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Bag P, Shutova T, Shevela D, Lihavainen J, Nanda S, Ivanov AG, Messinger J, Jansson S. Flavodiiron-mediated O 2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring. Nat Commun 2023; 14:3210. [PMID: 37270605 DOI: 10.1038/s41467-023-38938-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/23/2023] [Indexed: 06/05/2023] Open
Abstract
Green organisms evolve oxygen (O2) via photosynthesis and consume it by respiration. Generally, net O2 consumption only becomes dominant when photosynthesis is suppressed at night. Here, we show that green thylakoid membranes of Scots pine (Pinus sylvestris L) and Norway spruce (Picea abies) needles display strong O2 consumption even in the presence of light when extremely low temperatures coincide with high solar irradiation during early spring (ES). By employing different electron transport chain inhibitors, we show that this unusual light-induced O2 consumption occurs around photosystem (PS) I and correlates with higher abundance of flavodiiron (Flv) A protein in ES thylakoids. With P700 absorption changes, we demonstrate that electron scavenging from the acceptor-side of PSI via O2 photoreduction is a major alternative pathway in ES. This photoprotection mechanism in vascular plants indicates that conifers have developed an adaptative evolution trajectory for growing in harsh environments.
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Affiliation(s)
- Pushan Bag
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford, UK
| | - Tatyana Shutova
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå, Sweden
| | - Jenna Lihavainen
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Sanchali Nanda
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, London, ON, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå, Sweden
- Department of Chemistry-Ångström laboratory, Uppsala University, Uppsala, Sweden
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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Popova AV, Stefanov M, Ivanov AG, Velitchkova M. The Role of Alternative Electron Pathways for Effectiveness of Photosynthetic Performance of Arabidopsis thaliana, Wt and Lut2, under Low Temperature and High Light Intensity. Plants 2022; 11:plants11172318. [PMID: 36079699 PMCID: PMC9460638 DOI: 10.3390/plants11172318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/22/2022] [Accepted: 09/01/2022] [Indexed: 12/02/2022]
Abstract
A recent investigation has suggested that the enhanced capacity for PSI-dependent cyclic electron flow (CEF) and PSI-dependent energy quenching that is related to chloroplast structural changes may explain the lower susceptibility of lut2 to combined stresses—a low temperature and a high light intensity. The possible involvement of alternative electron transport pathways, proton gradient regulator 5 (PGR5)-dependent CEF and plastid terminal oxidase (PTOX)-mediated electron transfer to oxygen in the response of Arabidopsis plants—wild type (wt) and lut2—to treatment with these two stressors was assessed by using specific electron transport inhibitors. Re-reduction kinetics of P700+ indicated that the capacity for CEF was higher in lut2 when this was compared to wt. Exposure of wt plants to the stress conditions caused increased CEF and was accompanied by a substantial raise in PGR5 and PTOX quantities. In contrast, both PGR5 and PTOX levels decreased under the same stress conditions in lut2, and inhibiting PGR5-dependent pathway by AntA did not exhibit any significant effects on CEF during the stress treatment and recovery period. Electron microscopy observations demonstrated that under control conditions the degree of grana stacking was much lower in lut2, and it almost disappeared under the combined stresses, compared to wt. The role of differential responses of alternative electron transport pathways in the acclimation to the stress conditions that are studied is discussed.
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Affiliation(s)
- Antoaneta V. Popova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
- Correspondence:
| | - Martin Stefanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
| | - Alexander G. Ivanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
- Department of Biology, University of Western Ontario, 1151 Richmond Str. N., London, ON N6A 5B7, Canada
| | - Maya Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
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3
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Szyszka-Mroz B, Ivanov AG, Trick CG, Hüner NPA. Palmelloid formation in the Antarctic psychrophile, Chlamydomonas priscuii, is photoprotective. Front Plant Sci 2022; 13:911035. [PMID: 36119589 PMCID: PMC9470844 DOI: 10.3389/fpls.2022.911035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/01/2022] [Indexed: 05/27/2023]
Abstract
Cultures of the obligate, Antarctic psychrophile, Chlamydomonas priscuii grown at permissive low temperature (8°C) are composed of flagellated, single cells, as well as non-motile, multicellular palmelloids. The relative proportions of the two cell types are temperature dependent. However, the temperature dependence for palmelloid formation is not restricted to psychrophilic C. priscuii but appears to be a general response of mesophilic Chlamydomonas species (C. reinhardtii and C. raudensis) to non-permissive growth temperatures. To examine potential differences in photosynthetic performance between single cells versus palmelloids of the psychrophile, a cell filtration technique was developed to separate single cells from palmelloids of C. priscuii grown at 8°C. Flow cytometry was used to estimate the diameter of isolated single cells (≤5 μm) versus isolated palmelloids of varying size (≥8 μm). Compared to single cells, palmelloids of C. priscuii showed a decrease in the abundance of light-harvesting complex II (LHCII) proteins with a 2-fold higher Chl a/b ratio. A decrease in both lutein and β-carotene in palmelloids resulted in carotenoid pools which were 27% lower in palmelloids compared to single cells of the psychrophile. Chlorophyll fluorescence analyses of the isolated fractions revealed that maximum photochemical efficiency of PSII (Fv/Fm) was comparable for both single cells and palmelloids of C. priscuii. However, isolated palmelloids exhibited lower excitation pressure, measured as 1 - qL, but higher yield of PSII (ΦPSII) and 50% higher rates of electron transport (ETR) than single cells exposed to high light at 8°C. This decreased sensitivity to high light in isolated palmelloids compared to single cells was associated with greater non-regulated dissipation of excess absorbed energy (ΦNO) with minimal differences in ΦNPQ in C. priscuii in response to increasing irradiance at low temperature. The ratio ΦNO/ΦNPQ observed for isolated palmelloids of C. priscuii developed at 8°C (1.414 ± 0.036) was 1.38-fold higher than ΦNO/ΦNPQ of isolated single cells (1.021 ± 0.018) exposed to low temperature combined with high light (1,000 μmol m-2 s-1). The differences in the energy quenching capacities between palmelloids and single cells are discussed in terms of enhanced photoprotection of C. priscuii palmelloids against low-temperature photoinhibition.
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Affiliation(s)
- Beth Szyszka-Mroz
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, Canada
| | - Alexander G. Ivanov
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Charles G. Trick
- School of Public Health, University of Saskatchewan, Saskatoon, SK, Canada
| | - Norman P. A. Hüner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, Canada
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Ivanov AG, Krol M, Savitch LV, Szyszka-Mroz B, Roche J, Sprott DP, Selstam E, Wilson KW, Gardiner R, Öquist G, Hurry VM, Hüner NPA. The decreased PG content of pgp1 inhibits PSI photochemistry and limits reaction center and light-harvesting polypeptide accumulation in response to cold acclimation. Planta 2022; 255:36. [PMID: 35015152 DOI: 10.1007/s00425-022-03819-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Decreased PG constrains PSI activity due to inhibition of transcript and polypeptide abundance of light-harvesting and reaction center polypeptides generating a reversible, yellow phenotype during cold acclimation of pgp1. Cold acclimation of the Arabidopsis pgp1 mutant at 5 °C resulted in a pale-yellow phenotype with abnormal chloroplast ultrastructure compared to its green phenotype upon growth at 20 °C despite a normal cold-acclimation response at the transcript level. In contrast, wild type maintained its normal green phenotype and chloroplast ultrastructure irrespective of growth temperature. In contrast to cold acclimation of WT, growth of pgp1 at 5 °C limited the accumulation of Lhcbs and Lhcas assessed by immunoblotting. However, a novel 43 kD polypeptide of Lhcb1 as well as a 29 kD polypeptide of Lhcb3 accumulated in the soluble fraction which was absent in the thylakoid membrane fraction of cold-acclimated pgp1 which was not observed in WT. Cold acclimation of pgp1 destabilized the Chl-protein complexes associated with PSI and predisposed energy distribution in favor of PSII rather than PSI compared to the WT. Functionally, in vivo PSI versus PSII photochemistry was inhibited in cold-acclimated pgp1 to a greater extent than in WT relative to controls. Greening of the pale-yellow pgp1 was induced when cold-acclimated pgp1 was shifted from 5 to 20 °C which resulted in a marked decrease in excitation pressure to a level comparable to WT. Concomitantly, Lhcbs and Lhcas accumulated with a simultaneous decrease in the novel 43 and 29kD polypeptides. We conclude that the reduced levels of phosphatidyldiacylglycerol in the pgp1 limit the capacity of the mutant to maintain the structure and function of its photosynthetic apparatus during cold acclimation. Thus, maintenance of normal thylakoid phosphatidyldiacylglycerol levels is essential to stabilize the photosynthetic apparatus during cold acclimation.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria
| | - Marianna Krol
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Leonid V Savitch
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, K1A OC6, Canada
| | - Beth Szyszka-Mroz
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Jessica Roche
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
- , 6/136 Austin St, Mt. Victoria, Wellington, 6011, New Zealand
| | - D P Sprott
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, K1A OC6, Canada
| | - Eva Selstam
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187, Umeå, Sweden
| | - Kenneth W Wilson
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Richard Gardiner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Gunnar Öquist
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187, Umeå, Sweden
| | - Vaughan M Hurry
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187, Umeå, Sweden
| | - Norman P A Hüner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada.
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Hüner NPA, Smith DR, Cvetkovska M, Zhang X, Ivanov AG, Szyszka-Mroz B, Kalra I, Morgan-Kiss R. Photosynthetic adaptation to polar life: Energy balance, photoprotection and genetic redundancy. J Plant Physiol 2022; 268:153557. [PMID: 34922115 DOI: 10.1016/j.jplph.2021.153557] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/27/2021] [Accepted: 10/24/2021] [Indexed: 06/14/2023]
Abstract
The persistent low temperature that characterize polar habitats combined with the requirement for light for all photoautotrophs creates a conundrum. The absorption of too much light at low temperature can cause an energy imbalance that decreases photosynthetic performance that has a negative impact on growth and can affect long-term survival. The goal of this review is to survey the mechanism(s) by which polar photoautotrophs maintain cellular energy balance, that is, photostasis to overcome the potential for cellular energy imbalance in their low temperature environments. Photopsychrophiles are photosynthetic organisms that are obligately adapted to low temperature (0⁰- 15 °C) but usually die at higher temperatures (≥20 °C). In contrast, photopsychrotolerant species can usually tolerate and survive a broad range of temperatures (5⁰- 40 °C). First, we summarize the basic concepts of excess excitation energy, energy balance, photoprotection and photostasis and their importance to survival in polar habitats. Second, we compare the photoprotective mechanisms that underlie photostasis and survival in aquatic cyanobacteria and green algae as well as terrestrial Antarctic and Arctic plants. We show that polar photopsychrophilic and photopsychrotolerant organisms attain energy balance at low temperature either through a regulated reduction in the efficiency of light absorption or through enhanced capacity to consume photosynthetic electrons by the induction of O2 as an alternative electron acceptor. Finally, we compare the published genomes of three photopsychrophilic and one photopsychrotolerant alga with five mesophilic green algae including the model green alga, Chlamydomonas reinhardtii. We relate our genomic analyses to photoprotective mechanisms that contribute to the potential attainment of photostasis. Finally, we discuss how the observed genomic redundancy in photopsychrophilic genomes may confer energy balance, photoprotection and resilience to their harsh polar environment. Primary production in aquatic, Antarctic and Arctic environments is dependent on diverse algal and cyanobacterial communities. Although mosses and lichens dominate the Antarctic terrestrial landscape, only two extant angiosperms exist in the Antarctic. The identification of a single 'molecular key' to unravel adaptation of photopsychrophily and photopsychrotolerance remains elusive. Since these photoautotrophs represent excellent biomarkers to assess the impact of global warming on polar ecosystems, increased study of these polar photoautotrophs remains essential.
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Affiliation(s)
- Norman P A Hüner
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
| | - David R Smith
- Dept. of Biology, University of Western Ontario, London, N6A 5B7, Canada.
| | | | - Xi Zhang
- Dept. of Biology, University of Western Ontario, London, N6A 5B7, Canada.
| | - Alexander G Ivanov
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada; Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria.
| | - Beth Szyszka-Mroz
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
| | - Isha Kalra
- Dept. of Microbiology, Miami University of Ohio, Oxford, OH, 45056, USA.
