• 구강회복응용과학지
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• 제37권4호
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• pp.244-250
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• 2021

목적: 본 연구의 목적은 Streptococcus salivarius K12의 성장과 항균활성에 대한 배양조건의 영향을 알아보는 것이다. 연구 재료 및 방법: S. salivarius K12는 동물 또는 식물 단백질을 함유한 배지 또는 중성 및 산성 조건의 배지에서 배양되었다. S. salivarius K12의 성장은 2시간마다 분광광도계로 측정하였다. S. salivarius K12의 Streptococcus mutans, Porphyromonas gingivalis 및 Candida albicans에 대한 항균 또는 항진균 활성을 배양액을 이용한 감수성 분석으로 조사하였다. 결과: S. salivarius K12의 성장은 식물 단백질과 중성 pH 조건에서 더 빠른 성장을 보였다. S. salivarius K12의 항균 및 항진균 활성은 동물성 단백질보다 식물성 단백질을 함유한 배지에서 더 강하게 나타났다. 결론: S. salivarius K12를 세균성 구강질환에 적용하기 위해서는 S. salivarius K12가 구강 내에서 군집화하여 항균 활성을 향상시키기 위한 보조물질이 필요할 수 있다.

• 미생물학회지
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• 제51권3호
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• pp.271-279
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• 2015

락토페린(LF)는 철이온과 결합하는 당 단백질로서 항균, 항바이러스, 항진균 등의 기능을 가지고 있으며, 생체의 각종 체액으로부터 분비되는 다기능성 단백질이다. 본 연구에서는 사람의 락토페린(hLF)으로부터 유래된 N-lobe의 유전자를 분리하고 산업용 균주로서 많이 사용되는 메탄올자화 효모인 Pichia pastoris에서 발현시켰다. 재조합 사람 락토페린 N-lobe (rhLF-N)는 배양액으로 분비 발현되었으며, 3L 발효조에서 약 $458{\mu}g/ml$이 수준으로 생성되었다. rhLF-N을 정제한 다음 SDS-PAGE와 western blot으로 분석하여 분자량 35 kDa 단백질을 확인하였으며, hLF에 대한 항체를 이용하여 면역확산법으로 면역성을 확인하였다. rhLF-N의 mRNA 발현양상을 qRT-PCR로 분석한 결과 메탄올 첨가에 의한 발현 유도 후 2-3일째에 발현율이 가장 높았으며, 4일째에는 점차적으로 감소하였다. 정제한 rhLF-N을 이용하여 항균활성을 조사한 결과 Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Burkholderia cepacia, Salmonella typhimurium과 같은 병원성 균에 대해 광범위한 항균활성을 보였으나, LF유래 항균 peptide들과 항균활성을 비교하였을 때, 항균력이 상대적으로 매우 떨어지는 것으로 나타났다. 비록 본 연구에서 발현한 rhLF-N은 항균력은 떨어지나, hLF에 비해 그 크기가 작고 배양조건 연구로 P. pastoris에서 대량 생산이 가능하며, 배양액으로 분비시킬 수 있기 때문에 정제 비용 등을 고려 할 때 산업적 응용에는 보다 유리할 것으로 사료된다.

• The Plant Pathology Journal
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• 제25권4호
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• pp.333-343
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• 2009

