1
|
Walker RM, Zhang M, Burnap RL. Elucidating the role of primary and secondary sphere Zn 2+ ligands in the cyanobacterial CO 2 uptake complex NDH-1 4: The essentiality of arginine in zinc coordination and catalysis. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149149. [PMID: 38906312 DOI: 10.1016/j.bbabio.2024.149149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 06/09/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
Inorganic carbon uptake in cyanobacteria is facilitated by an energetically intensive CO2-concentrating mechanism (CCM). Specialized Type-1 NDH complexes function as a part of this mechanism to couple photosynthetic energy generated by redox reactions of the electron transport chain (ETC) to CO2 hydration. This active site of CO2 hydration incorporates an arginine side chain as a Zn ligand, diverging from the typical histidine and/or cysteine residues found in standard CAs. In this study, we focused on mutating three amino acids in the active site of the constitutively expressed NDH-14 CO2 hydration complex in Synechococcus sp. PCC7942: CupB-R91, which acts as a zinc ligand, and CupB-E95 and CupB-H89, both of which closely interact with the arginine ligand. These mutations aimed to explore how they affect the unusual metal ligation by CupB-R91 and potentially influence the unusual catalytic process. The most severe defects in activity among the targeted residues are due to a substitution of CupB-R91 and the ionically interacting E95 since both proved essential for the structural stability of the CupB protein. On the other hand, CupB-H89 mutations show a range of catalytic phenotypes indicating a role of this residue in the catalytic mechanism of CO2-hydration, but no evidence was obtained for aberrant carbonic anhydrase activity that would have indicated uncoupling of the CO2-hydration activity from proton pumping. The results are discussed in terms of possible alternative CO2 hydration mechanisms.
Collapse
Affiliation(s)
- Ross M Walker
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Minquan Zhang
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
| |
Collapse
|
2
|
Pulsford SB, Outram MA, Förster B, Rhodes T, Williams SJ, Badger MR, Price GD, Jackson CJ, Long BM. Cyanobacterial α-carboxysome carbonic anhydrase is allosterically regulated by the Rubisco substrate RuBP. SCIENCE ADVANCES 2024; 10:eadk7283. [PMID: 38728392 PMCID: PMC11086599 DOI: 10.1126/sciadv.adk7283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/08/2024] [Indexed: 05/12/2024]
Abstract
Cyanobacterial CO2 concentrating mechanisms (CCMs) sequester a globally consequential proportion of carbon into the biosphere. Proteinaceous microcompartments, called carboxysomes, play a critical role in CCM function, housing two enzymes to enhance CO2 fixation: carbonic anhydrase (CA) and Rubisco. Despite its importance, our current understanding of the carboxysomal CAs found in α-cyanobacteria, CsoSCA, remains limited, particularly regarding the regulation of its activity. Here, we present a structural and biochemical study of CsoSCA from the cyanobacterium Cyanobium sp. PCC7001. Our results show that the Cyanobium CsoSCA is allosterically activated by the Rubisco substrate ribulose-1,5-bisphosphate and forms a hexameric trimer of dimers. Comprehensive phylogenetic and mutational analyses are consistent with this regulation appearing exclusively in cyanobacterial α-carboxysome CAs. These findings clarify the biologically relevant oligomeric state of α-carboxysomal CAs and advance our understanding of the regulation of photosynthesis in this globally dominant lineage.
Collapse
Affiliation(s)
- Sacha B. Pulsford
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Megan A. Outram
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Britta Förster
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Timothy Rhodes
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Simon J. Williams
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Murray R. Badger
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - G. Dean Price
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Colin J. Jackson
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Benedict M. Long
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| |
Collapse
|
3
|
Kupriyanova EV, Pronina NA, Los DA. Adapting from Low to High: An Update to CO 2-Concentrating Mechanisms of Cyanobacteria and Microalgae. PLANTS (BASEL, SWITZERLAND) 2023; 12:1569. [PMID: 37050194 PMCID: PMC10096703 DOI: 10.3390/plants12071569] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 06/19/2023]
Abstract
The intracellular accumulation of inorganic carbon (Ci) by microalgae and cyanobacteria under ambient atmospheric CO2 levels was first documented in the 80s of the 20th Century. Hence, a third variety of the CO2-concentrating mechanism (CCM), acting in aquatic photoautotrophs with the C3 photosynthetic pathway, was revealed in addition to the then-known schemes of CCM, functioning in CAM and C4 higher plants. Despite the low affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) of microalgae and cyanobacteria for the CO2 substrate and low CO2/O2 specificity, CCM allows them to perform efficient CO2 fixation in the reductive pentose phosphate (RPP) cycle. CCM is based on the coordinated operation of strategically located carbonic anhydrases and CO2/HCO3- uptake systems. This cooperation enables the intracellular accumulation of HCO3-, which is then employed to generate a high concentration of CO2 molecules in the vicinity of Rubisco's active centers compensating up for the shortcomings of enzyme features. CCM functions as an add-on to the RPP cycle while also acting as an important regulatory link in the interaction of dark and light reactions of photosynthesis. This review summarizes recent advances in the study of CCM molecular and cellular organization in microalgae and cyanobacteria, as well as the fundamental principles of its functioning and regulation.
Collapse
|
4
|
Fuentes-Cabrera M, Sakkos JK, Ducat DC, Ziatdinov M. Investigating Carboxysome Morphology Dynamics with a Rotationally Invariant Variational Autoencoder. J Phys Chem A 2022; 126:5021-5030. [PMID: 35880991 DOI: 10.1021/acs.jpca.2c02179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carboxysomes are a class of bacterial microcompartments that form proteinaceous organelles within the cytoplasm of cyanobacteria and play a central role in photosynthetic metabolism by defining a cellular microenvironment permissive to CO2 fixation. Critical aspects of the assembly of the carboxysomes remain relatively unknown, especially with regard to the dynamics of this microcompartment. Progress in understanding carboxysome dynamics is impeded in part because analysis of the subtle changes in carboxysome morphology with microscopy remains a low-throughput and subjective process. Here we use deep learning techniques, specifically a Rotationally Invariant Variational Autoencoder (rVAE), to analyze fluorescence microscopy images of cyanobacteria bearing a carboxysome reporter and quantitatively evaluate how carboxysome shell remodelling impacts subtle trends in the morphology of the microcompartment over time. Toward this goal, we use a recently developed tool to control endogenous protein levels, including carboxysomal components, in the model cyanobacterium Synechococcous elongatus PCC 7942. By utilization of this system, proteins that compose the carboxysome can be tuned in real time as a method to examine carboxysome dynamics. We find that rVAEs are able to assist in the quantitative evaluation of changes in carboxysome numbers, shape, and size over time. We propose that rVAEs may be a useful tool to accelerate the analysis of carboxysome assembly and dynamics in response to genetic or environmental perturbation and may be more generally useful to probe regulatory processes involving a broader array of bacterial microcompartments.
Collapse
Affiliation(s)
- Miguel Fuentes-Cabrera
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jonathan K Sakkos
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
| | - Daniel C Ducat
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Maxim Ziatdinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| |
Collapse
|
5
|
Glyceroglycolipid Metabolism Regulations under Phosphate Starvation Revealed by Transcriptome Analysis in Synechococcus elongatus PCC 7942. Mar Drugs 2020; 18:md18070360. [PMID: 32668657 PMCID: PMC7401256 DOI: 10.3390/md18070360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/04/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022] Open
Abstract
Glyceroglycolipids, abundant in cyanobacteria's photosynthetic membranes, present bioactivities and pharmacological activities, and can be widely used in the pharmaceutical industry. Environmental factors could alter the contents and compositions of cyanobacteria glyceroglycolipids, but the regulation mechanism remains unclear. Therefore, the glyceroglycolipids contents and the transcriptome in Synechococcus elongatus PCC 7942 were analyzed under phosphate starvation. Under phosphate starvation, the decrease of monogalactosyl diacylglycerol (MGDG) and increases of digalactosyl diacylglycerol (DGDG) and sulfoquinovosyl diacylglycerol (SQDG) led to a decrease in the MGDG/DGDG ratio, from 4:1 to 5:3, after 12 days of cultivation. However, UDP-sulfoquinovose synthase gene sqdB, and the SQDG synthase gene sqdX, were down-regulated, and the decreased MGDG/DGDG ratio was later increased back to 2:1 after 15 days of cultivation, suggesting the regulation of glyceroglycolipids on day 12 was based on the MGDG/DGDG ratio maintaining glyceroglycolipid homeostasis. There are 12 differentially expressed transcriptional regulators that could be potential candidates related to glyceroglycolipid regulation, according to the transcriptome analysis. The transcriptome analysis also suggested post-transcriptional or post-translational regulations in glyceroglycolipid synthesis. This study provides further insights into glyceroglycolipid metabolism, as well as the scientific basis for glyceroglycolipid synthesis optimization and cyanobacteria glyceroglycolipids utilization via metabolic engineering.
Collapse
|
6
|
Géron A, Werner J, Wattiez R, Lebaron P, Matallana-Surget S. Deciphering the Functioning of Microbial Communities: Shedding Light on the Critical Steps in Metaproteomics. Front Microbiol 2019; 10:2395. [PMID: 31708885 PMCID: PMC6821674 DOI: 10.3389/fmicb.2019.02395] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/03/2019] [Indexed: 11/13/2022] Open
Abstract
Unraveling the complex structure and functioning of microbial communities is essential to accurately predict the impact of perturbations and/or environmental changes. From all molecular tools available today to resolve the dynamics of microbial communities, metaproteomics stands out, allowing the establishment of phenotype-genotype linkages. Despite its rapid development, this technology has faced many technical challenges that still hamper its potential power. How to maximize the number of protein identification, improve quality of protein annotation, and provide reliable ecological interpretation are questions of immediate urgency. In our study, we used a robust metaproteomic workflow combining two protein fractionation approaches (gel-based versus gel-free) and four protein search databases derived from the same metagenome to analyze the same seawater sample. The resulting eight metaproteomes provided different outcomes in terms of (i) total protein numbers, (ii) taxonomic structures, and (iii) protein functions. The characterization and/or representativeness of numerous proteins from ecologically relevant taxa such as Pelagibacterales, Rhodobacterales, and Synechococcales, as well as crucial environmental processes, such as nutrient uptake, nitrogen assimilation, light harvesting, and oxidative stress response, were found to be particularly affected by the methodology. Our results provide clear evidences that the use of different protein search databases significantly alters the biological conclusions in both gel-free and gel-based approaches. Our findings emphasize the importance of diversifying the experimental workflow for a comprehensive metaproteomic study.
