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Teruo Shimmen - One of the best experts on this subject based on the ideXlab platform.
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Transduction of pressure signal to electrical signal upon sudden increase in turgor pressure in Chara corallina
Journal of Plant Research, 2013Co-Authors: Teruo Shimmen, Koreaki OgataAbstract:By taking advantage of large cell size of Chara corallina , we analyzed the membrane depolarization induced by decreased turgor pressure (Shimmen in J Plant Res 124:639–644, 2011 ). In the present study, the response to increased turgor pressure was analyzed. When internodes were incubated in media containing 200 mM dimethyl sulfoxide, their intracellular osmolality gradually increased and reached a steady level after about 3 h. Upon removal of dimethyl sulfoxide, turgor pressure quickly increased. In response to the increase in turgor pressure, the internodes generated a transient membrane depolarization at its nodal end. The refractory period was very long and it took about 2 h for full recovery after the depolarizing response. Involvement of protein synthesis in recovery from refractoriness was suggested, based on experiments using inhibitors.
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Involvement of protein synthesis in recovery from refractory period of electrical depolarization induced by osmotic stimulation in Chara corallina
Journal of Plant Research, 2011Co-Authors: Teruo ShimmenAbstract:Upon addition of sorbitol to the external medium of an internodal cell of Chara corallina , a transient depolarization is induced at its nodal end (Shimmen in Plant Cell Physiol 44:1215–1224, 2003 ). In the present study, refractory period was found to be very long, 2–4 h. Recovery from refractoriness was completely inhibited by inhibitors of eukaryote-type protein synthesis, cycloheximide or anisomysin, but not by inhibitors of prokaryote-type protein synthesis. This suggested that proteinous factor(s) responsible for generation of the depolarization is lost or inactivated upon depolarization and synthesized during the resting state. Low temperature, which is supposed to inhibit protein synthesis, also inhibited recovery from refractoriness. When unstimulated internodal cells were incubated in the medium containing an inhibitor of eukaryote-type protein synthesis, generation of the depolarization was almost completely inhibited. This result suggested that the factor is slowly turning over even in the absence of osmotic stimulation.
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Involvement of membrane potential in alkaline band formation by internodal cells of Chara corallina.
Plant & cell physiology, 2008Co-Authors: Teruo Shimmen, Akiko WakabayashiAbstract:Internodal cells of Chara corallina form alkaline bands on their surface upon illumination via photosynthesis. In the present study, the effect of KCl on alkaline band formation was analyzed. When the extracellular KCl concentration was increased, alkaline band formation was extensively inhibited. Electrophysiological analysis unequivocally showed the need for inner negative membrane potential for alkaline band formation.
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Electrophysiological Characterization of the Node in Chara corallina: Functional Differentiation for Wounding Response
Plant & cell physiology, 2008Co-Authors: Teruo ShimmenAbstract:Electrical Characteristics of the node were analyzed in comparison with those of the flank of the internodal cell in Chara corallina. The dependence of the membrane potential of the node on pH and K + concentration was almost the same as that of the flank. In the flank, the increase in the Ca 2 + concentration stopped the depolarization in the presence of 100 mM KCl. In the node, however, Ca 2 + could not stop the depolarization induced by 100 mM KCl. It has been reported that the node has a function to tranduce the signal of osmotic shock into a transient depolarization. In combination with osmotic shock, 10 mM K + could induce a long-lasting depolarization of the node. These electrical Characteristics of the node were suggested to be responsible for the electrical response to wounding in Characeae.
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Studies on Alkaline Band Formation in Chara corallina: Ameliorating Effect of Ca2+ on Inhibition Induced by Osmotic Shock
Plant & cell physiology, 2003Co-Authors: Teruo Shimmen, Satoko Yonemura, Mio Negoro, William J. LucasAbstract:;Although the decrease in cell turgor by application of sorbitol to the external medium did not inhibit the alkaline band formation in Chara corallina, recovery of normal turgor severely inhibited it. Alkaline-loading analysis suggested that the inhibition of alkaline band formation was caused by inhibition of HCO3 – influx but not that of OH – efflux. In the presence of 10 mM CaCl2, the capacity of alkaline band formation was maintained during osmotic treatment. Cells could not form alkaline bands, when plasmolysis was induced by application of sorbitol at a higher concentration. Addition of 10 mM CaCl2 could ameliorate the inhibition caused by plasmolyis.
John S. Boyer - One of the best experts on this subject based on the ideXlab platform.
