• 한국식품영양학회지
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• 제10권3호
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• pp.344-349
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• 1997

Bacillus sp. DSNC 101은 탄소원으로 2.0% oat spelts xylan, 질소원으로 2.0% yeast extract, 그리고 인산염으로 0.4% K2HPO4를 함유한 pH 8.0의 xylanase 생산 배지에서 4$0^{\circ}C$에서 3일간 배양하였을 때 305.0 unit/ml의 xylanase 활성도를 나타내었다. 본 균주는 xylan, 가용성 전분, 볏짚 분말, Avicel, maltose, 그리고 lactose를 유일한 탄소원으로 사용하였을 때 xylanase를 생산하였으나 glucose, xylose, 그리고 arabinose를 사용하였을 때는 xylanase를 생산하지 않았다. 여러 가지 기질들에 대한 배양 상징액의 분해 활성을 조사한 바, xylan 분해 활성 외에 Avicel, carboxymethyl cellulose, 그리고 전분 및 PNPX에 대한 분해 활성은 나타내지 않았다. Xylanase 합성은 glucose에 의해서는 억제되었으나 xylose에 의해서는 억제되지 않았다. 배양 상징액을 이용한 xylan 분해 산물은 xylobiose를 포함한 소당류들이었으며 xylose는 거의 생성되지 않았다.

• The Plant Pathology Journal
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• 제28권1호
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• pp.20-31
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• 2012

Endophytic bacterial communities of tidal flat plants antagonistic to oomycete plant pathogens were studied by the isolation of 256 root colonizing endophytic bacteria from surface-disinfected root tissues of six plants ($Rosa$ $rugosa$, $Suaeda$ $maritima$, $Vitex$ $rotundifolia$, $Carex$ $scabrifolia$, $Glehnia$ $littoralis$ and $Elymus$ $mollis$) growing in a tidal flat area of Namhae Island, Korea. To understand the antagonistic potential, an $in$ $vitro$ antagonistic assay was performed to characterize and identify strains that were antagonistic to the oomycete plant pathogens $Phytophthora$ $capsici$ and $Pythium$ $ultimum$ from the total population. Nine percent of the total number of isolated bacteria exhibited in vitro inhibitory activity against target plant pathogenic oomycetes. Taxonomic and phylogenetic placement of the antagonistic bacteria was investigated by analysis of the 16S rRNA gene sequences. The sequence analysis classified the antagonistic strains into four major classes of the domain bacteria ($Firmicutes$, ${\alpha}-Proteobacteria$, ${\gamma}-Proteobacteria$ and $Actinomycetes$) and 10 different genera. Further production of secondary metabolites, hydrolytic enzymes and plant growth promoting traits were determined for the putative new species of antagonistic endophytic bacteria. These new strains could not be identified as known species of ${\alpha}-Proteobacteria$, and so may represent novel bacterial taxa. The unexpected high antagonistic bacterial diversity associated with the tidal flat plants may be indicative of their importance in tidal flat plants as a promising source of novel antimicrobial compounds and biocontrol agents.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.155-160
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• 2005

Abstract A direct approach was used to retrieve active lipases from Paenibacillus polymyxa genome databases. Twelve putative lipase genes were tested using a typical lipase sequence rule built on the basis of a consensus sequence of a catalytic triad and oxyanion hole. Among them, six genes satisfied the sequence rule and had similarity (about 25%) with known bacterial lipases. To obtain the six lipase proteins, lipase genes were expressed in E. coli cells and lipolytic activities were measured by using tributyrin plate and pnitrophenyl caproate. One of them, contig 160-26, was expressed as a soluble and active form in E. coli cell. After purifying on Ni-NTA column, its detailed biochemical properties were characterized. It had a maximum hydrolytic activity at $30^{\circ}C$ and pH 7- 8, and was stable up to $40^{\circ}C$ and in the range of pH 5- 8. It most rapidly hydrolyzed pNPC$_6$ among various PNPesters. The other contigs were expressed more or less as soluble forms, although no lipolytic activities were detected. As they have many conserved regions with lipase 160-26 as well as other bacterial lipases throughout their equence, they are suggested as true lipase genes.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권1호
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• pp.43-51
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• 2002

The cloning and expression of $\beta-glucosidase$ II, encoded by the gene ${\beta}glu2$, from thermotolerant yeast Pichia etchellsii into Escherichia coli is described. Cloning of the 7.3 kb BamHI/SalI yeast insert containing ${\beta}glu2$ in pUC18, which allowed for reverse orientation of the insert, resulted in better enzyme expression. Transformation of this plasmid into E. coli JM109 resulted in accumulation of the enzyme in periplasmic space. At $50^{\circ}C$, the highest hydrolytic activity of 1686 IU/g protein was obtained on sophorose. Batch and fed-batch techniques were employed for enzyme production in a 14 L bioreactor. Exponential feeding rates were determined from mass balance equations and these were employed to control specific growth rate and in turn maximize cell growth and enzyme production. Media optimization coupled with this strategy resulted in increased enzyme units of 1.2 kU/L at a stabilized growth rate of $0.14\;h^{-l}$. Increased enzyme production in bioreactor was accompanied by formation of inclusion bodies.