Collapse
Affiliation(s)
- Augustin Géron
- Division of Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
- Department of Proteomic and Microbiology, University of Mons, Mons, Belgium
| | - Johannes Werner
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Ruddy Wattiez
- Department of Proteomic and Microbiology, University of Mons, Mons, Belgium
| | - Philippe Lebaron
- Sorbonne Universités, UPMC Université Paris 06, USR 3579, LBBM, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - Sabine Matallana-Surget
- Division of Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| |
Collapse
|
7
|
Sun Y, Wollman AJM, Huang F, Leake MC, Liu LN. Single-Organelle Quantification Reveals Stoichiometric and Structural Variability of Carboxysomes Dependent on the Environment. THE PLANT CELL 2019; 31:1648-1664. [PMID: 31048338 PMCID: PMC6635877 DOI: 10.1105/tpc.18.00787] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/02/2019] [Indexed: 05/25/2023]
Abstract
The carboxysome is a complex, proteinaceous organelle that plays essential roles in carbon assimilation in cyanobacteria and chemoautotrophs. It comprises hundreds of protein homologs that self-assemble in space to form an icosahedral structure. Despite its significance in enhancing CO2 fixation and potentials in bioengineering applications, the formation of carboxysomes and their structural composition, stoichiometry, and adaptation to cope with environmental changes remain unclear. Here we use live-cell single-molecule fluorescence microscopy, coupled with confocal and electron microscopy, to decipher the absolute protein stoichiometry and organizational variability of single β-carboxysomes in the model cyanobacterium Synechococcus elongatus PCC7942. We determine the physiological abundance of individual building blocks within the icosahedral carboxysome. We further find that the protein stoichiometry, diameter, localization, and mobility patterns of carboxysomes in cells depend sensitively on the microenvironmental levels of CO2 and light intensity during cell growth, revealing cellular strategies of dynamic regulation. These findings, also applicable to other bacterial microcompartments and macromolecular self-assembling systems, advance our knowledge of the principles that mediate carboxysome formation and structural modulation. It will empower rational design and construction of entire functional metabolic factories in heterologous organisms, for example crop plants, to boost photosynthesis and agricultural productivity.
Collapse
Affiliation(s)
- Yaqi Sun
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Adam J M Wollman
- Biological Physical Sciences Institute, Departments of Physics and Biology, University of York, YO10 5DD, United Kingdom
| | - Fang Huang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Mark C Leake
- Biological Physical Sciences Institute, Departments of Physics and Biology, University of York, YO10 5DD, United Kingdom
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| |
Collapse
|
8
|
Kupriyanova EV, Sinetova MA, Mironov KS, Novikova GV, Dykman LA, Rodionova MV, Gabrielyan DA, Los DA. Highly active extracellular α-class carbonic anhydrase of Cyanothece sp. ATCC 51142. Biochimie 2019; 160:200-209. [DOI: 10.1016/j.biochi.2019.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/15/2019] [Indexed: 12/31/2022]
|
9
|
Stable Reference Gene Selection for RT-qPCR Analysis in Synechococcus elongatus PCC 7942 under Abiotic Stresses. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7630601. [PMID: 31139651 PMCID: PMC6500708 DOI: 10.1155/2019/7630601] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/15/2019] [Accepted: 04/07/2019] [Indexed: 12/27/2022]
Abstract
Synechococcus elongatus PCC 7942 (S. elongatus PCC 7942) is a model cyanobacteria species for circadian clock mechanism studies. It has also been widely used as a bioreactor to produce biofuels and other metabolic products. Quantitative real-time PCR (qPCR) technology is the most commonly used method for studying the expression of specific genes, in which the relative expression level of target genes is calibrated by stably expressed internal reference genes. In this work, we examined the expression of nine candidate reference genes in time-course samples of S. elongatus PCC 7942 under no treatment (control), NaCl-stress conditions, H2O2-stress conditions, and high light-stress conditions. Based on the qPCR amplification parameters, the stability ranking of these candidate reference genes was established by three statistical software programs, geNorm, NormFinder, and BestKeeper. Considering all the stress conditions or high light stress alone, the results showed that the combination of prs and secA was the best choice for the double reference gene calibration method by qPCR. The combination of secA and ppc, rimM and rnpA, rnpA, and ilvD was most stable under no treatment, NaCl-stress conditions, and H2O2-stress conditions, respectively. rimM was stable under only special conditions and should be carefully chosen. 16S and rnpB were not suitable as internal reference genes for S. elongatus PCC 7942 qPCR experiments under all experimental conditions. To validate the above results, a cyanobacterial core clock gene, kaiC, was used to evaluate the actual performance of the optimized reference genes by qPCR, as well as the worst reference genes under different stress conditions. The results indicated that the best reference gene yielded more accurate calibration results for qPCR experiments carried out in S. elongatus PCC 7942 time-course samples.
Collapse
|
10
|
Hwangbo K, Lim JM, Jeong SW, Vikramathithan J, Park YI, Jeong WJ. Elevated Inorganic Carbon Concentrating Mechanism Confers Tolerance to High Light in an Arctic Chlorella sp. ArM0029B. FRONTIERS IN PLANT SCIENCE 2018; 9:590. [PMID: 29868055 PMCID: PMC5949578 DOI: 10.3389/fpls.2018.00590] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/16/2018] [Indexed: 05/29/2023]
Abstract
Microalgae and higher plants employ an inorganic carbon (Ci) concentrating mechanism (CCM) to increase CO2 availability to Rubisco. Operation of the CCM should enhance the activity of the Calvin cycle, which could act as an electron sink for electrons generated by photosynthesis, and lower the redox status of photosynthetic electron transport chains. In this study, a hypothesis that microalgal cells with fully operating CCM are less likely to be photodamaged was tested by comparing a Chlorella mutant with its wild type (WT). The mutant acquired by screening gamma-ray-induced mutant libraries of Chlorella sp. ArM0029B exhibited constitutively active CCM (CAC) even in the presence of additional Ci sources under mixotrophic growth conditions. In comparison to the WT alga, the mutant named to constitutively active CCM1 (CAC1) showed more transcript levels for genes coding proteins related to CCM such as Ci transporters and carbonic anhydrases (CA), and greater levels of intracellular Ci content and CA activity regardless of whether growth is limited by light or not. Under photoinhibitory conditions, CAC1 mutant showed faster growth than WT cells with more PSII reaction center core component D1 protein (encoded by psbA), higher photochemical efficiency as estimated by the chlorophyll fluorescence parameter (Fv/Fm), and fewer reactive oxygen species (ROS). Interestingly, high light (HL)-induced increase in ROS contents in WT cells was significantly inhibited by bicarbonate supplementation. It is concluded that constitutive operation of CCM endows Chlorella cells with resistance to HL partly by reducing the endogenous generation of ROS. These results will provide useful information on the interaction between CCM expression, ROS production, and photodamage in Chlorella and related microalgae.
Collapse
Affiliation(s)
- Kwon Hwangbo
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biological Sciences, Chungnam National University, Daejeon, South Korea
| | - Jong-Min Lim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Seok-Won Jeong
- Department of Biological Sciences, Chungnam National University, Daejeon, South Korea
| | - Jayaraman Vikramathithan
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Youn-Il Park
- Department of Biological Sciences, Chungnam National University, Daejeon, South Korea
| | - Won-Joong Jeong
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| |
Collapse
|
11
|
Kupriyanova EV, Cho SM, Park YI, Pronina NA, Los DA. The complete genome of a cyanobacterium from a soda lake reveals the presence of the components of CO 2-concentrating mechanism. PHOTOSYNTHESIS RESEARCH 2016; 130:151-165. [PMID: 26908147 DOI: 10.1007/s11120-016-0235-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 02/12/2016] [Indexed: 06/05/2023]
Abstract
At present geological epoch, the carbon concentrating mechanism (CCM) of cyanobacteria represents the obligatory tool for adaptation to low content of CO2 in the atmosphere and for the maintenance of sufficient photosynthetic activity. Functional CCM was found in modern cyanobacteria from different ecological niches. However, the presence of such mechanism in species that inhabit soda lakes is not obvious due to high content of inorganic carbon (C i) in the environment. Here we analyze CCM components that have been identified by sequencing of the whole genome of the alkaliphilic cyanobacterium Microcoleus sp. IPPAS B-353. The composition of the CCM components of Microcoleus is similar to that of 'model' β-cyanobacteria, freshwater and marine Synechococcus or Synechocystis spp. However, CahB1 protein of Microcoleus, which is the homolog of CcaA, the carboxysomal β-type carbonic anhydrase (CA) of β-cyanobacteria, appeared to be the only active CA located in cell envelopes. The conservative regions of CcmM, CahG (a homolog of archeal γ-CAs, Cam/CamH), and ChpX of Microcoleus possess single amino acid substitutions that may cause a lack of CA activities. Unlike model cyanobacteria, Microcoleus induces only one BicA-type bicarbonate transporter in response to C i limitation. The differences in the appearance of CCM components and in their characteristics between alkaliphilic Microcoleus and freshwater or marine cyanobacteria are described. The possible reasons for the maintenance of CCM components in cyanobacteria, which permanently live at high concentrations of C i in soda lakes, are discussed.
Collapse
Affiliation(s)
- Elena V Kupriyanova
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya street 35, Moscow, Russia, 127276.
| | - Sung Mi Cho
- Department of Biological Sciences, Chungnam National University, Daejeon, 305-764, Korea
| | - Youn-Il Park
- Department of Biological Sciences, Chungnam National University, Daejeon, 305-764, Korea
| | - Natalia A Pronina
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya street 35, Moscow, Russia, 127276
| | - Dmitry A Los
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya street 35, Moscow, Russia, 127276
| |
Collapse
|
12
|
Orf I, Schwarz D, Kaplan A, Kopka J, Hess WR, Hagemann M, Klähn S. CyAbrB2 Contributes to the Transcriptional Regulation of Low CO2 Acclimation in Synechocystis sp. PCC 6803. PLANT & CELL PHYSIOLOGY 2016; 57:2232-2243. [PMID: 27638927 DOI: 10.1093/pcp/pcw146] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/29/2016] [Indexed: 06/06/2023]
Abstract
Acclimation to low CO2 conditions in cyanobacteria involves the co-ordinated regulation of genes mainly encoding components of the carbon-concentrating mechanism (CCM). Making use of several independent microarray data sets, a core set of CO2-regulated genes was defined for the model strain Synechocystis sp. PCC 6803. On the transcriptional level, the CCM is mainly regulated by the well-characterized transcriptional regulators NdhR (= CcmR) and CmpR. However, the role of an additional regulatory protein, namely cyAbrB2 belonging to the widely distributed AbrB regulator family that was originally characterized in the genus Bacillus, is less defined. Here we present results of transcriptomic and metabolic profiling of the wild type and a ΔcyabrB2 mutant of Synechocystis sp. PCC 6803 after shifts from high CO2 (5% in air, HC) to low CO2 (0.04%, LC). Evaluation of the transcriptomic data revealed that cyAbrB2 is involved in the regulation of several CCM-related genes such as sbtA/B, ndhF3/ndhD3/cupA and cmpABCD under LC conditions, but apparently acts supplementary to NdhR and CmpR. Under HC conditions, cyAbrB2 deletion affects the transcript abundance of PSII subunits, light-harvesting components and Calvin-Benson-Bassham cycle enzymes. These changes are also reflected by down-regulation of primary metabolite pools. The data suggest a role for cyAbrB2 in adjusting primary carbon and nitrogen metabolism to photosynthetic activity under fluctuating environmental conditions. The findings were integrated into the current knowledge about the acquisition of inorganic carbon (Ci), the CCM and parts of its regulation on the transcriptional level.
