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Tang S, Pichugin Y, Hammerschmidt K. An environmentally induced multicellular life cycle of a unicellular cyanobacterium. Curr Biol 2023; 33:764-769.e5. [PMID: 36854263 DOI: 10.1016/j.cub.2023.01.069] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/19/2022] [Accepted: 01/04/2023] [Indexed: 03/02/2023]
Abstract
Understanding the evolutionary transition to multicellularity is a key problem in biology.1,2,3,4 Nevertheless, the ecological conditions driving such transitions are not well understood. The first known transition to multicellularity occurred 2.5 billion years ago in cyanobacteria,5,6,7 and today's cyanobacteria are characterized by enormous morphological diversity. They range from unicellular species; unicellular cyanobacteria with packet-like phenotypes, e.g., tetrads; and simple filamentous species to highly differentiated filamentous species.8,9,10 The cyanobacterium Cyanothece sp. ATCC 51142, an isolate from the intertidal zone of the U.S. Gulf Coast,11 was classified as a unicellular species.12 We report a facultative life cycle of Cyanothece sp. in which multicellular filaments alternate with unicellular stages. In a series of experiments, we identified salinity and population density as environmental factors triggering the phenotypic switch between the two morphologies. Then, we used numerical models to test hypotheses regarding the nature of the environmental cues and the mechanisms underlying filament dissolution. While the results predict that the observed response is likely caused by an excreted compound in the medium, we cannot fully exclude changes in nutrient availability (as in Tuomi et al.13 and Matz and Jürgens14). The best-fit modeling results show a nonlinear effect of the compound, which is characteristic of density-dependent sensing systems.15,16 Furthermore, filament fragmentation is predicted to occur by connection cleavage rather than cell death of each alternating cell, which is supported by fluorescent and scanning electron microscopy results. The switch between unicellular and multicellular morphology constitutes an environmentally dependent life cycle that is likely an important step en route to permanent multicellularity.
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Affiliation(s)
- Si Tang
- Institute of General Microbiology, Kiel University, Kiel, Germany
| | - Yuriy Pichugin
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany.
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2
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Liu J, Xing WY, Liu B, Zhang CC. Three-dimensional coordination of cell-division site positioning in a filamentous cyanobacterium. PNAS NEXUS 2022; 2:pgac307. [PMID: 36743469 PMCID: PMC9896137 DOI: 10.1093/pnasnexus/pgac307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/23/2022] [Indexed: 12/26/2022]
Abstract
Bacterial cells mostly divide symmetrically. In the filamentous, multicellular cyanobacterium Anabaena, cell-division planes are aligned vertically relative to the long axis of every single cell. This observation suggests that both the placement and the angle of the division planes are controlled in every single cell so that the filament can grow in one single dimension along the long axis. In this study, we showed that inactivation of patU3 encoding a cell-division inhibitor led cells to divide asymmetrically in two dimensions leading to twisted filaments, indicating that PatU3 controls not only the position but also the angle of the division planes. Deletion of the conserved minC and minD genes affected cell division symmetry, but not the angle of the division planes. Remarkably, when both patU3 and minCD were inactivated, cells could divide asymmetrically over 360° angles in three dimensions across different cellular sections, producing not only cells with irregular sizes, but also branching filaments. This study demonstrated the existence of a system operating in a three-dimensional manner for the control of cell division in Anabaena. Such a regulation may have been evolved to accommodate multicellular behaviors, a hallmark in evolution.
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Affiliation(s)
| | | | - Bowen Liu
- Institut WUT-AMU, Aix-Marseille Université and Wuhan University of Technology, Wuhan, Hubei 430070, People's Republic of China
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3
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Changes in Envelope Structure and Cell–Cell Communication during Akinete Differentiation and Germination in Filamentous Cyanobacterium Trichormus variabilis ATCC 29413. Life (Basel) 2022; 12:life12030429. [PMID: 35330180 PMCID: PMC8953462 DOI: 10.3390/life12030429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/02/2022] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
Planktonic freshwater filamentous cyanobacterium Trichormus variabilis ATCC 29413 (previously known as Anabaena variabilis) can differentiate heterocysts and akinetes to survive under different stress conditions. Whilst heterocysts enable diazotrophic growth, akinetes are spore-like resting cells that make the survival of the species possible under adverse growth conditions. Under suitable environmental conditions, they germinate to produce new vegetative filaments. Several morphological and physiological changes occur during akinete formation and germination. Here, using scanning electron microscopy (SEM), we found that the mature akinetes had a wrinkled envelope, and the surface of the envelope smoothened as the cell size increased during germination. Thereupon, the akinete envelope ruptured to release the short emerging filament. Focused ion beam–scanning electron microscopy (FIB/SEM) tomography of immature akinetes revealed the presence of cytoplasmic granules, presumably consisting of cyanophycin or glycogen. In addition, the akinete envelope architecture of different layers, the exopolysaccharide and glycolipid layers, could be visualized. We found that this multilayered envelope helped to withstand osmotic stress and to maintain the structural integrity. Furthermore, by fluorescence recovery after photobleaching (FRAP) measurements, using the fluorescent tracer calcein, we found that intercellular communication decreased during akinete formation as compared with the vegetative cells. In contrast, freshly germinating filaments restored cell communication.
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4
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MacGregor-Chatwin C, Nürnberg DJ, Jackson PJ, Vasilev C, Hitchcock A, Ho MY, Shen G, Gisriel CJ, Wood WH, Mahbub M, Selinger VM, Johnson MP, Dickman MJ, Rutherford AW, Bryant DA, Hunter CN. Changes in supramolecular organization of cyanobacterial thylakoid membrane complexes in response to far-red light photoacclimation. SCIENCE ADVANCES 2022; 8:eabj4437. [PMID: 35138895 PMCID: PMC8827656 DOI: 10.1126/sciadv.abj4437] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Cyanobacteria are ubiquitous in nature and have developed numerous strategies that allow them to live in a diverse range of environments. Certain cyanobacteria synthesize chlorophylls d and f to acclimate to niches enriched in far-red light (FRL) and incorporate paralogous photosynthetic proteins into their photosynthetic apparatus in a process called FRL-induced photoacclimation (FaRLiP). We characterized the macromolecular changes involved in FRL-driven photosynthesis and used atomic force microscopy to examine the supramolecular organization of photosystem I associated with FaRLiP in three cyanobacterial species. Mass spectrometry showed the changes in the proteome of Chroococcidiopsis thermalis PCC 7203 that accompany FaRLiP. Fluorescence lifetime imaging microscopy and electron microscopy reveal an altered cellular distribution of photosystem complexes and illustrate the cell-to-cell variability of the FaRLiP response.
