• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.516-520
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• 2018

Bacteriocin is a proteinaceous compound produced by microorganisms showing antimicrobial activities. In this study, the physicochemical properties of the bacteriocin produced by Enterococcus faecium CJNU 2008 strain were characterized. Partially purified bacteriocin showed stabilities against heat treatments at $100^{\circ}C$ for 30 min and $121^{\circ}C$ for 15 min and against solvents treatments such as methanol, ethanol, acetone, acetonitrile and chloroform. The bacteriocin also exhibited stabilities against lipase and ${\alpha}-amylase$ treatments but the stability was abolished at protease treatment, indicating that the antimicrobial agent from E. faecium CJNU 2008 was a proteinaceous bacteriocin. The bacteriocin also showed bactericidal mode of action against Listeria monocytogenes. The molecular mass of the bacteriocin was estimated to be under 6.5 kDa by a tricine-SDS-PAGE analysis. The bacteriocin was purified by HPLC. Further studies toward biochemical analysis of the bacteriocin are needed in near future.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1195-1208
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• 2022

Silver nanoparticles (AgNPs) have potential applications in medicine, photocatalysis, agriculture, and cosmetic fields due to their unique physicochemical properties and strong antimicrobial activity. Here, AgNPs were synthesized using actinobacterial SL19 strain, isolated from acidic forest soil in Poland, and confirmed by UV-vis and FTIR spectroscopy, TEM, and zeta potential analysis. The AgNPs were polydispersed, stable, spherical, and small, with an average size of 23 nm. The FTIR study revealed the presence of bonds characteristic of proteins that cover nanoparticles. These proteins were then studied by using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and identified with the highest similarity to hypothetical protein and porin with molecular masses equal to 41 and 38 kDa, respectively. Our AgNPs exhibited remarkable antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. The combined, synergistic action of these synthesized AgNPs with commercial antibiotics (ampicillin, kanamycin, streptomycin, and tetracycline) enabled dose reductions in both components and increased their antimicrobial efficacy, especially in the case of streptomycin and tetracycline. Furthermore, the in vitro activity of the AgNPs on human cancer cell lines (MCF-7, A375, A549, and HepG2) showed cancer-specific sensitivity, while the genotoxic activity was evaluated by Ames assay, which revealed a lack of mutagenicity on the part of nanoparticles in Salmonella Typhimurium TA98 strain. We also studied the impact of the AgNPs on the catalytic and photocatalytic degradation of methyl orange (MO). The decomposition of MO was observed by a decrease in intensity of absorbance within time. The results of our study proved the easy, fast, and efficient synthesis of AgNPs using acidophilic actinomycete SL19 strain and demonstrated the remarkable potential of these AgNPs as anticancer and antibacterial agents. However, the properties and activity of such particles can vary by biosynthesized batch.

• Korean Journal of Pharmacognosy
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• v.53 no.2
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• pp.87-95
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• 2022

Methicillin resistance Staphylococcus aureus (MRSA) is a gram-positive bacterium, the most commonly isolated bacterial human pathogen. JiYu-san is one of the natural products used to treat diseases in the folk recipe. In this study, we investigated the antimicrobial activity of EtOH 70% extracts of JiYu-san (JYS) against MRSA. The antibacterial activity of JYS against MRSA strain was evaluated using minimum inhibitory concentration (MIC), checkerboard dilution test, and time-kill assay. The effect of JYS on the immune mechanism of MRSA was confirmed through cell membrane permeability tests and energy metabolism tests, and the antibacterial activity mechanism was performed using qRT-PCR and western blot. As a result, in the antibacterial test of JYS, the MIC was measured to be 1.9~1000 ㎍/mL, and synergistic or showed a partial synergistic effect. In addition, JYS showed antibacterial activity in a combination test with DCCD or TX-100. In a study on the mechanism of action of antibacterial activity, it was found that JYS suppressed MRSA resistance genes and proteins. These results suggest that JYS has antibacterial activity and provides great potential as a natural antibiotic by modulating the immune mechanism against MRSA.