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6
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Thorn RG, Banwell A, Pham TH, Vidal NP, Manful CF, Nadeem M, Ivanov AG, Szyszka Mroz B, Bonneville MB, Hüner NPA, Piercey-Normore MD, Thomas R. Identification and analyses of the chemical composition of a naturally occurring albino mutant chanterelle. Sci Rep 2021; 11:20590. [PMID: 34663853 PMCID: PMC8523663 DOI: 10.1038/s41598-021-99787-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 09/28/2021] [Indexed: 11/09/2022] Open
Abstract
White chanterelles (Basidiomycota), lacking the orange pigments and apricot-like odour of typical chanterelles, were found recently in the Canadian provinces of Québec (QC) and Newfoundland & Labrador (NL). Our phylogenetic analyses confirmed the identification of all white chanterelles from NL and QC as Cantharellus enelensis; we name these forma acolodorus. We characterized carotenoid pigments, lipids, phenolics, and volatile compounds in these and related chanterelles. White mutants of C. enelensis lacked detectable β-carotene, confirmed to be the primary pigment of wild-type, golden-orange individuals, and could also be distinguished by their profiles of fatty acids and phenolic acids, and by the ketone and terpene composition of their volatiles. We detected single base substitutions in the phytoene desaturase (Al-1) and phytoene synthase (Al-2) genes of the white mutant, which are predicted to result in altered amino acids in their gene products and may be responsible for the loss of β-carotene synthesis in that form.
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Affiliation(s)
- R Greg Thorn
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON, N6A 5B7, Canada.
| | - Alicia Banwell
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON, N6A 5B7, Canada
| | - Thu Huong Pham
- School of Science and the Environment, Grenfell Campus, Memorial University, 20 University Drive, Corner Brook, NL, A2H 5G4, Canada
| | - Natalia P Vidal
- School of Science and the Environment, Grenfell Campus, Memorial University, 20 University Drive, Corner Brook, NL, A2H 5G4, Canada.,Department of Food Science, iFOOD Multidisciplinary Center, Aarhus University, Agro Food Park 48, 8200, Aarhus N, Denmark
| | - Charles Felix Manful
- School of Science and the Environment, Grenfell Campus, Memorial University, 20 University Drive, Corner Brook, NL, A2H 5G4, Canada
| | - Muhammad Nadeem
- School of Science and the Environment, Grenfell Campus, Memorial University, 20 University Drive, Corner Brook, NL, A2H 5G4, Canada
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON, N6A 5B7, Canada.,Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Beth Szyszka Mroz
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON, N6A 5B7, Canada
| | - Michael B Bonneville
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON, N6A 5B7, Canada
| | - Norman Peter Andrew Hüner
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON, N6A 5B7, Canada
| | - Michele D Piercey-Normore
- School of Science and the Environment, Grenfell Campus, Memorial University, 20 University Drive, Corner Brook, NL, A2H 5G4, Canada
| | - Raymond Thomas
- School of Science and the Environment, Grenfell Campus, Memorial University, 20 University Drive, Corner Brook, NL, A2H 5G4, Canada
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7
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Maday DY, Kozlov VK, Ivanov AG, Besaev GM, Madai OD. [Medical tactics, approaches and complex treatment effectiveness in case of multiple trauma caused by a fall from a height]. Khirurgiia (Mosk) 2021:69-75. [PMID: 34363448 DOI: 10.17116/hirurgia202108169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To demonstrate the approaches' implementation of specialized multidisciplinary and high-tech medical care in multistage complex treatment of patient with multiple trauma including combined severe trauma of the maxillofacial region such as minimally invasive surgical tactics with early and delayed osteosynthesis (e.g. selection of optimal surgical tactics within the periodization of traumatic disease concept). Moreover, the implementation of rational advanced intensive pathogenesis drug therapy with the prevention of infectious complications in cast of severe injuries. MATERIAL AND METHODS The tactics, approaches and results of multistage complex specialized treatment of patient K., 56 years old who has got severe concomitant injuries to various areas of the body and extremities (including multiple maxillofacial trauma) after falling from a height are presented. CONCLUSION Rational surgical tactics and the timely initiation (immediately after admission of the victim to 1st level trauma center) of pathogenesis intensive therapy with modern drugs and antibiotics contributed to the exclusion of infectious complications in the third period (the period of maximum likelihood of complications) of traumatic illness. Comprehensive treatment of a victim with multiple trauma based on the principles of specialized, multidisciplinary and high-tech medical care is able to provide a favorable clinical outcome - the recovery with the restoration of the damaged anatomical structures functionality and the absence of cosmetic defects.
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Affiliation(s)
- D Yu Maday
- St. Petersburg State University, St. Petersburg, Russia.,I.I. Janelidze St. Petersburg Research Institute of Emergency Medicine, St. Petersburg, Russia
| | - V K Kozlov
- St. Petersburg State University, St. Petersburg, Russia.,Academician S.N. Golikov Scientific and Clinical Center of Toxicology, St. Petersburg, Russia
| | - A G Ivanov
- St. Petersburg State University, St. Petersburg, Russia.,I.I. Janelidze St. Petersburg Research Institute of Emergency Medicine, St. Petersburg, Russia
| | - G M Besaev
- I.I. Janelidze St. Petersburg Research Institute of Emergency Medicine, St. Petersburg, Russia
| | - O D Madai
- St. Petersburg State University, St. Petersburg, Russia
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Bag P, Chukhutsina V, Zhang Z, Paul S, Ivanov AG, Shutova T, Croce R, Holzwarth AR, Jansson S. Direct energy transfer from photosystem II to photosystem I confers winter sustainability in Scots Pine. Nat Commun 2020; 11:6388. [PMID: 33319777 PMCID: PMC7738668 DOI: 10.1038/s41467-020-20137-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/13/2020] [Indexed: 11/24/2022] Open
Abstract
Evergreen conifers in boreal forests can survive extremely cold (freezing) temperatures during long dark winter and fully recover during summer. A phenomenon called “sustained quenching” putatively provides photoprotection and enables their survival, but its precise molecular and physiological mechanisms are not understood. To unveil them, here we have analyzed seasonal adjustment of the photosynthetic machinery of Scots pine (Pinus sylvestris) trees by monitoring multi-year changes in weather, chlorophyll fluorescence, chloroplast ultrastructure, and changes in pigment-protein composition. Analysis of Photosystem II and Photosystem I performance parameters indicate that highly dynamic structural and functional seasonal rearrangements of the photosynthetic apparatus occur. Although several mechanisms might contribute to ‘sustained quenching’ of winter/early spring pine needles, time-resolved fluorescence analysis shows that extreme down-regulation of photosystem II activity along with direct energy transfer from photosystem II to photosystem I play a major role. This mechanism is enabled by extensive thylakoid destacking allowing for the mixing of PSII with PSI complexes. These two linked phenomena play crucial roles in winter acclimation and protection. Evergreen conifers rely on ‘sustained quenching’ to protect their photosynthetic machinery during long, cold winters. Here, Bag et al. show that direct energy transfer (spillover) from photosystem II to photosystem I triggered by loss of grana stacking in chloroplast is the major component of sustained quenching in Scots pine.
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Affiliation(s)
- Pushan Bag
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Volha Chukhutsina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Department of Life Sciences, Imperial College London, London, UK
| | - Zishan Zhang
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.,State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Shandong, China
| | - Suman Paul
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.,Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, London, Ontario, Canada.,Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Tatyana Shutova
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Alfred R Holzwarth
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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9
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Velitchkova M, Popova AV, Faik A, Gerganova M, Ivanov AG. Low temperature and high light dependent dynamic photoprotective strategies in Arabidopsis thaliana. Physiol Plant 2020; 170:93-108. [PMID: 32315446 DOI: 10.1111/ppl.13111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 06/11/2023]
Abstract
Arabidopsis thaliana has been recognized as a chilling tolerant species based on analysis of resistance to low temperature stress, however, the mechanisms involved in this tolerance are not yet clarified. The low temperature-induced effects are exacerbated when plants are exposed to low temperatures in the presence of high light irradiance but the experimental data on the impact of light intensity during cold stress and its influence during recovery from stress are rather limited. The main objective of this study was to re-examine the photosynthetic responses of A. thaliana plants to short term (6 days) low temperature stress (12/10°C) under optimal (150 μmol m-2 s-1 ) and high light (500 μmol m-2 s-1 ) intensity and the subsequent recovery from the stress. Simultaneous measurements of the in vivo and in vitro functional performance of both photosystem II (PSII) and photosystem I (PSI), as well as, net photosynthesis, low temperature (77 K) chlorophyll fluorescence and immunoblot analysis of the relative abundance of PSII and PSI reaction center proteins were used to evaluate the role of light in the development of possible protective mechanisms during low temperature stress and the consequent recovery from exposure to low temperature and different light intensities. The results presented clearly suggest that Arabidopsis plants can employ a number of highly dynamic photoprotective strategies depending on the light intensity. These strategies include one based on LHCII quenching and two other quenching mechanisms localized within the PSII and PSI reaction centers, which are all expressed to different extent depending on the severity of the photoinhibitory treatments under low temperature stress conditions.
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Affiliation(s)
- Maya Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Antoaneta V Popova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Aygyun Faik
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Milena Gerganova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Alexander G Ivanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
- Department of Biology, University of Western Ontario, 1151 Richmond Str. N, London, Ontario, N6A 5B7, Canada
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Chaudhury A, Ward C, Talasaz A, Ivanov AG, Brophy M, Grodzinski B, Huner NPA, Patel RV, Barron JL. Machine Vision System for 3D Plant Phenotyping. IEEE/ACM Trans Comput Biol Bioinform 2019; 16:2009-2022. [PMID: 29993836 DOI: 10.1109/tcbb.2018.2824814] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Machine vision for plant phenotyping is an emerging research area for producing high throughput in agriculture and crop science applications. Since 2D based approaches have their inherent limitations, 3D plant analysis is becoming state of the art for current phenotyping technologies. We present an automated system for analyzing plant growth in indoor conditions. A gantry robot system is used to perform scanning tasks in an automated manner throughout the lifetime of the plant. A 3D laser scanner mounted as the robot's payload captures the surface point cloud data of the plant from multiple views. The plant is monitored from the vegetative to reproductive stages in light/dark cycles inside a controllable growth chamber. An efficient 3D reconstruction algorithm is used, by which multiple scans are aligned together to obtain a 3D mesh of the plant, followed by surface area and volume computations. The whole system, including the programmable growth chamber, robot, scanner, data transfer, and analysis is fully automated in such a way that a naive user can, in theory, start the system with a mouse click and get back the growth analysis results at the end of the lifetime of the plant with no intermediate intervention. As evidence of its functionality, we show and analyze quantitative results of the rhythmic growth patterns of the dicot Arabidopsis thaliana (L.), and the monocot barley (Hordeum vulgare L.) plants under their diurnal light/dark cycles.
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11
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Szyszka-Mroz B, Cvetkovska M, Ivanov AG, Smith DR, Possmayer M, Maxwell DP, Hüner NPA. Cold-Adapted Protein Kinases and Thylakoid Remodeling Impact Energy Distribution in an Antarctic Psychrophile. Plant Physiol 2019; 180:1291-1309. [PMID: 31019005 PMCID: PMC6752925 DOI: 10.1104/pp.19.00411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 04/09/2019] [Indexed: 05/05/2023]
Abstract
The Antarctic psychrophile Chlamydomonas sp. UWO241 evolved in a permanently ice-covered lake whose aquatic environment is characterized not only by constant low temperature and high salt but also by low light during the austral summer coupled with 6 months of complete darkness during the austral winter. Since the UWO241 genome indicated the presence of Stt7 and Stl1 protein kinases, we examined protein phosphorylation and the state transition phenomenon in this psychrophile. Light-dependent [γ-33P]ATP labeling of thylakoid membranes from Chlamydomonas sp. UWO241 exhibited a distinct low temperature-dependent phosphorylation pattern compared to Chlamydomonas reinhardtii despite comparable levels of the Stt7 protein kinase. The sequence and structure of the UWO241 Stt7 kinase domain exhibits substantial alterations, which we suggest predisposes it to be more active at low temperature. Comparative purification of PSII and PSI combined with digitonin fractionation of thylakoid membranes indicated that UWO241 altered its thylakoid membrane architecture and reorganized the distribution of PSI and PSII units between granal and stromal lamellae. Although UWO241 grown at low salt and low temperature exhibited comparable thylakoid membrane appression to that of C. reinhardtii at its optimal growth condition, UWO241 grown under its natural condition of high salt resulted in swelling of the thylakoid lumen. This was associated with an upregulation of PSI cyclic electron flow by 50% compared to growth at low salt. Due to the unique 77K fluorescence emission spectra of intact UWO241 cells, deconvolution was necessary to detect enhancement in energy distribution between PSII and PSI, which was sensitive to the redox state of the plastoquinone pool and to the NaCl concentrations of the growth medium. We conclude that a reorganization of PSII and PSI in UWO241 results in a unique state transition phenomenon that is associated with altered protein phosphorylation and enhanced PSI cyclic electron flow. These data are discussed with respect to a possible PSII-PSI energy spillover mechanism that regulates photosystem energy partitioning and quenching.
