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Zheng B, Du Y, Deng Y, Zhao T, Dong P, Shi J, Wu Z. Colonial morphology weakens the response of different inorganic carbon uptake systems to CO 2 levels in Microcystis population. HARMFUL ALGAE 2023; 128:102491. [PMID: 37714577 DOI: 10.1016/j.hal.2023.102491] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 09/17/2023]
Abstract
Rising atmospheric CO2 concentration negatively impacts aquatic ecosystems and may induce evolutionary changes in the CO2-concentrating mechanism (CCM) of cyanobacteria. As the most notorious freshwater cyanobacteria, Microcystis strains have high phenotypic plasticity to form colonies and blooms in lakes and reservoirs worldwide. However, phenotypic plasticity of Microcystis responses to elevated CO2 is still a major open question. Here, we studied how Microcystis strains with two genotype of inorganic carbon uptake systems, bicA and sbtA, and different colonial morphology response to 200 ppm, 400 ppm, and 800 ppm CO2 levels. The results revealed that sbtA genotypes showed significantly higher specific growth rates, Chl a concentration, and photosynthetic efficiency at 200 ppm CO2, whereas higher specific growth rates, Chl a concentration, and photosynthetic efficiency were found in bicA genotype at 800 ppm CO2. The highest values of specific growth rates, Chl a concentration, Fv/Fm, and maximal net photosynthesis (Pm) were observed in unicellular morphology, followed by small colony and large colonial morphology at all CO2 levels. The values of K0.5 (DIC), K0.5 (CO2), and K0.5 (HCO3-) in the large colonials increased with rising CO2 levels, but these values significantly decreased in the unicellular and small colonials. ANOSIM analysis indicated that colonial morphology reduced significantly inter-group differences between bicA and sbtA genotypes at all CO2 treatments. These results suggest that colonial morphology of Microcystis can weakens the response of different inorganic carbon uptake systems to CO2 levels. Moreover, phenotypic and genotypic plasticity is likely to broaden strongly the fitness of Microcystis from rising atmospheric CO2.
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Affiliation(s)
- Baohai Zheng
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
| | - Yuxin Du
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
| | - Yuting Deng
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
| | - Teng Zhao
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
| | - Peichang Dong
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
| | - Junqiong Shi
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
| | - Zhongxing Wu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China.
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Bongirwar R, Shukla P. Metabolic sink engineering in cyanobacteria: Perspectives and applications. BIORESOURCE TECHNOLOGY 2023; 379:128974. [PMID: 36990331 DOI: 10.1016/j.biortech.2023.128974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/24/2023] [Accepted: 03/25/2023] [Indexed: 05/03/2023]
Abstract
Recent advances in metabolic engineering have made cyanobacteria emerge as promising and attractive microorganisms for sustainable production, by exploiting their natural capability for producing metabolites. The potential of metabolically engineered cyanobacterium would depend on its source-sink balance in the same way as other phototrophs. In cyanobacteria, the amount of light energy harvested (Source) is incompletely utilized by the cell to fix carbon (sink) resulting in wastage of the absorbed energy causing photoinhibition and cellular damage leading to lowered photosynthetic efficiency. Although regulatory pathways like photo-acclimation and photoprotective processes can be helpful unfortunately they limit the cell's metabolic capacity. This review describes approaches for source-sink balance and engineering heterologous metabolic sinks in cyanobacteria for enhanced photosynthetic efficiency. The advances for engineering additional metabolic pathways in cyanobacteria are also described which will provide a better understanding of the cyanobacterial source-sink balance and approaches for efficient cyanobacterial strains for valuable metabolites.
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Affiliation(s)
- Riya Bongirwar
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India.
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3
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Shokravi S, Bahavar N. Growth and photosynthesis acclimated response of the cyanobacterium Fischerella sp. FS 18 exposed to extreme conditions: alkaline pH, limited irradiance, and carbon dioxide concentration. Extremophiles 2021; 25:493-500. [PMID: 34545451 DOI: 10.1007/s00792-021-01244-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/06/2021] [Indexed: 11/29/2022]
Abstract
The true-branching heterocystous cyanobacterium Fischerella sp. FS 18 is widely distributed in paddy fields (North) and petroleum polluted soils (South) in Iran. This investigation tested the hypothesis that the cyanobacterium can acclimatize under the combined effect of extreme environmental conditions. Here, we analysed the physiological response of the cyanobacterium under extremely limited irradiance (2 μmol photon m-2 s-1); limited carbon dioxide concentration (no aeration) at alkaline pHs (9 and 11) for up to 96 h. When the cyanobacterium was exposed to these extreme conditions at pH 11, we observed a decline in growth, oxygen liberation, photosystems ratio, chlorophyll a, and phycobilisomes activity compared to pH 9 after 24 h. Besides, we registered a significant decrease in maximum photochemical efficiency and activity of photosystem II at pH 11. The comparative single-cell study revealed that pH 9 caused higher efficiency of photosystem II and I, while increasing alkalinity pH 11 led to disturbed phycobilisomes activity after 24 h. This strain was able to recover its structures after 96 h. In addition, spectroscopy analyses revealed the presence of the Mycosporine-like amino acid at pH 9.
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Affiliation(s)
- Shadman Shokravi
- Department of Biology, Gorgan Branch, Islamic Azad University, Gorgan, Iran.
| | - Nadia Bahavar
- Plant Physiology Laboratory, Bioscience Faculty, Universidad Autónoma de Barcelona (UAB), 08193, Belletarra, Spain.
