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Yin L, Xu L, Shi K, Chen W, Zhang Y, Wang J, An J, He H, Yang S, Ni L, Li S. Physiology, microcystin production, and transcriptomic responses of Microcystis aeruginosa exposed to calcium and magnesium. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169786. [PMID: 38181954 DOI: 10.1016/j.scitotenv.2023.169786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/07/2024]
Abstract
Calcium ions (Ca2+) and magnesium ions (Mg2+) are pivotal in the community composition and stability of harmful cyanobacteria, yet the physiological and molecular responses remains poorly understood. This study aims to explore these responses in the high microcystin producer Microcystis aeruginosa (M. aeruginosa). Results indicate that the growth of M. aeruginosa is inhibited by Ca2+/Mg2+ exposure (0.5-10 mM), while Fv/Fm photosynthetic parameters and extracellular microcystin-leucine-arginine (MC-LR) concentrations increase. Additionally, MC-LR release is significantly elevated under exposure to Ca2+/Mg2+, posing potential aquatic environmental risks. Transcriptomic analysis reveals downregulation of genes related to cell architecture, membrane transport, and metabolism, while the genes linked to photosynthesis electron transmission and heavy metal-responsive transcriptional regulators are upregulated to adapt to environmental changes. Further analysis reveals that Ca2+ and Mg2+ primarily impact sulfur metabolism and transport of amino acids and mineral within cells. These findings provide insights into M. aeruginosa cells responses to Ca2+ and Mg2+ exposure.
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Affiliation(s)
- Li Yin
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Lin Xu
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Kaipian Shi
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Weiyu Chen
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Yong Zhang
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Juan Wang
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Junfeng An
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Shaogui Yang
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Lixiao Ni
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, School of Environment, Hohai University, Nanjing 210098, China
| | - Shiyin Li
- School of Environment, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China.
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A protease-mediated mechanism regulates the cytochrome c 6/plastocyanin switch in Synechocystis sp. PCC 6803. Proc Natl Acad Sci U S A 2021; 118:2017898118. [PMID: 33495331 DOI: 10.1073/pnas.2017898118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
After the Great Oxidation Event (GOE), iron availability was greatly decreased, and photosynthetic organisms evolved several alternative proteins and mechanisms. One of these proteins, plastocyanin, is a type I blue-copper protein that can replace cytochrome c 6 as a soluble electron carrier between cytochrome b 6 f and photosystem I. In most cyanobacteria, expression of these two alternative proteins is regulated by copper availability, but the regulatory system remains unknown. Herein, we provide evidence that the regulatory system is composed of a BlaI/CopY-family transcription factor (PetR) and a BlaR-membrane protease (PetP). PetR represses petE (plastocyanin) expression and activates petJ (cytochrome c 6), while PetP controls PetR levels in vivo. Using whole-cell extracts, we demonstrated that PetR degradation requires both PetP and copper. Transcriptomic analysis revealed that the PetRP system regulates only four genes (petE, petJ, slr0601, and slr0602), highlighting its specificity. Furthermore, the presence of petE and petRP in early branching cyanobacteria indicates that acquisition of these genes could represent an early adaptation to decreased iron bioavailability following the GOE.
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In vivo electron donation from plastocyanin and cytochrome c 6 to PSI in Synechocystis sp. PCC6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148449. [PMID: 34004195 DOI: 10.1016/j.bbabio.2021.148449] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/30/2021] [Accepted: 05/14/2021] [Indexed: 11/20/2022]
Abstract
Many cyanobacteria species can use both plastocyanin and cytochrome c6 as lumenal electron carriers to shuttle electrons from the cytochrome b6f to either photosystem I or the respiratory cytochrome c oxidase. In Synechocystis sp. PCC6803 placed in darkness, about 60% of the active PSI centres are bound to a reduced electron donor which is responsible for the fast re-reduction of P700in vivo after a single charge separation. Here, we show that both cytochrome c6 and plastocyanin can bind to PSI in the dark and participate to the fast phase of P700 reduction, but the fraction of pre-bound PSI is smaller in the case of cytochrome c6 than with plastocyanin. Because of the inter-connection of respiration and photosynthesis in cyanobacteria, the inhibition of the cytochrome c oxidase results in the over-reduction of the photosynthetic electron transfer chain in the dark that translates into a lag in the kinetics of P700 oxidation at the onset of light. We show that this is true both with plastocyanin and cytochrome c6, indicating that the partitioning of electron transport between respiration and photosynthesis is regulated in the same way independently of which of the two lumenal electron carriers is present, although the mechanisms of such regulation are yet to be understood.
