• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 가을 학술발표회 발표논문집
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• pp.233-235
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• 2003

한국 서해안과 남해안 47개소의 해수와 mud 시료로부터 광합성세균으로 유추되는 13개의 균주를 분리하였고, agar-shake tube method와 RAPD-PCR을 이용하여 4개 서로 다른 균주를 순수분리 하였다. 4개의 균주 중 폐수분해능이 가장 뛰어난 균을 선정하여, 형태학적, 배양적, 생화학적 특성 및 16S rRNA sequencing에 의한 동정결과 purple, sulfur bacteria 쪽에 가까웠으나 형태학적, 배양학적, 생화학적 특성이 purple, non-sulfur bacteria의 Rhodobacter 속에 가장 근접하여, Rhodobacter sp. EGH-24로 명명하였다.

• Fisheries and Aquatic Sciences
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• 제22권7호
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• pp.14.1-14.8
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• 2019

Olive flounder (Paralichthys olivaceus) is the major species developed for aquaculture in South Korea. Over the long history of olive flounder aquaculture, complex and diverse diseases have been a major problem, negatively impacting industrial production. Vibriosis is a prolific disease which continuously damages olive flounder aquaculture. A bacterial disease survey was performed from January to June 2017 on 20 olive flounder farms on Jeju Island. A total of 1710 fish were sampled, and bacteria from the external and internal organs of 560 fish were collected. Bacterial strains were identified using 16 s rRNA sequencing. Twenty-seven species and 184 strains of Vibrio were isolated during this survey, and phylogenetic analysis was performed. Bacterial isolates were investigated for the distribution of pathogenic and non-pathogenic species, as well as bacterial presence in tested organs was characterized. V. gigantis and V. scophthalmi were the dominant non-pathogenic and pathogenic strains isolated during this survey, respectively. This study provides data on specific Vibrio spp. isolated from cultured olive flounder in an effort to provide direction for future research and inform aquaculture management practices.

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.227-235
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• 2018

Foodborne illness represents a major threat to public health and is frequently attributed to pathogenic microorganisms on fresh produce. Recurrent outbreaks often come from vegetables that are grown close to or within the ground. Therefore, the first step to understanding the public health risk of microorganisms on fresh vegetables is to identify and describe microbial communities. We investigated the phyllospheres on Chinese cabbage (Brassica rapa subsp. pekinensis, N = 54). 16S rRNA gene amplicon sequencing targeting the V5-V6 region of 16S rRNA genes was conducted by employing the Illumina MiSeq system. Sequence quality was assessed, and phylogenetic assessments were performed using the RDP classifier implemented in QIIME with a bootstrap cutoff of 80%. Principal coordinate analysis was performed using a weighted Fast UniFrac matrix. The average number of sequence reads generated per sample was 34,584. At the phylum level, bacterial communities were composed primarily of Proteobacteria and Bacteroidetes. The most abundant genera on Chinese cabbages were Chryseobacterium, Aurantimonadaceae_g, Sphingomonas, and Pseudomonas. Diverse potential pathogens, such as Pantoea, Erwinia, Klebsiella, Yersinia, Bacillus, Staphylococcus, Salmonella, and Clostridium were also detected from the samples. Although further epidemiological studies will be required to determine whether the detected potential pathogens are associated with foodborne illness, our results imply that a metagenomic approach can be used to detect pathogenic bacteria on fresh vegetables.

• Journal of Microbiology
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• 제44권2호
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• pp.155-161
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• 2006

Comparative analysis of microbial communities in a sequencing batch reactor which performed enhanced biological phosphorus removal (EBPR) was carried out using a cultivation-based technique and 16S rRNA gene clone libraries. A standard PCR protocol and a modified PCR protocol with low PCR cycle was applied to the two clone libraries of the 16S rRNA gene sequences obtained from EBPR sludge, respectively, and the resulting 424 clones were analyzed using restriction fragment length polymorphisms (RFLPs) on 16S rRNA gene inserts. Comparison of two clone libraries showed that the modified PCR protocol decreased the incidence of distinct fragment patterns from about 63 % (137 of 217) in the standard PCR method to about 34 % (70 of 207) under the modified protocol, suggesting that just a low level of PCR cycling (5 cycles after 15 cycles) can significantly reduce the formation of chimeric DNA in the final PCR products. Phylogenetic analysis of 81 groups with distinct RFLP patterns that were obtained using the modified PCR method revealed that the clones were affiliated with at least 11 phyla or classes of the domain Bacteria. However, the analyses of 327 colonies, which were grouped into just 41 distinct types by RFLP analysis, showed that they could be classified into five major bacterial lineages: ${\alpha},\;{\beta},\;{\gamma}-$ Proteobacteria, Actinobacteria, and the phylum Bacteroidetes, which indicated that the microbial community yielded from the cultivation-based method was still much simpler than that yielded from the PCR-based molecular method. In this study, the discrepancy observed between the communities obtained from PCR-based and cultivation-based methods seems to result from low culturabilities of bacteria or PCR bias even though modified culture and PCR methods were used. Therefore, continuous development of PCR protocol and cultivation techniques is needed to reduce this discrepancy.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1464-1472
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• 2014

