1
|
Tibocha-Bonilla JD, Zuñiga C, Godoy-Silva RD, Zengler K. Advances in metabolic modeling of oleaginous microalgae. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:241. [PMID: 30202436 PMCID: PMC6124020 DOI: 10.1186/s13068-018-1244-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/27/2018] [Indexed: 06/08/2023]
Abstract
Production of biofuels and bioenergy precursors by phototrophic microorganisms, such as microalgae and cyanobacteria, is a promising alternative to conventional fuels obtained from non-renewable resources. Several species of microalgae have been investigated as potential candidates for the production of biofuels, for the most part due to their exceptional metabolic capability to accumulate large quantities of lipids. Constraint-based modeling, a systems biology approach that accurately predicts the metabolic phenotype of phototrophs, has been deployed to identify suitable culture conditions as well as to explore genetic enhancement strategies for bioproduction. Core metabolic models were employed to gain insight into the central carbon metabolism in photosynthetic microorganisms. More recently, comprehensive genome-scale models, including organelle-specific information at high resolution, have been developed to gain new insight into the metabolism of phototrophic cell factories. Here, we review the current state of the art of constraint-based modeling and computational method development and discuss how advanced models led to increased prediction accuracy and thus improved lipid production in microalgae.
Collapse
Affiliation(s)
- Juan D. Tibocha-Bonilla
- Grupo de Investigación en Procesos Químicos y Bioquímicos, Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Av. Carrera 30 No. 45-03, Bogotá, D.C. Colombia
| | - Cristal Zuñiga
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760 USA
| | - Rubén D. Godoy-Silva
- Grupo de Investigación en Procesos Químicos y Bioquímicos, Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Av. Carrera 30 No. 45-03, Bogotá, D.C. Colombia
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0760 USA
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412 USA
- Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0436 USA
| |
Collapse
|
2
|
Ruan Z, Raven JA, Giordano M. In Synechococcus sp. competition for energy between assimilation and acquisition of C and those of N only occurs when growth is light limited. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3829-3839. [PMID: 28369501 DOI: 10.1093/jxb/erx074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The carbon-concentrating mechanisms (CCMs) of cyanobacteria counteract the low CO2 affinity and CO2:O2 selectivities of the Rubisco of these photolithotrophs and the relatively low oceanic CO2 availability. CCMs have a significant energy cost; if light is limiting, the use of N sources whose assimilation demands less energy could permit a greater investment of energy into CCMs and inorganic C (Ci) assimilation. To test this, we cultured Synechococcus sp. UTEX LB 2380 under either N or energy limitation, in the presence of NO3- or NH4+. When growth was energy-limited, NH4+-grown cells had a 1.2-fold higher growth rate, 1.3-fold higher dissolved inorganic carbon (DIC)-saturated photosynthetic rate, 19% higher linear electron transfer, 80% higher photosynthetic 1/K1/2(DIC), 2.0-fold greater slope of the linear part of the photosynthesis versus DIC curve, 3.5-fold larger intracellular Ci pool, and 2.3-fold higher Zn quota than NO3--grown cells. When energy was not limiting growth, there were not differences between NH4+- and NO3--grown cells, except for higher linear electron transfer and larger intracellular Ci pool.We conclude that, when energy limits growth, cells that use the cheaper N source divert energy from N assimilation to C acquisition and assimilation; this does not happen when energy is not limiting.
Collapse
Affiliation(s)
- Zuoxi Ruan
- Marine Biology Institute, Science Center, Shantou University, Shantou, Guangdong 515063, China
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona 60131, Italy
| | - John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo NSW 2007, Australia
| | - Mario Giordano
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona 60131, Italy
- Institute of Microbiology ASCR, Algatech, Trebon, Czech Republic
- National Research Council, Institute of Marine Science, Venezia, Italy
| |
Collapse
|
3
|
Ruan Z, Giordano M. The use of NH 4+ rather than NO 3- affects cell stoichiometry, C allocation, photosynthesis and growth in the cyanobacterium Synechococcus sp. UTEX LB 2380, only when energy is limiting. PLANT, CELL & ENVIRONMENT 2017; 40:227-236. [PMID: 27982443 DOI: 10.1111/pce.12858] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/21/2016] [Accepted: 10/26/2016] [Indexed: 06/06/2023]
Abstract
The assimilation of N-NO3- requires more energy than that of N-NH4+ . This becomes relevant when energy is limiting and may impinge differently on cell energy budget depending on depth, time of the day and season. We hypothesize that N-limited and energy-limited cells of the oceanic cyanobacterium Synechococcus sp. differ in their response to the N source with respect to growth, elemental stoichiometry and carbon allocation. Under N limitation, cells retained almost absolute homeostasis of elemental and organic composition, and the use of NH4+ did not stimulate growth. When energy was limiting, however, Synechococcus grew faster in NH4+ than in NO3- and had higher C (20%), N (38%) and S (30%) cell quotas. Furthermore, more C was allocated to protein, whereas the carbohydrate and lipid pool size did not change appreciably. Energy limitation also led to a higher photosynthetic rate relative to N limitation. We interpret these results as an indication that, under energy limitation, the use of the least expensive N source allowed a spillover of the energy saved from N assimilation to the assimilation of other nutrients. The change in elemental stoichiometry influenced C allocation, inducing an increase in cell protein, which resulted in a stimulation of photosynthesis and growth.
