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Hiroshi Kouchi - One of the best experts on this subject based on the ideXlab platform.
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responses of a model legume lotus japonicus to lipochitin oligosaccharide nodulation factors purified from mesorhizobium loti jrl501
Molecular Plant-microbe Interactions, 2001Co-Authors: Shinobu Niwa, Haruko Imaizumianraku, Svetlana A Chechetka, Masumi Ishizaka, Akira Ikuta, Masayoshi Kawaguchi, Hiroshi KouchiAbstract:Lotus japonicus has been proposed as a model legume for molecular genetic studies of symbiotic plant-microbe interactions leading to the fixation of atmospheric nitrogen. Lipochitin oligosaccharides (LCOs), or Nod factors, were isolated from the culture of Mesorhizobium loti strain JRL501 (MAFF303099), an efficient microsymbiont of L. japonicus B-129 cv. Gifu. High-performance liquid chromatography and mass spectrometric analyses allowed us to identify at least five different structures of LCOs that were produced by JRL501. The major component was NodMl-V(C18:1, Me, Cb, AcFuc), an N-acetyl-glucosamine pentamer in which the nonreducing residue is N-acylated with a C18:1 acyl moiety, N-methylated, and carries a Carbamoyl Group and the reducing N-acetyl-glucosamine residue is substituted with 4-O-acetyl-fucose. Additional novel LCO structures bearing fucose instead of acetyl-fucose at the reducing end were identified. Mixtures of these LCOs could elicit abundant root hair deformation on L. japonicus roots at...
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responses of a model legume lotus japonicus to lipochitin oligosaccharide nodulation factors purified from mesorhizobium loti jrl501
Molecular Plant-microbe Interactions, 2001Co-Authors: Sinobu Niwa, Svetlana A Chechetka, Masumi Ishizaka, Akira Ikuta, Masayoshi Kawaguchi, H Imazumianraku, Hiroshi KouchiAbstract:Lotus japonicus has been proposed as a model legume for molecular genetic studies of symbiotic plant-microbe interactions leading to the fixation of atmospheric nitrogen. Lipochitin oligosaccharides (LCOs), or Nod factors, were isolated from the culture of Mesorhizobium loti strain JRL501 (MAFF303099), an efficient microsymbiont of L. japonicus B-129 cv. Gifu. High-performance liquid chromatography and mass spectrometric analyses allowed us to identify at least five different structures of LCOs that were produced by JRL501. The major component was NodMl-V(C18:1, Me, Cb, AcFuc), an N-acetyl-glucosamine pentamer in which the nonreducing residue is N-acylated with a C18:1 acyl moiety, N-methylated, and carries a Carbamoyl Group and the reducing N-acetylglucosamine residue is substituted with 4-O-acetyl-fucose. Additional novel LCO structures bearing fucose instead of acetyl-fucose at the reducing end were identified. Mixtures of these LCOs could elicit abundant root hair deformation on L. japonicus roots at a concentration of 10(-7) to 10(-9) M. Spot inoculation of a few nanograms of LCOs on L. japonicus roots induced the formation of nodule primordia in which the early nodulin genes, ENOD40 and ENOD2, were expressed in a tissue-specific manner. We also observed the formation of a cytoplasmic bridge (preinfection thread) in the swollen outermost cortical cells. This is the first description of cytoplasmic bridge formation by purified LCOs alone in a legume-forming determinate nodules.
Li Niu - One of the best experts on this subject based on the ideXlab platform.
