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Marie-françoise Petit-glatron - One of the best experts on this subject based on the ideXlab platform.
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Differential Dependence of Levansucrase and α-Amylase Secretion on SecA (Div) during the Exponential Phase of Growth of Bacillus subtilis
Microbiology, 2016Co-Authors: Laurence Leloup, Régis Chambert, Arnold J. M. Driessen, Roland Freudl, Marie-françoise Petit-glatronAbstract:SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32(Hy) Bacillus subtilis strain in logarithmic Phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary Phase. Modulation of the level of functional SecA during the Exponential Phase of growth affected differently the secretion of levansucrase and α-amylase overexpressed under the control of the sacB leader region. The level of SecA was reduced in the presence of sodium azide and in the div341 thermosensitive mutant at nonpermissive temperatures. Overproduction of SecA was obtained with a multicopy plasmid bearing secA. The gradual decrease of the SecA level reduced the yield of secreted levansucrase with a concomitant accumulation of unprocessed precursor in the cells, while an increase in the SecA level resulted in an elevation of the production of exocellular levansucrase. In contrast, α-amylase secretion was almost unaffected by high concentrations of sodium azide or by very low levels of SecA. Secretion defects were apparent only under conditions of strong SecA deprivation of the cell. These data demonstrate that the α-amylase and levansucrase precursors markedly differ in their dependency on SecA for secretion. It is suggested that these precursors differ in their binding affinities for SecA.
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Differential dependence of levansucrase and alpha-amylase secretion on SecA (Div) during the Exponential Phase of growth of Bacillus subtilis
Journal of Bacteriology, 1999Co-Authors: Laurence Leloup, Régis Chambert, Arnold J. M. Driessen, Roland Freudl, Marie-françoise Petit-glatronAbstract:SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32 (Hy) Bacillus subtilis strain in logarithmic Phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary Phase. Modulation of the level of functional SecA during the Exponential Phase of growth affected differently the secretion of levansucrase and α-amylase overexpressed under the control of the sacB leader region. The level of SecA was reduced in the presence of sodium azide and in the div341 thermosensitive mutant at nonpermissive temperatures. Overproduction of SecA was obtained with a multicopy plasmid bearing secA . The gradual decrease of the SecA level reduced the yield of secreted levansucrase with a concomitant accumulation of unprocessed precursor in the cells, while an increase in the SecA level resulted in an elevation of the production of exocellular levansucrase. In contrast, α-amylase secretion was almost unaffected by high concentrations of sodium azide or by very low levels of SecA. Secretion defects were apparent only under conditions of strong SecA deprivation of the cell. These data demonstrate that the α-amylase and levansucrase precursors markedly differ in their dependency on SecA for secretion. It is suggested that these precursors differ in their binding affinities for SecA.
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Kinetics of the secretion of Bacillus subtilis levanase overproduced during the Exponential Phase of growth.
Microbiology, 1999Co-Authors: Laurence Leloup, Marie-françoise Petit-glatron, Régis Chambert, Jérome Le SauxAbstract:The Bacillus subtilis levanase structural gene sacC was expressed under the regulated control of sacR, the inducible levansucrase leader region, in a degU32(Hy) strain. In this genetic context, exocellular levanase is overproduced (0·5% of total protein) during the Exponential Phase of growth upon induction by sucrose at 37 ° and pH 7. No precursor form that comprised a signal peptide was detected in pulse-chase experiments. The subsequent release of the cell-associated processed protein is a slow event (t 1/2 = 80 · 10 s). The unfolding-folding transition of pure levanase monitored in vitro by the resistance to proteolysis was achieved within the same time range (t 1/2 = 50 s) under the same conditions of pH and temperature. Calcium ions, which modulate the rate and the yield of refolding, have a low affinity for the protein. Comparison of these results with those obtained previously with levansucrase and α-amylase overproduced in the same genetic and physiological context suggests that the precursor processing is more efficient in levanase and α-amylase than in levansucrase. This discrepancy could lie in information borne by the signal peptide sequence of these exoproteins. However, the rate of the ultimate stage of release of these three proteins, which includes the passage through the cell wall, is correlated with the rate of folding and appears to be independent of their molecular size.
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Kinetics of the secretion of Bacillus subtilis levanase overproduced during the Exponential Phase of growth.
