• Journal of Apiculture
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• v.34 no.2
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• pp.131-136
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• 2019

Recently, number of honeybees (Apis mellifera) has visibly decreased because they are vulnerable to some diseases like American foulbrood disease. American foulbrood disease, which is caused by Paenibacillus larvae, is emerged as great cause of decrease in number of honeybees. After antibiotic-resistant strain emerged, it is now more difficult to treat those pathogens successfully. Researches on finding alternative antibacterial compound are ongoing. In this study, we examined the antibacterial effect of honokiol on P. larvae. Honokiol showed great antibacterial effect with minimum inhibitory concentration of 12.5 ㎍/mL and minimum bactericidal concentration of 50 ㎍/mL. An agar diffusion test also confirmed the anti-Paenibacillus larvae activity of honokiol with an inhibitory zone of 9±0.5 mm. Since honokiol is known to interact membrane of some bacteria, we measured 260 nm absorbing particles, which could be induced by leakage of cells, and confirmed that the leakage of P. larvae occurred in dose-dependent manners. However, result of crystal violet assay suggested that honokiol has only mild anti-biofilm formation effect on P. larvae, which means honokiol controls the bacteria by inducing the bursting of membrane. Finally, an additive effect of honokiol with tetracycline and terramycin was found using a checkerboard assay with a fractional inhibitory concentration index value of 0.5.

• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.154-161
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• 2010

The aim of this study was to investigate antibacterial activities of essential oil from C. morifolium against four Grampositive bacteria and six Gram-negative bacteria. The antibacterial activity of the oils was determined by agar-well diffusion assay, minimum inhibitory concentration(MIC), and minimum bactericidal concentration(MBC). Essential oil of C. morifolium had a large inhibition zones especially against Salmonella enterica(21 mm) and Bacillus cereus(19 mm). Essential oil of C. morifolium generally showed higher antibacterial activity against Gram-positive bacteria than Gram-negative bacteria. MIC of essential oil from C. morifolium was 5 ${\mu}g/m{\ell}$ against ten food-borne pathogens. MBC values were determined to be from 5 to 20 ${\mu}g/m{\ell}$ against eight bacteria except Salmonella choleraesuis and Listeria monocytogenes. Therefore, the essential oil of C. morifolium and its components have a potent antibacterial activity against food-borne pathogens, and is expected to be used as a novel food preservative.

• Journal of Veterinary Science
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• v.23 no.3
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• pp.48.1-48.12
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• 2022

Background: The poor intracellular concentration of enrofloxacin might lead to treatment failure of cow mastitis caused by Staphylococcus aureus small colony variants (SASCVs). Objectives: In this study, enrofloxacin composite nanogels were developed to increase the intracellular therapeutic drug concentrations and enhance the efficacy of enrofloxacin against cow mastitis caused by intracellular SASCVs. Methods: Enrofloxacin composite nanogels were formulated by an electrostatic interaction between gelatin (positive charge) and sodium alginate (SA; negative charge) with the help of CaCl₂ (ionic crosslinkers) and optimized by a single factor test using the particle diameter, zeta potential (ZP), polydispersity index (PDI), loading capacity (LC), and encapsulation efficiency (EE) as indexes. The formation mechanism, structural characteristics, bioadhesion ability, cellular uptake, and the antibacterial activity of the enrofloxacin composite nanogels against intracellular SASCVs strain were studied systematically. Results: The optimized formulation was comprised of 10 mg/mL (gelatin), 5 mg/mL (SA), and 0.25 mg/mL (CaCl₂). The size, LC, EE, PDI, and ZP of the optimized enrofloxacin composite nanogels were 323.2 ± 4.3 nm, 15.4% ± 0.2%, 69.6% ± 1.3%, 0.11 ± 0.02, and -34.4 ± 0.8 mV, respectively. Transmission electron microscopy showed that the enrofloxacin composite nanogels were spherical with a smooth surface and good particle size distributions. In addition, the enrofloxacin composite nanogels could enhance the bioadhesion capacity of enrofloxacin for the SASCVs strain by adhesive studies. The minimum inhibitory concentration, minimum bactericidal concentration, minimum biofilm inhibitory concentration, and minimum biofilm eradication concentration were 2, 4, 4, and 8 ㎍/mL, respectively. The killing rate curve had a concentration-dependent bactericidal effect as increasing drug concentrations induced swifter and more radical killing effects. Conclusions: This study provides a good tendency for developing enrofloxacin composite nanogels for treating cow mastitis caused by intracellular SASCVs and other intracellular bacterial infections.

