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Klińska-Bąchor S, Demski K, Gong Y, Banaś A. Metabolic engineering of omega-3 long chain polyunsaturated fatty acids in plants using different ∆6- and ∆5-desaturases co-expressed with LPCAT from the marine diatom Phaeodactylum tricornutum. Sci Rep 2024; 14:9512. [PMID: 38664593 PMCID: PMC11045822 DOI: 10.1038/s41598-024-60141-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
Continuous research on obtaining an even more efficient production of very long-chain polyunsaturated fatty acids (VLC-PUFAs) in plants remains one of the main challenges of scientists working on plant lipids. Since crops are not able to produce these fatty acids due to the lack of necessary enzymes, genes encoding them must be introduced exogenously from native organisms producing VLC-PUFAs. In this study we reported, in tobacco leaves, the characterization of three distinct ∆6-desaturases from diatom Phaeodactylum tricornutum, fungi Rhizopus stolonifer and microalge Osterococcus tauri and two different ∆5-desaturases from P. tricornutum and single-celled saprotrophic eukaryotes Thraustochytrium sp. The in planta agroinfiltration of essential ∆6-desaturases, ∆6-elongases and ∆5-desaturases allowed for successful introduction of eicosapentaenoic acid (20:5∆5,8,11,14,17) biosynthesis pathway. However, despite the desired, targeted production of ω3-fatty acids we detected the presence of ω6-fatty acids, indicating and confirming previous results that all tested desaturases are not specifically restricted to neither ω3- nor ω6-pathway. Nevertheless, the additional co-expression of acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) from Phaeodactylum tricornutum boosted the proportion of ω3-fatty acids in newly synthesized fatty acid pools. For the most promising genes combinations the EPA content reached at maximum 1.4% of total lipid content and 4.5% of all fatty acids accumulated in the TAG pool. Our results for the first time describe the role of LPCAT enzyme and its effectiveness in alleviating a bottleneck called 'substrate dichotomy' for improving the transgenic production of VLC-PUFAs in plants.
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Affiliation(s)
- Sylwia Klińska-Bąchor
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, ul Abrahama 58, 80-307, Gdańsk, Poland.
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 190, 23422, Lomma, Sweden.
| | - Kamil Demski
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 190, 23422, Lomma, Sweden
| | - Yangmin Gong
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, ul Abrahama 58, 80-307, Gdańsk, Poland
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Klińska-Bąchor S, Demski K, Gong Y, Banaś A. Biochemical characterization of acyl-CoA:diacylglycerol acyltransferase2 from the diatom Phaeodactylum tricornutum and its potential effect on LC-PUFAs biosynthesis in planta. BMC Plant Biol 2024; 24:309. [PMID: 38649801 PMCID: PMC11036593 DOI: 10.1186/s12870-024-05014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/12/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), belonging to ω-3 long-chain polyunsaturated fatty acids (ω3-LC-PUFAs), are essential components of human diet. They are mainly supplemented by marine fish consumption, although their native producers are oleaginous microalgae. Currently, increasing demand for fish oils is insufficient to meet the entire global needs, which puts pressure on searching for the alternative solutions. One possibility may be metabolic engineering of plants with an introduced enzymatic pathway producing ω3-LC-PUFAs. RESULT In this study we focused on the acyl-CoA:diacylglycerol acyltransferase2b (PtDGAT2b) from the diatom Phaeodactylum tricornutum, an enzyme responsible for triacylglycerol (TAG) biosynthesis via acyl-CoA-dependent pathway. Gene encoding PtDGAT2b, incorporated into TAG-deficient yeast strain H1246, was used to confirm its activity and conduct biochemical characterization. PtDGAT2b exhibited a broad acyl-CoA preference with both di-16:0-DAG and di-18:1-DAG, whereas di-18:1-DAG was favored. The highest preference for acyl donors was observed for 16:1-, 10:0- and 12:0-CoA. PtDGAT2b also very efficiently utilized CoA-conjugated ω-3 LC-PUFAs (stearidonic acid, eicosatetraenoic acid and EPA). Additionally, verification of the potential role of PtDGAT2b in planta, through its transient expression in tobacco leaves, indicated increased TAG production with its relative amount increasing to 8%. Its co-expression with the gene combinations aimed at EPA biosynthesis led to, beside elevated TAG accumulation, efficient accumulation of EPA which constituted even 25.1% of synthesized non-native fatty acids (9.2% of all fatty acids in TAG pool). CONCLUSIONS This set of experiments provides a comprehensive biochemical characterization of DGAT enzyme from marine microalgae. Additionally, this study elucidates that PtDGAT2b can be used successfully in metabolic engineering of plants designed to obtain a boosted TAG level, enriched not only in ω-3 LC-PUFAs but also in medium-chain and ω-7 fatty acids.
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Affiliation(s)
- Sylwia Klińska-Bąchor
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland.
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.
| | - Kamil Demski
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Yangmin Gong
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
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Saft M, Schneider L, Ho CC, Maiterth E, Menke J, Sendker F, Steinchen W, Essen LO. One More for Light-triggered Conformational Changes in Cryptochromes: CryP from Phaeodactylum tricornutum. J Mol Biol 2024; 436:168408. [PMID: 38123123 DOI: 10.1016/j.jmb.2023.168408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 12/01/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Cryptochromes are a ubiquitously occurring class of photoreceptors. Together with photolyases, they form the Photolyase Cryptochrome Superfamily (PCSf) by sharing a common protein architecture and binding mode of the FAD chromophore. Despite these similarities, PCSf members exert different functions. Photolyases repair UV-induced DNA damage by photocatalytically driven electron transfer between FADH¯ and the DNA lesion, whereas cryptochromes are light-dependent signaling molecules and trigger various biological processes by photoconversion of their FAD redox and charge states. Given that most cryptochromes possess a C-terminal extension (CTE) of varying length, the functions of their CTE have not yet been fully elucidated and are hence highly debated. In this study, the role of the CTE was investigated for a novel subclass of the PCSf, the CryP-like cryptochromes, by hydrogen/deuterium exchange and mass-spectrometric analysis. Striking differences in the relative deuterium uptake were observed in different redox states of CryP from the diatom Phaeodactylum tricornutum. Based on these measurements we propose a model for light-triggered conformational changes in CryP-like cryptochromes that differs from other known cryptochrome families like the insect or plant cryptochromes.
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Affiliation(s)
- Martin Saft
- Department of Chemistry, Philipps University Marburg, 35032 Marburg, Germany
| | - Leonie Schneider
- Department of Chemistry, Philipps University Marburg, 35032 Marburg, Germany
| | - Chun-Chih Ho
- Department of Chemistry, Philipps University Marburg, 35032 Marburg, Germany
| | - Elias Maiterth
- Department of Chemistry, Philipps University Marburg, 35032 Marburg, Germany
| | - Josephine Menke
- Department of Chemistry, Philipps University Marburg, 35032 Marburg, Germany
| | - Franziska Sendker
- Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Wieland Steinchen
- Center of Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35032 Marburg, Germany
| | - Lars-Oliver Essen
- Department of Chemistry, Philipps University Marburg, 35032 Marburg, Germany.
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Jiang Y, Cao T, Yang Y, Zhang H, Zhang J, Li X. A chlorophyll c synthase widely co-opted by phytoplankton. Science 2023; 382:92-98. [PMID: 37797009 DOI: 10.1126/science.adg7921] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/30/2023] [Indexed: 10/07/2023]
Abstract
Marine and terrestrial photosynthesis exhibit a schism in the accessory chlorophyll (Chl) that complements the function of Chl a: Chl b for green plants versus Chl c for most eukaryotic phytoplankton. The enzymes that mediate Chl c biosynthesis have long remained elusive. In this work, we identified the CHLC dioxygenase (Phatr3_J43737) from the marine diatom Phaeodactylum tricornutum as the Chl c synthase. The chlc mutants lacked Chl c, instead accumulating its precursors, and exhibited growth defects. In vitro, recombinant CHLC protein converted these precursors into Chl c, thereby confirming its identity. Phylogenetic evidence demonstrates conserved use of CHLC across phyla but also the existence of distinct Chl c synthases in different algal groups. Our study addresses a long-outstanding question with implications for both contemporary and ancient marine photosynthesis.
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Affiliation(s)
- Yanyou Jiang
- Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Tianjun Cao
- Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Yuqing Yang
- Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Huan Zhang
- Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
| | - Jingyu Zhang
- Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Xiaobo Li
- Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China
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Połońska A, Jasieniecka-Gazarkiewicz K, You L, Hao X, Klińska S, Gong Y, Banaś A. Diatoms and Plants Acyl-CoA:lysophosphatidylcholine Acyltransferases (LPCATs) Exhibit Diverse Substrate Specificity and Biochemical Properties. Int J Mol Sci 2021; 22:ijms22169056. [PMID: 34445762 PMCID: PMC8396554 DOI: 10.3390/ijms22169056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/20/2021] [Accepted: 08/20/2021] [Indexed: 11/16/2022] Open
Abstract
The search of the Phaeodactylum tricornutum genome database revealed the existence of six genes potentially encoding lysophospholipid acyltransferases. One of these genes, Phatr3_J20460, after introduction to yeast ale1 mutant disrupted in the LPCAT gene, produced a very active acyl-CoA:lysophosphatidylcholine (LPCAT) enzyme. Using in vitro assays applying different radioactive and non-radioactive substrates and microsomal fractions from such yeast, we have characterized the biochemical properties and substrate specificities of this PtLPCAT1. We have found that the substrate specificity of this enzyme indicates that it can completely supply phosphatidylcholine (PC) with all fatty acids connected with a biosynthetic pathway of very long-chain polyunsaturated fatty acids (VLC-PUFAs) used further for the desaturation process. Additionally, we have shown that biochemical properties of the PtLPCAT1 in comparison to plant LPCATs are in some cases similar (such as the dependency of its activity on pH value), differ moderately (such as in response to temperature changes), or express completely different properties (such as in reaction to calcium and magnesium ions or toward some acyl-CoA with 20C polyunsaturated fatty acids). Moreover, the obtained results suggest that cloned “Phatr3_J20460” gene can be useful in oilseeds plant engineering toward efficient production of VLC-PUFA as LPCAT it encodes can (contrary to plant LPCATs) introduce 20:4-CoA (n-3) to PC for further desaturation to 20:5 (EPA, eicosapentaenoic acid).
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Affiliation(s)
- Ada Połońska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdańsk, 80-307 Gdansk, Poland; (K.J.-G.); (S.K.)
- Correspondence: (A.P.); (A.B.)
| | - Katarzyna Jasieniecka-Gazarkiewicz
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdańsk, 80-307 Gdansk, Poland; (K.J.-G.); (S.K.)
| | - Lingjie You
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China; (L.Y.); (X.H.); (Y.G.)
| | - Xiahui Hao
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China; (L.Y.); (X.H.); (Y.G.)
| | - Sylwia Klińska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdańsk, 80-307 Gdansk, Poland; (K.J.-G.); (S.K.)
| | - Yangmin Gong
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China; (L.Y.); (X.H.); (Y.G.)
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdańsk, 80-307 Gdansk, Poland; (K.J.-G.); (S.K.)
- Correspondence: (A.P.); (A.B.)
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Jensen EL, Receveur-Brechot V, Hachemane M, Wils L, Barbier P, Parsiegla G, Gontero B, Launay H. Structural Contour Map of the Iota Carbonic Anhydrase from the Diatom Thalassiosira pseudonana Using a Multiprong Approach. Int J Mol Sci 2021; 22:ijms22168723. [PMID: 34445427 PMCID: PMC8395977 DOI: 10.3390/ijms22168723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 02/07/2023] Open
Abstract
Carbonic anhydrases (CAs) are a family of ubiquitous enzymes that catalyze the interconversion of CO2 and HCO3−. The “iota” class (ι-CA) was first found in the marine diatom Thalassiosira pseudonana (tpι-CA) and is widespread among photosynthetic microalgae and prokaryotes. The ι-CA has a domain COG4875 (or COG4337) that can be repeated from one to several times and resembles a calcium–calmodulin protein kinase II association domain (CaMKII-AD). The crystal structure of this domain in the ι-CA from a cyanobacterium and a chlorarachniophyte has been recently determined. However, the three-dimensional organization of the four domain-containing tpι-CA is unknown. Using biophysical techniques and 3-D modeling, we show that the homotetrameric tpι-CA in solution has a flat “drone-like” shape with a core formed by the association of the first two domains of each monomer, and four protruding arms formed by domains 3 and 4. We also observe that the short linker between domains 3 and 4 in each monomer confers high flexibility, allowing for different conformations to be adopted. We propose the possible 3-D structure of a truncated tpι-CA containing fewer domain repeats using experimental data and discuss the implications of this atypical shape on the activity and metal coordination of the ι-CA.
