The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Hiroo Fukuda - One of the best experts on this subject based on the ideXlab platform.
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LOB DOMAIN-CONTAINING PROTEIN 15 Positively Regulates Expression of VND7, a Master Regulator of Tracheary Elements.
Plant & cell physiology, 2018Co-Authors: Kyoko Ohashi-ito, Kuninori Iwamoto, Hiroo FukudaAbstract:Xylem includes xylem parenchyma cells, fibers and Tracheary Elements. Differentiation of Tracheary Elements is an irreversible process that is controlled by the master regulator VASCULAR-RELATED NAC-DOMAIN 7 (VND7). Molecular events occurring downstream of VND7 are well understood, but little is known regarding upstream regulation of VND7. In this study, we identified LOB DOMAIN-CONTAINING PROTEIN 15 (LBD15)/ASYMMETRIC LEAVES2-LIKE (ASL11) as a regulator of VND7. LBD15 was expressed in immature vascular cells and positively regulated both VND7 expression and differentiation of Tracheary Elements. LBD15 directly associated with the upstream sequence of VND7 and positively regulated VND7 expression. A 25 bp upstream sequence was essential for VND7 expression in the elongation zone of Arabidopsis roots. Taken together with previous studies identifying LBD15 as a target of VND7, we propose that LBD15 acts in a positive feedback regulation system that promotes and accelerates VND7 expression during the initiation phase of Tracheary element differentiation in roots.
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ZEN1 is a key enzyme in the degradation of nuclear DNA during programmed cell death of Tracheary Elements
2015Co-Authors: Hiroo FukudaAbstract:Tracheary Elements (TEs) have a unique cell death program in which the rapid collapse of the vacuole triggers the be-ginning of nuclear degradation. Although various nucleases are known to function in nuclear DNA degradation in ani-mal apoptosis, it is unclear what hydrolase is involved in nuclear degradation in plants. In this study, we demonstrated that an S1-type nuclease, Zinnia endonuclease 1 (ZEN1), functions directly in nuclear DNA degradation during pro-grammed cell death (PCD) of TEs. In-gel DNase assay demonstrated the presence of a 24-kD Ca
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plant Tracheary Elements
eLS, 2010Co-Authors: Hiroo FukudaAbstract:The plant Tracheary element is the constituent of vessels and tracheids. Tracheary Elements are characterised by patterned secondary wall thickenings and programmed cell death (PCD) at maturity. Their differentiation is induced by plant hormones such as auxin, cytokinin and brassinosteroids, and suppressed by a small peptide, Tracheary element differentiation inhibitory factor (TDIF), secreted from phloem cells. The final determination of Tracheary element differentiation is initiated by master transcription factors, VAD6 and VND7 (vascular-related NAC-domain 7). The secondary wall pattern is formed by guiding the movement of cellulose synthase complex in the plasma membrane by the cortical microtubules. The PCD during Tracheary element differentiation is initiated by the rupture of the central vacuole in which cell death-related hydrolytic enzymes have been accumulated. Thus the process of Tracheary element differentiation is well understood, so that Tracheary element differentiation is an excellent model of cell differentiation in plants. Key Concepts: The xylem, which is tissue specific to the vascular plants, is composed of Tracheary Elements (TEs), parenchyma cells and fibres. Procambial cells produce the primary xylem containing protoxylem and metaxylem TEs in planta. Typical characteristics of TEs are patterned secondary wall thickenings and programmed cell death (PCD). TE differentiation is regulated by plant hormones such as auxin, cytokinin and brassinosteroids. A small peptide secreted from phloem cells prevents procambial cells from differentiating into TEs. VND6 and VND7 are master transcription factors that initiate TE differentiation. Microtubules determine the secondary wall pattern by guiding the movement of cellulose synthase complex in the plasma membrane. During the formation of secondary walls, levels of cellulose and hemicellulose increase and the deposition of pectin ceases, and a little later lignin deposition starts. The central vacuole plays a crucial role in TE PCD. A Zinnia xylogenic culture is an excellent model system of TE differentiation. Keywords: auxin; brassinosteroids; cell communication; cytokinin; master transcription factors; procambium; programmed cell death; secondary cell walls; xylem; Zinnia
