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Wang T, Li D, Tian X, Huang G, He M, Wang C, Kumbhar AN, Woldemicael AG. Mitigating salinity stress through interactions between microalgae and different forms (free-living & alginate gel-encapsulated) of bacteria isolated from estuarine environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171909. [PMID: 38522526 DOI: 10.1016/j.scitotenv.2024.171909] [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: 01/12/2024] [Revised: 03/05/2024] [Accepted: 03/21/2024] [Indexed: 03/26/2024]
Abstract
Salinity stress in estuarine environments poses a significant challenge for microalgal survival and proliferation. The interaction between microalgae and bacteria shows promise in alleviating the detrimental impacts of salinity stress on microalgae. Our study investigates this interaction by co-cultivating Chlorella sorokiniana, a freshwater microalga, with a marine growth-promoting bacterium Pseudomonas gessardii, both of which were isolated from estuary. In this study, bacteria were encapsulated using sodium alginate microspheres to establish an isolated co-culture system, preventing direct exposure between microalgae and bacteria. We evaluated microalgal responses to different salinities (5 PSU, 15 PSU) and interaction modes (free-living, gel-encapsulated), focusing on growth, photosynthesis, cellular metabolism, and extracellular polymeric substances (EPS) properties. High salinity inhibited microalgal proliferation, while gel-fixed interaction boosted Chlorella growth rate by 50.7 %. Both attached and free-living bacteria restored Chlorella's NPQ to normal levels under salt stress. Microalgae in the free-living interaction group exhibited a significantly lower respiratory rate compared to the pure algae group (-17.2 %). Increased salinity led to enhanced EPS polysaccharide secretion by microalgae, particularly in interaction groups (19.7 %). Both salt stress and interaction increased the proportion of aromatic proteins in microalgae's EPS, enhancing its stability by modulating EPS glycosidic bond C-O-C and protein vibrations. This alteration caused microalgal cells to aggregate, free-living bacteria co-culture group, and fixed co-culture group increasing by 427.5 %, 567.1 %, and 704.1 %, respectively. In gel-fixed bacteria groups, reduced neutral lipids don't accumulate starch instead, carbon redirects to cellular growth, aiding salt stress mitigation. These synergistic activities between salinity and bacterial interactions are vital in mitigating salinity stress, improving the resilience and growth of microalgae in saline conditions. Our research sheds light on the mechanisms of microalgal-bacterial interactions in coping with salt stress, offering insights into the response of estuarine microorganisms to global environmental changes and their ecological stability.
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Affiliation(s)
- Tong Wang
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Dan Li
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China; School of Civil Engineering, Yantai University, Yantai 264000, China
| | - Xin Tian
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Guolin Huang
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Meilin He
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China.
| | - Changhai Wang
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China; Co-Innovation Center for Jiangsu Marine Bio-Industry Technology, Lianyungang 222005, China.
| | - Ali Nawaz Kumbhar
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Abeselom Ghirmai Woldemicael
- Jiangsu Key Laboratory of Marine Biology, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
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Belyaeva NE, Bulychev AA, Klementiev KE, Paschenko VZ, Riznichenko GY, Rubin AB. Comparative modeling of fluorescence and P700 induction kinetics for alga Scenedesmus sp. obliques and cyanobacterium Synechocystis sp. PCC 6803. Role of state 2-state 1 transitions and redox state of plastoquinone pool. Cell Biochem Biophys 2024:10.1007/s12013-024-01224-w. [PMID: 38340281 DOI: 10.1007/s12013-024-01224-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 01/24/2024] [Indexed: 02/12/2024]
Abstract
The model of thylakoid membrane system (T-M model) (Belyaeva et al. Photosynth Res 2019, 140:1-19) has been improved in order to analyze the induction data for dark-adapted samples of algal (Scenedesmus obliques) and cyanobacterial (Synechocystis sp. PCC 6803) cells. The fluorescence induction (FI) curves of Scenedesmus were measured at light exposures of 5 min, while FI and P700 redox transformations of Synechocystis were recorded in parallel for 100 s intervals. Kinetic data comprising the OJIP-SMT fluorescence induction and OABCDEF P700+ absorbance changes were used to study the processes underlying state transitions qT2→1 and qT1→2 associated with the increase/decrease in Chl fluorescence emission. A formula with the Hill kinetics (Ebenhöh et al. Philos Trans R Soc B 2014, 369:20130223) was introduced into the T-M model, with a new variable to imitate the flexible size of antenna AntM(t) associated with PSII. Simulations revealed that the light-harvesting capacity of PSII increases with a corresponding decrease for that of PSI upon the qT2→1 transition induced by plastoquinone (PQ) pool oxidation. The complete T-M model fittings were attained on Scenedesmus or Synechocystis fast waves OJIPS of FI, while SMT wave of FI was reproduced at intervals shorter than 5 min. Also the fast P700 redox transitions (OABC) for Synechocystis were fitted exactly. Reasonable sets of algal and cyanobacterial electron/proton transfer (ET/PT) parameters were found. In the case of Scenedesmus, ET/PT traits remained the same irrespective of modeling with or without qT2→1 transitions. Simulations indicated a high extent (20%) of the PQ pool reduction under dark conditions in Synechocystis compared to 2% in Scenedesmus.
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Affiliation(s)
- N E Belyaeva
- Biological Faculty, Moscow State University, Moscow, 119234, Russia.
| | - A A Bulychev
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - K E Klementiev
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
- Biological Faculty, Shenzhen MSU-BIT University, Shenzhen, 518172, China
| | - V Z Paschenko
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - G Yu Riznichenko
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - A B Rubin
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
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Schomaker RA, Richardson TL, Dudycha JL. Consequences of light spectra for pigment composition and gene expression in the cryptophyte Rhodomonas salina. Environ Microbiol 2023; 25:3280-3297. [PMID: 37845005 DOI: 10.1111/1462-2920.16523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 09/28/2023] [Indexed: 10/18/2023]
Abstract
Algae with a more diverse suite of pigments can, in principle, exploit a broader swath of the light spectrum through chromatic acclimation, the ability to maximize light capture via plasticity of pigment composition. We grew Rhodomonas salina in wide-spectrum, red, green, and blue environments and measured how pigment composition differed. We also measured expression of key light-capture and photosynthesis-related genes and performed a transcriptome-wide expression analysis. We observed the highest concentration of phycoerythrin in green light, consistent with chromatic acclimation. Other pigments showed trends inconsistent with chromatic acclimation, possibly due to feedback loops among pigments or high-energy light acclimation. Expression of some photosynthesis-related genes was sensitive to spectrum, although expression of most was not. The phycoerythrin α-subunit was expressed two-orders of magnitude greater than the β-subunit even though the peptides are needed in an equimolar ratio. Expression of genes related to chlorophyll-binding and phycoerythrin concentration were correlated, indicating a potential synthesis relationship. Pigment concentrations and expression of related genes were generally uncorrelated, implying post-transcriptional regulation of pigments. Overall, most differentially expressed genes were not related to photosynthesis; thus, examining associations between light spectrum and other organismal functions, including sexual reproduction and glycolysis, may be important.
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Affiliation(s)
| | - Tammi L Richardson
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
- School of the Earth, Ocean, & Environment, University of South Carolina, Columbia, South Carolina, USA
| | - Jeffry L Dudycha
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
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Stark GF, Martin RM, Smith LE, Wei B, Hellweger FL, Bullerjahn GS, McKay RML, Boyer GL, Wilhelm SW. Microcystin aids in cold temperature acclimation: Differences between a toxic Microcystis wildtype and non-toxic mutant. HARMFUL ALGAE 2023; 129:102531. [PMID: 37951605 PMCID: PMC10640677 DOI: 10.1016/j.hal.2023.102531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 11/14/2023]
Abstract
For Microcystis aeruginosa PCC 7806, temperature decreases from 26 °C to 19 °C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, reactive oxygen species damage, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19 °C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents.
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Affiliation(s)
- Gwendolyn F Stark
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Laura E Smith
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Bofan Wei
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, The University of Windsor, Windsor, ON, Canada
| | - Gregory L Boyer
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA.
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5
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Stark GF, Martin RM, Smith LE, Wei B, Hellweger FL, Bullerjahn GS, McKay RML, Boyer GL, Wilhelm SW. Cool temperature acclimation in toxigenic Microcystis aeruginosa PCC 7806 and its non-toxigenic mutant. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555099. [PMID: 37693631 PMCID: PMC10491114 DOI: 10.1101/2023.08.28.555099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
For Microcystis aeruginosa PCC 7806, temperature decreases from 26° C to 19° C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19° C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents.
