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Turunen O, Saleem T, Kurkela J, Kallio P, Tyystjärvi T. Engineering RNA polymerase to construct biotechnological host strains of cyanobacteria. PHYSIOLOGIA PLANTARUM 2024; 176:e14263. [PMID: 38528669 DOI: 10.1111/ppl.14263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/27/2024]
Abstract
Application of cyanobacteria for bioproduction, bioremediation and biotransformation is being increasingly explored. Photoautotrophs are carbon-negative by default, offering a direct pathway to reducing emissions in production systems. More robust and versatile host strains are needed for constructing production strains that would function as efficient and carbon-neutral cyanofactories. We have tested if the engineering of sigma factors, regulatory units of the bacterial RNA polymerase, could be used to generate better host strains of the model cyanobacterium Synechocystis sp. PCC 6803. Overexpressing the stress-responsive sigB gene under the strong psbA2 promoter (SigB-oe) led to improved tolerance against heat, oxidative stress and toxic end-products. By targeting transcription initiation in the SigB-oe strain, we could simultaneously activate a wide spectrum of cellular protective mechanisms, including carotenoids, the HspA heat shock protein, and highly activated non-photochemical quenching. Yellow fluorescent protein was used to test the capacity of the SigB-oe strain to produce heterologous proteins. In standard conditions, the SigB-oe strain reached a similar production as the control strain, but when cultures were challenged with oxidative stress, the production capacity of SigB-oe surpassed the control strain. We also tested the production of growth-rate-controlled host strains via manipulation of RNA polymerase, but post-transcriptional regulation prevented excessive overexpression of the primary sigma factor SigA, and overproduction of the growth-restricting SigC factor was lethal. Thus, more research is needed before cyanobacteria growth can be manipulated by engineering RNA polymerase.
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Affiliation(s)
- Otso Turunen
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Tayyab Saleem
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Juha Kurkela
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Pauli Kallio
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Taina Tyystjärvi
- Department of Life Technologies/Molecular Plant Biology, University of Turku, Turku, Finland
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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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Mattila H, Mishra S, Tyystjärvi T, Tyystjärvi E. Singlet oxygen production by photosystem II is caused by misses of the oxygen evolving complex. THE NEW PHYTOLOGIST 2023; 237:113-125. [PMID: 36161283 PMCID: PMC10092662 DOI: 10.1111/nph.18514] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/10/2022] [Indexed: 06/12/2023]
Abstract
Singlet oxygen (1 O2 ) is a harmful species that functions also as a signaling molecule. In chloroplasts, 1 O2 is produced via charge recombination reactions in photosystem II, but which recombination pathway(s) produce triplet Chl and 1 O2 remains open. Furthermore, the role of 1 O2 in photoinhibition is not clear. We compared temperature dependences of 1 O2 production, photoinhibition, and recombination pathways. 1 O2 production by pumpkin thylakoids increased from -2 to +35°C, ruling out recombination of the primary charge pair as a main contributor. S2 QA - or S2 QB - recombination pathways, in turn, had too steep temperature dependences. Instead, the temperature dependence of 1 O2 production matched that of misses (failures of the oxygen (O2 ) evolving complex to advance an S-state). Photoinhibition in vitro and in vivo (also in Synechocystis), and in the presence or absence of O2 , had the same temperature dependence, but ultraviolet (UV)-radiation-caused photoinhibition showed a weaker temperature response. We suggest that the miss-associated recombination of P680 + QA - is the main producer of 1 O2 . Our results indicate three parallel photoinhibition mechanisms. The manganese mechanism dominates in UV radiation but also functions in white light. Mechanisms that depend on light absorption by Chls, having 1 O2 or long-lived P680 + as damaging agents, dominate in red light.
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Affiliation(s)
- Heta Mattila
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
| | - Sujata Mishra
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
| | - Taina Tyystjärvi
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
| | - Esa Tyystjärvi
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuFI‐20014TurkuFinland
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Mattila H, Tyystjärvi E. Light-induced damage to photosystem II at a very low temperature (195 K) depends on singlet oxygen. PHYSIOLOGIA PLANTARUM 2022; 174:e13824. [PMID: 36377045 PMCID: PMC10099935 DOI: 10.1111/ppl.13824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/26/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Photosynthetic organisms, like evergreen plants, may encounter strong light at low temperatures. Light, despite being the energy source of photosynthesis, irreversibly damages photosystem II (PSII). We illuminated plant thylakoid membranes and intact cyanobacterial cells at -78.5°C and assayed PSII activity with oxygen evolution or chlorophyll fluorescence, after thawing the sample. Both UV radiation and visible light damaged PSII of pumpkin (Cucurbita maxima) thylakoids at -78.5°C, but visible-light-induced photoinhibition at -78.5°C, unlike at +20°C, proceeded only in the presence of oxygen. A strong magnetic field that would decrease triplet chlorophyll formation by recombination of the primary radical pair slowed down photoinhibition at -78.5°C, suggesting that singlet oxygen produced via recombination of the primary pair is a major contributor to photoinhibition at -78.5°C. However, a magnetic field did not affect singlet oxygen production at +25°C. Thylakoids of winter leaves of an evergreen plant, Bergenia, were less susceptible to photoinhibition both at -78.5°C and +20°C, contained high amounts of carotenoids and produced little singlet oxygen (measured at +20°C), compared to thylakoids of summer leaves. In contrast, high carotenoid amount and low singlet oxygen yield did not protect a Synechocystis mutant from photoinhibition at -78.5°C. Thylakoids isolated from Arabidopsis thaliana grown under high light, which reduces PSII antenna size, were more resistant than control plants against photoinhibition at -78.5°C but not at +20°C, although carotenoid amounts were similar. The results indicate that visible-light-induced photoinhibition at -78.5°C depends on singlet oxygen, whereas photoinhibition at +20°C is largely independent of oxygen.