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Tension required for pectate chemistry to control growth in Chara corallina
Journal of Experimental Botany, 2007Co-Authors: Timothy E. Proseus, John S. BoyerAbstract:Recent work showed that polygalacturonate (pectate) chemistry controlled the growth rate of the large-celled alga Chara corallina when turgor pressure (P) was normal (about 0.5 MPa). The mechanism involved calcium withdrawal from the wall by newly supplied pectate acting as a chelator. But P itself can affect growth rate. Therefore, pectate chemistry was investigated at various P. A pressure probe varied P in isolated walls, varying the tension on the calcium pectate cross-links bearing the load of P. When soluble pectate was newly supplied, the wall grew irreversibly but the pectate was inactive below a P of 0.2 MPa, indicating that tension was required in the existing wall before new pectate acted. It was suggested that the tension distorted some of the wall pectate (the dominant pectin), weakening its calcium cross-links and causing the calcium to be preferentially lost to the new pectate, which was not distorted. The preferential loss provided a molecular mechanism for loosening the wall structure, resulting in faster growth. However, the resulting relaxation of the vacated wall pectate would cause calcium to be exchanged with load-bearing calcium pectate nearby, auto-propagating throughout the wall for long periods. There is evidence for this effect in isolated walls. In live cells, there is also evidence that auto-propagation is controlled by binding the newly supplied pectate (now calcium pectate) to the wall and/or by additional Ca(2+) entering the wall structure. A tension-dependent cycle of pectate chemistry thus appeared to control growth while new wall was deposited as a consequence.
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calcium pectate chemistry controls growth rate of Chara corallina
Journal of Experimental Botany, 2006Co-Authors: Timothy E. Proseus, John S. BoyerAbstract:Pectin, a normal constituent of cell walls, caused growth rates to accelerate to the rates in living cells when supplied externally to isolated cell walls of Chara corallina. Because this activity was not reported previously, the activity was investigated. Turgor pressure (P) was maintained in isolated walls or living cells using a pressure probe in culture medium. Pectin from various sources was supplied to the medium. Ca and Mg were the dominant inorganic elements in the wall. EGTA or pectin in the culture medium extracted moderate amounts of wall Ca and essentially all the wall Mg, and wall growth accelerated. Removing the external EGTA or pectin and replacing with fresh medium returned growth to the original rate. A high concentration of Ca 2+ quenched the accelerating activity of EGTA or pectin and caused gelling of the pectin, physically inhibiting wall growth. Low pH had little effect. After the Mg had been removed, Ca-pectate in the wall bore the longitudinal load imposed by P. Removal of this Ca caused the wall to burst. Live cells and isolated walls reacted similarly. It was concluded that Ca cross-links between neighbouring pectin molecules were strong wall bonds that controlled wall growth rates. The central role of Ca-pectate chemistry was illustrated by removing Ca cross-links with new pectin (wall 'loosening'), replacing vacated cross-links with new Ca 2+ ('Ca 2+ -tightening'), or adding new cross-links with new Ca-pectate that gelled ('gel tightening'). These findings establish a molecular model for growth that includes wall deposition and assembly for sustained growth activity.
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Identifying cytoplasmic input to the cell wall of growing Chara corallina
Journal of experimental botany, 2006Co-Authors: Timothy E. Proseus, John S. BoyerAbstract:Plants enlarge mostly because the walls of certain cells enlarge, with accompanying input of wall constituents and other factors from the cytoplasm. However, the enlargement can occur without input, suggesting an uncertain relationship between cytoplasmic input and plant growth. Therefore, the role of the input was investigated by quantitatively comparing growth in isolated walls (no input) with that in living cells (input occurring). Cell walls were isolated from growing internodes of Chara corallina and filled with pressurized oil to control turgor pressure while elongation was monitored. Turgor pressure in living cells was similarly controlled and monitored by adding/removing cell solution. Temperature was varied in some experiments. At all pressures and temperatures, isolated walls displayed turgor-driven growth indistinguishable in every respect from that in living cells, except the rate decelerated in the isolated walls while the living cells grew rapidly. The growth in the isolated walls was highly responsive to temperature, in contrast to the elastic extension that has been shown to be insensitive to similar temperatures. Consequently, strong intermolecular bonds were responsible for growth and weak bonds for elastic extension. Boiling the walls gave the same results, indicating that enzyme activities were not controlling these bonds. However, pectin added to isolated walls reversed their growth deceleration and returned the rate to that in the living cells. The pectin was similar to that normally produced by the cytoplasm and deposited in the wall, suggesting that continued cytoplasmic input of pectin may play a role in sustaining turgor-driven growth in Chara.