• Animal cells and systems
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• 제8권4호
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• pp.307-312
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• 2004

Fast kinetics of transient pH changes and difference spectrum formation have been investigated following mixing of ADP/ATP with partially purified plasma membrane PM-ATPase of the pathogenic yeast Candida albicans in the presence of five nutrients: glucose, glutamic acid, proline, lysine, and arginine and two analogs of glucose: 2-deoxy D-glucose and xylose. Average $H^+$- absorption to release ratio, indicative of population of ATPase undergoing complete hydrolytic cycle, was found to be 0.27 for control. This ratio varied between 0.25 (proline) to 0.36 (arginine) for all other compounds tested, except for glucose. In the presence of glucose, $H^+$- absorption to release ratio was exceptionally high (0.92). While no UV difference spectrum was observed with ADP, mixing of ATP with ATPase led to a large conformational change. Exposure to different nutrients restricted the magnitude of the conformational change; the analogs of glucose were found to be ineffective. This suppression was maximal in the case of glucose (80%); with other nutrients, the magnitude of suppression ranged from 40-50%. Rate of $H^+$- absorption, which is indicative of E~P complex dissociation, showed positive correlation with suppression of conformational change only in the case of glucose and no other nutrient/analog. Mode of interaction of glucose with plasma membrane $H^+$-ATPase thus appears to be strikingly distinct compared to that of other nutrients/analogs tested. The results obtained lead us to propose a model for explaining glucose stimulation of plasma membrane $H^+$-ATPase activity.

• 한국균학회지
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• 제39권2호
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• pp.126-130
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• 2011

작물의 생육촉진 및 식물 진균병의 생물방제능을 동시에 나타내는 다기능성 미생물제제를 개발하고자 토양으로부터 분리하여 보관중인 세균 120종의 활성을 검토하였다. 그 중 siderophore를 생성하고 항진균 활성을 보이는 BS11-1, BS11-2, BS11-3를 선발하였다. 이들 균주는 cellulase, protease 같은 lytic enzyme을 생산하였으며 식물성장 촉진 호르몬중의 하나인 IAA를 생성하였다. 이들 선발균들에 의한 식물 생장 촉진을 조사한 결과, BS11-1, BS11-2, BS11-3 균 배양액 관주 시 고추 유묘의 생육을 132%, 122%, 120% 증가 시켰으며, BS11-1, BS11-2 균주의 경우 뿌리의 신장 및 생육이 촉진되었음을 확인 할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1559-1565
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• 2014

Cellulase and xylanase are main hydrolysis enzymes for the degradation of cellulosic and hemicellulosic biomass, respectively. In this study, our aim was to develop and test the efficacy of a rapid, high-throughput method to screen hydrolytic-enzyme-producing microbes. To accomplish this, we modified the 3,5-dinitrosalicylic acid (DNS) method for microwell plate-based screening. Targeted microbial samples were initially cultured on agar plates with both cellulose and xylan as substrates. Then, isolated colonies were subcultured in broth media containing yeast extract and either cellulose or xylan. The supernatants of the culture broth were tested with our modified DNS screening method in a 96-microwell plate, with a $200{\mu}l$ total reaction volume. In addition, the stability and reliability of glucose and xylose standards, which were used to determine the enzymatic activity, were studied at $100^{\circ}C$ for different time intervals in a dry oven. It was concluded that the minimum incubation time required for stable color development of the standard solution is 20 min. With this technique, we successfully screened 21 and 31 cellulase- and xylanase-producing strains, respectively, in a single experimental trial. Among the identified strains, 19 showed both cellulose and xylan hydrolyzing activities. These microbes can be applied to bioethanol production from cellulosic and hemicellulosic biomass.

