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Wang K, Mahbub M, Mastroianni G, Valladares A, Mullineaux CW. mRNA localization and thylakoid protein biogenesis in the filamentous heterocyst-forming cyanobacterium Anabaena sp. PCC 7120. J Bacteriol 2024; 206:e0032824. [PMID: 39329528 PMCID: PMC11500504 DOI: 10.1128/jb.00328-24] [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: 08/10/2024] [Accepted: 08/23/2024] [Indexed: 09/28/2024] Open
Abstract
Heterocyst-forming cyanobacteria such as Anabaena (Nostoc) sp. PCC 7120 exhibit extensive remodeling of their thylakoid membranes during heterocyst differentiation. Here we investigate the sites of translation of thylakoid membrane proteins in Anabaena vegetative cells and developing heterocysts, using mRNA fluorescent in situ hybridization (FISH) to detect the location of specific mRNA species. We probed mRNAs encoding reaction center core components and the heterocyst-specific terminal oxidases Cox2 and Cox3. As in unicellular cyanobacteria, the mRNAs encoding membrane-integral thylakoid proteins are concentrated in patches at the inner face of the thylakoid membrane system, adjacent to the central cytoplasm. These patches mark the putative sites of translation and membrane insertion of these proteins. Oxidase activity in mature heterocysts is concentrated in the specialized "honeycomb" regions of the thylakoid membranes close to the cell poles. However, cox2 and cox3 mRNAs remain evenly distributed over the inner face of the thylakoids, implying that oxidase proteins migrate extensively after translation to reach their destination in the honeycomb membranes. The RNA-binding protein RbpG is the closest Anabaena homolog of Rbp3 in the unicellular cyanobacterium Synechocystis sp. PCC 6803, which we previously showed to be crucial for the correct location of photosynthetic mRNAs. An rbpG null mutant shows decreased cellular levels of photosynthetic mRNAs and photosynthetic complexes, coupled with perturbations to thylakoid membrane organization and lower efficiency of the Photosystem II repair cycle. This suggests that the chaperoning of photosynthetic mRNAs by RbpG is important for the correct coordination of thylakoid protein translation and assembly.IMPORTANCECyanobacteria have a complex thylakoid membrane system which is the site of the photosynthetic light reactions as well as most of the respiratory activity in the cell. Protein targeting to the thylakoids and the spatial organization of thylakoid protein biogenesis remain poorly understood. Further complexity is found in some filamentous cyanobacteria that produce heterocysts, specialized nitrogen-fixing cells in which the thylakoid membranes undergo extensive remodeling. Here we probe mRNA locations to reveal thylakoid translation sites in a heterocyst-forming cyanobacterium. We identify an RNA-binding protein important for the correct co-ordination of thylakoid protein translation and assembly, and we demonstrate the effectiveness of mRNA fluorescent in situ hybridization (FISH) as a way to probe cell-specific gene expression in multicellular cyanobacteria.
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Affiliation(s)
- Kexin Wang
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Moontaha Mahbub
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Giulia Mastroianni
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Ana Valladares
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Conrad W. Mullineaux
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
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Nawaz T, Gu L, Fahad S, Saud S, Bleakley B, Zhou R. Exploring Sustainable Agriculture with Nitrogen-Fixing Cyanobacteria and Nanotechnology. Molecules 2024; 29:2534. [PMID: 38893411 PMCID: PMC11173783 DOI: 10.3390/molecules29112534] [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: 03/21/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 06/21/2024] Open
Abstract
The symbiotic relationship between nitrogen-fixing cyanobacteria and plants offers a promising avenue for sustainable agricultural practices and environmental remediation. This review paper explores the molecular interactions between nitrogen-fixing cyanobacteria and nanoparticles, shedding light on their potential synergies in agricultural nanotechnology. Delving into the evolutionary history and specialized adaptations of cyanobacteria, this paper highlights their pivotal role in fixing atmospheric nitrogen, which is crucial for ecosystem productivity. The review discusses the unique characteristics of metal nanoparticles and their emerging applications in agriculture, including improved nutrient delivery, stress tolerance, and disease resistance. It delves into the complex mechanisms of nanoparticle entry into plant cells, intracellular transport, and localization, uncovering the impact on root-shoot translocation and systemic distribution. Furthermore, the paper elucidates cellular responses to nanoparticle exposure, emphasizing oxidative stress, signaling pathways, and enhanced nutrient uptake. The potential of metal nanoparticles as carriers of essential nutrients and their implications for nutrient-use efficiency and crop yield are also explored. Insights into the modulation of plant stress responses, disease resistance, and phytoremediation strategies demonstrate the multifaceted benefits of nanoparticles in agriculture. Current trends, prospects, and challenges in agricultural nanotechnology are discussed, underscoring the need for responsible and safe nanoparticle utilization. By harnessing the power of nitrogen-fixing cyanobacteria and leveraging the unique attributes of nanoparticles, this review paves the way for innovative, sustainable, and efficient agricultural practices.
