• 한국미생물·생명공학회지
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• 제20권6호
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• pp.681-686
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• 1992

D,L-ATC의 L-cysteine으로의 생물학적 전환에 있어 균체를 이용할 때, 계면활성제의 영향, 효소의 안정성 및 연속생산공정중의 고정화 균체 반응기의 안정성에 대하여 분석하였다. 계면활성제의 첨가없이 균체만을 이용할 때 반응은 매우 미미하게 이루어졌으나 SDS와 Triton X-100을 첨가할 때 cell-free 조효소액을 이용하는 경우와 비슷한 정도의 결과가 얻어졌다. 효소 활성은 $30^{\circ}C$에서 7시간 저장후 50 저하되었으며 질소가스하의 혐기적인 조건에서는 활성저하가 거의 일어나지 않았다. 이와 같은 효소의 불활성화는 효소에 대한 산소의 작용으로 사료되었다. 그러나, alginate로 고정화한 균체를 이용한 연속반응공정에서 혐기적으로 조건하에서 150시간 내에 대부분의 활성을 잃어버렸으며, L-cysteine 저해제인 hydroxylamine을 첨가할 때 효소활성이 급속히 감소되었다.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.52-57
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• 2007

Growth promotion of wild plants by some plant growth-promoting rhizobacteria (PGPR) was examined in the microcosms composed of soils collected separately from a grass-covered site and a nongrass-covered site in a lakeside barren area at Lake Paro, Korea. After sowing the seeds of eight kinds of wild plants and inoculation of several strains of PGPR, the total bacterial number and microbial activity were measured during 5 months of study period, and the plant biomasses grown were compared at the end of the study. Acridine orange direct counts in the inoculated microcosms, $1.3-9.8{\times}10^9\;cells{\cdot}g\;soil^{-1}$ in the soil from the grass-covered area and $0.9-7.2{\times}10^9\;cells{\cdot}g\;soil^{-1}$ in the soil from the nongrass-covered site, were almost twice higher than those in the uninoculated microcosms. The number of Pseudomonas sp., well-known bacteria as PGPR, and the soil dehydrogenase activity were also higher in the inoculated soils than the uninoculated soils. The first germination of sowed seeds in the inoculated microcosm was 5 days earlier than the uninoculated microcosm. Average lengths of all plants grown during the study period were 26% and 29% longer in the inoculated microcosms starting with the grass-covered soil and the nongrass-covered soil, respectively, compared with those in the uninoculated microcosms. Dry weights of whole plants grown were 67-82% higher in the inoculated microcosms than the uninoculated microcosms. Microbial population and activity and growth promoting effect by PGPR were all higher in the soils collected from the grass-covered area than in the nongrass-covered area. The growth enhancement of wild plants seemed to occur by the activities of inoculated microorganisms, and this capability of PGPR may be utilized for rapid revegetation of some barren lands.

• 한국토양비료학회지
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• 제44권2호
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• pp.236-241
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• 2011

경남지역 과수원 토양 25개소를 대상으로 2010년에 토양 화학성분과 미생물 다양성을 검토하고 토성, 지형 및 작물별 주요 변동요인을 주성분분석으로 해석하였다. 토양 유효인산 및 치환성 칼륨 함량은 적정수준 보다 각각 2.6배 및 2.3배 높았으며 대부분 토양 화학성분의 최소값과 최대값 차이가 크게 나타났다. 지형적으로 산록경사지는 토양 유효인산 함량이 유의적으로 높았고 (p<0.05) 미사질양토에서 곰팡이와 형광성 슈도모나스균 개체수가 사양토 보다 유의적으로 높았다 (p<0.05). 주성분 분석결과 제 1주성분이 28.4%, 제 2주성분이 20.1%로서 전체 48.5%의 자료를 설명할 수 있었으며 제 1주성분은 토양의 세균 개체수가 가장 크게 기여하였다. 토양 유기물 함량은 곰팡이 개체수와 정의상관을 보인 반면 세균 개체수와 부의상관을 나타냈다.

