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Wang L, Yang M, Guo C, Jiang Y, Zhu Z, Hu C, Zhang X. Toxicity of tigecycline on the freshwater microalga Scenedesmus obliquus: Photosynthetic and transcriptional responses. CHEMOSPHERE 2024; 349:140885. [PMID: 38061560 DOI: 10.1016/j.chemosphere.2023.140885] [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: 08/22/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/17/2023]
Abstract
Tigecycline (TGC) is a new tetracycline antibiotic medication against multidrug-resistant bacteria. However, the toxicity of TGC to microalgae remains largely unknown. In this study, the toxicity of TGC on Scenedesmus obliquus was examined, focusing on changes in algal growth, photosynthetic activity, and transcriptome. According to an acute toxicity test, the IC10 and IC50 values were 0.72 mg/L and 4.15 mg/L, respectively. Analyses of photosynthetic efficiency and related parameters, such as light absorption, energy capture, and electron transport, identified a 35% perturbation in the IC50 group, while the IC10 group remained largely unaffected. Transcriptomic analysis showed that in the IC10 and IC50 treatment groups, there were 874 differentially expressed genes (DEGs) (220 upregulated and 654 downregulated) and 4289 DEGs (2660 upregulated and 1629 downregulated), respectively. Gene Ontology enrichment analysis showed that TGC treatment markedly affected photosynthesis, electron transport, and chloroplast functions. In the IC50 group, a clear upregulation of genes related to photosynthesis and chloroplast functions was observed, which could be an adaptive stress response. In the IC10 group, significant downregulation of DEGs involved in ribosomal pathways and peptide biosynthesis processes was observed. Kyoto Encyclopedia of Gene and Genomes enrichment analysis showed that treatment with TGC also disrupted energy production, protein synthesis, and metabolic processes in S. obliquus. Significant downregulation of key proteins related to Photosystem II was observed under the IC10 TGC treatment. Conversely, IC50 TGC treatment resulted in substantial upregulation across a broad array of photosystem-related proteins from both Photosystems II and I. IC10 and IC50 TGC treatments differentially influenced proteins involved in the photosynthetic electron transport process. This study emphasizes the potential risks of TGC pollution to microalgae, which contributes to a better understanding of the effects of antibiotic contamination in aquatic ecosystems.
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Affiliation(s)
- Liyan Wang
- Affiliated Hospital of Jiaxing University, Jiaxing 314001, China
| | - Maoxian Yang
- Affiliated Hospital of Jiaxing University, Jiaxing 314001, China
| | - Canyang Guo
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing 314001, China
| | - Yeqiu Jiang
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing 314001, China
| | - Zhihong Zhu
- Affiliated Hospital of Jiaxing University, Jiaxing 314001, China
| | - Changwei Hu
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing 314001, China.
| | - Xiaoping Zhang
- Affiliated Hospital of Jiaxing University, Jiaxing 314001, China.
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Kapuścińska D, Narajczyk M, Liakh I, Wielgomas B, Aksmann A. Nabumetone and flufenamic acid pose a serious risk to aquatic plants: A study with Chlamydomonas reinhardtii as a model organism. CHEMOSPHERE 2024; 349:140853. [PMID: 38052310 DOI: 10.1016/j.chemosphere.2023.140853] [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: 06/02/2023] [Revised: 09/25/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023]
Abstract
The aquatic environment is constantly under threat due to the release of numerous pollutants. Among them, pharmaceuticals constitute a huge and diverse group. Non-steroidal anti-inflammatory drugs (NSAIDs) are increasingly found in water bodies, but knowledge about their potential toxicity is still low. In particular, there is a lack of information about their influences on aquatic plants and algae. We estimated the susceptibility of the microalgae Chlamydomonas reinhardtii to nabumetone (NBT) and flufenamic acid (FFA), focusing on photosynthesis. Due to the differences in the structures of these compounds, it was assumed that these drugs would have different toxicities to the tested green algae. The hypothesis was confirmed by determining the effective concentration values, the intensity of photosynthesis, the intensity of dark respiration, the contents of photosynthetic pigments, the fluorescence of chlorophyll a in vivo (OJIP test), and cell ultrastructure analysis. Assessment of the toxicity of the NSAIDs was extended by the calculation of an integrated biomarker response index (IBR), which is a valuable tool in ecotoxicological studies. The obtained results indicate an over six times higher toxicity of NBT compared to FFA. After analysis of the chlorophyll a fluorescence in vivo, it was found that NBT inhibited electron transport beyond the PS II. FFA, unlike NBT, lowered the intensity of photosynthesis, probably transforming some reaction centers into "silent centers", which dissipate energy as heat. The IBR estimated based on photosynthetic parameters suggests that the toxic effect of FFA results mainly from photosynthesis disruption, whereas NBT significantly affects other cellular processes. No significant alteration in the ultrastructure of treated cells could be seen, except for changes in starch grain number and autophagic vacuoles that appeared in FFA-treated cells. To the best of our knowledge, this is the first work reporting the toxic effects of NBT and FFA on unicellular green algae.
