• The Korean Journal of Mycology
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• v.13 no.3
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• pp.141-148
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• 1985

To investigate cellular regulation of phosphate metabolism between catabolically repressed and derepressed states in Saccharomyces uvarum, the activities of polyphosphatases, the analysis of polyphosphate and cytochemical observation of volutin granules were examined according to the culture phase and under various phosphate concentrations. As the results, tripolyphosphatase activity was increased more than six-fold during catabolic repression as compared with those of catabolic derepression and the polyphosphatase activity increased at the time of maximal accumulation of acid insoluble polyphosphate 'B'. Of the low molecular weight polyphosphates, tripolyphosphate was mainly detected by thin layer chromatography. When the synthesis of volutin granules in derepressed cells was observed cytochemically, acid insoluble polyphosphate localizing at the cell wall was primarily synthesized and then transferred into the cytoplasm, nucleus and/or vacuole.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.99.1-100
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• 2003

E. intermedium Blocontrol activity of a P. chlororaphis rhizobacteium O6, depends to the synthesis of extracellular secondary metabolites and exoenzymes, thought to antagonize the pathogenicity of a variety of phytopathogenic fungi. The production of secondary metabolites and exoenzymes in O6, depends essentially on the GacS-mediated signal transduction pathway, which activates largely unknown signal transduction pathway. To exploit the GacS-mediated signal transdcution pathway involved in activation of ph genes that are necessary for biosynthesis of phenazine from P. chlororaphis O6, we cloned and sequenced the phz operon, rpoS gene encoding stationary specific sigma factor, ppx gene encoding polyphosphatase, and lon gene encoding ion protease. Expression of each gene in wild type and GacS mutant were analyzed by RT-PCR. Transcripts from rpoS, phzI enconing acylhomoserine lactone (AHL) synthase, and ph structural genes in the GacS mutant were reduced in each of these growth phases compared to the wild type. The GacS or Lon mutant was found to be deficient in the production of phenzines, exoenzymes, and the acylhomoserine lactone. These mutants were not complemented by ph operon and addition of exogenous AHL. These results indicate that the GacS global regulatory systems controls phenazine production at multiple levels. Future research will focus to identifying the GacS-mediated regulatory cascade involving in production of phenazine in P. chlororaphis.