151
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Iwai M, Ikeda K, Shimojima M, Ohta H. Enhancement of extraplastidic oil synthesis in Chlamydomonas reinhardtii using a type-2 diacylglycerol acyltransferase with a phosphorus starvation-inducible promoter. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:808-19. [PMID: 24909748 PMCID: PMC4160818 DOI: 10.1111/pbi.12210] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/23/2014] [Accepted: 05/06/2014] [Indexed: 05/03/2023]
Abstract
When cultivated under stress conditions, many plants and algae accumulate oil. The unicellular green microalga Chlamydomonas reinhardtii accumulates neutral lipids (triacylglycerols; TAGs) during nutrient stress conditions. Temporal changes in TAG levels in nitrogen (N)- and phosphorus (P)-starved cells were examined to compare the effects of nutrient depletion on TAG accumulation in C. reinhardtii. TAG accumulation and fatty acid composition were substantially changed depending on the cultivation stage before nutrient starvation. Profiles of TAG accumulation also differed between N and P starvation. Logarithmic-growth-phase cells diluted into fresh medium showed substantial TAG accumulation with both N and P deprivation. N deprivation induced formation of oil droplets concomitant with the breakdown of thylakoid membranes. In contrast, P deprivation substantially induced accumulation of oil droplets in the cytosol and maintaining thylakoid membranes. As a consequence, P limitation accumulated more TAG both per cell and per culture medium under these conditions. To enhance oil accumulation under P deprivation, we constructed a P deprivation-dependent overexpressor of a Chlamydomonas type-2 diacylglycerol acyl-CoA acyltransferase (DGTT4) using a sulphoquinovosyldiacylglycerol 2 (SQD2) promoter, which was up-regulated during P starvation. The transformant strongly enhanced TAG accumulation with a slight increase in 18 : 1 content, which is a preferred substrate of DGTT4. These results demonstrated enhanced TAG accumulation using a P starvation-inducible promoter.
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Affiliation(s)
- Masako Iwai
- Center for Biological Resources and Informatics, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)Chiyoda-ku, Tokyo, Japan
| | - Keiko Ikeda
- Biomaterial Analysis Center, Technical Department, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
| | - Mie Shimojima
- Center for Biological Resources and Informatics, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
| | - Hiroyuki Ohta
- Center for Biological Resources and Informatics, Tokyo Institute of TechnologyMidori-ku, Yokohama, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)Chiyoda-ku, Tokyo, Japan
- Earth-Life Science Institute, Tokyo Institute of TechnologyMeguro-ku, Tokyo, Japan
- *Correspondence (Tel 81 45 924 5736; fax 81 45 924 5823; email )
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152
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Sim L, Beeren SR, Findinier J, Dauvillée D, Ball SG, Henriksen A, Palcic MM. Crystal structure of the Chlamydomonas starch debranching enzyme isoamylase ISA1 reveals insights into the mechanism of branch trimming and complex assembly. J Biol Chem 2014; 289:22991-23003. [PMID: 24993830 DOI: 10.1074/jbc.m114.565044] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The starch debranching enzymes isoamylase 1 and 2 (ISA1 and ISA2) are known to exist in a large complex and are involved in the biosynthesis and crystallization of starch. It is suggested that the function of the complex is to remove misplaced branches of growing amylopectin molecules, which would otherwise prevent the association and crystallization of adjacent linear chains. Here, we investigate the function of ISA1 and ISA2 from starch producing alga Chlamydomonas. Through complementation studies, we confirm that the STA8 locus encodes for ISA2 and sta8 mutants lack the ISA1·ISA2 heteromeric complex. However, mutants retain a functional dimeric ISA1 that is able to partly sustain starch synthesis in vivo. To better characterize ISA1, we have overexpressed and purified ISA1 from Chlamydomonas reinhardtii (CrISA1) and solved the crystal structure to 2.3 Å and in complex with maltoheptaose to 2.4 Å. Analysis of the homodimeric CrISA1 structure reveals a unique elongated structure with monomers connected end-to-end. The crystal complex reveals details about the mechanism of branch binding that explains the low activity of CrISA1 toward tightly spaced branches and reveals the presence of additional secondary surface carbohydrate binding sites.
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Affiliation(s)
- Lyann Sim
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and.
| | - Sophie R Beeren
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and
| | - Justin Findinier
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR 8576 CNRS-USTL, Bâtiment C9, Cité Scientifique, F-59655 Villeneuve d'Ascq, France
| | - David Dauvillée
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR 8576 CNRS-USTL, Bâtiment C9, Cité Scientifique, F-59655 Villeneuve d'Ascq, France
| | - Steven G Ball
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR 8576 CNRS-USTL, Bâtiment C9, Cité Scientifique, F-59655 Villeneuve d'Ascq, France
| | - Anette Henriksen
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and
| | - Monica M Palcic
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and
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153
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Lohman EJ, Gardner RD, Halverson LD, Peyton BM, Gerlach R. Carbon partitioning in lipids synthesized by Chlamydomonas reinhardtii when cultured under three unique inorganic carbon regimes. ALGAL RES 2014. [DOI: 10.1016/j.algal.2014.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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154
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Novoveská L, Henley WJ. Lab-Scale Testing of a Two-Stage Continuous Culture System for Microalgae. Ind Biotechnol (New Rochelle N Y) 2014. [DOI: 10.1089/ind.2013.0034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Lucie Novoveská
- Department of Botany, Oklahoma State University, Stillwater, OK
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155
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156
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Genome engineering empowers the diatom Phaeodactylum tricornutum for biotechnology. Nat Commun 2014; 5:3831. [PMID: 24871200 DOI: 10.1038/ncomms4831] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 04/08/2014] [Indexed: 02/07/2023] Open
Abstract
Diatoms, a major group of photosynthetic microalgae, have a high biotechnological potential that has not been fully exploited because of the paucity of available genetic tools. Here we demonstrate targeted and stable modifications of the genome of the marine diatom Phaeodactylum tricornutum, using both meganucleases and TALE nucleases. When nuclease-encoding constructs are co-transformed with a selectable marker, high frequencies of genome modifications are readily attained with 56 and 27% of the colonies exhibiting targeted mutagenesis or targeted gene insertion, respectively. The generation of an enhanced lipid-producing strain (45-fold increase in triacylglycerol accumulation) through the disruption of the UDP-glucose pyrophosphorylase gene exemplifies the power of genome engineering to harness diatoms for biofuel production.
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157
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Roche CM, Glass NL, Blanch HW, Clark DS. Engineering the filamentous fungusNeurospora crassafor lipid production from lignocellulosic biomass. Biotechnol Bioeng 2014; 111:1097-107. [DOI: 10.1002/bit.25211] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/03/2014] [Accepted: 02/06/2014] [Indexed: 01/14/2023]
Affiliation(s)
- Christine M. Roche
- The Chemical and Biomolecular Engineering Department; The University of California; Berkeley California 94720
- The Energy Biosciences Institute; The University of California; Berkeley California 94720
| | - N. Louise Glass
- The Energy Biosciences Institute; The University of California; Berkeley California 94720
- The Plant and Microbial Biology Department; The University of California; Berkeley California
| | - Harvey W. Blanch
- The Chemical and Biomolecular Engineering Department; The University of California; Berkeley California 94720
- The Energy Biosciences Institute; The University of California; Berkeley California 94720
| | - Douglas S. Clark
- The Chemical and Biomolecular Engineering Department; The University of California; Berkeley California 94720
- The Energy Biosciences Institute; The University of California; Berkeley California 94720
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158
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Li J, Han D, Wang D, Ning K, Jia J, Wei L, Jing X, Huang S, Chen J, Li Y, Hu Q, Xu J. Choreography of Transcriptomes and Lipidomes of Nannochloropsis Reveals the Mechanisms of Oil Synthesis in Microalgae. THE PLANT CELL 2014; 26:1645-1665. [PMID: 24692423 PMCID: PMC4036577 DOI: 10.1105/tpc.113.121418] [Citation(s) in RCA: 241] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/16/2014] [Accepted: 03/11/2014] [Indexed: 05/17/2023]
Abstract
To reveal the molecular mechanisms of oleaginousness in microalgae, transcriptomic and lipidomic dynamics of the oleaginous microalga Nannochloropsis oceanica IMET1 under nitrogen-replete (N+) and N-depleted (N-) conditions were simultaneously tracked. At the transcript level, enhanced triacylglycerol (TAG) synthesis under N- conditions primarily involved upregulation of seven putative diacylglycerol acyltransferase (DGAT) genes and downregulation of six other DGAT genes, with a simultaneous elevation of the other Kennedy pathway genes. Under N- conditions, despite downregulation of most de novo fatty acid synthesis genes, the pathways that shunt carbon precursors from protein and carbohydrate metabolic pathways into glycerolipid synthesis were stimulated at the transcript level. In particular, the genes involved in supplying carbon precursors and energy for de novo fatty acid synthesis, including those encoding components of the pyruvate dehydrogenase complex (PDHC), glycolysis, and PDHC bypass, and suites of specific transporters, were substantially upregulated under N- conditions, resulting in increased overall TAG production. Moreover, genes involved in the citric acid cycle and β-oxidation in mitochondria were greatly enhanced to utilize the carbon skeletons derived from membrane lipids and proteins to produce additional TAG or its precursors. This temporal and spatial regulation model of oil accumulation in microalgae provides a basis for improving our understanding of TAG synthesis in microalgae and will also enable more rational genetic engineering of TAG production.