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Affiliation(s)
- Dominika Kapuścińska
- Department of Plant Experimental Biology and Biotechnology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
| | - Magdalena Narajczyk
- Laboratory of Electron Microscopy, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland.
| | - Ivan Liakh
- Department of Toxicology, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416, Gdańsk, Poland.
| | - Bartosz Wielgomas
- Department of Toxicology, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416, Gdańsk, Poland.
| | - Anna Aksmann
- Department of Plant Experimental Biology and Biotechnology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
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3
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Liu P, Zhou J, Hong Y, Xie X. Electric-field enhanced microalgae inactivation using a flow-through copper ionization cell. JOURNAL OF HAZARDOUS MATERIALS 2020; 400:123320. [PMID: 32947717 DOI: 10.1016/j.jhazmat.2020.123320] [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: 05/06/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Using copper (Cu) to treat algal blooms is a commonly accepted method worldwide. However, the release of Cu may cause environmental and health risk. It is required to exploit an efficient way to reduce the Cu concentration but improve the algicidal effectiveness. Here, a Cu ionization cell (CIC) was designed and utilized in a flow-through system for inactivation of two bloom-forming microalgae species, Chlorella vulgaris and Microcystis aeruginosa. The results showed that the in-situ Cu release in the CIC treatment cause efficient microalgae inactivation. The 96 h-growth inhibition for C. vulgaris and M. aeruginosa reached 98.5 ± 3.1 % and 75.9 ± 2.0 % at a flow rate of 5 mL/min with the effluent Cu concentration of 554 ± 9 μg/L and 613 ± 17 μg/L, respectively. The maximum quantum yield (Fv/Fm) inhibitions of C. vulgaris and M. aeruginosa were 37.0 ± 1.6 % and 70.9 ± 2.1 %. The electric field enhanced CIC treatment has a locally higher Cu level because of the in-situ release. The CIC improved the microalgae inactivation performance by increasing the microalgae cell membrane permeability with excessive Cu uptake. The energy consumption was only 16.8 J/L. The in-situ Cu treatment in this work provides a microalgae inactivation method with the more environment-friendly and cost-effective prospect.
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Affiliation(s)
- Peirui Liu
- Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, 100083, PR China; School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, United States
| | - Jianfeng Zhou
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, United States
| | - Yu Hong
- Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, 100083, PR China.
| | - Xing Xie
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, United States.
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Ford MM, Smythers AL, McConnell EW, Lowery SC, Kolling DRJ, Hicks LM. Inhibition of TOR in Chlamydomonas reinhardtii Leads to Rapid Cysteine Oxidation Reflecting Sustained Physiological Changes. Cells 2019; 8:cells8101171. [PMID: 31569396 PMCID: PMC6829209 DOI: 10.3390/cells8101171] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/16/2019] [Accepted: 09/26/2019] [Indexed: 12/16/2022] Open
Abstract
The target of rapamycin (TOR) kinase is a master metabolic regulator with roles in nutritional sensing, protein translation, and autophagy. In Chlamydomonas reinhardtii, a unicellular green alga, TOR has been linked to the regulation of increased triacylglycerol (TAG) accumulation, suggesting that TOR or a downstream target(s) is responsible for the elusive “lipid switch” in control of increasing TAG accumulation under nutrient limitation. However, while TOR has been well characterized in mammalian systems, it is still poorly understood in photosynthetic systems, and little work has been done to show the role of oxidative signaling in TOR regulation. In this study, the TOR inhibitor AZD8055 was used to relate reversible thiol oxidation to the physiological changes seen under TOR inhibition, including increased TAG content. Using oxidized cysteine resin-assisted capture enrichment coupled with label-free quantitative proteomics, 401 proteins were determined to have significant changes in oxidation following TOR inhibition. These oxidative changes mirrored characterized physiological modifications, supporting the role of reversible thiol oxidation in TOR regulation of TAG production, protein translation, carbohydrate catabolism, and photosynthesis through the use of reversible thiol oxidation. The delineation of redox-controlled proteins under TOR inhibition provides a framework for further characterization of the TOR pathway in photosynthetic eukaryotes.
