The Experts below are selected from a list of 2184 Experts worldwide ranked by ideXlab platform
Juan F. Martín - One of the best experts on this subject based on the ideXlab platform.
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Role of homoserine and threonine pathway intermediates as precursors for the biosynthesis of Aminoethoxyvinylglycine in Streptomyces sp. NRRL 5331
Microbiology, 2004Co-Authors: Mónica Fernández, Yolanda Cuadrado, Jesús F. Aparicio, Juan F. MartínAbstract:The genes hom, thrB and thrC, encoding homoserine dehydrogenase, homoserine kinase (HK) and threonine synthase, respectively, involved in the last steps of threonine biosynthesis, have been studied in Streptomyces sp. NRRL 5331, the producer of the ethylene synthetase inhibitor Aminoethoxyvinylglycine (AVG), in order to determine their role in the biosynthesis of AVG. Different null mutants were obtained by plasmid-mediated disruption of each of the three genes. thrC gene disruption had no effect on AVG production, while the disruption of thrB blocked HK activity and substantially reduced the yield of this metabolite, probably due to the accumulation of homoserine and/or methionine which have a negative effect on AVG biosynthesis. Disruption of hom (thrA) completely blocked AVG biosynthesis, indicating that homoserine lies at the branching point of the aspartic-acid-derived biosynthetic route that leads to AVG. The four carbon atoms of the vinylglycine moiety of AVG derive, therefore, from homoserine.
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Characterization of the ask-asd operon in Aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331.
Applied microbiology and biotechnology, 2003Co-Authors: Yolanda Cuadrado, Mónica Fernández, Eliseo Recio, Jesús F. Aparicio, Juan F. MartínAbstract:The first two genes of the threonine pathway, ask and asd, were cloned and sequenced from the Aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331. The two genes are organized in a bicistronic operon. ask, encoding the apartokinase (ASK), is located upstream from asd. The presence of a ribosome-binding site within the ask sequence suggests that this open reading frame encodes two overlapping proteins. The formation of both subunits of the aspartokinase from a single gene was studied using antibodies raised against the C-terminal end of the aspartokinase subunits. Disruption of asd results in a significant decrease of Aminoethoxyvinylglycine production, thus supporting the involvement of the ask-asd operon in the biosynthesis of this metabolite. This is the first report in which a gene cluster for the first two steps of Aminoethoxyvinylglycine biosynthesis is characterized.
Jose Beltrano - One of the best experts on this subject based on the ideXlab platform.
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drought stress syndrome in wheat is provoked by ethylene evolution imbalance and reversed by rewatering Aminoethoxyvinylglycine or sodium benzoate
Journal of Plant Growth Regulation, 1999Co-Authors: Jose Beltrano, Marta Guillermina Ronco, Edgardo R MontaldiAbstract:In this work we present evidence that the drought stress syndrome in the flag leaves and ears of wheat plants, provoked by the production of ethylene (shortening the grain filling period and lowering the grain weight) is reversed by the application of a free radical scavenger, sodium benzoate or the ethylene synthesis inhibitor, Aminoethoxyvinylglycine. Rehydration by watering also attenuated the detrimental effect of the water deficit. Consequently, the grain filling period was longer, the grain weight increased, and the total protein content was higher than that in plants watered regularly.
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Ethylene as promoter of wheat grain maturation and ear senescence
Plant Growth Regulation, 1994Co-Authors: Jose Beltrano, Edgardo R Montaldi, Alejandra Carbone, Juan Jose GuiametAbstract:This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g^−1FW h^−1 to a peak 1.53 nl g^−1FW h^−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g^−1FW h^−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
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Ethylene as promoter of wheat grain maturation and ear senescence
Plant Growth Regulation, 1994Co-Authors: Jose Beltrano, Edgardo R Montaldi, Alejandra Carbone, Juan Jose GuiametAbstract:This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g^−1FW h^−1 to a peak 1.53 nl g^−1FW h^−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g^−1FW h^−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
Edgardo R Montaldi - One of the best experts on this subject based on the ideXlab platform.
