• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.338-342
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• 2008

This study was performed to screen and select Lactobacillus strains from chicken feces for probiotic use in animals. Of these strains, strain AU had the highest immunostimulatory effect. Therefore, strain A12 was characterized as a potential probiotic. Strain A12 was tentatively identified as Lactobacillus acidophilus A12, using the API 50 CHL kit based on a 99.9% homology. L. acidophilus A12 was highly resistant to artificial gastric juice (pH 2.5) and bile acid (oxgall). Based on results from the API ZYM kit, leucine arylamidase, crystine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, ${\alpha}$-galactosidase, ${\beta}$-galactosidase, ${\alpha}$-glucosidase, ${\beta}$-glucosidase, and N-acetyl-${\beta}$-glucosamidase were produced by strain A12. L. acidophilus A12 showed resistance to several antibiotics (nisin, gentamicin, and erythromycin). The amount of interleukin $(IL)-1{\alpha}$ in $20{\times}$ concentrated supernatant from L. acidophilus A12 was approximately 156pg/ml. With regard to antioxidant activity, L. acidophilus A12 supernatant showed 60.6% DPPH radical scavenging activity. These results demonstrate the potential use of L. acidophilus A12 as health-promoting probiotics.

• 한국식품영양과학회지
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• 제41권8호
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• pp.1066-1071
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• 2012

본 연구에서는 3가지 서로 다른 미생물을 이용하여 콩을 발효시킨 후 제품의 알레르기성 변화를 살펴보았다. 증자 후 가열 살균된 콩은 유산균(Lactococcus actis subsp. lactis) 그리고/또는 황국균(Aspergillus oryzae) 그리고/또는 고초균(Bacillus subtilis)을 이용하여 발효되었다. 콩 단백질이 발효과정에서 분해됨을 확인하였다. 발효과정 후 콩 단백질의 알레르기성과 항원성의 변화는 콩 단백 특이 다클론 항체 또는 콩에 대해 알레르기 반응을 일으키는 환자들의 혈청을 이용하여 면역반응검사법으로 확인되었다. 콩 단백질은 니아신 생성균주 L. lactis subsp. lactis IFO12007와 황국균 그리고 고초균을 이용한 3단 발효에 의해 가장 강력한 분해가 이루어졌다. 3단 발효 후 콩의 알레르기성 및 항원성도 크게 감소되었다. 본 연구에서 확인된 3단 발효법은 콩의 알레르기성을 저하시키는 강력한 방법 중의 하나이다.

• 한국식품과학회지
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• 제27권2호
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• pp.257-263
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• 1995

As a primary step to develop natural preservative for extending the shelf-life of kimchi, the effect of 102 edible plants, 21 antimicrobial agents and related compounds on kimchi fermentation was studied. Among 42 oriental medicinal plants tested, Baical skullcap and Assam indigo were found to be highly effective for maintaining the fresh state of kimchi. Although Bugbane, Red mangolia, Bushy sophora, Szechuan pepper, Chinese quince and Scisandre significantly inhibit the growth of Lactobacilli, their effect was not high enough to be used as raw materials for kimchi preservative. When the effect of 32 herbs and spices was tested, peppermint, cinnamon, lemon balm, clove, hop, rosemary, sage, horseradish and thyme showed high antimicrobial activity against kimchi microorganisms. Among them, the effect of clove ranked top. When it was added to fresh kimchi, initial cfu value ($2.4{\times}10^{6}cfu/g$) changed little even after 2 day's fermentation ($2.6{\times}10^{6}cfu/g$). Sensory test was not a good criteria to evaluate the effect of herbs and spices, since their highly specific flavors affected the taste of kimchies. Twenty eight fruits, vegetables and related plants were tested, but only leaves of pine tree, persimmon and oak leaves showed a significant bactericidal effect, finally contributing to the storage of kimchi. In addition, when 21 natural preservatives and other compounds were added individually to fresh kimchi, nisin and caffeic acid could inhibit fermentation.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.575-584
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• 2012

Listeria monocytogenes is an important foodborne pathogen that comprises four genetic lineages: I, II, III, and IV. Of these, lineage II is frequently recovered from foods and environments and responsible for the increasing incidence of human listeriosis. In this study, the phylogenetic structure of lineage II was determined through sequencing analysis of the ascB-dapE internalin cluster. Fifteen sequence types proposed by multilocus sequence typing based on nine housekeeping genes were grouped into three distinct sublineages, IIA, IIB, and IIC. Organization of the ascB-dapE internalin cluster could serve as a molecular marker for these sublineages, with inlGHE, inlGC2DE, and inlC2DE for IIA, IIB, and IIC, respectively. These sublineages displayed specific genetic and phenotypic characteristics. IIA and IIC showed a higher frequency of recombination (${\rho}/{\theta}$). However, recombination events had greater effect (r/m) on IIB, leading to its high nucleotide diversity. Moreover, IIA and IIB harbored a wider range of internalin and stress-response genes, and possessed higher nisin tolerance, whereas IIC contained the largest portion of low-virulent strains owing to premature stop codons in inlA. The results of this study indicate that IIA, IIB, and IIC might occupy different ecological niches, and IIB might have a better adaptation to a broad range of environmental niches.

• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1293-1298
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• 2018

Phosphomannomutase (ManB) converts mannose-6-phosphate (M-6-P) to mannose-1-phosphate (M-1-P), which is a key metabolic precursor for the production of GDP-D-mannose used for production of glycoconjugates and post-translational modification of proteins. The aim of this study was to express the manB gene from Escherichia coli in Lactococcus lactis subsp. cremoris NZ9000 and to characterize the encoded enzyme. The manB gene from E. coli K12, of 1,371 bp and encoding 457 amino acids (52 kDa), was cloned and overexpressed in L. lactis NZ9000 using the nisin-controlled expression system. The enzyme was purified by Ni-NTA column chromatography and exhibited a specific activity of 5.34 units/mg, significantly higher than that of other previously reported ManB enzymes. The pH and temperature optima were 8.0 and $50^{\circ}C$, respectively. Interestingly, the ManB used in this study had two substrate specificity for both mannose-1-phosphate and glucose-1-phosphate, and the specific activity for glucose-1-phosphate was 3.76 units/mg showing 70% relative activity to that of mannose-1-phosphate. This is the first study on heterologous expression and characterization of ManB in lactic acid bacteria. The ManB expression system constructed in this study canbe used to synthesize rare sugars or glycoconjugates.

• 한국미생물·생명공학회지
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• 제29권1호
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• pp.50-55
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• 2001

B. subtilis cx1이 생산하는 박테리오신(BSCX1)을 부분 정제하고 특성을 규명하였다. BSCX1은 pH 안정성 실험에서 pH 2.5~9.5 구간에서도 안정되게 항균활성을 유지하였다. 각종 효소에 대한 안정성 실험에서는 protease, trypsin, proteinase K, 그리고 carboxypeptidase로 처리하였을 때는 완전히 항균활성이 사라졌고, $\alpha$-amylase, lipase, aminopeptidase는 항균활성에 영향을 미치지 못하였다. 이상의 결과로 본 항균물질이 단백질계열의 물질이며 당이나 지질 결합은 항균활성에 큰 영향을 미치지 않는 것으로 추정되었다. 그러나 열에는 불안정하여 $60^{\circ}C$이상에서는 15분 안에 완전히 그 항균활성을 상실하였으며 $50^{\circ}C$ 에서는 15분만에 역가의 50%가 실활 되었다. 이에 반하여 저온에서는 무척 안정하여 $-20^{\circ}C$와 $-70^{\circ}C$에서 수개월간 보관하여도 여전히 항균활성을 그대로 유지하였다. Tricin-SDS-PAGE를 통하여 BSCX1의 분자량은 약 9,500 dalton으로 확인되었ekl. BSCX1은 pH2.5에서 9.5에 이르는 넓은 pH 영역에서 그 활성을 유지하므로, 기존에 개발된 nisin이나 유산균 유래의 항균물질이 pH 안정성이 떨어진다는 단점을 보완할 수 있는 생물학적 식품보존제로서의 개발 가능성을 높이 시사하였다.

• 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.

• 산업식품공학
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• 제13권1호
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• pp.64-69
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• 2009

25 종류의 신선 과채류로부터 MRS 한천 고체배지에서 생육하는 1,250주의 유산균을 분리한 후 식중독 세균인 Escherichia coli 0157:H7, Listeria monocytogenes, Bacillus cereus와 유산균인 Lactobacillus plantarum, L. casei, Lactococcus lactis subsp. lactis에 대한 생육저해활성을 조사하였다. 조사한 1,250 균주 중에서 23 종류의 과채류에 존재하는 607 균주(총 조사균주의 49%)가 E. coli 0157:H7, L. monocytogenes 또는 B. cereus에 대한 항균활성을 나타내었다. 이 균주들의 L. plantarum, L. casei, Lactococcus lactis subsp. lactis에 대한 항균활성을 측정한 결과, 7 종류의 과채류에 존재하는 24 균주(총 균주의 3%)가 박테리오신 유사활성을 나타내었으며, 이 균주들의 생리적 형태학적 특징을 조사한 결과 전형적인 유산균의 특징을 지니고 있었다. 24 균주 중에서 3 균주는 nisin을 생산하는 것으로 판단되었으며, RAPD-PCR 분석을 통하여 동일한 과채류에 존재하는 균주들은 유사한 분류학적 특징을 지니고 있는 것으로 확인되었다.