• 한국작물학회지
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• 제51권spc1호
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• pp.247-250
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• 2006

본 연구는 polyamine이 쪽 모상근 배양에서 뿌리의 생장과 indigo 생합성에 미치는 영향을 조사하였다. 1. 토양미생물인 Agrobacterium rhizogenes R1000을 이용하여 쪽 자엽으로부터 모상근을 효과적으로 유도하여 배양하였다. 2. 모상근 생장과 인디고 생합성이 polyamines(putrescine, spaermidine, spermine) 처리에 의하여 향상되었으며, 그 중 putrescine이 다른 polyamines에 비하여 효과적이었다. 3. Putrescine 70 mg/l 처리가 모상근의 생육(4.4 g/flask)과 인디고 생합성(216.3 ug/g)의 향상에 최적조건으로 조사되었다.

• 한국식품과학회지
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• 제43권2호
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• pp.240-242
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• 2011

액체배양한 송이버섯 균사체와 배양액의 tyrosianse 억제활성과 melanocyte에서의 세포독성 및 멜라닌 생성억제효과를 검정한 결과 배양액 농축물은 큰 효과가 없었으나 송이버섯 균사체 추출물은 100 ppm에서 38.6%의 tyrosianse 억제활성을 나타내었을 뿐만 아니라 melan-a 세포에서 세포독성 없이 세포생존율 대비 19%의 멜라닌 생성량을 감소시켰다. 따라서 배양된 송이버섯균사체는 피부색소조절을 위한 소재로써 사용되어질 수 있는 큰 가능성을 가지고 있다고 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.668-671
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• 2007

A numerical study was conducted on a simplified model of a high-temperature solar receiver which incorporates liquid-metal heat pipe. The objective of this paper is to compare the isothermal characteristics of the heat pipe receiver with the conventional receiver utilizing convection of molten salt as heat carrier. The solar receiver was assumed to be subject to a concentration ratio between 50 and 1,000 to supply high-temperature heat to a stirling engine for electric power generation. For simplicity of the analysis, a cylindrical geometry was assumed and typical dimensions were used based on available literature. The heat pipe had a shape of double-walled cavity and the working fluid was a sodium. The analysis was performed assuming that the radiation heat flux on the inner walls of the receiver was uniform, since the focus of this study was laid on the comparison of the conventional type and heat pipe type receiver. The results showed that the heat pipe type exhibited superior performance when the operating temperature becomes higher. In addition, to explore the advantage of the heat pipe receiver, the channel shape and dimensions should be adjusted to increase the heat transfer area between the wall and the heat trnasfer medium.

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.314-322
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• 2018

Bacillus subtilis 8 is highly efficient at degrading feather keratin. We observed integrated feather degradation over the course of 48 h in basic culture medium while studying the entire process with scanning electron microscopy. Large amounts of ammonia, sulfite, and $\text\tiny{L}$-cysteic acid were detected in the fermented liquid. In addition, four enzymes (gamma-glutamyltranspeptidase, peptidase T, serine protease, and cystathionine gamma-synthase) were identified that play an important role in this degradation pathway, all of which were verified with molecular cloning and prokaryotic expression. To the best of our knowledge, this report is the first to demonstrate that cystathionine gamma-synthase secreted by B. subtilis 8 is involved in the decomposition of feather keratin. This study provides new data characterizing the molecular mechanism of feather degradation by bacteria, as well as potential guidance for future industrial utilization of waste keratin.

• Journal of Applied Biological Chemistry
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• 제48권4호
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• pp.183-186
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• 2005

Arabidopsis AHL gene encodes a 3'(2')-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase that plays a role in the sulfate activation pathway. We complemented E. coli cysQ mutant defective in cysteine biosynthesis with the AHL gene. AHL cDNA was cloned into the prokaryotic expression vector pKK388-1 and transformed into the bacterial mutant. Since cysQ mutant is a leaky cysteine auxotroph only under aerobic conditions, the bacteria were grown in liquid media with vigorous shaking to provide more aeration. In cysteine-free medium, cysQ mutant and the mutant harboring empty vector did not grow well, whereas cells harboring AHL cDNA exhibited significantly improved growth with doubling time of approximately 3 h. cysQ is known to encode a 3'(2'),5'-diphosphonucleoside 3'(2')-phosphohydrolase (DPNPase). However, our data suggest that cysQ protein has PAP-specific phosphatase activity in addition to DPNPase activity. Microbial complementation procedure described in this paper is useful for structure-activity studies of PAP-specific phosphatases identified from microbes and plants.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.236-242
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• 1995

Biological control of soilborne plant pathogens by the addition of antagonistic microorganisms to the soil may offer a practical supplement or alternative to existing disease management strategies that depend heavily on chemical pesticides. Soil amendment with antagonistic microbes was non-effective because of high cost, low efficacy, and inconvenient usage on the treatment course. Therefore, seed coating formulation for the application of biological seed treatments has been being to apply successful disease suppression for many important crops. The objectives of this study were to investigate the optimal condition for the spore production of biocontrol agent Bacillus subtilis YBL-7 and the liquid coating formulation that contained a suspension of a proper aqueous binder, as well as a ground fine solid particulate material. The maximum yield has been obtained from 60 hrs-old culture at 30$\circ$C in spore forming (SF) medium containing 0.8% nutrient broth, 0.05% yeast extract, 10$^{-1}$ M MgCl$^{2}$, 10$^{-4}$ M MnCl$^{2}$, 10$^{-5}$ M dipicolinic acid, and pH 6.5. The optimal condition of dried spore preparation was achieved when cells of B. subtilis YBL-7 was heat-dried with 50$\circ$C for 2 hrs.