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Affiliation(s)
- Erik L. Jensen
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
| | - Véronique Receveur-Brechot
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
| | - Mohand Hachemane
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
| | - Laura Wils
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
| | - Pascale Barbier
- Aix Marseille Univ, CNRS, INP, Inst Neurophysiopathol, 13 402 Marseille, France;
| | - Goetz Parsiegla
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
| | - Brigitte Gontero
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
- Correspondence: (B.G.); (H.L.)
| | - Hélène Launay
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR 3479, 31 Chemin J. Aiguier, CEDEX 20, 13 402 Marseille, France; (E.L.J.); (V.R.-B.); (M.H.); (L.W.); (G.P.)
- Correspondence: (B.G.); (H.L.)
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Feijão E, Franzitta M, Cabrita MT, Caçador I, Duarte B, Gameiro C, Matos AR. Marine heat waves alter gene expression of key enzymes of membrane and storage lipids metabolism in Phaeodactylum tricornutum. Plant Physiol Biochem 2020; 156:357-368. [PMID: 33002714 DOI: 10.1016/j.plaphy.2020.09.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
Across the globe, heat waves are getting more intense and frequent. Diatoms are a major group of microalgae at the base of the marine food webs and an important source of long chain polyunsaturated fatty acids that are transferred through the food web. The present study investigates the possible impacts of temperature increase on lipid classes and expression of genes encoding enzymes related to lipid metabolism in Phaeodactylum tricornutum. The heat wave exposure caused an increase in the relative amounts of plastidial lipids such as the glycolipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and sulphoquinovosyldiacylglycerol (SQDG) in parallel with a decrease in the neutral lipid fraction, which includes triacylglycerols. In agreement, gene expression analyses revealed an up-regulation of a gene encoding one MGDG synthase and down-regulation of a diacylglycerol acyltransferase (DGAT), a key enzyme in triacylglycerol synthesis. Our results show that heat waves not only negatively impact the abundance of unsaturated fatty acids such as eicosapentaenoic acid (20:5n-3, EPA) and hexadecatrienoic acid (16:3n-4) as observed by the decrease in their relative abundance in MGDG and neutral lipids, respectively, but also induce changes in the relative amounts of the diverse membrane lipids as well as the proportion of membrane/storage lipids. The expression study of key genes indicates that some of the aforementioned alterations are regulated at the transcription level whereas others appear to be post-transcriptional. The changes observed in plastidial lipids are related to negative impacts on the photosynthesis.
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Affiliation(s)
- Eduardo Feijão
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016, Lisboa, Portugal; MARE - Marine and Environmental Sciences Centre, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Marco Franzitta
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016, Lisboa, Portugal
| | - Maria Teresa Cabrita
- Centro de Estudos Geográficos (CEG), Instituto de Geografia e Ordenamento do Território (IGOT), Universidade de Lisboa, Rua Branca Edmée Marques, 1600-276, Lisboa, Portugal
| | - Isabel Caçador
- MARE - Marine and Environmental Sciences Centre, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
| | - Bernardo Duarte
- MARE - Marine and Environmental Sciences Centre, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
| | - Carla Gameiro
- IPMA, Instituto Português do Mar e Atmosfera, Div-RP - Divisão de Modelação e Gestão de Recursos de Pesca, 1495-165, Algés, Portugal
| | - Ana Rita Matos
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016, Lisboa, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
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Huang SP, Zhou LC, Wen B, Wang P, Zhu GP. Biochemical Characterization and Crystal Structure of a Novel NAD +-Dependent Isocitrate Dehydrogenase from Phaeodactylum tricornutum. Int J Mol Sci 2020; 21:ijms21165915. [PMID: 32824636 PMCID: PMC7460673 DOI: 10.3390/ijms21165915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022] Open
Abstract
The marine diatom Phaeodactylum tricornutum originated from a series of secondary symbiotic events and has been used as a model organism for studying diatom biology. A novel type II homodimeric isocitrate dehydrogenase from P. tricornutum (PtIDH1) was expressed, purified, and identified in detail through enzymatic characterization. Kinetic analysis showed that PtIDH1 is NAD+-dependent and has no detectable activity with NADP+. The catalytic efficiency of PtIDH1 for NAD+ is 0.16 μM-1·s-1 and 0.09 μM-1·s-1 in the presence of Mn2+ and Mg2+, respectively. Unlike other bacterial homodimeric NAD-IDHs, PtIDH1 activity was allosterically regulated by the isocitrate. Furthermore, the dimeric structure of PtIDH1 was determined at 2.8 Å resolution, and each subunit was resolved into four domains, similar to the eukaryotic homodimeric NADP-IDH in the type II subfamily. Interestingly, a unique and novel C-terminal EF-hand domain was first defined in PtIDH1. Deletion of this domain disrupted the intact dimeric structure and activity. Mutation of the four Ca2+-binding sites in the EF-hand significantly reduced the calcium tolerance of PtIDH1. Thus, we suggest that the EF-hand domain could be involved in the dimerization and Ca2+-coordination of PtIDH1. The current report, on the first structure of type II eukaryotic NAD-IDH, provides new information for further investigation of the evolution of the IDH family.
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Li K, Li M, He Y, Gu X, Pang K, Ma Y, Lu D. Effects of pH and nitrogen form on Nitzschia closterium growth by linking dynamic with enzyme activity. Chemosphere 2020; 249:126154. [PMID: 32062215 DOI: 10.1016/j.chemosphere.2020.126154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/16/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
In this study, Nitzschia closterium was incubated in seawater at different pH values (8.10, 7.71, and 7.45) and using different nitrogen forms (NO3-N and NH4-N) in the laboratory. The results showed that the growth of N. closterium was inhibited by ocean acidification, with individuals under lower pH levels showing lower growth rates and lower nitrogen uptake rates for both nitrogen forms. The Vmax/Ks ratio decreased with decreasing pH, indicating the inhibition of nitrogen uptake, whereas the ratios for NH4-N cultures were higher than those for NO3-N cultures, implying the highly competitive position of NH4-N. Acidification might induce reactive oxygen species based on the result that the maximum enzyme activities of SuperOxide Dismutase (SOD) and CATalase (CAT) increased under lower pH levels. The SOD and CAT activities for the NO3-N cultures were higher than those for NH4-N cultures at the low pH level, indicating that acidification might cause more oxidative stress for NO3-N cultures than for NH4-N cultures. Thus, ocean acidification might have a more detrimental effect on the growth of N. closterium under NO3-N conditions than NH4-N conditions, with a lower ratio (γ) of the maximum growth rate to the maximum nutrient uptake rate, and a drop in nitrate reductase activity under lower pH levels.
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Affiliation(s)
- Keqiang Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
| | - Min Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Yunfeng He
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Xingyan Gu
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Kai Pang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Yunpeng Ma
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China; Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Dongliang Lu
- Guangxi Key Laboratory of Marine Disaster in the Beibu Gulf, Beibu Gulf University, Qinzhou, 535011, China
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10
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Olchawa-Pajor M, Bojko M, Strzałka W, Strzałka K, Latowski D. Violaxanthin conversion by recombinant diatom and plant de-epoxidases, expressed in Escherichia coli - comparative analysis. Acta Biochim Pol 2019; 66:249-255. [PMID: 31279328 DOI: 10.18388/abp.2019_2831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/01/2019] [Indexed: 11/10/2022]
Abstract
The purpose of this research was to obtain recombinant violaxanthin de-epoxidases (VDEs) from two species. The first one was VDE of Arabidopsis thaliana (L.) Heynh. (WT Columbia strain) (AtVDE) which in vivo catalyzes conversion of violaxanthin (Vx) to zeaxanthin (Zx) via anteraxanthin (Ax). The second one was VDE of Phaeodactylum tricornutum Bohlin, 1897 (CCAP 1055/1 strain) (PtVDE) which is responsible for de-epoxidation of diadinoxanthin (Ddx) to diatoxanthin (Dtx). As the first step of our experiments, open reading frames coding for studied enzymes were amplified and subsequently cloned into pET-15b plasmid. For recombinant proteins production Escherichia coli Origami b strain was used. The molecular weight of the produced enzymes were estimated approximately at 45kDa and 50kDa for AtVDE and PtVDE, respectively. Both enzymes, purified under native conditions by immobilized metal affinity chromatography, displayed comparable activity in assay mixture and converted up to 90% Vx in 10 min in two steps enzymatic de-epoxidation, irrespective of enzyme origin. No statistically significant differences were observed when kinetics of the reactions catalyzed by these enzymes were compared. Putative role of selected amino-acid residues of AtVDE and PtVDE was also considered. The significance of the first time obtained recombinant PtVDE as a useful tool in various comparative investigations of de-epoxidation reactions in main types of xanthophyll cycles existing in nature are also indicated.
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Affiliation(s)
- Monika Olchawa-Pajor
- Department of Environmental Protection, Institute of Mathematical and Natural Sciences, State Higher Vocational School in Tarnow, Poland
| | - Monika Bojko
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Wojciech Strzałka
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Kazimierz Strzałka
- 1Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland; 2Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Dariusz Latowski
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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11
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Taparia Y, Zarka A, Leu S, Zarivach R, Boussiba S, Khozin-Goldberg I. A novel endogenous selection marker for the diatom Phaeodactylum tricornutum based on a unique mutation in phytoene desaturase 1. Sci Rep 2019; 9:8217. [PMID: 31160749 PMCID: PMC6546710 DOI: 10.1038/s41598-019-44710-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/21/2019] [Indexed: 01/10/2023] Open
Abstract
Phaeodactylum tricornutum is a well-developed model diatom for both marine ecology and microalgal biotechnology, which has been enabled by the sequenced genome and the availability of gene delivery tools, such as biolistic transformation and E. coli-mediated conjugation. Till now, these tools have mainly relied on two selectable markers of bacterial origin which confer resistance to antibiotics Zeocin and nourseothricin. An alternative cost-effective and preferably endogenous selectable marker would facilitate gene stacking efforts through successive transformation or conjugation. We performed UV-mutagenesis of P. tricornutum to obtain mutations in the phytoene desaturase (PDS) gene, conferring resistance to the bleaching herbicide norflurazon. Two mutants displaying high tolerance to norflurazon and carrying unique mutations in PtPDS1 (PHATRDRAFT_45735) were selected. These mutants revealed novel point mutations at a conserved residue Gly290 to Ser/Arg. Homology-based structural modeling of mutated PDS1, over a resolved crystallographic model of rice PDS1 complexed with norflurazon, suggests steric hindrance by bulkier residue substitution may confer herbicide resistance. We report the characterization of PtPDS1 mutants and the development of the first endogenous selectable marker in diatoms suitable for industrial strain development, with the added benefit of biocontainment. The plasmid carrying the mutated PDS1 as a selection marker and eGFP as a reporter was created. An optimized biolistic transformation system is reported which allowed the isolation of positive transgenic events at the rate of 96.7%. Additionally, the ease of in vivo UV-mutagenesis may be employed as a strategy to create PDS-norflurazon-based selectable markers for other diatoms.
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Affiliation(s)
- Yogesh Taparia
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture & Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Aliza Zarka
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture & Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Stefan Leu
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture & Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Raz Zarivach
- Department of Life Sciences, Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Sammy Boussiba
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture & Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture & Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel.
