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Zarmi Y. High-intensity pulsed-light cultivation of unicellular algae: Photosynthesis continues in the dark. Heliyon 2024; 10:e27224. [PMID: 38495149 PMCID: PMC10943342 DOI: 10.1016/j.heliyon.2024.e27224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/15/2023] [Accepted: 02/26/2024] [Indexed: 03/19/2024] Open
Abstract
Experiments have shown that photon exploitation efficiency in unicellular algal biomass production under a pulsed-light regime with a high-photon flux is higher than the efficiency under continuous illumination with the same flux. This observation has been explained theoretically to be a consequence of the improved efficiency of exploitation of photons by Photosystem II (PS II) thanks to the combined effect of photon-absorption statistics, a rate-limiting time scale and the size of the PQ pool. Exploiting the same ideas, it is shown in this paper that, under a pulsed-light regime, there is a pulse-time length, for which the average exploitation efficiency of PS II absorbed photons is maximal. Under ideal conditions, this maximum is close to 100%. The optimal pulse-time length is roughly proportional to the size of the PQ pool, NPQ. This is clearly seen for τ (the average time gap between consecutive photons absorbed by the PS II-Chlorophyll antenna) of the order of 1 ms or less (corresponding to a high photon flux and/or a large photon absorption cross-section area of the antenna) and for small NPQ. The width of the plot of efficiency vs. pulse length around the optimum is then small and the optimal pulse length is well defined. As τ is increased beyond 1 or NPQ becomes large, the width grows, allowing for a broad choice of pulse lengths, for which efficiency is very close to the maximum. These observations open the door to future designs of highly productive bioreactors.
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Affiliation(s)
- Yair Zarmi
- Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 8499000, Israel
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Plyusnina TY, Khruschev SS, Degtereva NS, Voronova EN, Volgusheva AA, Riznichenko GY, Rubin AB. Three-state mathematical model for the assessment of DCMU-treated photosystem II heterogeneity. PHOTOSYNTHESIS RESEARCH 2024; 159:303-320. [PMID: 38466456 DOI: 10.1007/s11120-024-01077-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 01/15/2024] [Indexed: 03/13/2024]
Abstract
Photosystem II (PSII) is one of the main pigment-protein complexes of photosynthesis which is highly sensitive to unfavorable environmental factors. The heterogeneity of PSII properties is essential for the resistance of autotrophic organisms to stress factors. Assessment of the PSII heterogeneity may be used in environmental monitoring for on-line detection of contamination of the environment. We propose an approach to assess PSII oxygen-evolving complex and light-harvesting antenna heterogeneity that is based on mathematical modeling of the shape of chlorophyll a fluorescence rise of 3-(3,4-dichlorophenyl)-1,1-dimethylurea-treated samples. The hierarchy of characteristic times of the processes considered in the model makes it possible to reduce the model to a system of three ordinary differential equations. The analytic solution of the reduced three-state model is expressed as a sum of two exponential functions, and it exactly reproduces the solution of the complete system within the time range from microseconds to hundreds of milliseconds. The combination of several such models for reaction centers with different properties made it possible to use it as an instrument to study PSII heterogeneity. PSII heterogeneity was studied for Chlamydomonas at different intensities of actinic light, for Scenedesmus under short-term heating, and for Chlorella grown in nitrate-enriched and nitrate-depleted media.
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Affiliation(s)
- Tatiana Yu Plyusnina
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - Sergei S Khruschev
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Natalia S Degtereva
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Elena N Voronova
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alena A Volgusheva
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Galina Yu Riznichenko
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Andrew B Rubin
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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Smythers AL, Crislip JR, Slone DR, Flinn BB, Chaffins JE, Camp KA, McFeeley EW, Kolling DRJ. Excess manganese increases photosynthetic activity via enhanced reducing center and antenna plasticity in Chlorella vulgaris. Sci Rep 2023; 13:11301. [PMID: 37438371 DOI: 10.1038/s41598-023-35895-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 05/25/2023] [Indexed: 07/14/2023] Open
Abstract
Photosynthesis relies on many easily oxidizable/reducible transition metals found in the metalloenzymes that make up much of the photosynthetic electron transport chain (ETC). One of these is manganese, an essential cofactor of photosystem II (PSII) and a component of the oxygen-evolving complex, the only biological entity capable of oxidizing water. Additionally, manganese is a cofactor in enzymatic antioxidants, notably the superoxide dismutases-which are localized to the chloroplastic membrane. However, unlike other metals found in the photosynthetic ETC, previous research has shown exposure to excess manganese enhances photosynthetic activity rather than diminishing it. In this study, the impact of PSII heterogeneity on overall performance was investigated using chlorophyll fluorescence, a rapid, non-invasive technique that probed for overall photosynthetic efficiency, reducing site activity, and antenna size and distribution. These measurements unveiled an enhanced plasticity of PSII following excess manganese exposure, in which overall performance and reducing center activity increased while antenna size and proportion of PSIIβ centers decreased. This enhanced activity suggests manganese may hold the key to improving photosynthetic efficiency beyond that which is observed in nature.