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Stable Reference Gene Selection for RT-qPCR Analysis in Synechococcus elongatus PCC 7942 under Abiotic Stresses. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7630601. [PMID: 31139651 PMCID: PMC6500708 DOI: 10.1155/2019/7630601] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/15/2019] [Accepted: 04/07/2019] [Indexed: 12/27/2022]
Abstract
Synechococcus elongatus PCC 7942 (S. elongatus PCC 7942) is a model cyanobacteria species for circadian clock mechanism studies. It has also been widely used as a bioreactor to produce biofuels and other metabolic products. Quantitative real-time PCR (qPCR) technology is the most commonly used method for studying the expression of specific genes, in which the relative expression level of target genes is calibrated by stably expressed internal reference genes. In this work, we examined the expression of nine candidate reference genes in time-course samples of S. elongatus PCC 7942 under no treatment (control), NaCl-stress conditions, H2O2-stress conditions, and high light-stress conditions. Based on the qPCR amplification parameters, the stability ranking of these candidate reference genes was established by three statistical software programs, geNorm, NormFinder, and BestKeeper. Considering all the stress conditions or high light stress alone, the results showed that the combination of prs and secA was the best choice for the double reference gene calibration method by qPCR. The combination of secA and ppc, rimM and rnpA, rnpA, and ilvD was most stable under no treatment, NaCl-stress conditions, and H2O2-stress conditions, respectively. rimM was stable under only special conditions and should be carefully chosen. 16S and rnpB were not suitable as internal reference genes for S. elongatus PCC 7942 qPCR experiments under all experimental conditions. To validate the above results, a cyanobacterial core clock gene, kaiC, was used to evaluate the actual performance of the optimized reference genes by qPCR, as well as the worst reference genes under different stress conditions. The results indicated that the best reference gene yielded more accurate calibration results for qPCR experiments carried out in S. elongatus PCC 7942 time-course samples.
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Abstract
Rubisco is often claimed to be the most abundant protein on Earth, yet the quantitative evidence to support the estimate of its global mass are scarce. Here we provide a robust and detailed estimate of the global mass of Rubisco, which is an order of magnitude larger than previous estimates. We use this estimate to derive the time-average rate of terrestrial and marine Rubisco and show that they are, respectively, 100-fold and sevenfold lower than the in vitro measured kcat of Rubisco at 25 °C. Photosynthetic carbon assimilation enables energy storage in the living world and produces most of the biomass in the biosphere. Rubisco (d-ribulose 1,5-bisphosphate carboxylase/oxygenase) is responsible for the vast majority of global carbon fixation and has been claimed to be the most abundant protein on Earth. Here we provide an updated and rigorous estimate for the total mass of Rubisco on Earth, concluding it is ≈0.7 Gt, more than an order of magnitude higher than previously thought. We find that >90% of Rubisco enzymes are found in the ≈2 × 1014 m2 of leaves of terrestrial plants, and that Rubisco accounts for ≈3% of the total mass of leaves, which we estimate at ≈30 Gt dry weight. We use our estimate for the total mass of Rubisco to derive the effective time-averaged catalytic rate of Rubisco of ≈0.03 s−1 on land and ≈0.6 s−1 in the ocean. Compared with the maximal catalytic rate observed in vitro at 25 °C, the effective rate in the wild is ≈100-fold slower on land and sevenfold slower in the ocean. The lower ambient temperature, and Rubisco not working at night, can explain most of the difference from laboratory conditions in the ocean but not on land, where quantification of many more factors on a global scale is needed. Our analysis helps sharpen the dramatic difference between laboratory and wild environments and between the terrestrial and marine environments.
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Luimstra VM, Schuurmans JM, Verschoor AM, Hellingwerf KJ, Huisman J, Matthijs HCP. Blue light reduces photosynthetic efficiency of cyanobacteria through an imbalance between photosystems I and II. PHOTOSYNTHESIS RESEARCH 2018; 138:177-189. [PMID: 30027501 PMCID: PMC6208612 DOI: 10.1007/s11120-018-0561-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/12/2018] [Indexed: 05/29/2023]
Abstract
Several studies have described that cyanobacteria use blue light less efficiently for photosynthesis than most eukaryotic phototrophs, but comprehensive studies of this phenomenon are lacking. Here, we study the effect of blue (450 nm), orange (625 nm), and red (660 nm) light on growth of the model cyanobacterium Synechocystis sp. PCC 6803, the green alga Chlorella sorokiniana and other cyanobacteria containing phycocyanin or phycoerythrin. Our results demonstrate that specific growth rates of the cyanobacteria were similar in orange and red light, but much lower in blue light. Conversely, specific growth rates of the green alga C. sorokiniana were similar in blue and red light, but lower in orange light. Oxygen production rates of Synechocystis sp. PCC 6803 were five-fold lower in blue than in orange and red light at low light intensities but approached the same saturation level in all three colors at high light intensities. Measurements of 77 K fluorescence emission demonstrated a lower ratio of photosystem I to photosystem II (PSI:PSII ratio) and relatively more phycobilisomes associated with PSII (state 1) in blue light than in orange and red light. These results support the hypothesis that blue light, which is not absorbed by phycobilisomes, creates an imbalance between the two photosystems of cyanobacteria with an energy excess at PSI and a deficiency at the PSII-side of the photosynthetic electron transfer chain. Our results help to explain why phycobilisome-containing cyanobacteria use blue light less efficiently than species with chlorophyll-based light-harvesting antennae such as Prochlorococcus, green algae and terrestrial plants.