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eLS - Plant Tracheary Elements
Encyclopedia of Life Sciences, 2010Co-Authors: Hiroo FukudaAbstract:The plant Tracheary element is the constituent of vessels and tracheids. Tracheary Elements are characterised by patterned secondary wall thickenings and programmed cell death (PCD) at maturity. Their differentiation is induced by plant hormones such as auxin, cytokinin and brassinosteroids, and suppressed by a small peptide, Tracheary element differentiation inhibitory factor (TDIF), secreted from phloem cells. The final determination of Tracheary element differentiation is initiated by master transcription factors, VAD6 and VND7 (vascular-related NAC-domain 7). The secondary wall pattern is formed by guiding the movement of cellulose synthase complex in the plasma membrane by the cortical microtubules. The PCD during Tracheary element differentiation is initiated by the rupture of the central vacuole in which cell death-related hydrolytic enzymes have been accumulated. Thus the process of Tracheary element differentiation is well understood, so that Tracheary element differentiation is an excellent model of cell differentiation in plants. Key Concepts: The xylem, which is tissue specific to the vascular plants, is composed of Tracheary Elements (TEs), parenchyma cells and fibres. Procambial cells produce the primary xylem containing protoxylem and metaxylem TEs in planta. Typical characteristics of TEs are patterned secondary wall thickenings and programmed cell death (PCD). TE differentiation is regulated by plant hormones such as auxin, cytokinin and brassinosteroids. A small peptide secreted from phloem cells prevents procambial cells from differentiating into TEs. VND6 and VND7 are master transcription factors that initiate TE differentiation. Microtubules determine the secondary wall pattern by guiding the movement of cellulose synthase complex in the plasma membrane. During the formation of secondary walls, levels of cellulose and hemicellulose increase and the deposition of pectin ceases, and a little later lignin deposition starts. The central vacuole plays a crucial role in TE PCD. A Zinnia xylogenic culture is an excellent model system of TE differentiation. Keywords: auxin; brassinosteroids; cell communication; cytokinin; master transcription factors; procambium; programmed cell death; secondary cell walls; xylem; Zinnia
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Inhibition of transdifferentiation into Tracheary Elements by polar auxin transport inhibitors through intracellular auxin depletion.
Plant and Cell Physiology, 2005Co-Authors: Saiko Yoshida, Hideo Kuriyama, Hiroo FukudaAbstract:Polar auxin transport is essential for the formation of continuous vascular strands in the plant body. To understand its mechanism, polar auxin transport inhibitors have often been used. However, the role of auxin in vascular differentiation at the unicellular level has remained elusive. Using a Zinnia elegans cell culture system, in which single mesophyll cells transdifferentiate into Tracheary Elements (TEs), we demonstrated that auxin transport inhibitors prevented TE differentiation and that high concentrations of 1-naphthaleneacetic acid (NAA) and IAA overcame the repression of TE differentiation. Measurements of NAA accumulation with 3H-labeled NAA in the presence or absence of 1-N-naphthylphthalamic acid (NPA) revealed enhanced NAA accumulation within the cell. In the NPA-treated cells, intracellular free NAA decreased, while its metabolites increased. Therefore, the polar auxin transport inhibitors may prevent auxin efflux and consequently promote NAA accumulation in Zinnia cells. The excess intracellular NAA may also activate NAA metabolism, resulting in a decrease in free NAA levels. This depletion of free NAA may prevent TE differentiation. The decreased auxin activity in NPA-treated cells was confirmed by the fact that the DR5 (a synthetic auxin-inducible promoter)-mediated expression of a reporter protein was suppressed in such cells. Gene expression analysis indicated that NPA suppressed TE differentiation at an early process of transdifferentiation into TEs. Based on these results, the inter-relationship between auxin and vascular cell development at a cellular level is discussed.
Atsushi Komamine - One of the best experts on this subject based on the ideXlab platform.
