1
|
Doello S, Forchhammer K. Microbial ecophysiology: Shedding light on the re-greening of chlorotic cyanobacteria. Curr Biol 2024; 34:R893-R895. [PMID: 39378846 DOI: 10.1016/j.cub.2024.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
Abstract
Cyanobacteria, key contributors to aquatic CO2 fixation, employ sophisticated acclimation strategies for survival under nitrogen-limited conditions. A new study reveals that red light influences the resuscitation of chlorotic cells through mechanisms involving the dark-operative protochlorophyllide reductase, which facilitates chlorophyll biosynthesis and re-greening under low-light conditions.
Collapse
Affiliation(s)
- Sofía Doello
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany.
| |
Collapse
|
2
|
Krausfeldt LE, Shmakova E, Lee HW, Mazzei V, Loftin KA, Smith RP, Karwacki E, Fortman PE, Rosen BH, Urakawa H, Dadlani M, Colwell RR, Lopez JV. Microbial diversity, genomics, and phage-host interactions of cyanobacterial harmful algal blooms. mSystems 2024; 9:e0070923. [PMID: 38856205 PMCID: PMC11265339 DOI: 10.1128/msystems.00709-23] [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: 07/13/2023] [Accepted: 11/13/2023] [Indexed: 06/11/2024] Open
Abstract
The occurrence of cyanobacterial harmful algal blooms (cyanoHABs) is related to their physical and chemical environment. However, less is known about their associated microbial interactions and processes. In this study, cyanoHABs were analyzed as a microbial ecosystem, using 1 year of 16S rRNA sequencing and 70 metagenomes collected during the bloom season from Lake Okeechobee (Florida, USA). Biogeographical patterns observed in microbial community composition and function reflected ecological zones distinct in their physical and chemical parameters that resulted in bloom "hotspots" near major lake inflows. Changes in relative abundances of taxa within multiple phyla followed increasing bloom severity. Functional pathways that correlated with increasing bloom severity encoded organic nitrogen and phosphorus utilization, storage of nutrients, exchange of genetic material, phage defense, and protection against oxidative stress, suggesting that microbial interactions may promote cyanoHAB resilience. Cyanobacterial communities were highly diverse, with picocyanobacteria ubiquitous and oftentimes most abundant, especially in the absence of blooms. The identification of novel bloom-forming cyanobacteria and genomic comparisons indicated a functionally diverse cyanobacterial community with differences in its capability to store nitrogen using cyanophycin and to defend against phage using CRISPR and restriction-modification systems. Considering blooms in the context of a microbial ecosystem and their interactions in nature, physiologies and interactions supporting the proliferation and stability of cyanoHABs are proposed, including a role for phage infection of picocyanobacteria. This study displayed the power of "-omics" to reveal important biological processes that could support the effective management and prediction of cyanoHABs. IMPORTANCE Cyanobacterial harmful algal blooms pose a significant threat to aquatic ecosystems and human health. Although physical and chemical conditions in aquatic systems that facilitate bloom development are well studied, there are fundamental gaps in the biological understanding of the microbial ecosystem that makes a cyanobacterial bloom. High-throughput sequencing was used to determine the drivers of cyanobacteria blooms in nature. Multiple functions and interactions important to consider in cyanobacterial bloom ecology were identified. The microbial biodiversity of blooms revealed microbial functions, genomic characteristics, and interactions between cyanobacterial populations that could be involved in bloom stability and more coherently define cyanobacteria blooms. Our results highlight the importance of considering cyanobacterial blooms as a microbial ecosystem to predict, prevent, and mitigate them.
Collapse
Affiliation(s)
- Lauren E. Krausfeldt
- Department of Biological Sciences, Guy Harvey Oceanographic Center, Nova Southeastern University, Dania Beach, Florida, USA
| | - Elizaveta Shmakova
- Department of Biological Sciences, Guy Harvey Oceanographic Center, Nova Southeastern University, Dania Beach, Florida, USA
| | - Hyo Won Lee
- Department of Biological Sciences, Guy Harvey Oceanographic Center, Nova Southeastern University, Dania Beach, Florida, USA
| | - Viviana Mazzei
- U.S. Geological Survey, Caribbean–Florida Water Science Center, Orlando, Florida, USA
| | - Keith A. Loftin
- U.S. Geological Survey, Kansas Water Science Center, Lawrence, Kansas, USA
| | - Robert P. Smith
- Department of Biological Sciences, Guy Harvey Oceanographic Center, Nova Southeastern University, Dania Beach, Florida, USA
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA
| | - Emily Karwacki
- U.S. Geological Survey, Caribbean–Florida Water Science Center, Orlando, Florida, USA
| | - P. Eric Fortman
- Department of Biological Sciences, Guy Harvey Oceanographic Center, Nova Southeastern University, Dania Beach, Florida, USA
| | - Barry H. Rosen
- Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, Florida, USA
| | - Hidetoshi Urakawa
- Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, Florida, USA
| | | | - Rita R. Colwell
- Institute for Advanced Computer Studies, University of Maryland College Park, College Park, Maryland, USA
| | - Jose V. Lopez
- Department of Biological Sciences, Guy Harvey Oceanographic Center, Nova Southeastern University, Dania Beach, Florida, USA
| |
Collapse
|
3
|
Lucius S, Hagemann M. The primary carbon metabolism in cyanobacteria and its regulation. FRONTIERS IN PLANT SCIENCE 2024; 15:1417680. [PMID: 39036361 PMCID: PMC11257934 DOI: 10.3389/fpls.2024.1417680] [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: 04/15/2024] [Accepted: 06/24/2024] [Indexed: 07/23/2024]
Abstract
Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis. Many cyanobacterial strains can live in different trophic modes, ranging from photoautotrophic and heterotrophic to mixotrophic growth. However, the regulatory mechanisms allowing a flexible switch between these lifestyles are poorly understood. As anabolic fixation of CO2 in the Calvin-Benson-Bassham (CBB) cycle and catabolic sugar-degradation pathways share intermediates and enzymatic capacity, a tight regulatory network is required to enable simultaneous opposed metabolic fluxes. The Entner-Doudoroff (ED) pathway was recently predicted as one glycolytic route, which cooperates with other pathways in glycogen breakdown. Despite low carbon flux through the ED pathway, metabolite analyses of mutants deficient in the ED pathway revealed a distinct phenotype pointing at a strong regulatory impact of this route. The small Cp12 protein downregulates the CBB cycle in darkness by inhibiting phosphoribulokinase and glyceraldehyde 3-phosphate dehydrogenase. New results of metabolomic and redox level analyses on strains with Cp12 variants extend the known role of Cp12 regulation towards the acclimation to external glucose supply under diurnal conditions as well as to fluctuations in CO2 levels in the light. Moreover, carbon and nitrogen metabolism are closely linked to maintain an essential C/N homeostasis. The small protein PirC was shown to be an important regulator of phosphoglycerate mutase, which identified this enzyme as central branching point for carbon allocation from CBB cycle towards lower glycolysis. Altered metabolite levels in the mutant ΔpirC during nitrogen starvation experiments confirm this regulatory mechanism. The elucidation of novel mechanisms regulating carbon allocation at crucial metabolic branching points could identify ways for targeted redirection of carbon flow towards desired compounds, and thus help to further establish cyanobacteria as green cell factories for biotechnological applications with concurrent utilization of sunlight and CO2.
Collapse
Affiliation(s)
| | - Martin Hagemann
- Department Plant Physiology, University of Rostock, Rostock, Germany
| |
Collapse
|
4
|
Domínguez-Lobo MT, Roldán M, Gutiérrez-Diánez AM, Florencio FJ, Muro-Pastor MI. Double blocking of carbon metabolism causes a large increase of Calvin-Benson cycle compounds in cyanobacteria. PLANT PHYSIOLOGY 2024; 195:1491-1505. [PMID: 38377468 PMCID: PMC11142378 DOI: 10.1093/plphys/kiae083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 01/08/2024] [Accepted: 01/19/2024] [Indexed: 02/22/2024]
Abstract
Carbon-flow-regulator A (CfrA) adapts carbon flux to nitrogen conditions in nondiazotrophic cyanobacteria. Under nitrogen deficiency, CfrA leads to the storage of excess carbon, which cannot combine with nitrogen, mainly as glycogen. cfrA overexpression from the arsenite-inducible, nitrogen-independent ParsB promoter allows analysis of the metabolic effects of CfrA accumulation. Considering that the main consequence of cfrA overexpression is glycogen accumulation, we examined carbon distribution in response to cfrA expression in Synechocystis sp. PCC 6803 strains impaired in synthesizing this polymer. We carried out a comparative phenotypic analysis to evaluate cfrA overexpression in the wild-type strain and in a mutant of ADP-glucose pyrophosphorylase (ΔglgC), which is unable to synthesize glycogen. The accumulation of CfrA in the wild-type background caused a photosynthetic readjustment although growth was not affected. However, in a ΔglgC strain, growth decreased depending on CfrA accumulation and photosynthesis was severely affected. An elemental analysis of the H, C, and N content of cells revealed that cfrA expression in the wild-type caused an increase in the C/N ratio, due to decreased nitrogen assimilation. Metabolomic study indicated that these cells store sucrose and glycosylglycerol, in addition to the previously described glycogen accumulation. However, cells deficient in glycogen synthesis accumulated large amounts of Calvin-Benson cycle intermediates as cfrA was expressed. These cells also showed increased levels of some amino acids, mainly alanine, serine, valine, isoleucine, and leucine. The findings suggest that by controlling cfrA expression, in different conditions and strains, we could change the distribution of fixed carbon, with potential biotechnological benefits.