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Affiliation(s)
- Jing Li
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Danxiang Han
- Laboratory for Algae Research and Biotechnology, Department of Applied Biological Sciences, Arizona State University, Mesa, Arizona 85212
| | - Dongmei Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Kang Ning
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Jing Jia
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyan Jing
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Shi Huang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Chen
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, Maryland 21202
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
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159
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Enhancement of lipid productivity by ethyl methane sulfonate-mediated random mutagenesis and proteomic analysis in Chlamydomonas reinhardtii. KOREAN J CHEM ENG 2014. [DOI: 10.1007/s11814-014-0007-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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160
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Eu YJ, Park HS, Kim DP, Wook Hong J. A microfluidic perfusion platform for cultivation and screening study of motile microalgal cells. BIOMICROFLUIDICS 2014; 8:024113. [PMID: 24803962 PMCID: PMC4000397 DOI: 10.1063/1.4871522] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 04/05/2014] [Indexed: 05/12/2023]
Abstract
Systematic screening of algal cells is getting huge interest due to their capability of producing lipid-based biodiesel. Here, we introduce a new microfluidic platform composed of an array of perfusion chambers designed for long-term cultivation and preliminary screening of motile microalgal cells through loading and releasing of cells to and from the chambers. The chemical environment in each perfusion chamber was independently controlled for 5 days. The effect of nitrogen-depletion on the lipid production, phototaxis behavior in the absence of Ca(2+), and cytotoxic effect of herbicide on microalgal cells was successfully monitored and compared with simultaneous control experiments on the platform. The present methodology could be extended to effective screening of algal cells and various cell lines for the production of biodiesel and other useful chemicals.
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Affiliation(s)
- Young-Jae Eu
- Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 305-764, South Korea ; National Center of Applied Microfluidic Chemistry, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyungbuk 790-784, South Korea
| | - Hye-Sun Park
- Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 305-764, South Korea ; National Center of Applied Microfluidic Chemistry, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyungbuk 790-784, South Korea
| | - Dong-Pyo Kim
- National Center of Applied Microfluidic Chemistry, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyungbuk 790-784, South Korea
| | - Jong Wook Hong
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, Alabama 36830, USA ; Department of Bionano Engineering, Hanyang University, Ansan 427-791, South Korea
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161
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The path to triacylglyceride obesity in the sta6 strain of Chlamydomonas reinhardtii. EUKARYOTIC CELL 2014; 13:591-613. [PMID: 24585881 DOI: 10.1128/ec.00013-14] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
When the sta6 (starch-null) strain of the green microalga Chlamydomonas reinhardtii is nitrogen starved in acetate and then "boosted" after 2 days with additional acetate, the cells become "obese" after 8 days, with triacylglyceride (TAG)-filled lipid bodies filling their cytoplasm and chloroplasts. To assess the transcriptional correlates of this response, the sta6 strain and the starch-forming cw15 strain were subjected to RNA-Seq analysis during the 2 days prior and 2 days after the boost, and the data were compared with published reports using other strains and growth conditions. During the 2 h after the boost, ∼425 genes are upregulated ≥2-fold and ∼875 genes are downregulated ≥2-fold in each strain. Expression of a small subset of "sensitive" genes, encoding enzymes involved in the glyoxylate and Calvin-Benson cycles, gluconeogenesis, and the pentose phosphate pathway, is responsive to culture conditions and genetic background as well as to boosting. Four genes-encoding a diacylglycerol acyltransferase (DGTT2), a glycerol-3-P dehydrogenase (GPD3), and two candidate lipases (Cre03.g155250 and Cre17.g735600)-are selectively upregulated in the sta6 strain. Although the bulk rate of acetate depletion from the medium is not boost enhanced, three candidate acetate permease-encoding genes in the GPR1/FUN34/YaaH superfamily are boost upregulated, and 13 of the "sensitive" genes are strongly responsive to the cell's acetate status. A cohort of 64 autophagy-related genes is downregulated by the boost. Our results indicate that the boost serves both to avert an autophagy program and to prolong the operation of key pathways that shuttle carbon from acetate into storage lipid, the combined outcome being enhanced TAG accumulation, notably in the sta6 strain.
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162
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Wang Y, Chen H, Yu O. A plant malonyl-CoA synthetase enhances lipid content and polyketide yield in yeast cells. Appl Microbiol Biotechnol 2014; 98:5435-47. [PMID: 24682482 DOI: 10.1007/s00253-014-5612-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/05/2014] [Accepted: 02/08/2014] [Indexed: 12/22/2022]
Abstract
Malonyl-CoA is the essential building block of natural products such as fatty acids, polyketides, and flavonoids. Engineering the biosynthesis of fatty acids is important for biofuel production while that of polyketides provides precursors of medicines and nutritional supplements. However, microorganisms maintain a small amount of cellular malonyl-CoA, which could limit production of lipid and polyketides under certain conditions. Malonyl-CoA concentration is regulated by multiple pathways and signals, and changes in intracellular malonyl-CoA often lead to complex alterations in metabolism. In the present work, overexpression of a plant malonyl-CoA synthetase gene (AAE13) in Saccharomyces cerevisiae resulted in 1.6- and 2.4-fold increases in lipid and resveratrol accumulation simultaneously. We also demonstrated that AAE13 partially complemented the temperature-sensitive acc1 mutant, replacing this key enzyme in central metabolism. Mechanistic analysis by CoA quantification and transcriptomic measurement suggested that increases in malonyl-CoA concentration were coupled with drastic reductions in other major CoA compounds and clear suppression of tricarboxylic acid cycle-related genes. These results suggest that malonyl-CoA is a critical target for fatty acid and polyketide engineering and that overexpression of malonyl-CoA synthetic enzymes needs to be combined with upregulation of CoA synthesis to maintain metastasis of central metabolism.
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Affiliation(s)
- Yechun Wang
- Donald Danforth Plant Science Center, 975 North Warson Road, Saint Louis, MO, 63132, USA
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163
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Garnier M, Carrier G, Rogniaux H, Nicolau E, Bougaran G, Saint-Jean B, Cadoret JP. Comparative proteomics reveals proteins impacted by nitrogen deprivation in wild-type and high lipid-accumulating mutant strains of Tisochrysis lutea. J Proteomics 2014; 105:107-20. [PMID: 24583506 DOI: 10.1016/j.jprot.2014.02.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 01/24/2014] [Accepted: 02/19/2014] [Indexed: 11/30/2022]
Abstract
UNLABELLED Understanding microalgal lipid accumulation under nitrogen starvation is of major interest for biomass feedstock, food and biofuel production. Using a domesticated oleaginous algae Tisochrysis lutea, we performed the first comparative proteomic analysis on the wild type strain and a selected lipid over-accumulating mutant. 2-DE analysis was made on these strains cultured in two metabolic conditions, with and without nitrogen deprivation, which revealed significant differences in proteomes according to both strain and nitrogen availability. Mass spectrometry allowed us to identify 37 proteins that were differentially expressed between the two strains, and 17 proteins regulated by nitrogen starvation concomitantly with lipid accumulation. The proteins identified are known to be involved in various metabolic pathways including lipid, carbohydrate, amino acid, energy and pigment metabolisms, photosynthesis, protein translation, stress response and cell division. Four candidates were selected for possible implication in the over-accumulation of lipids during nitrogen starvation. These include the plastid beta-ketoacyl-ACP reductase protein, the coccolith scale associated protein and two glycoside hydrolases involved in biosynthesis of fatty acids, carbon homeostasis and carbohydrate catabolism, respectively. This proteomic study confirms the impact of nitrogen starvation on overall metabolism and provides new perspectives to study the lipid over-accumulation in the prymnesiophyte haptophyte T. lutea. BIOLOGICAL SIGNIFICANCE This paper study consists of the first proteomic analysis on Tisochrysis lutea, a non-model marine microalga of interest for aquaculture and lipids production. Comparative proteomics revealed proteins putatively involved in the up-accumulation of neutral lipids in a mutant strain during nitrogen starvation. The results are of great importance for future works to improve lipid accumulation in microalgae of biotechnological interest for biofuel production. This article is part of a Special Issue entitled: Proteomics of non-model organisms.
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Affiliation(s)
- M Garnier
- Laboratoire BRM-PBA Ifremer, Nantes, France.
| | - G Carrier
- Laboratoire BRM-PBA Ifremer, Nantes, France
| | - H Rogniaux
- INRA, UR1268 Biopolymers Interactions Assemblies, F-44316 Nantes, France
| | - E Nicolau
- Laboratoire BRM-PBA Ifremer, Nantes, France
| | - G Bougaran
- Laboratoire BRM-PBA Ifremer, Nantes, France
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164
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Wase N, Black PN, Stanley BA, DiRusso CC. Integrated quantitative analysis of nitrogen stress response in Chlamydomonas reinhardtii using metabolite and protein profiling. J Proteome Res 2014; 13:1373-96. [PMID: 24528286 DOI: 10.1021/pr400952z] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nitrogen starvation induces a global stress response in microalgae that results in the accumulation of lipids as a potential source of biofuel. Using GC-MS-based metabolite and iTRAQ-labeled protein profiling, we examined and correlated the metabolic and proteomic response of Chlamydomonas reinhardtii under nitrogen stress. Key amino acids and metabolites involved in nitrogen sparing pathways, methyl group transfer reactions, and energy production were decreased in abundance, whereas certain fatty acids, citric acid, methionine, citramalic acid, triethanolamine, nicotianamine, trehalose, and sorbitol were increased in abundance. Proteins involved in nitrogen assimilation, amino acid metabolism, oxidative phosphorylation, glycolysis, TCA cycle, starch, and lipid metabolism were elevated compared with nonstressed cultures. In contrast, the enzymes of the glyoxylate cycle, one carbon metabolism, pentose phosphate pathway, the Calvin cycle, photosynthetic and light harvesting complex, and ribosomes were reduced. A noteworthy observation was that citrate accumulated during nitrogen stress coordinate with alterations in the enzymes that produce or utilize this metabolite, demonstrating the value of comparing protein and metabolite profiles to understand complex patterns of metabolic flow. Thus, the current study provides unique insight into the global metabolic adjustments leading to lipid storage during N starvation for application toward advanced biofuel production technologies.