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Affiliation(s)
- Taufiq Nawaz
- Department of Biology/Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Liping Gu
- Department of Biology/Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Shah Fahad
- Department of Biology/Microbiology, South Dakota State University, Brookings, SD 57007, USA
- Department of Agronomy, Abdul Wali Khan University Mardan, Mardan 23200, KP, Pakistan
| | - Shah Saud
- College of Life Science, Linyi University, Linyi 276000, China
| | - Bruce Bleakley
- Department of Biology/Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Ruanbao Zhou
- Department of Biology/Microbiology, South Dakota State University, Brookings, SD 57007, USA
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Cassier-Chauvat C, Marceau F, Farci S, Ouchane S, Chauvat F. The Glutathione System: A Journey from Cyanobacteria to Higher Eukaryotes. Antioxidants (Basel) 2023; 12:1199. [PMID: 37371929 DOI: 10.3390/antiox12061199] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
From bacteria to plants and humans, the glutathione system plays a pleiotropic role in cell defense against metabolic, oxidative and metal stresses. Glutathione (GSH), the γ-L-glutamyl-L-cysteinyl-glycine nucleophile tri-peptide, is the central player of this system that acts in redox homeostasis, detoxification and iron metabolism in most living organisms. GSH directly scavenges diverse reactive oxygen species (ROS), such as singlet oxygen, superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide and carbon radicals. It also serves as a cofactor for various enzymes, such as glutaredoxins (Grxs), glutathione peroxidases (Gpxs), glutathione reductase (GR) and glutathione-S-transferases (GSTs), which play crucial roles in cell detoxication. This review summarizes what is known concerning the GSH-system (GSH, GSH-derived metabolites and GSH-dependent enzymes) in selected model organisms (Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana and human), emphasizing cyanobacteria for the following reasons. Cyanobacteria are environmentally crucial and biotechnologically important organisms that are regarded as having evolved photosynthesis and the GSH system to protect themselves against the ROS produced by their active photoautotrophic metabolism. Furthermore, cyanobacteria synthesize the GSH-derived metabolites, ergothioneine and phytochelatin, that play crucial roles in cell detoxication in humans and plants, respectively. Cyanobacteria also synthesize the thiol-less GSH homologs ophthalmate and norophthalmate that serve as biomarkers of various diseases in humans. Hence, cyanobacteria are well-suited to thoroughly analyze the role/specificity/redundancy of the players of the GSH-system using a genetic approach (deletion/overproduction) that is hardly feasible with other model organisms (E. coli and S. cerevisiae do not synthesize ergothioneine, while plants and humans acquire it from their soil and their diet, respectively).
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Affiliation(s)
- Corinne Cassier-Chauvat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Fanny Marceau
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Sandrine Farci
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Soufian Ouchane
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Franck Chauvat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
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Quaye JA, Gadda G. The Pseudomonas aeruginosa PAO1 metallo flavoprotein d-2-hydroxyglutarate dehydrogenase requires Zn 2+ for substrate orientation and activation. J Biol Chem 2023; 299:103008. [PMID: 36775127 PMCID: PMC10034468 DOI: 10.1016/j.jbc.2023.103008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Pseudomonas aeruginosa PAO1 d-2-hydroxyglutarate (D2HG) dehydrogenase (PaD2HGDH) oxidizes D2HG to 2-ketoglutarate during the vital l-serine biosynthesis and is a potential therapeutic target against P. aeruginosa. PaD2HGDH, which oxidizes d-malate as an alternative substrate, has been demonstrated to be a metallo flavoprotein that requires Zn2+ for activity. However, the role of Zn2+ in the enzyme has not been elucidated, making it difficult to rationalize why nature employs both a redox center and a metal ion for catalysis in PaD2HGDH and other metallo flavoenzymes. In this study, recombinant His-tagged PaD2HGDH was purified to high levels in the presence of Zn2+ or Co2+ to investigate the metal's role in catalysis. We found that the flavin reduction step was reversible and partially rate limiting for the enzyme's turnover at pH 7.4 with either D2HG or d-malate with similar rate constants for both substrates, irrespective of whether Zn2+ or Co2+ was bound to the enzyme. The steady-state pL profiles of the kcat and kcat/Km values with d-malate demonstrate that Zn2+ mediates the activation of water coordinated to the metal. Our data are consistent with a dual role for the metal, which orients the hydroxy acid substrate in the enzyme's active site and rapidly deprotonates the substrate to yield an alkoxide species for hydride transfer to the flavin. Thus, we propose a catalytic mechanism for PaD2HGDH oxidation that establishes Zn2+ as a cofactor required for substrate orientation and activation during enzymatic turnover.
