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Uesaka K, Banba M, Chiba S, Fujita Y. Restoration of the Functional nif Gene Cluster by Complex Recombination Events during Heterocyst Development in the Nitrogen-Fixing Cyanobacterium Calothrix sp. NIES-4101. Plant Cell Physiol 2024:pcae011. [PMID: 38305573 DOI: 10.1093/pcp/pcae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/17/2024] [Accepted: 02/01/2024] [Indexed: 02/03/2024]
Abstract
In the genome of the heterocystous cyanobacterium Calothrix sp. NIES-4101 (NIES-4101), the four genes essential for nitrogen fixation (nifB, nifH, nifD, and nifK) are highly fragmented into 13 parts in a 350-kb chromosomal region, and four of these parts are encoded in the reverse strand. Such a complex fragmentation feature makes it difficult to restore the intact nifBHDK genes by the excision mechanism found in the nifD gene of the Anabaena sp. PCC 7120 heterocyst. To examine the nitrogen-fixing ability of NIES-4101, we confirmed that NIES-4101 grew well on combined nitrogen-free medium and showed high nitrogenase activity, which strongly suggested that the complete nifBHDK genes are restored by a complex recombination process in heterocysts. Next, we resequenced the genome prepared from cells grown under nitrogen-fixing conditions. Two contigs covering the complete nifHDK and nifB genes were found by de novo assembly of the sequencing reads. In addition, DNA fragments covering the nifBHDK operon were successfully amplified by PCR. We propose that the process of nifBHDK restoration occurs as follows. First, the nifD-nifK genes are restored by four excision events. Then the complete nifH and nifB genes are restored by two excision events followed by two successive inversion events between the inverted repeat sequences and one excision event, forming the functional nif gene cluster, nifB-fdxN-nifS-nifU-nifH-nifD-nifK. All genes coding recombinases responsible for these nine recombination events are located close to the terminal repeat sequences. The restoration of the nifBHDK genes in NIES-4101 is the most complex genome reorganization reported in heterocystous cyanobacteria.
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Affiliation(s)
- Kazuma Uesaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601
| | - Mari Banba
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601
| | - Sotaro Chiba
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601
| | - Yuichi Fujita
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601
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Doppler P, Kriechbaum R, Spadiut O. High-throughput characterization of the filamentous cyanobacterium Anabaena sp. using flow cytometry. J Microbiol Methods 2022; 199:106510. [PMID: 35697185 DOI: 10.1016/j.mimet.2022.106510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 06/06/2022] [Accepted: 06/06/2022] [Indexed: 12/27/2022]
Abstract
In stirred-tank photobioreactors agitation causes fragmentation of filamentous cyanobacteria. Here, we introduce a flow cytometric approach for high-throughput measurements of trichome dimensions, heterocysts and metabolic activity of Anabaena sp. cultures. The longest characterized trichome had 1135 μm chain length. This technology could potentially be used for monitoring and control purposes.
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Affiliation(s)
- Philipp Doppler
- Research Division Biochemical Engineering, Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria.
| | - Ricarda Kriechbaum
- Research Division Biochemical Engineering, Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria.
| | - Oliver Spadiut
- Research Division Biochemical Engineering, Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria.
