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Oh JJ, Ammu S, Vriend VD, Kieffer R, Kleiner FH, Balasubramanian S, Karana E, Masania K, Aubin-Tam ME. Growth, Distribution, and Photosynthesis of Chlamydomonas Reinhardtii in 3D Hydrogels. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2305505. [PMID: 37851509 DOI: 10.1002/adma.202305505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/16/2023] [Indexed: 10/20/2023]
Abstract
Engineered living materials (ELMs) are a novel class of functional materials that typically feature spatial confinement of living components within an inert polymer matrix to recreate biological functions. Understanding the growth and spatial configuration of cellular populations within a matrix is crucial to predicting and improving their responsive potential and functionality. Here, this work investigates the growth, spatial distribution, and photosynthetic productivity of eukaryotic microalga Chlamydomonas reinhardtii (C. reinhardtii) in three-dimensionally shaped hydrogels in dependence of geometry and size. The embedded C. reinhardtii cells photosynthesize and form confined cell clusters, which grow faster when located close to the ELM periphery due to favorable gas exchange and light conditions. Taking advantage of location-specific growth patterns, this work successfully designs and prints photosynthetic ELMs with increased CO2 capturing rate, featuring high surface to volume ratio. This strategy to control cell growth for higher productivity of ELMs resembles the already established adaptations found in multicellular plant leaves.
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Affiliation(s)
- Jeong-Joo Oh
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
| | - Satya Ammu
- Shaping Matter Lab, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, Delft, 2629 HS, The Netherlands
| | - Vivian Dorine Vriend
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
- Department of Sustainable Design Engineering, Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, Delft, 2628 CE, The Netherlands
| | - Roland Kieffer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
| | - Friedrich Hans Kleiner
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
| | - Srikkanth Balasubramanian
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
- Department of Sustainable Design Engineering, Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, Delft, 2628 CE, The Netherlands
| | - Elvin Karana
- Department of Sustainable Design Engineering, Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, Delft, 2628 CE, The Netherlands
| | - Kunal Masania
- Shaping Matter Lab, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, Delft, 2629 HS, The Netherlands
| | - Marie-Eve Aubin-Tam
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
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Liu D, Vargas-García CA, Singh A, Umen J. A cell-based model for size control in the multiple fission alga Chlamydomonas reinhardtii. Curr Biol 2023; 33:5215-5224.e5. [PMID: 37949064 PMCID: PMC10750806 DOI: 10.1016/j.cub.2023.10.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/03/2023] [Accepted: 10/16/2023] [Indexed: 11/12/2023]
Abstract
Understanding how population-size homeostasis emerges from stochastic individual cell behaviors remains a challenge in biology.1,2,3,4,5,6,7 The unicellular green alga Chlamydomonas reinhardtii (Chlamydomonas) proliferates using a multiple fission cell cycle, where a prolonged G1 phase is followed by n rounds of alternating division cycles (S/M) to produce 2n daughters. A "Commitment" sizer in mid-G1 phase ensures sufficient cell growth before completing the cell cycle. A mitotic sizer couples mother-cell size to division number (n) such that daughter size distributions are uniform regardless of mother size distributions. Although daughter size distributions were highly robust to altered growth conditions, ∼40% of daughter cells fell outside of the 2-fold range expected from a "perfect" multiple fission sizer.7,8 A simple intuitive power law model with stochastic noise failed to reproduce individual division behaviors of tracked single cells. Through additional iterative modeling, we identified an alternative modified threshold (MT) model, where cells need to cross a threshold greater than 2-fold their median starting size to become division-competent (i.e., Committed), after which their behaviors followed a power law model. The Commitment versus mitotic size threshold uncoupling in the MT model was likely a key pre-adaptation in the evolution of volvocine algal multicellularity. A similar experimental approach was used in size mutants mat3/rbr and dp1 that are, respectively, missing repressor or activator subunits of the retinoblastoma tumor suppressor complex (RBC). Both mutants showed altered relationships between Commitment and mitotic sizer, suggesting that RBC functions to decouple the two sizers.
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Affiliation(s)
- Dianyi Liu
- Donald Danforth Plant Science Center, 975 N Warson Rd, St. Louis, MO 63132, USA; Department of Biology, University of Missouri - St. Louis, 1 University Blvd, St. Louis, MO 63121, USA
| | | | - Abhyudai Singh
- Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE 19716, USA.
| | - James Umen
- Donald Danforth Plant Science Center, 975 N Warson Rd, St. Louis, MO 63132, USA.
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Chowdhary AK, Kishi M, Toda T. A novel process for the production of Chromochloris zofingiensis through dark-induced multi-nuclei formation. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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Kim JH, Dubey SK, Hwangbo K, Chung BY, Lee SS, Lee S. Application of ionizing radiation as an elicitor to enhance the growth and metabolic activities in Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2023; 14:1087070. [PMID: 36890890 PMCID: PMC9986495 DOI: 10.3389/fpls.2023.1087070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Chlamydomonas reinhardtii is a eukaryotic, unicellular photosynthetic organism and a potential algal platform for producing biomass and recombinant proteins for industrial use. Ionizing radiation is a potent genotoxic and mutagenic agent used for algal mutation breeding that induces various DNA damage and repair responses. In this study, however, we explored the counterintuitive bioeffects of ionizing radiation, such as X- and γ-rays, and its potential as an elicitor to facilitate batch or fed-batch cultivation of Chlamydomonas cells. A certain dose range of X- and γ-rays was shown to stimulate the growth and metabolite production of Chlamydomonas cells. X- or γ-irradiation with relatively low doses below 10 Gy substantially increased chlorophyll, protein, starch, and lipid content as well as growth and photosynthetic activity in Chlamydomonas cells without inducing apoptotic cell death. Transcriptome analysis demonstrated the radiation-induced changes in DNA damage response (DDR) and various metabolic pathways with the dose-dependent expression of some DDR genes, such as CrRPA30, CrFEN1, CrKU, CrRAD51, CrOASTL2, CrGST2, and CrRPA70A. However, the overall transcriptomic changes were not causally associated with growth stimulation and/or enhanced metabolic activities. Nevertheless, the radiation-induced growth stimulation was strongly enhanced by repetitive X-irradiation and/or subsequent cultivation with an inorganic carbon source, i.e., NaHCO3, but was significantly inhibited by treatment of ascorbic acid, a scavenger of reactive oxygen species (ROS). The optimal dose range of X-irradiation for growth stimulation differed by genotype and radiation sensitivity. Here, we suggest that ionizing radiation within a certain dose range determined by genotype-dependent radiation sensitivity could induce growth stimulation and enhance metabolic activities, including photosynthesis, chlorophyll, protein, starch, and lipid synthesis in Chlamydomonas cells via ROS signaling. The counterintuitive benefits of a genotoxic and abiotic stress factor, i.e., ionizing radiation, in a unicellular algal organism, i.e., Chlamydomonas, may be explained by epigenetic stress memory or priming effects associated with ROS-mediated metabolic remodeling.
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Affiliation(s)
- Jin-Hong Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeollabuk-do, Republic of Korea
- Department of Radiation Science and Technology, University of Science and Technology, Daejeon, Republic of Korea
| | - Shubham Kumar Dubey
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeollabuk-do, Republic of Korea
- Department of Radiation Science and Technology, University of Science and Technology, Daejeon, Republic of Korea
| | - Kwon Hwangbo
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeollabuk-do, Republic of Korea
| | - Byung Yeoup Chung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeollabuk-do, Republic of Korea
| | - Seung Sik Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeollabuk-do, Republic of Korea
- Department of Radiation Science and Technology, University of Science and Technology, Daejeon, Republic of Korea
| | - Sungbeom Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeollabuk-do, Republic of Korea
- Department of Radiation Science and Technology, University of Science and Technology, Daejeon, Republic of Korea
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Transcriptomic analysis of OsRUS1 overexpression rice lines with rapid and dynamic leaf rolling morphology. Sci Rep 2022; 12:6736. [PMID: 35468979 PMCID: PMC9038715 DOI: 10.1038/s41598-022-10784-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 04/13/2022] [Indexed: 01/12/2023] Open
Abstract
Moderate leaf rolling helps to form the ideotype of rice. In this study, six independent OsRUS1-GFP overexpression (OsRUS1-OX) transgenic rice lines with rapid and dynamic leaf rolling phenotype in response to sunlight were constructed. However, the mechanism is unknown. Here, RNA-Seq approach was utilized to identify differentially expressed genes between flag leaves of OsRUS1-OX and wildtype under sunlight. 2920 genes were differentially expressed between OsRUS1-OX and WT, of which 1660 upregulated and 1260 downregulated. Six of the 16 genes in GO: 0009415 (response to water stimulus) were significantly upregulated in OsRUS1-OX. The differentially expressed genes between WT and OsRUS1-OX were assigned to 110 KEGG pathways. 42 of the 222 genes in KEGG pathway dosa04075 (Plant hormone signal transduction) were differentially expressed between WT and OsRUS1-OX. The identified genes in GO:0009415 and KEGG pathway dosa04075 were good candidates to explain the leaf rolling phenotype of OsRUS1-OX. The expression patterns of the 15 genes identified by RNA-Seq were verified by qRT-PCR. Based on transcriptomic and qRT-PCR analysis, a mechanism for the leaf rolling phenotype of OsRUS1-OX was proposed. The differential expression profiles between WT and OsRUS1-OX established by this study provide important insights into the molecular mechanism behind the leaf rolling phenotype of OsRUS1-OX.