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Affiliation(s)
- Gwendolyn F Stark
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Laura E Smith
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Bofan Wei
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, The University of Windsor, Windsor, ON, Canada
| | - Gregory L Boyer
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
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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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Kholssi R, Lougraimzi H, Moreno-Garrido I. Influence of salinity and temperature on the growth, productivity, photosynthetic activity and intracellular ROS of two marine microalgae and cyanobacteria. MARINE ENVIRONMENTAL RESEARCH 2023; 186:105932. [PMID: 36863077 DOI: 10.1016/j.marenvres.2023.105932] [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: 11/16/2022] [Revised: 02/13/2023] [Accepted: 02/23/2023] [Indexed: 06/01/2023]
Abstract
Global Climate Change could change physical parameters in oceans, such as salinity and temperature. The impact of such changes in phytoplankton has not been well stated yet. In this study the effect of combination of three levels of temperature (20, 23, and 26 °C), and three levels of salinity (33, 36, and 39) on growth of a mixture co-cultivation of three common species from phytoplankton (one cyanobacteria, Synechococcus sp., and two microalgae, Chaetoceros gracilis, and Rhodomonas baltica), is monitored by flow cytometry under controlled cultivation conditions in a 96 h study. Chlorophyll content, enzymes activities and oxidative stress were also measured. Results demonstrate that cultures of Synechococcus sp. Exhibited a high growth at the highest temperature chosen in this study (26 °C) combined with the three selected salinity levels 33, 36, and 39. Nevertheless, Chaetoceros gracilis grew very slowly with the combination of high temperature (39 °C) and all salinities, while Rhodomonas baltica did not grow at temperatures higher than 23 °C. Maximum dry biomass and ash-free dry weight for the microalgal mixture were reached at salinity of 39 and temperature of 20 °C, the but highest chlorophyll fluorescence values were found at 30 salinity and 20 °C, decreasing as salinity and temperature increased.
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Affiliation(s)
- Rajaa Kholssi
- Composting Research Group, Faculty of Sciences, University of Burgos, Burgos, Spain; Institute of Marine Sciences of Andalusia (ICMAN-CSIC), Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain.
| | - Hanane Lougraimzi
- Laboratory of Plant, Animal and Agro-Industry Productions, Faculty of Sciences, Ibn Tofail University, BP: 242, 14000, Kenitra, Morocco
| | - Ignacio Moreno-Garrido
- Institute of Marine Sciences of Andalusia (ICMAN-CSIC), Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain
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Ogawa T, Sonoike K. Screening of mutants using chlorophyll fluorescence. JOURNAL OF PLANT RESEARCH 2021; 134:653-664. [PMID: 33686578 DOI: 10.1007/s10265-021-01276-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Chlorophyll fluorescence has been widely used for the estimation of photosynthesis or its regulatory mechanisms. Chlorophyll fluorescence measurements are the methods with non-destructive nature and do not require contact between plant materials and fluorometers. Furthermore, the measuring process is very rapid. These characteristics of chlorophyll fluorescence measurements make them a suitable tool to screen mutants of photosynthesis-related genes. Furthermore, it has been shown that genes with a wide range of functions can be also analyzed by chlorophyll fluorescence through metabolic interactions. In this short review, we would like to first introduce the basic principle of the chlorophyll fluorescence measurements, and then explore the advantages and limitation of various screening methods. The emphasis is on the possibility of chlorophyll fluorescence measurements to screen mutants defective in metabolisms other than photosynthesis.
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Affiliation(s)
- Takako Ogawa
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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Zavřel T, Schoffman H, Lukeš M, Fedorko J, Keren N, Červený J. Monitoring fitness and productivity in cyanobacteria batch cultures. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Photosynthetic monitoring techniques indicate maximum glycogen accumulation in nitrogen-limited Synechocystis sp. PCC 6803 culture. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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The Role of Selected Wavelengths of Light in the Activity of Photosystem II in Gloeobacter violaceus. Int J Mol Sci 2021; 22:ijms22084021. [PMID: 33924720 PMCID: PMC8069770 DOI: 10.3390/ijms22084021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 01/03/2023] Open
Abstract
Gloeobacter violaceus is a cyanobacteria species with a lack of thylakoids, while photosynthetic antennas, i.e., phycobilisomes (PBSs), photosystem II (PSII), and I (PSI), are located in the cytoplasmic membrane. We verified the hypothesis that blue–red (BR) light supplemented with a far-red (FR), ultraviolet A (UVA), and green (G) light can affect the photosynthetic electron transport chain in PSII and explain the differences in the growth of the G. violaceus culture. The cyanobacteria were cultured under different light conditions. The largest increase in G. violaceus biomass was observed only under BR + FR and BR + G light. Moreover, the shape of the G. violaceus cells was modified by the spectrum with the addition of G light. Furthermore, it was found that both the spectral composition of light and age of the cyanobacterial culture affect the different content of phycobiliproteins in the photosynthetic antennas (PBS). Most likely, in cells grown under light conditions with the addition of FR and G light, the average antenna size increased due to the inactivation of some reaction centers in PSII. Moreover, the role of PSI and gloeorhodopsin as supplementary sources of metabolic energy in the G. violaceus growth is discussed.
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Wessendorf RL, Lu Y. Introducing an Arabidopsis thaliana Thylakoid Thiol/Disulfide-Modulating Protein Into Synechocystis Increases the Efficiency of Photosystem II Photochemistry. FRONTIERS IN PLANT SCIENCE 2019; 10:1284. [PMID: 31681379 PMCID: PMC6805722 DOI: 10.3389/fpls.2019.01284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Photosynthetic species are subjected to a variety of environmental stresses, including suboptimal irradiance. In oxygenic photosynthetic organisms, a major effect of high light exposure is damage to the Photosystem II (PSII) reaction-center protein D1. This process even happens under low or moderate light. To cope with photodamage to D1, photosynthetic organisms evolved an intricate PSII repair and reassembly cycle, which requires the participation of different auxiliary proteins, including thiol/disulfide-modulating proteins. Most of these auxiliary proteins exist ubiquitously in oxygenic photosynthetic organisms. Due to differences in mobility and environmental conditions, land plants are subject to more extensive high light stress than algae and cyanobacteria. Therefore, land plants evolved additional thiol/disulfide-modulating proteins, such as Low Quantum Yield of PSII 1 (LQY1), to aid in the repair and reassembly cycle of PSII. In this study, we introduced an Arabidopsis thaliana homolog of LQY1 (AtLQY1) into the cyanobacterium Synechocystis sp. PCC6803 and performed a series of biochemical and physiological assays on AtLQY1-expressing Synechocystis. At a moderate growth light intensity (50 µmol photons m-2 s-1), AtLQY1-expressing Synechocystis was found to have significantly higher F v /F m , and lower nonphotochemical quenching and reactive oxygen species levels than the empty-vector control, which is opposite from the loss-of-function Atlqy1 mutant phenotype. Light response curve analysis of PSII operating efficiency and electron transport rate showed that AtLQY1-expressing Synechocystis also outperform the empty-vector control under higher light intensities. The increases in F v /F m , PSII operating efficiency, and PSII electron transport rate in AtLQY1-expressing Synechocystis under such growth conditions most likely come from an increased amount of PSII, because the level of D1 protein was found to be higher in AtLQY1-expressing Synechocystis. These results suggest that introducing AtLQY1 is beneficial to Synechocystis.
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Affiliation(s)
| | - Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
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13
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Blanco-Ameijeiras S, Moisset SAM, Trimborn S, Campbell DA, Heiden JP, Hassler CS. Elemental Stoichiometry and Photophysiology Regulation of Synechococcus sp. PCC7002 Under Increasing Severity of Chronic Iron Limitation. PLANT & CELL PHYSIOLOGY 2018; 59:1803-1816. [PMID: 29860486 DOI: 10.1093/pcp/pcy097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/11/2018] [Indexed: 06/08/2023]
Abstract
Iron (Fe) is an essential cofactor for many metabolic enzymes of photoautotrophs. Although Fe limits phytoplankton productivity in broad areas of the ocean, phytoplankton have adapted their metabolism and growth to survive in these conditions. Using the euryhaline cyanobacterium Synechococcus sp. PCC7002, we investigated the physiological responses to long-term acclimation to four levels of Fe availability representative of the contemporary ocean (36.7, 3.83, 0.47 and 0.047 pM Fe'). With increasing severity of Fe limitation, Synechococcus sp. cells gradually decreased their volume and growth while increasing their energy allocation into organic carbon and nitrogen cellular pools. Furthermore, the total cellular content of pigments decreased. Additionally, with increasing severity of Fe limitation, intertwined responses of PSII functional cross-section (σPSII), re-oxidation time of the plastoquinone primary acceptor QA (τ) and non-photochemical quenching revealed a shift in the photophysiological response between mild to strong Fe limitation compared with severe limitation. Under mild and strong Fe limitation, there was a decrease in linear electron transport accompanied by progressive loss of state transitions. Under severe Fe limitation, state transitions seemed to be largely supplanted by alternative electron pathways. In addition, mechanisms to dissipate energy excess and minimize oxidative stress associated with high irradiances increased with increasing severity of Fe limitation. Overall, our results establish the sequence of physiological strategies adopted by the cells under increasing severity of chronic Fe limitation, within a range of Fe concentrations relevant to modern ocean biogeochemistry.