Microbiology (Reading England), 1999Co-Authors: Laurence Leloup, Marie-françoise Petit-glatron, Régis Chambert, Jérome Le SauxAbstract:The Bacillus subtilis levanase structural gene sacC was expressed under the regulated control of sacR, the inducible levansucrase leader region, in a degU32(Hy) strain. In this genetic context, exocellular levanase is overproduced (0.5% of total protein) during the Exponential Phase of growth upon induction by sucrose at 37 degrees C and pH 7. No precursor form that comprised a signal peptide was detected in pulse-chase experiments. The subsequent release of the cell-associated processed protein is a slow event (t(1,2) = 80+/-10 s). The unfolding-folding transition of pure levanase monitored in vitro by the resistance to proteolysis was achieved within the same time range (t(1/2) = 50 s) under the same conditions of pH and temperature. Calcium ions, which modulate the rate and the yield of refolding, have a low affinity for the protein. Comparison of these results with those obtained previously with levansucrase and alpha-amylase overproduced in the same genetic and physiological context suggests that the precursor processing is more efficient in levanase and alpha-amylase than in levansucrase. This discrepancy could lie in information borne by the signal peptide sequence of these exoproteins. However, the rate of the ultimate stage of release of these three proteins, which includes the passage through the cell wall, is correlated with the rate of folding and appears to be independent of their molecular size.
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Characterization of the rate-limiting step of the secretion of Bacillus subtilis α-amylase overproduced during the Exponential Phase of growth
Microbiology, 1997Co-Authors: Laurence Leloup, Régis Chambert, El Arbi Haddaoui, Marie-françoise Petit-glatronAbstract:The Bacillus subtilis α-amylase gene, amyE, was expressed under the regulated control of sacR, the levansucrase leader region. The gene fusion including the complete amyE coding sequence with the signal peptide sequence was integrated into the chromosome of a degU32(Hy) strain deleted of the sacB DNA fragment. In this genetic context, α-amylase is produced in the culture supernatant at a high level (2% of total protein) during the Exponential Phase of growth upon induction by sucrose. Pulse-chase experiments showed that the rate-limiting step (t 1/2 = 120 s) of the secretion process is the release of a cell-associated precursor form whose signal peptide has been cleaved. The efficiency of this ultimate step of secretion decreased dramatically in the presence of a metal chelator (EDTA) or when the cells were converted to protoplasts. The hypothesis that this step is tightly coupled with the folding process of α-amylase occurring within the cell wall environment was substantiated by in vitro folding studies. The unfolding-folding transition, monitored by the resistance to proteolysis, was achieved within the same time range (t 1/2 = 60 s) and required the presence of calcium. This metal requirement could possibly be satisfied in vivo by the integrity of the cell wail. The t 1/2 of the α-amylase release step is double that of levansucrase, although their folding rates are similar. This perhaps indicates that the passage through the cell wall may depend on parietal properties (e.g. metal ion binding and porosity) and on certain intrinsic properties of the protein (molecular mass and folding properties).
Laurence Leloup - One of the best experts on this subject based on the ideXlab platform.
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Differential Dependence of Levansucrase and α-Amylase Secretion on SecA (Div) during the Exponential Phase of Growth of Bacillus subtilis
Microbiology, 2016Co-Authors: Laurence Leloup, Régis Chambert, Arnold J. M. Driessen, Roland Freudl, Marie-françoise Petit-glatronAbstract:SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32(Hy) Bacillus subtilis strain in logarithmic Phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary Phase. Modulation of the level of functional SecA during the Exponential Phase of growth affected differently the secretion of levansucrase and α-amylase overexpressed under the control of the sacB leader region. The level of SecA was reduced in the presence of sodium azide and in the div341 thermosensitive mutant at nonpermissive temperatures. Overproduction of SecA was obtained with a multicopy plasmid bearing secA. The gradual decrease of the SecA level reduced the yield of secreted levansucrase with a concomitant accumulation of unprocessed precursor in the cells, while an increase in the SecA level resulted in an elevation of the production of exocellular levansucrase. In contrast, α-amylase secretion was almost unaffected by high concentrations of sodium azide or by very low levels of SecA. Secretion defects were apparent only under conditions of strong SecA deprivation of the cell. These data demonstrate that the α-amylase and levansucrase precursors markedly differ in their dependency on SecA for secretion. It is suggested that these precursors differ in their binding affinities for SecA.