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Affiliation(s)
| | - Dennis J. Nürnberg
- Department of Life Sciences, Imperial College London, London, UK
- Physics Department, Freie Universität Berlin, Berlin, Germany
| | - Philip J. Jackson
- School of Biosciences, University of Sheffield, Sheffield, UK
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | | | | | - Ming-Yang Ho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Christopher J. Gisriel
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, USA
| | | | - Moontaha Mahbub
- Department of Life Sciences, Imperial College London, London, UK
| | | | | | - Mark J. Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | | | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield, UK
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5
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Kieninger AK, Maldener I. Cell-cell communication through septal junctions in filamentous cyanobacteria. Curr Opin Microbiol 2021; 61:35-41. [PMID: 33676334 DOI: 10.1016/j.mib.2021.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 10/22/2022]
Abstract
Septal junctions are cell-cell connections that mediate intercellular communication in filamentous cyanobacteria. The septal peptidoglycan is perforated by dozens of 20 nm-wide nanopores, through which these proteinaceous structures traverse, physically connecting adjacent cells. On each cytoplasmic side, every septal junction contains a flexible cap structure that closes the connection in a reversible manner upon stress. This gating mechanism reminds of the gap junctions from metazoans and represents a primordial control system for cell-cell communication. In this review, we summarize the knowledge about formation of the nanopore array as the framework for incorporation of cell-cell connecting septal junctions. Furthermore, the architecture of septal junctions, proteins involved in septal junction constitution and regulation of intercellular communication will be addressed.
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Affiliation(s)
- Ann-Katrin Kieninger
- Institute of Microbiology and Infection Medicine, Organismic Interactions, Eberhard Karls University, Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Iris Maldener
- Institute of Microbiology and Infection Medicine, Organismic Interactions, Eberhard Karls University, Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
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6
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Aguilera A, Klemenčič M, Sueldo DJ, Rzymski P, Giannuzzi L, Martin MV. Cell Death in Cyanobacteria: Current Understanding and Recommendations for a Consensus on Its Nomenclature. Front Microbiol 2021; 12:631654. [PMID: 33746925 PMCID: PMC7965980 DOI: 10.3389/fmicb.2021.631654] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/11/2021] [Indexed: 01/31/2023] Open
Abstract
Cyanobacteria are globally widespread photosynthetic prokaryotes and are major contributors to global biogeochemical cycles. One of the most critical processes determining cyanobacterial eco-physiology is cellular death. Evidence supports the existence of controlled cellular demise in cyanobacteria, and various forms of cell death have been described as a response to biotic and abiotic stresses. However, cell death research in this phylogenetic group is a relatively young field and understanding of the underlying mechanisms and molecular machinery underpinning this fundamental process remains largely elusive. Furthermore, no systematic classification of modes of cell death has yet been established for cyanobacteria. In this work, we analyzed the state of knowledge in the field of cyanobacterial cell death. Based on that, we propose unified criterion for the definition of accidental, regulated, and programmed forms of cell death in cyanobacteria based on molecular, biochemical, and morphologic aspects following the directions of the Nomenclature Committee on Cell Death (NCCD). With this, we aim to provide a guide to standardize the nomenclature related to this topic in a precise and consistent manner, which will facilitate further ecological, evolutionary, and applied research in the field of cyanobacterial cell death.
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Affiliation(s)
- Anabella Aguilera
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Kalmar, Sweden
| | - Marina Klemenčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Daniela J. Sueldo
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Piotr Rzymski
- Department of Environmental Medicine, Poznan University of Medical Sciences, Poznan´, Poland
- Integrated Science Association (ISA), Universal Scientific Education and Research Network (USERN), Poznan´, Poland
| | - Leda Giannuzzi
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Universidad Nacional de La Plata, La Plata, Argentina
- Área de Toxicología General, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María Victoria Martin
- Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC-CONICET), Fundación para Investigaciones Biológicas Aplicadas (CIB-FIBA), Mar del Plata, Argentina
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7
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The Ethanologenic Bacterium Zymomonas mobilis Divides Asymmetrically and Exhibits Heterogeneity in DNA Content. Appl Environ Microbiol 2021; 87:AEM.02441-20. [PMID: 33452021 DOI: 10.1128/aem.02441-20] [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: 10/07/2020] [Accepted: 12/23/2020] [Indexed: 02/04/2023] Open
Abstract
The alphaproteobacterium Zymomonas mobilis exhibits extreme ethanologenic physiology, making this species a promising biofuel producer. Numerous studies have investigated its biology relevant to industrial applications and mostly at the population level. However, the organization of single cells in this industrially important polyploid species has been largely uncharacterized. In the present study, we characterized basic cellular behavior of Z. mobilis strain Zm6 under anaerobic conditions at the single-cell level. We observed that growing Z. mobilis cells often divided at a nonmidcell position, which contributed to variant cell size at birth. However, the cell size variance was regulated by a modulation of cell cycle span, mediated by a correlation of bacterial tubulin homologue FtsZ ring accumulation with cell growth. The Z. mobilis culture also exhibited heterogeneous cellular DNA content among individual cells, which might have been caused by asynchronous replication of chromosome that was not coordinated with cell growth. Furthermore, slightly angled divisions might have resulted in temporary curvatures of attached Z. mobilis cells. Overall, the present study uncovers a novel bacterial cell organization in Z. mobilis IMPORTANCE With increasing environmental concerns about the use of fossil fuels, development of a sustainable biofuel production platform has been attracting significant public attention. Ethanologenic Z. mobilis species are endowed with an efficient ethanol fermentation capacity that surpasses, in several respects, that of baker's yeast (Saccharomyces cerevisiae), the most-used microorganism for ethanol production. For development of a Z. mobilis culture-based biorefinery, an investigation of its uncharacterized cell biology is important, because bacterial cellular organization and metabolism are closely associated with each other in a single cell compartment. In addition, the current work demonstrates that the polyploid bacterium Z. mobilis exhibits a distinctive mode of bacterial cell organization, likely reflecting its unique metabolism that does not prioritize incorporation of nutrients for cell growth. Thus, another significant result of this work is to advance our general understanding in the diversity of bacterial cell architecture.