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Mechanism of inhibition of the GluA1 AMPA receptor channel opening by the 2, 3-benzodiazepine compound GYKI 52466 and a N-methyl-Carbamoyl derivative. Biochemistry 2014;53:3033–41
2016Co-Authors: Congzhou Wang, Li NiuAbstract:ABSTRACT: 2,3-Benzodiazepine derivatives, also known as GYKI compounds, represent a Group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors. Here we investigate the mechanism of inhibition of the GluA1 channel opening and the site of inhibition by GYKI 52466 and its N-3 methyl-Carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the brain function. Excessive activity and elevated expression of GluA1, however, has been implicated in a number of neurological disorders. Using a laser-pulse photolysis technique, which provides ∼60 μs resolution, we measured the effect of these inhibitors on the rate of GluA1 channel opening and the amplitude of the glutamate-induced whole-cell current. We found that both compounds inhibit GluA1 channel noncompetitively. Addition of an N-3 methyl-Carbamoyl Group to the diazepine ring with the azomethine feature (i.e., GYKI 52466) improves the potency of the resulting compound or BDZ-f without changing the site of binding. This site, which we previously termed as the “M ” site on the GluA2 AMPA receptor subunit, therefore favorably accommodates an N-3 acylatin
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Mechanism of Inhibition of the GluA1 AMPA Receptor Channel Opening by the 2,3-Benzodiazepine Compound GYKI 52466 and a N‑Methyl-Carbamoyl Derivative
2015Co-Authors: Congzhou Wang, Li NiuAbstract:2,3-Benzodiazepine derivatives, also known as GYKI compounds, represent a Group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Here we investigate the mechanism of inhibition of the GluA1 channel opening and the site of inhibition by GYKI 52466 and its N-3 methyl-Carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the brain function. Excessive activity and elevated expression of GluA1, however, has been implicated in a number of neurological disorders. Using a laser-pulse photolysis technique, which provides ∼60 μs resolution, we measured the effect of these inhibitors on the rate of GluA1 channel opening and the amplitude of the glutamate-induced whole-cell current. We found that both compounds inhibit GluA1 channel noncompetitively. Addition of an N-3 methyl-Carbamoyl Group to the diazepine ring with the azomethine feature (i.e., GYKI 52466) improves the potency of the resulting compound or BDZ-f without changing the site of binding. This site, which we previously termed as the “M” site on the GluA2 AMPA receptor subunit, therefore favorably accommodates an N-3 acylating Group. On the basis of the magnitude of the inhibition constants for the same inhibitors but different receptors, the “M” sites on GluA1 and GuA2 are different. Overall, the “M” site or the binding environment on GluA2 accommodates the same compounds better, or the same inhibitors show stronger potency on GluA2, as we have reported previously [Wang et al. Biochemistry (2011) 50, 7284−7293]. However, acylating the N-3 position to occupy the N-3 side pocket of the “M” site can significantly narrow the difference and improve the potency of a resulting compound on GluA1
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mechanism of inhibition of the glua1 ampa receptor channel opening by the 2 3 benzodiazepine compound gyki 52466 and a n methyl Carbamoyl derivative
Biochemistry, 2014Co-Authors: Congzhou Wang, Li NiuAbstract:2,3-Benzodiazepine derivatives, also known as GYKI compounds, represent a Group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Here we investigate the mechanism of inhibition of the GluA1 channel opening and the site of inhibition by GYKI 52466 and its N-3 methyl-Carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the brain function. Excessive activity and elevated expression of GluA1, however, has been implicated in a number of neurological disorders. Using a laser-pulse photolysis technique, which provides ∼60 μs resolution, we measured the effect of these inhibitors on the rate of GluA1 channel opening and the amplitude of the glutamate-induced whole-cell current. We found that both compounds inhibit GluA1 channel noncompetitively. Addition of an N-3 methyl-Carbamoyl Group to the diazepine ring with the azomethine feature (i.e., GYKI 52466) improves the potency of the resulting compound or BDZ-f without changing the site of binding. This site, which we previously termed as the “M” site on the GluA2 AMPA receptor subunit, therefore favorably accommodates an N-3 acylating Group. On the basis of the magnitude of the inhibition constants for the same inhibitors but different receptors, the “M” sites on GluA1 and GuA2 are different. Overall, the “M” site or the binding environment on GluA2 accommodates the same compounds better, or the same inhibitors show stronger potency on GluA2, as we have reported previously [Wang et al. Biochemistry (2011) 50, 7284−7293]. However, acylating the N-3 position to occupy the N-3 side pocket of the “M” site can significantly narrow the difference and improve the potency of a resulting compound on GluA1.
Yoshihisa Ozoe - One of the best experts on this subject based on the ideXlab platform.
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4 5 substituted 3 isoxazolols with insecticidal activity act as competitive antagonists of housefly gaba receptors
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Genyan Liu, Fumiyo Ozoe, Kenjiro Furuta, Yoshihisa OzoeAbstract:The insect GABA receptor (GABAR), which is composed of five RDL subunits, represents an important target for insecticides. A series of 4,5-disubstituted 3-isoxazolols, including muscimol analogues, were synthesized and examined for their activities against four splice variants (ac, ad, bc, and bd) of housefly GABARs expressed in Xenopus oocytes. Muscimol was a more potent agonist than GABA in all four splice variants, whereas synthesized analogues did not exhibit agonism but rather antagonism in housefly GABARs. The introduction of bicyclic aromatic Groups at the 4-position of muscimol and the simultaneous replacement of the aminomethyl Group with a Carbamoyl Group at the 5-position to afford six 4-aryl-5-Carbamoyl-3-isoxazolols resulted in compounds that exhibited significantly enhanced antagonism with IC50 values in the low micromolar range in the ac variant. The inhibition of GABA-induced currents by 100 μM analogues was approximately 1.5–4-fold greater in the ac and bc variants than in the ad and bd v...