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Affiliation(s)
- Megan M Ford
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Amanda L Smythers
- Department of Chemistry, Marshall University, Huntington, WV 25755, USA.
| | - Evan W McConnell
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Sarah C Lowery
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | | | - Leslie M Hicks
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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5
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Antal T, Konyukhov I, Volgusheva A, Plyusnina T, Khruschev S, Kukarskikh G, Goryachev S, Rubin A. Chlorophyll fluorescence induction and relaxation system for the continuous monitoring of photosynthetic capacity in photobioreactors. PHYSIOLOGIA PLANTARUM 2019; 165:476-486. [PMID: 29345315 DOI: 10.1111/ppl.12693] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/08/2018] [Accepted: 01/10/2018] [Indexed: 06/07/2023]
Abstract
The development of high-performance photobioreactors equipped with automatic systems for non-invasive real-time monitoring of cultivation conditions and photosynthetic parameters is a challenge in algae biotechnology. Therefore, we developed a chlorophyll (Chl) fluorescence measuring system for the online recording of the light-induced fluorescence rise and the dark relaxation of the flash-induced fluorescence yield (Qa- - re-oxidation kinetics) in photobioreactors. This system provides automatic measurements in a broad range of Chl concentrations at high frequency of gas-tight sampling, and advanced data analysis. The performance of this new technique was tested on the green microalgae Chlamydomonas reinhardtii subjected to a sulfur deficiency stress and to long-term dark anaerobic conditions. More than thousand fluorescence kinetic curves were recorded and analyzed during aerobic and anaerobic stages of incubation. Lifetime and amplitude values of kinetic components were determined, and their dynamics plotted on heatmaps. Out of these data, stress-sensitive kinetic parameters were specified. This implemented apparatus can therefore be useful for the continuous real-time monitoring of algal photosynthesis in photobioreactors.
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Affiliation(s)
- Taras Antal
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ivan Konyukhov
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Alena Volgusheva
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Tatyana Plyusnina
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Sergei Khruschev
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Galina Kukarskikh
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Sergey Goryachev
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Andrey Rubin
- Faculty of Biology, Department of Biophysics, Lomonosov Moscow State University, Moscow 119991, Russia
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6
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Zobnina V, Lambreva MD, Rea G, Campi G, Antonacci A, Scognamiglio V, Giardi MT, Polticelli F. The plastoquinol-plastoquinone exchange mechanism in photosystem II: insight from molecular dynamics simulations. PHOTOSYNTHESIS RESEARCH 2017; 131:15-30. [PMID: 27376842 DOI: 10.1007/s11120-016-0292-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/22/2016] [Indexed: 05/23/2023]
Abstract
In the photosystem II (PSII) of oxygenic photosynthetic organisms, the reaction center (RC) core mediates the light-induced electron transfer leading to water splitting and production of reduced plastoquinone molecules. The reduction of plastoquinone to plastoquinol lowers PSII affinity for the latter and leads to its release. However, little is known about the role of protein dynamics in this process. Here, molecular dynamics simulations of the complete PSII complex embedded in a lipid bilayer have been used to investigate the plastoquinol release mechanism. A distinct dynamic behavior of PSII in the presence of plastoquinol is observed which, coupled to changes in charge distribution and electrostatic interactions, causes disruption of the interactions seen in the PSII-plastoquinone complex and leads to the "squeezing out" of plastoquinol from the binding pocket. Displacement of plastoquinol closes the second water channel, recently described in a 2.9 Å resolution PSII structure (Guskov et al. in Nat Struct Mol Biol 16:334-342, 2009), allowing to rule out the proposed "alternating" mechanism of plastoquinol-plastoquinone exchange, while giving support to the "single-channel" one. The performed simulations indicated a pivotal role of D1-Ser264 in modulating the dynamics of the plastoquinone binding pocket and plastoquinol-plastoquinone exchange via its interaction with D1-His252 residue. The effects of the disruption of this hydrogen bond network on the PSII redox reactions were experimentally assessed in the D1 site-directed mutant Ser264Lys.
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Affiliation(s)
- Veranika Zobnina
- Theoretical Biology and Bioinformatics Laboratory, Department of Sciences, Roma Tre University, Viale G. Marconi 446, 00146, Rome, Italy
| | - Maya D Lambreva
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | - Giuseppina Rea
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | - Gaetano Campi
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | - Amina Antonacci
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | | | | | - Fabio Polticelli
- Theoretical Biology and Bioinformatics Laboratory, Department of Sciences, Roma Tre University, Viale G. Marconi 446, 00146, Rome, Italy.
- National Institute of Nuclear Physics, Roma Tre Section, 00146, Rome, Italy.
