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Enrique Cerdá-olmedo - One of the best experts on this subject based on the ideXlab platform.
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ent-Kaurene and squalene synthesis in Fusarium fujikuroi cell-free extracts.
Phytochemistry, 2000Co-Authors: Rafael Fernández-martín, Carlos E. Domenech, Enrique Cerdá-olmedo, Javier AvalosAbstract:Sterols and Gibberellins are the main terpenoids in the Ascomycete Fusarium fujikuroi. Their respective precursors squalene and ent-kaur-16-ene (henceforth called kaurene) were the main terpenoids synthesised from radioactive mevalonate by extracts of F. fujikuroi in vitro. Kaurene predominated when the extracts were obtained from mycelia engaged in Gibberellin production. Squalene predominated in all other cases, and particularly when the extracts were obtained from mutants with various defects in Gibberellin synthesis or nitrogen-fed wild-type cultures. New protein synthesis was required to maintain the production of Gibberellins in vivo and of kaurene in vitro, but not to maintain the capacity to produce squalene in vitro. Addition of a nitrogen source to cultures engaged in Gibberellin production caused a large, transient increase in the mycelial concentration of L-glutamine and abolished the accumulation of Gibberellins immediately and the capacity to produce kaurene later.
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Inhibition of Gibberellin biosynthesis by nitrate in Gibberella fujikuroi
FEBS letters, 1997Co-Authors: Rocı́o Sánchez-fernández, Javier Avalos, Enrique Cerdá-olmedoAbstract:Gibberellin production in Gibberella fujikuroi starts upon exhaustion of the nitrogen source. To determine the role of nitrate and ammonium in the regulation of Gibberellin biosynthesis we have isolated mutants that cannot use nitrate as a nitrogen source. Nitrate inhibited partially the production of Gibberellins in mutants devoid of nitrate reductase activity. The inhibition occurred whether nitrate was added before or after the onset of Gibberellin production. Addition of tungstate to the wild type mimicked the results with nitrate reductase mutants. We conclude that nitrate inhibits Gibberellin biosynthesis by itself, independently of the intracellular signal that conveys nitrogen availability.
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Gibberellin Biosynthesis in gib Mutants of Gibberella fujikuroi
The Journal of biological chemistry, 1995Co-Authors: Rafael Fernández-martn, Javier Avalos, Carlos E. Domenech, Alejandro F. Barrero, Fernando Reyes, Eduardo Cabrera, Peter M. Bramley, Enrique Cerdá-olmedoAbstract:Abstract The Ascomycete Gibberella fujikuroi synthesizes Gibberellins, fujenal, carotenoids, and other terpenoids. Twelve gib mutants, isolated through the modified Gibberellin fluorescence of their culture media, were subjected to chemical and biochemical analyses. Two mutants were specifically defective in the hydroxylation of carbon 13; their total Gibberellin production was normal, but their main Gibberellin was GA7 instead of GA3. Four mutants were blocked in the early reactions between geranylgeranyl pyrophosphate and 7-hydroxykaurenoic acid; two of them could not synthesize kaurene and another one was blocked in several oxidative steps. Six mutants had partial defects in early reactions, leading to the production of one-fifth to one-third of the wild type amounts of Gibberellins and fujenal. Two of these produced considerable amounts of kaurenolides due to a defect in the conversion of kaurenoic acid to 7-hydroxykaurenoic acid. Another one produced no carotenoids, but attempts to isolate mutants of reactions shared by the carotenoid and Gibberellin pathways failed. The gib mutations did not modify the ability of the fungus to live as a saprophyte.
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Genetics and Gibberellin production inGibberella fujikuroi
Antonie van Leeuwenhoek, 1994Co-Authors: Enrique Cerdá-olmedo, Rafael Fernández-martín, Javier AvalosAbstract:Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other Gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the Gibberellin biosynthetic pathway as established in Gibberella are described.
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Genetics and Gibberellin production in Gibberella fujikuroi
Antonie van Leeuwenhoek, 1994Co-Authors: Enrique Cerdá-olmedo, Rafael Fernández-martín, Javier AvalosAbstract:Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other Gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the Gibberellin biosynthetic pathway as established in Gibberella are described.
Javier Avalos - One of the best experts on this subject based on the ideXlab platform.
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ent-Kaurene and squalene synthesis in Fusarium fujikuroi cell-free extracts.