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Jong LW, Fujiwara T, Hirooka S, Miyagishima SY. Cell size for commitment to cell division and number of successive cell divisions in cyanidialean red algae. PROTOPLASMA 2021; 258:1103-1118. [PMID: 33675395 DOI: 10.1007/s00709-021-01628-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Several eukaryotic cell lineages proliferate by multiple fission cell cycles, during which cells grow to manyfold of their original size, then undergo several rounds of cell division without intervening growth. A previous study on volvocine green algae, including both unicellular and multicellular (colonial) species, showed a correlation between the minimum number of successive cell divisions without intervening cellular growth, and the threshold cell size for commitment to the first round of successive cell divisions: two times the average newly born daughter cell volume for unicellular Chlamydomonas reinhardtii, four times for four-celled Tetrabaena socialis, in which each cell in the colony produces a daughter colony by two successive cell divisions, and eight times for the eight-celled Gonium pectorale, in which each cell produces a daughter colony by three successive cell divisions. To assess whether this phenomenon is also applicable to other lineages, we have characterized cyanidialean red algae, namely, Cyanidioschyzon merolae, which proliferates by binary fission, as well as Cyanidium caldarium and Galdieria sulphuraria, which form up to four and 32 daughter cells (autospores), respectively, in a mother cell before hatching out. The result shows that there is also a correlation between the number of successive cell divisions and the threshold cell size for cell division or the first round of the successive cell divisions. In both C. merolae and C. caldarium, the cell size checkpoint for cell division(s) exists in the G1-phase, as previously shown in volvocine green algae. When C. merolae cells were arrested in the G1-phase and abnormally enlarged by conditional depletion of CDKA, the cells underwent two or more successive cell divisions without intervening cellular growth after recovery of CDKA, similarly to C. caldarium and G. sulphuraria. These results suggest that the threshold size for cell division is a major factor in determining the number of successive cell divisions and that evolutionary changes in the mechanism of cell size monitoring resulted in a variation of multiple fission cell cycle in eukaryotic algae.
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Affiliation(s)
- Lin Wei Jong
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan.
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Bilcke G, Osuna-Cruz CM, Santana Silva M, Poulsen N, D'hondt S, Bulankova P, Vyverman W, De Veylder L, Vandepoele K. Diurnal transcript profiling of the diatom Seminavis robusta reveals adaptations to a benthic lifestyle. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:315-336. [PMID: 33901335 DOI: 10.1111/tpj.15291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Coastal regions contribute an estimated 20% of annual gross primary production in the oceans, despite occupying only 0.03% of their surface area. Diatoms frequently dominate coastal sediments, where they experience large variations in light regime resulting from the interplay of diurnal and tidal cycles. Here, we report on an extensive diurnal transcript profiling experiment of the motile benthic diatom Seminavis robusta. Nearly 90% (23 328) of expressed protein-coding genes and 66.9% (1124) of expressed long intergenic non-coding RNAs showed significant expression oscillations and are predominantly phasing at night with a periodicity of 24 h. Phylostratigraphic analysis found that rhythmic genes are enriched in highly conserved genes, while diatom-specific genes are predominantly associated with midnight expression. Integration of genetic and physiological cell cycle markers with silica depletion data revealed potential new silica cell wall-associated gene families specific to diatoms. Additionally, we observed 1752 genes with a remarkable semidiurnal (12-h) periodicity, while the expansion of putative circadian transcription factors may reflect adaptations to cope with highly unpredictable external conditions. Taken together, our results provide new insights into the adaptations of diatoms to the benthic environment and serve as a valuable resource for the study of diurnal regulation in photosynthetic eukaryotes.
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Affiliation(s)
- Gust Bilcke
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, 9000, Belgium
| | - Cristina Maria Osuna-Cruz
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
- Bioinformatics Institute Ghent, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
| | - Marta Santana Silva
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Nicole Poulsen
- B CUBE Center for Molecular Bioengineering, Technical University of Dresden, Tatzberg 41, Dresden, 01307, Germany
| | - Sofie D'hondt
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
| | - Petra Bulankova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Wim Vyverman
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
| | - Lieven De Veylder
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
- Bioinformatics Institute Ghent, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
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Growth under Different Trophic Regimes and Synchronization of the Red Microalga Galdieria sulphuraria. Biomolecules 2021; 11:biom11070939. [PMID: 34202768 PMCID: PMC8301940 DOI: 10.3390/biom11070939] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 11/16/2022] Open
Abstract
The extremophilic unicellular red microalga Galdieria sulphuraria (Cyanidiophyceae) is able to grow autotrophically, or mixo- and heterotrophically with 1% glycerol as a carbon source. The alga divides by multiple fission into more than two cells within one cell cycle. The optimal conditions of light, temperature and pH (500 µmol photons m-2 s-1, 40 °C, and pH 3; respectively) for the strain Galdieria sulphuraria (Galdieri) Merola 002 were determined as a basis for synchronization experiments. For synchronization, the specific light/dark cycle, 16/8 h was identified as the precondition for investigating the cell cycle. The alga was successfully synchronized and the cell cycle was evaluated. G. sulphuraria attained two commitment points with midpoints at 10 and 13 h of the cell cycle, leading to two nuclear divisions, followed subsequently by division into four daughter cells. The daughter cells stayed in the mother cell wall until the beginning of the next light phase, when they were released. Accumulation of glycogen throughout the cell cycle was also described. The findings presented here bring a new contribution to our general understanding of the cell cycle in cyanidialean red algae, and specifically of the biotechnologically important species G. sulphuraria.
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Zachleder V, Ivanov IN, Kselíková V, Bialevich V, Vítová M, Ota S, Takeshita T, Kawano S, Bišová K. Characterization of Growth and Cell Cycle Events Affected by Light Intensity in the Green Alga Parachlorella kessleri: A New Model for Cell Cycle Research. Biomolecules 2021; 11:biom11060891. [PMID: 34203860 PMCID: PMC8232753 DOI: 10.3390/biom11060891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 11/16/2022] Open
Abstract
Multiple fission is a cell cycle variation leading to the production of more than two daughter cells. Here, we used synchronized cultures of the chlorococcal green alga Parachlorella kessleri to study its growth and pattern of cell division under varying light intensities. The time courses of DNA replication, nuclear and cellular division, cell size, total RNA, protein content, dry matter and accumulation of starch were observed at incident light intensities of 110, 250 and 500 µmol photons m−2s−1. Furthermore, we studied the effect of deuterated water on Parachlorella kessleri growth and division, to mimic the effect of stress. We describe a novel multiple fission cell cycle pattern characterized by multiple rounds of DNA replication leading to cell polyploidization. Once completed, multiple nuclear divisions were performed with each of them, immediately followed by protoplast fission, terminated by the formation of daughter cells. The multiple fission cell cycle was represented by several consecutive doublings of growth parameters, each leading to the start of a reproductive sequence. The number of growth doublings increased with increasing light intensity and led to division into more daughter cells. This study establishes the baseline for cell cycle research at the molecular level as well as for potential biotechnological applications, particularly directed synthesis of (deuterated) starch and/or neutral lipids as carbon and energy reserves.
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Affiliation(s)
- Vilém Zachleder
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.Z.); (I.N.I.); (V.K.); (V.B.); (M.V.)
| | - Ivan N. Ivanov
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.Z.); (I.N.I.); (V.K.); (V.B.); (M.V.)
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
| | - Veronika Kselíková
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.Z.); (I.N.I.); (V.K.); (V.B.); (M.V.)
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
| | - Vitali Bialevich
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.Z.); (I.N.I.); (V.K.); (V.B.); (M.V.)
| | - Milada Vítová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.Z.); (I.N.I.); (V.K.); (V.B.); (M.V.)
| | - Shuhei Ota
- Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan;
| | - Tsuyoshi Takeshita
- The University of Tokyo Future Center Initiative, Wakashiba 178 4 4, Kashiwa, Chiba 277-0871, Japan; (T.T.); (S.K.)
| | - Shigeyuki Kawano
- The University of Tokyo Future Center Initiative, Wakashiba 178 4 4, Kashiwa, Chiba 277-0871, Japan; (T.T.); (S.K.)
| | - Kateřina Bišová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.Z.); (I.N.I.); (V.K.); (V.B.); (M.V.)
- Correspondence: ; Tel.: +420-384-340-480
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Kselíková V, Zachleder V, Bišová K. To Divide or Not to Divide? How Deuterium Affects Growth and Division of Chlamydomonas reinhardtii. Biomolecules 2021; 11:861. [PMID: 34207920 PMCID: PMC8226696 DOI: 10.3390/biom11060861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/31/2021] [Accepted: 06/07/2021] [Indexed: 11/16/2022] Open
Abstract
Extensive in vivo replacement of hydrogen by deuterium, a stable isotope of hydrogen, induces a distinct stress response, reduces cell growth and impairs cell division in various organisms. Microalgae, including Chlamydomonas reinhardtii, a well-established model organism in cell cycle studies, are no exception. Chlamydomonas reinhardtii, a green unicellular alga of the Chlorophyceae class, divides by multiple fission, grows autotrophically and can be synchronized by alternating light/dark regimes; this makes it a model of first choice to discriminate the effect of deuterium on growth and/or division. Here, we investigate the effects of high doses of deuterium on cell cycle progression in C. reinhardtii. Synchronous cultures of C. reinhardtii were cultivated in growth medium containing 70 or 90% D2O. We characterize specific deuterium-induced shifts in attainment of commitment points during growth and/or division of C. reinhardtii, contradicting the role of the "sizer" in regulating the cell cycle. Consequently, impaired cell cycle progression in deuterated cultures causes (over)accumulation of starch and lipids, suggesting a promising potential for microalgae to produce deuterated organic compounds.
