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Kazuo Okuda - One of the best experts on this subject based on the ideXlab platform.
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development of thecal plates and pellicle in the dinoflagellate scrippsiella hexapraecingula peridiniales dinophyceae elucidated by changes in stainability of the associated membranes
European Journal of Phycology, 2004Co-Authors: Satoko Sekida, Takeo Horiguchi, Kazuo OkudaAbstract:The development of the pellicle and thecal plates of the dinoflagellate Scrippsiella hexapraecingula Horiguchi et Chihara was investigated with particular emphasis on cellulose synthesis. In young Motile Cells, incipient thecal plates appear as several groups of granular material within individual sites that are thought to be amphiesmal vesicles and develop into thin, sheet-like plates. These plates subsequently thicken with the deposition of amorphous material and cellulose microfibrils to form mature thecal plates. After ecdysis, non-Motile Cells form a pellicle consisting of three layers, L1-3. L1 is electron dense, while L2 and L3 are electron transparent. L1 and L2 are non-cellulosic, but L3 contains cellulose microfibrils. A new type of putative cellulose-synthesizing enzyme complex was found in non-Motile Cells. It consists of two rows of particles occurring on the plasmatic fracture face of the plasma membrane and begins to appear 0.5 – 1 h after ecdysis. The periodic acid-thiocarbohydrazide-silve...
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development of the cell covering in the dinoflagellate scrippsiella hexapraecingula peridiniales dinophyceae
Phycological Research, 2001Co-Authors: Satoko Sekida, Takeo Horiguchi, Kazuo OkudaAbstract:SUMMARY The organization and development of cell coverings in two alternate phases of the life cycle in a marine dinoflagellate, Scrippsiella hexapraecingula Horiguchi et Chihara, were investigated by thin sectioning and freeze-fracture electron microscopy. In one of these phases, the Motile phase, Cells have an outermost plasma membrane that is lined with flattened amphiesmal vesicles. Groups of microtubules lie beneath these vesicles. In mature Motile Cells, thecal plates are completely enclosed in individual amphiesmal vesicles. After settling, the Cells enter the second, non-Motile phase. Here, ecdysis occurs, resulting in several steps including formation of the first pellicle layer (PI), fusion of the inner amphiesmal vesicle membranes to form the new plasma membrane, deposition of the second pellicle layer (PM) under PI, and the appearance and fusion of juvenile amphiesmal vesicles to form new territories, which eventually give rise to new thecal plates in the next Motile phase. Thus, the pattern in which thecal plates are arranged in Motile Cells is determined at the time when the amphiesmal vesicles develop into non-Motile Cells.
Takeo Horiguchi - One of the best experts on this subject based on the ideXlab platform.
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P434-TH STEROLS FROM Motile Cells AND RESTING CYSTS OF AUTOTROPHIC AND HETEROTOROPHIC DINOFLAGELLATES
2015Co-Authors: Miki Amo, Noriyuki Suzuki, Hiroshi Kawamura, Aika Yamaguchi, Takeo HoriguchiAbstract:Dinoflagellate is one of the major primary producers in the ocean since the Mesozoic. These microalgae occur throughout the world’s oceans but are often more abundant in coastal areas. About half species of dinoflagellate are autotrophic ones, and others are heterotrophic. Some species are able to force themselves into a dormant or resting stage as part of their relatively complicated life cycle. These dormant stages, called resting cysts, are typically characterized by a thick and highly specialized cell covering. The Motile stage of dinoflagellate is difficult to be recorded in sediments since the Motile cell of dinoflagellate is labile against bio- and chemical degradation during the settling and the early diagenesis. The resting cysts of some dinoflagellates species are composed of resistant biomacromolecules, which can be preserved in sediments and sedimentary rocks. Geologic record of dinoflagellate evolution, therefore, is based on their resting cyst fossils in sedimentary rocks. The sterol compositions of dinoflagellates are generally dominated by 4-methyl sterols including the C30 sterol called dinosterol (4, 23, 24-trimethyl-5-cholest22E-en-3-ol). This sterol is rarely found in other algae and hence has been often used as an indicator of dinoflagellate contribution to the marine sediments. However, sedimentary dinosterols do no
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development of thecal plates and pellicle in the dinoflagellate scrippsiella hexapraecingula peridiniales dinophyceae elucidated by changes in stainability of the associated membranes
European Journal of Phycology, 2004Co-Authors: Satoko Sekida, Takeo Horiguchi, Kazuo OkudaAbstract:The development of the pellicle and thecal plates of the dinoflagellate Scrippsiella hexapraecingula Horiguchi et Chihara was investigated with particular emphasis on cellulose synthesis. In young Motile Cells, incipient thecal plates appear as several groups of granular material within individual sites that are thought to be amphiesmal vesicles and develop into thin, sheet-like plates. These plates subsequently thicken with the deposition of amorphous material and cellulose microfibrils to form mature thecal plates. After ecdysis, non-Motile Cells form a pellicle consisting of three layers, L1-3. L1 is electron dense, while L2 and L3 are electron transparent. L1 and L2 are non-cellulosic, but L3 contains cellulose microfibrils. A new type of putative cellulose-synthesizing enzyme complex was found in non-Motile Cells. It consists of two rows of particles occurring on the plasmatic fracture face of the plasma membrane and begins to appear 0.5 – 1 h after ecdysis. The periodic acid-thiocarbohydrazide-silve...
