• Journal of Species Research
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• 제9권4호
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• pp.339-345
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• 2020

The Earth contains billions of microbial species, although the vast majority cannot be cultured in laboratories and are thus considered unidentified and uncharacterized. Extremophiles are microorganisms that thrive in extreme conditions, including temperature, salinity, and pH. Extremophilic microorganisms have provided important insights for biological, metabolic, and evolutionary studies. Between 2017 and 2019, as part of a comprehensive investigation to identify bacterial species in Korea, eight bacterial strains were isolated from marine and non-marine environments in Jeju Island. These strains were cultured under extreme salinity or pH conditions. Phylogenetic analysis using 16S ribosomal RNA(rRNA) gene sequencing indicated that all eight strains belonged to the phyla Gammaproteobacteria, Bacilli, and Alphaproteobacteria. Based on their high 16S rRNA gene sequence similarities(>98.7%) and the formation of strong monophyletic clades with their closest related species, all isolated strains were considered as an unrecorded strain, previously unidentified species. Gram stain reaction, culture conditions, colony and cell morphology, biochemical characteristics, isolation source, and National Institute of Biological Resources(NIBR) IDs are described in this article. The characterization of these unrecorded strains provides information on microorganisms living in Korea.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.321-334
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• 2017

Process surveillance within agricultural biogas plants (BGPs) was concurrently studied by high-throughput 16S rRNA gene amplicon sequencing and an optimized quantitative microscopic fingerprinting (QMF) technique. In contrast to 16S rRNA gene amplicons, digitalized microscopy is a rapid and cost-effective method that facilitates enumeration and morphological differentiation of the most significant groups of methanogens regarding their shape and characteristic autofluorescent factor 420. Moreover, the fluorescence signal mirrors cell vitality. In this study, four different BGPs were investigated. The results indicated stable process performance in the mesophilic BGPs and in the thermophilic reactor. Bacterial subcommunity characterization revealed significant differences between the four BGPs. Most remarkably, the genera Defluviitoga and Halocella dominated the thermophilic bacterial subcommunity, whereas members of another taxon, Syntrophaceticus, were found to be abundant in the mesophilic BGP. The domain Archaea was dominated by the genus Methanoculleus in all four BGPs, followed by Methanosaeta in BGP1 and BGP3. In contrast, Methanothermobacter members were highly abundant in the thermophilic BGP4. Furthermore, a high consistency between the sequencing approach and the QMF method was shown, especially for the thermophilic BGP. The differences elucidated that using this biphasic approach for mesophilic BGPs provided novel insights regarding disaggregated single cells of Methanosarcina and Methanosaeta species. Both dominated the archaeal subcommunity and replaced coccoid Methanoculleus members belonging to the same group of Methanomicrobiales that have been frequently observed in similar BGPs. This work demonstrates that combining QMF and 16S rRNA gene amplicon sequencing is a complementary strategy to describe archaeal community structures within biogas processes.

• 한국미생물·생명공학회지
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• 제40권3호
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• pp.268-273
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• 2012

인도네시아 지열지대의 미생물 다양성을 16S rRNA 염기서열 분석을 통해 조사하였다. 전체적으로 어떠한 phylum 계통군에도 포함되지 않는 unclassified bacteria가 20.0-26.5% 존재하였으며 sampling 지역에 상관없이 Proteobacteria가 우점 phylum 계통군으로 나타났다. Cisolok 주변의 지열 지역을 조사한 결과 ${\beta}$-Proteobacteria (27.1%)와 Cyanobacteria (11.0%)가 높은 비율을 차지한 반면 Kamojang의 화산 주변 지역의 경우에는 ${\gamma}$-Proteobacteria (51.5%) 그리고 Aquificales (12.9%)가 우점 계통군으로 나타났다. 또한 Likupang 열수구의 경우에는 ${\gamma}$-Proteobacteria (33.3%)와 Bacteroidetes (27.6%)가 높은 비율로 나타났다. 본 연구를 통해 인도네시아 각 지열지대에 분포하는 미생물 군집은 각 지역의 환경적인 특징 (극한 지열 및 해양 서식지)과 밀접한 연관성이 있음을 알 수 있었다.