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Affiliation(s)
- Veronika Kselíková
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.K.); (V.Z.)
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
| | - Vilém Zachleder
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.K.); (V.Z.)
| | - Kateřina Bišová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37981 Třeboň, Czech Republic; (V.K.); (V.Z.)
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Starch Production in Chlamydomonas reinhardtii through Supraoptimal Temperature in a Pilot-Scale Photobioreactor. Cells 2021; 10:cells10051084. [PMID: 34062892 PMCID: PMC8147326 DOI: 10.3390/cells10051084] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 01/29/2023] Open
Abstract
An increase in temperature can have a profound effect on the cell cycle and cell division in green algae, whereas growth and the synthesis of energy storage compounds are less influenced. In Chlamydomonas reinhardtii, laboratory experiments have shown that exposure to a supraoptimal temperature (39 °C) causes a complete block of nuclear and cellular division accompanied by an increased accumulation of starch. In this work we explore the potential of supraoptimal temperature as a method to promote starch production in C. reinhardtii in a pilot-scale photobioreactor. The method was successfully applied and resulted in an almost 3-fold increase in the starch content of C. reinhardtii dry matter. Moreover, a maximum starch content at the supraoptimal temperature was reached within 1-2 days, compared with 5 days for the control culture at the optimal temperature (30 °C). Therefore, supraoptimal temperature treatment promotes rapid starch accumulation and suggests a viable alternative to other starch-inducing methods, such as nutrient depletion. Nevertheless, technical challenges, such as bioreactor design and light availability within the culture, still need to be dealt with.
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Li X, Slavens S, Crunkleton DW, Johannes TW. Interactive effect of light quality and temperature on Chlamydomonas reinhardtii growth kinetics and lipid synthesis. ALGAL RES 2021. [DOI: 10.1016/j.algal.2020.102127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Moudříková Š, Ivanov IN, Vítová M, Nedbal L, Zachleder V, Mojzeš P, Bišová K. Comparing Biochemical and Raman Microscopy Analyses of Starch, Lipids, Polyphosphate, and Guanine Pools during the Cell Cycle of Desmodesmus quadricauda. Cells 2021; 10:cells10010062. [PMID: 33401566 PMCID: PMC7824393 DOI: 10.3390/cells10010062] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/24/2020] [Accepted: 12/29/2020] [Indexed: 11/30/2022] Open
Abstract
Photosynthetic energy conversion and the resulting photoautotrophic growth of green algae can only occur in daylight, but DNA replication, nuclear and cellular divisions occur often during the night. With such a light/dark regime, an algal culture becomes synchronized. In this study, using synchronized cultures of the green alga Desmodesmus quadricauda, the dynamics of starch, lipid, polyphosphate, and guanine pools were investigated during the cell cycle by two independent methodologies; conventional biochemical analyzes of cell suspensions and confocal Raman microscopy of single algal cells. Raman microscopy reports not only on mean concentrations, but also on the distribution of pools within cells. This is more sensitive in detecting lipids than biochemical analysis, but both methods—as well as conventional fluorescence microscopy—were comparable in detecting polyphosphates. Discrepancies in the detection of starch by Raman microscopy are discussed. The power of Raman microscopy was proven to be particularly valuable in the detection of guanine, which was traceable by its unique vibrational signature. Guanine microcrystals occurred specifically at around the time of DNA replication and prior to nuclear division. Interestingly, guanine crystals co-localized with polyphosphates in the vicinity of nuclei around the time of nuclear division.
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Affiliation(s)
- Šárka Moudříková
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic; (Š.M.); (P.M.)
- Institute of Bio- and Geosciences/Plant Sciences (IBG-2), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, D-52428 Jülich, Germany;
| | - Ivan Nedyalkov Ivanov
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, CZ-37981 Třeboň, Czech Republic; (I.N.I.); (M.V.); (V.Z.)
- Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005 České Budějovice, Czech Republic
| | - Milada Vítová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, CZ-37981 Třeboň, Czech Republic; (I.N.I.); (M.V.); (V.Z.)
| | - Ladislav Nedbal
- Institute of Bio- and Geosciences/Plant Sciences (IBG-2), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, D-52428 Jülich, Germany;
| | - Vilém Zachleder
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, CZ-37981 Třeboň, Czech Republic; (I.N.I.); (M.V.); (V.Z.)
| | - Peter Mojzeš
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic; (Š.M.); (P.M.)
- Institute of Bio- and Geosciences/Plant Sciences (IBG-2), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, D-52428 Jülich, Germany;
| | - Kateřina Bišová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, CZ-37981 Třeboň, Czech Republic; (I.N.I.); (M.V.); (V.Z.)
- Correspondence: ; Tel.: +420-384-340-485
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Regulation of Multiple Fission and Cell-Cycle-Dependent Gene Expression by CDKA1 and the Rb-E2F Pathway in Chlamydomonas. Curr Biol 2020; 30:1855-1865.e4. [PMID: 32243861 DOI: 10.1016/j.cub.2020.03.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/06/2020] [Accepted: 03/09/2020] [Indexed: 01/07/2023]
Abstract
The green alga Chlamydomonas proliferates by "multiple fission": a long G1 with >10-fold cell growth followed by multiple rapid divisions. Cells above a critical size threshold are "committed" and will divide independent of light and further cell growth. The number of divisions carried out depends on the initial size of the committed mother cell. Here, I show that CDKA1, the ortholog of the yeast and animal mitotic inducer CDK1, regulates the critical size for commitment. The Rb/E2F/Dp1 pathway regulates division number as well as commitment size. Epistasis analysis indicated that CDKA1 and Rb/E2F/Dp1 regulate multiple fission by distinct mechanisms. Rb-E2F/Dp1 regulates G1/S gene expression in animals and land plants. Transcriptome analysis showed that mat3 or dp1 disruption altered regulation of a large group of cell-division-associated genes with respect to cell size, but not with respect to synchronization timing. In contrast, cdka1 inactivation disturbed both temporal and cell-size regulation of expression. These defects were enhanced by double inactivation of cdka1 and dp1, suggesting interaction between CDKA1 and the Rb-E2F/Dp1 pathways in regulating cell-cycle-specific gene expression and cell-cycle initiation. In the context of a theoretical model for regulation of Chlamydomonas multiple fission, these results suggest that CDKA1 may promote a switch into a division-competent state, and E2F/Dp1 may promote maintenance of this state.
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Heldt FS, Tyson JJ, Cross FR, Novák B. A Single Light-Responsive Sizer Can Control Multiple-Fission Cycles in Chlamydomonas. Curr Biol 2020; 30:634-644.e7. [DOI: 10.1016/j.cub.2019.12.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/25/2019] [Accepted: 12/09/2019] [Indexed: 12/18/2022]
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16
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Cell Cycle Arrest by Supraoptimal Temperature in the Alga Chlamydomonas reinhardtii. Cells 2019; 8:cells8101237. [PMID: 31614608 PMCID: PMC6829867 DOI: 10.3390/cells8101237] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 12/20/2022] Open
Abstract
Temperature is one of the key factors affecting growth and division of algal cells. High temperature inhibits the cell cycle in Chlamydomonas reinhardtii. At 39 °C, nuclear and cellular divisions in synchronized cultures were blocked completely, while DNA replication was partly affected. In contrast, growth (cell volume, dry matter, total protein, and RNA) remained unaffected, and starch accumulated at very high levels. The cell cycle arrest could be removed by transfer to 30 °C, but a full recovery occurred only in cultures cultivated up to 14 h at 39 °C. Thereafter, individual cell cycle processes began to be affected in sequence; daughter cell release, cell division, and DNA replication. Cell cycle arrest was accompanied by high mitotic cyclin-dependent kinase activity that decreased after completion of nuclear and cellular division following transfer to 30 °C. Cell cycle arrest was, therefore, not caused by a lack of cyclin-dependent kinase activity but rather a blockage in downstream processes.
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17
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Ivanov IN, Vítová M, Bišová K. Growth and the cell cycle in green algae dividing by multiple fission. Folia Microbiol (Praha) 2019; 64:663-672. [PMID: 31347103 DOI: 10.1007/s12223-019-00741-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/15/2019] [Indexed: 11/24/2022]
Abstract
Most cells divide into two daughter cells; however, some green algae can have different division patterns in which a single mother cell can sometimes give rise to up to thousands of daughter cells. Although such cell cycle patterns can be very complex, they are governed by the same general concepts as the most common binary fission. Moreover, cell cycle progression appears to be connected with size, since cells need to ensure that their size after division will not drop below the limit required for survival. Although the exact mechanism that lets cells measure cell size remains largely unknown, there have been several prominent hypotheses that try to explain it.
