• YAKHAK HOEJI
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• v.21 no.1
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• pp.1-16
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• 1977

The effect of condensates of phosphates on the preservative activity of the food additives, using eight micro-organisms, has been studied by the agar dilution method. It was found that condensates of phosphates increased the food preserving action of almost all of preservatives and they acted as a synergist for the action of almost all of preservatives. Disodium dihydrogen prrophosphate acted as the strongest synergist in the experiment. But sodium tripolyphosphate anhydrous, sodium poly-phosphate, sodium tripolyphosphate and sodium hexametaphosphate acted as a inhibitor for action of some preservatives on some orgnisms. The preservatives were sodium dehydroacetate (DHA), potassium sorbate and NaNO$_{2}$ etc. The action of sodium meta-phosphate on the preservatives produced a mean difference by their origins. It was supposed that such a difference was produced by the difference of amount of impurities that were contained in sodium metaphosphate, It was also supposed that the does of the preservatives could be reduced by addition of condensates of phosphates, acting as a synergist for the action of almost all of the preservatives.

• Korean Journal of Veterinary Research
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• v.17 no.1
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• pp.13-16
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• 1977

In order to know the current status of sensitivity of Corynebacterium renale to some antimicrobial agents of current use, the sensitivity of 37 strains isolated from urine and vaginal cavity of healthy Korean native cattle and dairy cattle was studied by agar plate dilution method, and their sensitivity according to serological types was compared. The antimicrobial agents tested were streptomycin (SM), erythromycin (EM), oxytetracycline (OT), penicillin G (PC), gentamycin (GM), kanamycin (KM), ampicillin (AP), leucomycin (LM), chloramphenicol (CM), colistin (CL), sulfadimethoxine (SDM) and sulfadiazine (SDZ). Most strains were highly sensitive to PC, GM, AP, LM and KM, and moderate to CM and OT, but resistant to SM, EM, CL, SDM and SDZ. Serological type II was more sensitive to EM, SDM and SDZ than type I and II, but more resistant to SM.

• Archives of Pharmacal Research
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• v.16 no.2
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• pp.161-163
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• 1993

In order to evaluate the antimicrobial effect of 2,3-disubstituted-1,4-naphthalenedione derivatives, we synthesized several 2-chloro, 2-bromo and 2-hydroxy-3(substituted)-1, 4-naphthalene-diones (1-25). These derivatives were tested for antifugal and antibacterial activities, in vitro, against Candida albicans 10231 and local, Aspergillus niger KCTC 1231, Tricophyton mentagrophytes KCTC 6085, Baciilus subtilis ACTT 6633, Pseudomonas aeruginsa NCTC 10490, Staphylococcus aureus ATCC 6538P, Escherichia coli NIHJ. The MIC values were determined by the two-fold agar dilution/strea method. Among these derivatives, 4, 5 and 6 showed the potent antifungal activities. Also 5 and 6 had the antibacterial activities. 5 with (1,2,4-triazolyl)-amino moirty was the most effective in preventing the growth of fungi, such as Candida albicans, Aspergillus niger and Tricophyton mentagrophytes.

• CELLMED
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• v.2 no.2
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• pp.20.1-20.5
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• 2012

$Gynura$ $segetum$ (Lour.) Merr. ($Compositae$) is a well recognized medicinal plant in Indonesia and Malaysia. It is believed to have an anticoagulant effect and is used in treating snake-bites, inflammations and other skin afflictions. This study was carried out to evaluate the antimicrobial effects of $Gynura$ $segetum$ leaves extracts and its fractions. The chemical compositions of the active extracts were also determined. The antimicrobial activities of different solvent extracts of leaves of $Gynura$ $segetum$ were evaluated using the agar well-diffusion method. The Minimum Inhibitory Concentration (MIC) of the active subfractions was determined by the tube dilution method. Gas Chromatography-mass spectrometry (GC-MS) analysis was carried out to identify the chemical compositions of the active extracts. The ethyl acetate fraction and its subfraction E4 performed potent antimicrobial activities and fifteen known chemical constituents were identified by GCMS analysis as 4-vinylphenol, 1-tetradecene, phenol, 2,4-bis(1,1-dimethylethyl), 1-hexadecene, E-15-heptadecenal, hexadecanoic acid, 1,2-benzenedicarboxylic acid, dibutyl ester, 1-docosene, octadecanoic acid, 1-eicosene, cyclotetracosane, 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl)ester, butanedioic acid, monomethyl ester, niacin and 4-hydroxy-benzoic acid. The results of this study suggested a connection between the antimicrobial activities and the chemical structures. The plant may be used as a potential source for antimicrobial agents.

