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Nikkanen L, Vakal S, Hubáček M, Santana-Sánchez A, Konert G, Wang Y, Boehm M, Gutekunst K, Salminen TA, Allahverdiyeva Y. Flavodiiron proteins associate pH-dependently with the thylakoid membrane for ferredoxin-1-powered O 2 photoreduction. THE NEW PHYTOLOGIST 2025; 246:2084-2101. [PMID: 40178019 DOI: 10.1111/nph.70114] [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: 11/11/2024] [Accepted: 03/10/2025] [Indexed: 04/05/2025]
Abstract
Flavodiiron proteins (FDPs) catalyse light-dependent reduction of oxygen to water in photosynthetic organisms, creating an electron sink on the acceptor side of Photosystem I that protects the photosynthetic apparatus. However, ambiguity about the electron donor(s) remains, and the molecular mechanisms regulating FDP activity have remained elusive. We employed spectroscopic and gas flux analysis of photosynthetic electron transport, bimolecular fluorescence complementation assays for in vivo protein-protein interactions in the model cyanobacterium Synechocystis sp. PCC 6803, and in silico surface charge modelling. We demonstrated that ferredoxin-1 interacts with Flv1, Flv2, and Flv3, and is the main electron donor to FDP heterooligomers, which are responsible for the photoreduction of oxygen. Moreover, we revealed that FDP heterooligomers dissociate from the thylakoid membrane upon alkalisation of the cytosol, providing the first in vivo evidence of a self-regulatory feedback mechanism allowing dynamic control of FDP activity and maintenance of photosynthetic redox balance in fluctuating environments. Our findings have direct implications for rationally directing electron flux towards desired reactions in biotechnological applications.
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Affiliation(s)
- Lauri Nikkanen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Serhii Vakal
- Faculty of Science and Engineering, Structural Bioinformatics Laboratory and InFLAMES Research Flagship Center, Åbo Akademi University, Turku, FI-20520, Finland
| | - Michal Hubáček
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Anita Santana-Sánchez
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Grzegorz Konert
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Yingying Wang
- Botanical Institute, Plant Cell Physiology and Biotechnology, University of Kiel, Kiel, D-24118, Germany
| | - Marko Boehm
- Molecular Plant Physiology, University of Kassel, Kassel, D-34132, Germany
| | - Kirstin Gutekunst
- Botanical Institute, Plant Cell Physiology and Biotechnology, University of Kiel, Kiel, D-24118, Germany
- Molecular Plant Physiology, University of Kassel, Kassel, D-34132, Germany
| | - Tiina A Salminen
- Faculty of Science and Engineering, Structural Bioinformatics Laboratory and InFLAMES Research Flagship Center, Åbo Akademi University, Turku, FI-20520, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
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Pohland AC, Bernát G, Geimer S, Schneider D. Mg 2+ limitation leads to a decrease in chlorophyll, resulting in an unbalanced photosynthetic apparatus in the cyanobacterium Synechocytis sp. PCC6803. PHOTOSYNTHESIS RESEARCH 2024; 162:13-27. [PMID: 39037691 DOI: 10.1007/s11120-024-01112-7] [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: 04/26/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024]
Abstract
Mg2+, the most abundant divalent cation in living cells, plays a pivotal role in numerous enzymatic reactions and is of particular importance for organisms performing oxygenic photosynthesis. Its significance extends beyond serving as the central ion of the chlorophyll molecule, as it also acts as a counterion during the light reaction to balance the proton gradient across the thylakoid membranes. In this study, we investigated the effects of Mg2+ limitation on the physiology of the well-known model microorganism Synechocystis sp. PCC6803. Our findings reveal that Mg2+ deficiency triggers both morphological and functional changes. As seen in other oxygenic photosynthetic organisms, Mg2+ deficiency led to a decrease in cellular chlorophyll concentration. Moreover, the PSI-to-PSII ratio decreased, impacting the photosynthetic efficiency of the cell. In line with this, Mg2+ deficiency led to a change in the proton gradient built up across the thylakoid membrane upon illumination.
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Affiliation(s)
- Anne-Christin Pohland
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, Mainz, 55128, Germany
- HUN-REN Balaton Limnological Research Institute, Tihany, Hungary
| | - Gábor Bernát
- HUN-REN Balaton Limnological Research Institute, Tihany, Hungary
| | - Stefan Geimer
- Cell Biology and Electron Microscopy, University of Bayreuth, Bayreuth, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, Mainz, 55128, Germany.
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany.
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3
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Mohamadpour F, Amani AM. Photocatalytic systems: reactions, mechanism, and applications. RSC Adv 2024; 14:20609-20645. [PMID: 38952944 PMCID: PMC11215501 DOI: 10.1039/d4ra03259d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 06/21/2024] [Indexed: 07/03/2024] Open
Abstract
The photocatalytic field revolves around the utilization of photon energy to initiate various chemical reactions using non-adsorbing substrates, through processes such as single electron transfer, energy transfer, or atom transfer. The efficiency of this field depends on the capacity of a light-absorbing metal complex, organic molecule, or substance (commonly referred to as photocatalysts or PCs) to execute these processes. Photoredox techniques utilize photocatalysts, which possess the essential characteristic of functioning as both an oxidizing and a reducing agent upon activation. In addition, it is commonly observed that photocatalysts exhibit optimal performance when irradiated with low-energy light sources, while still retaining their catalytic activity under ambient temperatures. The implementation of photoredox catalysis has resuscitated an array of synthesis realms, including but not limited to radical chemistry and photochemistry, ultimately affording prospects for the development of the reactions. Also, photoredox catalysis is utilized to resolve numerous challenges encountered in medicinal chemistry, as well as natural product synthesis. Moreover, its applications extend across diverse domains encompassing organic chemistry and catalysis. The significance of photoredox catalysts is rooted in their utilization across various fields, including biomedicine, environmental pollution management, and water purification. Of course, recently, research has evaluated photocatalysts in terms of cost, recyclability, and pollution of some photocatalysts and dyes from an environmental point of view. According to these new studies, there is a need for critical studies and reviews on photocatalysts and photocatalytic processes to provide a solution to reduce these limitations. As a future perspective for research on photocatalysts, it is necessary to put the goals of researchers on studies to overcome the limitations of the application and efficiency of photocatalysts to promote their use on a large scale for the development of industrial activities. Given the significant implications of the subject matter, this review seeks to delve into the fundamental tenets of the photocatalyst domain and its associated practical use cases. This review endeavors to demonstrate the prospective of a powerful tool known as photochemical catalysis and elucidate its underlying tenets. Additionally, another goal of this review is to expound upon the various applications of photocatalysts.
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Affiliation(s)
- Farzaneh Mohamadpour
- Department of Medical Nanotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences Shiraz Iran
| | - Ali Mohammad Amani
- Department of Medical Nanotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences Shiraz Iran
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Gates C, Williams JM, Ananyev G, Dismukes GC. How chloride functions to enable proton conduction in photosynthetic water oxidation: Time-resolved kinetics of intermediates (S-states) in vivo and bromide substitution. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148998. [PMID: 37499962 DOI: 10.1016/j.bbabio.2023.148998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/11/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023]
Abstract
Chloride (Cl-) is essential for O2 evolution during photosynthetic water oxidation. Two chlorides near the water-oxidizing complex (WOC) in Photosystem II (PSII) structures from Thermosynechococcus elongatus (and T. vulcanus) have been postulated to transfer protons generated from water oxidation. We monitored four criteria: primary charge separation flash yield (P* → P+QA-), rates of water oxidation steps (S-states), rate of proton evolution, and flash O2 yield oscillations by measuring chlorophyll variable fluorescence (P* quenching), pH-sensitive dye changes, and oximetry. Br-substitution slows and destabilizes cellular growth, resulting from lower light-saturated O2 evolution rate (-20 %) and proton release (-36 % ΔpH gradient). The latter implies less ATP production. In Br- cultures, protonogenic S-state transitions (S2 → S3 → S0') slow with increasing light intensity and during O2/water exchange (S0' → S0 → S1), while the non-protonogenic S1 → S2 transition is kinetically unaffected. As flash rate increases in Cl- cultures, both rate and extent of acidification of the lumen increase, while charge recombination is suppressed relative to Br-. The Cl- advantage in rapid proton escape from the WOC to lumen is attributed to correlated ion-pair movement of H3O+Cl- in dry water channels vs. separated Br- and H+ ion movement through different regions (>200-fold difference in Bronsted acidities). By contrast, at low flash rates a previously unreported reversal occurs that favors Br- cultures for both proton evolution and less PSII charge recombination. In Br- cultures, slower proton transfer rate is attributed to stronger ion-pairing of Br- with AA residues lining the water channels. Both anions charge-neutralize protons and shepherd them to the lumen using dry aqueous channels.
