101
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Chukhutsina V, Büchel C, van Amerongen H. Variations in the first steps of photosynthesis for the diatom Cyclotella meneghiniana grown under different light conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:10-8. [DOI: 10.1016/j.bbabio.2012.09.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 09/19/2012] [Accepted: 09/25/2012] [Indexed: 12/14/2022]
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102
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Napoléon C, Claquin P. Multi-parametric relationships between PAM measurements and carbon incorporation, an in situ approach. PLoS One 2012; 7:e40284. [PMID: 22911698 PMCID: PMC3401225 DOI: 10.1371/journal.pone.0040284] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 06/04/2012] [Indexed: 11/18/2022] Open
Abstract
Primary production (PP) in the English Channel was measured using (13)C uptake and compared to the electron transport rate (ETR) measured using PAM (pulse amplitude modulated fluorometer). The relationship between carbon incorporation (P(obs)) and ETR was not linear but logarithmic. This result can be explained by alternative electron sinks at high irradiance which protect the phytoplankton from photoinhibition. A multi-parametric model was developed to estimate PP by ETR. This approach highlighted the importance of taking physicochemical parameters like incident light and nutrient concentrations into account. The variation in the ETR/P(obs) ratio as a function of the light revealed different trends which were characterized by three parameters (R(max), the maximum value of ETR/P(obs); E(Rmax), the light intensity at which R(max) is measured; γ the initial slope of the curve). Based on the values of these three parameters, data were divided into six groups which were highly dependent on the seasons and on the physicochemical conditions. Using the multi-parametric model which we defined by P(obs) and ETR measurements at low frequencies, the high frequency measurements of ETR enabled us to estimate the primary production capacity between November 2009 and December 2010 at high temporal and spatial scales.
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Affiliation(s)
- Camille Napoléon
- Université de Caen Basse-Normandie, BIOMEA FRE3484 CNRS, Caen, France
- CNRS INEE, FRE3484 BIOMEA, Caen, France
- IFREMER, Laboratoire Environnement Ressources de Normandie, Avenue du Général de Gaulle, Port-en-Bessin, France
| | - Pascal Claquin
- Université de Caen Basse-Normandie, BIOMEA FRE3484 CNRS, Caen, France
- CNRS INEE, FRE3484 BIOMEA, Caen, France
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103
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Lavaud J, Materna AC, Sturm S, Vugrinec S, Kroth PG. Silencing of the violaxanthin de-epoxidase gene in the diatom Phaeodactylum tricornutum reduces diatoxanthin synthesis and non-photochemical quenching. PLoS One 2012; 7:e36806. [PMID: 22629333 PMCID: PMC3356336 DOI: 10.1371/journal.pone.0036806] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 04/13/2012] [Indexed: 11/19/2022] Open
Abstract
Diatoms are a major group of primary producers ubiquitous in all aquatic ecosystems. To protect themselves from photooxidative damage in a fluctuating light climate potentially punctuated with regular excess light exposures, diatoms have developed several photoprotective mechanisms. The xanthophyll cycle (XC) dependent non-photochemical chlorophyll fluorescence quenching (NPQ) is one of the most important photoprotective processes that rapidly regulate photosynthesis in diatoms. NPQ depends on the conversion of diadinoxanthin (DD) into diatoxanthin (DT) by the violaxanthin de-epoxidase (VDE), also called DD de-epoxidase (DDE). To study the role of DDE in controlling NPQ, we generated transformants of P. tricornutum in which the gene (Vde/Dde) encoding for DDE was silenced. RNA interference was induced by genetic transformation of the cells with plasmids containing either short (198 bp) or long (523 bp) antisense (AS) fragments or, alternatively, with a plasmid mediating the expression of a self-complementary hairpin-like construct (inverted repeat, IR). The silencing approaches generated diatom transformants with a phenotype clearly distinguishable from wildtype (WT) cells, i.e. a lower degree as well as slower kinetics of both DD de-epoxidation and NPQ induction. Real-time PCR based quantification of Dde transcripts revealed differences in transcript levels between AS transformants and WT cells but also between AS and IR transformants, suggesting the possible presence of two different gene silencing mediating mechanisms. This was confirmed by the differential effect of the light intensity on the respective silencing efficiency of both types of transformants. The characterization of the transformants strengthened some of the specific features of the XC and NPQ and confirmed the most recent mechanistic model of the DT/NPQ relationship in diatoms.
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Affiliation(s)
- Johann Lavaud
- Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
- UMR7266 ‘LIENSs,’ CNRS/University of La Rochelle, Institute for Coastal and Environmental Research, La Rochelle, France
| | - Arne C. Materna
- Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
| | - Sabine Sturm
- Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
- * E-mail:
| | - Sascha Vugrinec
- Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
| | - Peter G. Kroth
- Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
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104
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Consequences of the presence of 24-epibrassinolide, on cultures of a diatom, Asterionella formosa. Biochimie 2012; 94:1213-20. [DOI: 10.1016/j.biochi.2012.02.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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105
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Beer A, Juhas M, Büchel C. INFLUENCE OF DIFFERENT LIGHT INTENSITIES AND DIFFERENT IRON NUTRITION ON THE PHOTOSYNTHETIC APPARATUS IN THE DIATOM CYCLOTELLA MENEGHINIANA (BACILLARIOPHYCEAE)(1). JOURNAL OF PHYCOLOGY 2011; 47:1266-73. [PMID: 27020350 DOI: 10.1111/j.1529-8817.2011.01060.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The diatom Cyclotella meneghiniana Kütz. (SAG 1020-a) was cultured under high-light (HL) and low-light (LL) conditions with either high (12 μM) or low (1 μM) iron in the media. Changes in cell morphology, especially cell volume and chloroplast size, were observed in cells grown under low iron. In contrast, HL had a much stronger influence on the photosynthetic apparatus. PSII function was unimpaired under lowered iron supply, but its quantum efficiency and reoxidation rate were reduced under HL conditions. As reported before, HL induced changes in antenna polypeptide composition. Especially the amount of Fcp6, an antenna protein related to LI818 and known to be involved in photoprotection, was increased under HL but was significantly reduced under lowered iron. The diatoxanthin content correlated with the amount of Fcp6 in isolated FCPa antenna complexes and was thus increased under HL and reduced under low iron as well. While the diatoxanthin (Dt) content of whole cells was enhanced under HL, no decrease was observed under lowered iron supply, ruling out the possibility that the decreased amounts in FCPa were due to a hampered diadinoxanthin de-epoxidase activity under these conditions. Thus, diatoxanthin not bound to FCPa has to be responsible for protection under the slight reduction in iron supply used here.
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Affiliation(s)
- Anja Beer
- Institute of Molecular Bioscience, University of Frankfurt, Siesmayerstr. 70, 60323 Frankfurt, Germany
| | - Matthias Juhas
- Institute of Molecular Bioscience, University of Frankfurt, Siesmayerstr. 70, 60323 Frankfurt, Germany
| | - Claudia Büchel
- Institute of Molecular Bioscience, University of Frankfurt, Siesmayerstr. 70, 60323 Frankfurt, Germany
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106
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Whitney LP, Lins JJ, Hughes MP, Wells ML, Chappell PD, Jenkins BD. Characterization of putative iron responsive genes as species-specific indicators of iron stress in thalassiosiroid diatoms. Front Microbiol 2011; 2:234. [PMID: 22275908 PMCID: PMC3223615 DOI: 10.3389/fmicb.2011.00234] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 11/09/2011] [Indexed: 11/13/2022] Open
Abstract
Iron (Fe) availability restricts diatom growth and primary production in large areas of the oceans. It is a challenge to assess the bulk Fe nutritional health of natural diatom populations, since species can differ in their physiological and molecular responses to Fe limitation. We assayed expression of selected genes in diatoms from the Thalassiosira genus to assess their potential utility as species-specific molecular markers to indicate Fe status in natural diatom assemblages. In this study, we compared the expression of the photosynthetic genes encoding ferredoxin (a Fe-requiring protein) and flavodoxin (a Fe-free protein) in culture experiments with Fe replete and Fe stressed Thalassiosira pseudonana (CCMP 1335) isolated from coastal waters and Thalassiosira weissflogii (CCMP 1010) isolated from the open ocean. In T. pseudonana, expression of flavodoxin and ferredoxin genes were not sensitive to Fe status but were found to display diel periodicities. In T. weissflogii, expression of flavodoxin was highly responsive to iron levels and was only detectable when cultures were Fe limited. Flavodoxin genes have been duplicated in most diatoms with available genome data and we show that T. pseudonana has lost its copy related to the Fe-responsive copy in T. weissflogii. We also examined the expression of genes for a putative high affinity, copper (Cu)-dependent Fe uptake system in T. pseudonana. Our results indicate that genes encoding putative Cu transporters, a multi-Cu oxidase, and a Fe reductase are not linked to Fe status. The expression of a second putative Fe reductase increased in Fe limited cultures, but this gene was also highly expressed in Fe replete cultures, indicating it may not be a useful marker in the field. Our findings highlight that Fe metabolism may differ among diatoms even within a genus and show a need to validate responses in different species as part of the development pipeline for genetic markers of Fe status in field populations.
