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Lília M.a. Santos - One of the best experts on this subject based on the ideXlab platform.
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pigments from Eustigmatophyceae an interesting class of microalgae for carotenoid production
Journal of Applied Phycology, 2021Co-Authors: Raquel Amaral, Sergio Seixas J De Melo, Lília M.a. SantosAbstract:Pigments are a fundamental part of the microalgal cell, with chlorophylls at the center of photosynthesis and carotenoids as accessory pigments. The characteristic pigment profile of the Eustigmatophyceae was one of the evidences which contributed to the segregation of this class of organisms from the Xanthophyceae. Recent findings indicate that eustigmatophyte carotenoids are interesting compounds with laboratory-scale proven health-promoting effects but only a few studies dedicate to the characterization of the pigment profile of the class. In the present work, extracts of 27 eustigmatophyte strains held at the Coimbra Collection of Algae (ACOI) were prepared and analyzed by HPLC-DAD. Results showed a typical eustigmatophyte pigment profile present in all strains, namely, chlorophyll a, violaxanthin, vaucheriaxanthin diester, β,β-carotene, and other minor carotenoids. Violaxanthin was the most abundant carotenoid, achieving nearly half the total pigment content in Monodopsis unipapilla ACOI 2938, and also in two studied Vischeria strains, representing ca. 70% of carotenoids in both strains. The second major carotenoid was β,β-carotene, with the highest production of this commercially important carotenoid detected in Pseudostaurastrum sp. ACOI 3413 (24% of total pigments. Characiopsis cf. saccata ACOI 481 and Characiopsis minuta ACOI 2423 had the highest amount of vaucheriaxanthin diester (19% of total pigments). To our best knowledge, this represents the first report where the pigment profile of eustigmatophytes with stipitate Characiopsis-like morphology is characterized. The results reveal the high potential use of eustigmatophytes as sources of naturally derived carotenoids.
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Characiopsis Borzì belongs to the Eustigmatophyceae
European Journal of Phycology, 2020Co-Authors: Raquel Amaral, Tereza Ševčíková, Marek Eliáš, Lília M.a. SantosAbstract:Characiopsis, established by Borzi in 1895, is the largest genus traditionally classified in the class Xanthophyceae. However, Characiopsis-like algae studied over the last five decades using trans...
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a combined reflection confocal laser scanning electron and fluorescence microscopy analysis of the eyespot in zoospores of vischeria spp eustigmatales Eustigmatophyceae
Phycologia, 1996Co-Authors: Lília M.a. Santos, Michael Melkonian, Georg KreimerAbstract:The reflective properties of the extraplastidic eyespot in zoospores of Vischeria spp. (Eustigmatophyceae) were investigated using confocal laser scanning microscopy in the epireflection contrast m...
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Vischeria stellata (Eustigmatophyceae): ultrastructure of the zoospores, with special reference to the flagellar apparatus
The Cytoskeleton of Flagellate and Ciliate Protists, 1991Co-Authors: Lília M.a. Santos, G. F. LeedaleAbstract:Ultrastructure of the zoospores of Vischeria stellata (R. Chodat ex Poulton) Pascher is investigated, with particular reference to the system of flagellar roots. Microtubular roots and a rhizoplast are present and a model showing their distribution is proposed. Four microtubular roots attach to the basal bodies in a system basically similar to that displayed by the heterokont algae and fungi. The rhizoplast is also similar to that of other heterokont algae. We conclude from these observations that the class Eustigmatophyceae should be placed within the division Heterokontophyta.
Robert A Andersen - One of the best experts on this subject based on the ideXlab platform.
