• 한국식생활문화학회지
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• 제16권3호
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• pp.243-249
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• 2001

Antibacterial activities in each part of watercress(Oenanthe javanica D.C.) grown under different culture conditions were measured to determine the possibility to use watercress as a resource to develop the antibacterial substance. The leaves of watercress were extracted with methanol and the methanol extract was further fractionated with various organic solvents. Antibacterial activities against Shigella dysenteriae ATCC 9361 in all fractions were determined according to the agar diffusion method using paper disc. Methanol extract of watercress leaves was more effectively inhibited the growth of the tested bacteria than the extracts of roots or stems at the concentration of 0.5 g eq./disc, and the extract of watercress from Hwasoon was the most effective one as compared to others. Phenolic and neutral fractions fractionated from methanol extract of watercress had a considerable inhibiting activity on the growth of the bacteria, but acidic and basic fractions did not show any inhibitory effect. Minimum inhibitory concentrations of phenolic and neutral fractions against Shigella dysenteriae ATCC 9361 were $400\;{\mu}g/disc$ and $550\;{\mu}g/disc$, respectively.

• Food Science and Biotechnology
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• 제15권5호
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• pp.817-819
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• 2006

8-Quinolinol and other quinolinol derivatives were evaluated with regard to their growth-inhibitory effects against intestinal bacteria, using the paper disk-agar diffusion method. The observed growth responses varied according to the chemicals and dosages used, as well as the bacterial species tested. 8-Quinolinol showed a significant inhibitory effect against Clostridium difficile, C. perfringens, and Escherichia coli, at 5, 2, 1, and 0.5 mg/disk, and also exhibited a very strong inhibitory effect at 0.25 mg/disk. At low concentrations, 8-quinolinol had strong inhibitory effects against C. perfringens at 0.1 and 0.05 mg/disk; 8-quinolinol also manifested a moderate inhibitory effect against C. perfringens at 0.025 mg/disk. Furthermore, 8-quinolinol revealed moderate and weak growth inhibition against C. difficile and E. coli at concentrations of 0.1 and 0.05 mg/disk, respectively, but 2-quinolinol, 4-quinolinol, and 6-quinolinol evidenced no growth inhibition against B. bifidum, B. longum, C. difficile, C. perfringens, E. coli, or L. casei. The inhibitory effects of 8-quinolinol against C. difficile, C. perfringens, and E. coli lead to its consideration as a possible therapeutic modality for the treatment of diseases associated with harmful intestinal bacteria.

• Food Science and Biotechnology
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• 제17권1호
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• pp.191-194
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• 2008

The antagonistic activity of probiotic strains (Bifidobacterium animalis BB-12, Bifidobacterium bifidum A, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus paracasei ATCC 25598, and Lactobacillus rhamnosus GG) against nalidixic acid resistant ($NA^R$) Escherichia coli O157:H7 MF1847, E. coli O157:H7 H2439, E. coli O157:H7 ATCC 43894, and E. coli O157:H7 C7927 was investigated using the agar-overlay, well diffusion, and broth culture tests. L. paracasei ATCC 25598 was the most effective probiotic strain in terms of in vitro antagonistic activity against $NA^R$ E. coli O157:H7, followed by L. rhamnosus GG, B. longum B6, and L. acidophilus ADH. The use of selected probiotic strains could be an effective pre-harvest intervention strategy to reduce the risk of $NA^R$ E. coli O157:H7 by maintaining a balanced microflora in animals and might provide many potential benefits in lieu of using antimicrobials.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.497-502
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• 2008

The essential oil from the cones of Pinus koraiensis was prepared after removing the seeds, and its chemical composition analyzed using gas chromatography-mass spectrometry (GC-MS). Hydrodistillation of the P. koraiensis cones yielded 1.07% (v/w) of essential oil, which was almost three times the amount of essential oil extracted from the needles of the same plant. Moreover, the antimicrobial activities of the oil against the growth of Gram-positive bacteria, Gram-negative bacteria, and fungi were evaluated using the agar disc diffusion method and broth microdilution method. Eighty-seven components, comprising about 96.8% of the total oil, were identified. The most abundant oil components were limonene (27.90%), ${\alpha}$-pinene (23.89%), ${\beta}$-pinene (12.02%), 3-carene(4.95%), ${\beta}$-myrcene (4.53%), isolongifolene (3.35%), (-)-bornyl acetate (2.02%), caryophyllene (1.71%), and camphene (1.54%). The essential oil was confirmed to have significant antimicrobial activities, especially against pathogenic fungal strains such as Candida glabrata YFCC 062 and Cryptococcus neoformans B 42419. Therefore, the present results indicate that the essential oil from the cones of Pinus koraiensis can be used in various ways as a nontoxic and environmentally friendly disinfectant.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.372-377
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• 2009