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Arisaka S, Sukigara H, Osanai T. Genetic manipulation to overexpress rpaA altered photosynthetic electron transport in Synechocystis sp. PCC 6803. J Biosci Bioeng 2018. [DOI: 10.1016/j.jbiosc.2018.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Qu J, Shen L, Zhao M, Li W, Jia C, Zhu H, Zhang Q. Determination of the Role of Microcystis aeruginosa in Toxin Generation Based on Phosphoproteomic Profiles. Toxins (Basel) 2018; 10:toxins10070304. [PMID: 30041444 PMCID: PMC6070999 DOI: 10.3390/toxins10070304] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/12/2018] [Accepted: 07/17/2018] [Indexed: 01/06/2023] Open
Abstract
Microcystis aeruginosa is the most common species responsible for toxic cyanobacterial blooms and is considered a significant contributor to the production of cyanotoxins, particularly the potent liver toxins called microcystins. Numerous studies investigating Microcystis spp. blooms have revealed their deleterious effects in freshwater environments. However, the available knowledge regarding the global phosphoproteomics of M. aeruginosa and their regulatory roles in toxin generation is limited. In this study, we conducted comparative phosphoproteomic profiling of non-toxic and toxin-producing strains of M. aeruginosa. We identified 59 phosphorylation sites in 37 proteins in a non-toxic strain and 26 phosphorylation sites in 18 proteins in a toxin-producing strain. The analysis of protein phosphorylation abundances and functions in redox homeostasis, energy metabolism, light absorption and photosynthesis showed marked differences between the non-toxic and toxin-producing strains of M. aeruginosa, indicating that these processes are strongly related to toxin generation. Moreover, the protein-protein interaction results indicated that BJ0JVG8 can directly interact with the PemK-like toxin protein B0JQN8. Thus, the phosphorylation of B0JQN8 appears to be associated with the regulatory roles of toxins in physiological activity.
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Affiliation(s)
- Jiangqi Qu
- Beijing Key Laboratory of Fishery Biotechnology, Beijing Fisheries Research Institute, Beijing 100068, China.
| | - Liping Shen
- State key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China.
| | - Meng Zhao
- Beijing Key Laboratory of Fishery Biotechnology, Beijing Fisheries Research Institute, Beijing 100068, China.
| | - Wentong Li
- Beijing Key Laboratory of Fishery Biotechnology, Beijing Fisheries Research Institute, Beijing 100068, China.
| | - Chengxia Jia
- Beijing Key Laboratory of Fishery Biotechnology, Beijing Fisheries Research Institute, Beijing 100068, China.
| | - Hua Zhu
- Beijing Key Laboratory of Fishery Biotechnology, Beijing Fisheries Research Institute, Beijing 100068, China.
| | - Qingjing Zhang
- Beijing Key Laboratory of Fishery Biotechnology, Beijing Fisheries Research Institute, Beijing 100068, China.
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Comparative Targeted Proteomics of the Central Metabolism and Photosystems in SigE Mutant Strains of Synechocystis sp. PCC 6803. Molecules 2018; 23:molecules23051051. [PMID: 29723969 PMCID: PMC6102573 DOI: 10.3390/molecules23051051] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/17/2022] Open
Abstract
A targeted proteome analysis was conducted to investigate the SigE dependent-regulation of central metabolism in Synechocystis sp. PCC 6803 by directly comparing the protein abundance profiles among the wild type, a sigE deletion mutant (ΔsigE), and a sigE over-expression (sigEox) strains. Expression levels of 112 target proteins, including the central metabolism related-enzymes and the subunits of the photosystems, were determined by quantifying the tryptic peptides in the multiple reaction monitoring (MRM) mode of liquid-chromatography–triple quadrupole mass spectrometry (LC–MS/MS). Comparison with gene-expression data showed that although the abundance of Gnd protein was closely correlated with that of gnd mRNA, there were poor correlations for GdhA/gdhA and glycogen degradation-related genes such as GlgX/glgX and GlgP/glgP pairs. These results suggested that the regulation of protein translation and degradation played a role in regulating protein abundance. The protein abundance profile suggested that SigE overexpression reduced the proteins involved in photosynthesis and increased GdhA abundance, which is involved in the nitrogen assimilation pathway using NADPH. The results obtained in this study successfully demonstrated that targeted proteome analysis enables direct comparison of the abundance of central metabolism- and photosystem-related proteins.
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