Collapse
Affiliation(s)
- Isabel Orf
- Max-Planck-Institute of Molecular Plant Physiology, Department of Molecular Physiology: Applied Metabolome Analysis, Potsdam-Golm, Germany
| | - Doreen Schwarz
- Plant Physiology Department, Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Joachim Kopka
- Max-Planck-Institute of Molecular Plant Physiology, Department of Molecular Physiology: Applied Metabolome Analysis, Potsdam-Golm, Germany
| | - Wolfgang R Hess
- Genetics & Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | - Stephan Klähn
- Genetics & Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| |
Collapse
|
13
|
Sun Y, Casella S, Fang Y, Huang F, Faulkner M, Barrett S, Liu LN. Light Modulates the Biosynthesis and Organization of Cyanobacterial Carbon Fixation Machinery through Photosynthetic Electron Flow. PLANT PHYSIOLOGY 2016; 171:530-41. [PMID: 26956667 PMCID: PMC4854705 DOI: 10.1104/pp.16.00107] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/06/2016] [Indexed: 05/08/2023]
Abstract
Cyanobacteria have evolved effective adaptive mechanisms to improve photosynthesis and CO2 fixation. The central CO2-fixing machinery is the carboxysome, which is composed of an icosahedral proteinaceous shell encapsulating the key carbon fixation enzyme, Rubisco, in the interior. Controlled biosynthesis and ordered organization of carboxysomes are vital to the CO2-fixing activity of cyanobacterial cells. However, little is known about how carboxysome biosynthesis and spatial positioning are physiologically regulated to adjust to dynamic changes in the environment. Here, we used fluorescence tagging and live-cell confocal fluorescence imaging to explore the biosynthesis and subcellular localization of β-carboxysomes within a model cyanobacterium, Synechococcus elongatus PCC7942, in response to light variation. We demonstrated that β-carboxysome biosynthesis is accelerated in response to increasing light intensity, thereby enhancing the carbon fixation activity of the cell. Inhibition of photosynthetic electron flow impairs the accumulation of carboxysomes, indicating a close coordination between β-carboxysome biogenesis and photosynthetic electron transport. Likewise, the spatial organization of carboxysomes in the cell correlates with the redox state of photosynthetic electron transport chain. This study provides essential knowledge for us to modulate the β-carboxysome biosynthesis and function in cyanobacteria. In translational terms, the knowledge is instrumental for design and synthetic engineering of functional carboxysomes into higher plants to improve photosynthesis performance and CO2 fixation.
Collapse
Affiliation(s)
- Yaqi Sun
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Selene Casella
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Yi Fang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Fang Huang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Matthew Faulkner
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Steve Barrett
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| |
Collapse
|
14
|
Sandrini G, Tann RP, Schuurmans JM, van Beusekom SAM, Matthijs HCP, Huisman J. Diel Variation in Gene Expression of the CO2-Concentrating Mechanism during a Harmful Cyanobacterial Bloom. Front Microbiol 2016; 7:551. [PMID: 27148233 PMCID: PMC4840274 DOI: 10.3389/fmicb.2016.00551] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/04/2016] [Indexed: 12/13/2022] Open
Abstract
Dense phytoplankton blooms in eutrophic waters often experience large daily fluctuations in environmental conditions. We investigated how this diel variation affects in situ gene expression of the CO2-concentrating mechanism (CCM) and other selected genes of the harmful cyanobacterium Microcystis aeruginosa. Photosynthetic activity of the cyanobacterial bloom depleted the dissolved CO2 concentration, raised pH to 10, and caused large diel fluctuations in the bicarbonate and O2 concentration. The Microcystis population consisted of three Ci uptake genotypes that differed in the presence of the low-affinity and high-affinity bicarbonate uptake genes bicA and sbtA. Expression of the bicarbonate uptake genes bicA, sbtA, and cmpA (encoding a subunit of the high-affinity bicarbonate uptake system BCT1), the CCM transcriptional regulator gene ccmR and the photoprotection gene flv4 increased at first daylight and was negatively correlated with the bicarbonate concentration. In contrast, genes of the two CO2 uptake systems were constitutively expressed, whereas expression of the RuBisCO chaperone gene rbcX, the carboxysome gene ccmM, and the photoprotection gene isiA was highest at night and down-regulated during daytime. In total, our results show that the harmful cyanobacterium Microcystis is very responsive to the large diel variations in carbon and light availability often encountered in dense cyanobacterial blooms.
Collapse
Affiliation(s)
- Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Robert P. Tann
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - J. Merijn Schuurmans
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
- Department of Aquatic Ecology, Netherlands Institute of EcologyWageningen, Netherlands
| | - Sebastiaan A. M. van Beusekom
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Hans C. P. Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| |
Collapse
|
15
|
Benson PJ, Purcell-Meyerink D, Hocart CH, Truong TT, James GO, Rourke L, Djordjevic MA, Blackburn SI, Price GD. Factors Altering Pyruvate Excretion in a Glycogen Storage Mutant of the Cyanobacterium, Synechococcus PCC7942. Front Microbiol 2016; 7:475. [PMID: 27092129 PMCID: PMC4820439 DOI: 10.3389/fmicb.2016.00475] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/22/2016] [Indexed: 12/20/2022] Open
Abstract
Interest in the production of carbon commodities from photosynthetically fixed CO2 has focused attention on cyanobacteria as a target for metabolic engineering and pathway investigation. We investigated the redirection of carbon flux in the model cyanobacterial species, Synechococcus elongatus PCC 7942, under nitrogen deprivation, for optimized production of the industrially desirable compound, pyruvate. Under nitrogen limited conditions, excess carbon is naturally stored as the multi-branched polysaccharide, glycogen, but a block in glycogen synthesis, via knockout mutation in the gene encoding ADP-glucose pyrophosphorylase (glgC), results in the accumulation of the organic acids, pyruvate and 2-oxoglutarate, as overflow excretions into the extracellular media. The ΔglgC strain, under 48 h of N-deprivation was shown to excrete pyruvate for the first time in this strain. Additionally, by increasing culture pH, to pH 10, it was possible to substantially elevate excretion of pyruvate, suggesting the involvement of an unknown substrate/proton symporter for export. The ΔglgC mutant was also engineered to express foreign transporters for glucose and sucrose, and then grown photomixotrophically with exogenous organic carbon supply, as added 5 mM glucose or sucrose during N- deprivation. Under these conditions we observed a fourfold increase in extracellular pyruvate excretion when glucose was added, and a smaller increase with added sucrose. Although the magnitude of pyruvate excretion did not correlate with the capacity of the ΔglgC strain for bicarbonate-dependent photosynthetic O2 evolution, or with light intensity, there was, however, a positive correlation observed between the density of the starter culture prior to N-deprivation and the final extracellular pyruvate concentration. The factors that contribute to enhancement of pyruvate excretion are discussed, as well as consideration of whether the source of carbon for pyruvate excretion might be derived from photosynthetic CO2 fixation or from remobilisation of existing carbon stores.
Collapse
Affiliation(s)
- Phoebe J Benson
- Research School of Biology, Plant Sciences, Australian National University, Canberra ACT, Australia
| | - Diane Purcell-Meyerink
- Research School of Biology, Plant Sciences, Australian National University, CanberraACT, Australia; North Australia Marine Research Alliance, Arafura Timor Research Facility, DarwinNT, Australia
| | - Charles H Hocart
- Research School of Biology, Plant Sciences, Australian National University, Canberra ACT, Australia
| | - Thy T Truong
- Research School of Biology, Plant Sciences, Australian National University, Canberra ACT, Australia
| | - Gabriel O James
- Research School of Biology, Plant Sciences, Australian National University, CanberraACT, Australia; Heliase Genomics, University of AucklandAuckland, New Zealand
| | - Loraine Rourke
- Research School of Biology, Plant Sciences, Australian National University, Canberra ACT, Australia
| | - Michael A Djordjevic
- Research School of Biology, Plant Sciences, Australian National University, Canberra ACT, Australia
| | - Susan I Blackburn
- CSIRO National Research Collections Australia, Hobart TAS, Australia
| | - G D Price
- Research School of Biology, Plant Sciences, Australian National University, Canberra ACT, Australia
| |
Collapse
|
16
|
Tanaka A, Ohno N, Nakajima K, Matsuda Y. Light and CO2/cAMP Signal Cross Talk on the Promoter Elements of Chloroplastic β-Carbonic Anhydrase Genes in the Marine Diatom Phaeodactylum tricornutum. PLANT PHYSIOLOGY 2016; 170:1105-16. [PMID: 26662605 PMCID: PMC4734587 DOI: 10.1104/pp.15.01738] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/07/2015] [Indexed: 05/23/2023]
Abstract
Our previous study showed that three CO2/cAMP-responsive elements (CCRE) CCRE1, CCRE2, and CCRE3 in the promoter of the chloroplastic β-carbonic anhydrase 1 gene in the marine diatom Phaeodactylum tricornutum (Pptca1) were critical for the cAMP-mediated transcriptional response to ambient CO2 concentration. Pptca1 was activated under CO2 limitation, but the absence of light partially disabled this low-CO2-triggered transcriptional activation. This suppression effect disappeared when CCRE2 or two of three CCREs were replaced with a NotI restriction site, strongly suggesting that light signal cross-talks with CO2 on the cAMP-signal transduction pathway that targets CCREs. The paralogous chloroplastic carbonic anhydrase gene, ptca2 was also CO2/cAMP-responsive. The upstream truncation assay of the ptca2 promoter (Pptca2) revealed a short sequence of -367 to -333 relative to the transcription-start site to be a critical regulatory region for the CO2 and light responses. This core-regulatory region comprises one CCRE1 and two CCRE2 sequences. Further detailed analysis of Pptca2 clearly indicates that two CCRE2s are the cis-element governing the CO2/light response of Pptca2. The transcriptional activation of two Pptcas in CO2 limitation was evident under illumination with a photosynthetically active light wavelength, and an artificial electron acceptor from the reduction side of PSI efficiently inhibited Pptcas activation, while neither inhibition of the linear electron transport from PSII to PSI nor inhibition of ATP synthesis showed an effect on the promoter activity, strongly suggesting a specific involvement of the redox level of the stromal side of the PSI in the CO2/light cross talk.
Collapse
Affiliation(s)
- Atsushi Tanaka
- Research Center for the Development of Intelligent Self-Organized Biomaterials, Research Center for Environmental Bioscience, and Department of Bioscience, Kwansei-Gakuin University, 2-1 Gakuen, Sanda, Hyogo, Japan, 669-1337
| | - Naoki Ohno
- Research Center for the Development of Intelligent Self-Organized Biomaterials, Research Center for Environmental Bioscience, and Department of Bioscience, Kwansei-Gakuin University, 2-1 Gakuen, Sanda, Hyogo, Japan, 669-1337
| | - Kensuke Nakajima
- Research Center for the Development of Intelligent Self-Organized Biomaterials, Research Center for Environmental Bioscience, and Department of Bioscience, Kwansei-Gakuin University, 2-1 Gakuen, Sanda, Hyogo, Japan, 669-1337
| | - Yusuke Matsuda
- Research Center for the Development of Intelligent Self-Organized Biomaterials, Research Center for Environmental Bioscience, and Department of Bioscience, Kwansei-Gakuin University, 2-1 Gakuen, Sanda, Hyogo, Japan, 669-1337
| |
Collapse
|
17
|
Zhu LW, Zhang L, Wei LN, Li HM, Yuan ZP, Chen T, Tang YL, Liang XH, Tang YJ. Collaborative regulation of CO2 transport and fixation during succinate production in Escherichia coli. Sci Rep 2015; 5:17321. [PMID: 26626308 PMCID: PMC4667291 DOI: 10.1038/srep17321] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/19/2015] [Indexed: 02/05/2023] Open
Abstract
In Escherichia coli, succinic acid is synthesized by CO2 fixation-based carboxylation of C3 metabolites. A two-step process is involved in CO2 integration: CO2 uptake into the cell and CO2 fixation by carboxylation enzymes. The phosphoenolpyruvate (PEP) carboxylase (PPC) and carboxykinase (PCK) are two important carboxylation enzymes within the succinate synthetic pathway, while SbtA and BicA are two important bicarbonate transporters. In this study, we employed a dual expression system, in which genes regulating both CO2 uptake and fixation were co-overexpressed, or overexpressed individually to improve succinate biosynthesis. Active CO2 uptake was observed by the expression of SbtA or/and BicA, but the succinate biosynthesis was decreased. The succinate production was significantly increased only when a CO2 fixation gene (ppc or pck) and a CO2 transport gene (sbtA or bicA) were co-expressed. Co-expression of pck and sbtA provided the best succinate production among all the strains. The highest succinate production of 73.4 g L−1 was 13.3%, 66.4% or 15.0% higher than that obtained with the expression of PCK, SbtA alone, or with empty plasmids, respectively. We believe that combined regulation of CO2 transport and fixation is critical for succinate production. Imbalanced gene expression may disturb the cellular metabolism and succinate production.