Collapse
Affiliation(s)
| | - Miguel Roldán
- Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla 41012, Spain
| | - Alba María Gutiérrez-Diánez
- Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla 41012, Spain
| | - Francisco Javier Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla 41012, Spain
| | - María Isabel Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| |
Collapse
|
5
|
Luo C, Chen C, Xian X, Cai WF, Yu X, Ye C. The secondary outbreak risk and mechanisms of Microcystis aeruginosa after H 2O 2 treatment. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134196. [PMID: 38603907 DOI: 10.1016/j.jhazmat.2024.134196] [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: 01/31/2024] [Revised: 03/18/2024] [Accepted: 03/31/2024] [Indexed: 04/13/2024]
Abstract
The secondary outbreak of cyanobacteria after algicide treatment has been a serious problem to water ecosystems. Hydrogen peroxide (H2O2) is an algaecide widely used in practice, but similar re-bloom problems are inevitably encountered. Our work found that Microcystis aeruginosa (M. aeruginosa) temporarily hibernates after H2O2 treatment, but there is still a risk of secondary outbreaks. Interestingly, the dormant period was as long as 20 and 28 days in 5 mg L-1 and 20 mg L-1 H2O2 treatment groups, respectively, but the photosynthetic activity was both restored much earlier (within 14 days). Subsequently, a quantitative imaging flow cytometry-based method was constructed and confirmed that the re-bloom had undergone two stages including first recovery and then re-division. The expression of ftsZ and fabZ genes showed that M. aeruginosa had active transcription processes related to cell division protein and fatty acid synthesis during the dormancy stat. Furthermore, metabolomics suggested that the recovery of M. aeruginosa was mainly by activating folate and salicylic acid synthesis pathways, which promoted environmental stress resistance, DNA synthesis, and cell membrane repair. This study reported the comprehensive mechanisms of secondary outbreak of M. aeruginosa after H2O2 treatment. The findings suggest that optimizing the dosage and frequency of H2O2, as well as exploring the potential use of salicylic acid and folic acid inhibitors, could be promising directions for future algal control strategies.
Collapse
Affiliation(s)
- Chen Luo
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Chenlan Chen
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Xuanxuan Xian
- Ecological &Environment Monitoring Center of Zhejiang Province, Hangzhou 310012, China
| | - Wei-Feng Cai
- Xiamen Cancer Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361103. China
| | - Xin Yu
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China.
| | - Chengsong Ye
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China.
| |
Collapse
|
6
|
Evans SE, Franks AE, Bergman ME, Sethna NS, Currie MA, Phillips MA. Plastid ancestors lacked a complete Entner-Doudoroff pathway, limiting plants to glycolysis and the pentose phosphate pathway. Nat Commun 2024; 15:1102. [PMID: 38321044 PMCID: PMC10847513 DOI: 10.1038/s41467-024-45384-y] [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: 08/17/2023] [Accepted: 01/20/2024] [Indexed: 02/08/2024] Open
Abstract
The Entner-Doudoroff (ED) pathway provides an alternative to glycolysis. It converts 6-phosphogluconate (6-PG) to glyceraldehyde-3-phosphate and pyruvate in two steps consisting of a dehydratase (EDD) and an aldolase (EDA). Here, we investigate its distribution and significance in higher plants and determine the ED pathway is restricted to prokaryotes due to the absence of EDD genes in eukaryotes. EDDs share a common origin with dihydroxy-acid dehydratases (DHADs) of the branched chain amino acid pathway (BCAA). Each dehydratase features strict substrate specificity. E. coli EDD dehydrates 6-PG to 2-keto-3-deoxy-6-phosphogluconate, while DHAD only dehydrates substrates from the BCAA pathway. Structural modeling identifies two divergent domains which account for their non-overlapping substrate affinities. Coupled enzyme assays confirm only EDD participates in the ED pathway. Plastid ancestors lacked EDD but transferred metabolically promiscuous EDA, which explains the absence of the ED pathway from the Viridiplantae and sporadic persistence of EDA genes across the plant kingdom.
Collapse
Affiliation(s)
- Sonia E Evans
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Anya E Franks
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Matthew E Bergman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Nasha S Sethna
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Mark A Currie
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Michael A Phillips
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada.
| |
Collapse
|
7
|
Ran Z, Du Z, Miao G, Zheng M, Luo L, Pang X, Wei L, Li D, Ma W. Identification of a c-type heme oxygenase and its function during acclimation of cyanobacteria to nitrogen fluctuations. Commun Biol 2023; 6:944. [PMID: 37714932 PMCID: PMC10504260 DOI: 10.1038/s42003-023-05315-x] [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: 10/19/2022] [Accepted: 09/01/2023] [Indexed: 09/17/2023] Open
Abstract
The mechanisms of acclimating to a nitrogen-fluctuating environment are necessary for the survival of aquatic cyanobacteria in their natural habitats, but our understanding is still far from complete. Here, the synthesis of phycobiliprotein is confirmed to be much earlier than that of photosystem components during recovery from nitrogen chlorosis and an unknown protein Ssr1698 is discovered to be involved in this synthetic process. The unknown protein is further identified as a c-type heme oxygenase (cHO) in tetrapyrrole biosynthetic pathway and catalyzes the opening of heme ring to form biliverdin IXα, which is required for phycobilin production and ensuing phycobiliprotein synthesis. In addition, the cHO-dependent phycobiliprotein is found to be vital for the growth of cyanobacterial cells during chlorosis and regreening through its nitrogen-storage and light-harvesting functions, respectively. Collectively, the cHO expressed preferentially during recovery from nitrogen chlorosis is identified in photosynthetic organisms and the dual function of this enzyme-dependent phycobiliprotein is proposed to be an important mechanism for acclimation of aquatic cyanobacteria to a nitrogen-fluctuating environment.
Collapse
Affiliation(s)
- Zhaoxing Ran
- School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China
| | - Zhenyu Du
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China
| | - Gengkai Miao
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China
| | - Mei Zheng
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China
| | - Ligang Luo
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China
| | - Xiaoqin Pang
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China
| | - Lanzhen Wei
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China.
| | - Dezhi Li
- School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China.
- Key Laboratory of Urbanization and Ecological Restoration of Shanghai, 200241, Shanghai, China.
- Institute of Eco-Chongming (IEC), 20 Cuiniao Rd, Chenjia Zhen, Chongming, 202162, Shanghai, China.
- Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, 3663 N. Zhongshan Road, 200062, Shanghai, China.
| | - Weimin Ma
- College of Life Sciences, Shanghai Normal University, 200234, Shanghai, China.
| |
Collapse
|
8
|
Doello S, Forchhammer K. Phosphoglucomutase comes into the spotlight. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:1293-1296. [PMID: 36913621 PMCID: PMC10010599 DOI: 10.1093/jxb/erac513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 06/18/2023]
Abstract
This article comments on: Ortega-Martínez P, Roldán M, Díaz-Troya S, Florencio FJ. 2023. Stress response requires an efficient glycogen and central carbon metabolism connection by phosphoglucomutases in cyanobacteria. Journal of Experimental Botany 74, 1532–1550
Collapse
Affiliation(s)
- Sofía Doello
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Germany
| | | |
Collapse
|
9
|
Burkhardt M, Rapp J, Menzel C, Link H, Forchhammer K. The Global Influence of Sodium on Cyanobacteria in Resuscitation from Nitrogen Starvation. BIOLOGY 2023; 12:biology12020159. [PMID: 36829438 PMCID: PMC9952445 DOI: 10.3390/biology12020159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
Dormancy and resuscitation are key to bacterial survival under fluctuating environmental conditions. In the absence of combined nitrogen sources, the non-diazotrophic model cyanobacterium Synechocystis sp. PCC 6803 enters into a metabolically quiescent state during a process termed chlorosis. This state enables the cells to survive until nitrogen sources reappear, whereupon the cells resuscitate in a process that follows a highly orchestrated program. This coincides with a metabolic switch into a heterotrophic-like mode where glycogen catabolism provides the cells with reductant and carbon skeletons for the anabolic reactions that serve to re-establish a photosynthetically active cell. Here we show that the entire resuscitation process requires the presence of sodium, a ubiquitous cation that has a broad impact on bacterial physiology. The requirement for sodium in resuscitating cells persists even at elevated CO2 levels, a condition that, by contrast, relieves the requirement for sodium ions in vegetative cells. Using a multi-pronged approach, including the first metabolome analysis of Synechocystis cells resuscitating from chlorosis, we reveal the involvement of sodium at multiple levels. Not only does sodium play a role in the bioenergetics of chlorotic cells, as previously shown, but it is also involved in nitrogen compound assimilation, pH regulation, and synthesis of key metabolites.
Collapse
Affiliation(s)
- Markus Burkhardt
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Johanna Rapp
- CMFI, Bacterial Metabolomics, University of Tübingen, Auf der Morgenstelle 24, 72076 Tübingen, Germany
| | - Claudia Menzel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Hannes Link
- CMFI, Bacterial Metabolomics, University of Tübingen, Auf der Morgenstelle 24, 72076 Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
- Correspondence:
| |
Collapse
|
10
|
Bachhar A, Jablonsky J. Entner-Doudoroff pathway in Synechocystis PCC 6803: Proposed regulatory roles and enzyme multifunctionalities. Front Microbiol 2022; 13:967545. [PMID: 36051759 PMCID: PMC9424857 DOI: 10.3389/fmicb.2022.967545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
The Entner-Doudoroff pathway (ED-P) was established in 2016 as the fourth glycolytic pathway in Synechocystis sp. PCC 6803. ED-P consists of two reactions, the first catalyzed by 6-phosphogluconate dehydratase (EDD), the second by keto3-deoxygluconate-6-phosphate aldolase/4-hydroxy-2-oxoglutarate aldolase (EDA). ED-P was previously concluded to be a widespread (∼92%) pathway among cyanobacteria, but current bioinformatic analysis estimated the occurrence of ED-P to be either scarce (∼1%) or uncommon (∼47%), depending if dihydroxy-acid dehydratase (ilvD) also functions as EDD (currently assumed). Thus, the biochemical characterization of ilvD is a task pending to resolve this uncertainty. Next, we have provided new insights into several single and double glycolytic mutants based on kinetic model of central carbon metabolism of Synechocystis. The model predicted that silencing 6-phosphogluconate dehydrogenase (gnd) could be coupled with ∼90% down-regulation of G6P-dehydrogenase, also limiting the metabolic flux via ED-P. Furthermore, our metabolic flux estimation implied that growth impairment linked to silenced EDA under mixotrophic conditions is not caused by diminished carbon flux via ED-P but rather by a missing mechanism related to the role of EDA in metabolism. We proposed two possible, mutually non-exclusive explanations: (i) Δeda leads to disrupted carbon catabolite repression, regulated by 2-keto3-deoxygluconate-6-phosphate (ED-P intermediate), and (ii) EDA catalyzes the interconversion between glyoxylate and 4-hydroxy-2-oxoglutarate + pyruvate in the proximity of TCA cycle, possibly effecting the levels of 2-oxoglutarate under Δeda. We have also proposed a new pathway from EDA toward proline, which could explain the proline accumulation under Δeda. In addition, the presented in silico method provides an alternative to 13C metabolic flux analysis for marginal metabolic pathways around/below the threshold of ultrasensitive LC-MS. Finally, our in silico analysis provided alternative explanations for the role of ED-P in Synechocystis while identifying some severe uncertainties.