The microbial community structures of two continuous stirred tank reactors digesting turkey manure with pine wood shavings as well as chicken and swine manure were investigated. The reactor fed with chicken/swine wastes displayed the highest organic acids concentration (up to 15.2 g/l) and ammonia concentration (up to 3.7 g/l ammonium nitrogen) and generated a higher biogas yield (up to $366ml/g_{VS}$) compared with the reactor supplied with turkey wastes (1.5-1.8 g/l of organic acids and 1.6-1.7 g/l of ammonium levels; biogas yield was up to $195ml/g_{VS}$). The microbial community diversity was assessed using both sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Additionally, methanogens were analyzed using methyl coenzyme M reductase alpha subunit (mcrA) genes. The bacterial community was dominated by members of unclassified Clostridiales with the prevalence of specific clostridial phylotypes in each reactor, indicating the effect of the substrate type on the community structure. Of the methanogenic archaea, methanogens of the genus Methanosarcina were found in high proportions in both reactors with specific methanosarcinas in each reactor, whereas the strict hydrogenotrophic methanogens of Methanoculleus sp. were found at significant levels only in the reactor fed with chicken/swine manure (based on the analyses of 16S rRNA gene). This suggests that among methanogenic archaea, Methanosarcina species which have different metabolic capabilities, including aceticlastic and hydrogenotrophic methanogenesis, were mainly involved in anaerobic digestion of turkey wastes.

• 미생물학회지
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• 제47권2호
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• pp.130-136
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• 2011

러시아의 바이칼에 존재하는 고유종인 Baikalospongia과 Lubomirskia의 sponge로부터 방선균을 분리하였다. 분리된 방선균은 16S rRNA gene 분석 결과, Streptomyces griseoplanus, S. halstedii, S. violascens, S. flavovirens, S. microflavus에 각각 속하였다. 이 방선균들은 온도, 탄소이용, enzyme 활성, fatty acid 조성 등의 실험 결과에서, 각각 서로 다른 특징을 나타냈었다. 분리된 방선균의 배양온도는 30-37, pH는 8-9, 염분농도는 0-1.5에서 가장 잘 자라는 것으로 확인되었다. 주요 cellular fatty acid는 anteiso-$C_{15:0}$, iso-$C_{15:0}$ and iso-$C_{16:0}$로 나타났다. 특히 ATS-BA-19는 DNase와 chitinase 활성을 나타내었고, ATS-BA-16는 cellulase와 protease 활성을 나타내는 것으로 확인되었다. 또 두개의 분리된 방선균에서 그람음성 균주인 Pseudomonas aeruginosa에서 생장을 저해함을 확인하였다.

• 생명과학회지
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• 제28권9호
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• pp.1118-1126
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• 2018

본 논문은 양식 어류에게 많은 경제적 피해를 입히고 있는 다양한 어류질병세균 중에서 연쇄구균증에 대한 일반적인 특성과 종류, 진단 방법에 대하여 기존에 연구 보고된 논문을 기반으로 알아보고자 한다. 대표적인 어류연쇄구균증의 원인체로는 Lactococcus garvieae, Streptococcus iniae, S. parauberis가 있다. 연쇄구균증에 감염 시 나타나는 증상으로는 체색변화, 안구이상, 아가미 퇴색, 출혈, 복부팽만, 신장과 비장의 종대 등의 보이다 폐사가 일어난다. 또한 수온이 상승하는 6월부터 10월까지 주로 일어나며 집단적으로 발병하여 폐사가 일어난다. 현재 연쇄구균증을 진단하기 위한 기술로는 16S rRNA, 16S-23S rRNA intergenic spacer region (ISR), Random Amplified polymorphic DNA (RAPD), Ribotyion (RT), Loop-mediated isothermal amplification (LAMP) 등이 있다. 이중에서 현장에서 적용 가능성이 높은 LAMP법이 각광을 받고 있지만 결과 확인 등의 문제로 인하여 현재는 어려움을 겪고 있는 실정이다. 이에 현장에서 진단부터 결과 확인까지 손쉽게 사용할 수 있도록 문제점을 보완하면 연쇄구균증에 대한 경제적 손실을 최소화 할 것으로 사료된다.

