• Korean Journal of Microbiology
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• v.44 no.3
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• pp.237-243
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• 2008

Chemical and microbial characteristics of bacterial populations were investigated in a quercus and pine humus forest soil. Soil pH was $5.3\pm0.4$ and $4.1\pm0.9$ from each sample of a quercus and pine humus forest soil; C/N ratio of humus forest soil was $17.84\pm4.6%$ and $21.76\pm8%$, respectively. Total organic acid was investigated as 69.57 mM/g dry soil and 53.72 mM/g dry soil in each humus forest soil. Glutamine, pyruvate, succinate, lactic acid and acetic acid of pine humus forest soil were $1.5\sim4.5$ times higher than those of quercus humus forest soil. As we evaluated phylogenetic characteristics of bacterial populations by 16S rRNA-ARDRA analysis with DNA extracted from each humus forest soil. Based on the 16S rRNA sequences, 44 clone from ARDRA groups of quercus humus forest soil were classified into 7 phyla: ${\alpha},{\beta},{\gamma},{\delta}$-Proteobacteria, Acidobacteria, Actinobacteria, and Firmicutes. Thirty-two clone from ARDRA groups of pine humus forest soil were classified into 8 phyla: ${\alpha},{\beta},{\gamma}$-Proteobacteria, Acidobacteria, Bacteroides, Verrucomicrobia, Planctomycetes, and Gemmatomonadetes. According to PCA (Principal Component Analysis) based on 16S rRNA base sequence, there were three main groups of bacteria. All clone of Cluster I were originated from quercus humus forest soil, while 67% clone of Cluster II and 63% clone of Clusters III were separated from pine humus forest soil.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.994-1001
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• 2001

An easier way of understanding the BNR system was proposed from the study on substrate, nutrient removal tendency, microbial community and its metabolic function by applying the municipal settled sewage. During the anaerobic period, the phosphorus release rate per VFACOD we varied depending on the phosphorus content in the sludge. When the phosphorus content in the sludge was $6\%$ VSS, according to influent VFACOD, the phosphorus release rate and PHA production were $0.35 gPO_4P/gVFACOD$ and 1.0 gPHA/gVFACOD, respectively. The $NO_3N$ requirement for the phosphorus uptake as an electron acceptor was about $0.5 gNO_3N/gPO_4P_{uptake}$ based on the proposed equation with PHA, biomass, production, and the concentration of phosphorus release/uptake. Bacterial-community analysis of the sludge, as determined by FISH and 16SrDNA characterization FISH, revealed that the beta-subclass proteobacteria were the most abundant group ($27.9\%$ of the proteobacteria-specific probe EUB338), and it was likely that representative of the beta-subclass played key roles in activated sludge. The next dominant group found was the gamma-protebacteria ($15.4\%$ of probe EUB338). 16S rDNA clone library analysis showed that the members of${\beta}$- and ${\gamma}$-proteobacteria were also the most abundant groups, and $21.5\%$ (PN2 and PN4) and $15.4\%$ (PN1 and PN5) of total clones were the genera of denitrifying bacteria and PAO, respectively. Prediction of the microbial community composition was made with phosphorus content (Pv, $\%$ P/VSS) in wasted sludge and profiles of COD, PHA, $PO_4P,\;and\;NO_3N$ in an anaerobic-anoxic SBR unit. Generally, the predicted microbial composition based upon metabolic function, i.e., as measured by stoichiometry, is fairly similar to that measure by the unculturable dependent method. In this study, a proposal was made on he microbial community composition that was more easily approached to analyze the reactor behavior.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.293-299
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• 2005