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Affiliation(s)
- Nishikant Wase
- Department of Biochemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
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165
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Plancke C, Vigeolas H, Höhner R, Roberty S, Emonds-Alt B, Larosa V, Willamme R, Duby F, Onga Dhali D, Thonart P, Hiligsmann S, Franck F, Eppe G, Cardol P, Hippler M, Remacle C. Lack of isocitrate lyase in Chlamydomonas leads to changes in carbon metabolism and in the response to oxidative stress under mixotrophic growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:404-17. [PMID: 24286363 DOI: 10.1111/tpj.12392] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/30/2013] [Accepted: 11/21/2013] [Indexed: 05/10/2023]
Abstract
Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the tricarboxylic acid (TCA) cycle in which CO₂ is evolved. In this paper, a null icl mutant of the green microalga Chlamydomonas reinhardtii is described. Our data show that isocitrate lyase is required for growth in darkness on acetate (heterotrophic conditions), as well as for efficient growth in the light when acetate is supplied (mixotrophic conditions). Under these latter conditions, reduced acetate assimilation and concomitant reduced respiration occur, and biomass composition analysis reveals an increase in total fatty acid content, including neutral lipids and free fatty acids. Quantitative proteomic analysis by ¹⁴N/¹⁵N labelling was performed, and more than 1600 proteins were identified. These analyses reveal a strong decrease in the amounts of enzymes of the glyoxylate cycle and gluconeogenesis in parallel with a shift of the TCA cycle towards amino acid synthesis, accompanied by an increase in free amino acids. The decrease of the glyoxylate cycle and gluconeogenesis, as well as the decrease in enzymes involved in β-oxidation of fatty acids in the icl mutant are probably major factors that contribute to remodelling of lipids in the icl mutant. These modifications are probably responsible for the elevation of the response to oxidative stress, with significantly augmented levels and activities of superoxide dismutase and ascorbate peroxidase, and increased resistance to paraquat.
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Affiliation(s)
- Charlotte Plancke
- Genetics of Microorganisms, Institute of Botany, B22, University of Liege, 4000, Liege, Belgium
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166
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Triacylglyceride production and autophagous responses in Chlamydomonas reinhardtii depend on resource allocation and carbon source. EUKARYOTIC CELL 2014; 13:392-400. [PMID: 24413660 DOI: 10.1128/ec.00178-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To improve the economic viability of microalgal biodiesel, it will be essential to optimize the productivity of fuel molecules such as triacylglyceride (TAG) within the microalgal cell. To understand some of the triggers required for the metabolic switch to TAG production, we studied the effect of the carbon supply (acetate or CO₂) in Chlamydomonas reinhardtii (wild type and the starchless sta6 mutant) grown under low N availability. As expected, initial rates of TAG production were much higher when acetate was present than under strictly photosynthetic conditions, particularly for the sta6 mutant, which cannot allocate resources to starch. However, in both strains, TAG production plateaued after a few days in mixotrophic cultures, whereas under autotrophic conditions, TAG levels continued to rise. Moreover, the reduced growth of the sta6 mutant meant that the greatest productivity (measured as mg TAG liter⁻¹ day⁻¹) was found in the wild type growing autotrophically. Wild-type cells responded to low N by autophagy, as shown by degradation of polar (membrane) lipids and loss of photosynthetic pigments, and this was less in cells supplied with acetate. In contrast, little or no autophagy was observed in sta6 mutant cells, regardless of the carbon supply. Instead, very high levels of free fatty acids were observed in the sta6 mutant, suggesting considerable alteration in metabolism. These measurements show the importance of carbon supply and strain selection for lipid productivity. Our findings will be of use for industrial cultivation, where it will be preferable to use fast-growing wild-type strains supplied with gaseous CO₂ under autotrophic conditions rather than require an exogenous supply of organic carbon.
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167
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Remacle C, Eppe G, Coosemans N, Fernandez E, Vigeolas H. Combined intracellular nitrate and NIT2 effects on storage carbohydrate metabolism in Chlamydomonas. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:23-33. [PMID: 24187418 PMCID: PMC3883280 DOI: 10.1093/jxb/ert339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Microalgae are receiving increasing attention as alternative production systems for renewable energy such as biofuel. The photosynthetic alga Chlamydomonas reinhardtii is widely recognized as the model system to study all aspects of algal physiology, including the molecular mechanisms underlying the accumulation of starch and triacylglycerol (TAG), which are the precursors of biofuel. All of these pathways not only require a carbon (C) supply but also are strongly dependent on a source of nitrogen (N) to sustain optimal growth rate and biomass production. In order to gain a better understanding of the regulation of C and N metabolisms and the accumulation of storage carbohydrates, the effect of different N sources (NH4NO3 and ) on primary metabolism using various mutants impaired in either NIA1, NIT2 or both loci was performed by metabolic analyses. The data demonstrated that, using NH4NO3, nia1 strain displayed the most striking phenotype, including an inhibition of growth, accumulation of intracellular nitrate, and strong starch and TAG accumulation. The measurements of the different C and N intermediate levels (amino, organic, and fatty acids), together with the determination of acetate and remaining in the medium, clearly excluded the hypothesis of a slower and acetate assimilation in this mutant in the presence of NH4NO3. The results provide evidence of the implication of intracellular nitrate and NIT2 in the control of C partitioning into different storage carbohydrates under mixotrophic conditions in Chlamydomonas. The underlying mechanisms and implications for strategies to increase biomass yield and storage product composition in oleaginous algae are discussed.
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Affiliation(s)
- C. Remacle
- University of Liege, Institute of Botany, B22, Genetics of Microorganisms, 4000 Liege, Belgium
| | - G. Eppe
- University of Liege, Inorganic Analytical Chemistry, LSM-CART, Allée de la Chimie B6c, 4000 Liege, Belgium
| | - N. Coosemans
- University of Liege, Institute of Botany, B22, Genetics of Microorganisms, 4000 Liege, Belgium
| | - E. Fernandez
- Departamento de Bioquımica y Biologıa Molecular, Facultad de Ciencias, Universidad de Cordoba, Campus de Rabanales, 14071 Cordoba, Spain
| | - H. Vigeolas
- University of Liege, Institute of Botany, B22, Genetics of Microorganisms, 4000 Liege, Belgium
- * To whom correspondence should be addressed.
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168
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Velmurugan N, Sung M, Yim SS, Park MS, Yang JW, Jeong KJ. Systematically programmed adaptive evolution reveals potential role of carbon and nitrogen pathways during lipid accumulation in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:117. [PMID: 25258645 PMCID: PMC4174265 DOI: 10.1186/s13068-014-0117-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 07/22/2014] [Indexed: 05/11/2023]
Abstract
BACKGROUND The concept of adaptive evolution implies underlying genetic mutations conferring a selective advantage to an organism under particular environmental conditions. Thus, a flow cytometry-based strategy was used to study the adaptive evolution in Chlamydomonas reinhardtii wild-type strain CC124 and starchless mutant sta6-1 cells, with respect to lipid metabolism under nitrogen-(N) depleted and -replete conditions. RESULTS The successive sorting and regeneration of the top 25,000 high-lipid content cells of CC124 and sta6-1, combined with nitrogen starvation, led to the generation of a new population with an improved lipid content when compared to the original populations (approximately 175% and 50% lipid increase in sta6-1 and CC124, respectively). During the adaptive evolution period, the major fatty acid components observed in cells were C16:0, C16:1, C18:0, and C18:1-3, and elemental analysis revealed that cellular carbon to nitrogen ratio increased at the end of adaptive evolution period In order to gain an insight into highly stimulated intracellular lipid accumulation in CC124 and sta6-1 resulting from the adaptive evolution, proteomics analyses of newly generated artificial high-lipid content populations were performed. Functional classifications showed the heightened regulation of the major chlorophyll enzymes, and the enzymes involved in carbon fixation and uptake, including chlorophyll-ab-binding proteins and Rubisco activase. The key control protein (periplasmic L-amino acid oxidase (LAO1)) of carbon-nitrogen integration was specifically overexpressed. Glutathione-S-transferases and esterase, the enzymes involved in lipid-metabolism and lipid-body associated proteins, were also induced during adaptive evolution. CONCLUSIONS Adaptive evolution results demonstrate the potential role of photosynthesis in terms of carbon partitioning, flux, and fixation and carbon-nitrogen metabolism during lipid accumulation in microalgae. This strategy can be used as a new tool to develop C. reinhardtii strains and other microalgal strains with desired phenotypes such as high lipid accumulation.
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Affiliation(s)
- Natarajan Velmurugan
- />Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Minji Sung
- />Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Sung Sun Yim
- />Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Min S Park
- />Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
- />Bioscience Division, Los Alamos National Laboratory, Bikini Atoll Road, Los Alamos, NM 87545 USA
| | - Ji Won Yang
- />Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Ki Jun Jeong
- />Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
- />KI for the Biocentury, KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
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169
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de Jaeger L, Verbeek REM, Draaisma RB, Martens DE, Springer J, Eggink G, Wijffels RH. Superior triacylglycerol (TAG) accumulation in starchless mutants of Scenedesmus obliquus: (I) mutant generation and characterization. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:69. [PMID: 24920957 PMCID: PMC4052810 DOI: 10.1186/1754-6834-7-69] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/14/2014] [Indexed: 05/21/2023]
Abstract
BACKGROUND Microalgae are a promising platform for producing neutral lipids, to be used in the application for biofuels or commodities in the feed and food industry. A very promising candidate is the oleaginous green microalga Scenedesmus obliquus, because it accumulates up to 45% w/w triacylglycerol (TAG) under nitrogen starvation. Under these conditions, starch is accumulated as well. Starch can amount up to 38% w/w under nitrogen starvation, which is a substantial part of the total carbon captured. When aiming for optimized TAG production, blocking the formation of starch could potentially increase carbon allocation towards TAG. In an attempt to increase TAG content, productivity and yield, starchless mutants of this high potential strain were generated using UV mutagenesis. Previous studies in Chlamydomonas reinhardtii have shown that blocking the starch synthesis yields higher TAG contents, although these TAG contents do not surpass those of oleaginous microalgae yet. So far no starchless mutants in oleaginous green microalgae have been isolated that result in higher TAG productivities. RESULTS Five starchless mutants have been isolated successfully from over 3,500 mutants. The effect of the mutation on biomass and total fatty acid (TFA) and TAG productivity under nitrogen-replete and nitrogen-depleted conditions was studied. All five starchless mutants showed a decreased or completely absent starch content. In parallel, an increased TAG accumulation rate was observed for the starchless mutants and no substantial decrease in biomass productivity was perceived. The most promising mutant showed an increase in TFA productivity of 41% at 4 days after nitrogen depletion, reached a TAG content of 49.4% (% of dry weight) and had no substantial change in biomass productivity compared to the wild type. CONCLUSIONS The improved S. obliquus TAG production strains are the first starchless mutants in an oleaginous green microalga that show enhanced TAG content under photoautotrophic conditions. These results can pave the way towards a more feasible microalgae-driven TAG production platform.