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Affiliation(s)
- Joanna A Quaye
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Giovanni Gadda
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA; Department of Biology, Georgia State University, Atlanta, Georgia, USA; Department of The Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA.
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5
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Quaye JA, Gadda G. Uncovering Zn 2+ as a cofactor of FAD-dependent Pseudomonas aeruginosa PAO1 d-2-hydroxyglutarate dehydrogenase. J Biol Chem 2023; 299:103007. [PMID: 36775126 PMCID: PMC10025160 DOI: 10.1016/j.jbc.2023.103007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Pseudomonas aeruginosa couples the oxidation of d-2-hydroxyglutarate (D2HG) to l-serine biosynthesis for survival, using d-2-hydroxyglutarate dehydrogenase from P. aeruginosa (PaD2HGDH). Knockout of PaD2HGDH impedes P. aeruginosa growth, making PaD2HGDH a potential target for therapeutics. Previous studies showed that the enzyme's activity increased with Zn2+, Co2+, or Mn2+ but did not establish the enzyme's metal composition and whether the metal is an activator or a required cofactor for the enzyme, which we addressed in this study. Comparable to the human enzyme, PaD2HGDH showed only 15% flavin reduction with D2HG or d-malate. Upon purifying PaD2HGDH with 1 mM Zn2+, the Zn2+:protein stoichiometry was 2:1, yielding an enzyme with ∼40 s-1kcat for d-malate. Treatment with 1 mM EDTA decreased the Zn2+:protein ratio to 1:1 without changing the kinetic parameters with d-malate. We observed complete enzyme inactivation for the metalloapoenzyme with 100 mM EDTA treatment, suggesting that Zn2+ is essential for PaD2HGDH activity. The presence of Zn2+ increased the flavin N3 atom pKa value to 11.9, decreased the flavin ε450 at pH 7.4 from 13.5 to 11.8 mM-1 cm-1, and yielded a charged transfer complex with a broad absorbance band >550 nm, consistent with a Zn2+-hydrate species altering the electronic properties of the enzyme-bound FAD. The exogenous addition of Zn2+, Co2+, Cd2+, Mn2+, or Ni2+ to the metalloapoenzyme reactivated the enzyme in a sigmoidal pattern, consistent with an induced fit rapid-rearrangement mechanism. Collectively, our data demonstrate that PaD2HGDH is a Zn2+-dependent metallo flavoprotein, which requires Zn2+ as an essential cofactor for enzyme activity.
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Affiliation(s)
- Joanna A Quaye
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Giovanni Gadda
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA; Department of Biology, Georgia State University, Atlanta, Georgia, USA; The Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA.
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Gurusamy S, Sankarganesh M, Nandini Asha R, Mathavan A. Biologically active oxovanadium(IV) Schiff base metal complex: antibacterial, antioxidant, biomolecular interaction and molecular docking studies. J Biomol Struct Dyn 2023; 41:599-610. [PMID: 34889705 DOI: 10.1080/07391102.2021.2009916] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The oxovanadium(IV) Schiff base metal complex (ISNPV) have been synthesized as well as characterized by using micro analytical and traditional spectroscopic techniques. The spectral findings were utilized to validate the formation of ISNPV with structure exhibited square pyramidal geometry. The in vitro antibacterial activities of ISNPV were investigated to five different bacterial stains such as S. aureus, S. epidermidis, B. cereus, B. amyloliquefaciens and B. subtilis. The obtained result have suggested that the ISNPV has highest antibacterial activity against S. aureus than the other bacterial stains. The in vitro antioxidant activity like DPPH free radical scavenging assay method was studied by ISNPV in DMSO medium. Because it scavenges all free radicals, the ISNPV possesses higher antioxidant activity than the free ligand. UV-visible absorption and emission spectral techniques were used to investigate the binding of CT-DNA to the ISNPV. Both the spectral data indicate that the ISNPV binds the double helix structure of CT-DNA via an intercalation mode. Additionally, investigate the interactions of ISNPV with the protein molecules like BSA/HAS has been investigated using absorption and emission techniques. The absorption intensity of metal complex increases as well as the emission intensity of protein molecules ability decreases due to the binding nature of ISNPV with BSA/HSA protein molecules. The binding nature of ISNPV with bio molecules such as CT-DNA, BSA and HSA was also validated using molecular docking approach.
