1
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Xue J, Li S, Wang L, Zhao Y, Zhang L, Zheng Y, Zhang W, Chen Z, Jiang T, Sun Y. Enhanced fatty acid biosynthesis by Sigma28 in stringent responses contributes to multidrug resistance and biofilm formation in Helicobacter pylori. Antimicrob Agents Chemother 2024; 68:e0085024. [PMID: 39046242 PMCID: PMC11373199 DOI: 10.1128/aac.00850-24] [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: 06/20/2024] [Accepted: 07/08/2024] [Indexed: 07/25/2024] Open
Abstract
The metabolic state of bacteria significantly contributes to their resistance to antibiotics; however, the specific metabolic mechanisms conferring antimicrobial resistance in Helicobacter pylori remain largely understudied. Employing transcriptomic and non-targeted metabolomics, we characterized the metabolic reprogramming of H. pylori when challenged with antibiotic agents. We observed a notable increase in both genetic and key proteomic components involved in fatty acid biosynthesis. Inhibition of this pathway significantly enhanced the antibiotic susceptibility of the sensitive and multidrug-resistant H. pylori strains while also disrupting their biofilm-forming capacities. Further analysis revealed that antibiotic treatment induced a stringent response, triggering the expression of the hp0560-hp0557 operon regulated by Sigma28 (σ28). This activation in turn stimulated the fatty acid biosynthetic pathway, thereby enhancing the antibiotic tolerance of H. pylori. Our findings reveal a novel adaptive strategy employed by H. pylori to withstand antibiotic stress.
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Affiliation(s)
- Junyuan Xue
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
| | - Shutong Li
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Liyuan Wang
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
| | - Yican Zhao
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
| | - Lu Zhang
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
| | - Yantong Zheng
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
| | - Wenxin Zhang
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
| | - Zhenghong Chen
- Key Laboratory of Microbiology and Parasitology of Education Department of Guizhou, Guizhou Medical University, Guiyang, China
| | - Ting Jiang
- Jiangsu Luye Diagnostic Technology, Wuxi, China
| | - Yundong Sun
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Microbiology, School of Basic Medical Science, Shandong University, Jinan, Shandong, China
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Srivastava A, Thapa S, Chakdar H, Babele PK, Shukla P. Cyanobacterial myxoxanthophylls: biotechnological interventions and biological implications. Crit Rev Biotechnol 2024; 44:63-77. [PMID: 36137567 DOI: 10.1080/07388551.2022.2117682] [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: 04/09/2022] [Revised: 07/09/2022] [Accepted: 08/06/2022] [Indexed: 11/03/2022]
Abstract
Cyanobacteria safeguard their photosynthetic machinery from oxidative damage caused by adverse environmental factors such as high-intensity light. Together with many photoprotective compounds, they contain myxoxanthophylls, a rare group of glycosidic carotenoids containing a high number of conjugated double bonds. These carotenoids have been shown to: have strong photoprotective effects, contribute to the integrity of the thylakoid membrane, and upregulate in cyanobacteria under a variety of stress conditions. However, their metabolic potential has not been fully utilized in the stress biology of cyanobacteria and the pharmaceutical industry due to a lack of mechanistic understanding and their insufficient biosynthesis. This review summarizes current knowledge on: biological function, genetic regulation, biotechnological production, and pharmaceutical potential of myxoxanthophyll, with a focus on strain engineering and parameter optimization strategies for increasing their cellular content. The summarized knowledge can be utilized in cyanobacterial metabolic engineering to improve the stress tolerance of useful strains and enhance the commercial-scale synthesis of myxoxanthophyll for pharmaceutical uses.
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Affiliation(s)
- Amit Srivastava
- Department of Chemistry, Purdue University, West Lafayette, United States of America
| | - Shobit Thapa
- ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, India
| | - Hillol Chakdar
- ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, India
| | | | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
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3
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Olivan-Muro I, Sarasa-Buisan C, Guio J, Arenas J, Sevilla E, Fillat MF. Unbalancing Zur (FurB)-mediated homeostasis in Anabaena sp. PCC7120: Consequences on metal trafficking, heterocyst development and biofilm formation. Environ Microbiol 2023; 25:2142-2162. [PMID: 37315963 DOI: 10.1111/1462-2920.16434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/22/2023] [Indexed: 06/16/2023]
Abstract
Zinc is required for the activity of many enzymes and plays an essential role in gene regulation and redox homeostasis. In Anabaena (Nostoc) sp. PCC7120, the genes involved in zinc uptake and transport are controlled by the metalloregulator Zur (FurB). Comparative transcriptomics of a zur mutant (Δzur) with the parent strain unveiled unexpected links between zinc homeostasis and other metabolic pathways. A notable increase in the transcription of numerous desiccation tolerance-related genes, including genes involved in the synthesis of trehalose and the transference of saccharide moieties, among many others, was detected. Biofilm formation analysis under static conditions revealed a reduced capacity of Δzur filaments to form biofilms compared to the parent strain, and such capacity was enhanced when Zur was overexpressed. Furthermore, microscopy analysis revealed that zur expression is required for the correct formation of the envelope polysaccharide layer in the heterocyst, as Δzur cells showed reduced staining with alcian blue compared to Anabaena sp. PCC7120. We suggest that Zur is an important regulator of the enzymes involved in the synthesis and transport of the envelope polysaccharide layer, influencing heterocyst development and biofilm formation, both relevant processes for cell division and interaction with substrates in its ecological niche.
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Affiliation(s)
- Irene Olivan-Muro
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Cristina Sarasa-Buisan
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Jorge Guio
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Jesús Arenas
- Department of Animal Pathology, Unit of Microbiology and Immunology, Faculty of Veterinary, University of Zaragoza, Zaragoza, Spain
| | - Emma Sevilla
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Maria F Fillat
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
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4
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Kimura S, Sato M, Fan X, Ohmori M, Ehira S. The two-component response regulator OrrA confers dehydration tolerance by regulating avaKa expression in the cyanobacterium Anabaena sp. strain PCC 7120. Environ Microbiol 2022; 24:5165-5173. [PMID: 36054741 PMCID: PMC9804601 DOI: 10.1111/1462-2920.16162] [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: 06/28/2021] [Accepted: 08/06/2022] [Indexed: 01/05/2023]
Abstract
The cyanobacterium Anabaena sp. strain PCC 7120 exhibits dehydration tolerance. The regulation of gene expression in response to dehydration is crucial for the acquisition of dehydration tolerance, but the molecular mechanisms underlying dehydration responses remain unknown. In this study, the functions of the response regulator OrrA in the regulation of salt and dehydration responses were investigated. Disruption of orrA abolished or diminished the induction of hundreds of genes in response to salt stress and dehydration. Thus, OrrA is a principal regulator of both stress responses. In particular, OrrA plays a crucial role in dehydration tolerance because an orrA disruptant completely lost the ability to regrow after dehydration. Moreover, in the OrrA regulon, avaKa encoding a protein of unknown function was revealed to be indispensable for dehydration tolerance. OrrA and AvaK are conserved among the terrestrial cyanobacteria, suggesting their conserved functions in dehydration tolerance in cyanobacteria.