• Journal of Korean society of Dental Hygiene
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• v.15 no.4
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• pp.735-741
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• 2015

Objectives: Lentinus edodes is an edible mushroom with a variety of beneficial effects such as antitumor, anti-inflammatory, antioxidant, and immune-modulatory activity. This study was carried out to evaluate the antimicrobial activities of Lentinus edodes extracts against oral-related bacteria. Methods: The antimicrobial activities of this extracts were investigated against S. anginosus, S. sobrinus, S. aureus, S. mutans, S. ratti, S. sanguinis, A. viscosus, A. naeslundii, and A. actinomycetemcomitans by the disc diffusion method, minimum inhibitory concentration (MIC), and growth inhibition. Results: Ethanol extracts had no antimicrobial activities, but acetone extracts showed antimicrobial activities against A. viscosus and A. actinomycetemcomitans and ethyl acetate extracts had effects against S. aureus, S. sanguinis, A. viscosus, and A. actinomycetemcomitans. Conclusions: The inhibitory effect of Lentinus edodes extracts was investigated on the growth of A. viscosus. Ethyl acetate and acetone extracts showed 90% and 77% inhibitory effect, respectively, against A. viscosus for 24 hrs. Ethyl acetate extracts had MIC of 25.0 mg/ml and acetone extracts showed MIC of >25.0 mg/ml.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.354-358
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• 1999

In order to know the antifungal characteristics of saturated fatty acids having 6 to 12 carbons, their minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) were estimated against Saccharomyces cerevisiae. Fatty acids from C6 to C11 exhibited increasing activity with chain length, but C12 fatty acid did not show activity at all. In relation to antifungal modes of actions, fatty acids investigated showed on inhibitory activity toward the plasma membrane H+-ATPase of Saccharomyces cerevisiae. Their inhibitions to the glucose-induced acidification and ATP hydrolysis caused by the proton pump were found to be in common wiht antifungal activities. At the test concentration of 1mM, hexanoic acid (C6) showed the lowest inhibition of about 30%, while undecanoic acid(C11) showed the strongest inhibition of over 90%. In addition, as seen with antifungal activity, the inhibitory activity of dodecanoic acid (C12) was suddenly reduced to less than 50%.

• Journal of dental hygiene science
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• v.18 no.3
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• pp.147-154
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• 2018

This study aimed to evaluate the antimicrobial effects of Acanthopanax sessiliflorum fruit (ASF; Ogaza) extracts on Streptococcus mutans and Streptococcus sobrinus, which are agents that cause dental caries, and on Streptococcus mitis and Streptococcus salivarius, the microbial flora of the oral cavity. The ASF extracts obtained using 70% ethanol were fractionated in the order of ethyl acetate and n-Butanol, concentrated under reduced pressure, and lyophilized to give powdery solvent extracts. The antimicrobial activity of ASF extracts from each solvent was examined using the disk diffusion method. As a result, only those extracts obtained using an ethyl acetate solvent showed antimicrobial activity. These extracts were selected, and the minimum inhibitory concentration was measured by disk diffusion method at various extract concentrations. Results showed a minimum inhibitory concentration of 32 mg/ml. The viable cell count was measured to confirm the minimum bactericidal concentration. Results showed a minimum bactericidal concentration of 64 mg/ml. In the cytotoxicity test using normal human dermal fibroblast cells, the absorbance value of the test group was similar to that of the control group at 0.64, 1.28, and 6.4 mg/ml. The bacteria and their colonies were examined using a scanning electron microscope. Boundaries between the antimicrobial activity region and non-antimicrobial activity region were observed around the paper disk, which was immersed in the extract with 32 mg/ml concentration. Bacterial colonization was not observed in the area with antimicrobial activity. This finding suggests that ASF extracts can inhibit the growth of some microorganisms in the oral cavity, in addition to the effects of these extracts known to date. In particular, ASF extracts may be used as a preparation for preventing dental caries by adding the extract to the toothpaste or oral mouthwash.