• Preventive Nutrition and Food Science
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• 제9권2호
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• pp.138-143
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• 2004

Soybean curd residues (SCR) obtained from hot and cold manufacturing processes were fermented by indigenous microorganisms, Lactobacillus rhamnosus LS and Bacillus firmus NA-l for 15 h at 37$^{\circ}C$. The pH, acidity, viable cell counts, and tyrosine content were evaluated in samples with variations in sugar, starter and type of SCR. The raw Doowon SCR (D-SCR, cold-processed) fermented by indigenous microorganism had a 0.9% acidity and 6.7 ${\times}$ 10$^{7}$ CFU/g viable cell counts, compared with the 0.11 % acidity and 6.7 ${\times}$ 10$^{6}$ CFU/g viable cell counts of raw fermented Pulmuwon SCR (P-SCR, hot-processed). After fermentation of raw P-SCR with 1 % glucose and 1 % L. rhamnosus LS starter, the viable cell counts, tyrosine content and acidity were 4.7 ${\times}$ 10$^{8}$ CFU/g, 16.3 mg% and 0.9%, respectively. In addition, the raw P-SCR fermented with Bacillus firmus NA-l as co-starter had a 0.45% acidity, 2.4 ${\times}$ 10$^{8}$ CFU/g lactic acid bacteria, and 3.3 ${\times}$ 10$^{6}$ CFU/g Bacillus sp. In particular, the tyrosine content was increased 5 fold. The drying of fermented SCR was completed by hot-air drying (5$0^{\circ}C$) within 12 h; the dried P-SCR and D-SCR had 1.8 ${\times}$ 10$^{7}$ CFU/g and 5.3 ${\times}$ 10$^{6}$ CFU/g viable cell counts, respectively. The concentrate of methanol extract from fermented D-SCR inhibited the initial cell growth of E. coli, Staphylococcus aureus and Pseudomonas aeruginosa in liquid culture.

• Journal of Microbiology and Biotechnology
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• 제19권1호
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• pp.42-50
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• 2009

Fifty-four Pectobacterium carotovorum subsp. carotovorum strains isolated in Korea were characterized by a spectrum of antibacterial activities against 7 indicator strains chosen to represent various regions and host plants. All P. carotovorum subsp. carotovorum isolates tested could be grouped into 4 classes depending on the pattern of antibacterial substance production. All tested strains had DNA fragment(s) homologous to the genes encoding carotovoricin and 21 of them had genes homologous to DNA invertase. Sixteen strains had genes homologous to the genes encoding carocin S1. Several isolates produced antibacterial substances active against strains in Brenneria, Pantoea, and Pectobacterium genera that belonged formerly to the genus Erwinia. Strains in Pseudomonas or Xanthomonas sp. were not sensitive to the antibacterial substances produced by P. carotovorum subsp. carotovorum, except for X. albilineans that was sensitive to antibacterial substances produced by most strains in P. carotovorum subsp. carotovorum and P. betavasculorum KACC10056. These results demonstrated the diverse patterns of antibacterial substance production and the possibility of the existence of new antibacterial substance(s) produced by P. carotovorum subsp. carotovorum isolated in Korea.

• Natural Product Sciences
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• 제23권3호
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• pp.151-156
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• 2017

A phytochemical study of Alphonsea cylindrica King (unreported) has led to the isolation of six alkaloids. The compounds were identified as kinabaline (1; azafluorenone alkaloid), muniranine (2), O-methylmoschatoline (3; oxoaporphine alkaloid), lysicamine (4), atherospermidine (5) and N-methylouregidione (6; 4, 5-dioxoaporphine alkaloid). The structures of the isolated compounds were determined based on the spectroscopic techniques and by comparison with data reported in the literature. Alkaloid 2 was isolated as a new derivative of azafluorenone while alkaloids 1, 3 - 6 were isolated for the first time from Alphonsea species. In addition, alkaloid 3 and 4 showed inhibition zone against Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus in disc diffusion test. The minimum inhibition concentration (MIC) values of lysicamine (4) against S. aureus, B. cereus and P. aeruginosa were found to be smaller than O-methylmoschatoline (3). Therefore, the reported antibacterial activity showed the potential of this plant as natural antibacterial agent and supported the documented traditional use of Alphonsea sp. in the treatment of diarrhea and fever.

• 미생물학회지
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• 제29권6호
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• pp.392-396
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• 1991

Pseudomonas sp. DJ77의 chromosomal DNA로부터 6.9kb XhoI 절편 상에 존재하는 phenanthrene 분해에 관련된 유전자군을 vector pBLUESCRIPT SK(+)에 클로닝하였다. 이렇게 얻은 재조합 plasmid인 pHENX7을 가지고 있는 JM101 균주는 3-methylcarechol을 노란색의 meta-cleavage 화합물로 전환할 수 있었다. 그러나 삽입된 절편의 방향이 반대가 되도록 제조한 pHENX7은 extradiol dioxygenase 활성을 나타내지 않기 때문에 전사방향을 알 수 있었다. pHENX7과 이의 듀도체들을 지니는 JH101균주에서 PhnC(24kDa), PhnD(31KDa), PhnE(34kDa), PhnF(KDa)의 4 polypeptide를 확인 할 수 있었고 개개의 유전자의 위치와 범위를 알 수 있었다. 유전자 순서는 phnC-phnD-phnE-phnF-phnG이었으며, phnC, phnD, phnE, phnF, phnG는 각기 glutathione S-transferase, meta-cleavage compound hydrolase extradiol dioxygenase, meta-cleavage compound dehydrogenase의 유전자이었다.