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7
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Maslakov AS, Antal TK, Riznichenko GY, Rubin AB. Modeling of primary photosynthetic processes using the kinetic Monte Carlo method. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s000635091603009x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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8
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Plyusnina TY, Khruschev SS, Riznichenko GY, Rubin AB. An analysis of the chlorophyll fluorescence transient by spectral multi-exponential approximation. Biophysics (Nagoya-shi) 2015. [DOI: 10.1134/s000635091503015x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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9
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Vredenberg W. A simple routine for quantitative analysis of light and dark kinetics of photochemical and non-photochemical quenching of chlorophyll fluorescence in intact leaves. PHOTOSYNTHESIS RESEARCH 2015; 124:87-106. [PMID: 25739901 PMCID: PMC4368846 DOI: 10.1007/s11120-015-0097-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/10/2015] [Indexed: 05/09/2023]
Abstract
Paper describes principles and application of a novel routine that enables the quantitative analysis of the photochemical O-J phase of the variable fluorescence F v associated with the reversible photo-reduction of the secondary electron acceptor QA of photosystem II (PSII) in algae and intact leaves. The kinetic parameters that determine the variable fluorescence F (PP)(t) associated with the release of photochemical quenching are estimated from 10 µs time-resolved light-on and light-off responses of F v induced by two subsequent light pulses of 0.25 (default) and 1000 ms duration, respectively. Application of these pulses allows estimations of (i) the actual value of the rate constants k L and k AB of the light excitation (photoreduction of QA) and of the dark re-oxidation of photoreduced QA ([Formula: see text]), respectively, (ii) the actual maximal normalized variable fluorescence [nF v] associated with 100 % photoreduction of QA of open RCs, and (iii) the actual size β of RCs in which the re-oxidation of [Formula: see text] is largely suppressed (QB-nonreducing RC with k AB ~ 0). The rate constants of the dark reversion of Fv associated with the release of photo-electrochemical quenching F (PE) and photo-electric stimulation F (CET) in the successive J-I and I-P parts of the thermal phase are in the range of (100 ms)(-1) and (1 s)(-1), respectively. The kinetics of fluorescence changes during and after the I-P phase are given special attention in relation to the hypothesis on the involvement of a Δµ H+-dependent effect during this phase and thereafter. Paper closes with author's personal view on the demands that should be fulfilled for chlorophyll fluorescence methods being a correct and unchallenged signature of photosynthesis in algae and plants.
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Affiliation(s)
- Wim Vredenberg
- Department of Plant Physiology, Wageningen University and Research, Wageningen, The Netherlands,
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Stirbet A, Riznichenko GY, Rubin AB, Govindjee. Modeling chlorophyll a fluorescence transient: relation to photosynthesis. BIOCHEMISTRY (MOSCOW) 2015; 79:291-323. [PMID: 24910205 DOI: 10.1134/s0006297914040014] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To honor Academician Alexander Abramovitch Krasnovsky, we present here an educational review on the relation of chlorophyll a fluorescence transient to various processes in photosynthesis. The initial event in oxygenic photosynthesis is light absorption by chlorophylls (Chls), carotenoids, and, in some cases, phycobilins; these pigments form the antenna. Most of the energy is transferred to reaction centers where it is used for charge separation. The small part of energy that is not used in photochemistry is dissipated as heat or re-emitted as fluorescence. When a photosynthetic sample is transferred from dark to light, Chl a fluorescence (ChlF) intensity shows characteristic changes in time called fluorescence transient, the OJIPSMT transient, where O (the origin) is for the first measured minimum fluorescence level; J and I for intermediate inflections; P for peak; S for semi-steady state level; M for maximum; and T for terminal steady state level. This transient is a real signature of photosynthesis, since diverse events can be related to it, such as: changes in redox states of components of the linear electron transport flow, involvement of alternative electron routes, the build-up of a transmembrane pH gradient and membrane potential, activation of different nonphotochemical quenching processes, activation of the Calvin-Benson cycle, and other processes. In this review, we present our views on how different segments of the OJIPSMT transient are influenced by various photosynthetic processes, and discuss a number of studies involving mathematical modeling and simulation of the ChlF transient. A special emphasis is given to the slower PSMT phase, for which many studies have been recently published, but they are less known than on the faster OJIP phase.
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Affiliation(s)
- A Stirbet
- 204 Anne Burras Lane, Newport News, VA 23606, USA.
