• Title, Summary, Keyword: B. subtilis

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Comparison of the ${\sigma}^B$-Dependent General Stress Response between Bacillus subtilis and Listeria monocytogenes (Bacillus subtilis와 Listeria monocytogenes의 일반 스트레스반응의 비교)

  • Shin, Ji-Hyun
    • Korean Journal of Microbiology
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    • v.45 no.1
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    • pp.10-16
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    • 2009
  • A diverse range of stresses such as heat, cold, salt, ethanol, oxygen starvation or nutrient starvation induces same stress-responsive proteins. This general stress response enhances bacterial survival significantly. In Bacillus subtilis and closely related Gram-positive bacteria Listeria monocytogenes, the general stress response is controlled by the alternative transcription factor ${\sigma}^B$. The activity of ${\sigma}^B$ is regulated post-translationally by a signal transduction network that has been extensively studied in B. subtilis, and serve as a model for L. monocytogenes. The proposed model of L. monocytogenes signal transduction network is similar to that of B. subtilis, but the energy stress pathway is missing. More than 150 general stress proteins belong to ${\sigma}^B$ regulon of B. subtilis and L. monocytogenes. In both bacteria, ${\sigma}^B$ function is primarily important for resistance to diverse stresses. In addition, ${\sigma}^B$ function contributes to the control of important virulence genes in food-borne pathogen L. monocytogenes. Therefore, understanding of the general stress response is important not only for bacterial physiology, but also for pathogenicity.

Optimization of Staphylokinase Production in Bacillus subtilis Using Inducible and Constitutive Promoters

  • Kim, June-Hyung;Wong, Sui-Lam;Kim, Byung-Gee
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.3
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    • pp.167-172
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    • 2001
  • Staphylokinase (SAK) was produced in B. subtilis using two different promoter systems, i.e. the P43 and sacB promoters. To maximize SAK expression in B. subtilis, fermentation control strategies for each promoter were examined. SAK, under P43, a vegetative promoter transcribed mainly by $\sigma$(sup)B containing RNA polymerase, was overexpressed at low dissolved oxygen (D.O.) levels, suggesting that the sigB operon is somewhat affected by the energy charge of the cells. The expression of SAK at the 10% D.O. level was three times higher than that at the 50% D.O. level. In the case of sacB, a sucrose-inducible promoter, sucrose feeding was used to control the induction period and induction strength. Since sucrose is hydrolyzed by two sucrose hydrolyzing enzymes in the cell and culture broth, the control strategy was based on replenishing the loss of sucrose in the culture. With continuous feeding of sucrose, WB700 (pSAKBQ), which contains the SAK gene under sacB promoter, yielded ca. 35% more SAK than the batch culture. These results present efficient promoter-dependent control strategies in B. subtilis host system for foreign protein expression.

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Enzymatic Properties of Cytidine Deaminase Encoded by cdd Gene in Bacillus subtilis (Bacillus subtilis의 cdd 유전자에 의해 코드되는 Cytidine Deaminase의 효소학적 성질)

  • Song, Bang-Ho;Yoon, Mi-Sook;Kim, Kyung-Hwa;Yeo, Jeung-Sook;Jan Neuhard
    • Microbiology and Biotechnology Letters
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    • v.16 no.6
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    • pp.468-475
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    • 1988
  • The cloned B. subtilis cdd gene encoding cytidine/2'deoxycytidine deaminase (EC 3.5.4.5) was expressed in the cdd deficient B. subtilis mutant ED40. The gene was isolted from the cdd complementing plasmid pSO21, and inserted into the EcoR1/Pvu1 sites of pGB215-110 ΔB, which is a temperature sensitivie E. coli-B. subtilis shuttle vector. In the transformed B. subtilis ED4O harboring the resulting plasmid pSO100, cdd was expressed at several hundred fold elevated levels, and the cytidine deaminase activity in E. coli containing pSO100 was twice the level in B. subtilis/pSO0100. The Km value for cytidine of the partially purified enzyme is 1.88$\times$10$^{-4}$M at pH 7.0 and the V$_{max}$ = 11.1 $\mu$mol/min/mg of protein. The enzyme was completely inhibited by 0.1M mercaptoethanol and HgCl$_2$. The inhibition by p-chrolomercurybenzoic acid showed a Ki = 5 uM. These results suggest that sulfhydryl reagents block an active site thiol group, and/or disturb the formation of the tetrameic holoenzyme.

