• 한국미생물·생명공학회지
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• 제44권1호
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• pp.9-18
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• 2016

청국장에서 강력한 항균력을 지닌 2개의 Bacillus 균주들인 CJW15와 SSD8이 분리되었다. 16S rRNA와 recA 유전자들 염기서열 결정에 의해 두가지 균주 모두 B. amyloliquefaciens로 동정되었다. CJW15는 B. cereus ATCC14579, Listeria monocytogenes ATCC19111, Lactococcus lactis ATCC11454 들의 증식을 강력히 억제하며 SSD8은 B. cereus ATCC14579와 Enterococcus faecium ATCC19953 증식을 억제하였다. 두 균주들의 항균력은 $100^{\circ}C$, 15분 처리에도 감소하지 않았고 산성인 pH 3과 알칼리인 pH 12에서도 안정하였다. 트립신, 펩신, 프로테아제 K, 프로테아제 효소처리에 의해 CJW15 항균력은 변화가 없었지만 SSD8 항균력은 절반으로 감소하였다. 두 균주 공히 surfactin, fengycin, iturin, iturinA와 같은 lipopeptide 생합성 유전자들을 지니고 있고 subtilin과 같은 박테리오신 유전자들도 지니고 있다. 또 두 균주들은 혈전용해능을 지니고 있다.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.505-514
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• 2020

The symbiotic nature of the relationship between algae and marine bacteria is well-studied among the complex microbial interactions. The mutual profit between algae and bacteria occurs via nutrient and vitamin exchange. It is necessary to analyze the genome sequence of a bacterium to predict its symbiotic relationships. In this study, the genome of a marine bacterium, Pseudoruegeria sp. M32A2M, isolated from the south-eastern isles (GeoJe-Do) of South Korea, was sequenced and analyzed. A draft genome (91 scaffolds) of 5.5 Mb with a DNA G+C content of 62.4% was obtained. In total, 5,101 features were identified from gene annotation, and 4,927 genes were assigned to functional proteins. We also identified transcription core proteins, RNA polymerase subunits, and sigma factors. In addition, full flagella-related gene clusters involving the flagellar body, motor, regulator, and other accessory compartments were detected even though the genus Pseudoruegeria is known to comprise non-motile bacteria. Examination of annotated KEGG pathways revealed that Pseudoruegeria sp. M32A2M has the metabolic pathways for all seven vitamin Bs, including thiamin (vitamin B1), biotin (vitamin B7), and cobalamin (vitamin B12), which are necessary for symbiosis with vitamin B auxotroph algae. We also identified gene clusters for seven secondary metabolites including ectoine, homoserine lactone, beta-lactone, terpene, lasso peptide, bacteriocin, and non-ribosomal proteins.

• 미생물학회지
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• 제53권3호
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• pp.180-192
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• 2017

본 연구에서는 깍두기로부터 분리한 유산균으로 발효시킨 사워도우의 항산화 및 항균 활성을 조사하였다. 염기서열 분석을 통해 분리 균주는 99%의 상동성을 가진 Leuconostoc dextranicum SRK03, Lactobacillus brevis SRK15, Pediococcus halophilus SRK22, Lactobacillus acidophilus SRK30, Lactobacillus plantarum SRK38, Leuconostoc citreum SRK 42 및 Lactobacillus delbrueckii SRK60으로 동정되었다. L. dextranicum SRK03, L. acidophilus SRK30, L. plantarum SRK38 혹은 L. delbreckii SRK60과 Saccharomyces cerevisiae KCTC 7246을 혼합하여 $30^{\circ}C$에서 24시간 발효시킨 사워도우의 유산균과 효모수는 각각 $10^9$ 및 $10^7CFU/g$이었으며, 특히 L. dextranicum SRK03으로 제조한 사워도우는 L. acidophilus SRK30, L. plantarum SRK38 및 L. delbreckii SRK60 보다 유의하게 높은 총 산도와 에탄올 및 세포 외 다당류 함량을 나타내었다. L. dextranicum SRK03 및 L. acidophilus SRK30으로 제조한 사워도우는 DPPH 라디칼 소거능과 유지의 과산화 억제능도 높았다. 게다가 L. acidophilus SRK30이 생산한 유기산과 박테리오신에 의해 $25^{\circ}C$에서 5일간 저장하는 동안 사워도우 내 Bacillus cereus ATCC 11778과 Staphylococcus aureus ATCC 6538의 균수는 유의하게 낮은 수준을 유지되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권2호
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• pp.285-294
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• 2011