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Affiliation(s)
- Veerle M Luimstra
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94248, 1090 GE, Amsterdam, The Netherlands
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - J Merijn Schuurmans
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94248, 1090 GE, Amsterdam, The Netherlands
| | - Antonie M Verschoor
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
- KWR Watercycle Research Institute, PO Box 1072, 3430 BB, Nieuwegein, The Netherlands
| | - Klaas J Hellingwerf
- Swammerdam Institute for Life Sciences, University of Amsterdam, PO Box 94248, 1090 GE, Amsterdam, The Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94248, 1090 GE, Amsterdam, The Netherlands.
| | - Hans C P Matthijs
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94248, 1090 GE, Amsterdam, The Netherlands
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Cellular trade-offs and optimal resource allocation during cyanobacterial diurnal growth. Proc Natl Acad Sci U S A 2017; 114:E6457-E6465. [PMID: 28720699 DOI: 10.1073/pnas.1617508114] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cyanobacteria are an integral part of Earth's biogeochemical cycles and a promising resource for the synthesis of renewable bioproducts from atmospheric CO2 Growth and metabolism of cyanobacteria are inherently tied to the diurnal rhythm of light availability. As yet, however, insight into the stoichiometric and energetic constraints of cyanobacterial diurnal growth is limited. Here, we develop a computational framework to investigate the optimal allocation of cellular resources during diurnal phototrophic growth using a genome-scale metabolic reconstruction of the cyanobacterium Synechococcus elongatus PCC 7942. We formulate phototrophic growth as an autocatalytic process and solve the resulting time-dependent resource allocation problem using constraint-based analysis. Based on a narrow and well-defined set of parameters, our approach results in an ab initio prediction of growth properties over a full diurnal cycle. The computational model allows us to study the optimality of metabolite partitioning during diurnal growth. The cyclic pattern of glycogen accumulation, an emergent property of the model, has timing characteristics that are in qualitative agreement with experimental findings. The approach presented here provides insight into the time-dependent resource allocation problem of phototrophic diurnal growth and may serve as a general framework to assess the optimality of metabolic strategies that evolved in phototrophic organisms under diurnal conditions.
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Pierobon SC, Riordon J, Nguyen B, Ooms MD, Sinton D. Periodic harvesting of microalgae from calcium alginate hydrogels for sustained high-density production. Biotechnol Bioeng 2017; 114:2023-2031. [DOI: 10.1002/bit.26325] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/09/2017] [Accepted: 04/25/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Scott C. Pierobon
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy; University of Toronto; 5 King's College Road Toronto ON M5S 3G8 Canada
| | - Jason Riordon
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy; University of Toronto; 5 King's College Road Toronto ON M5S 3G8 Canada
| | - Brian Nguyen
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy; University of Toronto; 5 King's College Road Toronto ON M5S 3G8 Canada
| | - Matthew D. Ooms
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy; University of Toronto; 5 King's College Road Toronto ON M5S 3G8 Canada
| | - David Sinton
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy; University of Toronto; 5 King's College Road Toronto ON M5S 3G8 Canada
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Arai S, Hayashihara K, Kanamoto Y, Shimizu K, Hirokawa Y, Hanai T, Murakami A, Honda H. Alcohol‐tolerant mutants of cyanobacterium
Synechococcus elongatus
PCC 7942 obtained by single‐cell mutant screening system. Biotechnol Bioeng 2017; 114:1771-1778. [DOI: 10.1002/bit.26307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/02/2017] [Accepted: 04/04/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Sayuri Arai
- Department of BiotechnologyGraduate School of EngineeringNagoya UniversityFuro‐choChikusa‐kuNagoyaAichi464‐8603Japan
| | | | - Yuki Kanamoto
- Kobe University Research Center for Inland SeasAwajiHyogoJapan
| | - Kazunori Shimizu
- Department of BiotechnologyGraduate School of EngineeringNagoya UniversityFuro‐choChikusa‐kuNagoyaAichi464‐8603Japan
| | - Yasutaka Hirokawa
- Laboratory for BioinformaticsGraduate School of Systems Life SciencesKyushu UniversityHigashi‐kuFukuokaJapan
| | - Taizo Hanai
- Laboratory for BioinformaticsGraduate School of Systems Life SciencesKyushu UniversityHigashi‐kuFukuokaJapan
| | - Akio Murakami
- Kobe University Research Center for Inland SeasAwajiHyogoJapan
| | - Hiroyuki Honda
- Department of BiotechnologyGraduate School of EngineeringNagoya UniversityFuro‐choChikusa‐kuNagoyaAichi464‐8603Japan
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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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Pierobon SC, Riordon J, Nguyen B, Sinton D. Breathable waveguides for combined light and CO2 delivery to microalgae. BIORESOURCE TECHNOLOGY 2016; 209:391-396. [PMID: 26996260 DOI: 10.1016/j.biortech.2016.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 02/27/2016] [Accepted: 03/01/2016] [Indexed: 06/05/2023]
Abstract
Suboptimal light and chemical distribution (CO2, O2) in photobioreactors hinder phototrophic microalgal productivity and prevent economically scalable production of biofuels and bioproducts. Current strategies that improve illumination in reactors negatively impact chemical distribution, and vice versa. In this work, an integrated illumination and aeration approach is demonstrated using a gas-permeable planar waveguide that enables combined light and chemical distribution. An optically transparent cellulose acetate butyrate (CAB) slab is used to supply both light and CO2 at various source concentrations to cyanobacteria. The breathable waveguide architecture is capable of cultivating microalgae with over double the growth as achieved with impermeable waveguides.
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Affiliation(s)
- Scott C Pierobon
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada
| | - Jason Riordon
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada
| | - Brian Nguyen
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada
| | - David Sinton
- Department of Mechanical & Industrial Engineering and Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada.
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Jung JH, Lee KS, Im S, Destgeer G, Ha BH, Park J, Sung HJ. Photosynthesis of cyanobacteria in a miniaturized optofluidic waveguide platform. RSC Adv 2016. [DOI: 10.1039/c5ra24344k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We investigated the effect of increasing the optical penetration length, inside polydimethylsiloxane (PDMS)-based photobioreactors (PBRs), upon the photosynthetic cell growth of cyanobacteria.