Phytochemistry, 2000Co-Authors: Rafael Fernández-martín, Carlos E. Domenech, Enrique Cerdá-olmedo, Javier AvalosAbstract:Sterols and Gibberellins are the main terpenoids in the Ascomycete Fusarium fujikuroi. Their respective precursors squalene and ent-kaur-16-ene (henceforth called kaurene) were the main terpenoids synthesised from radioactive mevalonate by extracts of F. fujikuroi in vitro. Kaurene predominated when the extracts were obtained from mycelia engaged in Gibberellin production. Squalene predominated in all other cases, and particularly when the extracts were obtained from mutants with various defects in Gibberellin synthesis or nitrogen-fed wild-type cultures. New protein synthesis was required to maintain the production of Gibberellins in vivo and of kaurene in vitro, but not to maintain the capacity to produce squalene in vitro. Addition of a nitrogen source to cultures engaged in Gibberellin production caused a large, transient increase in the mycelial concentration of L-glutamine and abolished the accumulation of Gibberellins immediately and the capacity to produce kaurene later.
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Inhibition of Gibberellin biosynthesis by nitrate in Gibberella fujikuroi
FEBS letters, 1997Co-Authors: Rocı́o Sánchez-fernández, Javier Avalos, Enrique Cerdá-olmedoAbstract:Gibberellin production in Gibberella fujikuroi starts upon exhaustion of the nitrogen source. To determine the role of nitrate and ammonium in the regulation of Gibberellin biosynthesis we have isolated mutants that cannot use nitrate as a nitrogen source. Nitrate inhibited partially the production of Gibberellins in mutants devoid of nitrate reductase activity. The inhibition occurred whether nitrate was added before or after the onset of Gibberellin production. Addition of tungstate to the wild type mimicked the results with nitrate reductase mutants. We conclude that nitrate inhibits Gibberellin biosynthesis by itself, independently of the intracellular signal that conveys nitrogen availability.
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Gibberellin Biosynthesis in gib Mutants of Gibberella fujikuroi
The Journal of biological chemistry, 1995Co-Authors: Rafael Fernández-martn, Javier Avalos, Carlos E. Domenech, Alejandro F. Barrero, Fernando Reyes, Eduardo Cabrera, Peter M. Bramley, Enrique Cerdá-olmedoAbstract:Abstract The Ascomycete Gibberella fujikuroi synthesizes Gibberellins, fujenal, carotenoids, and other terpenoids. Twelve gib mutants, isolated through the modified Gibberellin fluorescence of their culture media, were subjected to chemical and biochemical analyses. Two mutants were specifically defective in the hydroxylation of carbon 13; their total Gibberellin production was normal, but their main Gibberellin was GA7 instead of GA3. Four mutants were blocked in the early reactions between geranylgeranyl pyrophosphate and 7-hydroxykaurenoic acid; two of them could not synthesize kaurene and another one was blocked in several oxidative steps. Six mutants had partial defects in early reactions, leading to the production of one-fifth to one-third of the wild type amounts of Gibberellins and fujenal. Two of these produced considerable amounts of kaurenolides due to a defect in the conversion of kaurenoic acid to 7-hydroxykaurenoic acid. Another one produced no carotenoids, but attempts to isolate mutants of reactions shared by the carotenoid and Gibberellin pathways failed. The gib mutations did not modify the ability of the fungus to live as a saprophyte.
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Genetics and Gibberellin production inGibberella fujikuroi
Antonie van Leeuwenhoek, 1994Co-Authors: Enrique Cerdá-olmedo, Rafael Fernández-martín, Javier AvalosAbstract:Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other Gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the Gibberellin biosynthetic pathway as established in Gibberella are described.
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Genetics and Gibberellin production in Gibberella fujikuroi
Antonie van Leeuwenhoek, 1994Co-Authors: Enrique Cerdá-olmedo, Rafael Fernández-martín, Javier AvalosAbstract:Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other Gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the Gibberellin biosynthetic pathway as established in Gibberella are described.
Jo E. Readman - One of the best experts on this subject based on the ideXlab platform.
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Gibberellins A82 and A83 in seed of Lupinus albus
Phytochemistry, 1992Co-Authors: Paul Gaskin, Jake Macmillan, Gordon V. Hoad, I. K. Makinson, Jo E. ReadmanAbstract:Abstract Extracts from seeds of Lupinus albus at 14, 22, 35 and 52 days after anthesis were separated into free Gibberellins, ester conjugates and ether conjugates. Capillary GC-MS of the methylated and trimethylsilylated free Gibberellin fractions showed the presence of the known Gibberellins A 1 , A 3 , A 4 , A 17 , A 18 , A 23 and A 43 . In addition six new Gibberellin-like compounds were detected that corresponded to the addition of the elements of water to Gibberellins A 3 , A 4 , A 7 , A 14 , A 18 , and A 34 . Two of these components were identified by chemical syntheses as ent -3α,10β,17-trihydroxy-20-nor-16αHgibberellane-7,19-dioic acid 19,10-lactone and ent -3α,17-dihydroxy- 16αHgibberellane-7,19-dioic acid, which are accorded the Gibberellin numbers A 82 , and A 83 , respectively. ent -3α,10β,16β,17-Tetrahydroxy-20-nor-16βHgibberellane-7,19-dioic acid 19,10-lactone was also identified by synthesis of the methyl ester. Similar analyses of the hydrolysed ether conjugate fractions showed the presence of the known Gibberellins A 1 , A 3 , A 13 , A 18 and A 43 , the new Gibberellin A 82 and the ‘hydrated’ Gibberellins A 18 and A 34 ; the 15-ene isomers of Gibberellins A 13 and A 43 and the 16ξ17-epoxide of Gibberellin A 18 were also identified as probable artefacts. In the hydrolysed ester conjugate fractions the new Gibberellin A 82 and the ‘hydrated’ Gibberellin A 34 were detected. Gibberellin A 18 was by far the most abundant GA but quantitation of the GAs was not carried out.