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Short Communication Effect of Inhibitors of ADP-ribosyltransferase on the Differentiation of Tracheary Elements
2016Co-Authors: Munetaka Sugiyama, Atsushi KomamineAbstract:The effect of m-aminobenzamide (m-ABm) and nicotinamide, inhibitors of ADP-ribosyltransferase (ADP-RT), on the differentiation of Tracheary Elements was investigated using isolated mesophyll cells of Zinnia elegans. Both compounds inhibited differentiation without affecting cell division, a result which suggests the involvement of ADP-RT. The effects of thymidine, a potent inhibitor of ADP-RT and isomers of m-ABm were also examined. Key words: ADP-ribosyltransferase — Aminobenzamide — Cytodifferentiation — Nicotinamide — Tracheary element — Zinnia elegans. ADP-RT catalyzes the transfer of ADP-ribose from NAD+ to chromatin-bound proteins, and this enzyme has been proposed as a regulator of DNA metabolism via poly(ADP-ribosyl)ation of nuclear enzymes (Purnell et al. 1980). m-ABm and nicotinamide, inhibitors of ADP-RT, have been reported to inhibit cytodifferentiation in some vertebrate cells (Farzaneh et al. 1982, Althaus et al. 1982a, Johnstone and Williams 1982). The function of ADP-RT in cytodifferentiation is thought to be related to the breakage and rejoining of DNA strands because of the involvement of ADP-RT in DNA excision repair (Durkacz et al. 1980, Creissen and Shal
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Short Communication Suppression by 5-Bromo-2-deoxyuridine of Transdifferentiation into Tracheary Elements of Isolated Mesophyll Cells of Zinnia elegans
2016Co-Authors: Yuichi Shoji, Munetaka Sugiyama, Atsushi KomamineAbstract:suppressed the transdifferentiation into Tracheary Elements (TE) of isolated mesophyll cells of Zinnia elegans without affecting cell division. Tracer experiments with [3H]BrdU indicated that 76 % and 24 % of the incorporated radioac-tivity was located in the DNA and the RNA, respective-ly. Both thymidine and uridine counteracted the inhibitory effect of BrdU on transdifferentiation but thymidine was much more effective than uridine. These results suggest that BrdU might interfere with transdifferentiation via its incorporation into DNA. The timing of effective suppres-sion by BrdU was examined by monitoring the effects of the sequential addition of BrdU and thymidine with an in-terval of 12 h at various times in culture. Transdifferentia-tion was most sensitive to BrdU between the 24th and the 36th hour of culture. This result suggests that this window of time is critical for DNA synthesis during the transdiffer-entiation of isolated mesophyll cells of Zinnia elegans into TE
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Involvement of Poly(ADP-Ribose) Synthesis in Transdifferentiation of Isolated Mesophyll Cells of Zinnia elegans into Tracheary Elements
Plant and Cell Physiology, 1997Co-Authors: Yuichi Shoji, Munetaka Sugiyama, Atsushi KomamineAbstract:The relationship between poly(ADP-ribose) synthesis and cytodifferentiation was studied in the well characterized Zinnia system, in which isolated mesophyll cells of Zinnia elegans transdifferentiate into Tracheary Elements (TE) in a suspension culture in the presence of both auxin and cytokinin. The rate of poiy(ADP-ribose) synthesis was measured in nuclei isolated from cells that had been induced to undergo transdifferentiation, and activation of such synthesis was observed before the appearance of TE during culture. In cultures without auxin or cytokinin, poly(ADP-ribose) synthesis appeared to proceed much more slowly. Treatment of cells with a potent inhibitor of poly(ADP-ribose) polymerase, namely, 6(5H)-phenanthridinone (PT), resulted in the blockage of TE formation and a decrease in the frequency of cell division. PT was very effective in interfering with transdifferentiation, in particular, when supplied between the 24th hour and the 36th hour of culture. Repair-type DNA synthesis, which has been proposed to participate in transdifferentiation, was suppressed by the treatment with PT. These results suggest that poIy(ADP-ribose) synthesis and subsequent repairtype DNA synthesis might play a critical role in the transdifferentiation of Zinnia cells.