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Affiliation(s)
- Colin Gates
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Computational Biology and Molecular Biophysics, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Biochemistry, Loyola University Chicago, IL 60660, USA
| | - Jonah M Williams
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, NJ 08854, USA
| | - Gennady Ananyev
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, NJ 08854, USA
| | - G Charles Dismukes
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, NJ 08854, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, NJ 08854, USA.
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Mohamadpour F. A Facile Access to Metal-Free Synthesis of 3,4-Dihydropyrimidin-2-(1 H)-Ones/Thiones using Acridine Yellow G as a Photo-Induced Electron Transfer Photocatalyst. Polycycl Aromat Compd 2023. [DOI: 10.1080/10406638.2023.2176524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Mohamadpour F. Acridine yellow G (AYG) as a photo-induced electron transfer (PET) photocatalyst employed for the radical Michael-Mannich cyclocondensation of imines. Front Chem 2022; 10:1015330. [PMID: 36300032 PMCID: PMC9590109 DOI: 10.3389/fchem.2022.1015330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
A four-component domino Michael-Mannich cyclocondensation of amines, dialkyl acetylenedicarboxylaes, and formaldehyde was utilized to develop a green technique for sans metal combination of polyfunctionalized dihydro-2-oxypyrroles. It involves visible light as an environmentally friendly power source and acridine yellow G (AYG) as a photo-induced electron transfer (PET) photocatalyst. The motivation behind this examination was to expand the utilization of a non-metal dye that is both reasonable and broadly accessible. Photochemically catalyzed AYG flaunts exceptional returns, energy effectiveness, and natural agreeableness, as well as extraordinary iota economy, efficient highlights, and comfort of purpose. Key abilities consist of an easy experimental setup, big substrate tolerance, finance-friendly, clean painting-up strategies within the absence of tedious separation techniques, and minimized the quantity of waste for each organic transformation. The type of yields is pretty uniform (85-97%, average 92.09%), and the shape of reaction times might be very speedy (15-30 min, average 21.59 min), and the factor stated inside the dialogue is that the method tolerates quite a number electron-donating and electron-withdrawing functional groups, while, however, giving extremely good yields. The response within the reason is insensitive to the person of the substituents. Subsequently, many compounds and natural factors can be followed over the course of time. Shockingly, gram-scale cyclization is conceivable, proposing that the strategy could be utilized in industry.
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Cyclic Electron Flow-Coupled Proton Pumping in Synechocystis sp. PCC6803 Is Dependent upon NADPH Oxidation by the Soluble Isoform of Ferredoxin:NADP-Oxidoreductase. Microorganisms 2022; 10:microorganisms10050855. [PMID: 35630303 PMCID: PMC9144156 DOI: 10.3390/microorganisms10050855] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/13/2022] [Accepted: 04/20/2022] [Indexed: 11/17/2022] Open
Abstract
Ferredoxin:NADP-oxidoreductase (FNR) catalyzes the reversible exchange of electrons between ferredoxin (Fd) and NADP(H). Reduction of NADP+ by Fd via FNR is essential in the terminal steps of photosynthetic electron transfer, as light-activated electron flow produces NADPH for CO2 assimilation. FNR also catalyzes the reverse reaction in photosynthetic organisms, transferring electrons from NADPH to Fd, which is important in cyanobacteria for respiration and cyclic electron flow (CEF). The cyanobacterium Synechocystis sp. PCC6803 possesses two isoforms of FNR, a large form attached to the phycobilisome (FNRL) and a small form that is soluble (FNRS). While both isoforms are capable of NADPH oxidation or NADP+ reduction, FNRL is most abundant during typical growth conditions, whereas FNRS accumulates under stressful conditions that require enhanced CEF. Because CEF-driven proton pumping in the light–dark transition is due to NDH-1 complex activity and they are powered by reduced Fd, CEF-driven proton pumping and the redox state of the PQ and NADP(H) pools were investigated in mutants possessing either FNRL or FNRS. We found that the FNRS isoform facilitates proton pumping in the dark–light transition, contributing more to CEF than FNRL. FNRL is capable of providing reducing power for CEF-driven proton pumping, but only after an adaptation period to illumination. The results support that FNRS is indeed associated with increased cyclic electron flow and proton pumping, which is consistent with the idea that stress conditions create a higher demand for ATP relative to NADPH.
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8
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Melnikov AG, Bykov DA, Varezhnikov AS, Sysoev VV, Melnikov GV. Toward a Selective Analysis of Heavy Metal Salts in Aqueous Media with a Fluorescent Probe Array. SENSORS (BASEL, SWITZERLAND) 2022; 22:1465. [PMID: 35214366 PMCID: PMC8878195 DOI: 10.3390/s22041465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/03/2022] [Accepted: 02/10/2022] [Indexed: 11/16/2022]
Abstract
Detection of heavy meals in aqueous media challenges worldwide research in developing particularly fast and affordable methods. Fluorescent sensors look to be an appropriate instrument for such a task, as recently they have been found to have made large progress in the detection of chemical analytes, primarily in the environment, along with biological fluids, which still suffer from not enough selectivity. In this work, we propose a new fluorescent method to selectively recognize heavy metals in an aqueous solution via employing an array of several fluorescent probes: acridine yellow, eosin, and methylene blue, which were taken as examples, being sensitive to a microsurrounding of the probe molecules. The exemplary sensor array generated six channels of spectral information through the use of various combinations of excitation and detection wavelengths. Following the known multisensor approach, we applied a linear discriminant analysis to selectively distinguish the vector signals from the sensor array from salts of heavy metals-Cu, Pb, Zn, Cd, and Cz-at the concentration ranges of 2.41 × 10-6-1.07 × 10-5 M, 2.8 × 10-5-5.87 × 10-4 M, 1.46 × 10-6-6.46 × 10-6 M, 1.17 × 10-8-5.2 × 10-8 M, and 2.11 × 10-6-9.33 × 10-6 M, respectively. The suggested approach was found to be promising due to it employing only one cuvette containing the test solution, simplifying a sample preparation when compared to preparing a variety of solutions in tests with single fluorescence probes.
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Affiliation(s)
- Andrey G. Melnikov
- Department of Physics, Yuri Gagarin State Technical University of Saratov, 410054 Saratov, Russia; (D.A.B.); (A.S.V.); (G.V.M.)
| | | | | | - Victor V. Sysoev
- Department of Physics, Yuri Gagarin State Technical University of Saratov, 410054 Saratov, Russia; (D.A.B.); (A.S.V.); (G.V.M.)