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Affiliation(s)
- Heta Mattila
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuTurkuFinland
| | - Esa Tyystjärvi
- Department of Life Technologies/Molecular Plant BiologyUniversity of TurkuTurkuFinland
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Rai R, Singh S, Rai KK, Raj A, Sriwastaw S, Rai LC. Regulation of antioxidant defense and glyoxalase systems in cyanobacteria. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 168:353-372. [PMID: 34700048 DOI: 10.1016/j.plaphy.2021.09.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/09/2021] [Accepted: 09/28/2021] [Indexed: 05/19/2023]
Abstract
Oxidative stress is common consequence of abiotic stress in plants as well as cyanobacteria caused by generation of reactive oxygen species (ROS), an inevitable product of respiration and photosynthetic electron transport. ROS act as signalling molecule at low concentration however, when its production exceeds the endurance capacity of antioxidative defence system, the organisms suffer oxidative stress. A highly toxic metabolite, methylglyoxal (MG) is also produced in cyanobacteria in response to various abiotic stresses which consequently augment the ensuing oxidative damage. Taking recourse to the common lineage of eukaryotic plants and cyanobacteria, it would be worthwhile to explore the regulatory role of glyoxalase system and antioxidative defense mechanism in combating abiotic stress in cyanobacteria. This review provides comprehensive information on the complete glyoxalase system (GlyI, GlyII and GlyIII) in cyanobacteria. Furthermore, it elucidates the recent understanding regarding the production of ROS and MG, noteworthy link between intracellular MG and ROS and its detoxification via synchronization of antioxidants (enzymatic and non-enzymatic) and glyoxalase systems using glutathione (GSH) as common co-factor.
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Affiliation(s)
- Ruchi Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shilpi Singh
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Krishna Kumar Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Alka Raj
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Sonam Sriwastaw
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - L C Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Rapid Transcriptional Reprogramming Triggered by Alteration of the Carbon/Nitrogen Balance Has an Impact on Energy Metabolism in Nostoc sp. PCC 7120. Life (Basel) 2020; 10:life10110297. [PMID: 33233741 PMCID: PMC7699953 DOI: 10.3390/life10110297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/12/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022] Open
Abstract
Nostoc (Anabaena) sp. PCC 7120 is a filamentous cyanobacterial species that fixes N2 to nitrogenous compounds using specialised heterocyst cells. Changes in the intracellular ratio of carbon to nitrogen (C/N balance) is known to trigger major transcriptional reprogramming of the cell, including initiating the differentiation of vegetative cells to heterocysts. Substantial transcriptional analysis has been performed on Nostoc sp. PCC 7120 during N stepdown (low to high C/N), but not during C stepdown (high to low C/N). In the current study, we shifted the metabolic balance of Nostoc sp. PCC 7120 cultures grown at 3% CO2 by introducing them to atmospheric conditions containing 0.04% CO2 for 1 h, after which the changes in gene expression were measured using RNAseq transcriptomics. This analysis revealed strong upregulation of carbon uptake, while nitrogen uptake and metabolism and early stages of heterocyst development were downregulated in response to the shift to low CO2. Furthermore, gene expression changes revealed a decrease in photosynthetic electron transport and increased photoprotection and reactive oxygen metabolism, as well a decrease in iron uptake and metabolism. Differential gene expression was largely attributed to change in the abundances of the metabolites 2-phosphoglycolate and 2-oxoglutarate, which signal a rapid shift from fluent photoassimilation to glycolytic metabolism of carbon after transition to low CO2. This work shows that the C/N balance in Nostoc sp. PCC 7120 rapidly adjusts the metabolic strategy through transcriptional reprogramming, enabling survival in the fluctuating environment.