• International Journal of Human Ecology
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• v.7 no.1
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• pp.145-153
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• 2006

Hwangryeon (Coptidis rhizoma) was extracted by methanol and its antimicrobial activities against food spoilage and foodborne disease microorganisms were investigated by the paper-disc method. The microorganisms used in this experiment included 5 species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus) and 3 species of fungi (Fusarium solani, Aspergillus flavus, and Penicillium citreonigrum). The Hwangryeon extract showed antimicrobial effect against P. aeruginosa, S. aureus, S. typhimurium, and K. pneumonia. The minimum inhibitory concentration on S. aureus, S. typhimurium, and K. pneumoniae was 300 mg/mL, but on P. aeruginosa it was 200 mg/mL. In the methanol extracts from Hwangryeon, 190 compounds were separated by GC/MS. The extraction yields of phenols, furans, alcohols, acids and esters, ketones, and miscellaneous compounds were 28.10%, 2.67%, 1.79%, 12.89%, and 2.35%, respectively. The phenolic compounds, generally understood to be an antimicrobial active substance, was measured at 28.10%, a relatively remarkable amount.

• Plant Resources
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• v.8 no.2
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• pp.96-102
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• 2005

As part of developing natural food preservatives, the antimicrobial effect of ethanol and water extracts from the Cruciferous vegetable was examined Korean traditional Brassica juncea Coss. was used widely as an ingredient of Kimchi, a natural flavoring and spice for a long time. Antimicrobial activities were examined against 15 microorganisms which were food-born pathogens and/or food poisioning microorganisms and food-related bacteria and yeasts. Ethanol extract from leaf mustard showed an antimicrobial effect in most of the strains used in the present study. The lowest minimum inhibitory concentration (MIC) were seen in Bacillus subtilis and Bacillus natto at 10 mg/ml. MIC of water extract was 40-60 mg/ml for bacteria and yeast. Antimicrobial activity of the ethanol extract was not disappeared by the heating at $121^{\circ}C$ for 15 min and not affected by pH.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.73-78
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• 1982

The optimal conditions of sterilization for Streptococcus pyogenes treated with disinfectant and antibiotics were investigated. The survivors of Streptococcus pyogenes had no effect at the concentration of 0.2% hydrogen peroxide but decreased abruptly when the concentration increased from 0.4% to 1.0% Minimum inhibitory concentration values of 0.78, 0.39 and 3.125 $\mu\textrm{g}$/$m\ell$ for erythromycin, tetracycline and cephalexin, respectively, were obtained for Streptococcus pyogenes when incubated at 37 $^{\circ}C$ for 24 hrs. Tetracycline and cephalexin showed bactericidal effect against Streptococcus pyogenes, whereas erythromycin did bacteriostatic effect.

• Korean Journal of Veterinary Service
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• v.29 no.1
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• pp.19-26
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• 2006

Bee venom is synthesized in the venom gland's of worker and queen bees and stored in their venom sacs. Bee venom is a rich source of enzymes, peptides and biogenic amines. there are at least 18 active components in the venom which have some pharmaceutical properties. This study was performed to evaluate minimum inhibitory concentration(MIC) of bee venom against bacteria isolated from pjgs and chickens with disease. In case of reference strains, the MIC $({\mu}g/m{\ell})$ of Staphylococcus aureus ATCC 6538, Streptococcus mutans ATCC 25175, and Salmonella typhimurium ATCC 6538 were 64, 64 and 32, respectively. In case of bacteria isolated from pig and chicken, the MIC of Staphylococcus aureus, Staphylococcus hyicus and Staphylococcus chromogenes were 8, 128 and 128, and that of 11 strains of Escherichia coli were 8 to >512 and that of 8 strains of Salmonella sup were >512. Antibacterial resistance test of 22 strains isolated from pig and chicken and 3 reference strains were performed by agar gel diffusion method, using 17 antibacterial drugs including penicillin, cefazolin, tetracycline and quinolone group. The multiple drug resistant patterns were found in most strains isolated from pig and chicken.