| | | | | | - Govindjee
- Department of Plant Biology, Department of Biochemistry and Center of Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Zhang P, Frankel LK, Bricker TM. Integration of apo-α-phycocyanin into phycobilisomes and its association with FNRL in the absence of the phycocyanin α-subunit lyase (CpcF) in Synechocystis sp. PCC 6803. PLoS One 2014; 9:e105952. [PMID: 25153076 PMCID: PMC4143364 DOI: 10.1371/journal.pone.0105952] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/29/2014] [Indexed: 12/27/2022] Open
Abstract
Phycocyanin is an important component of the phycobilisome, which is the principal light-harvesting complex in cyanobacteria. The covalent attachment of the phycocyanobilin chromophore to phycocyanin is catalyzed by the enzyme phycocyanin lyase. The photosynthetic properties and phycobilisome assembly state were characterized in wild type and two mutants which lack holo-α-phycocyanin. Insertional inactivation of the phycocyanin α-subunit lyase (ΔcpcF mutant) prevents the ligation of phycocyanobilin to α-phycocyanin (CpcA), while disruption of the cpcB/A/C2/C1 operon in the CK mutant prevents synthesis of both apo-α-phycocyanin (apo-CpcA) and apo-β-phycocyanin (apo-CpcB). Both mutants exhibited similar light saturation curves under white actinic light illumination conditions, indicating the phycobilisomes in the ΔcpcF mutant are not fully functional in excitation energy transfer. Under red actinic light illumination, wild type and both phycocyanin mutant strains exhibited similar light saturation characteristics. This indicates that all three strains contain functional allophycocyanin cores associated with their phycobilisomes. Analysis of the phycobilisome content of these strains indicated that, as expected, wild type exhibited normal phycobilisome assembly and the CK mutant assembled only the allophycocyanin core. However, the ΔcpcF mutant assembled phycobilisomes which, while much larger than the allophycocyanin core observed in the CK mutant, were significantly smaller than phycobilisomes observed in wild type. Interestingly, the phycobilisomes from the ΔcpcF mutant contained holo-CpcB and apo-CpcA. Additionally, we found that the large form of FNR (FNRL) accumulated to normal levels in wild type and the ΔcpcF mutant. In the CK mutant, however, significantly less FNRL accumulated. FNRL has been reported to associate with the phycocyanin rods in phycobilisomes via its N-terminal domain, which shares sequence homology with a phycocyanin linker polypeptide. We suggest that the assembly of apo-CpcA in the phycobilisomes of ΔcpcF can stabilize FNRL and modulate its function. These phycobilisomes, however, inefficiently transfer excitation energy to Photosystem II.
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Affiliation(s)
- Pengpeng Zhang
- Department of Biological Sciences, Biochemistry and Molecular Biology Division, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Laurie K. Frankel
- Department of Biological Sciences, Biochemistry and Molecular Biology Division, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Terry M. Bricker
- Department of Biological Sciences, Biochemistry and Molecular Biology Division, Louisiana State University, Baton Rouge, Louisiana, United States of America
- * E-mail:
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12
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Stirbet A. Chlorophyll a fluorescence induction: a personal perspective of the thermal phase, the J-I-P rise. PHOTOSYNTHESIS RESEARCH 2012; 113:15-61. [PMID: 22810945 DOI: 10.1007/s11120-012-9754-5] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 05/29/2012] [Indexed: 05/03/2023]
Abstract
The fast (up to 1 s) chlorophyll (Chl) a fluorescence induction (FI) curve, measured under saturating continuous light, has a photochemical phase, the O-J rise, related mainly to the reduction of Q(A), the primary electron acceptor plastoquinone of Photosystem II (PSII); here, the fluorescence rise depends strongly on the number of photons absorbed. This is followed by a thermal phase, the J-I-P rise, which disappears at subfreezing temperatures. According to the mainstream interpretation of the fast FI, the variable fluorescence originates from PSII antenna, and the oxidized Q(A) is the most important quencher influencing the O-J-I-P curve. As the reaction centers of PSII are gradually closed by the photochemical reduction of Q(A), Chl fluorescence, F, rises from the O level (the minimal level) to the P level (the peak); yet, the relationship between F and [Q(A) (-)] is not linear, due to the presence of other quenchers and modifiers. Several alternative theories have been proposed, which give different interpretations of the O-J-I-P transient. The main idea in these alternative theories is that in saturating light, Q(A) is almost completely reduced already at the end of the photochemical phase O-J, but the fluorescence yield is lower than its maximum value due to the presence of either a second quencher besides Q(A), or there is an another process quenching the fluorescence; in the second quencher hypothesis, this quencher is consumed (or the process of quenching the fluorescence is reversed) during the thermal phase J-I-P. In this review, we discuss these theories. Based on our critical examination, that includes pros and cons of each theory, as well mathematical modeling, we conclude that the mainstream interpretation of the O-J-I-P transient is the most credible one, as none of the alternative ideas provide adequate explanation or experimental proof for the almost complete reduction of Q(A) at the end of the O-J phase, and for the origin of the fluorescence rise during the thermal phase. However, we suggest that some of the factors influencing the fluorescence yield that have been proposed in these newer theories, as e.g., the membrane potential ΔΨ, as suggested by Vredenberg and his associates, can potentially contribute to modulate the O-J-I-P transient in parallel with the reduction of Q(A), through changes at the PSII antenna and/or at the reaction center, or, possibly, through the control of the oxidation-reduction of the PQ-pool, including proton transfer into the lumen, as suggested by Rubin and his associates. We present in this review our personal perspective mainly on our understanding of the thermal phase, the J-I-P rise during Chl a FI in plants and algae.