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Affiliation(s)
- LeAnn P. Whitney
- Department of Cell and Molecular Biology, University of Rhode IslandKingston, RI, USA
| | - Jeremy J. Lins
- Department of Cell and Molecular Biology, University of Rhode IslandKingston, RI, USA
| | - Margaret P. Hughes
- Institute of Marine Sciences, University of CaliforniaSanta Cruz, CA, USA
| | - Mark L. Wells
- Institute of Marine Sciences, University of CaliforniaSanta Cruz, CA, USA
- School of Marine Sciences, University of MaineOrono, ME, USA
| | - P. Dreux Chappell
- Department of Cell and Molecular Biology, University of Rhode IslandKingston, RI, USA
| | - Bethany D. Jenkins
- Department of Cell and Molecular Biology, University of Rhode IslandKingston, RI, USA
- Graduate School of Oceanography, University of Rhode IslandNarragansett, RI, USA
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107
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Allen AE, Moustafa A, Montsant A, Eckert A, Kroth PG, Bowler C. Evolution and functional diversification of fructose bisphosphate aldolase genes in photosynthetic marine diatoms. Mol Biol Evol 2011; 29:367-79. [PMID: 21903677 PMCID: PMC3245544 DOI: 10.1093/molbev/msr223] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Diatoms and other chlorophyll-c containing, or chromalveolate, algae are among the most productive and diverse phytoplankton in the ocean. Evolutionarily, chlorophyll-c algae are linked through common, although not necessarily monophyletic, acquisition of plastid endosymbionts of red as well as most likely green algal origin. There is also strong evidence for a relatively high level of lineage-specific bacterial gene acquisition within chromalveolates. Therefore, analyses of gene content and derivation in chromalveolate taxa have indicated particularly diverse origins of their overall gene repertoire. As a single group of functionally related enzymes spanning two distinct gene families, fructose 1,6-bisphosphate aldolases (FBAs) illustrate the influence on core biochemical pathways of specific evolutionary associations among diatoms and other chromalveolates with various plastid-bearing and bacterial endosymbionts. Protein localization and activity, gene expression, and phylogenetic analyses indicate that the pennate diatom Phaeodactylum tricornutum contains five FBA genes with very little overall functional overlap. Three P. tricornutum FBAs, one class I and two class II, are plastid localized, and each appears to have a distinct evolutionary origin as well as function. Class I plastid FBA appears to have been acquired by chromalveolates from a red algal endosymbiont, whereas one copy of class II plastid FBA is likely to have originated from an ancient green algal endosymbiont. The other copy appears to be the result of a chromalveolate-specific gene duplication. Plastid FBA I and chromalveolate-specific class II plastid FBA are localized in the pyrenoid region of the chloroplast where they are associated with β-carbonic anhydrase, which is known to play a significant role in regulation of the diatom carbon concentrating mechanism. The two pyrenoid-associated FBAs are distinguished by contrasting gene expression profiles under nutrient limiting compared with optimal CO2 fixation conditions, suggestive of a distinct specialized function for each. Cytosolically localized FBAs in P. tricornutum likely play a role in glycolysis and cytoskeleton function and seem to have originated from the stramenopile host cell and from diatom-specific bacterial gene transfer, respectively.
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Affiliation(s)
- Andrew E Allen
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supéreure, CNRS UMR8186 INSERM U1024, Ecole Normale Supérieure, Paris, France
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108
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Wu H, Cockshutt AM, McCarthy A, Campbell DA. Distinctive photosystem II photoinactivation and protein dynamics in marine diatoms. PLANT PHYSIOLOGY 2011; 156:2184-95. [PMID: 21617029 PMCID: PMC3149953 DOI: 10.1104/pp.111.178772] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 05/24/2011] [Indexed: 05/17/2023]
Abstract
Diatoms host chlorophyll a/c chloroplasts distinct from green chloroplasts. Diatoms now dominate the eukaryotic oceanic phytoplankton, in part through their exploitation of environments with variable light. We grew marine diatoms across a range of temperatures and then analyzed their PSII function and subunit turnover during an increase in light to mimic an upward mixing event. The small diatom Thalassiosira pseudonana initially responds to increased photoinactivation under blue or white light with rapid acceleration of the photosystem II (PSII) repair cycle. Increased red light provoked only modest PSII photoinactivation but triggered a rapid clearance of a subpool of PsbA. Furthermore, PsbD and PsbB content was greater than PsbA content, indicating a large pool of partly assembled PSII repair cycle intermediates lacking PsbA. The initial replacement rates for PsbD (D2) were, surprisingly, comparable to or higher than those for PsbA (D1), and even the supposedly stable PsbB (CP47) dropped rapidly upon the light shift, showing a novel aspect of rapid protein subunit turnover in the PSII repair cycle in small diatoms. Under sustained high light, T. pseudonana induces sustained nonphotochemical quenching, which correlates with stabilization of PSII function and the PsbA pool. The larger diatom Coscinodiscus radiatus showed generally similar responses but had a smaller allocation of PSII complexes relative to total protein content, with nearly equal stiochiometries of PsbA and PsbD subunits. Fast turnover of multiple PSII subunits, pools of PSII repair cycle intermediates, and photoprotective induction of nonphotochemical quenching are important interacting factors, particularly for small diatoms, to withstand and exploit high, fluctuating light.
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Affiliation(s)
| | | | | | - Douglas A. Campbell
- Biology Department, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G7 (H.W., D.A.C.); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian 361005, China (H.W.); Chemistry and Biochemistry Department, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8 (A.M.C., A.M.)
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109
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Blache U, Jakob T, Su W, Wilhelm C. The impact of cell-specific absorption properties on the correlation of electron transport rates measured by chlorophyll fluorescence and photosynthetic oxygen production in planktonic algae. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:801-8. [PMID: 21571541 DOI: 10.1016/j.plaphy.2011.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 04/20/2011] [Indexed: 05/01/2023]
Abstract
Photosynthesis-irradiance (P-E)-curves describe the photosynthetic performance of autotrophic organisms. From these P-E-curves the photosynthetic parameters α-slope, P(max), and E(k) can be deduced which are often used to characterize and to compare different organisms or organisms in acclimation to different environmental conditions. Particularly, for in situ-measurements of P-E curves of phytoplankton the analysis of variable chlorophyll fluorescence proved its potential as a sensitive and rapid method. By using Chlorella vulgaris (Trebouxiophyceae), Nannochloropsis salina (Eustigmatophyceae), Skeletonema costatum and Cyclotella meneghiniana (Bacillariophyceae), the present study investigated the influence of cellular bio-optical properties on the correlation of the photosynthetic parameters derived from fluorescence-based P-E-curves with photosynthetic parameters obtained from the measurement of oxygen evolution. It is demonstrated that small planktonic algae show a wide range of cellular absorptivity which was subject to species-specifity, growth stage and environmental conditions, e.g. nutrient limitation. This variability in bio-optical properties resulted in a great deviation of relative electron transport rates (rETRs) from oxygen-based photosynthesis rates. Thus, the photosynthetic parameters α-slope and P(max) derived from rETRs strongly depend on the specific cellular absorptivity and cannot be used to compare the photosynthetic performance of cells with different optical properties. However, it was shown that E(k) is independent of cellular absorptivity and could be used to compare samples with unknown optical properties.
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Affiliation(s)
- Ulrich Blache
- Dept. Plant Physiology, Biology I, University of Leipzig, Johannisallee 21-23, D-04103 Leipzig, Germany
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110
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Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering. Biochem J 2011; 436:225-30. [PMID: 21473741 DOI: 10.1042/bj20110180] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique reveals light-induced reversible reorganizations in the seconds-to-minutes time scale, which appear to be associated with functional changes in vivo.
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111
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Palmucci M, Ratti S, Giordano M. ECOLOGICAL AND EVOLUTIONARY IMPLICATIONS OF CARBON ALLOCATION IN MARINE PHYTOPLANKTON AS A FUNCTION OF NITROGEN AVAILABILITY: A FOURIER TRANSFORM INFRARED SPECTROSCOPY APPROACH(1). JOURNAL OF PHYCOLOGY 2011; 47:313-323. [PMID: 27021863 DOI: 10.1111/j.1529-8817.2011.00963.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An imbalance in the cellular C:N ratio may appreciably affect C allocation in algal cells. The consequences of these rearrangements of cellular pools on cell energetics, ecological fitness, and evolutionary trajectories are little known, although they are expected to be substantial. We investigated the fate of C in 11 microalgae cultured semicontinuously at three [NO3 (-) ] and constant pCO2 . We developed a new computational method for the semiquantitative use of Fourier transform infrared (FTIR) spectroscopy data for the determination of macromolecular composition. No obvious relationship was observed between the taxonomy and the allocation strategies adopted by the 11 species considered in this study. Not all species responded to a lower N availability by accumulating lipids or carbohydrates: Dunaliella parva W. Lerche and Thalassiosira pseudonana Hasle et Heimdal were homeostatic with respect to organic cell composition. A hyperbolic dependence of the lipid concentration from cell volume was observed. The level of reduction of organic constituents of green algae was parabolically related to size and was modulated in response to changes in N availability; the same was not true for the species bearing a "red" chloroplast. The above observations are discussed with respect to phytoplankton species composition and palatability for grazers, oleogenesis, and overall cell energetics.
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Affiliation(s)
- Matteo Palmucci
- Laboratorio di Fisiologia delle Alghe, Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Simona Ratti
- Laboratorio di Fisiologia delle Alghe, Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Mario Giordano
- Laboratorio di Fisiologia delle Alghe, Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
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112
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Wilhelm C, Selmar D. Energy dissipation is an essential mechanism to sustain the viability of plants: The physiological limits of improved photosynthesis. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:79-87. [PMID: 20800930 DOI: 10.1016/j.jplph.2010.07.012] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 05/29/2023]
Abstract
In bright sunlight photosynthetic activity is limited by the enzymatic machinery of carbon dioxide assimilation. This supererogation of energy can be easily visualized by the significant increases of photosynthetic activity under high CO(2) conditions or other metabolic strategies which can increase the carbon flux from CO(2) to metabolic pools. However, even under optimal CO(2) conditions plants will provide much more NADPH+H(+) and ATP that are required for the actual demand, yielding in a metabolic situation, in which no reducible NADP(+) would be available. As a consequence, excited chlorophylls can activate oxygen to its singlet state or the photosynthetic electrons can be transferred to oxygen, producing highly active oxygen species such as the superoxide anion, hydroxyl radicals and hydrogen peroxide. All of them can initiate radical chain reactions which degrade proteins, pigments, lipids and nucleotides. Therefore, the plants have developed protection and repair mechanism to prevent photodamage and to maintain the physiological integrity of metabolic apparatus. The first protection wall is regulatory energy dissipation on the level of the photosynthetic primary reactions by the so-called non-photochemical quenching. This dissipative pathway is under the control of the proton gradient generated by the electron flow and the xanthophyll cycle. A second protection mechanism is the effective re-oxidation of the reduction equivalents by so-called "alternative electron cycling" which includes the water-water cycle, the photorespiration, the malate valve and the action of antioxidants. The third system of defence is the repair of damaged components. Therefore, plants do not suffer from energy shortage, but instead they have to invest in proteins and cellular components which protect the plants from potential damage by the supererogation of energy. Under this premise, our understanding and evaluation for certain energy dissipating processes such as non-photochemical quenching or photorespiration appear in a quite new perspective, especially when discussing strategies to improve the solar energy conversion into plant biomass.