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Kostjukova LO, Leontieva SV, Kostjukov VV. The vibronic absorption spectra and electronic states of acridine yellow in aqueous solution. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Brandenburg F, Theodosiou E, Bertelmann C, Grund M, Klähn S, Schmid A, Krömer JO. Trans-4-hydroxy-L-proline production by the cyanobacterium Synechocystis sp. PCC 6803. Metab Eng Commun 2020; 12:e00155. [PMID: 33511031 PMCID: PMC7815826 DOI: 10.1016/j.mec.2020.e00155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 11/30/2020] [Accepted: 12/11/2020] [Indexed: 01/21/2023] Open
Abstract
Cyanobacteria play an important role in photobiotechnology. Yet, one of their key central metabolic pathways, the tricarboxylic acid (TCA) cycle, has a unique architecture compared to most heterotrophs and still remains largely unexploited. The conversion of 2-oxoglutarate to succinate via succinyl-CoA is absent but is by-passed by several other reactions. Overall, fluxes under photoautotrophic growth conditions through the TCA cycle are low, which has implications for the production of chemicals. In this study, we investigate the capacity of the TCA cycle of Synechocystis sp PCC 6803 for the production of trans-4-hydroxy-L-proline (Hyp), a valuable chiral building block for the pharmaceutical and cosmetic industries. For the first time, photoautotrophic Hyp production was achieved in a cyanobacterium expressing the gene for the L-proline-4-hydroxylase (P4H) from Dactylosporangium sp. strain RH1. Interestingly, while elevated intracellular Hyp concentrations could be detected in the recombinant Synechocystis strains under all tested conditions, detectable Hyp secretion into the medium was only observed when the pH of the medium exceeded 9.5 and mostly in the late phases of the cultivation. We compared the rates obtained for autotrophic Hyp production with published sugar-based production rates in E. coli. The land-use efficiency (space-time yield) of the phototrophic process is already in the same order of magnitude as the heterotrophic process considering sugar farming as well. But, the remarkable plasticity of the cyanobacterial TCA cycle promises the potential for a 23–55 fold increase in space-time yield when using Synechocystis. Altogether, these findings contribute to a better understanding of bioproduction from the TCA cycle in photoautotrophs and broaden the spectrum of chemicals produced in metabolically engineered cyanobacteria. Phototrophic production of trans-4-hydroxy-L-prolin. pH dependency of product accumulation in Synechocystis PCC6803. Comparative analysis of land use efficiency in phototrophs & heterotrophs.
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El‐Gamal S, Ismail AM. Electrical and optical properties of novel brilliant cresyl blue dye‐doped poly(methyl methacrylate)as selective cut‐offlaser filters. POLYM INT 2020. [DOI: 10.1002/pi.6082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- S El‐Gamal
- Physics Department, Faculty of Science Northern Border University Arar Kingdom of Saudi Arabia
- Physics Department, Faculty of Education Ain Shams University Cairo Egypt
| | - A M Ismail
- Physics Department, Faculty of Education Ain Shams University Cairo Egypt
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12
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Pohland AC, Schneider D. Mg2+ homeostasis and transport in cyanobacteria - at the crossroads of bacterial and chloroplast Mg2+ import. Biol Chem 2020; 400:1289-1301. [PMID: 30913030 DOI: 10.1515/hsz-2018-0476] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/19/2019] [Indexed: 12/29/2022]
Abstract
Magnesium cation (Mg2+) is the most abundant divalent cation in living cells, where it is required for various intracellular functions. In chloroplasts and cyanobacteria, established photosynthetic model systems, Mg2+ is the central ion in chlorophylls, and Mg2+ flux across the thylakoid membrane is required for counterbalancing the light-induced generation of a ΔpH across the thylakoid membrane. Yet, not much is known about Mg2+ homoeostasis, transport and distribution within cyanobacteria. However, Mg2+ transport across membranes has been studied in non-photosynthetic bacteria, and first observations and findings are reported for chloroplasts. Cyanobacterial cytoplasmic membranes appear to contain the well-characterized Mg2+ channels CorA and/or MgtE, which both facilitate transmembrane Mg2+ flux down the electrochemical gradient. Both Mg2+ channels are typical for non-photosynthetic bacteria. Furthermore, Mg2+ transporters of the MgtA/B family are also present in the cytoplasmic membrane to mediate active Mg2+ import into the bacterial cell. While the cytoplasmic membrane of cyanobacteria resembles a 'classical' bacterial membrane, essentially nothing is known about Mg2+ channels and/or transporters in thylakoid membranes of cyanobacteria or chloroplasts. As discussed here, at least one Mg2+ channelling protein must be localized within thylakoid membranes. Thus, either one of the 'typical' bacterial Mg2+ channels has a dual localization in the cytoplasmic plus the thylakoid membrane, or another, yet unidentified channel is present in cyanobacterial thylakoid membranes.
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Affiliation(s)
- Anne-Christin Pohland
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
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Liran O, Shemesh E, Tchernov D. Investigation into the CO2 concentrating step rates within the carbon concentrating mechanism of Synechocystis sp. PCC6803 at various pH and light intensities reveal novel mechanistic properties. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Tibiletti T, Rehman AU, Vass I, Funk C. The stress-induced SCP/HLIP family of small light-harvesting-like proteins (ScpABCDE) protects Photosystem II from photoinhibitory damages in the cyanobacterium Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 2018; 135:103-114. [PMID: 28795265 PMCID: PMC5783992 DOI: 10.1007/s11120-017-0426-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/22/2017] [Indexed: 05/07/2023]
Abstract
Small CAB-like proteins (SCPs) are single-helix light-harvesting-like proteins found in all organisms performing oxygenic photosynthesis. We investigated the effect of growth in moderate salt stress on these stress-induced proteins in the cyanobacterium Synechocystis sp. PCC 6803 depleted of Photosystem I (PSI), which expresses SCPs constitutively, and compared these cells with a PSI-less/ScpABCDE- mutant. SCPs, by stabilizing chlorophyll-binding proteins and Photosystem II (PSII) assembly, protect PSII from photoinhibitory damages, and in their absence electrons accumulate and will lead to ROS formation. The presence of 0.2 M NaCl in the growth medium increased the respiratory activity and other PSII electron sinks in the PSI-less/ScpABCDE- strain. We postulate that this salt-induced effect consumes the excess of PSII-generated electrons, reduces the pressure of the electron transport chain, and thereby prevents 1O2 production.
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Affiliation(s)
- Tania Tibiletti
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden
- SC Synchrotron SOLEIL, AILES beamline, L'Orme des Merisiers Saint-Aubin- BP 48, 91192, Gif-sur-Yvette, France
| | - Ateeq Ur Rehman
- Institute of Plant Biology, Biological Research Center, Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Center, Szeged, Hungary
| | - Christiane Funk
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden.
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El-Khouly ME, El-Mohsnawy E, Fukuzumi S. Solar energy conversion: From natural to artificial photosynthesis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2017. [DOI: 10.1016/j.jphotochemrev.2017.02.001] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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16
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Han X, Sun N, Xu M, Mi H. Co-ordination of NDH and Cup proteins in CO2 uptake in cyanobacterium Synechocystis sp. PCC 6803. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3869-3877. [PMID: 28911053 PMCID: PMC5853218 DOI: 10.1093/jxb/erx129] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/30/2017] [Indexed: 05/24/2023]
Abstract
High and low affinity CO2-uptake systems containing CupA (NDH-1MS) and CupB (NDH-1MS'), respectively, have been identified in Synechocystis sp. PCC 6803, but it is yet unknown how the complexes function in CO2 uptake. In this work, we found that deletion of cupB significantly lowered the growth of cells, and deletion of both cupA and cupB seriously suppressed the growth below pH 7.0 even under 3% CO2. The rate of photosynthetic oxygen evolution was decreased slightly by deletion of cupA but significantly by deletion of cupB and more severely by deletion of both cupA and cupB, especially in response to changed pH conditions under 3% CO2. Furthermore, we found that assembly of CupB into NDH-1MS' was dependent on NdhD4 and NdhF4. NDH-1MS' was not affected in the NDH-1MS-degradation mutant and NDH-1MS was not affected in the NDH-1MS'-degradation mutants, indicating the existence of independent CO2-uptake systems under high CO2 conditions. The light-induced proton gradient across thylakoid membranes was significantly inhibited in ndhD-deletion mutants, suggesting that NdhDs functions in proton pumping. The carbonic anhydrase activity was suppressed partly in the cupA- or cupB-deletion mutant but severely in the mutant with both cupA and cupB deletion, indicating that CupA and CupB function in conversion of CO2 to HCO3-. In turn, deletion of cup genes lowered the transthylakoid membrane proton gradient and deletion of ndhDs decreased the CO2 hydration. Our results suggest that NDH-1M provides an alkaline region to activate Cup proteins involved in CO2 uptake.