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Affiliation(s)
- Satoshi Kimura
- Department of Biochemistry and Molecular Biology, Faculty of ScienceSaitama UniversitySaitamaJapan
| | - Miho Sato
- Department of Biological Sciences, Graduate school of ScienceTokyo Metropolitan UniversityTokyoJapan
| | - Xingyan Fan
- Department of Biological Sciences, Graduate school of ScienceTokyo Metropolitan UniversityTokyoJapan
| | - Masayuki Ohmori
- Department of Biochemistry and Molecular Biology, Faculty of ScienceSaitama UniversitySaitamaJapan
| | - Shigeki Ehira
- Department of Biochemistry and Molecular Biology, Faculty of ScienceSaitama UniversitySaitamaJapan,Department of Biological Sciences, Graduate school of ScienceTokyo Metropolitan UniversityTokyoJapan
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5
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Chakdar H, Thapa S, Srivastava A, Shukla P. Genomic and proteomic insights into the heavy metal bioremediation by cyanobacteria. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127609. [PMID: 34772552 DOI: 10.1016/j.jhazmat.2021.127609] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/16/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
Heavy metals (HMs) pose a global ecological threat due to their toxic effects on aquatic and terrestrial life. Effective remediation of HMs from the environment can help to restore soil's fertility and ecological vigor, one of the key Sustainable Development Goals (SDG) set by the United Nations. The cyanobacteria have emerged as a potential option for bioremediation of HMs due to their unique adaptations and robust metabolic machineries. Generally, cyanobacteria deploy multifarious mechanisms such as biosorption, bioaccumulation, activation of metal transporters, biotransformation and induction of detoxifying enzymes to sequester and minimize the toxic effects of heavy metals. Therefore, understanding the physiological responses and regulation of adaptation mechanisms at molecular level is necessary to unravel the candidate genes and proteins which can be manipulated to improve the bioremediation efficiency of cyanobacteria. Chaperons, cellular metabolites (extracellular polymers, biosurfactants), transcriptional regulators, metal transporters, phytochelatins and metallothioneins are some of the potential targets for strain engineering. In the present review, we have discussed the potential of cyanobacteria for HM bioremediation and provided a deeper insight into their genomic and proteomic regulation of various tolerance mechanisms. These approaches might pave new possibilities of implementing genetic engineering strategies for improving bioremediation efficiency with a future perspective.
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Affiliation(s)
- Hillol Chakdar
- Microbial Technology Unit II, ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau 275103, Uttar Pradesh, India
| | - Shobit Thapa
- Microbial Technology Unit II, ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau 275103, Uttar Pradesh, India
| | - Amit Srivastava
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, ID 47907-2048, United States
| | - Pratyoosh Shukla
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India; Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
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6
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Xu HF, Raanan H, Dai GZ, Oren N, Berkowicz S, Murik O, Kaplan A, Qiu BS. Reading and surviving the harsh conditions in desert biological soil crust: The cyanobacterial viewpoint. FEMS Microbiol Rev 2021; 45:6308820. [PMID: 34165541 DOI: 10.1093/femsre/fuab036] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/22/2021] [Indexed: 12/18/2022] Open
Abstract
Biological soil crusts (BSCs) are found in drylands, cover ∼12% of the Earth's surface in arid and semi-arid lands and their destruction is considered an important promoter of desertification. These crusts are formed by the adhesion of soil particles to polysaccharides excreted mostly by filamentous cyanobacteria, which are the pioneers and main primary producers in BSCs. Desert BSCs survive in one of the harshest environments on Earth, and are exposed to daily fluctuations of extreme conditions. The cyanobacteria inhabiting these habitats must precisely read the changing conditions and predict, for example, the forthcoming desiccation. Moreover, they evolved a comprehensive regulation of multiple adaptation strategies to enhance their stress tolerance. Here we focus on what distinguishes cyanobacteria able to revive after dehydration from those that cannot. While important progress has been made in our understanding of physiological, biochemical and omics aspects, clarification of the sensing, signal transduction and responses enabling desiccation tolerance are just emerging. We plot the trajectory of current research and open questions ranging from general strategies and regulatory adaptations in the hydration/desiccation cycle, to recent advances in our understanding of photosynthetic adaptation. The acquired knowledge provides new insights to mitigate desertification and improve plant productivity under drought conditions.
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Affiliation(s)
- Hai-Feng Xu
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, Hubei, 430079 China
| | - Hagai Raanan
- Department of Plant Pathology and Weed Research, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 8531100 Israel
| | - Guo-Zheng Dai
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, Hubei, 430079 China
| | - Nadav Oren
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401 Israel
| | - Simon Berkowicz
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401 Israel.,Interuniversity Institute for Marine Sciences in Eilat, P.O.B 469, Eilat, 8810302 Israel
| | - Omer Murik
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401 Israel
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401 Israel
| | - Bao-Sheng Qiu
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, Hubei, 430079 China
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7
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Srivastava A, Varshney RK, Shukla P. Sigma Factor Modulation for Cyanobacterial Metabolic Engineering. Trends Microbiol 2020; 29:266-277. [PMID: 33229204 DOI: 10.1016/j.tim.2020.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 11/18/2022]
Abstract
Sigma (σ) factors are key regulatory proteins that control the transcription initiation in prokaryotes. In response to environmental or developmental cues, σ factors initiate the transcription of necessary genes responsible for maintaining a life-sustaining metabolic balance. Due to the significant role of σ factors in bacterial metabolism, their rational engineering for commercial metabolite production in photoautotrophic, cyanobacterial cells is a desirable venture. As cyanobacterial genomes typically encode multiple σ factors, effective execution of metabolic engineering efforts largely relies on uncovering the complicated gene regulatory network and further characterization of the members of σ factor regulatory circuits. This review outlines the prospects of σ factor in metabolic engineering of cyanobacteria, summarizes the challenges in the path towards an efficient strain construction and highlights the genomic context of putative regulators of cyanobacterial σ factors.
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Affiliation(s)
- Amit Srivastava
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Rajeev K Varshney
- Center of Excellence in Genomics and Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak-124001, Haryana, India.
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8
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Cyanobacterial sigma factors: Current and future applications for biotechnological advances. Biotechnol Adv 2020; 40:107517. [DOI: 10.1016/j.biotechadv.2020.107517] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 11/15/2022]
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9
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de Alvarenga LV, Lucius S, Vaz MGMV, Araújo WL, Hagemann M. The novel strain Desmonostoc salinum CCM-UFV059 shows higher salt and desiccation resistance compared to the model strain Nostoc sp. PCC7120. JOURNAL OF PHYCOLOGY 2020; 56:496-506. [PMID: 31925964 DOI: 10.1111/jpy.12968] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Desmonostoc salinum CCM-UFV059 (Desmonostoc) is a novel cyanobacterial strain of the order Nostocales isolated from a saline-alkaline lake. The acclimation towards salt and desiccation stress of Desmonostoc was compared to the related and well-characterized model strain Nostoc sp. PCC7120 (Nostoc). Salt-stressed cells of Desmonostoc maintained low cellular Na+ concentrations and accumulated high amounts of compatible solutes, mainly sucrose and to a lower extent trehalose. These features permitted Desmonostoc to grow and maintain photosynthesis at 2-fold higher salinities than Nostoc. Moreover, Desmonostoc also induced sucrose over-accumulation under desiccation, which allowed this strain to recover from this stress in contrast to Nostoc. Additional mechanisms such as the presence of highly unsaturated lipids in the membrane and an efficient ion transport system could also explain, at least partially, how Desmonostoc is able to acclimate to high salinities and to resist longer desiccation periods. Collectively, our results provide first insights into the physiological and metabolic adaptations explaining the remarkable high salt and desiccation tolerance, which qualify Desmonostoc as an attractive model for further analysis of stress acclimation among heterocystous N2 -fixing cyanobacteria.