The abatement of methane emission from ruminants is an important global issue due to its contribution to greenhouse gas with carbon dioxide. Methane is generated in the rumen by methanogens (archaea) that utilize metabolic hydrogen ($H_2$) to reduce carbon dioxide, and is a significant electron sink in the rumen ecosystem. Therefore, the competition for hydrogen used for methanogenesis with alternative reductions of rumen microbes should be an effective option to reduce rumen methanogenesis. Some methanogens parasitically survive on the surface of ciliate protozoa, so that defaunation or decrease in protozoa number might contribute to abate methanogenesis. The most important issue for mitigation of rumen methanogenesis with manipulators is to secure safety for animals and their products and the environment. In this respect, prophylactic effects of probiotics, prebiotics and miscellaneous compounds to mitigate rumen methanogenesis have been developed instead of antibiotics, ionophores such as monensin, and lasalocid in Japan. Nitrate suppresses rumen methanogenesis by its reducing reaction in the rumen. However, excess intake of nitrate causes intoxication due to nitrite accumulation, which induces methemoglobinemia. The nitrite accumulation is attributed to a relatively higher rate of nitrate reduction to nitrite than nitrite to ammonia via nitroxyl and hydroxylamine. The in vitro and in vivo trials have been conducted to clarify the prophylactic effects of L-cysteine, some strains of lactic acid bacteria and yeast and/or ${\beta}$1-4 galactooligosaccharide on nitrate-nitrite intoxication and methanogenesis. The administration of nitrate with ${\beta}$1-4 galacto-oligosaccharide, Candida kefyr, and Lactococcus lactis subsp. lactis were suggested to possibly control rumen methanogenesis and prevent nitrite formation in the rumen. For prebiotics, nisin which is a bacteriocin produced by Lactococcus lactis subsp. lactis has been demonstrated to abate rumen methanogenesis in the same manner as monensin. A protein resistant anti-microbe (PRA) has been isolated from Lactobacillus plantarum as a manipulator to mitigate rumen methanogenesis. Recently, hydrogen peroxide was identified as a part of the manipulating effect of PRA on rumen methanogenesis. The suppressing effects of secondary metabolites from plants such as saponin and tannin on rumen methanogenesis have been examined. Especially, yucca schidigera extract, sarsaponin (steroidal glycosides), can suppress rumen methanogenesis thereby improving protein utilization efficiency. The cashew nutshell liquid (CNSL), or cashew shell oil, which is a natural resin found in the honeycomb structure of the cashew nutshell has been found to mitigate rumen methanogenesis. In an attempt to seek manipulators in the section on methane belching from ruminants, the arrangement of an inventory of mitigation technologies available for the Clean Development Mechanism (CDM) and Joint Implementation (JI) in the Kyoto mechanism has been advancing to target ruminant livestock in Asian and Pacific regions.

• Asian-Australasian Journal of Animal Sciences
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• 제18권8호
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• pp.1199-1208
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• 2005

