spiroplasma poulsonii. We demonstrate that besides the previously described protection against wasps and nematodes, Spiroplasma also confers increased resistance to pathogenic bacteria and fungi. We identified Spiroplasma-induced iron sequestration and melanization as key defense mechanisms. Our work broadens the known defense spectrum of Spiroplasma and reveals a previously unappreciated role of melanization and iron sequestration in endosymbiont-mediated host protection. We propose that the mechanisms we have identified here may be of broader significance and could apply to other endosymbionts, particularly to Wolbachia, and potentially explain their protective properties.
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Affiliation(s)
- Alexandra Hrdina
- Research group Genetics of Host-Microbe Interactions, Max Planck Institute for Infection Biology, Berlin, Germany
- Faculty of Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Marina Serra Canales
- Research group Genetics of Host-Microbe Interactions, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Aranzazu Arias-Rojas
- Research group Genetics of Host-Microbe Interactions, Max Planck Institute for Infection Biology, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Dagmar Frahm
- Research group Genetics of Host-Microbe Interactions, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Igor Iatsenko
- Research group Genetics of Host-Microbe Interactions, Max Planck Institute for Infection Biology, Berlin, Germany
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2
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Chakraborty J, Poddar S, Dutta S, Bahulekar V, Harne S, Srinivasan R, Gayathri P. Dynamics of interdomain rotation facilitates FtsZ filament assembly. J Biol Chem 2024; 300:107336. [PMID: 38718863 PMCID: PMC11157280 DOI: 10.1016/j.jbc.2024.107336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/31/2024] Open
Abstract
FtsZ, the tubulin homolog essential for bacterial cell division, assembles as the Z-ring at the division site, and directs peptidoglycan synthesis by treadmilling. It is unclear how FtsZ achieves kinetic polarity that drives treadmilling. To obtain insights into fundamental features of FtsZ assembly dynamics independent of peptidoglycan synthesis, we carried out structural and biochemical characterization of FtsZ from the cell wall-less bacteria, Spiroplasma melliferum (SmFtsZ). Interestingly the structures of SmFtsZ, bound to GDP and GMPPNP respectively, were captured as domain swapped dimers. SmFtsZ was found to be a slower GTPase with a higher critical concentration (CC) compared to Escherichia coli FtsZ (EcFtsZ). In FtsZs, a conformational switch from R-state (close) to T-state (open) favors polymerization. We identified that Phe224, located at the interdomain cleft of SmFtsZ, is crucial for R- to T-state transition. SmFtsZF224M exhibited higher GTPase activity and lower CC, whereas the corresponding EcFtsZM225F resulted in cell division defects in E. coli. Our results demonstrate that relative rotation of the domains is a rate-limiting step of polymerization. Our structural analysis suggests that the rotation is plausibly triggered upon addition of a GTP-bound monomer to the filament through interaction of the preformed N-terminal domain (NTD). Hence, addition of monomers to the NTD-exposed end of filament is slower in comparison to the C-terminal domain (CTD) end, thus explaining kinetic polarity. In summary, the study highlights the importance of interdomain interactions and conformational changes in regulating FtsZ assembly dynamics.
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Affiliation(s)
- Joyeeta Chakraborty
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Sakshi Poddar
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India; Homi Bhabha National Institutes (HBNI), Training School Complex, Mumbai, India
| | - Soumyajit Dutta
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Vaishnavi Bahulekar
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Shrikant Harne
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Ramanujam Srinivasan
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India; Homi Bhabha National Institutes (HBNI), Training School Complex, Mumbai, India
| | - Pananghat Gayathri
- Biology Division, Indian Institute of Science Education and Research, Pune, India.