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Supermatrix Data Highlight the Phylogenetic Relationships of Photosynthetic Stramenopiles
Protist, 2011Co-Authors: Eun Chan Yang, Robert A Andersen, Ga Hun Boo, Hee Jeong Kim, Sung Mi Cho, Sung Min Boo, Hwan Su YoonAbstract:Molecular data had consistently recovered monophyletic classes for the heterokont algae, however, the relationships among the classes had remained only partially resolved. Furthermore, earlier studies did not include representatives from all taxonomic classes. We used a five-gene (nuclear encoded SSU rRNA; plastid encoded rbcL, psaA, psbA, psbC) analysis with a subset of 89 taxa representing all 16 heterokont classes to infer a phylogenetic tree. There were three major clades. The Aurearenophyceae, Chrysomerophyceae, Phaeophyceae, Phaeothamniophyceae, Raphidophyceae, Schizocladiophyceae and Xanthophyceae formed the SI clade. The Chrysophyceae, Eustigmatophyceae, Pinguiophyceae, Synchromophyceae and Synurophyceae formed the SII clade. The Bacillariophyceae, Bolidophyceae, Dictyochophyceae and Pelagophyceae formed the SIII clade. These three clades were also found in a ten-gene analysis. The approximately unbiased test rejected alternative hypotheses that forced each class into either of the other two clades. Morphological and biochemical data were not available for all 89 taxa, however, existing data were consistent with the molecular phylogenetic tree, especially for the SIII clade.
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Phylogeny of the Eustigmatophyceae Based upon 18S rDNA, with Emphasis on Nannochloropsis.
Protist, 1998Co-Authors: Robert A Andersen, Robyn W. Brett, Daniel Potter, Julianne P. SextonAbstract:Complete 18S rDNA sequences were determined for 25 strains representing five genera of the Eustigmatophyceae, including re-examination of three strains with previously published sequences. Parsimony analysis of these and 44 published sequences for other heterokont chromophytes (unalignable sites removed) revealed that the Eustigmatophyceae were a monophyletic group. Analysis of eustigmatophyte taxa only (complete gene analyzed) supported the current familial classification scheme. Twenty one strains of Nannochloropsis were also examined using light microscopy. Gross morphology of cells was variable and overlapped among the strains; cell size was consistent within strains but sometimes varied considerably among strains of a species. The 18S rDNA of N. gaditana, N. oculata and N. salina was re-sequenced for strains used in previous publications and one or more nucleotide differences were found. Nucleotide sequences for Nannochloropsis species varied by up to 32 nucleotides. Identical sequences were found for six strains of N. salina, five strains of N. gadifana, four strains of N. granulata, and two strains of N. oculata, respectively. Four strains could not be assigned to described species and may represent two new species. The unique 18S rDNA sequences for each sibling species of Nannochloropsis demonstrates the presence of considerable genetic diversity despite the extremely simple morphology in this genus.
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Ultrastructure, pigment composition, and 18S rRNA gene sequence for Nannochloropsis granulata sp. nov. (Monodopsidaceae, Eustigmatophyceae), a marine ultraplankter isolated from the Skagerrak, northeast Atlantic Ocean
Phycologia, 1996Co-Authors: B. Karlson, D. Potter, M. Kuylenstierna, Robert A AndersenAbstract:Abstract A marine ultraplankter, Nannochloropsis granulata sp. nov. (Eustigmatophyceae), was isolated from 17 m depth at a position north of Skagen, Denmark, in the Skagerrak, adjacent to the North Sea. Its ultrastructure, pigment composition, and the 18S rRNA gene sequence was studied and compared with N. oculata (Droop) Hibberd and N. salina Hibberd. The new species lacked both a pyrenoid and the lamellate vesicles present in the chloroplasts of the other two species. N. granulata had electron-dense bodies in the cytoplasm that did not resemble structures found in the other species. The red body characteristic of N. oculata was not observed in N. granulata. Remains of cell walls were conspicuous in old cultures of all three species. The pigment composition in all three species was very similar, with violaxanthin and a vaucheriaxanthin-like pigment as the dominating carotenoids. Based upon the alignment presented for the 18S rRNA gene, there were 9 nucleotide substitutions and 2 insertions/deletions betw...
Alejandro Maass - One of the best experts on this subject based on the ideXlab platform.
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Reconstruction of the microalga Nannochloropsis salina genome-scale metabolic model with applications to lipid production.