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Suppression by 5-Bromo-2'-deoxyuridine of Transdifferentiation into Tracheary Elements of Isolated Mesophyll Cells of Zinnia elegans
Plant and Cell Physiology, 1996Co-Authors: Yuichi Shoji, Munetaka Sugiyama, Atsushi KomamineAbstract:5-Bromo-2'-deoxyuridine (BrdU), a thymidine analog, suppressed the transdifferentiation into Tracheary Elements (TE) of isolated mesophyll cells of Zinnia elegans without affecting cell division. Tracer experiments with [3H]BrdU indicated that 76% and 24% of the incorporated radioactivity was located in the DNA and the RNA, respectively. Both thymidine and uridine counteracted the inhibitory effect of BrdU on transdifferen tiation but thymidine was much more effective than uridine. These results suggest that BrdU might interfere with transdifferentiation via its incorporation into DNA. The timing of effective suppression by BrdU was examined by monitoring the effects of the sequential addition of BrdU and thymidine with an interval of 12 h at various times in culture. Transdifferentiation was most sensitive to BrdU between the 24th and the 36th hour of culture. This result suggests that this window of time is critical for DNA synthesis during the transdifferentiation of isolated mesophyll cells of Zinnia elegans into TE.
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possible involvement of dna repair events in the transdifferentiation of mesophyll cells of zinnia elegans into Tracheary Elements
Journal of Plant Research, 1995Co-Authors: Munetaka Sugiyama, Edward C Yeung, Yuichi Shoji, Atsushi KomamineAbstract:In cultures of isolated mesophyll cells ofZinnia elegans, transdifferentiation into Tracheary Elements is induced by a combination of auxin and cytokinin and is blocked by inhibitors of DNA synthesis and poly (ADP-ribose) synthesis. During transdifferentiation, a very low level of synthesis of nuclear DNA was found in some cultured cells by microautoradiography after pulse-labeling with [3H]thymidine. Density profiles of nuclear DNA that had been double-labeledin vivo with bromodeoxyuridine (BrdU) and [3H]thymidine indicated that this DNA synthesis was repair-type synthesis. The sedimentation velocity of nucleoids increased during the culture of isolated mesophyll cells and the increase was dependent on phytohormones. This phenomenon may reflect the rejoining of DNA strand breaks after repair-type DNA synthesis during transdifferentiation. Treatment of cells with inhibitors of DNA synthesis or of poly(ADP-ribose) synthesis prevented the increase in the sedimentation velocity of nucleoids. The data suggest the involvement of DNA-repair events in the transdifferentiation of mesophyll cells into Tracheary Elements.
Steven Jansen - One of the best experts on this subject based on the ideXlab platform.
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Anatomical features associated with water transport in imperforate Tracheary Elements of vessel-bearing angiosperms
Annals of botany, 2011Co-Authors: Yuzou Sano, Hugh Morris, Hiroshi Shimada, Louis P. Ronse De Craene, Steven JansenAbstract:† Background and Aims Imperforate Tracheary Elements (ITEs) in wood of vessel-bearing angiosperms may or may not transport water. Despite the significance of hydraulic transport for defining ITE types, the combination of cell structure with water transport visualization in planta has received little attention. This study provides a quantitative analysis of structural features associated with the conductive vs. non-conductive nature of ITEs. † Methods Visualization of water transport was studied in 15 angiosperm species by dye injection and cryo-scanning electron microscopy. Structural features of ITEs were examined using light and electron microscopy. † Key Results ITEs connected to each other by pit pairs with complete pit membranes contributed to water transport, while cells showing pit membranes with perforations up to 2 mm were hydraulically not functional. A close relationship was found between pit diameter and pit density, with both characters significantly higher in conductive than in non-conductive cells. In species with both conductive and non-conductive ITEs, a larger diameter was characteristic of the conductive cells. Water transport showed no apparent relationship with the length of ITEs and vessel grouping. † Conclusions The structure and density of pits between ITEs represent the main anatomical characters determining water transport. The pit membrane structure of ITEs provides a reliable, but practically challenging, criterion to determine their conductive status. It is suggested that the term tracheids should strictly be used for conductive ITEs, while fibre-tracheids and libriform fibres are non-conductive.