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Differential dependence of levansucrase and alpha-amylase secretion on SecA (Div) during the Exponential Phase of growth of Bacillus subtilis
Journal of Bacteriology, 1999Co-Authors: Laurence Leloup, Régis Chambert, Arnold J. M. Driessen, Roland Freudl, Marie-françoise Petit-glatronAbstract:SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32 (Hy) Bacillus subtilis strain in logarithmic Phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary Phase. Modulation of the level of functional SecA during the Exponential Phase of growth affected differently the secretion of levansucrase and α-amylase overexpressed under the control of the sacB leader region. The level of SecA was reduced in the presence of sodium azide and in the div341 thermosensitive mutant at nonpermissive temperatures. Overproduction of SecA was obtained with a multicopy plasmid bearing secA . The gradual decrease of the SecA level reduced the yield of secreted levansucrase with a concomitant accumulation of unprocessed precursor in the cells, while an increase in the SecA level resulted in an elevation of the production of exocellular levansucrase. In contrast, α-amylase secretion was almost unaffected by high concentrations of sodium azide or by very low levels of SecA. Secretion defects were apparent only under conditions of strong SecA deprivation of the cell. These data demonstrate that the α-amylase and levansucrase precursors markedly differ in their dependency on SecA for secretion. It is suggested that these precursors differ in their binding affinities for SecA.
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Kinetics of the secretion of Bacillus subtilis levanase overproduced during the Exponential Phase of growth.
Microbiology, 1999Co-Authors: Laurence Leloup, Marie-françoise Petit-glatron, Régis Chambert, Jérome Le SauxAbstract:The Bacillus subtilis levanase structural gene sacC was expressed under the regulated control of sacR, the inducible levansucrase leader region, in a degU32(Hy) strain. In this genetic context, exocellular levanase is overproduced (0·5% of total protein) during the Exponential Phase of growth upon induction by sucrose at 37 ° and pH 7. No precursor form that comprised a signal peptide was detected in pulse-chase experiments. The subsequent release of the cell-associated processed protein is a slow event (t 1/2 = 80 · 10 s). The unfolding-folding transition of pure levanase monitored in vitro by the resistance to proteolysis was achieved within the same time range (t 1/2 = 50 s) under the same conditions of pH and temperature. Calcium ions, which modulate the rate and the yield of refolding, have a low affinity for the protein. Comparison of these results with those obtained previously with levansucrase and α-amylase overproduced in the same genetic and physiological context suggests that the precursor processing is more efficient in levanase and α-amylase than in levansucrase. This discrepancy could lie in information borne by the signal peptide sequence of these exoproteins. However, the rate of the ultimate stage of release of these three proteins, which includes the passage through the cell wall, is correlated with the rate of folding and appears to be independent of their molecular size.
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Kinetics of the secretion of Bacillus subtilis levanase overproduced during the Exponential Phase of growth.
Microbiology (Reading England), 1999Co-Authors: Laurence Leloup, Marie-françoise Petit-glatron, Régis Chambert, Jérome Le SauxAbstract:The Bacillus subtilis levanase structural gene sacC was expressed under the regulated control of sacR, the inducible levansucrase leader region, in a degU32(Hy) strain. In this genetic context, exocellular levanase is overproduced (0.5% of total protein) during the Exponential Phase of growth upon induction by sucrose at 37 degrees C and pH 7. No precursor form that comprised a signal peptide was detected in pulse-chase experiments. The subsequent release of the cell-associated processed protein is a slow event (t(1,2) = 80+/-10 s). The unfolding-folding transition of pure levanase monitored in vitro by the resistance to proteolysis was achieved within the same time range (t(1/2) = 50 s) under the same conditions of pH and temperature. Calcium ions, which modulate the rate and the yield of refolding, have a low affinity for the protein. Comparison of these results with those obtained previously with levansucrase and alpha-amylase overproduced in the same genetic and physiological context suggests that the precursor processing is more efficient in levanase and alpha-amylase than in levansucrase. This discrepancy could lie in information borne by the signal peptide sequence of these exoproteins. However, the rate of the ultimate stage of release of these three proteins, which includes the passage through the cell wall, is correlated with the rate of folding and appears to be independent of their molecular size.