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8
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Springstein BL, Nürnberg DJ, Weiss GL, Pilhofer M, Stucken K. Structural Determinants and Their Role in Cyanobacterial Morphogenesis. Life (Basel) 2020; 10:E355. [PMID: 33348886 PMCID: PMC7766704 DOI: 10.3390/life10120355] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/04/2020] [Accepted: 12/09/2020] [Indexed: 12/16/2022] Open
Abstract
Cells have to erect and sustain an organized and dynamically adaptable structure for an efficient mode of operation that allows drastic morphological changes during cell growth and cell division. These manifold tasks are complied by the so-called cytoskeleton and its associated proteins. In bacteria, FtsZ and MreB, the bacterial homologs to tubulin and actin, respectively, as well as coiled-coil-rich proteins of intermediate filament (IF)-like function to fulfil these tasks. Despite generally being characterized as Gram-negative, cyanobacteria have a remarkably thick peptidoglycan layer and possess Gram-positive-specific cell division proteins such as SepF and DivIVA-like proteins, besides Gram-negative and cyanobacterial-specific cell division proteins like MinE, SepI, ZipN (Ftn2) and ZipS (Ftn6). The diversity of cellular morphologies and cell growth strategies in cyanobacteria could therefore be the result of additional unidentified structural determinants such as cytoskeletal proteins. In this article, we review the current advances in the understanding of the cyanobacterial cell shape, cell division and cell growth.
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Affiliation(s)
- Benjamin L. Springstein
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Dennis J. Nürnberg
- Department of Physics, Biophysics and Biochemistry of Photosynthetic Organisms, Freie Universität Berlin, 14195 Berlin, Germany;
| | - Gregor L. Weiss
- Department of Biology, Institute of Molecular Biology & Biophysics, ETH Zürich, 8092 Zürich, Switzerland; (G.L.W.); (M.P.)
| | - Martin Pilhofer
- Department of Biology, Institute of Molecular Biology & Biophysics, ETH Zürich, 8092 Zürich, Switzerland; (G.L.W.); (M.P.)
| | - Karina Stucken
- Department of Food Engineering, Universidad de La Serena, La Serena 1720010, Chile;
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Inactivation of Three RG(S/T)GR Pentapeptide-Containing Negative Regulators of HetR Results in Lethal Differentiation of Anabaena PCC 7120. Life (Basel) 2020; 10:life10120326. [PMID: 33291589 PMCID: PMC7761841 DOI: 10.3390/life10120326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 12/19/2022] Open
Abstract
The filamentous cyanobacterium Anabaena sp. PCC 7120 produces, during the differentiation of heterocysts, a short peptide PatS and a protein HetN, both containing an RGSGR pentapeptide essential for activity. Both act on the master regulator HetR to guide heterocyst pattern formation by controlling the binding of HetR to DNA and its turnover. A third small protein, PatX, with an RG(S/T)GR motif is present in all HetR-containing cyanobacteria. In a nitrogen-depleted medium, inactivation of patX does not produce a discernible change in phenotype, but its overexpression blocks heterocyst formation. Mutational analysis revealed that PatX is not required for normal intercellular signaling, but it nonetheless is required when PatS is absent to prevent rapid ectopic differentiation. Deprivation of all three negative regulators—PatS, PatX, and HetN—resulted in synchronous differentiation. However, in a nitrogen-containing medium, such deprivation leads to extensive fragmentation, cell lysis, and aberrant differentiation, while either PatX or PatS as the sole HetR regulator can establish and maintain a semiregular heterocyst pattern. These results suggest that tight control over HetR by PatS and PatX is needed to sustain vegetative growth and regulated development. The mutational analysis has been interpreted in light of the opposing roles of negative regulators of HetR and the positive regulator HetL.
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Hammerschmidt K, Landan G, Domingues Kümmel Tria F, Alcorta J, Dagan T. The Order of Trait Emergence in the Evolution of Cyanobacterial Multicellularity. Genome Biol Evol 2020; 13:5999801. [PMID: 33231627 PMCID: PMC7937182 DOI: 10.1093/gbe/evaa249] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 01/31/2023] Open
Abstract
The transition from unicellular to multicellular organisms is one of the most significant events in the history of life. Key to this process is the emergence of Darwinian individuality at the higher level: Groups must become single entities capable of reproduction for selection to shape their evolution. Evolutionary transitions in individuality are characterized by cooperation between the lower level entities and by division of labor. Theory suggests that division of labor may drive the transition to multicellularity by eliminating the trade off between two incompatible processes that cannot be performed simultaneously in one cell. Here, we examine the evolution of the most ancient multicellular transition known today, that of cyanobacteria, where we reconstruct the sequence of ecological and phenotypic trait evolution. Our results show that the prime driver of multicellularity in cyanobacteria was the expansion in metabolic capacity offered by nitrogen fixation, which was accompanied by the emergence of the filamentous morphology and succeeded by a reproductive life cycle. This was followed by the progression of multicellularity into higher complexity in the form of differentiated cells and patterned multicellularity.