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Affiliation(s)
- Luna Viggiano de Alvarenga
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
| | - Stefan Lucius
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
| | - Marcelo Gomes Marçal Vieira Vaz
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Wagner L Araújo
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Martin Hagemann
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
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10
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Wells KN, Videau P, Nelson D, Eiting JE, Philmus B. The influence of sigma factors and ribosomal recognition elements on heterologous expression of cyanobacterial gene clusters in Escherichia coli. FEMS Microbiol Lett 2019; 365:5047307. [PMID: 29982530 DOI: 10.1093/femsle/fny164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/28/2018] [Indexed: 12/16/2022] Open
Abstract
Cyanobacterial natural products offer new possibilities for drugs and lead compounds but many factors can inhibit the production of sufficient yields for pharmaceutical processes. While Escherichia coli and Streptomyces sp. have been used as heterologous expression hosts to produce cyanobacterial natural products, they have not met with resounding success largely due to their inability to recognize cyanobacterial promoter regions. Recent work has shown that the filamentous freshwater cyanobacterium Anabaena sp. strain PCC 7120 recognizes various cyanobacterial promoter regions and can produce lyngbyatoxin A from the native promoter. Introduction of Anabaena sigma factors into E. coli might allow the native transcriptional machinery to recognize cyanobacterial promoters. Here, all 12 Anabaena sigma factors were expressed in E. coli and subsets were found to initiate transcription from several cyanobacterial promoters based on transcriptional fusions to the chloramphenicol acetyltransferase (CAT) reporter. Expression of individual Anabaena sigma factors in E. coli did not result in lyngbyatoxin A production from its native cyanobacterial gene cluster, possibly hindered by deficiencies in recognition of cyanobacterial ribosomal binding sites by native E. coli translational machinery. This represents an important step toward engineering E. coli into a general heterologous expression host for cyanobacterial biosynthetic gene cluster expression.
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Affiliation(s)
- Kaitlyn N Wells
- Undergraduate Honors College, 450 Learning Innovation Center, Oregon State University, Corvallis, OR 97331, USA
| | - Patrick Videau
- Department of Pharmaceutical Sciences, College of Pharmacy, 203 Pharmacy Bldg., Oregon State University, Corvallis, OR 97331, USA
| | - Dylan Nelson
- Department of Pharmaceutical Sciences, College of Pharmacy, 203 Pharmacy Bldg., Oregon State University, Corvallis, OR 97331, USA
| | - Jessie E Eiting
- Department of Pharmaceutical Sciences, College of Pharmacy, 203 Pharmacy Bldg., Oregon State University, Corvallis, OR 97331, USA
| | - Benjamin Philmus
- Department of Pharmaceutical Sciences, College of Pharmacy, 203 Pharmacy Bldg., Oregon State University, Corvallis, OR 97331, USA
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11
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Babele PK, Kumar J, Chaturvedi V. Proteomic De-Regulation in Cyanobacteria in Response to Abiotic Stresses. Front Microbiol 2019; 10:1315. [PMID: 31263458 PMCID: PMC6584798 DOI: 10.3389/fmicb.2019.01315] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 05/27/2019] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are oxygenic photoautotrophs, exhibiting a cosmopolitan distribution in almost all possible environments and are significantly responsible for half of the global net primary productivity. They are well adapted to the diverse environments including harsh conditions by evolving a range of fascinating repertoires of unique biomolecules and secondary metabolites to support their growth and survival. These phototrophs are proved as excellent models for unraveling the mysteries of basic biochemical and physiological processes taking place in higher plants. Several known species of cyanobacteria have tremendous biotechnological applications in diverse fields such as biofuels, biopolymers, secondary metabolites and much more. Due to their potential biotechnological and commercial applications in various fields, there is an imperative need to engineer robust cyanobacteria in such a way that they can tolerate and acclimatize to ever-changing environmental conditions. Adaptations to stress are mainly governed by a precise gene regulation pathways resulting in the expression of novel protein/enzymes and metabolites. Despite the demand, till date few proteins/enzymes have been identified which play a potential role in improving tolerance against abiotic stresses. Therefore, it is utmost important to study environmental stress responses related to post-genomic investigations, including proteomic changes employing advanced proteomics, synthetic and structural biology workflows. In this respect, the study of stress proteomics offers exclusive advantages to scientists working on these aspects. Advancements on these fields could be helpful in dissecting, characterization and manipulation of physiological and metabolic systems of cyanobacteria to understand the stress induced proteomic responses. Till date, it remains ambiguous how cyanobacteria perceive changes in the ambient environment that lead to the stress-induced proteins thus metabolic deregulation. This review briefly describes the current major findings in the fields of proteome research on the cyanobacteria under various abiotic stresses. These findings may improve and advance the information on the role of different class of proteins associated with the mechanism(s) of stress mitigation in cyanobacteria under harsh environmental conditions.
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Affiliation(s)
- Piyoosh Kumar Babele
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Jay Kumar
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Venkatesh Chaturvedi
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
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Brenes‐Álvarez M, Mitschke J, Olmedo‐Verd E, Georg J, Hess WR, Vioque A, Muro‐Pastor AM. Elements of the heterocyst‐specific transcriptome unravelled by co‐expression analysis inNostocsp. PCC 7120. Environ Microbiol 2019; 21:2544-2558. [DOI: 10.1111/1462-2920.14647] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/06/2019] [Accepted: 05/01/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Manuel Brenes‐Álvarez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
| | - Jan Mitschke
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of Freiburg D‐79104 Freiburg Germany
| | - Elvira Olmedo‐Verd
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
| | - Jens Georg
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of Freiburg D‐79104 Freiburg Germany
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of Freiburg D‐79104 Freiburg Germany
- Freiburg Institute for Advanced Studies, University of Freiburg D‐79104 Freiburg Germany
| | - Agustín Vioque
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
| | - Alicia M. Muro‐Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
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13
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Urrejola C, Alcorta J, Salas L, Vásquez M, Polz MF, Vicuña R, Díez B. Genomic Features for Desiccation Tolerance and Sugar Biosynthesis in the Extremophile Gloeocapsopsis sp. UTEX B3054. Front Microbiol 2019; 10:950. [PMID: 31134010 PMCID: PMC6513891 DOI: 10.3389/fmicb.2019.00950] [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: 05/04/2018] [Accepted: 04/15/2019] [Indexed: 01/06/2023] Open
Abstract
For tolerating extreme desiccation, cyanobacteria are known to produce both compatible solutes at intracellular level and a copious amount of exopolysaccharides as a protective coat. However, these molecules make cyanobacterial cells refractory to a broad spectrum of cell disruption methods, hindering genome sequencing, and molecular studies. In fact, few genomes are already available from cyanobacteria from extremely desiccated environments such as deserts. In this work, we report the 5.4 Mbp draft genome (with 100% of completeness in 105 contigs) of Gloeocapsopsis sp. UTEX B3054 (subsection I; Order Chroococcales), a cultivable sugar-rich and hardly breakable hypolithic cyanobacterium from the Atacama Desert. Our in silico analyses focused on genomic features related to sugar-biosynthesis and adaptation to dryness. Among other findings, screening of Gloeocapsopsis genome revealed a unique genetic potential related to the biosynthesis and regulation of compatible solutes and polysaccharides. For instance, our findings showed for the first time a novel genomic arrangement exclusive of Chroococcaceae cyanobacteria associated with the recycling of trehalose, a compatible solute involved in desiccation tolerance. Additionally, we performed a comparative genome survey and analyses to entirely predict the highly diverse pool of glycosyltransferases enzymes, key players in polysaccharide biosynthesis and the formation of a protective coat to dryness. We expect that this work will set the fundamental genomic framework for further research on microbial tolerance to desiccation and to a wide range of other extreme environmental conditions. The study of microorganisms like Gloeocapsopsis sp. UTEX B3054 will contribute to expand our limited understanding regarding water optimization and molecular mechanisms allowing extremophiles to thrive in xeric environments such as the Atacama Desert.