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drought stress syndrome in wheat is provoked by ethylene evolution imbalance and reversed by rewatering Aminoethoxyvinylglycine or sodium benzoate
Journal of Plant Growth Regulation, 1999Co-Authors: Jose Beltrano, Marta Guillermina Ronco, Edgardo R MontaldiAbstract:In this work we present evidence that the drought stress syndrome in the flag leaves and ears of wheat plants, provoked by the production of ethylene (shortening the grain filling period and lowering the grain weight) is reversed by the application of a free radical scavenger, sodium benzoate or the ethylene synthesis inhibitor, Aminoethoxyvinylglycine. Rehydration by watering also attenuated the detrimental effect of the water deficit. Consequently, the grain filling period was longer, the grain weight increased, and the total protein content was higher than that in plants watered regularly.
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Ethylene as promoter of wheat grain maturation and ear senescence
Plant Growth Regulation, 1994Co-Authors: Jose Beltrano, Edgardo R Montaldi, Alejandra Carbone, Juan Jose GuiametAbstract:This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g^−1FW h^−1 to a peak 1.53 nl g^−1FW h^−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g^−1FW h^−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
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Ethylene as promoter of wheat grain maturation and ear senescence
Plant Growth Regulation, 1994Co-Authors: Jose Beltrano, Edgardo R Montaldi, Alejandra Carbone, Juan Jose GuiametAbstract:This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g^−1FW h^−1 to a peak 1.53 nl g^−1FW h^−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g^−1FW h^−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
Juan Jose Guiamet - One of the best experts on this subject based on the ideXlab platform.
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Ethylene as promoter of wheat grain maturation and ear senescence
Plant Growth Regulation, 1994Co-Authors: Jose Beltrano, Edgardo R Montaldi, Alejandra Carbone, Juan Jose GuiametAbstract:This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g^−1FW h^−1 to a peak 1.53 nl g^−1FW h^−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g^−1FW h^−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
-
Ethylene as promoter of wheat grain maturation and ear senescence
Plant Growth Regulation, 1994Co-Authors: Jose Beltrano, Edgardo R Montaldi, Alejandra Carbone, Juan Jose GuiametAbstract:This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g^−1FW h^−1 to a peak 1.53 nl g^−1FW h^−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g^−1FW h^−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
Yolanda Cuadrado - One of the best experts on this subject based on the ideXlab platform.
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Role of homoserine and threonine pathway intermediates as precursors for the biosynthesis of Aminoethoxyvinylglycine in Streptomyces sp. NRRL 5331
Microbiology, 2004Co-Authors: Mónica Fernández, Yolanda Cuadrado, Jesús F. Aparicio, Juan F. MartínAbstract:The genes hom, thrB and thrC, encoding homoserine dehydrogenase, homoserine kinase (HK) and threonine synthase, respectively, involved in the last steps of threonine biosynthesis, have been studied in Streptomyces sp. NRRL 5331, the producer of the ethylene synthetase inhibitor Aminoethoxyvinylglycine (AVG), in order to determine their role in the biosynthesis of AVG. Different null mutants were obtained by plasmid-mediated disruption of each of the three genes. thrC gene disruption had no effect on AVG production, while the disruption of thrB blocked HK activity and substantially reduced the yield of this metabolite, probably due to the accumulation of homoserine and/or methionine which have a negative effect on AVG biosynthesis. Disruption of hom (thrA) completely blocked AVG biosynthesis, indicating that homoserine lies at the branching point of the aspartic-acid-derived biosynthetic route that leads to AVG. The four carbon atoms of the vinylglycine moiety of AVG derive, therefore, from homoserine.
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Characterization of the ask-asd operon in Aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331.
Applied microbiology and biotechnology, 2003Co-Authors: Yolanda Cuadrado, Mónica Fernández, Eliseo Recio, Jesús F. Aparicio, Juan F. MartínAbstract:The first two genes of the threonine pathway, ask and asd, were cloned and sequenced from the Aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331. The two genes are organized in a bicistronic operon. ask, encoding the apartokinase (ASK), is located upstream from asd. The presence of a ribosome-binding site within the ask sequence suggests that this open reading frame encodes two overlapping proteins. The formation of both subunits of the aspartokinase from a single gene was studied using antibodies raised against the C-terminal end of the aspartokinase subunits. Disruption of asd results in a significant decrease of Aminoethoxyvinylglycine production, thus supporting the involvement of the ask-asd operon in the biosynthesis of this metabolite. This is the first report in which a gene cluster for the first two steps of Aminoethoxyvinylglycine biosynthesis is characterized.