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Affiliation(s)
- Katrin Hammerschmidt
- Genomic Microbiology Group, Institute of Microbiology, Kiel University, Germany,Corresponding author: E-mail:
| | - Giddy Landan
- Genomic Microbiology Group, Institute of Microbiology, Kiel University, Germany
| | | | - Jaime Alcorta
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago, Chile
| | - Tal Dagan
- Genomic Microbiology Group, Institute of Microbiology, Kiel University, Germany
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11
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Springstein BL, Weissenbach J, Koch R, Stücker F, Stucken K. The role of the cytoskeletal proteins MreB and FtsZ in multicellular cyanobacteria. FEBS Open Bio 2020; 10:2510-2531. [PMID: 33112491 PMCID: PMC7714070 DOI: 10.1002/2211-5463.13016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/17/2020] [Accepted: 10/26/2020] [Indexed: 01/28/2023] Open
Abstract
Multiseriate and true‐branching cyanobacteria are at the peak of prokaryotic morphological complexity. However, little is known about the mechanisms governing multiplanar cell division and morphogenesis. Here, we study the function of the prokaryotic cytoskeletal proteins, MreB and FtsZ in Fischerella muscicola PCC 7414 and Chlorogloeopsis fritschii PCC 6912. Vancomycin and HADA labeling revealed a mixed apical, septal, and lateral trichome growth mode in F. muscicola, whereas C. fritschii exhibits septal growth. In all morphotypes from both species, MreB forms either linear filaments or filamentous strings and can interact with FtsZ. Furthermore, multiplanar cell division in F. muscicola likely depends on FtsZ dosage. Our results lay the groundwork for future studies on cytoskeletal proteins in morphologically complex cyanobacteria.
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Affiliation(s)
| | - Julia Weissenbach
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Germany
| | - Robin Koch
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Germany
| | - Fenna Stücker
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Germany
| | - Karina Stucken
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Germany
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12
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Global distribution of a chlorophyll f cyanobacterial marker. ISME JOURNAL 2020; 14:2275-2287. [PMID: 32457503 PMCID: PMC7608106 DOI: 10.1038/s41396-020-0670-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 04/16/2020] [Accepted: 04/28/2020] [Indexed: 02/04/2023]
Abstract
Some cyanobacteria use light outside the visible spectrum for oxygenic photosynthesis. The far-red light (FRL) region is made accessible through a complex acclimation process that involves the formation of new phycobilisomes and photosystems containing chlorophyll f. Diverse cyanobacteria ranging from unicellular to branched-filamentous forms show this response. These organisms have been isolated from shaded environments such as microbial mats, soil, rock, and stromatolites. However, the full spread of chlorophyll f-containing species in nature is still unknown. Currently, discovering new chlorophyll f cyanobacteria involves lengthy incubation times under selective far-red light. We have used a marker gene to detect chlorophyll f organisms in environmental samples and metagenomic data. This marker, apcE2, encodes a phycobilisome linker associated with FRL-photosynthesis. By focusing on a far-red motif within the sequence, degenerate PCR and BLAST searches can effectively discriminate against the normal chlorophyll a-associated apcE. Even short recovered sequences carry enough information for phylogenetic placement. Markers of chlorophyll f photosynthesis were found in metagenomic datasets from diverse environments around the globe, including cyanobacterial symbionts, hypersaline lakes, corals, and the Arctic/Antarctic regions. This additional information enabled higher phylogenetic resolution supporting the hypothesis that vertical descent, as opposed to horizontal gene transfer, is largely responsible for this phenotype’s distribution.
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13
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Alcorta J, Vergara-Barros P, Antonaru LA, Alcamán-Arias ME, Nürnberg DJ, Díez B. Fischerella thermalis: a model organism to study thermophilic diazotrophy, photosynthesis and multicellularity in cyanobacteria. Extremophiles 2019; 23:635-647. [PMID: 31512055 DOI: 10.1007/s00792-019-01125-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 08/05/2019] [Indexed: 01/19/2023]
Abstract
The true-branching cyanobacterium Fischerella thermalis (also known as Mastigocladus laminosus) is widely distributed in hot springs around the world. Morphologically, it has been described as early as 1837. However, its taxonomic placement remains controversial. F. thermalis belongs to the same genus as mesophilic Fischerella species but forms a monophyletic clade of thermophilic Fischerella strains and sequences from hot springs. Their recent divergence from freshwater or soil true-branching species and the ongoing process of specialization inside the thermal gradient make them an interesting evolutionary model to study. F. thermalis is one of the most complex prokaryotes. It forms a cellular network in which the main trichome and branches exchange metabolites and regulators via septal junctions. This species can adapt to a variety of environmental conditions, with its photosynthetic apparatus remaining active in a temperature range from 15 to 58 °C. Together with its nitrogen-fixing ability, this allows it to dominate in hot spring microbial mats and contribute significantly to the de novo carbon and nitrogen input. Here, we review the current knowledge on the taxonomy and distribution of F. thermalis, its morphological complexity, and its physiological adaptations to an extreme environment.
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Affiliation(s)
- Jaime Alcorta
- Department of Molecular Genetics and Microbiology, Pontifical Catholic University of Chile, Avenida Libertador Bernardo O'higgins 340, Casilla 144-D, C.P. 651, 3677, Santiago, Chile
| | - Pablo Vergara-Barros
- Department of Molecular Genetics and Microbiology, Pontifical Catholic University of Chile, Avenida Libertador Bernardo O'higgins 340, Casilla 144-D, C.P. 651, 3677, Santiago, Chile
| | - Laura A Antonaru
- Department of Life Science, Imperial College, London, SW7 2AZ, UK
| | - María E Alcamán-Arias
- Department of Molecular Genetics and Microbiology, Pontifical Catholic University of Chile, Avenida Libertador Bernardo O'higgins 340, Casilla 144-D, C.P. 651, 3677, Santiago, Chile.,Department of Oceanography, University of Concepcion, Concepción, Chile.,Center for Climate and Resilience Research (CR)2, Santiago, Chile
| | - Dennis J Nürnberg
- Department of Life Science, Imperial College, London, SW7 2AZ, UK.,Physics Department, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Beatriz Díez
- Department of Molecular Genetics and Microbiology, Pontifical Catholic University of Chile, Avenida Libertador Bernardo O'higgins 340, Casilla 144-D, C.P. 651, 3677, Santiago, Chile. .,Center for Climate and Resilience Research (CR)2, Santiago, Chile.