Many isolates from soil of Korean ginseng rhizosphere did not show remarkable growth on full strength of the conventional nutrient broth (NB medium) but grew on its 100-fold dilution (DNB medium). Six hundred-forty strains were isolated as oligotrophic bacteria. In the course of screening for new bioactive compounds from oligotrophic bacteria from soil, 8 strains which had appeared to form of clear zone on a medium containing colloidal chitin as a sole carbon source were selected for further studies. Strain CR42 hydrolyzed a fluorogenic analogue of chitin, 4-methylumbelliferyl-D-glucosaminide (MUF-NAG) . Mo st of the culture supernatant of these isolates hydrolyzed 4-methylumbelliferyl-D-N,N'-diacetylchitobioside (MUF-diNAG). The isolates were heterogeneous and categorized to gamma- and beta-proteobacteria, Bacillaceae, Actinobactepia, and Bacteroides by 16S rRNA analysis. Two strains, WR164 and CR18, had a 16S rRNA sequence of $95-96\%$ identical to uncultured bacteria. It was observed that CR2 and CR75 could inhibit the growth of Colletotrichum gloeosporioides with hyphal extention-inhibition assay on PDA plate supplemented with $1\%$ colloidal chitin.

• Journal of Life Science
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• v.28 no.12
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• pp.1477-1488
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• 2018

This study investigated the muscles, intestines, and gonads of Sulculus diversicolor supertexta to examine the diversity of microbial communities within examples collected from the Jeju Coast. Using different media, initial pure isolation in MA, 1% BHIA, and 1% TSA indicated that the muscles, intestines, and gonads supported more communities, respectively. In analysis of relative similarity with 16s rRNA sequencing, 190 pure colonies were isolated, and further analysis with NBLAST identified 71 species, 39 genera, 25 families, and five phyla. Homogeny with the reference strain was 91-100%. Microbial communities in S. supertexta consisted of gamma and alpha Proteobacteria (48%), Actinobacteria (32.5%), Firmicutes (16.9%), Deinococcus-Thermus (1.3%), and Bacteroides (1.3%). In all tissue, Psychrobacter cibarius in Moraxellaceae was dominant. Alteromonadaceae, Enterobacteriaceae, Pasturellaceae, Moraxellaceae, Rhodobacteraceae, Geminicoccaceae, Dietziaceae, Intrasporangiaceae, Microbacteriaceae, Micrococcaceae, Micromonosporaceae, Streptomycetaceae, Aerococcaceae, Bacillaceae, Paenibacillaceae, Planococcaceae, and Staphylcoccaceae were commonly isolated across all tissues, and Flavobacteriaceae, Corynebacteriaceae, Yesiniaceae, Vibrionaceae, Hahellaceae, Pseudomonadaceae were also identified from the intestines. In microbial monitoring of four harmful bacteria, Streptomyces albus (96%) showed antibacterial activity against all four strains, and Agrococcus baldri (99%) and Psychrobacter nivimaris (99%) presented against E. Coli and E. aerogens. In addition, some strains with low homogeny were isolated and further experiments are therefore required, for example to refine the antimicrobial substances including new strain investigations. These additional experiments would aim to establish generic resources for the microbial communities in S. Supertexta and provide basic data for applied microbiological research.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.103-110
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• 2006

T-RFLP analysis and clone sequencing analysis based on bacterial 16S rDNA were conducted to assess bacterial community structure and diversity in Zoysia japonica soil treated with liquid fertilizer containing amino acids(LFcAA) after spray with herbicide. The results of T-RFLP (terminal restriction fragment length poly-morphism) analysis using restriction enzyme Hae III showed that the T-RFs of various size appeared evenly in the 32 clones of KD3 and 38 clones of KD4 respectively that had been treated with liquid fertilizer containing amino acid(LFcAA) compared to 23 clones of KD2 hat had not been treated with LFcAA. The microbial com- munity structure in KD2 appeared less diverse than those in KD3 and KD4. Analysis of partial sequences for 110 clones from KDI (control), KD2 (non-treated), KD3 (LFcAA 1X), KD4 (LFcAA 2X), respectively, revealed that most bacteria were related with uncultured bacteria in a 16S rDNA sequence similarity range of 91-99% through blast search. Otherwise, the other clones were members of proteobacteria, Acidobacteria, Act-inobacteria, Sphingobacteria and Planctomyces groups. Especially in KD4, members of Alpha Proteobacteria, Rhizobiales, Sphigomonadales, Caulobacterales, Gamma Proteobacteria, the genus Pseudomonas, Betapro-teobacteria, Nitrosomonadales and genus Nitrosospira appeared to be dominant. In addition, Acidobacteria group, Actinobacteria group, Planctomycetacia and Sphingobacteria were also shown. The microbial com-munity structure in Z. japonica soil sprayed with herbicide was affected by LFcAA.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.223-231
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• 2010