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12
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Wang X, Miao J, Pan L, Li Y, Lin Y, Wu J. Toxicity effects of p-choroaniline on the growth, photosynthesis, respiration capacity and antioxidant enzyme activities of a diatom, Phaeodactylum tricornutu. Ecotoxicol Environ Saf 2019; 169:654-661. [PMID: 30496998 DOI: 10.1016/j.ecoenv.2018.11.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
The environmental risk issues of p-choroaniline have been concerned by the widespread application and transportation of this important chemical intermediate. The information about the toxicity of p-chloroaniline was mainly concentrated on freshwater organisms while the current knowledge on marine organisms was scarce yet. In this study, acute toxicity and toxic physiology characteristic of p-chloroaniline to Phaeodactylum tricornutum (P. tricornutum) were first determined. In the acute experiments, the effect of the p-choroaniline to P. tricornutum showed time- and dose-dependent response, which the half maximum effective concentration (EC50) at 24 h, 48 h and 96 h was 35.35, 20.10 and 10.00 mgL-1, respectively. Toxic physiology assays in P. tricornutum indicated that the p-choroaniline induced significant changes of photosynthetic pigments (Chl-a, Chl-b, Caro, Chl-a/b and Chl-(a+b)/Caro), Chlorophyll fluorescence parameters (Fv/Fm, ETR, qP and NPQ), rates of photosynthetic O2 release and respiration O2 consumption, and antioxidant enzyme activities (SOD, CAT). The obvious decrease of Fv/Fm, ETR and chl-a in low p-choroaniline treatments (≤ 5.00 mgL-1) compared with the control could be observed, which implied that these parameters could be taken as sensitive indicators for the environmental assessment. Meanwhile, the activities of SOD and CAT significant increase in p-choroaniline stress after 24 h and the extent of the increase has fallen after 96 h. These toxicity data obtained here might provide available basic data for the ecological risk assessment of p-choroaniline pollution.
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Affiliation(s)
- Xiufen Wang
- The key laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, Shangdong p, China
| | - Jingjing Miao
- The key laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, Shangdong p, China
| | - Luqing Pan
- The key laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, Shangdong p, China
| | - Yun Li
- The key laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, Shangdong p, China.
| | - Yufei Lin
- National Marine Hazard Mitigation Service, State Ocean Administration, People's Republic of China, Beijing 100194, China
| | - Jiangyue Wu
- National Marine Hazard Mitigation Service, State Ocean Administration, People's Republic of China, Beijing 100194, China
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13
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Murik O, Tirichine L, Prihoda J, Thomas Y, Araújo WL, Allen AE, Fernie AR, Bowler C. Downregulation of mitochondrial alternative oxidase affects chloroplast function, redox status and stress response in a marine diatom. New Phytol 2019; 221:1303-1316. [PMID: 30216452 DOI: 10.1111/nph.15479] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/03/2018] [Indexed: 05/20/2023]
Abstract
Diatom dominance in contemporary aquatic environments indicates that they have developed unique and effective mechanisms to cope with the rapid and considerable fluctuations that characterize these environments. In view of their evolutionary history from a secondary endosymbiosis, inter-organellar regulation of biochemical activities may be of particular relevance. Diatom mitochondrial alternative oxidase (AOX) is believed to play a significant role in supplying chloroplasts with ATP produced in the mitochondria. Using the model diatom Phaeodactylum tricornutum we generated AOX knockdown lines, and followed sensitivity to stressors, photosynthesis and transcriptome and metabolome profiles of wild-type and knockdown lines. We show here that expression of the AOX gene is upregulated by various stresses including H2 O2 , heat, high light illumination, and iron or nitrogen limitation. AOX knockdown results in hypersensitivity to stress. Knockdown lines also show significantly reduced photosynthetic rates and their chloroplasts are more oxidized. Comparisons of transcriptome and metabolome profiles suggest a strong impact of AOX activity on gene expression, which is carried through to the level of the metabolome. Our data provide evidence for the involvement of mitochondrial AOX in processes central to the cell biology of diatoms, revealing that cross-talk between mitochondria and chloroplasts is crucial for maintaining sensitivity to changing environments.
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Affiliation(s)
- Omer Murik
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Leila Tirichine
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Judit Prihoda
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Yann Thomas
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Wagner L Araújo
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrew E Allen
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, CA, 92037, USA
- Integrative Oceanography Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, 92037, USA
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Chris Bowler
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
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14
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Bua S, Bozdag M, Del Prete S, Carta F, Donald WA, Capasso C, Supuran CT. Mono- and di-thiocarbamate inhibition studies of the δ-carbonic anhydrase TweCAδ from the marine diatom Thalassiosira weissflogii. J Enzyme Inhib Med Chem 2018; 33:707-713. [PMID: 29577755 PMCID: PMC6010021 DOI: 10.1080/14756366.2018.1450400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 11/08/2022] Open
Abstract
The inhibition of the δ-class carbonic anhydrase (CAs, EC 4.2.1.1) from the diatom Thalassiosira weissflogii, TweCAδ, was investigated using a panel of 36 mono- and di-thiocarbamates chemotypes that have recently been shown to inhibit mammalian and pathogenic CAs belonging to the α- and β-classes. TweCAδ was not significantly inhibited by most of such compounds (KI values above 20 µM). However, some aliphatic, heterocyclic, and aromatic mono and di-thiocarbamates inhibited TweCAδ in the low micromolar range. For some compounds incorporating the piperazine ring, TweCAδ was effectively inhibited (KIs from 129 to 791 nM). The most effective inhibitors identified in this study were 3,4-dimethoxyphenyl-ethyl-mono-thiocarbamate (KI of 67.7 nM) and the R-enantiomer of the nipecotic acid di-thiocarbamate (KI of 93.6 nM). Given that the activity and inhibition of this class of enzyme have received limited attention until now, this study provides new molecular probes and information for investigating the role of δ-CAs in the carbon fixation processes in diatoms, which are responsible for significant amounts of CO2 taken from the atmosphere by these marine organisms.
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Affiliation(s)
- Silvia Bua
- Neurofarba Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
| | - Murat Bozdag
- Department of Chemistry, Università degli Studi di Firenze, Florence, Italy
| | - Sonia Del Prete
- Neurofarba Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
- CNR, Istituto di Bioscienze e Biorisorse, Napoli, Italy
| | - Fabrizio Carta
- Neurofarba Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
| | - William A. Donald
- School of Chemistry, University of New South Wales, Sydney, Australia
| | | | - Claudiu T. Supuran
- Neurofarba Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
- School of Chemistry, University of New South Wales, Sydney, Australia
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15
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Berrino E, Bozdag M, Del Prete S, Alasmary FAS, Alqahtani LS, AlOthman Z, Capasso C, Supuran CT. Inhibition of α-, β-, γ-, and δ-carbonic anhydrases from bacteria and diatoms with N'-aryl-N-hydroxy-ureas. J Enzyme Inhib Med Chem 2018; 33:1194-1198. [PMID: 30044657 PMCID: PMC6060382 DOI: 10.1080/14756366.2018.1490733] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/13/2018] [Accepted: 06/13/2018] [Indexed: 11/09/2022] Open
Abstract
The inhibition of α-, β-, γ-, and δ-class carbonic anhydrases (CAs, EC 4.2.1.1) from bacteria (Vibrio cholerae and Porphyromonas gingivalis) and diatoms (Thalassiosira weissflogii) with a panel of N'-aryl-N-hydroxy-ureas is reported. The α-/β-CAs from V. cholerae (VchCAα and VchCAβ) were effectively inhibited by some of these derivatives, with KIs in the range of 97.5 nM - 7.26 µM and 52.5 nM - 1.81 µM, respectively, whereas the γ-class enzyme VchCAγ was less sensitive to inhibition (KIs of 4.75 - 8.87 µM). The β-CA from the pathogenic bacterium Porphyromonas gingivalis (PgiCAβ) was not inhibited by these compounds (KIs > 10 µM) whereas the corresponding γ-class enzyme (PgiCAγ) was effectively inhibited (KIs of 59.8 nM - 6.42 µM). The δ-CA from the diatom Thalassiosira weissflogii (TweCAδ) showed effective inhibition with these derivatives (KIs of 33.3 nM - 8.74 µM). As most of these N-hydroxyureas are also ineffective as inhibitors of the human (h) widespread isoforms hCA I and II (KIs > 10 µM), this class of derivatives may lead to the development of CA inhibitors selective for bacterial/diatom enzymes over their human counterparts and thus to anti-infectives or agents with environmental applications.
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Affiliation(s)
- Emanuela Berrino
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
| | - Murat Bozdag
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
| | - Sonia Del Prete
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
- CNR, Istituto di Bioscienze e Biorisorse, Napoli, Italy
| | - Fatmah A. S. Alasmary
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Linah S. Alqahtani
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
- Department of Chemistry, King Faisal University, Alahsa, Saudi Arabia
| | - Zeid AlOthman
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | | | - Claudiu T. Supuran
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
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16
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Li DW, Xie WH, Hao TB, Cai JX, Zhou TB, Balamurugan S, Yang WD, Liu JS, Li HY. Constitutive and Chloroplast Targeted Expression of Acetyl-CoA Carboxylase in Oleaginous Microalgae Elevates Fatty Acid Biosynthesis. Mar Biotechnol (NY) 2018; 20:566-572. [PMID: 29931608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Photosynthetic microalgae are of burgeoning interest in the generation of commercial bioproducts. Microalgae accumulate high lipid content under adverse conditions, which in turn compromise their growth and hinder their commercial potential. Hence, it is necessary to engineer microalgae to mitigate elevated lipid accumulation and biomass. In this study, we identified acetyl-CoA carboxylase (ACCase) in oleaginous microalga Phaeodactylum tricornutum (PtACC2) and expressed constitutively in the chloroplast to demonstrate the potential of chloroplast engineering. Molecular characterization of transplastomic microalgae revealed that PtACC2 was integrated, transcribed and expressed successfully, and localized in the chloroplast. Enzymatic activity of ACCase was elevated by 3.3-fold, and the relative neutral lipid content increased substantially by 1.77-fold, and lipid content reached up to 40.8% of dry weight. Accordingly, the number and size of oil bodies markedly increased. Fatty acid profiling showed that the content of monounsaturated fatty acids increased, while polyunsaturated fatty acids decreased. This method provides a valuable genetic engineering toolbox for microalgal bioreactors with industrial significance.
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Affiliation(s)
- Da-Wei Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Wei-Hong Xie
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Ting-Bin Hao
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Jia-Xi Cai
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Tian-Bao Zhou
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Srinivasan Balamurugan
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China
| | - Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China.
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17
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Ewe D, Tachibana M, Kikutani S, Gruber A, Río Bártulos C, Konert G, Kaplan A, Matsuda Y, Kroth PG. The intracellular distribution of inorganic carbon fixing enzymes does not support the presence of a C4 pathway in the diatom Phaeodactylum tricornutum. Photosynth Res 2018; 137:263-280. [PMID: 29572588 DOI: 10.1007/s11120-018-0500-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/18/2018] [Indexed: 05/20/2023]
Abstract
Diatoms are unicellular algae and important primary producers. The process of carbon fixation in diatoms is very efficient even though the availability of dissolved CO2 in sea water is very low. The operation of a carbon concentrating mechanism (CCM) also makes the more abundant bicarbonate accessible for photosynthetic carbon fixation. Diatoms possess carbonic anhydrases as well as metabolic enzymes potentially involved in C4 pathways; however, the question as to whether a C4 pathway plays a general role in diatoms is not yet solved. While genome analyses indicate that the diatom Phaeodactylum tricornutum possesses all the enzymes required to operate a C4 pathway, silencing of the pyruvate orthophosphate dikinase (PPDK) in a genetically transformed cell line does not lead to reduced photosynthetic carbon fixation. In this study, we have determined the intracellular location of all enzymes potentially involved in C4-like carbon fixing pathways in P. tricornutum by expression of the respective proteins fused to green fluorescent protein (GFP), followed by fluorescence microscopy. Furthermore, we compared the results to known pathways and locations of enzymes in higher plants performing C3 or C4 photosynthesis. This approach revealed that the intracellular distribution of the investigated enzymes is quite different from the one observed in higher plants. In particular, the apparent lack of a plastidic decarboxylase in P. tricornutum indicates that this diatom does not perform a C4-like CCM.
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Affiliation(s)
- Daniela Ewe
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany.