Collapse
|
11
|
Rueda E, Álvarez-González A, Vila J, Díez-Montero R, Grifoll M, García J. Inorganic carbon stimulates the metabolic routes related to the polyhdroxybutyrate production in a Synechocystis sp. strain (cyanobacteria) isolated from wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 829:154691. [PMID: 35318053 DOI: 10.1016/j.scitotenv.2022.154691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Cyanobacteria are capable of transforming CO2 into polyhydroxybutyrate (PHB). In this study, different inorganic carbon concentrations (0-2 gC L-1) were evaluated for a Synechocystis sp. strain isolated from wastewater. Quantitative RT-qPCR was also performed to decipher the links between inorganic carbon and PHB and glycogen metabolism. 2 gC L-1 of bicarbonate stimulated cell growth, nutrients consumption and production of PHB. Using this concentration, a 14%dcw of PHB and an average productivity of 2.45 mgPHB L-1 d-1 were obtained. Gene expression analysis revelated that these conditions caused the overexpression of genes related to glycogen and PHB synthesis. Moreover, a positive correlation between the genes codifying for the glycogen phosphorylase, the acetyl-CoA reductase and the poly(3-hydroxyalkanoate) polymerase was found, meaning that PHB synthesis and glycogen catabolism are strongly related. These results provide an exhaustive evaluation of the effect of carbon on the PHB production and cyanobacterial metabolism.
Collapse
Affiliation(s)
- Estel Rueda
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Escola d'Enginyeria de Barcelona Est (EEBE), Universitat Politècnica de Catalunya-BarcelonaTech, Av. Eduard Maristany 16, Building C5.1, E-08019 Barcelona, Spain
| | - Ana Álvarez-González
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Joaquim Vila
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Diagonal 643, Barcelona E-08028, Spain
| | - Rubén Díez-Montero
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Magdalena Grifoll
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Diagonal 643, Barcelona E-08028, Spain
| | - Joan García
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain.
| |
Collapse
|
12
|
Doello S, Neumann N, Forchhammer K. Regulatory phosphorylation event of phosphoglucomutase 1 tunes its activity to regulate glycogen metabolism. FEBS J 2022; 289:6005-6020. [PMID: 35509259 DOI: 10.1111/febs.16471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/25/2022] [Accepted: 05/03/2022] [Indexed: 12/24/2022]
Abstract
Regulation of glycogen metabolism is of vital importance in organisms of all three kingdoms of life. Although the pathways involved in glycogen synthesis and degradation are well known, many regulatory aspects around the metabolism of this polysaccharide remain undeciphered. Here, we used the unicellular cyanobacterium Synechocystis as a model to investigate how glycogen metabolism is regulated in nitrogen-starved dormant cells, which entirely rely on glycogen catabolism to resume growth upon nitrogen repletion. We identified phosphoglucomutase 1 (PGM1) as a key regulatory point in glycogen metabolism, and post-translational modification as an essential mechanism for controlling its activity. We could show that PGM1 is phosphorylated ata residue in the regulatory latch domain (Ser 47) during nitrogen starvation, which inhibits its activity. Inactivation of PGM1 by phosphorylation at Ser 47 prevents premature degradation of the glycogen stores and appears to be essential for survival of Synechocystis in the dormant state. Remarkably, this regulatory mechanism seems to be evolutionary conserved in PGM1 enzymes, from bacteria to humans.
Collapse
Affiliation(s)
- Sofía Doello
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Germany
| | - Niels Neumann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Germany
| |
Collapse
|
13
|
Kettner A, Noll M, Griehl C. Leptolyngbya sp. NIVA-CYA 255, a Promising Candidate for Poly(3-hydroxybutyrate) Production under Mixotrophic Deficiency Conditions. Biomolecules 2022; 12:biom12040504. [PMID: 35454093 PMCID: PMC9030801 DOI: 10.3390/biom12040504] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 12/01/2022] Open
Abstract
Cyanobacteria are a promising source for the sustainable production of biodegradable bioplastics such as poly(3-hydroxybutyrate) (PHB). The auto-phototrophic biomass formation is based on light and CO2, which is an advantage compared to heterotrophic PHB-producing systems. So far, only a handful of cyanobacterial species suitable for the high-yield synthesis of PHB have been reported. In the present study, the PHB formation, biomass, and elemental composition of Leptolyngbya sp. NIVA-CYA 255 were investigated. Therefore, a three-stage cultivation process was applied, consisting of a growth stage; an N-, P-, and NP-depleted phototrophic stage; and a subsequent mixotrophic deficiency stage, initiated by sodium acetate supplementation. The extracted cyanobacterial PHB was confirmed by FTIR- and GC-MS analyses. Furthermore, the fluorescent dyes LipidGreen2 and Nile red were used for fluorescence-based monitoring and the visualization of PHB. LipidGreen2 was well suited for PHB quantification, while the application of Nile red was limited by fluorescence emission crosstalk with phycocyanin. The highest PHB yields were detected in NP- (325 mg g−1) and N-deficiency (213 mg g−1). The glycogen pool was reduced in all cultures during mixotrophy, while lipid composition was not affected. The highest glycogen yield was formed under N-deficiency (217 mg g−1). Due to the high carbon storage capacity and PHB formation, Leptolyngbya sp. NIVA-CYA 255 is a promising candidate for PHB production. Further work will focus on upscaling to a technical scale and monitoring the formation by LipidGreen2-based fluorometry.
Collapse
Affiliation(s)
- Alexander Kettner
- Competence Center Algal Biotechnology, Department of Applied Biosciences and Process Engineering, Anhalt University of Applied Sciences, Bernburger Strasse 55, 06366 Koethen, Germany;
| | - Matthias Noll
- Institute of Bioanalysis, Coburg University of Applied Sciences and Arts, Friedrich-Streib-Str. 2, 96450 Coburg, Germany;
| | - Carola Griehl
- Competence Center Algal Biotechnology, Department of Applied Biosciences and Process Engineering, Anhalt University of Applied Sciences, Bernburger Strasse 55, 06366 Koethen, Germany;
- Correspondence: ; Tel.: +49-(0)-3496-67-2526
| |
Collapse
|
14
|
Wang Y, Chen X, Spengler K, Terberger K, Boehm M, Appel J, Barske T, Timm S, Battchikova N, Hagemann M, Gutekunst K. Pyruvate:ferredoxin oxidoreductase and low abundant ferredoxins support aerobic photomixotrophic growth in cyanobacteria. eLife 2022; 11:71339. [PMID: 35138247 PMCID: PMC8887894 DOI: 10.7554/elife.71339] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 02/06/2022] [Indexed: 11/24/2022] Open
Abstract
The decarboxylation of pyruvate is a central reaction in the carbon metabolism of all organisms. It is catalyzed by the pyruvate:ferredoxin oxidoreductase (PFOR) and the pyruvate dehydrogenase (PDH) complex. Whereas PFOR reduces ferredoxin, the PDH complex utilizes NAD+. Anaerobes rely on PFOR, which was replaced during evolution by the PDH complex found in aerobes. Cyanobacteria possess both enzyme systems. Our data challenge the view that PFOR is exclusively utilized for fermentation. Instead, we show, that the cyanobacterial PFOR is stable in the presence of oxygen in vitro and is required for optimal photomixotrophic growth under aerobic and highly reducing conditions while the PDH complex is inactivated. We found that cells rely on a general shift from utilizing NAD(H)- to ferredoxin-dependent enzymes under these conditions. The utilization of ferredoxins instead of NAD(H) saves a greater share of the Gibbs-free energy, instead of wasting it as heat. This obviously simultaneously decelerates metabolic reactions as they operate closer to their thermodynamic equilibrium. It is common thought that during evolution, ferredoxins were replaced by NAD(P)H due to their higher stability in an oxidizing atmosphere. However, the utilization of NAD(P)H could also have been favored due to a higher competitiveness because of an accelerated metabolism.
Collapse
Affiliation(s)
- Yingying Wang
- Department of Biology, Christian-Albrechts University, Kiel, Germany
| | - Xi Chen
- Department of Biology, Christian-Albrechts University, Kiel, Germany
| | | | | | - Marko Boehm
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| | - Jens Appel
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| | - Thomas Barske
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Stefan Timm
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | | | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Kirstin Gutekunst
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| |
Collapse
|
15
|
Selim KA, Haffner M, Burkhardt M, Mantovani O, Neumann N, Albrecht R, Seifert R, Krüger L, Stülke J, Hartmann MD, Hagemann M, Forchhammer K. Diurnal metabolic control in cyanobacteria requires perception of second messenger signaling molecule c-di-AMP by the carbon control protein SbtB. SCIENCE ADVANCES 2021; 7:eabk0568. [PMID: 34878830 PMCID: PMC8654305 DOI: 10.1126/sciadv.abk0568] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Because of their photosynthesis-dependent lifestyle, cyanobacteria evolved sophisticated regulatory mechanisms to adapt to oscillating day-night metabolic changes. How they coordinate the metabolic switch between autotrophic and glycogen-catabolic metabolism in light and darkness is poorly understood. Recently, c-di-AMP has been implicated in diurnal regulation, but its mode of action remains elusive. To unravel the signaling functions of c-di-AMP in cyanobacteria, we isolated c-di-AMP receptor proteins. Thereby, the carbon-sensor protein SbtB was identified as a major c-di-AMP receptor, which we confirmed biochemically and by x-ray crystallography. In search for the c-di-AMP signaling function of SbtB, we found that both SbtB and c-di-AMP cyclase–deficient mutants showed reduced diurnal growth and that c-di-AMP–bound SbtB interacts specifically with the glycogen-branching enzyme GlgB. Accordingly, both mutants displayed impaired glycogen synthesis during the day and impaired nighttime survival. Thus, the pivotal role of c-di-AMP in day-night acclimation can be attributed to SbtB-mediated regulation of glycogen metabolism.