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Affiliation(s)
- Lenny de Jaeger
- Bioprocess Engineering and AlgaePARC, Wageningen University and Research Centre, PO Box 8129, 6700 EV Wageningen, The Netherlands
- Food and Biobased Research and AlgaePARC, Wageningen University and Research Centre, PO Box 17, 6700 AA Wageningen, The Netherlands
| | - Ruben EM Verbeek
- Bioprocess Engineering and AlgaePARC, Wageningen University and Research Centre, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - René B Draaisma
- Unilever Research and Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Dirk E Martens
- Bioprocess Engineering and AlgaePARC, Wageningen University and Research Centre, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Jan Springer
- Food and Biobased Research and AlgaePARC, Wageningen University and Research Centre, PO Box 17, 6700 AA Wageningen, The Netherlands
| | - Gerrit Eggink
- Bioprocess Engineering and AlgaePARC, Wageningen University and Research Centre, PO Box 8129, 6700 EV Wageningen, The Netherlands
- Food and Biobased Research and AlgaePARC, Wageningen University and Research Centre, PO Box 17, 6700 AA Wageningen, The Netherlands
| | - René H Wijffels
- Bioprocess Engineering and AlgaePARC, Wageningen University and Research Centre, PO Box 8129, 6700 EV Wageningen, The Netherlands
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170
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Zhu S, Huang W, Xu J, Wang Z, Xu J, Yuan Z. Metabolic changes of starch and lipid triggered by nitrogen starvation in the microalga Chlorella zofingiensis. BIORESOURCE TECHNOLOGY 2014; 152:292-8. [PMID: 24308944 DOI: 10.1016/j.biortech.2013.10.092] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/24/2013] [Accepted: 10/28/2013] [Indexed: 05/03/2023]
Abstract
The aim of this research was to study the metabolic changes of starch and lipid biosynthesis in the microalga Chlorella zofingiensis under nitrogen starvation in comparison to nitrogen abundant condition. C. zonfingiensis showed a rapid growth and kept stable chlorophyll content when grown in nitrogen-replete medium, while a severe inhibition of cell growth and a sharp degradation of chlorophyll occurred under nitrogen depletion. Nitrogen-replete C. zonfingiensis cells possessed basal levels of starch and lipid. Upon nitrogen starvation, both starch and lipid increased greatly within cells, but starch synthesis preceded lipid accumulation. After 2 days of stress condition, starch was partially degraded, possibly to support lipid synthesis. It was speculated that starch accumulation acted as a quick response to environmental stress, whereas lipid served as long-term energy storage. Additionally, C. zonfingiensis tends to lower the degree of unsaturation in response to nitrogen starvation which is desirable for biodiesel production.
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Affiliation(s)
- Shunni Zhu
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Wei Huang
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Jin Xu
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zhongming Wang
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Jingliang Xu
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zhenhong Yuan
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China.
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171
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Wei L, Derrien B, Gautier A, Houille-Vernes L, Boulouis A, Saint-Marcoux D, Malnoë A, Rappaport F, de Vitry C, Vallon O, Choquet Y, Wollman FA. Nitric oxide-triggered remodeling of chloroplast bioenergetics and thylakoid proteins upon nitrogen starvation in Chlamydomonas reinhardtii. THE PLANT CELL 2014; 26:353-72. [PMID: 24474630 PMCID: PMC3963581 DOI: 10.1105/tpc.113.120121] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/04/2013] [Accepted: 01/10/2014] [Indexed: 05/18/2023]
Abstract
Starving microalgae for nitrogen sources is commonly used as a biotechnological tool to boost storage of reduced carbon into starch granules or lipid droplets, but the accompanying changes in bioenergetics have been little studied so far. Here, we report that the selective depletion of Rubisco and cytochrome b6f complex that occurs when Chlamydomonas reinhardtii is starved for nitrogen in the presence of acetate and under normoxic conditions is accompanied by a marked increase in chlororespiratory enzymes, which converts the photosynthetic thylakoid membrane into an intracellular matrix for oxidative catabolism of reductants. Cytochrome b6f subunits and most proteins specifically involved in their biogenesis are selectively degraded, mainly by the FtsH and Clp chloroplast proteases. This regulated degradation pathway does not require light, active photosynthesis, or state transitions but is prevented when respiration is impaired or under phototrophic conditions. We provide genetic and pharmacological evidence that NO production from intracellular nitrite governs this degradation pathway: Addition of a NO scavenger and of two distinct NO producers decrease and increase, respectively, the rate of cytochrome b6f degradation; NO-sensitive fluorescence probes, visualized by confocal microscopy, demonstrate that nitrogen-starved cells produce NO only when the cytochrome b6f degradation pathway is activated.
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Affiliation(s)
- Lili Wei
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Benoit Derrien
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Arnaud Gautier
- École Normale Supérieure,
Département de Chimie, Unité Mixte de Recherche, CNRS–Ecole
Normale Supérieure–Université Pierre et Marie Curie 8640,
75231 Paris Cedex 05, France
| | - Laura Houille-Vernes
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Alix Boulouis
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Denis Saint-Marcoux
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Alizée Malnoë
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Fabrice Rappaport
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Catherine de Vitry
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Olivier Vallon
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Yves Choquet
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
| | - Francis-André Wollman
- Unité Mixte de Recherche 7141,
CNRS/Université Pierre et Marie Curie, Institut de Biologie
Physico-Chimique, F-75005 Paris, France
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172
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Velmurugan N, Sung M, Yim SS, Park MS, Yang JW, Jeong KJ. Systematically programmed adaptive evolution reveals potential role of carbon and nitrogen pathways during lipid accumulation in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2014. [PMID: 25258645 DOI: 10.1186/preaccept-1279724404120676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND The concept of adaptive evolution implies underlying genetic mutations conferring a selective advantage to an organism under particular environmental conditions. Thus, a flow cytometry-based strategy was used to study the adaptive evolution in Chlamydomonas reinhardtii wild-type strain CC124 and starchless mutant sta6-1 cells, with respect to lipid metabolism under nitrogen-(N) depleted and -replete conditions. RESULTS The successive sorting and regeneration of the top 25,000 high-lipid content cells of CC124 and sta6-1, combined with nitrogen starvation, led to the generation of a new population with an improved lipid content when compared to the original populations (approximately 175% and 50% lipid increase in sta6-1 and CC124, respectively). During the adaptive evolution period, the major fatty acid components observed in cells were C16:0, C16:1, C18:0, and C18:1-3, and elemental analysis revealed that cellular carbon to nitrogen ratio increased at the end of adaptive evolution period In order to gain an insight into highly stimulated intracellular lipid accumulation in CC124 and sta6-1 resulting from the adaptive evolution, proteomics analyses of newly generated artificial high-lipid content populations were performed. Functional classifications showed the heightened regulation of the major chlorophyll enzymes, and the enzymes involved in carbon fixation and uptake, including chlorophyll-ab-binding proteins and Rubisco activase. The key control protein (periplasmic L-amino acid oxidase (LAO1)) of carbon-nitrogen integration was specifically overexpressed. Glutathione-S-transferases and esterase, the enzymes involved in lipid-metabolism and lipid-body associated proteins, were also induced during adaptive evolution. CONCLUSIONS Adaptive evolution results demonstrate the potential role of photosynthesis in terms of carbon partitioning, flux, and fixation and carbon-nitrogen metabolism during lipid accumulation in microalgae. This strategy can be used as a new tool to develop C. reinhardtii strains and other microalgal strains with desired phenotypes such as high lipid accumulation.
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Affiliation(s)
- Natarajan Velmurugan
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Minji Sung
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Sung Sun Yim
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Min S Park
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea ; Bioscience Division, Los Alamos National Laboratory, Bikini Atoll Road, Los Alamos, NM 87545 USA
| | - Ji Won Yang
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
| | - Ki Jun Jeong
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea ; KI for the Biocentury, KAIST, 291 Daehak-ro, Yuseong-gu Daejeon, 305-701 Republic of Korea
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173
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Therien JB, Zadvornyy OA, Posewitz MC, Bryant DA, Peters JW. Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:154. [PMID: 25364380 PMCID: PMC4216383 DOI: 10.1186/s13068-014-0154-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/02/2014] [Indexed: 05/05/2023]
Abstract
BACKGROUND The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. Here we demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC 7002. RESULTS Optimal growth conditions for co-cultivation of C. reinhardtii with wild-type and mutant strains of Synechococcus sp. 7002 were established. In co-culture, acetate produced by a glycogen synthase knockout mutant of Synechococcus sp. PCC 7002 was able to support the growth of a lipid-accumulating mutant strain of C. reinhardtii defective in starch production. Encapsulation of Synechococcus sp. PCC 7002 using an alginate matrix was successfully employed in co-cultures to limit growth and maintain the stability. CONCLUSIONS The ability of immobilized strains of the cyanobacterium Synechococcus sp. PCC 7002 to produce acetate at a level adequate to support the growth of lipid-accumulating strains of C. reinhartdii offers a potentially practical, photosynthetic alternative to providing exogenous acetate into growth media.