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Masaaki Tachibana
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
- Lion Corporation Pharmaceutical Laboratories No.1, Odawara, Kanagawa, 256-0811, Japan
| | - Sae Kikutani
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
- Tech Manage Corp., Tokyo, 160-0023, Japan
| | - Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
| | | | - Grzegorz Konert
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus-Givat Ram, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
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18
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Kageyama H, Tanaka Y, Takabe T. Biosynthetic pathways of glycinebetaine in Thalassiosira pseudonana; functional characterization of enzyme catalyzing three-step methylation of glycine. Plant Physiol Biochem 2018; 127:248-255. [PMID: 29626705 DOI: 10.1016/j.plaphy.2018.03.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/08/2018] [Accepted: 03/27/2018] [Indexed: 05/15/2023]
Abstract
Betaine (trimethylglycine) is an important compatible solute that accumulates in response to abiotic stresses such as drought and salinity. Biosynthetic pathways of betaine have been extensively studied, but it remains to be clarified on algae. A diatom Thalassiosira pseudonana CCMP1335 is an important component of marine ecosystems. Here we show that the genome sequence of Thalassiosira suggests the presence of two biosynthetic pathways for betaine, via three step methylation of glycine and via two step oxidation of choline. The choline oxidation via choline dehydrogenase was suggested and its sequential characteristics were analyzed. A candidate gene TpORF1 for glycine methylation encodes a protein consisted of 574 amino acids with two putative tandem repeat methyltransferase domains. The TpORF1 was expressed in E. coli, and the purified protein was shown to synthesize betaine via three step methylation of glycine and designated as TpGSDMT. The proteins containing C-terminal half or N-terminal half were expressed in E. coli and exhibited the methyl transferase activities with different substrate specificity for glycine, sarcosine and dimethylglycine. Upregulation of TpGSDMT transcription and betaine levels were observed at high salinity, suggesting the importance of TpGSDMT for salt tolerance in T. pseudonana cells.
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Affiliation(s)
- Hakuto Kageyama
- Graduate School of Environmental and Human Sciences, Meijo University, Nagoya 468-8502, Japan
| | - Yoshito Tanaka
- Graduate School of Environmental and Human Sciences, Meijo University, Nagoya 468-8502, Japan
| | - Teruhiro Takabe
- Graduate School of Environmental and Human Sciences, Meijo University, Nagoya 468-8502, Japan; Research Institute, Meijo University, Nagoya 468-8502, Japan.
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Smith-Harding TJ, Beardall J, Mitchell JG. The role of external carbonic anhydrase in photosynthesis during growth of the marine diatom Chaetoceros muelleri. J Phycol 2017; 53:1159-1170. [PMID: 28771812 DOI: 10.1111/jpy.12572] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/22/2017] [Indexed: 06/07/2023]
Abstract
Carbon dioxide concentrating mechanisms (CCMs) act to improve the supply of CO2 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase. There is substantial evidence that in some microalgal species CCMs involve an external carbonic anhydrase (CAext ) and that CAext activity is induced by low CO2 concentrations in the growth medium. However, much of this work has been conducted on cells adapted to air-equilibrium concentrations of CO2 , rather than to changing CO2 conditions caused by growing microalgal populations. We investigated the role of CAext in inorganic carbon (Ci ) acquisition and photosynthesis at three sampling points during the growth cycle of the cosmopolitan marine diatom Chaetoceros muelleri. We observed that CAext activity increased with decreasing Ci , particularly CO2 , concentration, supporting the idea that CAext is modulated by external CO2 concentration. Additionally, we found that the contribution of CAext activity to carbon acquisition for photosynthesis varies over time, increasing between the first and second sampling points before decreasing at the last sampling point, where external pH was high. Lastly, decreases in maximum quantum yield of photosystem II (Fv /Fm ), chlorophyll, maximum relative electron transport rate, light harvesting efficiency (α) and maximum rates of Ci - saturated photosynthesis (Vmax ) were observed over time. Despite this decrease in photosynthetic capacity an up-regulation of CCM activity, indicated by a decreasing half-saturation constant for CO2 (K0.5 CO2 ), occurred over time. The flexibility of the CCM during the course of growth in C. muelleri may contribute to the reported dominance and persistence of this species in phytoplankton blooms.
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Affiliation(s)
- Tamsyne Jade Smith-Harding
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - James Gordon Mitchell
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
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20
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Gruber A, Kroth PG. Intracellular metabolic pathway distribution in diatoms and tools for genome-enabled experimental diatom research. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160402. [PMID: 28717012 PMCID: PMC5516111 DOI: 10.1098/rstb.2016.0402] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2017] [Indexed: 11/12/2022] Open
Abstract
Diatoms are important primary producers in the oceans and can also dominate other aquatic habitats. One reason for the success of this phylogenetically relatively young group of unicellular organisms could be the impressive redundancy and diversity of metabolic isoenzymes in diatoms. This redundancy is a result of the evolutionary origin of diatom plastids by a eukaryote-eukaryote endosymbiosis, a process that implies temporary redundancy of functionally complete eukaryotic genomes. During the establishment of the plastids, this redundancy was partially reduced via gene losses, and was partially retained via gene transfer to the nucleus of the respective host cell. These gene transfers required re-assignment of intracellular targeting signals, a process that simultaneously altered the intracellular distribution of metabolic enzymes compared with the ancestral cells. Genome annotation, the correct assignment of the gene products and the prediction of putative function, strongly depends on the correct prediction of the intracellular targeting of a gene product. Here again diatoms are very peculiar, because the targeting systems for organelle import are partially different to those in land plants. In this review, we describe methods of predicting intracellular enzyme locations, highlight findings of metabolic peculiarities in diatoms and present genome-enabled approaches to study their metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
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21
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McCarthy JK, Smith SR, McCrow JP, Tan M, Zheng H, Beeri K, Roth R, Lichtle C, Goodenough U, Bowler CP, Dupont CL, Allen AE. Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom. Plant Cell 2017; 29:2047-2070. [PMID: 28765511 PMCID: PMC5590495 DOI: 10.1105/tpc.16.00910] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 06/06/2017] [Accepted: 07/29/2017] [Indexed: 05/03/2023]
Abstract
The ecological prominence of diatoms in the ocean environment largely results from their superior competitive ability for dissolved nitrate (NO3-). To investigate the cellular and genetic basis of diatom NO3- assimilation, we generated a knockout in the nitrate reductase gene (NR-KO) of the model pennate diatom Phaeodactylum tricornutum In NR-KO cells, N-assimilation was abolished although NO3- transport remained intact. Unassimilated NO3- accumulated in NR-KO cells, resulting in swelling and associated changes in biochemical composition and physiology. Elevated expression of genes encoding putative vacuolar NO3- chloride channel transporters plus electron micrographs indicating enlarged vacuoles suggested vacuolar storage of NO3- Triacylglycerol concentrations in the NR-KO cells increased immediately following the addition of NO3-, and these increases coincided with elevated gene expression of key triacylglycerol biosynthesis components. Simultaneously, induction of transcripts encoding proteins involved in thylakoid membrane lipid recycling suggested more abrupt repartitioning of carbon resources in NR-KO cells compared with the wild type. Conversely, ribosomal structure and photosystem genes were immediately deactivated in NR-KO cells following NO3- addition, followed within hours by deactivation of genes encoding enzymes for chlorophyll biosynthesis and carbon fixation and metabolism. N-assimilation pathway genes respond uniquely, apparently induced simultaneously by both NO3- replete and deplete conditions.
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Affiliation(s)
- James K McCarthy
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
| | - Sarah R Smith
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
- Integrative Oceanography Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, California 92037
| | - John P McCrow
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
| | - Maxine Tan
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
| | - Hong Zheng
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
| | - Karen Beeri
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
| | - Robyn Roth
- Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Christian Lichtle
- Institut de Biologie de l'École Normale Supérieure, École Normale Supérieure, Paris Sciences et Lettres Research University, CNRS UMR8197 INSERM U1024, 75005 Paris, France
| | - Ursula Goodenough
- Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Chris P Bowler
- Institut de Biologie de l'École Normale Supérieure, École Normale Supérieure, Paris Sciences et Lettres Research University, CNRS UMR8197 INSERM U1024, 75005 Paris, France
| | - Christopher L Dupont
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
| | - Andrew E Allen
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037
- Integrative Oceanography Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, California 92037
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22
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Schmitz J, Srikanth NV, Hüdig M, Poschmann G, Lercher MJ, Maurino VG. The ancestors of diatoms evolved a unique mitochondrial dehydrogenase to oxidize photorespiratory glycolate. Photosynth Res 2017; 132:183-196. [PMID: 28247236 DOI: 10.1007/s11120-017-0355-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 02/08/2017] [Indexed: 05/15/2023]
Abstract
Like other oxygenic photosynthetic organisms, diatoms produce glycolate, a toxic intermediate, as a consequence of the oxygenase activity of Rubisco. Diatoms can remove glycolate through excretion and through oxidation as part of the photorespiratory pathway. The diatom Phaeodactylum tricornutum encodes two proteins suggested to be involved in glycolate metabolism: PtGO1 and PtGO2. We found that these proteins differ substantially from the sequences of experimentally characterized proteins responsible for glycolate oxidation in other species, glycolate oxidase (GOX) and glycolate dehydrogenase. We show that PtGO1 and PtGO2 are the only sequences of P. tricornutum homologous to GOX. Our phylogenetic analyses indicate that the ancestors of diatoms acquired PtGO1 during the proposed first secondary endosymbiosis with a chlorophyte alga, which may have previously obtained this gene from proteobacteria. In contrast, PtGO2 is orthologous to an uncharacterized protein in Galdieria sulphuraria, consistent with its acquisition during the secondary endosymbiosis with a red alga that gave rise to the current plastid. The analysis of amino acid residues at conserved positions suggests that PtGO2, which localizes to peroxisomes, may use substrates other than glycolate, explaining the lack of GOX activity we observe in vitro. Instead, PtGO1, while only very distantly related to previously characterized GOX proteins, evolved glycolate-oxidizing activity, as demonstrated by in gel activity assays and mass spectrometry analysis. PtGO1 localizes to mitochondria, consistent with previous suggestions that photorespiration in diatoms proceeds in these organelles. We conclude that the ancestors of diatoms evolved a unique alternative to oxidize photorespiratory glycolate: a mitochondrial dehydrogenase homologous to GOX able to use electron acceptors other than O2.
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Affiliation(s)
- Jessica Schmitz
- Institute of Developmental and Molecular Biology of Plants, Plant Molecular Physiology and Biotechnology Group, Heinrich Heine University, Universitätsstraße 1, and Cluster of Excellence on Plant Sciences (CEPLAS), 40225, Düsseldorf, Germany
| | - Nishtala V Srikanth
- Institute for Computer Science and Department of Biology, Heinrich Heine University, Universitätsstraße 1, and Cluster of Excellence on Plant Sciences (CEPLAS),, 40225, Düsseldorf, Germany
| | - Meike Hüdig
- Institute of Developmental and Molecular Biology of Plants, Plant Molecular Physiology and Biotechnology Group, Heinrich Heine University, Universitätsstraße 1, and Cluster of Excellence on Plant Sciences (CEPLAS), 40225, Düsseldorf, Germany
| | - Gereon Poschmann
- Molecular Proteomics Laboratory, Center for Biological and Medical Research (BMFZ), Heinrich Heine University, Düsseldorf, Germany
| | - Martin J Lercher
- Institute for Computer Science and Department of Biology, Heinrich Heine University, Universitätsstraße 1, and Cluster of Excellence on Plant Sciences (CEPLAS),, 40225, Düsseldorf, Germany
| | - Veronica G Maurino
- Institute of Developmental and Molecular Biology of Plants, Plant Molecular Physiology and Biotechnology Group, Heinrich Heine University, Universitätsstraße 1, and Cluster of Excellence on Plant Sciences (CEPLAS), 40225, Düsseldorf, Germany.