Collapse
Affiliation(s)
- Zuoxi Ruan
- Marine Biology Institute, Science Center, Shantou University, Shantou, Guangdong, 515063, China
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, 60131, Italy
| | - Mario Giordano
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, 60131, Italy
- Institute of Microbiology ASCR, Algatech, Trebon, Czech Republic
- National Research Council, Institute of Marine Science, Venezia, Italy
| |
Collapse
|
4
|
Touloupakis E, Benavides AMS, Cicchi B, Torzillo G. Growth and hydrogen production of outdoor cultures of Synechocystis PCC 6803. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
5
|
Yan R, Zhang Z, Zeng Q, Zhu D, Chu J. Characterization of energy conversion of Synechococcus sp. PCC7942 under photoautotrophic conditions based on metabolic flux and chlorophyll fluorescence analysis. BIOTECHNOL BIOPROC E 2011. [DOI: 10.1007/s12257-010-0102-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
6
|
A model-based method for investigating bioenergetic processes in autotrophically growing eukaryotic microalgae: Application to the green algae Chlamydomonas reinhardtii. Biotechnol Prog 2011; 27:631-40. [DOI: 10.1002/btpr.596] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 01/06/2011] [Indexed: 11/07/2022]
|
7
|
Abstract
To provide an insight into the heterotrophic metabolism of cyanobacteria, a proteomic approach has been employed with the model organism Synechocystis sp. PCC 6803. The soluble proteins from Synechocystis grown under photoautotrophic and light-activated heterotrophic conditions were separated by 2-DE and identified by MALDI-MS or LC-MS/MS analysis. 2-DE gels made using narrow- and micro-range IPG strips allowed quantitative comparison of more than 900 spots. Out of 67 abundant protein spots identified, 13 spots were increased and 9 decreased under heterotrophy, representing all the major fold changes. Proteomic alterations and activity levels of selected enzymes indicate a shift in the central carbon metabolism in response to trophic change. The significant reduction in light-saturated rate of photosynthesis as well as in the expression levels of rubisco and CO(2)-concentrating mechanism proteins under heterotrophy indicates the down-regulation of the photosynthetic machinery. Alterations in the expression level of proteins involved in carbon utilization pathways refer to enhanced glycolysis, oxidative pentose phosphate pathway as well as tricarboxylic acid cycle under heterotrophy. Proteomic evidences also suggest an enhanced biosynthesis of amino acids such as histidine and serine during heterotrophic growth.
Collapse
Affiliation(s)
- Dominic Kurian
- Laboratory of Plant Physiology and Molecular Biology, Department of Biology, University of Turku, Turku, Finland
| | | | | |
Collapse
|
8
|
Herrero A, Muro-Pastor AM, Valladares A, Flores E. Cellular differentiation and the NtcA transcription factor in filamentous cyanobacteria. FEMS Microbiol Rev 2004; 28:469-87. [PMID: 15374662 DOI: 10.1016/j.femsre.2004.04.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 12/31/2003] [Accepted: 04/04/2004] [Indexed: 10/26/2022] Open
Abstract
Some filamentous cyanobacteria can undergo a variety of cellular differentiation processes that permit their better adaptation to certain environmental conditions. These processes include the differentiation of hormogonia, short filaments aimed at the dispersal of the organism in the environment, of akinetes, cells resistant to various stress conditions, and of heterocysts, cells specialized in the fixation of atmospheric nitrogen in oxic environments. NtcA is a transcriptional regulator that operates global nitrogen control in cyanobacteria by activating (and in some cases repressing) many genes involved in nitrogen assimilation. NtcA is required for the triggering of heterocyst differentiation and for subsequent steps of its development and function. This requirement is based on the role of NtcA as an activator of the expression of hetR and other multiple genes at specific steps of the differentiation process. The products of these genes effect development as well as the distinct metabolism of the mature heterocyst. The different features found in the NtcA-dependent promoters, together with the cellular level of active NtcA protein, should have a role in the determination of the hierarchy of gene activation during the process of heterocyst differentiation.