The chemical compositions and antibacterial and antifungal activities of essential oils extracted from Abies holophylla and A. koreana were investigated. GC-MS analysis revealed that 38 compounds comprised 95.88% of the A. holophylla essential oil, with the main components being bicyclo[2.2.1]heptan-2-ol(28.05%), ${\delta}3$-carene(13.85%), $\alpha$-pinene(11.68%), camphene(10.41%), dl-limonene(7.61%), $\beta$-myrcene(7.11%), trans-caryophyllene(5.36%), and $\alpha$-bisabolol(3.67%). In the essential oil from A. koreana, 36 compounds comprised 98.67% of the oil, and the main compounds were bornyl ester(41.79%), camphene(15.31%), $\alpha$-pinene(11.19%), dl-limonene(8.58%), fenchyl acetate(5.55%), and $\alpha$-terpinene(2.29%). Both essential oils showed great potential of antibacterial activity against several bacteria tested, in the range of 2.2-$8.8{\mu}g$ per disc by the agar disc diffusion method, and minimal inhibitory concentration(MIC) values of 5.5-21.8 mg/ml by the microdilution method. Both oils showed very effective antifungal activities toward all pathogenic strains tested, including Candida glabrata, with MIC values in the range of 0.5-2.2 mg/ml. As a whole, A. koreana oil showed better antibacterial and antifungal properties than A. holophylla oil.

• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.62-70
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• 2011

The antibacterial effects of nine lactic acid bacteria (LAB) against Campylobacter jejuni were investigated by using agar gel diffusion and co-culture assays. Some differences were recorded between the inhibition effects measured with these two methods. Only two LAB, Lb. pentosus CWBI B78 and E. faecium THT, exhibited a clear anti- Campylobacter activity in co-culture assay with dehydrated poultry excreta mixed with ground straw (DPE/GS) as the only growth substrate source. It was observed that the supplementation of such medium with a cellulase A complex (Beldem S.A.) enhanced the antimicrobial effect of both LAB strains. The co-culture medium acidification and the C. jejuni were positively correlated with the cellulase A concentration. The antibacterial effect was characterized by the lactic acid production from the homofermentative E. faecium THT and the lactic and acetic acids production from the heterofermentative Lb. pentosus CWBI B78. The antagonistic properties of LAB strains and enzyme combination could be used in strategies aiming at the reduction of Campylobacter prevalence in the poultry production chain and consequently the risk of human infection.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1550-1554
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• 2003

One hundred of lactic cultures were evaluated for their ability to inhibit hazardous microbes, such as Salmonella enteritidis, Salmonella typhimurium, Escherichia coli, Listeria monocytogenes, and Bacillus cereus by agar well diffusion method. None of them showed inhibitory halo against S. enteritidis, while 27 strains showed inhibitory activity against S. typhimurium, 6 against E. coli, 9 against ampicillin resistant E. coli, 31 against L. monocytogens, 10 against B. cereus. pH of the culture does not explain for the inhibitory activity except against B. cereus. A neutralized culture from corn silage showed highest inhibitory activity against S. typhimurium, and the size of inhibitory halo was same as 10 ug/mL of ampicillin. The culture was identified to be Lactobacillus buchneri on the basis of biochemical characteristics and utilization of substrates. Using the culture as probiotics could be expected to reduce antibiotics for animal feeding.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.217-223
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• 2017

PURPOSE. This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS. Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS. XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION. Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

• Journal of Applied Biological Chemistry
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• 제44권4호
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• pp.185-189
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• 2001

Essential oils of 21 herb plant samples, using spectrophotometric and paper disc agar diffusion methods under anaerobic conditions, were tested in vitro for their growth-inhibiting activities against Bifidobacterium bifidum, B. longum, Lactobacillus casei, Clostridium perfringens, and Escherichia coli. The responses varied with bacterial strains and plant oils. At 10 mg/disk, all essential oils did not inhibit beneficial intestinal bacteria, except for the oil of Alpinia officinarum and Melaleuca alternifolia against L. casei. Due to their strong growth-inhibitory activities against C. perfringens, E. coli, and L. casei, the activites of nine oils were evaluated at low concentrations. In test with C. perfringens at 1 mg/disk, the oils of Amyris balsamifera, Curcuma longa, M. alternifolia, and Trachyspermum ammi showed moderate activities. Moderate activities against E. coli were observed with the oils of M. alternifolia and T. ammi. These results may be indications of at least one of the pharmacological actions of the four herb plants.

• Biomolecules & Therapeutics
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• 제1권2호
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• pp.177-182
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• 1993

From 84 clinical isolates of Staphylococcus species, ten strains showing inducible resistance to MLS antibiotics were selected by disk agar diffusion method. Colony hybridization was executed using two MLS inducible resistance genes, ermA and ermC, previously identified from S. aureus as probes. S. hemolyticus 401 and S. epidermidis 542 whose genes were not homologous to those probes were finally selected. It was determined that the resistance genes of S. hemolyticus 401 and S. epidermidis 542 were not homologous to ermA, ermC and ermAM by Southern hybridization. S. epidermidis 542 had a plasmid DNA. To know if the plasmid may have genes related to inducible resistance, it was attempted to transform B. subtilis BR151 and S. aureus RN4220 with the plasmid prepared from S. epidermidis 542. It was shown that the gene related to inducible resistance to MLS antibiotics did not exist in this plasmid. These results indicate that two clinical isolates of S. hemolyticus 401 and S. epidermidis 542 had novel genes which were not homologous to MLS resistance genes identified previously. It was assumed that these genes may exist in chromosomal DNA.