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23
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Davis A, Abbriano R, Smith SR, Hildebrand M. Clarification of Photorespiratory Processes and the Role of Malic Enzyme in Diatoms. Protist 2016; 168:134-153. [PMID: 28104538 DOI: 10.1016/j.protis.2016.10.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 10/03/2016] [Accepted: 10/08/2016] [Indexed: 11/20/2022]
Abstract
Evidence suggests that diatom photorespiratory metabolism is distinct from other photosynthetic eukaryotes in that there may be at least two routes for the metabolism of the photorespiratory metabolite glycolate. One occurs primarily in the mitochondria and is similar to the C2 photorespiratory pathway, and the other processes glycolate through the peroxisomal glyoxylate cycle. Genomic analysis has identified the presence of key genes required for glycolate oxidation, the glyoxylate cycle, and malate metabolism, however, predictions of intracellular localization can be ambiguous and require verification. This knowledge gap leads to uncertainties surrounding how these individual pathways operate, either together or independently, to process photorespiratory intermediates under different environmental conditions. Here, we combine in silico sequence analysis, in vivo protein localization techniques and gene expression patterns to investigate key enzymes potentially involved in photorespiratory metabolism in the model diatom Thalassiosira pseudonana. We demonstrate the peroxisomal localization of isocitrate lyase and the mitochondrial localization of malic enzyme and a glycolate oxidase. Based on these analyses, we propose an updated model for photorespiratory metabolism in T. pseudonana, as well as a mechanism by which C2 photorespiratory metabolism and its associated pathways may operate during silicon starvation and growth arrest.
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Affiliation(s)
- Aubrey Davis
- Marine Biology Research Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, U.S.A
| | - Raffaela Abbriano
- Marine Biology Research Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, U.S.A
| | - Sarah R Smith
- Integrative Oceanography Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, U.S.A.; J. Craig Venter Institute, La Jolla, CA, U.S.A
| | - Mark Hildebrand
- Marine Biology Research Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, U.S.A..
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24
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BenMoussa-Dahmen I, Chtourou H, Rezgui F, Sayadi S, Dhouib A. Salinity stress increases lipid, secondary metabolites and enzyme activity in Amphora subtropica and Dunaliella sp. for biodiesel production. Bioresour Technol 2016; 218:816-825. [PMID: 27428298 DOI: 10.1016/j.biortech.2016.07.022] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 06/06/2023]
Abstract
Amphora subtropica and Dunaliella sp. isolated from Tunisian biotopes were retained for their high lipid contents. Respective optimized parameters for rapid growth were: pH 9 and 10, light period 21 and 24h and temperature 31 and 34°C, respectively. After optimization, Amphora subtropica growth rate increased from 0.2 to 0.5day(-1) and Dunaliella sp. growth rate increased from 0.38 to 0.7day(-1). Amphora subtropica biomass production, productivity and lipid content increased from 0.3 to 0.7gL(-1)(dw), 69-100mgL(-1)d(-1)(dw) and 150-190gkg(-1)(dw), respectively, and Dunaliella sp. from 0.5 to 1.4gL(-1)(dw), 124-200mgL(-1)d(-1) (dw) and 190-280gkg(-1)(dw), respectively. Often to overcome trade-off between microalgae rapid growth and high lipid content which are often conflicting and very difficult to obtain at the same time, separation in a growth stage and a lipid accumulation stage is obvious. Salinity stress in a single stage of culture was studied. Compared to the optimal concentration of growth, excess or deficiency of NaCl engendered the same cellular responses by implication of oxidative stress systems and reactivation of defense and storage systems. Indeed, increasing salinity from 1M to 2M for Amphora subtropica or decreasing salinity from 3M to 2M for Dunaliella sp. have both increased lipids content from (220 and 280) to (350 and 430)gkg(-1), carotenoids from (1.8 and 2.4) to (2.3 and 3.7)pgcell(-1), TBARS amount from (10.4 and 5.3) to (12.1 and 10.7)nmolmg(-1) proteins and SOD activity from of (46.6 and 61.8) to (71.6 and 79.4)Umg(-1) proteins, respectively. With further improved fatty acids profile, the microalgae strains could be potent candidates for biofuel production.
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Affiliation(s)
- Ines BenMoussa-Dahmen
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, Sidi Mansour Street Km 6, PO Box «1177», 3018 Sfax, Tunisia.
| | - Haifa Chtourou
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, Sidi Mansour Street Km 6, PO Box «1177», 3018 Sfax, Tunisia
| | - Fatma Rezgui
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, Sidi Mansour Street Km 6, PO Box «1177», 3018 Sfax, Tunisia
| | - Sami Sayadi
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, Sidi Mansour Street Km 6, PO Box «1177», 3018 Sfax, Tunisia
| | - Abdelhafidh Dhouib
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, Sidi Mansour Street Km 6, PO Box «1177», 3018 Sfax, Tunisia
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25
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Kikutani S, Nakajima K, Nagasato C, Tsuji Y, Miyatake A, Matsuda Y. Thylakoid luminal θ-carbonic anhydrase critical for growth and photosynthesis in the marine diatom Phaeodactylum tricornutum. Proc Natl Acad Sci U S A 2016; 113:9828-33. [PMID: 27531955 PMCID: PMC5024579 DOI: 10.1073/pnas.1603112113] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The algal pyrenoid is a large plastid body, where the majority of the CO2-fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) resides, and it is proposed to be the hub of the algal CO2-concentrating mechanism (CCM) and CO2 fixation. The thylakoid membrane is often in close proximity to or penetrates the pyrenoid itself, implying there is a functional cooperation between the pyrenoid and thylakoid. Here, GFP tagging and immunolocalization analyses revealed that a previously unidentified protein, Pt43233, is targeted to the lumen of the pyrenoid-penetrating thylakoid in the marine diatom Phaeodactylum tricornutum The recombinant Pt43233 produced in Escherichia coli cells had both carbonic anhydrase (CA) and esterase activities. Furthermore, a Pt43233:GFP-fusion protein immunoprecipitated from P. tricornutum cells displayed a greater specific CA activity than detected for the purified recombinant protein. In an RNAi-generated Pt43233 knockdown mutant grown in atmospheric CO2 levels, photosynthetic dissolved inorganic carbon (DIC) affinity was decreased and growth was constantly retarded; in contrast, overexpression of Pt43233:GFP yielded a slightly greater photosynthetic DIC affinity. The discovery of a θ-type CA localized to the thylakoid lumen, with an essential role in photosynthetic efficiency and growth, strongly suggests the existence of a common role for the thylakoid-luminal CA with respect to the function of diverse algal pyrenoids.
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Affiliation(s)
- Sae Kikutani
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Kensuke Nakajima
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, Hokkaido 051-0013, Japan
| | - Yoshinori Tsuji
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Ai Miyatake
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan;
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26
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Young JN, Heureux AMC, Sharwood RE, Rickaby REM, Morel FMM, Whitney SM. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms. J Exp Bot 2016; 67:3445-56. [PMID: 27129950 PMCID: PMC4892730 DOI: 10.1093/jxb/erw163] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat (c)), oxygenation (k cat (o)), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23-68 µM), SC/O (57-116mol mol(-1)), and K O (413-2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat (c) for each diatom Rubisco showed less variation (2.1-3.7s(-1)), thus averting the canonical trade-off typically observed between K C and k cat (c) for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily.
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Affiliation(s)
- Jodi N Young
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Ana M C Heureux
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Robert E Sharwood
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Rosalind E M Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - François M M Morel
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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Eilers U, Dietzel L, Breitenbach J, Büchel C, Sandmann G. Identification of genes coding for functional zeaxanthin epoxidases in the diatom Phaeodactylum tricornutum. J Plant Physiol 2016; 192:64-70. [PMID: 26851888 DOI: 10.1016/j.jplph.2016.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 05/21/2023]
Abstract
Phaeodactylum tricornutum like other diatoms synthesizes fucoxanthin and diadinoxanthin as major carotenoid end products. The genes involved have recently been assigned for early pathway steps. Beyond β-carotene, only gene candidates for β-carotene hydroxylase, zeaxanthin epoxidase and zeaxanthin de-epoxidase have been proposed from the available genome sequence. The two latter enzymes may be involved in the two different xanthophyll cycles which operate in P. tricornutum. The function of three putative zeaxanthin epoxidase genes (zep) was addressed by pathway complementation in the Arabidopsis thaliana Zep mutant npq2. Genes zep2 and zep3 were able to restore zeaxanthin epoxidation and a functional xanthophyll cycle but the corresponding enzymes exhibited different catalytic activities. Zep3 functioned as a zeaxanthin epoxidase whereas Zep2 exhibited a broader substrate specificity additionally converting lutein to lutein-5,6-epoxide. Although zep1 was transcribed and the protein could be identified after import into the chloroplast in A. thaliana, Zep1 was found not to be functional in zeaxanthin epoxidation. The non-photochemical quenching kinetics of wild type A. thaliana was only restored in transformant npq2-zep3.
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Affiliation(s)
- Ulrike Eilers
- Department of Molecular Bioscience, J.W. Goethe University, Max-v-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Lars Dietzel
- Department of Molecular Bioscience, J.W. Goethe University, Max-v-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Jürgen Breitenbach
- Department of Molecular Bioscience, J.W. Goethe University, Max-v-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Claudia Büchel
- Department of Molecular Bioscience, J.W. Goethe University, Max-v-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Gerhard Sandmann
- Department of Molecular Bioscience, J.W. Goethe University, Max-v-Laue Str. 9, D-60438 Frankfurt, Germany.
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28
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Clement R, Dimnet L, Maberly SC, Gontero B. The nature of the CO2 -concentrating mechanisms in a marine diatom, Thalassiosira pseudonana. New Phytol 2016; 209:1417-27. [PMID: 26529678 DOI: 10.1111/nph.13728] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 09/25/2015] [Indexed: 05/19/2023]
Abstract
Diatoms are widespread in aquatic ecosystems where they may be limited by the supply of inorganic carbon. Their carbon dioxide-concentrating mechanisms (CCMs) involving transporters and carbonic anhydrases (CAs) are well known, but the contribution of a biochemical CCM involving C4 metabolism is contentious. The CCM(s) present in the marine-centric diatom, Thalassiosira pseudonana, were studied in cells exposed to high or low concentrations of CO2 , using a range of approaches. At low CO2 , cells possessed a CCM based on active uptake of CO2 (70% contribution) and bicarbonate, while at high CO2 , cells were restricted to CO2 . CA was highly and rapidly activated on transfer to low CO2 and played a key role because inhibition of external CA produced uptake kinetics similar to cells grown at high CO2 . The activities of phosphoenolpyruvate (PEP) carboxylase (PEPC) and the PEP-regenerating enzyme, pyruvate phosphate dikinase (PPDK), were lower in cells grown at low than at high CO2 . The ratios of PEPC and PPDK to ribulose bisphosphate carboxylase were substantially lower than 1, even at low CO2 . Our data suggest that the kinetic properties of this species results from a biophysical CCM and not from C4 type metabolism.
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Affiliation(s)
- Romain Clement
- Aix-Marseille Université CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, Marseille Cedex 20, 13402, France
| | - Laura Dimnet
- Aix-Marseille Université CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, Marseille Cedex 20, 13402, France
| | - Stephen C Maberly
- Centre for Ecology & Hydrology, Lake Ecosystems Group, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK
| | - Brigitte Gontero
- Aix-Marseille Université CNRS, BIP UMR 7281, 31 Chemin Joseph Aiguier, Marseille Cedex 20, 13402, France
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Bai X, Sun C, Xie J, Song H, Zhu Q, Su Y, Qian H, Fu Z. Effects of atrazine on photosynthesis and defense response and the underlying mechanisms in Phaeodactylum tricornutum. Environ Sci Pollut Res Int 2015; 22:17499-17507. [PMID: 26139402 DOI: 10.1007/s11356-015-4923-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/17/2015] [Indexed: 06/04/2023]
Abstract
Atrazine (ATZ) is a commonly used herbicide that has recently come under scrutiny due to potential environmental toxicity and contamination. In this study, we found that the administration of ATZ indeed leads to reduction of photosynthesis and oxidative stress in Phaeodactylum tricornutum at the treated doses higher than 100 μg L(-1) after 48 h. We further explored the effect of ATZ on photosystem II (PSII) and gene expression of electron transport chain. Collectively, our results may suggest that ATZ entered the chloroplasts in alga depending on ATZ's liposolubility and directly attacked on the electron transport chain, especially PSII, contributing to reactive oxygen species (ROS) burst. The increasing ROS could act as signals to induce or disturb the expression of photosynthesis-related genes, resulting in the imbalance of antioxidation and pro-oxidation in the alga.
