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Kobayashi K, Jimbo H, Nakamura Y, Wada H. Biosynthesis of phosphatidylglycerol in photosynthetic organisms. Prog Lipid Res 2024; 93:101266. [PMID: 38040200 DOI: 10.1016/j.plipres.2023.101266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/24/2023] [Accepted: 11/24/2023] [Indexed: 12/03/2023]
Abstract
Phosphatidylglycerol (PG) is a unique phospholipid class with its indispensable role in photosynthesis and growth in land plants, algae, and cyanobacteria. PG is the only major phospholipid in the thylakoid membrane of cyanobacteria and plant chloroplasts and a main lipid component in photosynthetic protein-cofactor complexes such as photosystem I and photosystem II. In plants and algae, PG is also essential as a substrate for the biosynthesis of cardiolipin, which is a unique lipid present only in mitochondrial membranes and crucial for the functions of mitochondria. PG biosynthesis pathways in plants include three membranous organelles, plastids, mitochondria, and the endoplasmic reticulum in a complex manner. While the molecular biology underlying the role of PG in photosynthetic functions is well established, many enzymes responsible for the PG biosynthesis are only recently cloned and functionally characterized in the model plant species including Arabidopsis thaliana and Chlamydomonas reinhardtii and cyanobacteria such as Synechocystis sp. PCC 6803. The characterization of those enzymes helps understand not only the metabolic flow for PG production but also the crosstalk of biosynthesis pathways between PG and other lipids. This review aims to summarize recent advances in the understanding of the PG biosynthesis pathway and functions of involved enzymes.
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Affiliation(s)
- Koichi Kobayashi
- Department of Biology, Graduate School of Science, Osaka Metropolitan University, Sakai, Japan.
| | - Haruhiko Jimbo
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuki Nakamura
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hajime Wada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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2
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Bolik S, Albrieux C, Schneck E, Demé B, Jouhet J. Sulfoquinovosyldiacylglycerol and phosphatidylglycerol bilayers share biophysical properties and are good mutual substitutes in photosynthetic membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184037. [PMID: 36041508 DOI: 10.1016/j.bbamem.2022.184037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/22/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Stéphanie Bolik
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France; Institut Laue-Langevin, 38000 Grenoble, France
| | - Catherine Albrieux
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, 64289 Darmstadt, Germany
| | - Bruno Demé
- Institut Laue-Langevin, 38000 Grenoble, France.
| | - Juliette Jouhet
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France.
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3
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Zhang Y, Ye Y, Bai F, Liu J. The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:119. [PMID: 33992124 PMCID: PMC8126118 DOI: 10.1186/s13068-021-01969-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/07/2021] [Indexed: 05/05/2023]
Abstract
The algal lipids-based biodiesel, albeit having advantages over plant oils, still remains high in the production cost. Co-production of value-added products with lipids has the potential to add benefits and is thus believed to be a promising strategy to improve the production economics of algal biodiesel. Chromochloris zofingiensis, a unicellular green alga, has been considered as a promising feedstock for biodiesel production because of its robust growth and ability of accumulating high levels of triacylglycerol under multiple trophic conditions. This alga is also able to synthesize high-value keto-carotenoids and has been cited as a candidate producer of astaxanthin, the strongest antioxidant found in nature. The concurrent accumulation of triacylglycerol and astaxanthin enables C. zofingiensis an ideal cell factory for integrated production of the two compounds and has potential to improve algae-based production economics. Furthermore, with the advent of chromosome-level whole genome sequence and genetic tools, C. zofingiensis becomes an emerging model for studying lipid metabolism and carotenogenesis. In this review, we summarize recent progress on the production of triacylglycerol and astaxanthin by C. zofingiensis. We also update our understanding in the distinctive molecular mechanisms underlying lipid metabolism and carotenogenesis, with an emphasis on triacylglycerol and astaxanthin biosynthesis and crosstalk between the two pathways. Furthermore, strategies for trait improvements are discussed regarding triacylglycerol and astaxanthin synthesis in C. zofingiensis.
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Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China.
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4
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Li-Beisson Y, Thelen JJ, Fedosejevs E, Harwood JL. The lipid biochemistry of eukaryotic algae. Prog Lipid Res 2019; 74:31-68. [PMID: 30703388 DOI: 10.1016/j.plipres.2019.01.003] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Algal lipid metabolism fascinates both scientists and entrepreneurs due to the large diversity of fatty acyl structures that algae produce. Algae have therefore long been studied as sources of genes for novel fatty acids; and, due to their superior biomass productivity, algae are also considered a potential feedstock for biofuels. However, a major issue in a commercially viable "algal oil-to-biofuel" industry is the high production cost, because most algal species only produce large amounts of oils after being exposed to stress conditions. Recent studies have therefore focused on the identification of factors involved in TAG metabolism, on the subcellular organization of lipid pathways, and on interactions between organelles. This has been accompanied by the development of genetic/genomic and synthetic biological tools not only for the reference green alga Chlamydomonas reinhardtii but also for Nannochloropsis spp. and Phaeodactylum tricornutum. Advances in our understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described herein with a focus on carbon and energetic aspects. We also summarize how changes in environmental factors can impact lipid metabolism and describe present and potential industrial uses of algal lipids.