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Affiliation(s)
- Christian Wilhelm
- Institut für Biologie I, Universität Leipzig, Johannisallee 21-23, Leipzig, Germany.
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113
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Perez-Garcia O, Escalante FME, de-Bashan LE, Bashan Y. Heterotrophic cultures of microalgae: metabolism and potential products. WATER RESEARCH 2011; 45:11-36. [PMID: 20970155 DOI: 10.1016/j.watres.2010.08.037] [Citation(s) in RCA: 695] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/09/2010] [Accepted: 08/20/2010] [Indexed: 05/05/2023]
Abstract
This review analyzes the current state of a specific niche of microalgae cultivation; heterotrophic growth in the dark supported by a carbon source replacing the traditional support of light energy. This unique ability of essentially photosynthetic microorganisms is shared by several species of microalgae. Where possible, heterotrophic growth overcomes major limitations of producing useful products from microalgae: dependency on light which significantly complicates the process, increase costs, and reduced production of potentially useful products. As a general role, and in most cases, heterotrophic cultivation is far cheaper, simpler to construct facilities, and easier than autotrophic cultivation to maintain on a large scale. This capacity allows expansion of useful applications from diverse species that is now very limited as a result of elevated costs of autotrophy; consequently, exploitation of microalgae is restricted to small volume of high-value products. Heterotrophic cultivation may allow large volume applications such as wastewater treatment combined, or separated, with production of biofuels. In this review, we present a general perspective of the field, describing the specific cellular metabolisms involved and the best-known examples from the literature and analyze the prospect of potential products from heterotrophic cultures.
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Affiliation(s)
- Octavio Perez-Garcia
- Environmental Microbiology Group, Northwestern Center for Biological Research, Mar Bermejo 195, Col Playa Palo de Santa Rita, La Paz, BCS 23090, Mexico
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114
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Lepetit B, Volke D, Gilbert M, Wilhelm C, Goss R. Evidence for the existence of one antenna-associated, lipid-dissolved and two protein-bound pools of diadinoxanthin cycle pigments in diatoms. PLANT PHYSIOLOGY 2010; 154:1905-20. [PMID: 20935178 PMCID: PMC2996015 DOI: 10.1104/pp.110.166454] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 10/07/2010] [Indexed: 05/18/2023]
Abstract
We studied the localization of diadinoxanthin cycle pigments in the diatoms Cyclotella meneghiniana and Phaeodactylum tricornutum. Isolation of pigment protein complexes revealed that the majority of high-light-synthesized diadinoxanthin and diatoxanthin is associated with the fucoxanthin chlorophyll protein (FCP) complexes. The characterization of intact cells, thylakoid membranes, and pigment protein complexes by absorption and low-temperature fluorescence spectroscopy showed that the FCPs contain certain amounts of protein-bound diadinoxanthin cycle pigments, which are not significantly different in high-light and low-light cultures. The largest part of high-light-formed diadinoxanthin cycle pigments, however, is not bound to antenna apoproteins but located in a lipid shield around the FCPs, which is copurified with the complexes. This lipid shield is primarily composed of the thylakoid membrane lipid monogalactosyldiacylglycerol. We also show that the photosystem I (PSI) fraction contains a tightly connected FCP complex that is enriched in protein-bound diadinoxanthin cycle pigments. The peripheral FCP and the FCP associated with PSI are composed of different apoproteins. Tandem mass spectrometry analysis revealed that the peripheral FCP is composed mainly of the light-harvesting complex protein Lhcf and also significant amounts of Lhcr. The PSI fraction, on the other hand, shows an enrichment of Lhcr proteins, which are thus responsible for the diadinoxanthin cycle pigment binding. The existence of lipid-dissolved and protein-bound diadinoxanthin cycle pigments in the peripheral antenna and in PSI is discussed with respect to different specific functions of the xanthophylls.
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115
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Membrane potential is involved in regulation of photosynthetic reactions in the marine diatom Thalassiosira weissflogii. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2010; 102:169-73. [PMID: 21131210 DOI: 10.1016/j.jphotobiol.2010.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 11/10/2010] [Accepted: 11/11/2010] [Indexed: 10/18/2022]
Abstract
High-intensity Chl fluorescence transients (OJIP transients) and light-induced kinetics of the delayed light emission were measured in diatom microalga Thalassiosira weissflogii in the presence of various uncouplers and photosynthetic inhibitors. The I step in the OJIP transients in T. weissflogii was essentially reduced or completely absent but was restored in the presence of uncouplers valinomycin, FCCP, and nigericin. Moreover, valinomycin enhanced ΔpH-dependent non-photochemical fluorescence quenching following the OJIP rise. In the presence of valinomycin, the transthylakoid membrane potential was significantly inhibited as evaluated by measurements of the delayed light emission. The results suggest a membrane potential control of the fluorescence yield in T. weissflogii. Possible mechanisms underlying the observed effects of uncouplers are discussed.
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116
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Rosello Sastre R, Posten C. Die vielfältige Anwendung von Mikroalgen als nachwachsende Rohstoffe. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201000124] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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117
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Bertrand M. Carotenoid biosynthesis in diatoms. PHOTOSYNTHESIS RESEARCH 2010; 106:89-102. [PMID: 20734232 DOI: 10.1007/s11120-010-9589-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 07/24/2010] [Indexed: 05/20/2023]
Abstract
Diatoms are ubiquitous and constitute an important group of the phytoplankton community having a major contribution to the total marine primary production. These microalgae exhibit a characteristic golden-brown colour due to a high amount of the xanthophyll fucoxanthin that plays a major role in the light-harvesting complex of photosystems. In the water column, diatoms are exposed to light intensities that vary quickly from lower to higher values. Xanthophyll cycles prevent photodestruction of the cells in excessive light intensities. In diatoms, the diadinoxanthin-diatoxanthin cycle is the most important short-term photoprotective mechanism. If the biosynthetic pathways of chloroplast pigments have been extensively studied in higher plants and green algae, the research on carotenoid biosynthesis in diatoms is still in its infancy. In this study, the data on the biosynthetic pathway of diatom carotenoids are reviewed. The early steps occur through the 2-C-methyl-D: -erythritol 4-phosphate (MEP) pathway. Then a hypothetical pathway is suggested from dimethylallyl diphosphate (DMAPP) and isopentenyl pyrophosphate (IPP). Most of the enzymes of the pathway have not been so far isolated from diatoms, but candidate genes for each of them were identified using protein similarity searches of genomic data.
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Affiliation(s)
- Martine Bertrand
- MiMeTox, National Institute for Marine Sciences and Techniques, CNAM, BP 324, 50103 Cherbourg-Octeville Cedex, France.
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118
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Raven JA. Inorganic carbon acquisition by eukaryotic algae: four current questions. PHOTOSYNTHESIS RESEARCH 2010; 106:123-34. [PMID: 20524069 DOI: 10.1007/s11120-010-9563-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Accepted: 05/17/2010] [Indexed: 05/18/2023]
Abstract
The phylogenetically and morphologically diverse eukaryotic algae are typically oxygenic photolithotrophs. They have a diversity of incompletely understood mechanisms of inorganic carbon acquisition: this article reviews four areas where investigations continue. The first topic is diffusive CO(2) entry. Most eukaryotic algae, like all cyanobacteria, have inorganic carbon concentrating mechanisms (CCMs). The ancestral condition was presumably the absence of a CCM, i.e. diffusive CO(2) entry, as found in a small minority of eukaryotic algae today; however, it is likely that, as is found in several cases, this condition is due to a loss of a CCM. There are a number of algae which are in various respects intermediate between diffusive CO(2) entry and occurrence of a CCM: further study is needed on this aspect. A second topic is the nature of cyanelles and their role in inorganic carbon assimilation. The cyanelles (plastids) of the euglyphid amoeba Paulinella have been acquired relatively recently by endosymbiosis with genetic integration of an α-cyanobacterium with a Form 1A Rubisco. The α-carboxysomes in the cyanelles are presumably involved in a CCM, but further investigation is needed.Also called cyanelles are the plastids of glaucocystophycean algae, but is it now clear that these were derived from the β-cyanobacterial ancestor of all plastids other than that of Paulinella. The resemblances of the central body of the cyanelles of glaucocystophycean algae to carboxysomes may not reflect derivation from cyanobacterial β-carboxysomes; although it is clear that these algae have CCMs but these are now well characterized. The other two topics concern CCMs in other eukaryotic algae; these CCMs arose polyphyletically and independently of the cyanobacterial CCMs. It is generally believed that eukaryotic algal, like cyanobacterial, CCMs are based on active transport of an inorganic carbon species and/or protons, and they have C(3) biochemistry. This is the case for the organism considered as the third topic, i.e. Chlamydomonas reinhardtii, the eukaryotic alga with the best understood CCM. This CCM involves HCO(3)(-) conversion to CO(2) in the thylakoid lumen so the external inorganic carbon must cross four membranes in series with a final CO(2) effux from the thylakoid. More remains to be investigated about this CCM. The final topic is that of the occurrence of C(4)-like metabolism in the CCMs of marine diatoms. Different conclusions have been reached depending on the organism investigated and the techniques used, and several aspects require further study.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, College of Life Sciences, University of Dundee at SCRI, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK.