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Affiliation(s)
- Sonia Blanco-Ameijeiras
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Boulevard Carl-Vogt 66, Geneva 4, Switzerland
| | - Sophie A M Moisset
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Boulevard Carl-Vogt 66, Geneva 4, Switzerland
| | - Scarlett Trimborn
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, Germany
- Marine Botany, University of Bremen, Leobener Strasse NW2-A, Bremen, Germany
| | - Douglas A Campbell
- Biology, Faculty of Science, Mount Allison University, Sackville, NB, Canada
| | - Jasmin P Heiden
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, Germany
- Marine Botany, University of Bremen, Leobener Strasse NW2-A, Bremen, Germany
| | - Christel S Hassler
- Department F.-A. Forel for Environmental and Aquatic Sciences, Faculty of Science, University of Geneva, Boulevard Carl-Vogt 66, Geneva 4, Switzerland
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Karthikaichamy A, Deore P, Srivastava S, Coppel R, Bulach D, Beardall J, Noronha S. Temporal acclimation of Microchloropsis gaditana CCMP526 in response to hypersalinity. BIORESOURCE TECHNOLOGY 2018; 254:23-30. [PMID: 29413927 DOI: 10.1016/j.biortech.2018.01.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 06/08/2023]
Abstract
Evaporation from culture ponds and raceways can subject algae to hypersalinity stress, and this is exacerbated by global warming. We investigated the effect of salinity on a marine microalga, Microchloropsis gaditana, which is of industrial significance because of its high lipid-accumulating capability. Both short-term (hours) and medium-term (days) effects of salinity were studied across various salinities (37.5, 55, 70 and 100 PSU). Salinity above 55 PSU suppressed cell growth and specific growth rate was significantly reduced at 100 PSU. Photosynthesis (Fv/Fm, rETRmax and Ik) was severely affected at high salinity conditions. Total carbohydrate per cell increased ∼1.7-fold after 24 h, which is consistent with previous findings that salinity induces osmolyte production to counter osmotic shock. In addition, accumulation of lipid increased by ∼4.6-fold in response to salinity. Our findings indicate a possible mechanism of acclimation to salinity, opening up new frontiers for osmolytes in pharmacological and cosmetics applications.
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Affiliation(s)
| | - Pranali Deore
- IITB-Monash Research Academy, IIT Bombay, Mumbai 400076, India
| | - Sanjeeva Srivastava
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai 400076, India
| | - Ross Coppel
- Department of Microbiology, Monash University, Clayton 3800, Victoria, Australia
| | - Dieter Bulach
- Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne 3010, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton 3800, Victoria, Australia
| | - Santosh Noronha
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
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15
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Ogawa T, Sonoike K. Evaluation of the Condition of Respiration and Photosynthesis by Measuring Chlorophyll Fluorescence in Cyanobacteria. Bio Protoc 2018; 8:e2834. [DOI: 10.21769/bioprotoc.2834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 11/02/2022] Open
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16
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Silva Benavides AM, Ranglová K, Malapascua JR, Masojídek J, Torzillo G. Diurnal changes of photosynthesis and growth of Arthrospira platensis cultured in a thin-layer cascade and an open pond. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.10.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Perkins RG, Bagshaw E, Mol L, Williamson CJ, Fagan D, Gamble M, Yallop ML. Photoacclimation by Arctic cryoconite phototrophs. FEMS Microbiol Ecol 2017; 93:3003318. [PMID: 28334248 DOI: 10.1093/femsec/fix018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 02/16/2017] [Indexed: 11/14/2022] Open
Abstract
Cryoconite is a matrix of sediment, biogenic polymer and a microbial community that resides on glacier surfaces. The phototrophic component of this community is well adapted to this extreme environment, including high light stress. Photoacclimation of the cryoconite phototrophic community on Longyearbreen, Svalbard, was investigated using in situ variable chlorophyll fluorescence. Rapid light curves (RLCs) and induction-recovery curves were used to analyse photosystem II quantum efficiency, relative electron transport rate and forms of downregulation including non-photochemical quenching (NPQ) and state transitions in cyanobacteria. Phototrophs used a combination of behavioural and physiological photochemical downregulation. Behavioural downregulation is hypothesised to incorporate chloroplast movement and cell or filament positioning within the sediment matrix in order to shade from high light, which resulted in a lack of saturation of RLCs and hence overestimation of productivity. Physiological downregulation likely consisted of biphasic NPQ, comprising a steadily induced light-dependent form and a light-independent NPQ that was not reversed with decreasing light intensity. State transitions by cyanobacteria were the most likely physiological downregulation employed by cyanobacteria within the mixed phototroph community. These findings demonstrate that cryoconite phototrophs combine multiple forms of physiological and behavioural downregulation to optimise light exposure and maximise photosynthetic productivity. This plasticity of photoacclimation enables them to survive productively in the high-light stress environment on the ice surface.
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Affiliation(s)
- Rupert G Perkins
- Cold Climate Research, School of Earth and Ocean Sciences, Cardiff University, Park Place, Cardiff CF10 3AT, UK
| | - Elizabeth Bagshaw
- Cold Climate Research, School of Earth and Ocean Sciences, Cardiff University, Park Place, Cardiff CF10 3AT, UK
| | - Lisa Mol
- Department of Geography and Environmental Management, UWE Bristol, Coldharbour Lane, Bristol BS16 1QY, UK
| | - Christopher J Williamson
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Dan Fagan
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Maggie Gamble
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Marian L Yallop
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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18
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Ogawa T, Misumi M, Sonoike K. Estimation of photosynthesis in cyanobacteria by pulse-amplitude modulation chlorophyll fluorescence: problems and solutions. PHOTOSYNTHESIS RESEARCH 2017; 133:63-73. [PMID: 28283890 DOI: 10.1007/s11120-017-0367-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/02/2017] [Indexed: 05/09/2023]
Abstract
Cyanobacteria are photosynthetic prokaryotes and widely used for photosynthetic research as model organisms. Partly due to their prokaryotic nature, however, estimation of photosynthesis by chlorophyll fluorescence measurements is sometimes problematic in cyanobacteria. For example, plastoquinone pool is reduced in the dark-acclimated samples in many cyanobacterial species so that conventional protocol developed for land plants cannot be directly applied for cyanobacteria. Even for the estimation of the simplest chlorophyll fluorescence parameter, F v/F m, some additional protocol such as addition of DCMU or illumination of weak blue light is necessary. In this review, those problems in the measurements of chlorophyll fluorescence in cyanobacteria are introduced, and solutions to those problems are given.
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Affiliation(s)
- Takako Ogawa
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, 162-8480, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Masahiro Misumi
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, 162-8480, Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, 162-8480, Japan.
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19
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Islam MA, Beardall J. Growth and Photosynthetic Characteristics of Toxic and Non-Toxic Strains of the Cyanobacteria Microcystis aeruginosa and Anabaena circinalis in Relation to Light. Microorganisms 2017; 5:E45. [PMID: 28777340 PMCID: PMC5620636 DOI: 10.3390/microorganisms5030045] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 07/26/2017] [Accepted: 08/02/2017] [Indexed: 11/16/2022] Open
Abstract
Cyanobacteria are major bloom-forming organisms in freshwater ecosystems and many strains are known to produce toxins. Toxin production requires an investment in energy and resources. As light is one of the most important factors for cyanobacterial growth, any changes in light climate might affect cyanobacterial toxin production as well as their growth and physiology. To evaluate the effects of light on the growth and physiological parameters of both toxic and non-toxic strains of Microcystis aeruginosa and Anabaena circinalis, cultures were grown at a range of light intensities (10, 25, 50, 100, 150 and 200 µmol m-2 s-1). The study revealed that the toxic strains of both species (CS558 for M. aeruginosa and CS537 and CS541 for A. circinalis) showed growth (µ) saturation at a higher light intensity compared to the non-toxic strains (CS338 for M. aeruginosa and CS534 for A. circinalis). Both species showed differences in chlorophyll a, carotenoid, allophycocyanin (APC) and phycoerythrin (PE) content between strains. There were also differences in dark respiration (Rd), light saturated oxygen evolution rates (Pmax) and efficiency of light harvesting (α) between strains. All other physiological parameters showed no statistically significant differences between strains. This study suggest that the different strains respond differently to different light habitats. Thus, changes in light availability may affect bloom intensity of toxic and nontoxic strains of cyanobacteria by changing the dominance and succession patterns.
