• 한국미생물·생명공학회지
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• 제38권3호
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• pp.322-328
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• 2010

발효홍어(홍어회)에 존재하는 박테리아 집단의 다양성을 확인하기 위해, 박테리아의 16S rDNA 절편들을 증폭하고 클로닝하여 라이브러리를 구축하였다. 삽입 서열의 염기서열을 결정한 후, BLAST 분석에 의해 미생물 동정을 하였다. 동일한 삽입서열 빈도를 계산하였을 때, 발효홍어(홍어회)에는 uncultured bacterium clone 054E11.b가 57.1% 나타남으로써 우점균으로 존재하고 있다고 추정하였다. 또한 발효홍어(홍어회) 현탁액을 한천배지에 도말하여 형성된 집락을 콜로니 PCR을 수행하였을 때, Pseudomonas sp. KC-EPS13 등 12 종의 박테리아가 동정되었다. 배양 의존적 방법과 배양 비의존적 방법으로 홍어회를 분석하였을 때, Psychrobacter sp. J466만이 두 가지 방법에서 모두 검출되었고 나머지 박테리아들의 균총은 상이하였다.

• 전기전자학회논문지
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• 제27권1호
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• pp.116-121
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• 2023

본 논문에서는 딥러닝 예측 결과 정보를 적용하는 복합 미생물 배양기를 위한 딥러닝 구조를 개발한다. 제안하는 복합 미생물 배양기는 수집한 복합 미생물 데이터에 대해 복합 미생물 데이터 전처리, 복합 미생물 데이터 구조 변환, 딥러닝 네트워크 설계, 설계한 딥러닝 네트워크 학습, 시제품에 적용되는 GUI 개발 등으로 구성된다. 복합 미생물 데이터 전처리에서는 미생물 배양에 필요한 당밀, 영양제, 식물엑기스, 소금 등의 양에 대해 원-핫 인코딩을 실시하며, 배양된 결과로 측정된 pH 농도와 미생물의 셀 수에 대해 최대-최소 정규화 방법을 사용하여 데이터를 전처리한다. 복합 미생물 데이터 구조 변환에서는 전처리된 데이터를 물 온도와 미생물의 셀 수를 연결하여 그래프 구조로 변환 후, 인접 행렬과 속성 정보로 나타내어 딥러닝 네트워크의 입력 데이터로 사용한다. 딥러닝 네트워크 설계에서는 그래프 구조에 특화된 그래프 합성곱 네트워크를 설계하여 복합 미생물 데이터를 학습시킨다. 설계한 딥러닝 네트워크는 Cosine 손실함수를 사용하여 학습 시에 발생하는 오차를 최소화하는 방향으로 학습을 진행한다. 시제품에 적용되는 GUI 개발은 사용자가 선택하는 물 온도에 따라 목표하는 pH 농도(3.8 이하) 복합 미생물의 셀 수(10⁸ 이상)를 배양시키기 적합한 순으로 나타낸다. 제안된 미생물 배양기의 성능을 평가하기 위하여 공인시험기관에서 실험한 결과는, pH 농도의 경우 평균 3.7로, 복합 미생물의 셀 수는 1.7 × 10⁸으로 측정되었다. 따라서, 본 논문에서 제안한 딥러닝 예측 결과 정보를 적용하는 복합 미생물 배양기를 위한 딥러닝 구조의 효용성이 입증되었다.