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Affiliation(s)
- Jin Ho Jung
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Kang Soo Lee
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Sunghyuk Im
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Ghulam Destgeer
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Byung Hang Ha
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Jinsoo Park
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Hyung Jin Sung
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
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14
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Graham PJ, Riordon J, Sinton D. Microalgae on display: a microfluidic pixel-based irradiance assay for photosynthetic growth. LAB ON A CHIP 2015; 15:3116-24. [PMID: 26085371 DOI: 10.1039/c5lc00527b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Microalgal biofuel is an emerging sustainable energy resource. Photosynthetic growth is heavily dependent on irradiance, therefore photobioreactor design optimization requires comprehensive screening of irradiance variables, such as intensity, time variance and spectral composition. Here we present a microfluidic irradiance assay which leverages liquid crystal display technology to provide multiplexed screening of irradiance conditions on growth. An array of 238 microreactors are operated in parallel with identical chemical environments. The approach is demonstrated by performing three irradiance assays. The first assay evaluates the effect of intensity on growth, quantifying saturating intensity. The second assay quantifies the influence of time-varied intensity and the threshold frequency for growth. Lastly, the coupled influence of red-blue spectral composition and intensity is assessed. Each multiplexed assay is completed within three days. In contrast, completing the same number of experiments using conventional incubation flasks would require several years. Not only does our approach enable more rapid screening, but the short optical path avoids self-shading issues inherent to flask based systems.
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Affiliation(s)
- Percival J Graham
- Department of Mechanical and Industrial Engineering and Institute for Sustainable Energy, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada.
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15
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Burnap RL, Hagemann M, Kaplan A. Regulation of CO2 Concentrating Mechanism in Cyanobacteria. Life (Basel) 2015; 5:348-71. [PMID: 25636131 PMCID: PMC4390856 DOI: 10.3390/life5010348] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/15/2015] [Accepted: 01/21/2015] [Indexed: 12/31/2022] Open
Abstract
In this chapter, we mainly focus on the acclimation of cyanobacteria to the changing ambient CO2 and discuss mechanisms of inorganic carbon (Ci) uptake, photorespiration, and the regulation among the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. The structural components for several of the transport and uptake mechanisms are described and the progress towards elucidating their regulation is discussed in the context of studies, which have documented metabolomic changes in response to changes in Ci availability. Genes for several of the transport and uptake mechanisms are regulated by transcriptional regulators that are in the LysR-transcriptional regulator family and are known to act in concert with small molecule effectors, which appear to be well-known metabolites. Signals that trigger changes in gene expression and enzyme activity correspond to specific "regulatory metabolites" whose concentrations depend on the ambient Ci availability. Finally, emerging evidence for an additional layer of regulatory complexity involving small non-coding RNAs is discussed.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Martin Hagemann
- Institute Biosciences, Department Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, Rostock D-18059, Germany.
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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16
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Bernstein HC, Konopka A, Melnicki MR, Hill EA, Kucek LA, Zhang S, Shen G, Bryant DA, Beliaev AS. Effect of mono- and dichromatic light quality on growth rates and photosynthetic performance of Synechococcus sp. PCC 7002. Front Microbiol 2014; 5:488. [PMID: 25285095 PMCID: PMC4168726 DOI: 10.3389/fmicb.2014.00488] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 08/30/2014] [Indexed: 01/30/2023] Open
Abstract
Synechococcus sp. PCC 7002 was grown to steady state in optically thin turbidostat cultures under conditions for which light quantity and quality was systematically varied by modulating the output of narrow-band LEDs. Cells were provided photons absorbed primarily by chlorophyll (680 nm) or phycocyanin (630 nm) as the organism was subjected to four distinct mono- and dichromatic regimes. During cultivation with dichromatic light, growth rates were generally proportional to the total incident irradiance at values <275 μmol photons m(-2) · s(-1) and were not affected by the ratio of 630:680 nm wavelengths. Notably, under monochromatic light conditions, cultures exhibited similar growth rates only when they were irradiated with 630 nm light; cultures irradiated with only 680 nm light grew at rates that were 60-70% of those under other light quality regimes at equivalent irradiances. The functionality of photosystem II and associated processes such as maximum rate of photosynthetic electron transport, rate of cyclic electron flow, and rate of dark respiration generally increased as a function of growth rate. Nonetheless, some of the photophysiological parameters measured here displayed distinct patterns with respect to growth rate of cultures adapted to a single wavelength including phycobiliprotein content, which increased under severely light-limited growth conditions. Additionally, the ratio of photosystem II to photosystem I increased ~40% over the range of growth rates, although cells grown with 680 nm light only had the highest ratios. These results suggest the presence of effective mechanisms which allow acclimation of Synechococcus sp. PCC 7002 acclimation to different irradiance conditions.
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Affiliation(s)
- Hans C. Bernstein
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
- Chemical and Biological Signature Science, Pacific Northwest National LaboratoryRichland, WA, USA
| | - Allan Konopka
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
- Department of Biological Sciences, Purdue UniversityW. Lafayette, IN, USA
| | - Matthew R. Melnicki
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
| | - Eric A. Hill
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
| | - Leo A. Kucek
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
| | - Shuyi Zhang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, USA
| | - Gaozhong Shen
- Department of Biological Sciences, Purdue UniversityW. Lafayette, IN, USA
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, USA
- Department of Chemistry and Biochemistry, Montana State UniversityBozeman, MT, USA
| | - Alexander S. Beliaev
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
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Pierangelini M, Stojkovic S, Orr PT, Beardall J. Elevated CO2 causes changes in the photosynthetic apparatus of a toxic cyanobacterium, Cylindrospermopsis raciborskii. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:1091-1098. [PMID: 24878143 DOI: 10.1016/j.jplph.2014.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Revised: 04/11/2014] [Accepted: 04/12/2014] [Indexed: 06/03/2023]
Abstract
We studied the physiological acclimation of growth, photosynthesis and CO2-concentrating mechanism (CCM) in Cylindrospermopsis raciborskii exposed to low (present day; L-CO2) and high (1300ppm; H-CO2) pCO2. Results showed that under H-CO2 the cell specific division rate (μc) was higher and the CO2- and light-saturated photosynthetic rates (Vmax and Pmax) doubled. The cells' photosynthetic affinity for CO2 (K0.5CO2) was halved compared to L-CO2 cultures. However, no significant differences were found in dark respiration rates (Rd), pigment composition and light harvesting efficiency (α). In H-CO2 cells, non-photochemical quenching (NPQ), associated with state transitions of the electron transport chain (ETC), was negligible. Simultaneously, a reorganisation of PSII features including antenna connectivity (JconPSIIα), heterogeneity (PSIIα/β) and effective absorption cross sectional area (σPSIIα/β) was observed. In relation to different activities of the CCM, our findings suggest that for cells grown under H-CO2: (1) there is down-regulation of CCM activity; (2) the ability of cells to use the harvested light energy is altered; (3) the occurrence of state transitions is likely to be associated with changes of electron flow (cyclic vs linear) through the ETC; (4) changes in PSII characteristics are important in regulating state transitions.