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Affiliation(s)
- Beth Szyszka-Mroz
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
| | - Marina Cvetkovska
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
| | - Alexander G Ivanov
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113 Sofia, Bulgaria
| | - David R Smith
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
| | - Marc Possmayer
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
| | - Denis P Maxwell
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
| | - Norman P A Hüner
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Canada N6A 5B7
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12
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Hollis L, Ivanov AG, Hüner NPA. Chlorella vulgaris integrates photoperiod and chloroplast redox signals in response to growth at high light. Planta 2019; 249:1189-1205. [PMID: 30603788 DOI: 10.1007/s00425-018-03070-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 12/17/2018] [Indexed: 05/28/2023]
Abstract
Photoacclimation to variable light and photoperiod regimes in C. vulgaris represents a complex interplay between "biogenic" phytochrome-mediated sensing and "operational" redox sensing signaling pathways. Chlorella vulgaris Beijerinck UTEX 265 exhibits a yellow-green phenotype when grown under high light (HL) in contrast to a dark green phenotype when grown at low light (LL). The redox state of the photosynthetic electron transport chain (PETC) as estimated by excitation pressure has been proposed to govern this phenotypic response. We hypothesized that if the redox state of the PETC was the sole regulator of the HL phenotype, C. vulgaris should photoacclimate in response to the steady-state excitation pressure during the light period regardless of the length of the photoperiod. As expected, LL-grown cells exhibited a dark green phenotype, low excitation pressure (1 - qP = 0.22 ± 0.02), high chlorophyll (Chl) content (375 ± 77 fg Chl/cell), low Chl a/b ratio (2.97 ± 0.18) as well as high photosynthetic efficiency and photosynthetic capacity regardless of the photoperiod. In contrast, C. vulgaris grown under continuous HL developed a yellow-green phenotype characterized by high excitation pressure (1 - qP = 0.68 ± 0.01), a relatively low Chl content (180 ± 53 fg Chl/cell), high Chl a/b ratio (6.36 ± 0.54) with concomitantly reduced light-harvesting polypeptide abundance, as well as low photosynthetic capacity and efficiency measured on a per cell basis. Although cells grown under HL and an 18 h photoperiod developed a typical yellow-green phenotype, cells grown at HL but a 12 h photoperiod exhibited a dark green phenotype comparable to LL-grown cells despite exhibiting growth under high excitation pressure (1 - qP = 0.80 ± 0.04). The apparent uncoupling of excitation pressure and phenotype in HL-grown cells and a 12 h photoperiod indicates that chloroplast redox status cannot be the sole regulator of photoacclimation in C. vulgaris. We conclude that photoacclimation in C. vulgaris to HL is dependent upon growth history and reflects a complex interaction of endogenous systems that sense changes in photoperiod as well as photosynthetic redox balance.
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Affiliation(s)
- Lauren Hollis
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada
| | - Alexander G Ivanov
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
| | - Norman P A Hüner
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
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13
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Popova AV, Dobrev K, Velitchkova M, Ivanov AG. Differential temperature effects on dissipation of excess light energy and energy partitioning in lut2 mutant of Arabidopsis thaliana under photoinhibitory conditions. Photosynth Res 2019; 139:367-385. [PMID: 29725995 DOI: 10.1007/s11120-018-0511-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/22/2018] [Indexed: 06/08/2023]
Abstract
The high-light-induced alterations in photosynthetic performance of photosystem II (PSII) and photosystem I (PSI) as well as effectiveness of dissipation of excessive absorbed light during illumination for different periods of time at room (22 °C) and low (8-10 °C) temperature of leaves of Arabidopsis thaliana, wt and lut2, were followed with the aim of unraveling the role of lutein in the process of photoinhibition. Photosynthetic parameters of PSII and PSI were determined on whole leaves by PAM fluorometer and oxygen evolving activity-by a Clark-type electrode. In thylakoid membranes, isolated from non-illuminated and illuminated for 4.5 h leaves of wt and lut2 the photochemical activity of PSII and PSI and energy interaction between the main pigment-protein complexes was determined. Results indicate that in non-illuminated leaves of lut2 the maximum rate of oxygen evolution and energy utilization in PSII is lower, excitation pressure of PSII is higher and cyclic electron transport around PSI is faster than in wt leaves. Under high-light illumination, lut2 leaves are more sensitive in respect to PSII performance and the extent of increase of excitation pressure of PSII, ΦNO, and cyclic electron transport around PSI are higher than in wt leaves, especially when illumination is performed at low temperature. Significant part of the excessive light energy is dissipated via mechanism, not dependent on ∆pH and to functioning of xanthophyll cycle in LHCII, operating more intensively in lut2 leaves.
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Affiliation(s)
- Antoaneta V Popova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria.
| | - Konstantin Dobrev
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria
| | - Maya Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria
| | - Alexander G Ivanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria
- Department of Biology, University of Western Ontario, 1151 Richmond Str. N., London, ON, N6A 5B7, Canada
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Kurepin LV, Stangl ZR, Ivanov AG, Bui V, Mema M, Hüner NPA, Öquist G, Way D, Hurry V. Contrasting acclimation abilities of two dominant boreal conifers to elevated CO 2 and temperature. Plant Cell Environ 2018; 41:1331-1345. [PMID: 29411877 DOI: 10.1111/pce.13158] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 01/04/2018] [Accepted: 01/21/2018] [Indexed: 05/22/2023]
Abstract
High latitude forests will experience large changes in temperature and CO2 concentrations this century. We evaluated the effects of future climate conditions on 2 dominant boreal tree species, Pinus sylvestris L. and Picea abies (L.) H. Karst, exposing seedlings to 3 seasons of ambient (430 ppm) or elevated CO2 (750 ppm) and ambient temperatures, a + 4 °C warming or a + 8 °C warming. Pinus sylvestris responded positively to warming: seedlings developed a larger canopy, maintained high net CO2 assimilation rates (Anet ), and acclimated dark respiration (Rdark ). In contrast, carbon fluxes in Picea abies were negatively impacted by warming: maximum rates of Anet decreased, electron transport was redirected to alternative electron acceptors, and thermal acclimation of Rdark was weak. Elevated CO2 tended to exacerbate these effects in warm-grown Picea abies, and by the end of the experiment Picea abies from the +8 °C, high CO2 treatment produced fewer buds than they had 3 years earlier. Treatments had little effect on leaf and wood anatomy. Our results highlight that species within the same plant functional type may show opposite responses to warming and imply that Picea abies may be particularly vulnerable to warming due to low plasticity in photosynthetic and respiratory metabolism.
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Affiliation(s)
- Leonid V Kurepin
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, 901 87, Sweden
- Department of Biology and the Biotron Center for Experimental Climate Change Research, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Zsofia R Stangl
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, 901 87, Sweden
| | - Alexander G Ivanov
- Department of Biology and the Biotron Center for Experimental Climate Change Research, University of Western Ontario, London, Ontario, N6A 5B7, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria
| | - Vi Bui
- Department of Biology and the Biotron Center for Experimental Climate Change Research, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Marin Mema
- Department of Biology and the Biotron Center for Experimental Climate Change Research, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Norman P A Hüner
- Department of Biology and the Biotron Center for Experimental Climate Change Research, University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Gunnar Öquist
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, 901 87, Sweden
| | - Danielle Way
- Department of Biology and the Biotron Center for Experimental Climate Change Research, University of Western Ontario, London, Ontario, N6A 5B7, Canada
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Vaughan Hurry
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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15
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Elkhouni A, Rabhi M, Ivanov AG, Krol M, Zorrig W, Smaoui A, Abdelly C, Huner NPA. Structural and functional integrity of Sulla carnosa photosynthetic apparatus under iron deficiency conditions. Plant Biol (Stuttg) 2018; 20:415-425. [PMID: 29274120 DOI: 10.1111/plb.12684] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 12/15/2017] [Indexed: 06/07/2023]
Abstract
The abundance of calcareous soils makes bicarbonate-induced iron (Fe) deficiency a major problem for plant growth and crop yield. Therefore, Fe-efficient plants may constitute a solution for use on calcareous soils. We investigated the ability of the forage legume Sulla carnosa (Desf.) to maintain integrity of its photosynthetic apparatus under Fe deficiency conditions. Three treatments were applied: control, direct Fe deficiency and bicarbonate-induced Fe deficiency. At harvest, all organs of deficient plants showed severe growth inhibition, the effect being less pronounced under indirect Fe deficiency. Pigment analysis of fully expanded leaves revealed a reduction in concentrations of chlorophyll a, chlorophyll b and carotenoids under Fe deficiency. Electron transport rate, maximum and effective quantum yield of photosystem II (PSII), photochemical quenching (qP), non-photochemical quenching (qN) as well as P700 activity also decreased significantly in plants exposed to direct Fe deficiency, while qN was not affected. The effects of indirect Fe deficiency on the same parameters were less pronounced in bicarbonate-treated plants. The relative abundances of thylakoid proteins related to PSI (PsaA, Lhca1, Lhca2) and PSII (PsbA, Lhcb1) were also more affected under direct than indirect Fe deficiency. We conclude that S. carnosa can maintain the integrity of its photosynthetic apparatus under bicarbonate-induced Fe deficiency, preventing harmful effects to both photosystems under direct Fe deficiency. This suggests a high capacity of this species not only to take up Fe in the presence of bicarbonate (HCO3- ) but also to preferentially translocate absorbed Fe towards leaves and prevent its inactivation.
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Affiliation(s)
- A Elkhouni
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - M Rabhi
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - A G Ivanov
- Department of Biology, University of Western Ontario, London, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - M Krol
- Department of Biology, University of Western Ontario, London, Canada
| | - W Zorrig
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - A Smaoui
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - C Abdelly
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - N P A Huner
- Department of Biology, University of Western Ontario, London, Canada
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16
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Ivanov AG, Velitchkova MY, Allakhverdiev SI, Huner NPA. Heat stress-induced effects of photosystem I: an overview of structural and functional responses. Photosynth Res 2017; 133:17-30. [PMID: 28391379 DOI: 10.1007/s11120-017-0383-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/03/2017] [Indexed: 05/24/2023]
Abstract
Temperature is one of the main factors controlling the formation, development, and functional performance of the photosynthetic apparatus in all photoautotrophs (green plants, algae, and cyanobacteria) on Earth. The projected climate change scenarios predict increases in air temperature across Earth's biomes ranging from moderate (3-4 °C) to extreme (6-8 °C) by the year 2100 (IPCC in Climate change 2007: The physical science basis: summery for policymakers, IPCC WG1 Fourth Assessment Report 2007; Climate change 2014: Mitigation of Climate Change, IPCC WG3 Fifth Assessment Report 2014). In some areas, especially of the Northern hemisphere, even more extreme warm seasonal temperatures may occur, which possibly will cause significant negative effects on the development, growth, and yield of important agricultural crops. It is well documented that high temperatures can cause direct damages of the photosynthetic apparatus and photosystem II (PSII) is generally considered to be the primary target of heat-induced inactivation of photosynthesis. However, since photosystem I (PSI) is considered to determine the global amount of enthalpy in living systems (Nelson in Biochim Biophys Acta 1807:856-863, 2011; Photosynth Res 116:145-151, 2013), the effects of elevated temperatures on PSI might be of vital importance for regulating the photosynthetic response of all photoautotrophs in the changing environment. In this review, we summarize the experimental data that demonstrate the critical impact of heat-induced alterations on the structure, composition, and functional performance of PSI and their significant implications on photosynthesis under future climate change scenarios.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology, University of Western Ontario, 1151 Richmond Street N., London, ON, N6A 5B7, Canada.