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Affiliation(s)
- Shunmugasundaram Gurusamy
- Department of Chemistry, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India.,Affiliated to Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India
| | - Murugesan Sankarganesh
- Department of Chemistry, Saveetha School of Engineeing, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamilnadu, India
| | | | - Alagarsamy Mathavan
- Department of Chemistry, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India
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Hosseinzadeh B, Ahmadi M. Coordination geometry in metallo-supramolecular polymer networks. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214733] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hlihor RM, Roșca M, Hagiu-Zaleschi L, Simion IM, Daraban GM, Stoleru V. Medicinal Plant Growth in Heavy Metals Contaminated Soils: Responses to Metal Stress and Induced Risks to Human Health. TOXICS 2022; 10:toxics10090499. [PMID: 36136464 PMCID: PMC9504071 DOI: 10.3390/toxics10090499] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 05/31/2023]
Abstract
Accelerating heavy metal pollution is a hot issue due to a continuous growth in consumerism and increased activities in various global industries. Soil contamination with heavy metals has resulted in their incorporation into the human food web via plant components. Accumulation and amplification of heavy metals in human tissues through the consumption of medicinal plants can have hazardous health outcomes. Therefore, in this critical review we aim to bring together published information on this subject, with a special highlight on the knowledge gaps related to heavy metal stress in medicinal plants, their responses, and human health related risks. In this respect, this review outlines the key contamination sources of heavy metals in plants, as well as the absorption, mobilization and translocation of metal ions in plant compartments, while considering their respective mechanisms of detoxification. In addition, this literature review attempts to highlight how stress and defensive strategies operate in plants, pointing out the main stressors, either biotic or abiotic (e.g., heavy metals), and the role of reactive oxygen species (ROS) in stress answers. Finally, in our research, we further aim to capture the risks caused by heavy metals in medicinal plants to human health through the assessment of both a hazard quotient (HQ) and hazard index (HI).
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Affiliation(s)
- Raluca Maria Hlihor
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
| | - Mihaela Roșca
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
| | - Laura Hagiu-Zaleschi
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
| | - Isabela Maria Simion
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
| | - Gabriel Mihăiță Daraban
- Department of Organic, Biochemical and Food Engineering, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania
| | - Vasile Stoleru
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
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Yao L, Huang Y, Chen L, He Y. Potential influence of overwintering benthic algae on water quality. J Environ Sci (China) 2022; 117:58-70. [PMID: 35725089 DOI: 10.1016/j.jes.2022.01.021] [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: 10/13/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 06/15/2023]
Abstract
Overwintering benthic algae not only directly impact drinking water safety, but also affect the algae recruitment in warm spring seasons. Thus, understanding the characteristics of overwintering benthic algae can provide scientific references for formulating preventative strategies of reasonable water resource. However, they have received less attention. In this study, the spatiotemporal variation of benthic algae and their harmful secondary metabolites were studied from autumn to summer in Qingcaosha Reservoir. Benthic algae (picophytobenthos accounting for 55.42%) had a high biomass during overwintering, and the groups of overwintering benthic algae included pico-Cyanobacteria, pico-Cryptomonas, pico-Chlorophyta, pico-Diatoms, Cyanobacteria, Chlorophyta, Cryptomonas and Diatoms, which were consistent with the planktonic algae species in warm seasons. In oligotrophic or mesotrophic water bodies, micronutrients of iron and manganese were key nutrient factors influencing the biomass of benthic algae. Furthermore, picophytobenthos were important potential contributors of harmful secondary metabolites. The content of microcystins, anatoxin-a, geosmin and 2-methylisoborneol in sediment were 15.75 µg/kg·FW, 48.16 µg/kg·FW, 3.91 ng/kg·FW, and 11.76 ng/kg·FW during winter, which had potential to be released into water bodies to impact water quality. These findings indicate that water quality monitoring programs need to consider sediment in winter as a potential source of toxins and preventative measures to prevent excessive proliferation of algae should be implemented in winter.