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Affiliation(s)
- Yonghua Li-Beisson
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F-13108, France.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - Eric Fedosejevs
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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5
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Nakajima Y, Umena Y, Nagao R, Endo K, Kobayashi K, Akita F, Suga M, Wada H, Noguchi T, Shen JR. Thylakoid membrane lipid sulfoquinovosyl-diacylglycerol (SQDG) is required for full functioning of photosystem II in Thermosynechococcus elongatus. J Biol Chem 2018; 293:14786-14797. [PMID: 30076221 DOI: 10.1074/jbc.ra118.004304] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/09/2018] [Indexed: 02/04/2023] Open
Abstract
Sulfoquinovosyl-diacylglycerol (SQDG) is one of the four lipids present in the thylakoid membranes. Depletion of SQDG causes different degrees of effects on photosynthetic growth and activities in different organisms. Four SQDG molecules bind to each monomer of photosystem II (PSII), but their role in PSII function has not been characterized in detail, and no PSII structure without SQDG has been reported. We analyzed the activities of PSII from an SQDG-deficient mutant of the cyanobacterium Thermosynechococcus elongatus by various spectroscopic methods, which showed that depletion of SQDG partially impaired the PSII activity by impairing secondary quinone (QB) exchange at the acceptor site. We further solved the crystal structure of the PSII dimer from the SQDG deletion mutant at 2.1 Å resolution and found that all of the four SQDG-binding sites were occupied by other lipids, most likely PG molecules. Replacement of SQDG at a site near the head of QB provides a possible explanation for the QB impairment. The replacement of two SQDGs located at the monomer-monomer interface by other lipids decreased the stability of the PSII dimer, resulting in an increase in the amount of PSII monomer in the mutant. The present results thus suggest that although SQDG binding in all of the PSII-binding sites is necessary to fully maintain the activity and stability of PSII, replacement of SQDG by other lipids can partially compensate for their functions.
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Affiliation(s)
- Yoshiki Nakajima
- From the Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530
| | - Yasufumi Umena
- From the Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530
| | - Ryo Nagao
- From the Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530
| | - Kaichiro Endo
- the Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902
| | - Koichi Kobayashi
- the Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902
| | - Fusamichi Akita
- From the Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530.,the Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, and
| | - Michihiro Suga
- From the Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530
| | - Hajime Wada
- the Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902
| | - Takumi Noguchi
- the Division of Material Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Jian-Ren Shen
- From the Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530,
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Nagy V, Vidal-Meireles A, Podmaniczki A, Szentmihályi K, Rákhely G, Zsigmond L, Kovács L, Tóth SZ. The mechanism of photosystem-II inactivation during sulphur deprivation-induced H 2 production in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:548-561. [PMID: 29474754 DOI: 10.1111/tpj.13878] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 01/29/2018] [Accepted: 02/05/2018] [Indexed: 05/11/2023]
Abstract
Sulphur limitation may restrain cell growth and viability. In the green alga Chlamydomonas reinhardtii, sulphur limitation may induce H2 production lasting for several days, which can be exploited as a renewable energy source. Sulphur limitation causes a large number of physiological changes, including the inactivation of photosystem II (PSII), leading to the establishment of hypoxia, essential for the increase in hydrogenase expression and activity. The inactivation of PSII has long been assumed to be caused by the sulphur-limited turnover of its reaction center protein PsbA. Here we reinvestigated this issue in detail and show that: (i) upon transferring Chlamydomonas cells to sulphur-free media, the cellular sulphur content decreases only by about 25%; (ii) as demonstrated by lincomycin treatments, PsbA has a significant turnover, and other photosynthetic subunits, namely RbcL and CP43, are degraded more rapidly than PsbA. On the other hand, sulphur limitation imposes oxidative stress early on, most probably involving the formation of singlet oxygen in PSII, which leads to an increase in the expression of GDP-L-galactose phosphorylase, playing an essential role in ascorbate biosynthesis. When accumulated to the millimolar concentration range, ascorbate may inactivate the oxygen-evolving complex and provide electrons to PSII, albeit at a low rate. In the absence of a functional donor side and sufficient electron transport, PSII reaction centers are inactivated and degraded. We therefore demonstrate that the inactivation of PSII is a complex and multistep process, which may serve to mitigate the damaging effects of sulphur limitation.