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Affiliation(s)
- Mattia Pierangelini
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia.
| | - Slobodanka Stojkovic
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia; CSIRO Marine and Atmospheric Research, Hobart, Tasmania, Australia
| | - Philip T Orr
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia; Seqwater, PO Box 16146, City East 4002, Queensland, Australia
| | - John Beardall
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia
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18
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Kalontarov M, Doud DFR, Jung EE, Angenent LT, Erickson D. Hollow fibre membrane arrays for CO2delivery in microalgae photobioreactors. RSC Adv 2014. [DOI: 10.1039/c3ra45087b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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19
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Kirchman DL, Hanson TE. Bioenergetics of photoheterotrophic bacteria in the oceans. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:188-199. [PMID: 23584962 DOI: 10.1111/j.1758-2229.2012.00367.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/26/2012] [Accepted: 06/28/2012] [Indexed: 06/02/2023]
Abstract
Photoheterotrophic microbes, such as proteorhodopsin (PR)-based phototrophic (PRP) and aerobic anoxygenic phototrophic (AAP) bacteria, are well known to be abundant in the oceans, potentially playing unique roles in biogeochemical cycles. However, the contribution of phototrophy to the energy requirements of these bacteria has not been quantitatively examined to date. To better understand the implications of photoheterophy in the oceans, we calculated energy benefits and costs of phototrophy and compared net benefits with maintenance costs. Benefits depend on the number of photosynthetic units (PSUs), absorption cross-section area of each PSU as function of wavelength, the in situ light quality, and the energy yield per absorbed photon. For costs we considered the energy required for the synthesis of pigments, amino acids and proteins in each PSU. Our calculations indicate that AAP bacteria harvest more light energy than do PRP bacteria, but the costs of phototrophy are much higher for AAP bacteria. Still, the net energy gained by AAP bacteria is often sufficient to meet maintenance costs, while that is not the case for PRP bacteria except with high light intensities and large numbers of proteorhodopsin molecules per cell. The low costs and simplicity of PR-based phototrophy explain the high abundance of proteorhodopsin genes in the oceans. However, even for AAP bacteria, the net energy yield of phototrophy is apparently too low to influence the distribution of photoheterotrophic bacteria among various marine systems.
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Affiliation(s)
- David L Kirchman
- School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA.
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20
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Kalontarov M, Doud DFR, Jung EE, Angenent LT, Erickson D. In situ hollow fiber membrane facilitated CO2 delivery to a cyanobacterium for enhanced productivity. RSC Adv 2013. [DOI: 10.1039/c3ra40454d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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21
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Xu J, Gao K. Future CO2-induced ocean acidification mediates the physiological performance of a green tide alga. PLANT PHYSIOLOGY 2012; 160:1762-9. [PMID: 23129205 PMCID: PMC3510108 DOI: 10.1104/pp.112.206961] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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22
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Pérez G, Doldán S, Borsani O, Irisarri P. Differential Response to Moderate UV-B Irradiation of Two Heterocystous Cyanobacteria Isolated from a Temperate Ricefield. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/aim.2012.21006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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Fukuzawa H, Ogawa T, Kaplan A. The Uptake of CO2 by Cyanobacteria and Microalgae. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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24
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Ooms MD, Sieben VJ, Pierobon SC, Jung EE, Kalontarov M, Erickson D, Sinton D. Evanescent photosynthesis: exciting cyanobacteria in a surface-confined light field. Phys Chem Chem Phys 2012; 14:4817-23. [DOI: 10.1039/c2cp40271h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Levitan O, Kranz SA, Spungin D, Prásil O, Rost B, Berman-Frank I. Combined effects of CO2 and light on the N2-fixing cyanobacterium Trichodesmium IMS101: a mechanistic view. PLANT PHYSIOLOGY 2010; 154:346-56. [PMID: 20625002 PMCID: PMC2938161 DOI: 10.1104/pp.110.159285] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The marine diazotrophic cyanobacterium Trichodesmium responds to elevated atmospheric CO(2) partial pressure (pCO(2)) with higher N(2) fixation and growth rates. To unveil the underlying mechanisms, we examined the combined influence of pCO(2) (150 and 900 microatm) and light (50 and 200 micromol photons m(-2) s(-1)) on Trichodesmium IMS101. We expand on a complementary study that demonstrated that while elevated pCO(2) enhanced N(2) fixation and growth, oxygen evolution and carbon fixation increased mainly as a response to high light. Here, we investigated changes in the photosynthetic fluorescence parameters of photosystem II, in ratios of the photosynthetic units (photosystem I:photosystem II), and in the pool sizes of key proteins involved in the fixation of carbon and nitrogen as well as their subsequent assimilation. We show that the combined elevation in pCO(2) and light controlled the operation of the CO(2)-concentrating mechanism and enhanced protein activity without increasing their pool size. Moreover, elevated pCO(2) and high light decreased the amounts of several key proteins (NifH, PsbA, and PsaC), while amounts of AtpB and RbcL did not significantly change. Reduced investment in protein biosynthesis, without notably changing photosynthetic fluxes, could free up energy that can be reallocated to increase N(2) fixation and growth at elevated pCO(2) and light. We suggest that changes in the redox state of the photosynthetic electron transport chain and posttranslational regulation of key proteins mediate the high flexibility in resources and energy allocation in Trichodesmium. This strategy should enable Trichodesmium to flourish in future surface oceans characterized by elevated pCO(2), higher temperatures, and high light.
