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Wolfgang Loffelhardt - One of the best experts on this subject based on the ideXlab platform.
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758 The central body of the cyanelles of Cyanophora paradoxa: a eukaryotic carboxysome? 1
2013Co-Authors: Suzanne C Burey, Wolfgang Loffelhardt, V Poroyko, S. Fathi-nejad, J. M. Steiner, H. J. BohnertAbstract:Abstract: The cyanelles of the glaucocystophyte Cyanophora paradoxa combine two prokaryotic features not found in other phototrophic eukaryotes: a peptidoglycan wall and a putative carboxysome. Both of them would be indispensable when a inorganic carbon concentrating mechanism involving high accumulation of bicarbonate in the cyanelle stroma is assumed. Two approaches were used. (i) An expressed sequence tag library was generated allowing access to interesting genes and microarray technology. Hybridization of the microarrays to RNA from cells grown at high and low CO 2 yielded 97 genes that were upregulated under CO 2 stress whereas 87 genes were found to be downregulated. (ii) Cyanelle central bodies were isolated and protein components other than Rubisco were investigated by mass spectrometry. So far, mass spectrometric analysis of putative carboxysomal proteins yielded only sequences with no match in the databases. Rubisco activase could be shown via in vitro import and Western blotting to be copackaged with Rubisco in isolated purified central bodies. While our data support the presence of an inorganic carbon concentrating mechanism in cyanelles, they do not allow us to distinguish the microcompartment as a carboxysome or pyrenoid
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Analysis of the Genome of Cyanophora paradoxa : An Algal Model for Understanding Primary Endosymbiosis
Endosymbiosis, 2013Co-Authors: Debashish Bhattacharya, Dana C. Price, Jürgen M. Steiner, Cheong Xin Chan, Jeferson Gross, Wolfgang LoffelhardtAbstract:Algae and plants rely on the plastid (e.g., chloroplast) to carry out photosynthesis. This organelle traces its origin to a cyanobacterium that was captured over a billion years ago by a single-celled protist. Three major photosynthetic lineages (the green algae and plants [Viridiplantae], red algae [Rhodophyta], and Glaucophyta) arose from this primary endosymbiotic event and are putatively united as the Plantae (also known as Archaeplastida). Glaucophytes comprise a handful of poorly studied species that retain ancestral features of the cyanobacterial endosymbiont such as a peptidoglycan cell wall. Testing the Plantae hypothesis and elucidating glaucophyte evolution has in the past been thwarted by the absence of complete genome data from these taxa. Furthermore, multigene phylogenetics has fueled controversy about the frequency of primary plastid acquisitions during eukaryote evolution because these approaches have generally failed to recover Plantae monophyly and often provide conflicting results. Here, we review some of the key insights about Plantae evolution that were gleaned from a recent analysis of a draft genome assembly from Cyanophora paradoxa (Glaucophyta). We present results that conclusively demonstrate Plantae monophyly. We also describe new insights that were gained into peptidoglycan biosynthesis in glaucophytes and the carbon concentrating mechanism (CCM) in C. paradoxa plastids.