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Affiliation(s)
- Valéria Nagy
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - André Vidal-Meireles
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Anna Podmaniczki
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Klára Szentmihályi
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences Hungarian Academy of Sciences, Budapest, Hungary
| | - Gábor Rákhely
- Department of Biotechnology, University of Szeged, Szeged, Hungary
| | - Laura Zsigmond
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Szilvia Z Tóth
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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Carfagna S, Bottone C, Cataletto PR, Petriccione M, Pinto G, Salbitani G, Vona V, Pollio A, Ciniglia C. Impact of Sulfur Starvation in Autotrophic and Heterotrophic Cultures of the Extremophilic Microalga Galdieria phlegrea (Cyanidiophyceae). PLANT & CELL PHYSIOLOGY 2016; 57:1890-8. [PMID: 27388343 DOI: 10.1093/pcp/pcw112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 06/03/2016] [Indexed: 05/18/2023]
Abstract
In plants and algae, sulfate assimilation and cysteine synthesis are regulated by sulfur (S) accessibility from the environment. This study reports the effects of S deprivation in autotrophic and heterotrophic cultures of Galdieria phlegrea (Cyanidiophyceae), a unicellular red alga isolated in the Solfatara crater located in Campi Flegrei (Naples, Italy), where H2S is the prevalent form of gaseous S in the fumarolic fluids and S is widespread in the soils near the fumaroles. This is the first report on the effects of S deprivation on a sulfurous microalga that is also able to grow heterotrophically in the dark. The removal of S from the culture medium of illuminated cells caused a decrease in the soluble protein content and a significant decrease in the intracellular levels of glutathione. Cells from heterotrophic cultures of G. phlegrea exhibited high levels of internal proteins and high glutathione content, which did not diminish during S starvation, but rather glutathione significantly increased. The activity of O-acetylserine(thiol)lyase (OASTL), the enzyme synthesizing cysteine, was enhanced under S deprivation in a time-dependent manner in autotrophic but not in heterotrophic cells. Analysis of the transcript abundance of the OASTL gene supports the OASTL activity increase in autotrophic cultures under S deprivation.
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Affiliation(s)
- Simona Carfagna
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Claudia Bottone
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Pia Rosa Cataletto
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Milena Petriccione
- Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Unità di ricerca per la Frutticoltura, Via Torrino 2, I-81100 Caserta, Italy
| | - Gabriele Pinto
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Giovanna Salbitani
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Vincenza Vona
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Antonino Pollio
- Department of Biology, University of Naples Federico II, Via Foria 223, I-80139 Naples, Italy
| | - Claudia Ciniglia
- Department of Biological and Pharmaceutical Science and Technology, Second University of Naples, Via Vivaldi 43, I-81100 Caserta, Italy
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Effects of carbon source and light intensity on the growth and total lipid production of three microalgae under different culture conditions. ACTA ACUST UNITED AC 2016; 43:605-16. [DOI: 10.1007/s10295-016-1741-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
Abstract
Abstract
We attempted to enhance the growth and total lipid production of three microalgal species, Isochrysis galbana LB987, Nannochloropsis oculata CCAP849/1, and Dunaliella salina, which are capable of accumulating high content of lipid in cells. Low nitrogen concentration under photoautotrophic conditions stimulated total lipid production, but a decreasing total lipid content and an increasing biomass were observed with increasing nitrogen concentration. Among the different carbon sources tested for heterotrophic cultivation, glucose improved the growth of all three strains. The optimal glucose concentration for growth of I. galbana LB987 and N. oculata CCAP849/1 was 0.02 M, and that of D. salina was 0.05 M. Enhanced growth occurred when they were cultivated under heterotrophic or mixotrophic conditions compared with photoautotrophic conditions. Meanwhile, high total lipid accumulation in cells occurred when they were cultivated under photoautotrophic or mixotrophic conditions. During mixotrophic cultivation, biomass production was not affected significantly by light intensity; however, both chlorophyll concentration and total lipid content increased dramatically with increasing light intensity up to 150 µmol/m2/s. The amount and composition ratio of saturated and unsaturated fatty acids in cells were different from each other depending on both species and light intensity. The highest accumulation of total fatty acid (C16–C18) among the three strains was found from cells of N. oculata CCAP849/1, which indicates that this species can be used as a source for production of biodiesel.
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Abstract
In response to demands for sustainable domestic fuel sources, research into biofuels has become increasingly important. Many challenges face biofuels in their effort to replace petroleum fuels, but rational strain engineering of algae and photosynthetic organisms offers a great deal of promise. For decades, mutations and stress responses in photosynthetic microbiota were seen to result in production of exciting high-energy fuel molecules, giving hope but minor capability for design. However, '-omics' techniques for visualizing entire cell processing has clarified biosynthesis and regulatory networks. Investigation into the promising production behaviors of the model organism C. reinhardtii and its mutants with these powerful techniques has improved predictability and understanding of the diverse, complex interactions within photosynthetic organisms. This new equipment has created an exciting new frontier for high-throughput, predictable engineering of photosynthetically produced carbon-neutral biofuels.
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Affiliation(s)
- Hanna R Aucoin
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, 80401, USA
| | - Joseph Gardner
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, 80401, USA
| | - Nanette R Boyle
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, 80401, USA.