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Identifying cytoplasmic input to the cell wall of growing Chara corallina
2006Co-Authors: Timothy E. Proseus, John S. BoyerAbstract:Plants enlarge mostly because the walls of certain cells enlarge, with accompanying input of wall constituents and other factors from the cytoplasm. However, the enlargement can occur without input, suggesting an uncertain relationship between cytoplasmic input and plant growth. Therefore, the role of the input was investigated by quantitatively comparing growth in isolated walls (no input) with that in living cells (input occurring). Cell walls were isolated from growing internodes of Chara corallina and filled with pressur-ized oil to control turgor pressure while elongation wasmonitored. Turgor pressure in living cells was simi-larly controlled and monitored by adding/removing cell solution. Temperature was varied in some experi-ments. At all pressures and temperatures, isolated walls displayed turgor-driven growth indistinguishable in every respect from that in living cells, except the rate decelerated in the isolated walls while the living cells grew rapidly. The growth in the isolated walls was highly responsive to temperature, in contrast to the elastic extension that has been shown to be insensitive to similar temperatures. Consequently, strong inter-molecular bonds were responsible for growth and weak bonds for elastic extension. Boiling the walls gave the same results, indicating that enzyme activities were not controlling these bonds. However, pectin added to isolated walls reversed their growth deceler-ation and returned the rate to that in the living cells. The pectin was similar to that normally produced by the cytoplasm and deposited in the wall, suggesting that continued cytoplasmic input of pectin may play a role in sustaining turgor-driven growth in Chara. Key words: Cell wall, Chara corallina, cytoplasmic input, growth, intermolecular bonds, pectin, turgor pressure
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Turgor, temperature and the growth of plant cells: using Chara corallina as a model system
2000Co-Authors: Timothy E. Proseus, Guo-li Zhu, John S. BoyerAbstract:Rapid changes in turgor pressure (P) and temperature In most plant cells, turgor pressure (P) is required for (T) are giving new information about the mechanisms growth. The P must be above a minimum, and growth of plant growth. In the present work, single internode appears as a steady increase in size if P is steady (Cleland, cells of the large-celled alga Chara corallina were used 1971; Taiz et al., 1981; Taiz, 1984; Passioura, 1994)
F. A. Smith - One of the best experts on this subject based on the ideXlab platform.
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calcium salinity interactions affect ion transport in Chara corallina
Plant Cell and Environment, 1992Co-Authors: J. Whittington, F. A. SmithAbstract:Detached internodes of Chara corallina survived in solutions containing 100 mol m−3 NaCl when the external concentration of Ca2+ was greater than 1 mol m−3. Na+ influx was roughly proportional to external Na+ up to 100 mol m−3 NaCl. Na+ influx involved two components: a Ca2+-insensitive influx which allowed the passage of Na+ independently of external Ca2+; and a Ca2+-inhibitable mechanism where Na+ influx was inversely proportional to external Ca2+. The Ca2+-inhibitable Na+ influx was similar to the Ca2+-inhibitable K+ influx. Mg2+ and Ba2+ were able to substitute for Ca2+ in partially inhibiting Na+ influx in the absence of external Ca2+. The effect of Ca2+ appears specific to Na+ and K+ influx since the effects of a Ca2+-free solution on the influx of some other cations, anions and neutral compounds is small. It is suggested that Na+ influx via the Ca2+-inhibitable mechanism represents Na+ leakage through K+ channels and that cell death at high salinity occurs due to a cytotoxic Na+ influx via this mechanism.
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Calcium‐salinity interactions affect ion transport in Chara corallina
Plant Cell and Environment, 1992Co-Authors: J. Whittington, F. A. SmithAbstract:Detached internodes of Chara corallina survived in solutions containing 100 mol m−3 NaCl when the external concentration of Ca2+ was greater than 1 mol m−3. Na+ influx was roughly proportional to external Na+ up to 100 mol m−3 NaCl. Na+ influx involved two components: a Ca2+-insensitive influx which allowed the passage of Na+ independently of external Ca2+; and a Ca2+-inhibitable mechanism where Na+ influx was inversely proportional to external Ca2+. The Ca2+-inhibitable Na+ influx was similar to the Ca2+-inhibitable K+ influx. Mg2+ and Ba2+ were able to substitute for Ca2+ in partially inhibiting Na+ influx in the absence of external Ca2+. The effect of Ca2+ appears specific to Na+ and K+ influx since the effects of a Ca2+-free solution on the influx of some other cations, anions and neutral compounds is small. It is suggested that Na+ influx via the Ca2+-inhibitable mechanism represents Na+ leakage through K+ channels and that cell death at high salinity occurs due to a cytotoxic Na+ influx via this mechanism.
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Biophysical and Biochemical Regulation of Cytoplasmic pH in Chara corallina during Acid Loads
Journal of Experimental Botany, 1991Co-Authors: F. A. Smith, R. J. ReidAbstract:The contribution of membrane transport to regulation of cytoplasmic pH in Chara corallina has been measured during proton-loading by uptake of butyric acid
Koreaki Ogata - One of the best experts on this subject based on the ideXlab platform.