Collapse
Affiliation(s)
- Khaled A. Selim
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Corresponding author. (K.A.S.); (K.F.)
| | - Michael Haffner
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Markus Burkhardt
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Oliver Mantovani
- Plant Physiology Department, Institute of Biological Sciences, Rostock University, Rostock, Germany
| | - Niels Neumann
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Reinhard Albrecht
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Larissa Krüger
- Department of General Microbiology, Göttingen Center for Molecular Biosciences (GZMB), Göttingen University, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Göttingen Center for Molecular Biosciences (GZMB), Göttingen University, Göttingen, Germany
| | - Marcus D. Hartmann
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, Rostock University, Rostock, Germany
| | - Karl Forchhammer
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
- Corresponding author. (K.A.S.); (K.F.)
| |
Collapse
|
16
|
Lucius S, Makowka A, Michl K, Gutekunst K, Hagemann M. The Entner-Doudoroff Pathway Contributes to Glycogen Breakdown During High to Low CO 2 Shifts in the Cyanobacterium Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2021; 12:787943. [PMID: 34956285 PMCID: PMC8698341 DOI: 10.3389/fpls.2021.787943] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/12/2021] [Indexed: 06/12/2023]
Abstract
Cyanobacteria perform plant-like oxygenic photosynthesis to convert inorganic carbon into organic compounds and can also use internal carbohydrate reserves under specific conditions. A mutant collection with defects in different routes for sugar catabolism was studied to analyze which of them is preferentially used to degrade glycogen reserves in light-exposed cells of Synechocystis sp. PCC 6803 shifted from high to low CO2 conditions. Mutants defective in the glycolytic Embden-Meyerhof-Parnas pathway or in the oxidative pentose-phosphate (OPP) pathway showed glycogen levels similar to wild type under high CO2 (HC) conditions and were able to degrade it similarly after shifts to low CO2 (LC) conditions. In contrast, the mutant Δeda, which is defective in the glycolytic Entner-Doudoroff (ED) pathway, accumulated elevated glycogen levels under HC that were more slowly consumed during the LC shift. In consequence, the mutant Δeda showed a lowered ability to respond to the inorganic carbon shifts, displayed a pronounced lack in the reactivation of growth when brought back to HC, and differed significantly in its metabolite composition. Particularly, Δeda accumulated enhanced levels of proline, which is a well-known metabolite to maintain redox balances via NADPH levels in many organisms under stress conditions. We suggest that deletion of eda might promote the utilization of the OPP shunt that dramatically enhance NADPH levels. Collectively, the results point at a major regulatory contribution of the ED pathway for the mobilization of glycogen reserves during rapid acclimation to fluctuating CO2 conditions.
Collapse
Affiliation(s)
- Stefan Lucius
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Alexander Makowka
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany
| | - Klaudia Michl
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany
- Department of Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
- Interdisciplinary Faculty, Department Life, Light and Matter, University of Rostock, Rostock, Germany
| |
Collapse
|
17
|
Shabestary K, Hernández HP, Miao R, Ljungqvist E, Hallman O, Sporre E, Branco Dos Santos F, Hudson EP. Cycling between growth and production phases increases cyanobacteria bioproduction of lactate. Metab Eng 2021; 68:131-141. [PMID: 34601120 DOI: 10.1016/j.ymben.2021.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/03/2021] [Accepted: 09/25/2021] [Indexed: 01/23/2023]
Abstract
Decoupling growth from product synthesis is a promising strategy to increase carbon partitioning and maximize productivity in cell factories. However, reduction in both substrate uptake rate and metabolic activity in the production phase are an underlying problem for upscaling. Here, we used CRISPR interference to repress growth in lactate-producing Synechocystis sp. PCC 6803. Carbon partitioning to lactate in the production phase exceeded 90%, but CO2 uptake was severely reduced compared to uptake during the growth phase. We characterized strains during the onset of growth arrest using transcriptomics and proteomics. Multiple genes involved in ATP homeostasis were regulated once growth was inhibited, which suggests an alteration of energy charge that may lead to reduced substrate uptake. In order to overcome the reduced metabolic activity and take advantage of increased carbon partitioning, we tested a novel production strategy that involved alternating growth arrest and recovery by periodic addition of an inducer molecule to activate CRISPRi. Using this strategy, we maintained lactate biosynthesis in Synechocystis for 30 days in a constant light turbidostat cultivation. Cumulative lactate titers were also increased by 100% compared to a constant growth-arrest regime, and reached 1 g/L. Further, the cultivation produced lactate for 30 days, compared to 20 days for the non-growth arrest cultivation. Periodic growth arrest could be applicable for other products, and in cyanobacteria, could be linked to internal circadian rhythms that persist in constant light.
Collapse
Affiliation(s)
- Kiyan Shabestary
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Hugo Pineda Hernández
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Rui Miao
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Emil Ljungqvist
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Olivia Hallman
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Emil Sporre
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Filipe Branco Dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Elton P Hudson
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden.
| |
Collapse
|
18
|
Garg R, Maldener I. The Formation of Spore-Like Akinetes: A Survival Strategy of Filamentous Cyanobacteria. Microb Physiol 2021; 31:296-305. [PMID: 34482304 DOI: 10.1159/000517443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/26/2021] [Indexed: 11/19/2022]
Abstract
Some cyanobacteria of the order Nostocales can form akinetes, spore-like dormant cells resistant to various unfavorable environmental fluctuations. Akinetes are larger than vegetative cells and contain large quantities of reserve products, mainly glycogen and the nitrogen storage polypeptide polymer cyanophycin. Akinetes are enveloped in a thick protective coat containing a multilayered structure and are able to germinate into new vegetative cells under suitable growth conditions. Here, we summarize the significant morphological and physiological changes that occur during akinete differentiation and germination and present our investigation of the physiological function of the storage polymer cyanophycin in these cellular processes. We show that the cyanophycin production is not required for formation and germination of the akinetes in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.
Collapse
Affiliation(s)
- Ritu Garg
- Institute of Microbiology and Infection Medicine, Organismic Interactions, University of Tübingen, Tübingen, Germany
| | - Iris Maldener
- Institute of Microbiology and Infection Medicine, Organismic Interactions, University of Tübingen, Tübingen, Germany
| |
Collapse
|
19
|
Jacobson TB, Callaghan MM, Amador-Noguez D. Hostile Takeover: How Viruses Reprogram Prokaryotic Metabolism. Annu Rev Microbiol 2021; 75:515-539. [PMID: 34348026 DOI: 10.1146/annurev-micro-060621-043448] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To reproduce, prokaryotic viruses must hijack the cellular machinery of their hosts and redirect it toward the production of viral particles. While takeover of the host replication and protein synthesis apparatus has long been considered an essential feature of infection, recent studies indicate that extensive reprogramming of host primary metabolism is a widespread phenomenon among prokaryotic viruses that is required to fulfill the biosynthetic needs of virion production. In this review we provide an overview of the most significant recent findings regarding virus-induced reprogramming of prokaryotic metabolism and suggest how quantitative systems biology approaches may be used to provide a holistic understanding of metabolic remodeling during lytic viral infection. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Tyler B Jacobson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; , , .,Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Melanie M Callaghan
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; , , .,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; , , .,Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
20
|
Kondo K, Izumi M, Inabe K, Yoshida K, Imashimizu M, Suzuki T, Hisabori T. The phototroph-specific β-hairpin structure of the γ subunit of F oF 1-ATP synthase is important for efficient ATP synthesis of cyanobacteria. J Biol Chem 2021; 297:101027. [PMID: 34339736 PMCID: PMC8390522 DOI: 10.1016/j.jbc.2021.101027] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/26/2021] [Accepted: 07/29/2021] [Indexed: 12/01/2022] Open
Abstract
The FoF1 synthase produces ATP from ADP and inorganic phosphate. The γ subunit of FoF1 ATP synthase in photosynthetic organisms, which is the rotor subunit of this enzyme, contains a characteristic β-hairpin structure. This structure is formed from an insertion sequence that has been conserved only in phototrophs. Using recombinant subcomplexes, we previously demonstrated that this region plays an essential role in the regulation of ATP hydrolysis activity, thereby functioning in controlling intracellular ATP levels in response to changes in the light environment. However, the role of this region in ATP synthesis has long remained an open question because its analysis requires the preparation of the whole FoF1 complex and a transmembrane proton-motive force. In this study, we successfully prepared proteoliposomes containing the entire FoF1 ATP synthase from a cyanobacterium, Synechocystis sp. PCC 6803, and measured ATP synthesis/hydrolysis and proton-translocating activities. The relatively simple genetic manipulation of Synechocystis enabled the biochemical investigation of the role of the β-hairpin structure of FoF1 ATP synthase and its activities. We further performed physiological analyses of Synechocystis mutant strains lacking the β-hairpin structure, which provided novel insights into the regulatory mechanisms of FoF1 ATP synthase in cyanobacteria via the phototroph-specific region of the γ subunit. Our results indicated that this structure critically contributes to ATP synthesis and suppresses ATP hydrolysis.