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Affiliation(s)
- Orly Levitan
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel.
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26
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The evolution of inorganic carbon concentrating mechanisms in photosynthesis. Philos Trans R Soc Lond B Biol Sci 2008; 363:2641-50. [PMID: 18487130 PMCID: PMC2606764 DOI: 10.1098/rstb.2008.0020] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Inorganic carbon concentrating mechanisms (CCMs) catalyse the accumulation of CO(2) around rubisco in all cyanobacteria, most algae and aquatic plants and in C(4) and crassulacean acid metabolism (CAM) vascular plants. CCMs are polyphyletic (more than one evolutionary origin) and involve active transport of HCO(3)(-), CO(2) and/or H(+), or an energized biochemical mechanism as in C(4) and CAM plants. While the CCM in almost all C(4) plants and many CAM plants is constitutive, many CCMs show acclimatory responses to variations in the supply of not only CO(2) but also photosynthetically active radiation, nitrogen, phosphorus and iron. The evolution of CCMs is generally considered in the context of decreased CO(2) availability, with only a secondary role for increasing O(2). However, the earliest CCMs may have evolved in oxygenic cyanobacteria before the atmosphere became oxygenated in stromatolites with diffusion barriers around the cells related to UV screening. This would decrease CO(2) availability to cells and increase the O(2) concentration within them, inhibiting rubisco and generating reactive oxygen species, including O(3).
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27
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Raven JA, Giordano M, Beardall J. Insights into the evolution of CCMs from comparisons with other resource acquisition and assimilation processes. PHYSIOLOGIA PLANTARUM 2008; 133:4-14. [PMID: 18405331 DOI: 10.1111/j.1399-3054.2007.01024.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Regarding inorganic carbon as 'just another' chemical resource used in the growth of aquatic photolithotrophs, we ask three questions and then attempt to answer them. (1) How common are catalysed chemical changes of the resource outside the cell, and accumulation of the resource inside the cell prior to assimilation, for the diverse chemical resources used? (2) Do acquisition and assimilation meet evolutionary optimality criteria with respect to the use of other resources? (3) Are there clues to the evolutionary origin of inorganic carbon concentrating mechanism (CCMs) in the mechanisms of acquisition of other resources and vice versa? Evidence considered includes molecular genetic similarities between CCM components and components of other resource acquisition mechanisms, and palaeogeochemical evidence on the timing of restrictions on the availability of the resources such that extracellular transformation of materials, and their accumulation within cells prior to assimilation, are needed. Provisional answers to the questions are as follows: (1) Many common chemical resources other than inorganic carbon are subject to extracellular chemical conversion and/or accumulation prior to assimilation, e.g. ammonium, nitrate, urea, amino acids, organic and inorganic phosphate and iron; (2) There is some evidence for optimality of CCMs and of less complex resource acquisition processes, exemplified by NH(4)(+) entry and assimilation, though many more data are needed and (3) There are molecular genetic similarities between CCM components and transporters for other solutes and components of respiratory NADH dehydrogenases that are consistent with their use in CCMs representing a derived evolutionary state. Palaeogeochemical evidence suggests that CCMs evolved later than did at least some of the extracellular chemical transformation and/or accumulation mechanisms for other resources.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at SCRI, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom.
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28
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Losciale P, Oguchi R, Hendrickson L, Hope AB, Corelli-Grappadelli L, Chow WS. A rapid, whole-tissue determination of the functional fraction of PSII after photoinhibition of leaves based on flash-induced P700 redox kinetics. PHYSIOLOGIA PLANTARUM 2008; 132:23-32. [PMID: 18251867 DOI: 10.1111/j.1399-3054.2007.01000.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Assaying the number of functional PSII complexes by the oxygen yield from leaf tissue per saturating, single-turnover flash, assuming that each functional PSII evolves one oxygen molecule after four flashes, is one of the most direct methods but time-consuming. The ratio of variable to maximum Chl fluorescence yield (F(v)/F(m)) in leaves can be correlated with the oxygen yield per flash during a progressive loss of PSII activity associated with high-light stress and is rapid and non-intrusive, but suffers from being representative of chloroplasts near the measured leaf surface; consequently, the exact correlation depends on the internal leaf structure and on which leaf surface is being measured. Our results show that the average F(v)/F(m) of the adaxial and abaxial surfaces has a reasonable linear correlation with the oxygen yield per flash after varied extents of photoinactivation of PSII. However, we obtained an even better linear correlation between (1) the integrated, transient electron flow (Sigma) to P700+, the dimeric Chl cation in PSI, after superimposing a single-turnover flash on steady background far-red light and (2) the relative oxygen yield per flash. Leaves of C3 and C4 plants, woody and herbaceous species, wild-type and a Chl-b-less mutant, and monocot and dicot plants gave a single straight line, which seems to be a universal relation for predicting the relative oxygen yield per flash from Sigma. Measurement of Sigma is non-intrusive, representative of the whole leaf tissue, rapid and applicable to attached leaves; it may even be applicable in the field.