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Affiliation(s)
- Catalina Urrejola
- Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jaime Alcorta
- Laboratorio de Ecología Microbiana de Sistemas Extremos, Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Loreto Salas
- 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
| | - Martin F Polz
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Rafael Vicuña
- 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
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14
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Gonzalez A, Riley KW, Harwood TV, Zuniga EG, Risser DD. A Tripartite, Hierarchical Sigma Factor Cascade Promotes Hormogonium Development in the Filamentous Cyanobacterium Nostoc punctiforme. mSphere 2019; 4:e00231-19. [PMID: 31043519 PMCID: PMC6495340 DOI: 10.1128/msphere.00231-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 04/12/2019] [Indexed: 11/24/2022] Open
Abstract
Cyanobacteria are prokaryotes capable of oxygenic photosynthesis, and frequently, nitrogen fixation as well. As a result, they contribute substantially to global primary production and nitrogen cycles. Furthermore, the multicellular filamentous cyanobacteria in taxonomic subsections IV and V are developmentally complex, exhibiting an array of differentiated cell types and filaments, including motile hormogonia, making them valuable model organisms for studying development. To investigate the role of sigma factors in the gene regulatory network (GRN) controlling hormogonium development, a combination of genetic, immunological, and time-resolved transcriptomic analyses were conducted in the model filamentous cyanobacterium Nostoc punctiforme, which, unlike other common model cyanobacteria, retains the developmental complexity of field isolates. The results support a model where the hormogonium GRN is driven by a hierarchal sigma factor cascade, with sigJ activating the expression of both sigC and sigF, as well as a substantial portion of additional hormogonium-specific genes, including those driving changes to cellular architecture. In turn, sigC regulates smaller subsets of genes for several processes, plays a dominant role in promoting reductive cell division, and may also both positively and negatively regulate sigJ to reinforce the developmental program and coordinate the timing of gene expression, respectively. In contrast, the sigF regulon is extremely limited. Among genes with characterized roles in hormogonium development, only pilA shows stringent sigF dependence. For sigJ-dependent genes, a putative consensus promoter was also identified, consisting primarily of a highly conserved extended -10 region, here designated a J-Box, which is widely distributed among diverse members of the cyanobacterial lineage.IMPORTANCE Cyanobacteria are integral to global carbon and nitrogen cycles, and their metabolic capacity coupled with their ease of genetic manipulation make them attractive platforms for applications such as biomaterial and biofertilizer production. Achieving these goals will likely require a detailed understanding and precise rewiring of these organisms' GRNs. The complex phenotypic plasticity of filamentous cyanobacteria has also made them valuable models of prokaryotic development. However, current research has been limited by focusing primarily on a handful of model strains which fail to reflect the phenotypes of field counterparts, potentially limiting biotechnological advances and a more comprehensive understanding of developmental complexity. Here, using Nostoc punctiforme, a model filamentous cyanobacterium that retains the developmental range of wild isolates, we define previously unknown definitive roles for a trio of sigma factors during hormogonium development. These findings substantially advance our understanding of cyanobacterial development and gene regulation and could be leveraged for future applications.
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Affiliation(s)
- Alfonso Gonzalez
- Department of Biology, University of the Pacific, Stockton, California, USA
| | - Kelsey W Riley
- Department of Biology, University of the Pacific, Stockton, California, USA
| | - Thomas V Harwood
- Department of Biology, University of the Pacific, Stockton, California, USA
| | - Esthefani G Zuniga
- Department of Biology, University of the Pacific, Stockton, California, USA
| | - Douglas D Risser
- Department of Biology, University of the Pacific, Stockton, California, USA
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15
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Flores C, Santos M, Pereira SB, Mota R, Rossi F, De Philippis R, Couto N, Karunakaran E, Wright PC, Oliveira P, Tamagnini P. The alternative sigma factor SigF is a key player in the control of secretion mechanisms inSynechocystissp. PCC 6803. Environ Microbiol 2018; 21:343-359. [DOI: 10.1111/1462-2920.14465] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/14/2018] [Accepted: 10/31/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Carlos Flores
- Bioengineering and Synthetic Microbiology Group; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- Bioengineering and Synthetic Microbiology Group; IBMC - Instituto de Biologia Celular e Molecular, Universidade do Porto; Porto Portugal
- Departamento de Biologia Molecular; ICBAS - Instituto de Ciências Biomédicas Abel Salazar; Porto Portugal
| | - Marina Santos
- Bioengineering and Synthetic Microbiology Group; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- Bioengineering and Synthetic Microbiology Group; IBMC - Instituto de Biologia Celular e Molecular, Universidade do Porto; Porto Portugal
- Departamento de Biologia Molecular; ICBAS - Instituto de Ciências Biomédicas Abel Salazar; Porto Portugal
| | - Sara B. Pereira
- Bioengineering and Synthetic Microbiology Group; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- Bioengineering and Synthetic Microbiology Group; IBMC - Instituto de Biologia Celular e Molecular, Universidade do Porto; Porto Portugal
| | - Rita Mota
- Bioengineering and Synthetic Microbiology Group; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- Bioengineering and Synthetic Microbiology Group; IBMC - Instituto de Biologia Celular e Molecular, Universidade do Porto; Porto Portugal
| | - Federico Rossi
- Department of Agrifood Production and Environmental Sciences; University of Florence; Florence Italy
| | - Roberto De Philippis
- Department of Agrifood Production and Environmental Sciences; University of Florence; Florence Italy
| | - Narciso Couto
- Department of Chemical and Biological Engineering; ChELSI Institute, University of Sheffield; Sheffield UK
| | - Esther Karunakaran
- Department of Chemical and Biological Engineering; ChELSI Institute, University of Sheffield; Sheffield UK
| | - Phillip C. Wright
- Department of Chemical and Biological Engineering; ChELSI Institute, University of Sheffield; Sheffield UK
| | - Paulo Oliveira
- Bioengineering and Synthetic Microbiology Group; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- Bioengineering and Synthetic Microbiology Group; IBMC - Instituto de Biologia Celular e Molecular, Universidade do Porto; Porto Portugal
| | - Paula Tamagnini
- Bioengineering and Synthetic Microbiology Group; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- Bioengineering and Synthetic Microbiology Group; IBMC - Instituto de Biologia Celular e Molecular, Universidade do Porto; Porto Portugal
- Faculdade de Ciências, Departamento de Biologia; Universidade do Porto; Porto Portugal
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16
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Singh H. Desiccation and radiation stress tolerance in cyanobacteria. J Basic Microbiol 2018; 58:813-826. [PMID: 30080267 DOI: 10.1002/jobm.201800216] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/29/2018] [Accepted: 07/16/2018] [Indexed: 11/10/2022]
Abstract
Cyanobacteria are among the oldest living organisms on this planet, existing since more than 3 billion years. They are ideal organisms for investigating biological processes such as photosynthesis, respiration, circadian rhythm, photoregulation of gene expression, developmental gene rearrangements, and specialized cell differentiation. They are nearly ubiquitous in distribution, have colonized a wide range of ecosystems including soil, air, dry rock, and aquatic systems, and even occupy extreme niches that are inaccessible to other organisms. Such wide ecological distribution reflects their capacity to acclimate to extreme environments. They show great adaptive abilities and have survived various adverse physiological growth conditions like desiccation, high temperatures, extreme pH, cold, osmosis, salt, light, nitrogen, and high salinity. Their ancient origin and surviving through numerous stresses during evolution indicates their remarkable capabilities to survive and prevail under different environmental and man-made stresses. It has been hypothesized that similar and overlap stress response mechanisms help them to survive different stresses. It has been stated that responses against stresses like radiation has been accidental-exhibited because of similar response against desiccation stress, which has prevailed more during evolution. These overlaps and similarities in stress responses have been instrumental in making these organisms a large class of biological entities today. Present review discuss about stress tolerance in cyanobacteria against two extreme stresses - desiccation and gamma radiation. It also discuss the commonality and underlying molecular mechanisms in these two stress responses.