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119
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Goss R, Jakob T. Regulation and function of xanthophyll cycle-dependent photoprotection in algae. PHOTOSYNTHESIS RESEARCH 2010; 106:103-22. [PMID: 20224940 DOI: 10.1007/s11120-010-9536-x] [Citation(s) in RCA: 214] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 02/05/2010] [Indexed: 05/18/2023]
Abstract
The xanthophyll cycle represents one of the important photoprotection mechanisms in plant cells. In the present review, we summarize current knowledge about the violaxanthin cycle of vascular plants, green and brown algae, and the diadinoxanthin cycle of the algal classes Bacillariophyceae, Xanthophyceae, Haptophyceae, and Dinophyceae. We address the biochemistry of the xanthophyll cycle enzymes with a special focus on protein structure, co-substrate requirements and regulation of enzyme activity. We present recent ideas regarding the structural basis of xanthophyll cycle-dependent photoprotection, including different models for the mechanism of non-photochemical quenching of chlorophyll a fluorescence. In a dedicated chapter, we also describe the unique violaxanthin antheraxanthin cycle of the Prasinophyceae, together with its implication for the mechanism of xanthophyll cycle-dependent heat dissipation. The interaction between the diadinoxanthin cycle and alternative electron flow pathways in the chloroplasts of diatoms is an additional topic of this review, and in the last chapter we cover aspects of the importance of xanthophyll cycle-dependent photoprotection for different algal species in their natural environments.
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Affiliation(s)
- Reimund Goss
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany.
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120
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Finazzi G, Moreau H, Bowler C. Genomic insights into photosynthesis in eukaryotic phytoplankton. TRENDS IN PLANT SCIENCE 2010; 15:565-572. [PMID: 20800533 DOI: 10.1016/j.tplants.2010.07.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 07/21/2010] [Accepted: 07/22/2010] [Indexed: 05/29/2023]
Abstract
The evolution of photosynthesis completely altered the biogeochemistry of our planet and permitted the evolution of more complex multicellular organisms. Curiously, terrestrial photosynthesis is carried out largely by green algae and their descendents the higher plants, whereas in the ocean the most abundant photosynthetic eukaryotes are microscopic and have red algal affiliations. Although primary productivity is approximately equal between the land and the ocean, the marine microbes represent less than 1% of the photosynthetic biomass found on land. This review focuses on this highly successful and diverse group of organisms collectively known as phytoplankton and reviews how insights from whole genome analyses have improved our understanding of the novel innovations employed by them to maximize photosynthetic efficiency in variable light environments.
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Affiliation(s)
- Giovanni Finazzi
- Laboratoire de Physiologie Vegetale et Cellulaire, UMR 5168 Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Université Joseph Fourier, CEA Grenoble, 17 rue des Martyrs, 38054 Grenoble, France
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Szabó M, Premvardhan L, Lepetit B, Goss R, Wilhelm C, Garab G. Functional heterogeneity of the fucoxanthins and fucoxanthin-chlorophyll proteins in diatom cells revealed by their electrochromic response and fluorescence and linear dichroism spectra. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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122
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Gildenhoff N, Herz J, Gundermann K, Büchel C, Wachtveitl J. The excitation energy transfer in the trimeric fucoxanthin–chlorophyll protein from Cyclotella meneghiniana analyzed by polarized transient absorption spectroscopy. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.02.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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123
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Yamagishi A, Ikeda Y, Komura M, Koike H, Satoh K, Itoh S, Shibata Y. Shallow Sink in an Antenna Pigment System of Photosystem I of a Marine Centric Diatom, Chaetoceros gracilis, Revealed by Ultrafast Fluorescence Spectroscopy at 17 K. J Phys Chem B 2010; 114:9031-8. [DOI: 10.1021/jp102205v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atsushi Yamagishi
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yohei Ikeda
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Masayuki Komura
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Hiroyuki Koike
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Kazuhiko Satoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Shigeru Itoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yutaka Shibata
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, and Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
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Gildenhoff N, Amarie S, Gundermann K, Beer A, Büchel C, Wachtveitl J. Oligomerization and pigmentation dependent excitation energy transfer in fucoxanthin–chlorophyll proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:543-9. [DOI: 10.1016/j.bbabio.2010.01.024] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/21/2009] [Accepted: 01/19/2010] [Indexed: 11/28/2022]
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125
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Maberly SC, Courcelle C, Groben R, Gontero B. Phylogenetically-based variation in the regulation of the Calvin cycle enzymes, phosphoribulokinase and glyceraldehyde-3-phosphate dehydrogenase, in algae. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:735-45. [PMID: 19926682 DOI: 10.1093/jxb/erp337] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Aquatic photosynthesis is responsible for about half of the global production and is undertaken by a huge phylogenetic diversity of algae that are poorly studied. The diversity of redox-regulation of phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was investigated in a wide range of algal groups under standard conditions. Redox-regulation of PRK was greatest in chlorophytes, low or absent in a red alga and most chromalveolates, and linked to the number of amino acids between two regulatory cysteine residues. GAPDH regulation was not strongly-related to the different forms of this enzyme and was less variable than for PRK. Addition of recombinant CP12, a protein that forms a complex with PRK and GAPDH, to crude extracts inhibited GAPDH and PRK inversely in the Plantae, but in most chromalveolates had little effect on GAPDH and inhibited or stimulated PRK depending on the species. Patterns of enzyme regulation were used to produce a phylogenetic tree in which cryptophytes and haptophytes, at the base of the chromalveolates, formed a distinct clade. A second clade comprised only chromalveolates. A third clade comprised a mixture of Plantae, an excavate and three chromalveolates: a marine diatom and two others (a xanthophyte and eustigmatophyte) that are distinguished by a low content of chlorophyll c and a lack of fucoxanthin. Regulation of both enzymes was greater in freshwater than in marine taxa, possibly because most freshwaters are more dynamic than oceans. This work highlights the importance of understanding enzyme regulation in diverse algae if their ecology and productivity is to be understood.
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Affiliation(s)
- Stephen C Maberly
- Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
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126
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Park S, Jung G, Hwang YS, Jin E. Dynamic response of the transcriptome of a psychrophilic diatom, Chaetoceros neogracile, to high irradiance. PLANTA 2010; 231:349-360. [PMID: 19924439 DOI: 10.1007/s00425-009-1044-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 10/19/2009] [Indexed: 05/28/2023]
Abstract
Large-scale RNA profiling revealed that high irradiance differentially regulated 577 out of 1,439 non-redundant genes of the Antarctic marine diatom Chaetoceros neogracile, represented on a custom cDNA chip, during 6 h of treatment. Among genes that were up- or down-regulated more than twofold within 30 min of treatment (310/1,439), about half displayed an acclimatory response during 6 h under high light. Expression of the remaining non-acclimatory genes also rapidly returned to initial levels within 30 min following a shift to low irradiance. High light altered expression of most of the photosynthesis genes (48/70), in contrast to genes in other functional categories. In addition, opposite response patterns were provoked in genes encoding fucoxanthin chlorophyll a/c binding protein (FCP), the main component of the diatom light-harvesting complex; high irradiance caused a decrease in expression of most FCP genes, but drove the rapid and specific up-regulation of ten others. C. neogracile responded very promptly to a change in light intensity by rapidly adjusting the transcript levels of FCP genes up-regulated by high light, and these dynamic adjustments coincided well with diatoxanthin (Dtx) levels formed by the xanthophyll cycle under the same conditions. The observation that the non-photochemical quenching (NPQ) capacity of this polar diatom was highly dependent on Dtx, which could bind to FCP and trigger NPQ, suggests that the up-regulated FCP gene products may participate in a photoprotective process as Dtx-binding proteins.
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Affiliation(s)
- Seunghye Park
- Department of Life Science, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea
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127
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Goss R, Nerlich J, Lepetit B, Schaller S, Vieler A, Wilhelm C. The lipid dependence of diadinoxanthin de-epoxidation presents new evidence for a macrodomain organization of the diatom thylakoid membrane. JOURNAL OF PLANT PHYSIOLOGY 2009; 166:1839-54. [PMID: 19604599 DOI: 10.1016/j.jplph.2009.05.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 05/29/2009] [Indexed: 05/25/2023]
Abstract
The present study shows that thylakoid membranes of the diatom Cyclotella meneghiniana contain much higher amounts of negatively charged lipids than higher plant or green algal thylakoids. Based on these findings, we examined the influence of SQDG on the de-epoxidation reaction of the diadinoxanthin cycle and compared it with results from the second negatively charged thylakoid lipid PG. SQDG and PG exhibited a lower capacity for the solubilization of the hydrophobic xanthophyll cycle pigment diadinoxanthin than the main membrane lipid MGDG. Although complete pigment solubilization took place at higher concentrations of the negatively charged lipids, SQDG and PG strongly suppressed the de-epoxidation of diadinoxanthin in artificial membrane systems. In in vitro assays employing the isolated diadinoxanthin cycle enzyme diadinoxanthin de-epoxidase, no or only a very weak de-epoxidation reaction was observed in the presence of SQDG or PG, respectively. In binary mixtures of the inverted hexagonal phase forming lipid MGDG with the negatively charged bilayer lipids, comparable suppression took place. This is in contrast to binary mixtures of MGDG with the neutral bilayer lipids DGDG and PC, where rapid and efficient de-epoxidation was observed. In complex lipid mixtures resembling the lipid composition of the native diatom thylakoid membrane, we again found strong suppression of diadinoxanthin de-epoxidation due to the presence of SQDG or PG. We conclude that, in the native thylakoids of diatoms, a strict separation of the MGDG and SQDG domains must occur; otherwise, the rapid diadinoxanthin de-epoxidation observed in intact cells upon illumination would not be possible.