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 21, 1113, Sofia, Bulgaria.
| | - Maya Y Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 21, 1113, Sofia, Bulgaria
| | - Suleyman I Allakhverdiev
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276, Russia
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow, 142290, Russia
- Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, 119991, Russia
- Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, 1073, Baku, Azerbaijan
| | - Norman P A Huner
- Department of Biology, University of Western Ontario, 1151 Richmond Street N., London, ON, N6A 5B7, Canada
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17
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Hüner NPA, Dahal K, Bode R, Kurepin LV, Ivanov AG. Photosynthetic acclimation, vernalization, crop productivity and 'the grand design of photosynthesis'. J Plant Physiol 2016; 203:29-43. [PMID: 27185597 DOI: 10.1016/j.jplph.2016.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/22/2016] [Accepted: 04/22/2016] [Indexed: 05/23/2023]
Abstract
Daniel Arnon first proposed the notion of a 'grand design of photosynthesis' in 1982 to illustrate the central role of photosynthesis as the primary energy transformer for all life on Earth. However, we suggest that this concept can be extended to the broad impact of photosynthesis not only in global energy transformation but also in the regulation of plant growth, development, survival and crop productivity through chloroplast redox signalling. We compare and contrast the role of chloroplast redox imbalance, measured as excitation pressure, in governing acclimation to abiotic stress and phenotypic plasticity. Although all photoautrophs sense excessive excitation energy through changes in excitation pressure, the response to this chloroplast redox signal is species dependent. Due to a limited capacity to adjust metabolic sinks, cyanobacteria and green algae induce photoprotective mechanisms which dissipate excess excitation energy at a cost of decreased photosynthetic performance. In contrast, terrestrial, cold tolerant plants such as wheat enhance metabolic sink capacity which leads to enhanced photosynthetic performance and biomass accumulation with minimal dependence on photoprotection. We suggest that the family of nuclear C-repeat binding transcription factors (CBFs) associated with the frost resistance locus, FR2, contiguous with the vernalization locus,VRN1, and mapped to chromosome 5A of wheat, may be critical components that link leaf chloroplast redox regulation to enhanced photosynthetic performance, the accumulation of growth-active gibberellins and the dwarf phenotype during cold acclimation prior to the vegetative to reproductive transition controlled by vernalization in winter cereals. Further genetic, molecular and biochemical research to confirm these links and to elucidate the molecular mechanism by which chloroplast redox modulation of CBF expression leads to enhanced photosynthetic performance is required. Because of the superior abiotic stress tolerance of cold tolerant winter wheat and seed yields that historically exceed those of spring wheat by 30-40%, we discuss the potential to exploit winter cereals for the maintenance or perhaps even the enhancement of cereal productivity under future climate change scenarios that will be required to feed a growing human population.
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Affiliation(s)
- Norman P A Hüner
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London N6A 5B7, Canada.
| | - Keshav Dahal
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C 1A4, Canada
| | - Rainer Bode
- Institute of Biology, Freie Universitat, Königin-Luise-Straße 12-16, 14195 Berlin, Germany
| | - Leonid V Kurepin
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London N6A 5B7, Canada
| | - Alexander G Ivanov
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London N6A 5B7, Canada
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18
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McCarthy A, Chung M, Ivanov AG, Krol M, Inman M, Maxwell DP, Hüner NPA. An established Arabidopsis thaliana var. Landsberg erecta cell suspension culture accumulates chlorophyll and exhibits a stay-green phenotype in response to high external sucrose concentrations. J Plant Physiol 2016; 199:40-51. [PMID: 27302005 DOI: 10.1016/j.jplph.2016.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 05/12/2016] [Accepted: 05/13/2016] [Indexed: 06/06/2023]
Abstract
An established cell suspension culture of Arabidopsis thaliana var. Landsberg erecta was grown in liquid media containing 0-15%(w/v) sucrose. Exponential growth rates of about 0.40d-1 were maintained between 1.5-6%(w/v) sucrose, which decreased to about 0.30d-1 between 6 and 15%(w/v) sucrose. Despite the presence of external sucrose, cells maintained a stay-green phenotype at 0-15% (w/v) sucrose. Sucrose stimulated transcript levels of genes involved in the chlorophyll biosynthetic pathway (ChlH, ChlI2, DVR). Although most of the genes associated with photosystem II and photosystem I reaction centers and light harvesting complexes as well as genes associated with the cytochrome b6f and the ATP synthase complexes were downregulated or remained unaffected by high sucrose, immunoblotting indicated that protein levels of PsaA, Lhcb2 and Rubisco per gram fresh weight changed minimallyon a Chl basis as a function of external sucrose concentration. The green cell culture was photosynthetically competent based on light-dependent, CO2-saturated rates of O2 evolution as well as Fv/Fm and P700 oxidation. Similar to Arabidopsis WT seedlings, the suspension cells etiolated in the dark and but remained green in the light. However, the exponential growth rate of the cell suspension cultures in the dark (0.45±0.07d-1) was comparable to that in the light (0.42±0.02d-1). High external sucrose levels induced feedback inhibition of photosynthesis as indicated by the increase in excitation pressure measured as a function of external sucrose concentration. Regardless, the cell suspension culture still maintained a stay-green phenotype in the light at sucrose concentrations from 0 to 15%(w/v) due, in part, to a stimulation of photoprotection through nonphotochemical quenching. The stay-green, sugar-insensitive phenotype of the cell suspension contrasted with the sugar-dependent, non-green phenotype of Arabidopsis Landsberg erecta WT seedlings grown at comparable external sucrose concentrations. It appears that the commonly used Arabidopsis thaliana var. Landsberg erecta cell suspension culture has undergone significant genetic change since its original generation in 1993. We suggest that this genetic alteration has inhibited the sucrose sensing/signaling pathway coupled with a stimulation of chlorophyll an accumulation in the light with minimal effects on the composition and function of its photosynthetic apparatus. Therefore, caution must be exercised in the interpretation of physiological and biochemical data obtained from experimental use of this culture in any comparison with wild-type Arabidopsis seedlings.
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Affiliation(s)
- Avery McCarthy
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
| | - Michelle Chung
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
| | - Alexander G Ivanov
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
| | - Marianna Krol
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
| | - Michael Inman
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
| | - Denis P Maxwell
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
| | - Norman P A Hüner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7 Canada,.
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19
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Bode R, Ivanov AG, Hüner NPA. Global transcriptome analyses provide evidence that chloroplast redox state contributes to intracellular as well as long-distance signalling in response to stress and acclimation in Arabidopsis. Photosynth Res 2016; 128:287-312. [PMID: 27021769 DOI: 10.1007/s11120-016-0245-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 03/10/2016] [Indexed: 05/03/2023]
Abstract
Global transcriptome analyses were used to assess the interactive effects of short-term stress versus long-term acclimation to high light (HL), low temperature (LT) and excitation pressure in Arabidopsis. Microarray analyses indicated that exposure to stress resulted in two times as many modulated transcripts in both, high-light-treated and low-temperature-treated plants, compared to plants that were fully acclimated to either one of these conditions. We showed that 10.9 % of all transcripts were regulated in the same way by both stress conditions, and hence, were categorized as excitation pressure regulated, rather than regulated by either high-light or low-temperature stress per se. This group of chloroplast redox-sensitive genes included various photosynthetic genes as well as genes known to be associated with cold acclimation (cbf3, cor15A, cor15B) and gibberellic acid (GA) metabolism and signalling (ga2ox1, gai). Chemical inhibition of the photosynthetic electron transport by either DCMU or DBMIB indicated that although the plastoquinone pool contributes significantly to redox regulation of the transcriptome (8.6 %), it appears that PSI represents the major source of redox signals (89 %), whereas PSII appears to contribute only 3.1 %. A comparison of the gene expression profiles between stress and acclimated plants indicated that 10 % of the genes induced by a short, 1-h stress were also associated with long-term acclimation to high excitation pressure. This included the APETALA2/ETHYLENE-RESPONSIVE-BINDING PROTEIN family, the MYB domain- and MYB-related transcription factor family as well as the GRAS transcription factor family important in GA signalling confirming that acclimation to stress is a time-nested phenomenon. We suggest that acclimation to photosynthetic redox imbalance extends beyond the chloroplast and the leaf cell to systemic ROS signalling. This is discussed in terms of the control of plant phenotype through regulation of the nuclear encoded cbf regulon and GA metabolism.
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Affiliation(s)
- Rainer Bode
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, ON, N6A 5B7, Canada
- Department of Biology, Chemistry and Pharmacy, Institute of Biology - Physiology of Plants, Freie Universität Berlin, Königin-Luise-Straße 12-16, 14195, Berlin, Germany
| | - Alexander G Ivanov
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, ON, N6A 5B7, Canada
| | - Norman P A Hüner
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, ON, N6A 5B7, Canada.
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Flores-Bavestrello A, Król M, Ivanov AG, Hüner NPA, García-Plazaola JI, Corcuera LJ, Bravo LA. Two Hymenophyllaceae species from contrasting natural environments exhibit a homoiochlorophyllous strategy in response to desiccation stress. J Plant Physiol 2016; 191:82-94. [PMID: 26720213 DOI: 10.1016/j.jplph.2015.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 12/07/2015] [Accepted: 12/10/2015] [Indexed: 05/28/2023]
Abstract
Hymenophyllaceae is a desiccation tolerant family of Pteridophytes which are poikilohydric epiphytes. Their fronds are composed by a single layer of cells and lack true mesophyll cells and stomata. Although they are associated with humid and shady environments, their vertical distribution varies along the trunk of the host plant with some species inhabiting the drier sides with a higher irradiance. The aim of this work was to compare the structure and function of the photosynthetic apparatus during desiccation and rehydration in two species, Hymenophyllum dentatum and Hymenoglossum cruentum, isolated from a contrasting vertical distribution along the trunk of their hosts. Both species were subjected to desiccation and rehydration kinetics to analyze frond phenotypic plasticity, as well as the structure, composition and function of the photosynthetic apparatus. Minimal differences in photosynthetic pigments were observed upon dehydration. Measurements of ϕPSII (effective quantum yield of PSII), ϕNPQ (quantum yield of the regulated energy dissipation of PSII), ϕNO (quantum yield of non-regulated energy dissipation of PSII), and TL (thermoluminescence) indicate that both species convert a functional photochemical apparatus into a structure which exhibits maximum quenching capacity in the dehydrated state with minimal changes in photosynthetic pigments and polypeptide compositions. This dehydration-induced conversion in the photosynthetic apparatus is completely reversible upon rehydration. We conclude that H. dentatum and H. cruentum are homoiochlorophyllous with respect to desiccation stress and exhibited no correlation between inherent desiccation tolerance and the vertical distribution along the host tree trunk.
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Affiliation(s)
| | - Marianna Król
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, Ontario, N6A 5B7, Canada.
| | - Alexander G Ivanov
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, Ontario, N6A 5B7, Canada.
| | - Norman P A Hüner
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, Ontario, N6A 5B7, Canada.
| | - José Ignacio García-Plazaola
- Departamento de Biología Vegetal y Ecología, Universidad del País Vasco (UPV/EHU), Aptdo. 644, E-48080 Bilbao, Spain.
| | - Luis J Corcuera
- Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Chile.
| | - León A Bravo
- Departamento de Ciencias Agronómicas y Recursos Naturales, Facultad de Ciencias Agronómicas y Forestales, Universidad de La Frontera, Chile; Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Chile.
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Kurepin LV, Ivanov AG, Zaman M, Pharis RP, Allakhverdiev SI, Hurry V, Hüner NPA. Stress-related hormones and glycinebetaine interplay in protection of photosynthesis under abiotic stress conditions. Photosynth Res 2015; 126:221-35. [PMID: 25823797 DOI: 10.1007/s11120-015-0125-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/20/2015] [Indexed: 05/03/2023]
Abstract
Plants subjected to abiotic stresses such as extreme high and low temperatures, drought or salinity, often exhibit decreased vegetative growth and reduced reproductive capabilities. This is often associated with decreased photosynthesis via an increase in photoinhibition, and accompanied by rapid changes in endogenous levels of stress-related hormones such as abscisic acid (ABA), salicylic acid (SA) and ethylene. However, certain plant species and/or genotypes exhibit greater tolerance to abiotic stress because they are capable of accumulating endogenous levels of the zwitterionic osmolyte-glycinebetaine (GB). The accumulation of GB via natural production, exogenous application or genetic engineering, enhances plant osmoregulation and thus increases abiotic stress tolerance. The final steps of GB biosynthesis occur in chloroplasts where GB has been shown to play a key role in increasing the protection of soluble stromal and lumenal enzymes, lipids and proteins, of the photosynthetic apparatus. In addition, we suggest that the stress-induced GB biosynthesis pathway may well serve as an additional or alternative biochemical sink, one which consumes excess photosynthesis-generated electrons, thus protecting photosynthetic apparatus from overreduction. Glycinebetaine biosynthesis in chloroplasts is up-regulated by increases in endogenous ABA or SA levels. In this review, we propose and discuss a model describing the close interaction and synergistic physiological effects of GB and ABA in the process of cold acclimation of higher plants.