• Journal of fish pathology
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• v.9 no.1
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• pp.65-77
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• 1996

Tachyplesin I is an antimicrobial peptide isolated from horseshoe crab. To investigate the mechanism of action of tachyplesin I for phospholipid bilayers, tachyplesin I and five analogs have been synthesized by the solution method. The synthesized five analogs are [$Phe^2$]-tachyplesin I, [$Phe^{8,13}$]-tachyplesin I, [$Cys(Acm)^{3,7,12,16}$]-tachyplesin I with no disulfide bonds, 7(Acm) and 10 (Acm) which denote the fragments [$Cys(Acm)^{3,7,12,16}$]-tachyplesin I. Circular dichroism spectra showed that tachyplesin I took an antiparallel $\beta$-structure in buffer solution and a less ordered structure in acidic liposomes. The carboxyfluorescein leakage experiment indicated that tachyplesin I interacted strongly with neutral and acidic phospholipid bilayers. In fluorescence experiment, the hydrophobic part of the peptide was shown to be embedded in lipid bilayers. All the peptides except for 7(Acm) and 10(Acm) were almost equally active in lipopolysaccharide binding. Therefore, the present study suggested that phospholipid bilayers induced a conformational change of tachyplesin I from the stable $\beta$-structure to a less ordered one.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.2
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• pp.1-13
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• 2015

Objectives Methicillin-Resistant Staphylococcus aureus (MRSA) is a human pathogen and a major cause of hospital-acquired infections. New antibacterial agents that have not been compromised by bacterial resistance are needed to treat MRSA-related infections. In this study, we investigated the antimicrobial activity ofethanol extract of Haedokgeumhwa-san (HGH) which prescription is composed of korean medicine against MRSA. Methods The antibacterial activity of HGH extract was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method (minimal inhibitory concentration; MIC), checkerboard dilution test, and time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors. The checkerboard dilution test was used to examined synergistic effect of ampicillin, oxacillin, ciprofloxacin, vancomycin, gentamicin and norfloxacin in combination with HGH ethanol extract. A time-kill assay was performed a survival curve which was obtained by plotting viable colony counts depending on time on bacterial growth. Results The minimum inhibitory concentration (MIC) of ethanol extract (HGH) ranged from 1,000 to $2,000{\mu}g/mL$ against all the tested bacterial strains, respectively. We are able to confirm that HGH extract has potentially strong antibacterial activity. In the checkerboard dilution test, fractional inhibitory concentration index of HGH in combination with antibiotics indicated synergy or partial synergism against S. aureus. A time-kill study showed that the growth of the tested bacteria was considerably inhibited after 8 hr of treatment with the combination of HGH with selected antibiotics. For measurement of cell membrane permeability, HGH $250{\sim}1,000{\mu}g/mL$ along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (Tris) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide ($NaN_3$) was used as an inhibitor of ATPase. TX, Tris, DCCD and $NaN_3$ cooperation against S. aureus showed synergistic action. Accordingly, antimicrobial activity of HGH was affected by cell membrane and inhibitor of ATPase. Conclusions These results suggest that Haedokgeumhwa-san extract has antibacterial activity, and that HGH extract offers a potential as a natural antibiotic against MRSA.

• Journal of Life Science
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• v.29 no.2
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• pp.181-190
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• 2019

The purpose of this study was to acquire the active compounds of Anisi stellati fructus (ASF) and to analyze the genes and diseases it targets, focusing on its antibacterial effects using a system pharmacological analysis approach. Active compounds of ASF were obtained through the Traditional Chinese Medicine Systems Pharmacology (TCMSP) Database and Analysis Platform. This contains the pharmacokinetic properties of active compounds and related drug-target-disease networks, which is a breakthrough in silico approach possible at the network level. Gene information of targets was gathered from the UnitProt Database, and gene ontology analysis was performed using the David 6.8 Gene Functional Classification Tool. A total of 201 target genes were collected, which corresponded to the nine screened active compounds, and 47 genes were found to act on biological processes related to antimicrobial activity. The representative active compounds involved in antibacterial action were luteolin, kaempferol, and quercetin. Among their targets, Chemokine ligand2, Interleukin-10, Interleukin-6, and Tumor Necrosis Factor were associated with more than three antimicrobial biological processes. This study has provided accurate evidence while saving time and effort to select future laboratory research materials. The data obtained has provided important data for infection prevention and treatment strategies.