Collapse
Affiliation(s)
- Li-Wen Zhu
- Key Laboratory of Fermentation Engineering (Ministry of Education) and Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068 China
| | - Lei Zhang
- Key Laboratory of Fermentation Engineering (Ministry of Education) and Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068 China
| | - Li-Na Wei
- Key Laboratory of Fermentation Engineering (Ministry of Education) and Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068 China
| | - Hong-Mei Li
- Key Laboratory of Fermentation Engineering (Ministry of Education) and Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068 China
| | - Zhan-Peng Yuan
- Key Laboratory of Fermentation Engineering (Ministry of Education) and Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068 China
| | - Tao Chen
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 China
| | - Ya-Ling Tang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 China
| | - Xin-Hua Liang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 China
| | - Ya-Jie Tang
- Key Laboratory of Fermentation Engineering (Ministry of Education) and Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068 China
| |
Collapse
|
18
|
Sandrini G, Jakupovic D, Matthijs HCP, Huisman J. Strains of the Harmful Cyanobacterium Microcystis aeruginosa Differ in Gene Expression and Activity of Inorganic Carbon Uptake Systems at Elevated CO2 Levels. Appl Environ Microbiol 2015; 81:7730-9. [PMID: 26319871 PMCID: PMC4616958 DOI: 10.1128/aem.02295-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/22/2015] [Indexed: 11/20/2022] Open
Abstract
Cyanobacteria are generally assumed to be effective competitors at low CO2 levels because of their efficient CO2-concentrating mechanism (CCM), and yet how bloom-forming cyanobacteria respond to rising CO2 concentrations is less clear. Here, we investigate changes in CCM gene expression at ambient CO2 (400 ppm) and elevated CO2 (1,100 ppm) in six strains of the harmful cyanobacterium Microcystis. All strains downregulated cmpA encoding the high-affinity bicarbonate uptake system BCT1, whereas both the low- and high-affinity CO2 uptake genes were expressed constitutively. Four strains downregulated the bicarbonate uptake genes bicA and/or sbtA, whereas two strains showed constitutive expression of the bicA-sbtA operon. In one of the latter strains, a transposon insert in bicA caused low bicA and sbtA transcript levels, which made this strain solely dependent on BCT1 for bicarbonate uptake. Activity measurements of the inorganic carbon (Ci) uptake systems confirmed the CCM gene expression results. Interestingly, genes encoding the RuBisCO enzyme, structural carboxysome components, and carbonic anhydrases were not regulated. Hence, Microcystis mainly regulates the initial uptake of inorganic carbon, which might be an effective strategy for a species experiencing strongly fluctuating Ci concentrations. Our results show that CCM gene regulation of Microcystis varies among strains. The observed genetic and phenotypic variation in CCM responses may offer an important template for natural selection, leading to major changes in the genetic composition of harmful cyanobacterial blooms at elevated CO2.
Collapse
Affiliation(s)
- Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Dennis Jakupovic
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans C P Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
19
|
Wu Y, Beardall J, Gao K. Physiological Responses of a Model Marine Diatom to Fast pH Changes: Special Implications of Coastal Water Acidification. PLoS One 2015; 10:e0141163. [PMID: 26496125 PMCID: PMC4619668 DOI: 10.1371/journal.pone.0141163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/04/2015] [Indexed: 11/19/2022] Open
Abstract
Diatoms and other phytoplankton in coastal waters experience rapid pH changes in milieu due to high biological activities and/or upwelled CO2-rich waters. While CO2 concentrating mechanisms (CCMs) are employed by all diatoms tested to counter low CO2 availability in seawater, little is known how this mechanism responds to fast pH changes. In the present study, the model diatom Thalassiosira pseudonana was acclimated for 20 generations to low pH (7.81) at an elevated CO2 of 1000 μatm (HC) or to high pH (8.18) at ambient CO2 levels of 390 μatm (LC), then its physiological characteristics were investigated as cells were shifted from HC to LC or vice versa. The maximal electron transport rate (ETRmax) in the HC-acclimated cells was immediately reduced by decreased CO2 availability, showing much lower values compared to that of the LC-acclimated cells. However, the cells showed a high capacity to regain their photochemical performance regardless of the growth CO2 levels, with their ETRmax values recovering to initial levels in about 100 min. This result indicates that this diatom might modulate its CCMs quickly to maintain a steady state supply of CO2, which is required for sustaining photosynthesis. In addition, active uptake of CO2 could play a fundamental role during the induction of CCMs under CO2 limitation, since the cells maintained high ETR even when both intracellular and periplasmic carbonic anhydrases were inhibited. It is concluded that efficient regulation of the CCM is one of the key strategies for diatoms to survive in fast changing pH environment, e.g. for the tested species, which is a dominant species in coastal waters where highly fluctuating pH is observed.
Collapse
Affiliation(s)
- Yaping Wu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| |
Collapse
|
20
|
|
21
|
Abstract
Biological carbon dioxide fixation is an essential and crucial process catalyzed by both prokaryotic and eukaryotic organisms to allow ubiquitous atmospheric CO2 to be reduced to usable forms of organic carbon. This process, especially the Calvin-Bassham-Benson (CBB) pathway of CO2 fixation, provides the bulk of organic carbon found on earth. The enzyme ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RubisCO) performs the key and rate-limiting step whereby CO2 is reduced and incorporated into a precursor organic metabolite. This is a highly regulated process in diverse organisms, with the expression of genes that comprise the CBB pathway (the cbb genes), including RubisCO, specifically controlled by the master transcriptional regulator protein CbbR. Many organisms have two or more cbb operons that either are regulated by a single CbbR or employ a specific CbbR for each cbb operon. CbbR family members are versatile and accommodate and bind many different effector metabolites that influence CbbR's ability to control cbb transcription. Moreover, two members of the CbbR family are further posttranslationally modified via interactions with other transcriptional regulator proteins from two-component regulatory systems, thus augmenting CbbR-dependent control and optimizing expression of specific cbb operons. In addition to interactions with small effector metabolites and other regulator proteins, CbbR proteins may be selected that are constitutively active and, in some instances, elevate the level of cbb expression relative to wild-type CbbR. Optimizing CbbR-dependent control is an important consideration for potentially using microbes to convert CO2 to useful bioproducts.
Collapse
|
22
|
Sandrini G, Cunsolo S, Schuurmans JM, Matthijs HCP, Huisman J. Changes in gene expression, cell physiology and toxicity of the harmful cyanobacterium Microcystis aeruginosa at elevated CO2. Front Microbiol 2015; 6:401. [PMID: 25999931 PMCID: PMC4419860 DOI: 10.3389/fmicb.2015.00401] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/17/2015] [Indexed: 12/31/2022] Open
Abstract
Rising CO2 concentrations may have large effects on aquatic microorganisms. In this study, we investigated how elevated pCO2 affects the harmful freshwater cyanobacterium Microcystis aeruginosa. This species is capable of producing dense blooms and hepatotoxins called microcystins. Strain PCC 7806 was cultured in chemostats that were shifted from low to high pCO2 conditions. This resulted in a transition from a C-limited to a light-limited steady state, with a ~2.7-fold increase of the cyanobacterial biomass and ~2.5-fold more microcystin per cell. Cells increased their chlorophyll a and phycocyanin content, and raised their PSI/PSII ratio at high pCO2. Surprisingly, cells had a lower dry weight and contained less carbohydrates, which might be an adaptation to improve the buoyancy of Microcystis when light becomes more limiting at high pCO2. Only 234 of the 4691 genes responded to elevated pCO2. For instance, expression of the carboxysome, RuBisCO, photosystem and C metabolism genes did not change significantly, and only a few N assimilation genes were expressed differently. The lack of large-scale changes in the transcriptome could suit a buoyant species that lives in eutrophic lakes with strong CO2 fluctuations very well. However, we found major responses in inorganic carbon uptake. At low pCO2, cells were mainly dependent on bicarbonate uptake, whereas at high pCO2 gene expression of the bicarbonate uptake systems was down-regulated and cells shifted to CO2 and low-affinity bicarbonate uptake. These results show that the need for high-affinity bicarbonate uptake systems ceases at elevated CO2. Moreover, the combination of an increased cyanobacterial abundance, improved buoyancy, and higher toxin content per cell indicates that rising atmospheric CO2 levels may increase the problems associated with the harmful cyanobacterium Microcystis in eutrophic lakes.
Collapse
Affiliation(s)
- Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Serena Cunsolo
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - J. Merijn Schuurmans
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
- Department of Aquatic Ecology, Netherlands Institute of EcologyWageningen, Netherlands
| | - Hans C. P. Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands
| |
Collapse
|
23
|
Burnap RL, Hagemann M, Kaplan A. Regulation of CO2 Concentrating Mechanism in Cyanobacteria. Life (Basel) 2015; 5:348-71. [PMID: 25636131 PMCID: PMC4390856 DOI: 10.3390/life5010348] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/15/2015] [Accepted: 01/21/2015] [Indexed: 12/31/2022] Open
Abstract
In this chapter, we mainly focus on the acclimation of cyanobacteria to the changing ambient CO2 and discuss mechanisms of inorganic carbon (Ci) uptake, photorespiration, and the regulation among the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. The structural components for several of the transport and uptake mechanisms are described and the progress towards elucidating their regulation is discussed in the context of studies, which have documented metabolomic changes in response to changes in Ci availability. Genes for several of the transport and uptake mechanisms are regulated by transcriptional regulators that are in the LysR-transcriptional regulator family and are known to act in concert with small molecule effectors, which appear to be well-known metabolites. Signals that trigger changes in gene expression and enzyme activity correspond to specific "regulatory metabolites" whose concentrations depend on the ambient Ci availability. Finally, emerging evidence for an additional layer of regulatory complexity involving small non-coding RNAs is discussed.
Collapse
Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Martin Hagemann
- Institute Biosciences, Department Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, Rostock D-18059, Germany.