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Affiliation(s)
- Leonid V Kurepin
- Department of Biology and The Biotron Center for Experimental Climate Change Research, University of Western Ontario (Western University), 1151 Richmond Street N., London, ON, N6A 5B7, Canada.
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden.
| | - Alexander G Ivanov
- Department of Biology and The Biotron Center for Experimental Climate Change Research, University of Western Ontario (Western University), 1151 Richmond Street N., London, ON, N6A 5B7, Canada.
| | - Mohammad Zaman
- Soil and Water Management and Crop Nutrition Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna International Centre, PO Box 100, 1400, Vienna, Austria
| | - Richard P Pharis
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Suleyman I Allakhverdiev
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276, Russia
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142292, Russia
- Department of Plant Physiology, Faculty of Biology, M. V. Lomonosov Moscow State University, Leninskie Gory 1-12, Moscow, 119991, Russia
| | - Vaughan Hurry
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Norman P A Hüner
- Department of Biology and The Biotron Center for Experimental Climate Change Research, University of Western Ontario (Western University), 1151 Richmond Street N., London, ON, N6A 5B7, Canada
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Chibichyan MB, Kogan MI, Lapteva TO, Belousov II, Ivanov AG, Chernogubova EA. [Periprostatic inflammation as a risk factor for the development of vesico-urethral stenosis after radical prostatectomy]. Urologiia 2015:52-57. [PMID: 28247681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This article presents results of a study conducted to identify the causes of stenosis in the region of vesico-urethral anastomosis (VUA) after radical prostatectomy (RP). Tissue specimens from removed prostates were evaluated in 115 prostate cancer patients with a favorable postoperative period (group 1) and 5 patients who develop VUA stenosis between 6 months to1 year after RP. It was found that in the group 1 inflammatory infiltration did not basically affect tumor growth zones, was mild and did not spread beyond the prostate. Patients of the group 2 had maximum inflammation, with the inflammatory infiltration localized in the prostate regions, both affected and not affected by the tumor, and periprostatically. Taking into account more severe inflammatory response in the prostate with extracapsular extension of the process and the involvement of periprostatic structures in patients who developed VUA stenosis after RP, compared to those without VUA stenosis, we can consider this phenomenon as a risk factor for stenotic complications in the vesico-urethral segment after RP.
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Affiliation(s)
- M B Chibichyan
- Department of Molecular Biology, Institute of Arid Zones of Southern Scientific Center of RAS
- Department of Urology and Human Reproductive Health with Course of Pediatric Urology-Andrology, Scientific Research Institute of Urology and Nephrology, Rostov State Medical University of Minzdrav of Russia
| | - M I Kogan
- Department of Molecular Biology, Institute of Arid Zones of Southern Scientific Center of RAS
- Department of Urology and Human Reproductive Health with Course of Pediatric Urology-Andrology, Scientific Research Institute of Urology and Nephrology, Rostov State Medical University of Minzdrav of Russia
| | - T O Lapteva
- Regional Consultative and Diagnostic Centre Rostov-on-Don
| | - I I Belousov
- Department of Urology and Human Reproductive Health with Course of Pediatric Urology-Andrology, Scientific Research Institute of Urology and Nephrology, Rostov State Medical University of Minzdrav of Russia
| | - A G Ivanov
- Department of Urology and Human Reproductive Health with Course of Pediatric Urology-Andrology, Scientific Research Institute of Urology and Nephrology, Rostov State Medical University of Minzdrav of Russia
| | - E A Chernogubova
- Department of Molecular Biology, Institute of Arid Zones of Southern Scientific Center of RAS
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Ivanov AG, Morgan-Kiss RM, Krol M, Allakhverdiev SI, Zanev Y, Sane PV, Huner NPA. Photoinhibition of photosystem I in a pea mutant with altered LHCII organization. J Photochem Photobiol B 2015; 152:335-46. [PMID: 26321219 DOI: 10.1016/j.jphotobiol.2015.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/10/2015] [Accepted: 08/13/2015] [Indexed: 11/18/2022]
Abstract
Comparative analysis of in vivo chlorophyll fluorescence imaging revealed that photosystem II (PSII) photochemical efficiency (Fv/Fm) of leaves of the Costata 2/133 pea mutant with altered pigment composition and decreased level of oligomerization of the light harvesting chlorophyll a/b-protein complexes (LHCII) of PSII (Dobrikova et al., 2000; Ivanov et al., 2005) did not differ from that of WT. In contrast, photosystem I (PSI) activity of the Costata 2/133 mutant measured by the far-red (FR) light inducible P700 (P700(+)) signal exhibited 39% lower steady state level of P700(+), a 2.2-fold higher intersystem electron pool size (e(-)/P700) and higher rate of P700(+) re-reduction, which indicate an increased capacity for PSI cyclic electron transfer (CET) in the Costata 2/133 mutant than WT. The mutant also exhibited a limited capacity for state transitions. The lower level of oxidizable P700 (P700(+)) is consistent with a lower amount of PSI related chlorophyll protein complexes and lower abundance of the PsaA/PsaB heterodimer, PsaD and Lhca1 polypeptides in Costata 2/133 mutant. Exposure of WT and the Costata 2/133 mutant to high light stress resulted in a comparable photoinhibition of PSII measured in vivo, although the decrease of Fv/Fm was modestly higher in the mutant plants. However, under the same photoinhibitory conditions PSI photochemistry (P700(+)) measured as ΔA820-860 was inhibited to a greater extent (50%) in the Costata 2/133 mutant than in the WT (22%). This was accompanied by a 50% faster re-reduction rate of P700(+) in the dark indicating a higher capacity for CET around PSI in high light treated mutant leaves. The role of chloroplast thylakoid organization on the stability of the PSI complex and its susceptibility to high light stress is discussed.
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Affiliation(s)
- A G Ivanov
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, 1151 Richmond Street, N., London, Ontario N6A 5B7, Canada.
| | - R M Morgan-Kiss
- Department of Microbiology, Miami University, 700 E. High Street, Oxford, OH 45045, USA
| | - M Krol
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, 1151 Richmond Street, N., London, Ontario N6A 5B7, Canada
| | - S I Allakhverdiev
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia; Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Yu Zanev
- Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
| | - P V Sane
- Jain Irrigation Systems Limited, Jain Hills, Jalgaon 425001, India
| | - N P A Huner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, 1151 Richmond Street, N., London, Ontario N6A 5B7, Canada.
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Szyszka-Mroz B, Pittock P, Ivanov AG, Lajoie G, Hüner NPA. The Antarctic Psychrophile Chlamydomonas sp. UWO 241 Preferentially Phosphorylates a Photosystem I-Cytochrome b6/f Supercomplex. Plant Physiol 2015; 169:717-36. [PMID: 26169679 PMCID: PMC4577404 DOI: 10.1104/pp.15.00625] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/10/2015] [Indexed: 05/05/2023]
Abstract
Chlamydomonas sp. UWO 241 (UWO 241) is a psychrophilic green alga isolated from Antarctica. A unique characteristic of this algal strain is its inability to undergo state transitions coupled with the absence of photosystem II (PSII) light-harvesting complex protein phosphorylation. We show that UWO 241 preferentially phosphorylates specific polypeptides associated with an approximately 1,000-kD pigment-protein supercomplex that contains components of both photosystem I (PSI) and the cytochrome b₆/f (Cyt b₆/f) complex. Liquid chromatography nano-tandem mass spectrometry was used to identify three major phosphorylated proteins associated with this PSI-Cyt b₆/f supercomplex, two 17-kD PSII subunit P-like proteins and a 70-kD ATP-dependent zinc metalloprotease, FtsH. The PSII subunit P-like protein sequence exhibited 70.6% similarity to the authentic PSII subunit P protein associated with the oxygen-evolving complex of PSII in Chlamydomonas reinhardtii. Tyrosine-146 was identified as a unique phosphorylation site on the UWO 241 PSII subunit P-like polypeptide. Assessment of PSI cyclic electron transport by in vivo P700 photooxidation and the dark relaxation kinetics of P700(+) indicated that UWO 241 exhibited PSI cyclic electron transport rates that were 3 times faster and more sensitive to antimycin A than the mesophile control, Chlamydomonas raudensis SAG 49.72. The stability of the PSI-Cyt b₆/f supercomplex was dependent upon the phosphorylation status of the PsbP-like protein and the zinc metalloprotease FtsH as well as the presence of high salt. We suggest that adaptation of UWO 241 to its unique low-temperature and high-salt environment favors the phosphorylation of a PSI-Cyt b₆/f supercomplex to regulate PSI cyclic electron transport rather than the regulation of state transitions through the phosphorylation of PSII light-harvesting complex proteins.
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Affiliation(s)
- Beth Szyszka-Mroz
- Biology Department and Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Ontario, Canada N6A 5B7 (B.S.-M., A.G.I., N.P.A.H.); andDepartment of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, Ontario, Canada N6G 2V4 (P.P., G.L.)
| | - Paula Pittock
- Biology Department and Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Ontario, Canada N6A 5B7 (B.S.-M., A.G.I., N.P.A.H.); andDepartment of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, Ontario, Canada N6G 2V4 (P.P., G.L.)
| | - Alexander G Ivanov
- Biology Department and Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Ontario, Canada N6A 5B7 (B.S.-M., A.G.I., N.P.A.H.); andDepartment of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, Ontario, Canada N6G 2V4 (P.P., G.L.)
| | - Gilles Lajoie
- Biology Department and Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Ontario, Canada N6A 5B7 (B.S.-M., A.G.I., N.P.A.H.); andDepartment of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, Ontario, Canada N6G 2V4 (P.P., G.L.)
| | - Norman P A Hüner
- Biology Department and Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, Ontario, Canada N6A 5B7 (B.S.-M., A.G.I., N.P.A.H.); andDepartment of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, Ontario, Canada N6G 2V4 (P.P., G.L.)
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Loran OB, Kogan MI, Sinjakova LA, Ivanov AG, Vinarov AZ, Spivak LG, Lokshin KL, Zajcev AV, Korsunskaja IL, Kapsargin FP, Hlebnovas EJ. [RATIONAL THERAPY FOR RECURRENT INFECTIONS OF THE LOWER URINARY TRACT. THE RESULTS OF A PROSPECTIVE OBSERVATIONAL PROGRAM TO ASSESS THE EFFECTIVENESS AND SAFETY OF CEFORAL®, SOLUTAB®* AND URO-VAKSOM® IN PATIENTS WITH RECURRENT UNCOMPLICATED LOWER URINARY TRACT INFECTIONS (FLORA)]. Urologiia 2015:12-18. [PMID: 26665758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Remaining generally unchanged, urinary tract infection (UTI) treatment protocols require continuing monitoring due to growing antibiotic resistance and lowered immune status of the majority of patients. The article presents the results of a prospective observational program carried out the Russian Federation in to assess the effectiveness and safety of Ceforal®, Solutab® and Uro-Vaksom® in patients with recurrent uncomplicated lower urinary tract infections (FLORA). The results of the program suggest that Ceforal® Solutab® and Uro-Vaksom® administered as a part of routine clinical practice contribute to a significant reduction in the number of UTI recurrences and have a good safety profile. These findings support recommendation to use this treatment protocol in patients with recurrent UTI, taking into account individual and epidemiological features.