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Affiliation(s)
- Amanda L Smythers
- Department of Chemistry, Marshall University, Huntington, WV, USA
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Danielle R Slone
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Brendin B Flinn
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | | | - Kristen A Camp
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Eli W McFeeley
- Department of Chemistry, Marshall University, Huntington, WV, USA
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Zarmi Y. Photon statistics and pulsed-light regime in experiments on unicellular algae. Heliyon 2022; 8:e12474. [PMID: 36590479 PMCID: PMC9801126 DOI: 10.1016/j.heliyon.2022.e12474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/09/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Photon arrival time statistics significantly affect the performance of the photosynthetic system under a pulsed-light regime when the average number of photons hitting the Chlorophyll antenna of PS II is small. As a result, the interpretation of measurements of the production rate of biomass or other products of unicellular algae under a pulsed-light regime and the comparison of the results with those obtained under continuous illumination depends crucially upon accounting for these statistics.
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Affiliation(s)
- Yair Zarmi
- Jacob Blaustein Institutes for Desert Research, Israel,Ben-Gurion University of the Negev, Israel,Midreshet Ben-Gurion, 8499000, Israel,Corresponding author.
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Wen X, Yang Z, Ding S, Yang H, Zhang L, Lu C, Lu Q. Analysis of the changes of electron transfer and heterogeneity of photosystem II in Deg1-reduced Arabidopsis plants. PHOTOSYNTHESIS RESEARCH 2021; 150:159-177. [PMID: 33993381 DOI: 10.1007/s11120-021-00842-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/04/2021] [Indexed: 05/07/2023]
Abstract
Deg1 protease functions in protease and chaperone of PSII complex components, but few works were performed to study the effects of Deg1 on electron transport activities on the donor and acceptor side of PSII and its correlation with the photoprotection of PSII during photoinhibition. Therefore, we performed systematic and comprehensive investigations of electron transfers on the donor and acceptor sides of photosystem II (PSII) in the Deg1-reduced transgenic lines deg1-2 and deg1-4. Both the maximal quantum efficiency of PSII photochemistry (Fv/Fm) and the actual PSII efficiency (ΦPSII) decreased significantly in the transgenic plants. Increases in nonphotochemical quenching (NPQ) and the dissipated energy flux per reaction center (DI0/RC) were also shown in the transgenic plants. Along with the decreased D1, CP47, and CP43 content, these results suggested photoinhibition under growth light conditions in transgenic plants. Decreased Deg1 caused inhibition of electron transfer on the PSII reducing side, leading to a decline in the number of QB-reducing centers and accumulation of QB-nonreducing centers. The Tm of the Q band shifted from 5.7 °C in the wild-type plant to 10.4 °C and 14.2 °C in the deg1-2 and deg1-4 plants, respectively, indicating an increase in the stability of S2QA¯ in transgenic plants. PSIIα in the transgenic plants largely reduced, while PSIIβ and PSIIγ increased with the decline in the Deg1 levels in transgenic plants suggesting PSIIα centers gradually converted into PSIIβ and PSIIγ centers in the transgenic plants. Besides, the connectivity of PSIIα and PSIIβ was downregulated in transgenic plants. Our results reveal that downregulation of Deg1 protein levels induced photoinhibition in transgenic plants, leading to loss of PSII activities on both the donor and acceptor sides in transgenic plants. These results give a new insight into the regulation role of Deg1 in PSII electron transport.