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Characterization of the rate-limiting step of the secretion of Bacillus subtilis α-amylase overproduced during the Exponential Phase of growth
Microbiology, 1997Co-Authors: Laurence Leloup, Régis Chambert, El Arbi Haddaoui, Marie-françoise Petit-glatronAbstract:The Bacillus subtilis α-amylase gene, amyE, was expressed under the regulated control of sacR, the levansucrase leader region. The gene fusion including the complete amyE coding sequence with the signal peptide sequence was integrated into the chromosome of a degU32(Hy) strain deleted of the sacB DNA fragment. In this genetic context, α-amylase is produced in the culture supernatant at a high level (2% of total protein) during the Exponential Phase of growth upon induction by sucrose. Pulse-chase experiments showed that the rate-limiting step (t 1/2 = 120 s) of the secretion process is the release of a cell-associated precursor form whose signal peptide has been cleaved. The efficiency of this ultimate step of secretion decreased dramatically in the presence of a metal chelator (EDTA) or when the cells were converted to protoplasts. The hypothesis that this step is tightly coupled with the folding process of α-amylase occurring within the cell wall environment was substantiated by in vitro folding studies. The unfolding-folding transition, monitored by the resistance to proteolysis, was achieved within the same time range (t 1/2 = 60 s) and required the presence of calcium. This metal requirement could possibly be satisfied in vivo by the integrity of the cell wail. The t 1/2 of the α-amylase release step is double that of levansucrase, although their folding rates are similar. This perhaps indicates that the passage through the cell wall may depend on parietal properties (e.g. metal ion binding and porosity) and on certain intrinsic properties of the protein (molecular mass and folding properties).
Régis Chambert - One of the best experts on this subject based on the ideXlab platform.
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Differential Dependence of Levansucrase and α-Amylase Secretion on SecA (Div) during the Exponential Phase of Growth of Bacillus subtilis
Microbiology, 2016Co-Authors: Laurence Leloup, Régis Chambert, Arnold J. M. Driessen, Roland Freudl, Marie-françoise Petit-glatronAbstract:SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32(Hy) Bacillus subtilis strain in logarithmic Phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary Phase. Modulation of the level of functional SecA during the Exponential Phase of growth affected differently the secretion of levansucrase and α-amylase overexpressed under the control of the sacB leader region. The level of SecA was reduced in the presence of sodium azide and in the div341 thermosensitive mutant at nonpermissive temperatures. Overproduction of SecA was obtained with a multicopy plasmid bearing secA. The gradual decrease of the SecA level reduced the yield of secreted levansucrase with a concomitant accumulation of unprocessed precursor in the cells, while an increase in the SecA level resulted in an elevation of the production of exocellular levansucrase. In contrast, α-amylase secretion was almost unaffected by high concentrations of sodium azide or by very low levels of SecA. Secretion defects were apparent only under conditions of strong SecA deprivation of the cell. These data demonstrate that the α-amylase and levansucrase precursors markedly differ in their dependency on SecA for secretion. It is suggested that these precursors differ in their binding affinities for SecA.
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Differential dependence of levansucrase and alpha-amylase secretion on SecA (Div) during the Exponential Phase of growth of Bacillus subtilis
Journal of Bacteriology, 1999Co-Authors: Laurence Leloup, Régis Chambert, Arnold J. M. Driessen, Roland Freudl, Marie-françoise Petit-glatronAbstract:SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32 (Hy) Bacillus subtilis strain in logarithmic Phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary Phase. Modulation of the level of functional SecA during the Exponential Phase of growth affected differently the secretion of levansucrase and α-amylase overexpressed under the control of the sacB leader region. The level of SecA was reduced in the presence of sodium azide and in the div341 thermosensitive mutant at nonpermissive temperatures. Overproduction of SecA was obtained with a multicopy plasmid bearing secA . The gradual decrease of the SecA level reduced the yield of secreted levansucrase with a concomitant accumulation of unprocessed precursor in the cells, while an increase in the SecA level resulted in an elevation of the production of exocellular levansucrase. In contrast, α-amylase secretion was almost unaffected by high concentrations of sodium azide or by very low levels of SecA. Secretion defects were apparent only under conditions of strong SecA deprivation of the cell. These data demonstrate that the α-amylase and levansucrase precursors markedly differ in their dependency on SecA for secretion. It is suggested that these precursors differ in their binding affinities for SecA.