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Affiliation(s)
- Xunling Han
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Nan Sun
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Min Xu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai, China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai, China
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NdhV subunit regulates the activity of type-1 NAD(P)H dehydrogenase under high light conditions in cyanobacterium Synechocystis sp. PCC 6803. Sci Rep 2016; 6:28361. [PMID: 27329499 PMCID: PMC4916593 DOI: 10.1038/srep28361] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/01/2016] [Indexed: 12/25/2022] Open
Abstract
The cyanobacterial NAD(P)H dehydrogenase (NDH-1) complexes play crucial roles in variety of bioenergetic reactions. However, the regulative mechanism of NDH-1 under stressed conditions is still unclear. In this study, we detected that the NDH-1 activity is partially impaired, but the accumulation of NDH-1 complexes was little affected in the NdhV deleted mutant (ΔndhV) at low light in cyanobacterium Synechocystis sp. PCC 6803. ΔndhV grew normally at low light but slowly at high light under inorganic carbon limitation conditions (low pH or low CO2), meanwhile the activity of CO2 uptake was evidently lowered than wild type even at pH 8.0. The accumulation of NdhV in thylakoids strictly relies on the presence of the hydrophilic subcomplex of NDH-1. Furthermore, NdhV was co-located with hydrophilic subunits of NDH-1 loosely associated with the NDH-1L, NDH-1MS' and NDH-1M complexes. The level of the NdhV was significantly increased at high light and deletion of NdhV suppressed the up-regulation of NDH-1 activity, causing the lowered the photosynthetic oxygen evolution at pH 6.5 and high light. These data indicate that NdhV is an intrinsic subunit of hydrophilic subcomplex of NDH-1, required for efficient operation of cyclic electron transport around photosystem I and CO2 uptake at high lights.
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Herdean A, Teardo E, Nilsson AK, Pfeil BE, Johansson ON, Ünnep R, Nagy G, Zsiros O, Dana S, Solymosi K, Garab G, Szabó I, Spetea C, Lundin B. A voltage-dependent chloride channel fine-tunes photosynthesis in plants. Nat Commun 2016; 7:11654. [PMID: 27216227 PMCID: PMC4890181 DOI: 10.1038/ncomms11654] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/16/2016] [Indexed: 11/17/2022] Open
Abstract
In natural habitats, plants frequently experience rapid changes in the intensity of sunlight. To cope with these changes and maximize growth, plants adjust photosynthetic light utilization in electron transport and photoprotective mechanisms. This involves a proton motive force (PMF) across the thylakoid membrane, postulated to be affected by unknown anion (Cl(-)) channels. Here we report that a bestrophin-like protein from Arabidopsis thaliana functions as a voltage-dependent Cl(-) channel in electrophysiological experiments. AtVCCN1 localizes to the thylakoid membrane, and fine-tunes PMF by anion influx into the lumen during illumination, adjusting electron transport and the photoprotective mechanisms. The activity of AtVCCN1 accelerates the activation of photoprotective mechanisms on sudden shifts to high light. Our results reveal that AtVCCN1, a member of a conserved anion channel family, acts as an early component in the rapid adjustment of photosynthesis in variable light environments.
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Affiliation(s)
- Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Enrico Teardo
- Department of Biology, University of Padova, Padova 35121, Italy
| | - Anders K. Nilsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Bernard E. Pfeil
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Oskar N. Johansson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Renáta Ünnep
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest 1121, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest 1121, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged 6701, Hungary
| | - Somnath Dana
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Katalin Solymosi
- Department of Plant Anatomy, Eötvös Loránd University, Budapest 1117, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged 6701, Hungary
| | - Ildikó Szabó
- Department of Biology, University of Padova, Padova 35121, Italy
- CNR Neuroscience Institute, Padova 35121, Italy
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Björn Lundin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
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Stamatakis K, Papageorgiou GC. ΔpH-dependent non-photochemical quenching (qE) of excited chlorophylls in the photosystem II core complex of the freshwater cyanobacterium Synechococcus sp PCC 7942. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 81:184-189. [PMID: 24793104 DOI: 10.1016/j.plaphy.2014.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
Light-induced and lumen acidity-dependent quenching (qE) of excited chlorophylls (Chl) in vivo has been amply documented in plants and algae, but not in cyanobacteria, using primarily the saturation pulse method of quenching analysis which is applied to continuously illuminated samples. This method is unsuitable for cyanobacteria because the background illumination elicits in them a very large Chl a fluorescence signal, due to a state 2 to state 1 transition, which masks fluorescence changes due to other causes. We investigated the qE problem in the cyanobacterium Synechococcus sp. PCC 7942 using a kinetic method (Chl a fluorescence induction) with which qE can be examined before the onset of the state 2 to state 1 transition and the attendant rise of Chl a fluorescence. Our results confirm the existence of a qE mechanism that operates on excited Chls a in Photosystem II core complexes of cyanobacteria.
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Affiliation(s)
- Kostas Stamatakis
- Institute of Biosciences and Applications, National Center for Scientific Research Demokritos, Aghia Paraskevi Attikis 15310, Greece.
| | - George C Papageorgiou
- Institute of Biosciences and Applications, National Center for Scientific Research Demokritos, Aghia Paraskevi Attikis 15310, Greece
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20
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Checchetto V, Teardo E, Carraretto L, Formentin E, Bergantino E, Giacometti GM, Szabo I. Regulation of photosynthesis by ion channels in cyanobacteria and higher plants. Biophys Chem 2013; 182:51-7. [PMID: 23891570 DOI: 10.1016/j.bpc.2013.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 11/25/2022]
Abstract
Photosynthesis converts light energy into chemical energy, and supplies ATP and NADPH for CO2 fixation into carbohydrates and for the synthesis of several compounds which are essential for autotrophic growth. Oxygenic photosynthesis takes place in thylakoid membranes of chloroplasts and photosynthetic prokaryote cyanobacteria. An ancestral photoautotrophic prokaryote related to cyanobacteria has been proposed to give rise to chloroplasts of plants and algae through an endosymbiotic event. Indeed, photosynthetic complexes involved in the electron transport coupled to H(+) translocation and ATP synthesis are similar in higher plants and cyanobacteria. Furthermore, some of the protein and solute/ion conducting machineries also share common structure and function. Electrophysiological and biochemical evidence support the existence of ion channels in the thylakoid membrane in both types of organisms. By allowing specific ion fluxes across thylakoid membranes, ion channels have been hypothesized to either directly or indirectly regulate photosynthesis, by modulating the proton motive force. Recent molecular identification of some of the thylakoid-located channels allowed to obtain genetic proof in favor of such hypothesis. Furthermore, some ion channels of the envelope membrane in chloroplasts have also been shown to impact on this light-driven process. Here we give an overview of thylakoid/chloroplast located ion channels of higher plants and of cyanobacterium Synechocystis sp. PCC 6803. We focus on channels shown to be implicated in the regulation of photosynthesis and discuss the possible mechanisms of action.
