• 대한소아치과학회지
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• 제24권2호
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• pp.449-459
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• 1997

Streptomyces exfoliatus의 mutan 분해 능력에 영향을 미치는 인자에 대해 알아 보고자 blue mutan 을 이용한 실험을 실시하여 다음과 같은 결과를 얻었다. Blue mutan이 들어 있는 배지에서 Streptomyces exfoliatus에 의한 투명대를 봄으로써 mutanase 의 분비를 확인할 수 있었다. Blue mutan이 들어 있는 여러 종류의 배지 중에서 minimal essential agar 상에서 Streptomyces exfoliatus가 투명대를 형성하였다. Minimal essential broth의 pH가 7.0일 때 pH가 5.5나 8.5일 때보다 blue mutan이 잘 분해되었으며, 배양 온도가 $37^{\circ}C$ 때 $32^{\circ}C$나 $42^{\circ}C$ 때보다 잘 분해되었다 (P<0.05). Minimal essential broth 에서의 blue mutan의 분해는 $CaCl_2$ 농도가 증가할 수록 (P<0.05), KCl 농도가 10mM일 때 증가하였으나, $MgCl_2$ 농도는 0.1mM에서 6.4mM의 범위에서 비슷하였다. Streptomyces exfoliatus 배양 상청액을 0.5% yeast extract와 10% sucrose를 첨가한 2배의 BHI broth에 가한 경우 교정용 wire상에서의 Streptococcus mutans에 의한 인공치태 형성이 유의성있게 억제되었다(P<0.05). 이상의 결과를 종합하면 Streptomyces exfoliatus에서 생성되는 배양 상청액내의 mutanase 가 인공치태 형성에 억제 작용이 있다는 것을 확인할 수 있었다.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.159-160
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• 2014

An antifungal antibiotic was extracted three times using n-butanol from the culture broth of Bacillus sp. Bioassayguided column chromatography with silica gel and Sephadex LH-20 yielded 62 mg of the original active compound from 1 L of culture broth. The minimal inhibitory concentration values were 25 and $50{\mu}g/ml$ against Pyricularia oryzae and Pellicularia filamentosa, respectively. Based on results obtained from the analysis of the structure of the antibiotic using MS, NMR, and IR spectroscopy, the antifungal antibiotic was shown to consist of only six of fructose.

• 대한소아치과학회지
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• 제25권3호
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• pp.619-626
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• 1998

The critical etiologic factor in the development of dental caries is dental plaque. The main component of dental plaque is the mutan produced by Streptococcus mutans. The following results were obtained by using blue mutan to assess the factors affecting the mutan-digesting activity of Micromonospora aurantiaca isolated from oral cavity. Micromonospora aurantiaca digested more blue mutan in the minimal essential broth at pH 7.0 than at pH 5.5 or 8.5, and at $37^{\circ}C$ than at $32^{\circ}C\;or\;42^{\circ}C$. Blue mutan was similarly digested at the range of 1mM to 16mM of $CaCl_2$ and 0.1mM to 6.4 mM of $MgCl_2$, while being significantly digested at the concentration of 2.5mM of KCl. When the concentration of glucose was decreased in the minimal essential broth, the digestion of blue mutan was increased. When the culture supernatant of Micromonospora aurantiaca in the RL broth with 1% glucose or 0.5% mutan was mixed with 2 ${\times}$ BHIYS broth containing 0.5% yeast extract and 10% sucrose, the formation of artificial plaque on the orthodontic wires by Streptococcus mutans was inhibited(p<0.05). These results indicated that the production of mutanase was identified in the culture supernatant of Micromonospora aurantiaca, suppressing the formation of artificial plaque by Streptococcus mutans.

• 한국미생물·생명공학회지
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• 제23권1호
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• pp.81-86
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• 1995

A Streptomyces strain YS-943, which produced amino acid antimetabolite, was isolated from soil. During the course of screening for new amino acid antimetabolites from the culture broth of Actinomycetes, we found that the strain produced a substance active against Gram-positive bacteria and its activity was reversed by L-methionine and L-histidine on the synthetic minimal agar medium in the culture broth.The morphological and cultural characteristics serve to identify the producing organism strain YS-943 as the genus Streptomyces. Fermentation was carried out in the synthetic medium at 28$\CIRC$C for 48 hours. The fermentation yield reached about 12 mg per liter of the broth. The YS-943 substance was obtained as white powder, mp 194$\CIRC$C and has the molecular formular of C$_{4}$H$_{8}$N$_{2}$O$_{4}$. Its structure was determined to be o-carbamyl-D-serine by spectroscopic data. It is active against some Gram-positive bacteria and reversed by L-methionine and L-histidine.