Collapse
Affiliation(s)
- Kumiko Kondo
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Masayuki Izumi
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Kosuke Inabe
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Keisuke Yoshida
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Mari Imashimizu
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Toshiharu Suzuki
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan.
| |
Collapse
|
21
|
Schada von Borzyskowski L, Bernhardsgrütter I, Erb TJ. Biochemical unity revisited: microbial central carbon metabolism holds new discoveries, multi-tasking pathways, and redundancies with a reason. Biol Chem 2021; 401:1429-1441. [PMID: 32990641 DOI: 10.1515/hsz-2020-0214] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 09/10/2020] [Indexed: 01/27/2023]
Abstract
For a long time, our understanding of metabolism has been dominated by the idea of biochemical unity, i.e., that the central reaction sequences in metabolism are universally conserved between all forms of life. However, biochemical research in the last decades has revealed a surprising diversity in the central carbon metabolism of different microorganisms. Here, we will embrace this biochemical diversity and explain how genetic redundancy and functional degeneracy cause the diversity observed in central metabolic pathways, such as glycolysis, autotrophic CO2 fixation, and acetyl-CoA assimilation. We conclude that this diversity is not the exception, but rather the standard in microbiology.
Collapse
Affiliation(s)
- Lennart Schada von Borzyskowski
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043Marburg, Germany
| | - Iria Bernhardsgrütter
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043Marburg, Germany
| | - Tobias J Erb
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043Marburg, Germany.,Center for Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, D-35043Marburg, Germany
| |
Collapse
|
22
|
Koch M, Forchhammer K. Polyhydroxybutyrate: A Useful Product of Chlorotic Cyanobacteria. Microb Physiol 2021; 31:67-77. [PMID: 33979794 DOI: 10.1159/000515617] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/02/2021] [Indexed: 11/19/2022]
Abstract
Polyhydroxybutyrate (PHB) is a carbon polymer with diverse functions, varying greatly on the organism producing it. This microreview describes the current knowledge about PHB metabolism, structure, and different physiological roles with a special focus on cyanobacteria. Despite the physiological function of PHB in the cyanobacterial phylum still being unknown, these organisms provide the unique opportunity to directly convert atmospheric CO2 into bioplastic using a solar-based process. Recent research on PHB metabolism in the cyanobacterial model organism Synechocystis revealed a sophisticated control of PHB granule formation. Novel insights about the metabolic background of PHB synthesis resulted in the engineering of the first cyanobacterial superproducer strain.
Collapse
Affiliation(s)
- Moritz Koch
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| |
Collapse
|
23
|
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.
Collapse
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.)
| |
Collapse
|
24
|
Neumann N, Doello S, Forchhammer K. Recovery of Unicellular Cyanobacteria from Nitrogen Chlorosis: A Model for Resuscitation of Dormant Bacteria. Microb Physiol 2021; 31:78-87. [PMID: 33878759 DOI: 10.1159/000515742] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/06/2021] [Indexed: 11/19/2022]
Abstract
Nitrogen starvation induces developmental transitions in cyanobacteria. Whereas complex multicellular cyanobacteria of the order Nostocales can differentiate specialized cells that perform nitrogen fixation in the presence of oxygenic photosynthesis, non-diazotrophic unicellular strains, such as Synechococcus elongatus or Synechocystis PCC 6803, undergo a transition into a dormant non-growing state. Due to loss of pigments during this acclimation, the process is termed chlorosis. Cells maintain viability in this state for prolonged periods of time, until they encounter a useable nitrogen source, which triggers a highly coordinated awakening process, termed resuscitation. The minimal set of cellular activity that maintains the viability of cells during chlorosis and ensures efficient resuscitation represents the organism's equivalent of the BIOS, the basic input/output system of a computer, that helps "booting" the operation system after switching on. This review summarizes the recent research in the resuscitation of cyanobacteria, representing a powerful model for the awakening of dormant bacteria.
Collapse
Affiliation(s)
- Niels Neumann
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Sofia Doello
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| |
Collapse
|
25
|
Iijima H, Watanabe A, Sukigara H, Iwazumi K, Shirai T, Kondo A, Osanai T. Four-carbon dicarboxylic acid production through the reductive branch of the open cyanobacterial tricarboxylic acid cycle in Synechocystis sp. PCC 6803. Metab Eng 2021; 65:88-98. [PMID: 33722652 DOI: 10.1016/j.ymben.2021.03.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 02/23/2021] [Accepted: 03/06/2021] [Indexed: 11/18/2022]
Abstract
Succinate, fumarate, and malate are valuable four-carbon (C4) dicarboxylic acids used for producing plastics and food additives. C4 dicarboxylic acid is biologically produced by heterotrophic organisms. However, current biological production requires organic carbon sources that compete with food uses. Herein, we report C4 dicarboxylic acid production from CO2 using metabolically engineered Synechocystis sp. PCC 6803. Overexpression of citH, encoding malate dehydrogenase (MDH), resulted in the enhanced production of succinate, fumarate, and malate. citH overexpression increased the reductive branch of the open cyanobacterial tricarboxylic acid (TCA) cycle flux. Furthermore, product stripping by medium exchanges increased the C4 dicarboxylic acid levels; product inhibition and acidification of the media were the limiting factors for succinate production. Our results demonstrate that MDH is a key regulator that activates the reductive branch of the open cyanobacterial TCA cycle. The study findings suggest that cyanobacteria can act as a biocatalyst for converting CO2 to carboxylic acids.
Collapse
Affiliation(s)
- Hiroko Iijima
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Atsuko Watanabe
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Haruna Sukigara
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Kaori Iwazumi
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Tomokazu Shirai
- Center for Sustainable Resource Science, RIKEN, 1-7-22, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Akihiko Kondo
- Center for Sustainable Resource Science, RIKEN, 1-7-22, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan; Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Takashi Osanai
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan.
| |
Collapse
|
26
|
Doello S, Burkhardt M, Forchhammer K. The essential role of sodium bioenergetics and ATP homeostasis in the developmental transitions of a cyanobacterium. Curr Biol 2021; 31:1606-1615.e2. [PMID: 33571435 DOI: 10.1016/j.cub.2021.01.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/30/2020] [Accepted: 01/19/2021] [Indexed: 10/22/2022]
Abstract
The ability to resume growth after a dormant period is an important strategy for the survival and spreading of bacterial populations. Energy homeostasis is critical in the transition into and out of a quiescent state. Synechocystis sp. PCC 6803, a non-diazotrophic cyanobacterium, enters metabolic dormancy as a response to nitrogen starvation. We used Synechocystis as a model to investigate the regulation of ATP homeostasis during dormancy, and we unraveled a critical role for sodium bioenergetics in dormant cells. During nitrogen starvation, cells reduce their ATP levels and engage sodium bioenergetics to maintain the minimum ATP content required for viability. When nitrogen becomes available, energy requirements rise, and cells immediately increase ATP levels, employing sodium bioenergetics and glycogen catabolism. These processes allow them to restore the photosynthetic machinery and resume photoautotrophic growth. Our work reveals a precise regulation of the energy metabolism essential for bacterial survival during periods of nutrient deprivation.
Collapse
Affiliation(s)
- Sofia Doello
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Markus Burkhardt
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
| |
Collapse
|
27
|
Orthwein T, Scholl J, Spät P, Lucius S, Koch M, Macek B, Hagemann M, Forchhammer K. The novel P II-interactor PirC identifies phosphoglycerate mutase as key control point of carbon storage metabolism in cyanobacteria. Proc Natl Acad Sci U S A 2021; 118:e2019988118. [PMID: 33526690 PMCID: PMC8018021 DOI: 10.1073/pnas.2019988118] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nitrogen limitation imposes a major transition in the lifestyle of nondiazotrophic cyanobacteria that is controlled by a complex interplay of regulatory factors involving the pervasive signal processor PII Immediately upon nitrogen limitation, newly fixed carbon is redirected toward glycogen synthesis. How the metabolic switch for diverting fixed carbon toward the synthesis of glycogen or of cellular building blocks is operated was so far poorly understood. Here, using the nondiazotrophic cyanobacterium Synechocystis sp. PCC 6803 as model system, we identified a novel PII interactor, the product of the sll0944 gene, which we named PirC. We show that PirC binds to and inhibits the activity of 2,3-phosphoglycerate-independent phosphoglycerate mutase (PGAM), the enzyme that deviates newly fixed CO2 toward lower glycolysis. The binding of PirC to either PII or PGAM is tuned by the metabolite 2-oxoglutarate (2-OG), which accumulates upon nitrogen starvation. In these conditions, the high levels of 2-OG dissociate the PirC-PII complex to promote PirC binding to and inhibition of PGAM. Accordingly, a PirC-deficient mutant showed strongly reduced glycogen levels upon nitrogen deprivation, whereas polyhydroxybutyrate granules were overaccumulated compared to wild-type. Metabolome analysis revealed an imbalance in 3-phosphoglycerate to pyruvate levels in the pirC mutant, confirming that PirC controls the carbon flux in cyanobacteria via mutually exclusive interaction with either PII or PGAM.
Collapse
Affiliation(s)
- Tim Orthwein
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Jörg Scholl
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp Spät
- Department of Quantitative Proteomics, University of Tübingen, 72076 Tübingen, Germany
| | - Stefan Lucius
- Institute of Biological Sciences, Plant Physiology Department, University of Rostock, 18059 Rostock, Germany
| | - Moritz Koch
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany
| | - Boris Macek
- Department of Quantitative Proteomics, University of Tübingen, 72076 Tübingen, Germany
| | - Martin Hagemann
- Institute of Biological Sciences, Plant Physiology Department, University of Rostock, 18059 Rostock, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany;
| |
Collapse
|
28
|
Koch M, Bruckmoser J, Scholl J, Hauf W, Rieger B, Forchhammer K. Maximizing PHB content in Synechocystis sp. PCC 6803: a new metabolic engineering strategy based on the regulator PirC. Microb Cell Fact 2020; 19:231. [PMID: 33353555 PMCID: PMC7756911 DOI: 10.1186/s12934-020-01491-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/02/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PHB (poly-hydroxy-butyrate) represents a promising bioplastic alternative with good biodegradation properties. Furthermore, PHB can be produced in a completely carbon-neutral fashion in the natural producer cyanobacterium Synechocystis sp. PCC 6803. This strain has been used as model system in past attempts to boost the intracellular production of PHB above ~ 15% per cell-dry-weight (CDW). RESULTS We have created a new strain that lacks the regulatory protein PirC (product of sll0944), which exhibits a higher activity of the phosphoglycerate mutase resulting in increased PHB pools under nutrient limiting conditions. To further improve the intracellular PHB content, two genes involved in PHB metabolism, phaA and phaB, from the known producer strain Cupriavidus necator, were introduced under the control of the strong promotor PpsbA2. The resulting strain, termed PPT1 (ΔpirC-REphaAB), produced high amounts of PHB under continuous light as well under a day-night regime. When grown in nitrogen and phosphorus depleted medium, the cells produced up to 63% per CDW. Upon the addition of acetate, the content was further increased to 81% per CDW. The produced polymer consists of pure PHB, which is highly isotactic. CONCLUSION The amounts of PHB achieved with PPT1 are the highest ever reported in any known cyanobacterium and demonstrate the potential of cyanobacteria for a sustainable, industrial production of PHB.