• Archives of Pharmacal Research
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• v.21 no.1
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• pp.6-11
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• 1998

The activities of two types of antiulcer agents against 9 strains of Helicobacter pylori (H. pylori) were determined by the agar dilution method. The antiulcer agents were YJA20379, a newly synthesized proton pump inhibitor developed by Yung-jin Pharmaceutical company, and omeprazole. Both compounds were found to have significant activities against this organism. The MIC values of YJA20379 and omeprazole were 11.7 and $31.25{\mu.g/ml}$ respectively. In addition, the inhibitory potency of both compounds was investigated on H. pylori urease which is believed to be an important colonization and virulence factor in the pathogenesis of gastritis and peptic ulcers. These compounds dose-dependently inhibited urease extracted with distilled water and their $IC_50$ values were $16.4{\times}10^{-5} M and 14.3{\times}10^{-5}M,$ respectively. In addition, a pH-dependent study to determine whether inhibitory potency would be activated by acid condition was performed. It was found that unlike omeprazole, YJA20379 was not affected by acid condition. To determine the inhibition pattern and optimal concentration of substrate, kinetics were evaluated at various pH levels (pH 5.0, 7.0, and 8.5). The data show that YJA20379 noncompetitively inhibited H. pylori urease and $K_M/K_i$values were 0.96 $mM/60{\mu}M (pH 5.0), 0.56 mM/141.5 {\mu}M (pH 7.0)$, and $1.94mM/34{\mu}M (pH 8.5)$, respectively. Based on data obtained, it is concluded that YJA20379 is a significant inhibitor of H. pylori growth and urease and therefore, taking these results into consideration, YJA20379 might be a beneficial therapy for gastritis and peptic ulcers induced by H. pylori.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.189-199
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• 2000

To search for the antifungal substances, various actino-mycete isolates were obtained from various soils of Korea using plate dilution method on the humic acid vitamin agar plates. In the screening procedures using a dual culture method, 32 actionomycete isolates were selected, which showed the inhibitory activity against mycelial growth of plant pathogenic fungi Altirnaria mali, Colletotrichum gloeosporides, Fusarium oxysporum f.sp. cucumerinum, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. Bioassay of the crude extracts from culture filtrates and mycelial mets revealed that 12 antagonistic actionomycetes produced highly active antifungal substances. Actinomycete strain S5-55 which showed the substantial antifungal activity against the tested fungi was selected for production of the antifungal substances. Based on the cytochemical and morphological characteristics, strain S5-55 was identified as a Streptomyces species. The results of the numerical identification using the TAXON program confirmed that Streptomyces strain S5-55 was identical with Streptomyces humidus including in TAXON major cluster 19. The production of antifungal substance was most favorable when S. humidus strain S5-55 was cultivated for 10 dats on soluble starch broth supplemented with $K_2$HPO$_4$. The antifungal substances active against the plant pathogenic fungi P. capsici and M. grisea were partially purified using $\textrm{C}_{18}$ reversed-phase column chromatography.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.381-385
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• 1986

Twenty strains of penicillin(PC)-resistant Staphylococcus aureus ($MIC{\geqq}32U/ml$) were chosen randomly from recent isolates and submitted to the present experiment to see what effect the combined antibiotic action of moxalactam(MX) and fosfomycin(FM) would bring about on the cells, using MS-2 system. 1. The conventional agar dilution method and the rapid automatic MS-2 system were used in measuring the MICs of MX and FM against each strain and the comparison of the data obtained revealed no significant difference between the two methods in the titer and distribution of the MICs. 2. The automatic MS-2 system was, therefore, used alone in determining the combined growth inhibitory effect of MX and FM because of its more rapidness, and the obtained results were that most of the PC-resistant strains(16 out of 20, 80%) were synergistically inhibited by the two antibiotic combination while additive effect was observed in the remaining 4 strains(20%). 3. Thus, it is suggested that the growth of PC-resistant staphylococcal cells may be synergistically inhibited by MX and FM combination and the efficiency of two antibiotic action as well as MIC of single antibiotic may be more rapidly determined by the MS-2 system than by the conventional method.