Abatement of greenhouse gas emitted from ruminants and promotion of biogas energy from animal effluent were comprehensively examined in each anaerobic fermentation reactor and animal experiments. Moreover, the energy conversion efficiency of biomass energy to power generation were evaluated with a gas engine generator or proton exchange membrane fuel cell (PEMFC). To mitigate safely rumen methanogenesis with nutritional manipulation the suppressing effects of some strains of lactic acid bacteria and yeast, bacteriocin, $\beta$1-4 galactooligosaccharide, plant extracts (Yucca schidigera and Quillaja saponarea), L-cysteine and/or nitrate on rumen methane emission were compared with antibiotics. For in vitro trials, cumulative methane production was evaluated using the continuous fermented gas qualification system inoculated with the strained rumen fluid from rumen fistulated Holstein cows. For in vivo, four sequential ventilated head cages equipped with a fully automated gas analyzing system were used to examine the manipulating effects of $\beta$1-4 galactooligosaccharide, lactic acid bacteria (Leuconostoc mesenteroides subsp. mesenteroides), yeast (Trichosporon serticeum), nisin and Yucca schidigera and/or nitrate on rumen methanogenesis. Furthermore, biogas energy recycled from animal effluent was evaluated with anaerobic bioreactors. Utilization of recycled energy as fuel for a co-generator and fuel cell was tested in the thermophilic biogas plant system. From the results of in vitro and in vivo trials, nitrate was shown to be a strong methane suppressor, although nitrate per se is hazardous. L-cysteine could remove this risk. $\beta$1-4 galactooligosaccharide, Candida kefyr, nisin, Yucca schidigera and Quillaja saponarea are thought to possibly control methanogenesis in the rumen. It is possible to simulate the available energy recycled through animal effluent from feed energy resources by making total energy balance sheets of the process from feed energy to recycled energy.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.149-153
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• 2001

To investigate the mode of bactericidal action for antimicrobial peptide, pediocin, synthetic and mutant pediocins were prepared by direct chemical synthesis. Native pediocin was purified from Pedio-coccus acidilactici M and its conformational structure and bactericidal functions were analyzed and compared to synthetic pediocin. Schematic mode of pediocin actions, how pediocin binds on the target cell membrane, penetrates and makes tunnel are proposed. For these purposes, primary and secondary structures of pediocin was analyzed and disulfide bond assignment was also done. The pediocin purified from P. acidilactici M had high effective bactericidal ability against gram positive bacteria, especially Listeria monocytogenes and was very stable at extreme pHs and even at high temperatures such as autoclaving temperature (121$^{\circ}C$). Pediocin was consisted of 44 amino acids with four cysteines. Novel synthetic peptides were achieved by solid phase peptide synthesis(SPPS) method. To explain the function of cysteine in C-terminal region, mutant pediocin, Ped[C24A＋C44A], was synthesized and their structural and biological functions were analyzed. Second mutant pediocin, Ped[KllE], was prepared to explain the function of lysine at 11 of N-terminal part of pediocin, especially loop of $\beta$-sheet, and to predict the initial binding site of pediocin. The native and synthetic pediocins was showed random coil conformation by spectropolarimetry in moderate conditions. This conformation was observed in extreme conditions such as high temperature and low and high pHs, also. Circular dichroism(CD) data also showed the existence of $\beta$-turn structure in N-terminal part both native and synthetic pediocins. A structural model for pediocin predicts that 18 amino acids in the N-terminal part of the peptide assume a three-strand $\beta$-sheet conformation. This random coil in C-terminal part of pediocin was converted to folding structure, helix structure, in nonpolar solvents such as alcohol and TFE. The disulfide bond between $^{9}$ Cys and $^{14}$ Cys was concrete and inevitable, however, evidences of disulfide bond between $^{24}$ Cys and $^{44}$ Cys was not. Data of Ped[C24A＋C44A], pediocin mutant showed that $^{44}$ Cys was required during killing the target cells but not inevitable, since Ped[C24A＋C44A] still have bactericidal activity but much less than native pediocin. Another pediocin mutant, Ped[KllE], had still bactericidal activity, was controversial to propose that positive charge like as $^{11}$ Lys in loop or hinge in bacteriocin bound or helped to binding to microorganism with electrostatic interaction between cell membrane especially teichoic acid and positive amino acid nonspecifically. The conformation of pediocin among native, synthetic and mutant pediocins did not show big difference. The conformations between oxidized and reduced pediocin were almost similar regardless of native or synthetic.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.225-236
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• 2013

Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at $30^{\circ}C$. Interestingly, antibacterial activity remained unchanged after heating at $121^{\circ}C$ for 45 min, 24 h storage in temperature range of $70^{\circ}C$ to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium.