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Affiliation(s)
- Ivan Nedyalkov Ivanov
- Institute of Microbiology, Centre Algatech, Laboratory of Cell Cycles of Algae, Opatovický mlýn, Czech Academy of Sciences, 379 81, Třeboň, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
| | - Milada Vítová
- Institute of Microbiology, Centre Algatech, Laboratory of Cell Cycles of Algae, Opatovický mlýn, Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
| | - Kateřina Bišová
- Institute of Microbiology, Centre Algatech, Laboratory of Cell Cycles of Algae, Opatovický mlýn, Czech Academy of Sciences, 379 81, Třeboň, Czech Republic.
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18
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Improved Algal Toxicity Test System for Robust Omics-Driven Mode-of-Action Discovery in Chlamydomonas reinhardtii. Metabolites 2019; 9:metabo9050094. [PMID: 31083411 PMCID: PMC6572051 DOI: 10.3390/metabo9050094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 01/05/2023] Open
Abstract
Algae are key components of aquatic food chains. Consequently, they are internationally recognised test species for the environmental safety assessment of chemicals. However, existing algal toxicity test guidelines are not yet optimized to discover molecular modes of action, which require highly-replicated and carefully controlled experiments. Here, we set out to develop a robust, miniaturised and scalable Chlamydomonas reinhardtii toxicity testing approach tailored to meet these demands. We primarily investigated the benefits of synchronised cultures for molecular studies, and of exposure designs that restrict chemical volatilisation yet yield sufficient algal biomass for omics analyses. Flow cytometry and direct-infusion mass spectrometry metabolomics revealed significant and time-resolved changes in sample composition of synchronised cultures. Synchronised cultures in sealed glass vials achieved adequate growth rates at previously unachievably-high inoculation cell densities, with minimal pH drift and negligible chemical loss over 24-h exposures. Algal exposures to a volatile test compound (chlorobenzene) yielded relatively high reproducibility of metabolic phenotypes over experimental repeats. This experimental test system extends existing toxicity testing formats to allow highly-replicated, omics-driven, mode-of-action discovery.
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19
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Ramírez-Rodríguez AE, Bañuelos-Hernández B, García-Soto MJ, Govea-Alonso DG, Rosales-Mendoza S, Alfaro de la Torre MC, Monreal-Escalante E, Paz-Maldonado LMT. Arsenic removal using Chlamydomonas reinhardtii modified with the gene acr3 and enhancement of its performance by decreasing phosphate in the growing media. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2019; 21:617-623. [PMID: 30873857 DOI: 10.1080/15226514.2018.1546274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Arsenic contamination of groundwater is a significant problem in countries like Mexico, where San Luis Potosi is among the regions registering severe levels of it. Bioremediation with microalgae capable to absorb and metabolize metals or metalloids like arsenic reduces their toxicity and is a cost-effective approach compared to physical-chemical processes. We evaluated the capability of Chlamydomonas reinhardtii to remove arsenate and compared it with an acr3-modified recombinant strain, which we produced by transforming the wild-type strain with Agrobacterium tumefaciens using the construct pARR1 including a synthetic, optimized acr3 gene from Pteris vittata, a hyper-accumulator of arsenic. We monitored the growth of both strains in media with arsenate, containing a standard or a 10-fold decreased amount of phosphate. Comparing both strains in media initially with 0.5, 1, and 1.5 mg/L of arsenate, the acr3-modified strain removed 1.5 to 3 times more arsenic than the wild-type strain. Moreover, the arsenic uptake rate increased 1.2 to 2.3 times when growing the acr3-modified strain in media with decreased phosphate, while the uptake rate for the wild-type strain scarcely changed under the same conditions. These results confirm the expression of the acr3 gene in C. reinhardtii and its potential application to remove arsenic.
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Affiliation(s)
- Angélica E Ramírez-Rodríguez
- a Laboratorio de Biorreactores, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - Bernardo Bañuelos-Hernández
- b Laboratorio de Biofarmacéuticos Recombinantes, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - Mariano J García-Soto
- a Laboratorio de Biorreactores, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - Dania G Govea-Alonso
- b Laboratorio de Biofarmacéuticos Recombinantes, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - Sergio Rosales-Mendoza
- b Laboratorio de Biofarmacéuticos Recombinantes, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - M Catalina Alfaro de la Torre
- c Laboratorio de Elementos Traza, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - Elizabeth Monreal-Escalante
- b Laboratorio de Biofarmacéuticos Recombinantes, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
| | - Luz M T Paz-Maldonado
- a Laboratorio de Biorreactores, Facultad de Ciencias Químicas Universidad Autónoma de San Luis Potosí , San Luis Potosí , México
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20
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Kato Y, Fujihara Y, Vavricka CJ, Chang JS, Hasunuma T, Kondo A. Light/dark cycling causes delayed lipid accumulation and increased photoperiod-based biomass yield by altering metabolic flux in oleaginous Chlamydomonas sp. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:39. [PMID: 30828384 PMCID: PMC6383270 DOI: 10.1186/s13068-019-1380-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Light/dark cycling is an inevitable outdoor culture condition for microalgal biofuel production; however, the influence of this cycling on cellular lipid production has not been clearly established. The general aim of this study was to determine the influence of light/dark cycling on microalgal biomass production and lipid accumulation. To achieve this goal, specific causative mechanisms were investigated using a metabolomics approach. Laboratory scale photoautotrophic cultivations of the oleaginous green microalga Chlamydomonas sp. JSC4 were performed under continuous light (LL) and light/dark (LD) conditions. RESULTS Lipid accumulation and carbohydrate degradation were delayed under the LD condition compared with that under the LL condition. Metabolomic analysis revealed accumulation of phosphoenolpyruvate and decrease of glycerol 3-phosphate under the LD condition, suggesting that the imbalance of these metabolites is a source of delayed lipid accumulation. When accounting for light dosage, biomass yield under the LD condition was significantly higher than that under the LL condition. Dynamic metabolic profiling showed higher levels of lipid/carbohydrate anabolism (including production of 3-phosphoglycerate, fructose 6-phosphate, glucose 6-phosphate, phosphoenolpyruvate and acetyl-CoA) from CO2 under the LD condition, indicating higher CO2 fixation than that of the LL condition. CONCLUSIONS Photoperiods define lipid accumulation and biomass production, and light/dark cycling was determined as a critical obstacle for lipid production in JSC4. Conversions of phosphoenolpyruvate to pyruvate and 3-phosphoglycerate to glycerol 3-phosphate are the candidate rate-limiting steps responsible for delayed lipid accumulation. The accumulation of substrates including ribulose 5-phosphate could be explained by the close relationship of increased biomass yield with enhanced CO2 fixation. The present study investigated the influence of light/dark cycling on lipid production by direct comparison with continuous illumination for the first time, and revealed underlying metabolic mechanisms and candidate metabolic rate-limiting steps during light/dark cycling. These findings suggest promising targets to metabolically engineer improved lipid production.
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Affiliation(s)
- Yuichi Kato
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Yusuke Fujihara
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Christopher J. Vavricka
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 701 Taiwan
- Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, 701 Taiwan
| | - Tomohisa Hasunuma
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Akihiko Kondo
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
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Zachleder V, Ivanov I, Vítová M, Bišová K. Effects of cyclin-dependent kinase activity on the coordination of growth and the cell cycle in green algae at different temperatures. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:845-858. [PMID: 30395238 DOI: 10.1093/jxb/ery391] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/22/2018] [Indexed: 06/08/2023]
Abstract
The progression of the cell cycle in green algae dividing by multiple fission is, under otherwise unlimited conditions, affected by the growth rate, set by a combination of light intensity and temperature. In this study, we compared the cell cycle characteristics of Desmodesmus quadricauda at 20 °C or 30 °C and upon shifts between these two temperatures. The duration of the cell cycle in cells grown under continuous illumination at 20 °C was more than double that at 30 °C, suggesting that it was set directly by the growth rate. Similarly, the amounts of DNA, RNA, and bulk protein content per cell at 20 °C were approximately double those of cells grown at the higher temperature. For the shift experiments, cells grown at either 20 °C or 30 °C were transferred to darkness to prevent further growth, and then cultivated at the same or the other temperature. Upon transfer to the lower temperature, fewer nuclei and daughter cells were produced, and not all cells were able to finish the cell cycle by division, remaining multinuclear. Correspondingly, cells placed in the dark at the higher temperature divided faster into more daughter cells than the control cells. These differences correlated with shifts in the preceding cyclin-dependent kinase activity, suggesting that cell cycle progression was not related to growth rate or cell biomass but correlated with cyclin-dependent kinase activity.