• 한국어병학회지
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• 제19권2호
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• pp.127-139
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• 2006

2002년에서 2004년에 걸쳐, 우리 나라의 넙치 양식장에서 질병의 증상이 보이는 중간 육성 단계의 넙치를 대상으로 다수의 Vibrio속 세균을 분리 동정하였으며 그 중에서 V. ichthyoenteri균이 높은 비율을 차지하고 있었다. 일반적으로 V. ichthyoenteri는 넙치의 자어기 장관백탁증의 원인균으로 잘 알려져 있으며, 미성어의 병어로부터 분리되었다는 점에서 여러 크기의 넙치 및 종묘 생산에 미치는 영향을 알고자 하였다. 본 연구는 미성어 넙치에서 분리된 균주그룹과 장관백탁증에 걸린 넙치 자어에서 분리한 V. ichthyoenteri 참조 균주 두 그룹간의 생화학적 및 생리학적 성상, 유전학적 특성을 비교 분석함으로서 분리 균주를 V. ichthyoenteri로 동정하고, 이들의 어병학적 특성을 조사하였다.실험 결과 시험 균주와 참조 균주간의 생화학적 특성과 생리학적 성상이 거의 동일한 것으로 나타났다.본 연구에서 분리 균주와 참조 균주의 16S-23S rRNA intergenic space (IGS) region을 cloning하여 염기 서열을 분석한결과 3개의 참조 균주와 19개의 분리 균주들은 V. ichthyoenteri 참조 균주와 99.1 ~ 100% 동일하였으며 V. ichthyoenteri는 3개 이상의 PCR products를 보였다. 이들 각각에 대한 tRNA type을 분석한 결과, no-tRNA, tRNAGlu(TTC) type 그리고 tRNAIle(GAT)와 tRNAAla(TGC) 를 coding하는 3 가지 tRNA type을 밝혔다.

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.276-286
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• 2020

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. This study was conducted for the isolation of potential lactic acid bacteria (LAB) with probiotic properties from goat milk and yogurt. Several tests were conducted in vitro using the standard procedures for evaluating the inhibitory spectra of LAB against pathogenic bacteria; tolerance to NaCl, bile salt, and phenol; hemolytic, milk coagulation, and bile salt hydrolase activities; gastrointestinal transit tolerance; adhesion properties; and antibiotic susceptibility. Among 40 LAB strains screened according to culture characteristics, five isolates exhibited antagonistic properties. Three were identified as Pediococcus acidilactici, and two were identified as Enterococcus faecium, exploiting 16S rRNA gene sequencing. All the isolates succeeded in the gastrointestinal transit tolerance assay and successively colonized mucosal epithelial cells. Based on the results of these in vitro assays, both P. acidilactici and E. faecium can be considered as potential probiotic candidates.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.340-342
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• 2005

한천분해 세균은 제주 연안의 해수로부터 분리되어졌다. 균주는 Gram 음성 간균이며, 절대 호기성 세균이다. 균주는 agarase를 생성하여 한천을 분해하는 것으로 관찰되었다. 균주의 생화학적 특성과 16S rRNA 유전자 염기서열 분석한 결과 Agarivorans속으로 동정 되었다. 그래서 Agarivorans sp. JA1이라 명명하였다. agarase의 최적 생산을 위한 agar농도는 0.5%이며, pH, 온도와 NaCl 농도는 각각 pH 7, $25^{\circ}C$ $^{\sim}$ $30^{\circ}C$와 2%였다. 유기태과 무기태는 각각 yeast extract와 $NaNO_3$를 첨가 할 경우 agarase 생성이 가장 좋은 것으로 사료되었다. Agarase의 최적 생산 활성 측정은 DNS법(3,5-dinitrosalicyclic acid procedure)을 이용하여 환원당 값을 산출하였고, 50000(U/L)이상 나왔다.