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Affiliation(s)
- Harinder Singh
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS (Deemed-to-be) University, Vile Parle (W), Mumbai, India
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17
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Characterization, genetic regulation and production of cyanobacterial exopolysaccharides and its applicability for heavy metal removal. Carbohydr Polym 2018; 179:228-243. [DOI: 10.1016/j.carbpol.2017.09.091] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/15/2017] [Accepted: 09/26/2017] [Indexed: 11/18/2022]
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18
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Bell N, Lee JJ, Summers ML. Characterization and in vivo regulon determination of an ECF sigma factor and its cognate anti-sigma factor in Nostoc punctiforme. Mol Microbiol 2017; 104:179-194. [PMID: 28105698 DOI: 10.1111/mmi.13620] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2017] [Indexed: 12/21/2022]
Abstract
Based on primary sequence comparisons and genomic context, Npun_F4153 (SigG)/Npun_F4154 (SapG) of the cyanobacterium Nostoc punctiforme were hypothesized to encode an ECF sigma factor/anti-sigma factor pair. Transcription of sigG increased in heterocysts and akinetes, and after EDTA treatment. Interaction between SigG and the predicted cytoplasmic domain of SapG was observed in vitro. A SigG-GFP translational fusion protein localized to the periphery of vegetative cells in vivo, but lost this association following heat stress. A sigG mutant was unable to survive envelope damage caused by heat or EDTA, but was able to form functional heterocysts. Akinetes in the mutant strain appeared normal, but these cultures were less resistant to lysozyme and cold treatments than those of the wild-type strain. The SigG in vivo regulon was determined before and during akinete differentiation using DNA microarray analysis, and found to include multiple genes with putative association to the cell envelope. Mapped promoters common to both arrays enabled identification of a SigG promoter-binding motif that was supported in vivo by reporter studies, and in vitro by run-off transcription experiments. These findings support SigG/SapG as a sigma/anti-sigma pair involved in repair of envelope damage resulting from exogenous sources or cellular differentiation.
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Affiliation(s)
- Nicole Bell
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, CA, 91330-8303, USA
| | - Jamie J Lee
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, CA, 91330-8303, USA
| | - Michael L Summers
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, CA, 91330-8303, USA
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19
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Srivastava A, Brilisauer K, Rai AK, Ballal A, Forchhammer K, Tripathi AK. Down-Regulation of the Alternative Sigma Factor SigJ Confers a Photoprotective Phenotype to Anabaena PCC 7120. PLANT & CELL PHYSIOLOGY 2017; 58:287-297. [PMID: 27837096 DOI: 10.1093/pcp/pcw188] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
Alternative sigma factors belonging to Group 3 are thought to play an important role in the adaptation of cyanobacteria to environmental challenges by altering expression of genes needed for coping with such stresses. In this study, the role of an alternative sigma factor, SigJ, was analyzed in the filamentous nitrogen-fixing cyanobacterium, Anabaena sp. PCC 7120 by knocking down the expression of the sigJ gene (alr0277) employing an antisense RNA-mediated approach. In the absence of any stress, the knock-down (KD0277) or the wild-type strain both grew similarly. Upon exposure to high-intensity light, KD0277 showed substantially reduced bleaching of its pigments, higher photosynthetic activity and consequently better survival than the wild type. KD0277 also showed an enhanced accumulation of two carotenoids, which were identified as myxoxanthophyll and keto-myxoxanthophyll. Further, KD0277 was more tolerant to ammonium-triggered photodamage than the wild type. Moreover, PSII was better protected against photodamage in KD0277 than in the wild type. Down-regulation of sigJ in Anabaena PCC 7120, however, reduced its ability to cope with desiccation. This study demonstrates that down-regulation of the sigJ gene in Anabaena PCC 7120 differentially affects its ability to tolerate two environmentally relevant stresses, i.e. high-intensity light and desiccation.
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Affiliation(s)
- Amit Srivastava
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Klaus Brilisauer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle, Tübingen, Germany
| | - Ashutosh K Rai
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai, India
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle, Tübingen, Germany
| | - Anil K Tripathi
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
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20
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Ehira S, Miyazaki S. Regulation of Genes Involved in Heterocyst Differentiation in the Cyanobacterium Anabaena sp. Strain PCC 7120 by a Group 2 Sigma Factor SigC. Life (Basel) 2015; 5:587-603. [PMID: 25692906 PMCID: PMC4390870 DOI: 10.3390/life5010587] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/06/2015] [Accepted: 02/11/2015] [Indexed: 11/17/2022] Open
Abstract
The filamentous cyanobacterium Anabaena sp. strain PCC 7120 differentiates specialized cells for nitrogen fixation called heterocysts upon limitation of combined nitrogen in the medium. During heterocyst differentiation, expression of approximately 500 genes is upregulated with spatiotemporal regulation. In the present study, we investigated the functions of sigma factors of RNA polymerase in the regulation of heterocyst differentiation. The transcript levels of sigC, sigE, and sigG were increased during heterocyst differentiation, while expression of sigJ was downregulated. We carried out DNA microarray analysis to identify genes regulated by SigC, SigE, and SigG. It was indicated that SigC regulated the expression of genes involved in heterocyst differentiation and functions. Moreover, genes regulated by SigC partially overlapped with those regulated by SigE, and deficiency of SigC was likely to be compensated by SigE.
