• 환경생물
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• 제40권4호
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• pp.442-454
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• 2022

A total of 31 bacterial strains were isolated from the Geum River basin in the Republic of Korea during our investigation of indigenous prokaryotic species. The isolated bacterial strains had high 16S rRNA gene sequence similarity (>98.7%) with those of validly published bacterial species, which have not been reported in Republic of Korea. The 31 bacterial strains were phylogenetically diverse and assigned to 4 phyla, 8 classes, 18 orders, 21 families, and 27 genera. At the genus level, the unreported species were affiliated with Kineococcus, Pedococcus, Rhodoluna, Salinibacterium, Rhodoluna, Arthrobacter, Williamsia, Nakamurella, Nocardioides of the class Actinobacteria, Patulibacter of the class Thermoleophilia, Pontibacter, Hymenobacter of the class Cytophagia, Flavobacterium of the class Flavobacteriia, Geomicrobium of the class Bacilli, Brevundimonas, Gellertiella, Rhizobium, Paracoccus, Taonella, Sphingomonas of the class Alphaproteobacteria, Burkholderia, Polaromonas, Hydrogenophaga, Chitinilyticum, Azospira, Zoogloea of the class Betaproteobacteria, and Pseudomonas of the class Gammaproteobacteria. The unreported bacterial species were further characterized by examining their morphological, cultural, physiological, and biochemical properties. The detailed descriptions of the 31 bacterial strains were provided.

• 환경생물
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• 제40권4호
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• pp.405-412
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• 2022

Suncheon Bay Ecological Park, possessing abundant fisheries and biological diversity, was registered as a Ramsar wetland in Korea. Approximately 300 bacterial strains were isolated from the Suncheon Bay in a comprehensive study of indigenous prokaryotic species conducted during 2019-2020 in South Korea. A total of 12 bacterial strains were identified using 16S rRNA gene sequencing, demonstrating >98.7% sequence similarity with validly published species. These species were determined to be unrecorded bacterial species in Korea. A total of six strains were isolated from brackish water and Phragmites communis Trin (reed) species. These unrecorded species were phylogenetically diverse and belonged to three classes, six orders, and ten genera. Regarding the genus and class levels, the previously unrecorded species belonged to Jiella, Martelella, Rhizobium, Paracoccus, Rhodovulum, and Altererythrobacter of the class Alphaproteobacteria; Mycolicibacterium, Demequina, and Microbacterium of the class Actinobacteria; Confluentibacter of the class Flavobacteria. The twelve species were further characterized by gram staining, colony and cell morphology, biochemical properties, and phylogenetic position.

• Parasites, Hosts and Diseases
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• 제62권1호
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• pp.151-156
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• 2024

Bovine borreliosis, caused by Borrelia theileri which is transmitted via hard tick bites, is associated with mild clinical symptoms, such as fever, lethargy, hemoglobinuria, anorexia, and anemia. Borrelia theileri infects various animals, such as cattle, deer, horses, goats, sheep, and wild ruminants, in Africa, Australia, and South America. Notably, no case of B. theileri infection has been reported in Korean cattle to date. In this study, 101 blood samples were collected from a Korean indigenous cattle breed, among which 1.98% tested positive for B. theileri via nested PCR. The obtained sequences exhibited high homology with B. theileri strains identified in other regions. Phylogenetic analysis of 16S rRNA confirmed the B. theileri group affiliation; however, flagellin B sequences exhibited divergence, potentially due to regional evolutionary differences. This study provides the first molecular confirmation of B. theileri infection in Korean livestock. Further isolation and nucleotide sequence analyses are necessary to better understand the presence of B. theileri strains in cows in Korea.

• Journal of Microbiology and Biotechnology
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• 제34권8호
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• pp.1636-1641
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• 2024

A Gram-stain-positive, aerobic, white-coloured, rod-shaped bacteria, designated as a strain dW9^T, was isolated from soil. Strain dW9^T was catalase-positive and oxidase-negative. Strain dW9^T grew at temperature of 20-37℃ and at pH of 5.0-7.0. Phylogenetic and 16S rRNA gene analysis indicated that strain dW9^T belonged to the genus Paenibacillus with its closest relative being Paenibacillus filicis S4^T (97.4% sequence similarity). The genome size of dW9^T was 7,787,916 bp with DNA G+C G+C content of 51.3%. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of dW9^T with its closest relatives were found to be <22.0% and <74.0%, respectively. The only respiratory quinone was MK-7, and the major fatty acids were antiso-C_15:0 and iso-C_16:0. Overall, the comprehensive taxonomic analysis revealed that strain dW9^T met all the fundamental criteria to be classified as a novel species within the genus Paenibacillus. Accordingly, we propose the name Paenibacillus gyeongsangnamensis sp. nov., with the type strain dW9^T (=KCTC 43431^T =NBRC 116022^T).