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10
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Yang D, Song D, Kind T, Ma Y, Hoefkens J, Fiehn O. Lipidomic Analysis of Chlamydomonas reinhardtii under Nitrogen and Sulfur Deprivation. PLoS One 2015; 10:e0137948. [PMID: 26375463 PMCID: PMC4574153 DOI: 10.1371/journal.pone.0137948] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 08/24/2015] [Indexed: 12/21/2022] Open
Abstract
Chlamydomonas reinhardtii accumulates lipids under complete nutrient starvation conditions while overall growth in biomass stops. In order to better understand biochemical changes under nutrient deprivation that maintain production of algal biomass, we used a lipidomic assay for analyzing the temporal regulation of the composition of complex lipids in C. reinhardtii in response to nitrogen and sulfur deprivation. Using a chip-based nanoelectrospray direct infusion into an ion trap mass spectrometer, we measured a diversity of lipid species reported for C. reinhardtii, including PG phosphatidylglycerols, PI Phosphatidylinositols, MGDG monogalactosyldiacylglycerols, DGDG digalactosyldiacylglycerols, SQDG sulfoquinovosyldiacylglycerols, DGTS homoserine ether lipids and TAG triacylglycerols. Individual lipid species were annotated by matching mass precursors and MS/MS fragmentations to the in-house LipidBlast mass spectral database and MS2Analyzer. Multivariate statistics showed a clear impact on overall lipidomic phenotypes on both the temporal and the nutrition stress level. Homoserine-lipids were found up-regulated at late growth time points and higher cell density, while triacyclglycerols showed opposite regulation of unsaturated and saturated fatty acyl chains under nutritional deprivation.
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Affiliation(s)
- Dawei Yang
- Zhong Yuan Academy of Biological Medicine, Liaocheng People's Hospital/Affiliated Liaocheng Hospital, Taishan Medical University, 67 Dong Chang Xi Lu, Liaocheng, Shandong, 252000, P. R. China
| | - Donghui Song
- Department of Marine Science, College of Marine Science & Engineering, Tianjin University of Science & Technology 29, the 13th St., TEDA, Tianjin, 300457, P. R. China
| | - Tobias Kind
- UC Davis Genome Center- Metabolomics, Davis, California 95616, United States of America
| | - Yan Ma
- UC Davis Genome Center- Metabolomics, Davis, California 95616, United States of America
| | - Jens Hoefkens
- Genedata Inc, Waltham, Massachusetts, United States of America
| | - Oliver Fiehn
- UC Davis Genome Center- Metabolomics, Davis, California 95616, United States of America
- King Abdulaziz University, Faculty of Science, Biochemistry Department, PO Box 80203, Jeddah 21589, Saudi Arabia
- * E-mail:
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11
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Sawyer AL, Hankamer BD, Ross IL. Sulphur responsiveness of the Chlamydomonas reinhardtii LHCBM9 promoter. PLANTA 2015; 241:1287-1302. [PMID: 25672503 DOI: 10.1007/s00425-015-2249-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/17/2015] [Indexed: 06/04/2023]
Abstract
A 44-base-pair region in the Chlamydomonas reinhardtii LHCBM9 promoter is essential for sulphur responsiveness. The photosynthetic light-harvesting complex (LHC) proteins play essential roles both in light capture, the first step of photosynthesis, and in photoprotective mechanisms. In contrast to the other LHC proteins and the majority of photosynthesis proteins, the Chlamydomonas reinhardtii photosystem II-associated LHC protein, LHCBM9, was recently reported to be up-regulated under sulphur deprivation conditions, which also induce hydrogen production. Here, we examined the sulphur responsiveness of the LHCBM9 gene at the transcriptional level, through promoter deletion analysis. The LHCBM9 promoter was found to be responsive to sulphur deprivation, with a 44-base-pair region between nucleotide positions -136 and -180 relative to the translation start site identified as essential for this response. Anaerobiosis was found to enhance promoter activity under sulphur deprivation conditions, however, alone was unable to induce promoter activity. The study of LHCBM9 is of biological and biotechnological importance, as its expression is linked to photobiological hydrogen production, theoretically the most efficient process for biofuel production, while the simplicity of using an S-deprivation trigger enables the development of a novel C. reinhardtii-inducible promoter system based on LHCBM9.