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Affiliation(s)
- Xiaocui Bai
- Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
| | - Chongchong Sun
- Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
| | - Jun Xie
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
| | - Hao Song
- Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
| | - Qianqian Zhu
- Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
| | - Yiyuan Su
- Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
| | - Haifeng Qian
- Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China.
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China.
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Chinese Academy of Sciences, Urumqi, 830011, People's Republic. of China.
| | - Zhengwei Fu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032, People's Republic of China
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Weyman PD, Beeri K, Lefebvre SC, Rivera J, McCarthy JK, Heuberger AL, Peers G, Allen AE, Dupont CL. Inactivation of Phaeodactylum tricornutum urease gene using transcription activator-like effector nuclease-based targeted mutagenesis. Plant Biotechnol J 2015; 13:460-70. [PMID: 25302562 DOI: 10.1111/pbi.12254] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 07/22/2014] [Accepted: 08/06/2014] [Indexed: 05/21/2023]
Abstract
Diatoms are unicellular photosynthetic algae with promise for green production of fuels and other chemicals. Recent genome-editing techniques have greatly improved the potential of many eukaryotic genetic systems, including diatoms, to enable knowledge-based studies and bioengineering. Using a new technique, transcription activator-like effector nucleases (TALENs), the gene encoding the urease enzyme in the model diatom, Phaeodactylum tricornutum, was targeted for interruption. The knockout cassette was identified within the urease gene by PCR and Southern blot analyses of genomic DNA. The lack of urease protein was confirmed by Western blot analyses in mutant cell lines that were unable to grow on urea as the sole nitrogen source. Untargeted metabolomic analysis revealed a build-up of urea, arginine and ornithine in the urease knockout lines. All three intermediate metabolites are upstream of the urease reaction within the urea cycle, suggesting a disruption of the cycle despite urea production. Numerous high carbon metabolites were enriched in the mutant, implying a breakdown of cellular C and N repartitioning. The presented method improves the molecular toolkit for diatoms and clarifies the role of urease in the urea cycle.
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Affiliation(s)
- Philip D Weyman
- Department of Synthetic Biology and Bioenergy, J. Craig Venter Institute, La Jolla, CA, USA
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Alterio V, Langella E, De Simone G, Monti SM. Cadmium-containing carbonic anhydrase CDCA1 in marine diatom Thalassiosira weissflogii. Mar Drugs 2015; 13:1688-97. [PMID: 25815892 PMCID: PMC4413181 DOI: 10.3390/md13041688] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/12/2015] [Accepted: 03/17/2015] [Indexed: 01/03/2023] Open
Abstract
The Carbon Concentration Mechanism (CCM) allows phytoplakton species to accumulate the dissolved inorganic carbon (DIC) necessary for an efficient photosynthesis even under carbon dioxide limitation. In this mechanism of primary importance for diatoms, a key role is played by carbonic anhydrase (CA) enzymes which catalyze the reversible hydration of CO2, thus taking part in the acquisition of inorganic carbon for photosynthesis. A novel CA, named CDCA1, has been recently discovered in the marine diatom Thalassiosira weissflogii. CDCA1 is a cambialistic enzyme since it naturally uses Cd2+ as catalytic metal ion, but if necessary can spontaneously exchange Cd2+ to Zn2+. Here, the biochemical and structural features of CDCA1 enzyme will be presented together with its putative biotechnological applications for the detection of metal ions in seawaters.
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Affiliation(s)
- Vincenzo Alterio
- Institute of Biostructures and Bioimaging-National Research Council (CNR), Via Mezzocannone 16, I-80134 Naples, Italy.
| | - Emma Langella
- Institute of Biostructures and Bioimaging-National Research Council (CNR), Via Mezzocannone 16, I-80134 Naples, Italy.
| | - Giuseppina De Simone
- Institute of Biostructures and Bioimaging-National Research Council (CNR), Via Mezzocannone 16, I-80134 Naples, Italy.
| | - Simona Maria Monti
- Institute of Biostructures and Bioimaging-National Research Council (CNR), Via Mezzocannone 16, I-80134 Naples, Italy.
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Dolch LJ, Maréchal E. Inventory of fatty acid desaturases in the pennate diatom Phaeodactylum tricornutum. Mar Drugs 2015; 13:1317-39. [PMID: 25786062 PMCID: PMC4377986 DOI: 10.3390/md13031317] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/17/2015] [Accepted: 02/28/2015] [Indexed: 11/17/2022] Open
Abstract
The diatom Phaeodactylum is rich in very long chain polyunsaturated fatty acids (PUFAs). Fatty acid (FA) synthesis, elongation, and desaturation have been studied in depth in plants including Arabidopsis, but for secondary endosymbionts the full picture remains unclear. FAs are synthesized up to a chain length of 18 carbons inside chloroplasts, where they can be incorporated into glycerolipids. They are also exported to the ER for phospho- and betaine lipid syntheses. Elongation of FAs up to 22 carbons occurs in the ER. PUFAs can be reimported into plastids to serve as precursors for glycerolipids. In both organelles, FA desaturases are present, introducing double bonds between carbon atoms and giving rise to a variety of molecular species. In addition to the four desaturases characterized in Phaeodactylum (FAD2, FAD6, PtD5, PtD6), we identified eight putative desaturase genes. Combining subcellular localization predictions and comparisons with desaturases from other organisms like Arabidopsis, we propose a scheme at the whole cell level, including features that are likely specific to secondary endosymbionts.
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Affiliation(s)
- Lina-Juana Dolch
- Laboratory of Plant and Cell Physiology/Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS-CEA-Université Grenoble Alpes, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
| | - Eric Maréchal
- Laboratory of Plant and Cell Physiology/Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS-CEA-Université Grenoble Alpes, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
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Huysman MJJ, Tanaka A, Bowler C, Vyverman W, De Veylder L. Functional characterization of the diatom cyclin-dependent kinase A2 as a mitotic regulator reveals plant-like properties in a non-green lineage. BMC Plant Biol 2015; 15:86. [PMID: 25887918 PMCID: PMC4392632 DOI: 10.1186/s12870-015-0469-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/26/2015] [Indexed: 06/01/2023]
Abstract
BACKGROUND Cyclin-dependent kinases (CDKs) are crucial regulators of cell cycle progression in eukaryotes. The diatom CDKA2 was originally assigned to the classical A-type CDKs, but its cell cycle phase-specific transcription at the G2-to-M phase transition is typical for plant-specific B-type CDKs. RESULTS Here, we report the functional characterization of CDKA2 from the diatom Phaeodactylum tricornutum. Through a yeast two-hybrid library screen, CDKA2 was found to interact with the G2/M-specific CDK scaffolding factor CKS1. Localization of CDKA2 was found to be nuclear in interphase cells, while in cells undergoing cytokinesis, the signal extended to the cell division plane. In addition, overexpression of CDKA2 induced an overall reduction in the cell growth rate. Expression analysis of cell cycle marker genes in the overexpression lines indicates that this growth reduction is primarily due to a prolongation of the mitotic phase. CONCLUSIONS Our study indicates a role for CDKA2 during cell division in diatoms. The functional characterization of a CDK with clear CDKB properties in a non-green organism questions whether the current definition of B-type CDKs being plant-specific might need revision.
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Affiliation(s)
- Marie J J Huysman
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), 9052, Ghent, Belgium.
- Department of Plant Systems Biology, VIB, and Bioinformatics, Ghent University, 9052, Ghent, Belgium.
- Protistology and Aquatic Ecology, Department of Biology, Ghent University, 9000, Ghent, Belgium.
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8186, Institut National de la Santé et de la Recherche Médicale U1024, Ecole Normale Supérieure, 75230, Paris, Cedex 05, France.
| | - Atsuko Tanaka
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8186, Institut National de la Santé et de la Recherche Médicale U1024, Ecole Normale Supérieure, 75230, Paris, Cedex 05, France.
- Current address: Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, Hokkaido, 051-0013, Japan.
| | - Chris Bowler
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8186, Institut National de la Santé et de la Recherche Médicale U1024, Ecole Normale Supérieure, 75230, Paris, Cedex 05, France.
| | - Wim Vyverman
- Protistology and Aquatic Ecology, Department of Biology, Ghent University, 9000, Ghent, Belgium.
| | - Lieven De Veylder
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), 9052, Ghent, Belgium.
- Department of Plant Systems Biology, VIB, and Bioinformatics, Ghent University, 9052, Ghent, Belgium.
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Ran X, Liu R, Xu S, Bai F, Xu J, Yang Y, Shi J, Wu Z. Assessment of growth rate, chlorophyll a fluorescence, lipid peroxidation and antioxidant enzyme activity in Aphanizomenon flos-aquae, Pediastrum simplex and Synedra acus exposed to cadmium. Ecotoxicology 2015; 24:468-477. [PMID: 25471354 DOI: 10.1007/s10646-014-1395-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/21/2014] [Indexed: 06/04/2023]
Abstract
In this study, the effects of cadmium on the cyanobacterium Aphanizomenon flos-aquae, the green alga Pediastrum simplex and the diatom Synedra acus was evaluated on the basis of growth rate, chlorophyll a fluorescence, lipid peroxidation and antioxidant enzyme activity. The EC50 values (effective concentration inducing 50 % of growth inhibition) of cadmium in A. flos-aquae, P. simplex and S. acus were 1.18 ± 0.044, 4.32 ± 0.068 and 3.7 ± 0.055 mg/L, respectively. The results suggested that cadmium stress decreases growth rate and chlorophyll a concentration. The normalized chlorophyll a fluorescence transients significantly increased at cadmium concentrations of 5.0, 10.0 and 20.0 mg/L, but slightly decreased at concentrations of 0.2, 0.5 and 1.0 mg/L. The chlorophyll fluorescence parameters showed considerable variation among the three species, while lipid peroxidation and antioxidant enzyme activities showed a significant increase. Our results demonstrated that blockage of electron transport on the acceptor side of photosystem II is the mechanism responsible for cadmium toxicity in freshwater microalgae, and that the tolerance of the three species to cadmium was in the order green alga P. simplex > diatom S. acus > cyanobacterium A. flos-aquae.
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Affiliation(s)
- Xiaofei Ran
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing, 400715, People's Republic of China
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Young JN, Goldman JAL, Kranz SA, Tortell PD, Morel FMM. Slow carboxylation of Rubisco constrains the rate of carbon fixation during Antarctic phytoplankton blooms. New Phytol 2015; 205:172-81. [PMID: 25283055 DOI: 10.1111/nph.13021] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/27/2014] [Indexed: 05/19/2023]
Abstract
High-latitude oceans are areas of high primary production despite temperatures that are often well below the thermal optima of enzymes, including the key Calvin Cycle enzyme, Ribulose 1,5 bisphosphate carboxylase oxygenase (Rubisco). We measured carbon fixation rates, protein content and Rubisco abundance and catalytic rates during an intense diatom bloom in the Western Antarctic Peninsula (WAP) and in laboratory cultures of a psychrophilic diatom (Fragilariopsis cylindrus). At -1°C, the Rubisco turnover rate, kcat (c) , was 0.4 C s(-1) per site and the half saturation constant for CO2 was 15 μM (vs c. 3 C s(-1) per site and 50 μM at 20°C). To achieve high carboxylation rates, psychrophilic diatoms increased Rubisco abundance to c. 8% of biomass (vs c. 0.6% at 20°C), along with their total protein content, resulting in a low carbon : nitrogen ratio of c. 5. In psychrophilic diatoms, Rubisco must be almost fully active and near CO2 saturation to achieve carbon fixation rates observed in the WAP. Correspondingly, total protein concentrations were close to the highest ever measured in phytoplankton and likely near the maximum possible. We hypothesize that this high protein concentration, like that of Rubisco, is necessitated by slow enzyme rates, and that carbon fixation rates in the WAP are near a theoretical maximum.