• Journal of Microbiology and Biotechnology
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• 제34권9호
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• pp.1819-1825
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• 2024

An aerobic, Gram-stain-negative, catalase-positive, rod-shaped, and motile bacteria, designated as a strain WR6^T was isolated from soil in Republic of Korea. Strain WR6^T grew at temperatures of 10-37℃, at pH of 5.0-9.0, and at NaCl concentrations of 0-3.0% (w/v). Phylogenetic and 16S rRNA gene nucleotide sequence analysis confirmed that strain WR6^T affiliated to the genus Mesorhizobium, with the nearest relative being Mesorhizobium waimense ICMP 19557^T (98.5%). The genome of strain WR6^T was 5,035,462 bp with DNA G+C content of 62.6%. In strain WR6^T, Q-10 was sole ubiquinone; summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and C_19:0 cyclo ω8c were predominant fatty acids; and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, and phosphatidylethanolamine were major polar lipids. Based on these polyphasic taxonomic data, strain WR6^T represents a novel species in the genus Mesorhizobium. Accordingly, we propose the name Mesorhizobium koreense sp. nov., with the type strain WR6^T (=KCTC 92695^T =NBRC 116021^T).

• 미생물학회지
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• 제49권1호
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• pp.58-63
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• 2013

본 연구는 한국 제주도 조간대에 서식하는 홍조류로부터 분리된 JIM57 균주의 계통학적 특성을 조사하기 위하여 수행되었다. 16S rRNA gene 염기서열을 분석한 결과, 본 균주는 Oceanisphaera 속과 대단히 유사하였으며, Oceanisphaera litoralis DSM $15406^T$와 98.02%, O. donghaessis KCTC $12522^T$와 97.7%의 염기서열 상동성을 나타내었다. 본 균주는 그람양성의 호기성 구균으로써, 0.5-8.0%의 NaCl 및 $4-47^{\circ}C$에서 생육할 수 있었다. 본 균주는 Oceanisphaera litoralis DSM $15406^T$와 일부 생리학적 및 생화학적 특성을 공유하였으나 ethanol, proline 및 alanine 이용성에서는 차이가 있었다. 본 균주 genomic DNA의 GC 함량은 61.94 mol%였으며, 주요 균체 지방산 지방산으로서 $C_{16:1}$ ${\omega}7c$, iso-$C_{15:0}$ 2-OH, $C_{16:0}$, and $C_{18:1}$ ${\omega}7c$를 함유하고 있었다. 또한 DNA-DNA 상동성을 조사한 결과, JIM57 균주는 O.litoralis DSM $15406^T$ 및 O. donghaessis KCTC $12522^T$와 별개의 종임을 알 수 있었다. 이러한 결과들을 종합한 결과, JIM57 균주(=KCTC 22371 =AM 983543 =CCUG 60764)는 O. litoralis DSM $15406^T$ 및 O. donghaessis KCTC $12522^T$와 다른 특성을 나타내는 것으로 확인되어 Oceanisphaera의 새로운 종임을 제안하였다.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.207-218
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• 2008