• 한국미생물·생명공학회지
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• 제20권6호
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• pp.687-692
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• 1992

혼합배양중의 각 미생물의 생균수 측정은 순수배양보다 훨씬 복잡하다. 특히 두 균주의 크기가 비슷한 경우에는 사용할 수 있는 방법이 더 제한된다. 본 연구에서는 두 균의 크기가 비슷한 경우에도 적용될 수 있는 간단한 생균수 측정방법을 개발하였다. 미생물 배양액의 산소흡수속도(OUR)는 세포수에 비례하며 이때의 비례상수인 최대 비산소흡수속도( maximum specific OUR)를 알고 있으면 배양액의 OUR을 측정함으로써 간접적으로 생균수를 구할 수 있게된다. 혼합배양의 경우 산소흡수속도는 각 미생물의 호흡속도의 합이 되며, 각 미생물의 호흡속도가 서로 다르고 또한 온도의존성이 다르다면 호흡속도의 측정을 이용하여 각 생균수를 간접적으로 측정할 수 있다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.93.2-94
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• 2003

In our previous studies, we selected three antagonistic bacteria, KJ1R5, KJ2C12, and KJ9C8 against Phytophthora capsici, the casual agent of Phytophthora blight of pepper. For elucidating production, root colonization, and total microbial activity were investigated. The dual culture assay was accomplished to elucidate existence of antibiotics. In this assay, any antagonistic bacteria did not inhibit growth of six important fungal plant pathogens, suggesting that these antagonists do not produce antibiotics. root surface or rhizosphere soil colonizations were examined with spontaneous rifampicin-resistant mutants equal to antagonistic ability of wild types. KJ2C12 colonized consistently rhizosphere soil while yellowish colonies of KJ1R5 and KJ9C8 well colonized root surfaces and rhizosphere soil. Total microbial activity in pots treated with the antagonistic bacteria was measured using fluorescein diacetate hydrolysis. total microbial activity of three antagonistic bacteria treatments was significantly higher than that of buffer-treated control until 4days after treatment. However, total microbial activity of treatment of three antagonistic bacteria decreased after 7 days. These results indicate that the antagonistic bacteria, KJ1R5 and KJ9C8 colonized and protected roots well against Phytophthora blight of pepper through competition of infection courts, especially competitions.

• 분석과학
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• 제10권2호
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• pp.146-152
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• 1997

미생물막 전극을 이용하여 신속하게 생화학적 산소요구량(BOD)을 측정할 수 있는 신속 BOD 측정장치를 개발하였다. 미생물의 배양과 미생물막의 제조방법, BOD 측정시 시료 용액의 흐름속도의 영향, 용액의 pH의 영향, 그리고 미생물막의 감응특성 등에 관하여 연구하였다. 본 연구에서 개발한 신속 BOD 측정장치는 개인용 컴퓨터에 연결되어 BOD 측정의 전 과정이 자동으로 진행되도록 제작되었으며, 시료 용액의 유속이 7.8mL/min일 때 시료 주입 5분 후의 측정시에 좋은 결과를 나타내었다.

• The Journal of Advanced Prosthodontics
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• 제3권1호
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• pp.20-24
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• 2011

PURPOSE. The aim of this study was to identify in vitro antimicrobial activity of the tissue conditioner containing silver nanoparticles on microbial strains, Staphylococcus aureus, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS. Experimental disc samples ($20.0{\times}3.0$ mm) of tissue conditioner (GC Soft-Liner, GC cooperation, Tokyo, Japan) containing 0.1 - 3.0% silver nanoparticles (0%: control) were fabricated. Samples were placed on separate culture plate dish and microbial suspensions (100 ${\mu}L$) of tested strains were inoculated then incubated at $37^{\circ}C$. Microbial growth was verified at 24 hrs and 72 hrs and the antimicrobial effects of samples were evaluated as a percentage of viable cells in withdrawn suspension (100 ${\mu}L$). Data were recorded as the mean of three colony forming unit (CFU) numerations and the borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS. A 0.1% silver nanoparticles combined to tissue conditioner displayed minimal bactericidal effect against Staphylococcus aureus and Streptococcus mutans strains, a 0.5% for fungal strain. Control group did not show any microbial inhibitory effect and there were no statistical difference between 24 hrs and extended 72 hrs incubation time (P > .05). CONCLUSION. Within the limitation of this in vitro study, the results suggest that the tissue conditioner containing silver nanoparticles could be an antimicrobial dental material in denture plaque control. Further mechanical stability and toxicity studies are still required.