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Affiliation(s)
- Lefan Yao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuansheng Huang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lei Chen
- National Engineering Research Center of Urban Water Resources, Shanghai 200082, China
| | - Yiliang He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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Functional Diversity of TonB-Like Proteins in the Heterocyst-Forming Cyanobacterium Anabaena sp. PCC 7120. mSphere 2021; 6:e0021421. [PMID: 34787445 PMCID: PMC8597729 DOI: 10.1128/msphere.00214-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The TonB-dependent transport of scarcely available substrates across the outer membrane is a conserved feature in Gram-negative bacteria. The plasma membrane-embedded TonB-ExbB-ExbD accomplishes complex functions as an energy transducer by physically interacting with TonB-dependent outer membrane transporters (TBDTs). TonB mediates structural rearrangements in the substrate-loaded TBDTs that are required for substrate translocation into the periplasm. In the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120, four TonB-like proteins have been identified. Out of these TonB3 accomplishes the transport of ferric schizokinen, the siderophore which is secreted by Anabaena to scavenge iron. In contrast, TonB1 (SjdR) is exceptionally short and not involved in schizokinen transport. The proposed function of SjdR in peptidoglycan structuring eliminates the protein from the list of TonB proteins in Anabaena. Compared with the well-characterized properties of SjdR and TonB3, the functions of TonB2 and TonB4 are yet unknown. Here, we examined tonB2 and tonB4 mutants for siderophore transport capacities and other specific phenotypic features. Both mutants were not or only slightly affected in schizokinen transport, whereas they showed decreased nitrogenase activity in apparently normal heterocysts. Moreover, the cellular metal concentrations and pigment contents were altered in the mutants, most pronouncedly in the tonB2 mutant. This strain showed an altered susceptibility toward antibiotics and SDS and formed cell aggregates when grown in liquid culture, a phenotype associated with an elevated lipopolysaccharide (LPS) production. Thus, the TonB-like proteins in Anabaena appear to take over distinct functions, and the mutation of TonB2 strongly influences outer membrane integrity. IMPORTANCE The genomes of many organisms encode more than one TonB protein, and their number does not necessarily correlate with that of TonB-dependent outer membrane transporters. Consequently, specific as well as redundant functions of the different TonB proteins have been identified. In addition to a role in uptake of scarcely available nutrients, including iron complexes, TonB proteins are related to virulence, flagellum assembly, pilus localization, or envelope integrity, including antibiotic resistance. The knowledge about the function of TonB proteins in cyanobacteria is limited. Here, we compare the four TonB proteins of Anabaena sp. strain PCC 7120, providing evidence that their functions are in part distinct, since mutants of these proteins exhibit specific features but also show some common impairments.
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Schätzle H, Arévalo S, Flores E, Schleiff E. A TonB-Like Protein, SjdR, Is Involved in the Structural Definition of the Intercellular Septa in the Heterocyst-Forming Cyanobacterium Anabaena. mBio 2021; 12:e0048321. [PMID: 34101487 PMCID: PMC8262864 DOI: 10.1128/mbio.00483-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022] Open
Abstract
Cyanobacteria are photosynthetic organisms with a Gram-negative envelope structure. Certain filamentous species such as Anabaena sp. strain PCC 7120 can fix dinitrogen upon depletion of combined nitrogen. Because the nitrogen-fixing enzyme, nitrogenase, is oxygen sensitive, photosynthesis and nitrogen fixation are spatially separated in Anabaena. Nitrogen fixation takes place in specialized cells called heterocysts, which differentiate from vegetative cells. During heterocyst differentiation, a microoxic environment is created by dismantling photosystem II and restructuring the cell wall. Moreover, solute exchange between the different cell types is regulated to limit oxygen influx into the heterocyst. The septal zone containing nanopores for solute exchange is constricted between heterocysts and vegetative cells, and cyanophycin plugs are located at the heterocyst poles. We identified a protein previously annotated as TonB1 that is largely conserved among cyanobacteria. A mutant of the encoding gene formed heterocysts but was impaired in diazotrophic growth. Mutant heterocysts appeared elongated and exhibited abnormal morphological features, including a reduced cyanophycin plug, an enhanced septum size, and