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Affiliation(s)
- Vanessa Checchetto
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
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21
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Tikhonov AN. Energetic and regulatory role of proton potential in chloroplasts. BIOCHEMISTRY (MOSCOW) 2012; 77:956-74. [DOI: 10.1134/s0006297912090027] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Thylakoid potassium channel is required for efficient photosynthesis in cyanobacteria. Proc Natl Acad Sci U S A 2012; 109:11043-8. [PMID: 22711813 DOI: 10.1073/pnas.1205960109] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A potassium channel (SynK) of the cyanobacterium Synechocystis sp. PCC 6803, a photoheterotrophic model organism for the study of photosynthesis, has been recently identified and demonstrated to function as a potassium selective channel when expressed in a heterologous system and to be located predominantly to the thylakoid membrane in cyanobacteria. To study its physiological role, a SynK-less knockout mutant was generated and characterized. Fluorimetric experiments indicated that SynK-less cyanobacteria cannot build up a proton gradient as efficiently as WT organisms, suggesting that SynK might be involved in the regulation of the electric component of the proton motive force. Accordingly, measurements of flash-induced cytochrome b(6)f turnover and respiration pointed to a reduced generation of ΔpH and to an altered linear electron transport in mutant cells. The lack of the channel did not cause an altered membrane organization, but decreased growth and modified the photosystem II/photosystem I ratio at high light intensities because of enhanced photosensitivity. These data shed light on the function of a prokaryotic potassium channel and reports evidence, by means of a genetic approach, on the requirement of a thylakoid ion channel for optimal photosynthesis.
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23
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Madrakian T, Afkhami A, Ahmadi M, Bagheri H. Removal of some cationic dyes from aqueous solutions using magnetic-modified multi-walled carbon nanotubes. JOURNAL OF HAZARDOUS MATERIALS 2011; 196:109-14. [PMID: 21930344 DOI: 10.1016/j.jhazmat.2011.08.078] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 08/30/2011] [Accepted: 08/31/2011] [Indexed: 05/15/2023]
Abstract
An adsorbent, magnetic-modified multi-walled carbon nanotubes, was used for removal of cationic dyes crystal violet (CV), thionine (Th), janus green B (JG), and methylene blue (MB) from water samples. Prepared nanoparticles were characterized by SEM, TEM, BET and XRD measurements. The prepared magnetic adsorbent can be well dispersed in the water and easily separated magnetically from the medium after loaded with adsorbate. The influences of parameters including initial pH, dosage of adsorbent and contact time have been investigated in order to find the optimum adsorption conditions. The optimum pH for removing of all the investigated cationic dyes from water solutions was found to be 7.0. The experimental data were analyzed by the Langmuir adsorption model. The maximum predicted adsorption capacities for CV, JG, Th and MB dyes were obtained as 227.7, 250.0, 36.4 and 48.1 mg g(-1), respectively. Desorption process of the adsorbed cationic dyes was also investigated using acetonitrile as the solvent. It was notable that both the adsorption and desorption of dyes were quite fast probably due to the absence of internal diffusion resistance.
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24
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Imashimizu M, Bernát G, Sunamura EI, Broekmans M, Konno H, Isato K, Rögner M, Hisabori T. Regulation of F0F1-ATPase from Synechocystis sp. PCC 6803 by gamma and epsilon subunits is significant for light/dark adaptation. J Biol Chem 2011; 286:26595-26602. [PMID: 21610078 PMCID: PMC3143624 DOI: 10.1074/jbc.m111.234138] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/02/2011] [Indexed: 12/07/2024] Open
Abstract
The γ and ε subunits of F(0)F(1)-ATP synthase from photosynthetic organisms display unique properties not found in other organisms. Although the γ subunit of both chloroplast and cyanobacterial F(0)F(1) contains an extra amino acid segment whose deletion results in a high ATP hydrolysis activity (Sunamura, E., Konno, H., Imashimizu-Kobayashi, M., Sugano, Y., and Hisabori, T. (2010) Plant Cell Physiol. 51, 855-865), its ε subunit strongly inhibits ATP hydrolysis activity. To understand the physiological significance of these phenomena, we studied mutant strains with (i) a C-terminally truncated ε (ε(ΔC)), (ii) γ lacking the inserted sequence (γ(Δ198-222)), and (iii) a double mutation of (i) and (ii) in Synechocystis sp. PCC 6803. Although thylakoid membranes from the ε(ΔC) strain showed higher ATP hydrolysis and lower ATP synthesis activities than those of the wild type, no significant difference was observed in growth rate and in intracellular ATP level both under light conditions and during light-dark cycles. However, both the ε(ΔC) and γ(Δ198-222) and the double mutant strains showed a lower intracellular ATP level and lower cell viability under prolonged dark incubation compared with the wild type. These data suggest that internal inhibition of ATP hydrolysis activity is very important for cyanobacteria that are exposed to prolonged dark adaptation and, in general, for the survival of photosynthetic organisms in an ever-changing environment.
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Affiliation(s)
- Mari Imashimizu
- From the Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan and
| | - Gábor Bernát
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Ei-Ichiro Sunamura
- From the Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan and
| | - Martin Broekmans
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Hiroki Konno
- From the Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan and
| | - Kota Isato
- From the Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan and
| | - Matthias Rögner
- Department of Plant Biochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Toru Hisabori
- From the Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan and
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25
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Schultze M, Forberich B, Rexroth S, Dyczmons NG, Roegner M, Appel J. Localization of cytochrome b6f complexes implies an incomplete respiratory chain in cytoplasmic membranes of the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1479-85. [PMID: 19577535 DOI: 10.1016/j.bbabio.2009.06.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2008] [Revised: 06/19/2009] [Accepted: 06/23/2009] [Indexed: 11/24/2022]
Abstract
The cytochrome b(6)f complex is an integral part of the photosynthetic and respiratory electron transfer chain of oxygenic photosynthetic bacteria. The core of this complex is composed of four subunits, cytochrome b, cytochrome f, subunit IV and the Rieske protein (PetC). In this study deletion mutants of all three petC genes of Synechocystis sp. PCC 6803 were constructed to investigate their localization, involvement in electron transfer, respiration and photohydrogen evolution. Immunoblots revealed that PetC1, PetC2, and all other core subunits were exclusively localized in the thylakoids, while the third Rieske protein (PetC3) was the only subunit found in the cytoplasmic membrane. Deletion of petC3 and both of the quinol oxidases failed to elicit a change in respiration rate, when compared to the respective oxidase mutant. This supports a different function of PetC3 other than respiratory electron transfer. We conclude that the cytoplasmic membrane of Synechocystis lacks both a cytochrome c oxidase and the cytochrome b(6)f complex and present a model for the major electron transfer pathways in the two membranes of Synechocystis. In this model there is no proton pumping electron transfer complex in the cytoplasmic membrane. Cyclic electron transfer was impaired in all petC1 mutants. Nonetheless, hydrogenase activity and photohydrogen evolution of all mutants were similar to wild type cells. A reduced linear electron transfer and an increased quinol oxidase activity seem to counteract an increased hydrogen evolution in this case. This adds further support to the close interplay between the cytochrome bd oxidase and the bidirectional hydrogenase.
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Affiliation(s)
- Matthias Schultze
- Botanisches Institut, Christian-Albrechts-Universität, 24118 Kiel, Germany
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26
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Ghica ME, Brett CM. Poly(brilliant cresyl blue) modified glassy carbon electrodes: Electrosynthesis, characterisation and application in biosensors. J Electroanal Chem (Lausanne) 2009. [DOI: 10.1016/j.jelechem.2009.01.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Bernát G, Waschewski N, Rögner M. Towards efficient hydrogen production: the impact of antenna size and external factors on electron transport dynamics in Synechocystis PCC 6803. PHOTOSYNTHESIS RESEARCH 2009; 99:205-16. [PMID: 19137411 DOI: 10.1007/s11120-008-9398-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Accepted: 12/23/2008] [Indexed: 05/12/2023]
Abstract
Three Synechocystis PCC 6803 strains with different levels of phycobilisome antenna-deficiency have been investigated for their impact on photosynthetic electron transport and response to environmental factors (i.e. light-quality, -quantity and composition of growth media). Oxygen yield and P(700) reduction kinetic measurements showed enhanced linear electron transport rates-especially under photoautotrophic conditions-with impaired antenna-size, starting from wild type (WT) (full antenna) over DeltaapcE- (phycobilisomes functionally dissociated) and Olive (lacking phycocyanin) up to the PAL mutant (lacking the whole phycobilisome). In contrast to mixotrophic conditions (up to 80% contribution), cyclic electron transport plays only a minor role (below 10%) under photoautotrophic conditions for all the strains, while linear electron transport increased up to 5.5-fold from WT to PAL mutant. The minor contribution of the cyclic electron transport was proportionally increased with the linear one in the DeltaapcE and Olive mutant, but was not altered in the PAL mutant, indicating that upregulation of the linear route does not have to be correlated with downregulation of the cyclic electron transport. Antenna-deficiency involves higher linear electron transport rates by tuning the PS2/PS1 ratio from 1:5 in WT up to 1:1 in the PAL mutant. While state transitions were observed only in the WT and Olive mutant, a further ~30% increase in the PS2/PS1 ratio was achieved in all the strains by long-term adaptation to far red light (720 nm). These results are discussed in the context of using these cells for future H(2) production in direct combination with the photosynthetic electron transport and suggest both Olive and PAL as potential candidates for future manipulations toward this goal. In conclusion, the highest rates can be expected if mutants deficient in phycobilisome antennas are grown under photoautotrophic conditions in combination with uncoupling of electron transport and an illumination which excites preferably PS1.