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Affiliation(s)
- Pasquale Losciale
- Photobioenergetics Group, Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory 0200, Australia
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29
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Jähnichen S, Ihle T, Petzoldt T, Benndorf J. Impact of inorganic carbon availability on microcystin production by Microcystis aeruginosa PCC 7806. Appl Environ Microbiol 2007; 73:6994-7002. [PMID: 17827326 PMCID: PMC2074933 DOI: 10.1128/aem.01253-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Batch culture experiments with the cyanobacterium Microcystis aeruginosa PCC 7806 were performed in order to test the hypothesis that microcystins (MCYSTs) are produced in response to a relative deficiency of intracellular inorganic carbon (C(i,i)). In the first experiment, MCYST production was studied under increased C(i,i) deficiency conditions, achieved by restricting sodium-dependent bicarbonate uptake through replacement of sodium bicarbonate in the medium with its potassium analog. The same experimental approach was used in a second experiment to compare the response of the wild-type strain M. aeruginosa PCC 7806 with its mcyB mutant, which lacks the ability to produce MCYSTs. In a third experiment, the impact of varying the C(i,i) status on MCYST production was examined without suppressing the sodium-dependent bicarbonate transporter; instead, a detailed investigation of a dark-light cycle was performed. In all experiments, a relative C(i,i) deficiency was indicated by an elevated variable fluorescence signal and led to enhanced phycocyanin cell quotas. Higher MCYST cell quotas (in the first and third experiments) and increased total (intracellular plus extracellular) MCYST production (in the first experiment) were detected with increased C(i,i) deficiency. Furthermore, the MCYST-producing wild-type strain and its mcyB mutant showed basically the same response to restrained inorganic carbon uptake, with elevated variable fluorescence and phycocyanin cell quotas with increased C(i,i) deficiency. The response of the wild type, however, was distinctly stronger and also included elevated chlorophyll a cell quotas. These differences indicate the limited ability of the mutant to adapt to low-C(i,i) conditions. We concluded that MCYSTs may be involved in enhancing the efficiency of the adaptation of the photosynthetic apparatus to fluctuating inorganic carbon conditions in cyanobacterial cells.
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Affiliation(s)
- Sabine Jähnichen
- Dresden University of Technology, Institute of Hydrobiology, 01062 Dresden, Germany.
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30
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Bouchard JN, Roy S, Campbell DA. UVB Effects on the Photosystem II-D1 Protein of Phytoplankton and Natural Phytoplankton Communities. Photochem Photobiol 2006; 82:936-51. [PMID: 16620154 DOI: 10.1562/2005-08-31-ir-666] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The reaction center of photosystem II is susceptible to photodamage. In particular the D1 protein located in the photosystem II core has a rapid, light-dependent turnover termed the photosystem II repair cycle that, under illumination, degrades and resynthesizes D1 protein to limit accumulation of photodamaged photosystem II. Most studies concerning the effects of UVB (280-320 nm) on this cycle have been on cyanobacteria or specific phytoplankton species rather than on natural communities of phytoplankton. During a 5-year multidisciplinary project on the effects of UV radiation (200-400 nm) on natural systems, the effects of UVB on the D1 protein of natural phytoplankton communities were assessed. This review provides an overview of photoinhibitory effects of light on cultured and natural phytoplankton, with an emphasis on the interrelation of UVB exposure, D1 protein degradation and the repair of photosystem II through D1 resynthesis. Although the UVB component of the solar spectrum contributes to the primary photoinactivation of photosystem II, we conclude that, in natural communities, inhibition of the rate of the photosystem II repair cycle is a more important influence of UVB on primary productivity. Indeed, exposing tropical and temperate phytoplankton communities to supplemented UVB had more inhibitory effect on D1 synthesis than on the D1 degradation process itself. However, the rate of net D1 damage was faster for the tropical communities, likely because of the effects of high ambient light and water temperature on mechanisms of protein degradation and synthesis.
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Affiliation(s)
- Josée Nina Bouchard
- Institut des Sciences de la Mer de Rimouski, Université du Québec a Rimouski, Canada
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31
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Mommer L, Pons TL, Visser EJW. Photosynthetic consequences of phenotypic plasticity in response to submergence: Rumex palustris as a case study. JOURNAL OF EXPERIMENTAL BOTANY 2006; 57:283-90. [PMID: 16291797 DOI: 10.1093/jxb/erj015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Survival and growth of terrestrial plants is negatively affected by complete submergence. This is mainly the result of hampered gas exchange between plants and their environment, since gas diffusion is severely reduced in water compared with air, resulting in O2 deficits which limit aerobic respiration. The continuation of photosynthesis could probably alleviate submergence-stress in terrestrial plants, but its potential under water will be limited as the availability of CO2 is hampered. Several submerged terrestrial plant species, however, express plastic responses of the shoot which may reduce gas diffusion resistance and enhance benefits from underwater photosynthesis. In particular, the plasticity of the flooding-tolerant terrestrial species Rumex palustris turned out to be remarkable, making it a model species suitable for the study of these responses. During submergence, the morphology and anatomy of newly developed leaves changed: 'aquatic' leaves were thinner and had thinner cuticles. As a consequence, internal O2 concentrations and underwater CO2 assimilation rates were higher at the prevailing low CO2 concentrations in water. Compared with heterophyllous amphibious plant species, underwater photosynthesis rates of terrestrial plants may be very limited, but the effects of underwater photosynthesis on underwater survival are impressive. A combination of recently published data allowed quantification of the magnitude of the acclimation response in this species. Gas diffusion resistance in terrestrial leaves underwater was about 15,000 times higher than in air. Strikingly, acclimation to submergence reduced this factor to 400, indicating that acclimated leaves of R. palustris had an approximately 40 times lower gas diffusion resistance than non-acclimated ones.