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Kinetics of the secretion of Bacillus subtilis levanase overproduced during the Exponential Phase of growth.
Microbiology, 1999Co-Authors: Laurence Leloup, Marie-françoise Petit-glatron, Régis Chambert, Jérome Le SauxAbstract:The Bacillus subtilis levanase structural gene sacC was expressed under the regulated control of sacR, the inducible levansucrase leader region, in a degU32(Hy) strain. In this genetic context, exocellular levanase is overproduced (0·5% of total protein) during the Exponential Phase of growth upon induction by sucrose at 37 ° and pH 7. No precursor form that comprised a signal peptide was detected in pulse-chase experiments. The subsequent release of the cell-associated processed protein is a slow event (t 1/2 = 80 · 10 s). The unfolding-folding transition of pure levanase monitored in vitro by the resistance to proteolysis was achieved within the same time range (t 1/2 = 50 s) under the same conditions of pH and temperature. Calcium ions, which modulate the rate and the yield of refolding, have a low affinity for the protein. Comparison of these results with those obtained previously with levansucrase and α-amylase overproduced in the same genetic and physiological context suggests that the precursor processing is more efficient in levanase and α-amylase than in levansucrase. This discrepancy could lie in information borne by the signal peptide sequence of these exoproteins. However, the rate of the ultimate stage of release of these three proteins, which includes the passage through the cell wall, is correlated with the rate of folding and appears to be independent of their molecular size.
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Kinetics of the secretion of Bacillus subtilis levanase overproduced during the Exponential Phase of growth.
Microbiology (Reading England), 1999Co-Authors: Laurence Leloup, Marie-françoise Petit-glatron, Régis Chambert, Jérome Le SauxAbstract:The Bacillus subtilis levanase structural gene sacC was expressed under the regulated control of sacR, the inducible levansucrase leader region, in a degU32(Hy) strain. In this genetic context, exocellular levanase is overproduced (0.5% of total protein) during the Exponential Phase of growth upon induction by sucrose at 37 degrees C and pH 7. No precursor form that comprised a signal peptide was detected in pulse-chase experiments. The subsequent release of the cell-associated processed protein is a slow event (t(1,2) = 80+/-10 s). The unfolding-folding transition of pure levanase monitored in vitro by the resistance to proteolysis was achieved within the same time range (t(1/2) = 50 s) under the same conditions of pH and temperature. Calcium ions, which modulate the rate and the yield of refolding, have a low affinity for the protein. Comparison of these results with those obtained previously with levansucrase and alpha-amylase overproduced in the same genetic and physiological context suggests that the precursor processing is more efficient in levanase and alpha-amylase than in levansucrase. This discrepancy could lie in information borne by the signal peptide sequence of these exoproteins. However, the rate of the ultimate stage of release of these three proteins, which includes the passage through the cell wall, is correlated with the rate of folding and appears to be independent of their molecular size.
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Characterization of the rate-limiting step of the secretion of Bacillus subtilis α-amylase overproduced during the Exponential Phase of growth
Microbiology, 1997Co-Authors: Laurence Leloup, Régis Chambert, El Arbi Haddaoui, Marie-françoise Petit-glatronAbstract:The Bacillus subtilis α-amylase gene, amyE, was expressed under the regulated control of sacR, the levansucrase leader region. The gene fusion including the complete amyE coding sequence with the signal peptide sequence was integrated into the chromosome of a degU32(Hy) strain deleted of the sacB DNA fragment. In this genetic context, α-amylase is produced in the culture supernatant at a high level (2% of total protein) during the Exponential Phase of growth upon induction by sucrose. Pulse-chase experiments showed that the rate-limiting step (t 1/2 = 120 s) of the secretion process is the release of a cell-associated precursor form whose signal peptide has been cleaved. The efficiency of this ultimate step of secretion decreased dramatically in the presence of a metal chelator (EDTA) or when the cells were converted to protoplasts. The hypothesis that this step is tightly coupled with the folding process of α-amylase occurring within the cell wall environment was substantiated by in vitro folding studies. The unfolding-folding transition, monitored by the resistance to proteolysis, was achieved within the same time range (t 1/2 = 60 s) and required the presence of calcium. This metal requirement could possibly be satisfied in vivo by the integrity of the cell wail. The t 1/2 of the α-amylase release step is double that of levansucrase, although their folding rates are similar. This perhaps indicates that the passage through the cell wall may depend on parietal properties (e.g. metal ion binding and porosity) and on certain intrinsic properties of the protein (molecular mass and folding properties).