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development of the cell covering in the dinoflagellate scrippsiella hexapraecingula peridiniales dinophyceae
Phycological Research, 2001Co-Authors: Satoko Sekida, Takeo Horiguchi, Kazuo OkudaAbstract:SUMMARY The organization and development of cell coverings in two alternate phases of the life cycle in a marine dinoflagellate, Scrippsiella hexapraecingula Horiguchi et Chihara, were investigated by thin sectioning and freeze-fracture electron microscopy. In one of these phases, the Motile phase, Cells have an outermost plasma membrane that is lined with flattened amphiesmal vesicles. Groups of microtubules lie beneath these vesicles. In mature Motile Cells, thecal plates are completely enclosed in individual amphiesmal vesicles. After settling, the Cells enter the second, non-Motile phase. Here, ecdysis occurs, resulting in several steps including formation of the first pellicle layer (PI), fusion of the inner amphiesmal vesicle membranes to form the new plasma membrane, deposition of the second pellicle layer (PM) under PI, and the appearance and fusion of juvenile amphiesmal vesicles to form new territories, which eventually give rise to new thecal plates in the next Motile phase. Thus, the pattern in which thecal plates are arranged in Motile Cells is determined at the time when the amphiesmal vesicles develop into non-Motile Cells.
Litao Zhang - One of the best experts on this subject based on the ideXlab platform.
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the interrelation between photorespiration and astaxanthin accumulation in haematococcus pluvialis using metabolomic analysis
Algal Research-Biomass Biofuels and Bioproducts, 2019Co-Authors: Chunhui Zhang, Litao ZhangAbstract:Abstract To further investigate the interrelation between photorespiration and astaxanthin accumulation, metabolomic analysis of Haematococcus pluvialis during the astaxanthin accumulation period was performed, using gas chromatography–mass spectrometry (GC–MS), in the absence or presence of carboxymethoxylamine (CM), an inhibitor of the photorespiratory pathway. Algal samples were collected on days 0, 6 and 12, which were named as the green phase with green, non-Motile Cells, the brown phase with astaxanthin-synthesizing, non-Motile Cells, and the red phase with astaxanthin-enriched, red, non-Motile Cells, respectively. The inhibition of photorespiration by CM did not affect the biomass, had a slight effect on chlorophyll at the end of the incubation, but significantly suppressed astaxanthin accumulation. A total of 78 metabolites were identified by GC–MS, including 27 amino acids, 16 organic acids, 12 fatty acids, 7 polyols, 3 phosphoric acids, 3 sugars, 2 amines, and 8 other compounds. Multivariate statistical analyses (principal component analysis, partial least squares-discriminant analysis), and hierarchical cluster analysis revealed the clustering of the metabolites. Glycine and glycolic acid had accumulated substantially at both the brown and red phases, indicating that photorespiration was inhibited by CM. In presence of CM, the TCA cycle was restricted at the brown phase due to decreased intermediates, specifically, decreased levels of fructose and glucose. However, inhibiting photorespiration enhanced the levels of many intracellular cytoprotective metabolites, such as amino acids, polyamines, polyols and sucrose. A hypothetical metabolic regulation model of the photorespiratory pathway affecting astaxanthin accumulation of H. pluvialis is proposed. This study provides the first metabolomic evidence that photorespiration enhances astaxanthin accumulation.
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cell cycles and proliferation patterns in haematococcus pluvialis
Chinese Journal of Oceanology and Limnology, 2017Co-Authors: Chunhui Zhang, Jianguo Liu, Litao ZhangAbstract:Most studies on Haematococcus pluvialis have been focused on cell growth and astaxanthin accumulation; far less attention has been paid to cell cycles and proliferation patterns. The purpose of this study was to clarify cell cycles and proliferation patterns in H. pluvialis microscopically using a camera and video recorder system. The complicated life history of H. pluvialis can be divided into two stages: the Motile stage and the non-Motile stage. All the Cells can be classified into forms as follows: Motile cell, non-Motile cell, zoospore and aplanospore. The main cell proliferation, both in the Motile phase and non-Motile phase in H. pluvialis, is by asexual reproduction. Under normal growth conditions, a Motile cell usually produces two, sometimes four, and exceptionally eight zoospores. Under unfavorable conditions, the Motile cell loses its flagella and transforms into a non-Motile cell, and the non-Motile cell usually produces 2, 4 or 8 aplanospores, and occasionally 20–32 aplanospores, which further develop into non-Motile Cells. Under suitable conditions, the non-Motile cell is also able to release zoospores. The larger non-Motile Cells produce more than 16 zoospores, and the smaller ones produce 4 or 8 zoospores. Vegetative reproduction is by direct cell division in the Motile phase and by occasional cell budding in the non-Motile phase. There is, as yet, no convincing direct evidence for sexual reproduction.