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The Antimicrobial Activity of Cheonggukjang, Using the New Strain, Bacilllus amyloliquefaciens NBF11-1 Extract and Their Heat and pH Stabilities (신균주 Bacillus amyloliquefaciens NBF11-1을 이용한 청국장의 항균활성과 열 및 pH 안정성)

  • Kim, Han Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.442-450
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    • 2016
  • This study aims to determine the antimicrobial activity of fermented Cheonggukjang extract using the new Strain, Bacillus amyloliquefaciens NBF11-1, which was first found on the surface of the node part of bamboo stems, but has been studied very little so far. Bacillus subtilis NG24, which is the traditional fermented strain of Cheonggukjang, was selected as the control group and a comparative analysis was performed. The experimental method included measurements of the antimicrobial activity, minimum inhibitory concentration (MIC) and heat and pH stability. B. amyloliquefaciens NBF11-1 had stronger antimicrobial activity than B. subtilis NG24 against the gram-positive bacteria, C. perfringens and S. aureus and the gram-negative bacteria, A. faecalis and E. coli among the six species of pathogenic bacteria studied. When the minimum inhibitory concentration was measured, B. amyloliquefaciens NBF11-1 in C. perfringens, S. aureus, A. faecalis, and E. coli had an inhibitory effect at concentrations of 0.01 %, 0.21 %, 0.45 % and 0.29 %, respectively, compared to B. subtilis NG24. When the heat and pH stability was measured, B. subtilis NG24 and B. amyloliquefaciens NBF11-1 Cheonggukjang extract did not show any decrease in activity when held at a temperature of $121^{\circ}C$ for 15 minutes and at pH values ranging from 2 to 10 and were therefore considered to be relatively stable against heat and pH changes.

Control Effect of Bacillus subtilis B-4228 on Root Rot of Panax ginseng (Bacillus subtilis B-4228의 인삼 근부병 억제효과)

  • Lee, Byung-Dae;Park, Hoon
    • Journal of Ginseng Research
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    • v.28 no.1
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    • pp.67-70
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    • 2004
  • Bacillus subtilis B-4228 selected from ginseng field soil for prevention of rusty root was tested for the control of ginseng root rot. In petri-plate dual culture, mycelial growth of Cylindrocarpon destructans was inhibited by B-4228 and hyphal swelling of C. destructans was occurred. In pot experiment with C. destructans-contaminated soil B-4228 dipping of ginseng seedling showed significant preventive effect of root rot (p=0.01), percent healthy root 82% and 20% for treatment and control, root rot rate 6% and 50.4%, respectively.

An Unusual Bioconjugate of Glycerol and Poly(${\gamma}$-Glutamic Acid) Produced by Bacillus subtilis C1

  • SHIH ING-LUNG;WU JANE-YII;WU PEI-JEN;SHEN MING-HAU
    • Journal of Microbiology and Biotechnology
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    • v.15 no.5
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    • pp.919-923
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    • 2005
  • A bacterium capable of poly(${\gamma}$-glutamic acid) production was isolated from nonpasteurized soy sauce. It was judged to be a variety of Bacillus subtilis and designated as B. subtilis C1. B. subtilis C1 produced ${\gamma}$-PGA in the absence of exogenous glutamic acid; therefore, it is a de novo PGA­producing bacterium. The product produced by B. subtilis C1 was characterized by amino acid analysis to be composed of solely glutamic acid. However, the $H^1-NMR$ spectra showed chemical shifts of glycerol protons in addition to those of authentic ${\gamma}$-PGA, indicating that the product is in fact a bioconjugate of ${\gamma}$-PGA. The finding is unique, because the microbial production of ${\gamma}$-PGA bioconjugate has never been reported before. The molecular mass of the product was over 10,000 kDa as determined by GPC, and $97\%$ of the product was D-glutamate, indicating that L-glutamate was converted to its D-form counterpart by B. subtilis C1.

Rhizosphere Inhibition of Cucumber Fusarium Wilt by Different Surfactinexcreting Strains of Bacillus subtilis

  • Jia, Ke;Gao, Yu-Han;Huang, Xiao-Qin;Guo, Rong-Jun;Li, Shi-Dong
    • The Plant Pathology Journal
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    • v.31 no.2
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    • pp.140-151
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    • 2015
  • Bacillus subtilis B006 strain effectively suppresses the cucumber fusarium wilt caused by Fusarium oxysporum f. sp. cucumerinum (Foc). The population dynamics of Foc, strain B006 and its surfactin over-producing mutant B841 and surfactin-deficient mutant B1020, in the rhizosphere were determined under greenhouse conditions to elucidate the importance of the lipopeptides excreted by these strains in suppressing Foc. Results showed that B. subtilis strain B006 effectively suppressed the disease in natural soil by 42.9%, five weeks after transplanting, whereas B841 and B1020 suppressed the disease by only 22.6% and 7.1%, respectively. Quantitative PCR assays showed that effective colonization of strain B006 in the rhizosphere suppressed Foc propagation by more than 10 times both in nursery substrate and in field-infected soil. Reduction of Foc population at the cucumber stems in a range of $0.96log_{10}ng/g$ to $2.39log_{10}ng/g$ was attained at the third and the fifth weeks of B006 treatment in nursery substrate. In field-infected soil, all three treatments with B. subtilis suppressed Foc infection, indicated by the reduction of Foc population at a range of $2.91log_{10}ng/g$ to $3.36log_{10}ng/g$ at the stem base, one week after transplanting. This study reveals that the suppression of fusarium wilt disease is affected by the effective colonization of the surfactin-producing B. subtilis strain in the rhizosphere. These results improved our understanding of the biocontrol mechanism of the B. subtilis strain B006 in the natural soil and facilitate its application as biocontrol agent in the field.