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Conservative sorting in the muroplasts of Cyanophora paradoxa: a reevaluation based on the completed genome sequence
Symbiosis, 2012Co-Authors: Jürgen M. Steiner, Debashish Bhattacharya, Wolfgang LoffelhardtAbstract:After primary endosymbiosis, massive gene transfer occurred from the genome of the cyanobacterial endosymbiont to the nucleus of the protist host cell. In parallel, a specific protein import apparatus arose for reimport of many, but not all products of the genes moved to the nuclear genome. Presequences evolved to allow recognition of plastid proteins at the envelope and their translocation to the stroma. However, plastids (and cyanobacteria) also comprise five other subcompartments. Protein sorting to the cyanobacterial thylakoid membrane, the thylakoid lumen, the inner envelope membrane, the periplasmic space, and the outer envelope membrane is achieved by prokaryotic protein translocases recognizing, e.g., signal sequences. The “conservative sorting” hypothesis postulates that these translocases remained functional in endosymbiotic organelles and obtained their passengers not only from imported proteins but also from proteins synthesized in organello . For proteins synthesized in the cytosol, a collaboration of the general import apparatus and the former prokaryotic translocase is necessary which is often reflected by the use of bipartite presequences, e.g., stroma targeting peptide and signal peptide. For plants, this concept has been experimentally proven and verified. The muroplasts from Cyanophora paradoxa , that have several features more in common with cyanobacteria than with plastids, were analyzed with the availability of the recently completed nuclear genome sequence. Interesting findings include the absence of the post-translational signal recognition particle pathway, dual Sec translocases in thylakoid and inner envelope membranes that are produced from a single set of genes, and a co-translational signal recognition pathway operating without a 4.5S RNA component.
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the photosynthetic apparatus of the living fossil Cyanophora paradoxa
2011Co-Authors: Jürgen M. Steiner, Wolfgang LoffelhardtAbstract:Muroplasts, the peculiar plastids (previously called cyanelles) of glaucocystophyte algae did retain—with some modifications—the peptidoglycan wall of their cyanobacterial ancestor. This is not only a convincing proof of the endosymbiotic theory, but earns glaucocystophytes the status of living fossils, as peptidoglycan is found nowhere else among eukaryotes. Muroplasts show even more cyanobacterial features than other primitive plastids, e.g., rhodoplasts. Almost all data available at present come from one species, Cyanophora paradoxa. The plastome, containing a surplus of 50 protein genes compared to chloroplast genomes (Table 2.1) and about 30% of the transcriptome (ESTs) of this organism are sequenced and a genome project is in progress. While Cyanophora does not offer such possibilities for genetic analysis as the Chlamydomonas system, due to its reasonable growth rate it is amenable to biochemical investigations.
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evolutionary conservation of dual sec translocases in the cyanelles of Cyanophora paradoxa
BMC Evolutionary Biology, 2008Co-Authors: Fumie Yusa, Jürgen M. Steiner, Wolfgang LoffelhardtAbstract:Cyanelles, the peptidoglycan-armored plastids of glaucocystophytes, occupy a unique bridge position in between free-living cyanobacteria and chloroplasts. In some respects they side with cyanobacteria whereas other features are clearly shared with chloroplasts. The Sec translocase, an example for "conservative sorting" in the course of evolution, is found in the plasma membrane of all prokaryotes, in the thylakoid membrane of chloroplasts and in both these membrane types of cyanobacteria. In this paper we present evidence for a dual location of the Sec translocon in the thylakoid as well as inner envelope membranes of the cyanelles from Cyanophora paradoxa, i. e. conservative sorting sensu stricto. The prerequisite was the generation of specific antisera directed against cyanelle SecY that allowed immunodetection of the protein on SDS gels from both membrane types separated by sucrose density gradient floatation centrifugation. Immunoblotting of blue-native gels yielded positive but differential results for both the thylakoid and envelope Sec complexes, respectively. In addition, heterologous antisera directed against components of the Toc/Tic translocons and binding of a labeled precursor protein were used to discriminate between inner and outer envelope membranes. The envelope translocase can be envisaged as a prokaryotic feature missing in higher plant chloroplasts but retained in cyanelles, likely for protein transport to the periplasm. Candidate passengers are cytochrome c6 and enzymes of peptidoglycan metabolism. The minimal set of subunits of the Toc/Tic translocase of a primitive plastid is proposed.
Jürgen M. Steiner - One of the best experts on this subject based on the ideXlab platform.
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Identification of protein N-termini in Cyanophora paradoxa cyanelles: transit peptide composition and sequence determinants for precursor maturation.