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The Distribution and Structure of Pits Between Vessels and Imperforate Tracheary Elements in Angiosperm Woods
IAWA Journal, 2008Co-Authors: Yuzou Sano, Tomohiro Ohta, Steven JansenAbstract:This study focuses on the interspecific variation in the distribution and structure of pits between vessels and imperforate Tracheary Elements. Specimens from the outer sapwood of eight species, in which vessel Elements are frequently in contact with fibres and/or tracheids, were prepared using two different techniques and examined by field-emission scanning electron microscopy. In three species in which vessels are surrounded by vasicentric tracheids and/or fibres with distinctly bordered pits, pit pairs frequently occurred in walls between vessels and imperforate Tracheary Elements. In the five species in which vessels are in contact with fibres with indistinctly bordered pits, no or very few pit pairs were present, and blind pits were often found. Blind pits were exclusively present in vessel Elements in some species, while they were restricted to imperforate Tracheary Elements in other species. The nature of vessel to imperforate Tracheary element pitting appears to depend on Tracheary element specialization.
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Pit membranes in Tracheary Elements of Rosaceae and related families: New records of tori and pseudotori
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Steven Jansen, David Rabaey, Frederic Lens, Yuzou Sano, Brendan Choat, Roland R. DuteAbstract:The micromorphology of pits in Tracheary Elements was examined in 35 species representing 29 genera of Rosaceae and related families to evaluate the assumption that angiosperm pits are largely invariant. In most Rosaceae, pit membranes between fibers and tracheids frequently appear to have amorphous thickenings with an irregular distribution. Although these structures are toruslike under the light microscope, observations by electron microscopy illustrate that they represent ‘‘pseudotori’’ or plasmodesmata-associated thickenings. These thickenings frequently extend from the periphery of the pit membrane and form a cap-like, hollow structure. Pseudotori are occasionally found in few Elaeagnaceae and Rhamnaceae and appear to be related to species with fiber-tracheids and/or tracheids. True tori are strongly associated with round to oval pit
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Pit membranes in Tracheary Elements of Rosaceae and related families: New records of tori and pseudotori
Various articles, 2007Co-Authors: Steven Jansen, David Rabaey, Yuzou Sano, Brendan Choat, Frederic LensAbstract:The micromorphology of pits in Tracheary Elements was examined in 35 species representing 29 genera of Rosaceae and related families to evaluate the assumption that angiosperm pits are largely invariant. In most Rosaceae, pit membranes between fibers and tracheids frequently appear to have amorphous thickenings with an irregular distribution. Although these structures are toruslike under the light microscope, observations by electron microscopy illustrate that they represent ‘‘pseudotori’’ or plasmodesmata-associated thickenings. These thickenings frequently extend from the periphery of the pit membrane and form a cap-like, hollow structure. Pseudotori are occasionally found in few Elaeagnaceae and Rhamnaceae and appear to be related to species with fiber-tracheids and/or tracheids. True tori are strongly associated with round to oval pit apertures and are consistently present in narrow Tracheary Elements of Cercocarpus (Rosaceae), Planera (Ulmaceae), and ring-porous species of Ulmus and Zelkova (Ulmaceae). Vestured pits with homogenous pit membranes are reported for Hemiptelea (Ulmaceae). The homoplasticnature of pit membrane characteristics may be related to functional adaptations in terms of safety and efficiency of water transportor may reflect different developmental processes of xylem Elements. These observations illustrate that there is more variation in angiosperm pits than previously thought.
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The micromorphology of pit membranes in Tracheary Elements of ericales: new records of tori or pseudo-tori?
Annals of Botany, 2006Co-Authors: David Rabaey, Frederic Lens, Erik Smets, Steven JansenAbstract:Background and Aims Intervascular pit membranes were examined within Ericales to determine the distribution and structure of torus-like thickenings. Methods Forty-nine species representing 12 families of the order Ericales were investigated using light, scanning and transmission electron microscopy. They were compared with four species of Oleaceae to determine the true nature of the thickenings. Key Results Pit membranes with torus-like thickenings were observed in seven species of Ericaceae and were found to be amorphous, plasmodesmata-associated structures with an irregular distribution. These pseudo-tori show major differences compared with true tori with respect to their distribution and ultrastructure. Genuine tori, which are strongly correlated with round pit apertures in narrow Tracheary Elements, were found in two species of Osmanthus (Oleaceae). Conclusions The pseudo-tori found in some Ericaceae are considered to be similar to pit membrane thickenings previously recorded in Rosaceae. While true tori appear to be functionally significant in terms of efficiency and safety of water transport, the possible function of pseudo-tori could be associated with the role of plasmodesmata during differentiation of tracheids, fibre-tracheids or narrow vessels.