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4,5-Substituted 3‑Isoxazolols with Insecticidal Activity Act as Competitive Antagonists of Housefly GABA Receptors
2015Co-Authors: Genyan Liu, Fumiyo Ozoe, Kenjiro Furuta, Yoshihisa OzoeAbstract:The insect GABA receptor (GABAR), which is composed of five RDL subunits, represents an important target for insecticides. A series of 4,5-disubstituted 3-isoxazolols, including muscimol analogues, were synthesized and examined for their activities against four splice variants (ac, ad, bc, and bd) of housefly GABARs expressed in Xenopus oocytes. Muscimol was a more potent agonist than GABA in all four splice variants, whereas synthesized analogues did not exhibit agonism but rather antagonism in housefly GABARs. The introduction of bicyclic aromatic Groups at the 4-position of muscimol and the simultaneous replacement of the aminomethyl Group with a Carbamoyl Group at the 5-position to afford six 4-aryl-5-Carbamoyl-3-isoxazolols resulted in compounds that exhibited significantly enhanced antagonism with IC50 values in the low micromolar range in the ac variant. The inhibition of GABA-induced currents by 100 μM analogues was approximately 1.5–4-fold greater in the ac and bc variants than in the ad and bd variants. 4-(3-Biphenylyl)-5-Carbamoyl-3-isoxazolol displayed competitive antagonism, with IC50 values of 30, 34, 107, and 96 μM in the ac, bc, ad, and bd variants, respectively, and exhibited moderate insecticidal activity against houseflies, with an LD50 value of 5.6 nmol/fly. These findings suggest that these 3-isoxazolol analogues are novel lead compounds for the design and development of insecticides that target the orthosteric site of housefly GABARs
Congzhou Wang - One of the best experts on this subject based on the ideXlab platform.
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Mechanism of inhibition of the GluA1 AMPA receptor channel opening by the 2, 3-benzodiazepine compound GYKI 52466 and a N-methyl-Carbamoyl derivative. Biochemistry 2014;53:3033–41
2016Co-Authors: Congzhou Wang, Li NiuAbstract:ABSTRACT: 2,3-Benzodiazepine derivatives, also known as GYKI compounds, represent a Group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors. Here we investigate the mechanism of inhibition of the GluA1 channel opening and the site of inhibition by GYKI 52466 and its N-3 methyl-Carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the brain function. Excessive activity and elevated expression of GluA1, however, has been implicated in a number of neurological disorders. Using a laser-pulse photolysis technique, which provides ∼60 μs resolution, we measured the effect of these inhibitors on the rate of GluA1 channel opening and the amplitude of the glutamate-induced whole-cell current. We found that both compounds inhibit GluA1 channel noncompetitively. Addition of an N-3 methyl-Carbamoyl Group to the diazepine ring with the azomethine feature (i.e., GYKI 52466) improves the potency of the resulting compound or BDZ-f without changing the site of binding. This site, which we previously termed as the “M ” site on the GluA2 AMPA receptor subunit, therefore favorably accommodates an N-3 acylatin
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Mechanism of Inhibition of the GluA1 AMPA Receptor Channel Opening by the 2,3-Benzodiazepine Compound GYKI 52466 and a N‑Methyl-Carbamoyl Derivative
2015Co-Authors: Congzhou Wang, Li NiuAbstract:2,3-Benzodiazepine derivatives, also known as GYKI compounds, represent a Group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Here we investigate the mechanism of inhibition of the GluA1 channel opening and the site of inhibition by GYKI 52466 and its N-3 methyl-Carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the brain function. Excessive activity and elevated expression of GluA1, however, has been implicated in a number of neurological disorders. Using a laser-pulse photolysis technique, which provides ∼60 μs resolution, we measured the effect of these inhibitors on the rate of GluA1 channel opening and the amplitude of the glutamate-induced whole-cell current. We found that both compounds inhibit GluA1 channel noncompetitively. Addition of an N-3 methyl-Carbamoyl Group to the diazepine ring with the azomethine feature (i.e., GYKI 52466) improves the potency of the resulting compound or BDZ-f without changing the site of binding. This site, which we previously termed as the “M” site on the GluA2 AMPA receptor subunit, therefore favorably accommodates an N-3 acylating Group. On the basis of the magnitude of the inhibition constants for the same inhibitors but different receptors, the “M” sites on GluA1 and GuA2 are different. Overall, the “M” site or the binding environment on GluA2 accommodates the same compounds better, or the same inhibitors show stronger potency on GluA2, as we have reported previously [Wang et al. Biochemistry (2011) 50, 7284−7293]. However, acylating the N-3 position to occupy the N-3 side pocket of the “M” site can significantly narrow the difference and improve the potency of a resulting compound on GluA1
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mechanism of inhibition of the glua1 ampa receptor channel opening by the 2 3 benzodiazepine compound gyki 52466 and a n methyl Carbamoyl derivative
Biochemistry, 2014Co-Authors: Congzhou Wang, Li NiuAbstract:2,3-Benzodiazepine derivatives, also known as GYKI compounds, represent a Group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Here we investigate the mechanism of inhibition of the GluA1 channel opening and the site of inhibition by GYKI 52466 and its N-3 methyl-Carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the brain function. Excessive activity and elevated expression of GluA1, however, has been implicated in a number of neurological disorders. Using a laser-pulse photolysis technique, which provides ∼60 μs resolution, we measured the effect of these inhibitors on the rate of GluA1 channel opening and the amplitude of the glutamate-induced whole-cell current. We found that both compounds inhibit GluA1 channel noncompetitively. Addition of an N-3 methyl-Carbamoyl Group to the diazepine ring with the azomethine feature (i.e., GYKI 52466) improves the potency of the resulting compound or BDZ-f without changing the site of binding. This site, which we previously termed as the “M” site on the GluA2 AMPA receptor subunit, therefore favorably accommodates an N-3 acylating Group. On the basis of the magnitude of the inhibition constants for the same inhibitors but different receptors, the “M” sites on GluA1 and GuA2 are different. Overall, the “M” site or the binding environment on GluA2 accommodates the same compounds better, or the same inhibitors show stronger potency on GluA2, as we have reported previously [Wang et al. Biochemistry (2011) 50, 7284−7293]. However, acylating the N-3 position to occupy the N-3 side pocket of the “M” site can significantly narrow the difference and improve the potency of a resulting compound on GluA1.