Frontiers in Plant Science, 2015Co-Authors: Daniel Köhler, Jürgen M. Steiner, Wolfgang Hoehenwarter, Stefan Helm, Dirk Dobritzsch, Sacha BaginskyAbstract:Glaucophyta, rhodophyta and chloroplastida represent the three main evolutionary lineages that diverged from a common ancestor after primary endosymbiosis. Comparative analyses between members of these three lineages are a rich source of information on ancestral plastid features. We analyzed the composition and the cleavage site of cyanelle transit peptides from the glaucophyte Cyanophora paradoxa by terminal amine labelling of substrates (TAILS), and compared their characteristics to those of representatives of the chloroplastida. Our data show that transit peptide architecture is similar between members of these two lineages. This entails a comparable modular structure, an overrepresentation of serine or alanine and similarities in the amino acid composition around the processing peptidase cleavage site. The most distinctive difference is the overrepresentation of phenylalanine in the N-terminal 1-10 amino acids of cyanelle transit peptides. A quantitative proteome analysis with periplasm-free cyanelles identified 42 out of 262 proteins without the N-terminal phenylalanine, suggesting that the requirement for phenylalanine in the N-terminal region is not absolute. Proteins in this set are on average of low abundance, suggesting that either alternative import pathways are operating specifically for low abundance proteins or that the gene model annotation is incorrect for proteins with fewer EST sequences. We discuss these two possibilities and provide examples for both interpretations.
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Analysis of the Genome of Cyanophora paradoxa : An Algal Model for Understanding Primary Endosymbiosis
Endosymbiosis, 2013Co-Authors: Debashish Bhattacharya, Dana C. Price, Jürgen M. Steiner, Cheong Xin Chan, Jeferson Gross, Wolfgang LoffelhardtAbstract:Algae and plants rely on the plastid (e.g., chloroplast) to carry out photosynthesis. This organelle traces its origin to a cyanobacterium that was captured over a billion years ago by a single-celled protist. Three major photosynthetic lineages (the green algae and plants [Viridiplantae], red algae [Rhodophyta], and Glaucophyta) arose from this primary endosymbiotic event and are putatively united as the Plantae (also known as Archaeplastida). Glaucophytes comprise a handful of poorly studied species that retain ancestral features of the cyanobacterial endosymbiont such as a peptidoglycan cell wall. Testing the Plantae hypothesis and elucidating glaucophyte evolution has in the past been thwarted by the absence of complete genome data from these taxa. Furthermore, multigene phylogenetics has fueled controversy about the frequency of primary plastid acquisitions during eukaryote evolution because these approaches have generally failed to recover Plantae monophyly and often provide conflicting results. Here, we review some of the key insights about Plantae evolution that were gleaned from a recent analysis of a draft genome assembly from Cyanophora paradoxa (Glaucophyta). We present results that conclusively demonstrate Plantae monophyly. We also describe new insights that were gained into peptidoglycan biosynthesis in glaucophytes and the carbon concentrating mechanism (CCM) in C. paradoxa plastids.
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Conservative sorting in the muroplasts of Cyanophora paradoxa: a reevaluation based on the completed genome sequence
Symbiosis, 2012Co-Authors: Jürgen M. Steiner, Debashish Bhattacharya, Wolfgang LoffelhardtAbstract:After primary endosymbiosis, massive gene transfer occurred from the genome of the cyanobacterial endosymbiont to the nucleus of the protist host cell. In parallel, a specific protein import apparatus arose for reimport of many, but not all products of the genes moved to the nuclear genome. Presequences evolved to allow recognition of plastid proteins at the envelope and their translocation to the stroma. However, plastids (and cyanobacteria) also comprise five other subcompartments. Protein sorting to the cyanobacterial thylakoid membrane, the thylakoid lumen, the inner envelope membrane, the periplasmic space, and the outer envelope membrane is achieved by prokaryotic protein translocases recognizing, e.g., signal sequences. The “conservative sorting” hypothesis postulates that these translocases remained functional in endosymbiotic organelles and obtained their passengers not only from imported proteins but also from proteins synthesized in organello . For proteins synthesized in the cytosol, a collaboration of the general import apparatus and the former prokaryotic translocase is necessary which is often reflected by the use of bipartite presequences, e.g., stroma targeting peptide and signal peptide. For plants, this concept has been experimentally proven and verified. The muroplasts from Cyanophora paradoxa , that have several features more in common with cyanobacteria than with plastids, were analyzed with the availability of the recently completed nuclear genome sequence. Interesting findings include the absence of the post-translational signal recognition particle pathway, dual Sec translocases in thylakoid and inner envelope membranes that are produced from a single set of genes, and a co-translational signal recognition pathway operating without a 4.5S RNA component.