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Transduction of pressure signal to electrical signal upon sudden increase in turgor pressure in Chara corallina
Journal of Plant Research, 2013Co-Authors: Teruo Shimmen, Koreaki OgataAbstract:By taking advantage of large cell size of Chara corallina , we analyzed the membrane depolarization induced by decreased turgor pressure (Shimmen in J Plant Res 124:639–644, 2011 ). In the present study, the response to increased turgor pressure was analyzed. When internodes were incubated in media containing 200 mM dimethyl sulfoxide, their intracellular osmolality gradually increased and reached a steady level after about 3 h. Upon removal of dimethyl sulfoxide, turgor pressure quickly increased. In response to the increase in turgor pressure, the internodes generated a transient membrane depolarization at its nodal end. The refractory period was very long and it took about 2 h for full recovery after the depolarizing response. Involvement of protein synthesis in recovery from refractoriness was suggested, based on experiments using inhibitors.
Holger Dau - One of the best experts on this subject based on the ideXlab platform.
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biogenic manganese calcium oxides on the cell walls of the algae Chara corallina elemental composition atomic structure and water oxidation catalysis
European Journal of Inorganic Chemistry, 2014Co-Authors: Andreas Scholer, Ivelina Zaharieva, Mathias Wiechen, Philipp Kurz, Sebastian Zimmermann, Annemarie Manke, Christoph Plieth, Holger DauAbstract:Chara corallina freshwater algae produce brown deposits of manganese oxides on their cell wall surfaces when growing in manganese-rich media. We report on the formation, topology, composition, atomic structure, and catalytic activities of these biogenic manganese oxides (BMOs). The deposits are volcano shaped and exhibit 3–5 μm craters in their centers. Microfocus X-ray irradiation and detection of Characteristic X-ray fluorescence lines allowed elemental mapping at 5 μm spatial resolution and the identification of the volcano-shaped deposits as a Mn–Ca oxide. X-ray absorption spectroscopy (XAS) revealed a high-valent MnIII/IV oxide. The structural analysis involved XAS spectra collected for a single volcano at room temperature and for single cells at 20 K. On the basis of the XAS data, the oxides were identified as members of the birnessite family of layered manganese oxides containing di-μ-oxido-bridged MnIII/IVO6 octahedra as central building units. The deposits share structural motifs with synthetic water-oxidizing Mn–Ca oxides and with the Mn4Ca complex of photosystem II, the biological water-oxidation catalyst. Model reactions demonstrate low, but clearly detectable, activity of the manganese deposits for water-oxidation catalysis. The biogenic manganese oxides on the cell walls of Chara corallina thus represent an intriguing object to study how manganese-based catalysts for water oxidation are formed in a biological environment. The formation of BMOs in relation to cellular ion transport and the possibility of BMOs to fulfill a detoxification function in plants were also examined.
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Biogenic Manganese–Calcium Oxides on the Cell Walls of the Algae Chara corallina: Elemental Composition, Atomic Structure, and Water‐Oxidation Catalysis
European Journal of Inorganic Chemistry, 2013Co-Authors: Andreas Scholer, Ivelina Zaharieva, Mathias Wiechen, Philipp Kurz, Sebastian Zimmermann, Annemarie Manke, Christoph Plieth, Holger DauAbstract:Chara corallina freshwater algae produce brown deposits of manganese oxides on their cell wall surfaces when growing in manganese-rich media. We report on the formation, topology, composition, atomic structure, and catalytic activities of these biogenic manganese oxides (BMOs). The deposits are volcano shaped and exhibit 3–5 μm craters in their centers. Microfocus X-ray irradiation and detection of Characteristic X-ray fluorescence lines allowed elemental mapping at 5 μm spatial resolution and the identification of the volcano-shaped deposits as a Mn–Ca oxide. X-ray absorption spectroscopy (XAS) revealed a high-valent MnIII/IV oxide. The structural analysis involved XAS spectra collected for a single volcano at room temperature and for single cells at 20 K. On the basis of the XAS data, the oxides were identified as members of the birnessite family of layered manganese oxides containing di-μ-oxido-bridged MnIII/IVO6 octahedra as central building units. The deposits share structural motifs with synthetic water-oxidizing Mn–Ca oxides and with the Mn4Ca complex of photosystem II, the biological water-oxidation catalyst. Model reactions demonstrate low, but clearly detectable, activity of the manganese deposits for water-oxidation catalysis. The biogenic manganese oxides on the cell walls of Chara corallina thus represent an intriguing object to study how manganese-based catalysts for water oxidation are formed in a biological environment. The formation of BMOs in relation to cellular ion transport and the possibility of BMOs to fulfill a detoxification function in plants were also examined.