A total of 191 samples collected from the commercial swine farms located in Chungnam province were investigated by PCR to estimate the prevalence of Lawsonia (L.) intracellularis infection. In the group of the pigs with proliferative enteritis, 14 (93.3%) of 15 intestinal samples and 12 (80.0%) of 15 feces were positive in PCR. In contrast, a relatively low positive rate (18.0%, 29 of 161 samples) was determined in the group of normal healthy pigs. The group of pigs over 120 days showed the highest positive rates (26.8%, 15 of 56 samples). In the comparison of the sequences of 210bp for species specific fragments and 301bp for outer membrane protein, the isolates (L1. L2) showed almost 100% identity with the reference L. intracellularis (L08049, USA). For the sequences of partial 16s rDNA, the homologies among the 5 isolates (L1-L5) were 97.4% to 99.3%, and those of 5 sequences (L1-L5) versus 5 overseas reference strains of L. intracellularis ranged from 98.6% to 99.8%. In the comparison of the nucleotide sequences among 5 isolates and other species in Desulfovibrionales showed 82.4 to 99.5% identities. The 5 isolates shared relatively low identities (76.9% to 84.4%) with the species of alpha-proteobacteria. In phylogenetic analysis based on the 16s rDNA sequences, all of the 5 isolates (L1-L5) were located in the same branch with the strains of L. intracellularis that were previously isolated from the pigs in USA and China. Seven strains of Desulfovibrio sp. were clustered in the neighboring branches, whereas alpha and gamma Proteobacteria showed distant relationship with L. intracellularis strains. The present findings suggest that L. intracellularis infection is endemic in the swine farms in the regions, and that the domestic isolates maintained very limited genetic variation.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.150-156
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• 2000

Oligotrophic bacteria isolated from forest soil showed a specific community consisting of various taxonomic groups compared with those in other soil or aquatic habitats. Based on the cell shape, the isolates were divided into four groups: regular rod, curved/spiral rod, irregular rod, and prosthecate bacteria. The cellular fatty acids 60 oligotrophic isolates were analyzed. The 30 fatty acids which were identified or characterized are classified. At the dendrogram based on cellular fatty acid composition, four clusters(I-IV) were separated at a euclidian distance of about 50. Cluster 3 and 4-a strains were containing Q-8, these strains are accommodated in the Proteobacteria gamma and beta subdivision. The chemotaxonomic profiles of the cluster 4-a strains showed good agreement with those of the genus Burkholderia. Cluster 3 was characterized by the presence of branched-chain fatty acids, iso-C15:0, iso-C17:1, and iso-C17:0 as the major components. These chemotaxonomy suggested the close relationship of the isolates with Xathomonas/Sterotrophomonas group. Based on the 16S rDNA sequence analysis, the two representative strains(MH256 and MA828) of cluster 3 showed the close relation to genera, Xathomonas/Sterotrophomonas, but were not included in these genera. These strains were even further away from core Xanthomonas, and clearly were seen to branch outside the cluster formed by the Sterotrophomonas maltophilia. MH256 and MA828 16S rDNA sequence was different enough to put new genus on a separate branch. The isolates with Q-10 were also studied. They are corresponded to the two large groups in Proteobacteria alpha subdivision. One was incorporated in the genus Bradyrhizobium cluster, which also includes Agromonas, a genus for oligotrophic bacteria. The strains of the other group showed high similarity to the genus Agrobacterium.