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the photosynthetic apparatus of the living fossil Cyanophora paradoxa
2011Co-Authors: Jürgen M. Steiner, Wolfgang LoffelhardtAbstract:Muroplasts, the peculiar plastids (previously called cyanelles) of glaucocystophyte algae did retain—with some modifications—the peptidoglycan wall of their cyanobacterial ancestor. This is not only a convincing proof of the endosymbiotic theory, but earns glaucocystophytes the status of living fossils, as peptidoglycan is found nowhere else among eukaryotes. Muroplasts show even more cyanobacterial features than other primitive plastids, e.g., rhodoplasts. Almost all data available at present come from one species, Cyanophora paradoxa. The plastome, containing a surplus of 50 protein genes compared to chloroplast genomes (Table 2.1) and about 30% of the transcriptome (ESTs) of this organism are sequenced and a genome project is in progress. While Cyanophora does not offer such possibilities for genetic analysis as the Chlamydomonas system, due to its reasonable growth rate it is amenable to biochemical investigations.
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Evolutionary conservation of dual Sec translocases in the cyanelles of Cyanophora paradoxa
BMC Evolutionary Biology, 2008Co-Authors: Fumie Yusa, Jürgen M. Steiner, Wolfgang LoffelhardtAbstract:Background Cyanelles, the peptidoglycan-armored plastids of glaucocystophytes, occupy a unique bridge position in between free-living cyanobacteria and chloroplasts. In some respects they side with cyanobacteria whereas other features are clearly shared with chloroplasts. The Sec translocase, an example for "conservative sorting" in the course of evolution, is found in the plasma membrane of all prokaryotes, in the thylakoid membrane of chloroplasts and in both these membrane types of cyanobacteria. Results In this paper we present evidence for a dual location of the Sec translocon in the thylakoid as well as inner envelope membranes of the cyanelles from Cyanophora paradoxa , i. e. conservative sorting sensu stricto . The prerequisite was the generation of specific antisera directed against cyanelle SecY that allowed immunodetection of the protein on SDS gels from both membrane types separated by sucrose density gradient floatation centrifugation. Immunoblotting of blue-native gels yielded positive but differential results for both the thylakoid and envelope Sec complexes, respectively. In addition, heterologous antisera directed against components of the Toc/Tic translocons and binding of a labeled precursor protein were used to discriminate between inner and outer envelope membranes. Conclusion The envelope translocase can be envisaged as a prokaryotic feature missing in higher plant chloroplasts but retained in cyanelles, likely for protein transport to the periplasm. Candidate passengers are cytochrome c _6 and enzymes of peptidoglycan metabolism. The minimal set of subunits of the Toc/Tic translocase of a primitive plastid is proposed.
Marek Mutwil - One of the best experts on this subject based on the ideXlab platform.