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Walter J, Leganés F, Aro EM, Gollan PJ. The small Ca 2+-binding protein CSE links Ca 2+ signalling with nitrogen metabolism and filament integrity in Anabaena sp. PCC 7120. BMC Microbiol 2020; 20:57. [PMID: 32160863 PMCID: PMC7065334 DOI: 10.1186/s12866-020-01735-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 02/24/2020] [Indexed: 02/02/2023] Open
Abstract
Background Filamentous cyanobacteria represent model organisms for investigating multicellularity. For many species, nitrogen-fixing heterocysts are formed from photosynthetic vegetative cells under nitrogen limitation. Intracellular Ca2+ has been implicated in the highly regulated process of heterocyst differentiation but its role remains unclear. Ca2+ is known to operate more broadly in metabolic signalling in cyanobacteria, although the signalling mechanisms are virtually unknown. A Ca2+-binding protein called the Ca2+ Sensor EF-hand (CSE) is found almost exclusively in filamentous cyanobacteria. Expression of asr1131 encoding the CSE protein in Anabaena sp. PCC 7120 was strongly induced by low CO2 conditions, and rapidly downregulated during nitrogen step-down. A previous study suggests a role for CSE and Ca2+ in regulation of photosynthetic activity in response to changes in carbon and nitrogen availability. Results In the current study, a mutant Anabaena sp. PCC 7120 strain lacking asr1131 (Δcse) was highly prone to filament fragmentation, leading to a striking phenotype of very short filaments and poor growth under nitrogen-depleted conditions. Transcriptomics analysis under nitrogen-replete conditions revealed that genes involved in heterocyst differentiation and function were downregulated in Δcse, while heterocyst inhibitors were upregulated, compared to the wild-type. Conclusions These results indicate that CSE is required for filament integrity and for proper differentiation and function of heterocysts upon changes in the cellular carbon/nitrogen balance. A role for CSE in transmitting Ca2+ signals during the first response to changes in metabolic homeostasis is discussed.
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Affiliation(s)
- Julia Walter
- Department of Biochemistry, Molecular Plant Biology, University of Turku, Tykistökatu 6A, 6. krs, 20520, Turku, Finland.,Present address: Department of Plant Sciences, Environmental Plant Physiology, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Francisco Leganés
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Calle Darwin 2, 28049, Madrid, Spain
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, Tykistökatu 6A, 6. krs, 20520, Turku, Finland
| | - Peter J Gollan
- Department of Biochemistry, Molecular Plant Biology, University of Turku, Tykistökatu 6A, 6. krs, 20520, Turku, Finland.
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Muro-Pastor AM, Hess WR. Regulatory RNA at the crossroads of carbon and nitrogen metabolism in photosynthetic cyanobacteria. Biochim Biophys Acta Gene Regul Mech 2019; 1863:194477. [PMID: 31884117 DOI: 10.1016/j.bbagrm.2019.194477] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/16/2019] [Accepted: 12/22/2019] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are photosynthetic bacteria that populate widely different habitats. Accordingly, cyanobacteria exhibit a wide spectrum of lifestyles, physiologies, and morphologies and possess genome sizes and gene numbers which may vary by up to a factor of ten within the phylum. Consequently, large differences exist between individual species in the size and complexity of their regulatory networks. Several non-coding RNAs have been identified that play crucial roles in the acclimation responses of cyanobacteria to changes in the environment. Some of these regulatory RNAs are conserved throughout the cyanobacterial phylum, while others exist only in a few taxa. Here we give an overview on characterized regulatory RNAs in cyanobacteria, with a focus on regulators of photosynthesis, carbon and nitrogen metabolism. However, chances are high that these regulators represent just the tip of the iceberg.
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Affiliation(s)
- Alicia M Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Sevilla, Spain
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104 Freiburg, Germany; University of Freiburg, Freiburg Institute for Advanced Studies, Albertstr. 19, D-79104 Freiburg, Germany.
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Torrado A, Valladares A, Puerto-Galán L, Hervás M, Navarro JA, Molina-Heredia FP. Cyt c6-3: A New Isoform of Photosynthetic Cyt c6 Exclusive to Heterocyst-Forming Cyanobacteria. Plant Cell Physiol 2017; 58:256-265. [PMID: 28007969 DOI: 10.1093/pcp/pcw184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
All known cyanobacteria contain Cyt c6, a small soluble electron carrier protein whose main function is to transfer electrons from the Cyt b6f complex to PSI, although it is also involved in respiration. We have previously described a second isoform of this protein, the Cyt c6-like, whose function remains unknown. Here we describe a third isoform of Cyt c6 (here called Cytc6-3), which is only found in heterocyst-forming filamentous cyanobacteria. Cyt c6-3 is expressed in vegetative cells but is specifically repressed in heterocysts cells under diazotrophic growth conditions. Although there is a close structural similarity between Cyt c6-3 and Cyt c6 related to the general protein folding, Cyt c6-3 presents differential electrostatic surface features as compared with Cyt c6, its expression is not copper dependent and has a low reactivity towards PSI. According to the different expression pattern, functional reactivity and structural properties, Cyt c6-3 has to play an as yet to be defined regulatory role related to heterocyst differentiation.