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Chaudhury A, Ward C, Talasaz A, Ivanov AG, Huner NP, Grodzinski B, Patel RV, Barron JL. Computer Vision Based Autonomous Robotic System for 3D Plant Growth Measurement. 2015 12th Conference on Computer and Robot Vision 2015. [DOI: 10.1109/crv.2015.45] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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Farhat N, Ivanov AG, Krol M, Rabhi M, Smaoui A, Abdelly C, Hüner NPA. Preferential damaging effects of limited magnesium bioavailability on photosystem I in Sulla carnosa plants. Planta 2015; 241:1189-206. [PMID: 25637102 DOI: 10.1007/s00425-015-2248-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/17/2015] [Indexed: 05/03/2023]
Abstract
Magnesium deficiency preferentially inhibits photosystem I rather than photosystem II in Sulla carnosa plants. The effects of magnesium (Mg(2+)) deficiency on growth, photosynthetic performance, pigment and polypeptide composition of chloroplast membranes were studied in the halophyte Sulla carnosa (Desf.), an annual legume endemic to Tunisia and Algeria. The results demonstrate a gradual decrease in biomass production with decreasing Mg(2+) availability in the growth medium. The increase of Mg(2+) deficiency was also associated with a decline of the net CO2 assimilation (Pn) in fully expanded leaves, a decrease in the amount of photosynthetic pigments, and an increase in the lipid peroxidation in plants exposed to decreased Mg(2+) concentrations. Interestingly, while CO2 assimilation already was affected at Mg(2+) concentrations below 1.5 mM, the photochemical efficiency of photosystem II (PSII) declined only in the absence of Mg(2+). In contrast, plants of S. carnosa grown in Mg(2+)-deficient conditions exhibited a significant decrease in photosystem I (PSI) photochemistry in vivo at much higher Mg(2+) levels compared to PSII photochemical activity. The inhibitory effect of Mg(2+) deficiency on PSI photochemistry strongly correlated with significantly lower relative abundance of PSI-related chlorophyll-protein complexes and lower amounts of PSI-associated polypeptides, PsaA, PsaB, and Lhca proteins within the same range of Mg(2+) concentrations. These observations were associated with a higher intersystem electron pool size, restricted linear electron transport and a lower rate of reduction of P700(+) in the dark indicating restricted capacity for PSI cyclic electron transfer in plants exposed to Mg(2+)-deficient conditions compared to controls. These results clearly indicate that PSI, rather than PSII is preferentially targeted and damaged under Mg(2+)-deficiency conditions.
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Affiliation(s)
- Nèjia Farhat
- Laboratory of Extremophile Plants, Biotechnology Centre of Borj-Cedria, P. O. Box 901, 2050, Hammam-Lif, Tunisia
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Ivanov AG, Busheva MC, Velitchkova MY. Surface Charge Density Changes in Isolated Photosystem II Membranes Induced by Depletion of the Extrinsic Polypeptides of the Oxygen Evolving System. Z NATURFORSCH C 2014. [DOI: 10.1515/znc-1990-0611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Treatment of PS II particles with either 1 M NaCl or alkaline Tris (1 M , pH 8.4) caused a considerable decrease in the average net negative surface charge density, concomitant with depletion of the extrinsic 17, 24 and 33 kDa proteins of the oxygen evolving complex from the membranes. The partial recovery of the values for surface charge in both NaCl- and Tris-treated membranes was registered after reconstitution experiments with the three proteins. These results are compared with the data for the charge densities of the thylakoid membranes, to examine the role of the three extrinsic proteins in the formation of heterogeneous arrangement of surface charge across the appressed (granal) thylakoids.
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Affiliation(s)
- Alexander G. Ivanov
- Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113 Sofia, Bulgaria
| | - Mira C. Busheva
- Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113 Sofia, Bulgaria
| | - Maya Y. Velitchkova
- Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113 Sofia, Bulgaria
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Hüner NPA, Dahal K, Kurepin LV, Savitch L, Singh J, Ivanov AG, Kane K, Sarhan F. Potential for increased photosynthetic performance and crop productivity in response to climate change: role of CBFs and gibberellic acid. Front Chem 2014; 2:18. [PMID: 24860799 PMCID: PMC4029004 DOI: 10.3389/fchem.2014.00018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/25/2014] [Indexed: 01/07/2023] Open
Abstract
We propose that targeting the enhanced photosynthetic performance associated with the cold acclimation of winter cultivars of rye (Secale cereale L.), wheat (Triticum aestivum L.), and Brassica napus L. may provide a novel approach to improve crop productivity under abiotic as well as biotic stress conditions. In support of this hypothesis, we provide the physiological, biochemical, and molecular evidence that the dwarf phenotype induced by cold acclimation is coupled to significant enhancement in photosynthetic performance, resistance to photoinhibition, and a decreased dependence on photoprotection through non-photochemical quenching which result in enhanced biomass production and ultimately increased seed yield. These system-wide changes at the levels of phenotype, physiology, and biochemistry appear to be governed by the family of C-repeat/dehydration-responsive family of transcription factors (CBF/DREB1). We relate this phenomenon to the semi-dwarf, gibberellic acid insensitive (GAI), cereal varieties developed during the "green revolution" of the early 1960s and 1970s. We suggest that genetic manipulation of the family of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1) may provide a novel approach for the maintenance and perhaps even the enhancement of plant productivity under conditions of sub-optimal growth conditions predicted for our future climate.
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Affiliation(s)
- Norman P. A. Hüner
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western OntarioLondon, ON, Canada
| | - Keshav Dahal
- Department of Biological Sciences, University of Toronto at ScarboroughScarborough, ON, Canada
| | - Leonid V. Kurepin
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western OntarioLondon, ON, Canada
| | - Leonid Savitch
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food CanadaOttawa, ON, Canada
| | - Jas Singh
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food CanadaOttawa, ON, Canada
| | - Alexander G. Ivanov
- Biology Department and the Biotron Centre for Experimental Climate Change Research, University of Western OntarioLondon, ON, Canada
| | - Khalil Kane
- Départment des Sciences biologiques, Université du Québec à MontréalMontréal, QC, Canada
| | - Fathey Sarhan
- Départment des Sciences biologiques, Université du Québec à MontréalMontréal, QC, Canada
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Kurepin LV, Dahal KP, Savitch LV, Singh J, Bode R, Ivanov AG, Hurry V, Hüner NPA. Role of CBFs as integrators of chloroplast redox, phytochrome and plant hormone signaling during cold acclimation. Int J Mol Sci 2013; 14:12729-63. [PMID: 23778089 PMCID: PMC3709810 DOI: 10.3390/ijms140612729] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/24/2013] [Accepted: 06/06/2013] [Indexed: 11/16/2022] Open
Abstract
Cold acclimation of winter cereals and other winter hardy species is a prerequisite to increase subsequent freezing tolerance. Low temperatures upregulate the expression of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1) which in turn induce the expression of COLD-REGULATED (COR) genes. We summarize evidence which indicates that the integration of these interactions is responsible for the dwarf phenotype and enhanced photosynthetic performance associated with cold-acclimated and CBF-overexpressing plants. Plants overexpressing CBFs but grown at warm temperatures mimic the cold-tolerant, dwarf, compact phenotype; increased photosynthetic performance; and biomass accumulation typically associated with cold-acclimated plants. In this review, we propose a model whereby the cold acclimation signal is perceived by plants through an integration of low temperature and changes in light intensity, as well as changes in light quality. Such integration leads to the activation of the CBF-regulon and subsequent upregulation of COR gene and GA 2-oxidase (GA2ox) expression which results in a dwarf phenotype coupled with increased freezing tolerance and enhanced photosynthetic performance. We conclude that, due to their photoautotrophic nature, plants do not rely on a single low temperature sensor, but integrate changes in light intensity, light quality, and membrane viscosity in order to establish the cold-acclimated state. CBFs appear to act as master regulators of these interconnecting sensing/signaling pathways.
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Affiliation(s)
- Leonid V. Kurepin
- Department of Biology and the Biotron Center for Experimental Climate Change Research, Western University, London, ON N6A 5B7, Canada; E-Mails: (R.B.); (A.G.I.)
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå 901 87, Sweden; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (L.V.K.); (N.P.A.H.); Tel.: +1-519-661-2111 (ext. 86638) (L.V.K.); +1-519-661-2111 (ext. 86488) (N.P.A.H.); Fax: +1-519-850-2343(L.V.K. & N.P.A.H.)
| | - Keshav P. Dahal
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada; E-Mail:
| | - Leonid V. Savitch
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada; E-Mails: (L.V.S.); (J.S.)
| | - Jas Singh
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada; E-Mails: (L.V.S.); (J.S.)
| | - Rainer Bode
- Department of Biology and the Biotron Center for Experimental Climate Change Research, Western University, London, ON N6A 5B7, Canada; E-Mails: (R.B.); (A.G.I.)
| | - Alexander G. Ivanov
- Department of Biology and the Biotron Center for Experimental Climate Change Research, Western University, London, ON N6A 5B7, Canada; E-Mails: (R.B.); (A.G.I.)
| | - Vaughan Hurry
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå 901 87, Sweden; E-Mail:
| | - Norman P. A. Hüner
- Department of Biology and the Biotron Center for Experimental Climate Change Research, Western University, London, ON N6A 5B7, Canada; E-Mails: (R.B.); (A.G.I.)
- Authors to whom correspondence should be addressed; E-Mails: (L.V.K.); (N.P.A.H.); Tel.: +1-519-661-2111 (ext. 86638) (L.V.K.); +1-519-661-2111 (ext. 86488) (N.P.A.H.); Fax: +1-519-850-2343(L.V.K. & N.P.A.H.)
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Pischugina AV, Ivanov AG, Belyakova NA. [The characteristics of morbidity of workers of nuclear power engineering enterprise]. Probl Sotsialnoi Gig Zdravookhranenniiai Istor Med 2013:18-21. [PMID: 23672064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The article considers the morbidity endocrine, pathology included, of workers of nuclear power station and body-abled population of the district employed in other areas of professional activities. The statistically reliable exceeding of the level of primarily diagnosed endocrine morbidity in the group of working population of the district as compared with the group of workers of nuclear power station is established. In the compared groups, the structure of pathology of endocrine system is characterized by the prevalence of diseases of thyroid gland and obesity. The official statistics data reflects the level of morbidity of working population depending on appealability to curative preventive institutions, ratio and scope of the periodic medical examinations, availability of shop therapeutic service and possibility to involve physicians-specialists to health posts enterprises. Therefore, the foundation of enhancement of quality of medical care to workers is the improvemnent of organizational activities at the level of primary health care.
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Hüner NPA, Bode R, Dahal K, Hollis L, Rosso D, Krol M, Ivanov AG. Chloroplast redox imbalance governs phenotypic plasticity: the "grand design of photosynthesis" revisited. Front Plant Sci 2012; 3:255. [PMID: 23230444 PMCID: PMC3515967 DOI: 10.3389/fpls.2012.00255] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/30/2012] [Indexed: 05/03/2023]
Abstract
Sunlight, the ultimate energy source for life on our planet, enters the biosphere as a direct consequence of the evolution of photoautotrophy. Photoautotrophs must balance the light energy absorbed and trapped through extremely fast, temperature-insensitive photochemistry with energy consumed through much slower, temperature-dependent biochemistry and metabolism. The attainment of such a balance in cellular energy flow between chloroplasts, mitochondria and the cytosol is called photostasis. Photoautotrophs sense cellular energy imbalances through modulation of excitation pressure which is a measure of the relative redox state of Q(A), the first stable quinone electron acceptor of photosystem II reaction centers. High excitation pressure constitutes a potential stress condition that can be caused either by exposure to an irradiance that exceeds the capacity of C, N, and S assimilation to utilize the electrons generated from the absorbed energy or by low temperature or any stress that decreases the capacity of the metabolic pathways downstream of photochemistry to utilize photosynthetically generated reductants. The similarities and differences in the phenotypic responses between cyanobacteria, green algae, crop plants, and variegation mutants of Arabidopsis thaliana as a function of cold acclimation and photoacclimation are reconciled in terms of differential responses to excitation pressure and the predisposition of photoautotrophs to maintain photostasis. The various acclimation strategies associated with green algae and cyanobacteria versus winter cereals and A. thaliana are discussed in terms of retrograde regulation and the "grand design of photosynthesis" originally proposed by Arnon (1982).