Munetaka Sugiyama - One of the best experts on this subject based on the ideXlab platform.
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Short Communication Effect of Inhibitors of ADP-ribosyltransferase on the Differentiation of Tracheary Elements
2016Co-Authors: Munetaka Sugiyama, Atsushi KomamineAbstract:The effect of m-aminobenzamide (m-ABm) and nicotinamide, inhibitors of ADP-ribosyltransferase (ADP-RT), on the differentiation of Tracheary Elements was investigated using isolated mesophyll cells of Zinnia elegans. Both compounds inhibited differentiation without affecting cell division, a result which suggests the involvement of ADP-RT. The effects of thymidine, a potent inhibitor of ADP-RT and isomers of m-ABm were also examined. Key words: ADP-ribosyltransferase — Aminobenzamide — Cytodifferentiation — Nicotinamide — Tracheary element — Zinnia elegans. ADP-RT catalyzes the transfer of ADP-ribose from NAD+ to chromatin-bound proteins, and this enzyme has been proposed as a regulator of DNA metabolism via poly(ADP-ribosyl)ation of nuclear enzymes (Purnell et al. 1980). m-ABm and nicotinamide, inhibitors of ADP-RT, have been reported to inhibit cytodifferentiation in some vertebrate cells (Farzaneh et al. 1982, Althaus et al. 1982a, Johnstone and Williams 1982). The function of ADP-RT in cytodifferentiation is thought to be related to the breakage and rejoining of DNA strands because of the involvement of ADP-RT in DNA excision repair (Durkacz et al. 1980, Creissen and Shal
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Short Communication Suppression by 5-Bromo-2-deoxyuridine of Transdifferentiation into Tracheary Elements of Isolated Mesophyll Cells of Zinnia elegans
2016Co-Authors: Yuichi Shoji, Munetaka Sugiyama, Atsushi KomamineAbstract:suppressed the transdifferentiation into Tracheary Elements (TE) of isolated mesophyll cells of Zinnia elegans without affecting cell division. Tracer experiments with [3H]BrdU indicated that 76 % and 24 % of the incorporated radioac-tivity was located in the DNA and the RNA, respective-ly. Both thymidine and uridine counteracted the inhibitory effect of BrdU on transdifferentiation but thymidine was much more effective than uridine. These results suggest that BrdU might interfere with transdifferentiation via its incorporation into DNA. The timing of effective suppres-sion by BrdU was examined by monitoring the effects of the sequential addition of BrdU and thymidine with an in-terval of 12 h at various times in culture. Transdifferentia-tion was most sensitive to BrdU between the 24th and the 36th hour of culture. This result suggests that this window of time is critical for DNA synthesis during the transdiffer-entiation of isolated mesophyll cells of Zinnia elegans into TE
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activity of cell wall degradation associated with differentiation of isolated mesophyll cells of zinnia elegans into Tracheary Elements
Planta, 2002Co-Authors: Youichi Ohdaira, Munetaka Sugiyama, Koichi Kakegawa, Shinichi Amino, Hiroo FukudaAbstract:Cell walls were prepared from cultured mesophyll cells of Zinnia elegans L. that were transdifferentiating into Tracheary Elements and incubated in a buffer to undergo autolysis. The rate of autolysis of cell walls was determined by measuring the amount of carbohydrate released from the cell walls into the buffer during incubation. During the course of culture of mesophyll cells, the autolysis rate increased markedly at the time when thickenings of secondary cell walls characteristic of Tracheary Elements became visible (after 48-72 h of culture), and thereafter the rate remained at a high level. Comparative studies on the autolysis rate of cell walls using various control cultures, in which Tracheary element differentiation did not take place, revealed a close relationship between the autolysis rate around the 60th hour of culture and differentiation. Sugar analysis by colorimetric assays and gas chromatography of carbohydrates released from the cell walls detected uronic acid, arabinose, galactose, glucose, xylose, rhamnose, fucose, and mannose. Among these sugars, uronic acid was the most abundant, and accounted for approximately half of the total released sugars. The decrease of acidic polysaccharides in the primary cell walls during Tracheary element differentiation was visualized by staining cultured cells with alcian blue at pH 2.5. These results suggest that active degradation of components of primary cell walls, including pectin, is integrated into the program of Tracheary element differentiation.