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Affiliation(s)
- Jodi N Young
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
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Boller AJ, Thomas PJ, Cavanaugh CM, Scott KM. Isotopic discrimination and kinetic parameters of RubisCO from the marine bloom-forming diatom, Skeletonema costatum. Geobiology 2015; 13:33-43. [PMID: 25302659 DOI: 10.1111/gbi.12112] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 08/30/2014] [Indexed: 05/21/2023]
Abstract
The cosmopolitan, bloom-forming diatom, Skeletonema costatum, is a prominent primary producer in coastal oceans, fixing CO2 with ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) that is phylogenetically distinct from terrestrial plant RubisCO. RubisCOs are subdivided into groups based on sequence similarity of their large subunits (IA-ID, II, and III). ID is present in several major oceanic primary producers, including diatoms such as S. costatum, coccolithophores, and some dinoflagellates, and differs substantially in amino acid sequence from the well-studied IB enzymes present in most cyanobacteria and in green algae and plants. Despite this sequence divergence, and differences in isotopic discrimination apparent in other RubisCO enzymes, stable carbon isotope compositions of diatoms and other marine phytoplankton are generally interpreted assuming enzymatic isotopic discrimination similar to spinach RubisCO (IB). To interpret phytoplankton δ(13) C values, S. costatum RubisCO was characterized via sequence analysis, and measurement of its KCO2 and Vmax , and degree of isotopic discrimination. The sequence of this enzyme placed it among other diatom ID RubisCOs. Michaelis-Menten parameters were similar to other ID enzymes (KCO2 = 48.9 ± 2.8 μm; Vmax = 165.1 ± 6.3 nmol min(-1 ) mg(-1) ). However, isotopic discrimination (ε = [(12) k/(13) k - 1] × 1000) was low (18.5‰; 17.0-19.9, 95% CI) when compared to IA and IB RubisCOs (22-29‰), though not as low as ID from coccolithophore, Emiliania huxleyi (11.1‰). Variability in ε-values among RubisCOs from primary producers is likely reflected in δ(13) C values of oceanic biomass. Currently, δ(13) C variability is ascribed to physical or chemical factors (e.g. illumination, nutrient availability) and physiological responses to these factors (e.g. carbon-concentrating mechanisms). Estimating the importance of these factors from δ(13) C measurements requires an accurate ε-value, and a mass-balance model using the ε-value for S. costatum RubisCO is presented. Clearly, appropriate ε-values must be included in interpreting δ(13) C values of environmental samples.
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Affiliation(s)
- A J Boller
- Department of Integrative Biology, University of South Florida, Tampa, FL, USA
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Xue J, Niu YF, Huang T, Yang WD, Liu JS, Li HY. Genetic improvement of the microalga Phaeodactylum tricornutum for boosting neutral lipid accumulation. Metab Eng 2014; 27:1-9. [PMID: 25447640 DOI: 10.1016/j.ymben.2014.10.002] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 09/18/2014] [Accepted: 10/14/2014] [Indexed: 11/18/2022]
Abstract
To obtain fast growing oil-rich microalgal strains has been urgently demanded for microalgal biofuel. Malic enzyme (ME), which is involved in pyruvate metabolism and carbon fixation, was first characterized in microalgae here. Overexpression of Phaeodactylum tricornutum ME (PtME) significantly enhanced the expression of PtME and its enzymatic activity in transgenic P. tricornutum. The total lipid content in transgenic cells markedly increased by 2.5-fold and reached a record 57.8% of dry cell weight with a similar growth rate to wild type, thus keeping a high biomass. The neutral lipid content was further increased by 31% under nitrogen-deprivation treatment, still 66% higher than that of wild type. Transgenic microalgae cells exhibited obvious morphological changes, as the cells were shorter and thicker and contained larger oil bodies. Immuno-electron microscopy targeted PtME to the mitochondrion. This study markedly increased the oil content in microalgae, suggesting a new route for developing ideal microalgal strains for industrial biodiesel production.
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Affiliation(s)
- Jiao Xue
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China
| | - Ying-Fang Niu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China
| | - Tan Huang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China
| | - Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China.
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Misra N, Panda PK, Parida BK. Genome-wide identification and evolutionary analysis of algal LPAT genes involved in TAG biosynthesis using bioinformatic approaches. Mol Biol Rep 2014; 41:8319-32. [PMID: 25280541 DOI: 10.1007/s11033-014-3733-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/09/2014] [Indexed: 12/30/2022]
Abstract
Lysophosphatidyl acyltransferase (LPAT) is one of the major triacylglycerol synthesis enzymes, controlling the metabolic flow of lysophosphatidic acid to phosphatidic acid. Experimental studies in Arabidopsis have shown that LPAT activity is exhibited primarily by three distinct isoforms, namely the plastid-located LPAT1, the endoplasmic reticulum-located LPAT2, and the soluble isoform of LPAT (solLPAT). In this study, 24 putative genes representing all LPAT isoforms were identified from the analysis of 11 complete genomes including green algae, red algae, diatoms and higher plants. We observed LPAT1 and solLPAT genes to be ubiquitously present in nearly all genomes examined, whereas LPAT2 genes to have evolved more recently in the plant lineage. Phylogenetic analysis indicated that LPAT1, LPAT2 and solLPAT have convergently evolved through separate evolutionary paths and belong to three different gene families, which was further evidenced by their wide divergence at gene structure and sequence level. The genome distribution supports the hypothesis that each gene encoding a LPAT is not duplicated. Mapping of exon-intron structure of LPAT genes to the domain structure of proteins across different algal and plant species indicates that exon shuffling plays no role in the evolution of LPAT genes. Besides the previously defined motifs, several conserved consensus sequences were discovered which could be useful to distinguish different LPAT isoforms. Taken together, this study will enable the generation of experimental approximations to better understand the functional role of algal LPAT in lipid accumulation.
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Affiliation(s)
- Namrata Misra
- Academy of Scientific and Innovative Research, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, 751 013, Odisha, India
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Peng KT, Zheng CN, Xue J, Chen XY, Yang WD, Liu JS, Bai W, Li HY. Delta 5 fatty acid desaturase upregulates the synthesis of polyunsaturated fatty acids in the marine diatom Phaeodactylum tricornutum. J Agric Food Chem 2014; 62:8773-6. [PMID: 25109502 DOI: 10.1021/jf5031086] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Microalgae are important primary producers in the marine ecosystem and excellent sources of lipids and other bioactive compounds. The marine diatom Phaeodactylum tricornutum accumulates eicosapentaenoic acid (EPA, 20:5n-3) as its major component of fatty acids. To improve the EPA production, delta 5 desaturase, which plays a role in EPA biosynthetic pathway, was characterized in P. tricornutum. An annotated delta 5 desaturase PtD5b gene was cloned and overexpressed in P. tricornutum. The transgene was integrated into the genome demonstrated by Southern blot, and the overexpression of PtD5b was verified by qPCR and Western blot analysis. Fatty acid composition exhibited a significant increase in the unsaturated fatty acids. Monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) showed an increase of 75% and 64%, respectively. In particular, EPA showed an increase of 58% in engineered microalgae. Meanwhile, neutral lipid content showed an increase up to 65% in engineered microalgae. More importantly, engineered cells showed a similar growth rate with the wild type, thus keeping high biomass productivity. This work provides an effective way to improve the production of microalgal value-added bioproducts by metabolic engineering.
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Affiliation(s)
- Kun-Tao Peng
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science and §Department of Food Science, Jinan University , Guangzhou, Guangdong 510632, China
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41
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Tanaka R, Kikutani S, Mahardika A, Matsuda Y. Localization of enzymes relating to C4 organic acid metabolisms in the marine diatom, Thalassiosira pseudonana. Photosynth Res 2014; 121:251-63. [PMID: 24414292 DOI: 10.1007/s11120-014-9968-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 12/31/2013] [Indexed: 05/23/2023]
Abstract
In the genome of the marine diatom-Thalassiosira pseudonana, there are several putative genes encoding enzymes potentially constitute a classical C4 type biochemical CO2-concentrating mechanism. Two genes encode a carboxylation enzyme phosphoenolpyruvate carboxylase (PEPC)1 and PEPC2; and another two encode decarboxylation enzymes, NAD(+)-dependent malic enzyme (NAD-ME) and phosphoenolpyruvate carboxykinase (PEPCK). These genes were tagged by the enhanced-green fluorescence protein, egfp, ligated in the transformation vector, and transformed into the cells of T. pseudonana for localization of GFP fusion products. The PEPC1:GFP fusion was localized at the matrix of the periplastidal compartment, while the PEPC2:GFP fusion was localized at the mitochondria. The NAD-ME:GFP fusion was localized in the cytosol and the PEPCK:GFP fusion at the mitochondria. The transcripts level of NAD-ME was extremely low, and PEPCK transcript was significantly induced under the dark, suggesting that PEPCK is involved in the dark metabolism such as respiration and amino acid metabolism in the mitochondria. Treatments of low-CO2grown T. pseudonana cells with inhibitors for PEPCK and PEPC efficiently dissipated the maximum rate of photosynthesis while these treatments did not affect high-affinity photosynthesis. These data strongly suggest that classical C4 enzymes play little role in the CCM in T. pseudonana.
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Affiliation(s)
- Rie Tanaka
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan
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Ma YH, Wang X, Niu YF, Yang ZK, Zhang MH, Wang ZM, Yang WD, Liu JS, Li HY. Antisense knockdown of pyruvate dehydrogenase kinase promotes the neutral lipid accumulation in the diatom Phaeodactylum tricornutum. Microb Cell Fact 2014; 13:100. [PMID: 25106441 DOI: 10.1007/978-94-007-7864-1_127-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/03/2014] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Microalgae have been an emerging biofuel resource; however, the germplasm improvement has been slow due to the lack of molecular tools. Pyruvate dehydrogenase kinase (PDK) deactivates the pyruvate dehydrogenase complex (PDC) which catalyzes the oxidative decarboxylation of pyruvate. Acetyl-CoA production via PDC is important in plant tissues that are active in fatty acid synthesis. RESULTS A 1261-bp cDNA of a putative PDK gene (PtPDK) was cloned from a diatom Phaeodactylum tricornutum, and PtPDK antisense knockdown transgenic diatoms were generated. Both PtPDK transcript abundance and enzyme activity were reduced significantly due to antisense knockdown of PtPDK. Neutral lipid content of transgenic diatom cells increased up to 82% as determined by Nile red staining, and fatty acid composition was not altered. Transgenic cells showed slightly lower growth rate but similar cell size with the wild type, hence retaining similar biomass productivity. CONCLUSIONS This work first obtained a successful engineered diatom regulating a key gene involved in lipid metabolism. Our findings also provide powerful indications in enhancing microalgal lipid production by metabolic engineering for biofuel industry.
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Kettles NL, Kopriva S, Malin G. Insights into the regulation of DMSP synthesis in the diatom Thalassiosira pseudonana through APR activity, proteomics and gene expression analyses on cells acclimating to changes in salinity, light and nitrogen. PLoS One 2014; 9:e94795. [PMID: 24733415 PMCID: PMC3986220 DOI: 10.1371/journal.pone.0094795] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 03/20/2014] [Indexed: 01/05/2023] Open
Abstract
Despite the importance of dimethylsulphoniopropionate (DMSP) in the global sulphur cycle and climate regulation, the biological pathways underpinning its synthesis in marine phytoplankton remain poorly understood. The intracellular concentration of DMSP increases with increased salinity, increased light intensity and nitrogen starvation in the diatom Thalassiosira pseudonana. We used these conditions to investigate DMSP synthesis at the cellular level via analysis of enzyme activity, gene expression and proteome comparison. The activity of the key sulphur assimilatory enzyme, adenosine 5′-phosphosulphate reductase was not coordinated with increasing intracellular DMSP concentration. Under all three treatments coordination in the expression of sulphur assimilation genes was limited to increases in sulphite reductase transcripts. Similarly, proteomic 2D gel analysis only revealed an increase in phosphoenolpyruvate carboxylase following increases in DMSP concentration. Our findings suggest that increased sulphur assimilation might not be required for increased DMSP synthesis, instead the availability of carbon and nitrogen substrates may be important in the regulation of this pathway. This contrasts with the regulation of sulphur metabolism in higher plants, which generally involves up-regulation of several sulphur assimilatory enzymes. In T. pseudonana changes relating to sulphur metabolism were specific to the individual treatments and, given that little coordination was seen in transcript and protein responses across the three growth conditions, different patterns of regulation might be responsible for the increase in DMSP concentration seen under each treatment.
