• Korean Journal of Microbiology
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• v.51 no.1
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• pp.31-38
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• 2015

The bacterial community structures of two marine sponges, Cinachyrella sp. and Plakortis sp., collected from Chuuk in the South Pacific in February 2012 were analyzed by PCR-DGGE (Denaturing Gradient Gel Electrophoresis) fingerprinting. After isolation of the total genomic DNAs from the sponges, the V3 regions of the 16S rRNA genes were amplified and subjected to DGGE profiling. The two species of sponges displayed different DGGE band patterns. The sequences derived from the DGGE bands revealed 85-100% similarities to known bacterial species in the public database. The bacterial community of Cinachyrella sp. was composed of 6 classes: Actinobacteria, Bacteroidetes, Chloroflexi, and Proteobacteria (Alpha-, Gamma-, Delta-). The bacterial community of Plakortis sp. included 7 classes: Actinobacteria, Chloroflexi, Firmicutes, Spirochaetes, and Proteobacteria (Alpha-, Gamma-, Delta-). Though Actinobacteria, Chloroflexi and Proteobacteria were commonly found in both sponges, the predominant bacterial communities differed between the two. Namely, the predominant bacterial groups in Cinachyrella sp. and Plakortis sp. were Proteobacteria and Chloroflexi, respectively. The sponge-associated bacteria are sponge host-specific, as each of the tested sponges from the same geographical location had different predominant bacterial diversity.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.269-277
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• 2016

Erm proteins methylate the specific adenine residue ($A_{2058}$, E. coli numbering) on 23S rRNA to confer the $MLS_B$ (macrolidelincosamide-streptogramin B) antibiotic resistance on a variety of microorganisms ranging from antibiotic producers to pathogens. When phylogenetic tree is constructed, two main clusters come out forming each cluster of Actinobacteria and Firmicutes. Two representative Erm proteins from each cluster were selected and their in vitro methylation activities were compared. ErmS and ErmE from Actinobacteria cluster exhibited much higher activities than ErmB and ErmC' from Firmicutes: 9 fold difference when ErmC' and ErmE were compared and 13 fold between ErmS and ErmB. Most of the difference was observed and presumed to be caused by N-terminal and C-terminal extra region from ErmS and ErmE, respectively because NT59TE in which N-terminal end 59 amino acids was truncated from wild type ErmS exhibited only 22.5% of wild type ErmS activity. Meanwhile, even NT59TE showed three and 2.2 times more activity when it was compared to ErmB and C, respectively, suggesting core region from antibiotic producers contains extra structure enabling higher activity. This is suggested to be possible through the extra region of 197RWS199 (from both ErmS and ErmE), 261GVGGSLY267 (from ErmS), and 261GVGGNIQ267 (from ErmE) and 291SVV293 (from ErmS) and 291GAV293 (from ErmE) by multiple sequence alignment.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.242-250
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• 2017

Actinobacteria tolerating extreme conditions can be a rich source of bioactive compounds and enzymes. In this study filamentous actinobacteria were isolated from soils of Ulleung Island, and their physiological properties were examined. Soil samples were collected, serially diluted and spread on various agar media. The average viable counts of total bacteria were $1.28{\times}10^7CFU/g$ for soil sample 1 (ULS1) and $2.05{\times}10^7CFU/g$ for soil sample 2 (ULS2). As a result, 34 strains of actinobacteria were isolated and assigned to the genera Streptomyces (16 strains), Isoptericola (5 strains), Rhodococcus (4 strains), Agromyces (3 strains), Micrococcus (2 strains), Arthrobacter (1 strain), Williamsia (1 strain), Microbacterium (1 strain), and Oerskovia (1 strain) based on 16S rRNA gene sequence analysis. Enzyme activity and plant growth promoting potential were tested for representative isolates. Multiple strains of Streptomyces degraded starch, casein and Tween 80. As for plant growth promoting potential, strains of Oerskovia, Williamsia, Isoptericola, and Streptomyces solubilized phosphate, and those of Agromyces, Oerskovia, Micrococcus, Rhodococcus, Streptomyces, and Isoptericola produced 3-indole-acetic acid (IAA), respectively. Selected strains of Streptomyces exhibited strong antagonistic activity against Staphylococcus aureus and Bacillus subtilis as well as Candida albicans. This study confirms that actinobacteria from Ulleung Island can be a good source of novel bioactive compounds.

