• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.228-233
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• 2010

Recently, nanoparticles of gold and silver has been applied to various fields due to antimicrobial property. This study added Ag and Au nanoparticles in HEMA (2-hydroxyethylmethacrylate), NVP (N-vinyl pyrrolidone) and MMA (methylmethacrylate) and copolymerized the solution by heating at $70^{\circ}C$ for 40 minutes, $80^{\circ}C$ for 40 minutes, and finally, $100^{\circ}C$ for 40 minutes. Using the polymer produced through the copolymerization process, and measured the physical characteristics which showed water content of 28.43% ~ 35.27%, refractive index of 1.429 ~ 1.440, visible transmittance of 79.2% ~ 86.5% and tensile strength of 0.125 kgf ~ 0.201 kgf. We judged that we made the copolymer with antimicrobial and physical properties which is suitable for conventional contact lens.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.271-279
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• 2015

Lactoferrin (LF) is a multifunctional, iron-binding glycoprotein found in physiological secretions of mammals. LF shows antibacterial, antiviral and antifungal activities. In the present study, a gene encoding the N-terminal lobe of human lactoferrin (hLF) was isolated, cloned and expressed in methylotrophic yeast, Pichia pastoris. The recombinant hLF-N (rhLF-N) protein was secreted into the culture medium at the level of $458{\mu}g/ml$ in 3 L fermentor. The size of purified hLF-N was estimated as 35 kDa when analyzed by SDS-PAGE and western blotting. The rhLF-N was further confirmed by immunodiffusion using the anti-hLF polyclonal antibody. The expression profile analysis by qRT-PCR showed that the relative mRNA expression of rhLF-N was maximal after 2-3 days of methanol induction and reduced gradually at 4 days. The purified rhLF-N showed broad antibacterial activities against the pathogens such as Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Burkholderia cepacia, and Salmonella typhimurium. However, rhLF-N showed relatively lower activity when compared to peptides derived from LF. In spite of this weak activity, the rhLF-N expressed in P. pastoris might be more advantageous for the industrial application, because rhLF-N is secreted into the culture medium and the production can also be increased by optimization of culture conditions.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.90-94
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• 2013

A new Bacillus strain designated as MP56 producing antimicrobial substance has been isolated from the mud flat of Korea. The strain MP56 was found to exhibit broad spectrum of antimicrobial activity against Gram-positive pathogenic microorganisms and MDR (multi drug resistant) strains. The 16S rRNA sequence revealed that the MP56 was closely related to Bacillus subtilis with 99.93% homology. The optimal medium composition for production of antimicrobial substance in the B. subtilis MP56 were 1% mannitol, 1% oat meal, 0.01% $CaCl_2$. Antimicrobial activity of the culture broth against different pathogenic strains was assessed using the antimicrobial spectrum. The result suggests that Bacillus strain MP56 produces high quality antimicrobial substance that might be very useful to control varieties of pathogenic microbial growth.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.618-623
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• 2005

Kimchi was prepared with 2.5% and 5% Monascus purpureus Koji(MPK) paste(20%), fermented at $10^{\circ}C$ for 15 days, and sampled at 3-day intervals during storage. Samples were extracted using 80% ethanol. Ethanol extracts of kimchi prepared with MPK paste (MPK kimchi extracts) and control kimchi extracts at 1mg/mL showed 40% decrease in proliferation of cancer cells, such as AGS, KATOIII, HepG2, and Hela. MPK kimchi extracts showed highest cytotoxic effect against cancer cells compared with control at 2mg/mL. Antibacterial effect of MPK kimchi extracts decreased during fermentation, and was higher than that of control kimchi extracts during fermentation, particularly after six days. The 5% MPK kimchi extracts showed higher antibacterial activity against Escherichia coli O157:H7 and Vibrio parahaemolyticus than other groups. Results indicate kimchi added with M. purpureus Koji paste has stronger antibacterial and anticancer effects in vitro than control kimchi.

• Journal of the Korean Society of Food Culture
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• v.22 no.2
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• pp.266-273
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• 2007

This study was conducted to examine the antimicrobial activity of Perilla frutescens var. acuta leaf fractions extracted with a mixture of ethanol and water. The Ca and Mg contents of the leaf were 595.75 mg% and 467.0 mg%, respectively, and they were the highest among all of the test minerals. The extract yield increased w e content of water in e extraction solvent. Antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa was found in the 50,70 and 95% ethanol extracts. Of the various fractions extracted from the mixture of ethanol and water, the ethyl acetate fraction showed antibacterial activity against all microorganisms tested in this experiment, and the antibacterial activity of ethyl acetate fraction from the water extract was the strongest. The phenol and flavonoid content in the ethyl acetate fraction showed no correlation with the concentration of ethanol in the extract solvent; however, their contents were higher in the 30% ethanol and water extraction which the antimicrobial activity of the extract was the strongest.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.166-173
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• 1997