• 한국환경농학회지
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• 제6권2호
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• pp.1-11
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• 1987

수도용(水稻用) 유기인계(有機燐系) 살충제중에서 조제형태(粗劑形態)로 널리 사용되는 Diazinon제와 Dursban제의 담수토양중(湛水土壤中)에서의 경시적(經時的) 분해(分解)정도를 비교(比較)하고, 아울러 살균(殺菌)과 비살균(非殺菌)토양을 비교하므로서 토양미생물(土壤微生物)에 의한 분해효과(分解效果)를 실험하였다. 아울러 두 약제의 분해대사산물을 GC/MS로 확인하였으며 중요한 결과는 아래와 같다. 1. 항온기(恒溫器$(30{\pm}1^{\circ}C)$)내에서 담수상태(湛水狀態)로 처리한 Diazinon제와 Dursban제의 경시적 변화는 비살균토양(非殺菌土壤)에서 보다 살균토양(殺菌土壤)에서 약 3배(培) 정도 지연되었으며, 따라서 미생물에 의한 분해를 확인할 수 있었다. 2. Diazinon제의 상용농도에서의 반감기는 2.2일이었으며, Dursban 제는 10.8일이었다. 상용농도의 3 배량 고농도 처리에서는 두 약제 모두 평균 1일정도 분해가 지연되었다. 3. Diazinon의 분해대사산물(分解代謝産物)로는 가수분해산물인 0, 0-diethyl phosphorothioate 와 이 화합물의 이량체(二量體)인 sulfotep, 그리고 monooxygenase 에 의한 분해대사물인 Diazoxon, 0,0-diethyl-0-[2-(1-hydroxy-1, 1-dimethyl)-6-methyl]-pyrimidinyl phosphorothioate 그리고 2-isopropyl-6-methyl-pyrimidine-4-one 이 확인되었으며, Dursban 제의 대사산물로는 0, 0-diethyl phosphorothioate 만이 확인되어 주로 esterase 에 의한 분해가 주대 대사경로라고 밝혀졌다.

• 한국의류학회지
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• 제32권6호
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• pp.911-917
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• 2008

본 연구는 폴리에스터 직물에 리파제 처리시 첨가제에 따른 수분특성 변화를 검토하였다. 활성제(염화칼슘) 및 비이온 계면활성제(Triton X-100) 첨가가 수분율, 접촉각, 흡수속도, 표면형태변화에 미치는 영향을 비교, 분석하였다. 연구결과, 리파제 처리된 폴리에스터 직물의 수분율은 비이온 계면활성제인 Triton X-100 첨가시 현저히 감소하는 것으로 나타났다. 그러나 리파제의 활성제로 알려진 염화칼슘 첨가 시 폴리에스터 직물의 수분특성은 다소 증가하는 것으로 나타났다. 특히 리파제 처리 시 염화칼슘이 10mM이상 첨가된 경우 폴리에스터 직물의 수분특성이 증가되었다. 리파제 처리된 폴리에스터 직물의 표면관찰 결과, 섬유표면에 생성된 보이드와 크랙이 폴리에스터 직물의 수분특성 증가에 영향을 미치는 것으로 확인되었다. 이상의 결과를 통해, 폴리에스터 직물에 리파제 처리시 Triton X-100은 리파제의 활성을 저해하고, 염화칼슘은 리파제의 활성을 다소 증가시키는 것을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제32권4호
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• pp.430-436
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• 2022

Platycosides, Platycodi radix (Platycodon grandiflorus root) saponins, are used as food supplements and exert diverse pharmacological activities. Deglycosylation of saponins enhances their biological efficacy, and deglycosylated platycosides are produced mainly through enzymatic hydrolysis. However, the types of available deglycosylated platycosides remain limited because of a lack of hydrolyzing enzymes that can act on specific glycosides in glycosylated platycosides. In this study, a crude enzyme from Aspergillus tubingensis converted platycoside E (PE) and polygalacin D₃ (PGD3) into deglucose-apiose-xylosylated (deGAX)-platycodin D (PD) and deGAX-polygalacin D (PGD), respectively. The products were identified through LC/MS analysis by specifically hydrolyzing all glucose residues at C-3, and apiose and xylose residues at C-28 of platycoside. The hydrolytic activity of the crude enzyme obtained after the cultivation of the fungus using citrus pectin and corn steep solid as carbon and nitrogen sources, respectively, in culture medium was increased compared with those using other carbon and nitrogen sources. The crude enzyme from A. tubingensis was the most effective in producing deGAX platycoside at pH 5.0 and 60℃. The crude enzyme produced 0.32 mg/ml deGAX-PD and 0.34 mg/ml deGAX-PGD from 1 mg/ml PE and 1 mg/ml PGD3 (at pH 5.0 and 60℃) for 12 and 10 h, with productivities of 32.0 and 42.5 mg/l/h and molar yields of 62.1 and 59.6%, respectively. To the best of our knowledge, this is the first study to produce deGAX platycosides from glycosylated platycosides.