Kun Sub Chung

Yonsei University, Seoul, Seoul, South Korea

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Publications (6)11.88 Total impact

  • Article: Culture-based and denaturing gradient gel electrophoresis analysis of the bacterial community from chungkookjang, a traditional korean fermented soybean food.
    Sung Wook Hong, Jae Young Choi, Kun Sub Chung
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    ABSTRACT: The bacterial community of Chungkookjang and raw rice-straw collected from various areas in South Korea was investigated using both culture-dependent and culture-independent methods. Pure cultures were isolated from Chungkookjang and raw rice-straw on tryptic soy agar plates with 72 to 121 colonies and identified by 16S rDNA gene sequence analysis, respectively. The traditional culture-based method and denaturing gradient gel electrophoresis analysis of PCR-amplified 16S rDNA confirmed that Pantoea agglomerans and B. subtilis were identified as predominant in the raw rice-straw and Chungkookjang, respectively, from Iljuk district of Gyeonggi province, P. ananatis and B. licheniformis were identified as predominant in the raw rice-straw and Chungkookjang from Wonju district of Gangwon province, and Microbacterium sp. and B. licheniformis were identified as predominant in the raw rice-straw and Chungkookjang from Sunchang district of Jeolla province. Other strains, such as Bacillus, Enterococcus, Pseudomonas, Rhodococcus, and uncultured bacteria were also present in raw rice-straw and Chungkookjang. Practical Application:  A comprehensive analysis of these microorganisms would provide a more detailed understanding of the biologically active components of Chungkookjang and help improve its quality. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis can be successfully applied to a fermented food to detect unculturable or more species than the culture-dependent method. This technique is an effective and convenient culture-independent method for studying the bacterial community in Chungkookjang. In this study, the bacterial community of Chungkookjang collected from various areas in South Korea was investigated using both culture-dependent and culture-independent methods.
    Journal of Food Science 09/2012; 77(10):M572-8. · 1.66 Impact Factor
  • Article: Bacillus eiseniae sp. nov., a swarming, moderately halotolerant bacterium isolated from the intestinal tract of an earthworm (Eisenia fetida L.).
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    ABSTRACT: A swarming and moderately halotolerant bacterium, designated strain A1-2(T), was isolated from the intestinal tract of the earthworm Eisenia fetida L. Cells were endospore-forming rods that were facultatively anaerobic, catalase-positive, oxidase-negative and motile by peritrichous flagella. The isolate grew optimally at 30 °C and pH 7.0, and could grow with up to 9 % (w/v) NaCl. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain A1-2(T) belonged to the genus Bacillus and exhibited 16S rRNA gene sequence similarities of 96.8, 96.0, 96.0, 96.4 and 96.7 % with Bacillus drentensis LMG 21831(T), B. horneckiae PT-45(T), B. niacini BAC 1015, B. infantis SMC 4352-1(T) and B. shackletonii LMG 18435(T), respectively. DNA-DNA relatedness values between the isolate and the reference strains were ≤38.3 %. The DNA G+C content of strain A1-2(T) was 38.5 mol%. The predominant menaquinone was MK-7 and the major polar lipids were diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were iso-C(15 : 0) (51.5 %) and anteiso-C(15 : 0) (29.6 %) and the cell-wall diamino acid was meso-diaminopimelic acid. On the basis of 16S rRNA gene sequence analysis and chemotaxonomic and phenotypic characteristics, it is concluded that strain A1-2(T) represents a novel species of the genus Bacillus, for which we propose the name Bacillus eiseniae sp. nov. The type strain is A1-2(T) ( = KCCM 90092(T) = JCM 16993(T)).
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 10/2011; 62(Pt 9):2077-83. · 2.11 Impact Factor
  • Article: Culture-based and denaturing gradient gel electrophoresis analysis of the bacterial community structure from the intestinal tracts of earthworms(Eisenia fetida).
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    ABSTRACT: The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and - independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culture-dependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms.