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Izuhara T, Kaihatsu I, Jimbo H, Takaichi S, Nishiyama Y. Elevated Levels of Specific Carotenoids During Acclimation to Strong Light Protect the Repair of Photosystem II in Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2020; 11:1030. [PMID: 32733521 PMCID: PMC7358549 DOI: 10.3389/fpls.2020.01030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
The tolerance of photosynthesis to strong light increases in photosynthetic organisms during acclimation to strong light. We investigated the role of carotenoids in the protection of photosystem II (PSII) from photoinhibition after acclimation to strong light in the cyanobacterium Synechocystis sp. PCC 6803. In cells that had been grown under strong light at 1,000 μmol photons m-2 s-1 (SL), specific carotenoids, namely, zeaxanthin, echinenone, and myxoxanthophyll, accumulated at high levels, and the photoinhibition of PSII was less marked than in cells that had been grown under standard growth light at 70 μmol photons m-2 s-1 (GL). The rate of photodamage to PSII, as monitored in the presence of lincomycin, did not differ between cells grown under SL and GL, suggesting that the mitigation of photoinhibition after acclimation to SL might be attributable to the enhanced ability to repair PSII. When cells grown under GL were transferred to SL, the mitigation of photoinhibition of PSII occurred in two distinct stages: a first stage that lasted 4 h and the second stage that occurred after 8 h. During the second stage, the accumulation of specific carotenoids was detected, together with enhanced synthesis de novo of proteins that are required for the repair of PSII, such as the D1 protein, and suppression of the production of singlet oxygen (1O2). In the ΔcrtRΔcrtO mutant of Synechocystis, which lacks zeaxanthin, echinenone, and myxoxanthophyll, the mitigation of photoinhibition of PSII, the enhancement of protein synthesis, and the suppression of production of 1O2 were significantly impaired during the second stage of acclimation. Thus, elevated levels of the specific carotenoids during acclimation to strong light appeared to protect protein synthesis from 1O2, with the resultant mitigation of photoinhibition of PSII.
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Affiliation(s)
- Taichi Izuhara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ikumi Kaihatsu
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Haruhiko Jimbo
- Graduate School of Art and Sciences, The University of Tokyo, Tokyo, Japan
| | - Shinichi Takaichi
- Department of Molecular Microbiology, Faculty of Life Sciences, Tokyo University of Agriculture, Tokyo, Japan
| | - Yoshitaka Nishiyama
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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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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Valev D, Kurkela J, Tyystjärvi E, Tyystjärvi T. Testing the Potential of Regulatory Sigma Factor Mutants for Wastewater Purification or Bioreactor Run in High Light. Curr Microbiol 2020; 77:1590-1599. [PMID: 32266454 PMCID: PMC7334282 DOI: 10.1007/s00284-020-01973-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 03/27/2020] [Indexed: 11/25/2022]
Abstract
It is shown that a freshly inoculated culture of the model cyanobacterium Synechocystis sp. PCC 6803 consumed almost all phosphate and 50% of nitrate within 6 days from the nutrient-rich BG-11 growth medium, indicating potential of cyanobacteria to purify wastewaters. Synechocystis sp. PCC 6803 control strain also collected nutrients efficiently from a landfill leachate wastewater KA2 (5.9-6.9 mM ammonium and 0.073-0.077 mM phosphate). Wastewaters might induce oxidative stress to microalgae, which prompted us to test growth of sigma factor inactivation strains, as ΔsigBCE and ΔsigCDE strains show superior growth in chemically induced oxidative stress. All cyanobacterial strains, including a stress-sensitive strain ΔsigBCDE, grew well in KA2 for four days, indicating that KA2 did not cause immediate oxidative stress. Completely arrested growth and bleaching of ΔsigBCDE cells after one week in KA2 wastewater point to the importance of group 2 sigma factor-mediated changes in gene expression during wastewater treatment. The growth of ΔsigBCD was arrested early in un-buffered and Hepes buffered (pH 7.5) KA2. In ΔsigBCD, all phosphate transporter genes are upregulated in standard conditions, and ΔsigBCD cells showed growth defects in low-phosphate BG-11 medium. ΔsigBCD cells removed phosphate slower from KA2 than the control strain, but phosphate supplementation of KA2 did not improve growth of ΔsigBCD. The ΔsigBCE strain showed superior growth in a laboratory-scale bioreactor in bright light and removed phosphate even slightly more efficiently than the control strain if KA2 was Hepes buffered although ΔsigBCE grew slowly in un-buffered KA2 and in low-phosphate BG-11 medium. The results indicate that engineering expression of regulatory group 2 sigma factor(s) might be useful for practical applications.
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Affiliation(s)
- Dimitar Valev
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Juha Kurkela
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Esa Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Taina Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland.