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Jena S, Acharya S, Mohapatra PK. Variation in effects of four OP insecticides on photosynthetic pigment fluorescence of Chlorella vulgaris Beij. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 80:111-117. [PMID: 22440131 DOI: 10.1016/j.ecoenv.2012.02.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 02/13/2012] [Accepted: 02/18/2012] [Indexed: 05/31/2023]
Abstract
Effects of the insecticides quinalphos, chlorfenvinphos, dimethoate and phorate on photosystem activity of Chlorella vulgaris were investigated by different chlorophyll fluorescence measurements. Exposure to each of the insecticides increased the proportion of inactivated PS II reaction center. Quinalphos and chlorfenvinphos caused OJIP fluorescence reduction at all levels by decreasing the proportion of Q(A)-reducing PS II reaction centers (RCs). The other two insecticides affected OJIP fluorescence rise by hindering the electron transport beyond Q(A). Insecticide treatment resulted in decrease of the density of active RC and performance indices (PI) by enhanced dissipated energy flux per active RC. Antenna size was severely minimized by quinalphos and chlorfenvinphos treatment whereas other two insecticides had no such effect. Each insecticide treatment caused increase of photosystem antenna/core and PS II/PS I fluorescence ratios. Quinalphos and chlorfenvinphos affected the donor sides of photosystems whereas dimethoate and phorate inhibited electron transfer beyond Q(A) (acceptor side).
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Affiliation(s)
- Sridevi Jena
- P.G. Department of Botany, Utkal University, Bhubaneswar 751004, India
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14
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Roose JL, Frankel LK, Bricker TM. Developmental defects in mutants of the PsbP domain protein 5 in Arabidopsis thaliana. PLoS One 2011; 6:e28624. [PMID: 22174848 PMCID: PMC3235149 DOI: 10.1371/journal.pone.0028624] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 11/11/2011] [Indexed: 11/25/2022] Open
Abstract
Plants contain an extensive family of PsbP-related proteins termed PsbP-like (PPL) and PsbP domain (PPD) proteins, which are localized to the thylakoid lumen. The founding member of this family, PsbP, is an established component of the Photosystem II (PS II) enzyme, and the PPL proteins have also been functionally linked to other photosynthetic processes. However, the functions of the remaining seven PPD proteins are unknown. To elucidate the function of the PPD5 protein (At5g11450) in Arabidopsis, we have characterized a mutant T-DNA insertion line (SALK_061118) as well as several RNAi lines designed to suppress the expression of this gene. The functions of the photosynthetic electron transfer reactions are largely unaltered in the ppd5 mutants, except for a modest though significant decrease in NADPH dehydrogenase (NDH) activity. Interestingly, these mutants show striking plant developmental and morphological defects. Relative to the wild-type Col-0 plants, the ppd5 mutants exhibit both increased lateral root branching and defects associated with axillary bud formation. These defects include the formation of additional rosettes originating from axils at the base of the plant as well as aerial rosettes formed at the axils of the first few nodes of the shoot. The root-branching phenotype is chemically complemented by treatment with the synthetic strigolactone, GR24. We propose that the developmental defects observed in the ppd5 mutants are related to a deficiency in strigolactone biosynthesis.
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Affiliation(s)
- Johnna L Roose
- Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, Louisiana, United States of America.
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Lelong A, Haberkorn H, Le Goïc N, Hégaret H, Soudant P. A new insight into allelopathic effects of Alexandrium minutum on photosynthesis and respiration of the diatom Chaetoceros neogracile revealed by photosynthetic-performance analysis and flow cytometry. MICROBIAL ECOLOGY 2011; 62:919-930. [PMID: 21728039 DOI: 10.1007/s00248-011-9889-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 06/06/2011] [Indexed: 05/31/2023]
Abstract
The allelopathic effects of Alexandrium minutum, a toxic dinoflagellate, on the diatom Chaetoceros neogracile were evaluated using unialgal cultures evaluated by flow cytometry (FCM) and photosynthetic-performance analysis. Using FCM, we demonstrated that red chlorophyll fluorescence, relative cell size (Forward scatter of blue laser light, FSC) and cell complexity (Side scatter, 90°-angle scatter of blue laser light, SSC) significantly and rapidly decreased in C. neogracile cells exposed to A. minutum. Cells of C. neogracile exposed to A. minutum had fewer active photosynthetic reaction centers and sharply decreased photosynthetic efficiency. These effects were intensified with advancing A. minutum batch culture age and cell density. The supernatant of A. minutum contained the majority of the putative allelopathic compounds, and the biological activity of these compounds remained active less than 9 h after release. This paper describes for the first time specific effects of allelochemicals produced by A. minutum on the photosynthetic apparatus of microalgal target cells. The biochemical composition of A. minutum allelopathic agents, however, remains unknown and still needs to be investigated.