Collapse
Affiliation(s)
- Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Avda. Américo Vespucio s/n, E-41092 Seville, Spain.
| | | | | | | |
Collapse
|
9
|
Cogne G, Gros JB, Dussap CG. Identification of a metabolic network structure representative of Arthrospira (spirulina) platensis metabolism. Biotechnol Bioeng 2004; 84:667-76. [PMID: 14595779 DOI: 10.1002/bit.10808] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A comprehensive network structure for the autotrophic growth of Arthrospira platensis is proposed. The metabolic network was built up with 121 reactions and 134 metabolites including biomass synthesis, production of a growth-associated exopolysaccharide, and energy aspects. The model supports the existence of a metabolic shunt of PEP to pyruvate through PEP carboxylase, NAD(+)-dependent malate dehydrogenase and malic enzyme to convert NADH,H(+) into NADPH,H(+). A limit in Arthrospira growth metabolism due to NADH,H(+) balancing is evidenced, explaining why the maximal light-dependent mass yield of the growth-associated exopolysaccharide was 0.51 kg EPS kg(-1) biomass, consistent with experimental results.
Collapse
Affiliation(s)
- Guillaume Cogne
- Laboratoire de Génie Chimique et Biochimique, Université Blaise Pascal, CUST, 24 avenue des Landais, BP 206, 63174 Aubière-Cédex, France.
| | | | | |
Collapse
|
10
|
Vázquez-Bermúdez MF, Herrero A, Flores E. 2-Oxoglutarate increases the binding affinity of the NtcA (nitrogen control) transcription factor for the Synechococcus glnA promoter. FEBS Lett 2002; 512:71-4. [PMID: 11852054 DOI: 10.1016/s0014-5793(02)02219-6] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The cyanobacterial NtcA global nitrogen regulator belongs to the catabolite activator protein (CAP) family and activates transcription of nitrogen assimilation genes in response to nitrogen step-down. The binding affinity of NtcA towards a DNA fragment carrying the promoter of the glnA gene from Synechococcus sp. PCC 7942, analyzed in vitro by band-shift assay, was increased five-fold by 2-oxoglutarate in the presence of Mg(2+) ions. The 2-oxoglutarate effect peaked at about 0.6 mM, a rather physiological concentration for this compound under nitrogen-limiting conditions, and could be partially reproduced by 3-oxoglutarate but not by oxaloacetate or glutamate. These results suggest 2-oxoglutarate as a signal of the C to N balance of the cells to regulate NtcA activity and provide a new example of regulation in the versatile CAP family of proteins.
Collapse
Affiliation(s)
- María Félix Vázquez-Bermúdez
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Avda. Américo Vespucio s/n, E-41092, Sevilla, Spain.
| | | | | |
Collapse
|
11
|
Affiliation(s)
- A Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, E-41092 Seville, Spain
| | | | | |
Collapse
|
12
|
Lee HM, Flores E, Forchhammer K, Herrero A, Tandeau De Marsac N. Phosphorylation of the signal transducer PII protein and an additional effector are required for the PII-mediated regulation of nitrate and nitrite uptake in the Cyanobacterium synechococcus sp. PCC 7942. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:591-600. [PMID: 10632730 DOI: 10.1046/j.1432-1327.2000.01043.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the cyanobacterium Synechococcus sp. strain PCC 7942, the phosphorylation states of the signal transducer PII protein (GlnB) can change rapidly depending on the nitrogen and carbon supply. A PII-null mutant (MP2) shows no ammonium-dependent inhibition of the nitrate and nitrite uptake, in contrast to the wild-type. New mutants with different types of PII, which may mimic either the phosphorylated (GlnBS49E or GlnBS49D) or unphosphorylated (GlnBS49A) form of the protein, were constructed using site-directed in vitro mutagenesis. Mutant MP2-A (GlnBS49A) grew poorly using nitrate as a nitrogen source and was unable to take up nitrate supplied at 100 microM, even in the absence of externally added ammonium. Mutants MP2-D and MP2-E (GlnBS49D and GlnBS49E, respectively), however, showed nitrate-dependent growth and regulation of nitrate uptake by ammonium, as in the wild-type. Characterization of the mutants also included an analysis of nitrite uptake and of the levels of the nir (nitrate/nitrite assimilation) operon transcripts, the presence of NrtA (nitrate/nitrite transport binding protein), and nitrate and nitrite reductase activities. In vitro, no significant difference was observed in the cooperative binding of ATP and 2-oxoglutarate between the wild-type and the unphosphorylated or phosphorylated-like forms of the mutant PII proteins. The results obtained indicate that both unphosphorylated and phosphorylated-like forms of PII are able to inhibit nitrate uptake in the presence of ammonium, but the unphosphorylated form also has a negative effect in the absence of this nitrogen source. Therefore, an additional effector, possibly 2-oxoglutarate, is required for the PII protein to relieve inhibition of nitrate uptake in the absence of ammonium.