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Affiliation(s)
- Shigeki Ehira
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
| | - Shogo Miyazaki
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
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21
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Ambastha V, Tripathy BC, Tiwari BS. Programmed cell death in plants: A chloroplastic connection. PLANT SIGNALING & BEHAVIOR 2015; 10:e989752. [PMID: 25760871 PMCID: PMC4622501 DOI: 10.4161/15592324.2014.989752] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 05/18/2023]
Abstract
Programmed cell death (PCD) is an integral cellular program by which targeted cells culminate to demise under certain developmental and pathological conditions. It is essential for controlling cell number, removing unwanted diseased or damaged cells and maintaining the cellular homeostasis. The details of PCD process has been very well elucidated and characterized in animals but similar understanding of the process in plants has not been achieved rather the field is still in its infancy that sees some sporadic reports every now and then. The plants have 2 energy generating sub-cellular organelles- mitochondria and chloroplasts unlike animals that just have mitochondria. The presence of chloroplast as an additional energy transducing and ROS generating compartment in a plant cell inclines to advocate the involvement of chloroplasts in PCD execution process. As chloroplasts are supposed to be progenies of unicellular photosynthetic organisms that evolved as a result of endosymbiosis, the possibility of retaining some of the components involved in bacterial PCD by chloroplasts cannot be ruled out. Despite several excellent reviews on PCD in plants, there is a void on an update of information at a place on the regulation of PCD by chloroplast. This review has been written to provide an update on the information supporting the involvement of chloroplast in PCD process and the possible future course of the field.
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Affiliation(s)
- Vivek Ambastha
- School of Life Sciences; Jawaharlal Nehru University; New Delhi, India
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22
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Sucrose synthesis in the nitrogen-fixing Cyanobacterium Anabaena sp. strain PCC 7120 is controlled by the two-component response regulator OrrA. Appl Environ Microbiol 2014; 80:5672-9. [PMID: 25002430 DOI: 10.1128/aem.01501-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The filamentous, nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120 accumulates sucrose as a compatible solute against salt stress. Sucrose-phosphate synthase activity, which is responsible for the sucrose synthesis, is increased by salt stress, but the mechanism underlying the regulation of sucrose synthesis remains unknown. In the present study, a response regulator, OrrA, was shown to control sucrose synthesis. Expression of spsA, which encodes a sucrose-phosphate synthase, and susA and susB, which encode sucrose synthases, was induced by salt stress. In the orrA disruptant, salt induction of these genes was completely abolished. The cellular sucrose level of the orrA disruptant was reduced to 40% of that in the wild type under salt stress conditions. Moreover, overexpression of orrA resulted in enhanced expression of spsA, susA, and susB, followed by accumulation of sucrose, without the addition of NaCl. We also found that SigB2, a group 2 sigma factor of RNA polymerase, regulated the early response to salt stress under the control of OrrA. It is concluded that OrrA controls sucrose synthesis in collaboration with SigB2.
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23
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Yoshimura H, Ikeuchi M, Ohomori M. Cell surface-associated proteins in the filamentous cyanobacterium Anabaena sp. strain PCC 7120. Microbes Environ 2012; 27:538-43. [PMID: 23059722 PMCID: PMC4103569 DOI: 10.1264/jsme2.me12091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The cell surface senses environmental changes first and transfers signals into the cell. To understand the response to environmental changes, it is necessary to analyze cell surface components, particularly cell surface-associated proteins. We therefore investigated cell surface-associated proteins from the filamentous cyanobacterium Anabaena sp. strain PCC 7120. The cell surface-associated proteins extracted by an acidic buffer were resolved by SDS-PAGE. Eighteen proteins were identified from resolved bands by amino-terminal sequencing. Analysis of cell surface-associated proteins indicated that several proteins among them were involved in nucleic acid binding, protein synthesis, proteolytic activity and electron transfer, and other proteins were involved in the stress response.
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Affiliation(s)
- Hidehisa Yoshimura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3–8–1 Komaba, Meguro-ku, Tokyo 153–8902, Japan.
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24
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Desiccation-inducible genes are related to N(2)-fixing system under desiccation in a terrestrial cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1263-9. [PMID: 22503828 DOI: 10.1016/j.bbabio.2012.03.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/23/2012] [Accepted: 03/24/2012] [Indexed: 01/25/2023]
Abstract
Terrestrial cyanobacteria have various desiccation-tolerant systems, which are controlled by desiccation tolerance-related genes. Anabaena (Nostoc) sp. strain PCC 7120 is a derivative of the terrestrial cyanobacterium Nostoc and is a useful strain for molecular biological analysis. To identify desiccation tolerance-related genes, we selected and disrupted various genes (all0801, all0875, alr3090, alr3800, all4052, all4477, and alr5182) and examined their gene expression patterns and predicted their functions. Analyses of gene disruptants showed that viability of the disruptants only decreased under N(2)-fixing conditions during desiccation, and the decrease in viability was negatively correlated with the gene expression pattern during desiccation. These data suggest that terrestrial cyanobacteria may acclimate to desiccation stress via N(2) fixation by using desiccation inducible genes, which are not only related to nitrogen fixation or nitrogen metabolism but also to other systems such as metabolism, transcription, and protein repair for protection against desiccation damage under nitrogen-fixing conditions. Further, a photosynthetic gene is required for desiccation tolerance. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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25
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Pandey S, Rai R, Rai LC. Proteomics combines morphological, physiological and biochemical attributes to unravel the survival strategy of Anabaena sp. PCC7120 under arsenic stress. J Proteomics 2011; 75:921-37. [PMID: 22057044 DOI: 10.1016/j.jprot.2011.10.011] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Revised: 09/13/2011] [Accepted: 10/17/2011] [Indexed: 11/30/2022]
Abstract
Proteomics in conjunction with morphological, physiological and biochemical variables has been employed for the first time to unravel survival strategies of the diazotrophic cyanobacterium Anabaena sp. PCC7120 under Arsenic (As) stress. Significant reduction in growth, carbon fixation, nitrogenase activity and chlorophyll content after 1 day (1d) and recovery after 15 days (15d) of As exposure indicates the acclimation of the test organism against As stress. The formation of akinete like structures is a novel observation never reported before in Anabaena sp. PCC7120. Proteomic characterization using 2-DE showed average 537, 422 and 439 spots in control, 1 and 15d treatment respectively. MALDI-TOF and LC-MS of As-treated Anabaena revealed a total of 45 differentially expressed proteins, of which 13 were novel (hypothetical) ones. Down-regulation of phosphoglycerate kinase (PGK), fructose bisphosphate aldolase II (FBA II), fructose 1,6 bisphosphatase (FBPase), transketolase (TK), and ATP synthase on day 1 and their significant recovery on the 15th day presumably maintained the glycolysis, pentose phosphate pathway (PPP) and turnover rate of Calvin cycle, hence survival of the test organism. Up-regulation of catalase (CAT), peroxiredoxin (Prx), thioredoxin (Trx) and oxidoreductase appears to protect the cells from oxidative stress. Appreciable induction in phytochelatin content (2.4 fold), GST activity (2.3 fold), and transcripts of phytochelatin synthase (5.0 fold), arsenate reductase (8.5 fold) and arsenite efflux genes - asr1102 (5.0 fold), alr1097 (4.7 fold) reiterates their role in As sequestration and shielding of the organism from As toxicity. While up-regulated metabolic and antioxidative defense proteins, phytochelatin and GST work synchronously, the ars genes play a central role in detoxification and survival of Anabaena under As stress. The proposed hypothetical model explains the interaction of metabolic proteins associated with the survival of Anabaena sp. PCC7120 under As stress.
