The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Thomas Leisinger - One of the best experts on this subject based on the ideXlab platform.

  • Microbial Metabolism of sulfurand phosphorus-containing xenobiotics
    Fems Microbiology Reviews, 1994
    Co-Authors: Michael A. Kertesz, Alasdair M. Cook, Thomas Leisinger
    Abstract:

    The enzymes involved in the Microbial Metabolism of many important phosphorus- or sulfur-containing xenobiotics, including organophosphate insecticides and precursors to organosulfate and organosulfonate detergents and dyestuffs have been characterized. In several instances their genes have been cloned and analysed. For phosphonate xenobiotics, the enzyme system responsible for the cleavage of the carbon-phosphorus bond has not yet been observed in vitro, though much is understood on a genetic level about phosphonate degradation. Phosphonate Metabolism is regulated as part of the Pho regulon, under phosphate starvation control. For organophosphorothionate pesticides the situation is not so clear, and the mode of regulation appears to depend on whether the compounds are utilized to provide phosphorus, carbon or sulfur for cell growth. The same is true for organosulfonate Metabolism, where different (and differently regulated) enzymatic pathways are involved in the utilization of sulfonates as carbon and as sulfur sources, respectively. Observations at the protein level in a number of bacteria suggest that a regulatory system is present which responds to sulfate limitation and controls the synthesis of proteins involved in providing sulfur to the cell and which may reveal analogies between the regulation of phosphorus and sulfur Metabolism.

  • Microbial Metabolism of sulfur- and phosphorus-containing xenobiotics.
    FEMS microbiology reviews, 1994
    Co-Authors: Michael A. Kertesz, Alasdair M. Cook, Thomas Leisinger
    Abstract:

    The enzymes involved in the Microbial Metabolism of many important phosphorus- or sulfur-containing xenobiotics, including organophosphate insecticides and precursors to organosulfate and organosulfonate detergents and dyestuffs have been characterized. In several instances their genes have been cloned and analysed. For phosphonate xenobiotics, the enzyme system responsible for the cleavage of the carbon-phosphorus bond has not yet been observed in vitro, though much is understood on a genetic level about phosphonate degradation. Phosphonate Metabolism is regulated as part of the Pho regulon, under phosphate starvation control. For organophosphorothionate pesticides the situation is not so clear, and the mode of regulation appears to depend on whether the compounds are utilized to provide phosphorus, carbon or sulfur for cell growth. The same is true for organosulfonate Metabolism, where different (and differently regulated) enzymatic pathways are involved in the utilization of sulfonates as carbon and as sulfur sources, respectively. Observations at the protein level in a number of bacteria suggest that a regulatory system is present which responds to sulfate limitation and controls the synthesis of proteins involved in providing sulfur to the cell and which may reveal analogies between the regulation of phosphorus and sulfur Metabolism.

Timothy R. Orchard - One of the best experts on this subject based on the ideXlab platform.

  • differences in gut Microbial Metabolism are responsible for reduced hippurate synthesis in crohn s disease
    BMC Gastroenterology, 2010
    Co-Authors: Horace R. T. Williams, Jeremy F L Cobbold, Sara E Marshall, Simon D Taylorrobinson, David G Walker, Timothy R. Orchard
    Abstract:

    Background Certain urinary metabolites are the product of gut Microbial or mammalian Metabolism; others, such as hippurate, are mammalian-Microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut Microbial Metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal conjugation of benzoate with glycine, forming hippurate. Differences in such urinary co-metabolites may therefore reflect systemic consequences of altered gut Microbial Metabolism, though altered host metabolic pathways may also be involved.

  • Differences in gut Microbial Metabolism are responsible for reduced hippurate synthesis in Crohn's disease
    BMC gastroenterology, 2010
    Co-Authors: Horace R. T. Williams, Jeremy F L Cobbold, Sara E Marshall, David G Walker, I. Jane Cox, Simon D. Taylor-robinson, Timothy R. Orchard
    Abstract:

    Certain urinary metabolites are the product of gut Microbial or mammalian Metabolism; others, such as hippurate, are mammalian-Microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut Microbial Metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal conjugation of benzoate with glycine, forming hippurate. Differences in such urinary co-metabolites may therefore reflect systemic consequences of altered gut Microbial Metabolism, though altered host metabolic pathways may also be involved. It was hypothesised that reduced hippurate excretion in CD patients was due to alterations in the gut microbiota, and not differences in dietary benzoate, nor defective host enzymatic conjugation of benzoate. 5 mg/kg sodium benzoate were administered orally to 16 CD patients and 16 healthy controls on a low-benzoate diet. Baseline and peak urinary hippurate excretion were measured. Baseline hippurate levels were significantly lower in the CD patients (p = 0.0009). After benzoate ingestion, peak urinary levels of hippurate did not differ significantly between the cohorts. Consequently the relative increase in excretion was significantly greater in CD (p = 0.0007). Lower urinary hippurate levels in CD are not due to differences in dietary benzoate. A defect in the enzymatic conjugation of benzoate in CD has been excluded, strongly implicating altered gut Microbial Metabolism as the cause of decreased hippurate levels in CD.

Michael A. Kertesz - One of the best experts on this subject based on the ideXlab platform.

  • Microbial Metabolism of sulfurand phosphorus-containing xenobiotics
    Fems Microbiology Reviews, 1994
    Co-Authors: Michael A. Kertesz, Alasdair M. Cook, Thomas Leisinger
    Abstract:

    The enzymes involved in the Microbial Metabolism of many important phosphorus- or sulfur-containing xenobiotics, including organophosphate insecticides and precursors to organosulfate and organosulfonate detergents and dyestuffs have been characterized. In several instances their genes have been cloned and analysed. For phosphonate xenobiotics, the enzyme system responsible for the cleavage of the carbon-phosphorus bond has not yet been observed in vitro, though much is understood on a genetic level about phosphonate degradation. Phosphonate Metabolism is regulated as part of the Pho regulon, under phosphate starvation control. For organophosphorothionate pesticides the situation is not so clear, and the mode of regulation appears to depend on whether the compounds are utilized to provide phosphorus, carbon or sulfur for cell growth. The same is true for organosulfonate Metabolism, where different (and differently regulated) enzymatic pathways are involved in the utilization of sulfonates as carbon and as sulfur sources, respectively. Observations at the protein level in a number of bacteria suggest that a regulatory system is present which responds to sulfate limitation and controls the synthesis of proteins involved in providing sulfur to the cell and which may reveal analogies between the regulation of phosphorus and sulfur Metabolism.

  • Microbial Metabolism of sulfur- and phosphorus-containing xenobiotics.
    FEMS microbiology reviews, 1994
    Co-Authors: Michael A. Kertesz, Alasdair M. Cook, Thomas Leisinger
    Abstract:

    The enzymes involved in the Microbial Metabolism of many important phosphorus- or sulfur-containing xenobiotics, including organophosphate insecticides and precursors to organosulfate and organosulfonate detergents and dyestuffs have been characterized. In several instances their genes have been cloned and analysed. For phosphonate xenobiotics, the enzyme system responsible for the cleavage of the carbon-phosphorus bond has not yet been observed in vitro, though much is understood on a genetic level about phosphonate degradation. Phosphonate Metabolism is regulated as part of the Pho regulon, under phosphate starvation control. For organophosphorothionate pesticides the situation is not so clear, and the mode of regulation appears to depend on whether the compounds are utilized to provide phosphorus, carbon or sulfur for cell growth. The same is true for organosulfonate Metabolism, where different (and differently regulated) enzymatic pathways are involved in the utilization of sulfonates as carbon and as sulfur sources, respectively. Observations at the protein level in a number of bacteria suggest that a regulatory system is present which responds to sulfate limitation and controls the synthesis of proteins involved in providing sulfur to the cell and which may reveal analogies between the regulation of phosphorus and sulfur Metabolism.

Horace R. T. Williams - One of the best experts on this subject based on the ideXlab platform.

  • differences in gut Microbial Metabolism are responsible for reduced hippurate synthesis in crohn s disease
    BMC Gastroenterology, 2010
    Co-Authors: Horace R. T. Williams, Jeremy F L Cobbold, Sara E Marshall, Simon D Taylorrobinson, David G Walker, Timothy R. Orchard
    Abstract:

    Background Certain urinary metabolites are the product of gut Microbial or mammalian Metabolism; others, such as hippurate, are mammalian-Microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut Microbial Metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal conjugation of benzoate with glycine, forming hippurate. Differences in such urinary co-metabolites may therefore reflect systemic consequences of altered gut Microbial Metabolism, though altered host metabolic pathways may also be involved.