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Affiliation(s)
- Aurélie Lelong
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR6539, Institut Universitaire Européen de la Mer (IUEM), Place Nicolas Copernic, 29280 Plouzané, France
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Buonasera K, Lambreva M, Rea G, Touloupakis E, Giardi MT. Technological applications of chlorophyll a fluorescence for the assessment of environmental pollutants. Anal Bioanal Chem 2011; 401:1139-51. [DOI: 10.1007/s00216-011-5166-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 05/31/2011] [Accepted: 06/02/2011] [Indexed: 12/31/2022]
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17
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Membrane potential is involved in regulation of photosynthetic reactions in the marine diatom Thalassiosira weissflogii. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2010; 102:169-73. [PMID: 21131210 DOI: 10.1016/j.jphotobiol.2010.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 11/10/2010] [Accepted: 11/11/2010] [Indexed: 10/18/2022]
Abstract
High-intensity Chl fluorescence transients (OJIP transients) and light-induced kinetics of the delayed light emission were measured in diatom microalga Thalassiosira weissflogii in the presence of various uncouplers and photosynthetic inhibitors. The I step in the OJIP transients in T. weissflogii was essentially reduced or completely absent but was restored in the presence of uncouplers valinomycin, FCCP, and nigericin. Moreover, valinomycin enhanced ΔpH-dependent non-photochemical fluorescence quenching following the OJIP rise. In the presence of valinomycin, the transthylakoid membrane potential was significantly inhibited as evaluated by measurements of the delayed light emission. The results suggest a membrane potential control of the fluorescence yield in T. weissflogii. Possible mechanisms underlying the observed effects of uncouplers are discussed.
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Zhang S, Frankel LK, Bricker TM. The Sll0606 protein is required for photosystem II assembly/stability in the cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 2010; 285:32047-54. [PMID: 20724474 DOI: 10.1074/jbc.m110.166983] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An insertional transposon mutation in the sll0606 gene was found to lead to a loss of photoautotrophy but not photoheterotrophy in the cyanobacterium Synechocystis sp. PCC 6803. Complementation analysis of this mutant (Tsll0606) indicated that an intact sll0606 gene could fully restore photoautotrophic growth. Gene organization in the vicinity of sll0606 indicates that it is not contained in an operon. No electron transport activity was detected in Tsll0606 using water as an electron donor and 2,6-dichlorobenzoquinone as an electron acceptor, indicating that Photosystem II (PS II) was defective. Electron transport activity using dichlorophenol indolephenol plus ascorbate as an electron donor to methyl viologen, however, was the same as observed in the control strain. This indicated that electron flow through Photosystem I was normal. Fluorescence induction and decay parameters verified that Photosystem II was highly compromised. The quantum yield for energy trapping by Photosystem II (F(V)/F(M)) in the mutant was less than 10% of that observed in the control strain. The small variable fluorescence yield observed after a single saturating flash exhibited aberrant Q(A)(-) reoxidation kinetics that were insensitive to dichloromethylurea. Immunological analysis indicated that whereas the D2 and CP47 proteins were modestly affected, the D1 and CP43 components were dramatically reduced. Analysis of two-dimensional blue native/lithium dodecyl sulfate-polyacrylamide gels indicated that no intact PS II monomer or dimers were observed in the mutant. The CP43-less PS II monomer did accumulate to detectable levels. Our results indicate that the Sll0606 protein is required for the assembly/stability of a functionally competent Photosystem II.
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Affiliation(s)
- Shulu Zhang
- Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Mohapatra PK, Khillar R, Hansdah B, Mohanty RC. Photosynthetic and fluorescence responses of Solanum melangena L. to field application of dimethoate. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2010; 73:78-83. [PMID: 19796815 DOI: 10.1016/j.ecoenv.2009.08.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2008] [Revised: 04/30/2009] [Accepted: 08/29/2009] [Indexed: 05/28/2023]
Abstract
The organophosphorus insecticide dimethoate, at field concentration (1.419+/-0.086mga.i.g(-1)fr.wt. of leaf tissue) did not cause any significant degradation of chlorophylls and carotenoids in Solanum melangena L. On the other hand, there was significant reduction of photosynthesis, transpiration and stomatal conductance during 6h after spray application of the insecticide. Distinct change of OJIP fluorescence transient with increase of J and I rise and corresponding decrease in P rise was observed during 6h after insecticide application. The fluorescence parameters, viz., relative variable fluorescence at J level (V(j)), net rate of PS II closure (M(0)), energy dissipation (DI(0)/RC) and maximum trapping rate of active PS II (TR(0)/RC), during the same treatment period, showed significant increase but variable fluorescence (F(v)), fluorescence yield (TR(0)/Abs), electron transport probability (ET(0)/TR(0)), and activity of RC (ET(0)/RC) showed significant decrease. All physiological and fluorescence parameters, and the OJIP fluorescence transient recovered steadily to the control level during 48h after insecticide application. There was continuous reduction in the insecticide content of the leaf tissue during the observation period.
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Affiliation(s)
- P K Mohapatra
- Post Graduate Department of Botany, Utkal University, Bhubaneswar 751 004, India.