BMC systems biology, 2017Co-Authors: Nicolás Loira, Sebastián N. Mendoza, María Paz Cortés, Natalia Rojas, Dante Travisany, Alex Di Genova, Natalia Gajardo, Nicole Ehrenfeld, Alejandro MaassAbstract:Nannochloropsis salina (= Eustigmatophyceae) is a marine microalga which has become a biotechnological target because of its high capacity to produce polyunsaturated fatty acids and triacylglycerols. It has been used as a source of biofuel, pigments and food supplements, like Omega 3. Only some Nannochloropsis species have been sequenced, but none of them benefit from a genome-scale metabolic model (GSMM), able to predict its metabolic capabilities. We present iNS934, the first GSMM for N. salina, including 2345 reactions, 934 genes and an exhaustive description of lipid and nitrogen metabolism. iNS934 has a 90% of accuracy when making simple growth/no-growth predictions and has a 15% error rate in predicting growth rates in different experimental conditions. Moreover, iNS934 allowed us to propose 82 different knockout strategies for strain optimization of triacylglycerols. iNS934 provides a powerful tool for metabolic improvement, allowing predictions and simulations of N. salina metabolism under different media and genetic conditions. It also provides a systemic view of N. salina metabolism, potentially guiding research and providing context to -omics data.
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Reconstruction of the microalga Nannochloropsis salina genome-scale metabolic model with applications to lipid production
BMC, 2017Co-Authors: Nicolás Loira, María Paz Cortés, Natalia Rojas, Dante Travisany, Alex Di Genova, Natalia Gajardo, Nicole Ehrenfeld, Sebastian Mendoza, Alejandro MaassAbstract:Abstract Background Nannochloropsis salina (= Eustigmatophyceae) is a marine microalga which has become a biotechnological target because of its high capacity to produce polyunsaturated fatty acids and triacylglycerols. It has been used as a source of biofuel, pigments and food supplements, like Omega 3. Only some Nannochloropsis species have been sequenced, but none of them benefit from a genome-scale metabolic model (GSMM), able to predict its metabolic capabilities. Results We present iNS934, the first GSMM for N. salina, including 2345 reactions, 934 genes and an exhaustive description of lipid and nitrogen metabolism. iNS934 has a 90% of accuracy when making simple growth/no-growth predictions and has a 15% error rate in predicting growth rates in different experimental conditions. Moreover, iNS934 allowed us to propose 82 different knockout strategies for strain optimization of triacylglycerols. Conclusions iNS934 provides a powerful tool for metabolic improvement, allowing predictions and simulations of N. salina metabolism under different media and genetic conditions. It also provides a systemic view of N. salina metabolism, potentially guiding research and providing context to -omics data
Pavel Přibyl - One of the best experts on this subject based on the ideXlab platform.
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Screening for heterotrophy in microalgae of various taxonomic positions and potential of mixotrophy for production of high-value compounds
Journal of Applied Phycology, 2019Co-Authors: Pavel Přibyl, Vladislav CepákAbstract:We tested 37 photoautotrophic microalgal strains of various taxonomic positions for their heterotrophic growth on glucose. We showed that facultative heterotrophy was quite common among certain groups of green algae (Chlorellales or Sphaeropleales) and of Xanthophyceae, whereas it was completely absent from Eustigmatophyceae. For the first time, we found heterotrophy in some members of green algae ( Botryosphaerella sudetica , Bracteacoccus sp., Dictyosphaerium spp., Lemmermannia sp., Parachlorella kessleri ). Of the tested facultative heterotrophs, three strains, Scenedesmus sp., Dictyosphaerium chlorelloides , and Tribonema aequale , were selected to investigate, in detail, their mixotrophic growth and production of specific metabolites, carotenoids, exopolysaccharides, and eicosapentaenoic acid, respectively. Among them only T . aequale showed significantly higher production of the target compound, eicosapentaenoic acid, under the mixotrophic cultivation mode than photoautotrophically. Together with the ease of biomass harvest, Tribonema microalgae are therefore proposed as a possible source of high-quality ω-3 polyunsaturated fatty acids.
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ZOOSPOROGENESIS, MORPHOLOGY, ULTRASTRUCTURE, PIGMENT COMPOSITION, AND PHYLOGENETIC POSITION OF TRACHYDISCUS MINUTUS (Eustigmatophyceae, HETEROKONTOPHYTA)(1).