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Affiliation(s)
- Xiaogang Wen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100093, China
| | - Zhipan Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Shunhua Ding
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Huixia Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, 85 Minglun Street, Kaifeng, 475001, China
| | - Congming Lu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018, China.
| | - Qingtao Lu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
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Guardini Z, Dall’Osto L, Barera S, Jaberi M, Cazzaniga S, Vitulo N, Bassi R. High Carotenoid Mutants of Chlorella vulgaris Show Enhanced Biomass Yield under High Irradiance. PLANTS 2021; 10:plants10050911. [PMID: 34062906 PMCID: PMC8147269 DOI: 10.3390/plants10050911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022]
Abstract
Microalgae represent a carbon-neutral source of bulk biomass, for extraction of high-value compounds and production of renewable fuels. Due to their high metabolic activity and reproduction rates, species of the genus Chlorella are highly productive when cultivated in photobioreactors. However, wild-type strains show biological limitations making algal bioproducts expensive compared to those extracted from other feedstocks. Such constraints include inhomogeneous light distribution due to high optical density of the culture, and photoinhibition of the surface-exposed cells. Thus, the domestication of algal strains for industry makes it increasingly important to select traits aimed at enhancing light-use efficiency while withstanding excess light stress. Carotenoids have a crucial role in protecting against photooxidative damage and, thus, represent a promising target for algal domestication. We applied chemical mutagenesis to Chlorella vulgaris and selected for enhanced tolerance to the carotenoid biosynthesis inhibitor norflurazon. The NFR (norflurazon-resistant) strains showed an increased carotenoid pool size and enhanced tolerance towards photooxidative stress. Growth under excess light revealed an improved carbon assimilation rate of NFR strains with respect to WT. We conclude that domestication of Chlorella vulgaris, by optimizing both carotenoid/chlorophyll ratio and resistance to photooxidative stress, boosted light-to-biomass conversion efficiency under high light conditions typical of photobioreactors. Comparison with strains previously reported for enhanced tolerance to singlet oxygen, reveals that ROS resistance in Chlorella is promoted by at least two independent mechanisms, only one of which is carotenoid-dependent.
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Markou G, Dao LH, Muylaert K, Beardall J. Influence of different degrees of N limitation on photosystem II performance and heterogeneity of Chlorella vulgaris. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.07.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Effects of lead on two green microalgae Chlorella and Scenedesmus: photosystem II activity and heterogeneity. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.03.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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de Marchin T, Erpicum M, Franck F. Photosynthesis of Scenedesmus obliquus in outdoor open thin-layer cascade system in high and low CO2 in Belgium. J Biotechnol 2015; 215:2-12. [DOI: 10.1016/j.jbiotec.2015.06.429] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 06/20/2015] [Accepted: 06/25/2015] [Indexed: 12/24/2022]
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Derks A, Schaven K, Bruce D. Diverse mechanisms for photoprotection in photosynthesis. Dynamic regulation of photosystem II excitation in response to rapid environmental change. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:468-485. [DOI: 10.1016/j.bbabio.2015.02.008] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/03/2015] [Accepted: 02/07/2015] [Indexed: 12/26/2022]
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Pierangelini M, Stojkovic S, Orr PT, Beardall J. Elevated CO2 causes changes in the photosynthetic apparatus of a toxic cyanobacterium, Cylindrospermopsis raciborskii. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:1091-1098. [PMID: 24878143 DOI: 10.1016/j.jplph.2014.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Revised: 04/11/2014] [Accepted: 04/12/2014] [Indexed: 06/03/2023]
Abstract
We studied the physiological acclimation of growth, photosynthesis and CO2-concentrating mechanism (CCM) in Cylindrospermopsis raciborskii exposed to low (present day; L-CO2) and high (1300ppm; H-CO2) pCO2. Results showed that under H-CO2 the cell specific division rate (μc) was higher and the CO2- and light-saturated photosynthetic rates (Vmax and Pmax) doubled. The cells' photosynthetic affinity for CO2 (K0.5CO2) was halved compared to L-CO2 cultures. However, no significant differences were found in dark respiration rates (Rd), pigment composition and light harvesting efficiency (α). In H-CO2 cells, non-photochemical quenching (NPQ), associated with state transitions of the electron transport chain (ETC), was negligible. Simultaneously, a reorganisation of PSII features including antenna connectivity (JconPSIIα), heterogeneity (PSIIα/β) and effective absorption cross sectional area (σPSIIα/β) was observed. In relation to different activities of the CCM, our findings suggest that for cells grown under H-CO2: (1) there is down-regulation of CCM activity; (2) the ability of cells to use the harvested light energy is altered; (3) the occurrence of state transitions is likely to be associated with changes of electron flow (cyclic vs linear) through the ETC; (4) changes in PSII characteristics are important in regulating state transitions.
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Affiliation(s)
- Mattia Pierangelini
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia.
| | - Slobodanka Stojkovic
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia; CSIRO Marine and Atmospheric Research, Hobart, Tasmania, Australia
| | - Philip T Orr
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia; Seqwater, PO Box 16146, City East 4002, Queensland, Australia
| | - John Beardall
- School of Biological Science, Monash University, Clayton 3800, Victoria, Australia
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