• Korean Journal of Heritage: History & Science
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• v.47 no.4
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• pp.92-105
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• 2014

Microbial characteristics of bacterial population were investigated in human remains and soil inside the bones in excavated grave no.4 and no.5 at Keundokgol site, Osu-ri, Buyeo. Phylogenetic characteristics of bacterial populations were analyzed by direct extracting of ancient DNA. In this study, based on the 16S rDNA sequences, in case of grave no.4, 319s from human remain were classified into 11 phyla, and 462s from soil were classified into 16 phyla. In case of grave no.5, 271s from human remain were classified into 10 phyla, and 497s from soil were classified into 11 phyla. Especially, Actinobacteria phylogenetic group are dominant group of bacterial populations in grave no.4 and no.5. Also, most of these were analyzed uncultured group. Thus, the discovery of a diversely microbial community and uncultured group was thought to be due to the specificity of the sample. Conclusively the general excavated human bones were contaminated with soil bacteria species their near around. This results contribute to preservation and management of ancient human bone from archaeological sites.

• Journal of Species Research
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• v.6 no.1
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• pp.1-14
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• 2017

As a subset study to discover indigenous prokaryotic species in Korea in 2014, a total of 34 bacterial strains assigned to the phylum Actinobacteria were isolated from various environmental samples collected from activate sludge, biotite, freshwater, gut of marine organisms, mud flat, sediment, soil, spent mushroom compost and sea water. On the basis of high 16S rRNA gene sequence similarity and a tight phylogenetic association with the closest species, it was revealed that each strain was assigned to independent and previously described bacterial species, with the exception of one isolate. There is no official report that these 34 species included in the phylum Actinobacteria have been described in Korea: 6 species of 5 genera in the order Corynebacteriales, 1 species of 1 genus in the order Frankiales, 2 species of 2 genera in the Micromonosporales, 14 species of 10 genera in Micrococcales, 2 species of 2 genera in the Propionibacteriales, 1 species of 1 genus in the Pseudonocardiales, 4 species of 2 genera in the Streptomycetales, 2 species of 2 genera in the Streptosporangiales and 1 species of 1 genus in the Solirubrobacterales. Gram reaction, cell and colony morphology, pigmentation, physiological characteristics, isolation sources and strain IDs are described in the section of species description.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.59-64
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• 2016

In this study, a pyrosequencing was performed and analyzed to verify the phylogenetic diversity of actinomycetes in the bamboo (Sasa borealis) soil as a base study to obtain the genetic resources of actinomycetes. It was found that the rhizosphere soil had much various distribution in bacterial communities showing a diversity of 8.15 with 2,868 OTUs, while the litter layer showed a diversity of 7.55 with 2,588 OTUs. The bacterial community in the bamboo soil was composed of 35 phyla and the predominant phyla were Proteobacteria (51-60%), Bacteroidetes (16-20%), Acidobacteria (4-16%) and Actinobacteria (4-14%). In particular, Actinobacteria including Micromonosporaceae and Streptomycetaceae had a diverse distribution of actinomycetes within the six orders, 35 families and 121 genera, and it was characterized that about 83% of actinomycetes within Actinomycetales belonged to the 28 families. Among the dominant actinobacterial populations, Micromonosporaceae, Pseudonocardiaceae and Streptomycetaceae were representative family groups in the bamboo soils.

• Journal of Microbiology
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• v.45 no.5
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• pp.394-401
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• 2007

