• Journal of Species Research
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• v.12 no.spc2
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• pp.23-32
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• 2023

During screening for indigenous prokaryotic species in Republic of Korea in 2021, a total of 21 bacterial strains assigned to the phylum Bacteroidota were isolated from a variety of environmental habitats including pine cone, seaweed, soil, sea sediment, brackish water and moss. Based on the 16S rRNA gene sequence similarity value of more than 98.7% and formation of a robust phylogenetic clade with the type strain of the closest bacterial species, it was found that the 21 strains belong to independent and recognized bacterial species. There has been no official report that the identified 21 species have been isolated in Republic of Korea up to date. Therefore, 16 species in six genera of two families in the order Flavobacteriales, two species in two genera of two families in the order Cytophagales, one species in one genus of one family in the order Chitinophagales and two species in one genus of one family in the order Sphingobacteriales are proposed as unrecorded species of the phylum Bacteroidota isolated in Republic of Korea. Their Gram reaction, colony and cell morphology, basic phenotypic characteristics, isolation source, taxonomic status, strain ID and other information are described in the species descriptions.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.593-604
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• 2023

Post-harvest handling and hygienic level of aquatic products significantly affect the quality and level of safety. Cold chain control is one of the determining factors for the quality of fish and the bacterial community that grows on the fish. Identification of spoilage bacteria and pathogens in aquatic products must be made because it will determine the physical and chemical quality. A molecular identification method with high sensitivity is the solution. This study aims to identify the quality of fish and bacterial communities that grow. The research procedures included sample collection, pH measurement, drip loss measurement, transportation and cold storage treatment, DNA extraction, DNA sequencing, sequence analysis, and bioinformatics analysis. The conclusion obtained from this study is that the simulation of the cold chain system applied to eastern little tuna does not significantly affect changes in the water activity value, pH, and drip loss. The insignificant change indicates that the eastern little tuna samples are still in good quality. The bioinformatics analysis showed the highest diversity and abundance of the bacterial community came from the Gammaproteobacterial class.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.328-335
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• 2013

As a result of conducting a cultural experiment of tomato using chicken feather protein hydrolysate (CPH) which was mass produced by keratin protein degrading bacterium Chryseobacterium sp. FBF-7 (KACC 91463P), we found that the stem and the root of tomato showed significant improvement in growth. For the purpose of phylogenic interpretation, a comparison was drawn between the effect of CPH, a treated CPH and untreated, on the changes of bacterial populations by 454 pyrosequencing based on 16S rRNA gene sequences. Tomato rhizosphere soil untreated with CPH (NCPH) showed 6.54 Shannon index from 3,281 sequence reads, and the rhizosphere soil treated with CPH (TCPH) showed 6.33 Shannon index from 2,167 sequence reads, displaying that it does not affect the diversity. Bacterial populations were composed of 19 phyla in the rhizosphere soil, and the phylum Proteobacteria occupied 40% of total bacterial populations. Bradyrhizobium, Agromonas, Nitrobacter, and Afipia (BANA group) which belong to Bradyrhizobiaceae were abundant and commonly detected in both the treated and untreated soils, suggesting the dominance of bacterial group in rhizosphere soil. The results obtained showed that CPH treatment does not affect the indigenous bacterial populations present in the rhizosphere soil.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.135-140
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• 2018

BACKGROUND: The Asian hornet (Vespa velutina nigrithorax), a wasp species, has attacked honey bee populations and affected the beekeeping industry in Korea over the past 15 years. However, little research has been done with this invasive species. In this study, we investigated the intestine bacterial microbiota of Asian hornets and honey bees to design an attractive trap for Asian hornets. METHODS AND RESULTS: Genomic DNAs isolated from the intestine microorganisms of Asian hornets and honey bees were utilized to amplify bacterial 16S rDNA for the comparative sequence analysis. The next generation sequencing analysis identified that the orders Flavobacteriales as the most abundant intestinal microorganisms in Asian hornets, showing a clear difference compared to honey bees in which Aeromonadales are dominant. We also report five newly identified 16S rDNA sequences of Asian hornet intestinal bacteria. According to the sequence blast search, these five bacteria belong to the genera Thalassomonas, Caedobacter, Vampirovibrio, Alkaliphilus and Calothrix. CONCLUSION: While Asian hornets and honey bees show similar intestine bacterial diversity, the relative ratio of bacterial populations is different. providing useful information to design pest control agents specifically targeting Asian hornets.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.72-79
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• 2001