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3
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Dudek NK, Galaz-Montoya JG, Shi H, Mayer M, Danita C, Celis AI, Viehboeck T, Wu GH, Behr B, Bulgheresi S, Huang KC, Chiu W, Relman DA. Previously uncharacterized rectangular bacterial structures in the dolphin mouth. Nat Commun 2023; 14:2098. [PMID: 37055390 PMCID: PMC10102025 DOI: 10.1038/s41467-023-37638-y] [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: 11/01/2021] [Accepted: 03/23/2023] [Indexed: 04/15/2023] Open
Abstract
Much remains to be explored regarding the diversity of uncultured, host-associated microbes. Here, we describe rectangular bacterial structures (RBSs) in the mouths of bottlenose dolphins. DNA staining revealed multiple paired bands within RBSs, suggesting the presence of cells dividing along the longitudinal axis. Cryogenic transmission electron microscopy and tomography showed parallel membrane-bound segments that are likely cells, encapsulated by an S-layer-like periodic surface covering. RBSs displayed unusual pilus-like appendages with bundles of threads splayed at the tips. We present multiple lines of evidence, including genomic DNA sequencing of micromanipulated RBSs, 16S rRNA gene sequencing, and fluorescence in situ hybridization, suggesting that RBSs are bacterial and distinct from the genera Simonsiella and Conchiformibius (family Neisseriaceae), with which they share similar morphology and division patterning. Our findings highlight the diversity of novel microbial forms and lifestyles that await characterization using tools complementary to genomics such as microscopy.
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Affiliation(s)
- Natasha K Dudek
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
- Quantori, Cambridge, MA, 02142, USA
| | | | - Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Megan Mayer
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Cristina Danita
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Arianna I Celis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Tobias Viehboeck
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Austria
- Division of Microbial Ecology, Center for Microbiology and Environmental Systems Science, and Vienna Doctoral School of Ecology and Evolution, University of Vienna, Vienna, Austria
| | - Gong-Her Wu
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Barry Behr
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Silvia Bulgheresi
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Austria
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Wah Chiu
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - David A Relman
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
- Infectious Diseases Section, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, 94304, USA.
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4
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Nyongesa S, Weber PM, Bernet È, Pulido F, Nieves C, Nieckarz M, Delaby M, Viehboeck T, Krause N, Rivera-Millot A, Nakamura A, Vischer NOE, vanNieuwenhze M, Brun YV, Cava F, Bulgheresi S, Veyrier FJ. Evolution of longitudinal division in multicellular bacteria of the Neisseriaceae family. Nat Commun 2022; 13:4853. [PMID: 35995772 PMCID: PMC9395523 DOI: 10.1038/s41467-022-32260-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Rod-shaped bacteria typically elongate and divide by transverse fission. However, several bacterial species can form rod-shaped cells that divide longitudinally. Here, we study the evolution of cell shape and division mode within the family Neisseriaceae, which includes Gram-negative coccoid and rod-shaped species. In particular, bacteria of the genera Alysiella, Simonsiella and Conchiformibius, which can be found in the oral cavity of mammals, are multicellular and divide longitudinally. We use comparative genomics and ultrastructural microscopy to infer that longitudinal division within Neisseriaceae evolved from a rod-shaped ancestor. In multicellular longitudinally-dividing species, neighbouring cells within multicellular filaments are attached by their lateral peptidoglycan. In these bacteria, peptidoglycan insertion does not appear concentric, i.e. from the cell periphery to its centre, but as a medial sheet guillotining each cell. Finally, we identify genes and alleles associated with multicellularity and longitudinal division, including the acquisition of amidase-encoding gene amiC2, and amino acid changes in proteins including MreB and FtsA. Introduction of amiC2 and allelic substitution of mreB in a rod-shaped species that divides by transverse fission results in shorter cells with longer septa. Our work sheds light on the evolution of multicellularity and longitudinal division in bacteria, and suggests that members of the Neisseriaceae family may be good models to study these processes due to their morphological plasticity and genetic tractability. Rod-shaped bacteria typically elongate and divide by transverse fission, but a few species are known to divide longitudinally. Here, the authors use genomic, phylogenetic and microscopy techniques to shed light on the evolution of cell shape, multicellularity and division mode within the family Neisseriaceae.