Here, we show that an endophytic bacterial strain, Enterobacter asburiae B1 exhibits the ability to elicit ISR in cucumber, tobacco and Arabidopsis thaliana. This indicates that strain B1 has a widespread ability to elicit ISR on various host plants. In this study, E. asburiae strain B1 did not show antifungal activity against tested major fungal pathogens, Colletotrichum orbiculare, Botrytis cinerea, Phytophthora capsici, Rhizoctonia solani, and Fusarium oxysporum. Moreover, the siderophore production by E. asburiae strain B1 was observed under in vitro condition. In greenhouse experiments, the root treatment of strain B1 significantly reduced disease severity of cucumber anthracnose caused by fungal pathogen C. orbiculare compared to nontreated control plants. By root treatment of strain B1 more than 50% disease control against anthracnose on cucumber was observed in all greenhouse experiments. Simultaneously, under the greenhouse condition, the soil drench of strain B1 and a chemical inducer benzothiadiazole (BTH) to tobacco plants induced GUS activity which is linked with activation of PR promoter gene. Furthermore, in Arabidopsis thaliana plants the soil drench of strain B1 induced the defense gene expression of PR1 and PDF1.2 related to salicylic acid and jasmonic acid/ethylene signaling pathways, respectively. In this study, for the main focus on root colonization by strain B1 associated with defense responses, bacterial cells of strain B1 was tagged with the gfp gene encoding the green fluorescent protein in order to determine the colonization pattern of strain B1 in cucumber. The gfp-tagged B1 cells were found on root surface and internal colonization in root, stem, and leaf. In addition to this, the scanning electron microscopy observation showed that E. asburiae strain B1 was able to colonized cucumber root surface.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.241-247
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• 2016

Natamycin is a widely used antifungal antibiotic. For natamycin biosynthesis, the gene pimE encodes cholesterol oxidase, which acts as a signalling protein. To confirm the positive effect of the gene pimE on natamycin biosynthesis, an additional copy of the gene pimE was inserted into the genome of Streptomyces gilvosporeus 712 under the control of the ermE* promoter (p_ermE*) using intergeneric conjugation. Overexpression of the target protein engendered 72% and 81% increases in the natamycin production and cell productivity, respectively, compared with the control strain. Further improvement in the antibiotic production was achieved in a 1 L fermenter to 7.0 g/l, which was a 153% improvement after 120 h cultivation. Exconjugants highly expressing pimE and pimM were constructed to investigate the effects of both genes on the increase of natamycin production. However, the co-effect of pimE and pimM did not enhance the antibiotic production obviously, compared with the exconjugants highly expressing pimE only. These results suggest not only a new application of cholesterol oxidase but also a useful strategy to genetically engineer natamycin production.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.351-357
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• 2009

Natural wild-type strains of Bacillus subtilis are extensively used in agriculture as biocontrol agents for plants. This study examined two antagonist B. subtilis strains, KB-1111 and KB-1122, and the results illustrated that KB-1122 was a more potent inhibitor of the indicator pathogen than KB-1111. Thus, to investigate the intrinsic differences between the two antagonist strains under normal culture conditions, samples of KB-1111 and KB-1122 were analyzed using MALDI-TOF-MS. The main differences were related to 20 abundant intracellular and 17 extracellular proteins. When searching the NCBI database, a number of the differentially expressed proteins were identified, including 11 cellular proteins and 10 secretory proteins. Among these proteins, class III stress-response-related ATPase, aconitate hydratase, alpha-amylase precursor, and a secretory protein, endo-l, 4-beta-glucanase, were differentially expressed by the two strains. These results are useful to comprehend the intrinsic differences between the antagonism of KB-1111 and KB-1122.

• 생명과학회지
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• 제16권3호
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• pp.387-395
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• 2006

유도된 집파리유통 hemolymph중에서 Candida albicans의 3가지 anti-fungal peptides를 분리하였다. 3개 anti-fungal peptides는 분자량이 4-16 kDa 사이의 분명한 구별이 있을 뿐만 아니라, 각 peptide는 anti-fungal peptides작용이 있었다. 이들 peptide의 공통 특징은 모두 열을 받은 뒤 활성이 변하지 않는 비교적 강한 내열성을 보여주었다.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.693-699
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• 2010

An antiproliferative ribonuclease with a new N-terminal sequence was purified from fruiting bodies of the edible wild mushroom Russula delica in this study. This novel ribonuclease was unadsorbed on DEAE-cellulose, but absorbed on SP-Sepharose and Q-Sepharose. It had a molecular mass of 14 kDa, as judged by fast protein liquid chromatography on Superdex 75 and SDS-polyacrylamide gel electrophoresis. Its optimal pH and optimal temperature were pH 5 and $60^{\circ}C$, respectively. The ranking of its activity toward various polyhomoribonucleotides was poly C> poly G>poly A>poly U. It could inhibit proliferation of HepG2 and MCF-7 cancer cells with an $IC_50$ value of $8.6\;{\mu}M$ and $7.2\;{\mu}M$, respectively. It was devoid of antifungal and HIV-1 reverse transcriptase inhibitory activity.

• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.784-795
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• 2018

Bacillus amyloliquefaciens Pc3 was isolated from Antarctic seawater with antifungal activity. In order to investigate the metabolic regulation mechanism in the biosynthesis of lipopeptides in B. amyloliquefaciens Pc3, GC/MS-based metabolomics was used when exogenous indole was added. The intracellular metabolite profiles showed decreased asparagine, aspartic acid, glutamine, glutamic acid, threonine, valine, isoleucine, hexadecanoic acid, and octadecanoic acid in the indole-treated groups, which were involved in the biosynthesis of lipopeptides. B. amyloliquefaciens Pc3 exhibited a growth promotion, bacterial total protein increase, and lipopeptide biosynthesis inhibition upon the addition of indole. Besides this, real-time PCR analysis further revealed that the transcription of lipopeptide biosynthesis genes ituD, fenA, and srfA-A were downregulated by indole with 22.4-, 21.98-, and 26.0-fold, respectively. It therefore was speculated that as the metabolic flux of most of the amino acids and fatty acids were transferred to the synthesis of proteins and biomass, lipopeptide biosynthesis was weakened owing to the lack of precursor amino acids and fatty acids.

• 한국식품영양학회지
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• 제20권4호
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• pp.369-377
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• 2007

An investigation evaluating the preparation and physicochemical properties of sauce with various herbs(sancho, sage, and rosemary) derived from soy sauce was performed. The effects of the different kinds of herbs added to sauce for roasted mackerel were assessed using physiochemical, sensory, flavor, and texture analysis properties. This fish was then compared to, fish with salt. The moisture, crude protein, crude fat, and crude ash content of the roasted mackerel were significantly higher than the control(p<0.05, p<0.001). The salinity content of the herb sauce added samples were significantly higher than the control(p<0.05). Conversely, the pH and peroxide value of the herb sauce added samples were significantly lower than the control(p<0.001). A positive trend was observed for color value with sancho added sauce(p<0.001). The another positive effects on the texture of fish was observed for texture analysis, adhesiveness, springiness, gumminess, and chewiness with herb sauce added samples(p<0.05). In the flavor profile, the fishy smell was disappeared and antifungal flavor was improved with herb added sauce. Flavor, taste, texture, and overall preference of herb sauce were significantly highest in sancho added sauce(p<0.05, p<0.001). Results suggest that the best herb sauce for roasted mackerel was sancho added sauce.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.121-127
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• 2004

Amphotericin B (AmB), an amphipathic polyene macrolide, is an antifungal drug produced by Streptomyces nodosus. Recently, AmB has been shown to exert antiviral activity against rubella virus and human immunodeficiency virus by different mechanisms. In this study, we evaluated the antiviral effect of AmB against Japanese encephalitis virus (JEV) and investigated which step of the viral life cycle was inhibited by AmB to understand the mechanism of antiviral action of AmB. AmB reduced both plaque size and number in the infected cells in a dose-dependent manner. In addition, a 200-fold reduction of infectious virus titer was observed by treatment of infected cells with $5\mug/ml$ of AmB. AmB acted at the post virus-infection step, but not during adsorption of virus to host cells. Western blot analysis revealed that the accumulated level of JEV envelope protein dramatically decreased in the infected cells by treatment with $5-10\mug/ml$ of AmB. Our results indicate that AmB inhibits the replication of JEV at the postinfection step by interfering with viral replication and/or by inhibiting the synthesis of viral proteins.