In this study, bacterial communities within the guts of several longicorn beetles were investigated by a culture-dependent method. A total of 142 bacterial strains were isolated from nine species of longicorn beetle, including adults and larvae. A comparison of their partial 16S rRNA gene sequences showed that most of the bacteria constituting the gut communities can typically be found in soil, plants and the intestines of animals, and approximately 10% were proposed as unreported. Phylogenetic analysis demonstrated that the bacterial species comprised 7 phyla, and approximately half were Gammaproteobacteria. Actinobacteria were the second most populous group (19%), followed by Firmicutes (13%) and Alphaproteobacteria (11%). Betaproteobacteria, Flavobacteria, and Acidobacteria were minor constituents. The taxonomic compositions of the isolates were variable according to the species of longicorn beetle. Particularly, an abundance of Actinobacteria existed in Moechotypa diphysis and Mesosa hirsute, which eat broadleaf trees; however, no Actinobacteria were isolated from Corymbia rubra and Monochamus alternatus, which are needle-leaf eaters. Considerable proportions of xylanase and pectinase producing bacteria in the guts of the longicorn beetles implied that the bacteria may play an important role in the digestion of woody diets. Actinobacteria and Gammaproteobacteria were the dominant xylanase producers in the guts of the beetles.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.177-182
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• 2010

The bacterial community structure of two marine sponges, Spirastrella abata and Cinachyrella sp. collected from Jeju Island, in April 2009, was analyzed by 16S rDNA-denaturing gradient gel electrophoresis (DGGE). DGGE banding patterns indicated 8 and 7 bands for Spirastrella abata and Cinachyrella sp., respectively. Comparative sequence analysis of variable DGGE bands revealed from 92% to 100% similarity to the known published sequences. The bacterial groups associated with Spirastrella abata were Alphaproteobacteria and Deltaproteobacteria. The bacterial community of Cinachyrella sp. consisted of Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria. Alphaproteobacteria was common and predominant in both the sponge species. Deltaproteobacteria was found only in Spirastrella abata while Actinobacteria and Gammaproteobacteria were found only in Cinachyrella sp. The results revealed that though the common bacterial group was found in both the sponges, the bacterial community profiles differed between the two sponge species obtained from the same geographical location.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1670-1680
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• 2017

Lignocellulose, composed mostly of cellulose, hemicellulose, and lignin generated through secondary growth of woody plant, is considered as promising resources for biofuel. In order to use lignocellulose as a biofuel, biodegradation besides high-cost chemical treatments were applied, but knowledge on the decomposition of lignocellulose occurring in a natural environment is insufficient. We analyzed the 16S rRNA gene and metagenome to understand how the lignocellulose is decomposed naturally in decayed Torreya nucifera (L) of Bija forest (Bijarim) in Gotjawal, an ecologically distinct environment. A total of 464,360 reads were obtained from 16S rRNA gene sequencing, representing diverse phyla; Proteobacteria (51%), Bacteroidetes (11%) and Actinobacteria (10%). The metagenome analysis using single molecules real-time sequencing revealed that the assembled contigs determined originated from Proteobacteria (58%) and Actinobacteria (10.3%). Carbohydrate Active enZYmes (CAZy)- and Protein families (Pfam)-based analysis showed that Proteobacteria was involved in degrading whole lignocellulose, and Actinobacteria played a role only in a part of hemicellulose degradation. Combining these results, it suggested that Proteobacteria and Actinobacteria had selective biodegradation potential for different lignocellulose substrates. Thus, it is considered that understanding of the systemic microbial degradation pathways may be a useful strategy for recycle of lignocellulosic biomass, and the microbial enzymes in Bija forest can be useful natural resources in industrial processes.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.334-343
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• 2021

Various vegetables, including cucumbers, have a high probability of foodborne illness because they are usually eaten raw. In this study, we analyzed the 16S rRNA gene sequences of the cucumber (Cucumis sativus L.) microbiota. The diversity indices of cucumber cultivated in May were higher than in cucumber cultivated in November. At the phylum level, Proteobacteria, Firmicutes, and Actinobacteria were predominant. The classes generally comprised Gammaproteobacteria, Bacilli, Alphaproteobacteria, and Actinobacteria. At the genus level, the proportions of Aureimonas, Escherichia, and Microbacterium in samples from May were relatively high, whereas Enterococcus, Pseudomonas, and Rhizobium accounted for a higher proportion in samples from November. Moreover, it is noteworthy that potential pathogenic genera such as Acinetobacter, Aerococcus, Aureimonas, Enterobacter, Enterococcus, Escherichia, Pantoea, Pseudomonas, and Staphylococcus were detected. Although further studies on the characteristics of potential pathogens are required, our results can be used to improve the food safety of vegetables.