The impacts of planted transgenic rice varieties on bacterial communities in paddy soils were monitored using both cultivation and molecular methods. The rice field plot consisted of eighteen subplots planted with two genetically modified (GM) rice and four non-GM rice plants in three replicates. Analysis with denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes revealed that the bacterial community structures were quite similar to each other in a given month, suggesting that there were no significant differences in bacterial communities between GM and non-GM rice soils. The bacterial community structures appeared to be generally stable with the seasons, as shown by a slight variation of microbial population levels and DGGE banding patterns over the year. Comparison analysis of 16S rDNA clone libraries constructed from soil bacterial DNA showed that there were no significant differences between GM and non-GM soil libraries but revealed seasonal differences of phyla distribution between August and December. The composition profile of phospholipid fatty acids (PLFA) between GM and non-GM soils also was not significantly different to each other. When soil DNAs were analyzed with PCR by using primers for the bar gene, which was introduced into GM rice, positive DNA bands were found in October and December soils. However, no bar gene sequence was detected in PCR analysis with DNAs extracted from both cultured and uncultured soil bacterial fractions. The result of this study suggested that, in spite of seasonal variations of bacterial communities and persistence of the bar gene, the bacterial communities of the experimental rice field were not significantly affected by cultivation of GM rice varieties.

• 미생물학회지
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• 제51권1호
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• pp.86-95
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• 2015

독도의 해안에 군락을 이룬 해안식물 근권에서 호염성 및 염내성을 가지는 세균의 분리를 위해 3종의 해안식물의 군락을 선정한 후 각 식물의 군집 하부에서 토양시료를 채취하였다. 시료는 marine broth 한천배지를 이용하여 형태학적인 구분을 통해 순수분리 되었다. 분리된 161개 세균들을 NaCl 9.0% 농도로 조정된 배지에서 생존하는 26개 균주를 선발하여 genomic DNA를 얻은 후, 16S rRNA gene sequence를 증폭하여 부분동정 하였다. 이들의 유연관계 확인을 위해 계통수를 작성한 결과, 이들은 각각 Firmicutes (30.8%), Gamma proteobacteria (53.8%), Bacteroidetes (7.7%), Alpha proteobacteria (7.7%), Actinobacteria (7.7%)에 속하였으며, 이는 기존의 독도 토양 및 해수 미생물상 연구와 특징적 차이를 보인다. 또한, 분리된 세균의 종 조성도 기존 독도 토양 및 해양연구와 유의적으로 상이함을 보였다. 이에 더하여 선발된 26개 균주들 중에서 4균주가 12.0% 이상의 염농도에서 생장하였으며, 이들 중에서 3개 균주가 15.0% 이상의 염농도에서 생장하여 극호염성의 특성을 나타내었으며, 광범위한 염분농도에서도 생장하는 특성을 보였다. 이들은 해안식물 근권에서 독도 특유의 고염분 및 염분변화라는 환경적 스트레스를 극복하며 해안식물과 어떠한 상호작용을 하는 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.976-986
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• 2018

Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-to-phenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.

• 생명과학회지
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• 제17권3호통권83호
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• pp.402-406
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• 2007

우리나라에 분포하는 멧토끼 (Lepus coreanus)의 성판별을 위한 분자 표지자를 개발하기 위하여, X, Y 염색체간 상동인 ZFX와 ZFY 유전자들의 성별 이형성에 초점을 맞추어 본 연구를 수행하였다. ZFX와 ZFY 유전자의 인트론 7 영역은 멧토끼의 암수가 구분되는 증폭 양상을 나타내었다. 인트론 7의 길이는 각각 ZFX에서 538, ZFY에서 233-bp로 확인되었다. 특히, ZFX의 인트론 7에서는 RNA-매개성 전위인자 중 한 종이며 토끼의 유전체에서 빈번하게 관찰되는 CSINE2와 유사한 반복서열이 발견되었다. 반면, 반복서열은 ZFY의 인트론 7에서는 관찰되지 않았다. ZFX와 ZFY 유전자의 인트론 7에서 확인된 길이의 차이에 근거하여 중합효소연쇄반응 기법을 이용한 유전자 성판별을 수행하였다. 시험에 이용된 모든 DNA시료들은 ZFX에서 증폭된 공통의 밴드를 가지고 있었다. 이에 반해, 멧토끼 수컷 DNA들은 각각 ZFX와 ZFY에서 증폭된 두 개의 구분되는 밴드들을 나타내었다. ZFX-ZFY 유전자·성판별 결과는 표현형 성별 정보뿐만 아니라 수컷-특이적인 SRY 유전자의 증폭양상과도 일치한 결과와도 정확히 일치하였다. 이상의 결과들은 멧토끼에서 ZFX와 ZFY의 인트론 7 영역간의 성별 이형성은 유전자 성판별을 위한 유용한 유전자 표지자가 될 것으로 사료된다.