• Journal of Korean society of Dental Hygiene
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• v.14 no.1
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• pp.95-100
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• 2014

Objectives : The purpose of the present study was to investigate the effect of bamboo charcoal on Streptococcus mutans which is one of the most important causative agents of dental caries. Methods : S. mutans was incubated with or without bamboo charcoal and then changes were observed in its cell viability and antibacterial effect. Oral epithelial cells viabillity(human gingival fibroblast, HGF) was performed using MTT assay. Antibacterial effect was analyzed using a dilution plating method and agar diffusion method. Results : Oral epithelial cells, human gingival fibroblast (HGF) showed a tendency to increase in bamboo charcoal treatment solution concentrations(0.5, 1, 2, 3, 5, 10%). The bamboo charcoal had an antibacterial effect on S. mutans. Antibacterial effect of bamboo charcoal for the bacterium was 58%. Charcoal concentration of 2% and 5% in the inhibition zone showed a minimal growth, but the concentration of 10% bamboo charcoal in inhibition zone revealed a conspicuous antibacterial activity. Conclusions : Overall results suggested that the bamboo charcoal proved to be bactericidal effect on S. mutans.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.18-27
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• 1997

The isolation, morphological study and growth characteristics of the algae were investigated from Lake Chuam. The isolated algae were applied the Agal Growth Potential test. The method of isolation and purification of the algae were used to Agar plating(AP), nutrient enrichment(NE), dilution(DI) and micro capillary technique(MC). Total isolated algae were 21 species. They were composed of Cyanophyceae, Dinophyceae, Bacillariophyceae, Euglenophyceae and Chlorophyceae. The numbers of algal strain by isolation technique were highest in dilution(21 species), and those of the rests were showed in order of NE > MC > AP. The sizes of isolated Selenastrum and Scenedesmus were $1.8\pm 1.4 \mu m$, $3.3\pm 0.9 \mu m$ in diameter and $6.4\pm 2.3 \mu m$, $13.6\pm 1.9 \mu m$ in length respectively. The morphology of isolated algae and NIES-collection strain was very similar each other, but the size was smaller isolated algae than that of NIES-collection. The optimum culture condition of isolated Selenastrum and Scenedesmus was about 30$\circ$C(25$\circ$C-35$\circ$C) in temperature and the maximum growth was appeared between 7,000 lux and 8,000 lux in the light intensity. The comparison of $\mu$(specific growth rate) on the concentration of nutrients such as nitrate and phosphate, isolated Selenastrum was appeared maximum it at 1.0 mg $NO_3-N/l$ but NIES-collection strain was showed 95% of maximum it at same nitrate concentration. Maximum g of isolated algae and NIES-collection strain in Scenedesmus onto nitrate concentration were very similar with the result of selenastrum. The specific growth rates of isolated algae and NIES-collection strain on the gradient concentration of phosphate were showed 0.72/day and 0.70/day at 0.02 mg $PO_4-P/l$ in Selenastrum but those of Scenedesmus were appeared 0.61/day and 0.57/day at same concentration $PO_4-P$.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.165-170
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• 2006

The antifungal activity of crude methanolic extract and fractions from Yucca smalliana Fern. leaves, roots and flowers were investigated in vitro against a panel of plant pathogenic fungi. The minimal inhibitory concentration(MIC) was determined by an agar dilution method. Preliminary liquid culture and agar plate assays showed that the growth of Fu sarium oxysporum, Phytophthora capsici, Rhizoctonia solani and Botrytis cinerea were inhibited by Y. smalliana extracts. The extracts from flowers and leaves showed antifungal activity of 64.0% and 34.0% against F. oxysporum, 66.0% and 62.0% against P. capsici, and 27.0% and 41.0% against B. cinerea, respectively. The methanolic extract from Y. smallina leaves in distilled water was fractionated using solvents of increasing polarity: hexane, ethyl acetate and butanol. These fractions had a broad spectrum of antifungal activity, found to reside entirely in the butanol and aqueous fraction. The aqueous fraction showed inhibition rate of 60.0, 67.8, 84.6 and 58.3% against F. oxysporum, R. solani, C. gloeosporioides, and B. cinerea, respectively, and the butganol fracgtion showed 36.0, 46.0, 66.1 and 58.3%, respectively. Phenolics(e.g. flavonoids, steroids and terpenoids) were observed in the thin layer profile of the different fractions. Leave extract showed a prominent antioxidant activity totally scavenging the free radical of DPPH at a concentration of 1 mg/ml.