• 한국수산과학회지
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• 제33권2호
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• pp.103-109
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• 2000

열목어를 비롯한 산천어, 시마연어, 연어, 무지개송어 등 우리나라 연어아과 어류의 집단구조분석을 위한 기초자료를 얻기 위하여, 미토콘드리아 ribosomal RMA 유전자 영역의 염기서열변이를 비교${\cdot}$분석하였다. 미토콘드리아 DNA의 125 rRNA(945 bases, 열목어 의 경우 946 bases), Valine transfer RNA (72 bases), 및 16S rRNA(1513 bases) 등 3개의 유전자 영역에 걸쳐, 최대 2531 bases의 염기서열을 PCR/direct sequencing하여 얻었는데, 모든 염기변이중 전이가 월등히 우세하게 나타났으며, 종내${\cdot}$종간변이율은 모두 $0.5{\%}$이하로 낮게 나타나, 다른 영역에 비해 rRNA 유전자 영역에서의 염기서열이 매우 보존적임을 보여주었다. 또한, 미토콘드리아 rRNA 유전자 염기서열은 연어류의 속 (genus)단계 이상에서 집단분류표지인자로 유용하게 쓰일 수 있으리라 사료되어진다. 미토콘드리아 rRNA 염기서열자료를 기초로 구성된 phylogenetic tree를 통해 이들 종간의 진화적인 유연관계를 살펴본 결과, 시마연어가 무지개송어보다는 연어와 더 근연인 것으로 나타났으며, 열목어는 가장 유연이 먼 종임을 확인할 수 있었다.

• 한국환경농학회지
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• 제39권1호
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• pp.26-35
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• 2020

BACKGROUND: Microbes that govern a unique biochemical process of oxidizing ammonia into dinitrogen gas, such as anaerobic ammonium oxidation (anammox) have been reported to play a pivotal role in agricultural soils and in oceanic environments. However, limited information for anammox bacterial abundance and distribution in the terrestrial habitats has been known. METHODS AND RESULTS: Phylogenetic and next-generation sequencing analyses of bacterial 16S rRNA gene were performed to examine potential anammox bacteria in paddy soils. Through clone libraries constructed by using the anammox bacteria-specific primers, some clones showed sequence similarities with Planctomycetes (87% to 99%) and anammox bacteria (94% to 95%). Microbial community analysis for the paddy soils by using Illumina Miseq sequencing of 16S rRNA gene at phylum level was dominated by unclassified Bacteria at 33.2 ± 7.6%, followed by Chloroflexi at 20.4 ± 2.0% and Acidobacteria at 17.0 ± 6.5%. Planctomycetes that anammox bacteria are belonged to was 1.5% (± 0.3) on average from the two paddy soils. CONCLUSION: We suggest evidence of anammox bacteria in the paddy soil. In addition to the relatively well-known microbial processes for nitrogen-cycle, anammox can be a potential contributor on the cycle in terrestrial environments such as paddy soils.

• 한국미생물·생명공학회지
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• 제48권2호
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• pp.193-204
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• 2020