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14
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Noreña-Caro D, Benton MG. Cyanobacteria as photoautotrophic biofactories of high-value chemicals. J CO2 UTIL 2018. [DOI: 10.1016/j.jcou.2018.10.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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15
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Elhai J, Khudyakov I. Ancient association of cyanobacterial multicellularity with the regulator HetR and an RGSGR pentapeptide-containing protein (PatX). Mol Microbiol 2018; 110:931-954. [PMID: 29885033 DOI: 10.1111/mmi.14003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2018] [Indexed: 12/14/2022]
Abstract
One simple model to explain biological pattern postulates the existence of a stationary regulator of differentiation that positively affects its own expression, coupled with a diffusible suppressor of differentiation that inhibits the regulator's expression. The first has been identified in the filamentous, heterocyst-forming cyanobacterium, Anabaena PCC 7120 as the transcriptional regulator, HetR and the second as the small protein, PatS, which contains a critical RGSGR motif that binds to HetR. HetR is present in almost all filamentous cyanobacteria, but only a subset of heterocyst-forming strains carry proteins similar to PatS. We identified a third protein, PatX that also carries the RGSGR motif and is coextensive with HetR. Amino acid sequences of PatX contain two conserved regions: the RGSGR motif and a hydrophobic N-terminus. Within 69 nt upstream from all instances of the gene is a DIF1 motif correlated in Anabaena with promoter induction in developing heterocysts, preceded in heterocyst-forming strains by an apparent NtcA-binding site, associated with regulation by nitrogen-status. Consistent with a role in the simple model, PatX is expressed dependent on HetR and acts to inhibit differentiation. The acquisition of the PatX/HetR pair preceded the appearance of both PatS and heterocysts, dating back to the beginnings of multicellularity.
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Affiliation(s)
- Jeff Elhai
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Ivan Khudyakov
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, 196608, Russia
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Temperature modulates Fischerella thermalis ecotypes in Porcelana Hot Spring. Syst Appl Microbiol 2018; 41:531-543. [PMID: 30041921 DOI: 10.1016/j.syapm.2018.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 05/18/2018] [Accepted: 05/23/2018] [Indexed: 11/21/2022]
Abstract
In the Porcelana Hot Spring (Northern Patagonia), true-branching cyanobacteria are the dominant primary producers in microbial mats, and they are mainly responsible for carbon and nitrogen fixation. However, little is known about their metabolic and genomic adaptations at high temperatures. Therefore, in this study, a total of 81 Fischerella thermalis strains (also known as Mastigocladus laminosus) were isolated from mat samples in a thermal gradient between 61-46°C. The complementary use of proteomic comparisons from these strains, and comparative genomics of F. thermalis pangenomes, suggested that at least two different ecotypes were present within these populations. MALDI-TOF MS analysis separated the strains into three clusters; two with strains obtained from mats within the upper temperature range (61 and 54°C), and a third obtained from mats within the lower temperature range (51 and 46°C). Both groups possessed different but synonymous nifH alleles. The main proteomic differences were associated with the abundance of photosynthesis-related proteins. Three F. thermalis metagenome assembled genomes (MAGs) were described from 66, 58 and 48°C metagenomes. These pangenomes indicated a divergence of orthologous genes and a high abundance of exclusive genes at 66°C. These results improved the current understanding of thermal adaptation of F. thermalis and the evolution of these thermophilic cyanobacterial species.
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Bornikoel J, Staiger J, Madlung J, Forchhammer K, Maldener I. LytM factor Alr3353 affects filament morphology and cell-cell communication in the multicellular cyanobacteriumAnabaenasp. PCC 7120. Mol Microbiol 2018; 108:187-203. [DOI: 10.1111/mmi.13929] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 01/16/2023]
Affiliation(s)
- Jan Bornikoel
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
| | - Julia Staiger
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
| | - Johannes Madlung
- Proteome Center Tübingen; University of Tübingen, Auf der Morgenstelle 15; 72076 Tübingen Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
| | - Iris Maldener
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
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Raven JA. Evolution and palaeophysiology of the vascular system and other means of long-distance transport. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160497. [PMID: 29254962 PMCID: PMC5745333 DOI: 10.1098/rstb.2016.0497] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2017] [Indexed: 12/13/2022] Open
Abstract
Photolithotrophic growth on land using atmospheric CO2 inevitably involves H2O vapour loss. Embryophytes greater than or equal to 100 mm tall are homoiohydric and endohydric with mass flow of aqueous solution through the xylem in tracheophytes. Structural details in Rhynie sporophytes enable modelling of the hydraulics of H2O supply to the transpiring surface, and the potential for gas exchange with the Devonian atmosphere. Xylem carrying H2O under tension involves programmed cell death, rigid cell walls and embolism repair; fossils provide little evidence on these functions other than the presence of lignin. The phenylalanine ammonia lyase essential for lignin synthesis came from horizontal gene transfer. Rhynie plants lack endodermes, limiting regulation of the supply of soil nutrients to shoots. The transfer of organic solutes from photosynthetic sites to growing and storage tissues involves mass flow through phloem in extant tracheophytes. Rhynie plants show little evidence of phloem; possible alternatives for transport of organic solutes are discussed. Extant examples of the arbuscular mycorrhizas found in Rhynie plants exchange soil-derived nutrients (especially P) for plant-derived organic matter, involving bidirectional mass flow along the hyphae. The aquatic cyanobacteria and the charalean Palaeonitella at Rhynie also have long-distance (relative to the size of the organism) transport.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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Bornikoel J, Carrión A, Fan Q, Flores E, Forchhammer K, Mariscal V, Mullineaux CW, Perez R, Silber N, Wolk CP, Maldener I. Role of Two Cell Wall Amidases in Septal Junction and Nanopore Formation in the Multicellular Cyanobacterium Anabaena sp. PCC 7120. Front Cell Infect Microbiol 2017; 7:386. [PMID: 28929086 PMCID: PMC5591844 DOI: 10.3389/fcimb.2017.00386] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 08/15/2017] [Indexed: 01/11/2023] Open
Abstract
Filamentous cyanobacteria have developed a strategy to perform incompatible processes in one filament by differentiating specialized cell types, N2-fixing heterocysts and CO2-fixing, photosynthetic, vegetative cells. These bacteria can be considered true multicellular organisms with cells exchanging metabolites and signaling molecules via septal junctions, involving the SepJ and FraCD proteins. Previously, it was shown that the cell wall lytic N-acetylmuramyl-L-alanine amidase, AmiC2, is essential for cell-cell communication in Nostoc punctiforme. This enzyme perforates the septal peptidoglycan creating an array of nanopores, which may be the framework for septal junction complexes. In Anabaena sp. PCC 7120, two homologs of AmiC2, encoded by amiC1 and amiC2, were identified and investigated in two different studies. Here, we compare the function of both AmiC proteins by characterizing different Anabaena amiC mutants, which was not possible in N. punctiforme, because there the amiC1 gene could not be inactivated. This study shows the different impact of each protein on nanopore array formation, the process of cell-cell communication, septal protein localization, and heterocyst differentiation. Inactivation of either amidase resulted in significant reduction in nanopore count and in the rate of fluorescent tracer exchange between neighboring cells measured by FRAP analysis. In an amiC1 amiC2 double mutant, filament morphology was affected and heterocyst differentiation was abolished. Furthermore, the inactivation of amiC1 influenced SepJ localization and prevented the filament-fragmentation phenotype that is characteristic of sepJ or fraC fraD mutants. Our findings suggest that both amidases are to some extent redundant in their function, and describe a functional relationship of AmiC1 and septal proteins SepJ and FraCD.