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Affiliation(s)
- Norman P. A. Hüner
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
| | - Rainer Bode
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
| | - Keshav Dahal
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
| | - Lauren Hollis
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
| | - Dominic Rosso
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
| | - Marianna Krol
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
| | - Alexander G. Ivanov
- Department of Biology, Western UniversityLondon, ON, Canada
- The Biotron Centre for Experimental Climate Change Research, Western UniversityLondon, ON, Canada
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Ivanov AG, Rosso D, Savitch LV, Stachula P, Rosembert M, Oquist G, Hurry V, Hüner NPA. Implications of alternative electron sinks in increased resistance of PSII and PSI photochemistry to high light stress in cold-acclimated Arabidopsis thaliana. Photosynth Res 2012; 113:191-206. [PMID: 22843101 DOI: 10.1007/s11120-012-9769-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 07/11/2012] [Indexed: 05/06/2023]
Abstract
Exposure of control (non-hardened) Arabidopsis leaves to high light stress at 5 °C resulted in a decrease of both photosystem II (PSII) (45 %) and Photosystem I (PSI) (35 %) photochemical efficiencies compared to non-treated plants. In contrast, cold-acclimated (CA) leaves exhibited only 35 and 22 % decrease of PSII and PSI photochemistry, respectively, under the same conditions. This was accompanied by an accelerated rate of P700(+) re-reduction, indicating an up-regulation of PSI-dependent cyclic electron transport (CET). Interestingly, the expression of the NDH-H gene and the relative abundance of the Ndh-H polypeptide, representing the NDH-complex, decreased as a result of exposure to low temperatures. This indicates that the NDH-dependent CET pathway cannot be involved and the overall stimulation of CET in CA plants is due to up-regulation of the ferredoxin-plastoquinone reductase, antimycin A-sensitive CET pathway. The lower abundance of NDH complex also implies lower activity of the chlororespiratory pathway in CA plants, although the expression level and overall abundance of the other well-characterized component involved in chlororespiration, the plastid terminal oxidase (PTOX), was up-regulated at low temperatures. This suggests increased PTOX-mediated alternative electron flow to oxygen in plants exposed to low temperatures. Indeed, the estimated proportion of O(2)-dependent linear electron transport not utilized in carbon assimilation and not directed to photorespiration was twofold higher in CA Arabidopsis. The possible involvement of alternative electron transport pathways in inducing greater resistance of both PSII and PSI to high light stress in CA plants is discussed.
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Affiliation(s)
- A G Ivanov
- Department of Biology, Western University, 1151 Richmond Street N., London, ON, N6A 5B7, Canada.
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Ivanov AG, Allakhverdiev SI, Huner NPA, Murata N. Genetic decrease in fatty acid unsaturation of phosphatidylglycerol increased photoinhibition of photosystem I at low temperature in tobacco leaves. Biochim Biophys Acta 2012; 1817:1374-9. [PMID: 22445720 DOI: 10.1016/j.bbabio.2012.03.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/02/2012] [Accepted: 03/07/2012] [Indexed: 11/28/2022]
Abstract
Leaves of transgenic tobacco plants with decreased levels of fatty acid unsaturation in phosphatidylglycerol (PG) exhibited a slightly lower level of the steady state oxidation of the photosystem I (PSI) reaction center P700 (P700(+)) than wild-type plants. The PSI photochemistry of wild-type plants was only marginally affected by high light treatments. Surprisingly, all plants of transgenic lines exhibited much higher susceptibility to photoinhibition of PSI than wild-type plants. This was accompanied by a 2.5-fold faster re-reduction rate of P700(+) in the dark, indicating a higher capacity for cyclic electron flow around PSI in high light treated transgenic leaves. This was associated with a much higher intersystem electron pool size suggesting over-reduction of the PQ pool in tobacco transgenic lines with altered PG unsaturation compared to wild-type plants. The physiological role of PG unsaturation in PSI down-regulation and modulation of the capacity of PSI-dependent cyclic electron flows and distribution of excitation light energy in tobacco plants under photoinhibitory conditions at low temperatures is discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- A G Ivanov
- Department of Biology, University of Western Ontario, London, Ontario, Canada.
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Ivanov AG, Sane PV, Simidjiev I, Park YI, Huner NPA, Oquist G. Restricted capacity for PSI-dependent cyclic electron flow in ΔpetE mutant compromises the ability for acclimation to iron stress in Synechococcus sp. PCC 7942 cells. Biochim Biophys Acta 2012; 1817:1277-84. [PMID: 22465025 DOI: 10.1016/j.bbabio.2012.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/28/2012] [Accepted: 03/12/2012] [Indexed: 10/28/2022]
Abstract
Exposure of wild type (WT) and plastocyanin coding petE gene deficient mutant (ΔpetE) of Synechococcus cells to low iron growth conditions was accompanied by similar iron-stress induced blue-shift of the main red Chl a absorption peak and a gradual decrease of the Phc/Chl ratio, although ΔpetE mutant was more sensitive when exposed to iron deficient conditions. Despite comparable iron stress induced phenotypic changes, the inactivation of petE gene expression was accompanied with a significant reduction of the growth rates compared to WT cells. To examine the photosynthetic electron fluxes in vivo, far-red light induced P700 redox state transients at 820nm of WT and ΔpetE mutant cells grown under iron sufficient and iron deficient conditions were compared. The extent of the absorbance change (ΔA(820)/A(820)) used for quantitative estimation of photooxidizable P700(+) indicated a 2-fold lower level of P700(+) in ΔpetE compared to WT cells under control conditions. This was accompanied by a 2-fold slower re-reduction rate of P700(+) in the ΔpetE indicating a lower capacity for cyclic electron flow around PSI in the cells lacking plastocyanin. Thermoluminescence (TL) measurements did not reveal significant differences in PSII photochemistry between control WT and ΔpetE cells. However, exposure to iron stress induced a 4.5 times lower level of P700(+), 2-fold faster re-reduction rate of P700(+) and a temperature shift of the TL peak corresponding to S(2)/S(3)Q(B)(-) charge recombination in WT cells. In contrast, the iron-stressed ΔpetE mutant exhibited only a 40% decrease of P700(+) and no significant temperature shift in S(2)/S(3)Q(B)(-) charge recombination. The role of mobile electron carriers in modulating the photosynthetic electron fluxes and physiological acclimation of cyanobacteria to low iron conditions is discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- A G Ivanov
- Department of Biology, University of Western Ontario, London, ON, Canada
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Savitch LV, Ivanov AG, Gudynaite-Savitch L, Huner NPA, Simmonds J. Cold Stress Effects on PSI Photochemistry in Zea mays: Differential Increase of FQR-Dependent Cyclic Electron Flow and Functional Implications. ACTA ACUST UNITED AC 2011; 52:1042-54. [DOI: 10.1093/pcp/pcr056] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Savitch LV, Ivanov AG, Krol M, Sprott DP, Oquist G, Huner NPA. Regulation of energy partitioning and alternative electron transport pathways during cold acclimation of lodgepole pine is oxygen dependent. Plant Cell Physiol 2010; 51:1555-70. [PMID: 20630988 DOI: 10.1093/pcp/pcq101] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Second year needles of Lodgepole pine (Pinus contorta L.) were exposed for 6 weeks to either simulated control summer ['summer'; 25 °C/250 photon flux denisty (PFD)], autumn ('autumn'; 15°C/250 PFD) or winter conditions ('winter'; 5 °C/250 PFD). We report that the proportion of linear electron transport utilized in carbon assimilation (ETR(CO2)) was 40% lower in both 'autumn' and 'winter' pine when compared with the 'summer' pine. In contrast, the proportion of excess photosynthetic linear electron transport (ETR(excess)) not used for carbon assimilation within the total ETR(Jf) increased by 30% in both 'autumn' and 'winter' pine. In 'autumn' pine acclimated to 15°C, the increased amounts of 'excess' electrons were directed equally to 21 kPa O2-dependent and 2 kPa O2-dependent alternative electron transport pathways and the fractions of excitation light energy utilized by PSII photochemistry (Φ(PSII)), thermally dissipated through Φ(NPQ) and dissipated by additional quenching mechanism(s) (Φ(f,D)) were similar to those in 'summer' pine. In contrast, in 'winter' needles acclimated to 5 °C, 60% of photosynthetically generated 'excess' electrons were utilized through the 2 kPa O2-dependent electron sink and only 15% by the photorespiratory (21 kPa O2) electron pathway. Needles exposed to 'winter' conditions led to a 3-fold lower Φ(PSII), only a marginal increase in Φ(NPQ) and a 2-fold higher Φ(f,D), which was O2 dependent compared with the 'summer' and 'autumn' pine. Our results demonstrate that the employment of a variety of alternative pathways for utilization of photosynthetically generated electrons by Lodgepole pine depends on the acclimation temperature. Furthermore, dissipation of excess light energy through constitutive non-photochemical quenching mechanisms is O2 dependent.
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Affiliation(s)
- Leonid V Savitch
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, Ottawa, ON K1A0C6, Canada.
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Krol M, Ivanov AG, Booij-James I, Mattoo AK, Sane PV, Hüner NP. Absence of the major light-harvesting antenna proteins alters the redox properties of photosystem II reaction centres in thechlorina F2mutant of barley. Biochem Cell Biol 2009; 87:557-66. [DOI: 10.1139/o09-013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although the chlorina F2 mutant of barley specifically exhibits reduced levels of the major light-harvesting polypeptides associated with photosystem II (PSII), thermoluminescence measurements of photosystem reaction centre photochemistry revealed that S2/S3QB–charge recombinations were shifted to lower temperatures, while the characteristic peak of S2QA–charge recombinations was shifted to higher temperatures compared with wild-type (WT) barley. Thus, we show that the absence of the major light-harvesting polypeptides affects the redox properties of PSII reaction centres. Radiolabeling studies in vivo and in vitro with [32P]orthophosphate or [γ-32P]ATP, respectively, demonstrated that the D1 PSII reaction centre polypeptide is phosphorylated in both the WT and the F2 mutant. In contrast with the radiolabeling results, phosphorylation of D1 and other PSII proteins, although detected in WT barley, was ambiguous in the F2 mutant when the phosphothreonine antibody method of detection was used. Thus, caution must be exercised in the use of commercially available phosphothreonine antibodies to estimate thylakoid polypeptide phosphorylation. Furthermore, in membrano, the D1 polypeptide of the F2 mutant was less susceptible to trypsin treatment than that of WT barley. The role of the light-harvesting complex in modulating the structure and function of the D1 polypeptide of PSII reaction centers is discussed.
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Affiliation(s)
- Marianna Krol
- Department of Biology and the Biotron Experimental Climate Change Research Centre, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada
- Henry A. Wallace Beltsville Agricultural Research Center, USDA/ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
| | - Alexander G. Ivanov
- Department of Biology and the Biotron Experimental Climate Change Research Centre, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada
- Henry A. Wallace Beltsville Agricultural Research Center, USDA/ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
| | - Isabelle Booij-James
- Department of Biology and the Biotron Experimental Climate Change Research Centre, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada
- Henry A. Wallace Beltsville Agricultural Research Center, USDA/ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
| | - Autar K. Mattoo
- Department of Biology and the Biotron Experimental Climate Change Research Centre, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada
- Henry A. Wallace Beltsville Agricultural Research Center, USDA/ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
| | - P. V. Sane
- Department of Biology and the Biotron Experimental Climate Change Research Centre, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada
- Henry A. Wallace Beltsville Agricultural Research Center, USDA/ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
| | - Norman P.A. Hüner
- Department of Biology and the Biotron Experimental Climate Change Research Centre, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada
- Henry A. Wallace Beltsville Agricultural Research Center, USDA/ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
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Reyes-Díaz M, Ivanov AG, Huner NPA, Alberdi M, Corcuera LJ, Bravo LA. Thermal energy dissipation and its components in two developmental stages of a shade-tolerant species, Nothofagus nitida, and a shade-intolerant species, Nothofagus dombeyi. Tree Physiol 2009; 29:651-662. [PMID: 19203980 DOI: 10.1093/treephys/tpp003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nothofagus dombeyi (Mirb.) Blume and Nothofagus nitida (Phil.) Krasser, two evergreens in the South Chilean forest, regenerate in open habitats and under the canopy, respectively. Both overtop the forest canopy when they are in the adult stage, suggesting that their photoprotective mechanisms differ in ontogenetic dynamics. We postulated that N. nitida, a shade-tolerant species increases its capacity to tolerate photoinhibitory conditions (low temperature and high irradiance) by thermal energy dissipation of excess energy during its transition from the seedling to the adult stage, whereas N. dombeyi, a shade-intolerant species, maintains a high capacity for photoprotection by thermal energy dissipation from the seedling to the adult stage. To test this hypothesis, the main photoprotective mechanisms in plants - the fast- and slow-relaxing components of thermal energy dissipation (NPQ, non-photochemical quenching) NPQ(F) and NPQ(S), respectively, and state transitions - were studied in seedlings and adults of both species grown in their natural habitats and in a common garden. In adults, NPQ(F) and NPQ(S) did not differ between species and seasons. The greatest differences in these parameters were observed in seedlings. The xanthophyll cycle was more active in N. dombeyi seedlings than in N. nitida seedlings at low temperature and high irradiance, consistent with a higher NPQ(F) in N. dombeyi. Under all study conditions, N. nitida seedlings had higher NPQ(S) than N. dombeyi seedlings. The state transition capability was higher in N. nitida seedlings than in N. dombeyi seedlings. Therefore, although (shade-intolerant) N. dombeyi was able to thermally dissipate the excess absorbed energy, under natural conditions its photochemical energy quenching was efficient in both developmental stages, decreasing its need for thermal dissipation. In contrast, the seedlings of N. nitida were more sensitive to photoinhibition than the adult trees, suggesting a change from shade-grown to sun-exposed phenotype from the seedling to the adult stage. These results help to explain the differences in the regeneration patterns of N. nitida and N. dombeyi and the presence of N. nitida adult stage in the upper canopy.