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Involvement of Poly(ADP-Ribose) Synthesis in Transdifferentiation of Isolated Mesophyll Cells of Zinnia elegans into Tracheary Elements
Plant and Cell Physiology, 1997Co-Authors: Yuichi Shoji, Munetaka Sugiyama, Atsushi KomamineAbstract:The relationship between poly(ADP-ribose) synthesis and cytodifferentiation was studied in the well characterized Zinnia system, in which isolated mesophyll cells of Zinnia elegans transdifferentiate into Tracheary Elements (TE) in a suspension culture in the presence of both auxin and cytokinin. The rate of poiy(ADP-ribose) synthesis was measured in nuclei isolated from cells that had been induced to undergo transdifferentiation, and activation of such synthesis was observed before the appearance of TE during culture. In cultures without auxin or cytokinin, poly(ADP-ribose) synthesis appeared to proceed much more slowly. Treatment of cells with a potent inhibitor of poly(ADP-ribose) polymerase, namely, 6(5H)-phenanthridinone (PT), resulted in the blockage of TE formation and a decrease in the frequency of cell division. PT was very effective in interfering with transdifferentiation, in particular, when supplied between the 24th hour and the 36th hour of culture. Repair-type DNA synthesis, which has been proposed to participate in transdifferentiation, was suppressed by the treatment with PT. These results suggest that poIy(ADP-ribose) synthesis and subsequent repairtype DNA synthesis might play a critical role in the transdifferentiation of Zinnia cells.
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Suppression by 5-Bromo-2'-deoxyuridine of Transdifferentiation into Tracheary Elements of Isolated Mesophyll Cells of Zinnia elegans
Plant and Cell Physiology, 1996Co-Authors: Yuichi Shoji, Munetaka Sugiyama, Atsushi KomamineAbstract:5-Bromo-2'-deoxyuridine (BrdU), a thymidine analog, suppressed the transdifferentiation into Tracheary Elements (TE) of isolated mesophyll cells of Zinnia elegans without affecting cell division. Tracer experiments with [3H]BrdU indicated that 76% and 24% of the incorporated radioactivity was located in the DNA and the RNA, respectively. Both thymidine and uridine counteracted the inhibitory effect of BrdU on transdifferen tiation but thymidine was much more effective than uridine. These results suggest that BrdU might interfere with transdifferentiation via its incorporation into DNA. The timing of effective suppression by BrdU was examined by monitoring the effects of the sequential addition of BrdU and thymidine with an interval of 12 h at various times in culture. Transdifferentiation was most sensitive to BrdU between the 24th and the 36th hour of culture. This result suggests that this window of time is critical for DNA synthesis during the transdifferentiation of isolated mesophyll cells of Zinnia elegans into TE.
Ryo Funada - One of the best experts on this subject based on the ideXlab platform.
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Tracheary Elements from calli of Japanese horse chestnut (Aesculus turbinata) form perforation-like structures.