The effect of phenol on the change of bacterial community in the effluent water from a wastewater treatment plant was analyzed by PCR and terminal restriction fragment length polymorphism (T-RFLP). The fragments of 16S rDNA were amplified by PCR with bacterial primers, where one of the primers was biotinylated at the 5'-end. After digestion with restriction enzymes, HaeIII and AluI, the biotinylated terminal restriction tragments (T-RFs) of the digested products were selectively isolated by using streptavidin paramagnetic particles. The single-stranded DNA of T-RFs was separated by electrophoresis on a polyacrylamide gel and detected by silver staining technique. When 10 standard strains were analyzed by our method, each strain had a unique T-RF which corresponded to the calculated size from the known sequences of RDP database. The T-RFLP fingerprint generated from the effluent water was very complex, and the predominant T-RFs corresponded to members of the genus Acinetobacter, Bacillus and Pseudomonas. In addition, the perturbation of bacterial community was observed when phenol was added to the sample at the final concentration of 250 $l^{-1}$. The number of T-RFs increased and the major bacterial population could be assigned to the genus Acinetobacter, Comamonas, Cytophaga and Pseudomonas. A intense band assigned to the putative genera of Acinetobacter and Cytophaga was eluted, amplified, and sequenced. The nucleotide sequence of the T-RF showed close relationship with the sequence of Acinetobacter junii.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.91-95
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• 2005

In the multidimensional protein identification technology of high-throughput proteomics, we use one-dimensional gel electrophoresis and after the separation by two-dimensional liquid chromatography, the sample is analyzed by tandem mass spectrometry. In this study, we have analyzed the Pseudomonas Putida KT2440 protein. From the protein identification, the protein database was combined with its reversed sequence database. From the peptide selection whose error rate is less than 1%, the SEQUEST database search for the tandem mass spectral data identified 2,045 proteins. For each protein, we compared the molecular weight calibrated from 1D-gel band position with the theoretical molecular weight computed from the amino acid sequence, by defining a variable MW$_{corr}$ Since the bacterial proteome is simpler than human proteome considering the complexity and modifications, the proteome analysis result for the Pseudomonas Putida KT2440 could suggest a guideline to build the protocol to analyze human proteome data.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.481-489
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• 2007

[ $\alpha$ ]-L-Arabinofuranosidases (AFases; EC 3.2.1.55) are exo-type enzymes, which hydrolyze terminal nonreducing arabinose residues from various polysaccharides such as arabinan and arabinoxylan. Genome-wide BLAST search showed that various bacterial strains possess the putative AFase genes with well-conserved motif sequences at the nucleotide and amino acid sequence levels. In this study, two sets of degenerate PCR primers were designed and tested to detect putative AFase genes, based on their three highly conserved amino acid blocks (PGGNFV, GNEMDG; and DEWNVW). Among 20 Bacillus-associated species, 13 species were revealed to have putative AFase genes in their genome and they share over 67% of amino acid identities with each other. Based on the partial sequence obtained from an isolate, an AFase from Geobacillus sp. was cloned and expressed in E. coli. Enzymatic characterization has verified that the resulting enzyme corresponds to a typical AFase. Accordingly, degenerate PCR primers developed in this work can be used for fast, easy, and specific detection and isolation of putative AFase genes from bacterial cells.

• Journal of Species Research
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• v.6 no.1
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• pp.25-41
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• 2017

As a subset study for the collection of Korean indigenous prokaryotic species, 62 bacterial strains belonging to the phylum Actinobacteria were isolated from various sources. Each strain showed higher 16S rRNA gene sequence similarity (>98.75%) and formed a robust phylogenetic clade with closest species of the phylum Actinobacteria which were defined with valid names, already. There is no official description on these 62 actinobacterial species in Korea. Consequently, unrecorded 62 species of 25 genera in the 14 families belonging to the order Actinomycetales of the phylum Actinobacteria were found in Korea. Morphological properties, basic biochemical characteristics, isolation source and strain IDs are described in the species descriptions.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.500-502
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• 2016

Several bacterial species have been reported to be surviving after the ionizing radiation treatment due to the presence of sophisticated enzymes systems and some endospores producing bacterial strains can also resist, due to the presence of thick spore coat. In this study, we report the complete genome sequence of a bacterium Paenibacillus swuensis $DY6^T$, isolated from an irradiated soil sample. The genome comprised of 5,012,599 bp with the G+C content of 49.93%, the genome included 4,463 protein coding genes and 133 RNA genes.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1605-1612
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• 2012

The present study concerned the identification and characterization of a novel bacterial strain isolated from entomopathogenic nematodes collected from different regions in Korea. The bacterial isolate M1021 was Gramnegative, bioluminescent, and produced red colonies on MacConkey agar medium. A rod-shaped structure was confirmed by the electron micrograph. Fatty acid composition was analyzed by using the Sherlock MIDI system. The identification was further supported by 16S rDNA sequence analysis, which revealed 96-99% sequence homology with strains of Photorhabdus temperata. The location of the isolated strain of P. temperata in the phylogenetic tree was confirmed and it was named P. temperata M1021. P. temperata M1021 exhibited catalase, protease, and lipase activities when grown on appropriate media supplemented with respective substrates. The culture of P. temperata M1021 exhibited insecticidal activity against the larvae of Galleria mellonella and the activity was the highest after 3-4 days of cultivation with agitating at $28^{\circ}C$ under 220 rpm. Antibacterial activity was also observed against Salmonella Typhimurium KCTC 1926 and Micrococcus luteus KACC 10488.