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Affiliation(s)
- Jesse B Therien
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
| | - Oleg A Zadvornyy
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
| | - Matthew C Posewitz
- />Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401 USA
| | - Donald A Bryant
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
- />Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802 USA
| | - John W Peters
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
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174
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Detailed identification of fatty acid isomers sheds light on the probable precursors of triacylglycerol accumulation in photoautotrophically grown Chlamydomonas reinhardtii. EUKARYOTIC CELL 2013; 13:256-66. [PMID: 24337111 DOI: 10.1128/ec.00280-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Chlamydomonas reinhardtii is a model alga for studying triacylglycerol (TAG) accumulation in the photosynthetic production of biofuel. Previous studies were conducted under photoheterotrophic growth conditions in medium supplemented with acetate and/or ammonium. We wanted to demonstrate TAG accumulation under truly photoautotrophic conditions without reduced elements. We first reidentified all lipid components and fatty acids by mass spectrometry, because the currently used identification knowledge relies on data obtained in the 1980s. Accordingly, various isomers of fatty acids, which are potentially useful in tracing the flow of fatty acids leading to the accumulation of TAG, were detected. In strain CC1010 grown under photoautotrophic conditions, TAG accumulated to about 57.5 mol% of total lipids on a mole fatty acid basis after the transfer to nitrogen-deficient conditions. The content of monogalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol decreased drastically. The accumulated TAG contained 16:0 as the major acid and 16:4(4,7,10,13), 18:2(9,12), and 18:3(9,12,15), which are typically found in chloroplast lipids. Additionally, 18:1(11) and 18:3(5,9,12), which are specific to extrachloroplast lipids, were also abundant in the accumulated TAG. Photosynthesis and respiration slowed markedly after the shift to nitrogen-deficient conditions. These results suggest that fatty acids for the production of TAG were supplied not only from chloroplast lipids but also from other membranes within the cells, although the possibility of de novo synthesis cannot be excluded. Under nitrogen-replete conditions, supplementation with a high concentration of CO2 promoted TAG production in the cells grown photoautotrophically, opening up the possibility to the continuous production of TAG using CO2 produced by industry.
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175
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Korkhovoy VI, Blume YB. Biodiesel from microalgae: Ways for increasing the effectiveness of lipid accumulation by genetic engineering methods. CYTOL GENET+ 2013. [DOI: 10.3103/s0095452713060030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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176
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Cagnon C, Mirabella B, Nguyen HM, Beyly-Adriano A, Bouvet S, Cuiné S, Beisson F, Peltier G, Li-Beisson Y. Development of a forward genetic screen to isolate oil mutants in the green microalga Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:178. [PMID: 24295516 PMCID: PMC4176504 DOI: 10.1186/1754-6834-6-178] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/20/2013] [Indexed: 05/06/2023]
Abstract
BACKGROUND Oils produced by microalgae are precursors to biodiesel. To achieve a profitable production of biodiesel from microalgae, identification of factors governing oil synthesis and turnover is desirable. The green microalga Chlamydomonas reinhardtii is amenable to genetic analyses and has recently emerged as a model to study oil metabolism. However, a detailed method to isolate various types of oil mutants that is adapted to Chlamydomonas has not been reported. RESULTS We describe here a forward genetic approach to isolate mutants altered in oil synthesis and turnover from C. reinhardtii. It consists of a three-step screening procedure: a primary screen by flow cytometry of Nile red stained transformants grown in 96-deep-well plates under three sequential conditions (presence of nitrogen, then absence of nitrogen, followed by oil remobilization); a confirmation step using Nile red stained biological triplicates; and a validation step consisting of the quantification by thin layer chromatography of oil content of selected strains. Thirty-one mutants were isolated by screening 1,800 transformants generated by random insertional mutagenesis (1.7%). Five showed increased oil accumulation under the nitrogen-replete condition and 13 had altered oil content under nitrogen-depletion. All mutants were affected in oil remobilization. CONCLUSION This study demonstrates that various types of oil mutants can be isolated in Chlamydomonas based on the method set-up here, including mutants accumulating oil under optimal biomass growth. The strategy conceived and the protocol set-up should be applicable to other microalgal species such as Nannochloropsis and Chlorella, thus serving as a useful tool in Chlamydomonas oil research and algal biotechnology.
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Affiliation(s)
- Caroline Cagnon
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Boris Mirabella
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Hoa Mai Nguyen
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
- Present address: Institut des Sciences Moléculaires de Marseille, UMR 7313, Aix-Marseille Université, Marseille, France
| | - Audrey Beyly-Adriano
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Séverine Bouvet
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Stéphan Cuiné
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Fred Beisson
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Gilles Peltier
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
| | - Yonghua Li-Beisson
- CEA Cadarache, Institute of Environmental Biology and Biotechnology, Saint-Paul-lez-Durance F-13108, France
- CNRS, UMR7265, Saint-Paul-lez-Durance F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France
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177
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Metabolic engineering of lipid catabolism increases microalgal lipid accumulation without compromising growth. Proc Natl Acad Sci U S A 2013; 110:19748-53. [PMID: 24248374 DOI: 10.1073/pnas.1309299110] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biologically derived fuels are viable alternatives to traditional fossil fuels, and microalgae are a particularly promising source, but improvements are required throughout the production process to increase productivity and reduce cost. Metabolic engineering to increase yields of biofuel-relevant lipids in these organisms without compromising growth is an important aspect of advancing economic feasibility. We report that the targeted knockdown of a multifunctional lipase/phospholipase/acyltransferase increased lipid yields without affecting growth in the diatom Thalassiosira pseudonana. Antisense-expressing knockdown strains 1A6 and 1B1 exhibited wild-type-like growth and increased lipid content under both continuous light and alternating light/dark conditions. Strains 1A6 and 1B1, respectively, contained 2.4- and 3.3-fold higher lipid content than wild-type during exponential growth, and 4.1- and 3.2-fold higher lipid content than wild-type after 40 h of silicon starvation. Analyses of fatty acids, lipid classes, and membrane stability in the transgenic strains suggest a role for this enzyme in membrane lipid turnover and lipid homeostasis. These results demonstrate that targeted metabolic manipulations can be used to increase lipid accumulation in eukaryotic microalgae without compromising growth.
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178
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Blaby IK, Glaesener AG, Mettler T, Fitz-Gibbon ST, Gallaher SD, Liu B, Boyle NR, Kropat J, Stitt M, Johnson S, Benning C, Pellegrini M, Casero D, Merchant SS. Systems-level analysis of nitrogen starvation-induced modifications of carbon metabolism in a Chlamydomonas reinhardtii starchless mutant. THE PLANT CELL 2013; 25:4305-23. [PMID: 24280389 PMCID: PMC3875720 DOI: 10.1105/tpc.113.117580] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 10/08/2013] [Accepted: 10/31/2013] [Indexed: 05/17/2023]
Abstract
To understand the molecular basis underlying increased triacylglycerol (TAG) accumulation in starchless (sta) Chlamydomonas reinhardtii mutants, we undertook comparative time-course transcriptomics of strains CC-4348 (sta6 mutant), CC-4349, a cell wall-deficient (cw) strain purported to represent the parental STA6 strain, and three independent STA6 strains generated by complementation of sta6 (CC-4565/STA6-C2, CC-4566/STA6-C4, and CC-4567/STA6-C6) in the context of N deprivation. Despite N starvation-induced dramatic remodeling of the transcriptome, there were relatively few differences (5 × 10(2)) observed between sta6 and STA6, the most dramatic of which were increased abundance of transcripts encoding key regulated or rate-limiting steps in central carbon metabolism, specifically isocitrate lyase, malate synthase, transaldolase, fructose bisphosphatase and phosphoenolpyruvate carboxykinase (encoded by ICL1, MAS1, TAL1, FBP1, and PCK1 respectively), suggestive of increased carbon movement toward hexose-phosphate in sta6 by upregulation of the glyoxylate pathway and gluconeogenesis. Enzyme assays validated the increase in isocitrate lyase and malate synthase activities. Targeted metabolite analysis indicated increased succinate, malate, and Glc-6-P and decreased Fru-1,6-bisphosphate, illustrating the effect of these changes. Comparisons of independent data sets in multiple strains allowed the delineation of a sequence of events in the global N starvation response in C. reinhardtii, starting within minutes with the upregulation of alternative N assimilation routes and carbohydrate synthesis and subsequently a more gradual upregulation of genes encoding enzymes of TAG synthesis. Finally, genome resequencing analysis indicated that (1) the deletion in sta6 extends into the neighboring gene encoding respiratory burst oxidase, and (2) a commonly used STA6 strain (CC-4349) as well as the sequenced reference (CC-503) are not congenic with respect to sta6 (CC-4348), underscoring the importance of using complemented strains for more rigorous assignment of phenotype to genotype.
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Affiliation(s)
- Ian K. Blaby
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Anne G. Glaesener
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Tabea Mettler
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany 14476
| | - Sorel T. Fitz-Gibbon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
| | - Sean D. Gallaher
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Bensheng Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Nanette R. Boyle
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Janette Kropat
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Mark Stitt
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany 14476
| | - Shannon Johnson
- Genome Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Christoph Benning
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Matteo Pellegrini
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
- Institute of Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - David Casero
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
- Institute of Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Sabeeha S. Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
- Institute of Genomics and Proteomics, University of California, Los Angeles, California 90095
- Address correspondence to
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179
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Yu S, Zhao Q, Miao X, Shi J. Enhancement of lipid production in low-starch mutants Chlamydomonas reinhardtii by adaptive laboratory evolution. BIORESOURCE TECHNOLOGY 2013; 147:499-507. [PMID: 24012738 DOI: 10.1016/j.biortech.2013.08.069] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 08/08/2013] [Accepted: 08/10/2013] [Indexed: 05/09/2023]
Abstract
Adaptive laboratory evolution (ALE) is an effective method to improve microalgal strains. The growth phenotypes of three strains (cc4324, cc4326 and cc4334) of green microalgae Chlamydomonas reinhardtii were enhanced by ALE. As a result, endpoint strains exhibited higher growth rates. Upon the utilisation of ALE strategy, the biomass concentrations of the endpoint strains of cc4324, cc4326 and cc4334 became 1.17, 1.33 and 1.48 times of those of the starting strains. The total lipid content of the original strains was increased gradually from 32% to 36.67% in the endpoint strain cc4326 and abruptly increased from 24.27% to 44.67% in the endpoint strain cc4334 by nitrogen starvation. Slight growth impairment was also observed in low-starch mutants exposed to nitrogen starvation stress. However, this impairment was quickly resolved after nitrogen was replenished. These findings demonstrated that the biomass concentration and lipid productivity of low-starch mutants can be enhanced by ALE.