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Affiliation(s)
- Anne L Sawyer
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
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12
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Martin GJO, Hill DRA, Olmstead ILD, Bergamin A, Shears MJ, Dias DA, Kentish SE, Scales PJ, Botté CY, Callahan DL. Lipid profile remodeling in response to nitrogen deprivation in the microalgae Chlorella sp. (Trebouxiophyceae) and Nannochloropsis sp. (Eustigmatophyceae). PLoS One 2014; 9:e103389. [PMID: 25171084 PMCID: PMC4149361 DOI: 10.1371/journal.pone.0103389] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 06/29/2014] [Indexed: 12/29/2022] Open
Abstract
Many species of microalgae produce greatly enhanced amounts of triacylglycerides (TAGs), the key product for biodiesel production, in response to specific environmental stresses. Improvement of TAG production by microalgae through optimization of growth regimes is of great interest. This relies on understanding microalgal lipid metabolism in relation to stress response in particular the deprivation of nutrients that can induce enhanced TAG synthesis. In this study, a detailed investigation of changes in lipid composition in Chlorella sp. and Nannochloropsis sp. in response to nitrogen deprivation (N-deprivation) was performed to provide novel mechanistic insights into the lipidome during stress. As expected, an increase in TAGs and an overall decrease in polar lipids were observed. However, while most membrane lipid classes (phosphoglycerolipids and glycolipids) were found to decrease, the non-nitrogen containing phosphatidylglycerol levels increased considerably in both algae from initially low levels. Of particular significance, it was observed that the acyl composition of TAGs in Nannochloropsis sp. remain relatively constant, whereas Chlorella sp. showed greater variability following N-deprivation. In both algae the overall fatty acid profiles of the polar lipid classes were largely unaffected by N-deprivation, suggesting a specific FA profile for each compartment is maintained to enable continued function despite considerable reductions in the amount of these lipids. The changes observed in the overall fatty acid profile were due primarily to the decrease in proportion of polar lipids to TAGs. This study provides the most detailed lipidomic information on two different microalgae with utility in biodiesel production and nutraceutical industries and proposes the mechanisms for this rearrangement. This research also highlights the usefulness of the latest MS-based approaches for microalgae lipid research.
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Affiliation(s)
- Gregory J. O. Martin
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - David R. A. Hill
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Ian L. D. Olmstead
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Amanda Bergamin
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Melanie J. Shears
- Metabolomics Australia, The School of Botany, The University of Melbourne, Parkville, Victoria, Australia
- Apicolipid Group, Laboratoire Adaption et Pathogenie des Microorganismes UMR5163, CNRS, University of Grenoble I, La Tronche, France
| | - Daniel A. Dias
- Metabolomics Australia, The School of Botany, The University of Melbourne, Parkville, Victoria, Australia
| | - Sandra E. Kentish
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Peter J. Scales
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Cyrille Y. Botté
- Apicolipid Group, Laboratoire Adaption et Pathogenie des Microorganismes UMR5163, CNRS, University of Grenoble I, La Tronche, France
- * E-mail:
| | - Damien L. Callahan
- Metabolomics Australia, The School of Botany, The University of Melbourne, Parkville, Victoria, Australia
- Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
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Lukeš M, Procházková L, Shmidt V, Nedbalová L, Kaftan D. Temperature dependence of photosynthesis and thylakoid lipid composition in the red snow alga Chlamydomonas cf. nivalis (Chlorophyceae). FEMS Microbiol Ecol 2014; 89:303-15. [PMID: 24698015 DOI: 10.1111/1574-6941.12299] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 02/04/2014] [Accepted: 02/04/2014] [Indexed: 11/28/2022] Open
Abstract
Here, we report an effect of short acclimation to a wide span of temperatures on photosynthetic electron transfer, lipid and fatty acid composition in the snow alga Chlamydomonas cf. nivalis. The growth and oxygen evolution capacity were low at 2 °C yet progressively enhanced at 10 °C and were significantly higher at temperatures from 5 to 15 °C in comparison with the mesophilic control Chlamydomonas reinhardtii. In search of the molecular mechanisms responsible for the adaptation of photosynthesis to low temperatures, we have found unprecedented high rates of QA to QB electron transfer. The thermodynamics of the process revealed the existence of an increased structural flexibility that we explain with the amino acid changes in the D1 protein combined with the physico-chemical characteristics of the thylakoid membrane composed of > 80% negatively charged phosphatidylglycerol.
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Affiliation(s)
- Martin Lukeš
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic; Department of Phototrophic Microorganisms, Institute of Microbiology CAS, Opatovický mlýn, Třeboň, Czech Republic
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14
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Sato A, Matsumura R, Hoshino N, Tsuzuki M, Sato N. Responsibility of regulatory gene expression and repressed protein synthesis for triacylglycerol accumulation on sulfur-starvation in Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2014; 5:444. [PMID: 25309550 PMCID: PMC4160968 DOI: 10.3389/fpls.2014.00444] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 08/18/2014] [Indexed: 05/20/2023]
Abstract
Triacylglycerol (TG) synthesis is induced for energy and carbon storage in algal cells under nitrogen(N)-starved conditions, and helps prevent reactive oxygen species (ROS) production through fatty acid synthesis that consumes excessive reducing power. Here, the regulatory mechanism for the TG content in sulfur(S)-starved cells of Chlamydomonas reinhardtii was examined, in comparison to that in N- or phosphorus(P)-starved cells. S- and N- starved cells exhibited markedly increased TG contents with up-regulation of mRNA levels of diacylglycerol acyltransferase (DGAT) genes. S-Starvation also induced expression of the genes for phosphatidate synthesis. In contrast, P-starved cells exhibited little alteration of the TG content with almost no induction of these genes. The results implied deficient nutrient-specific regulation of the TG content. An arg9 disruptant defective in arginine synthesis, even without nutritional deficiencies, exhibited an increased TG content upon removal of supplemented arginine, which repressed protein synthesis. Repression of protein synthesis thus seemed crucial for TG accumulation in S- or N- starved cells. Meanwhile, the results of inhibitor experiments involving cells inferred that TG accumulation during S-starvation is supported by photosynthesis and de novo fatty acid synthesis. During S-starvation, sac1 and snrk2.2 disruptants, which are defective in the response to the ambient S-status, accumulated TG at lower and higher levels, respectively, than the wild type. The sac1 and snrk2.2 disruptants showed no or much greater up-regulation of DGAT genes, respectively. In conclusion, TG synthesis would be activated in S-starved cells, through the diversion of metabolic carbon-flow from protein to TG synthesis, and simultaneously through up-regulation of the expression of a particular set of genes for TG synthesis at proper levels through the actions of SAC1 and SNRK2.2.