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Hakkila K, Valev D, Antal T, Tyystjï Rvi E, Tyystjï Rvi T. Group 2 Sigma Factors are Central Regulators of Oxidative Stress Acclimation in Cyanobacteria. PLANT & CELL PHYSIOLOGY 2019; 60:436-447. [PMID: 30407607 DOI: 10.1093/pcp/pcy221] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/04/2018] [Indexed: 06/08/2023]
Abstract
Regulatory σ factors of the RNA polymerase (RNAP) adjust gene expression according to environmental cues when the cyanobacterium Synechocystis sp. PCC 6803 acclimates to suboptimal conditions. Here we show central roles of the non-essential group 2 σ factors in oxidative stress responses. Cells missing all group 2 σ factors fail to acclimate to chemically induced singlet oxygen, superoxide or H2O2 stresses, and lose pigments in high light. SigB and SigD are the major σ factors in oxidative stress, whereas SigC and SigE play only minor roles. The SigD factor is up-regulated in high light, singlet oxygen and H2O2 stresses, and overproduction of the SigD factor in the ΔsigBCE strain leads to superior growth of ΔsigBCE cells in those stress conditions. Superoxide does not induce the production of the SigD factor but instead SigB and SigC factors are moderately induced. The SigB factor alone in ΔsigCDE can support almost as fast growth in superoxide stress as the full complement of σ factors in the control strain, but an overdose of the stationary phase-related SigC factor causes growth arrest of ΔsigBDE in superoxide stress. A drastic decrease of the functional RNAP limits the transcription capacity of the cells in H2O2 stress, which explains why cyanobacteria are sensitive to H2O2. Formation of RNAP-SigB and RNAP-SigD holoenzymes is highly enhanced in H2O2 stress, and cells containing only SigB (ΔsigCDE) or SigD (ΔsigBCE) show superior growth in H2O2 stress.
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Affiliation(s)
- Kaisa Hakkila
- Department of Biochemistry/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Dimitar Valev
- Department of Biochemistry/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Taras Antal
- Biological Faculty, Moscow State University, Vorobyevi Gory, Moscow, Russia
| | - Esa Tyystjï Rvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Taina Tyystjï Rvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, Turku, Finland
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Comparative Targeted Proteomics of the Central Metabolism and Photosystems in SigE Mutant Strains of Synechocystis sp. PCC 6803. Molecules 2018; 23:molecules23051051. [PMID: 29723969 PMCID: PMC6102573 DOI: 10.3390/molecules23051051] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/17/2022] Open
Abstract
A targeted proteome analysis was conducted to investigate the SigE dependent-regulation of central metabolism in Synechocystis sp. PCC 6803 by directly comparing the protein abundance profiles among the wild type, a sigE deletion mutant (ΔsigE), and a sigE over-expression (sigEox) strains. Expression levels of 112 target proteins, including the central metabolism related-enzymes and the subunits of the photosystems, were determined by quantifying the tryptic peptides in the multiple reaction monitoring (MRM) mode of liquid-chromatography–triple quadrupole mass spectrometry (LC–MS/MS). Comparison with gene-expression data showed that although the abundance of Gnd protein was closely correlated with that of gnd mRNA, there were poor correlations for GdhA/gdhA and glycogen degradation-related genes such as GlgX/glgX and GlgP/glgP pairs. These results suggested that the regulation of protein translation and degradation played a role in regulating protein abundance. The protein abundance profile suggested that SigE overexpression reduced the proteins involved in photosynthesis and increased GdhA abundance, which is involved in the nitrogen assimilation pathway using NADPH. The results obtained in this study successfully demonstrated that targeted proteome analysis enables direct comparison of the abundance of central metabolism- and photosystem-related proteins.
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Stensjö K, Vavitsas K, Tyystjärvi T. Harnessing transcription for bioproduction in cyanobacteria. PHYSIOLOGIA PLANTARUM 2018; 162:148-155. [PMID: 28762505 DOI: 10.1111/ppl.12606] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/04/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
Sustainable production of biofuels and other valuable compounds is one of our future challenges. One tempting possibility is to use photosynthetic cyanobacteria as production factories. Currently, tools for genetic engineering of cyanobacteria are not good enough to exploit the full potential of cyanobacteria. A wide variety of expression systems will be required to adjust both the expression of heterologous enzyme(s) and metabolic routes to the best possible balance, allowing the optimal production of a particular substance. In bacteria, transcription, especially the initiation of transcription, has a central role in adjusting gene expression and thus also metabolic fluxes of cells according to environmental cues. Here we summarize the recent progress in developing tools for efficient cyanofactories, focusing especially on transcriptional regulation.