• Asian-Australasian Journal of Animal Sciences
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• 제25권7호
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• pp.1045-1054
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• 2012

The phylogenetic diversity of the bacteria in hot composting samples collected from three spatial locations was investigated by molecular tools in order to determine the influence of gradient effect on bacterial communities during the thermophilic phase of composting swine manure with rice straw. Total microbial DNA was extracted and bacterial near full-length 16S rRNA genes were subsequently amplified, cloned, restriction fragment length polymorphism-screened and sequenced. The superstratum sample had the highest microbial diversity among the three samples which was possibly related to the surrounding conditions of the sample resulting from the location. The results showed that the sequences related to Bacillus sp. were most common in the composts. In superstratum sample, 45 clones (33%) and 36 clones (27%) were affiliated with the Bacillus sp. and Clostridium sp., respectively; 74 clones (58%) were affiliated with the Clostridium sp. in the middle-level sample; 52 clones (40%) and 29 clones (23%) were affiliated with the Clostridium sp. and Bacillus sp. in substrate sample, respectively. It indicated that the microbial diversity and community in the samples were different for each sampling site, and different locations of the same pile often contained distinct and different microbial communities.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.36-40
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• 1995

Valistatin, a new inhibitor of aminopeptidase M(AP-M) was discovered in the culture broth of Streptomyces sp. SL20209 isolated from a soil sample. The inhibitor was purified by extraction with n-butanol and the various column chromatographies, and then isolated as whitish powder. The $^1 H-and ^1 H, ^1 H-COSY$ NMR studies, amino acid analysis, and fragmentation patterns by FAB-MS suggested the presence of one 3-amino-2-hydroxy-4-phenylbutanoic acid and two valine residues in the inhibitor. Thus, the structure of valistatin was determined as 3-amino-2-hydroxy-4-phenylbutanoyl-valyl-valine. Valistatin has the molecular formular $C_20H_31N_3 O_5$ (MW 394), and its $IC_50$ value against hog kidney AP-M was determined to be 3.12 $mu g/ml$.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권1호
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• pp.57-60
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• 2000

$(R)-\beta-acetylmercaptoisobutyric$ acid (RAM), a chiral compound, is an important intermediate for the chemical synthesis of various antihypertensive and congestive heart failure drugs. Microorganisms capable of converting $(R,S)-\beta-acetylmercaptoisobutyric$ acid ((R,S)-ester) to RAM were screened from soil microorganisms. A strain of Pseudomonas sp. 1001 screened from a soil sample was selected to be the best. Cells showed an activity of 540 U/mL from culture broth and the enzyme was thermostable up to $70^{\circ}C$. This strain could produce RAM asymmetrically from (R,S)-ester.

• Journal of Applied Biological Chemistry
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• 제58권3호
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• pp.209-218
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• 2015

Fructooligosaccharides have been mainly produced by microbial fructosyltransferases (FTase) enzymes. The present work focuses on the optimization of medium composition and cultivation parameters affecting FTase produced by Penicillium aurantiogriseum AUMC 5605 in shake flask cultivation. FTase production was optimized in two steps using DeMeo's fractional factorial design. A 1.46-fold increase in FTase production (105.4 U/mL) was achieved using the optimized culture medium consisting of (g/L): sucrose, 600; yeast extract, 10; $K_2HPO_4$, 5; $MgSO_4{\cdot}7H_2O$, 0.5; $(NH_4)_2SO_4$, 1.0 and KCl, 0.5. The obtained results showed that the maximum FTase enzyme activity was produced at initial cultivation pH values ranging from 6.0-6.5, at agitation speed of 200 rpm and using vegetative fungal cells as inoculum. Moreover, results showed that optimization of medium composition and some cultivation parameters resulted in an increase of about 93.7% in the enzyme activity than the nonoptimized cultivation conditions after 96 h of cultivation. Additionally, maximum production and specific production rates recorded 2340 U/L/h and 102 U/L/h/g cells, respectively.