Collapse
Affiliation(s)
- Moritz Koch
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Jonas Bruckmoser
- Wacker-Chair of Macromolecular Chemistry, TUM Department of Chemistry, Technical University of Munich, Munich, Germany
| | - Jörg Scholl
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Waldemar Hauf
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Bernhard Rieger
- Wacker-Chair of Macromolecular Chemistry, TUM Department of Chemistry, Technical University of Munich, Munich, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
| |
Collapse
|
29
|
Theune ML, Hildebrandt S, Steffen-Heins A, Bilger W, Gutekunst K, Appel J. In-vivo quantification of electron flow through photosystem I - Cyclic electron transport makes up about 35% in a cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148353. [PMID: 33346012 DOI: 10.1016/j.bbabio.2020.148353] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/15/2022]
Abstract
Photosynthetic electron flow, driven by photosystem I and II, provides chemical energy for carbon fixation. In addition to a linear mode a second cyclic route exists, which only involves photosystem I. The exact contributions of linear and cyclic transport are still a matter of debate. Here, we describe the development of a method that allows quantification of electron flow in absolute terms through photosystem I in a photosynthetic organism for the first time. Specific in-vivo protocols allowed to discern the redox states of plastocyanin, P700 and the FeS-clusters including ferredoxin at the acceptor site of PSI in the cyanobacterium Synechocystis sp. PCC 6803 with the near-infrared spectrometer Dual-KLAS/NIR. P700 absorbance changes determined with the Dual-KLAS/NIR correlated linearly with direct determinations of PSI concentrations using EPR. Dark-interval relaxation kinetics measurements (DIRKPSI) were applied to determine electron flow through PSI. Counting electrons from hydrogen oxidation as electron donor to photosystem I in parallel to DIRKPSI measurements confirmed the validity of the method. Electron flow determination by classical PSI yield measurements overestimates electron flow at low light intensities and saturates earlier compared to DIRKPSI. Combination of DIRKPSI with oxygen evolution measurements yielded a proportion of 35% of surplus electrons passing PSI compared to PSII. We attribute these electrons to cyclic electron transport, which is twice as high as assumed for plants. Counting electrons flowing through the photosystems allowed determination of the number of quanta required for photosynthesis to 11 per oxygen produced, which is close to published values.
Collapse
Affiliation(s)
- Marius L Theune
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Sarah Hildebrandt
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Anja Steffen-Heins
- Division of Food Technology, Institute of Human Nutrition and Food Science, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Wolfgang Bilger
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Jens Appel
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany.
| |
Collapse
|
30
|
Chuang DSW, Liao JC. Role of cyanobacterial phosphoketolase in energy regulation and glucose secretion under dark anaerobic and osmotic stress conditions. Metab Eng 2020; 65:255-262. [PMID: 33326847 DOI: 10.1016/j.ymben.2020.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/20/2020] [Accepted: 12/06/2020] [Indexed: 01/10/2023]
Abstract
Primary metabolism in cyanobacteria is built on the Calvin-Benson-Bassham (CBB) cycle, oxidative pentose phosphate (OPP) pathway, Embden-Meyerhof-Parnas (EMP) pathway, and the tricarboxylic acid (TCA) cycle. Phosphoketolase (Xpk), commonly found in cyanobacteria, is an enzyme that is linked to all these pathways. However, little is known about its physiological role. Here, we show that most of the cyanobacterial Xpk surveyed are inhibited by ATP, and both copies of Xpk in nitrogen-fixing Cyanothece ATCC51142 are further activated by ADP, suggesting their role in energy regulation. Moreover, Xpk in Synechococcus elongatus PCC7942 and Cyanothece ATCC51142 show that their expressions are dusk-peaked, suggesting their roles in dark conditions. Finally, we find that Xpk in S. elongatus PCC7942 is responsible for survival using ATP produced from the glycogen-to-acetate pathway under dark, anaerobic condition. Interestingly, under this condition, xpk deletion causes glucose secretion in response to osmotic shock such as NaHCO3, KHCO3 and NaCl as part of incomplete glycogen degradation. These findings unveiled the role of this widespread enzyme and open the possibility for enhanced glucose secretion from cyanobacteria.
Collapse
Affiliation(s)
- Derrick Shih-Wei Chuang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, USA
| | - James C Liao
- Institute of Biological Chemistry, Academia Sinica, Taiwan.
| |
Collapse
|
31
|
Selim KA, Haffner M. Heavy Metal Stress Alters the Response of the Unicellular Cyanobacterium Synechococcus elongatus PCC 7942 to Nitrogen Starvation. Life (Basel) 2020; 10:life10110275. [PMID: 33171751 PMCID: PMC7694984 DOI: 10.3390/life10110275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 01/10/2023] Open
Abstract
Non-diazotrophic cyanobacteria are unable to fix atmospheric nitrogen and rely on combined nitrogen for growth and development. In the absence of combined nitrogen sources, most non-diazotrophic cyanobacteria, e.g., Synechocystis sp. PCC 6803 or Synechococcus elongatus PCC 7942, enter a dormant stage called chlorosis. The chlorosis process involves switching off photosynthetic activities and downregulating protein biosynthesis. Addition of a combined nitrogen source induces the regeneration of chlorotic cells in a process called resuscitation. As heavy metals are ubiquitous in the cyanobacterial biosphere, their influence on the vegetative growth of cyanobacterial cells has been extensively studied. However, the effect of heavy metal stress on chlorotic cyanobacterial cells remains elusive. To simulate the natural conditions, we investigated the effects of long-term exposure of S. elongatus PCC 7942 cells to both heavy metal stress and nitrogen starvation. We were able to show that elevated heavy metal concentrations, especially for Ni2+, Cd2+, Cu2+ and Zn2+, are highly toxic to nitrogen starved cells. In particular, cells exposed to elevated concentrations of Cd2+ or Ni2+ were not able to properly enter chlorosis as they failed to degrade phycobiliproteins and chlorophyll a and remained greenish. In resuscitation assays, these cells were unable to recover from the simultaneous nitrogen starvation and Cd2+ or Ni2+ stress. The elevated toxicity of Cd2+ or Ni2+ presumably occurs due to their interference with the onset of chlorosis in nitrogen-starved cells, eventually leading to cell death.
Collapse
|
32
|
Forchhammer K, Selim KA. Carbon/nitrogen homeostasis control in cyanobacteria. FEMS Microbiol Rev 2020; 44:33-53. [PMID: 31617886 PMCID: PMC8042125 DOI: 10.1093/femsre/fuz025] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/14/2019] [Indexed: 02/06/2023] Open
Abstract
Carbon/nitrogen (C/N) balance sensing is a key requirement for the maintenance of cellular homeostasis. Therefore, cyanobacteria have evolved a sophisticated signal transduction network targeting the metabolite 2-oxoglutarate (2-OG), the carbon skeleton for nitrogen assimilation. It serves as a status reporter for the cellular C/N balance that is sensed by transcription factors NtcA and NdhR and the versatile PII-signaling protein. The PII protein acts as a multitasking signal-integrating regulator, combining the 2-OG signal with the energy state of the cell through adenyl-nucleotide binding. Depending on these integrated signals, PII orchestrates metabolic activities in response to environmental changes through binding to various targets. In addition to 2-OG, other status reporter metabolites have recently been discovered, mainly indicating the carbon status of the cells. One of them is cAMP, which is sensed by the PII-like protein SbtB. The present review focuses, with a main emphasis on unicellular model strains Synechoccus elongatus and Synechocystis sp. PCC 6803, on the physiological framework of these complex regulatory loops, the tight linkage to metabolism and the molecular mechanisms governing the signaling processes.
Collapse
Affiliation(s)
- Karl Forchhammer
- Lehrstuhl für Mikrobiologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
| | - Khaled A Selim
- Lehrstuhl für Mikrobiologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
| |
Collapse
|
33
|
Cyanobacterial sigma factors: Current and future applications for biotechnological advances. Biotechnol Adv 2020; 40:107517. [DOI: 10.1016/j.biotechadv.2020.107517] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 11/15/2022]
|
34
|
Koch M, Orthwein T, Alford JT, Forchhammer K. The Slr0058 Protein From Synechocystis sp. PCC 6803 Is a Novel Regulatory Protein Involved in PHB Granule Formation. Front Microbiol 2020; 11:809. [PMID: 32425918 PMCID: PMC7203880 DOI: 10.3389/fmicb.2020.00809] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
During phases of nitrogen starvation, the photosynthetic cyanobacterium Synechocystis sp. PCC 6803 produces polyhydroxybutyrate (PHB). This polymer is of high biotechnological relevance because of its potential as biodegradable plastic. Analysis of the Synechocystis genome revealed an operon (slr0058-slr0061) containing several genes, which are putatively related to the PHB metabolism. While Slr0058 show similarities with the regulatory phasin PhaF, the protein Slr0060 could serve as an intracellular PHB depolymerase. Investigation of respective knock-out mutants showed no distinct phenotype for the strain lacking Slr0060, whereas the Δslr0058 mutant displayed a growth impairment as well as a change in pigmentation. During nitrogen starvation, the Δslr0058 mutant produced in average more than twice the amount of PHB granules per cell, while the overall amount of PHB remained the same. This indicates that Slr0058 plays a role in PHB granule formation and controls it surface-to-volume ratio. GFP-tagged Slr0058 did not co-localize with PHB granules during nitrogen starvation but aggregated in distinct foci during vegetative growth. This work helps to better understand the PHB metabolism of Synechocystis sp. PCC 6803, coming closer to a sustainable, industrial production of PHB.