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Affiliation(s)
- Karin Stensjö
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Taina Tyystjärvi
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
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Havurinne V, Tyystjärvi E. Action Spectrum of Photoinhibition in the Diatom Phaeodactylum tricornutum. PLANT & CELL PHYSIOLOGY 2017; 58:2217-2225. [PMID: 29059446 DOI: 10.1093/pcp/pcx156] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 10/15/2017] [Indexed: 05/28/2023]
Abstract
Light-dependent electron transfer is necessary for photosynthesis, but light also damages PSII. Light-induced damage to PSII is called photoinhibition, and the damaging reactions of photoinhibition are still under debate. Diatoms possess an exotic combination of light-harvesting pigments, Chls a/c and fucoxanthin, making them an interesting platform for studying the photoreceptors of photoinhibition. We first confirmed the direct proportionality of photoinhibition to the photon flux density of incident light in the diatom Phaeodactylum tricornutum. Phaeodactylum is known for its efficient non-photochemical quenching, and the effect of this photoprotective mechanism on photoinhibition was tested. Photoinhibition proceeded essentially at the same rate in blue-light-grown Phaeodactylum cells that are capable of non-photochemical quenching and in red-light-grown, non-photochemical quenching-deficient cells. To obtain more insight into how the pigment composition of diatoms affects photoinhibition, we measured the action spectrum of photoinhibition in Phaeodactylum. In visible light, the action spectrum resembled the absorption spectrum of Phaeodactylum, and UV radiation caused much more photoinhibition than visible light. Comparison of the action spectrum of photoinhibition with the absorption spectrum and the excitation spectrum of 77 K PSII fluorescence emission confirmed that photosynthetic pigments are involved in photoinhibition, but the photoinhibitory efficiency of red light is weak, suggesting that the role of light-harvesting pigments as light receptors of photoinhibition is secondary. Finally, we compared photoinhibition in Phaeodactylum with that in other photosynthetic organisms, and our data indicate that the PSII reaction centers of Phaeodactylum are not particularly well protected against the primary damage of photoinhibition.
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Affiliation(s)
- Vesa Havurinne
- University of Turku, Department of Biochemistry/Molecular Plant Biology, 20014 Turku, Finland
| | - Esa Tyystjärvi
- University of Turku, Department of Biochemistry/Molecular Plant Biology, 20014 Turku, Finland
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Bersanini L, Allahverdiyeva Y, Battchikova N, Heinz S, Lespinasse M, Ruohisto E, Mustila H, Nickelsen J, Vass I, Aro EM. Dissecting the Photoprotective Mechanism Encoded by the flv4-2 Operon: a Distinct Contribution of Sll0218 in Photosystem II Stabilization. PLANT, CELL & ENVIRONMENT 2017; 40:378-389. [PMID: 27928824 DOI: 10.1111/pce.12872] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/17/2016] [Accepted: 11/20/2016] [Indexed: 06/06/2023]
Abstract
In Synechocystis sp. PCC 6803, the flv4-2 operon encodes the flavodiiron proteins Flv2 and Flv4 together with a small protein, Sll0218, providing photoprotection for Photosystem II (PSII). Here, the distinct roles of Flv2/Flv4 and Sll0218 were addressed, using a number of flv4-2 operon mutants. In the ∆sll0218 mutant, the presence of Flv2/Flv4 rescued PSII functionality as compared with ∆sll0218-flv2, where neither Sll0218 nor the Flv2/Flv4 heterodimer are expressed. Nevertheless, both the ∆sll0218 and ∆sll0218-flv2 mutants demonstrated deficiency in accumulation of PSII proteins suggesting a role for Sll0218 in PSII stabilization, which was further supported by photoinhibition experiments. Moreover, the accumulation of PSII assembly intermediates occurred in Sll0218-lacking mutants. The YFP-tagged Sll0218 protein localized in a few spots per cell at the external side of the thylakoid membrane, and biochemical membrane fractionation revealed clear enrichment of Sll0218 in the PratA-defined membranes, where the early biogenesis steps of PSII occur. Further, the characteristic antenna uncoupling feature of the ∆flv4-2 operon mutants is shown to be related to PSII destabilization in the absence of Sll0218. It is concluded that the Flv2/Flv4 heterodimer supports PSII functionality, while the Sll0218 protein assists PSII assembly and stabilization, including optimization of light harvesting.
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Affiliation(s)
- Luca Bersanini
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Yagut Allahverdiyeva
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Natalia Battchikova
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Steffen Heinz
- Molecular Plant Sciences, Ludwig-Maximillians-Universität München, Biozentrum, Grosshaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Maija Lespinasse
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Essi Ruohisto
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Henna Mustila
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Jörg Nickelsen
- Molecular Plant Sciences, Ludwig-Maximillians-Universität München, Biozentrum, Grosshaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, P.O. Box 521, H-6701, Szeged, Hungary
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
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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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16
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17
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Antal T, Kurkela J, Parikainen M, Kårlund A, Hakkila K, Tyystjärvi E, Tyystjärvi T. Roles of Group 2 Sigma Factors in Acclimation of the Cyanobacterium Synechocystis sp. PCC 6803 to Nitrogen Deficiency. PLANT & CELL PHYSIOLOGY 2016; 57:1309-1318. [PMID: 27095737 DOI: 10.1093/pcp/pcw079] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/10/2016] [Indexed: 06/05/2023]
Abstract
Acclimation of cyanobacteria to environmental conditions is mainly controlled at the transcriptional level, and σ factors of the RNA polymerase have a central role in this process. The model cyanobacterium Synechocystis sp. PCC 6803 has four non-essential group 2 σ factors (SigB, SigC, SigD and SigE) that regulate global metabolic responses to various adverse environmental conditions. Here we show that although none of the group 2 σ factors is essential for the major metabolic realignments induced by a short period of nitrogen starvation, the quadruple mutant without any group 2 σ factors and triple mutants missing both SigB and SigD grow slowly in BG-11 medium containing only 5% of the nitrate present in standard BG-11. These ΔsigBCDE, ΔsigBCD and ΔsigBDE strains lost PSII activity rapidly in low nitrogen and accumulated less glycogen than the control strain. An abnormally high glycogen content was detected in ΔsigBCE (SigD is active), while the carotenoid content became high in ΔsigCDE (SigB is active), indicating that SigB and SigD regulate the partitioning of carbon skeletons in low nitrogen. Long-term survival and recovery of the cells after nitrogen deficiency was strongly dependent on group 2 σ factors. The quadruple mutant and the ΔsigBDE strain (only SigC is active) recovered more slowly from nitrogen deficiency than the control strain, and ΔsigBCDE in particular lost viability during nitrogen starvation. Nitrogen deficiency-induced changes in the pigment content of the control strain recovered essentially in 1 d in nitrogen-replete medium, but little recovery occurred in ΔsigBCDE and ΔsigBDE.