• 한국미생물·생명공학회지
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• 제46권3호
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• pp.194-200
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• 2018

Glycogen plays important roles in bacteria. Its structure and storage capability have received more attention recently because of the potential correlations with environmental durability and pathogenicity. However, the low level of intracellular glycogen makes extraction and structure characterization difficult, inhibiting functional studies. Bacteria grown in regular media such as lysogeny broth and tryptic soy broth do no accumulate large amounts of glycogen. Comparative analyses of bacterial media reported in literature for glycogen-related studies revealed that there was no consistency in the recipes reported. Escherichia coli $DH5{\alpha}$ is a convenient model organism for gene manipulation studies with respect to glycogen. Additionally, M9 minimal salts medium is widely used to improve glycogen accumulation, although its composition varies. In this study, we optimized the M9 medium by adjusting the concentrations of itrogen source, tryptone, carbon source, and glucose, in order to achieve a balance between the growth rate and glycogen accumulation. Our result showed that $1{\times}M9$ minimal salts medium containing 0.4% tryptone and 0.8% glucose was a well-balanced nutrient source for enhancing the growth and glycogen storage in bacteria. This result will help future investigations related to bacterial physiology in terms of glycogen function.

• 대한의생명과학회지
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• 제22권4호
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• pp.167-173
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• 2016

The broth microdilution technique used to measure the minimal inhibitory concentration (MIC) of natural compounds against bacteria is problematic: it is difficult to visualize bacterial growth due to the color of the natural compound. Therefore, the use of a colorimetric method with a redox indicator by broth microdilution can simplify it and increase its objectivity. This study evaluated the usefulness of the colorimetric method in measuring the MIC of Phellinus baumii against methicillin-resistant Staphylococcus aureus (MRSA). The inhibition in disc diffusion method was observed from $8,192{\mu}g/mL$ P. baumii in all 10 MRSA isolates examined; however, the MIC ranges of the 10 MRSA isolates was $512{\sim}2,048{\mu}g/mL$ by broth microdilution using a colorimetric method; with the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) indicator. In addition, the MIC of P. baumii by broth microdilution using MTT as indicator yielded excellent results. However, the 2, 3, 5-triphenyltetrazolium chloride (TTC) results could not be determined due to the color of the TTC indicator. The MICs of four antibiotics against MRSA using MTT or TTC were equal to those determined by visual interpretation. In conclusion, to evaluate the antibacterial effects of a natural compound, the broth microdilution technique is considered to be better than the disc diffusion method. Moreover, to resolve the problems caused by the colors of natural compounds, a colorimetric method such as that using MTT may be very valuable.

• 약학회지
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• 제40권6호
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• pp.653-658
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• 1996

As part of our search for less toxic antimicrobial agents from natural resources. rutin was isolated from Sophora japonica and then hydrolyzed to quercetin. Antimicrobial activity of quercetin was tested in vitro against five kinds of gram positive and ten kinds of gram negative bacteria by serial broth dilution method. Among fifteen kinds of bacteria tested, the antimicrobial activity of quercetin was the most potent against Proteus vulgaris showing minimal inhibitory concentration(MIC) of 125 ${\mu}$g/ml. To investigate the effect of antimicrobial combinations of quercetin with four kinds of antibiotics (ampicillin, cefazolin, oxytetracycline and chloramphenicol). the fractional inhibitory concentration index (FICI) was determined by checkerboard assay for each strain. The antimicrobial combinations of quercetin with four kinds of antibiotics resulted in synergism in one instance, additive effect in four instances, but no antagonism was observed.