• The Korea Journal of Herbology
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• v.30 no.5
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• pp.15-21
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• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/mL along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (TRIS) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.279-285
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• 2006

Thirty dairy cows with pododermatitis were selected and treatment effect of ozone ointment for bovine pododermatitis was investigated. In addition, bactericidal effect of ozone ointment on etiological agent of bovine pododermatitis was evaluated. The pathohistological examination for the pododermatitis, according to application with ozone ointment was investigated. Thirty dairy cows were divided two groups: control group(vaseline group: 15 cows), treatment group(ozone ointment group: 15 cows). Various parameters were evaluated in terms of the lameness score, swelling score, lesion score, WBC, neutrophil, pathohistological finding, and antimicrobial action. As compared with vaseline group, ozone ointment group revealed significant decrease of lameness(p<0.05), swelling(p<0.01) and lesion score(p<0.05) were shown in hoof lesions on 14 days after application. In hematological findings, WBC count revealed slightly high values within normal range before treatment, however, this was 1Corresponding author improved on 14 days after application of ozone ointment. The number of neutrophils was slightly higher than that of normal, however, this was improved on 14 days after application of ozone ointment. In pathohistological findings, normal dermal tissue was found in tissues with pododermatitis on 14 days after application of ozone ointment. In antimicobial action, marked decrease rate of bacteria was observed in feet of all cases treated with ozone ointment. The decreasing rate of bacteria in anaerobic culture was higher than that in aerobic culture.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.272-278
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• 2006

This study was carried out to determine therapeutic the effect of ozonated water therapy on bovine pododermatitis. In addition, bactericidal effect of ozonated water on etiological agent of bovine pododermatitis was examined. The pathohistological examination for the pododermatitis, according to application with ozonated water and ozone ointment was investigated. Thirty healthy cattle were divided two groups(each of 15) : control group(povidone group), treatment group(ozone solution group). Various parameters were evaluated in terms of the lameness score, swelling score, lesion score, WBC count, neutrophil count, pathohistological finding, and antimicrobial action. The decrease of lameness and lesion score were shown in hoof lesions on 14 days after application of ozonated water. Significant decrease of swelling was shown in hoof lesions on 14 days 1Corresponding author after application of ozonated water(p<0.01). In hematological findings, WBC count revealed values within normal range. The number of neutrophils was slightly higher than that of normal, however, this was improved on 14 days after application of ozonated water. In pathohistological findings, recovery was rapid macroscopically and microscopically in the treatment with ozonated water on the hoof lesions and ozonated water was effective. In antimicobial action, bactericidal effect was observed in treatment with ozonated water on the hoof lesions and ozonated water was effective.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.932-945
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• 2009

Several species of Gram-positive bacteria have cell wall peptidoglycan (syn. murein) in which not all of the sugar moieties are N-acetylated. This has recently been shown to be a secondary effect, caused by the action of a peptidoglycan N-acetylglucosamine deacetylase. We have found that the opportunistic pathogen Listeria monocytogenes is unusual in having three enzymes with such activity, two of which remain in the cytoplasm. Here, we examine the enzyme (PgdA) that crosses the cytoplasmic membrane and is localized in the cell wall. We purified a hexa-His-tagged form of PgdA to study its activity and constructed a mutant devoid of functional Lmo0415 (PgdA) protein. L. monocytogenes PgdA protein exhibited peptidoglycan N-acetylglucosamine deacetylase activity with natural substrates (peptidoglycan) from both L. monocytogenes and Escherichia coli as well as the peptidoglycan sugar chain component N-acetylglucosamine, but not with N-acetylmuramic acid. As was reported recently [6], inactivation of the structural gene was not lethal for L. monocytogenes nor did it affect growth rate or morphology of the cells. However, the pgdA mutant was more prone to autolysis induced by such agents as Triton X-100 and EDTA, and is more susceptible to the cationic antimicrobial peptides (CAMP) lysozyme and mutanolysin, using either peptidoglycan muramidases or autolysis-inducing agents. The pgdA mutant was also slightly more susceptible than the wild-type strain to the action of certain beta-lactam antibiotics. Our results indicate that protein PgdA plays a protective physiological role for listerial cells.