a restricted nanopore zone in the septum. In spite of this, the intercellular transfer velocity of the fluorescent marker calcein was increased in the mutant compared to the wild type. Thus, the protein is required for proper formation of septal structures, expanding our emerging understanding of Anabaena peptidoglycan plasticity and intercellular solute exchange, and is therefore renamed SjdR (septal junction disk regulator). Notably, calcium supplementation compensated for the impaired diazotrophic growth and alterations in septal peptidoglycan in the sjdR mutant, emphasizing the importance of calcium for cell wall structure. IMPORTANCE Multicellularity in bacteria confers an improved adaptive capacity to environmental conditions and stresses. This includes an enhanced capability of resource utilization through a distribution of biochemical processes between constituent cells. This specialization results in a mutual dependency of different cell types, as is the case for nitrogen-fixing heterocysts and photosynthetically active vegetative cells in Anabaena. In this cyanobacterium, intercellular solute exchange is facilitated through nanopores in the peptidoglycan between adjacent cells. To ensure functionality of the specialized cells, septal size as well as the position, size, and frequency of nanopores in the septum need to be tightly established. The novel septal junction disk regulator SjdR characterized here is conserved in the cyanobacterial phylum. It influences septal size and septal nanopore distribution. Consequently, its absence severely affects the intercellular communication and the strains' growth capacity under nitrogen depletion. Thus, SjdR is involved in septal structure remodeling in cyanobacteria.
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Affiliation(s)
- Hannah Schätzle
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- FIERCE, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Sergio Arévalo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- FIERCE, Goethe University Frankfurt, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
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Koksharova OA, Butenko IO, Pobeguts OV, Safronova NA, Govorun VM. β-N-Methylamino-L-Alanine (BMAA) Causes Severe Stress in Nostoc sp. PCC 7120 Cells under Diazotrophic Conditions: A Proteomic Study. Toxins (Basel) 2021; 13:325. [PMID: 33946501 PMCID: PMC8147232 DOI: 10.3390/toxins13050325] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 04/07/2021] [Accepted: 04/28/2021] [Indexed: 12/24/2022] Open
Abstract
Non-proteinogenic neurotoxic amino acid β-N-methylamino-L-alanine (BMAA) is synthesized by cyanobacteria, diatoms, and dinoflagellates, and is known to be a causative agent of human neurodegenerative diseases. Different phytoplankton organisms' ability to synthesize BMAA could indicate the importance of this molecule in the interactions between microalgae in nature. We were interested in the following: what kinds of mechanisms underline BMAA's action on cyanobacterial cells in different nitrogen supply conditions. Herein, we present a proteomic analysis of filamentous cyanobacteria Nostoc sp. PCC 7120 cells that underwent BMAA treatment in diazotrophic conditions. In diazotrophic growth conditions, to survive, cyanobacteria can use only biological nitrogen fixation to obtain nitrogen for life. Note that nitrogen fixation is an energy-consuming process. In total, 1567 different proteins of Nostoc sp. PCC 7120 were identified by using LC-MS/MS spectrometry. Among them, 123 proteins belonging to different functional categories were selected-due to their notable expression differences-for further functional analysis and discussion. The presented proteomic data evidences that BMAA treatment leads to very strong (up to 80%) downregulation of α (NifD) and β (NifK) subunits of molybdenum-iron protein, which is known to be a part of nitrogenase. This enzyme is responsible for catalyzing nitrogen fixation. The genes nifD and nifK are under transcriptional control of a global nitrogen regulator NtcA. In this study, we have found that BMAA impacts in a total of 22 proteins that are under the control of NtcA. Moreover, BMAA downregulates 18 proteins that belong to photosystems I or II and light-harvesting complexes; BMAA treatment under diazotrophic conditions also downregulates five subunits of ATP synthase and enzyme NAD(P)H-quinone oxidoreductase. Therefore, we can conclude that the disbalance in energy and metabolite amounts leads to severe intracellular stress that induces the upregulation of stress-activated proteins, such as starvation-inducible DNA-binding protein, four SOS-response enzymes, and DNA repair enzymes, nine stress-response enzymes, and four proteases. The presented data provide new leads into the ecological impact of BMAA on microalgal communities that can be used in future investigations.