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changes of photosynthetic behaviors and photoprotection during cell transformation and astaxanthin accumulation in haematococcus pluvialis grown outdoors in tubular photobioreactors
International Journal of Molecular Sciences, 2016Co-Authors: Litao Zhang, Chunhui Zhang, Fengying Gong, Jianguo LiuAbstract:The cell transformation from green Motile Cells to non-Motile Cells and astaxanthin accumulation can be induced in the green alga Haematococcus pluvialis cultured outdoors. In the initial 3 d of incubation (cell transformation phase), light absorption and photosynthetic electron transport became more efficient. After five days of incubation (astaxanthin accumulation phase), the light absorption per active reaction center (ABS/RC) increased, but the efficiency of electron transport (ψo) and the quantum yield of electron transport (φEo) decreased with increased time, indicating that the capacity of photosynthetic energy utilization decreased significantly during astaxanthin accumulation, leading to an imbalance between photosynthetic light absorption and energy utilization. It would inevitably aggravate photoinhibition under high light, e.g., at midday. However, the level of photoinhibition in H. pluvialis decreased as the incubation time increased, which is reflected by the fact that Fv/Fm determined at midday decreased significantly in the initial 3 d of incubation, but was affected very little after seven days of incubation, compared with that determined at predawn. This might be because the non-photochemical quenching, plastid terminal oxidase, photosystem I cyclic electron transport, defensive enzymes and the accumulated astaxanthin can protect Cells against photoinhibition.
Satoko Sekida - One of the best experts on this subject based on the ideXlab platform.
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development of thecal plates and pellicle in the dinoflagellate scrippsiella hexapraecingula peridiniales dinophyceae elucidated by changes in stainability of the associated membranes
European Journal of Phycology, 2004Co-Authors: Satoko Sekida, Takeo Horiguchi, Kazuo OkudaAbstract:The development of the pellicle and thecal plates of the dinoflagellate Scrippsiella hexapraecingula Horiguchi et Chihara was investigated with particular emphasis on cellulose synthesis. In young Motile Cells, incipient thecal plates appear as several groups of granular material within individual sites that are thought to be amphiesmal vesicles and develop into thin, sheet-like plates. These plates subsequently thicken with the deposition of amorphous material and cellulose microfibrils to form mature thecal plates. After ecdysis, non-Motile Cells form a pellicle consisting of three layers, L1-3. L1 is electron dense, while L2 and L3 are electron transparent. L1 and L2 are non-cellulosic, but L3 contains cellulose microfibrils. A new type of putative cellulose-synthesizing enzyme complex was found in non-Motile Cells. It consists of two rows of particles occurring on the plasmatic fracture face of the plasma membrane and begins to appear 0.5 – 1 h after ecdysis. The periodic acid-thiocarbohydrazide-silve...
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development of the cell covering in the dinoflagellate scrippsiella hexapraecingula peridiniales dinophyceae
Phycological Research, 2001Co-Authors: Satoko Sekida, Takeo Horiguchi, Kazuo OkudaAbstract:SUMMARY The organization and development of cell coverings in two alternate phases of the life cycle in a marine dinoflagellate, Scrippsiella hexapraecingula Horiguchi et Chihara, were investigated by thin sectioning and freeze-fracture electron microscopy. In one of these phases, the Motile phase, Cells have an outermost plasma membrane that is lined with flattened amphiesmal vesicles. Groups of microtubules lie beneath these vesicles. In mature Motile Cells, thecal plates are completely enclosed in individual amphiesmal vesicles. After settling, the Cells enter the second, non-Motile phase. Here, ecdysis occurs, resulting in several steps including formation of the first pellicle layer (PI), fusion of the inner amphiesmal vesicle membranes to form the new plasma membrane, deposition of the second pellicle layer (PM) under PI, and the appearance and fusion of juvenile amphiesmal vesicles to form new territories, which eventually give rise to new thecal plates in the next Motile phase. Thus, the pattern in which thecal plates are arranged in Motile Cells is determined at the time when the amphiesmal vesicles develop into non-Motile Cells.
Kenneth Neil Mertens - One of the best experts on this subject based on the ideXlab platform.
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cyst theca relationships of spiniferites bentorii s hyperacanthus s ramosus s scabratus and molecular phylogenetics of spiniferites and tectatodinium gonyaulacales dinophyceae
Phycologia, 2021Co-Authors: Kai Huo, Lourdes Morquecho, Vera Pospelova, Bernd Krock, Gwenael Bilien, Consuelo Carbonellmoore, živana Nincevic, Kenneth Neil MertensAbstract:It is well known that modern resting cysts with morphologies matching those of species of the fossil genus Spiniferites germinate into Motile Cells of the genus Gonyaulax. Different Spiniferites sp...