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Affiliation(s)
- Taras Antal
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland Biological Faculty, Moscow State University, Vorobyevi Gory 119992, Moscow, Russia
| | - Juha Kurkela
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | | | - Anna Kårlund
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Kaisa Hakkila
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Esa Tyystjärvi
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Taina Tyystjärvi
- Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
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Koskinen S, Hakkila K, Gunnelius L, Kurkela J, Wada H, Tyystjärvi T. In vivorecruitment analysis and a mutant strain without any group 2 σ factor reveal roles of different σ factors in cyanobacteria. Mol Microbiol 2015; 99:43-54. [DOI: 10.1111/mmi.13214] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Satu Koskinen
- Department of Biochemistry; University of Turku; FIN-20014 Turku Finland
| | - Kaisa Hakkila
- Department of Biochemistry; University of Turku; FIN-20014 Turku Finland
| | - Liisa Gunnelius
- Department of Biochemistry; University of Turku; FIN-20014 Turku Finland
| | - Juha Kurkela
- Department of Biochemistry; University of Turku; FIN-20014 Turku Finland
| | - Hajime Wada
- Department of Life Sciences; University of Tokyo; Komaba 3-8-1, Meguro-ku Tokyo 153-8902 Japan
| | - Taina Tyystjärvi
- Department of Biochemistry; University of Turku; FIN-20014 Turku Finland
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Sandrini G, Cunsolo S, Schuurmans JM, Matthijs HCP, Huisman J. Changes in gene expression, cell physiology and toxicity of the harmful cyanobacterium Microcystis aeruginosa at elevated CO2. Front Microbiol 2015; 6:401. [PMID: 25999931 PMCID: PMC4419860 DOI: 10.3389/fmicb.2015.00401] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/17/2015] [Indexed: 12/31/2022] Open
Abstract
Rising CO2 concentrations may have large effects on aquatic microorganisms. In this study, we investigated how elevated pCO2 affects the harmful freshwater cyanobacterium Microcystis aeruginosa. This species is capable of producing dense blooms and hepatotoxins called microcystins. Strain PCC 7806 was cultured in chemostats that were shifted from low to high pCO2 conditions. This resulted in a transition from a C-limited to a light-limited steady state, with a ~2.7-fold increase of the cyanobacterial biomass and ~2.5-fold more microcystin per cell. Cells increased their chlorophyll a and phycocyanin content, and raised their PSI/PSII ratio at high pCO2. Surprisingly, cells had a lower dry weight and contained less carbohydrates, which might be an adaptation to improve the buoyancy of Microcystis when light becomes more limiting at high pCO2. Only 234 of the 4691 genes responded to elevated pCO2. For instance, expression of the carboxysome, RuBisCO, photosystem and C metabolism genes did not change significantly, and only a few N assimilation genes were expressed differently. The lack of large-scale changes in the transcriptome could suit a buoyant species that lives in eutrophic lakes with strong CO2 fluctuations very well. However, we found major responses in inorganic carbon uptake. At low pCO2, cells were mainly dependent on bicarbonate uptake, whereas at high pCO2 gene expression of the bicarbonate uptake systems was down-regulated and cells shifted to CO2 and low-affinity bicarbonate uptake. These results show that the need for high-affinity bicarbonate uptake systems ceases at elevated CO2. Moreover, the combination of an increased cyanobacterial abundance, improved buoyancy, and higher toxin content per cell indicates that rising atmospheric CO2 levels may increase the problems associated with the harmful cyanobacterium Microcystis in eutrophic lakes.
