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Acetosyringone

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Jianmin Chen – One of the best experts on this subject based on the ideXlab platform.

E W Nester – One of the best experts on this subject based on the ideXlab platform.

  • Dynamic structure of Agrobacterium tumefaciens Ti plasmids.
    Journal of bacteriology, 1993
    Co-Authors: C Fortin, E W Nester, C Marquis, P Dion
    Abstract:

    Agrobacterium tumefaciens C58F is a variant of strain C58 which generates a high proportion of avirulent mutants in the presence of the virulence (vir) gene inducer Acetosyringone. These mutants are altered in the Ti plasmid and do not respond to the Acetosyringone signal (C. Fortin, E. W. Nester, and P. Dion, J. Bacteriol. 174:5676-5685, 1992). The physical organization of the Ti plasmid was compared in strain C58 and its variant. One feature distinguishing pTiC58F from its parent plasmid was the presence of the insertion element IS426. Three copies of this element were detected in the strain C58 chromosome, whereas two additional copies were found in strain C58F, including one copy in the Ti plasmid. This particular copy of IS426 was associated with the region of arginine and nopaline catabolism of pTiC58F. Most of the avirulent mutants recovered following growth of strain C58F in the presence of Acetosyringone were complemented by clones carrying either virA or virG. Element IS426 was no longer found in the arginine and nopaline catabolism region of the Ti plasmids from the virA and virG mutants, but it resided in the particular KpnI fragment containing the modified vir locus. Behavior of a strain C58F derivative, which was inactivated in a chromosomal component required for the response to Acetosyringone, was consistent with the possibility that vir gene induction is essential to the massive production of avirulent mutants. Images

  • Growth inhibition and loss of virulence in cultures of Agrobacterium tumefaciens treated with Acetosyringone.
    Journal of bacteriology, 1992
    Co-Authors: C Fortin, E W Nester, P Dion
    Abstract:

    Acetosyringone, a phenolic inducer of the virulence (vir) genes of Agrobacterium tumefaciens, inhibited the growth of the nopaline-type strains T37 and C58 incubated under acidic conditions. In the course of a 6-day incubation with Acetosyringone, avirulent clones were produced in different proportions by strains T37 and C58 and also by a spontaneous variant of strain C58, denominated C58F. The proportion of avirulent clones in Acetosyringone-treated cultures often exceeded 50% for strains T37 and C58F and was of the order of 1% for strain C58. Control cultures not exposed to Acetosyringone did not yield avirulent clones. Two other vir inducers, sinapinic acid and syringaldehyde, also inhibited growth and promoted accumulation of avirulent clones in cultures of strains C58F and T37. On the other hand, various Acetosyringone analogs reported not to induce the vir genes did not act as growth inhibitors. All of the T37 and most of the C58F avirulent clones examined still carried a Ti plasmid. In all instances examined, avirulent clones still carrying a Ti plasmid were mutated in this plasmid. Mutants of strain C58F lacked the capacity to induce a virB::lacZ fusion in the presence of Acetosyringone. Images

  • mutants of the agrobacterium tumefaciens vira gene exhibiting Acetosyringone independent expression of the vir regulon
    Molecular Plant-microbe Interactions, 1991
    Co-Authors: R G Ankenbauer, E A Best, C A Palanca, E W Nester
    Abstract:

    Hydroxylamine-induced mutations in the virA gene of Agrobacterium tumefaciens that do not require the plant phenolic-inducing compound Acetosyringone for vir regulon induction were isolated. The isolation was based on the activation of both virB::lacZ and virE::cat fusions by mutant virA loci in the absence of Acetosyringone. Three of these virA(Ais) (Acetosyringone-independent signaling) mutants were characterized. All three mutants expressed a virB::lacZ fusion at high levels in the absence of Acetosyringone. One virA (Ais) mutant, virA112, exhibited vir gene expression in the absence of inducing monosaccharides and acidic growth conditions, both of which are normally required for vir gene induction. The phenotype of the virA112 mutant resulted from a glycine to glutamic acid change near His-474, the site of VirA autophosphorylation.

P Dion – One of the best experts on this subject based on the ideXlab platform.

  • Dynamic structure of Agrobacterium tumefaciens Ti plasmids.
    Journal of bacteriology, 1993
    Co-Authors: C Fortin, E W Nester, C Marquis, P Dion
    Abstract:

    Agrobacterium tumefaciens C58F is a variant of strain C58 which generates a high proportion of avirulent mutants in the presence of the virulence (vir) gene inducer Acetosyringone. These mutants are altered in the Ti plasmid and do not respond to the Acetosyringone signal (C. Fortin, E. W. Nester, and P. Dion, J. Bacteriol. 174:5676-5685, 1992). The physical organization of the Ti plasmid was compared in strain C58 and its variant. One feature distinguishing pTiC58F from its parent plasmid was the presence of the insertion element IS426. Three copies of this element were detected in the strain C58 chromosome, whereas two additional copies were found in strain C58F, including one copy in the Ti plasmid. This particular copy of IS426 was associated with the region of arginine and nopaline catabolism of pTiC58F. Most of the avirulent mutants recovered following growth of strain C58F in the presence of Acetosyringone were complemented by clones carrying either virA or virG. Element IS426 was no longer found in the arginine and nopaline catabolism region of the Ti plasmids from the virA and virG mutants, but it resided in the particular KpnI fragment containing the modified vir locus. Behavior of a strain C58F derivative, which was inactivated in a chromosomal component required for the response to Acetosyringone, was consistent with the possibility that vir gene induction is essential to the massive production of avirulent mutants. Images

  • Growth inhibition and loss of virulence in cultures of Agrobacterium tumefaciens treated with Acetosyringone.
    Journal of bacteriology, 1992
    Co-Authors: C Fortin, E W Nester, P Dion
    Abstract:

    Acetosyringone, a phenolic inducer of the virulence (vir) genes of Agrobacterium tumefaciens, inhibited the growth of the nopaline-type strains T37 and C58 incubated under acidic conditions. In the course of a 6-day incubation with Acetosyringone, avirulent clones were produced in different proportions by strains T37 and C58 and also by a spontaneous variant of strain C58, denominated C58F. The proportion of avirulent clones in Acetosyringone-treated cultures often exceeded 50% for strains T37 and C58F and was of the order of 1% for strain C58. Control cultures not exposed to Acetosyringone did not yield avirulent clones. Two other vir inducers, sinapinic acid and syringaldehyde, also inhibited growth and promoted accumulation of avirulent clones in cultures of strains C58F and T37. On the other hand, various Acetosyringone analogs reported not to induce the vir genes did not act as growth inhibitors. All of the T37 and most of the C58F avirulent clones examined still carried a Ti plasmid. In all instances examined, avirulent clones still carrying a Ti plasmid were mutated in this plasmid. Mutants of strain C58F lacked the capacity to induce a virB::lacZ fusion in the presence of Acetosyringone. Images

Shilai Hao – One of the best experts on this subject based on the ideXlab platform.

  • separation of high purity syringol and Acetosyringone from rice straw derived bio oil by combining the basification acidification process and column chromatography
    Electrophoresis, 2016
    Co-Authors: Shilai Hao, Kaifei Chen, Leichang Cao, Xiangdong Zhu, Gang Luo, Shicheng Zhang, Jianmin Chen
    Abstract:

    Numerous technologies have been used to reclaim valuable chemicals from bio-oil. In this study, a combination of the basification-acidification process and column chromatography was employed for the separation of high-purity syringol and Acetosyringone from rice straw-derived bio-oil. The optimal conditions for the basification-acidification process and the possible precipitation mechanism of the basification were explored. The results showed the following as the optimal conditions for the basification process: mass ratio of calcium hydroxide (Ca(OH)2 ) to bio-oil, 2.0; reaction temperature, 70°C; and reaction time, 30 min. The results also showed that 1.6 mol of hydrochloric acid (HCl) per gram of bio-oil was optimal for the acidification. The precipitation was found to proceed via a possible mechanism involving the reaction of the phenolic compounds in the bio-oil with Ca(OH)2 to produce a precipitate. After further separation by column chromatography, purities of 91.4 and 96.2% (from gas chromatography-mass spectrometry) were obtained for syringol and Acetosyringone, respectively. Their recoveries for the whole process were 73.0 and 39.3%, respectively.

  • Separation of high‐purity syringol and Acetosyringone from rice straw‐derived bio‐oil by combining the basification‐acidification process and column chromatography
    Electrophoresis, 2016
    Co-Authors: Shilai Hao, Kaifei Chen, Leichang Cao, Xiangdong Zhu, Gang Luo, Shicheng Zhang, Jianmin Chen
    Abstract:

    Numerous technologies have been used to reclaim valuable chemicals from bio-oil. In this study, a combination of the basification-acidification process and column chromatography was employed for the separation of high-purity syringol and Acetosyringone from rice straw-derived bio-oil. The optimal conditions for the basification-acidification process and the possible precipitation mechanism of the basification were explored. The results showed the following as the optimal conditions for the basification process: mass ratio of calcium hydroxide (Ca(OH)2 ) to bio-oil, 2.0; reaction temperature, 70°C; and reaction time, 30 min. The results also showed that 1.6 mol of hydrochloric acid (HCl) per gram of bio-oil was optimal for the acidification. The precipitation was found to proceed via a possible mechanism involving the reaction of the phenolic compounds in the bio-oil with Ca(OH)2 to produce a precipitate. After further separation by column chromatography, purities of 91.4 and 96.2% (from gas chromatography-mass spectrometry) were obtained for syringol and Acetosyringone, respectively. Their recoveries for the whole process were 73.0 and 39.3%, respectively.

Paul J J Hooykaas – One of the best experts on this subject based on the ideXlab platform.