• Korean Journal of Microbiology
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• v.35 no.3
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• pp.242-247
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• 1999

This sludy was conducted to investigate the change of bacterial co~munities with season and depth in Lake Soyang. Korea, using fluorescence in situ hybridization (FISH). The oligonucleotide probes used in this study were EUB338, ALF I b. GAM42a, and CF, The percentage of h e Proleobacteria a $\alpha$-group ranged from 0.70 to 33% the $\beta$-group from 1.0 to 26% they -group from 2.4 Lo 37% and Cytophagn and Flavobactefin groups from 4.7 to 24% duing the study period (April Lo November, 1998). They $\gamma$-group was dominant in spring when Asterionella was dominant. and a $\alpha$-group was dominant in summer when the organic content was low and Dinobryon was dominant. However, a specific group was not dominant in ？dl when cyanobacteria group was dominant and the ratio of eubacleria to total bacteria was very low. Therefore, the bacterial communities in Lake Soyang changed with season and depth, which seems to be associated with the telnporal succession of phytoplanlaons.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.209-220
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• 2015

In this study, gut bacterial communities in xylophagous insects were analyzed using the pyrosequencing of 16S rRNA genes for their potential biotechnological applications in lignocelluloses degradation. The result showed that operational taxonomic units (OTUs), species richness and diversity index were higher in the hindgut than in the midgut of all insect samples analyzed. The dominant phyla or classes were Firmicutes (54.0%), Bacteroidetes (14.5%), ${\gamma}-Proteobacteria$ (12.3%) in all xylophagous insects except for Rhinotermitidae. The principal coordinates analysis (PCoA) showed that the bacterial community structure mostly clustered according to phylogeny of hosts rather than their habitats. In our study, the two carboxymethyl cellulose (CMC)-degrading isolates which showed the highest enzyme activity were most closely related to Bacillus toyonensis $BCT-7112^T$ and Lactococcus lactis subsp. hordniae $NCDO\;2181^T$, respectively. Cellulolytic enzyme activity analysis showed that ${\beta}-1,4-glucosidase$, ${\beta}-1,4-endoglucanase$ and ${\beta}-1,4-xylanase$ were higher in the hindgut of Cerambycidae. The results demonstrate that xylophagous insect guts harbor diverse gut bacteria, including valuable cellulolytic bacteria, which could be used for various biotechnological applications.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.86-92
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• 2010

Thirty-one chicken feather-degrading bacteria were isolated from wasted feather, compost and wastewater in a chicken farm. These isolates were categorized as Firmicutes (21 strains), ${\gamma}$-proteobacteria (4 strains), Actinobacteria (4 strains), and Bacteroidetes (2 strains) by 16S rRNA gene sequence analysis. We examined the feather-degrading isolates for degradation in the 2% of chicken feather meal. The strain Chryseobacterium sp. FBF-7, Stenotrophomonas maltophilia FBS-4, and Lysinibacillus sp. FBW-3 were selected as a keratinolytic protein degrading bacteria which showed the highest feather degradation of 75-90%. The characteristics of amino acids extracted from chicken feather meal by using keratinolytic protein degrading isolates and chemical method with $Ca(OH)_2$ were analyzed. Total amino acid content of strain Chryseobacterium sp. FBF-7 was 1,661.6 ${\mu}mol$/ml, which was the highest and it was similar with chemical method. And essential amino acid content of total amino acid was thirty-seven percent (619.3 ${\mu}mol$/ml) and 596.9 ${\mu}mol$/ml for keratinolytic protein degrading isolates and chemical method, respectively. The major amino acids were valine, glutamic acid, aspartic acid, glycine, and proline by the strain Chryseobacterium sp. FBF-7 and especially, higher contents of aspartic acid, threonine, serine, cysteine, and tyrosine were detected compared with chemical method.