Masayoshi Kawaguchi - One of the best experts on this subject based on the ideXlab platform.
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responses of a model legume lotus japonicus to lipochitin oligosaccharide nodulation factors purified from mesorhizobium loti jrl501
Molecular Plant-microbe Interactions, 2001Co-Authors: Shinobu Niwa, Haruko Imaizumianraku, Svetlana A Chechetka, Masumi Ishizaka, Akira Ikuta, Masayoshi Kawaguchi, Hiroshi KouchiAbstract:Lotus japonicus has been proposed as a model legume for molecular genetic studies of symbiotic plant-microbe interactions leading to the fixation of atmospheric nitrogen. Lipochitin oligosaccharides (LCOs), or Nod factors, were isolated from the culture of Mesorhizobium loti strain JRL501 (MAFF303099), an efficient microsymbiont of L. japonicus B-129 cv. Gifu. High-performance liquid chromatography and mass spectrometric analyses allowed us to identify at least five different structures of LCOs that were produced by JRL501. The major component was NodMl-V(C18:1, Me, Cb, AcFuc), an N-acetyl-glucosamine pentamer in which the nonreducing residue is N-acylated with a C18:1 acyl moiety, N-methylated, and carries a Carbamoyl Group and the reducing N-acetyl-glucosamine residue is substituted with 4-O-acetyl-fucose. Additional novel LCO structures bearing fucose instead of acetyl-fucose at the reducing end were identified. Mixtures of these LCOs could elicit abundant root hair deformation on L. japonicus roots at...
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responses of a model legume lotus japonicus to lipochitin oligosaccharide nodulation factors purified from mesorhizobium loti jrl501
Molecular Plant-microbe Interactions, 2001Co-Authors: Sinobu Niwa, Svetlana A Chechetka, Masumi Ishizaka, Akira Ikuta, Masayoshi Kawaguchi, H Imazumianraku, Hiroshi KouchiAbstract:Lotus japonicus has been proposed as a model legume for molecular genetic studies of symbiotic plant-microbe interactions leading to the fixation of atmospheric nitrogen. Lipochitin oligosaccharides (LCOs), or Nod factors, were isolated from the culture of Mesorhizobium loti strain JRL501 (MAFF303099), an efficient microsymbiont of L. japonicus B-129 cv. Gifu. High-performance liquid chromatography and mass spectrometric analyses allowed us to identify at least five different structures of LCOs that were produced by JRL501. The major component was NodMl-V(C18:1, Me, Cb, AcFuc), an N-acetyl-glucosamine pentamer in which the nonreducing residue is N-acylated with a C18:1 acyl moiety, N-methylated, and carries a Carbamoyl Group and the reducing N-acetylglucosamine residue is substituted with 4-O-acetyl-fucose. Additional novel LCO structures bearing fucose instead of acetyl-fucose at the reducing end were identified. Mixtures of these LCOs could elicit abundant root hair deformation on L. japonicus roots at a concentration of 10(-7) to 10(-9) M. Spot inoculation of a few nanograms of LCOs on L. japonicus roots induced the formation of nodule primordia in which the early nodulin genes, ENOD40 and ENOD2, were expressed in a tissue-specific manner. We also observed the formation of a cytoplasmic bridge (preinfection thread) in the swollen outermost cortical cells. This is the first description of cytoplasmic bridge formation by purified LCOs alone in a legume-forming determinate nodules.