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Affiliation(s)
- Shuiyan Yu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 99 Haike Road, Shanghai 201210, China
| | - Quanyu Zhao
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 99 Haike Road, Shanghai 201210, China.
| | - Xiaoling Miao
- State Key Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Jiping Shi
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 99 Haike Road, Shanghai 201210, China
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Sun D, Zhu J, Fang L, Zhang X, Chow Y, Liu J. De novo transcriptome profiling uncovers a drastic downregulation of photosynthesis upon nitrogen deprivation in the nonmodel green alga Botryosphaerella sudeticus. BMC Genomics 2013; 14:715. [PMID: 24138407 PMCID: PMC4050207 DOI: 10.1186/1471-2164-14-715] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 10/07/2013] [Indexed: 11/30/2022] Open
Abstract
Background Neutral lipid storage is enhanced by nitrogen deprivation (ND) in numbers of green microalgal species. However, little is known about the metabolic pathways whose transcription levels are most significantly altered following ND in green microalgae, especially the nonmodel species. Results To start gaining knowledge on this, we performed transcriptome profiling of the nonmodel green microalga Botryosphaerella sudeticus cells in response to ND. Transcriptome of B. sudeticus is de novo assembled based on millions of HiSEQ short sequence reads using CLC Genomics Workbench software. The resulting non-redundant ESTs are annotated based on the best hits generated from the BLASTX homology comparison against the “best” proteins in the model microalgae Chlamydomonas reinhardtii and Chlorella variabilis. By using a pathway-based approach according to KEGG databases, we show that ESTs encoding ribosomal proteins and photosynthetic functions are the most abundantly expressed ESTs in the rapidly growing B. sudeticus cells. We find that ESTs encoding photosynthetic function but not the ribosomal proteins are most drastically downregulated upon ND. Notably, ESTs encoding lipid metabolic pathways are not significantly upregulated. Further analyses indicate that chlorophyll content is markedly decreased by 3-fold and total lipid content is only slightly increased by 50%, consistent with the transcriptional profiling. On the other hand, carbon content and photosynthesis efficiency are only marginally decreased by 7% and 20%, respectively, indicating that photosynthesis is only slightly reduced upon drastic downregulation of photosynthetic ESTs and chlorophyll content upon ND. In addition, TAG content is found to be greatly increased by 50-fold, though total lipid content is only slightly increased by 1.5-fold. Conclusions Taken together, our results suggest that light-harvesting proteins and chlorophylls are in excess in B. sudeticus. Degradation of excess photosynthesis proteins is most likely a mechanism for recycling of nitrogen-rich molecules to synthesize new proteins for preparation of gametogenesis and zygospore formation in adaptation and survival upon ND. Furthermore, our analyses indicate that TAG accumulation is largely attributed to the modification of other pre-existing lipid molecules, rather than de novo synthesis. We propose that this is likely an evolutionarily conserved mechanism in many green microalgae species. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-14-715) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Jianhua Liu
- Systems Biology, Genome Institute of Singapore, 60 Biopolis Street, #02-01, Singapore 138672, Singapore.
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181
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Kato N, Dong T, Bailey M, Lum T, Ingram D. Triacylglycerol mobilization is suppressed by brefeldin A in Chlamydomonas reinhardtii. PLANT & CELL PHYSIOLOGY 2013; 54:1585-99. [PMID: 23872273 PMCID: PMC4081630 DOI: 10.1093/pcp/pct103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Brefeldin A suppresses vesicle trafficking by inhibiting exchange of GDP for GTP in ADP-ribosylation factor. We report that brefeldin A suppresses mobilization of triacylglycerols in Chlamydomonas reinhardtii, a model organism of green microalgae. Analyses revealed that brefeldin A causes Chlamydomonas to form lipid droplets in which triacylglycerols accumulate in a dose-dependent manner. Pulse labeling experiment using fluorescent fatty acids suggested that brefeldin A inhibits the cells from degrading fatty acids. The experiment also revealed that the cells transiently form novel compartments that accumulate exogenously added fatty acids in the cytoplasm, designated fatty acid-induced microbodies (FAIMs). Brefeldin A up-regulates the formation of FAIMs, whereas nitrogen deprivation that up-regulates triacylglycerol synthesis in Chlamydomonas does not cause the cells to form FAIMs. These results underscore the role of the vesicle trafficking machinery in triacylglycerol metabolism in green microalgae.
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Affiliation(s)
- Naohiro Kato
- Department of Biological Sciences, Louisiana State University, 226 Life Sciences Building, Baton Rouge, LA 70803, USA
- *Corresponding author: E-mail: ; Fax: +1-225-578-2597
| | - Trung Dong
- Department of Biological Sciences, Louisiana State University, 226 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - Michael Bailey
- Department of Biological Sciences, Louisiana State University, 226 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - Tony Lum
- Department of Biological Sciences, Louisiana State University, 226 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - Drury Ingram
- Cell Biology & Bioimaging Core, Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, USA
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182
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Nguyen HM, Cuiné S, Beyly-Adriano A, Légeret B, Billon E, Auroy P, Beisson F, Peltier G, Li-Beisson Y. The green microalga Chlamydomonas reinhardtii has a single ω-3 fatty acid desaturase that localizes to the chloroplast and impacts both plastidic and extraplastidic membrane lipids. PLANT PHYSIOLOGY 2013; 163:914-28. [PMID: 23958863 PMCID: PMC3793068 DOI: 10.1104/pp.113.223941] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/16/2013] [Indexed: 05/03/2023]
Abstract
The ω-3 polyunsaturated fatty acids account for more than 50% of total fatty acids in the green microalga Chlamydomonas reinhardtii, where they are present in both plastidic and extraplastidic membranes. In an effort to elucidate the lipid desaturation pathways in this model alga, a mutant with more than 65% reduction in total ω-3 fatty acids was isolated by screening an insertional mutant library using gas chromatography-based analysis of total fatty acids of cell pellets. Molecular genetics analyses revealed the insertion of a TOC1 transposon 113 bp upstream of the ATG start codon of a putative ω-3 desaturase (CrFAD7; locus Cre01.g038600). Nuclear genetic complementation of crfad7 using genomic DNA containing CrFAD7 restored the wild-type fatty acid profile. Under standard growth conditions, the mutant is indistinguishable from the wild type except for the fatty acid difference, but when exposed to short-term heat stress, its photosynthesis activity is more thermotolerant than the wild type. A comparative lipidomic analysis of the crfad7 mutant and the wild type revealed reductions in all ω-3 fatty acid-containing plastidic and extraplastidic glycerolipid molecular species. CrFAD7 was localized to the plastid by immunofluorescence in situ hybridization. Transformation of the crfad7 plastidial genome with a codon-optimized CrFAD7 restored the ω-3 fatty acid content of both plastidic and extraplastidic lipids. These results show that CrFAD7 is the only ω-3 fatty acid desaturase expressed in C. reinhardtii, and we discuss possible mechanisms of how a plastid-located desaturase may impact the ω-3 fatty acid content of extraplastidic lipids.
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MESH Headings
- Adaptation, Physiological/genetics
- Adaptation, Physiological/radiation effects
- Amino Acid Sequence
- Cell Nucleus/genetics
- Chlamydomonas reinhardtii/enzymology
- Chlamydomonas reinhardtii/genetics
- Chlamydomonas reinhardtii/radiation effects
- Chloroplasts/enzymology
- Chloroplasts/genetics
- Chloroplasts/radiation effects
- DNA Transposable Elements/genetics
- DNA, Plant/genetics
- Fatty Acid Desaturases/chemistry
- Fatty Acid Desaturases/genetics
- Fatty Acid Desaturases/metabolism
- Fatty Acids, Omega-3/biosynthesis
- Fluorescent Antibody Technique
- Genetic Complementation Test
- Genetic Loci/genetics
- In Situ Hybridization
- Light
- Membrane Lipids/metabolism
- Microalgae/enzymology
- Microalgae/genetics
- Microalgae/radiation effects
- Models, Biological
- Molecular Sequence Data
- Mutagenesis, Insertional/genetics
- Mutation/genetics
- Promoter Regions, Genetic/genetics
- Sequence Homology, Nucleic Acid
- Subcellular Fractions/enzymology
- Temperature
- Transcription, Genetic/radiation effects
- Transformation, Genetic
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Affiliation(s)
- Hoa Mai Nguyen
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Stéphan Cuiné
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Audrey Beyly-Adriano
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Bertrand Légeret
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Emmanuelle Billon
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Pascaline Auroy
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Fred Beisson
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
| | - Gilles Peltier
- Commissariat à l’Energie Atomique Cadarache, Institut de Biologie Environnementale et Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
- CNRS, UMR Biologie Végétale et Microbiologie Environnementales, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.); and
- Aix-Marseille Université, Saint-Paul-lez-Durance F–13108, France (H.M.N., S.C., A.B.-A., B.L., E.B., P.A., F.B., G.P., Y.L.-B.)