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Affiliation(s)
- Gábor Bernát
- Lehrstuhl für Biochemie der Pflanzen, Ruhr Universität Bochum, 44780, Bochum, Germany.
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28
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Zhang R, Xie J, Zhao J. The mobility of PSI and PQ molecules in Spirulina platensis cells during state transition. PHOTOSYNTHESIS RESEARCH 2009; 99:107-113. [PMID: 19140024 DOI: 10.1007/s11120-008-9400-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 12/23/2008] [Indexed: 05/27/2023]
Abstract
Monomerization and trimerization of photosystem I (PSI) in cyanobacteria are reversible to response to light switched off and on, which leads to "energy spillover" to regulate excitation of the two photosystems in balance. Considering that PSI is a trans-membrane protein embedded in thylakoid membranes, the monomerization or trimerization must involve a movement of PSI in the membranes. In this work, the mobility of PSI was demonstrated by dependence of the monomerization and trimerization on temperature for intact Spirulina platensis cells undergoing a light-to-dark or a dark-to-light transition. Based on the characteristic absorbance of monomers and trimmers, it confirms that both monomerization and trimerization are temperature-sensitive. The relative populations of the monomers and trimmers are invariable above the phase transition temperature (T (PT)) while directly proportional to temperature below T (PT). On the other hand, the rate to reach the equilibrium population is proportional to temperature above T (PT) but invariable below T (PT). The PSI mobility and the temperature-dependent population are contrary to those of plastoquinone (PQ) molecules because PSI is a trans-membrane protein while PQ molecules are small diffusive electron carriers in thylakoid membranes as well as their distinctive sizes and environments. The less monomerization of PSI but the invariable time constant at lower temperature below T (PT) may be due to that accumulation of the reduced PQ molecules results in decrease of the stromal-side H(+) concentration which is a driving force of PSI monomerization.
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Affiliation(s)
- Rui Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, People's Republic of China
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29
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Xu M, Bernát G, Singh A, Mi H, Rögner M, Pakrasi HB, Ogawa T. Properties of Mutants of Synechocystis sp. Strain PCC 6803 Lacking Inorganic Carbon Sequestration Systems. ACTA ACUST UNITED AC 2008; 49:1672-7. [DOI: 10.1093/pcp/pcn139] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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30
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Hydrogen ions directly regulating the oligomerization state of Photosystem I in intact Spirulina platensis cells. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11434-008-0064-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Lee S, Ryu JY, Kim SY, Jeon JH, Song JY, Cho HT, Choi SB, Choi D, de Marsac NT, Park YI. Transcriptional regulation of the respiratory genes in the cyanobacterium Synechocystis sp. PCC 6803 during the early response to glucose feeding. PLANT PHYSIOLOGY 2007; 145:1018-30. [PMID: 17827271 PMCID: PMC2048796 DOI: 10.1104/pp.107.105023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The coordinated expression of the genes involved in respiration in the photosynthetic cyanobacterium Synechocystis sp. PCC 6803 during the early period of glucose (Glc) treatment is poorly understood. When photoautotrophically grown cells were supplemented with 10 mm Glc in the light or after a dark adaptation period of 14 h, significant increases in the respiratory activity, as determined by NAD(P)H turnover, respiratory O(2) uptake rate, and cytosolic alkalization, were observed. At the same time, the transcript levels of 18 genes coding for enzymes associated with respiration increased with differential induction kinetics; these genes were classified into three groups based on their half-rising times. Transcript levels of the four genes gpi, zwf, pdhB, and atpB started to increase along with a net increase in NAD(P)H, while the onset of net NAD(P)H consumption coincided with an increase in those of the genes tktA, ppc, pdhD, icd, ndhD2, ndbA, ctaD1, cydA, and atpE. In contrast, the expression of the atpI/G/D/A/C genes coding for ATP synthase subunits was the slowest among respiratory genes and their expression started to accumulate only after the establishment of cytosolic alkalization. These differential effects of Glc on the transcript levels of respiratory genes were not observed by inactivation of the genes encoding the Glc transporter or glucokinase. In addition, several Glc analogs could not mimic the effects of Glc. Our findings suggest that genes encoding some enzymes involved in central carbon metabolism and oxidative phosphorylation are coordinately regulated at the transcriptional level during the switch of nutritional mode.
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Affiliation(s)
- Sanghyeob Lee
- Laboratory of Plant Genomics, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
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Abstract
Most organisms maintain a transmembrane sodium gradient for cell function. Despite the importance of Na(+) in physiology, no directly Na(+)-responsive signalling molecules are known. The CyaB1 and CyaB2 adenylyl cyclases of the cyanobacterium Anabaena PCC 7120 are inhibited by Na(+). A D360A mutation in the GAF-B domain of CyaB1 ablated cAMP-mediated autoregulation and Na(+) inhibition. Na(+) bound the isolated GAF domains of CyaB2. cAMP blocked Na(+) binding to GAF domains but Na(+) had no effect on cAMP binding. Na(+) altered GAF domain structure indicating a mechanism of inhibition independent of cAMP binding. DeltacyaB1 and DeltacyaB2 mutant strains did not grow below 0.6 mM Na(+) and DeltacyaB1 cells possessed defects in Na(+)/H(+) antiporter function. Replacement of the CyaB1 GAF domains with those of rat phosphodiesterase type 2 revealed that Na(+) inhibition has been conserved since the eukaryotic/bacterial divergence. CyaB1 and CyaB2 are the first identified directly Na(+)-responsive signalling molecules that function in sodium homeostasis and we propose a subset of GAF domains underpin an evolutionarily conserved Na(+) signalling mechanism.
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Affiliation(s)
- Martin Cann
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham, UK.
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33
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Fu PKL, Abuzakhm S, Turro C. Photoinduced DNA Cleavage and Cellular Damage in Human Dermal Fibroblasts by 2,3-Diaminophenazine¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01526.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Li H, Li D, Yang S, Xie J, Zhao J. The state transition mechanism—simply depending on light-on and -off in Spirulina platensis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1512-9. [PMID: 17014821 DOI: 10.1016/j.bbabio.2006.08.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 08/21/2006] [Accepted: 08/22/2006] [Indexed: 11/20/2022]
Abstract
The state transition in cyanobacteria is a long-discussed topic of how the photosynthetic machine regulates the excitation energy distribution in balance between the two photosystems. In the current work, whether the state transition is realized by "mobile phycobilisome (PBS)" or "energy spillover" has been clearly answered by monitoring the spectral responses of the intact cells of the cyanobacterium Spirulina platensis. Firstly, light-induced state transition depends completely on a movement of PBSs toward PSI or PSII while the redox-induced one on not only the "mobile PBS" but also an "energy spillover". Secondly, the "energy spillover" is triggered by dissociation of PSI trimers into the monomers which specially occurs under a case from light to dark, while the PSI monomers will re-aggregate into the trimers under a case from dark to light, i.e., the PSI oligomerization is reversibly regulated by light switch on and off. Thirdly, PSI oligomerization is regulated by the local H(+) concentration on the cytosol side of the thylakoid membranes, which in turn is regulated by light switch on and off. Fourthly, PSI oligomerization change is the only mechanism for the "energy spillover". Thus, it can be concluded that the "mobile PBS" is a common rule for light-induced state transition while the "energy spillover" is only a special case when dark condition is involved.