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gene expression analysis of Cyanophora paradoxa reveals conserved abiotic stress responses between basal algae and flowering plants
New Phytologist, 2020Co-Authors: Camilla Ferrari, Marek MutwilAbstract:: The glaucophyte Cyanophora paradoxa represents the most basal member of the kingdom Archaeplastida, but the function and expression of most of its genes are unknown. This information is needed to uncover how functional gene modules, that is groups of genes performing a given function, evolved in the plant kingdom. We have generated a gene expression atlas capturing responses of Cyanophora to various abiotic stresses. The data were included in the CoNekT-Plants database, enabling comparative transcriptomic analyses across two algae and six land plants. We demonstrate how the database can be used to study gene expression, co-expression networks and gene function in Cyanophora, and how conserved transcriptional programs can be identified. We identified gene modules involved in phycobilisome biosynthesis, response to high light and cell division. While we observed no correlation between the number of differentially expressed genes and the impact on growth of Cyanophora, we found that the response to stress involves a conserved, kingdom-wide transcriptional reprogramming, which is activated upon most stresses in algae and land plants. The Cyanophora stress gene expression atlas and the tools found in the https://conekt.plant.tools/ database thus provide a useful resource to reveal functionally related genes and stress responses in the plant kingdom.
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gene expression analysis of Cyanophora paradoxa reveals conserved abiotic stress responses between basal algae and flowering plants
bioRxiv, 2019Co-Authors: Camilla Ferrari, Marek MutwilAbstract:O_LIThe glaucophyte Cyanophora paradoxa represents the most basal member of the Archaeplastida kingdom, however the function and expression of most of its genes are unknown. This information is needed to uncover how functional gene modules, i.e. groups of genes performing a given function, evolved in the plant kingdom.nC_LIO_LIWe have generated a gene expression atlas capturing responses of Cyanophora to various abiotic stresses. This data was included in the CoNekT-Plants database, enabling comparative transcriptomic analyses across two algae and six land plants.nC_LIO_LIWe demonstrate how the database can be used to study gene expression, co-expression networks and gene function in Cyanophora, and how conserved transcriptional programs can be identified. We identified gene modules involved in phycobilisome biosynthesis, response to high light and cell division. While we observed no correlation between the number of differentially expressed genes and the impact on growth of Cyanophora, we found that the response to stress involves a conserved, kingdom-wide transcriptional reprogramming, which is activated upon most stresses in algae and land plants.nC_LIO_LIThe Cyanophora stress gene expression atlas and the tools found in https://conekt.plant.tools/ database provide a useful resource to reveal functionally related genes and stress responses in the plant kingdom.nC_LI
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Analysis of an improved Cyanophora paradoxa genome assembly.
DNA Research, 2019Co-Authors: Dana C. Price, Ursula Goodenough, Camilla Ferrari, Fabio Facchinelli, Marek Mutwil, Robyn Roth, Thamali Kariyawasam, Steven G Ball, Ugo CenciAbstract:Glaucophyta are members of the Archaeplastida, the founding group of photosynthetic eukaryotes that also includes red algae (Rhodophyta), green algae, and plants (Viridiplantae). Here we present a high-quality assembly, built using long-read sequences, of the ca. 100 Mb nuclear genome of the model glaucophyte Cyanophora paradoxa. We also conducted a quick-freeze deep-etch electron microscopy (QFDEEM) analysis of C. paradoxa cells to investigate glaucophyte morphology in comparison to other organisms. Using the genome data, we generated a resolved 115-taxon eukaryotic tree of life that includes a well-supported, monophyletic Archaeplastida. Analysis of muroplast peptidoglycan (PG) ultrastructure using QFDEEM shows that PG is most dense at the cleavage-furrow. Analysis of the chlamydial contribution to glaucophytes and other Archaeplastida shows that these foreign sequences likely played a key role in anaerobic glycolysis in primordial algae to alleviate ATP starvation under night-time hypoxia. The robust genome assembly of C. paradoxa significantly advances knowledge about this model species and provides a reference for exploring the panoply of traits associated with the anciently diverged glaucophyte lineage.
Hans J. Bohnert - One of the best experts on this subject based on the ideXlab platform.