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Affiliation(s)
- M Ashraful Islam
- School of Biological Sciences, Monash University, Clayton VIC 3800, Australia.
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton VIC 3800, Australia.
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20
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Photosystem II-cyclic electron flow powers exceptional photoprotection and record growth in the microalga Chlorella ohadii. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:873-883. [PMID: 28734933 DOI: 10.1016/j.bbabio.2017.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/12/2017] [Accepted: 07/14/2017] [Indexed: 01/13/2023]
Abstract
The desert microalga Chlorella ohadii was reported to grow at extreme light intensities with minimal photoinhibition, tolerate frequent de/re-hydrations, yet minimally employs antenna-based non-photochemical quenching for photoprotection. Here we investigate the molecular mechanisms by measuring Photosystem II charge separation yield (chlorophyll variable fluorescence, Fv/Fm) and flash-induced O2 yield to measure the contributions from both linear (PSII-LEF) and cyclic (PSII-CEF) electron flow within PSII. Cells grow increasingly faster at higher light intensities (μE/m2/s) from low (20) to high (200) to extreme (2000) by escalating photoprotection via shifting from PSII-LEF to PSII-CEF. This shifts PSII charge separation from plastoquinone reduction (PSII-LEF) to plastoquinol oxidation (PSII-CEF), here postulated to enable proton gradient and ATP generation that powers photoprotection. Low light-grown cells have unusually small antennae (332 Chl/PSII), use mainly PSII-LEF (95%) and convert 40% of PSII charge separations into O2 (a high O2 quantum yield of 0.06mol/mol PSII/flash). High light-grown cells have smaller antenna and lower PSII-LEF (63%). Extreme light-grown cells have only 42 Chl/PSII (no LHCII antenna), minimal PSII-LEF (10%), and grow faster than any known phototroph (doubling time 1.3h). Adding a synthetic quinone in excess to supplement the PQ pool fully uncouples PSII-CEF from its natural regulation and produces maximum PSII-LEF. Upon dark adaptation PSII-LEF rapidly reverts to PSII-CEF, a transient protection mechanism to conserve water and minimize the cost of antenna biosynthesis. The capacity of the electron acceptor pool (plastoquinone pool), and the characteristic times for exchange of (PQH2)B with PQpool and reoxidation of (PQH2)pool were determined.
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21
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Characterization of the influence of chlororespiration on the regulation of photosynthesis in the glaucophyte Cyanophora paradoxa. Sci Rep 2017; 7:46100. [PMID: 28387347 PMCID: PMC5384210 DOI: 10.1038/srep46100] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/10/2017] [Indexed: 01/19/2023] Open
Abstract
Glaucophytes are primary symbiotic algae with unique plastids called cyanelles, whose structure is most similar to ancestral cyanobacteria among plastids in photosynthetic organisms. Here we compare the regulation of photosynthesis in glaucophyte with that in cyanobacteria in the aim of elucidating the changes caused by the symbiosis in the interaction between photosynthetic electron transfer and other metabolic pathways. Chlorophyll fluorescence measurements of the glaucophyte Cyanophora paradoxa NIES-547 indicated that plastoquinone (PQ) pool in photosynthetic electron transfer was reduced in the dark by chlororespiration. The levels of nonphotochemical quenching of chlorophyll fluorescence was high in the dark but decreased under low light, and increased again under high light. This type of concave light dependence was quite similar to that observed in cyanobacteria. Moreover, the addition of ionophore hardly affected nonphotochemical quenching, suggesting state transition as a main component of the regulatory system in C. paradoxa. These results suggest that cyanelles of C. paradoxa retain many of the characteristics observed in their ancestral cyanobacteria. From the viewpoint of metabolic interactions, C. paradoxa is the primary symbiotic algae most similar to cyanobacteria than other lineages of photosynthetic organisms.
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Misumi M, Katoh H, Tomo T, Sonoike K. Relationship Between Photochemical Quenching and Non-Photochemical Quenching in Six Species of Cyanobacteria Reveals Species Difference in Redox State and Species Commonality in Energy Dissipation. PLANT & CELL PHYSIOLOGY 2016; 57:1510-1517. [PMID: 26712847 PMCID: PMC4937784 DOI: 10.1093/pcp/pcv185] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 10/12/2015] [Indexed: 05/20/2023]
Abstract
Although the photosynthetic reaction center is well conserved among different cyanobacterial species, the modes of metabolism, e.g. respiratory, nitrogen and carbon metabolism and their mutual interaction, are quite diverse. To explore such uniformity and diversity among cyanobacteria, here we compare the influence of the light environment on the condition of photosynthetic electron transport through Chl fluorescence measurement of six cyanobacterial species grown under the same photon flux densities and at the same temperature. In the dark or under weak light, up to growth light, a large difference in the plastoquinone (PQ) redox condition was observed among different cyanobacterial species. The observed difference indicates that the degree of interaction between respiratory electron transfer and photosynthetic electron transfer differs among different cyanobacterial species. The variation could not be ascribed to the phylogenetic differences but possibly to the light environment of the original habitat. On the other hand, changes in the redox condition of PQ were essentially identical among different species at photon flux densities higher than the growth light. We further analyzed the response to high light by using a typical energy allocation model and found that 'non-regulated' thermal dissipation was increased under high-light conditions in all cyanobacterial species tested. We assume that such 'non-regulated' thermal dissipation may be an important 'regulatory' mechanism in the acclimation of cyanobacterial cells to high-light conditions.
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Affiliation(s)
- Masahiro Misumi
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan
| | - Hiroshi Katoh
- Division of Plant Functional Genomics, Life Science Research Center, Mie University, Kurimamachiya 1577, Tsu, Mie, 514-8507 Japan
| | - Tatsuya Tomo
- Department of Biology, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-Ku, Tokyo, 162-8601 Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan
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23
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Markou G, Depraetere O, Muylaert K. Effect of ammonia on the photosynthetic activity of Arthrospira and Chlorella: A study on chlorophyll fluorescence and electron transport. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.03.039] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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Ogawa T, Sonoike K. Effects of Bleaching by Nitrogen Deficiency on the Quantum Yield of Photosystem II in Synechocystis sp. PCC 6803 Revealed by Chl Fluorescence Measurements. PLANT & CELL PHYSIOLOGY 2016; 57:558-567. [PMID: 26858287 DOI: 10.1093/pcp/pcw010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
Estimation of photosynthesis by Chl fluorescence measurement of cyanobacteria is always problematic due to the interference from respiratory electron transfer and from phycocyanin fluorescence. The interference from respiratory electron transfer could be avoided by the use of DCMU or background illumination by blue light, which oxidizes the plastoquinone pool that tends to be reduced by respiration. On the other hand, the precise estimation of photosynthesis in cells with a different phycobilisome content by Chl fluorescence measurement is difficult. By subtracting the basal fluorescence due to the phycobilisome and PSI, it becomes possible to estimate the precise maximum quantum yield of PSII in cyanobacteria. Estimated basal fluorescence accounted for 60% of the minimum fluorescence, resulting in a large difference between the 'apparent' yield and 'true' yield under high phycocyanin conditions. The calculated value of the 'true' maximum quantum yield of PSII was around 0.8, which was similar to the value observed in land plants. The results suggest that the cause of the apparent low yield reported in cyanobacteria is mainly ascribed to the interference from phycocyanin fluorescence. We also found that the 'true' maximum quantum yield of PSII decreased under nitrogen-deficient conditions, suggesting the impairment of the PSII reaction center, while the 'apparent' maximum quantum yield showed a marginal change under the same conditions. Due to the high contribution of phycocyanin fluorescence in cyanobacteria, it is essential to eliminate the influence of the change in phycocyanin content on Chl fluorescence measurement and to evaluate the 'true' photosynthetic condition.
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Affiliation(s)
- Takako Ogawa
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan Japan Society for the Promotion of Science, Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan
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25
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Rabouille S, Claquin P. Photosystem-II shutdown evolved with Nitrogen fixation in the unicellular diazotroph Crocosphaera watsonii. Environ Microbiol 2016; 18:477-85. [PMID: 26643607 DOI: 10.1111/1462-2920.13157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/11/2015] [Accepted: 11/27/2015] [Indexed: 11/30/2022]
Abstract
Protection of nitrogenase from oxygen in unicellular Cyanobacteria is obtained by temporal separation of photosynthesis and diazotrophy through transcriptional and translational regulations of nitrogenase. But diazotrophs can face environmental situations in which N2 fixation occurs significantly in the light, and we believe that another control operates to make it possible. The night-time shutdown of PSII activity is a peculiar behaviour that discriminates Crocosphaera watsonii WH8501 from any other phototroph, whether prokaryote or eukaryote. This phenomenon is not only due to the plastoquinone pool redox status, and suggests that the sentinel D1 protein, expressed in periods of nitrogen fixation, is inactive. Results demonstrate a tight constraint of oxygen evolution in C. watsonii as additional protection of nitrogenase activity and suggest a possible recycling of cellular components.