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Affiliation(s)
- Reimund Goss
- Institute of Biology I, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany.
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128
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Nymark M, Valle KC, Brembu T, Hancke K, Winge P, Andresen K, Johnsen G, Bones AM. An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum. PLoS One 2009; 4:e7743. [PMID: 19888450 PMCID: PMC2766053 DOI: 10.1371/journal.pone.0007743] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Accepted: 10/06/2009] [Indexed: 12/22/2022] Open
Abstract
Photosynthetic diatoms are exposed to rapid and unpredictable changes in irradiance and spectral quality, and must be able to acclimate their light harvesting systems to varying light conditions. Molecular mechanisms behind light acclimation in diatoms are largely unknown. We set out to investigate the mechanisms of high light acclimation in Phaeodactylum tricornutum using an integrated approach involving global transcriptional profiling, metabolite profiling and variable fluorescence technique. Algae cultures were acclimated to low light (LL), after which the cultures were transferred to high light (HL). Molecular, metabolic and physiological responses were studied at time points 0.5 h, 3 h, 6 h, 12 h, 24 h and 48 h after transfer to HL conditions. The integrated results indicate that the acclimation mechanisms in diatoms can be divided into an initial response phase (0–0.5 h), an intermediate acclimation phase (3–12 h) and a late acclimation phase (12–48 h). The initial phase is recognized by strong and rapid regulation of genes encoding proteins involved in photosynthesis, pigment metabolism and reactive oxygen species (ROS) scavenging systems. A significant increase in light protecting metabolites occur together with the induction of transcriptional processes involved in protection of cellular structures at this early phase. During the following phases, the metabolite profiling display a pronounced decrease in light harvesting pigments, whereas the variable fluorescence measurements show that the photosynthetic capacity increases strongly during the late acclimation phase. We show that P. tricornutum is capable of swift and efficient execution of photoprotective mechanisms, followed by changes in the composition of the photosynthetic machinery that enable the diatoms to utilize the excess energy available in HL. Central molecular players in light protection and acclimation to high irradiance have been identified.
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Affiliation(s)
- Marianne Nymark
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kristin C. Valle
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tore Brembu
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kasper Hancke
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Per Winge
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kjersti Andresen
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Geir Johnsen
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Atle M. Bones
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
- * E-mail:
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Antal TK, Matorin DN, Ilyash LV, Volgusheva AA, Osipov V, Konyuhov IV, Krendeleva TE, Rubin AB. Probing of photosynthetic reactions in four phytoplanktonic algae with a PEA fluorometer. PHOTOSYNTHESIS RESEARCH 2009; 102:67-76. [PMID: 19731073 DOI: 10.1007/s11120-009-9491-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2009] [Accepted: 08/17/2009] [Indexed: 05/24/2023]
Abstract
High-resolution light-induced kinetics of chlorophyll fluorescence (OJIP transients) were recorded and analyzed in cultures of diatoms (Thalassiosira weissflogii, Chaetoceros mulleri) and dinoflagellates (Amphidinium carterae, Prorocentrum minimum). Fluorescence transients showed the rapid exponential initial rise from the point O indicating low connectivity between PS II units and high absorption cross-section of PS II antenna. Dark-adapted dinoflagellates revealed capability to maintain the PS I-mediated re-oxidation of the PQ pool at the exposure to strong actinic light that may lead to the underestimation of F(M) value. In OJIP transients recorded in phytoplanktonic algae the fluorescence yield at the point O exceeded F(O) level because Q(A) has been already partly reduced at 50 micros after the illumination onset. PEA was also employed to study the recovery of photosynthetic reactions in T. weissflogii during incubation of nitrogen starved cells in N-replete medium. N limitation caused the impairment of electron transport between Q(A) and PQs, accumulation of closed PS II centers, and the reduced ability to generate transmembrane DeltapH upon illumination, almost fully restored during the recovery period. The recovered cells showed much higher values of NPQ than control ones suggesting maximization of photoprotection mechanisms in the population with a 'stress history.'
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Affiliation(s)
- T K Antal
- Faculty of Biology, Moscow State University, Moscow, Russia.
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130
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Granum E, Roberts K, Raven JA, Leegood RC. PRIMARY CARBON AND NITROGEN METABOLIC GENE EXPRESSION IN THE DIATOM THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE): DIEL PERIODICITY AND EFFECTS OF INORGANIC CARBON AND NITROGEN(1). JOURNAL OF PHYCOLOGY 2009; 45:1083-92. [PMID: 27032353 DOI: 10.1111/j.1529-8817.2009.00728.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Diel periodicity and effects of inorganic carbon (Ci ) and NO3 (-) on the expression of 11 key genes for primary carbon and nitrogen metabolism, including potential C4 photosynthesis, in the marine diatom Thalassiosira pseudonana Hasle et Heimdal were investigated. Target gene transcripts were measured by quantitative reverse transcriptase-PCR, and some of the gene-encoded proteins were analyzed by Western blotting. The diatom was grown with a 12 h photoperiod at two different Ci concentrations maintained by air-equilibration with either 380 μL · L(-1) (near-ambient) or 100 μL · L(-1) (low) CO2 . Transcripts of the principal Ci and NO3 (-) assimilatory genes RUBISCO LSU (rbcL) and nitrate reductase displayed very strong diel oscillations with peaks at the end of the scotophase. Considerable diel periodicities were also exhibited by the β-carboxylase genes phosphoenolpyruvate carboxylase (PEPC1 and PEPC2) and phosphoenolpyruvate carboxykinase (PEPCK), and the Benson-Calvin cycle gene sedoheptulose-bisphosphatase (SBPase), with peaks during mid- to late scotophase. In accordance with the transcripts, there were substantial diel periodicities in PEPC1, PEPC2, PEPCK, and especially rbcL proteins, although they peaked during early to mid-photophase. Inorganic carbon had some transient effects on the β-carboxylase transcripts, and glycine decarboxylase P subunit was highly up-regulated by low Ci concentration, indicating increased capacity for photorespiration. Nitrogen-starved cells had reduced amounts of carbon metabolic gene transcripts, but the PEPC1, PEPC2, PEPCK, and rbcL transcripts increased rapidly when NO3 (-) was replenished. The results suggest that the β-carboxylases in T. pseudonana play key anaplerotic roles but show no clear support for C4 photosynthesis.
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Affiliation(s)
- Espen Granum
- Robert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UKDivision of Plant Sciences, University of Dundee at Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UKRobert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Karen Roberts
- Robert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UKDivision of Plant Sciences, University of Dundee at Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UKRobert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - John A Raven
- Robert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UKDivision of Plant Sciences, University of Dundee at Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UKRobert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Richard C Leegood
- Robert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UKDivision of Plant Sciences, University of Dundee at Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UKRobert Hill Institute and Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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Maruyama S, Matsuzaki M, Misawa K, Nozaki H. Cyanobacterial contribution to the genomes of the plastid-lacking protists. BMC Evol Biol 2009; 9:197. [PMID: 19664294 PMCID: PMC3087521 DOI: 10.1186/1471-2148-9-197] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 08/11/2009] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Eukaryotic genes with cyanobacterial ancestry in plastid-lacking protists have been regarded as important evolutionary markers implicating the presence of plastids in the early evolution of eukaryotes. Although recent genomic surveys demonstrated the presence of cyanobacterial and algal ancestry genes in the genomes of plastid-lacking protists, comparative analyses on the origin and distribution of those genes are still limited. RESULTS We identified 12 gene families with cyanobacterial ancestry in the genomes of a taxonomically wide range of plastid-lacking eukaryotes (Phytophthora [Chromalveolata], Naegleria [Excavata], Dictyostelium [Amoebozoa], Saccharomyces and Monosiga [Opisthokonta]) using a novel phylogenetic pipeline. The eukaryotic gene clades with cyanobacterial ancestry were mostly composed of genes from bikonts (Archaeplastida, Chromalveolata, Rhizaria and Excavata). We failed to find genes with cyanobacterial ancestry in Saccharomyces and Dictyostelium, except for a photorespiratory enzyme conserved among fungi. Meanwhile, we found several Monosiga genes with cyanobacterial ancestry, which were unrelated to other Opisthokonta genes. CONCLUSION Our data demonstrate that a considerable number of genes with cyanobacterial ancestry have contributed to the genome composition of the plastid-lacking protists, especially bikonts. The origins of those genes might be due to lateral gene transfer events, or an ancient primary or secondary endosymbiosis before the diversification of bikonts. Our data also show that all genes identified in this study constitute multi-gene families with punctate distribution among eukaryotes, suggesting that the transferred genes could have survived through rounds of gene family expansion and differential reduction.
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Affiliation(s)
- Shinichiro Maruyama
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - Motomichi Matsuzaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
- Current address: Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
- Current address: Research Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Kazuharu Misawa
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
- Current address: Research Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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132
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Materna AC, Sturm S, Kroth PG, Lavaud J. FIRST INDUCED PLASTID GENOME MUTATIONS IN AN ALGA WITH SECONDARY PLASTIDS: psbA MUTATIONS IN THE DIATOM PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE) REVEAL CONSEQUENCES ON THE REGULATION OF PHOTOSYNTHESIS(1). JOURNAL OF PHYCOLOGY 2009; 45:838-46. [PMID: 27034213 DOI: 10.1111/j.1529-8817.2009.00711.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Diatoms play a crucial role in the biochemistry and ecology of most aquatic ecosystems, especially because of their high photosynthetic productivity. They often have to cope with a fluctuating light climate and a punctuated exposure to excess light, which can be harmful for photosynthesis. To gain insight into the regulation of photosynthesis in diatoms, we generated and studied mutants of the diatom Phaeodactylum tricornutum Bohlin carrying functionally altered versions of the plastidic psbA gene encoding the D1 protein of the PSII reaction center (PSII RC). All analyzed mutants feature an amino acid substitution in the vicinity of the QB -binding pocket of D1. We characterized the photosynthetic capacity of the mutants in comparison to wildtype cells, focusing on the way they regulate their photochemistry as a function of light intensity. The results show that the mutations resulted in constitutive changes of PSII electron transport rates. The extent of the impairment varies between mutants depending on the proximity of the mutation to the QB -binding pocket and/or to the nonheme iron within the PSII RC. The effects of the mutations described here for P. tricornutum are similar to effects in cyanobacteria and green microalgae, emphasizing the conservation of the D1 protein structure among photosynthetic organisms of different evolutionary origins.