• KSBB Journal
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• 제6권1호
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• pp.69-77
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• 1991

When S. fradiae was cultured in S medium, it stavted to produce neomycin in the middle of stationary phase of growth. Antibitoic production is regulated not only by glucose but also by metabolites formed from glucose. A chemically defined minimal salt broth was developen for the study of metabolites activating produition of antibiotic in a neomycin producer. When growth and production or antibiotic in minimal salt broth was examined with a full grown or a vefctativc mycelium, the medium was found not to be good for the growth, but to be good enough for the production of antibiotic with a full grown mycelium. When many carbotlydrates, organic acids, or alcohol were supplmented with instead of glucose in the medium suspcndcn with a full grown mycelium, the amount of antibiotic produced in the medium containing fumaratc was 5 times more than that in the medium with glucose. Further study indicated that the medium is not good also for the growth but good for the production of antibiotic. The antibiotic produced in this medium was identified to be neomycin. The activation of the production of neomycin by fumarate was further confirmed in a complex medium. Fuinarate is suspected to initiate and to activate the biosynthesis of neomycin at the gene level.

• 한국식품위생안전성학회지
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• 제15권1호
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• pp.55-59
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• 2000

Bamboo oil의 천연 보존료로서의 가치를 평가하기 위해 합성 보존료인 BHA와 이미 수입되어 사용되고 있는 천연보존료인 tea tree oil을 비교하기 위하여 disc diffusion법과 broth dilution 법으로 S. aureus와 E. coli대한 항균력을 검토한 결과를 요약하면 다음과 같다. 1. Disc diffusion법으로 S. aureus에 대한 항균력을 조사한 결과 BHA>tea tree oil>bamboo oil 순이었고 E. coli에 대한 항균력은 bamboo oil이 가장 강하게 나타났으며 다음은 BHA>tea tree oil순으로 나타났다. 2. Broth dilution법으로 S. aureus와 E. coli모든 시료 6.0$\mu$l/ ml 이상에서 모두 측정되지 않아 모든 시료에서 동일하게 최소억제농도가 6.0$\mu$l/ ml 이상 필요한 것으로 나타났다. 3. Bamboo oil의 이용 개발 시 경제적 조건은 동일한 항균력을 기대할 때 tea tree oil에 비하여 약 20%정도 저렴하여 경제성이 충분히 있는 것으로 나타났다.

• 한국동물위생학회지
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• 제23권1호
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• pp.19-28
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• 2000

There are several main antibacterial susceptibility tests, such as agar dilution method, broth dilution method and disk diffusion technique. Especially, for minimal inhibitory concentration (MIC) test, agar dilution method has been widely used. But that method is so complicated and bothering that it's difficult to treat a large amount of strains. On the other hand, modified broth dilution method(add 1% glucose and 0.018% phenol red as a pH indicator to broth) is fast and easy to perform. Most of all, it can visualize the result by color. The MICs of 22 antibiotics Including penicillins, aminoglycosides, cephalothin, chloramphenicol, lincomycin, ceftiofur, vancomycin and quinolones, erythromycin, colistin. sul-fadimethoxine, trimethoprim for arcanobacterium pyogenes 14 strains, actinobacillus pleuropneu-moniae 41 strains and pasteurella multocida 37 strains, which were collected from porcine during 1996 ∼ 1999, were determined by modified broth dilution method. Actinobacillus pleuropneumoniae was highly susceptible to all kinds of quinolones such as ciprofloxacin, enrofloxacin and norfloxacin and to all aminoglycosides, like gentamicin, apramycin, kanamycin and ampicillin, cephalothin and ceftiofur. But It was quite resistant to solfadimethoxin, colistin and vancomycin. Pasteurella multocida was found to have high susceptibility to ampicillin, cephalothin, chlorampenicol and gentamicin but had mid-degree susceptibility to other aminoglycosides. In addition, it was susceptible to norfloxacin and nalidixic acid, but not to newer fluoroquinolone like ciprofloxacin and enrofloxacin and it was resistant to colistin and kanamycin. Arcanobacterium pyogenes was highly susceptible to most of quinolones such as cipoofloxacin, enrofloxacin and norfloxacin and gentamicin and penicillin G. But it also obtained high resistance against the early quinolone, nalidixic acid and aminoglycosides such as amikacin, apramycin and kanamycin and erythromycin, chlorampenicol, tetracyclin and vancomycin.