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Affiliation(s)
- Atsushi Sato
- School of Life Sciences, Tokyo University of Pharmacy and Life SciencesHachioji, Japan
- Japan Science and Technology Agency, Core Research for Evolutionary Science and TechnologyChiyoda-ku, Japan
| | - Rie Matsumura
- School of Life Sciences, Tokyo University of Pharmacy and Life SciencesHachioji, Japan
| | - Naomi Hoshino
- School of Life Sciences, Tokyo University of Pharmacy and Life SciencesHachioji, Japan
| | - Mikio Tsuzuki
- School of Life Sciences, Tokyo University of Pharmacy and Life SciencesHachioji, Japan
- Japan Science and Technology Agency, Core Research for Evolutionary Science and TechnologyChiyoda-ku, Japan
| | - Norihiro Sato
- School of Life Sciences, Tokyo University of Pharmacy and Life SciencesHachioji, Japan
- Japan Science and Technology Agency, Core Research for Evolutionary Science and TechnologyChiyoda-ku, Japan
- *Correspondence: Norihiro Sato, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo 192-0392, Japan e-mail:
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15
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Mus F, Toussaint JP, Cooksey KE, Fields MW, Gerlach R, Peyton BM, Carlson RP. Physiological and molecular analysis of carbon source supplementation and pH stress-induced lipid accumulation in the marine diatom Phaeodactylum tricornutum. Appl Microbiol Biotechnol 2013; 97:3625-42. [DOI: 10.1007/s00253-013-4747-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 01/19/2013] [Accepted: 01/31/2013] [Indexed: 11/30/2022]
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16
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La Russa M, Bogen C, Uhmeyer A, Doebbe A, Filippone E, Kruse O, Mussgnug JH. Functional analysis of three type-2 DGAT homologue genes for triacylglycerol production in the green microalga Chlamydomonas reinhardtii. J Biotechnol 2012; 162:13-20. [PMID: 22542934 DOI: 10.1016/j.jbiotec.2012.04.006] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/03/2012] [Accepted: 04/10/2012] [Indexed: 01/10/2023]
Abstract
Photosynthetic organisms like plants and algae can use sunlight to produce lipids as important metabolic compounds. Plant-derived triacylglycerols (TAGs) are valuable for human and animal nutrition because of their high energy content and are becoming increasingly important for the production of renewable biofuels. Acyl-CoA:diacylglycerol acyltransferases (DGATs) have been demonstrated to play an important role in the accumulation of TAG compounds in higher plants. DGAT homologue genes have been identified in the genome of the green alga Chlamydomonas reinhardtii, however their function in vivo is still unknown. In this work, the three most promising type-2 DGAT candidate genes potentially involved in TAG lipid accumulation (CrDGAT2a, b and c) were investigated by constructing overexpression strains. For each of the genes, three strains were identified which showed enhanced mRNA levels of between 1.7 and 29.1 times that of the wild type (wt). Total lipid contents, neutral lipids and fatty acid profiles were determined and showed that an enhanced mRNA expression level of the investigated DGAT genes did not boost the intracellular TAG accumulation or resulted in alterations of the fatty acid profiles compared to wild type during standard growth condition or during nitrogen or sulfur stress conditions. We conclude that biotechnological efforts to enhance cellular TAG amount in microalgae need further insights into the complex network of lipid biosynthesis to identify potential bottlenecks of neutral lipid production.
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Affiliation(s)
- M La Russa
- Algae Biotechnology & Bioenergy, Department of Biology, Center for Biotechnology-CeBiTec, Bielefeld University, 33615 Bielefeld, Germany
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17
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Isolation and partial characterization of mutants with elevated lipid content in Chlorella sorokiniana and Scenedesmus obliquus. J Biotechnol 2012; 162:3-12. [PMID: 22480533 DOI: 10.1016/j.jbiotec.2012.03.017] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/16/2012] [Accepted: 03/20/2012] [Indexed: 01/10/2023]
Abstract
This paper describes the isolation and partial biomass characterization of high triacylglycerol (TAG) mutants of Chlorella sorokiniana and Scenedesmus obliquus, two algal species considered as potential source of biodiesel. Following UV mutagenesis, 2000 Chlorella and 2800 Scenedesmus colonies were screened with a method based on Nile Red fluorescence. Several mutants with high Nile Red fluorescence were selected by this high-throughput method in both species. Growth and biomass parameters of the strongest mutants were analyzed in detail. All of the four Chlorella mutants showed no significant changes in growth rate, cell weight, cell size, protein and chlorophyll contents on a per cell basis. Whereas all contained elevated total lipid and TAG content per unit of dry weight, two of them were also affected for starch metabolism, suggesting a change in biomass/storage carbohydrate composition. Two Scenedesmus mutants showed a 1.5 and 2-fold increased cell weight and larger cells compared to the wild type, which led to a general increase of biomass including total lipid and TAG content on a per cell basis. Such mutants could subsequently be used as commercial oleaginous algae and serve as an alternative to conventional petrol.