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| |
Collapse
|
24
|
Holland SC, Kappell AD, Burnap RL. Redox changes accompanying inorganic carbon limitation in Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:355-363. [PMID: 25490207 DOI: 10.1016/j.bbabio.2014.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 11/26/2014] [Accepted: 12/02/2014] [Indexed: 12/27/2022]
Abstract
Inorganic carbon (Ci) is the major sink for photosynthetic reductant in organisms capable of oxygenic photosynthesis. In the absence of abundant Ci, the cyanobacterium Synechocystis sp. strain PCC6803 expresses a high affinity Ci acquisition system, the CO2-concentrating mechanisms (CCM), controlled by the transcriptional regulator CcmR and the metabolites NADP+ and α-ketoglutarate, which act as co-repressors of CcmR by modulating its DNA binding. The CCM thus responds to internal cellular redox changes during the transition from Ci-replete to Ci-limited conditions. However, the actual changes in the metabolic state of the NADPH/NADP+ system that occur during the transition to Ci-limited conditions remain ill-defined. Analysis of changes in the redox state of cells experiencing Ci limitation reveals systematic changes associated with physiological adjustments and a trend towards the quinone and NADP pools becoming highly reduced. A rapid and persistent increase in F0 was observed in cells reaching the Ci-limited state, as was the induction of photoprotective fluorescence quenching. Systematic changes in the fluorescence induction transients were also observed. As with Chl fluorescence, a transient reduction of the NADPH pool ('M' peak), is assigned to State 2→State 1 transition associated with increased electron flow to NADP+. This was followed by a characteristic decline, which was abolished by Ci limitation or inhibition of the Calvin-Benson-Bassham (CBB) cycle and is thus assigned to the activation of the CBB cycle. The results are consistent with the proposed regulation of the CCM and provide new information on the nature of the Chl and NADPH fluorescence induction curves.
Collapse
Affiliation(s)
- Steven C Holland
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Anthony D Kappell
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
| |
Collapse
|
25
|
Isensee K, Erez J, Stoll HM. Detection of a variable intracellular acid-labile carbon pool in Thalassiosira weissflogii (Heterokontophyta) and Emiliania huxleyi (Haptophyta) in response to changes in the seawater carbon system. PHYSIOLOGIA PLANTARUM 2014; 150:321-338. [PMID: 23992373 DOI: 10.1111/ppl.12096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/30/2013] [Accepted: 08/14/2013] [Indexed: 06/02/2023]
Abstract
Accumulation of an intracellular pool of carbon (C(i) pool) is one strategy by which marine algae overcome the low abundance of dissolved CO2 (CO2 (aq) ) in modern seawater. To identify the environmental conditions under which algae accumulate an acid-labile C(i) pool, we applied a (14) C pulse-chase method, used originally in dinoflagellates, to two new classes of algae, coccolithophorids and diatoms. This method measures the carbon accumulation inside the cells without altering the medium carbon chemistry or culture cell density. We found that the diatom Thalassiosira weissflogii [(Grunow) G. Fryxell & Hasle] and a calcifying strain of the coccolithophorid Emiliania huxleyi [(Lohmann) W. W. Hay & H. P. Mohler] develop significant acid-labile C(i) pools. C(i) pools are measureable in cells cultured in media with 2-30 µmol l(-1) CO2 (aq), corresponding to a medium pH of 8.6-7.9. The absolute C(i) pool was greater for the larger celled diatoms. For both algal classes, the C(i) pool became a negligible contributor to photosynthesis once CO2 (aq) exceeded 30 µmol l(-1) . Combining the (14) C pulse-chase method and (14) C disequilibrium method enabled us to assess whether E. huxleyi and T. weissflogii exhibited thresholds for foregoing accumulation of DIC or reduced the reliance on bicarbonate uptake with increasing CO2 (aq) . We showed that the C(i) pool decreases with higher CO2 :HCO3 (-) uptake rates.
Collapse
Affiliation(s)
- Kirsten Isensee
- Departmento de Geologia, Universidad Oviedo, 33006 Oviedo, Asturias, Spain
| | | | | |
Collapse
|
26
|
Burnap RL, Nambudiri R, Holland S. Regulation of the carbon-concentrating mechanism in the cyanobacterium Synechocystis sp. PCC6803 in response to changing light intensity and inorganic carbon availability. PHOTOSYNTHESIS RESEARCH 2013; 118:115-124. [PMID: 23990371 DOI: 10.1007/s11120-013-9912-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 08/06/2013] [Indexed: 06/02/2023]
Abstract
Photosynthetic organisms possess regulatory mechanisms to balance the various inputs of photosynthesis in a manner that minimizes over-excitation of the light-driven electron transfer apparatus, while maximizing the reductive assimilation of inorganic nutrients, most importantly inorganic carbon (Ci). Accordingly, the regulatory interactions coordinating responses to fluctuating light and responses to Ci availability are of fundamental significance. The inducible high affinity carbon-concentrating mechanism (CCM) in the cyanobacterium Synechocystis sp. PCC6803 has been studied in order to understand how it is integrated with the light and dark reactions of photosynthesis. To probe genetic regulatory mechanisms, genomic DNA microarrays were used to survey for differences in the expression of genes in response to a shift to high light conditions under conditions of either high or low Ci availability. Discrepancies in published experiments exist regarding the extent to which genes for the CCM are upregulated in response to high light treatment. These discrepancies may be due to critical differences in Ci availability existing during the different high light experiments. The present microarray experiments reexamine this by comparing high light treatment under two different Ci regimes: bubbling with air and bubbling with air enriched with CO2. While some transcriptional responses such as the downregulation of antenna proteins are quite similar, pronounced differences exist with respect to the differential expression of CCM and affiliated genes. The results are discussed in the context of a recent analysis revealing that small molecules that are intermediates of the light and dark reaction photosynthetic metabolism act as allosteric effectors of the DNA-binding proteins which modulate the expression of the CCM genes.
Collapse
Affiliation(s)
- Robert L Burnap
- Microbiology and Molecular Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, OK, 74078, USA,
| | | | | |
Collapse
|
27
|
Rae BD, Long BM, Badger MR, Price GD. Functions, compositions, and evolution of the two types of carboxysomes: polyhedral microcompartments that facilitate CO2 fixation in cyanobacteria and some proteobacteria. Microbiol Mol Biol Rev 2013; 77:357-79. [PMID: 24006469 PMCID: PMC3811607 DOI: 10.1128/mmbr.00061-12] [Citation(s) in RCA: 242] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyanobacteria are the globally dominant photoautotrophic lineage. Their success is dependent on a set of adaptations collectively termed the CO2-concentrating mechanism (CCM). The purpose of the CCM is to support effective CO2 fixation by enhancing the chemical conditions in the vicinity of the primary CO2-fixing enzyme, D-ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), to promote the carboxylase reaction and suppress the oxygenase reaction. In cyanobacteria and some proteobacteria, this is achieved by encapsulation of RubisCO within carboxysomes, which are examples of a group of proteinaceous bodies called bacterial microcompartments. Carboxysomes encapsulate the CO2-fixing enzyme within the selectively permeable protein shell and simultaneously encapsulate a carbonic anhydrase enzyme for CO2 supply from a cytoplasmic bicarbonate pool. These bodies appear to have arisen twice and undergone a process of convergent evolution. While the gross structures of all known carboxysomes are ostensibly very similar, with shared gross features such as a selectively permeable shell layer, each type of carboxysome encapsulates a phyletically distinct form of RubisCO enzyme. Furthermore, the specific proteins forming structures such as the protein shell or the inner RubisCO matrix are not identical between carboxysome types. Each type has evolutionarily distinct forms of the same proteins, as well as proteins that are entirely unrelated to one another. In light of recent developments in the study of carboxysome structure and function, we present this review to summarize the knowledge of the structure and function of both types of carboxysome. We also endeavor to cast light on differing evolutionary trajectories which may have led to the differences observed in extant carboxysomes.
Collapse
Affiliation(s)
- Benjamin D Rae
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | | | | | | |
Collapse
|
28
|
Carbon availability affects diurnally controlled processes and cell morphology of Cyanothece 51142. PLoS One 2013; 8:e56887. [PMID: 23457634 PMCID: PMC3574086 DOI: 10.1371/journal.pone.0056887] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/17/2013] [Indexed: 11/25/2022] Open
Abstract
Cyanobacteria are oxygenic photoautotrophs notable for their ability to utilize atmospheric CO2 as the major source of carbon. The prospect of using cyanobacteria to convert solar energy and high concentrations of CO2 efficiently into biomass and renewable energy sources has sparked substantial interest in using flue gas from coal-burning power plants as a source of inorganic carbon. However, in order to guide further advances in this area, a better understanding of the metabolic changes that occur under conditions of high CO2 is needed. To determine the effect of high CO2 on cell physiology and growth, we analyzed the global transcriptional changes in the unicellular diazotrophic cyanobacterium Cyanothece 51142 grown in 8% CO2-enriched air. We found a concerted response of genes related to photosynthesis, carbon metabolism, respiration, nitrogen fixation, ribosome biosynthesis, and the synthesis of nucleotides and structural cell wall polysaccharides. The overall response to 8% CO2 in Cyanothece 51142 involves different strategies, to compensate for the high C/N ratio during both phases of the diurnal cycle. Our analyses show that high CO2 conditions trigger the production of carbon-rich compounds and stimulate processes such as respiration and nitrogen fixation. In addition, we observed that high levels of CO2 affect fundamental cellular processes such as cell growth and dramatically alter the intracellular morphology. This study provides novel insights on how diurnal and developmental rhythms are integrated to facilitate adaptation to high CO2 in Cyanothece 51142.
Collapse
|
29
|
Price GD, Pengelly JJL, Forster B, Du J, Whitney SM, von Caemmerer S, Badger MR, Howitt SM, Evans JR. The cyanobacterial CCM as a source of genes for improving photosynthetic CO2 fixation in crop species. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:753-68. [PMID: 23028015 DOI: 10.1093/jxb/ers257] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Crop yields need to nearly double over the next 35 years to keep pace with projected population growth. Improving photosynthesis, via a range of genetic engineering strategies, has been identified as a promising target for crop improvement with regard to increased photosynthetic yield and better water-use efficiency (WUE). One approach is based on integrating components of the highly efficient CO(2)-concentrating mechanism (CCM) present in cyanobacteria (blue-green algae) into the chloroplasts of key C(3) crop plants, particularly wheat and rice. Four progressive phases towards engineering components of the cyanobacterial CCM into C(3) species can be envisaged. The first phase (1a), and simplest, is to consider the transplantation of cyanobacterial bicarbonate transporters to C(3) chloroplasts, by host genomic expression and chloroplast targeting, to raise CO(2) levels in the chloroplast and provide a significant improvement in photosynthetic performance. Mathematical modelling indicates that improvements in photosynthesis as high as 28% could be achieved by introducing both of the single-gene, cyanobacterial bicarbonate transporters, known as BicA and SbtA, into C(3) plant chloroplasts. Part of the first phase (1b) includes the more challenging integration of a functional cyanobacterial carboxysome into the chloroplast by chloroplast genome transformation. The later three phases would be progressively more elaborate, taking longer to engineer other functional components of the cyanobacterial CCM into the chloroplast, and targeting photosynthetic and WUE efficiencies typical of C(4) photosynthesis. These later stages would include the addition of NDH-1-type CO(2) pumps and suppression of carbonic anhydrase and C(3) Rubisco in the chloroplast stroma. We include a score card for assessing the success of physiological modifications gained in phase 1a.