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Affiliation(s)
- Nicola Louise Kettles
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
- John Innes Centre, Norwich, United Kingdom
| | | | - Gill Malin
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
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Villanueva L, Rijpstra WIC, Schouten S, Damsté JSS. Genetic biomarkers of the sterol-biosynthetic pathway in microalgae. Environ Microbiol Rep 2014; 6:35-44. [PMID: 24596261 DOI: 10.1111/1758-2229.12106] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 09/09/2013] [Indexed: 05/26/2023]
Abstract
Sterols are cyclic isoprenoid lipids present in all eukaryotes. These compounds have been used to determine the composition of algal communities in marine and lake environments, and because of their preservation potential have been used to reconstruct the evolution of eukaryotes. In the last years, there have been major advances in understanding the sterol biosynthetic pathways and the enzymes involved. Here, we have explored the diversity and phylogenetic distribution of the gene coding the cycloartenol synthase (CS), a key enzyme of the phytosterol biosynthetic pathway. We propose a gene-based approach that can be used to assess the sterol-forming potential of algal groups. CS coding gene was annotated in genomes of microalgae using protein homology with previously annotated CS sequences. Primers for the detection of CS gene sequences of diatoms, one of the most dominant groups of microalgae, were designed and evaluated in cultures and environmental samples. A comparison of the phylogeny of the recovered CS sequences in combination with sequence data of the gene rbcL coding for the large subunit of the ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) demonstrates the potential of the CS gene as phylogenetic marker, as well as an indicator for the identity of sterol-producing organisms in the environment.
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Affiliation(s)
- Laura Villanueva
- Department of Marine Organic Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 179AB, Den Burg, The Netherlands
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Feng-Jiao L, Shun-Xing L, Feng-Ying Z, Xu-Guang H, Yue-Gang Z, Teng-Xiu T, Xue-Qing W. Risk assessment of nitrate and oxytetracycline addition on coastal ecosystem functions. Aquat Toxicol 2014; 146:76-81. [PMID: 24287139 DOI: 10.1016/j.aquatox.2013.10.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 10/23/2013] [Accepted: 10/30/2013] [Indexed: 06/02/2023]
Abstract
Diatoms dominate phytoplankton communities in the well-mixed coastal and upwelling regions. Coastal diatoms are often exposed to both aquaculture pollution and eutrophication. But how these exposures influence on coastal ecosystem functions are unknown. To examine these influences, a coastal centric diatom, Conticribra weissflogii was maintained at different concentrations of nitrate (N) and/or oxytetracycline (OTC). Algal density, cell growth cycle, protein, chlorophyll a, superoxide dismutase (SOD) activity, and malonaldehyde (MDA) were determined for the assessment of algal biomass, lifetime, nutritional value, photosynthesis and respiration, antioxidant capacity, and lipid peroxidation, respectively. When N addition was combined with OTC pollution, the cell growth cycles were shortened by 56-73%; algal density, SOD activities, the concentrations of chlorophyll a, protein, and MDA varied between 73 and 121%, 19 and 397%, 52 and 693%, 19 and 875%, and 66 and 2733% of the values observed in N addition experiments, respectively. According to P-value analysis, the influence of OTC on algal density and SOD activity was not significant, but the effect on cell growth cycle, protein, chlorophyll a, and MDA were significant (P<0.05). The influence of N addition with simultaneous OTC pollution on the above six end points was significant. Algal biomass, lifetime, nutrition, antioxidant capacity, lipid peroxidation, photosynthesis, and respiration were all affected by the addition of OTC and N. Coastal ecosystem functions were severely affected by N and OTC additions, and the influence was increased in the order: N<OTC<OTC+N. Thus, the simultaneous monitoring of N and OTC was necessary for the risk assessment of aquaculture pollution on coastal ecosystem functions.
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Affiliation(s)
- Liu Feng-Jiao
- Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Li Shun-Xing
- Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China.
| | - Zheng Feng-Ying
- Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China
| | - Huang Xu-Guang
- Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China
| | - Zuo Yue-Gang
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA 02747, USA
| | - Tu Teng-Xiu
- Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Wu Xue-Qing
- Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
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46
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Guo X, Jiang M, Wan X, Hu C, Gong Y. Identification and biochemical characterization of five long-chain acyl-coenzyme A synthetases from the diatom Phaeodactylum tricornutum. Plant Physiol Biochem 2014; 74:33-41. [PMID: 24257028 DOI: 10.1016/j.plaphy.2013.10.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/30/2013] [Indexed: 05/01/2023]
Abstract
Long-chain acyl-CoA synthetase (ACSL; EC 6.2.1.3) catalyzes the conversion of free fatty acid to acyl-CoA ester, which is necessary for many pathways of fatty acid and lipid metabolism. The diatom Phaeodactylum tricornutum genome encodes five putative ACSLs (PtACSL1-5) that contain several highly conserved motifs and share limited sequence similarities with each other and with other known ACSLs. To verify their long-chain acyl-CoA synthetase activities, five cDNAs encoding these PtACSLs were cloned, expressed, and tested for their ability to complement the Saccharomyces cerevisiae double mutant FAA1ΔFAA4Δ. Only two of five PtACSLs were able to restore growth, facilitate exogenous fatty acid uptake, and enhance storage lipid accumulation. We also found that P. tricornutum cells are capable of importing long-chain fatty acids from extracellular environment. The identification of P. tricornutum ACSLs will provide molecular basis for the study of ACSL-mediated lipid synthesis and metabolism in diatoms.
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Affiliation(s)
- Xiaojing Guo
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Mulan Jiang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Xia Wan
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Chuanjiong Hu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yangmin Gong
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China.
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Niu YF, Zhang MH, Li DW, Yang WD, Liu JS, Bai WB, Li HY. Improvement of neutral lipid and polyunsaturated fatty acid biosynthesis by overexpressing a type 2 diacylglycerol acyltransferase in marine diatom Phaeodactylum tricornutum. Mar Drugs 2013; 11:4558-69. [PMID: 24232669 PMCID: PMC3853745 DOI: 10.3390/md11114558] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 10/31/2013] [Accepted: 11/07/2013] [Indexed: 12/19/2022] Open
Abstract
Microalgae have been emerging as an important source for the production of bioactive compounds. Marine diatoms can store high amounts of lipid and grow quite quickly. However, the genetic and biochemical characteristics of fatty acid biosynthesis in diatoms remain unclear. Glycerophospholipids are integral as structural and functional components of cellular membranes, as well as precursors of various lipid mediators. In addition, diacylglycerol acyltransferase (DGAT) is a key enzyme that catalyzes the last step of triacylglyceride (TAG) biosynthesis. However, a comprehensive sequence-structure and functional analysis of DGAT in diatoms is lacking. In this study, an isoform of diacylglycerol acyltransferase type 2 of the marine diatom Phaeodactylum tricornutum was characterized. Surprisingly, DGAT2 overexpression in P. tricornutum stimulated more oil bodies, and the neutral lipid content increased by 35%. The fatty acid composition showed a significant increase in the proportion of polyunsaturated fatty acids; in particular, EPA was increased by 76.2%. Moreover, the growth rate of transgenic microalgae remained similar, thereby maintaining a high biomass. Our results suggest that increased DGAT2 expression could alter fatty acid profile in the diatom, and the results thus represent a valuable strategy for polyunsaturated fatty acid production by genetic manipulation.
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Affiliation(s)
- Ying-Fang Niu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
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Muto M, Kubota C, Tanaka M, Satoh A, Matsumoto M, Yoshino T, Tanaka T. Identification and functional analysis of delta-9 desaturase, a key enzyme in PUFA Synthesis, isolated from the oleaginous diatom Fistulifera. PLoS One 2013; 8:e73507. [PMID: 24039966 PMCID: PMC3764056 DOI: 10.1371/journal.pone.0073507] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 07/22/2013] [Indexed: 12/29/2022] Open
Abstract
Oleaginous microalgae are one of the promising resource of nonedible biodiesel fuel (BDF) feed stock alternatives. Now a challenge task is the decrease of the long-chain polyunsaturated fatty acids (PUFAs) content affecting on the BDF oxidative stability by using gene manipulation techniques. However, only the limited knowledge has been available concerning the fatty acid and PUFA synthesis pathways in microalgae. Especially, the function of Δ9 desaturase, which is a key enzyme in PUFA synthesis pathway, has not been determined in diatom. In this study, 4 Δ(9) desaturase genes (fD9desA, fD9desB, fD9desC and fD9desD) from the oleaginous diatom Fistulifera were newly isolated and functionally characterized. The putative Δ(9) acyl-CoA desaturases in the endoplasmic reticulum (ER) showed 3 histidine clusters that are well-conserved motifs in the typical Δ(9) desaturase. Furthermore, the function of these Δ(9) desaturases was confirmed in the Saccharomyces cerevisiae ole1 gene deletion mutant (Δole1). All the putative Δ(9) acyl-CoA desaturases showed Δ(9) desaturation activity for C16∶0 fatty acids; fD9desA and fD9desB also showed desaturation activity for C18∶0 fatty acids. This study represents the first functional analysis of Δ(9) desaturases from oleaginous microalgae and from diatoms as the first enzyme to introduce a double bond in saturated fatty acids during PUFA synthesis. The findings will provide beneficial insights into applying metabolic engineering processes to suppressing PUFA synthesis in this oleaginous microalgal strain.
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Affiliation(s)
- Masaki Muto
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
| | - Chihiro Kubota
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Masayoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
| | - Akira Satoh
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
- BT Development Group, Research and Development Section, Technology Center, Yamaha Motor Co. Ltd., Fukuroi, Shizuoka, Japan
| | - Mitsufumi Matsumoto
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
- Biotechnology Laboratory, Electric Power Development Co. Ltd., Yanagisaki-machi, Wakamatsu-ku, Kitakyusyu, Japan
| | - Tomoko Yoshino
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
- * E-mail:
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Li HM, Shi XY, Ding YY, Tang HJ. [Illumination's effect on the growth and nitrate reductase activity of typical red-tide algae in the East China Sea]. Huan Jing Ke Xue 2013; 34:3391-3397. [PMID: 24288981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Two typical red-tide algae, Skeletonema costatum and Prorocentrum donghaiense were selected as studied objects. The nitrate reductase activity (NRA) and the growth of the two algae under different illuminations through incubation experiment were studied. The illumination condition was consistent with in situ. Results showed that P. donghaiense and S. costatum could grow normally in the solar radiation ranged from 30-60 W x m(-2), and the growth curve was "S" type. However, when solar radiation was below 9 W x m(-2), the two alga could hardly grow. In the range of 0-60 W x m(-2), three parameters (NRAmax, micro(max), Bf) increased with the increasing of light intensity, indicating that the light intensity can influence the grow of alga indirectly through influencing the nitrate reductase activity. The micro(max) and NRAmax in unite volume of Skeletonema costatum were higher than those of Prorocentrum donghaiense, indicating that Skeletonema costatum can better utilize the nitrate than Prorocentrum donghaiense.
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Affiliation(s)
- Hong-mei Li
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
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Chmielowska-Bąk J, Izbiańska K, Deckert J. The toxic Doppelganger: on the ionic and molecular mimicry of cadmium. Acta Biochim Pol 2013; 60:369-374. [PMID: 23985538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/22/2013] [Accepted: 08/21/2013] [Indexed: 06/02/2023]
Abstract
Cadmium is a toxic heavy metal which can cause numerous alterations in cell functioning. Exposure to cadmium leads to generation of reactive oxygen species, disorders in membrane structure and functioning, inhibition of respiration, disturbances in ion homeostasis, perturbations in cell division, and initiation of apoptosis and necrosis. This heavy metal is considered a carcinogen by the Agency for Toxic Substances and Disease Registry. At least some of the described toxic effects could result from the ability of cadmium to mimic other divalent ions and alert signal transduction networks. This review describes the role of cadmium mimicry in its uptake, reactive oxygen species generation, alterations in calmodulin, Wnt/β-catenin and estrogen signaling pathways, and modulation of neurotransmission. The last section is dedicated to the single known case of a favorable function performed by cadmium mimicry: marine diatoms, which live in zinc deficient conditions, utilize cadmium as a cofactor in carbonic anhydrase - so far the only described cadmium enzyme.
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Affiliation(s)
- Jagna Chmielowska-Bąk
- Department of Plant Ecophysiology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
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