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acclimation to low co2 by an inorganic carbon concentrating mechanism in Cyanophora paradoxa
Plant Cell and Environment, 2007Co-Authors: Suzanne C Burey, V Poroyko, Z N Ergen, Sara Fathinejad, C Schuller, Norikazu Ohnishi, Hans J. Bohnert, Hideya Fukuzawa, Wolfgang LoffelhardtAbstract:The glaucocystophyte Cyanophora paradoxa contains cyanelles, plastids with prokaroytic features such as a pepti- doglycan wall and a central proteinaceous inclusion body. While this central body includes the majority of the enzyme ribulose 1,5-bisphosphate carboxylase/oxgenase Rubisco), the presence of a carbon-concentrating mechanism (CCM) in C. paradoxa has only been hypothesized. Here, we present physiological data in support of a CCM: CO2 exchange activity as well as apparent affinity against inor- ganic carbon were found to increase under CO2-limiting stress. Further, expressed sequence tags (ESTs) of C. para- doxawereobtainedfromtwocDNAlibraries,onefromcells grown in high (CO2) conditions and one from cells grown under low (CO2) conditions. A cDNA microarray platform assembled from 2378 cDNA sequences revealed that 142 genes significantly responded to a shift from high to low (CO2).Trends in gene expression were comparable to those reported for Chlamydomonas reinhardtii and the cyano- bacterium Synechocystis 6803, both possessing a CCM. Amonggenesregulatedby(CO2),transcriptswereidentified encodingcarbonicanhydrases(CAs),Rubiscoactivaseanda putative bicarbonate transporter in C. paradoxa, likely functionally involved in the CCM. These results and the polyhedric appearance of the central body further support the hypothesis of a unique 'eukaryotic carboxysome' in Cyanophora.
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the central body of the cyanelles of Cyanophora paradoxa a eukaryotic carboxysome
Botany, 2005Co-Authors: Suzanne C Burey, Wolfgang Loffelhardt, Jürgen M. Steiner, V Poroyko, Sara Fathinejad, Hans J. BohnertAbstract:The cyanelles of the glaucocystophyte Cyanophora paradoxa combine two prokaryotic features not found in other phototrophic eukaryotes: a peptidoglycan wall and a putative carboxysome. Both of them would be indispensable when a inorganic carbon concentrating mechanism involving high accumulation of bicarbonate in the cyanelle stroma is assumed. Two approaches were used. (i) An expressed sequence tag library was generated allowing access to interest- ing genes and microarray technology. Hybridization of the microarrays to RNA from cells grown at high and low CO2 yielded 97 genes that were upregulated under CO2 stress whereas 87 genes were found to be downregulated. (ii) Cyanelle central bodies were isolated and protein components other than Rubisco were investigated by mass spec- trometry. So far, mass spectrometric analysis of putative carboxysomal proteins yielded only sequences with no match in the databases. Rubisco activase could be shown via in vitro import and Western blotting to be copackaged with Rubisco in isolated purified central bodies. While our data support the presence of an inorganic carbon concentrating mechanism in cyanelles, they do not allow us to distinguish the microcompartment as a carboxysome or pyrenoid.