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Affiliation(s)
- Arne C Materna
- Group of Plant Ecophysiology, Biology Department, Mailbox M611, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Sabine Sturm
- Group of Plant Ecophysiology, Biology Department, Mailbox M611, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Peter G Kroth
- Group of Plant Ecophysiology, Biology Department, Mailbox M611, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Johann Lavaud
- Group of Plant Ecophysiology, Biology Department, Mailbox M611, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
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133
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Identification of a specific fucoxanthin-chlorophyll protein in the light harvesting complex of photosystem I in the diatom Cyclotella meneghiniana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:905-12. [DOI: 10.1016/j.bbabio.2009.04.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 03/30/2009] [Accepted: 04/20/2009] [Indexed: 11/17/2022]
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134
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Ramachandra TV, Mahapatra DM, B K, Gordon R. Milking Diatoms for Sustainable Energy: Biochemical Engineering versus Gasoline-Secreting Diatom Solar Panels. Ind Eng Chem Res 2009. [DOI: 10.1021/ie900044j] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- T. V. Ramachandra
- Energy & Wetlands Research Group, Centre for Ecological Sciences/Centre for Sustainable Technologies, Indian Institute of Science, Bangalore 560 012, India
| | - Durga Madhab Mahapatra
- Energy & Wetlands Research Group, Centre for Ecological Sciences/Centre for Sustainable Technologies, Indian Institute of Science, Bangalore 560 012, India
| | - Karthick B
- Energy & Wetlands Research Group, Centre for Ecological Sciences/Centre for Sustainable Technologies, Indian Institute of Science, Bangalore 560 012, India
| | - Richard Gordon
- Department of Radiology, University of Manitoba, Room GA216, HSC, 820 Sherbrook Street, Winnipeg MB R3A 1R9, Canada
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135
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Weber T, Gruber A, Kroth PG. The presence and localization of thioredoxins in diatoms, unicellular algae of secondary endosymbiotic origin. MOLECULAR PLANT 2009; 2:468-77. [PMID: 19825630 DOI: 10.1093/mp/ssp010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Diatoms are unicellular algae of great ecological importance. So far, very little is known about the regulation of carbon fixation in these algae; however, there are strong indications that in diatom plastids, the ferredoxin/thioredoxin system might play a minor role in redox regulation of the photosynthetic reactions compared to land plants. Until now, it is unknown whether there are fewer or other target enzymes of thioredoxins in diatoms. Only a single potential target enzyme for thioredoxin, the plastidic fructose-1,6-bisphosphatase, has yet been identified. Nevertheless, during the annotation of the genome of the diatom Phaeodactylum tricornutum, we identified several genes encoding different thioredoxins. Utilizing in vivo expression of GFP:presequence fusion proteins in P. tricornutum, we were able to show that these thioredoxins are targeted either into plastids, mitochondria, or remain in the cytosol. Surprisingly, two of the three usually cytosolic thioredoxin h proteins are apparently plastid associated and, together with a thioredoxin reductase, putatively located in the periplastidic compartment. This is one of the few indications for so far unknown enzymatic reactions in the space between the two pairs of diatom plastid envelope membranes.
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Affiliation(s)
- Till Weber
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
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136
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Gruber A, Weber T, Bártulos CR, Vugrinec S, Kroth PG. Intracellular distribution of the reductive and oxidative pentose phosphate pathways in two diatoms. J Basic Microbiol 2009; 49:58-72. [PMID: 19206144 DOI: 10.1002/jobm.200800339] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Diatoms contribute a large proportion to the worldwide primary production and are particularly effective in fixing carbon dioxide. Possibly because diatom plastids originate from a secondary endocytobiosis, their cellular structure is more complex and metabolic pathways are rearranged within diatom cells compared to cells containing primary plastids. We annotated genes encoding isozymes of the reductive and oxidative pentose phosphate pathways in the genomes of the centric diatom Thalassiosira pseudonana and the pennate diatom Phaeodactylum tricornutum and bioinformatically inferred their intracellular distribution. Prediction results were confirmed by fusion of selected presequences to Green Fluorescent Protein and expression of these constructs in P. tricornutum. Calvin cycle enzymes for the carbon fixation and reduction of 3-phosphoglycerate are present in single isoforms, while we found multiple isoenzymes involved in the regeneration of ribulose-1,5-bisphosphate. We only identified one cytosolic sedoheptulose-1,7-bisphosphatase in both investigated diatoms. The oxidative pentose phosphate pathway seems to be restricted to the cytosol in diatoms, since we did not find stromal glucose-6-phosphate dehydrogenase and 6-phosphogluconolactone dehydrogenase isoforms. However, the two species apparently possess a plastidic phosphogluconolactonase. A 6-phosphogluconolactone dehydrogenase is apparently plastid associated in P. tricornutum and might be active in the periplastidic compartment, suggesting that this compartment might be involved in metabolic processes in diatoms.
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Affiliation(s)
- Ansgar Gruber
- Pflanzliche Okophysiologie, Universität Konstanz, Konstanz, Germany.
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137
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138
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van de Poll WH, Buma AGJ. Does ultraviolet radiation affect the xanthophyll cycle in marine phytoplankton? Photochem Photobiol Sci 2009; 8:1295-301. [DOI: 10.1039/b904501e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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139
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Erales J, Gontero B, Maberly SC. SPECIFICITY AND FUNCTION OF GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE IN A FRESHWATER DIATOM, ASTERIONELLA FORMOSA (BACILLARIOPHYCEAE)(1). JOURNAL OF PHYCOLOGY 2008; 44:1455-1464. [PMID: 27039860 DOI: 10.1111/j.1529-8817.2008.00600.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The plastidic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the only reductive step in the Calvin cycle and exists as different forms of which GapC1 enzyme is present in chromalveolates, such as diatoms. Biochemical studies on diatoms are still fragmentary, and, thus, in this report, GAPDH from the freshwater diatom Asterionella formosa Hassall has been purified and kinetically characterized. It is a homotetrameric enzyme with a molecular mass of ~150 ± 15 kDa. The enzyme showed Michaelis-Menten kinetics with respect to both cofactors, NADPH and NADH, with a 16-fold greater catalytic constant for NADPH. The Km for NADPH was 140 μM, the lowest affinity reported, while the catalytic constant, 815 s(-1) , is the highest reported. The Km for NADH was 93 μM, and the catalytic constant was 50 s(-1) , both are similar to reported values for other types of GAPDH. The GapC1 enzyme, like the Chlamydomonas reinhardtii A4 GAPDH, exhibits a cooperative behavior toward the substrate, 1,3-bisphosphoglyceric acid (BPGA), with both cofactors. Mass spectrometry analysis showed that when GapC1 enzyme was purified without reducing agents, it copurified with a small protein with a mass of 8.2 kDa. This protein was recognized by antibodies against CP12. When associated with this protein, GAPDH displayed a lag that disappeared upon incubation with reducing agent in the presence of either BPGA or NADPH as a consequence of dissociation of the GAPDH/CP12 complex. Thus, as in other species of algae and higher plants, regulation of GapC1 enzyme in A. formosa may occur through association-dissociation processes linked to dark-light transitions.
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Affiliation(s)
- Jenny Erales
- Laboratoire de Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13 402 Marseille Cedex 20 FranceCentre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | - Brigitte Gontero
- Laboratoire de Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13 402 Marseille Cedex 20 FranceCentre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | - Stephen C Maberly
- Laboratoire de Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13 402 Marseille Cedex 20 FranceCentre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
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140
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Gillard J, Devos V, Huysman MJJ, De Veylder L, D'Hondt S, Martens C, Vanormelingen P, Vannerum K, Sabbe K, Chepurnov VA, Inzé D, Vuylsteke M, Vyverman W. Physiological and transcriptomic evidence for a close coupling between chloroplast ontogeny and cell cycle progression in the pennate diatom Seminavis robusta. PLANT PHYSIOLOGY 2008; 148:1394-411. [PMID: 18820084 PMCID: PMC2577256 DOI: 10.1104/pp.108.122176] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 09/18/2008] [Indexed: 05/18/2023]
Abstract
Despite the growing interest in diatom genomics, detailed time series of gene expression in relation to key cellular processes are still lacking. Here, we investigated the relationships between the cell cycle and chloroplast development in the pennate diatom Seminavis robusta. This diatom possesses two chloroplasts with a well-orchestrated developmental cycle, common to many pennate diatoms. By assessing the effects of induced cell cycle arrest with microscopy and flow cytometry, we found that division and reorganization of the chloroplasts are initiated only after S-phase progression. Next, we quantified the expression of the S. robusta FtsZ homolog to address the division status of chloroplasts during synchronized growth and monitored microscopically their dynamics in relation to nuclear division and silicon deposition. We show that chloroplasts divide and relocate during the S/G2 phase, after which a girdle band is deposited to accommodate cell growth. Synchronized cultures of two genotypes were subsequently used for a cDNA-amplified fragment length polymorphism-based genome-wide transcript profiling, in which 917 reproducibly modulated transcripts were identified. We observed that genes involved in pigment biosynthesis and coding for light-harvesting proteins were up-regulated during G2/M phase and cell separation. Light and cell cycle progression were both found to affect fucoxanthin-chlorophyll a/c-binding protein expression and accumulation of fucoxanthin cell content. Because chloroplasts elongate at the stage of cytokinesis, cell cycle-modulated photosynthetic gene expression and synthesis of pigments in concert with cell division might balance chloroplast growth, which confirms that chloroplast biogenesis in S. robusta is tightly regulated.