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Affiliation(s)
- Sammy Nyongesa
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada
| | - Philipp M Weber
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Djerassiplatz 1, 1030, Vienna, Austria.,University of Vienna, Vienna Doctoral School of Ecology and Evolution, Vienna, Austria
| | - Ève Bernet
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada
| | - Francisco Pulido
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada
| | - Cecilia Nieves
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada
| | - Marta Nieckarz
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, SE-90187, Sweden
| | - Marie Delaby
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, QC, Canada
| | - Tobias Viehboeck
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Djerassiplatz 1, 1030, Vienna, Austria.,University of Vienna, Vienna Doctoral School of Ecology and Evolution, Vienna, Austria.,Division of Microbial Ecology, Center for Microbiology and Environmental Systems Science, , University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Nicole Krause
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Djerassiplatz 1, 1030, Vienna, Austria.,University of Vienna, Vienna Doctoral School of Ecology and Evolution, Vienna, Austria
| | - Alex Rivera-Millot
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada
| | - Arnaldo Nakamura
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada
| | - Norbert O E Vischer
- Bacterial Cell Biology & Physiology, Swammerdam Institute of Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098, Amsterdam, the Netherlands
| | | | - Yves V Brun
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, QC, Canada
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, SE-90187, Sweden
| | - Silvia Bulgheresi
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
| | - Frédéric J Veyrier
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, QC, H7V 1B7, Canada.
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5
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Masson F, Pierrat X, Lemaitre B, Persat A. The wall-less bacterium Spiroplasma poulsonii builds a polymeric cytoskeleton composed of interacting MreB isoforms. iScience 2021; 24:103458. [PMID: 34888500 PMCID: PMC8634037 DOI: 10.1016/j.isci.2021.103458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/03/2021] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
A rigid cell wall defines the morphology of most bacteria. MreB, a bacterial homologue of actin, plays a major role in coordinating cell wall biogenesis and defining cell shape. Spiroplasma are wall-less bacteria that robustly grow with a characteristic helical shape. Paradoxal to their lack of cell wall, the Spiroplasma genome contains five homologs of MreB (SpMreBs). Here, we investigate the function of SpMreBs in forming a polymeric cytoskeleton. We found that, in vivo, Spiroplasma maintain a high concentration of all MreB isoforms. By leveraging a heterologous expression system that bypasses the poor genetic tractability of Spiroplasma, we found that SpMreBs produced polymeric filaments of various morphologies. We characterized an interaction network between isoforms that regulate filament formation and patterning. Therefore, our results support the hypothesis where combined SpMreB isoforms would form an inner polymeric cytoskeleton in vivo that shapes the cell in a wall-independent manner. The five Spiroplasma MreB isoforms are extremely abundant proteins in vivo Each isoform produces filaments when expressed in a heterologous system SpMreBs form an interaction network that regulates filament length and shape
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Affiliation(s)
- Florent Masson
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Corresponding author
| | - Xavier Pierrat
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Bruno Lemaitre
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Alexandre Persat
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Corresponding author
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6
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Xiao X, Willemse J, Voskamp P, Li X, Prota AE, Lamers M, Pannu N, Abrahams JP, van Wezel GP. Ectopic positioning of the cell division plane is associated with single amino acid substitutions in the FtsZ-recruiting SsgB in Streptomyces. Open Biol 2021; 11:200409. [PMID: 33622102 PMCID: PMC8061694 DOI: 10.1098/rsob.200409] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In most bacteria, cell division begins with the polymerization of the GTPase FtsZ at mid-cell, which recruits the division machinery to initiate cell constriction. In the filamentous bacterium Streptomyces, cell division is positively controlled by SsgB, which recruits FtsZ to the future septum sites and promotes Z-ring formation. Here, we show that various amino acid (aa) substitutions in the highly conserved SsgB protein result in ectopically placed septa that sever spores diagonally or along the long axis, perpendicular to the division plane. Fluorescence microscopy revealed that between 3.3% and 9.8% of the spores of strains expressing SsgB E120 variants were severed ectopically. Biochemical analysis of SsgB variant E120G revealed that its interaction with FtsZ had been maintained. The crystal structure of Streptomyces coelicolor SsgB was resolved and the key residues were mapped on the structure. Notably, residue substitutions (V115G, G118V, E120G) that are associated with septum misplacement localize in the α2-α3 loop region that links the final helix and the rest of the protein. Structural analyses and molecular simulation revealed that these residues are essential for maintaining the proper angle of helix α3. Our data suggest that besides altering FtsZ, aa substitutions in the FtsZ-recruiting protein SsgB also lead to diagonally or longitudinally divided cells in Streptomyces.