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Affiliation(s)
- Alejandro Torrado
- School of Medicine, Department of Anatomy and Neurobiology, Medical Science Campus of the University of Puerto Rico (MCS-UPR), San Juan, PR, USA
| | - Ana Valladares
- Department of Environmental, Earth and Geospatial Sciences, North Carolina Central University, Durham, North Carolina, USA
| | - Leonor Puerto-Galán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio, Sevilla, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas Seville, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Fernando P Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio, Sevilla, Spain
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Pratte BS, Thiel T. Fluorescence in situ Localization of Gene Expression Using a lacZ Reporter in the Heterocyst-forming Cyanobacterium Anabaena variabilis. Bio Protoc 2017; 7:e2084. [PMID: 34458415 DOI: 10.21769/bioprotoc.2084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/07/2016] [Accepted: 12/06/2016] [Indexed: 11/02/2022] Open
Abstract
One of the most successful fluorescent proteins, used as a reporter of gene expression in many bacterial, plant and animals, is green fluorescent protein and its modified forms, which also function well in cyanobacteria. However, these fluorescent proteins do not allow rapid and economical quantitation of the reporter gene product, as does the popular reporter gene lacZ, encoding the enzyme β-galactosidase. We provide here a protocol for the in situ localization of β-galactosidase activity in cyanobacterial cells. This allows the same strain to be used for both a simple, quantitative, colorimetric assay with the substrate ortho-nitrophenyl-β-galactoside (ONPG) and for sensitive, fluorescence-based, cell-type localization of gene expression using 5-dodecanolyaminofluorescein di-β-D-galactopyranoside (C12-FDG).
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Affiliation(s)
- Brenda S Pratte
- Department of Biology, University of Missouri - St. Louis, St. Louis, MO, USA
| | - Teresa Thiel
- Department of Biology, University of Missouri - St. Louis, St. Louis, MO, USA
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Magnuson A, Cardona T. Thylakoid membrane function in heterocysts. Biochim Biophys Acta 2015; 1857:309-19. [PMID: 26545609 DOI: 10.1016/j.bbabio.2015.10.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/30/2015] [Accepted: 10/29/2015] [Indexed: 01/19/2023]
Abstract
Multicellular cyanobacteria form different cell types in response to environmental stimuli. Under nitrogen limiting conditions a fraction of the vegetative cells in the filament differentiate into heterocysts. Heterocysts are specialized in atmospheric nitrogen fixation and differentiation involves drastic morphological changes on the cellular level, such as reorganization of the thylakoid membranes and differential expression of thylakoid membrane proteins. Heterocysts uphold a microoxic environment to avoid inactivation of nitrogenase by developing an extra polysaccharide layer that limits air diffusion into the heterocyst and by upregulating heterocyst-specific respiratory enzymes. In this review article, we summarize what is known about the thylakoid membrane in heterocysts and compare its function with that of the vegetative cells. We emphasize the role of photosynthetic electron transport in providing the required amounts of ATP and reductants to the nitrogenase enzyme. In the light of recent high-throughput proteomic and transcriptomic data, as well as recently discovered electron transfer pathways in cyanobacteria, our aim is to broaden current views of the bioenergetics of heterocysts. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux.
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Affiliation(s)
- Ann Magnuson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden.
| | - Tanai Cardona
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England, UK
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