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Affiliation(s)
- Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Serena Cunsolo
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - J. Merijn Schuurmans
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
- Department of Aquatic Ecology, Netherlands Institute of EcologyWageningen, Netherlands
| | - Hans C. P. Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
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20
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Chukhutsina V, Bersanini L, Aro EM, van Amerongen H. Cyanobacterial flv4-2 Operon-Encoded Proteins Optimize Light Harvesting and Charge Separation in Photosystem II. MOLECULAR PLANT 2015; 8:747-61. [PMID: 25704162 DOI: 10.1016/j.molp.2014.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/09/2014] [Accepted: 12/21/2014] [Indexed: 05/11/2023]
Abstract
Photosystem II (PSII) complexes drive the water-splitting reaction necessary to transform sunlight into chemical energy. However, too much light can damage and disrupt PSII. In cyanobacteria, the flv4-2 operon encodes three proteins (Flv2, Flv4, and Sll0218), which safeguard PSII activity under air-level CO2 and in high light conditions. However, the exact mechanism of action of these proteins has not been clarified yet. We demonstrate that the PSII electron transfer properties are influenced by the flv4-2 operon-encoded proteins. Accelerated secondary charge separation kinetics was observed upon expression/overexpression of the flv4-2 operon. This is likely induced by docking of the Flv2/Flv4 heterodimer in the vicinity of the QB pocket of PSII, which, in turn, increases the QB redox potential and consequently stabilizes forward electron transfer. The alternative electron transfer route constituted by Flv2/Flv4 sequesters electrons from QB(-) guaranteeing the dissipation of excess excitation energy in PSII under stressful conditions. In addition, we demonstrate that in the absence of the flv4-2 operon-encoded proteins, about 20% of the phycobilisome antenna becomes detached from the reaction centers, thus decreasing light harvesting. Phycobilisome detachment is a consequence of a decreased relative content of PSII dimers, a feature observed in the absence of the Sll0218 protein.
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Affiliation(s)
- Volha Chukhutsina
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands; MicroSpectroscopy Centre, Wageningen University, 6703HA Wageningen, The Netherlands; BioSolarCells, P.O. Box 98, 6700AB Wageningen, The Netherlands
| | - Luca Bersanini
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands; MicroSpectroscopy Centre, Wageningen University, 6703HA Wageningen, The Netherlands; BioSolarCells, P.O. Box 98, 6700AB Wageningen, The Netherlands.
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21
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Gunnelius L, Kurkela J, Hakkila K, Koskinen S, Parikainen M, Tyystjärvi T. The ω subunit of RNA polymerase is essential for thermal acclimation of the cyanobacterium Synechocystis sp. PCC 6803. PLoS One 2014; 9:e112599. [PMID: 25386944 PMCID: PMC4227741 DOI: 10.1371/journal.pone.0112599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/09/2014] [Indexed: 01/26/2023] Open
Abstract
The rpoZ gene encodes the small ω subunit of RNA polymerase. A ΔrpoZ strain of the cyanobacterium Synechocystis sp. PCC 6803 grew well in standard conditions (constant illumination at 40 µmol photons m−2 s−1; 32°C; ambient CO2) but was heat sensitive and died at 40°C. In the control strain, 71 genes were at least two-fold up-regulated and 91 genes down-regulated after a 24-h treatment at 40°C, while in ΔrpoZ 394 genes responded to heat. Only 62 of these heat-responsive genes were similarly regulated in both strains, and 80% of heat-responsive genes were unique for ΔrpoZ. The RNA polymerase core and the primary σ factor SigA were down-regulated in the control strain at 40°C but not in ΔrpoZ. In accordance with reduced RNA polymerase content, the total RNA content of mild-heat-stress-treated cells was lower in the control strain than in ΔrpoZ. Light-saturated photosynthetic activity decreased more in ΔrpoZ than in the control strain upon mild heat stress. The amounts of photosystem II and rubisco decreased at 40°C in both strains while PSI and the phycobilisome antenna protein allophycocyanin remained at the same level as in standard conditions. The phycobilisome rod proteins, phycocyanins, diminished during the heat treatment in ΔrpoZ but not in the control strain, and the nblA1 and nblA2 genes (encode NblA proteins required for phycobilisome degradation) were up-regulated only in ΔrpoZ. Our results show that the ω subunit of RNAP is essential in heat stress because it is required for heat acclimation of diverse cellular processes.
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Affiliation(s)
- Liisa Gunnelius
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Juha Kurkela
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Kaisa Hakkila
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Satu Koskinen
- Department of Biochemistry, University of Turku, Turku, Finland
| | | | - Taina Tyystjärvi
- Department of Biochemistry, University of Turku, Turku, Finland
- * E-mail:
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Osanai T, Oikawa A, Iijima H, Kuwahara A, Asayama M, Tanaka K, Ikeuchi M, Saito K, Hirai MY. Metabolomic analysis reveals rewiring of Synechocystis sp. PCC 6803 primary metabolism by ntcA overexpression. Environ Microbiol 2014; 16:3304-17. [PMID: 25039649 DOI: 10.1111/1462-2920.12554] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 06/30/2014] [Indexed: 11/26/2022]
Abstract
NtcA is a cAMP receptor protein-type transcription factor conserved among cyanobacteria and is essential for gene expression in response to nitrogen status. NtcA has been widely studied; however, no metabolomic analysis has been conducted using the ntcA mutant. Here, we generated a strain that overexpresses ntcA in Synechocystis sp. PCC 6803, named NOX10, and performed physiological, transcriptomic and metabolomic analyses. NOX10 grew faster than the wild-type strain under photoautotrophic conditions, but slower under light-activated heterotrophic conditions. Transcriptome analysis revealed that the expression of genes related to primary metabolism was altered by ntcA overexpression particularly under nitrogen-depleted conditions. Metabolomic analysis revealed that metabolite levels in sugar, purine/pyrimidine nucleotide, organic acid and amino acid metabolism were widely altered by ntcA overexpression. The protein levels of nitrogen-regulated transcriptional regulators were altered by ntcA overexpression during nitrogen starvation. These results demonstrate the alteration of primary metabolism by genetic engineering of NtcA, and they contribute to the current understanding of metabolic regulation of unicellular cyanobacteria.