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Affiliation(s)
- Jan Bornikoel
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions, University of TübingenTübingen, Germany
| | - Alejandro Carrión
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | - Qing Fan
- Department of Microbiology-Immunology, Feinberg School of Medicine of Northwestern UniversityChicago, IL, United States
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions, University of TübingenTübingen, Germany
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of LondonLondon, United Kingdom
| | - Rebeca Perez
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions, University of TübingenTübingen, Germany
| | - Nadine Silber
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions, University of TübingenTübingen, Germany
| | - C Peter Wolk
- MSU-DOE Plant Research Laboratory and Department of Plant Biology, Michigan State UniversityEast Lansing, MI, United States
| | - Iris Maldener
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions, University of TübingenTübingen, Germany
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Antonaru LA, Nürnberg DJ. Role of PatS and cell type on the heterocyst spacing pattern in a filamentous branching cyanobacterium. FEMS Microbiol Lett 2017; 364:3983256. [PMID: 28859320 PMCID: PMC5812504 DOI: 10.1093/femsle/fnx154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/19/2017] [Indexed: 12/16/2022] Open
Abstract
Cell differentiation is one of the marks of multicellular organisms. Terminally specialised nitrogen-fixing cells, termed heterocysts, evolved in filamentous cyanobacteria more than 2 Gya. The development of their spacing pattern has been thoroughly investigated in model organisms such as Anabaena sp. PCC 7120. This paper focuses on the more complex, branching cyanobacterium Mastigocladus laminosus (Stigonematales). Contrary to what has been previously published, a heterocyst spacing pattern is present in M. laminosus but it varies with the age of the culture and the morphology of the cells. Heterocysts in young, narrow trichomes were more widely spaced (∼14.8 cells) than those in old, wide trichomes (∼9.4 cells). Biochemical and transgenic experiments reveal that the heterocyst spacing pattern is affected by the heterocyst inhibitor PatS. Addition of the pentapeptide RGSGR (PatS-5) to the growth medium and overexpression of patS from Anabaena sp. PCC 7120 in M. laminosus resulted in the loss of heterocyst differentiation under nitrogen deprivation. Bioinformatics investigations indicated that putative PatS sequences within cyanobacteria are highly diverse, and fall into two main clades. Both are present in most branching cyanobacteria. Despite its more complex, branching phenotype, M. laminosus appears to use a PatS-based pathway for heterocyst differentiation, a property shared by Anabaena/Nostoc.
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Herrero A, Stavans J, Flores E. The multicellular nature of filamentous heterocyst-forming cyanobacteria. FEMS Microbiol Rev 2016; 40:831-854. [DOI: 10.1093/femsre/fuw029] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/10/2016] [Accepted: 07/09/2016] [Indexed: 11/13/2022] Open
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Mariscal V, Nürnberg DJ, Herrero A, Mullineaux CW, Flores E. Overexpression of SepJ alters septal morphology and heterocyst pattern regulated by diffusible signals in Anabaena. Mol Microbiol 2016; 101:968-81. [PMID: 27273832 DOI: 10.1111/mmi.13436] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/02/2016] [Indexed: 01/08/2023]
Abstract
Filamentous, N2 -fixing, heterocyst-forming cyanobacteria grow as chains of cells that are connected by septal junctions. In the model organism Anabaena sp. strain PCC 7120, the septal protein SepJ is required for filament integrity, normal intercellular molecular exchange, heterocyst differentiation, and diazotrophic growth. An Anabaena strain overexpressing SepJ made wider septa between vegetative cells than the wild type, which correlated with a more spread location of SepJ in the septa as observed with a SepJ-GFP fusion, and contained an increased number of nanopores, the septal peptidoglycan perforations that likely accommodate septal junctions. The septa between heterocysts and vegetative cells, which are narrow in wild-type Anabaena, were notably enlarged in the SepJ-overexpressing mutant. Intercellular molecular exchange tested with fluorescent tracers was increased for the SepJ-overexpressing strain specifically in the case of calcein transfer between vegetative cells and heterocysts. These results support an association between calcein transfer, SepJ-related septal junctions, and septal peptidoglycan nanopores. Under nitrogen deprivation, the SepJ-overexpressing strain produced an increased number of contiguous heterocysts but a decreased percentage of total heterocysts. These effects were lost or altered in patS and hetN mutant backgrounds, supporting a role of SepJ in the intercellular transfer of regulatory signals for heterocyst differentiation.
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Affiliation(s)
- Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, Seville, E-41092, Spain
| | - Dennis J Nürnberg
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, Seville, E-41092, Spain
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, Seville, E-41092, Spain.
