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Imada T, Yamamoto C, Toyoshima M, Toya Y, Shimizu H. Effect of light fluctuations on photosynthesis and metabolic flux in Synechocystis sp. PCC 6803. Biotechnol Prog 2023; 39:e3326. [PMID: 36700527 DOI: 10.1002/btpr.3326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/07/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023]
Abstract
In nature, photosynthetic organisms are exposed to fluctuating light, and their physiological systems must adapt to this fluctuation. To maintain homeostasis, these organisms have a light fluctuation photoprotective mechanism, which functions in both photosystems and metabolism. Although the photoprotective mechanisms functioning in the photosystem have been studied, it is unclear how metabolism responds to light fluctuations within a few seconds. In the present study, we investigated the metabolic response of Synechocystis sp. PCC 6803 to light fluctuations using 13 C-metabolic flux analysis. The light intensity and duty ratio were adjusted such that the total number of photons or the light intensity during the low-light phase was equal. Light fluctuations affected cell growth and photosynthetic activity under the experimental conditions. However, metabolic flux distributions and cofactor production rates were not affected by the light fluctuations. Furthermore, the estimated ATP and NADPH production rates in the photosystems suggest that NADPH-consuming electron dissipation occurs under fluctuating light conditions. Although we focused on the water-water cycle as the electron dissipation path, no growth effect was observed in an flv3-disrupted strain under fluctuating light, suggesting that another path contributes to electron dissipation under these conditions.
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Affiliation(s)
- Tatsumi Imada
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
| | - Chiaki Yamamoto
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
| | - Masakazu Toyoshima
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
| | - Yoshihiro Toya
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
| | - Hiroshi Shimizu
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
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Zhang X, Sun J, Zhao M. Enhanced metronidazole removal by binary-species photoelectrogenic biofilm of microaglae and anoxygenic phototrophic bacteria. J Environ Sci (China) 2022; 115:25-36. [PMID: 34969452 DOI: 10.1016/j.jes.2021.07.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 06/14/2023]
Abstract
High efficient removal of antibiotics during nutriments recovery for biomass production poses a major technical challenge for photosynthetic microbial biofilm-based wastewater treatment since antibiotics are always co-exist with nutriments in wastewater and resist biodegradation due to their strong biotoxicity and recalcitrance. In this study, we make a first attempt to enhance metronidazole (MNZ) removal from wastewater using electrochemistry-activated binary-species photosynthetic biofilm of Rhodopseudomonas Palustris (R. Palustris) and Chlorella vulgaris (C. vulgaris) by cultivating them under different applied potentials. The results showed that application of external potentials of -0.3, 0 and 0.2 V led to 11, 33 and 26-fold acceleration in MNZ removal, respectively, as compared to that of potential free. The extent of enhancement in MNZ removal was positively correlated to the intensities of photosynthetic current produced under different externally applied potentials. The binary-species photoelectrogenic biofilm exhibited 18 and 6-fold higher MNZ removal rate than that of single-species of C. vulgaris and R. Palustris, respectively, due to the enhanced metabolic interaction between them. Application of an external potential of 0V significantly promoted the accumulation of tryptophan and tyrosine-like compounds as well as humic acid in extracellular polymeric substance, whose concentrations were 7.4, 7.1 and 2.0-fold higher than those produced at potential free, contributing to accelerated adsorption and reductive and photosensitive degradation of MNZ.
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Affiliation(s)
- Xubin Zhang
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Jian Sun
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
| | - Mengmeng Zhao
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
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Cun Z, Wu HM, Zhang JY, Shuang SP, Hong J, Chen JW. Responses of Linear and Cyclic Electron Flow to Nitrogen Stress in an N-Sensitive Species Panax notoginseng. FRONTIERS IN PLANT SCIENCE 2022; 13:796931. [PMID: 35242152 PMCID: PMC8885595 DOI: 10.3389/fpls.2022.796931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Nitrogen (N) is a primary factor limiting leaf photosynthesis. However, the mechanism of N-stress-driven photoinhibition of the photosystem I (PSI) and photosystem II (PSII) is still unclear in the N-sensitive species such as Panax notoginseng, and thus the role of electron transport in PSII and PSI photoinhibition needs to be further understood. We comparatively analyzed photosystem activity, photosynthetic rate, excitation energy distribution, electron transport, OJIP kinetic curve, P700 dark reduction, and antioxidant enzyme activities in low N (LN), moderate N (MN), and high N (HN) leaves treated with linear electron flow (LEF) inhibitor [3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU)] and cyclic electron flow (CEF) inhibitor (methyl viologen, MV). The results showed that the increased application of N fertilizer significantly enhance leaf N contents and specific leaf N (SLN). Net photosynthetic rate (P n) was lower in HN and LN plants than in MN ones. Maximum photochemistry efficiency of PSII (F v/F m), maximum photo-oxidation P700+ (P m), electron transport rate of PSI (ETRI), electron transport rate of PSII (ETRII), and plastoquinone (PQ) pool size were lower in the LN plants. More importantly, K phase and CEF were higher in the LN plants. Additionally, there was not a significant difference in the activity of antioxidant enzyme between the MV- and H2O-treated plants. The results obtained suggest that the lower LEF leads to the hindrance of the formation of ΔpH and ATP in LN plants, thereby damaging the donor side of the PSII oxygen-evolving complex (OEC). The over-reduction of PSI acceptor side is the main cause of PSI photoinhibition under LN condition. Higher CEF and antioxidant enzyme activity not only protected PSI from photodamage but also slowed down the damage rate of PSII in P. notoginseng grown under LN.
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Affiliation(s)
- Zhu Cun
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, China
- National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Yunnan Agricultural University, Kunming, China
| | - Hong-Min Wu
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, China
- National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Yunnan Agricultural University, Kunming, China
| | - Jin-Yan Zhang
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, China
- National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Yunnan Agricultural University, Kunming, China
| | - Sheng-Pu Shuang
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, China
- National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Yunnan Agricultural University, Kunming, China
| | - Jie Hong
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, China
- National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Yunnan Agricultural University, Kunming, China
| | - Jun-Wen Chen
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, China
- National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Yunnan Agricultural University, Kunming, China
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