• 한국식품과학회지
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• 제34권3호
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• pp.536-539
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• 2002

본 연구에서는 증자 콩에 증식하여 부패취를 유발하는 오염균인 야생고초균의 생육을 억제하고 정상발효를 유도하기위해 젖산, 과산화수소 등과 항균성 물질인 bacteriocin을 생성하는 유산균으로 1단 발효를 실시한 후 장류용 황국균을 접종하여 2단 발효 후 다시 고초균으로 3단 발효시켜 황국균과 고초균의 protease, peptidase를 효과적으로 사용함으로서 단백질 분해율이 높아 아미노산 생성량이 많은 기호성 높은 고품질의 메주를 제조하였다. 3단 발효법으로 제조된 메주의 수분함량과 pH를 측정한 결과 각각 54.0 %와 pH 7.0였고 제조된 메주를 30일간 20% 염수로 용출하여 총 유리 아미노산함량을 비교한 결과 3단 발효법으로 제조된 메주구가 대조구에 비해 약 $3{\sim}5$배 높게 나타났다. 특히 장류의 맛을 좌우하는 감칠 맛 성분인 glutamic acid와 aspartic acid의 함량은 대조구에 비해 매우 높아 메주를 원료로 제조하는 장류의 품질을 향상시킬 수 있으며 유리아미노산이 용출되는 시간이 대조구보다 짧아 장류 제조시 발효기간을 1/3정도로 단축시킬 수 있다.

• 한국식품저장유통학회지
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• 제6권4호
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• pp.514-520
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• 1999

김치의 저장성과 기증성 향상을 위한 기초 연구로 서, 유기게르마늄(Ge-132)과 올리고당(프럭토)을 함유하는 배추김치의 생즙액에 3가지 젖산균으로 조합한 스타트를 첨가하여 3$0^{\circ}C$에서 발효시키면서, pH, 산도, $CO_2$생성량, 환원당 및 젖산균수의 변화를 조사하였다. 게르마늄 첨가구는 박테리오신을 생산하는 SNF-13 분리 젖산균주와 E. faecium의 혼합배양(I)에서 유기산과 $CO_2$생성량이 가장 적었으며, 스타트유래의 짖산균수 증식을 촉진시켰고, 환원당 소비량은 가장 많았다. 올리고당 첨가구는 4가지의 혼합배양에서 모두 각각의 대조구 및 게르마늄 첨가구보다 훨씬 유기산 및 $CO_2$생성량이 많았으며, 김치유래의 젖산균수 증식을 촉진시켰다. 유기게르마늄은 박테리오신을 생산하거나 게르마늄 저농도에서 생육이 촉진되는 내산성의 유산균과 혼합병용하면, 김치의 기능성 증진(저장성, 생리활성)의 미네랄로서 활용가능성이 높을 것으로 판단된다.

• Weed & Turfgrass Science
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• 제2권1호
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• pp.38-46
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• 2013

토양 방선균 유래의 천연 제초활성 후보소재를 발굴하고, 이 후보소재의 온실 및 포장 실증 평가를 통해 보다 친환경적이고 효율적인 잡초 관리를 위한 잡초방제제로의 실용화 가능성을 검토하고자 본 연구를 수행하였다. 3,000여 종의 토양 방선균으로부터 강력하고 독특한 제초활성을 발현하는 후보 방선균 2종을 선발하였으며, 선발된 후보 방선균의 16S rDNA 서열을 분석한 결과 S. scopuliridis RB72와 가장 유사도가 높아 선발 균주를 S. scopuliridis KR-001이라 명명하였다. 후보 방선균의 최적 배양조건을 확립하였고, 온실 및 포장조건에서 주요 문제잡초와 난방제 잡초, 환경 위해 잡초 가시박 방제효과를 평가를 통해 친환경적인 천연물 제초제로서의 개발 가능성을 확인하였다. 한편, 후보 방선균 S. scopuliridis KR-001 배양액은 작물에 대한 선택성은 없었기 때문에 비선택성 경엽처리제로의 개발 가능성을 고려한 처리 농도 및 시기 등에 대한 진전단계 연구를 진행할 필요성이 제기되었다. 향후 배양액 수준에서 제형 연구를 통해 약효증진기술과 대량생산성 기술 개발을 통해 실용화 가능성을 검토하는 한편, 배양액 내의 살초성분에 대한 화학구조 구명을 통해 방선균 유래의 천연 제초제를 개발 할 수 있는 선도물질 발굴을 위한 추가 연구가 필요한 것으로 판단하였다.