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Affiliation(s)
- Vilém Zachleder
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology, Czech Academy of Sciences, Opatovický mlýn, Trebon, Czech Republic
| | - Ivan Ivanov
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology, Czech Academy of Sciences, Opatovický mlýn, Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Milada Vítová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology, Czech Academy of Sciences, Opatovický mlýn, Trebon, Czech Republic
| | - Katerina Bišová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology, Czech Academy of Sciences, Opatovický mlýn, Trebon, Czech Republic
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22
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Shene C, Asenjo JA, Chisti Y. Metabolic modelling and simulation of the light and dark metabolism of Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:1076-1088. [PMID: 30168220 DOI: 10.1111/tpj.14078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 08/15/2018] [Accepted: 08/20/2018] [Indexed: 05/10/2023]
Abstract
A metabolic network model of the green microalga Chlamydomonas reinhardtii was used to characterize photoautotrophic and heterotrophic (i.e. growth on stored compounds) growth under light and dark, respectively. The metabolic network comprised 2514 reactions distributed among nine intracellular compartments and the extracellular space. The metabolic network included all the key biochemical pathways for synthesis and metabolism of starch and triacylglycerols (TAGs). Under light and nitrogen limitation, the model simulated the accumulation of the energy-rich compounds (TAGs and starch) in the cell. In the dark, the model could simulate cell growth and maintenance on stored compounds. The model-predicted consumption rates of storage compounds (starch or TAGs) to enable growth in the dark, were found to be greater than the rates of synthesis under light. This implied utilization of the storage compounds for cell maintenance in the dark. Under constant illumination, the simulations of cell growth and intracellular starch content agreed closely with independent experimental data. In other simulations, compared with the case without photorespiration, light uptake rate increased 1.04-fold when the ratio of the rates of oxygenation and carboxylation (Rubisco) was 0.1. Although extensive experimental work exists on culture and physiology of microalgae, it does not allow quantitative predictions of the influence of dark metabolism on the productivity of metabolites to be made. This limitation is overcome using the present model. A metabolic network model of Chlamydomonas reinhardtii is shown to simulate growth and synthesis of energy-rich compounds (triacylglycerols and starch) under light. The same model also simulates dark growth and maintenance through consumption of the stored energy-rich compounds.
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Affiliation(s)
- Carolina Shene
- Department of Chemical Engineering and Center of Food Biotechnology and Bioseparations, BIOREN, Universidad de La Frontera, Casilla 54-D, Temuco, Chile
- Centre for Biotechnology and Bioengineering (CeBiB), Universidad de La Frontera, Temuco, Chile
| | - Juan A Asenjo
- Centre for Biotechnology and Bioengineering (CeBiB), Department of Chemical Engineering and Biotechnology, Universidad de Chile, Beauchef 851, Santiago, Chile
| | - Yusuf Chisti
- School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand
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23
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Metabolomic profiles of tropical Chlorella and Parachlorella species in response to physiological changes during exponential and stationary growth phase. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.08.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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24
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Tassoni A, Awad N, Griffiths G. Effect of ornithine decarboxylase and norspermidine in modulating cell division in the green alga Chlamydomonas reinhardtii. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 123:125-131. [PMID: 29232652 DOI: 10.1016/j.plaphy.2017.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 06/07/2023]
Abstract
The extensive genetic resources of Chlamydomonas has led to its widespread use as a model system for understanding fundamental processes in plant cells, including rates of cell division potentially modulated through polyamines. Putrescine was the major polyamine in both free (88%) and membrane-bound fractions (93%) while norspermidine was the next most abundant in these fractions accounting for 11% and 6%, respectively. Low levels of diaminopropane, spermidine and spermine were also observed although no cadaverine or norspermine were detected. Ornithine decarboxylase (ODC, EC 4.1.1.17) activity was almost five times higher than arginine decarboxylase (ADC, EC 4.1.1.19) and is the major route of putrescine synthesis. The fluoride analogue of ornithine (α-DFMO) inhibited membrane associated ODC activity whilst simultaneously stimulating cell division in a dose dependent manner. Following exposure to α-DFMO the putrescine content in the cells declined while the norspermidine content increased over two fold. Addition of norspermidine to cultures stimulated cell division mimicking the effects observed using DFMO and also reversed the inhibitory effects of cyclohexylamine on growth. The results reveal that ODC is the major route to polyamine formation in the Chlamydomonas CC-406 cell-wall mutant, in contrast to the preferential ADC route reported for Chlorella vulgaris, suggesting that significant species differences exist in biosynthetic pathways which modulate endogenous polyamine levels in green algae.
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Affiliation(s)
- Annalisa Tassoni
- Department of Biological, Geological and Environmental Sciences, Via Irnerio 42, University of Bologna, 40126, Bologna, Italy.
| | - Nahid Awad
- European Bioenergy Research Institute, Aston University, Birmingham, B4 7ET, UK
| | - Gareth Griffiths
- European Bioenergy Research Institute, Aston University, Birmingham, B4 7ET, UK.
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Düner M, Lambertz J, Mügge C, Hemschemeier A. The soluble guanylate cyclase CYG12 is required for the acclimation to hypoxia and trophic regimes in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:311-337. [PMID: 29161457 DOI: 10.1111/tpj.13779] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/03/2017] [Accepted: 11/09/2017] [Indexed: 05/27/2023]
Abstract
Oxygenic phototrophs frequently encounter environmental conditions that result in intracellular energy crises. Growth of the unicellular green alga Chlamydomonas reinhardtii in hypoxia in the light depends on acclimatory responses of which the induction of photosynthetic cyclic electron flow is essential. The microalga cannot grow in the absence of molecular oxygen (O2 ) in the dark, although it possesses an elaborate fermentation metabolism. Not much is known about how the microalga senses and signals the lack of O2 or about its survival strategies during energy crises. Recently, nitric oxide (NO) has emerged to be required for the acclimation of C. reinhardtii to hypoxia. In this study, we show that the soluble guanylate cyclase (sGC) CYG12, a homologue of animal NO sensors, is also involved in this response. CYG12 is an active sGC, and post-transcriptional down-regulation of the CYG12 gene impairs hypoxic growth and gene expression in C. reinhardtii. However, it also results in a disturbed photosynthetic apparatus under standard growth conditions and the inability to grow heterotrophically. Transcriptome profiles indicate that the mis-expression of CYG12 results in a perturbation of responses that, in the wild-type, maintain the cellular energy budget. We suggest that CYG12 is required for the proper operation of the photosynthetic apparatus which, in turn, is essential for survival in hypoxia and darkness.
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Affiliation(s)
- Melis Düner
- Department of Plant Biochemistry, Workgroup Photobiotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Jan Lambertz
- Department of Plant Biochemistry, Workgroup Photobiotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Carolin Mügge
- Junior Research Group for Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Anja Hemschemeier
- Department of Plant Biochemistry, Workgroup Photobiotechnology, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, 44801, Bochum, Germany
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Jüppner J, Mubeen U, Leisse A, Caldana C, Brust H, Steup M, Herrmann M, Steinhauser D, Giavalisco P. Dynamics of lipids and metabolites during the cell cycle of Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:331-343. [PMID: 28742931 DOI: 10.1111/tpj.13642] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/17/2017] [Accepted: 07/19/2017] [Indexed: 05/12/2023]
Abstract
Metabolites and lipids are the final products of enzymatic processes, distinguishing the different cellular functions and activities of single cells or whole tissues. Understanding these cellular functions within a well-established model system requires a systemic collection of molecular and physiological information. In the current report, the green alga Chlamydomonas reinhardtii was selected to establish a comprehensive workflow for the detailed multi-omics analysis of a synchronously growing cell culture system. After implementation and benchmarking of the synchronous cell culture, a two-phase extraction method was adopted for the analysis of proteins, lipids, metabolites and starch from a single sample aliquot of as little as 10-15 million Chlamydomonas cells. In a proof of concept study, primary metabolites and lipids were sampled throughout the diurnal cell cycle. The results of these time-resolved measurements showed that single compounds were not only coordinated with each other in different pathways, but that these complex metabolic signatures have the potential to be used as biomarkers of various cellular processes. Taken together, the developed workflow, including the synchronized growth of the photoautotrophic cell culture, in combination with comprehensive extraction methods and detailed metabolic phenotyping has the potential for use in in-depth analysis of complex cellular processes, providing essential information for the understanding of complex biological systems.
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Affiliation(s)
- Jessica Jüppner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Umarah Mubeen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrea Leisse
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
- Brazilian Bioethanol Science and Technology Laboratory/CNPEM, Rua Giuseppe Máximo Scolfano 10000, 13083-970, Campinas, Brazil
| | - Henrike Brust
- Institute for Biochemistry and Biology, University of Potsdam, 14476, Potsdam-Golm, Germany
| | - Martin Steup
- Institute for Biochemistry and Biology, University of Potsdam, 14476, Potsdam-Golm, Germany
- University of Toronto c/o Hospital for Sick Children, PGCRL 14.9420, 72 Elm St, Toronto, ON M561H3, Canada
| | - Marion Herrmann
- Institute for Human Genetics, Humboldt University Berlin, Charité, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Dirk Steinhauser
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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Furse S, Shearman GC. Do lipids shape the eukaryotic cell cycle? Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:9-19. [PMID: 28964796 DOI: 10.1016/j.bbalip.2017.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/07/2017] [Accepted: 09/24/2017] [Indexed: 10/18/2022]
Abstract
Successful passage through the cell cycle presents a number of structural challenges to the cell. Inceptive studies carried out in the last five years have produced clear evidence of modulations in the lipid profile (sometimes referred to as the lipidome) of eukaryotes as a function of the cell cycle. This mounting body of evidence indicates that lipids play key roles in the structural transformations seen across the cycle. The accumulation of this evidence coincides with a revolution in our understanding of how lipid composition regulates a plethora of biological processes ranging from protein activity through to cellular signalling and membrane compartmentalisation. In this review, we discuss evidence from biological, chemical and physical studies of the lipid fraction across the cell cycle that demonstrate that lipids are well-developed cellular components at the heart of the biological machinery responsible for managing progress through the cell cycle. Furthermore, we discuss the mechanisms by which this careful control is exercised.