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the subcellular localization of dna components from Cyanophora paradoxa a flagellate containing endosymbiotic cyanelles
FEBS Journal, 2005Co-Authors: Hans J. Bohnert, Edwin J Crouse, Jean Pouyet, Herrmann Mucke, Wolfgang LoffelhardtAbstract:Cyanophora paradoxa, a unicellular flagellate, contains cyanelles which are supposed to be cyanobacterial origin. DNA was isolated from subcellular fractions and separated according to density components in CsCl density gradients. The main DNA component, comprising more than 90% of the total DNA, has a buoyant density of 1.724 g · cm−3. Several subsfractions in the range from 1.718 g · cm−3 to 1.735 g · cm−3 are contained in this component. This DNA of high complexity was considered to be host nuclear DNA. The DNA from the endosymbiotic cyanelles, which were isolated, treated with DNase, and purified by sucrose density gradient centrifugation exhibited a buoyant density of 1.692 g · cm−3 in one strain and 1.695 g · cm−3 in a second strain. Both cyanelle DNAs (cyDNA) have a complexity of approximately 126 · 103 base pairs and comprise about 5% of the total cellular DNA content. Two additional DNA components of low complexity were isolated from crude cyanelle pellets obtained without DNase treatment. The larger of these, approximately 48 × 103 base pairs in size, had a density of approximately 1.688 g · cm−3. The second component, about 15 × 103 base pairs in size, banded in the density range between 1.710 g · cm−3 and 1.720 g · cm−3. The latter is associated with nuclear DNA. The 48 × 10−3 base-pair component was located in the cytosol and could be obtained after CsCl/ethidium bromide density gradient centrifugation at the position of covalently closed circular DNA. Both these components amounted to approximately 0.5–1% of total DNA. A further DNA component with a complexity of more than 150 × 103 base pairs, enriched in fractions where mitochondria are expected, was not characterized further. The density was intermediate between cyDNA and nuclear DNA (1.710–1.720 g · cm−3) and it amounted to 1–2% of the total DNA. Our results indicate that the DNA from cyanelles, believed to be endosymbiotic cyanobacteria, is not more complex than higher plant chloroplast DNAs.
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the cyanelles of Cyanophora paradoxa
Critical Reviews in Plant Sciences, 1997Co-Authors: Wolfgang Loffelhardt, Hans J. Bohnert, Donald A Bryant, Rudolf HagemannAbstract:Abstract The cyanelles of Cyanophora paradoxa, plastids surrounded by a peptidoglycan wall, are considered as a surviving example for an early stage of plastid evolution from endosymbiotic cyanobacteria. We highlight the model character of the system by focusing on three aspects: “organelle wall” structure, plastid genome organization, and protein translocation. The biosynthetic pathway for cyanelle peptidoglycan appears to be analogous to that in Escherichia coli. Also, the basic structure of this peculiar organelle wall corresponds to that of the E. coli sacculus, with one notable exception: the C-1 carboxyl group of the D-isoglutamyl residue is partially amidated with N-acetylputrescine. Cyanelles harbor on their completely sequenced 135.6-kb genome genes for approximately 150 polypeptides, many of which are nucleus encoded in higher plants. Nevertheless, there are striking parallels in genome organization between cyanelles (and other primitive plastids) and higher plant chloroplasts. The transit seque...
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the complete sequence of the Cyanophora paradoxa cyanelle genome glaucocystophyceae
1997Co-Authors: Wolfgang Loffelhardt, Hans J. Bohnert, Donald A BryantAbstract:The obligatorily autotrophic protist, Cyanophora paradoxa, harbors cyanelles, primitive plastids with the morphology and surrounding peptidoglycan sacculus of endosymbiotic cyanobacteria. The complete nucleotide sequence of the 135.6 kb cyanelle genome leaves no doubt about the plastid status of these unusual organelles. Peculiarities of genome organization that are found in cyanelles as well as in algal and higher plant chloroplasts support the hypothesis that all plastid types have a common origin (i.e., that only a singular primary endosymbiotic event occurred). The ancestral semiautonomous organelle, the protoplastid, would still have retained the prokaryotic wall in this scenario.
Charlotte Plancke - One of the best experts on this subject based on the ideXlab platform.