Collapse
Affiliation(s)
- H M Lee
- Département de Biochimie et Génétique Moléculaire, Unité de Physiologie Microbienne, Paris, France
| | | | | | | | | |
Collapse
|
13
|
Vázquez-Bermúdez MF, Herrero A, Flores E. Uptake of 2-oxoglutarate in Synechococcus strains transformed with the Escherichia coli kgtP gene. J Bacteriol 2000; 182:211-5. [PMID: 10613883 PMCID: PMC94260 DOI: 10.1128/jb.182.1.211-215.2000] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A number of cyanobacteria from different taxonomic groups exhibited very low levels of uptake of 2-[U-(14)C]oxoglutarate. Synechococcus sp. strain PCC 7942 was transformed with DNA constructs carrying the Escherichia coli kgtP gene encoding a 2-oxoglutarate permease and a kanamycin resistance gene cassette. The Synechococcus sp. strains bearing the kgtP gene incorporated 2-oxoglutarate into the cells through an active transport process. About 75% of the radioactivity from the 2-[U-(14)C]oxoglutarate taken up that was recovered in soluble metabolites was found as glutamate and glutamine. 2-Oxoglutarate was, however, detrimental to the growth of a Synechococcus sp. strain bearing the kgtP gene.
Collapse
Affiliation(s)
- M F Vázquez-Bermúdez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, E-41092 Seville, Spain
| | | | | |
Collapse
|
14
|
Lee HM, Vázquez-Bermúdez MF, de Marsac NT. The global nitrogen regulator NtcA regulates transcription of the signal transducer PII (GlnB) and influences its phosphorylation level in response to nitrogen and carbon supplies in the Cyanobacterium synechococcus sp. strain PCC 7942. J Bacteriol 1999; 181:2697-702. [PMID: 10217756 PMCID: PMC93707 DOI: 10.1128/jb.181.9.2697-2702.1999] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The PII protein is encoded by a unique glnB gene in Synechococcus sp. strain PCC 7942. Its expression has been analyzed in the wild type and in NtcA-null mutant cells grown under different conditions of nitrogen and carbon supply. RNA-DNA hybridization experiments revealed the presence of one transcript species 680 nucleotides long, whatever the nutrient conditions tested. A second transcript species, 620 nucleotides long, absent in the NtcA null mutant, was observed in wild-type cells that were nitrogen starved for 2 h under both high and low CO2 and in the presence of nitrate under a high CO2 concentration. Primer extension analysis indicated that the two transcript species are generated from two tandem promoters, a sigma70 Escherichia coli-type promoter and an NtcA-dependent promoter, located 120 and 53 nucleotides, respectively, from the glnB initiation codon. The NtcA-dependent promoter is up-regulated under the conditions mentioned above, while the sigma70 E. coli-type promoter displays constitutive levels of transcripts in the NtcA null mutant and slightly different levels in the wild-type cells, depending on the nitrogen and carbon supplies. In general, a good correlation between the amounts of the two transcript species and that of the PII protein was observed, as revealed by immunodetection with specific antibodies. The phosphorylation level of PII in the wild type is inversely correlated with nitrogen availability and directly correlated with higher CO2 concentration. This regulation is correspondingly less stringent in the NtcA null mutant cells. In contrast, the dephosphorylation of PII is NtcA independent.