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Affiliation(s)
- Sarita Pandey
- Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-221005, India
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26
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Ehira S, Ohmori M. NrrA, a nitrogen-regulated response regulator protein, controls glycogen catabolism in the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120. J Biol Chem 2011; 286:38109-38114. [PMID: 21926170 DOI: 10.1074/jbc.m111.289124] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium in which certain vegetative cells differentiate into heterocysts that are specialized cells for nitrogen fixation. Heterocysts are unable to carry out photosynthesis and depend on vegetative cells for carbohydrate to generate ATP and reductants required for nitrogen fixation. Thus, carbohydrate metabolism is very important for nitrogen fixation in the filamentous cyanobacteria; however, its regulatory mechanism remains unknown. In the present study, a nitrogen-regulated response regulator NrrA, which is a transcriptional regulator involved in heterocyst differentiation, was shown to control glycogen catabolism. The transcript levels of genes involved in glycogen catabolism, such as glgP1 and xfp-gap1-pyk1-talB operon, were decreased by the nrrA disruption. Moreover, glycogen accumulation and depression of nitrogenase activities were observed in this disruptant. NrrA bound specifically to the promoter region of glgP1, encoding a glycogen phosphorylase, and to the promoter region of sigE, encoding a group 2 σ factor of RNA polymerase. SigE activated expression of the xfp operon, encoding enzymes of glycolysis and the pentose phosphate pathway. It is concluded that NrrA controls not only heterocyst differentiation but also glycogen catabolism in Anabaena sp. strain PCC 7120.
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Affiliation(s)
- Shigeki Ehira
- Department of Biological Science, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
| | - Masayuki Ohmori
- Department of Biological Science, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan.
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Mella-Herrera RA, Neunuebel MR, Kumar K, Saha SK, Golden JW. The sigE gene is required for normal expression of heterocyst-specific genes in Anabaena sp. strain PCC 7120. J Bacteriol 2011; 193:1823-32. [PMID: 21317330 PMCID: PMC3133031 DOI: 10.1128/jb.01472-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 01/31/2011] [Indexed: 11/20/2022] Open
Abstract
The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 produces specialized cells for nitrogen fixation called heterocysts. Previous work showed that the group 2 sigma factor sigE (alr4249; previously called sigF) is upregulated in differentiating heterocysts 16 h after nitrogen step-down. We now show that the sigE gene is required for normal heterocyst development and normal expression levels of several heterocyst-specific genes. Mobility shift assays showed that the transcription factor NtcA binds to sites in the upstream region of sigE and that this binding is enhanced by 2-oxoglutarate (2-OG). Deletions of the region containing the NtcA binding sites in P(sigE)-gfp reporter plasmids showed that the sites contribute to normal developmental regulation but are not essential for upregulation in heterocysts. Northern RNA blot analysis of nifH mRNA revealed delayed and reduced transcript levels during heterocyst differentiation in a sigE mutant background. Quantitative reverse transcription-PCR (qRT-PCR) analyses of the sigE mutant showed lower levels of transcripts for nifH, fdxH, and hglE2 but normal levels for hupL. We developed a P(nifHD)-gfp reporter construct that showed strong heterocyst-specific expression. Time-lapse microscopy of the P(nifHD)-gfp reporter in a sigE mutant background showed delayed development and undetectable green fluorescent protein (GFP) fluorescence. Overexpression of sigE caused accelerated heterocyst development, an increased heterocyst frequency, and premature expression of GFP fluorescence from the P(nifHD)-gfp reporter.
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Affiliation(s)
- Rodrigo A. Mella-Herrera
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
- Division of Biological Sciences, University of California—San Diego, La Jolla, California 92093-0116
| | - M. Ramona Neunuebel
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Krithika Kumar
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Sushanta K. Saha
- Division of Biological Sciences, University of California—San Diego, La Jolla, California 92093-0116
| | - James W. Golden
- Division of Biological Sciences, University of California—San Diego, La Jolla, California 92093-0116
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Azúa-Bustos A, González-Silva C, Mancilla RA, Salas L, Gómez-Silva B, McKay CP, Vicuña R. Hypolithic cyanobacteria supported mainly by fog in the coastal range of the Atacama Desert. MICROBIAL ECOLOGY 2011; 61:568-81. [PMID: 21188376 DOI: 10.1007/s00248-010-9784-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 11/25/2010] [Indexed: 05/25/2023]
Abstract
The Atacama Desert is one of the driest places on Earth, with an arid core highly adverse to the development of hypolithic cyanobacteria. Previous work has shown that when rain levels fall below ~1 mm per year, colonization of suitable quartz stones falls to virtually zero. Here, we report that along the coast in these arid regions, complex associations of cyanobacteria, archaea, and heterotrophic bacteria inhabit the undersides of translucent quartz stones. Colonization rates in these areas, which receive virtually no rain but mainly fog, are significantly higher than those reported inland in the hyperarid zone at the same latitude. Here, hypolithic colonization rates can be up to 80%, with all quartz rocks over 20 g being colonized. This finding strongly suggests that hypolithic microbial communities thriving in the seaward face of the Coastal Range can survive with fog as the main regular source of moisture. A model is advanced where the development of the hypolithic communities under quartz stones relies on a positive feedback between fog availability and the higher thermal conductivity of the quartz rocks, which results in lower daytime temperatures at the quartz-soil interface microenvironment.
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Affiliation(s)
- Armando Azúa-Bustos
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
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29
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Fujisawa T, Narikawa R, Okamoto S, Ehira S, Yoshimura H, Suzuki I, Masuda T, Mochimaru M, Takaichi S, Awai K, Sekine M, Horikawa H, Yashiro I, Omata S, Takarada H, Katano Y, Kosugi H, Tanikawa S, Ohmori K, Sato N, Ikeuchi M, Fujita N, Ohmori M. Genomic structure of an economically important cyanobacterium, Arthrospira (Spirulina) platensis NIES-39. DNA Res 2010; 17:85-103. [PMID: 20203057 PMCID: PMC2853384 DOI: 10.1093/dnares/dsq004] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A filamentous non-N2-fixing cyanobacterium, Arthrospira (Spirulina) platensis, is an important organism for industrial applications and as a food supply. Almost the complete genome of A. platensis NIES-39 was determined in this study. The genome structure of A. platensis is estimated to be a single, circular chromosome of 6.8 Mb, based on optical mapping. Annotation of this 6.7 Mb sequence yielded 6630 protein-coding genes as well as two sets of rRNA genes and 40 tRNA genes. Of the protein-coding genes, 78% are similar to those of other organisms; the remaining 22% are currently unknown. A total 612 kb of the genome comprise group II introns, insertion sequences and some repetitive elements. Group I introns are located in a protein-coding region. Abundant restriction-modification systems were determined. Unique features in the gene composition were noted, particularly in a large number of genes for adenylate cyclase and haemolysin-like Ca2+-binding proteins and in chemotaxis proteins. Filament-specific genes were highlighted by comparative genomic analysis.
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Affiliation(s)
- Takatomo Fujisawa
- Bioresource Information Center, Department of Biotechnology, National Institute of Technology and Evaluation, 2-10-49 Nishihara, Shibuya-ku, Tokyo 151-0066, Japan
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Abstract
Many multicellular cyanobacteria produce specialized nitrogen-fixing heterocysts. During diazotrophic growth of the model organism Anabaena (Nostoc) sp. strain PCC 7120, a regulated developmental pattern of single heterocysts separated by about 10 to 20 photosynthetic vegetative cells is maintained along filaments. Heterocyst structure and metabolic activity function together to accommodate the oxygen-sensitive process of nitrogen fixation. This article focuses on recent research on heterocyst development, including morphogenesis, transport of molecules between cells in a filament, differential gene expression, and pattern formation.