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Affiliation(s)
- Sophie Rabouille
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7093, LOV, Observatoire océanologique, F-06230, Villefranche/mer, France.,CNRS, UMR 7093, LOV, Observatoire océanologique, F-06230, Villefranche/mer, France
| | - Pascal Claquin
- Université de Caen-Normandie, BOREA, Caen, France.,CNRS-7208, IRD-207, MNHN, UPMC, UniCaen, BOREA, Caen, France
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26
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Alam MA, Gauslaa Y, Solhaug KA. Soluble carbohydrates and relative growth rates in chloro-, cyano- and cephalolichens: effects of temperature and nocturnal hydration. THE NEW PHYTOLOGIST 2015; 208:750-62. [PMID: 26017819 DOI: 10.1111/nph.13484] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 05/05/2015] [Indexed: 05/15/2023]
Abstract
This growth chamber experiment evaluates how temperature and humidity regimes shape soluble carbohydrate pools and growth rates in lichens with different photobionts. We assessed soluble carbohydrates, relative growth rates (RGRs) and relative thallus area growth rates (RTA GRs) in Parmelia sulcata (chlorolichen), Peltigera canina (cyanolichen) and Peltigera aphthosa (cephalolichen) cultivated for 14 d (150 μmol m(-2) s(-1) ; 12-h photoperiod) at four day : night temperatures (28 : 23°C, 20 : 15°C, 13 : 8°C, 6 : 1°C) and two hydration regimes (hydration during the day, dry at night; hydration day : night). The major carbohydrates were mannitol (cephalolichen), glucose (cyanolichen) and arabitol (chlorolichen). Mannitol occurred in all species. During cultivation, total carbohydrate pools decreased in cephalo-/cyanolichens, but increased in the chlorolichen. Carbohydrates varied less than growth with temperature and humidity. All lichens grew rapidly, particularly at 13 : 8°C. RGRs and RTA GRs were significantly higher in lichens hydrated for 24 h than for 12 h. Strong photoinhibition occurred in cephalo- and cyanolichens kept in cool dry nights, resulting in positive relationships between RGR and dark-adapted photosystem II (PSII) efficiency (Fv /Fm ). RGR increased significantly with the photobiont-specific carbohydrate pools within all species. Average RGR peaked in the chlorolichen lowest in total and photobiont carbohydrates. Nocturnal hydration improved recovery from photoinhibition and/or enhanced conversion rates of photosynthates into growth.
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Affiliation(s)
- Md Azharul Alam
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, NO-1432, Ås, Norway
| | - Yngvar Gauslaa
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, NO-1432, Ås, Norway
| | - Knut Asbjørn Solhaug
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, NO-1432, Ås, Norway
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27
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Schuurmans RM, van Alphen P, Schuurmans JM, Matthijs HCP, Hellingwerf KJ. Comparison of the Photosynthetic Yield of Cyanobacteria and Green Algae: Different Methods Give Different Answers. PLoS One 2015; 10:e0139061. [PMID: 26394153 PMCID: PMC4578884 DOI: 10.1371/journal.pone.0139061] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/07/2015] [Indexed: 11/18/2022] Open
Abstract
The societal importance of renewable carbon-based commodities and energy carriers has elicited a particular interest for high performance phototrophic microorganisms. Selection of optimal strains is often based on direct comparison under laboratory conditions of maximal growth rate or additional valued features such as lipid content. Instead of reporting growth rate in culture, estimation of photosynthetic efficiency (quantum yield of PSII) by pulse-amplitude modulated (PAM) fluorimetry is an often applied alternative method. Here we compared the quantum yield of PSII and the photonic yield on biomass for the green alga Chlorella sorokiniana 211-8K and the cyanobacterium Synechocystis sp. PCC 6803. Our data demonstrate that the PAM technique inherently underestimates the photosynthetic efficiency of cyanobacteria by rendering a high F0 and a low FM, specifically after the commonly practiced dark pre-incubation before a yield measurement. Yet when comparing the calculated biomass yield on light in continuous culture experiments, we obtained nearly equal values for both species. Using mutants of Synechocystis sp. PCC 6803, we analyzed the factors that compromise its PAM-based quantum yield measurements. We will discuss the role of dark respiratory activity, fluorescence emission from the phycobilisomes, and the Mehler-like reaction. Based on the above observations we recommend that PAM measurements in cyanobacteria are interpreted only qualitatively.
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Affiliation(s)
- R. Milou Schuurmans
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Pascal van Alphen
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - J. Merijn Schuurmans
- Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans C. P. Matthijs
- Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas J. Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Photanol BV, Amsterdam, The Netherlands
- * E-mail:
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28
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Daddy S, Zhan J, Jantaro S, He C, He Q, Wang Q. A novel high light-inducible carotenoid-binding protein complex in the thylakoid membranes of Synechocystis PCC 6803. Sci Rep 2015; 5:9480. [PMID: 25820628 PMCID: PMC4377637 DOI: 10.1038/srep09480] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 02/27/2015] [Indexed: 11/09/2022] Open
Abstract
Synechocystis sp. PCC 6803 is a model cyanobacterium extensively used to study photosynthesis. Here we reveal a novel high light-inducible carotenoid-binding protein complex (HLCC) in the thylakoid membranes of Synechocystis PCC 6803 cells exposed to high intensity light. Zeaxanthin and myxoxanthophyll accounted for 29.8% and 54.8%, respectively, of the carotenoids bound to the complex. Using Blue-Native PAGE followed by 2D SDS-PAGE and mass spectrometry, we showed that the HLCC consisted of Slr1128, IsiA, PsaD, and HliA/B. We confirmed these findings by SEAD fluorescence cross-linking and anti-PsaD immuno-coprecipitation analyses. The expression of genes encoding the protein components of the HLCC was enhanced by high light illumination and artificial oxidative stress. Deletion of these proteins resulted in impaired state transition and increased sensitivity to oxidative and/or high light stress, as indicated by increased membrane peroxidation. Therefore, the HLCC protects thylakoid membranes from extensive photooxidative damage, likely via a mechanism involving state transition.
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Affiliation(s)
- Soumana Daddy
- Department of Biology, University of Arkansas at Little Rock, Little Rock, AR 72204
| | - Jiao Zhan
- 1] Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China [2] University of Chinese Academy of Sciences, Beijing 100039, China
| | - Saowarath Jantaro
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Payathai Road, Patumwan, Bangkok 10330, Thailand
| | - Chenliu He
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Qingfang He
- 1] Department of Biology, University of Arkansas at Little Rock, Little Rock, AR 72204 [2] Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan, Shandong 250100, China
| | - Qiang Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
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Ogawa T, Sonoike K. Dissection of respiration and photosynthesis in the cyanobacterium Synechocystis sp. PCC6803 by the analysis of chlorophyll fluorescence. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 144:61-7. [DOI: 10.1016/j.jphotobiol.2015.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 10/24/2022]
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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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Pierangelini M, Stojkovic S, Orr PT, Beardall J. Photosynthetic characteristics of two Cylindrospermopsis raciborskii strains differing in their toxicity. JOURNAL OF PHYCOLOGY 2014; 50:292-302. [PMID: 26988186 DOI: 10.1111/jpy.12157] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 10/27/2013] [Indexed: 06/05/2023]
Abstract
We studied the growth and photosynthetic characteristics of a toxic (CS506) and a nontoxic strain (CS509) of the bloom-forming cyanobacterium Cylindrospermopsis raciborskii grown under identical experimental conditions. When exposed to light-saturating growth conditions (100 μmol photons · m(-2) · s(-1) ), values for maximal photosynthetic capacity (Pmax ) and maximum quantum yield (Fv /Fm ) indicated that both strains had an equal ability to process captured photons and deliver them to PSII reaction centers. However, CS506 grew faster than CS509. This was consistent with its higher light requirement for saturation of photosynthesis (Ik ). Greater shade tolerance of CS509 was indicated by its higher ability to harvest light (α), lower photosynthetic light compensation point (Ic ), and higher chlorophyll a to biovolume ratio. Strain-specific differences were found in relation to non-photochemical quenching, effective absorption cross-sectional area of PSIIα-centers (σPSIIα), and the antenna connectivity parameter of PSIIα (Jcon PSIIα). These findings highlighted differences in the transfer of excitation from phycobilisome/PSII to PSI, on the dependence on different pigments for light harvesting and on the functioning of the PSII reaction centers between the two strains. The results of this study showed that both performance and composition of the photosynthetic apparatus are different between these strains, though with only two strains examined we cannot attribute the performance of strain 506 to its ability to produce cylindrospermopsins. The emphasis on a strain-specific light adaptation/acclimation is crucial to our understanding of how different light conditions (both quantity and quality) can trigger the occurrence of different C. raciborskii strains and control their competition and/or dominance in natural ecosystems.