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Affiliation(s)
- Liesje Mommer
- Experimental Plant Ecology, Institute for Water and Wetland Research, Faculty of Science, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
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32
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Mackenzie TDB, Johnson JM, Campbell DA. Dynamics of fluxes through photosynthetic complexes in response to changing light and inorganic carbon acclimation in Synechococcus elongatus. PHOTOSYNTHESIS RESEARCH 2005; 85:341-57. [PMID: 16170636 DOI: 10.1007/s11120-005-7383-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Accepted: 05/12/2005] [Indexed: 05/04/2023]
Abstract
Cyanobacteria acclimate to environmental inorganic carbon (C(i)) concentrations through re-organisations of photosynthetic function and the induction of carbon concentrating mechanisms (CCMs), which alter and constrain their subsequent acclimation to changing light. We grew cells acclimated to high C(i) (4 mM) or low C(i) (0.02 mM), shifted them from 50 micromol m(-2) s(-1) to 500 micromol m(-2) s(-1), and quantified their photosynthetic performance in parallel with quantitation of allocations to key indicator macromolecules. Pigments cell(-1) declined, PsbA (PS II), AtpB (ATP Synthase), RbcL (Rubisco) and GlnA (Glutamine Synthetase) increased, and PsaC (PS I) remained stable through the light shift. The increase in these protein pools was slower and smaller in low C(i) cells, but acted in both cell types to re-normalise the electron fluxes through the catalytic complexes back toward values before the light shift (for PsbA and GlnA) or even below the initial flux per complex (for RbcL). In contrast, an increased electron flux per PsaC was sustained for at least 6 h after the increase in light. Initially, high levels of PS II cell(-1) and PS II connectivity in high C(i) cells caused a more rapid net photoinactivation of PS II in high C(i) cells than in low C(i) cells, depressing the rate of PS II-specific electron transport (PS II ETR) to levels similar to linear ETR (net O(2) evolution minus respiration). In low C(i) cells, PS II ETR remained in excess of linear ETR and may have helped maintain CCM activity. The pool sizes of PsbA, AtpB and GlnA correlated with cellular growth rate, and changed at similar rates in high C(i) and low C(i) cells when expressed on a generational rather than chronological timescale, which has implications for differing ecology of high and low C(i) cells under variable natural light.
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Affiliation(s)
- Tyler D B Mackenzie
- Department of Biology, University of New Brunswick, Fredericton, NB, E3B 6E1, Canada
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33
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Mommer L, Pons TL, Wolters-Arts M, Venema JH, Visser EJW. Submergence-induced morphological, anatomical, and biochemical responses in a terrestrial species affect gas diffusion resistance and photosynthetic performance. PLANT PHYSIOLOGY 2005; 139:497-508. [PMID: 16126859 PMCID: PMC1203398 DOI: 10.1104/pp.105.064725] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 05/20/2005] [Accepted: 07/11/2005] [Indexed: 05/04/2023]
Abstract
Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and carbohydrates would be continued photosynthesis under water, but this possibility has received only little attention. Here, we combine several techniques to investigate the consequences of anatomical and biochemical responses of the terrestrial species Rumex palustris to submergence for different aspects of photosynthesis under water. The orientation of the chloroplasts in submergence-acclimated leaves was toward the epidermis instead of the intercellular spaces, indicating that underwater CO(2) diffuses through the cuticle and epidermis. Interestingly, both the cuticle thickness and the epidermal cell wall thickness were significantly reduced upon submergence, suggesting a considerable decrease in diffusion resistance. This decrease in diffusion resistance greatly facilitated underwater photosynthesis, as indicated by higher underwater photosynthesis rates in submergence-acclimated leaves at all CO(2) concentrations investigated. The increased availability of internal CO(2) in these "aquatic" leaves reduced photorespiration, and furthermore reduced excitation pressure of the electron transport system and, thus, the risk of photodamage. Acclimation to submergence also altered photosynthesis biochemistry as reduced Rubisco contents were observed in aquatic leaves, indicating a lower carboxylation capacity. Electron transport capacity was also reduced in these leaves but not as strongly as the reduction in Rubisco, indicating a substantial increase of the ratio between electron transport and carboxylation capacity upon submergence. This novel finding suggests that this ratio may be less conservative than previously thought.
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Affiliation(s)
- Liesje Mommer
- Department of Experimental Plant Ecology , Radboud University Nijmegen, The Netherlands.
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MacKenzie TDB, Johnson JM, Cockshutt AM, Burns RA, Campbell DA. Large reallocations of carbon, nitrogen, and photosynthetic reductant among phycobilisomes, photosystems, and Rubisco during light acclimation in Synechococcus elongatus strain PCC7942 are constrained in cells under low environmental inorganic carbon. Arch Microbiol 2005; 183:190-202. [PMID: 15726330 DOI: 10.1007/s00203-005-0761-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 12/12/2004] [Accepted: 01/25/2005] [Indexed: 11/30/2022]
Abstract
Synechococcus elongatus strain PCC7942 cells were grown in high or low environmental concentrations of inorganic C (high-C(i), low-C(i)) and subjected to a light shift from 50 micromol m(-2) s(-1) to 500 micromol m(-2) s(-1). We quantified photosynthetic reductant (O(2) evolution) and molar cellular contents of phycobilisomes, PSII, PSI, and ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) through the light shift. Upon the increase in light, small initial relative decreases in phycobilisomes per cell resulted from near cessation of phycobilisome synthesis and their dilution into daughter cells. Thus, allocation of reductant to phycobilisome synthesis dropped fivefold from pre- to post-light shift. The decrease in phycobilisome synthesis liberated enough material and reductant to allow a doubling of Rubisco and up to a sixfold increase in PSII complexes per cell. Low-C(i) cells had smaller initial phycobilisome pools and upon increased light; their reallocation of reductant from phycobilisome synthesis may have limited the rate and extent of light acclimation, compared to high-C(i) cells. Acclimation to increased light involved large reallocations of C, N, and reductant among different components of the photosynthetic apparatus, but total allocation to the apparatus was fairly stable at ca. 50% of cellular N, and drew 25-50% of reductant from photosynthesis.
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Affiliation(s)
- Tyler D B MacKenzie
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick E3B 6E1, Canada
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