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Affiliation(s)
- Xiansha Xiao
- Molecular Biotechnology, Leiden University, PO Box 9505, 2300RA Leiden, The Netherlands
| | - Joost Willemse
- Molecular Biotechnology, Leiden University, PO Box 9505, 2300RA Leiden, The Netherlands
| | - Patrick Voskamp
- Biophysical Structural Chemistry, Leiden University, PO Box 9502, 2300RA Leiden, The Netherlands
| | - Xinmeng Li
- LIC/Energy and Sustainability, Leiden University, PO Box 9502, 2300RA Leiden, The Netherlands
| | | | - Meindert Lamers
- Leiden University Medical Center, PO Box 9600, 2300RC Leiden, The Netherlands
| | - Navraj Pannu
- Biophysical Structural Chemistry, Leiden University, PO Box 9502, 2300RA Leiden, The Netherlands
| | - Jan Pieter Abrahams
- Molecular Biotechnology, Leiden University, PO Box 9505, 2300RA Leiden, The Netherlands.,Paul Scherrer Institute, CH-5232 Villigen, Switzerland.,Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Gilles P van Wezel
- Molecular Biotechnology, Leiden University, PO Box 9505, 2300RA Leiden, The Netherlands
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7
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Harne S, Duret S, Pande V, Bapat M, Béven L, Gayathri P. MreB5 Is a Determinant of Rod-to-Helical Transition in the Cell-Wall-less Bacterium Spiroplasma. Curr Biol 2020; 30:4753-4762.e7. [PMID: 32976813 DOI: 10.1016/j.cub.2020.08.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/05/2020] [Accepted: 08/26/2020] [Indexed: 12/22/2022]
Abstract
In most rod-shaped bacteria, the spatial coordination of cell wall synthesis machinery by MreBs is the main theme for shape determination and maintenance in cell-walled bacteria [1-9]. However, how rod or spiral shapes are achieved and maintained in cell-wall-less bacteria is currently unknown. Spiroplasma, a helical Mollicute that lacks cell wall synthesis genes, encodes five MreB paralogs and a unique cytoskeletal protein fibril [10, 11]. Here, we show that MreB5, one of the five MreB paralogs, contributes to cell elongation and is essential for the transition from rod-to-helical shape in Spiroplasma. Comparative genomic and proteomic characterization of a helical and motile wild-type Spiroplasma strain and a non-helical, non-motile natural variant helped delineate the specific roles of MreB5. Moreover, complementation of the non-helical strain with MreB5 restored its helical shape and motility by a kink-based mechanism described for Spiroplasma [12]. Earlier studies had proposed that length changes in fibril filaments are responsible for the change in handedness of the helical cell and kink propagation during motility [13]. Through structural and biochemical characterization, we identify that MreB5 exists as antiparallel double protofilaments that interact with fibril and the membrane, and thus potentially assists in kink propagation. In summary, our study provides direct experimental evidence for MreB in maintaining cell length, helical shape, and motility-revealing the role of MreB in sculpting the cell in the absence of a cell wall.