  • Differences in gut Microbial Metabolism are responsible for reduced hippurate synthesis in Crohn's disease
    BMC gastroenterology, 2010
    Co-Authors: Horace R. T. Williams, Jeremy F L Cobbold, Sara E Marshall, David G Walker, I. Jane Cox, Simon D. Taylor-robinson, Timothy R. Orchard
    Abstract:

    Certain urinary metabolites are the product of gut Microbial or mammalian Metabolism; others, such as hippurate, are mammalian-Microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut Microbial Metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal conjugation of benzoate with glycine, forming hippurate. Differences in such urinary co-metabolites may therefore reflect systemic consequences of altered gut Microbial Metabolism, though altered host metabolic pathways may also be involved. It was hypothesised that reduced hippurate excretion in CD patients was due to alterations in the gut microbiota, and not differences in dietary benzoate, nor defective host enzymatic conjugation of benzoate. 5 mg/kg sodium benzoate were administered orally to 16 CD patients and 16 healthy controls on a low-benzoate diet. Baseline and peak urinary hippurate excretion were measured. Baseline hippurate levels were significantly lower in the CD patients (p = 0.0009). After benzoate ingestion, peak urinary levels of hippurate did not differ significantly between the cohorts. Consequently the relative increase in excretion was significantly greater in CD (p = 0.0007). Lower urinary hippurate levels in CD are not due to differences in dietary benzoate. A defect in the enzymatic conjugation of benzoate in CD has been excluded, strongly implicating altered gut Microbial Metabolism as the cause of decreased hippurate levels in CD.

Alasdair M. Cook - One of the best experts on this subject based on the ideXlab platform.

  • Microbial Metabolism of sulfurand phosphorus-containing xenobiotics
    Fems Microbiology Reviews, 1994
    Co-Authors: Michael A. Kertesz, Alasdair M. Cook, Thomas Leisinger
    Abstract:

    The enzymes involved in the Microbial Metabolism of many important phosphorus- or sulfur-containing xenobiotics, including organophosphate insecticides and precursors to organosulfate and organosulfonate detergents and dyestuffs have been characterized. In several instances their genes have been cloned and analysed. For phosphonate xenobiotics, the enzyme system responsible for the cleavage of the carbon-phosphorus bond has not yet been observed in vitro, though much is understood on a genetic level about phosphonate degradation. Phosphonate Metabolism is regulated as part of the Pho regulon, under phosphate starvation control. For organophosphorothionate pesticides the situation is not so clear, and the mode of regulation appears to depend on whether the compounds are utilized to provide phosphorus, carbon or sulfur for cell growth. The same is true for organosulfonate Metabolism, where different (and differently regulated) enzymatic pathways are involved in the utilization of sulfonates as carbon and as sulfur sources, respectively. Observations at the protein level in a number of bacteria suggest that a regulatory system is present which responds to sulfate limitation and controls the synthesis of proteins involved in providing sulfur to the cell and which may reveal analogies between the regulation of phosphorus and sulfur Metabolism.

  • Microbial Metabolism of sulfur- and phosphorus-containing xenobiotics.
    FEMS microbiology reviews, 1994
    Co-Authors: Michael A. Kertesz, Alasdair M. Cook, Thomas Leisinger
    Abstract:

    The enzymes involved in the Microbial Metabolism of many important phosphorus- or sulfur-containing xenobiotics, including organophosphate insecticides and precursors to organosulfate and organosulfonate detergents and dyestuffs have been characterized. In several instances their genes have been cloned and analysed. For phosphonate xenobiotics, the enzyme system responsible for the cleavage of the carbon-phosphorus bond has not yet been observed in vitro, though much is understood on a genetic level about phosphonate degradation. Phosphonate Metabolism is regulated as part of the Pho regulon, under phosphate starvation control. For organophosphorothionate pesticides the situation is not so clear, and the mode of regulation appears to depend on whether the compounds are utilized to provide phosphorus, carbon or sulfur for cell growth. The same is true for organosulfonate Metabolism, where different (and differently regulated) enzymatic pathways are involved in the utilization of sulfonates as carbon and as sulfur sources, respectively. Observations at the protein level in a number of bacteria suggest that a regulatory system is present which responds to sulfate limitation and controls the synthesis of proteins involved in providing sulfur to the cell and which may reveal analogies between the regulation of phosphorus and sulfur Metabolism.