Olivier Turc - One of the best experts on this subject based on the ideXlab platform.
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A whole‐plant analysis of the dynamics of expansion of individual leaves of two sunflower hybrids
Journal of Experimental Botany, 2003Co-Authors: Guillermo A. A. Dosio, Hervé Rey, Jérémie Lecoeur, Natalia G. Izquierdo, Luis A. N. Aguirrezábal, François Tardieu, Olivier TurcAbstract:Common features in the time-course of expansion of leaves which considerably differed in final area, due to phytomer position, growing conditions and genotype, were identified. Leaf development consisted of two Phases of Exponential growth, followed by a third Phase of continuous decrease of the relative expansion rate. The rate and the duration of the first Exponential Phase were common to all phytomers, growing conditions and genotypes. Leaves differed in the rate and the duration of the second Exponential Phase. The decrease of the relative expansion rate during the third Phase depended on neither genotype nor growing conditions. It was phytomerdependent and was deduced from the rate of the second Phase via a parameter common to all cases studied. Differences in final leaf area among growing conditions were linked to different expansion rates during the second Exponential Phase. The duration of the Phases at any given phytomer position was the same for the two hybrids in different growing conditions. The dates of developmental events (initiation, end of the two Exponential Phases, full expansion), and the rate of the second Exponential Phase, were related to phytomer position, defining a strict pattern of leaf development at the whole plant level. Using this framework simplified the analysis of the response of leaf expansion to genotype and environment.
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A whole-plant analysis of the dynamics of expansion of individual leaves of two sunflower hybrids
Journal of Experimental Botany, 2003Co-Authors: Guillermo A. A. Dosio, Hervé Rey, Jérémie Lecoeur, Natalia G. Izquierdo, Luis A. N. Aguirrezábal, François Tardieu, Olivier TurcAbstract:Common features in the time-course of expansion of leaves which considerably differed in final area, due to phytomer position, growing conditions and genotype, were identified. Leaf development consisted of two Phases of Exponential growth, followed by a third Phase of continuous decrease of the relative expansion rate. The rate and the duration of the first Exponential Phase were common to all phytomers, growing conditions and genotypes. Leaves differed in the rate and the duration of the second Exponential Phase. The decrease of the relative expansion rate during the third Phase depended on neither genotype nor growing conditions. It was phytomer-dependent and was deduced from the rate of the second Phase via a parameter common to all cases studied. Differences in final leaf area among growing conditions were linked to different expansion rates during the second Exponential Phase. The duration of the Phases at any given phytomer position was the same for the two hybrids in different growing conditions. The dates of developmental events (initiation, end of the two Exponential Phases, full expansion), and the rate of the second Exponential Phase, were related to phytomer position, defining a strict pattern of leaf development at the whole plant level. Using this framework simplified the analysis of the response of leaf expansion to genotype and environment.
Ángel Serrano-aroca - One of the best experts on this subject based on the ideXlab platform.
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Direct spectrophotometric method to determine cell density of Isochrysis galbana in serial batch cultures from a larger scale fed-batch culture in Exponential Phase
Proceedings of MOL2NET 2017 International Conference on Multidisciplinary Sciences 3rd edition, 2017Co-Authors: Jerónimo Chirivella-martorell, Ángel Serrano-arocaAbstract:In this work, a very useful and accurate procedure, based on the spectrophotometric method published by the American Public Health Association in the Standards Methods for the Examination of Water and Wastewater, was developed to determine cell density of Isochrysis galbana performing a single direct absorbance measurement in Exponential Phase of growth, which is the desirable operating mode for any microalgae production plant. Thus, Isochrysis galbana was cultured in serial batch cultures from a larger scale fed-batch culture. The growth performance of this species of microalgae under laboratory conditions was analysed by spectrophotometry at different wavelengths and cell counting in a haemocytometer (Neubauer chamber) showing that doubling times and cell death increased with increasing initial cell density. Besides, it was demonstrated that the absorbance of these cultures followed a linear trend as a function of time and cell density during the Exponential Phase of growth, results in which the developed direct method is based on. https://www.ucv.es/investigacion/publicaciones/catalogo-de-revistas/revista-nereis (NEREIS No9)