1993년부터 1995년까지 약 3개년 동안 우리 나라에서 사육하고 있는 가축의 유병율을 조사한 결과, 닭 16,200수 중에서 54수(0.3%)가 괴사성 장염에 이환 되었으며 새끼돼지 620두 중에서 9두(13.8%)가 장독혈증에 이환 되었다. C. perfringens의 분리율을 조사한 결과, 괴사성 장염에 이환 되어있는 닭 54수 중 7수(13.0%)에서 본균이 분리되었으며 장독혈증에 이환 되어있는 새끼돼지 66두 중 14두(21.2%)에서 본균이 분리되었고 장독혈증에 이환 되어있는 소 9두 중 3두(33.3%)에서 본균이 분리되었다. Acriflavine을 이용하여 C. perfringens의 S-R변이를 조사한 결과, S-R변이는 mercuric chloride, nicotine, caffeine, cysteine, glucose 등의 순으로 나타났는데, 이중 mercuric chloride가 가장 감수성이 높았다. C. perfringens의 항균요법제에 대한 감수성은 cepalothin, penicillin, erythromycin, amikacin 등이 높은 감수성을 나타내었는데, S-R변이 후에는 감수성이 일반적으로 저하되는 경향이었다. 중화시험법을 이용하여 C. perfringens의 독소형을 분류한 결과, cd 24균주 중 22균주(91.7%)는 A형이었으며 2균주(8.3%)는 C형이었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.4
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• pp.167-172
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• 2019

The strength (MPa), hardness (Hv), shrinkage (%) and biological properties of the HAp were measured by using an organic plasticizer which facilitates the molding and heat treatment. Mechanical properties such as compressive strength, bending strength and hardness were increased with increasing amount of plasticizer, but mechanical properties were decreased when plasticizer was added more than 7 %. This is because addition of the plasticizer above the allowable value causes cracking during molding, and such cracks promote the generation of microcracks and pores at the time of sintering, resulting in a decrease in mechanical properties. As a result of the antimicrobial activity test, no bacteria were detected regardless of the addition amount of plasticizer.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.438-443
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• 2006

Antibacterial effects of six volatile essential oils against Vibrio sp. were evaluated. Volatile components of essential oil were analyzed by gas chromatography and gas chromatography mass spectrometry. Ginger oil treatment inhibited growth of V. parahaemolyticus by 22.5-85.7%. Main volatile compounds of ginger oil were ${\beta}-bisabolene$ (35.19%, peak area) and ${\beta}-sesquiphellandrene$ (12.22%). V. parahaemolyticus was completely inhibited at 1,000 ppm by treatment with mustard oil. Tolerances of V. vulnificus 01 and 02 were twice higher than that of V. parahaemolyticus. Main volatile compound of mustard oil was allyl isothiocyanate (92.55%). Garlic oil treatment of 1,000 ppm inhibited growths of V. parahaemolyticus, V. vulnificus 01, and V. vulnificus 02 by 22.8, 14.6, and 32.9%, respectively. Main volatile compounds of garlic oil were dimethyl sulfide (49.39%) and methyl 2-propenyl disulfide (10.09%). Growth of V. vulnificus 02 was inhibited by 60.6-80.3% via treatment with bud, leaf, and whole oil of clove. Antibacterial activity of whole clove oil on V. vulnificus 02 was stronger than those of ginger, mustard, and garlic oil. Main volatile compounds were eugenol (83.33%) and ${\beta}-caryophyllene$ (7.47%) in clove bud, eugenol (87.46%) and ${\beta}-caryophyllene$ (10.03%) in clove leaf, and eugenol (86.04%) and ${\beta}-caryophyllene$ (9.71%) in whole clove. These results revealed essential oils from spices could be used as potential agents to inhibit Vibrio sp.

• Journal of fish pathology
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• v.23 no.1
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• pp.37-45
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• 2010

In this study, we carried out research on the level of single and multi-drug resistance of bacteria isolated from cultured flounder Paralichthys olivaceus. One hundred sixty one bacteria were isolated from cultured olive flounder Paralichthys olivaceus in Korea and the isolates consisted of Edwardsiella tarda (n=32), Vibrio ichthyoenteri (n=37), Vibrio spp. (n=54), Streptococcus parauberis (n=28) and Streptococcus spp. (n=10). These E. tarda isolates were highly resistant in the order of tetracycline (84.4%) and oxolinic acid (71.9%). V. ichthyoenteri and Vibrio spp. showed resistance ampicillin (94.6% and 81.5%) and tetracycline (56.8% and 42.6%). S. parauberis isolates were resistant ampicillin (57.1%), tetracycline (57.1%) and erythromycin (35.7%). Of the isolates, 84.4% of E. tarda, 73.0% of V. ichthyoenteri, 57.4% of Vibrio spp., 42.8% of S. parauberis and 70.0% of Streptococcus spp. isolates exhibited multi-drug resistance against more than two antibiotics.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.293-299
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• 2012

The residual contents of fluoroquinolones in fish and shrimp were analyzed by using HPLC-FLD and LC-MS. The limit of detection (LOD) and limit of quantification (LOQ) for fluoroquinolones by HPLC-FLD were 0.0030-0.0083 and 0.0090-0.0252 mg/kg, respectively. Those by LC-MS were 0.0019-0.0040 and 0.0059-0.0122 mg/kg, respectively. Recoveries regarding ofloxacin, norfloxacin, pefloxacin, ciprofloxacin and enrofloxacin ranged from 76.4-104.6%. The detection rate of fluoroquinolones was 7.5% from a total of 268 samples. In only one Korean bullhead sample, the sum of ciprofloxacin and enrofloxacin contents was detected at a higher level than its maximum residue limits (MRL) of 0.1 mg/kg. Ofloxacin, norfloxacin and pefloxacin were not detected in any samples and detection rates of ciprofloxacin and enrofloxacin were 3.4% and 6.7%, respectively. In detection rate by species eel (2.6%), loach (2.2%), Korean bullhead (1.5%), carp (0.7%) and snakehead (0.4%) were in order.