Sixteen acetic acid bacteria (AAB) were isolated from blueberries and citric fruits of the Salto Grande region (Concordia, Entre Rios, Argentina) using enrichment techniques and plate isolation. Enrichment broths containing ethanol and acetic acid enabled maximum AAB recovery, since these components promote their growth. Biochemical tests allowed classification of the bacteria at genus level. PCR-RFLP of the 16S rRNA and PCR-RFLP of the 16S-23S rRNA intergenic spacer allowed further classification at the species level; this required treatment of the amplified products of 16S and 16S-23S ITS ribosomal genes with the following restriction enzymes: AluI, RsaI, HaeIII, MspI, TaqI, CfoI, and Tru9I. C7, C8, A80, A160, and A180 isolates were identified as Gluconobacter frateurii; C1, C2, C3, C4, C5, C6, A70, and A210 isolates as Acetobacter pasteurianus; A50 and A140 isolates as Acetobacter tropicalis; and C9 isolate as Acetobacter syzygii. The bacteria identified by 16S rRNA PCR-RFLP were validated by 16S-23S PCR-RFLP; however, the C1 isolate showed different restriction patterns during identification and validation. Partial sequencing of the 16S gene resolved the discrepancy.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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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.

• Journal of Microbiology and Biotechnology
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• 제18권10호
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• pp.1678-1682
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• 2008

To investigate lactic acid bacterial population in Korean traditional rice wines, biotyping was performed using cell morphology and whole-cell protein pattern analysis by SDS-PAGE, and then the isolates were identified by 16S rRNA sequencing analysis. Based on the morphological characteristics, 103 LAB isolates were detected in wine samples, characterized by whole-cell protein pattern analysis, and they were then divided into 18 patterns. By 16S rRNA gene sequencing, the isolates were identified as Lactobacillus paracasei, Lb. arizonensis, Lb. plantarum, Lb. harbinensis, Lb. parabuchneri, Lb. brevis, and Lb. hilgardii when listed by their frequency of occurrence. It was found that the difference in bacterial diversity between rice and grape wines depends on the raw materials, especially the com position of starch and glucose.

• 생명과학회지
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• 제12권2호
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• pp.158-163
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• 2002

남조류 Microcystis aeruginosa를 무균적으로 분리하기 위해 낙동강 물금지역의 수화를 멸균 증류수로 vortex 전처리를 하였으며, 세균제거 및 무균상태를 계속 유지하기 위하여 항생물질(ampicillin 150 $\mu$g/$m\ell$, neomycin 25 $\mu$g/$m\ell$)을 배지에 첨가하고, 독립 집락으로 형성시켜 오염 기회를 줄이기 위하여 0.7% agarose로 고형화시킨 CB고체배지에서 3$0^{\circ}C$, 40 $\mu$mol m$^{-2}$ s$^{-1}$ 광 조건으로 배양하였다. 그 결과 분리되어진 26개의 Microcystis aeruginosa colony 중 3개의 무균 균주만이 확보되었다. 3개의 무균균주를 16S rRNA primer를 이용하여 PCR 증폭한 결과 M. aeruginosa AF 139292와 99.5에서 100%의 상동성을 가지는 것으로 나타났다.

• 미생물학회지
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• 제55권3호
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• pp.220-225
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• 2019

최근 10년간 미생물생태분석 기반의 연구는 차세대염기서열분석법이 개발된 이래로 지속적으로 증가하고 있다. 장내미생물생태와 건강의 연관성은 미생물 생태학 분야에 있어서 중요한 결과로 여겨지고 있다. 미생물 군집 분석은 주로 16S rRNA 유전자 가변 영역의 염기서열을 통해 분석되지만 이는 미생물의 활성 정보를 제공하지 않는다. 본 연구에서는 cDNA 기반의 미생물 생태분석을 수행하고 DNA 및 cDNA기반의 미생물생태분석 결과를 비교하였다. 두 가지의 서로 다른 접근법이 Butyrate producer와 probiotics와 같이 장내 대사과정에서 중요한 미생물의 abundance 뿐만 아니라 비만 지표로 알려진 Firmicutes 와 Bacteroidetes의 비율에 있어서 차이가 있음을 나타내었다. 따라서, cDNA 기반 미생물 군집은 이전에 수행된 DNA 기반 미생물 군집 분석과 비교하여 장내미생물생태의 역할과 관련된 또 다른 분석 방향성을 제공한다.