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Affiliation(s)
- Jeroen Gillard
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, B-9000 Gent, Belgium.
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141
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Evolutionary origins and functions of the carotenoid biosynthetic pathway in marine diatoms. PLoS One 2008; 3:e2896. [PMID: 18682837 PMCID: PMC2483416 DOI: 10.1371/journal.pone.0002896] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Accepted: 07/07/2008] [Indexed: 01/09/2023] Open
Abstract
Carotenoids are produced by all photosynthetic organisms, where they play essential roles in light harvesting and photoprotection. The carotenoid biosynthetic pathway of diatoms is largely unstudied, but is of particular interest because these organisms have a very different evolutionary history with respect to the Plantae and are thought to be derived from an ancient secondary endosymbiosis between heterotrophic and autotrophic eukaryotes. Furthermore, diatoms have an additional xanthophyll-based cycle for dissipating excess light energy with respect to green algae and higher plants. To explore the origins and functions of the carotenoid pathway in diatoms we searched for genes encoding pathway components in the recently completed genome sequences of two marine diatoms. Consistent with the supplemental xanthophyll cycle in diatoms, we found more copies of the genes encoding violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP) enzymes compared with other photosynthetic eukaryotes. However, the similarity of these enzymes with those of higher plants indicates that they had very probably diversified before the secondary endosymbiosis had occurred, implying that VDE and ZEP represent early eukaryotic innovations in the Plantae. Consequently, the diatom chromist lineage likely obtained all paralogues of ZEP and VDE genes during the process of secondary endosymbiosis by gene transfer from the nucleus of the algal endosymbiont to the host nucleus. Furthermore, the presence of a ZEP gene in Tetrahymena thermophila provides the first evidence for a secondary plastid gene encoded in a heterotrophic ciliate, providing support for the chromalveolate hypothesis. Protein domain structures and expression analyses in the pennate diatom Phaeodactylum tricornutum indicate diverse roles for the different ZEP and VDE isoforms and demonstrate that they are differentially regulated by light. These studies therefore reveal the ancient origins of several components of the carotenoid biosynthesis pathway in photosynthetic eukaryotes and provide information about how they have diversified and acquired new functions in the diatoms.
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142
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Becker B, Hoef-Emden K, Melkonian M. Chlamydial genes shed light on the evolution of photoautotrophic eukaryotes. BMC Evol Biol 2008; 8:203. [PMID: 18627593 PMCID: PMC2490706 DOI: 10.1186/1471-2148-8-203] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 07/15/2008] [Indexed: 11/10/2022] Open
Abstract
Background Chlamydiae are obligate intracellular bacteria of protists, invertebrates and vertebrates, but have not been found to date in photosynthetic eukaryotes (algae and embryophytes). Genes of putative chlamydial origin, however, are present in significant numbers in sequenced genomes of photosynthetic eukaryotes. It has been suggested that such genes were acquired by an ancient horizontal gene transfer from Chlamydiae to the ancestor of photosynthetic eukaryotes. To further test this hypothesis, an extensive search for proteins of chlamydial origin was performed using several recently sequenced algal genomes and EST databases, and the proteins subjected to phylogenetic analyses. Results A total of 39 proteins of chlamydial origin were retrieved from the photosynthetic eukaryotes analyzed and their identity verified through phylogenetic analyses. The distribution of the chlamydial proteins among four groups of photosynthetic eukaryotes (Viridiplantae, Rhodoplantae, Glaucoplantae, Bacillariophyta) was complex suggesting multiple acquisitions and losses. Evidence is presented that all except one of the chlamydial genes originated from an ancient endosymbiosis of a chlamydial bacterium into the ancestor of the Plantae before their divergence into Viridiplantae, Rhodoplantae and Glaucoplantae, i.e. more than 1.1 BYA. The chlamydial proteins subsequently spread through secondary plastid endosymbioses to other eukaryotes. Of 20 chlamydial proteins recovered from the genomes of two Bacillariophyta, 10 were of rhodoplant, and 10 of viridiplant origin suggesting that they were acquired by two different secondary endosymbioses. Phylogenetic analyses of concatenated sequences demonstrated that the viridiplant secondary endosymbiosis likely occurred before the divergence of Chlorophyta and Streptophyta. Conclusion We identified 39 proteins of chlamydial origin in photosynthetic eukaryotes signaling an ancient invasion of the ancestor of the Plantae by a chlamydial bacterium accompanied by horizontal gene transfer. Subsequently, chlamydial proteins spread through secondary endosymbioses to other eukaryotes. We conclude that intracellular chlamydiae likely persisted throughout the early history of the Plantae donating genes to their hosts that replaced their cyanobacterial/plastid homologs thus shaping early algal/plant evolution before they eventually vanished.
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Affiliation(s)
- Burkhard Becker
- Botanisches Institut, Universität zu Köln, Gyrhofstr. 15, 50931 Köln, Germany.
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143
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Szabó M, Lepetit B, Goss R, Wilhelm C, Mustárdy L, Garab G. Structurally flexible macro-organization of the pigment-protein complexes of the diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2008; 95:237-45. [PMID: 17891473 DOI: 10.1007/s11120-007-9252-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 09/07/2007] [Indexed: 05/17/2023]
Abstract
By means of circular dichroism (CD) spectroscopy, we have characterized the organization of the photosynthetic complexes of the diatom Phaeodactylum tricornutum at different levels of structural complexity: in intact cells, isolated thylakoid membranes and purified fucoxanthin chlorophyll protein (FCP) complexes. We found that the CD spectrum of whole cells was dominated by a large band at (+)698 nm, accompanied by a long tail from differential scattering, features typical for psi-type (polymerization or salt-induced) CD. The CD spectrum additionally contained intense (-)679 nm, (+)445 nm and (-)470 nm bands, which were also present in isolated thylakoid membranes and FCPs. While the latter two bands were evidently produced by excitonic interactions, the nature of the (-)679 nm band remained unclear. Electrochromic absorbance changes also revealed the existence of a CD-silent long-wavelength ( approximately 545 nm) absorbing fucoxanthin molecule with very high sensitivity to the transmembrane electrical field. In intact cells the main CD band at (+)698 nm appeared to be associated with the multilamellar organization of the thylakoid membranes. It was sensitive to the osmotic pressure and was selectively diminished at elevated temperatures and was capable of undergoing light-induced reversible changes. In isolated thylakoid membranes, the psi-type CD band, which was lost during the isolation procedure, could be partially restored by addition of Mg-ions, along with the maximum quantum yield and the non-photochemical quenching of singlet excited chlorophyll a, measured by fluorescence transients.
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Affiliation(s)
- Milán Szabó
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, PO Box 521, 6701, Szeged, Hungary
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144
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Gundermann K, Büchel C. The fluorescence yield of the trimeric fucoxanthin-chlorophyll-protein FCPa in the diatom Cyclotella meneghiniana is dependent on the amount of bound diatoxanthin. PHOTOSYNTHESIS RESEARCH 2008; 95:229-35. [PMID: 17912602 DOI: 10.1007/s11120-007-9262-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 09/10/2007] [Indexed: 05/12/2023]
Abstract
The fluorescence yield of isolated fucoxanthin chlorophyll proteins, serving as light harvesting proteins in diatoms, was compared to the amount of diatoxanthin bound. Diatoxanthin was earlier shown to be involved in the xanthophyll cycle in diatoms as a functional analogue of zeaxanthin in higher plants. By growing cells under different light conditions, the amount of diatoxanthin in both the trimeric FCPa as well as the oligomeric FCPb of the diatom Cyclotella meneghiniana was increased. In the trimeric FCPa, the fluorescence yield decreased with increasing diatoxanthin content, whereas in the oligomeric FCPb fluorescence was generally lower, albeit constant. No pH dependence of fluorescence yield could be demonstrated except for artificially aggregated FCPa. Thus, diatoxanthin is able to quench fluorescence in FCPa, but the yield is also influenced by pH when the protein becomes aggregated.
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Affiliation(s)
- Kathi Gundermann
- Institute of Molecular Biosciences, University of Frankfurt, Siesmayerstr. 70, Frankfurt, 60323, Germany.
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145
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Kroth PG, Chiovitti A, Gruber A, Martin-Jezequel V, Mock T, Parker MS, Stanley MS, Kaplan A, Caron L, Weber T, Maheswari U, Armbrust EV, Bowler C. A model for carbohydrate metabolism in the diatom Phaeodactylum tricornutum deduced from comparative whole genome analysis. PLoS One 2008; 3:e1426. [PMID: 18183306 PMCID: PMC2173943 DOI: 10.1371/journal.pone.0001426] [Citation(s) in RCA: 281] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Accepted: 12/11/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Diatoms are unicellular algae responsible for approximately 20% of global carbon fixation. Their evolution by secondary endocytobiosis resulted in a complex cellular structure and metabolism compared to algae with primary plastids. METHODOLOGY/PRINCIPAL FINDINGS The whole genome sequence of the diatom Phaeodactylum tricornutum has recently been completed. We identified and annotated genes for enzymes involved in carbohydrate pathways based on extensive EST support and comparison to the whole genome sequence of a second diatom, Thalassiosira pseudonana. Protein localization to mitochondria was predicted based on identified similarities to mitochondrial localization motifs in other eukaryotes, whereas protein localization to plastids was based on the presence of signal peptide motifs in combination with plastid localization motifs previously shown to be required in diatoms. We identified genes potentially involved in a C4-like photosynthesis in P. tricornutum and, on the basis of sequence-based putative localization of relevant proteins, discuss possible differences in carbon concentrating mechanisms and CO(2) fixation between the two diatoms. We also identified genes encoding enzymes involved in photorespiration with one interesting exception: glycerate kinase was not found in either P. tricornutum or T. pseudonana. Various Calvin cycle enzymes were found in up to five different isoforms, distributed between plastids, mitochondria and the cytosol. Diatoms store energy either as lipids or as chrysolaminaran (a beta-1,3-glucan) outside of the plastids. We identified various beta-glucanases and large membrane-bound glucan synthases. Interestingly most of the glucanases appear to contain C-terminal anchor domains that may attach the enzymes to membranes. CONCLUSIONS/SIGNIFICANCE Here we present a detailed synthesis of carbohydrate metabolism in diatoms based on the genome sequences of Thalassiosira pseudonana and Phaeodactylum tricornutum. This model provides novel insights into acquisition of dissolved inorganic carbon and primary metabolic pathways of carbon in two different diatoms, which is of significance for an improved understanding of global carbon cycles.