• 대한약침학회지
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• 제20권1호
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• pp.18-22
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• 2017

Objectives: The current investigation was carried out to determine the cytotoxic and the antimicrobial activities of methanolic extracts of Plumbago zeylanica. Methods: The stems, leaves, and whole plants were air dried and extracted with methanol by using a Soxhlet extractor for 72 hours at $55-60^{\circ}C$. The antimicrobial activities were determined from the zones of inhibition, which were measured by using the agar well diffusion method, and the cytotoxicity assays were performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method. Results: The methanolic extracts of the stem and the leaves of Plumbago zeylanica were tested against six bacterial species and nine fungal species, and both extracts showed antimicrobial activity in a dose-dependent manner. The leaf extract of Plumbago zeylanica showed maximum antimicrobial activity against both Staphylococcus aureus sub sp aureus and Fusarium oxysporum. The stem extract was found to be more antimicrobial against the Pseudomonas aeruginosa and the Penicillium expansum species. MTT assays were used to test the cytotoxicity of the whole plant extract in the HCT-116 and the K-562 cell lines, and that extract was shown to have weak cytotoxicity in both cell lines. Conclusion: In the present study, the methanolic stem extracts of Plumbago zeylanica were found to possess remarkable antibacterial activities against many human and agricultural pathogens. The extracts were also found to possess significant antifungal activities, but the antifungal activities were less than the antibacterial activities. Finally, the extracts were found to have weak cytotoxicities in the HCT-116 and the K-562 cell lines.

• 미생물학회지
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• 제33권3호
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• pp.181-186
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• 1997

유기용매계에서 lipase AK를 사용하여 당 ester화합물을 합성하였다. 유기용매로는 당의 용해도가 높고 반응성이 뛰어난 pyridine을, acyl donor로는 vinyl butyrate을 선택하였다. Transesterification반응에 의해 생성된 monobutyryl fructose와 dibutyryl fructose는 TLC 및 GC 분석으로 확인하였다. Transesterification에 미치는 반응조건은 fructose:vinyl butyrate의 비가 1:10(M/M), 반응온도 40^{\circ}C.$, 교반속도 150rpm, 효소량 10mg/ml의 경우가 적당하였으며 반응시간이 길어질수록 전환율이 높아져, 반응 10일 정도에서 전환율은 90% 이상에 도달하였다. 이때 반응 초기에는 monobutyryl fructose가 주로 합성되었으나 시간이 경과함에 따라 dibutyryl fructose의 함량비가 증가하였다. 반응계에 소량의 수분을 첨가하였을 경우에는 반응속도가 감소함과 동시에 반응산물중 dibutyryl fructose의 양은 줄어들고 monobutyryl fructose의 생성량이 증가하는 경향을 보여주었으며, 수분함량 1%에서는 monobutyryl fructose만이 생성되었다.

• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.97-105
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• 2014

Quorum quenching (QQ) with a microbial vessel has recently been reported as an economically feasible biofouling control platform in a membrane bioreactor (MBR) for wastewater treatment. In this study, a quorum quenching MBR with a ceramic microbial vessel (CMV) was designed to overcome the extremely low F/M ratio inside a microbial vessel. The CMV was prepared with a monolithic ceramic microporous membrane and AHL-degrading QQ bacteria, Pseudomonas sp. 1A1. The "inner flow feeding mode" was introduced, under which fresh feed was supplied to the MBR only through the center lumen in the CMV. The inner flow feeding mode facilitated nutrient transport to QQ bacteria in the CMV and thus enabled relatively long-term maintenance of cell viability. The quorum quenching effect of the CMV on controlling membrane biofouling in the MBR was more pronounced with the inner flow feeding mode, which was identified by the slower increase in the transmembrane pressure as well as by the visual observation of a biocake that formed on the used membrane surface. In the QQ MBR with the CMV, the concentrations of extracellular polymeric substances were substantially decreased in the biocake on the membrane surface compared with those in the conventional MBR. The CMV also showed its potential with effective biofouling control over long-term operation of the QQ MBR.