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Affiliation(s)
- Samuel Furse
- NucReg Research Programme, Molekylærbiologisk institutt, Unversitetet i Bergen, Thormøhlens gate 55, 5008, Bergen, Norway; Core Metabolomics and Lipidomics Laboratory, Department of Biochemistry, University of Cambridge, c/o Level 4, Pathology Building, Addenbrookes Hospital, Cambridge, CB2 0QQ, United Kingdom..
| | - Gemma C Shearman
- Faculty of Science, Engineering and Computing, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, United Kingdom
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Effects of chrysolaminarin synthase knockdown in the diatom Thalassiosira pseudonana: Implications of reduced carbohydrate storage relative to green algae. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.01.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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29
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de Winter L, Cabanelas I, Órfão A, Vaessen E, Martens D, Wijffels R, Barbosa M. The influence of day length on circadian rhythms of Neochloris oleoabundans. ALGAL RES 2017. [DOI: 10.1016/j.algal.2016.12.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Shelton DE, Leslie MP, Michod RE. Models of cell division initiation in Chlamydomonas: A challenge to the consensus view. J Theor Biol 2017; 412:186-197. [PMID: 27816674 DOI: 10.1016/j.jtbi.2016.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 09/19/2016] [Accepted: 10/25/2016] [Indexed: 11/28/2022]
Abstract
We develop and compare two models for division initiation in cells of the unicellular green alga Chlamydomonas reinhardtii, a topic that has remained controversial in spite of years of empirical work. Achieving a better understanding of C. reinhardtii cell cycle regulation is important because this species is used in studies of fundamental eukaryotic cell features and in studies of the evolution of multicellularity. C. reinhardtii proliferates asexually by multiple fission, interspersing rapid rounds of symmetric division with prolonged periods of growth. Our Model 1 reflects major elements of the current consensus view on C. reinhardtii division initiation, with cells first growing to a specific size, then waiting for a particular time prior to division initiation. In Model 2, our proposed alternative, growing cells divide when they have reached a growth-rate-dependent target size. The two models imply a number of different empirical patterns. We highlight these differences alongside published data, which currently fall short of unequivocally distinguishing these differences in predicted cell behavior. Nevertheless, several lines of evidence are suggestive of more Model 2-like behavior than Model 1-like behavior. Our specification of these models adds rigor to issues that have too often been worked out in relation to loose, verbal models and is directly relevant to future development of informative experiments.
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Affiliation(s)
- Deborah E Shelton
- Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E. Lowell St. Tucson, AZ 85721, United States.
| | - Martin P Leslie
- Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E. Lowell St. Tucson, AZ 85721, United States
| | - Richard E Michod
- Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E. Lowell St. Tucson, AZ 85721, United States; Kavli Institute for Theoretical Physics, University of California Santa Barbara, Santa Barbara, CA 93106, United States
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31
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de Winter L, Cabanelas ITD, Martens DE, Wijffels RH, Barbosa MJ. The influence of day/night cycles on biomass yield and composition of Neochloris oleoabundans. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:104. [PMID: 28439297 PMCID: PMC5401387 DOI: 10.1186/s13068-017-0762-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 03/18/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND Day/night cycles regulate the circadian clock of organisms to program daily activities. Many species of microalgae have a synchronized cell division when grown under a day/night cycle, and synchronization might influence biomass yield and composition. Therefore, the aim of this study was to study the influence of day/night cycle on biomass yield and composition of the green microalgae Neochloris oleoabundans. Hence, we compared continuous turbidostat cultures grown under continuous light with cultures grown under simulated day/night cycles. RESULTS Under day/night cycles, cultures were synchronized as cell division was scheduled in the night, whereas under continuous light cell division occurred randomly synchronized cultures were able to use the light 10-15% more efficiently than non-synchronized cultures. Our results indicate that the efficiency of light use varies over the cell cycle and that synchronized cell division provides a fitness benefit to microalgae. Biomass composition under day/night cycles was similar to continuous light, with the exception of starch content. The starch content was higher in cultures under continuous light, most likely because the cells never had to respire starch to cover for maintenance during dark periods. Day/night cycles were provided in a 'block' (continuous light intensity during the light period) and in a 'sine' (using a sine function to simulate light intensities from sunrise to sunset). There were no differences in biomass yield or composition between these two ways of providing light (in a 'block' or in a 'sine'). CONCLUSIONS The biomass yield and composition of N. oleoabundans were influenced by day/night cycles. These results are important to better understand the relations between research done under continuous light conditions and with day/night cycle conditions. Our findings also imply that more research should be done under day/night cycles.
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Affiliation(s)
- Lenneke de Winter
- Bioprocess Engineering, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
- Wetsus-Center of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
| | | | - Dirk E. Martens
- Bioprocess Engineering, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
| | - René H. Wijffels
- Bioprocess Engineering, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
| | - Maria J. Barbosa
- Bioprocess Engineering, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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Wagner I, Posten C. Pressure reduction affects growth and morphology of Chlamydomonas reinhardtii. Eng Life Sci 2016; 17:552-560. [PMID: 32624800 DOI: 10.1002/elsc.201600131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 11/04/2016] [Accepted: 11/08/2016] [Indexed: 11/10/2022] Open
Abstract
Cellular perception of pressure is a largely unknown field in microalgae research although it should be addressed for optimization of a photobioreactor design regarding typically occurring pressure cycles. Also for the purpose of using microalgae as basic modules for material cycles in controlled ecological life support systems, the absence of pressure in outer space or the low absolute pressures on other planets is an abiotic factor that needs to be considered for design of integrated microalgae-based modules. The aim of this work is to study the effects of lowered pressure and pressure changes on photosynthesis as well as morphology. Two Chlamydomonas reinhardtii wild-type strains were exposed to controlled pressure patterns during batch cultivations. Sudden pressure changes should test for existing threshold values for cell survival to mimic such events during space missions. Algae were grown inside a 2 L photobioreactor with an integrated vacuum pump ensuring constant pressures down to 700 mbar. Cultivation samples were analyzed for OD750, cell dry weight, and morphology via light microscope. Chlamydomonas reinhardtii CC-1690 cells showed decreased growth rates, higher carbon dioxide uptake rates, and unchanged oxygen production rates at lower pressures. For sudden pressures changes in the range of 300 mbar no fatal threshold was determined. This study shows that pressure reduction affects growth, gas exchange rates, and morphology. Within the tested pressure range no fatal threshold value was reached.
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Affiliation(s)
- Ines Wagner
- Department of Bioprocess Engineering KIT Karlsruhe Institute of Technology Karlsruhe Germany
| | - Clemens Posten
- Department of Bioprocess Engineering KIT Karlsruhe Institute of Technology Karlsruhe Germany
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Hlavová M, Vítová M, Bišová K. Synchronization of Green Algae by Light and Dark Regimes for Cell Cycle and Cell Division Studies. Methods Mol Biol 2016; 1370:3-16. [PMID: 26659950 DOI: 10.1007/978-1-4939-3142-2_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A synchronous population of cells is one of the prerequisites for studying cell cycle processes such as DNA replication, nuclear and cellular division. Green algae dividing by multiple fission represent a unique single cell system enabling the preparation of highly synchronous cultures by application of a light-dark regime similar to what they experience in nature. This chapter provides detailed protocols for synchronization of different algal species by alternating light-dark cycles; all critical points are discussed extensively. Moreover, detailed information on basic analysis of cell cycle progression in such cultures is presented, including analyses of nuclear, cellular, and chloroplast divisions. Modifications of basic protocols that enable changes in cell cycle progression are also suggested so that nuclear or chloroplast divisions can be followed separately.
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Affiliation(s)
- Monika Hlavová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology CAS, Opatovický mlýn, Třeboň, 379 81, Czech Republic
| | - Milada Vítová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology CAS, Opatovický mlýn, Třeboň, 379 81, Czech Republic
| | - Kateřina Bišová
- Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology CAS, Opatovický mlýn, Třeboň, 379 81, Czech Republic.
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34
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Vitova M, Bisova K, Kawano S, Zachleder V. Accumulation of energy reserves in algae: From cell cycles to biotechnological applications. Biotechnol Adv 2015; 33:1204-18. [DOI: 10.1016/j.biotechadv.2015.04.012] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 01/28/2023]
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Interaction of Temperature and Photoperiod Increases Growth and Oil Content in the Marine Microalgae Dunaliella viridis. PLoS One 2015; 10:e0127562. [PMID: 25992838 PMCID: PMC4437649 DOI: 10.1371/journal.pone.0127562] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/15/2015] [Indexed: 11/19/2022] Open
Abstract
Eukaryotic marine microalgae like Dunaliella spp. have great potential as a feedstock for liquid transportation fuels because they grow fast and can accumulate high levels of triacylgycerides with little need for fresh water or land. Their growth rates vary between species and are dependent on environmental conditions. The cell cycle, starch and triacylglycerol accumulation are controlled by the diurnal light:dark cycle. Storage compounds like starch and triacylglycerol accumulate in the light when CO2 fixation rates exceed the need of assimilated carbon and energy for cell maintenance and division during the dark phase. To delineate environmental effects, we analyzed cell division rates, metabolism and transcriptional regulation in Dunaliella viridis in response to changes in light duration and growth temperatures. Its rate of cell division was increased under continuous light conditions, while a shift in temperature from 25°C to 35°C did not significantly affect the cell division rate, but increased the triacylglycerol content per cell several-fold under continuous light. The amount of saturated fatty acids in triacylglycerol fraction was more responsive to an increase in temperature than to a change in the light regime. Detailed fatty acid profiles showed that Dunaliella viridis incorporated lauric acid (C12:0) into triacylglycerol after 24 hours under continuous light. Transcriptome analysis identified potential regulators involved in the light and temperature-induced lipid accumulation in Dunaliella viridis.