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Affiliation(s)
- Mattia Pierangelini
- School of Biological Science, Monash University, Clayton, Victoria, 3800, Australia
| | - Slobodanka Stojkovic
- School of Biological Science, Monash University, Clayton, Victoria, 3800, Australia
- CSIRO Marine and Atmospheric Research, Hobart, Tasmania, Australia
| | - Philip T Orr
- School of Biological Science, Monash University, Clayton, Victoria, 3800, Australia
- Seqwater, PO Box 16146, City East, Queensland, 4002, Australia
| | - John Beardall
- School of Biological Science, Monash University, Clayton, Victoria, 3800, Australia
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Ihnken S, Kromkamp JC, Beardall J, Silsbe GM. State-transitions facilitate robust quantum yields and cause an over-estimation of electron transport in Dunaliella tertiolecta cells held at the CO₂ compensation point and re-supplied with DIC. PHOTOSYNTHESIS RESEARCH 2014; 119:257-272. [PMID: 24135997 DOI: 10.1007/s11120-013-9937-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 10/01/2013] [Indexed: 06/02/2023]
Abstract
Photosynthetic energy consumption and non-photosynthetic energy quenching processes are inherently linked. Both processes must be controlled by the cell to allow cell maintenance and growth, but also to avoid photodamage. We used the chlorophyte algae Dunaliella tertiolecta to investigate how the interactive regulation of photosynthetic and non-photosynthetic pathways varies along dissolved inorganic carbon (DIC) and photon flux gradients. Specifically, cells were transferred to DIC-deplete media to reach a CO₂ compensation before being re-supplied with DIC at various concentrations and different photon flux levels. Throughout these experiments we monitored and characterized the photophysiological responses using pulse amplitude modulated fluorescence, oxygen evolution, 77 K fluorescence emission spectra, and fast-repetition rate fluorometry. O₂ uptake was not significantly stimulated at DIC depletion, which suggests that O₂ production rates correspond to assimilatory photosynthesis. Fluorescence-based measures of relative electron transport rates (rETRs) over-estimated oxygen-based photosynthetic measures due to a strong state-transitional response that facilitated high effective quantum yields. Adoption of an alternative fluorescence-based rETR calculation that accounts for state-transitions resulted in improved linear oxygen versus rETR correlation. This study shows the extraordinary capacity of D. tertiolecta to maintain stable effective quantum yields by flexible regulation of state-transitions. Uncertainties about the control mechanisms of state-transitions are presented.
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Affiliation(s)
- Sven Ihnken
- Netherlands Institute for Sea Research, NIOZ, Postbus 140, 4400 AC, Yerseke, The Netherlands
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Ogawa T, Harada T, Ozaki H, Sonoike K. Disruption of the ndhF1 Gene Affects Chl Fluorescence through State Transition in the Cyanobacterium Synechocystis sp. PCC 6803, Resulting in Apparent High Efficiency of Photosynthesis. ACTA ACUST UNITED AC 2013; 54:1164-71. [DOI: 10.1093/pcp/pct068] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Wang Z, Dong J, Li D. Conformational changes in photosynthetic pigment proteins on thylakoid membranes can lead to fast non-photochemical quenching in cyanobacteria. SCIENCE CHINA-LIFE SCIENCES 2012; 55:726-34. [DOI: 10.1007/s11427-012-4360-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 06/22/2012] [Indexed: 10/27/2022]
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Remarkably fast and selective aromatization of Hantzsch esters with MoOCl4 and MoCl5: A chemical model for possible biologically relevant properties of molybdenum-containing enzymes. Bioorg Med Chem Lett 2012; 22:3676-81. [DOI: 10.1016/j.bmcl.2012.04.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 04/06/2012] [Accepted: 04/07/2012] [Indexed: 11/15/2022]
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Chen Z, Lu G, Chen S, Chen X. LIGHT DEPENDENCY OF PHOTOSYNTHETIC RECOVERY DURING WETTING AND THE ACCLIMATION OF PHOTOSYNTHETIC APPARATUS TO LIGHT FLUCTUATION IN A TERRESTRIAL CYANOBACTERIUM NOSTOC COMMUNE(1). JOURNAL OF PHYCOLOGY 2011; 47:1063-1071. [PMID: 27020188 DOI: 10.1111/j.1529-8817.2011.01033.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The PSII photochemical activity in a terrestrial cyanobacterium Nostoc commune Vaucher ex Bornet et Flahault during rewetting was undetectable in the dark but was immediately recognized in the light. The maximum quantum yield of PSII (Fv /Fm ) during rewetting in the light rose to 85% of the maximum within ∼30 min and slowly reached the maximum within 6 h, while with rewetting in the darkness for 6 h and then exposure to light the recovery of Fv /Fm required only ∼3 min. These results suggested that recovery of photochemical activity might depend on two processes, light dependence and light independence, and the activation of photosynthetic recovery in the initial phase was severely light dependent. The inhibitor experiments showed that the recovery of Fv /Fm was not affected by chloramphenicol (CMP), but severely inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) in the light, suggesting that the light-dependent recovery of photochemical activity did not require de novo protein synthesis but required activation of PSII associated with electron flow to plastoquinone. Furthermore, the test indicated that the lower light intensity and the red light were of benefit to its activation of photochemical activity. In an outdoor experiment of diurnal changes of photochemical activity, our results showed that PSII photochemical activity was sensitive to light fluctuation, and the nonphotochemical quenching (NPQ) was rapidly enhanced at noon. Furthermore, the test suggested that the repair of PSII by de novo protein synthesis played an important role in the acclimation of photosynthetic apparatus to high light, and the heavily cloudy day was more beneficial for maintaining high photochemical activity.
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Affiliation(s)
- Zhen Chen
- College of Life Sciences and Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Hubei Normal University, Huangshi, Hubei, China 435002
| | - GaoFei Lu
- College of Life Sciences and Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Hubei Normal University, Huangshi, Hubei, China 435002
| | - Shuo Chen
- College of Life Sciences and Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Hubei Normal University, Huangshi, Hubei, China 435002
| | - XiongWen Chen
- College of Life Sciences and Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Hubei Normal University, Huangshi, Hubei, China 435002
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Khan ZI, Ahmad K, Ashraf M, Raza N, Sher M. Assessment of molybdenum status in soil and forage for ruminant production under semiarid environmental conditions in Sargodha, Pakistan. Biol Trace Elem Res 2011; 142:465-70. [PMID: 20734241 DOI: 10.1007/s12011-010-8808-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 08/05/2010] [Indexed: 11/25/2022]
Abstract
The present investigation was carried out to determine the molybdenum (Mo) status of soil and forage at the Livestock Experimental Station, Khizer abad, Sargodha, Pakistan. This site falls under semiarid climatic conditions. Soil and forage samples were collected on a monthly basis during the winter season (from October through January) and analyzed after wet digestion to determine the effect of sampling intervals on Mo content as well as its transfer from soil to forage during the whole study period. The effect of sampling intervals on soil Mo content was found to be highly significant, but in contrast, this effect on forage Mo was nonsignificant. The Mo content of soil was found to be highly sufficient to meet the requirement of forage crops, whereas those of forage at the borderline of the ruminant requirement is insufficient. It is expected that with time, further depletion of Mo in the pasture soil due to interaction with Cu and other antagonistic elements may take place, which could finally lower Mo levels in the forage being used for rearing livestock. Thus, at some stage in the future, addition of standard fertilizers enriched with Mo to the soils may be required at the livestock farm.
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Affiliation(s)
- Zafar Iqbal Khan
- Department of Biological Sciences, University of Sargodha, Sargodha 40100, Pakistan.