Collapse
Affiliation(s)
- Moritz Koch
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Tim Orthwein
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Janette T Alford
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
| |
Collapse
|
35
|
Kobayashi K, Osawa Y, Yoshihara A, Shimojima M, Awai K. Relationship Between Glycerolipids and Photosynthetic Components During Recovery of Thylakoid Membranes From Nitrogen Starvation-Induced Attenuation in Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2020; 11:432. [PMID: 32351534 PMCID: PMC7175274 DOI: 10.3389/fpls.2020.00432] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
Thylakoid membranes, the site of photochemical and electron transport reactions of oxygenic photosynthesis, are composed of a myriad of proteins, cofactors including pigments, and glycerolipids. In the non-diazotrophic cyanobacterium Synechocystis sp. PCC 6803, the size and function of thylakoid membranes are reduced under nitrogen (N) starvation but are quickly recovered after N addition to the starved cells. To understand how the functionality of thylakoid membranes is adjusted in response to N status in Synechocystis sp. PCC 6803, we examined changes in thylakoid components and the photosynthetic activity during the N starvation and recovery processes. In N-starved cells, phycobilisome content, photosystem II protein levels and the photosynthetic activity substantially decreased as compared with those in N-sufficient cells. Although the content of chlorophyll (Chl) a, total protein and total glycerolipid also decreased under the N-starved condition based on OD730 reflecting cell density, when based on culture volume, the Chl a and total protein content remained almost constant and total glycerolipid content even increased during N starvation, suggesting that cellular levels of these components decrease under the N-starved condition mainly through dilution due to cell growth. With N addition, the photosynthetic activity quickly recovered, followed by full restoration of photosynthetic pigment and protein levels. The content of phosphatidylglycerol (PG), an essential lipid constituent of both photosystems, increased faster than that of Chl a, whereas the content of glycolipids, the main constituents of the thylakoid lipid bilayer, gradually recovered after N addition. The data indicate differential regulation of PG and glycolipids during the construction of the photosynthetic machinery and regeneration of thylakoid membranes. Of note, addition of PG to the growth medium slightly accelerated the Chl a accumulation in wild-type cells during the recovery process. Because PG is required for the biosynthesis of Chl a and the formation of functional photosystem complexes, rapid PG biosynthesis in response to N acquisition may be required for the rapid formation of the photosynthetic machinery during thylakoid regeneration.
Collapse
Affiliation(s)
- Koichi Kobayashi
- Faculty of Liberal Arts and Sciences, Osaka Prefecture University, Sakai, Japan
| | - Yuka Osawa
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka, Japan
| | - Akiko Yoshihara
- Department of Biological Sciences, School of Science, Osaka Prefecture University, Sakai, Japan
| | - Mie Shimojima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Koichiro Awai
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka, Japan
- Research Institute of Electronics, Shizuoka University, Hamamatsu, Japan
| |
Collapse
|
36
|
Makowka A, Nichelmann L, Schulze D, Spengler K, Wittmann C, Forchhammer K, Gutekunst K. Glycolytic Shunts Replenish the Calvin-Benson-Bassham Cycle as Anaplerotic Reactions in Cyanobacteria. MOLECULAR PLANT 2020; 13:471-482. [PMID: 32044444 DOI: 10.1016/j.molp.2020.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/16/2019] [Accepted: 01/10/2020] [Indexed: 05/07/2023]
Abstract
The recent discovery of the Entner-Doudoroff (ED) pathway as a third glycolytic route beside Embden-Meyerhof-Parnas (EMP) and oxidative pentose phosphate (OPP) pathway in oxygenic photoautotrophs requires a revision of their central carbohydrate metabolism. In this study, unexpectedly, we observed that deletion of the ED pathway alone, and even more pronounced in combination with other glycolytic routes, diminished photoautotrophic growth in continuous light in the cyanobacterium Synechocystis sp. PCC 6803. Furthermore, we found that the ED pathway is required for optimal glycogen catabolism in parallel to an operating Calvin-Benson-Bassham (CBB) cycle. It is counter-intuitive that glycolytic routes, which are a reverse to the CBB cycle and do not provide any additional biosynthetic intermediates, are important under photoautotrophic conditions. However, observations on the ability to reactivate an arrested CBB cycle revealed that they form glycolytic shunts that tap the cellular carbohydrate reservoir to replenish the cycle. Taken together, our results suggest that the classical view of the CBB cycle as an autocatalytic, completely autonomous cycle that exclusively relies on its own enzymes and CO2 fixation to regenerate ribulose-1,5-bisphosphate for Rubisco is an oversimplification. We propose that in common with other known autocatalytic cycles, the CBB cycle likewise relies on anaplerotic reactions to compensate for the depletion of intermediates, particularly in transition states and under fluctuating light conditions that are common in nature.
Collapse
Affiliation(s)
- Alexander Makowka
- Department of Biology, Botanical Institute, University Kiel, 24118 Kiel, Germany
| | - Lars Nichelmann
- Department of Biology, Botanical Institute, University Kiel, 24118 Kiel, Germany
| | - Dennis Schulze
- Institute for Systems Biotechnology, Saarland University, 66123 Saarbrücken, Germany
| | - Katharina Spengler
- Department of Biology, Botanical Institute, University Kiel, 24118 Kiel, Germany
| | - Christoph Wittmann
- Institute for Systems Biotechnology, Saarland University, 66123 Saarbrücken, Germany
| | - Karl Forchhammer
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, University Tübingen, 72076 Tübingen, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, University Kiel, 24118 Kiel, Germany.
| |
Collapse
|
37
|
Shinde S, Zhang X, Singapuri SP, Kalra I, Liu X, Morgan-Kiss RM, Wang X. Glycogen Metabolism Supports Photosynthesis Start through the Oxidative Pentose Phosphate Pathway in Cyanobacteria. PLANT PHYSIOLOGY 2020; 182:507-517. [PMID: 31649110 PMCID: PMC6945877 DOI: 10.1104/pp.19.01184] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 10/17/2019] [Indexed: 06/07/2023]
Abstract
Cyanobacteria experience drastic changes in their carbon metabolism under daily light/dark cycles. During the day, the Calvin-Benson cycle fixes CO2 and diverts excess carbon into glycogen storage. At night, glycogen is degraded to support cellular respiration. The dark/light transition represents a universal environmental stress for cyanobacteria and other photosynthetic lifeforms. Recent studies revealed the essential genetic background necessary for the fitness of cyanobacteria during diurnal growth. However, the metabolic processes underlying the dark/light transition are not well understood. In this study, we observed that glycogen metabolism supports photosynthesis in the cyanobacterium Synechococcus elongatus PCC 7942 when photosynthesis reactions start upon light exposure. Compared with the wild type, the glycogen mutant ∆glgC showed a reduced photosynthetic efficiency and a slower P700+ rereduction rate when photosynthesis starts. Proteomic analyses indicated that glycogen is degraded through the oxidative pentose phosphate (OPP) pathway during the dark/light transition. We confirmed that the OPP pathway is essential for the initiation of photosynthesis and further showed that glycogen degradation through the OPP pathway contributes to the activation of key Calvin-Benson cycle enzymes by modulating NADPH levels. This strategy stimulates photosynthesis in cyanobacteria following dark respiration and stabilizes the Calvin-Benson cycle under fluctuating environmental conditions, thereby offering evolutionary advantages for photosynthetic organisms using the Calvin-Benson cycle for carbon fixation.
Collapse
Affiliation(s)
- Shrameeta Shinde
- Department of Microbiology, Miami University, Oxford, Ohio 45056
| | - Xiaohui Zhang
- Department of Microbiology, Miami University, Oxford, Ohio 45056
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300354, China
| | | | - Isha Kalra
- Department of Microbiology, Miami University, Oxford, Ohio 45056
| | - Xianhua Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300354, China
| | | | - Xin Wang
- Department of Microbiology, Miami University, Oxford, Ohio 45056
| |
Collapse
|
38
|
PHB is Produced from Glycogen Turn-over during Nitrogen Starvation in Synechocystis sp. PCC 6803. Int J Mol Sci 2019; 20:ijms20081942. [PMID: 31010017 PMCID: PMC6514691 DOI: 10.3390/ijms20081942] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 12/17/2022] Open
Abstract
Polyhydroxybutyrate (PHB) is a polymer of great interest as a substitute for conventional plastics, which are becoming an enormous environmental problem. PHB can be produced directly from CO2 in photoautotrophic cyanobacteria. The model cyanobacterium Synechocystis sp. PCC 6803 produces PHB under conditions of nitrogen starvation. However, it is so far unclear which metabolic pathways provide the precursor molecules for PHB synthesis during nitrogen starvation. In this study, we investigated if PHB could be derived from the main intracellular carbon pool, glycogen. A mutant of the major glycogen phosphorylase, GlgP2 (slr1367 product), was almost completely impaired in PHB synthesis. Conversely, in the absence of glycogen synthase GlgA1 (sll0945 product), cells not only produced less PHB, but were also impaired in acclimation to nitrogen depletion. To analyze the role of the various carbon catabolic pathways (EMP, ED and OPP pathways) for PHB production, mutants of key enzymes of these pathways were analyzed, showing different impact on PHB synthesis. Together, this study clearly indicates that PHB in glycogen-producing Synechocystis sp. PCC 6803 cells is produced from this carbon-pool during nitrogen starvation periods. This knowledge can be used for metabolic engineering to get closer to the overall goal of a sustainable, carbon-neutral bioplastic production.