• 한국축산식품학회지
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• 제36권4호
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• pp.487-493
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• 2016

The antimicrobial activity of bovine lactoferrin hydrolysates (bLFH) was measured against Pseudomonas strains (P. syringae and P. fluorescens) in vitro. To compare susceptibility to bLFH, minimal inhibitory concentration (MIC) values were determined using chemiluminescence assays and paper disc plate assays. Antimicrobial effect against P. fluorescens was not observed by either assay, suggesting that bLFH did not exhibit antimicrobial activity against P. fluorescens. However, a significant inhibition of P. syringae growth was observed in the presence of bLFH. The addition of bLFH in liquid or solid medium inhibited growth of P. syringae in a dose-dependent manner. Furthermore, a bLFH peptide with antimicrobial activity toward P. syringae was isolated and identified. The N-terminal amino acid sequences of thus obtained antimicrobial bLFH peptides were analyzed by a protein sequencer and were found to be Leu-Arg-Ile-Pro-Ser-Lys-Val-Asp-Ser-Ala and Phe-Lys-Cys-Arg-Arg-Trp-Gln-Trp-Arg-Met. The latter peptide sequence is known to be characteristic of lactoferricin. Therefore, in the present study, we identified a new antimicrobial peptide against P. syringae, present within the N-terminus and possessing the amino acid sequence of Leu-Arg-Ile-Pro-Ser-Lys-Val-Asp-Ser-Ala.

• 한국미생물·생명공학회지
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• 제27권2호
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• pp.118-123
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• 1999

A bacterial strain, designated T116, degrading terephthalic acid (TPA) was isolated from the soil around Taegu industrial area into which dye works wastewater flow. The isolate was identified as pseudomonas sp. based on its morphological and physiological characteristics. Degradation of TPA by the strain T116 was confirmed with UV scanning and HPLC. About 90% and 98% of TPA were degraded after 36 and 60 hours, respectively, during the culture in a liquid medium containing 0.1% TPA. Addition of KH2PO4 at a final concentration of 100ppm enhanced the chemical oxygen demand (COD) removal rate about 50% from dye works wastewater by Pseudomonas sp. T116. Optimum pH and temperature for COD reduction from wastewater were 7.0 and 3$0^{\circ}C$, respectively. The bacterium was applied to the continuous culture for the treatment of dye works wastewater whose TPA concentration and CODMn were 2,200ppm and 1,620ppm, respectively. It was observed that 90-95% of COD was eliminated after 4 days culture in the continuous culture with a retention time of 37 or 47 hours.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1279-1283
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• 2009

Garlic has been used for condiments and also for medicines to cure various diseases since ancient times. Many studies on the processing of garlic have been published, however, few of them were related with fermentation because of the antimicrobial action of the garlic. In this study, to conduct garlic fermentation, 4 lactic acid bacteria (LAB) strains with growth abilities in garlic medium were selected. Addition of various nitrogen, carbon, and mineral sources generally did not improve the growth of experimental strains during garlic fermentation except for Lactobacillus casei KFRI 704 by yeast extract and Lactococcus lactis subsp. cremoris ATCC 19257 by mineral sources. High performance liquid chromatography (HPLC) analysis of 32 phenolic compounds during fermentation showed that formononetin was decreased time dependently. The concentrations of volatile compounds and alliin did not change during fermentation. The results of this study would provide the basic understanding of garlic fermentation by selected strains of LAB.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.518-521
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• 1999

Bacillus sp. 79-23 spores were irradiated with $^{60}Co$ gamma-rays at doses ranging from 0.5 to 5 kGy. Following gamma-irradiation, seven mutant strains were isolated by scoring the halo sizes formed around the colonies grown on LB agar plates containing 4% carboxymethylcellulose (CMC) and trypan blue. The mutant strains showed a 1.5 to 2-fold increase in carboxymethylcellulase (CMCase) activity over the parent strain. Wheat bran acted as an effective inducer for CMCase production in the parent and mutant strains. Mutant strains 68 and 70 were identified as exhibiting higher CMCase activities than those of other mutants in LB media both with and without 3% wheat bran. In addition, these strains seem to produce substantially lower amounts of capsular materials, whereas the parent strain produced large amounts of them in both liquid and solid LB media. In flask cultures, the CMCase production by mutants 68 and 70 reached maximum levels of 17.5 unit/ml and 15.7 unit/ml, respectively, in an LB medium containing 3% wheat bran.