• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.72-76
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• 1972

Seven new hydroxyamine derivatives of 2,2'-methylene bis(3,4,6-trichloroacetoxy benzene) were synthesized by the Mannich reactions. 13 strains of microorganisms were tested for sensitivity to these derivatives by both paper disk method and tube dilution method. Of these compounds, -NHOH compound displays the most effective antimicrobial activity in vitro against Brevibacterium ammoniagenes, Staphylococcus aureus and Bacillus subtilis. Its minimal inhibitory concentration is $1.6{\mu}g/ml$ for Brevibacterium ammoniagenes, and $5{\mu}g/ml$ for Staphylococcus aureus and Bacillus subtilis.

• Korean Journal of Medicinal Crop Science
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• v.18 no.2
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• pp.105-112
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• 2010

Korean Sophora japonica has been found to posses an anti-inflammatory activity. In this study, Korean Sophora japonica extract, rutin, was used to know whether rutin inhibits to produce inflammatory mediators NO and TNF-$\alpha$ from the mouse peritoneal macrophages that were treated an inflammatory agent LPS. The rutin-1 hr pretreated macrophages were incubated with LPS for 0.5~5 hrs, and then collected the supernatant and the cell lysate for measurements of the level of iNOS, NO, TNF-$\alpha$ mRNA, TNF-$\alpha$, and p-NF-${\kappa}B$. Minimal and maximal effective doses of the rutin on them were 1 and $100{\mu}g/ml$, respectively. The maximal effective dose of rutin certainly inhibted the productions of iNOS, NO, TNF-$\alpha$ mRNA, TNF-$\alpha$and p-NF-${\kappa}B$ from the LPS-treated macrophages (p<0.0001). Its $ED_{50}$ for inhibition of TNF-$\alpha$ mRNA and p-NF-${\kappa}B$ was $5{\mu}g/m{\ell}$, and for iNOS, NO, and TNF-$\alpha$ was $10{\mu}g/m{\ell}$. The rutin did not have any cytotoxic effect. As the results, the Sophora japonica rutin could be a good candidate for an anti-inflammatory action.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.450-455
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• 1997

The preparation of Bacillus coagulans is used as a therapeutics for human intestinal disorders. However, the bacterium in the preparation is very susceptible to rifampic in and fluoroquinolones. When the preparation is taken with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. So B. coagulans RFR17 resistant to rifampicin was obtained by treating the parent B. coagulans with N-methyl-N'-nitro-N-nitrosoguanidine. B. coagulans OFR17 was produced by serial passage of B. coagulans RFR17 on agar with 2-fold minimal inhibitory concentration of ofloxacin or ciprofloxacin. B. coagulans OFR17 was resistant to fluoroquinolones up to 16~64 fold higher than that for the original strain. B. coagulans OFR17 also exhibited identical characteristics with the parent strain when they were tested for lactic acid production and growth inhibition of E. coli MB4-01 and Shigella sonnei MB4-10411. From in vitro test, it was also identified that rifampicin and ofloxacin are not inactivated by certain factors of B. coagulans OFR17. Conclusively, B. coagulans OFR17 can be regarded as a promising strain which can be developed as the preparation for the treatment of the intestinal disorders of the tuberculosis patients under rifampicin and ofloxacin therapy.

• The Korean Journal of Health Service Management
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• v.13 no.2
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• pp.135-142
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• 2019

Objectives: The objective of this study was to assess the antimicrobial effect of Platycodon grandiflorum extracts against oral microorganisms. Methods: The anti-microbial activity and minimal inhibitory concentration were measured the agar dilution method. Results: Platycodon grandiflorum extracts grew in the free agar plates all of the oral microorganisms. In the bark-free Platycodon grandiflorum extracts all the oral microorganisms grew in the free agar plates. Growth was inhibited at a concentration of 0.5 mg/ml. Oral microorganisms showed an absence of growth at a concentration of 1 mg/ml. Conclusions: It was confirmed that the extracts of Platycodon grandiflorum having a higher saponin content than the bark - free Platycodon grandiflorum extract showed excellent antimicrobial effect.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.733-739
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• 2021