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36
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Cross FR, Umen JG. The Chlamydomonas cell cycle. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:370-392. [PMID: 25690512 PMCID: PMC4409525 DOI: 10.1111/tpj.12795] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 05/18/2023]
Abstract
The position of Chlamydomonas within the eukaryotic phylogeny makes it a unique model in at least two important ways: as a representative of the critically important, early-diverging lineage leading to plants; and as a microbe retaining important features of the last eukaryotic common ancestor (LECA) that has been lost in the highly studied yeast lineages. Its cell biology has been studied for many decades and it has well-developed experimental genetic tools, both classical (Mendelian) and molecular. Unlike land plants, it is a haploid with very few gene duplicates, making it ideal for loss-of-function genetic studies. The Chlamydomonas cell cycle has a striking temporal and functional separation between cell growth and rapid cell division, probably connected to the interplay between diurnal cycles that drive photosynthetic cell growth and the cell division cycle; it also exhibits a highly choreographed interaction between the cell cycle and its centriole-basal body-flagellar cycle. Here, we review the current status of studies of the Chlamydomonas cell cycle. We begin with an overview of cell-cycle control in the well-studied yeast and animal systems, which has yielded a canonical, well-supported model. We discuss briefly what is known about similarities and differences in plant cell-cycle control, compared with this model. We next review the cytology and cell biology of the multiple-fission cell cycle of Chlamydomonas. Lastly, we review recent genetic approaches and insights into Chlamydomonas cell-cycle regulation that have been enabled by a new generation of genomics-based tools.
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Affiliation(s)
| | - James G Umen
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
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37
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Kuwano K, Abe N, Nishi Y, Seno H, Nishihara GN, Iima M, Zachleder V. Growth and cell cycle of Ulva compressa (Ulvophyceae) under LED illumination. JOURNAL OF PHYCOLOGY 2014; 50:744-752. [PMID: 26988458 DOI: 10.1111/jpy.12207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/07/2014] [Indexed: 06/05/2023]
Abstract
The cell-cycle progression of Ulva compressa is diurnally gated at the G1 phase in accordance with light-dark cycles. The present study was designed to examine the spectral sensitivity of the G1 gating system. When blue, red, and green light-emitting diodes (LEDs) were used for illumination either alone or in combination, the cells divided under all illumination conditions, suggesting that all colors of light were able to open the G1 gate. Although blue light was most effective to open the G1 gate, red light alone or green light alone was also able to open the G1 gate even at irradiance levels lower than the light compensation point of each color. Occurrence of a period of no cell division in the course of a day suggested that the G1 gating system normally functioned as under ordinary illumination by cool-white fluorescent lamps. The rise of the proportion of blue light to green light resulted in increased growth rate. On the other hand, the growth rates did not vary regardless of the proportion of blue light to red light. These results indicate that the difference in growth rate due to light color resulted from the difference in photosynthetic efficiency of the colors of light. However, the growth rates significantly decreased under conditions without blue light. This result suggests that blue light mediates cell elongation and because the spectral sensitivity of the cell elongation regulating system was different from that of the G1 gating system, distinct photoreceptors are likely to mediate the two systems.
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Affiliation(s)
- Kazuyoshi Kuwano
- Graduate School of Science and Technology, Nagasaki University, Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Naoko Abe
- Graduate School of Science and Technology, Nagasaki University, Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Yukari Nishi
- Faculty of Fisheries, Nagasaki University, Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Hiromi Seno
- Faculty of Fisheries, Nagasaki University, Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Gregory N Nishihara
- Institute for East China Sea Research, Nagasaki University, Taira-machi, Nagasaki, 851-2213, Japan
| | - Masafumi Iima
- Faculty of Environmental Studies, Nagasaki University, Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Vilém Zachleder
- Laboratory of Cell Cycles of Algae, Institute of Microbiology, Academy of Sciences of the Czech Republic (ASCR), Opatovický mlýn, 37981, Třeboň, Czech Republic
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38
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Stirk WA, Bálint P, Tarkowská D, Novák O, Maróti G, Ljung K, Turečková V, Strnad M, Ordög V, van Staden J. Effect of light on growth and endogenous hormones in Chlorella minutissima (Trebouxiophyceae). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 79:66-76. [PMID: 24685518 DOI: 10.1016/j.plaphy.2014.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/04/2014] [Indexed: 05/28/2023]
Abstract
Plant growth regulators (PGRs) play an important role in mediating growth and stress responses in plants. Light influences PGRs concentrations in vascular plants. The effect of light on growth and endogenous PGR concentrations in microalgae was investigated in the present study. Chlorella minutissima MACC 360 was grown in 14:10 h light:dark (L:D), continuous dark (CD) and continuous dark with the addition of 5 g L(-1) glucose (CD + G) for 48 h. Cultures were synchronized in the L:D cultures, increasing in size during the light period and dividing during the dark period. C. minutissima cells did not increase in size or undergo cell division in CD cultures. In CD + G conditions, the cultures were no longer synchronized but did continue to increase in cell size and constantly underwent cell division although fewer cells divided than in the L:D cultures. Endogenous auxin and cytokinin concentrations increased and gibberellin concentrations decreased over time in the actively growing cultures (L:D and CD + G) but did not increase in the CD cultures. The largest increase in indole content was in the CD + G cultures while the L:D cultures had the largest cytokinin increase. Brassinosteroid concentrations decreased over time in all the cultures including those grown in CD conditions. Abscisic acid (ABA) concentrations were low and only increased in the CD cultures. These results show that endogenous PGRs were affected by the light regime and/or culture growth.
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Affiliation(s)
- W A Stirk
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa.
| | - P Bálint
- Institute of Plant Biology, Faculty of Agricultural and Food Sciences, University of West Hungary, H-9200 Mosonmagyaróvár, Hungary
| | - D Tarkowská
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - O Novák
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic; Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - G Maróti
- Hungarian Academy of Sciences, Biological Research Centre, Institute of Biochemistry, Temeszári krt. 62, H-6726 Szeged, Hungary
| | - K Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - V Turečková
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - M Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - V Ordög
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa; Institute of Plant Biology, Faculty of Agricultural and Food Sciences, University of West Hungary, H-9200 Mosonmagyaróvár, Hungary
| | - J van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa
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Bišová K, Zachleder V. Cell-cycle regulation in green algae dividing by multiple fission. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2585-602. [PMID: 24441762 DOI: 10.1093/jxb/ert466] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Green algae dividing by multiple fission comprise unrelated genera but are connected by one common feature: under optimal growth conditions, they can divide into more than two daughter cells. The number of daughter cells, also known as the division number, is relatively stable for most species and usually ranges from 4 to 16. The number of daughter cells is dictated by growth rate and is modulated by light and temperature. Green algae dividing by multiple fission can thus be used to study coordination of growth and progression of the cell cycle. Algal cultures can be synchronized naturally by alternating light/dark periods so that growth occurs in the light and DNA replication(s) and nuclear and cellular division(s) occur in the dark; synchrony in such cultures is almost 100% and can be maintained indefinitely. Moreover, the pattern of cell-cycle progression can be easily altered by differing growth conditions, allowing for detailed studies of coordination between individual cell-cycle events. Since the 1950s, green algae dividing by multiple fission have been studied as a unique model for cell-cycle regulation. Future sequencing of algal genomes will provide additional, high precision tools for physiological, taxonomic, structural, and molecular studies in these organisms.
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Affiliation(s)
- Kateřina Bišová
- Laboratory of Cell Cycles of Algae, Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81 Třeboň, Czech Republic
| | - Vilém Zachleder
- Laboratory of Cell Cycles of Algae, Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81 Třeboň, Czech Republic
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40
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Mao L, Verwoerd WS. Computational comparison of mediated current generation capacity of Chlamydomonas reinhardtii in photosynthetic and respiratory growth modes. J Biosci Bioeng 2014; 118:565-74. [PMID: 24875305 DOI: 10.1016/j.jbiosc.2014.04.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/16/2014] [Accepted: 04/28/2014] [Indexed: 11/18/2022]
Abstract
Chlamydomonas reinhardtii possesses many potential advantages to be exploited as a biocatalyst in microbial fuel cells (MFCs) for electricity generation. In the present study, we performed computational studies based on flux balance analysis (FBA) to probe the maximum potential of C. reinhardtii for current output and identify the metabolic mechanisms supporting a high current generation in three different cultivation conditions, i.e., heterotrophic, photoautotrophic and mixotrophic growth. The results showed that flux balance limitations allow the highest current output for C. reinhardtii in the mixotrophic growth mode (2.368 A/gDW), followed by heterotrophic growth (1.141 A/gDW) and photoautotrophic growth the lowest (0.7035 A/gDW). The significantly higher mediated electron transfer (MET) rate in the mixotrophic mode is in complete contrast to previous findings for a photosynthetic cyanobacterium, and was attributed to the fact that for C. reinhardtii the photophosphorylation improved the efficiency of converting the acetate into biomass and NADH production. Overall, the cytosolic NADH-dependent current production was mainly associated with five reactions in both mixotrophic and photoautotrophic nutritional modes, whereas four reactions participated in the heterotrophic mode. The mixotrophic and photoautotrophic metabolisms were alike and shared the same set of reactions for maximizing current production, whereas in the heterotrophic mode, the current production was additionally contributed by the metabolic activities in the two organelles: glyoxysome and chloroplast. In conclusion, C. reinhardtii has a potential to be exploited in MFCs of MET mode to produce a high current output.