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Affiliation(s)
- Marjorie Reyes-Díaz
- Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile
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Savitch LV, Ivanov AG, Gudynaite-Savitch L, Huner NPA, Simmonds J. Effects of low temperature stress on excitation energy partitioning and photoprotection in Zea mays. Funct Plant Biol 2009; 36:37-49. [PMID: 32688625 DOI: 10.1071/fp08093] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Accepted: 10/04/2008] [Indexed: 05/08/2023]
Abstract
Analysis of the partitioning of absorbed light energy within PSII into fractions utilised by PSII photochemistry (ΦPSII), thermally dissipated via ΔpH- and zeaxanthin-dependent energy quenching (ΦNPQ) and constitutive non-photochemical energy losses (Φf,D) was performed in control and cold-stressed maize (Zea mays L.) leaves. The estimated energy partitioning of absorbed light to various pathways indicated that the fraction of ΦPSII was twofold lower, whereas the proportion of thermally dissipated energy through ΦNPQ was only 30% higher, in cold-stressed plants compared with control plants. In contrast, Φf,D, the fraction of absorbed light energy dissipated by additional quenching mechanism(s), was twofold higher in cold-stressed leaves. Thermoluminescence measurements revealed that the changes in energy partitioning were accompanied by narrowing of the temperature gap (ΔTM) between S2/3QB- and S2QA- charge recombinations in cold-stressed leaves to 8°C compared with 14.4°C in control maize plants. These observations suggest an increased probability for an alternative non-radiative P680+QA- radical pair recombination pathway for energy dissipation within the reaction centre of PSII in cold-stressed maize plants. This additional quenching mechanism might play an important role in thermal energy dissipation and photoprotection when the capacity for the primary, photochemical (ΦPSII) and zeaxanthin-dependent non-photochemical quenching (ΦNPQ) pathways are thermodynamically restricted in maize leaves exposed to cold temperatures.
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Affiliation(s)
- Leonid V Savitch
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre (ECORC), Central Experimental Farm, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | | | - Norman P A Huner
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - John Simmonds
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre (ECORC), Central Experimental Farm, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
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Ivanov AG, Sane PV, Hurry V, Oquist G, Huner NPA. Photosystem II reaction centre quenching: mechanisms and physiological role. Photosynth Res 2008; 98:565-74. [PMID: 18821028 DOI: 10.1007/s11120-008-9365-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2008] [Accepted: 09/01/2008] [Indexed: 05/03/2023]
Abstract
Dissipation of excess absorbed light energy in eukaryotic photoautotrophs through zeaxanthin- and DeltapH-dependent photosystem II antenna quenching is considered the major mechanism for non-photochemical quenching and photoprotection. However, there is mounting evidence of a zeaxanthin-independent pathway for dissipation of excess light energy based within the PSII reaction centre that may also play a significant role in photoprotection. We summarize recent reports which indicate that this enigma can be explained, in part, by the fact that PSII reaction centres can be reversibly interconverted from photochemical energy transducers that convert light into ATP and NADPH to efficient, non-photochemical energy quenchers that protect the photosynthetic apparatus from photodamage. In our opinion, reaction centre quenching complements photoprotection through antenna quenching, and dynamic regulation of photosystem II reaction centre represents a general response to any environmental condition that predisposes the accumulation of reduced Q(A) in the photosystem II reaction centres of prokaryotic and eukaryotic photoautotrophs. Since the evolution of reaction centres preceded the evolution of light harvesting systems, reaction centre quenching may represent the oldest photoprotective mechanism.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology and The Biotron, University of Western Ontario, London, ON, Canada
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Morgan-Kiss RM, Ivanov AG, Modla S, Czymmek K, Hüner NPA, Priscu JC, Lisle JT, Hanson TE. Identity and physiology of a new psychrophilic eukaryotic green alga, Chlorella sp., strain BI, isolated from a transitory pond near Bratina Island, Antarctica. Extremophiles 2008; 12:701-11. [DOI: 10.1007/s00792-008-0176-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Accepted: 06/04/2008] [Indexed: 11/30/2022]
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Ivanov AG, Trusov VV. [Optimization of therapy in patients with hepatic cirrhosis and encephalopathy]. Klin Med (Mosk) 2008; 86:62-66. [PMID: 18720715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
With the aim of optimization of therapy of hepatic cirrhosis with manifestations of system encephalopathy 45 patients were examined. The patients were divided into 2 groups: control group (20 patients who received traditional therapy) and observing group (25 patients who in addition to traditional therapy received cryoapheresis). Clinical symptoms, results of neuropsychological and paraclinical examination, and indices of dynamic hepatobiliscintigraphy against the background of various methods of therapy were studied. It was established that with the use of pathogenetic therapy of hepatic encephalopathy--cryoapheresis--processes of hepatic encephalopathy progressing significantly decelerated, which made possible to approach to the choice of therapy individually, and, thereby, to optimize treatment.
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44
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45
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46
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Ivanov AG, Krol M, Selstam E, Sane PV, Sveshnikov D, Park YI, Oquist G, Huner NPA. The induction of CP43′ by iron-stress in Synechococcus sp. PCC 7942 is associated with carotenoid accumulation and enhanced fatty acid unsaturation. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2007; 1767:807-13. [PMID: 17362874 DOI: 10.1016/j.bbabio.2007.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 02/05/2007] [Accepted: 02/06/2007] [Indexed: 10/23/2022]
Abstract
Comparative lipid analysis demonstrated reduced amount of PG (50%) and lower ratio of MGDG/DGDG in iron-stressed Synechococcus sp. PCC 7942 cells compared to cells grown under iron sufficient conditions. In parallel, the monoenoic (C:1) fatty acids in MGDG, DGDG and PG increased from 46.8%, 43.7% and 45.6%, respectively in control cells to 51.6%, 48.8% and 48.7%, respectively in iron-stressed cells. This suggests increased membrane dynamics, which may facilitate the diffusion of PQ and keep the PQ pool in relatively more oxidized state in iron-stressed compared to control cells. This was confirmed by chlorophyll fluorescence and thermoluminescence measurements. Analysis of carotenoid composition demonstrated that the induction of isiA (CP43') protein in response to iron stress is accompanied by significant increase of the relative abundance of all carotenoids. The quantity of carotenoids calculated on a Chl basis increased differentially with nostoxanthin, cryptoxanthin, zeaxanthin and beta-carotene showing 2.6-, 3.1-, 1.9- and 1.9-fold increases, respectively, while the relative amount of caloxanthin was increased only by 30%. HPLC analyses of the pigment composition of Chl-protein complexes separated by non-denaturating SDS-PAGE demonstrated even higher relative carotenoids content, especially of cryptoxanthin, in trimer and monomer PSI Chl-protein complexes co-migrating with CP43' from iron-stressed cells than in PSI complexes from control cells where CP43' is not present. This implies a carotenoid-binding role for the CP43' protein which supports our previous suggestion for effective energy quenching and photoprotective role of CP43' protein in cyanobacteria under iron stress.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology and The Biotron, University of Western Ontario, 1151 Richmond Street N., London, Ontario, Canada
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Ivanov AG. [Analysis of clonidine in biological fluids using gas chromatography with an electron capture detector]. Sud Med Ekspert 2007; 50:28-30. [PMID: 17598446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The method of clonidine identification in blood and urine is described. It is based on liquid-liquid extraction and purification with toluol, subsequent derivation with pentafluobenzoylchloride and test on gas chromatograph with a detector of electron capture. The method is proposed for expert examinations.
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Ivanov AG, Miskiewicz E, Clarke AK, Greenberg BM, Huner NPA. Protection of Photosystem II Against UV-A and UV-B Radiation in the Cyanobacterium Plectonema boryanum: The Role of Growth Temperature and Growth Irradiance¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0720772popiau2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bravo LA, Saavedra-Mella FA, Vera F, Guerra A, Cavieres LA, Ivanov AG, Huner NPA, Corcuera LJ. Effect of cold acclimation on the photosynthetic performance of two ecotypes of Colobanthus quitensis (Kunth) Bartl. J Exp Bot 2007; 58:3581-90. [PMID: 18057038 DOI: 10.1093/jxb/erm206] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The effects of cold acclimation of two ecotypes (Antarctic and Andes) of Colobanthus quitensis (Kunth) Bartl. Caryophyllaceae on their photosynthetic characteristics and performance under high light (HL) were compared. Non-acclimated plants of the Antarctic ecotype exhibited a higher (34%) maximal rate of photosynthesis than the Andes ecotype. In cold-acclimated plants the light compensation point was increased. Dark respiration was significantly increased during the exposure to 4 degrees C in both ecotypes. Cold-acclimated Antarctic plants showed higher Phi(PSII) and qP compared with the Andes ecotype. In addition, the Antarctic ecotype exhibited higher heat dissipation (NPQ), especially in the cold-acclimated state, which was mainly associated with the fast relaxing component of non-photochemical quenching (NPQ(F)). By contrast, the Andes ecotype exhibited a lower NPQ(F) and a significant increase in the slowly relaxing component (NPQ(s)) at low temperature and HL, indicating higher sensitivity to low temperature-induced photoinhibition. Although the xanthophyll cycle was fully operational in both ecotypes, cold-acclimated Antarctic plants exposed to HL exhibited higher epoxidation state of the xanthophyll cycle pigments (EPS) compared with the cold-acclimated Andes ecotype. Thus, the photosynthetic apparatus of the Antarctic ecotype operates more efficiently than that of the Andes one, under a combination of low temperature and HL. The ecotype differences are discussed in relation to the different climatic conditions of the two Colobanthus.
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Affiliation(s)
- León A Bravo
- Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Correo 3, Concepción, Chile.
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Szyszka B, Ivanov AG, Hüner NPA. Psychrophily is associated with differential energy partitioning, photosystem stoichiometry and polypeptide phosphorylation in Chlamydomonas raudensis. Biochim Biophys Acta 2006; 1767:789-800. [PMID: 17234152 DOI: 10.1016/j.bbabio.2006.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 11/23/2006] [Accepted: 12/03/2006] [Indexed: 11/29/2022]
Abstract
Chlamydomonas raudensis UWO 241 and SAG 49.72 represent the psychrophilic and mesophilic strains of this green algal species. This novel discovery was exploited to assess the role of psychrophily in photoacclimation to growth temperature and growth irradiance. At their optimal growth temperatures of 8 degrees C and 28 degrees C respectively, UWO 241 and SAG 49.72 maintained comparable photostasis, that is energy balance, as measured by PSII excitation pressure. Although UWO 241 exhibited higher excitation pressure, measured as 1-qL, at all growth light intensities, the relative changes in 1-qL were similar to that of SAG 49.72 in response to growth light. In response to suboptimal temperatures and increased growth irradiance, SAG 49.72 favoured energy partitioning of excess excitation energy through inducible, down regulatory processes (Phi(NPQ)) associated with the xanthophyll cycle and antenna quenching, while UWO 241 favoured xanthophyll cycle-independent energy partitioning through constitutive processes involved in energy dissipation (Phi(NO)). In contrast to SAG 49.72, an elevation in growth temperature induced an increase in PSI/PSII stoichiometry in UWO 241. Furthermore, SAG 49.72 showed typical threonine-phosphorylation of LHCII, whereas UWO 241 exhibited phosphorylation of polypeptides of comparable molecular mass to PSI reaction centres but the absence of LHCII phosphorylation. Thus, although both strains maintain an energy balance irrespective of their differences in optimal growth temperatures, the mechanisms used to maintain photostasis were distinct. We conclude that psychrophily in C. raudensis is complex and appears to involve differential energy partitioning, photosystem stoichiometry and polypeptide phosphorylation.
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Affiliation(s)
- Beth Szyszka
- Department of Biology and The Biotron, University of Western Ontario, 1151 Richmond Street N., London, Ontario, Canada
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