• Food Science of Animal Resources
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• v.36 no.4
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• pp.452-457
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• 2016

Lactoferrin is a glycoprotein with various biological effects, with antibacterial activity being one of the first effects reported. This glycoprotein suppresses bacterial growth through bacteriostatic or bactericidal action. It also stimulates the growth of certain kinds of bacteria such as lactic acid bacteria and bifidobacteria. In this study, Asn-Leu-Asn-Arg was selected and chemically synthesized based on the partial sequences of bovine lactoferrin tryptic fragments. Synthetic Asn-Leu-Asn-Arg suppressed the growth of Pseudomonas fluorescens, P. syringae and Escherichia coli. P. fluorescens is a major psychrotrophic bacteria found in raw and pasteurized milk, which decreases milk quality. P. syringae is a harmful infectious bacterium that damages plants. However, synthetic Asn-Leu-Asn-Arg did not inhibit the growth of Lactobacillus acidophilus. It is expected that this synthetic peptide would be the first peptide sequence from the bovine lactoferrin C-lobe that shows antibacterial activity.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.297-301
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• 2013

The present study was to investigate anti-microbial effects of curcumin on major bacterial pathogens for farmed fish, such as Aeromonas hydrophila, A. salmonicida subsp. masoucida, A. salmonicida subsp. salmonicida, Edwardsiella tarda, Vibrio vulnificus, V. paraheamolyticus using disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. In disc diffusion test, curcumin exhibited concentration-dependent antimicrobial activities to all bacteria pathogens used in the study. Antimicrobial effects of curcumin was found differently depending on bacterial species when determined by MIC or MBC tests. For examples, E. tarda and A. hydrophila was respectively the most sensitive bacterium for bacteriostatic and bacteriocidal effect of curcumin. Collectively, curcumin could be a potential natural drug for controlling pathogenic bacteria in the aquaculture industry.

• Annals of Clinical Microbiology
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• v.21 no.4
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• pp.80-85
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• 2018

Background: The aim of this study was to comparatively evaluate the bactericidal effects of copper, brass (copper 78%, tin 22%), and stainless steel against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VREFM), and multidrug-resistant Pseudomonas aeruginosa (MRPA). Methods: The isolates (MRSA, VREFM, MRPA) used in this study were mixed wild type 3 strains isolated from patients treated at Uijeongbu St. Mary's Hospital in 2017. These strains showed patterns of multidrug resistance. The lyophilized strains were inoculated into and incubated for 24 hr in tryptic soy broth at $35^{\circ}C$. The initial bacterial inoculum concentration was adjusted to $10^5CFU/mL$. A 100-mL bacterial suspension was incubated in containers made of brass (copper 78%, tin 22%), copper (above 99% purity), and stainless steel at $35^{\circ}C$. Viable counts of bacteria strains were measured for 9 days. Results: In this study, the bactericidal effects of copper and brass on MRSA, VREFM, and MRPA were verified. The bactericidal effect of stainless steel was much weaker than those of copper and brass. The bactericidal effect was stronger on MRPA than on MRSA or VREFM. Conclusion: To prevent cross infection of multidrug resistant bacteria in hospitals, further studies of longer duration are needed for testing of copper materials on objects such as door knobs, faucets, and bed rails.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.69-77
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• 2022

Antimicrobial peptides (AMPs) play an important role in innate immunity against pathogenic infections. AMPs exterminate pathogenic bacteria by disrupting cell membranes or inhibiting intracellular molecules. NK-2, first identified in pigs and derived from NK-lysin, has antimicrobial effects against bacteria and parasites. In this study, chimeric peptides (cpNK) of chicken and pig NK-2 and cpNK-derived peptides (cpNK-a1 and cpNK-a2) were synthesized, and their antimicrobial effects against various pathogenic bacteria such as Escherichia coli, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA) were investigated. The structure of chimeric peptides from chicken and pig NK-2, cpNK, include α-helix like NK-2 and peptide net charge was +9 like porcine NK-2. The cpNK peptide showed powerful bactericidal effects against most bacterial species, including MRSA, especially against gram-negative bacteria. Furthermore, cpNK-derived short peptides, cpNK-a1 and a2 also showed bactericidal activity, but the effects were weaker than those of cpNK. Therefore, we conclude that cpNK- and cpNK-derived short peptides have the potential to be used as antibiotic alternatives.

• Journal of the Korean Chemical Society
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• v.14 no.3
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• pp.207-212
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• 1970

A large variety of weed killers, insecticides, and bactericiedes on the market today are of almost infinite variety, but their pharmacological effects are different from each other according to the objects to cope with. Therefore, it is hoped that some chemical substance which serves as weed killer, an insecticide, and a bactericede at a same time, should be synthesized, in order to save expense and labor. I anticipated that the desire would be met by introducing to a molecule the radical which has the three effects. Here, I made an attempt of introducing $Cl_2$ gas to aniline considering the following respects: 1. Introduction velocity of $Cl_2$ gas under the varied temeratures and velocities of $Cl_2$ gas 2. The effect of reaction period under the condition which gives the most satisfactory yield. 3. The actions of catalysts, $SbCl_3$, $FeCl_3$, and $MoCl_5$, and their proportions when a mixture of the three catalysts is used in producing 2,6-dichloro-aniline. After consideration of above phenomena, the maximum production rate of 79.5% of 2.6-compound was obtained. With the compound I synthesized 2.6-dichloro-4-nitroaniline-mercuric acetate. Investigations of the effects of the compound as weed killer, an insecticide, and a bactericide showed that the compound, 2,6-dichloro-4-Nitro Aniline mercuric acetate has a satisfactory herbi-insecti-bactericidal effect.

• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.507-516
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• 1993

The Chlorhexidine(CHX) has been a widely used adjunt in periodontal therapy due to its bactericidal effect. In spite of the effects of CHX exhibits cytotoxic to human cells and delays granulation tissue formation. Therefore, understanding the effects of CHX on fibroblast attachment and cell growth will provide the rationale for its use during healing phase of periodontal surgery. This study was undertaken to examine the effects of standardized CHX-pretreated dentin slices and direct CHX exposure on human gingival fibroblasts. The results were as follow : 1. In experiment 1, there was a significant reduction in the number of fibroblast attachment in 0.12, 1%-pretreated groups relative to the control, 0.05%-pretreated groups(P<0.05). 2. In experiment 1, the control, 0.05%-pretreated groups showed considerable attachment and typical fibroblastic morphology, but 0.12, 1%-pretreated groups showed irregular, round-up (unattached) fibroblastic morphology. 3. In experiment 2, it appeared that all experimental groups exhibits significant inhibition of cell growth when compared with the control group.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.122-129
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• 2008

The purpose of this work was to investigate the synergically bactericidal effects and cellular responses of green tea polyphenols (TPPs) and nalidixic acid (NA) on nalidixic acid-resistant (NAR) Salmonella typhimurium. The bactericidal activities of $>3,500{\mu}g/ml$ TPPs and $<256{\mu}g/ml$ NA were investigated for S. typhimurium of which initial cell number was approximately adjusted to 107 cell/ml. Complete elimination of NAS-S. typhimurium was achieved within 6 hr of incubation at the concentrations of $3,500{\mu}g/ml$ TPP or $256{\mu}g/ml$ NA, whereas only partial bactericidal effect was achieved under the same conditions. However, the combinations of $3,000{\mu}g/ml$ TPPs and $32{\mu}g/ml$ NA against NAS-S. typhimurium and $3,500{\mu}g/ml$ TPPs and $64{\mu}g/ml$ nalidixic acid against NAR-S. typhimurium showed complete removal within 5 hr of incubation. The stress shock proteins (SSPs) were induced at different concentrations of TPP o rNA used as stressors against cell culture of S. typhimurium. The proteins were identified as 70-kDa DnaK and 60-kDa GroEL by SDS-PAGE and Western blot. SSPs induced by the stressors were found to increase in proportion to the TPPs or NA. Scanning electron microscopy analyses revealed the presence of perforations and irregular rod shape with wrinkled surfaces for cells treated with TPPs or NA.

• Food Science and Preservation
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• v.24 no.6
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• pp.827-833
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• 2017

This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water ($0.2ml{\cdot}L^{-1}$), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4$^{TM}$ (1,3,4%), Fresh produce wash$^{TM}$ (1,3,4%), Cleancol$^{TM}$ (1%), Chitochol$^{TM}$ (1%) and Natural Ca$^{TM}$ (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

• The Journal of the Korean dental association
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• v.22 no.9 s.184
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• pp.793-801
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• 1984

Though oral microgranisms were among the first to be observed by humans, the interest in oral microbiology lagged. When it became apparent that the oral microflora did influence systemic disease of the body, interest was aroused in the nature and kinds of the microgranisms. The risk of infection in dental procedures is due to the abundant flora of the mouth. This hazard can be reduced to some extent by the use of a local disinfectant. The present studies were undertaken to evaluate and compare the various disinfectants which are commonly used in clinics and hospitals. The results were as follows. 1. The bactericidal activity of the disinfectants mainly depends upon the kinds of the agents, not upon the kinds of the microorganisms. 2. In H₂O₂(3%), the bactericidal activity was greatly related to the contact time. So, at least 4 minitues of contract time was required to use it as an oral antiseptic. 3. In ethyl alcohol (70%), Pseudomonas aeruginosa and Streptococcus salivarius surived a little after 15 seconds of contact time, but, no other colony was discovered after more than 15 seconds of contact time in any kins of microorganisms. 4. Merthiolate (0.1%) showed low antibacterial activity, more in Gram-positive organisms and less in Gram-negative organisms. 5. Benzalkonium chloride (0.1%) and povidone-iodine (10%) showed the most excellent results, revealing no surviving organisms only after 14 seconds of contact time.

• Food Science of Animal Resources
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• v.31 no.2
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• pp.311-315
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• 2011

The objective of this study was to evaluate the antimicrobial effects of various natural flavonoids against growth of psychotropic Bacillus cereus strains, which cause dairy food outbreaks. Flavonoids were first screened for their ability to inhibit growth of B. cereus strains using the paper-disc diffusion test. Second, the growth inhibitory effect of selected flavonoids was evaluated in tryptic soy broth supplemented with 0.6% yeast extract, and the bactericidal effect of the flavonoids was measured in 0.8% (w/v) NaCl solution. Based on the paper-disc diffusion test, kaempferol was effectively active against B. cereus P14 and B. cereus KCCM 40935. Kaempferol had an antimicrobial effect at concentrations greater than 100 ${\mu}M$, and the numbers of B. cereus P14 and B. cereus KCCM 40935 decreased by 3.55 and 1.5 log cycles, respectively. The cell numbers of B. cereus P14 and B. cereus KCCM 40935 treated with 50 ${\mu}M$ kaempferol were reduced by 4.18 and 2.84 log cycles during a 24 h incubation to test the bactericidal effect of kaempferol (p<0.05). The results indicate that kaempferol had the greatest antimicrobial effect among the psychotropic B. cereus strains and the natural flavonoids tested.