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Sybille Duret
- INRAE, University of Bordeaux, UMR 1332 BFP, Villenave d'Ornon, Bordeaux, France
| | - Vani Pande
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Mrinmayee Bapat
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Laure Béven
- INRAE, University of Bordeaux, UMR 1332 BFP, Villenave d'Ornon, Bordeaux, France.
| | - Pananghat Gayathri
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
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8
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Harne S, Gayathri P, Béven L. Exploring Spiroplasma Biology: Opportunities and Challenges. Front Microbiol 2020; 11:589279. [PMID: 33193251 PMCID: PMC7609405 DOI: 10.3389/fmicb.2020.589279] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/28/2020] [Indexed: 11/13/2022] Open
Abstract
Spiroplasmas are cell-wall-deficient helical bacteria belonging to the class Mollicutes. Their ability to maintain a helical shape in the absence of cell wall and their motility in the absence of external appendages have attracted attention from the scientific community for a long time. In this review we compare and contrast motility, shape determination and cytokinesis mechanisms of Spiroplasma with those of other Mollicutes and cell-walled bacteria. The current models for rod-shape determination and cytokinesis in cell-walled bacteria propose a prominent role for the cell wall synthesis machinery. These models also involve the cooperation of the actin-like protein MreB and FtsZ, the bacterial homolog of tubulin. However the exact role of the cytoskeletal proteins is still under much debate. Spiroplasma possess MreBs, exhibit a rod-shape dependent helical morphology, and divide by an FtsZ-dependent mechanism. Hence, spiroplasmas represent model organisms for deciphering the roles of MreBs and FtsZ in fundamental mechanisms of non-spherical shape determination and cytokinesis in bacteria, in the absence of a cell wall. Identification of components implicated in these processes and deciphering their functions would require genetic experiments. Challenges in genetic manipulations in spiroplasmas are a major bottleneck in understanding their biology. We discuss advancements in genome sequencing, gene editing technologies, super-resolution microscopy and electron cryomicroscopy and tomography, which can be employed for addressing long-standing questions related to Spiroplasma biology.
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research, Pune, India
| | | | - Laure Béven
- INRAE, UMR 1332, Biologie du Fruit et Pathologie, University of Bordeaux, Bordeaux, France
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9
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Transformation of the Drosophila Sex-Manipulative Endosymbiont Spiroplasma poulsonii and Persisting Hurdles for Functional Genetic Studies. Appl Environ Microbiol 2020; 86:AEM.00835-20. [PMID: 32444468 DOI: 10.1128/aem.00835-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/12/2020] [Indexed: 01/07/2023] Open
Abstract
Insects are frequently infected by bacterial symbionts that greatly affect their physiology and ecology. Most of these endosymbionts are, however, barely tractable outside their native host, rendering functional genetics studies difficult or impossible. Spiroplasma poulsonii is a facultative bacterial endosymbiont of Drosophila melanogaster that manipulates the reproduction of its host by killing its male progeny at the embryonic stage. S. poulsonii, although a very fastidious bacterium, is closely related to pathogenic Spiroplasma species that are cultivable and genetically modifiable. In this work, we present the transformation of S. poulsonii with a plasmid bearing a fluorescence cassette, leveraging techniques adapted from those used to modify the pathogenic species Spiroplasma citri We demonstrate the feasibility of S. poulsonii transformation and discuss approaches for mutant selection and fly colonization, which are persisting hurdles that must be overcome to allow functional bacterial genetics studies of this endosymbiont in vivo IMPORTANCE Dozens of bacterial endosymbiont species have been described and estimated to infect about half of all insect species. However, only a few them are tractable in vitro, which hampers our understanding of the bacterial determinants of the host-symbiont interaction. Developing a transformation method for S. poulsonii is a major step toward genomic engineering of this symbiont, which will foster basic research on endosymbiosis. This could also open the way to practical uses of endosymbiont engineering through paratransgenesis of vector or pest insects.