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18
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Falvo S, Di Carli M, Desiderio A, Benvenuto E, Moglia A, America T, Lanteri S, Acquadro A. 2-D DIGE analysis of UV-C radiation-responsive proteins in globe artichoke leaves. Proteomics 2012; 12:448-60. [PMID: 22162389 DOI: 10.1002/pmic.201100337] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 11/22/2011] [Accepted: 11/24/2011] [Indexed: 01/08/2023]
Abstract
Plants respond to ultraviolet stress inducing a self-defence through the regulation of specific gene family members. The UV acclimation is the result of biochemical and physiological processes, such as enhancement of the antioxidant enzymatic system and accumulation of UV-absorbing phenolic compounds (e.g. flavonoids). Globe artichoke is an attractive species for studying the protein network involved in UV stress response, being characterized by remarkable levels of inducible antioxidants. Proteomic tools can assist the evaluation of the expression patterns of UV-responsive proteins and we applied the difference in-gel electrophoresis (DIGE) technology for monitoring the globe artichoke proteome variation at four time points following an acute UV-C exposure. A total of 145 UV-C-modulated proteins were observed and 119 were identified by LC-MS/MS using a ∼144,000 customized Compositae protein database, which included about 19,000 globe artichoke unigenes. Proteins were Gene Ontology (GO) categorized, visualized on their pathways and their behaviour was discussed. A predicted protein interaction network was produced and highly connected hub-like proteins were highlighted. Most of the proteins differentially modulated were chloroplast located, involved in photosynthesis, sugar metabolisms, protein folding and abiotic stress. The identification of UV-C-responsive proteins may contribute to shed light on the molecular mechanisms underlying plant responses to UV stress.
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Affiliation(s)
- Sara Falvo
- DIVAPRA, University of Turin, Grugliasco, Torino, Italy
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19
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Trachydiscus minutus, a new biotechnological source of eicosapentaenoic acid. Folia Microbiol (Praha) 2010; 55:265-9. [DOI: 10.1007/s12223-010-0039-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 04/14/2010] [Indexed: 10/19/2022]
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20
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Sugimoto K, Tsuzuki M, Sato N. Regulation of synthesis and degradation of a sulfolipid under sulfur-starved conditions and its physiological significance in Chlamydomonas reinhardtii. THE NEW PHYTOLOGIST 2010; 185:676-86. [PMID: 20003074 DOI: 10.1111/j.1469-8137.2009.03115.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Regulation of synthesis and degradation of sulfoquinovosyl diacylglycerol (SQDG), one of the membrane lipids that construct thylakoids, under sulfur (S)-starved conditions and its physiological significance were explored in a green alga, Chlamydomonas reinhardtii. Here, we used sac1 and sac3 mutants defective in response to ambient S-status to characterize the system of known induction of SQDG degradation by S starvation that ensures a major S source for protein synthesis. The SQDG synthesis system was monitored in the wild type during S starvation. An SQDG-deficient mutant, hf-2, was utilized to discover functions where SQDG metabolism participates during S starvation. The induction of SQDG degradation was largely repressed in both sac1 and sac3 mutants. The SQDG synthesis capacity was increased by 40% after S starvation, with a sixfold elevation in the mRNA level of the SQD1 gene for SQDG synthesis. Compared with the wild type, hf-2 had decreased protein accumulation, photosystem (PS) I stability and growth rate. A role of SQDG as an S storage lipid is fulfilled under the control of both SAC1 and SAC3 genes, and it is essential for proper protein synthesis in acclimatization of cells to S starvation. The enhancement in SQDG synthesis may reflect the importance of SQDG as the membrane lipid that stabilizes the PSI complex.