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Mandakovic D, Trigo C, Andrade D, Riquelme B, Gómez-Lillo G, Soto-Liebe K, Díez B, Vásquez M. CyDiv, a Conserved and Novel Filamentous Cyanobacterial Cell Division Protein Involved in Septum Localization. Front Microbiol 2016; 7:94. [PMID: 26903973 PMCID: PMC4748335 DOI: 10.3389/fmicb.2016.00094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/18/2016] [Indexed: 11/13/2022] Open
Abstract
Cell division in bacteria has been studied mostly in Escherichia coli and Bacillus subtilis, model organisms for Gram-negative and Gram-positive bacteria, respectively. However, cell division in filamentous cyanobacteria is poorly understood. Here, we identified a novel protein, named CyDiv (Cyanobacterial Division), encoded by the all2320 gene in Anabaena sp. PCC 7120. We show that CyDiv plays a key role during cell division. CyDiv has been previously described only as an exclusive and conserved hypothetical protein in filamentous cyanobacteria. Using polyclonal antibodies against CyDiv, we showed that it localizes at different positions depending on cell division timing: poles, septum, in both daughter cells, but also in only one of the daughter cells. The partial deletion of CyDiv gene generates partial defects in cell division, including severe membrane instability and anomalous septum localization during late division. The inability to complete knock out CyDiv strains suggests that it is an essential gene. In silico structural protein analyses and our experimental results suggest that CyDiv is an FtsB/DivIC-like protein, and could therefore, be part of an essential late divisome complex in Anabaena sp. PCC 7120.
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Affiliation(s)
- Dinka Mandakovic
- Fondap Center for Genome Regulation, Universidad de ChileSantiago, Chile; Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de ChileSantiago, Chile
| | - Carla Trigo
- Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Derly Andrade
- Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Brenda Riquelme
- Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Gabriela Gómez-Lillo
- Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Katia Soto-Liebe
- Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Beatriz Díez
- Laboratorio de Ecología Microbiana de Sistemas Extremos, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Mónica Vásquez
- Laboratorio de Ecología Microbiana y Toxicología Ambiental, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile Santiago, Chile
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Wilde A, Mullineaux CW. Motility in cyanobacteria: polysaccharide tracks and Type IV pilus motors. Mol Microbiol 2015; 98:998-1001. [PMID: 26447922 DOI: 10.1111/mmi.13242] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 01/09/2023]
Abstract
Motility in cyanobacteria is useful for purposes that range from seeking out favourable light environments to establishing symbioses with plants and fungi. No known cyanobacterium is equipped with flagella, but a diverse range of species is able to 'glide' or 'twitch' across surfaces. Cyanobacteria with this capacity range from unicellular species to complex filamentous forms, including species such as Nostoc punctiforme, which can generate specialised motile filaments called hormogonia. Recent work on the model unicellular cyanobacterium Synechocystis sp. PCC 6803 has shown that its means of propulsion has much in common with the twitching motility of heterotrophs such as Pseudomonas and Myxococcus. Movement depends on Type IV pili, which are extended, adhere to the substrate and then retract to pull the cell across the surface. Previous work on filamentous cyanobacteria suggested a very different mechanism, with movement powered by the directional extrusion of polysaccharide from pores close to the cell junctions. Now a new report by Khayatan and colleagues in this issue of Molecular Microbiology suggests that the motility of Nostoc hormogonia has much more in common with Synechocystis than was previously thought. In both cases, polysaccharide secretion is important for preparing the surface, but the directional motive force comes from Type IV pili.
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Affiliation(s)
- Annegret Wilde
- Institute of Biology III, University of Freiburg, D79104, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
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Requirement of Fra proteins for communication channels between cells in the filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120. Proc Natl Acad Sci U S A 2015. [PMID: 26216997 DOI: 10.1073/pnas.1512232112] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 differentiates specialized cells, heterocysts, that fix atmospheric nitrogen and transfer the fixed nitrogen to adjacent vegetative cells. Reciprocally, vegetative cells transfer fixed carbon to heterocysts. Several routes have been described for metabolite exchange within the filament, one of which involves communicating channels that penetrate the septum between adjacent cells. Several fra gene mutants were isolated 25 y ago on the basis of their phenotypes: inability to fix nitrogen and fragmentation of filaments upon transfer from N+ to N- media. Cryopreservation combined with electron tomography were used to investigate the role of three fra gene products in channel formation. FraC and FraG are clearly involved in channel formation, whereas FraD has a minor part. Additionally, FraG was located close to the cytoplasmic membrane and in the heterocyst neck, using immunogold labeling with antibody raised to the N-terminal domain of the FraG protein.
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Nürnberg DJ, Mariscal V, Bornikoel J, Nieves-Morión M, Krauß N, Herrero A, Maldener I, Flores E, Mullineaux CW. Intercellular diffusion of a fluorescent sucrose analog via the septal junctions in a filamentous cyanobacterium. mBio 2015; 6:e02109. [PMID: 25784700 PMCID: PMC4453526 DOI: 10.1128/mbio.02109-14] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/11/2015] [Indexed: 11/24/2022] Open
Abstract
UNLABELLED Many filamentous cyanobacteria produce specialized nitrogen-fixing cells called heterocysts, which are located at semiregular intervals along the filament with about 10 to 20 photosynthetic vegetative cells in between. Nitrogen fixation in these complex multicellular bacteria depends on metabolite exchange between the two cell types, with the heterocysts supplying combined-nitrogen compounds but dependent on the vegetative cells for photosynthetically produced carbon compounds. Here, we used a fluorescent tracer to probe intercellular metabolite exchange in the filamentous heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. We show that esculin, a fluorescent sucrose analog, is incorporated by a sucrose import system into the cytoplasm of Anabaena cells. The cytoplasmic esculin is rapidly and reversibly exchanged across vegetative-vegetative and vegetative-heterocyst cell junctions. Our measurements reveal the kinetics of esculin exchange and also show that intercellular metabolic communication is lost in a significant fraction of older heterocysts. SepJ, FraC, and FraD are proteins located at the intercellular septa and are suggested to form structures analogous to gap junctions. We show that a ΔsepJ ΔfraC ΔfraD triple mutant shows an altered septum structure with thinner septa but a denser peptidoglycan layer. Intercellular diffusion of esculin and fluorescein derivatives is impaired in this mutant, which also shows a greatly reduced frequency of nanopores in the intercellular septal cross walls. These findings suggest that FraC, FraD, and SepJ are important for the formation of junctional structures that constitute the major pathway for feeding heterocysts with sucrose. IMPORTANCE Anabaena and its relatives are filamentous cyanobacteria that exhibit a sophisticated form of prokaryotic multicellularity, with the formation of differentiated cell types, including normal photosynthetic cells and specialized nitrogen-fixing cells called heterocysts. The question of how heterocysts communicate and exchange metabolites with other cells in the filament is key to understanding this form of bacterial multicellularity. Here we provide the first information on the intercellular exchange of a physiologically important molecule, sucrose. We show that a fluorescent sucrose analog can be imported into the Anabaena cytoplasm by a sucrose import system. Once in the cytoplasm, it is rapidly and reversibly exchanged among all of the cells in the filament by diffusion across the septal junctions. Photosynthetically produced sucrose likely follows the same route from cytoplasm to cytoplasm. We identify some of the septal proteins involved in sucrose exchange, and our results indicate that these proteins form structures functionally analogous to metazoan gap junctions.
