The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform

Bernard R Glick - One of the best experts on this subject based on the ideXlab platform.

  • role of pseudomonas putida indoleacetic Acid in development of the host plant root system
    Applied and Environmental Microbiology, 2002
    Co-Authors: Cheryl L Patten, Bernard R Glick
    Abstract:

    Many plant-associated bacteria synthesize the phytohormone indoleacetic Acid (IAA). While IAA produced by phytopathogenic bacteria, mainly by the indoleacetamide pathway, has been implicated in the induction of plant tumors, it is not clear whether IAA synthesized by beneficial bacteria, usually via the Indolepyruvic Acid pathway, is involved in plant growth promotion. To determine whether bacterial IAA enhances root development in host plants, the ipdc gene that encodes indolepyruvate decarboxylase, a key enzyme in the Indolepyruvic Acid pathway, was isolated from the plant growth-promoting bacterium Pseudomonas putida GR12-2 and an IAA-deficient mutant constructed by insertional mutagenesis. The canola seedling primary roots from seeds treated with wild-type P. putida GR12-2 were on average 35 to 50% longer than the roots from seeds treated with the IAA-deficient mutant and the roots from uninoculated seeds. In addition, exposing mung bean cuttings to high levels of IAA by soaking them in a suspension of the wild-type strain stimulated the formation of many, very small, adventitious roots. Formation of fewer roots was stimulated by treatment with the IAA-deficient mutant. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

Cheryl L Patten - One of the best experts on this subject based on the ideXlab platform.

  • role of pseudomonas putida indoleacetic Acid in development of the host plant root system
    Applied and Environmental Microbiology, 2002
    Co-Authors: Cheryl L Patten, Bernard R Glick
    Abstract:

    Many plant-associated bacteria synthesize the phytohormone indoleacetic Acid (IAA). While IAA produced by phytopathogenic bacteria, mainly by the indoleacetamide pathway, has been implicated in the induction of plant tumors, it is not clear whether IAA synthesized by beneficial bacteria, usually via the Indolepyruvic Acid pathway, is involved in plant growth promotion. To determine whether bacterial IAA enhances root development in host plants, the ipdc gene that encodes indolepyruvate decarboxylase, a key enzyme in the Indolepyruvic Acid pathway, was isolated from the plant growth-promoting bacterium Pseudomonas putida GR12-2 and an IAA-deficient mutant constructed by insertional mutagenesis. The canola seedling primary roots from seeds treated with wild-type P. putida GR12-2 were on average 35 to 50% longer than the roots from seeds treated with the IAA-deficient mutant and the roots from uninoculated seeds. In addition, exposing mung bean cuttings to high levels of IAA by soaking them in a suspension of the wild-type strain stimulated the formation of many, very small, adventitious roots. Formation of fewer roots was stimulated by treatment with the IAA-deficient mutant. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

Steele J. L. - One of the best experts on this subject based on the ideXlab platform.

  • Aromatic amino Acid catabolism by lactococci
    Hosted by Utah State University Libraries, 1997
    Co-Authors: Gao S., Oh D. H., Broadbent, Jeffery R., Johnson M. E., Weimer B. C., Steele J. L.
    Abstract:

    While catabolism of amino Acids is believed to play an important role in cheese flavor development, the pathways present in cheese microflora are poorly understood. To determine the pathways of aromatic amino Acid catabolism in lactococci and effects of Cheddar cheese ripening conditions on catabolic enzymes and products, eight starter lactococcal strains were screened. Cell-free extracts prepared from these strains were found to contain an α-ketoglutarate-dependent aminotransferase activity with tryptophan, tyrosine and phenylalanine. Tryptophan, tyrosine and phenylalanine aminotransferase specific activities (μmol product formed / mg protein / min) ranged from 0.30 to 2.8 10-3, 0.93 to 7.3 10-3 and 1.5 to 7.2 10-3, respectively. Metabolites produced from tryptophan by a cell-free extract of Lactococcus lactis S3 were Indolepyruvic Acid, indoleacetic Acid and indole-3-aldehyde. Indoleacetic Acid and indole-3-aldehyde can form spontaneously from Indolepyruvic Acid under the conditions employed. A defined medium was used to determine whether the aminotransferase(s) was expressed and which metabolite(s) accumulate under conditions that simulated those of ripening Cheddar cheese in terms of pH, salt, temperature and carbohydrate starvation. The results indicated that the aminotransferase(s) was expressed and stable under these conditions. The tryptophan metabolites that accumulated were determined to be strain-specifïc