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Affiliation(s)
- Heng Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), Photochemistry Laboratory, P. O. Box 101, Institute of Chemistry, Chinese Academy of Sciences, No. 2, 1st North Street, Zhongguancun, Beijing, 100080, P. R. China
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35
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Berry S, Fischer JH, Kruip J, Hauser M, Wildner GF. Monitoring cytosolic pH of carboxysome-deficient cells of Synechocystis sp. PCC 6803 using fluorescence analysis. PLANT BIOLOGY (STUTTGART, GERMANY) 2005; 7:342-7. [PMID: 16025406 DOI: 10.1055/s-2005-837710] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Disruption of the ccmM gene in the cyanobacterium Synechocystis sp. PCC 6803 causes a deficiency of carboxysomes and impairs growth in ambient CO2. The effect of this gene defect on cellular metabolism was investigated using electron microscopy, biochemical and fluorescence analysis. Mutant cells were devoid of the characteristic dense polyhedral bodies called carboxysomes. The photosynthetic oxygen evolution was considerably lower in mutant cells compared to wild type, while Rubisco activity in cell extracts was similar. During photosynthetic CO2-dependent oxygen evolution, Rubisco Vmax dropped from 142 micromol mg-1 chlorophyll h-1 (WT) to 77 micromol mg-1 chlorophyll h-1 in the mutant cells, and the Km for Ci (inorganic carbon) increased from 0.5 mM (WT) to 40 mM. The fluorescent indicator, acridine yellow, was used for non-invasive measurements of cytoplasmic pH changes in whole cells induced by addition of Ci, making use of the decrease in fluorescence yield that accompanies cytoplasmic acidification. The experimental results indicate that control of the cytoplasmic pH is linked to the internal carbon pool (Ci). Both wild-type and ccmM-deficient cells showed a linear response of acridine yellow fluorescence quenching and, thus, of internal acidification, with respect to externally added inorganic carbon. However, the fluorescence analysis of mutant (carboxysome-free) cells indicated slower kinetics of Ci accumulation.
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Affiliation(s)
- S Berry
- Lehrstuhl für Biochemie der Pflanzen, Ruhr-Universität Bochum, 44780 Bochum, Germany
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36
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Tychinsky VP, Kretushev AV, Vyshenskaya TV, Tikhonov AN. Coherent phase microscopy in cell biology: visualization of metabolic states. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:362-6. [PMID: 15950927 DOI: 10.1016/j.bbabio.2005.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Accepted: 04/27/2005] [Indexed: 11/25/2022]
Abstract
Visualization of functional properties of individual cells and intracellular organelles still remains an experimental challenge in cell biology. The coherent phase microscopy (CPM) provides a convenient and non-invasive tool for imaging cells and intracellular organelles. In this work, we report results of statistical analysis of CPM images of cyanobacterial cells (Synechocystis sp. PCC 6803) and spores (Bacillus licheniformis). It has been shown that CPM images of cyanobacterial cells and spores are sensitive to variations of their metabolic states. We found a correlation between one of optical parameters of the CPM image ('phase thicknesses' Deltah) and cell energization. It was demonstrated that the phase thickness Deltah decreased after cell treatment with the uncoupler CCCP or inhibitors of electron transport (KCN or DCMU). Statistical analysis of distributions of parameter Deltah and cell diameter d demonstrated that a decrease in the phase thickness Deltah could not be attributed entirely to a decrease in geometrical sizes of cells. This finding demonstrates that the CPM technique may be a convenient tool for fast and non-invasive diagnosis of metabolic states of individual cells and intracellular organelles.
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Affiliation(s)
- Vladimir P Tychinsky
- Moscow State Institute for Radioengineering, Electronics and Automation, prosp. Vernadskogo 78, 119454 Moscow, Russia
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37
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Fu PKL, Abuzakhm S, Turro C. Photoinduced DNA Cleavage and Cellular Damage in Human Dermal Fibroblasts by 2,3-Diaminophenazine¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-07-20-ra-237.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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38
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Pogoryelov D, Sudhir PR, Kovács L, Gombos Z, Brown I, Garab G. Sodium dependency of the photosynthetic electron transport in the alkaliphilic cyanobacterium Arthrospira platensis. J Bioenerg Biomembr 2004; 35:427-37. [PMID: 14740891 DOI: 10.1023/a:1027339814544] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Arthrospira (Spirulina) platensis (A. platensis) is a model organism for investigation of adaptation of photosynthetic organisms to extreme environmental conditions: the cell functions in this cyanobacterium are optimized to high pH and high concentration (150-250 mM) of Na+. However, the mechanism of the possible fine-tuning of the photosynthetic functions to these extreme conditions and/or the regulation of the cellular environment to optimize the photosynthetic functions is poorly understood. In this work we investigated the effect of Na-ions on different photosynthetic activities: linear electron transport reactions (measured by means of polarography and spectrophotometry), the activity of photosystem II (PS II) (thermoluminescence and chlorophyll a fluorescence induction), and redox turnover of the cytochrome b6f complex (flash photolysis); and measured the changes of the intracellular pH (9-aminoacridine fluorescence). It was found that sodium deprivation of cells in the dark at pH 10 inhibited, within 40 min, all measured photosynthetic reactions, and led to an alkalinization of the intracellular pH, which rose from the physiological value of about 8.3-9.6. These were partially and totally restored by readdition of Na-ions at 2.5-25 mM and about 200 mM, respectively. The intracellular pH and the photosynthetic functions were also sensitive to monensin, an exogenous Na+/H+ exchanger, which collapses both proton and sodium gradients across the cytoplasmic membrane. These observations explain the strict Na+-dependency of the photosynthetic electron transport at high extracellular pH, provide experimental evidence on the alkalization of the intracellular environment, and support the hypothesized role of an Na+/H+ antiport through the plasma membrane in pH homeostasis (Schlesinger et al. (1996). J. Phycol. 32, 608-613). Further, we show that (i) the specific site of inactivation of the photosynthetic electron transport at alkaline pH is to be found at the water splitting enzyme; (ii) in contrast to earlier reports, the inactivation occurs in the dark and, for short periods, without detectable damage in the photosynthetic apparatus; and (iii) in contrast to high pH, Na+ dependency in the neutral pH range is shown not to originate from PSII, but from the acceptor side of PSI. These data permit us to conclude that the intracellular environment rather than the machinery of the photosynthetic electron transport is adjusted to the extreme conditions of high pH and high Na+ concentration.
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Affiliation(s)
- D Pogoryelov
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, H-6701 Szeged, P.O. Box 521, Hungary
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Ryu JY, Song JY, Lee JM, Jeong SW, Chow WS, Choi SB, Pogson BJ, Park YI. Glucose-induced Expression of Carotenoid Biosynthesis Genes in the Dark Is Mediated by Cytosolic pH in the Cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 2004; 279:25320-5. [PMID: 15078876 DOI: 10.1074/jbc.m402541200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The expression of carotenoid biosynthesis genes coding for phytoene synthase (crtB), phytoene desaturase (crtP), zeta-carotene desaturase (crtQ), and beta-carotene hydroxylase (crtR) is dependent upon light in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis). We have demonstrated that the expression of the above four genes was also elevated in the dark-adapted Synechocystis cells upon glucose treatment as a consequence of transcriptional activation. Treatment with glucose analogs such as l-glucose, 3-O-methylglucose, 2-deoxyglucose, and mannose, or inactivation of glucose uptake and phosphorylation by deletion mutation of glucose transporter (glcP) and glucokinase (gk), respectively, did not induce up-regulation of carotenoid genes. When respiratory electron transport or coupling to oxidative phosphorylation was inhibited, glucose induction was not observed, indicating that respiratory electron transport per se is not critical for the expression of these genes. In agreement with this view, the extent of gene expression showed a saturation curve with increasing acridine yellow fluorescence yield, without having a close correlation with the ATP contents or ATP/ADP ratio. The results indicate that glucose induction of carotenoid gene expressions is mediated by an increase in cytosolic pH rather than either redox or glucose sensing.