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Antal TK, Graevskaya EE, Matorin DN, Volgusheva AA, Osipov VA, Krendeleva TE, Rubin AB. Assessment of the effects of methylmercury and copper ions on primary processes of photosynthesis in green microalga Chlamydomonas moewusii by analysis of the kinetic curves of variable chlorophyll fluorescence. Biophysics (Nagoya-shi) 2009. [DOI: 10.1134/s0006350909040149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Antal TK, Matorin DN, Ilyash LV, Volgusheva AA, Osipov V, Konyuhov IV, Krendeleva TE, Rubin AB. Probing of photosynthetic reactions in four phytoplanktonic algae with a PEA fluorometer. PHOTOSYNTHESIS RESEARCH 2009; 102:67-76. [PMID: 19731073 DOI: 10.1007/s11120-009-9491-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2009] [Accepted: 08/17/2009] [Indexed: 05/24/2023]
Abstract
High-resolution light-induced kinetics of chlorophyll fluorescence (OJIP transients) were recorded and analyzed in cultures of diatoms (Thalassiosira weissflogii, Chaetoceros mulleri) and dinoflagellates (Amphidinium carterae, Prorocentrum minimum). Fluorescence transients showed the rapid exponential initial rise from the point O indicating low connectivity between PS II units and high absorption cross-section of PS II antenna. Dark-adapted dinoflagellates revealed capability to maintain the PS I-mediated re-oxidation of the PQ pool at the exposure to strong actinic light that may lead to the underestimation of F(M) value. In OJIP transients recorded in phytoplanktonic algae the fluorescence yield at the point O exceeded F(O) level because Q(A) has been already partly reduced at 50 micros after the illumination onset. PEA was also employed to study the recovery of photosynthetic reactions in T. weissflogii during incubation of nitrogen starved cells in N-replete medium. N limitation caused the impairment of electron transport between Q(A) and PQs, accumulation of closed PS II centers, and the reduced ability to generate transmembrane DeltapH upon illumination, almost fully restored during the recovery period. The recovered cells showed much higher values of NPQ than control ones suggesting maximization of photoprotection mechanisms in the population with a 'stress history.'
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Affiliation(s)
- T K Antal
- Faculty of Biology, Moscow State University, Moscow, Russia.
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Characterization and complementation of a psbR mutant in Arabidopsis thaliana. Arch Biochem Biophys 2009; 489:34-40. [DOI: 10.1016/j.abb.2009.07.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 07/20/2009] [Accepted: 07/22/2009] [Indexed: 11/22/2022]
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Liu H, Frankel LK, Bricker TM. Functional complementation of the Arabidopsis thaliana psbo1 mutant phenotype with an N-terminally His6-tagged PsbO-1 protein in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1029-38. [PMID: 19289096 DOI: 10.1016/j.bbabio.2009.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/03/2009] [Accepted: 03/06/2009] [Indexed: 10/21/2022]
Abstract
The Arabidopsis thaliana mutant psbo1 has recently been described and characterized. Loss of expression of the PsbO-1 protein leads to a variety of functional perturbations including elevated levels of the PsbO-2 protein and defects on both the oxidizing- and reducing-sides of Photosystem II. In this communication, two plant lines were produced using the psbo1 mutant as transgenic host, which contained an N-terminally histidine(6)-tagged PsbO-1 protein. This protein was expressed and correctly targeted into the thylakoid lumen. Immunological analysis indicated that different levels of expression of the modified PsbO-1 protein were obtained in different transgenic plant lines and that the level of expression in each line was stable over several generations. Examination of the Photosystem II closure kinetics demonstrated that the defective double reduction of Q(B) and the delayed exchange of Q(B)H(2) with the plastoquinone pool which were observed during the characterization of the psbo1 mutant were effectively restored to wild-type levels by the His(6)-tagged PsbO-1 protein. Flash fluorescence induction and decay were also examined. Our results indicated that high expression of the modified PsbO-1 was required to increase the ratio of PS II(alpha)/PS II(beta) reaction centers to wild-type levels. Fluorescence decay kinetics in the absence of DCMU indicated that the expression of the His(6)-tagged PsbO-1 protein restored efficient electron transfer to Q(B), while in the presence of DCMU, charge recombination between Q(A)(-) and the S(2) state of the oxygen-evolving complex occurred at near wild-type rates. Our results indicate that high expression of the His(6)-tagged PsbO-1 protein efficiently complements nearly all of the photochemical defects observed in the psbo1 mutant. Additionally, this study establishes a platform on which the in vivo consequences of site-directed mutagenesis of the PsbO-1 protein can be examined.
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Affiliation(s)
- Haijun Liu
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, LA 70803, USA
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Lazár D, Schansker G. Models of Chlorophyll a Fluorescence Transients. PHOTOSYNTHESIS IN SILICO 2009. [DOI: 10.1007/978-1-4020-9237-4_5] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Modeling of Chlorophyll a Fluorescence Kinetics in Plant Cells: Derivation of a Descriptive Algorithm. PHOTOSYNTHESIS IN SILICO 2009. [DOI: 10.1007/978-1-4020-9237-4_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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