    Journal of Microbiology and Biotechnology 09/2011; 21(9):885-92. · 1.38 Impact Factor
  • Article: Polymerase chain reaction-denaturing gradient gel electrophoresis analysis of bacterial community structure in the food, intestines, and feces of earthworms.
    Sung Wook Hong, Ju Sam Lee, Kun Sub Chung
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    ABSTRACT: The bacterial communities in the food, intestines, and feces of earthworms were investigated by PCR-denaturing Gradient gel electrophoresis (DGGE). In this study, PCR-DGGE was optimized by testing 6 universal primer sets for microbial 16S rRNA in 6 pure culture strains of intestinal microbes in earthworms. One primer set effectively amplified 16S rRNA from bacterial populations that were found in the food, intestines, and feces of earthworms. Compared with the reference markers from the pure culture strains, the resulting DGGE profiles contained 28 unique DNA fragments. The dominant microorganisms in the food, intestines, and feces of earthworms included Rhodobacterales bacterium, Fusobacteria, Ferrimonas marina, Aeromonas popoffii, and soil bacteria. Other straisn, such as Acinetobacter, Clostridium, and Veillonella, as well as rumen bacteria and uncultured bacteria also were present. These results demonstrated that PCR-DGGE analysis can be used to elucidate bacterial diversity and identify unculturable microorganisms.
    The Journal of Microbiology 08/2011; 49(4):544-50. · 1.10 Impact Factor
  • Article: Effect of enzyme producing microorganisms on the biomass of epigeic earthworms (eisenia fetida) in vermicompost.
    Sung Wook Hong, Ju Sam Lee, Kun Sub Chung
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    ABSTRACT: We analyzed the bacterial community structure of the intestines of earthworms and determined the effect of enzyme producing microorganisms on the biomass of earthworms in vermicompost. Fifty-seven bacterial 16S rDNA clones were identified in the intestines of earthworms by using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Entomoplasma somnilux and Bacillus licheniformis were the dominant microorganisms; other strains included Aeromonas, Bacillus, Clostridium, Ferrimonas, and uncultured bacteria. Among these strains, Photobacterium ganghwense, Aeromonas hydrophila, and Paenibacillus motobuensis were enzyme-producing microorganisms. In the mixtures that were inoculated with pure cultures of A. hydrophila WA40 and P. motobuensis WN9, the highest survival rate was 100% and the average number of earthworms, young earthworms, and cocoons were 10, 4.00-4.33, and 3.00-3.33, respectively. In addition, P. motobuensis WN9 increased the growth of earthworms and production of casts in the vermicompost. These results show that earthworms and microorganisms have a symbiotic relationship.
    Bioresource technology 03/2011; 102(10):6344-7. · 4.25 Impact Factor
  • Article: Characteristics of B-cell-specific growth substance produced by Bacillus licheniformis E1.
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    ABSTRACT: A B cell-specific growth substance (BGS) was isolated from the slime layer of Bacillus licheniformis E1. Unlike LPS, the BGS was not affected by polymixin B, an inhibitor of LPS, or by TLR4, and resulted in the growth of B cells. When BALB/c mice were treated with the BGS, the B cell population was found to increase in both the bone marrow and the spleen, with a marked increase after 24 h in the bone marrow and after 48 h in the spleen. When using antibodies to B cell lineage-restricted surface molecules to analyze the B cell population changes resulting from treatment with the BGS, an increase in immature B cells (IgM(+) and AA4.1(+)) and mature B cells (IgM(+) and IgD(+)) was found in the bone marrow 24 h after treatment with the BGS, whereas a decrease in mature B cells and increase in IgG(+) B cells were found in the spleen. When the BGS and OVA antigen were injected into the peritoneal cavity of BALB/c mice, this resulted in a high OVA-specific antibody titer in the sera, similar to that induced by aluminum hydroxide. Therefore, it is anticipated that the mass production of the BGS by B. licheniformis E1 could be used for studies of B cells in immunology, and contribute to the development of a new adjuvant for vaccine manufacture.
    Journal of Microbiology and Biotechnology 02/2009; 19(1):55-64. · 1.38 Impact Factor