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Affiliation(s)
- Jee-Youn Ryu
- Department of Biology, Chungnam National University, Daejeon 305-764, Korea
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40
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Cowan AE, Olivastro EM, Koppel DE, Loshon CA, Setlow B, Setlow P. Lipids in the inner membrane of dormant spores of Bacillus species are largely immobile. Proc Natl Acad Sci U S A 2004; 101:7733-8. [PMID: 15126669 PMCID: PMC419675 DOI: 10.1073/pnas.0306859101] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Accepted: 04/05/2004] [Indexed: 11/18/2022] Open
Abstract
Bacterial spores of various Bacillus species are impermeable or exhibit low permeability to many compounds that readily penetrate germinated spores, including methylamine. We now show that a lipid probe in the inner membrane of dormant spores of Bacillus megaterium and Bacillus subtilis is largely immobile, as measured by fluorescence redistribution after photobleaching, but becomes free to diffuse laterally upon spore germination. The lipid immobility in and the slow permeation of methylamine through the inner membrane of dormant spores may be due to a significant (1.3- to 1.6-fold) apparent reduction of the membrane surface area in the dormant spore relative to that in the germinated spore, but is not due to the dormant spore's high levels of dipicolinic acid and divalent cations.
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Affiliation(s)
- Ann E Cowan
- Department of Molecular, Microbial, and Structural Biology and Center for Biomedical Imaging Technology, University of Connecticut Health Center, Farmington, CT 06032, USA
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41
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Berry S, Esper B, Karandashova I, Teuber M, Elanskaya I, Rögner M, Hagemann M. Potassium uptake in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803 mainly depends on a Ktr-like system encoded by slr1509 (ntpJ). FEBS Lett 2003; 548:53-8. [PMID: 12885407 DOI: 10.1016/s0014-5793(03)00729-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The molecular basis of potassium uptake in cyanobacteria has not been elucidated. However, genes known from other bacteria to encode potassium transporters can be identified in the genome of Synechocystis sp. strain PCC 6803. Mutants defective in kdpA and ntpJ were generated and characterized to address the role of the Kdp and KtrAB systems in this strain. KtrAB is crucial for K(+) uptake, as the DeltantpJ mutant shows slowed growth, slowed potassium uptake kinetics, and increased salt sensitivity. The DeltakdpA mutant has the same phenotype as the wild type even at limiting potassium, but a DeltakdpADeltantpJ double mutant is not viable, indicating a role of Kdp for potassium uptake when the Ktr system is not functioning.
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Affiliation(s)
- Stephan Berry
- LS Biochemie der Pflanzen, Ruhr-University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
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42
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Sapra R, Bagramyan K, Adams MWW. A simple energy-conserving system: proton reduction coupled to proton translocation. Proc Natl Acad Sci U S A 2003; 100:7545-50. [PMID: 12792025 PMCID: PMC164623 DOI: 10.1073/pnas.1331436100] [Citation(s) in RCA: 206] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxidative phosphorylation involves the coupling of ATP synthesis to the proton-motive force that is generated typically by a series of membrane-bound electron transfer complexes, which ultimately reduce an exogenous terminal electron acceptor. This is not the case with Pyrococcus furiosus, an archaeon that grows optimally near 100 degrees C. It has an anaerobic respiratory system that consists of a single enzyme, a membrane-bound hydrogenase. Moreover, it does not require an added electron acceptor as the enzyme reduces protons, the simplest of acceptors, to hydrogen gas by using electrons from the cytoplasmic redox protein ferredoxin. It is demonstrated that the production of hydrogen gas by membrane vesicles of P. furiosus is directly coupled to the synthesis of ATP by means of a proton-motive force that has both electrochemical and pH components. Such a respiratory system enables rationalization in this organism of an unusual glycolytic pathway that was previously thought not to conserve energy. It is now clear that the use of ferredoxin in place of the expected NAD as the electron acceptor for glyceraldehyde 3-phosphate oxidation enables energy to be conserved by hydrogen production. In addition, this simple respiratory mechanism readily explains why the growth yields of P. furiosus are much higher than could be accounted for if ATP synthesis occurred only by substrate-level phosphorylation. The ability of microorganisms such as P. furiosus to couple hydrogen production to energy conservation has important ramifications not only in the evolution of respiratory systems but also in the origin of life itself.
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Affiliation(s)
- Rajat Sapra
- Department of Biochemistry and Molecular Biology, Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602-7229, USA
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43
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Trubitsin BV, Mamedov MD, Vitukhnovskaya LA, Semenov AY, Tikhonov AN. EPR study of light-induced regulation of photosynthetic electron transport in Synechocystis sp. strain PCC 6803. FEBS Lett 2003; 544:15-20. [PMID: 12782283 DOI: 10.1016/s0014-5793(03)00429-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The kinetics of the light-induced redox changes of the photosystem 1 (PS 1) primary donor P(700) in whole cells of the cyanobacteria Synechocystis sp. PCC 6803 were studied by the electron paramagnetic resonance method. It was shown that the linear photosynthetic electron transport in cyanobacteria was controlled by two main mechanisms: (i) oxygen-dependent acceleration of electron transfer from PS 1 to NADP(+) due to activation of the Calvin cycle reactions and (ii) retardation of electron flow between two photosystems governed by a transmembrane proton gradient. In addition to the linear photosynthetic electron transport, cyanobacteria were capable of maintaining alternative pathways involving cyclic electron transfer around PS 1 and respiratory chains.
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Affiliation(s)
- Boris V Trubitsin
- Department of Biophysics, Faculty of Physics, M.V. Lomonosov Moscow State University, Russia
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44
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Wang HL, Postier BL, Burnap RL. Polymerase chain reaction-based mutageneses identify key transporters belonging to multigene families involved in Na+ and pH homeostasis of Synechocystis sp. PCC 6803. Mol Microbiol 2002; 44:1493-506. [PMID: 12067339 DOI: 10.1046/j.1365-2958.2002.02983.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Primary ion pumps and antiporters exist as multigene families in the Synechocystis sp. PCC 6803 genome and show very strong homologies to those found in higher plants. The gene knock-outs of five putative Na+/H+ antiporters (slr1727, sll0273, sll0689, slr1595 and slr0415) and seven cation ATPases (sll1614, sll1920, slr0671-72, slr0822, slr1507-08-09, slr1728- 29 and slr1950) in the model cyanobacterium (http://www.kazusa.or.jp/cyano/cyano.html) were performed in this study relying on homologous recombination with mutagenenic fragments constructed using a fusion polymerase chain reaction (PCR) approach. The impacts of these gene knock-outs were evaluated in terms of Na+ and pH, and light-induced acidification and alkalization that are asso-ciated with inorganic carbon uptake. Two of the five putative antiporter mutants exhibit a characteristic interplay between the pH and Na+ dependence of growth, but only one of the antiporters appears to be necessary for high NaCl tolerance. On the other hand, the mutation of one of the two copper-trafficking ATPases produces a cell line that shows acute NaCl sensitivity. Additionally, disruptions of a putative Ca2+-ATPase and a gene cluster encoding a putative Na+-ATPase subunit also cause high NaCl sensitivity. The findings and possible mechanisms are discussed in relation to the potential roles of these transporters in Synechocystis sp. PCC 6803.
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Affiliation(s)
- Hong-Liang Wang
- Department of Microbiology and Molecular Genetics, 307 Life Sciences East, Oklahoma State University, Stillwater, OK 74075, USA
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