Collapse
Affiliation(s)
- H M Lee
- Département de Biochimie et Génétique Moléculaire, Unité de Physiologie Microbienne, Institut Pasteur, 75724 Paris Cedex 15, France
| | | | | |
Collapse
|
15
|
Görl M, Sauer J, Baier T, Forchhammer K. Nitrogen-starvation-induced chlorosis in Synechococcus PCC 7942: adaptation to long-term survival. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 9):2449-2458. [PMID: 9782492 DOI: 10.1099/00221287-144-9-2449] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
When deprived of essential nutrients, the non-diazotrophic cyanobacterium Synechococcus sp. strain PCC 7942 undergoes a proteolytic degradation of the phycobiliproteins, its major light-harvesting pigments. This process is known as chlorosis. This paper presents evidence that the degradation of phycobiliproteins is part of an acclimation process in which growing cells differentiate into non-pigmented cells able to endure long periods of starvation. The time course of degradation processes differs for various photosynthetic pigments, for photosystem I and photosystem II activities and is strongly influenced by the illumination and by the experimental conditions of nutrient deprivation. Under standard experimental conditions of combined nitrogen deprivation, three phases of the differentiation process can be defined. The first phase corresponds to the well-known phycobiliprotein degradation, in phase 2 the cells lose chlorophyll a prior to entering phase 3, the fully differentiated state, in which the cells are still able to regenerate pigmentation after the addition of nitrate to the culture. An analysis of the protein synthesis patterns by two-dimensional gel electrophoresis during nitrogen starvation indicates extensive differential gene expression, suggesting the operation of tight regulatory mechanisms.
Collapse
Affiliation(s)
- Margit Görl
- Lehrstuhl für Mikrobiologie der Universität MünchenMaria-Ward-Straße 1a, D-80638 MünchenGermany
| | - Jörg Sauer
- Lehrstuhl für Mikrobiologie der Universität MünchenMaria-Ward-Straße 1a, D-80638 MünchenGermany
| | - Tina Baier
- Lehrstuhl für Mikrobiologie der Universität MünchenMaria-Ward-Straße 1a, D-80638 MünchenGermany
| | - Karl Forchhammer
- Lehrstuhl für Mikrobiologie der Universität MünchenMaria-Ward-Straße 1a, D-80638 MünchenGermany
| |
Collapse
|
16
|
Tapia MI, de Alda JAGO, Llama MJ, Serra JL. Changes in intracellular amino acids and organic acids induced by nitrogen starvation and nitrate or ammonium resupply in the cyanobacterium Phormidium laminosum. PLANTA 1996; 198:526-531. [PMID: 28321662 DOI: 10.1007/bf00262638] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/1995] [Accepted: 08/24/1995] [Indexed: 06/06/2023]
Abstract
In Phormidium laminosum cells, nitrogen starvation caused a decrease in the intracellular levels of all amino acids, except glutamate, and an increase in the total level of the analyzed organic acids. The addition of nitrate or ammonium to N-starved cells resulted in substantial increases in the pool size of most amino acids. Upon addition of ammonium the total level of organic acids diminished, whereas it increased upon addition of nitrate, after a transient decay during the first minutes. Nitrogen resupply stimulated amino acid synthesis, the effect being faster and higher when ammonium was assimilated. The data indicate that nitrate and ammonium assimilation induced an enhancement of carbon flow through the glycolytic and the tricarboxylic-acid pathways to amino acid biosynthesis, with a concurrent decrease in the carbohydrate reserves. The results suggest that the availability of carbon skeletons limited the rate of ammonium assimilation, whereas the availability of reducing equivalents limited the rate of nitrate assimilation.
Collapse
Affiliation(s)
- María I Tapia
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco, Apartado 644, E-48080, Bilbao, Spain
| | - Jesús A G Ochoa de Alda
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco, Apartado 644, E-48080, Bilbao, Spain
| | - María J Llama
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco, Apartado 644, E-48080, Bilbao, Spain
| | - Juan L Serra
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco, Apartado 644, E-48080, Bilbao, Spain.