Characterization of Bacteriocin from Bacillus subtilis cx 1 (Bacillus subtilis cx1이 생산하는 박테리오신의 특성)

  • 김수인;장지윤;김인철;장해춘
    • Microbiology and Biotechnology Letters
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    • v.29 no.1
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    • pp.50-55
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    • 2001
  • A new bacteriocin produced by Bacillus subtilis cx1, was partially purified and characterized. The bactericoin from B. subtilis cx1 was stable in the range of pH 2.5-9.5. B. subtilis csx1 retained its antimicrobial activity to long-term exposure at $-20^{\circ}C$ and $-70^{\circ}C$. However, B. subtilis cx1 was inactivated completely within 15 min over $60^{\circ}C$ and lost 50% of its antimicrobial activity within 15 min at $50^{\circ}C$, B. subtilis cx1 was inactivated by protease, trypsin, proteinase K and carboxypeptidase, which indi-cates its protein nature. Direct detection of the antimicrobial activity on Tricine -SDS-PAGE suggested an apparent molecular mass of about 9,500 dalton.

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Genetic Transfer of Bacillus pasteurii Urease Gene into Antagonistic Bacillus subtilis YBL-7 against Root Rotting Fungi Fusarium solani (Bacillus parteurii Urease Gene의 생물방제균 Bacillus subtilis YBL-7내에서의 발현)

  • 김용수;김상달
    • Microbiology and Biotechnology Letters
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    • v.19 no.4
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    • pp.356-361
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    • 1991
  • - To investigate the possibility of genetic development for a multi-purpose strain of Bacillus subtilis YBL-7 against Fusat-iurn solani causing root rot of many impotant corps, the plasmid pGU66 inserting urease gene of Bacillus pasteurii had been introduced into Bacillus subtilis YBL-7 by PEG-induced protoplast (PIP) transformation system. Protoplasts of B. subtilis YBL-7 were prepared by treating the cells with lysozyme (200 $\mu g$/ml) in hypertonic buffer (SMMP). The highest transformation frequency was achieved when cells of the strain with lysozyme at $42^{\circ}C$ for 90 minutes. Optimal transformation was obtained using polyethylene glycol (MW 4000) at final concentration of 30% (V/V). The transformation frequency was increased proportionally to 1.2 $\mu g$ of plasmid DNA. At best condition, the transformation frequency (transformants/ regenerants/$\mu g$ of DNA) for pGU66 was appoximately $4 \times 10^{-3}$. Also, the urease gene was strongly expressed in the transformants of B. subtilis YBL-7 and maintained steadily. The antifungal ability of transformant was very similar to that of B. ssubtilis YBL-7.

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Isolation of a Potent Protease Producing Bacillus subtilis from Kimchi (김치로부터 단백질 분해 효소활성이 우수한 Bacillus subtilis 균주의 분리)

  • Choi, Chan-Yeong;Kim, Myoung-Dong
    • Microbiology and Biotechnology Letters
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    • v.45 no.1
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    • pp.12-18
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    • 2017
  • Microbial strains exhibiting proteolytic activity were isolated from kimchi, one of traditional fermented foods in Korea. Eight strains formed clear zones around their colonies when grown on TSA plates supplemented with skim milk. MBE/L865 exhibited 2.6-fold higher protease activity than that of control strain (Bacillus subtilis KCTC13112). MBE/L865 was identified as B. subtilis and deposited in the Korean Collection for Type Cultures under the accession number of KCCM43059. The optimum growth conditions for B. subtilis KCCM43059 were determined to be $37^{\circ}C$ and pH 8. The strain showed maximum protease activity ($429.37{\pm}18.65U/mg$ protein) at $60^{\circ}C$ and pH 6. Further, B. subtilis KCCM43059 had a higher salt (NaCl) tolerance than that of the control strain.