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Affiliation(s)
- Koichi Sugimoto
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi, Hachioji, Tokyo 192-0392, Japan
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21
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Bogos B, Ughy B, Domonkos I, Laczkó-Dobos H, Komenda J, Abasova L, Cser K, Vass I, Sallai A, Wada H, Gombos Z. Phosphatidylglycerol depletion affects photosystem II activity in Synechococcus sp. PCC 7942 cells. PHOTOSYNTHESIS RESEARCH 2010; 103:19-30. [PMID: 19763873 DOI: 10.1007/s11120-009-9497-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 09/03/2009] [Indexed: 05/28/2023]
Abstract
The role of phosphatidylglycerol (PG) in photosynthetic membranes of cyanobacteria was analyzed in a Synechococcus sp. PCC 7942 mutant produced by inactivating its cdsA gene presumably encoding cytidine 5'-diphosphate-diacylglycerol synthase, a key enzyme in PG synthesis. In a medium supplemented with PG the Synechococcus sp. PCC 7942/DeltacdsA cells grew photoautotrophically. Depletion of PG in the medium resulted (a) in an arrest of cell growth and division, (b) in a suppression of O(2) evolving activity, and (c) in a modification of Chl fluorescence induction curves. Two-dimensional PAGE showed that in the absence of PG (a) the amount of the PSI monomers increased at the expense of the PSI trimers and (b) PSII dimers were decomposed into monomers. [(35)S]methionine labeling confirmed that PG depletion did not block the de novo synthesis of PSII proteins but slowed down the assembly of the newly synthesized D1 protein into PSII core complexes. Retailoring of PG was observed during PG depletion: the exogenously added artificial dioleoyl PG was transformed into photosynthetically more essential PG derivatives. Concomitantly with a decrease in PG content, SQDG content increased, but it could not restore photosynthetic activity.
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Affiliation(s)
- Balázs Bogos
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P. O. Box 521, 6701 Szeged, Hungary
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Dangate M, Franchini L, Ronchetti F, Arai T, Iida A, Tokuda H, Colombo D. 2-O-β-d-Glucopyranosyl-sn-glycerol based analogues of sulfoquinovosyldiacylglycerols (SQDG) and their role in inhibiting Epstein-Barr virus early antigen activation. Bioorg Med Chem 2009; 17:5968-73. [DOI: 10.1016/j.bmc.2009.06.064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/24/2009] [Accepted: 06/28/2009] [Indexed: 10/20/2022]
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23
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Beer LL, Boyd ES, Peters JW, Posewitz MC. Engineering algae for biohydrogen and biofuel production. Curr Opin Biotechnol 2009; 20:264-71. [DOI: 10.1016/j.copbio.2009.06.002] [Citation(s) in RCA: 230] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 06/02/2009] [Accepted: 06/03/2009] [Indexed: 01/11/2023]
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24
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Moseley JL, Gonzalez-Ballester D, Pootakham W, Bailey S, Grossman AR. Genetic interactions between regulators of Chlamydomonas phosphorus and sulfur deprivation responses. Genetics 2009; 181:889-905. [PMID: 19087952 PMCID: PMC2651062 DOI: 10.1534/genetics.108.099382] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 12/14/2008] [Indexed: 02/06/2023] Open
Abstract
The Chlamydomonas reinhardtii PSR1 gene is required for proper acclimation of the cells to phosphorus (P) deficiency. P-starved psr1 mutants show signs of secondary sulfur (S) starvation, exemplified by the synthesis of extracellular arylsulfatase and the accumulation of transcripts encoding proteins involved in S scavenging and assimilation. Epistasis analysis reveals that induction of the S-starvation responses in P-limited psr1 cells requires the regulatory protein kinase SNRK2.1, but bypasses the membrane-targeted activator, SAC1. The inhibitory kinase SNRK2.2 is necessary for repression of S-starvation responses during both nutrient-replete growth and P limitation; arylsulfatase activity and S deficiency-responsive genes are partially induced in the P-deficient snrk2.2 mutants and become fully activated in the P-deficient psr1snrk2.2 double mutant. During P starvation, the sac1snrk2.2 double mutants or the psr1sac1snrk2.2 triple mutants exhibit reduced arylsulfatase activity compared to snrk2.2 or psr1snrk2.2, respectively, but the sac1 mutation has little effect on the abundance of S deficiency-responsive transcripts in these strains, suggesting a post-transcriptional role for SAC1 in elicitation of S-starvation responses. Interestingly, P-starved psr1snrk2.2 cells bleach and die more rapidly than wild-type or psr1 strains, suggesting that activation of S-starvation responses during P deprivation is deleterious to the cell. From these results we infer that (i) P-deficient growth causes some internal S limitation, but the S-deficiency responses are normally inhibited during acclimation to P deprivation; (ii) the S-deficiency responses are not completely suppressed in P-deficient psr1 cells and consequently these cells synthesize some arylsulfatase and exhibit elevated levels of transcripts for S-deprivation genes; and (iii) this increased expression is controlled by regulators that modulate transcription of S-responsive genes during S-deprivation conditions. Overall, the work strongly suggests integration of the different circuits that control nutrient-deprivation responses in Chlamydomonas.
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Affiliation(s)
- Jeffrey L Moseley
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
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25
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Moellering ER, Miller R, Benning C. Molecular Genetics of Lipid Metabolism in the Model Green Alga Chlamydomonas reinhardtii. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/978-90-481-2863-1_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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26
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Effects of nitrogen sources on cell growth and lipid accumulation of green alga Neochloris oleoabundans. Appl Microbiol Biotechnol 2008; 81:629-36. [DOI: 10.1007/s00253-008-1681-1] [Citation(s) in RCA: 677] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/18/2008] [Accepted: 08/21/2008] [Indexed: 10/21/2022]
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