Gao S. - One of the best experts on this subject based on the ideXlab platform.

  • Aromatic amino Acid catabolism by lactococci
    Hosted by Utah State University Libraries, 1997
    Co-Authors: Gao S., Oh D. H., Broadbent, Jeffery R., Johnson M. E., Weimer B. C., Steele J. L.
    Abstract:

    While catabolism of amino Acids is believed to play an important role in cheese flavor development, the pathways present in cheese microflora are poorly understood. To determine the pathways of aromatic amino Acid catabolism in lactococci and effects of Cheddar cheese ripening conditions on catabolic enzymes and products, eight starter lactococcal strains were screened. Cell-free extracts prepared from these strains were found to contain an α-ketoglutarate-dependent aminotransferase activity with tryptophan, tyrosine and phenylalanine. Tryptophan, tyrosine and phenylalanine aminotransferase specific activities (μmol product formed / mg protein / min) ranged from 0.30 to 2.8 10-3, 0.93 to 7.3 10-3 and 1.5 to 7.2 10-3, respectively. Metabolites produced from tryptophan by a cell-free extract of Lactococcus lactis S3 were Indolepyruvic Acid, indoleacetic Acid and indole-3-aldehyde. Indoleacetic Acid and indole-3-aldehyde can form spontaneously from Indolepyruvic Acid under the conditions employed. A defined medium was used to determine whether the aminotransferase(s) was expressed and which metabolite(s) accumulate under conditions that simulated those of ripening Cheddar cheese in terms of pH, salt, temperature and carbohydrate starvation. The results indicated that the aminotransferase(s) was expressed and stable under these conditions. The tryptophan metabolites that accumulated were determined to be strain-specifïc

Oh D. H. - One of the best experts on this subject based on the ideXlab platform.

  • Aromatic amino Acid catabolism by lactococci
    Hosted by Utah State University Libraries, 1997
    Co-Authors: Gao S., Oh D. H., Broadbent, Jeffery R., Johnson M. E., Weimer B. C., Steele J. L.
    Abstract:

    While catabolism of amino Acids is believed to play an important role in cheese flavor development, the pathways present in cheese microflora are poorly understood. To determine the pathways of aromatic amino Acid catabolism in lactococci and effects of Cheddar cheese ripening conditions on catabolic enzymes and products, eight starter lactococcal strains were screened. Cell-free extracts prepared from these strains were found to contain an α-ketoglutarate-dependent aminotransferase activity with tryptophan, tyrosine and phenylalanine. Tryptophan, tyrosine and phenylalanine aminotransferase specific activities (μmol product formed / mg protein / min) ranged from 0.30 to 2.8 10-3, 0.93 to 7.3 10-3 and 1.5 to 7.2 10-3, respectively. Metabolites produced from tryptophan by a cell-free extract of Lactococcus lactis S3 were Indolepyruvic Acid, indoleacetic Acid and indole-3-aldehyde. Indoleacetic Acid and indole-3-aldehyde can form spontaneously from Indolepyruvic Acid under the conditions employed. A defined medium was used to determine whether the aminotransferase(s) was expressed and which metabolite(s) accumulate under conditions that simulated those of ripening Cheddar cheese in terms of pH, salt, temperature and carbohydrate starvation. The results indicated that the aminotransferase(s) was expressed and stable under these conditions. The tryptophan metabolites that accumulated were determined to be strain-specifïc