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Yeoman CJ, Brutscher LM, Esen ÖC, Ibaoglu F, Fowler C, Eren AM, Wanner K, Weaver DK. Genome-resolved insights into a novel Spiroplasma symbiont of the Wheat Stem Sawfly ( Cephus cinctus). PeerJ 2019; 7:e7548. [PMID: 31523509 PMCID: PMC6716498 DOI: 10.7717/peerj.7548] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/25/2019] [Indexed: 12/24/2022] Open
Abstract
Arthropods often have obligate relationships with symbiotic microbes, and recent investigations have demonstrated that such host-microbe relationships could be exploited to suppress natural populations of vector carrying mosquitos. Strategies that target the interplay between agricultural pests and their symbionts could decrease the burden caused by agricultural pests; however, the lack of comprehensive genomic insights into naturally occurring microbial symbionts presents a significant bottleneck. Here we employed amplicon surveys, genome-resolved metagenomics, and scanning electron microscopy to investigate symbionts of the wheat stem sawfly (Cephus cinctus), a major pest that causes an estimated $350 million dollars or more in wheat yield losses in the northwestern United States annually. Through 16S rRNA gene sequencing of two major haplotypes and life stages of wheat stem sawfly, we show a novel Spiroplasma species is ever-present and predominant, with phylogenomic analyses placing it as a member of the ixodetis clade of mollicutes. Using state-of-the-art metagenomic assembly and binning strategies we were able to reconstruct a 714 Kb, 72.7%-complete Spiroplasma genome, which represents just the second draft genome from the ixodetis clade of mollicutes. Functional annotation of the Spiroplasma genome indicated carbohydrate-metabolism involved PTS-mediated import of glucose and fructose followed by glycolysis to lactate, acetate, and propionoate. The bacterium also encoded biosynthetic pathways for essential vitamins B2, B3, and B9. We identified putative Spiroplasma virulence genes: cardiolipin and chitinase. These results identify a previously undescribed symbiosis between wheat stem sawfly and a novel Spiroplasma sp., availing insight into their molecular relationship, and may yield new opportunities for microbially-mediated pest control strategies.
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Affiliation(s)
- Carl J Yeoman
- Department of Animal & Range Sciences, Montana State University, Bozeman, MT, United States of America
| | - Laura M Brutscher
- Department of Animal & Range Sciences, Montana State University, Bozeman, MT, United States of America.,Department of Microbiology & Immunology, Montana State University, Bozeman, MT, United States of America
| | - Özcan C Esen
- Department of Medicine, University of Chicago, Chicago, IL, United States of America
| | - Furkan Ibaoglu
- Department of Animal & Range Sciences, Montana State University, Bozeman, MT, United States of America.,Department of Microbiology & Immunology, Montana State University, Bozeman, MT, United States of America
| | - Curtis Fowler
- Department of Animal & Range Sciences, Montana State University, Bozeman, MT, United States of America
| | - A Murat Eren
- Department of Medicine, University of Chicago, Chicago, IL, United States of America.,Marine Biological Laboratory, The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Woods Hole, Massachuetts, United States of America
| | - Kevin Wanner
- Department of Plant Sciences & Plant Pathology, Montana State University, Bozeman, MT, United States of America
| | - David K Weaver
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States of America
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Vedyaykin AD, Ponomareva EV, Khodorkovskii MA, Borchsenius SN, Vishnyakov IE. Mechanisms of Bacterial Cell Division. Microbiology (Reading) 2019. [DOI: 10.1134/s0026261719030159] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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Abstract
The last three decades have witnessed an explosion of discoveries about the mechanistic details of binary fission in model bacteria such as Escherichia coli, Bacillus subtilis, and Caulobacter crescentus. This was made possible not only by advances in microscopy that helped answer questions about cell biology but also by clever genetic manipulations that directly and easily tested specific hypotheses. More recently, research using understudied organisms, or nonmodel systems, has revealed several alternate mechanistic strategies that bacteria use to divide and propagate. In this review, we highlight new findings and compare these strategies to cell division mechanisms elucidated in model organisms.
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Affiliation(s)
- Prahathees J Eswara
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida 33620;
| | - Kumaran S Ramamurthi
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-5132;
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