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Havlik I, Reardon KF, Ünal M, Lindner P, Prediger A, Babitzky A, Beutel S, Scheper T. Monitoring of microalgal cultivations with on-line, flow-through microscopy. ALGAL RES 2013. [DOI: 10.1016/j.algal.2013.04.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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184
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Zheng M, Tian J, Yang G, Zheng L, Chen G, Chen J, Wang B. Transcriptome sequencing, annotation and expression analysis of Nannochloropsis sp. at different growth phases. Gene 2013; 523:117-21. [DOI: 10.1016/j.gene.2013.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/15/2013] [Accepted: 04/04/2013] [Indexed: 10/26/2022]
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185
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Abdelaziz AEM, Leite GB, Hallenbeck PC. Addressing the challenges for sustainable production of algal biofuels: II. Harvesting and conversion to biofuels. ENVIRONMENTAL TECHNOLOGY 2013; 34:1807-36. [PMID: 24350436 DOI: 10.1080/09593330.2013.831487] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In order to ensure the sustainability of algal biofuel production, a number of issues need to be addressed. Previously, we reviewed some of the questions in this area involving algal species and the important challenges of nutrient supply and how these might be met. Here, we take up issues involving harvesting and the conversion ofbiomass to biofuels. Advances in both these areas are required if these third-generation fuels are to have a sufficiently high net energy ratio and a sustainable footprint. A variety of harvesting technologies are under investigation and recent studies in this area are presented and discussed. A number of different energy uses are available for algal biomass, each with their own advantages as well as challenges in terms of efficiencies and yields. Recent advances in these areas are presented and some of the especially promising conversion processes are highlighted.
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Affiliation(s)
- Ahmed E M Abdelaziz
- Département de microbiologie et immunologie, Université de Montréal, CP 6128 Centre-Ville, Montréal, Quebec, Canada PQ H3C 3J7
| | - Gustavo B Leite
- Département de microbiologie et immunologie, Université de Montréal, CP 6128 Centre-Ville, Montréal, Quebec, Canada PQ H3C 3J7
| | - Patrick C Hallenbeck
- Département de microbiologie et immunologie, Université de Montréal, CP 6128 Centre-Ville, Montréal, Quebec, Canada PQ H3C 3J7
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186
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Voorhees KJ, Jensen KR, McAlpin CR, Rees JC, Cody R, Ubukata M, Cox CR. Modified MALDI MS fatty acid profiling for bacterial identification. JOURNAL OF MASS SPECTROMETRY : JMS 2013; 48:850-855. [PMID: 23832941 DOI: 10.1002/jms.3215] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/27/2013] [Accepted: 03/27/2013] [Indexed: 06/02/2023]
Abstract
Bacterial fatty acid profiling is a well-established technique for bacterial identification. Ten bacteria were analyzed using both positive- and negative-ion modes with a modified matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) approach using CaO as a matrix replacement (metal oxide laser ionization MS (MOLI MS)). The results show that reproducible lipid cleavage similar to thermal in situ tetramethyl ammonium hydroxide saponification/derivatization had occurred. Principal component analysis showed that replicates from each organism grouped in a unique space. Cross validation (CV) of spectra from both ionization modes resulted in greater than 94% validation of the data. When CV results were compared for the two ionization modes, negative-ion data produced a superior outcome. MOLI MS provides clinicians a rapid, reproducible and cost-effective bacterial diagnostic tool.
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Affiliation(s)
- Kent J Voorhees
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA.
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187
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Ortiz-Marquez JCF, Do Nascimento M, Zehr JP, Curatti L. Genetic engineering of multispecies microbial cell factories as an alternative for bioenergy production. Trends Biotechnol 2013; 31:521-9. [PMID: 23791304 DOI: 10.1016/j.tibtech.2013.05.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 01/01/2023]
Abstract
There is currently much interest in developing technology to use microlgae or cyanobacteria for the production of bioenergy and biomaterials. Here, we summarize some remarkable achievements in strains improvement by traditional genetic engineering and discuss common drawbacks for further progress. We present general knowledge on natural microalgal-bacterial mutualistic interactions and discuss the potential of recent developments in genetic engineering of multispecies microbial cell factories. This synthetic biology approach would rely on the assembly of complex metabolic networks from optimized metabolic modules such as photosynthetic or nitrogen-fixing parts.
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Affiliation(s)
- Juan Cesar Federico Ortiz-Marquez
- Instituto de Investigaciones en Biodiversidad y Biotecnología - Consejo Nacional de Investigaciones Científicas y Técnicas. Mar del Plata, Buenos Aires, Argentina
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188
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Dong HP, Williams E, Wang DZ, Xie ZX, Hsia RC, Jenck A, Halden R, Li J, Chen F, Place AR. Responses of Nannochloropsis oceanica IMET1 to Long-Term Nitrogen Starvation and Recovery. PLANT PHYSIOLOGY 2013; 162:1110-26. [PMID: 23637339 PMCID: PMC3668043 DOI: 10.1104/pp.113.214320] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/29/2013] [Indexed: 05/07/2023]
Abstract
The Nannochloropsis genus contains oleaginous microalgae that have served as model systems for developing renewable biodiesel. Recent genomic and transcriptomic studies on Nannochloropsis species have provided insights into the regulation of lipid production in response to nitrogen stress. Previous studies have focused on the responses of Nannochloropsis species to short-term nitrogen stress, but the effect of long-term nitrogen deprivation remains largely unknown. In this study, physiological and proteomic approaches were combined to understand the mechanisms by which Nannochloropsis oceanica IMET1 is able to endure long-term nitrate deprivation and its ability to recover homeostasis when nitrogen is amended. Changes of the proteome during chronic nitrogen starvation espoused the physiological changes observed, and there was a general trend toward recycling nitrogen and storage of lipids. This was evidenced by a global down-regulation of protein expression, a retained expression of proteins involved in glycolysis and the synthesis of fatty acids, as well as an up-regulation of enzymes used in nitrogen scavenging and protein turnover. Also, lipid accumulation and autophagy of plastids may play a key role in maintaining cell vitality. Following the addition of nitrogen, there were proteomic changes and metabolic changes observed within 24 h, which resulted in a return of the culture to steady state within 4 d. These results demonstrate the ability of N. oceanica IMET1 to recover from long periods of nitrate deprivation without apparent detriment to the culture and provide proteomic markers for genetic modification.
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Affiliation(s)
- Hong-Po Dong
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Ernest Williams
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Da-zhi Wang
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Zhang-Xian Xie
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Ru-ching Hsia
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Alizée Jenck
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Rolf Halden
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Jing Li
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
| | - Feng Chen
- Research Center for Harmful Algae and Marine Biology, Jinan University, Guangzhou 510632, China (H.-P.D.)
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, Maryland 21202 (H.-P.D., E.W., F.C., A.R.P.)
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen 361005, China (D.-z.W., Z.-X.X.)
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland 21202 (R.-c.H.)
- Center for Environmental Security Biodesign Institute/Security and Defense Systems Initiative, Arizona State University, Tempe, Arizona 85287 (A.J., R.H.); and
- CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and BioEnergy Genome Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China (J.L.)
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189
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Gimpel JA, Specht EA, Georgianna DR, Mayfield SP. Advances in microalgae engineering and synthetic biology applications for biofuel production. Curr Opin Chem Biol 2013; 17:489-95. [DOI: 10.1016/j.cbpa.2013.03.038] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/18/2013] [Accepted: 03/28/2013] [Indexed: 01/17/2023]
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190
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Velmurugan N, Sung M, Yim SS, Park MS, Yang JW, Jeong KJ. Evaluation of intracellular lipid bodies in Chlamydomonas reinhardtii strains by flow cytometry. BIORESOURCE TECHNOLOGY 2013; 138:30-7. [PMID: 23612159 DOI: 10.1016/j.biortech.2013.03.078] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/09/2013] [Accepted: 03/11/2013] [Indexed: 05/21/2023]
Abstract
A comparative study of Chlamydomonas reinhardtii wild type CC124 and a cell wall-less mutant sta6-1 is described using FACS in conjunction with two different lipophilic fluorescent dyes, Nile Red and BODIPY 505/515. The results indicate that BODIPY 505/515 is more effective for the vital staining of intracellular lipid bodies and single cell sorting than Nile Red. While BODIPY 505/515 stained cells continued to grow after single cell sorting using FACS, Nile Red stained cells failed to recover from sorting. In addition, a comprehensive study was performed to establish a quantitative baseline for future studies for either lipid accumulation and/or microalgal growth by measuring various parameters such as cell count, size, fatty acid contents/composition, and optical/confocal images of the wild type and mutant.
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Affiliation(s)
- Natarajan Velmurugan
- Department of Chemical and Biomolecular Engineering, KAIST, Yuseong-gu, Daejeon 305-701, Republic of Korea
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191
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Genetic manipulation, a feasible tool to enhance unique characteristic of Chlorella vulgaris as a feedstock for biodiesel production. Mol Biol Rep 2013; 40:4421-8. [DOI: 10.1007/s11033-013-2532-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 04/29/2013] [Indexed: 10/26/2022]
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192
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Lee SJ, Lee SJ, Lee DW. Design and development of synthetic microbial platform cells for bioenergy. Front Microbiol 2013; 4:92. [PMID: 23626588 PMCID: PMC3630320 DOI: 10.3389/fmicb.2013.00092] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/03/2013] [Indexed: 12/26/2022] Open
Abstract
The finite reservation of fossil fuels accelerates the necessity of development of renewable energy sources. Recent advances in synthetic biology encompassing systems biology and metabolic engineering enable us to engineer and/or create tailor made microorganisms to produce alternative biofuels for the future bio-era. For the efficient transformation of biomass to bioenergy, microbial cells need to be designed and engineered to maximize the performance of cellular metabolisms for the production of biofuels during energy flow. Toward this end, two different conceptual approaches have been applied for the development of platform cell factories: forward minimization and reverse engineering. From the context of naturally minimized genomes,non-essential energy-consuming pathways and/or related gene clusters could be progressively deleted to optimize cellular energy status for bioenergy production. Alternatively, incorporation of non-indigenous parts and/or modules including biomass-degrading enzymes, carbon uptake transporters, photosynthesis, CO2 fixation, and etc. into chassis microorganisms allows the platform cells to gain novel metabolic functions for bioenergy. This review focuses on the current progress in synthetic biology-aided pathway engineering in microbial cells and discusses its impact on the production of sustainable bioenergy.