Collapse
Affiliation(s)
- G Dean Price
- Molecular Plant Physiology Cluster, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Chua JPS, Wallace EJS, Yardley JA, Duncan EJ, Dearden PK, Summerfield TC. Gene expression indicates a zone of heterocyst differentiation within the thallus of the cyanolichen Pseudocyphellaria crocata. THE NEW PHYTOLOGIST 2012; 196:862-872. [PMID: 22931432 DOI: 10.1111/j.1469-8137.2012.04272.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 07/11/2012] [Indexed: 06/01/2023]
Abstract
Development of the symbiotic association in the bipartite lichen Pseudocyphellaria crocata was investigated by characterizing two regions of the thallus. Thallus organization was examined using microscopy. A HIP1-based differential display technique was modified for use on Nostoc strains, including lichenized strains. Northern hybridization and quantitative real-time polymerase chain reaction were used to confirm differential display results, and determine expression levels of key cyanobacterial genes. Photosystem II yield across the thallus was measured using pulse-amplitude modulated fluorescence. Microscopy revealed structural differences in the thallus margins compared with the centre and identified putative heterocysts in both regions. Differential display identified altered transcript levels in both Nostoc punctiforme and a lichenized Nostoc strain. Transcript abundance of cox2, atpA, and ribA was increased in the thallus margin compared with the centre. Expression of cox2 is heterocyst specific and expression of other heterocyst-specific genes (hetR and nifK) was elevated in the margin, whereas, expression of psbB and PSII yield were not. Structural organization of the thallus margin differed from the centre. Both regions contained putative heterocysts but gene expression data indicated increased heterocyst differentiation in the margins where photosystem II yield was decreased. This is consistent with a zone of heterocyst differentiation within the thallus margin.
Collapse
Affiliation(s)
- Jocelyn P S Chua
- Department of Botany, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Emma J S Wallace
- Department of Botany, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Jessica A Yardley
- Department of Botany, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Elizabeth J Duncan
- National Research Centre for Growth and Development and Genetics Otago, Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Peter K Dearden
- National Research Centre for Growth and Development and Genetics Otago, Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Tina C Summerfield
- Department of Botany, University of Otago, PO Box 56, Dunedin, New Zealand
| |
Collapse
|
31
|
McEwen JT, Atsumi S. Alternative biofuel production in non-natural hosts. Curr Opin Biotechnol 2012; 23:744-50. [DOI: 10.1016/j.copbio.2011.12.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/16/2011] [Accepted: 12/16/2011] [Indexed: 11/16/2022]
|
32
|
Low cellular P-quota and poor metabolic adaptations of the freshwater cyanobacterium Anabaena fertilissima Rao during Pi-limitation. Antonie van Leeuwenhoek 2012; 103:277-91. [PMID: 22968428 DOI: 10.1007/s10482-012-9808-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 09/04/2012] [Indexed: 01/03/2023]
Abstract
Anabaena fertilissima is a filamentous freshwater N(2)-fixing cyanobacterium, isolated from a paddy field. Growth of the cyanobacterium was limited by the non-availability of inorganic phosphate (Pi) in the growth medium and was found to be directly related to the cellular P quota, which declined rapidly in Pi-deficient cells. To overcome Pi-deficiency, cells induced both cell-bound and cell-free alkaline phosphatase activities (APase). The activity of cell-bound APase was rapid and 5-6 times higher than that of the cell-free APase activity. Native gel electrophoresis revealed the presence of two APase activity bands for both the cell bound and cell-free APase (Mr ≈42 and 34 kDa). For Pi-deficient cells, APase activity was inversely related to cellular P-quota. In A. fertilissima phosphate uptake was facilitated by single high-affinity phosphate transporter (K ( s ), 4.54 μM; V(max), 4.84 μmol mg protein(-1) min(-1)). Pi-deficiency severely reduced the photosynthetic rate, respiration rate and nitrate uptake, as well as the activities of nitrate reductase, nitrite reductase and nitrogenase enzymes. In photosynthesis, PSII activity was maximally inhibited, followed by PSI and whole chain activities. Transcript levels of five key glycolytic enzymes showed the poor adaptability of the cyanobacterium to switch its metabolic activity to PPi-dependent enzyme variants, which has rather constant cellular concentrations.
Collapse
|
33
|
Rae BD, Long BM, Badger MR, Price GD. Structural determinants of the outer shell of β-carboxysomes in Synechococcus elongatus PCC 7942: roles for CcmK2, K3-K4, CcmO, and CcmL. PLoS One 2012; 7:e43871. [PMID: 22928045 PMCID: PMC3425506 DOI: 10.1371/journal.pone.0043871] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 07/27/2012] [Indexed: 02/02/2023] Open
Abstract
Cyanobacterial CO(2)-fixation is supported by a CO(2)-concentrating mechanism which improves photosynthesis by saturating the primary carboxylating enzyme, ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO), with its preferred substrate CO(2). The site of CO(2)-concentration is a protein bound micro-compartment called the carboxysome which contains most, if not all, of the cellular RuBisCO. The shell of β-type carboxysomes is thought to be composed of two functional layers, with the inner layer involved in RuBisCO scaffolding and bicarbonate dehydration, and the outer layer in selective permeability to dissolved solutes. Here, four genes (ccmK2-4, ccmO), whose products were predicted to function in the outer shell layer of β-carboxysomes from Synechococcus elongatus PCC 7942, were investigated by analysis of defined genetic mutants. Deletion of the ccmK2 and ccmO genes resulted in severe high-CO(2)-requiring mutants with aberrant carboxysomes, whilst deletion of ccmK3 or ccmK4 resulted in cells with wild-type physiology and normal ultrastructure. However, a tandem deletion of ccmK3-4 resulted in cells with wild-type carboxysome structure, but physiologically deficient at low CO(2) conditions. These results revealed the minimum structural determinants of the outer shell of β-carboxysomes from this strain: CcmK2, CcmO and CcmL. An accessory set of proteins was required to refine the function of the pre-existing shell: CcmK3 and CcmK4. These data suggested a model for the facet structure of β-carboxysomes with CcmL forming the vertices, CcmK2 forming the bulk facet, and CcmO, a "zipper protein," interfacing the edges of carboxysome facets.
Collapse
Affiliation(s)
- Benjamin D. Rae
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Benedict M. Long
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Murray R. Badger
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - G. Dean Price
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| |
Collapse
|
34
|
Eisenhut M, Georg J, Klähn S, Sakurai I, Mustila H, Zhang P, Hess WR, Aro EM. The antisense RNA As1_flv4 in the Cyanobacterium Synechocystis sp. PCC 6803 prevents premature expression of the flv4-2 operon upon shift in inorganic carbon supply. J Biol Chem 2012; 287:33153-62. [PMID: 22854963 PMCID: PMC3460422 DOI: 10.1074/jbc.m112.391755] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The functional relevance of natural cis-antisense transcripts is mostly unknown. Here we have characterized the association of three antisense RNAs and one intergenically encoded noncoding RNA with an operon that plays a crucial role in photoprotection of photosystem II under low carbon conditions in the cyanobacterium Synechocystis sp. PCC 6803. Cyanobacteria show strong gene expression dynamics in response to a shift of cells from high carbon to low levels of inorganic carbon (Ci), but the regulatory mechanisms are poorly understood. Among the most up-regulated genes in Synechocystis are flv4, sll0218, and flv2, which are organized in the flv4-2 operon. The flavodiiron proteins encoded by this operon open up an alternative electron transfer route, likely starting from the QB site in photosystem II, under photooxidative stress conditions. Our expression analysis of cells shifted from high carbon to low carbon demonstrated an inversely correlated transcript accumulation of the flv4-2 operon mRNA and one antisense RNA to flv4, designated as As1_flv4. Overexpression of As1_flv4 led to a decrease in flv4-2 mRNA. The promoter activity of as1_flv4 was transiently stimulated by Ci limitation and negatively regulated by the AbrB-like transcription regulator Sll0822, whereas the flv4-2 operon was positively regulated by the transcription factor NdhR. The results indicate that the tightly regulated antisense RNA As1_flv4 establishes a transient threshold for flv4-2 expression in the early phase after a change in Ci conditions. Thus, it prevents unfavorable synthesis of the proteins from the flv4-2 operon.
Collapse
Affiliation(s)
- Marion Eisenhut
- Department of Biochemistry and Food Science, Plant Physiology and Molecular Biology, University of Turku, Turku FI-20014, Finland
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Daley SME, Kappell AD, Carrick MJ, Burnap RL. Regulation of the cyanobacterial CO2-concentrating mechanism involves internal sensing of NADP+ and α-ketogutarate levels by transcription factor CcmR. PLoS One 2012; 7:e41286. [PMID: 22911771 PMCID: PMC3401165 DOI: 10.1371/journal.pone.0041286] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 06/19/2012] [Indexed: 11/19/2022] Open
Abstract
Inorganic carbon is the major macronutrient required by organisms utilizing oxygenic photosynthesis for autotrophic growth. Aquatic photoautotrophic organisms are dependent upon a CO(2) concentrating mechanism (CCM) to overcome the poor CO(2)-affinity of the major carbon-fixing enzyme, ribulose-bisphosphate carboxylase/oxygenase (Rubisco). The CCM involves the active transport of inorganic forms of carbon (C(i)) into the cell to increase the CO(2) concentration around the active site of Rubisco. It employs both bicarbonate transporters and redox-powered CO(2)-hydration enzymes coupled to membranous NDH-type electron transport complexes that collectively produce C(i) concentrations up to a 1000-fold greater in the cytoplasm compared to the external environment. The CCM is regulated: a high affinity CCM comprised of multiple components is induced under limiting external Ci concentrations. The LysR-type transcriptional regulator CcmR has been shown to repress its own expression along with structural genes encoding high affinity C(i) transporters distributed throughout the genome of Synechocystis sp. PCC 6803. While much has been learned about the structural genes of the CCM and the identity of the transcriptional regulators controlling their expression, little is known about the physiological signals that elicit the induction of the high affinity CCM. Here CcmR is studied to identify metabolites that modulate its transcriptional repressor activity. Using surface plasmon resonance (SPR) α-ketoglutarate (α-KG) and the oxidized form of nicotinamide adenine dinucleotide phosphate (NADP(+)) have been identified as the co-repressors of CcmR. Additionally, ribulose-1,5-bisphosphate (RuBP) and 2-phosphoglycolate (2-PG) have been confirmed as co-activators of CmpR which controls the expression of the ABC-type bicarbonate transporter.
Collapse
Affiliation(s)
- Shawn M. E. Daley
- Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, United States of America
- Department of Biochemistry & Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Anthony D. Kappell
- Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Marla J. Carrick
- Department of Biochemistry & Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Robert L. Burnap
- Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, United States of America
- Department of Biochemistry & Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| |
Collapse
|
36
|
Selection of suitable reference genes for RT-qPCR analyses in cyanobacteria. PLoS One 2012; 7:e34983. [PMID: 22496882 PMCID: PMC3319621 DOI: 10.1371/journal.pone.0034983] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 03/12/2012] [Indexed: 02/02/2023] Open
Abstract
Cyanobacteria are a group of photosynthetic prokaryotes that have a diverse morphology, minimal nutritional requirements and metabolic plasticity that has made them attractive organisms to use in biotechnological applications. The use of these organisms as cell factories requires the knowledge of their physiology and metabolism at a systems level. For the quantification of gene transcripts real-time quantitative polymerase chain reaction (RT-qPCR) is the standard technique. However, to obtain reliable RT-qPCR results the use and validation of reference genes is mandatory. Towards this goal we have selected and analyzed twelve candidate reference genes from three morphologically distinct cyanobacteria grown under routinely used laboratory conditions. The six genes exhibiting less variation in each organism were evaluated in terms of their expression stability using geNorm, NormFinder and BestKeeper. In addition, the minimum number of reference genes required for normalization was determined. Based on the three algorithms, we provide a list of genes for cyanobacterial RT-qPCR data normalization. To our knowledge, this is the first work on the validation of reference genes for cyanobacteria constituting a valuable starting point for future works.