Collapse
|
39
|
Xu HF, Dai GZ, Qiu BS. Weak red light plays an important role in awakening the photosynthetic machinery following desiccation in the subaerial cyanobacterium Nostoc flagelliforme. Environ Microbiol 2019; 21:2261-2272. [PMID: 30895692 DOI: 10.1111/1462-2920.14600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/31/2019] [Accepted: 03/19/2019] [Indexed: 11/28/2022]
Abstract
The subaerial cyanobacterium Nostoc flagelliforme can survive for years in the desiccated state and light exposure may stimulate photosynthetic recovery during rehydration. However, the influence of light quality on photosynthetic recovery and the underlying mechanism remain unresolved. Exposure of field collected N. flagelliforme to light intensity ≥2 μmol photons m-2 s-1 showed that the speed of photosystem II (PSII) recovery was in the following order: red > green > blue ≈ violet light. Decreasing the light intensity showed that weak red light stimulated PSII recovery during rehydration. The chlorophyll fluorescence transient and oxygen evolution activity indicated that the oxygen evolution complex (OEC) was the activated site triggered by weak red light. The damaged D1 protein accumulated in the thylakoid membrane during dehydration and is degraded and resynthesized during dark rehydration. PsbO interaction with the thylakoid membrane was induced by weak red light. Thus, weak red light plays an important role in triggering OEC photoactivation and the formation of functional PSII during rehydration. In its arid habitats, weak red light could stimulate the awakening of dormant N. flagelliforme after absorbing water from nighttime dew or rain to maximize growth during the early daylight hours of the dry season.
Collapse
Affiliation(s)
- Hai-Feng Xu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| | - Guo-Zheng Dai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| | - Bao-Sheng Qiu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| |
Collapse
|
40
|
Forchhammer K, Schwarz R. Nitrogen chlorosis in unicellular cyanobacteria – a developmental program for surviving nitrogen deprivation. Environ Microbiol 2018; 21:1173-1184. [DOI: 10.1111/1462-2920.14447] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, University Tübingen Auf der Morgenstelle 28, 72076 Tübingen Germany
| | - Rakefet Schwarz
- The Mina & Everard Goodman Faculty of Life SciencesBar‐Ilan University Ramat‐Gan 5290002 Israel
| |
Collapse
|
41
|
Forcada-Nadal A, Llácer JL, Contreras A, Marco-Marín C, Rubio V. The P II-NAGK-PipX-NtcA Regulatory Axis of Cyanobacteria: A Tale of Changing Partners, Allosteric Effectors and Non-covalent Interactions. Front Mol Biosci 2018; 5:91. [PMID: 30483512 PMCID: PMC6243067 DOI: 10.3389/fmolb.2018.00091] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/18/2018] [Indexed: 11/13/2022] Open
Abstract
PII, a homotrimeric very ancient and highly widespread (bacteria, archaea, plants) key sensor-transducer protein, conveys signals of abundance or poorness of carbon, energy and usable nitrogen, converting these signals into changes in the activities of channels, enzymes, or of gene expression. PII sensing is mediated by the PII allosteric effectors ATP, ADP (and, in some organisms, AMP), 2-oxoglutarate (2OG; it reflects carbon abundance and nitrogen scarcity) and, in many plants, L-glutamine. Cyanobacteria have been crucial for clarification of the structural bases of PII function and regulation. They are the subject of this review because the information gathered on them provides an overall structure-based view of a PII regulatory network. Studies on these organisms yielded a first structure of a PII complex with an enzyme, (N-acetyl-Lglutamate kinase, NAGK), deciphering how PII can cause enzyme activation, and how it promotes nitrogen stockpiling as arginine in cyanobacteria and plants. They have also revealed the first clear-cut mechanism by which PII can control gene expression. A small adaptor protein, PipX, is sequestered by PII when nitrogen is abundant and is released when is scarce, swapping partner by binding to the 2OG-activated transcriptional regulator NtcA, co-activating it. The structures of PII-NAGK, PII-PipX, PipX alone, of NtcA in inactive and 2OG-activated forms and as NtcA-2OG-PipX complex, explain structurally PII regulatory functions and reveal the changing shapes and interactions of the T-loops of PII depending on the partner and on the allosteric effectors bound to PII. Cyanobacterial studies have also revealed that in the PII-PipX complex PipX binds an additional transcriptional factor, PlmA, thus possibly expanding PipX roles beyond NtcA-dependency. Further exploration of these roles has revealed a functional interaction of PipX with PipY, a pyridoxal-phosphate (PLP) protein involved in PLP homeostasis whose mutations in the human ortholog cause epilepsy. Knowledge of cellular levels of the different components of this PII-PipX regulatory network and of KD values for some of the complexes provides the basic background for gross modeling of the system at high and low nitrogen abundance. The cyanobacterial network can guide searches for analogous components in other organisms, particularly of PipX functional analogs.
Collapse
Affiliation(s)
- Alicia Forcada-Nadal
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - José Luis Llácer
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Clara Marco-Marín
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| |
Collapse
|
42
|
Cyanophycin Synthesis Optimizes Nitrogen Utilization in the Unicellular Cyanobacterium Synechocystis sp. Strain PCC 6803. Appl Environ Microbiol 2018; 84:AEM.01298-18. [PMID: 30120117 DOI: 10.1128/aem.01298-18] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/09/2018] [Indexed: 11/20/2022] Open
Abstract
Cyanophycin is a carbon/nitrogen storage polymer widely distributed in most cyanobacterial strains and in a few heterotrophic bacteria. It is a nonribosomal polypeptide consisting of equimolar amounts of aspartate and arginine. Here, we focused on the physiological function and cell biology of cyanophycin in the unicellular nondiazotrophic cyanobacterium Synechocystis sp. strain PCC 6803. To study the cellular localization of the cyanophycin-synthesizing enzyme CphA during cyanophycin synthesis and degradation, we fused it to green fluorescent protein. When CphA was inactive, it localized diffusely in the cytoplasm. When cyanophycin synthesis was triggered, CphA first aggregated into foci and later localized on the surface of cyanophycin granules. In the corresponding cell extracts, localization of CphA on the cyanophycin granule surface required Mg2+ During cyanophycin degradation, CphA dissociated from the granule surface and returned to its inactive form in the cytoplasm. To investigate the physiological role of cyanophycin, we compared wild-type cells with a CphA-deficient mutant. Under standard laboratory conditions, the ability to synthesize cyanophycin did not confer a growth advantage. To mimic the situation in natural habitats, cells were cultured with a fluctuating and limiting nitrogen supplementation and/or day/night cycles. Under all of these conditions, cyanophycin provided a fitness advantage to the wild type over the mutant lacking cyanophycin. During resuscitation from nitrogen starvation, wild-type cells accumulated cyanophycin during the night and used it as an internal nitrogen source during the day. This demonstrates that cyanophycin can be used as a temporary nitrogen storage to uncouple nitrogen assimilation from photosynthesis.IMPORTANCE We clarified the elusive biological function of cyanophycin in the nondiazotrophic cyanobacterium Synechocystis sp. PCC 6803. Cyanophycin is a dynamic carbon/nitrogen storage polymer (multi-arginyl-l-polyaspartate) that is conditionally present in most cyanobacteria and a few heterotrophic bacteria as cellular inclusion granules. Here, we show that the cyanophycin-synthesizing enzyme CphA in the nonactive state localizes diffusely in the cytoplasm. When cyanophycin synthesis is triggered, active CphA first aggregates into foci and then covers the surface of mature cyanophycin granules, which in vitro requires Mg2+ as a cofactor. Cyanophycin accumulation enables Synechocystis sp. to optimize nitrogen assimilation under nitrogen-poor conditions, in particular when the nitrogen supply fluctuates and during day/night cycles, by allowing continuous nitrogen assimilation and storage. Therefore, cyanophycin provides the wild-type cyanobacterium with a clear fitness advantage over non-cyanophycin-producing cells in natural environments with fluctuating nitrogen supply.
Collapse
|
43
|
Spät P, Klotz A, Rexroth S, Maček B, Forchhammer K. Chlorosis as a Developmental Program in Cyanobacteria: The Proteomic Fundament for Survival and Awakening. Mol Cell Proteomics 2018; 17:1650-1669. [PMID: 29848780 DOI: 10.1074/mcp.ra118.000699] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/25/2018] [Indexed: 11/06/2022] Open
Abstract
Cyanobacteria that do not fix atmospheric nitrogen gas survive prolonged periods of nitrogen starvation in a chlorotic, dormant state where cell growth and metabolism are arrested. Upon nutrient availability, these dormant cells return to vegetative growth within 2-3 days. This resuscitation process is highly orchestrated and relies on the stepwise reinstallation and activation of essential cellular structures and functions. We have been investigating the transition to chlorosis and the return to vegetative growth as a simple model of a cellular developmental process and a fundamental survival strategy in biology. In the present study, we used quantitative proteomics and phosphoproteomics to describe the proteomic landscape of a dormant cyanobacterium and its dynamics during the transition to vegetative growth. We identified intriguing alterations in the set of ribosomal proteins, in RuBisCO components, in the abundance of central regulators and predicted metabolic enzymes. We found O-phosphorylation as an abundant protein modification in the chlorotic state, specifically of metabolic enzymes and proteins involved in photosynthesis. Nondegraded phycobiliproteins were hyperphosphorylated in the chlorotic state. We provide evidence that hyperphosphorylation of the terminal rod linker CpcD increases the lifespan of phycobiliproteins during chlorosis.
Collapse
Affiliation(s)
- Philipp Spät
- From the ‡Interfaculty Institute for Microbiology and Infection Medicine, Eberhard-Karls University Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.,¶Proteome Center Tuebingen, Eberhard-Karls-University Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Alexander Klotz
- From the ‡Interfaculty Institute for Microbiology and Infection Medicine, Eberhard-Karls University Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Sascha Rexroth
- §Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Boris Maček
- ¶Proteome Center Tuebingen, Eberhard-Karls-University Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Karl Forchhammer
- From the ‡Interfaculty Institute for Microbiology and Infection Medicine, Eberhard-Karls University Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany;
| |
Collapse
|