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Affiliation(s)
- Sang Jun Lee
- Systems and Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology Daejeon, South Korea
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193
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Liang Y, Zhao X, Chi Z, Rover M, Johnston P, Brown R, Jarboe L, Wen Z. Utilization of acetic acid-rich pyrolytic bio-oil by microalga Chlamydomonas reinhardtii: reducing bio-oil toxicity and enhancing algal toxicity tolerance. BIORESOURCE TECHNOLOGY 2013; 133:500-506. [PMID: 23455221 DOI: 10.1016/j.biortech.2013.01.134] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 06/01/2023]
Abstract
This work was to utilize acetic acid contained in bio-oil for growth and lipid production of the microalga Chlamydomonas reinhardtii. The acetic acid-rich bio-oil fraction derived from fast pyrolysis of softwood contained 26% (w/w) acetic acid, formic acid, methanol, furfural, acetol, and phenolics as identified compounds, and 13% (w/w) unidentified compounds. Among those identified compounds, phenolics were most inhibitory to algal growth, followed by furfural and acetol. To enhance the fermentability of the bio-oil fraction, activated carbon was used to reduce the toxicity of the bio-oil, while metabolic evolution was used to enhance the toxicity tolerance of the microalgae. Combining activated carbon treatment and using evolved algal strain resulted in significant algal growth improvement. The results collectively showed that fast pyrolysis-fermentation process was a viable approach for converting biomass into fuels and chemicals.
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Affiliation(s)
- Yi Liang
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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194
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Liu B, Benning C. Lipid metabolism in microalgae distinguishes itself. Curr Opin Biotechnol 2013; 24:300-9. [DOI: 10.1016/j.copbio.2012.08.008] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 08/17/2012] [Accepted: 08/21/2012] [Indexed: 10/27/2022]
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195
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Central carbon metabolism and electron transport in Chlamydomonas reinhardtii: metabolic constraints for carbon partitioning between oil and starch. EUKARYOTIC CELL 2013; 12:776-93. [PMID: 23543671 DOI: 10.1128/ec.00318-12] [Citation(s) in RCA: 221] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The metabolism of microalgae is so flexible that it is not an easy task to give a comprehensive description of the interplay between the various metabolic pathways. There are, however, constraints that govern central carbon metabolism in Chlamydomonas reinhardtii that are revealed by the compartmentalization and regulation of the pathways and their relation to key cellular processes such as cell motility, division, carbon uptake and partitioning, external and internal rhythms, and nutrient stress. Both photosynthetic and mitochondrial electron transfer provide energy for metabolic processes and how energy transfer impacts metabolism and vice versa is a means of exploring the regulation and function of these pathways. A key example is the specific chloroplast localization of glycolysis/gluconeogenesis and how it impacts the redox poise and ATP budget of the plastid in the dark. To compare starch and lipids as carbon reserves, their value can be calculated in terms of NAD(P)H and ATP. As microalgae are now considered a potential renewable feedstock, we examine current work on the subject and also explore the possibility of rerouting metabolism toward lipid production.
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196
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Ramanan R, Kim BH, Cho DH, Ko SR, Oh HM, Kim HS. Lipid droplet synthesis is limited by acetate availability in starchless mutant of Chlamydomonas reinhardtii. FEBS Lett 2013; 587:370-7. [PMID: 23313852 DOI: 10.1016/j.febslet.2012.12.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/17/2012] [Accepted: 12/17/2012] [Indexed: 11/29/2022]
Abstract
Phenotypic and genotypic changes in Chlamydomonas reinhardtii BafJ5, a starchless mutant, with respect to lipid metabolism was studied in different trophic states under nitrogen (N) sufficient and limited conditions. Interestingly, cellular lipid content increased linearly with input acetate concentration with highest lipid content (∼42%) under nitrogen limitation and mixotrophic state. RT-qPCR studies indicate that key fatty acid biosynthesis genes are down-regulated under N limitation but not under mixotrophic state, whereas, ACS2, encoding Acetyl-CoA synthetase, and DGTT4, encoding Diacylglycerol O-acyltransferase, are up-regulated under all conditions. These results collectively indicate that acetate is the limiting factor and central molecule in lipid droplet synthesis. The study also provides further evidence of the presence of a chloroplast pathway for triacylglycerol synthesis in microalgae.
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Affiliation(s)
- Rishiram Ramanan
- Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea
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197
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New method for discovery of starch phenotypes in growing microalgal colonies. Anal Biochem 2013; 432:71-3. [DOI: 10.1016/j.ab.2012.09.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 11/18/2022]
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198
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Li X, Moellering ER, Liu B, Johnny C, Fedewa M, Sears BB, Kuo MH, Benning C. A galactoglycerolipid lipase is required for triacylglycerol accumulation and survival following nitrogen deprivation in Chlamydomonas reinhardtii. THE PLANT CELL 2012; 24:4670-86. [PMID: 23161887 PMCID: PMC3531859 DOI: 10.1105/tpc.112.105106] [Citation(s) in RCA: 212] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 10/16/2012] [Accepted: 10/27/2012] [Indexed: 05/17/2023]
Abstract
Following N deprivation, microalgae accumulate triacylglycerols (TAGs). To gain mechanistic insights into this phenomenon, we identified mutants with reduced TAG content following N deprivation in the model alga Chlamydomonas reinhardtii. In one of the mutants, the disruption of a galactoglycerolipid lipase-encoding gene, designated PLASTID GALACTOGLYCEROLIPID DEGRADATION1 (PGD1), was responsible for the primary phenotype: reduced TAG content, altered TAG composition, and reduced galactoglycerolipid turnover. The recombinant PGD1 protein, which was purified from Escherichia coli extracts, hydrolyzed monogalactosyldiacylglycerol into its lyso-lipid derivative. In vivo pulse-chase labeling identified galactoglycerolipid pools as a major source of fatty acids esterified in TAGs following N deprivation. Moreover, the fatty acid flux from plastid lipids to TAG was decreased in the pgd1 mutant. Apparently, de novo-synthesized fatty acids in Chlamydomonas reinhardtii are, at least partially, first incorporated into plastid lipids before they enter TAG synthesis. As a secondary effect, the pgd1 mutant exhibited a loss of viability following N deprivation, which could be avoided by blocking photosynthetic electron transport. Thus, the pgd1 mutant provides evidence for an important biological function of TAG synthesis following N deprivation, namely, relieving a detrimental overreduction of the photosynthetic electron transport chain.
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Affiliation(s)
- Xiaobo Li
- Department of Energy–Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Eric R. Moellering
- Department of Energy–Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Bensheng Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Cassandra Johnny
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Marie Fedewa
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Barbara B. Sears
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Min-Hao Kuo
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Christoph Benning
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
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199
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Molnár I, Lopez D, Wisecaver JH, Devarenne TP, Weiss TL, Pellegrini M, Hackett JD. Bio-crude transcriptomics: gene discovery and metabolic network reconstruction for the biosynthesis of the terpenome of the hydrocarbon oil-producing green alga, Botryococcus braunii race B (Showa). BMC Genomics 2012; 13:576. [PMID: 23110428 PMCID: PMC3533583 DOI: 10.1186/1471-2164-13-576] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 10/19/2012] [Indexed: 12/16/2022] Open
Abstract
Background Microalgae hold promise for yielding a biofuel feedstock that is sustainable, carbon-neutral, distributed, and only minimally disruptive for the production of food and feed by traditional agriculture. Amongst oleaginous eukaryotic algae, the B race of Botryococcus braunii is unique in that it produces large amounts of liquid hydrocarbons of terpenoid origin. These are comparable to fossil crude oil, and are sequestered outside the cells in a communal extracellular polymeric matrix material. Biosynthetic engineering of terpenoid bio-crude production requires identification of genes and reconstruction of metabolic pathways responsible for production of both hydrocarbons and other metabolites of the alga that compete for photosynthetic carbon and energy. Results A de novo assembly of 1,334,609 next-generation pyrosequencing reads form the Showa strain of the B race of B. braunii yielded a transcriptomic database of 46,422 contigs with an average length of 756 bp. Contigs were annotated with pathway, ontology, and protein domain identifiers. Manual curation allowed the reconstruction of pathways that produce terpenoid liquid hydrocarbons from primary metabolites, and pathways that divert photosynthetic carbon into tetraterpenoid carotenoids, diterpenoids, and the prenyl chains of meroterpenoid quinones and chlorophyll. Inventories of machine-assembled contigs are also presented for reconstructed pathways for the biosynthesis of competing storage compounds including triacylglycerol and starch. Regeneration of S-adenosylmethionine, and the extracellular localization of the hydrocarbon oils by active transport and possibly autophagy are also investigated. Conclusions The construction of an annotated transcriptomic database, publicly available in a web-based data depository and annotation tool, provides a foundation for metabolic pathway and network reconstruction, and facilitates further omics studies in the absence of a genome sequence for the Showa strain of B. braunii, race B. Further, the transcriptome database empowers future biosynthetic engineering approaches for strain improvement and the transfer of desirable traits to heterologous hosts.
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Affiliation(s)
- István Molnár
- Natural Products Center, School of Natural Resources and the Environment, The University of Arizona, Tucson, 85739, USA.
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200
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Elliott LG, Feehan C, Laurens LM, Pienkos PT, Darzins A, Posewitz MC. Establishment of a bioenergy-focused microalgal culture collection. ALGAL RES 2012. [DOI: 10.1016/j.algal.2012.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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