• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.257-262
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• 1992

Virginiae butanolide (VB) is an autoregulator which triggers virginiamycin production in Strefltomyces virginiae. VB-C binding protein activity was investigated under various additives. The VB-C binding protein was almost fully observed in sotubte fraction (>90%) and the binding activity was optimum at pH 7.0. The VB-C binding activity was increased about 15% in 0.5 M KCI, whereas decreased about 60% in 20 mM $Mo^{6+}$. Chelating reagents (ethylenediarnine tetraacetic acid, ethyleneglycol bis(2-aminoethylether) tetraacetic acid, 8-hydroxyquinoline) and SH protecting reagents (rnercaptoethanol, dithiothreitol, thioglycerol) inhibited the VB-C binding activity about 30~55% and 3~20%, respectively. Serine protease inhibitor (phenyl methane sulfonyl fluoride), nucleotides (guanosine 5'-monophosphate, adenosine 3',5'-cyclic monophosphate), and phosphatases (alkaline, acid phosphatase) increased the VB-C binding activity about 17%, 6~20%, and 4- 13%, respectively.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.111-117
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• 1997

Streptomyces virginiae produces a set of autoregulators termed virginiae butanolide A-E(VB-A-E) which trigger virginiamycin production, and possesses a high-affinity virginiae butanolide receptor. To elucidate the functions of VB-C and VB-C receptor, we isolated two mutants from S. virginiae by N-methyl-N'-nitro-N-nitrosoguanidine and hydroxylamine. The characteristics of the mutants showed that the producing time of antibiotics was very delayed due to a slower production of VB-C receptor than that of VB. In S. ostreogriseus(VB', receptor -) and S. graminofaciens(VBU, receptor+), which produce the virginiamycin, the addition of synthetic VB-C repressed the production of antibiotics in S. ostreogriseus but induced tbe production in S. graminofaciens. HPLC analysis of S. graminofaciens suggested that the VB-C might have an ability to induce the production of virginiamycin and other antibiotics. These results imply that the VB-C has an ability to trigger the production of other secondary metabolites as well as virginiamycin under VB-C receptor existence.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.459-466
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• 1994

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the production of virginiamycin in Streptomyces virginiae. Streptomyces longwoodensis was selected as a test strain to investigate new VB-C functions. When 100 ng/ml of the synthetic VB-C was added into the culture at 5 hour and 0 hour, the initial production time of antibiotics and a dark blue pigment were shortened by 4~6 hours and 2~4 hours, respectively. HPLC analysis revealed the production of several new antibiotics by VB-C addition. In the SDS-PAGE analysis of the total protein from mycelium several new protein bands showed up and the amounts of certain protein bands increased in the presense of VB-C. The existence of specific VB-C binding protein was confirmed from S. longwoodensis in relation to VB-C signal transduction. These results suggest that the VB-C might have an ability to induce the production of secondary metabolites in Streptomy- ces longwoodensis.

• Korean Journal of Microbiology
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• v.30 no.3
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• pp.181-186
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• 1992

Virginiae butanolide C (VB-C) binding protein binds to virginiamycin inducing factor and the protein may function as a possible pleiotropic signal transducer. To further understand signal transducing mechanism, some properties of VB-C binding protcin were investigated. VB-C binding activity was gradually increased during 60 hrs incubation: whereas the amount of produced VBs was not changed. However. VB-C hinding activity was decreased by 30-5096 in the presence of genome DNA. The binding protein could he phosphorylated by [$\gamma-^{32}\textrm{P}$] ATP. These results suggest that the DNA binding and phosphorylation may be involved in signal transducing mechanism.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.59-66
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• 1996

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the productin of virginiamycin in Streptomyces virginiae. To further understand the mechanism of virginiamycin induction, we isolated three mutants from S. virginiae by N-methyl-N'-nitrosoguanidine (NTG) treatment. The characteristics of the three mutants were confirmed as follows: the mutant No. 1 delayed the production of the VB-C, receptor and antibiotics; the mutant No.3 hyperproduced receptor; the mutant No.4 failed to produce the VB-C. The addition of synthetic VB-C couldn't induce the production of antibiotics in the mutant No.1 due to delayed production of receptor, could provoke the production of larger amount of antibiotics than parental wild type strain in the mutant No.3 due to the presence of large amount of receptor, and could induce production of very small amount of antibiotics in the mutant No.4 due to the absence of VB-C. Antimicrobial spectrum and HPLC analysis of the mutant No.1 and No.3 suggested that the VB-C might have a specific ability to induce the production of virginiamycin M and S. These results imply that the VB-C has an ability to trigger the production of virginiamycin under receptor existence in S. virginiae.

• KSBB Journal
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• v.14 no.6
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• pp.682-687
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• 1999

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the production of virginiamycin in Streptomyces virginiae. In order to investigate the function of VB-C as inducer in other strains, Streptomyces erythraeus was used as a test strain(parent). VB-C binding receptor gene was introduced into S. erythraeus(transformant) and the production of VBs and specific VB-C binding protein were analysed in parent and transformant. When 300ng/ml of the synthetic VB-C was added at 0, 20, 44 h cultivation of the parent and at 44 h cultivation of the transformant, the initial production times a antibiotics were shortened by more than 8 and 6 h, respectively. The transformant showed strong antibiotic activity against B. subtilis. These results suggest that the VB-C might have an ability to induce the production of secondary metabolites in S. erythraeus.