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38
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Evaluation of encapsulation stress and the effect of additives on viability and photosynthetic activity of Synechocystis sp. PCC 6803 encapsulated in silica gel. Appl Microbiol Biotechnol 2011; 91:1633-46. [DOI: 10.1007/s00253-011-3517-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/13/2011] [Accepted: 07/25/2011] [Indexed: 12/01/2022]
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Ohad I, Raanan H, Keren N, Tchernov D, Kaplan A. Light-induced changes within photosystem II protects Microcoleus sp. in biological desert sand crusts against excess light. PLoS One 2010; 5:e11000. [PMID: 20544016 PMCID: PMC2882322 DOI: 10.1371/journal.pone.0011000] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 05/16/2010] [Indexed: 12/16/2022] Open
Abstract
The filamentous cyanobacterium Microcoleus vaginatus, a major primary producer in desert biological sand crusts, is exposed to frequent hydration (by early morning dew) followed by desiccation during potentially damaging excess light conditions. Nevertheless, its photosynthetic machinery is hardly affected by high light, unlike “model” organisms whereby light-induced oxidative stress leads to photoinactivation of the oxygen-evolving photosystem II (PSII). Field experiments showed a dramatic decline in the fluorescence yield with rising light intensity in both drying and artificially maintained wet plots. Laboratory experiments showed that, contrary to “model” organisms, photosynthesis persists in Microcoleus sp. even at light intensities 2–3 times higher than required to saturate oxygen evolution. This is despite an extensive loss (85–90%) of variable fluorescence and thermoluminescence, representing radiative PSII charge recombination that promotes the generation of damaging singlet oxygen. Light induced loss of variable fluorescence is not inhibited by the electron transfer inhibitors 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 2,5-dibromo-3-methyl-6-isopropylbenzoquinone (DBMIB), nor the uncoupler carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), thus indicating that reduction of plastoquinone or O2, or lumen acidification essential for non-photochemical quenching (NPQ) are not involved. The rate of QA− re-oxidation in the presence of DCMU is enhanced with time and intensity of illumination. The difference in temperatures required for maximal thermoluminescence emissions from S2/QA− (Q band, 22°C) and S2,3/QB− (B band, 25°C) charge recombinations is considerably smaller in Microcoleus as compared to “model” photosynthetic organisms, thus indicating a significant alteration of the S2/QA− redox potential. We propose that enhancement of non-radiative charge recombination with rising light intensity may reduce harmful radiative recombination events thereby lowering 1O2 generation and oxidative photodamage under excess illumination. This effective photo-protective mechanism was apparently lost during the evolution from the ancestor cyanobacteria to the higher plant chloroplast.
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Affiliation(s)
- Itzhak Ohad
- Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Irael
| | - Hagai Raanan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nir Keren
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dan Tchernov
- The Interuniversity Institute for Marine Sciences in Eilat, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
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ApcD is necessary for efficient energy transfer from phycobilisomes to photosystem I and helps to prevent photoinhibition in the cyanobacterium Synechococcus sp. PCC 7002. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1122-8. [DOI: 10.1016/j.bbabio.2009.04.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 04/14/2009] [Accepted: 04/15/2009] [Indexed: 11/18/2022]
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41
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ApcD is required for state transition but not involved in blue-light induced quenching in the cyanobacterium Anabaena sp. PCC7120. Sci Bull (Beijing) 2008. [DOI: 10.1007/s11434-008-0482-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Papageorgiou GC, Tsimilli-Michael M, Stamatakis K. The fast and slow kinetics of chlorophyll a fluorescence induction in plants, algae and cyanobacteria: a viewpoint. PHOTOSYNTHESIS RESEARCH 2007; 94:275-90. [PMID: 17665151 DOI: 10.1007/s11120-007-9193-x] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 05/03/2007] [Indexed: 05/16/2023]
Abstract
The light-induced/dark-reversible changes in the chlorophyll (Chl) a fluorescence of photosynthetic cells and membranes in the mus-to-several min time window (fluorescence induction, FI; or Kautsky transient) reflect quantum yield changes (quenching/de-quenching) as well as changes in the number of Chls a in photosystem II (PS II; state transitions). Both relate to excitation trapping in PS II and the ensuing photosynthetic electron transport (PSET), and to secondary PSET effects, such as ion translocation across thylakoid membranes and filling or depletion of post-PS II and post-PS I pools of metabolites. In addition, high actinic light doses may depress Chl a fluorescence irreversibly (photoinhibitory lowering; q(I)). FI has been studied quite extensively in plants an algae (less so in cyanobacteria) as it affords a low resolution panoramic view of the photosynthesis process. Total FI comprises two transients, a fast initial (OPS; for Origin, Peak, Steady state) and a second slower transient (SMT; for Steady state, Maximum, Terminal state), whose details are characteristically different in eukaryotic (plants and algae) and prokaryotic (cyanobacteria) oxygenic photosynthetic organisms. In the former, maximal fluorescence output occurs at peak P, with peak M lying much lower or being absent, in which case the PSMT phases are replaced by a monotonous PT fluorescence decay. In contrast, in phycobilisome (PBS)-containing cyanobacteria maximal fluorescence occurs at M which lies much higher than peak P. It will be argued that this difference is caused by a fluorescence lowering trend (state 1 --> 2 transition) that dominates the FI pattern of plants and algae, and correspondingly by a fluorescence increasing trend (state 2 --> 1 transition) that dominates the FI of PBS-containing cyanobacteria. Characteristically, however, the FI pattern of the PBS-minus cyanobacterium Acaryochloris marina resembles the FI patterns of algae and plants and not of the PBS-containing cyanobacteria.
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Affiliation(s)
- George C Papageorgiou
- National Center for Scientific Research Demokritos, Institute of Biology, Athens, 153 10, Greece.
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Ray K, Debeer George S, Solomon EI, Wieghardt K, Neese F. Description of the ground-state covalencies of the bis(dithiolato) transition-metal complexes from X-ray absorption spectroscopy and time-dependent density-functional calculations. Chemistry 2007; 13:2783-97. [PMID: 17290468 DOI: 10.1002/chem.200601425] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The electronic structures of [M(L(Bu))(2)](-) (L(Bu)=3,5-di-tert-butyl-1,2-benzenedithiol; M=Ni, Pd, Pt, Cu, Co, Au) complexes and their electrochemically generated oxidized and reduced forms have been investigated by using sulfur K-edge as well as metal K- and L-edge X-ray absorption spectroscopy. The electronic structure content of the sulfur K-edge spectra was determined through detailed comparison of experimental and theoretically calculated spectra. The calculations were based on a new simplified scheme based on quasi-relativistic time-dependent density functional theory (TD-DFT) and proved to be successful in the interpretation of the experimental data. It is shown that dithiolene ligands act as noninnocent ligands that are readily oxidized to the dithiosemiquinonate(-) forms. The extent of electron transfer strongly depends on the effective nuclear charge of the central metal, which in turn is influenced by its formal oxidation state, its position in the periodic table, and scalar relativistic effects for the heavier metals. Thus, the complexes [M(L(Bu))(2)](-) (M=Ni, Pd, Pt) and [Au(L(Bu))(2)] are best described as delocalized class III mixed-valence ligand radicals bound to low-spin d(8) central metal ions while [M(L(Bu))(2)](-) (M=Cu, Au) and [M(L(Bu))(2)](2-) (M=Ni, Pd, Pt) contain completely reduced dithiolato(2-) ligands. The case of [Co(L(Bu))(2)](-) remains ambiguous. On the methodological side, the calculation led to the new result that the transition dipole moment integral is noticeably different for S(1s)-->valence-pi versus S(1s)-->valence-sigma transitions, which is explained on the basis of the differences in radial distortion that accompany chemical bond formation. This is of importance in determining experimental covalencies for complexes with highly covalent metal-sulfur bonds from ligand K-edge absorption spectroscopy.
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Affiliation(s)
- Kallol Ray
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
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Sandström S, Park YI, Öquist G, Gustafsson P. CP43′, the isiA Gene Product, Functions as an Excitation Energy Dissipator in the Cyanobacterium Synechococcus sp. PCC 7942¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740431ctigpf2.0.co2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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45
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Ma W, Ogawa T, Shen Y, Mi H. Changes in cyclic and respiratory electron transport by the movement of phycobilisomes in the cyanobacterium Synechocystis sp. strain PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:742-9. [PMID: 17336920 DOI: 10.1016/j.bbabio.2007.01.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 01/17/2007] [Accepted: 01/23/2007] [Indexed: 12/01/2022]
Abstract
Phycobilisomes (PBS) are the major accessory light-harvesting complexes in cyanobacteria and their mobility affects the light energy distribution between the two photosystems. We investigated the effect of PBS mobility on state transitions, photosynthetic and respiratory electron transport, and various fluorescence parameters in Synechocystis sp. strain PCC 6803, using glycinebetaine to immobilize and couple PBS to photosystem II (PSII) or photosystem I (PSI) by applying under far-red or green light, respectively. The immobilization of PBS at PSII inhibited the increase in cyclic electron flow, photochemical and non-photochemical quenching, and decrease in respiration that occurred during the movement of PBS from PSII to PSI. In contrast, the immobilization of PBS at PSI inhibited the increase in respiration and photochemical quenching and decrease in cyclic electron flow and non-photochemical quenching that occurred when PBS moved from PSI to PSII. Linear electron transport did not change during PBS movement but increased or decreased significantly during longer illumination with far-red or green light, respectively. This implies that PBS movement is completed in a short time but it takes longer for the overall photosynthetic reactions to be tuned to a new state.