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Affiliation(s)
- Peter G Kroth
- Fachbereich Biologie, University of Konstanz, Konstanz, Germany.
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146
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Vieler A, Wilhelm C, Goss R, Süss R, Schiller J. The lipid composition of the unicellular green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana investigated by MALDI-TOF MS and TLC. Chem Phys Lipids 2007; 150:143-55. [PMID: 17681288 DOI: 10.1016/j.chemphyslip.2007.06.224] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 06/26/2007] [Accepted: 06/28/2007] [Indexed: 11/22/2022]
Abstract
The lipid composition of algae is crucial for numerous structural and physiological aspects, e.g. the integrity of the photosynthetic complexes and the functionality of membrane-embedded processes as the photosynthetic electron transport in thylakoids or the mitochondrial respiration. In this paper the lipid composition of the organic extracts of the green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana are compared by using matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) in combination with thin-layer chromatography (TLC). The combined methods enable quantitative evaluation of the individual lipid classes as well as the determination of the relative acyl compositions. It will be shown that both algae differ in (a) the lipid classes, (b) the relative contribution of the individual lipid classes and (c) the acyl compositions. Differences in the acyl composition concern particularly the mono- and digalactosyl diacylglycerols. Glycerol-trimethylhomoserine and phosphatidylethanolamine are exclusively detected in the C. reinhardtii extracts, whereas phosphatidylcholine is a characteristic lipid of C. meneghiniana. Furthermore, the proportion of the acidic lipids sulfoquinovosyl-diacylglycerol and phosphatidylglycerol is significantly higher in the diatom than in C. reinhardtii.
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Affiliation(s)
- Astrid Vieler
- University of Leipzig, Faculty of Biosciences, Pharmacy and Psychology, Institute of Biology I, Johannisallee 21-23, D-04103 Leipzig, Germany
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147
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Veith T, Büchel C. The monomeric photosystem I-complex of the diatom Phaeodactylum tricornutum binds specific fucoxanthin chlorophyll proteins (FCPs) as light-harvesting complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1428-35. [PMID: 18028870 DOI: 10.1016/j.bbabio.2007.09.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 09/11/2007] [Accepted: 09/17/2007] [Indexed: 11/18/2022]
Abstract
A photosystem I (PSI)-fucoxanthin chlorophyll protein (FCP) complex with a chlorophyll a/P700 ratio of approximately 200:1 was isolated from the diatom Phaeodactylum tricornutum. Spectroscopic analysis proved that the more tightly bound FCP functions as a light-harvesting complex, actively transferring light energy from its accessory pigments chlorophyll c and fucoxanthin to the PSI core. Using an antibody against all FCP polypeptides of Cyclotella cryptica it could be shown that the polypeptides of the major FCP fraction differ from the FCPs found in the PSI fraction. Since these FCPs are tightly bound to PSI, active in energy transfer, and not found in the main FCP fraction, we suppose them to be PSI specific. Blue Native-PAGE, gel filtration and first electron microscopy studies of the PSI-FCP sample revealed a monomeric complex comparable in size and shape to the PSI-LHCI complex of green algae.
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Affiliation(s)
- Thomas Veith
- Institute of Molecular Biosciences, Johann Wolfgang Goethe-University, Siesmayerstrasse 70, D-60323 Frankfurt am Main, Germany
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148
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Roberts K, Granum E, Leegood RC, Raven JA. C3 and C4 pathways of photosynthetic carbon assimilation in marine diatoms are under genetic, not environmental, control. PLANT PHYSIOLOGY 2007; 145:230-5. [PMID: 17644625 PMCID: PMC1976569 DOI: 10.1104/pp.107.102616] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 07/09/2007] [Indexed: 05/03/2023]
Abstract
Marine diatoms are responsible for up to 20% of global CO(2) fixation. Their photosynthetic efficiency is enhanced by concentrating CO(2) around Rubisco, diminishing photorespiration, but the mechanism is yet to be resolved. Diatoms have been regarded as C(3) photosynthesizers, but recent metabolic labeling and genome sequencing data suggest that they perform C(4) photosynthesis. We studied the pathways of photosynthetic carbon assimilation in two diatoms by short-term metabolic (14)C labeling. In Thalassiosira weissflogii, both C3 (glycerate-P and triose-P) and C4 (mainly malate) compounds were major initial (2-5 s) products, whereas Thalassiosira pseudonana produced mainly C3 and C6 (hexose-P) compounds. The data provide evidence of C(3)-C(4) intermediate photosynthesis in T. weissflogii, but exclusively C(3) photosynthesis in T. pseudonana. The labeling patterns were the same for cells grown at near-ambient (380 microL L(-1)) and low (100 microL L(-1)) CO(2) concentrations. The lack of environmental modulation of carbon assimilatory pathways was supported in T. pseudonana by measurements of gene transcript and protein abundances of C(4)-metabolic enzymes (phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase) and Rubisco. This study suggests that the photosynthetic pathways of diatoms are diverse, and may involve combined CO(2)-concentrating mechanisms. Furthermore, it emphasizes the requirement for metabolic and functional genetic and enzymic analyses before accepting the presence of C(4)-metabolic enzymes as evidence for C(4) photosynthesis.
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Affiliation(s)
- Karen Roberts
- Plant Research Unit, University of Dundee at Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom
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149
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Ribalet F, Wichard T, Pohnert G, Ianora A, Miralto A, Casotti R. Age and nutrient limitation enhance polyunsaturated aldehyde production in marine diatoms. PHYTOCHEMISTRY 2007; 68:2059-67. [PMID: 17575990 DOI: 10.1016/j.phytochem.2007.05.012] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 05/08/2007] [Accepted: 05/08/2007] [Indexed: 05/15/2023]
Abstract
Skeletonema marinoi produces 2,4-heptadienal, 2,4-octadienal, and 2,4,7-octatrienal, the latter only in traces. In nutrient-replete cultures, the production of potentially defensive polyunsaturated aldehydes (PUA) increases from the exponential to the stationary phase of growth from 1.2 fmol cell(-1) (+/-0.4 fmol cell(-1) SD) to 4.2 fmol cell(-1) (+/-1.0 fmol cell(-1) SD), with 2,4-heptadienal as the dominant aldehyde. The plasticity of PUA production with age of the culture supports the hypothesis of a direct link between toxin production and cell physiological state. N- and P-limited cells in stationary phase produced 1.4 and 1.8 fold higher amounts of PUA than control cultures and 10.7 and 4.6 times higher PUAs when compared to their own exponential growth phase, respectively. The increase in PUA production in the nutrient-limited cultures was not paralleled by an increase in the total amount of precursor fatty acids indicating that physiological stress might trigger an enhanced expression or activity of the enzymes responsible for PUA production, i.e. chemical defense increase in aged and nutrient-stressed diatoms. If this holds true during blooms, grazers feeding at the end of a bloom would be more affected than early-bloom grazers.
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Affiliation(s)
- François Ribalet
- Stazione Zoologica Anton Dohrn di Napoli, Villa Comunale, I80121 Napoli, Italy
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150
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Beer A, Gundermann K, Beckmann J, Büchel C. Subunit Composition and Pigmentation of Fucoxanthin−Chlorophyll Proteins in Diatoms: Evidence for a Subunit Involved in Diadinoxanthin and Diatoxanthin Binding†. Biochemistry 2006; 45:13046-53. [PMID: 17059221 DOI: 10.1021/bi061249h] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two different fucoxanthin-chlorophyll protein complexes (FCP) were purified from the centric diatom Cyclotella meneghiniana and characterized with regard to their polypeptide and pigment composition. Whereas the oligomeric FCPb complex is most probably composed of fcp5 gene products, the trimeric FCPa has subunits encoded by fcp1-3 and fcp6/7. The amount of the latter polypeptide is enhanced when FCPa is isolated from algae grown under HL conditions. This increase in Fcp6/7 polypeptides is accompanied by an increase in the pool of xanthophyll cycle pigments, diadinoxanthin and diatoxanthin, and a concomitant decrease in fucoxanthin content. In addition, the de-epoxidation ratio, i.e., the amount of diatoxanthin in relation to the pool of xanthophyll cycle pigments, is increased by a factor of 2. With regard to fluorescence yield, HL FCPa was quenched in comparison to LL FCPa. This is in accordance with the larger amount of diatoxanthin that is bound, which is supposed to act as a quencher like zeaxanthin in higher plants. Thus, we conclude that the enhanced content of diatoxanthin in FCPa plays a protective role, which is paralleled by a weakened light harvesting function due to a smaller amount of fucoxanthin.
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Affiliation(s)
- Anja Beer
- Institute of Molecular Biosciences, Department of Biosciences, University of Frankfurt, Siesmayerstrasse 70, 60323 Frankfurt, Germany
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