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Affiliation(s)
- Olga A. Koksharova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 1-40, 119991 Moscow, Russia;
- Institute of Molecular Genetics of National Research Center “Kurchatov Institute”, Kurchatov Square, 2, 123182 Moscow, Russia
| | - Ivan O. Butenko
- Scientific-Research Institute of Physical-Chemical Medicine, 119435 Moscow, Russia; (I.O.B.); (O.V.P.); (V.M.G.)
| | - Olga V. Pobeguts
- Scientific-Research Institute of Physical-Chemical Medicine, 119435 Moscow, Russia; (I.O.B.); (O.V.P.); (V.M.G.)
| | - Nina A. Safronova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 1-40, 119991 Moscow, Russia;
| | - Vadim M. Govorun
- Scientific-Research Institute of Physical-Chemical Medicine, 119435 Moscow, Russia; (I.O.B.); (O.V.P.); (V.M.G.)
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13
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Abstract
The biological process of photosynthesis was critical in catalyzing the oxygenation of Earth’s atmosphere 2.5 billion years ago, changing the course of development of life on Earth. Recently, the fields of applied and synthetic photosynthesis have utilized the light-driven protein–pigment supercomplexes central to photosynthesis for the photocatalytic production of fuel and other various valuable products. The reaction center Photosystem I is of particular interest in applied photosynthesis due to its high stability post-purification, non-geopolitical limitation, and its ability to generate the greatest reducing power found in nature. These remarkable properties have been harnessed for the photocatalytic production of a number of valuable products in the applied photosynthesis research field. These primarily include photocurrents and molecular hydrogen as fuels. The use of artificial reaction centers to generate substrates and reducing equivalents to drive non-photoactive enzymes for valuable product generation has been a long-standing area of interest in the synthetic photosynthesis research field. In this review, we cover advances in these areas and further speculate synthetic and applied photosynthesis as photocatalysts for the generation of valuable products.
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14
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Khan N, Chen X, Geiger JD. Role of Divalent Cations in HIV-1 Replication and Pathogenicity. Viruses 2020; 12:E471. [PMID: 32326317 PMCID: PMC7232465 DOI: 10.3390/v12040471] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/09/2020] [Accepted: 04/18/2020] [Indexed: 12/22/2022] Open
Abstract
Divalent cations are essential for life and are fundamentally important coordinators of cellular metabolism, cell growth, host-pathogen interactions, and cell death. Specifically, for human immunodeficiency virus type-1 (HIV-1), divalent cations are required for interactions between viral and host factors that govern HIV-1 replication and pathogenicity. Homeostatic regulation of divalent cations' levels and actions appear to change as HIV-1 infection progresses and as changes occur between HIV-1 and the host. In people living with HIV-1, dietary supplementation with divalent cations may increase HIV-1 replication, whereas cation chelation may suppress HIV-1 replication and decrease disease progression. Here, we review literature on the roles of zinc (Zn2+), iron (Fe2+), manganese (Mn2+), magnesium (Mg2+), selenium (Se2+), and copper (Cu2+) in HIV-1 replication and pathogenicity, as well as evidence that divalent cation levels and actions may be targeted therapeutically in people living with HIV-1.
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Affiliation(s)
| | | | - Jonathan D. Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA; (N.K.); (X.C.)
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15
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Chen M, Perez-Boerema A, Zhang L, Li Y, Yang M, Li S, Amunts A. Distinct structural modulation of photosystem I and lipid environment stabilizes its tetrameric assembly. NATURE PLANTS 2020; 6:314-320. [PMID: 32170279 DOI: 10.1038/s41477-020-0610-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 01/30/2020] [Indexed: 05/19/2023]
Abstract
Photosystem I (PSI) is able to form different oligomeric states across various species. To reveal the structural basis for PSI dimerization and tetramerization, we structurally investigated PSI from the cyanobacterium Anabaena. This revealed a disrupted trimerization domain due to lack of the terminal residues of PsaL in the lumen, which resulted in PSI dimers with loose connections between monomers and weaker energy-coupled chlorophylls than in the trimer. At the dimer surface, specific phospholipids, cofactors and interactions in combination facilitated recruitment of another dimer to form a tetramer. Taken together, the relaxed luminal connections and lipid specificity at the dimer interface account for membrane curvature. PSI tetramer assembly appears to increase the surface area of the thylakoid membrane, which would contribute to PSI crowding.