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Affiliation(s)
- Dennis J Nürnberg
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Seville, Spain
| | - Jan Bornikoel
- Department of Microbiology/Organismic Interactions, University of Tübingen, Tübingen, Germany
| | - Mercedes Nieves-Morión
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Seville, Spain
| | - Norbert Krauß
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Seville, Spain
| | - Iris Maldener
- Department of Microbiology/Organismic Interactions, University of Tübingen, Tübingen, Germany
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Seville, Spain
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
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Ramos-León F, Mariscal V, Frías JE, Flores E, Herrero A. Divisome-dependent subcellular localization of cell-cell joining protein SepJ in the filamentous cyanobacterium Anabaena. Mol Microbiol 2015; 96:566-80. [PMID: 25644579 DOI: 10.1111/mmi.12956] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2015] [Indexed: 12/15/2022]
Abstract
Heterocyst-forming cyanobacteria are multicellular organisms that grow as filaments that can be hundreds of cells long. Septal junction complexes, of which SepJ is a possible component, appear to join the cells in the filament. SepJ is a cytoplasmic membrane protein that contains a long predicted periplasmic section and localizes not only to the cell poles in the intercellular septa but also to a position similar to a Z ring when cell division starts suggesting a relation with the divisome. Here, we created a mutant of Anabaena sp. strain PCC 7120 in which the essential divisome gene ftsZ is expressed from a synthetic NtcA-dependent promoter, whose activity depends on the nitrogen source. In the presence of ammonium, low levels of FtsZ were produced, and the subcellular localization of SepJ, which was investigated by immunofluorescence, was impaired. Possible interactions of SepJ with itself and with divisome proteins FtsZ, FtsQ and FtsW were investigated using the bacterial two-hybrid system. We found SepJ self-interaction and a specific interaction with FtsQ, confirmed by co-purification and involving parts of the SepJ and FtsQ periplasmic sections. Therefore, SepJ can form multimers, and in Anabaena, the divisome has a role beyond cell division, localizing a septal protein essential for multicellularity.
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Affiliation(s)
- Félix Ramos-León
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, E-41092, Seville, Spain
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Klemke F, Beyer G, Sawade L, Saitov A, Korte T, Maldener I, Lockau W, Nürnberg DJ, Volkmer T. All1371 is a polyphosphate-dependent glucokinase in Anabaena sp. PCC 7120. MICROBIOLOGY (READING, ENGLAND) 2014; 160:2807-2819. [PMID: 25320362 PMCID: PMC4252912 DOI: 10.1099/mic.0.081836-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/09/2014] [Indexed: 11/18/2022]
Abstract
The polyphosphate glucokinases can phosphorylate glucose to glucose 6-phosphate using polyphosphate as the substrate. ORF all1371 encodes a putative polyphosphate glucokinase in the filamentous heterocyst-forming cyanobacterium Anabaena sp. PCC 7120. Here, ORF all1371 was heterologously expressed in Escherichia coli, and its purified product was characterized. Enzyme activity assays revealed that All1371 is an active polyphosphate glucokinase that can phosphorylate both glucose and mannose in the presence of divalent cations in vitro. Unlike many other polyphosphate glucokinases, for which nucleoside triphosphates (e.g. ATP or GTP) act as phosphoryl group donors, All1371 required polyphosphate to confer its enzymic activity. The enzymic reaction catalysed by All1371 followed classical Michaelis-Menten kinetics, with kcat = 48.2 s(-1) at pH 7.5 and 28 °C and KM = 1.76 µM and 0.118 mM for polyphosphate and glucose, respectively. Its reaction mechanism was identified as a particular multi-substrate mechanism called the 'bi-bi ping-pong mechanism'. Bioinformatic analyses revealed numerous polyphosphate-dependent glucokinases in heterocyst-forming cyanobacteria. Viability of an Anabaena sp. PCC 7120 mutant strain lacking all1371 was impaired under nitrogen-fixing conditions. GFP promoter studies indicate expression of all1371 under combined nitrogen deprivation. All1371 might play a substantial role in Anabaena sp. PCC 7120 under these conditions.
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Affiliation(s)
| | - Gabriele Beyer
- Plant Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Linda Sawade
- Plant Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ali Saitov
- Plant Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Thomas Korte
- Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Iris Maldener
- Institute of Microbiology and Infection Medicine/Organismic Interactions, University of Tübingen, Tübingen, Germany
| | - Wolfgang Lockau
- Plant Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dennis J Nürnberg
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Thomas Volkmer
- Plant Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany
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Mullineaux CW, Nürnberg DJ. Tracing the path of a prokaryotic paracrine signal. Mol Microbiol 2014; 94:1208-12. [DOI: 10.1111/mmi.12851] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Conrad W. Mullineaux
- School of Biological and Chemical SciencesQueen Mary University of London Mile End Road London E1 4NS UK
- Freiburg Institute for Advanced Studies (FRIAS)University of Freiburg Freiburg Germany
| | - Dennis J. Nürnberg
- School of Biological and Chemical SciencesQueen Mary University of London Mile End Road London E1 4NS UK
- Department of Life SciencesImperial College London London SW7 2AZ UK
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Nürnberg D, Mastroianni G, Mullineaux C, McPhail G. Visualization of Cell Complexity in the Filamentous Cyanobacterium Mastigocladus laminosus by Transmission Electron Microscopy (TEM). Bio Protoc 2014. [DOI: 10.21769/bioprotoc.1305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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