Collapse
|
37
|
Fukuzawa H, Ogawa T, Kaplan A. The Uptake of CO2 by Cyanobacteria and Microalgae. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
38
|
Rae BD, Förster B, Badger MR, Price GD. The CO2-concentrating mechanism of Synechococcus WH5701 is composed of native and horizontally-acquired components. PHOTOSYNTHESIS RESEARCH 2011; 109:59-72. [PMID: 21384181 DOI: 10.1007/s11120-011-9641-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 02/24/2011] [Indexed: 05/30/2023]
Abstract
The cyanobacterial CO(2)-concentrating mechanism (CCM) is an effective adaptation that increases the carbon dioxide (CO(2)) concentration around the primary photosynthetic enzyme Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RuBisCO). α-Cyanobacteria (those containing Form1-A RuBisCO within cso-type α-carboxysomes) have a limited CCM composed of a small number of Ci-transporters whereas β-cyanobacteria (those species containing Form-1B RuBisCO within ccm-type β-carboxysomes) exhibit a more diverse CCM with a greater variety in Ci-transporter complement and regulation. In the coastal species Synechococcus sp. WH5701 (α-cyanobacteria), the minimal α-cyanobacterial CCM has been supplemented with β-cyanobacterial Ci transporters through the process of horizontal gene transfer (HGT). These transporters are transcriptionally regulated in response to external Ci-depletion however this change in transcript abundance is not correlated with a physiological induction. WH5701 exhibits identical physiological responses grown at 4% CO(2) (K (1/2) ≈ 31 μM Ci) and after induction with 0.04% CO(2) (K (1/2) ≈ 29 μM Ci). Insensitivity to external Ci concentration is an unusual characteristic of the WH5701 CCM which is a result of evolution by HGT. Our bioinformatic and physiological data support the hypothesis that WH5701 represents a clade of α-cyanobacterial species in transition from the marine/oligotrophic environment to a coastal/freshwater environment.
Collapse
Affiliation(s)
- Benjamin D Rae
- Division of Plant Science, Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia
| | | | | | | |
Collapse
|
39
|
Long BM, Rae BD, Badger MR, Price GD. Over-expression of the β-carboxysomal CcmM protein in Synechococcus PCC7942 reveals a tight co-regulation of carboxysomal carbonic anhydrase (CcaA) and M58 content. PHOTOSYNTHESIS RESEARCH 2011; 109:33-45. [PMID: 21597987 DOI: 10.1007/s11120-011-9659-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 04/22/2011] [Indexed: 05/19/2023]
Abstract
Carboxysomes, containing the cell's complement of RuBisCO surrounded by a specialized protein shell, are a central component of the cyanobacterial CO(2)-concentrating mechanism. The ratio of two forms of the β-carboxysomal protein CcmM (M58 and M35) may affect the carboxysomal carbonic anhydrase (CcaA) content. We have over-expressed both M35 and M58 in the β-cyanobacterium Synechococcus PCC7942. Over-expression of M58 resulted in a marked increase in the amount of this protein in carboxysomes at the expense of M35, with a concomitant increase in the observed CcaA content of carboxysomes. Conversely, M35 over-expression diminished M58 content of carboxysomes and led to a decrease in CcaA content. Carboxysomes of air-grown wild-type cells contained slightly elevated CcaA and M58 content and slightly lower M35 content compared to their 2% CO(2)-grown counterparts. Over a range of CcmM expression levels, there was a strong correlation between M58 and CcaA content, indicating a constant carboxysomal M58:CcaA stoichiometry. These results also confirm a role for M58 in the recruitment of CcaA into the carboxysome and suggest a tight regulation of M35 and M58 translation is required to produce carboxysomes with an appropriate CA content. Analysis of carboxysomal protein ratios, resulting from the afore-mentioned over-expression studies, revealed that β-carboxysomal protein stoichiometries are relatively flexible. Determination of absolute protein quantities supports the hypothesis that M35 is distributed throughout the β-carboxysome. A modified β-carboxysome packing model is presented.
Collapse
Affiliation(s)
- Benedict M Long
- Molecular Plant Physiology, Plant Science Division, Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia
| | | | | | | |
Collapse
|
40
|
Price GD. Inorganic carbon transporters of the cyanobacterial CO2 concentrating mechanism. PHOTOSYNTHESIS RESEARCH 2011; 109:47-57. [PMID: 21359551 DOI: 10.1007/s11120-010-9608-y] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 12/14/2010] [Indexed: 05/04/2023]
Abstract
Cyanobacteria possess an environmental adaptation known as a CO(2) concentrating mechanism (CCM) that evolved to improve photosynthetic performance, particularly under CO(2)-limiting conditions. The CCM functions to actively transport dissolved inorganic carbon species (Ci; HCO(3)(-) and CO(2)) resulting in accumulation of a pool of HCO(3)(-) within the cell that is then utilised to provide an elevated CO(2) concentration around the primary CO(2) fixing enzyme, ribulose bisphosphate carboxylase-oxygenase (Rubisco). Rubisco is encapsulated in unique micro-compartments known as carboxysomes and also provides the location for elevated CO(2) levels in the cell. Five distinct transport systems for active Ci uptake are known, including two types of Na(+)-dependent HCO(3)(-) transporters (BicA and SbtA), one traffic ATPase (BCT1) for HCO(3)(-) uptake and two CO(2) uptake systems based on modified NADPH dehydrogenase complexes (NDH-I(3) and NDH-I(4)). The genes for a number of these transporters are genetically induced under Ci limitation via transcriptional regulatory processes. The in-membrane topology structures of the BicA and SbtA HCO(3)(-) transporters are now known and this may aid in determining processes related to transporter activation during dark to light transitions or under severe Ci limitation.
Collapse
Affiliation(s)
- G Dean Price
- Molecular Plant Physiology Cluster, Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT, Australia.
| |
Collapse
|
41
|
Schwarz D, Nodop A, Hüge J, Purfürst S, Forchhammer K, Michel KP, Bauwe H, Kopka J, Hagemann M. Metabolic and transcriptomic phenotyping of inorganic carbon acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942. PLANT PHYSIOLOGY 2011; 155:1640-55. [PMID: 21282404 PMCID: PMC3091134 DOI: 10.1104/pp.110.170225] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The amount of inorganic carbon is one of the main limiting environmental factors for photosynthetic organisms such as cyanobacteria. Using Synechococcus elongatus PCC 7942, we characterized metabolic and transcriptomic changes in cells that had been shifted from high to low CO(2) levels. Metabolic phenotyping indicated an activation of glycolysis, the oxidative pentose phosphate cycle, and glycolate metabolism at lowered CO(2) levels. The metabolic changes coincided with a general reprogramming of gene expression, which included not only increased transcription of inorganic carbon transporter genes but also genes for enzymes involved in glycolytic and photorespiratory metabolism. In contrast, the mRNA content for genes from nitrogen assimilatory pathways decreased. These observations indicated that cyanobacteria control the homeostasis of the carbon-nitrogen ratio. Therefore, results obtained from the wild type were compared with the MP2 mutant of Synechococcus 7942, which is defective for the carbon-nitrogen ratio-regulating PII protein. Metabolites and genes linked to nitrogen assimilation were differentially regulated, whereas the changes in metabolite concentrations and gene expression for processes related to central carbon metabolism were mostly similar in mutant and wild-type cells after shifts to low-CO(2) conditions. The PII signaling appears to down-regulate the nitrogen metabolism at lowered CO(2), whereas the specific shortage of inorganic carbon is recognized by different mechanisms.
Collapse
|
42
|
Battchikova N, Vainonen JP, Vorontsova N, Keranen M, Carmel D, Aro EM. Dynamic changes in the proteome of Synechocystis 6803 in response to CO(2) limitation revealed by quantitative proteomics. J Proteome Res 2010; 9:5896-912. [PMID: 20795750 DOI: 10.1021/pr100651w] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyanobacteria developed efficient carbon concentrating mechanisms which significantly improve the photosynthetic performance and survival of cells under limiting CO(2) conditions. Dynamic changes of the Synechocystis proteome to CO(2) limitation were investigated using shotgun LC-MS/MS approach with isobaric tag for relative and absolute quantification (iTRAQ) technique. Synechocystis cells grown at high (3%) CO(2) were shifted to air-level CO(2) followed by protein extraction after 6, 24, and 72 h. About 19% of the cyanobacterial proteome was identified and the expression changes were quantified for 17% of theoretical ORFs. For 76 proteins, up- or down-regulation was found to be significant (more than 1.5 or less than 0.7). Major changes were observed in proteins participating in inorganic carbon uptake, CO(2) fixation, nitrogen transport and assimilation, as well as in the protection of the photosynthetic machinery from excess of light. Further, a number of hypothetical proteins with unknown functions were discovered. In general, the cells appear to acclimate to low CO(2) without a significant stress since the stress-related molecular chaperones were down-regulated and only a minor decline was detected for proteins of phycobilisomes, photosynthetic complexes, and translation machinery. The results of iTRAQ experiment were validated by the Western blot analysis for selected proteins.
Collapse
Affiliation(s)
- Natalia Battchikova
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, Finland.
| | | | | | | | | | | |
Collapse
|
43
|
Jensen SI, Steunou AS, Bhaya D, Kühl M, Grossman AR. In situ dynamics of O2, pH and cyanobacterial transcripts associated with CCM, photosynthesis and detoxification of ROS. ISME JOURNAL 2010; 5:317-28. [PMID: 20740024 DOI: 10.1038/ismej.2010.131] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The relative abundance of transcripts encoding proteins involved in inorganic carbon concentrating mechanisms (CCM), detoxification of reactive oxygen species (ROS) and photosynthesis in the thermophilic cyanobacterium Synechococcus OS-B' was measured in hot spring microbial mats over two diel cycles, and was coupled with in situ determinations of incoming irradiance and microenvironmental dynamics of O(2) and pH. Fluctuations in pH and O(2) in the mats were largely driven by the diel cycle of solar irradiance, with a pH variation from ∼7.0 to ∼9.5, and O(2) levels ranging from anoxia to supersaturation during night and day, respectively. Levels of various transcripts from mat cyanobacteria revealed several patterns that correlated with incident irradiance, O(2) and pH within the mat matrix. Transcript abundances for most genes increased during the morning dark-light transition. Some transcripts remained at a near constant level throughout the light period, whereas others showed an additional increase in abundance as the mat underwent transition from low-to-high light (potentially reflecting changes in O(2) concentration and pH), followed by either a decreased abundance in the early afternoon, or a gradual decline during the early afternoon and into the evening. One specific transcipt, psbA1, was the lowest during mid-day under high irradiance and increased when the light levels declined. We discuss these complex in situ transcriptional patterns with respect to environmental and endogenous cues that might impact and regulate transcription over the diel cycle.