Planta, 2021Co-Authors: Yusuke Yamagishi, Joto Yoshimoto, Satoshi Nakaba, Eri Nabeshima, Ugai Watanabe, Kayo Kudo, Ryo FunadaAbstract:MAIN CONCLUSION Calli derived from young leaves of Aesculus turbinata contained Tracheary Elements with large pores that resembled perforations of vessel Elements. The differentiation of Tracheary Elements in vitro provides a useful system for detailed analysis of xylem cell differentiation. To examine the mechanism of formation of cell wall structures, new differentiation systems are required that allows us to induce highly organized structures, such as perforations. In this study, we developed such a system in which we were able to induce formation of Tracheary Elements with perforations, using calli of a hardwood, Aesculus turbinata. Young leaves of A. turbinata were placed on modified MS medium that contained 5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 5 μM benzyladenine (BA). Tracheary Elements were induced in calli derived from young leaves of A. turbinata. Some Tracheary Elements formed broad areas of secondary wall with typical features of secondary xylem. Other Tracheary Elements formed spiral thickenings, which are typical features of vessel Elements in secondary xylem of A. turbinata. Approximately 10% of Tracheary Elements formed large pores that resembled perforations of vessel Elements and various types of the perforation plate were observed. Addition of NAA and brassinolide to the induction medium enhanced the differentiation of Tracheary Elements in calli of A. turbinata. Newly induced Tracheary Elements also formed typical features of secondary xylem such as perforations of the vessel Elements. Our model system might be useful in efforts to understand the mechanisms of formation of highly organized structures in Tracheary Elements in secondary xylem.
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partial desiccation enhances induction of secondary xylem like Tracheary Elements from calli of hybrid poplar populus sieboldii x p grandidentata
Trees-structure and Function, 2017Co-Authors: Yusuke Yamagishi, Joto Yoshimoto, Satoshi Nakaba, Ryo Funada, Eri Nabeshima, Ugai Watanabe, Suzuka IdeAbstract:Key message Calli of hybrid poplar that had been exposed to desiccation in air before transfer to the induction medium differentiated into Tracheary Elements at higher rates than calli without air desiccation.
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In vitro induction of the formation of Tracheary Elements from suspension-cultured cells of the conifer Cryptomeria japonica
Trees, 2015Co-Authors: Yusuke Yamagishi, Takenao Sato, Hiromu Uchiyama, Joto Yoshimoto, Satoshi Nakaba, Ugai Watanabe, Kei Kitamura, Ryo FunadaAbstract:Key message We found Tracheary Elements that were induced in suspension cultures of cells derived from young needles of the coniferCryptomeria japonica after cells had been transferred to solidified medium.
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In vitro induction of secondary xylem-like Tracheary Elements in calli of hybrid poplar ( Populus sieboldii × P. grandidentata )
Planta, 2013Co-Authors: Yusuke Yamagishi, Hiromu Uchiyama, Joto Yoshimoto, Satoshi Nakaba, Eri Nabeshima, Ugai Watanabe, Ryo FunadaAbstract:The formation of Tracheary Elements was induced in calli derived from petioles of hybrid poplar (Populus sieboldii × P. grandidentata) after 10 days of culture on medium that lacked auxin but contained 1 μM brassinolide. Some differentiated cells formed broad regions of cell walls and bordered pits, which are typical features of Tracheary Elements of secondary xylem. Other differentiated cells resembled Tracheary Elements of primary xylem, with spiral or reticulate thickening of cell walls. The Tracheary Elements that developed in calli were formed within cell clusters. This induction system provides a new model for studies of the mechanism of differentiation of secondary xylem cells in vitro.
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in vitro induction of secondary xylem like Tracheary Elements in calli of hybrid poplar populus sieboldii p grandidentata
Planta, 2013Co-Authors: Yusuke Yamagishi, Hiromu Uchiyama, Joto Yoshimoto, Satoshi Nakaba, Eri Nabeshima, Ugai Watanabe, Ryo FunadaAbstract:The formation of Tracheary Elements was induced in calli derived from petioles of hybrid poplar (Populus sieboldii × P. grandidentata) after 10 days of culture on medium that lacked auxin but contained 1 μM brassinolide. Some differentiated cells formed broad regions of cell walls and bordered pits, which are typical features of Tracheary Elements of secondary xylem. Other differentiated cells resembled Tracheary Elements of primary xylem, with spiral or reticulate thickening of cell walls. The Tracheary Elements that developed in calli were formed within cell clusters. This induction system provides a new model for studies of the mechanism of differentiation of secondary xylem cells in vitro.