Journal of phycology, 2012Co-Authors: Pavel Přibyl, Vladislav Cepák, Marek Eliáš, Jaromír Lukavský, Petr KaštánekAbstract:The traditional order Mischococcales (Xanthophyceae) is polyphyletic with some original members now classified in a separate class, Eustigmatophyceae. However, most mischococcalean species have not yet been studied in detail, raising the possibility that many of them still remain misplaced. We established an algal culture (strain CCALA 838) determined as one such species, Trachydiscus minutus (Bourr.) H. Ettl, and studied the morphology, ultrastructure, life cycle, pigment composition, and phylogeny using the 18S rRNA gene. We discovered a zoosporic part of the life cycle of this alga. Zoospore production was induced by darkness, suppressed by light, and was temperature dependent. The zoospores possessed one flagellum covered with mastigonemes and exhibited a basal swelling, but a stigma was missing. Ultrastructural investigations of vegetative cells revealed plastids lacking both a connection to the nuclear envelope and a girdle lamella. Moreover, we described biogenesis of oil bodies on the ultrastructural level. Photosynthetic pigments of T. minutus included as the major carotenoids violaxanthin and vaucheriaxanthin (ester); we detected no chl c. An 18S rRNA gene-based phylogenetic analysis placed T. minutus in a clade with species of the genus Pseudostaurastrum and with Goniochloris sculpta Geitler, which form a sister branch to initially studied Eustigmatophyceae. In summary, our results are inconsistent with classifying T. minutus as a xanthophycean and indicate that it is a member of a novel deep lineage of the class Eustigmatophyceae.
Vladislav Cepák - One of the best experts on this subject based on the ideXlab platform.
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Screening for heterotrophy in microalgae of various taxonomic positions and potential of mixotrophy for production of high-value compounds
Journal of Applied Phycology, 2019Co-Authors: Pavel Přibyl, Vladislav CepákAbstract:We tested 37 photoautotrophic microalgal strains of various taxonomic positions for their heterotrophic growth on glucose. We showed that facultative heterotrophy was quite common among certain groups of green algae (Chlorellales or Sphaeropleales) and of Xanthophyceae, whereas it was completely absent from Eustigmatophyceae. For the first time, we found heterotrophy in some members of green algae ( Botryosphaerella sudetica , Bracteacoccus sp., Dictyosphaerium spp., Lemmermannia sp., Parachlorella kessleri ). Of the tested facultative heterotrophs, three strains, Scenedesmus sp., Dictyosphaerium chlorelloides , and Tribonema aequale , were selected to investigate, in detail, their mixotrophic growth and production of specific metabolites, carotenoids, exopolysaccharides, and eicosapentaenoic acid, respectively. Among them only T . aequale showed significantly higher production of the target compound, eicosapentaenoic acid, under the mixotrophic cultivation mode than photoautotrophically. Together with the ease of biomass harvest, Tribonema microalgae are therefore proposed as a possible source of high-quality ω-3 polyunsaturated fatty acids.
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ZOOSPOROGENESIS, MORPHOLOGY, ULTRASTRUCTURE, PIGMENT COMPOSITION, AND PHYLOGENETIC POSITION OF TRACHYDISCUS MINUTUS (Eustigmatophyceae, HETEROKONTOPHYTA)(1).
Journal of phycology, 2012Co-Authors: Pavel Přibyl, Vladislav Cepák, Marek Eliáš, Jaromír Lukavský, Petr KaštánekAbstract:The traditional order Mischococcales (Xanthophyceae) is polyphyletic with some original members now classified in a separate class, Eustigmatophyceae. However, most mischococcalean species have not yet been studied in detail, raising the possibility that many of them still remain misplaced. We established an algal culture (strain CCALA 838) determined as one such species, Trachydiscus minutus (Bourr.) H. Ettl, and studied the morphology, ultrastructure, life cycle, pigment composition, and phylogeny using the 18S rRNA gene. We discovered a zoosporic part of the life cycle of this alga. Zoospore production was induced by darkness, suppressed by light, and was temperature dependent. The zoospores possessed one flagellum covered with mastigonemes and exhibited a basal swelling, but a stigma was missing. Ultrastructural investigations of vegetative cells revealed plastids lacking both a connection to the nuclear envelope and a girdle lamella. Moreover, we described biogenesis of oil bodies on the ultrastructural level. Photosynthetic pigments of T. minutus included as the major carotenoids violaxanthin and vaucheriaxanthin (ester); we detected no chl c. An 18S rRNA gene-based phylogenetic analysis placed T. minutus in a clade with species of the genus Pseudostaurastrum and with Goniochloris sculpta Geitler, which form a sister branch to initially studied Eustigmatophyceae. In summary, our results are inconsistent with classifying T. minutus as a xanthophycean and indicate that it is a member of a novel deep lineage of the class Eustigmatophyceae.