Collapse
Affiliation(s)
- Sheila I Jensen
- Department of Biology, Marine Biological Laboratory, University of Copenhagen, Helsingør, Denmark.
| | | | | | | | | |
Collapse
|
44
|
Leão PN, Vasconcelos MTSD, Vasconcelos VM. Allelopathy in freshwater cyanobacteria. Crit Rev Microbiol 2010; 35:271-82. [PMID: 19863381 DOI: 10.3109/10408410902823705] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Freshwater cyanobacteria produce several bioactive secondary metabolites with diverse chemical structure, which may achieve high concentrations in the aquatic medium when cyanobacterial blooms occur. Some of the compounds released by cyanobacteria have allelopathic properties, influencing the biological processes of other phytoplankton or aquatic plants. These kinds of interactions are more easily detectable under laboratory studies; however their ecological relevance is often debated. Recent research has discovered new allelopathic properties in some cyanobacteria species, new allelochemicals and elucidated some of the allelopathic mechanisms. Ecosystem-level approaches have shed some light on the factors that influence allelopathic interactions, as well as how cyanobacteria may be able to modulate their surrounding environment by means of allelochemical release. Nevertheless, the role of allelopathy in cyanobacteria ecology is still not well understood, and its clarification should benefit from carefully designed field studies, chemical characterization of allelochemicals and new methodological approaches at the "omics" level.
Collapse
Affiliation(s)
- Pedro N Leão
- CIIMAR/CIMAR-LA, Centro Interdisciplinar de Investigação Marinha e Ambiental, Porto, Portugal.
| | | | | |
Collapse
|
45
|
Martin V, Villarreal F, Miras I, Navaza A, Haouz A, González-Lebrero RM, Kaufman SB, Zabaleta E. Recombinant plant gamma carbonic anhydrase homotrimers bind inorganic carbon. FEBS Lett 2009; 583:3425-30. [PMID: 19808034 DOI: 10.1016/j.febslet.2009.09.055] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/18/2009] [Accepted: 09/28/2009] [Indexed: 12/01/2022]
Abstract
Gamma carbonic anhydrases (gammaCA) are widespread in Prokaryotes. In Eukaryotes, homologous genes were found only in plant genomes. In Arabidopsis and maize, the corresponding gene products are subunits of mitochondrial Complex I. At present, only gammaCA homotrimers of Methanosarcina thermophila (CAM) show reversible carbon dioxide (CO(2)) hydration activity. In the present work, it is shown that recombinant plant gammaCA2 could form homotrimers and bind H(14)CO(3)(-). However, they are unable to catalyse the reversible hydration of CO(2). These results suggest that plant gammaCAs do not act as carbonic anhydrases but with a related activity possibly contributing to recycle CO(2) in the context of photorespiration.
Collapse
Affiliation(s)
- Victoria Martin
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), CC 1245, 7600 Mar del Plata, Argentina
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Buxton L, Badger M, Ralph P. EFFECTS OF MODERATE HEAT STRESS AND DISSOLVED INORGANIC CARBON CONCENTRATION ON PHOTOSYNTHESIS AND RESPIRATION OF SYMBIODINIUM SP. (DINOPHYCEAE) IN CULTURE AND IN SYMBIOSIS(1). JOURNAL OF PHYCOLOGY 2009; 45:357-365. [PMID: 27033814 DOI: 10.1111/j.1529-8817.2009.00659.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The influence of temperature and inorganic carbon (Ci ) concentration on photosynthesis was examined in whole corals and samples of cultured symbiotic dinoflagellates (Symbiodinium sp.) using combined measurements from a membrane inlet mass spectrometer and chl a fluorometer. In whole corals, O2 production at 26°C was significantly limited at Ci concentrations below ambient seawater (∼2.2 mM). Further additions of Ci up to ∼10 mM caused no further stimulation of oxygenic photosynthesis. Following exposure to 30°C (2 d), net oxygen production decreased significantly in whole corals, as a result of reduced production of photosynthetically derived oxygen rather than increased host consumption. Whole corals maintained a rate of oxygen evolution around eight times lower than cultured Symbiodinium sp. at inorganic carbon concentrations <2 mM, but cultures displayed greater levels of photoinhibition following heat treatment (30°C, 2 d). Whole corals and cultured zooxanthellae differed considerably in their responses to Ci concentration and moderate heat stress, demonstrating that cultured Symbiodinium make an incongruous model for those in hospite. Reduced net oxygen evolution, in whole corals, under conditions of low Ci (<2 mM) has been interpreted in terms of possible sink limitation leading to increased nonphotochemical energy dissipation. The advantages of combined measurement of net gas exchange and fluorometry offered by this method are discussed.
Collapse
Affiliation(s)
- Lucy Buxton
- Department of Environmental Sciences, Institute for Water and Environmental Resource Management, University of Technology Sydney, Sydney, New South Wales 2007, AustraliaARC Centre of Excellence in Plant Energy Biology, Molecular Plant Physiology Group, Research School of Biological Sciences, The Australian National University, Canberra, Australian Capital Territory, AustraliaDepartment of Environmental Sciences, Institute for Water and Environmental Resource Management, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Murray Badger
- Department of Environmental Sciences, Institute for Water and Environmental Resource Management, University of Technology Sydney, Sydney, New South Wales 2007, AustraliaARC Centre of Excellence in Plant Energy Biology, Molecular Plant Physiology Group, Research School of Biological Sciences, The Australian National University, Canberra, Australian Capital Territory, AustraliaDepartment of Environmental Sciences, Institute for Water and Environmental Resource Management, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Peter Ralph
- Department of Environmental Sciences, Institute for Water and Environmental Resource Management, University of Technology Sydney, Sydney, New South Wales 2007, AustraliaARC Centre of Excellence in Plant Energy Biology, Molecular Plant Physiology Group, Research School of Biological Sciences, The Australian National University, Canberra, Australian Capital Territory, AustraliaDepartment of Environmental Sciences, Institute for Water and Environmental Resource Management, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| |
Collapse
|
47
|
Yamano T, Fukuzawa H. Carbon-concentrating mechanism in a green alga,Chlamydomonas reinhardtii, revealed by transcriptome analyses. J Basic Microbiol 2009; 49:42-51. [DOI: 10.1002/jobm.200800352] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
48
|
Sowell SM, Wilhelm LJ, Norbeck AD, Lipton MS, Nicora CD, Barofsky DF, Carlson CA, Smith RD, Giovanonni SJ. Transport functions dominate the SAR11 metaproteome at low-nutrient extremes in the Sargasso Sea. ISME JOURNAL 2008; 3:93-105. [PMID: 18769456 DOI: 10.1038/ismej.2008.83] [Citation(s) in RCA: 245] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The northwestern Sargasso Sea undergoes annual cycles of productivity with increased production in spring corresponding to periods of upwelling, and oligotrophy in summer and autumn, when the water column becomes highly stratified. The biological productivity of this region is reduced during stratified periods as a result of low concentrations of phosphorus and nitrogen in the euphotic zone. To better understand the mechanisms of microbial survival in this oligotrophic environment, we used capillary liquid chromatography (LC)-tandem mass spectrometry to detect microbial proteins in surface samples collected in September 2005. A total of 2215 peptides that mapped to 236 SAR11 proteins, 1911 peptides that mapped to 402 Prochlorococcus proteins and 2407 peptides that mapped to 404 Synechococcus proteins were detected. Mass spectra from SAR11 periplasmic substrate-binding proteins accounted for a disproportionately large fraction of the peptides detected, consistent with observations that these extremely small cells devote a large proportion of their volume to periplasm. Abundances were highest for periplasmic substrate-binding proteins for phosphate, amino acids, phosphonate, sugars and spermidine. Proteins implicated in the prevention of oxidative damage and protein refolding were also abundant. Our findings support the view that competition for multiple nutrients in oligotrophic systems is extreme, but nutrient flux is sufficient to sustain microbial community activity.
Collapse
Affiliation(s)
- Sarah M Sowell
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Yamano T, Miura K, Fukuzawa H. Expression analysis of genes associated with the induction of the carbon-concentrating mechanism in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2008; 147:340-54. [PMID: 18322145 PMCID: PMC2330288 DOI: 10.1104/pp.107.114652] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 02/24/2008] [Indexed: 05/19/2023]
Abstract
Acclimation to varying CO2 concentrations and light intensities is associated with the monitoring of environmental changes by controlling genetic and physiological responses through CO2 and light signal transduction. While CO2 and light signals are indispensable for photosynthesis, and these environmental factors have been proposed as strongly associated with each other, studies linking these components are largely limited to work on higher plants. In this study, we examined the physiological characteristics of a green alga, Chlamydomonas reinhardtii, exposed to various light intensities or CO2 concentrations. Acclimation to CO2-limiting conditions by Chlamydomonas requires the induction of a carbon-concentrating mechanism (CCM) to allow the uptake of inorganic carbon (Ci) and increase the affinity for Ci. We revealed that the induction of the CCM is not solely dependent on absolute environmental Ci concentrations but is also affected by light intensity. Using a cDNA array containing 10,368 expressed sequence tags, we also obtained global expression profiles related to the physiological responses. The induction of several CCM-associated genes was strongly affected by high light as well as CO2 concentrations. We identified novel candidates for Ci transporters and CO2-responsive regulatory factors whose expression levels were significantly increased during the induction of the CCM.
Collapse
Affiliation(s)
- Takashi Yamano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | | | | |
Collapse
|
50
|
Price GD, Badger MR, Woodger FJ, Long BM. Advances in understanding the cyanobacterial CO2-concentrating-mechanism (CCM): functional components, Ci transporters, diversity, genetic regulation and prospects for engineering into plants. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:1441-61. [PMID: 17578868 DOI: 10.1093/jxb/erm112] [Citation(s) in RCA: 377] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cyanobacteria have evolved a significant environmental adaptation, known as a CO(2)-concentrating-mechanism (CCM), that vastly improves photosynthetic performance and survival under limiting CO(2) concentrations. The CCM functions to transport and accumulate inorganic carbon actively (Ci; HCO(3)(-), and CO(2)) within the cell where the Ci pool is utilized to provide elevated CO(2) concentrations around the primary CO(2)-fixing enzyme, ribulose bisphosphate carboxylase-oxygenase (Rubisco). In cyanobacteria, Rubisco is encapsulated in unique micro-compartments known as carboxysomes. Cyanobacteria can possess up to five distinct transport systems for Ci uptake. Through database analysis of some 33 complete genomic DNA sequences for cyanobacteria it is evident that considerable diversity exists in the composition of transporters employed, although in many species this diversity is yet to be confirmed by comparative phenomics. In addition, two types of carboxysomes are known within the cyanobacteria that have apparently arisen by parallel evolution, and considerable progress has been made towards understanding the proteins responsible for carboxysome assembly and function. Progress has also been made towards identifying the primary signal for the induction of the subset of CCM genes known as CO(2)-responsive genes, and transcriptional regulators CcmR and CmpR have been shown to regulate these genes. Finally, some prospects for introducing cyanobacterial CCM components into higher plants are considered, with the objective of engineering plants that make more efficient use of water and nitrogen.
Collapse
Affiliation(s)
- G Dean Price
- Molecular Plant Physiology Group, Research School of Biological Sciences, Australian National University, PO Box 475, Canberra, ACT 0200, Australia.
| | | | | | | |
Collapse
|