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Affiliation(s)
- Longfei Mao
- Centre for Advanced Computational Solutions, Department of Molecular Biosciences, Lincoln University, Ellesmere Junction Road/Springs Road, Lincoln 7647, New Zealand.
| | - Wynand S Verwoerd
- Centre for Advanced Computational Solutions, Department of Molecular Biosciences, Lincoln University, Ellesmere Junction Road/Springs Road, Lincoln 7647, New Zealand
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Shelton DE, Michod RE. Group Selection and Group Adaptation During a Major Evolutionary Transition: Insights from the Evolution of Multicellularity in the Volvocine Algae. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s13752-014-0159-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Valledor L, Furuhashi T, Recuenco-Muñoz L, Wienkoop S, Weckwerth W. System-level network analysis of nitrogen starvation and recovery in Chlamydomonas reinhardtii reveals potential new targets for increased lipid accumulation. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:171. [PMID: 25663847 PMCID: PMC4320484 DOI: 10.1186/s13068-014-0171-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 11/17/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Nitrogen starvation is known to cause drastic alterations in physiology and metabolism leading to the accumulation of lipid bodies in many microalgae, and it thus presents an important alternative for biofuel production. However, despite the importance of this process, the molecular mechanisms that mediate the metabolic remodeling induced by N starvation and especially by stress recovery are still poorly understood, and new candidates for bioengineering are needed to make this process useful for biofuel production. RESULTS We have studied the molecular changes involved in the adaptive mechanisms to N starvation and full recovery of the vegetative cells in the microalga Chlamydomonas reinhardtii during a four-day time course. High throughput mass spectrometry was employed to integrate the proteome and the metabolome with physiological changes. N starvation led to an accumulation of oil bodies and reduced Fv/Fm.. Distinct enzymes potentially participating in the carbon-concentrating mechanism (CAH7, CAH8, PEPC1) are strongly accumulated. The membrane composition is changed, as indicated by quantitative lipid profiles. A reprogramming of protein biosynthesis was observed by increased levels of cytosolic ribosomes, while chloroplastidic were dramatically reduced. Readdition of N led to, the identification of early responsive proteins mediating stress recovery, indicating their key role in regaining and sustaining normal vegetative growth. Analysis of the data with multivariate correlation analysis, Granger causality, and sparse partial least square (sPLS) provided a functional network perspective of the molecular processes. Cell growth and N metabolism were clearly linked by the branched chain amino acids, suggesting an important role in this stress. Lipid accumulation was also tightly correlated to the COP II protein, involved in vesicle and lysosome coating, and a major lipid droplet protein. This protein, together with other key proteins mediating signal transduction and adaption (BRI1, snRKs), constitute a series of new metabolic and regulatory targets. CONCLUSIONS This work not only provides new insights and corrects previous models by analyzing a complex dataset, but also increases our biochemical understanding of the adaptive mechanisms to N starvation in Chlamydomonas, pointing to new bioengineering targets for increased lipid accumulation, a key step for a sustainable and profitable microalgae-based biofuel production.
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Affiliation(s)
- Luis Valledor
- />Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
- />Cyanoteam, Global Change Research Center-Czechglobe, Academy of Sciences of the Czech Republic, Belidla 4, 603 00 Brno, Czech Republic
- />Present address: Plant Physiology, University of Oviedo, Catedrático Rodrígo Uría s/n, E-33006 Oviedo, Spain
| | - Takeshi Furuhashi
- />Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Luis Recuenco-Muñoz
- />Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Stefanie Wienkoop
- />Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Wolfram Weckwerth
- />Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
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The synchronized cell cycle of Neochloris oleoabundans and its influence on biomass composition under constant light conditions. ALGAL RES 2013. [DOI: 10.1016/j.algal.2013.09.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Le Borgne F, Pruvost J. Investigation and modeling of biomass decay rate in the dark and its potential influence on net productivity of solar photobioreactors for microalga Chlamydomonas reinhardtii and cyanobacterium Arthrospira platensis. BIORESOURCE TECHNOLOGY 2013; 138:271-276. [PMID: 23619140 DOI: 10.1016/j.biortech.2013.03.056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 03/01/2013] [Accepted: 03/09/2013] [Indexed: 06/02/2023]
Abstract
Biomass decay rate (BDR) in the dark was investigated for Chlamydomonas reinhardtii (microalga) and Arthrospira platensis (cyanobacterium). A specific setup based on a torus photobioreactor with online gas analysis was validated, enabling us to follow the time course of the specific BDR using oxygen monitoring and mass balance. Various operating parameters that could limit respiration rates, such as culture temperature and oxygen deprivation, were then investigated. C. reinhardtii was found to present a higher BDR in the dark than A. platensis, illustrating here the difference between eukaryotic and prokaryotic cells. In both cases, temperature proved an influential parameter, and the Arrhenius law was found to efficiently relate specific BDR to culture temperature. The utility of decreasing temperature at night to increase biomass productivity in a solar photobioreactor is also illustrated.
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Affiliation(s)
- François Le Borgne
- Université de Nantes, CNRS, GEPEA UMR-CNRS 6144, boulevard de l'Université, CRTT-BP 406, 44602 Saint-Nazaire Cedex, France.
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Garz A, Sandmann M, Rading M, Ramm S, Menzel R, Steup M. Cell-to-cell diversity in a synchronized Chlamydomonas culture as revealed by single-cell analyses. Biophys J 2013; 103:1078-86. [PMID: 23009858 DOI: 10.1016/j.bpj.2012.07.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/08/2012] [Accepted: 07/05/2012] [Indexed: 11/25/2022] Open
Abstract
In a synchronized photoautotrophic culture of Chlamydomonas reinhardtii, cell size, cell number, and the averaged starch content were determined throughout the light-dark cycle. For single-cell analyses, the relative cellular starch was quantified by measuring the second harmonic generation (SHG). In destained cells, amylopectin essentially represents the only biophotonic structure. As revealed by various validation procedures, SHG signal intensities are a reliable relative measure of the cellular starch content. During photosynthesis-driven starch biosynthesis, synchronized Chlamydomonas cells possess an unexpected cell-to-cell diversity both in size and starch content, but the starch-related heterogeneity largely exceeds that of size. The cellular volume, starch content, and amount of starch/cell volume obey lognormal distributions. Starch degradation was initiated by inhibiting the photosynthetic electron transport in illuminated cells or by darkening. Under both conditions, the averaged rate of starch degradation is almost constant, but it is higher in illuminated than in darkened cells. At the single-cell level, rates of starch degradation largely differ but are unrelated to the initial cellular starch content. A rate equation describing the cellular starch degradation is presented. SHG-based three-dimensional reconstructions of Chlamydomonas cells containing starch granules are shown.
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Affiliation(s)
- Andreas Garz
- Institute of Physics and Astronomy, Department of Photonics, University of Potsdam, Potsdam-Golm, Germany
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Vítová M, Bišová K, Hlavová M, Kawano S, Zachleder V, Cížková M. Chlamydomonas reinhardtii: duration of its cell cycle and phases at growth rates affected by temperature. PLANTA 2011; 234:599-608. [PMID: 21573815 DOI: 10.1007/s00425-011-1427-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 04/28/2011] [Indexed: 05/30/2023]
Abstract
Synchronized cultures of the green alga Chlamydomonas reinhardtii were grown photoautotrophically under a wide range of environmental conditions including temperature (15-37 °C), different mean light intensities (132, 150, 264 μmol m⁻² s⁻¹), different illumination regimes (continuous illumination or alternation of light/dark periods of different durations), and culture methods (batch or continuous culture regimes). These variable experimental approaches were chosen in order to assess the role of temperature in the timing of cell division, the length of the cell cycle and its pre- and post-commitment phases. Analysis of the effect of temperature, from 15 to 37 °C, on synchronized cultures showed that the length of the cell cycle varied markedly from times as short as 14 h to as long as 36 h. We have shown that the length of the cell cycle was proportional to growth rate under any given combination of growth conditions. These findings were supported by the determination of the temperature coefficient (Q₁₀), whose values were above the level expected for temperature-compensated processes. The data presented here show that cell cycle duration in C. reinhardtii is a function of growth rate and is not controlled by a temperature independent endogenous timer or oscillator, including a circadian one.
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Affiliation(s)
- Milada Vítová
- Laboratory of Cell Cycles of Algae, Institute of Microbiology, Academy of Sciences of the Czech Republic (ASCR), Opatovický Mlýn, 37981 Třeboň, Czech Republic
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