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Affiliation(s)
- Ming Chen
- Beijing Engineering Research Center for Biofuels, Institute of Nuclear and New, Energy Technology, Tsinghua University, Beijing, P. R. China
| | - Annemarie Perez-Boerema
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint, Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, P. R. China
| | - Yanxue Li
- Beijing Engineering Research Center for Biofuels, Institute of Nuclear and New, Energy Technology, Tsinghua University, Beijing, P. R. China
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint, Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, P. R. China
| | - Shizhong Li
- Beijing Engineering Research Center for Biofuels, Institute of Nuclear and New, Energy Technology, Tsinghua University, Beijing, P. R. China.
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
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16
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Sohtun WP, Muthuramalingam S, Velusamy M, Mayilmurugan R. New class of tridentate 3N ligands and copper(II) complexes: A model for type-2 copper site of phenoxazinone synthase. INORG CHEM COMMUN 2019. [DOI: 10.1016/j.inoche.2019.107608] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Lin YW. Rational Design of Artificial Metalloproteins and Metalloenzymes with Metal Clusters. Molecules 2019; 24:E2743. [PMID: 31362341 PMCID: PMC6696605 DOI: 10.3390/molecules24152743] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 01/22/2023] Open
Abstract
Metalloproteins and metalloenzymes play important roles in biological systems by using the limited metal ions, complexes, and clusters that are associated with the protein matrix. The design of artificial metalloproteins and metalloenzymes not only reveals the structure and function relationship of natural proteins, but also enables the synthesis of artificial proteins and enzymes with improved properties and functions. Acknowledging the progress in rational design from single to multiple active sites, this review focuses on recent achievements in the design of artificial metalloproteins and metalloenzymes with metal clusters, including zinc clusters, cadmium clusters, iron-sulfur clusters, and copper-sulfur clusters, as well as noble metal clusters and others. These metal clusters were designed in both native and de novo protein scaffolds for structural roles, electron transfer, or catalysis. Some synthetic metal clusters as functional models of native enzymes are also discussed. These achievements provide valuable insights for deep understanding of the natural proteins and enzymes, and practical clues for the further design of artificial enzymes with functions comparable or even beyond those of natural counterparts.
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Affiliation(s)
- Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
- Laboratory of Protein Structure and Function, University of South China, Hengyang 421001, China.
- Hunan Key Laboratory for the Design and Application of Actinide Complexes, University of South China, Hengyang 421001, China.
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18
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Fernandes HS, Teixeira CSS, Sousa SF, Cerqueira NMFSA. Formation of Unstable and very Reactive Chemical Species Catalyzed by Metalloenzymes: A Mechanistic Overview. Molecules 2019; 24:E2462. [PMID: 31277490 PMCID: PMC6651669 DOI: 10.3390/molecules24132462] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 11/16/2022] Open
Abstract
Nature has tailored a wide range of metalloenzymes that play a vast array of functions in all living organisms and from which their survival and evolution depends on. These enzymes catalyze some of the most important biological processes in nature, such as photosynthesis, respiration, water oxidation, molecular oxygen reduction, and nitrogen fixation. They are also among the most proficient catalysts in terms of their activity, selectivity, and ability to operate at mild conditions of temperature, pH, and pressure. In the absence of these enzymes, these reactions would proceed very slowly, if at all, suggesting that these enzymes made the way for the emergence of life as we know today. In this review, the structure and catalytic mechanism of a selection of diverse metalloenzymes that are involved in the production of highly reactive and unstable species, such as hydroxide anions, hydrides, radical species, and superoxide molecules are analyzed. The formation of such reaction intermediates is very difficult to occur under biological conditions and only a rationalized selection of a particular metal ion, coordinated to a very specific group of ligands, and immersed in specific proteins allows these reactions to proceed. Interestingly, different metal coordination spheres can be used to produce the same reactive and unstable species, although through a different chemistry. A selection of hand-picked examples of different metalloenzymes illustrating this diversity is provided and the participation of different metal ions in similar reactions (but involving different mechanism) is discussed.
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Affiliation(s)
- Henrique S Fernandes
- UCIBIO@REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Carla S Silva Teixeira
- UCIBIO@REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Sérgio F Sousa
- UCIBIO@REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Nuno M F S A Cerqueira
- UCIBIO@REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal.
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19
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Herrero A, Flores E. Developmental Biology in Cyanobacteria. Life (Basel) 2019; 9:life9020039. [PMID: 31083350 PMCID: PMC6617022 DOI: 10.3390/life9020039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 05/09/2019] [Indexed: 01/04/2023] Open
Affiliation(s)
- Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, 41004 Seville, Spain.
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, 41004 Seville, Spain.
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