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Affiliation(s)
- Weimin Ma
- National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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Ray K, Petrenko T, Wieghardt K, Neese F. Joint spectroscopic and theoretical investigations of transition metal complexes involving non-innocent ligands. Dalton Trans 2007:1552-66. [PMID: 17426855 DOI: 10.1039/b700096k] [Citation(s) in RCA: 268] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of transition metal complexes involving non-innocent o-dithiolene and o-phenylenediamine ligands has been characterized in detail by various spectroscopic methods like magnetic circular dichroism (MCD), absorption (abs), resonance Raman (rR), electron paramagnetic resonance (EPR), and sulfur K-edge X-ray absorption spectroscopies. A computational model for the electronic structure of the complexes is then proposed based on the density functional theory (DFT) or ab-initio methods, which can successfully account for the observed trends in the experimental spectra (MCD, rR, and abs) of the complexes. Based on these studies, the innocent vs non-innocent nature of the ligands in a given transition metal complex is found to be dependent on the position of the central metal ion in the periodic table, its effective nuclear charge in interplay with relativistic effects.
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Affiliation(s)
- Kallol Ray
- Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
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47
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di Rigano VM, Vona V, Lobosco O, Carillo P, Lunn JE, Carfagna S, Esposito S, Caiazzo M, Rigano C. Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana. PLANT, CELL & ENVIRONMENT 2006; 29:1400-9. [PMID: 17080961 DOI: 10.1111/j.1365-3040.2006.01523.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Temperature responses of nitrate reductase (NR) were studied in the psychrophilic unicellular alga, Koliella antarctica, and in the mesophilic species, Chlorella sorokiniana. Enzymes from both species were purified to near homogeneity by Blue Sepharose (Pharmacia, Uppsala, Sweden) affinity chromatography and high-resolution anion-exchange chromatography (MonoQ; Pharmacia; Uppsala, Sweden). Both enzymes have a subunit molecular mass of 100 kDa, and K. antarctica NR has a native molecular mass of 367 kDa. NR from K. antarctica used both NADPH and NADH, whereas NR from C. sorokiniana used NADH only. Both NRs used reduced methyl viologen (MVH) or benzyl viologen (BVH). In crude extracts, maximal NADH and MVH-dependent activities of cryophilic NR were found at 15 and 35 degrees C, respectively, and retained 77 and 62% of maximal activity, respectively, at 10 degrees C. Maximal NADH and MVH-dependent activities of mesophilic NR, however, were found at 25 and 45 degrees C, respectively, with only 33 and 23% of maximal activities being retained at 10 degrees C. In presence of 2 microM flavin adenine dinucleotide (FAD), activities of cryophilic NADH:NR and mesophilic NADH:NR were stable up to 25 and 35 degrees C, respectively. Arrhenius plots constructed with cryophilic and mesophilic MVH:NR rate constants, in both presence or absence of FAD, showed break points at 15 and 25 degrees C, respectively. Essentially, similar results were obtained for purified enzymes and for activities measured in crude extracts. Factors by which the rate increases by raising temperature 10 degrees C (Q10) and apparent activation energy (E(a)) values for NADH and MVH activities measured in enzyme preparations without added FAD differed slightly from those measured with FAD. Overall thermal features of the NADH and MVH activities of the cryophilic NR, including optimal temperatures, heat inactivation (with/without added FAD) and break-point temperature in Arrhenius plots, are all shifted by about 10 degrees C towards lower temperatures than those of the mesophilic enzyme. Transfer of electrons from NADH to nitrate occurs via all three redox centres within NR molecule, whereas transfer from MVH requires Mo-pterin prosthetic group only; therefore, our results strongly suggest that structural modification(s) for cold adaptation affect thermodynamic properties of each of the functional domains within NR holoenzyme in equal measure.
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Affiliation(s)
- Vittoria Martino di Rigano
- Dipartimento di Farmacologia Sperimentale, Università di Napoli Federico II, Via Montesano 49 I-80131 Napoli, Italy
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Singh R, Chauhan SMS. Electron transfer in natural and unnatural flavoporphyrins. Bioorg Chem 2004; 32:140-69. [PMID: 15110193 DOI: 10.1016/j.bioorg.2003.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2003] [Indexed: 11/24/2022]
Abstract
The development of chemical models for enzymes and their chemical and physical studies constitutes an important area of research from a scientific as well as an industrial point of view. Covalently linked flavin and porphyrin (flavoporphyrins) have attracted attention due to their applications as chemical models for flavoproteins and related enzymes. In this review, the literature has been surveyed to provide a comprehensive coverage of the synthetic methodology and characterization techniques of various types of synthetic flavoporphyrins.
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Affiliation(s)
- Ram Singh
- Department of Chemistry, University of Delhi, Delhi 110 007, India.
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Beutler M, Wiltshire KH, Arp M, Kruse J, Reineke C, Moldaenke C, Hansen UP. A reduced model of the fluorescence from the cyanobacterial photosynthetic apparatus designed for the in situ detection of cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1604:33-46. [PMID: 12686419 DOI: 10.1016/s0005-2728(03)00022-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Fluorometric determination of the chlorophyll (Chl) content of cyanobacteria is impeded by the unique structure of their photosynthetic apparatus, i.e., the phycobilisomes (PBSs) in the light-harvesting antennae. The problems are caused by the variations in the ratio of the pigment PC to Chl a resulting from adaptation to varying environmental conditions. In order to include cyanobacteria in fluorometric analysis of algae, a simplified energy distribution model describing energy pathways in the cyanobacterial photosynthetic apparatus was conceptualized. Two sets of mathematical equations were derived from this model and tested. Fluorescence of cyanobacteria was measured with a new fluorometer at seven excitation wavelength ranges and at three detection channels (650, 685 and 720 nm) in vivo. By employing a new fit procedure, we were able to correct for variations in the cyanobacterial fluorescence excitation spectra and to account for other phytoplankton signals. The effect of energy-state transitions on the PC fluorescence emission of PBSs was documented. The additional use of the PC fluorescence signal in combination with our recently developed mathematical approach for phytoplankton analysis based on Chl fluorescence spectroscopy allows a more detailed study of cyanobacteria and other phytoplankton in vivo and in situ.
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Affiliation(s)
- M Beutler
- Max-Planck-Institut (MPI) für Limnologie, Plön, Germany.
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Sandström S, Ivanov AG, Park YI, Oquist G, Gustafsson P. Iron stress responses in the cyanobacterium Synechococcus sp. PCC7942. PHYSIOLOGIA PLANTARUM 2002; 116:255-263. [PMID: 12354203 DOI: 10.1034/j.1399-3054.2002.1160216.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In the present study, we describe the sequential events by which the cyanobacterium Synechococcus sp. PCC 7942 adapts to iron deficiency. In doing so, we have tried to elucidate both short and long-term acclimation to low iron stress in order to understand how the photosynthetic apparatus adjusts to low iron conditions. Our results show that after an initial step, where CP43' is induced and where ferredoxin is partly replaced by flavodoxin, the photosynthetic unit starts to undergo major rearrangements. All measured components of Photosystem I (PSI), PSII and cytochrome (Cyt) f decrease relative to chlorophyll (Chl) a. The photochemical efficiencies of the two photosystems also decline during this phase of acclimation. The well-known drop in phycobilisome content measured as phycocyanin (PC)/Chl was not due to an increased degradation, but rather to a decreased rate of synthesis. The largest effects of iron deficiency were observed on PSI, the most iron-rich structure of the photosynthetic apparatus. In the light of the recent discovery of an iron deficiency induced CP43' ring around PSI a possible dual function of this protein as both an antenna and a quencher is discussed. We also describe the time course of a blue shift in the low temperature Chl emission peak around 715 nm, which originates in PSI. The shift might reflect the disassembly and/or degradation of PSI during iron deficiency and, as a consequence, PSI might under these conditions be found predominantly in a monomeric form. We suggest that the observed functional and compositional alterations represent cellular acclimation enabling growth and development under iron deficiency, and that growth ceases when the acclimation capacity is exhausted. However, the cells remain viable even after growth has ceased, since they resumed growth once iron was added back to the culture.
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Affiliation(s)
- Stefan Sandström
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, S-90187 Umeå, Sweden Department of Plant Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada Department of Biology, Chungnam National University, Taejon 305-764, Korea
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