Rafael Fernández-martín - One of the best experts on this subject based on the ideXlab platform.
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ent-Kaurene and squalene synthesis in Fusarium fujikuroi cell-free extracts.
Phytochemistry, 2000Co-Authors: Rafael Fernández-martín, Carlos E. Domenech, Enrique Cerdá-olmedo, Javier AvalosAbstract:Sterols and Gibberellins are the main terpenoids in the Ascomycete Fusarium fujikuroi. Their respective precursors squalene and ent-kaur-16-ene (henceforth called kaurene) were the main terpenoids synthesised from radioactive mevalonate by extracts of F. fujikuroi in vitro. Kaurene predominated when the extracts were obtained from mycelia engaged in Gibberellin production. Squalene predominated in all other cases, and particularly when the extracts were obtained from mutants with various defects in Gibberellin synthesis or nitrogen-fed wild-type cultures. New protein synthesis was required to maintain the production of Gibberellins in vivo and of kaurene in vitro, but not to maintain the capacity to produce squalene in vitro. Addition of a nitrogen source to cultures engaged in Gibberellin production caused a large, transient increase in the mycelial concentration of L-glutamine and abolished the accumulation of Gibberellins immediately and the capacity to produce kaurene later.
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Genetics and Gibberellin production inGibberella fujikuroi
Antonie van Leeuwenhoek, 1994Co-Authors: Enrique Cerdá-olmedo, Rafael Fernández-martín, Javier AvalosAbstract:Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other Gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the Gibberellin biosynthetic pathway as established in Gibberella are described.
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Genetics and Gibberellin production in Gibberella fujikuroi
Antonie van Leeuwenhoek, 1994Co-Authors: Enrique Cerdá-olmedo, Rafael Fernández-martín, Javier AvalosAbstract:Gibberella fujikuroi (Fusarium moniliforme) is a complex group of plant pathogens. Some strains produce gibberellic acid and other Gibberellins that promote growth and regulate various stages in plant development. The paper describes the research effort directed to development of genetic tools for this species. Furthermore the main features of the Gibberellin biosynthetic pathway as established in Gibberella are described.
Paul Gaskin - One of the best experts on this subject based on the ideXlab platform.
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Gibberellins A82 and A83 in seed of Lupinus albus
Phytochemistry, 1992Co-Authors: Paul Gaskin, Jake Macmillan, Gordon V. Hoad, I. K. Makinson, Jo E. ReadmanAbstract:Abstract Extracts from seeds of Lupinus albus at 14, 22, 35 and 52 days after anthesis were separated into free Gibberellins, ester conjugates and ether conjugates. Capillary GC-MS of the methylated and trimethylsilylated free Gibberellin fractions showed the presence of the known Gibberellins A 1 , A 3 , A 4 , A 17 , A 18 , A 23 and A 43 . In addition six new Gibberellin-like compounds were detected that corresponded to the addition of the elements of water to Gibberellins A 3 , A 4 , A 7 , A 14 , A 18 , and A 34 . Two of these components were identified by chemical syntheses as ent -3α,10β,17-trihydroxy-20-nor-16αHgibberellane-7,19-dioic acid 19,10-lactone and ent -3α,17-dihydroxy- 16αHgibberellane-7,19-dioic acid, which are accorded the Gibberellin numbers A 82 , and A 83 , respectively. ent -3α,10β,16β,17-Tetrahydroxy-20-nor-16βHgibberellane-7,19-dioic acid 19,10-lactone was also identified by synthesis of the methyl ester. Similar analyses of the hydrolysed ether conjugate fractions showed the presence of the known Gibberellins A 1 , A 3 , A 13 , A 18 and A 43 , the new Gibberellin A 82 and the ‘hydrated’ Gibberellins A 18 and A 34 ; the 15-ene isomers of Gibberellins A 13 and A 43 and the 16ξ17-epoxide of Gibberellin A 18 were also identified as probable artefacts. In the hydrolysed ester conjugate fractions the new Gibberellin A 82 and the ‘hydrated’ Gibberellin A 34 were detected. Gibberellin A 18 was by far the most abundant GA but quantitation of the GAs was not carried out.