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Affiliation(s)
- Krithika Kumar
- Department of Biology, Texas A&M University, College Station, 77843, USA
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Stucken K, John U, Cembella A, Murillo AA, Soto-Liebe K, Fuentes-Valdés JJ, Friedel M, Plominsky AM, Vásquez M, Glöckner G. The smallest known genomes of multicellular and toxic cyanobacteria: comparison, minimal gene sets for linked traits and the evolutionary implications. PLoS One 2010; 5:e9235. [PMID: 20169071 PMCID: PMC2821919 DOI: 10.1371/journal.pone.0009235] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 01/14/2010] [Indexed: 11/24/2022] Open
Abstract
Cyanobacterial morphology is diverse, ranging from unicellular spheres or rods to multicellular structures such as colonies and filaments. Multicellular species represent an evolutionary strategy to differentiate and compartmentalize certain metabolic functions for reproduction and nitrogen (N2) fixation into specialized cell types (e.g. akinetes, heterocysts and diazocytes). Only a few filamentous, differentiated cyanobacterial species, with genome sizes over 5 Mb, have been sequenced. We sequenced the genomes of two strains of closely related filamentous cyanobacterial species to yield further insights into the molecular basis of the traits of N2 fixation, filament formation and cell differentiation. Cylindrospermopsis raciborskii CS-505 is a cylindrospermopsin-producing strain from Australia, whereas Raphidiopsis brookii D9 from Brazil synthesizes neurotoxins associated with paralytic shellfish poisoning (PSP). Despite their different morphology, toxin composition and disjunct geographical distribution, these strains form a monophyletic group. With genome sizes of approximately 3.9 (CS-505) and 3.2 (D9) Mb, these are the smallest genomes described for free-living filamentous cyanobacteria. We observed remarkable gene order conservation (synteny) between these genomes despite the difference in repetitive element content, which accounts for most of the genome size difference between them. We show here that the strains share a specific set of 2539 genes with >90% average nucleotide identity. The fact that the CS-505 and D9 genomes are small and streamlined compared to those of other filamentous cyanobacterial species and the lack of the ability for heterocyst formation in strain D9 allowed us to define a core set of genes responsible for each trait in filamentous species. We presume that in strain D9 the ability to form proper heterocysts was secondarily lost together with N2 fixation capacity. Further comparisons to all available cyanobacterial genomes covering almost the entire evolutionary branch revealed a common minimal gene set for each of these cyanobacterial traits.
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Affiliation(s)
- Karina Stucken
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
- Millenium Nucleus EMBA, Santiago, Chile
| | - Uwe John
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
| | - Allan Cembella
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
| | - Alejandro A. Murillo
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Katia Soto-Liebe
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Juan J. Fuentes-Valdés
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Maik Friedel
- Leibniz Institute for Age Research-Fritz Lipmann Institute, Jena, Germany
| | - Alvaro M. Plominsky
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Mónica Vásquez
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
- * E-mail: (MV); (GG)
| | - Gernot Glöckner
- Leibniz Institute for Age Research-Fritz Lipmann Institute, Jena, Germany
- Institute for Biochemistry I, University of Cologne, Cologne, Germany
- Leibniz Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany
- * E-mail: (MV); (GG)
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Pereira S, Zille A, Micheletti E, Moradas-Ferreira P, De Philippis R, Tamagnini P. Complexity of cyanobacterial exopolysaccharides: composition, structures, inducing factors and putative genes involved in their biosynthesis and assembly. FEMS Microbiol Rev 2009; 33:917-41. [DOI: 10.1111/j.1574-6976.2009.00183.x] [Citation(s) in RCA: 439] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Imamura S, Asayama M. Sigma factors for cyanobacterial transcription. GENE REGULATION AND SYSTEMS BIOLOGY 2009; 3:65-87. [PMID: 19838335 PMCID: PMC2758279 DOI: 10.4137/grsb.s2090] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cyanobacteria are photosynthesizing microorganisms that can be used as a model for analyzing gene expression. The expression of genes involves transcription and translation. Transcription is performed by the RNA polymerase (RNAP) holoenzyme, comprising a core enzyme and a sigma (sigma) factor which confers promoter selectivity. The unique structure, expression, and function of cyanobacterial sigma factors (and RNAP core subunits) are summarized here based on studies, reported previously. The types of promoter recognized by the sigma factors are also discussed with regard to transcriptional regulation.
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Affiliation(s)
- Sousuke Imamura
- Laboratory of Molecular Genetics, School of Agriculture, Ibaraki University, 3-21-1 Ami, Inashiki, Ibaraki 300-0393, Japan
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Transcription activation by NtcA and 2-oxoglutarate of three genes involved in heterocyst differentiation in the cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 2008; 190:6126-33. [PMID: 18658268 DOI: 10.1128/jb.00787-08] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Anabaena sp. strain PCC 7120, differentiation of heterocysts takes place in response to the external cue of combined nitrogen deprivation, allowing the organism to fix atmospheric nitrogen in oxic environments. NtcA, a global transcriptional regulator of cyanobacteria, is required for activation of the expression of multiple genes involved in heterocyst differentiation, including key regulators that are specific to the process. We have set up a fully defined in vitro system, which includes the purified Anabaena RNA polymerase, and have studied the effects of NtcA and its signaling effector 2-oxoglutarate on RNA polymerase binding, open complex formation, and transcript production from promoters of the hetC, nrrA, and devB genes that are activated by NtcA at different stages of heterocyst differentiation. Both RNA polymerase and NtcA could specifically bind to the target DNA in the absence of any effector. 2-Oxoglutarate had a moderate positive effect on NtcA binding, and NtcA had a limited positive effect on RNA polymerase recruitment at the promoters. However, a stringent requirement of both NtcA and 2-oxoglutarate was observed for the detection of open complexes and transcript production at the three investigated promoters. These results support a key role for 2-oxoglutarate in transcription activation in the developing heterocyst.
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Abstract
Group 1 and group 2 sigma factors are sigma factors of bacterial RNA polymerase responsible for transcription from consensus-type promoters. Thus, these sigma factors form the framework for basic transcriptional regulation in bacteria. Cyanobacteria are known to have various group 2 sigma factors, typically more than 4, but only recently the particular function of each sigma factor is being elucidated. In response to environmental signals such as nutrients, light and temperature, cyanobacteria change their transcriptional profile first by activating specific transcription factors and subsequently by modifying the basic transcriptional machinery, which is often involved in the regulation of group 2 sigma factors. In this article, we give an overview of the composition and evolution of group 2 sigma factors in cyanobacteria and summarize what was presently revealed regarding their function.
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Affiliation(s)
- Takashi Osanai
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 113-0032 Tokyo, Japan
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37
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Aldea MR, Mella-Herrera RA, Golden JW. Sigma factor genes sigC, sigE, and sigG are upregulated in heterocysts of the cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 2007; 189:8392-6. [PMID: 17873052 PMCID: PMC2168693 DOI: 10.1128/jb.00821-07] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used gfp transcriptional fusions to investigate the regulation of eight sigma factor genes during heterocyst development in the cyanobacterium Anabaena sp. strain PCC 7120. Reporter strains containing gfp fusions with the upstream regions of sigB2, sigD, sigI, and sigJ did not show developmental regulation. Time-lapse microscopy of sigC, sigE, and sigG reporter strains showed increased green fluorescent protein fluorescence in differentiating cells at 4 h, 16 h, and 9 h, respectively, after nitrogen step down.
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Affiliation(s)
- M Ramona Aldea
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, USA
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