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etude du metabolisme de l amidon chez les archaeplastida le cas de l algue glaucophyte modele unicellulaire Cyanophora paradoxa et de l algue rouge multicellulaire chondrus crispus
2008Co-Authors: Charlotte PlanckeAbstract:L'amidon et le glycogene definissent les deux polysaccharides de reserve les plus repandus dans le monde vivant. L'apparition de l'amidon chez les eucaryotes coincide avec un evenement d'endosymbiose unique qui s'est deroule il y a 1,6 milliards d'annees entre une cyanobacterie et un eucaryote primitif. De cet evenement sont apparues trois lignees photosynthetiques : les Chloroplastida (plantes terrestres et algues vertes), les Rhodophyceae (algues rouges et organismes qui en sont derives par endosymbiose secondaire) et les Glaucophyta. La voie de biosynthese de l'amidon chloroplastique chez les Chloroplastida est relativement bien caracterisee. Pour celle des Rhodophyceae (amidon cytoplasmique) des etudes ont deja ete entreprises mais les informations obtenues sont encore incompletes et non representatives de la lignee en general. Enfin pour les Glaucophyta, qui ont diverge de facon plus precoce apres l'evenement d'endosymbiose aucune information sur le metabolisme de son amidon (cytoplasmique) n'etait disponible. Afin d'apprehender la voie de biosynthese utilisee par ces organismes nous avons entrepris la caracterisation de la voie metabolique de l'amidon de Cyanophora paradoxa (Glaucophyta) ainsi que celle de Chondrus crispus (Rhodophyceae). Ce manuscrit de these presente essentiellement des informations sur le metabolisme de l'amidon florideen chez Cyanophora paradoxa, l'etude entreprise chez Chondrus crispus etant encore a l'etat preliminaire.
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pathway of cytosolic starch synthesis in the model glaucophyte Cyanophora paradoxa
Eukaryotic Cell, 2008Co-Authors: Charlotte Plancke, Sophie Haebel, Gehrardt Ritte, Philippe Deschamps, David Dauvillee, Christophe Colleoni, Yasunori Nakamura, Alain Buléon, Martin Steup, Jean-luc PutauxAbstract:The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model glaucophyte Cyanophora paradoxa. The storage polysaccharide granules are shown to be composed of both amylose and amylopectin fractions, with a chain length distribution and crystalline organization similar to those of green algae and land plant starch. A preliminary characterization of the starch pathway demonstrates that Cyanophora paradoxa contains several UDP-glucose-utilizing soluble starch synthase activities related to those of the Rhodophyceae. In addition, Cyanophora paradoxa synthesizes amylose with a granule-bound starch synthase displaying a preference for UDP-glucose. A debranching enzyme of isoamylase specificity and multiple starch phosphorylases also are evidenced in the model glaucophyte. The picture emerging from our biochemical and molecular characterizations consists of the presence of a UDP-glucose-based pathway similar to that recently proposed for the red algae, the cryptophytes, and the alveolates. The correlative presence of isoamylase and starch among photosynthetic eukaryotes is discussed.
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THE PATHWAY OF CYTOSOLIC STARCH SYNTHESIS IN THE MODEL GLAUCOPHYTE Cyanophora paradoxa.
Eukaryotic Cell, 2007Co-Authors: Charlotte Plancke, Sophie Haebel, Gehrardt Ritte, Philippe Deschamps, David Dauvillee, Christophe Colleoni, Yasunori Nakamura, Alain Buléon, Martin Steup, Jean-luc PutauxAbstract:The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model glaucophyte Cyanophora paradoxa. The storage polysaccharide granules are shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization similar to those of green algae and land plant starch. Preliminary characterization of the starch pathway demonstrates that Cyanophora paradoxa contains several UDP-glucose utilising soluble starch synthase activities related to those of the rhodophyceae. In addition Cyanophora paradoxa synthesizes amylose with a granule-bound starch synthase displaying a preference for UDP-glucose. A debranching enzyme of isoamylase specificity and multiple starch phosphorylases are also evidenced in the model glaucophyte. The picture emerging from our biochemical and molecular characterizations consists of the presence of an UDP-glucose-based pathway similar to that recently proposed for the red algae, the cryptophytes and the alveolates. The correlative presence of isoamylase and starch among photosynthetic eukaryotes is discussed.