| |
Collapse
|
17
|
Liotenberg S, Campbell D, Rippka R, Houmard J, de Marsac NT. Effect of the nitrogen source on phycobiliprotein synthesis and cell reserves in a chromatically adapting filamentous cyanobacterium. MICROBIOLOGY (READING, ENGLAND) 1996; 142 ( Pt 3):611-622. [PMID: 8868436 DOI: 10.1099/13500872-142-3-611] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cyanobacteria can utilize nitrate or ammonium as a source of fixed nitrogen for cell growth. In the filamentous Calothrix sp. strain PCC 7601, these two sources of nitrogen differently influenced the phycobiliprotein composition of the phycobilisomes, the major light-harvesting antennae. When compared to nitrate, growth in the presence of ammonium resulted in intracellular steady-state levels 35% lower for phycoerythrin and 46% higher for phycocyanin. Besides these differences in cell pigmentation, a rapid but transient accumulation of cyanophycin granule polypeptide occurred in ammonium-grown cells, while these macromolecules were not detected in cells grown with nitrate. In contrast, glycogen reserves displayed a dynamic pattern of accumulation and disappearance during cell growth which varied only slightly with the nitrogen source. The observed changes in cell pigmentation are reminiscent of the phenomenon of complementary chromatic adaptation, in which green and red wavelengths promote the syntheses of phycoerythrin and phycocyanin-2, respectively. As in complementary chromatic adaptation, the regulation of synthesis of phycoerythrin and phycocyanin-2 by the nitrogen source occurred mainly at the mRNA level. Moreover, the transcriptional start sites for the expression of the cpeBA and the cpc2 operons, which respectively encode the two subunits of phycoerythrin and phycocyanin-2, were the same in cells grown in nitrate or ammonium, and identical to those in green- and red-light-grown cells. The results of this study suggest that acclimation to the spectral light quality and to the nitrogen source share some common regulatory elements.
Collapse
Affiliation(s)
- Sylviane Liotenberg
- Unité de Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cédex 15, France
| | - Douglas Campbell
- Unité de Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cédex 15, France
| | - Rosmarie Rippka
- Unité de Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cédex 15, France
| | - Jean Houmard
- Unité de Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cédex 15, France
| | - Nicole Tandeau de Marsac
- Unité de Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cédex 15, France
| |
Collapse
|
18
|
Tapia MI, Ochoa de Alda JAG, Llama MJ, Serra JL. Determination of 2-Oxoglutarate in the Presence of Citrate and/or Isocitrate After Ion-Exclusion High-Performance Liquid Chromatography. ANAL LETT 1995. [DOI: 10.1080/00032719508000017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
19
|
Forchhammer K, Tandeau de Marsac N. Functional analysis of the phosphoprotein PII (glnB gene product) in the cyanobacterium Synechococcus sp. strain PCC 7942. J Bacteriol 1995; 177:2033-40. [PMID: 7721695 PMCID: PMC176846 DOI: 10.1128/jb.177.8.2033-2040.1995] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The PII protein (glnB gene product) in the cyanobacterium Synechococcus sp. strain PCC 7942 signals the cellular N status by being phosphorylated or dephosphorylated at a seryl residue. Here we show that the PII-modifying system responds to the activity of ammonium assimilation via the glutamine synthase-glutamate synthase pathway and to the state of CO2 fixation. To identify possible functions of PII in this microorganism, a PII-deficient mutant was created and its general phenotype was characterized. The analysis shows that the PII protein interferes with the regulation of enzymes required for nitrogen assimilation, although ammonium repression is still detectable in the PII-deficient mutant. We suggest that the phosphorylation and dephosphorylation of PII are part of a complex signal transduction network involved in global nitrogen control in cyanobacteria. In this regulatory process, PII might be involved in mediating the tight coordination between carbon and nitrogen assimilation.
Collapse
Affiliation(s)
- K Forchhammer
- Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France
| | | |
Collapse
|
20
|
Forchhammer K, Tandeau de Marsac N. The PII protein in the cyanobacterium Synechococcus sp. strain PCC 7942 is modified by serine phosphorylation and signals the cellular N-status. J Bacteriol 1994; 176:84-91. [PMID: 8282715 PMCID: PMC205017 DOI: 10.1128/jb.176.1.84-91.1994] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The glnB gene product (PII protein) from Synechococcus sp. has previously been identified among 32P-labeled proteins, and its modification state has been observed to depend on both the nitrogen source and the spectral light quality (N. F. Tsinoremas, A. M. Castets, M. A. Harrison, J. F. Allen, and N. Tandeau de Marsac, Proc. Natl. Acad. Sci. USA 88:4565-4569, 1991). As shown in this study, modification of the PII protein primarily responds to the N-status of the cell, and its light-dependent variations are are mediated through nitrate metabolism. Modification of the PII protein results in the appearance of three isomeric forms with increasing negative charge. Unlike its homolog counterparts characterized so far, PII in Synechococcus sp. is modified by phosphorylation on a serine residue, which represents a unique kind of protein modification in bacterial nitrogen signalling pathways.
Collapse
Affiliation(s)
- K Forchhammer
- Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France
| | | |
Collapse
|