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Affiliation(s)
- Takashi Osanai
- RIKEN, Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan; Japan Science and Technology Agency (JST), PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
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23
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Overexpression of sigma factor SigB improves temperature and butanol tolerance of Synechocystis sp. PCC6803. J Biotechnol 2014; 182-183:54-60. [DOI: 10.1016/j.jbiotec.2014.04.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/17/2014] [Accepted: 04/25/2014] [Indexed: 11/21/2022]
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Schuurmans RM, Schuurmans JM, Bekker M, Kromkamp JC, Matthijs HC, Hellingwerf KJ. The redox potential of the plastoquinone pool of the cyanobacterium Synechocystis species strain PCC 6803 is under strict homeostatic control. PLANT PHYSIOLOGY 2014; 165:463-75. [PMID: 24696521 PMCID: PMC4012603 DOI: 10.1104/pp.114.237313] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A method is presented for rapid extraction of the total plastoquinone (PQ) pool from Synechocystis sp. strain PCC 6803 cells that preserves the in vivo plastoquinol (PQH2) to -PQ ratio. Cells were rapidly transferred into ice-cold organic solvent for instantaneous extraction of the cellular PQ plus PQH2 content. After high-performance liquid chromatography fractionation of the organic phase extract, the PQH2 content was quantitatively determined via its fluorescence emission at 330 nm. The in-cell PQH2-PQ ratio then followed from comparison of the PQH2 signal in samples as collected and in an identical sample after complete reduction with sodium borohydride. Prior to PQH2 extraction, cells from steady-state chemostat cultures were exposed to a wide range of physiological conditions, including high/low availability of inorganic carbon, and various actinic illumination conditions. Well-characterized electron-transfer inhibitors were used to generate a reduced or an oxidized PQ pool for reference. The in vivo redox state of the PQ pool was correlated with the results of pulse-amplitude modulation-based chlorophyll a fluorescence emission measurements, oxygen exchange rates, and 77 K fluorescence emission spectra. Our results show that the redox state of the PQ pool of Synechocystis sp. strain PCC 6803 is subject to strict homeostatic control (i.e. regulated between narrow limits), in contrast to the more dynamic chlorophyll a fluorescence signal.
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Hakkila K, Antal T, Rehman AU, Kurkela J, Wada H, Vass I, Tyystjärvi E, Tyystjärvi T. Oxidative stress and photoinhibition can be separated in the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:217-25. [DOI: 10.1016/j.bbabio.2013.11.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/09/2013] [Accepted: 11/15/2013] [Indexed: 01/15/2023]
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26
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Gunnelius L, Hakkila K, Kurkela J, Wada H, Tyystjärvi E, Tyystjärvi T. The omega subunit of the RNA polymerase core directs transcription efficiency in cyanobacteria. Nucleic Acids Res 2014; 42:4606-14. [PMID: 24476911 PMCID: PMC3985657 DOI: 10.1093/nar/gku084] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The eubacterial RNA polymerase core, a transcription machinery performing DNA-dependent RNA polymerization, consists of two α subunits and β, β' and ω subunits. An additional σ subunit is recruited for promoter recognition and transcription initiation. Cyanobacteria, a group of eubacteria characterized by oxygenic photosynthesis, have a unique composition of the RNA polymerase (RNAP) core due to splitting of the β' subunit to N-terminal γ and C-terminal β' subunits. The physiological roles of the small ω subunit of RNAP, encoded by the rpoZ gene, are not yet completely understood in any bacteria. We found that although ω is non-essential in cyanobacteria, it has a major impact on the overall gene expression pattern. In ΔrpoZ strain, recruitment of the primary σ factor into the RNAP holoenzyme is inefficient, which causes downregulation of highly expressed genes and upregulation of many low-expression genes. Especially, genes encoding proteins of photosynthetic carbon concentrating and carbon fixing complexes were down, and the ΔrpoZ mutant showed low light-saturated photosynthetic activity and accumulated photoprotective carotenoids and α-tocopherol. The results indicate that the ω subunit facilitates the association of the primary σ factor with the RNAP core, thereby allowing efficient transcription of highly expressed genes.
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Affiliation(s)
- Liisa Gunnelius
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland and Department of Life Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
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