Acinetobacter strains are widely present in the environment. Some antimicrobial-resistant strains of this genus have been implicated in infections acquired in hospitals. Genetic similarities have been reported between Acinetobacter strains in nosocomial infections and those isolated from foods. However, the antimicrobial resistance of Acinetobacter strains in foods, such as meat, remains unclear. This study initially aimed to isolate Campylobacter strains; instead, strains of the genus Acinetobacter were isolated from meat products, and their antimicrobial resistance was investigated. In total, 58 Acinetobacter strains were isolated from 381 meat samples. Of these, 32 strains (38.6%) were from beef, 22 (26.5%) from pork, and 4 (4.8%) from duck meat. Antimicrobial susceptibility tests revealed that 12 strains were resistant to more than one antimicrobial agent, whereas two strains were multidrug-resistant; both strains were resistant to colistin. Cephalosporin antimicrobials showed high minimal inhibitory concentration against Acinetobacter strains. Resfinder analysis showed that one colistin-resistant strain carried mcr-4.3; this plasmid type was not confirmed, even when analyzed with PlasmidFinder. Analysis of the contig harboring mcr-4.3 using BLAST confirmed that this contig was related to mcr-4.3 of Acinetobacter baumannii. The increase in antimicrobial resistance in food production environments increases the resistance rate of Acinetobacter strains present in meat, inhibits the isolation of Campylobacter strains, and acts as a medium for the transmission of antimicrobial resistance in the environment. Therefore, further investigations are warranted to prevent the spread of antimicrobial resistance in food products.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.808-816
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• 2018

Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at $1/2{\times}MIC/FIC$ concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at $1/4{\times}FIC$ concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p< 0.01) at $1/2{\times}MIC/FIC$ concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the $1/4{\times}FIC$ concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.

• Journal of Microbiology and Biotechnology
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• v.32 no.1
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• pp.46-55
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• 2022

Clostridioides difficile infection (CDI) is a significant cause of hospital-acquired and antibiotic-mediated intestinal diseases and is a growing global public health concern. Overuse of antibiotics and their effect on normal intestinal flora has increased the incidence and severity of infections. Thus, the development of new, effective, and safe treatment options is a high priority. Here, we report a new probiotic strain, Bacillus amyloliquefaciens (BA PMC-80), and its in vitro/in vivo anti-C. difficile effect as a prospective novel candidate for replacing conventional antibiotics. BA PMC-80 showed a significant anti-C. difficile effect in coculture assay, and its cell-free supernatant (CFS) also exhibited a considerable anti-C. difficile effect with an 89.06 ㎍/ml 50% minimal inhibitory concentration (MIC) in broth microdilution assay. The CFS was stable and equally functional under different pHs, heat, and proteinase treatments. It also exhibited a high sensitivity against current antibiotics and no toxicity in subchronic toxicity testing in hamsters. Finally, BA PMC-80 showed a moderate effect in a hamster CDI model with reduced infection severity and delayed death. However, further studies are required to optimize the treatment condition of the hamster CDI model for better efficacy and identify the antimicrobial compound produced by BA PMC-80.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.816-823
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• 2022

The rapid spread of superbugs leads to the escalation of infectious diseases, which threatens public health. Endolysins derived from bacteriophages are spotlighted as promising alternative antibiotics against multi-drug resistant bacteria. In this study, we isolated and characterized the novel Salmonella typhimurium phage PBST08. Bioinformatics analysis of the PBST08 genome revealed putative endolysin ST01 with a lysozyme-like domain. Since the lytic activity of the purified ST01 was minor, probably owing to the outer membrane, which blocks accessibility to peptidoglycan, antimicrobial peptide cecropin A (CecA) was fused to the N-terminus of ST01 to disrupt the outer membrane. The resulting CecA::ST01 has been shown to have increased bactericidal activity against gram-negative pathogens including Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, and Enterobacter cloacae and the most affected target was A. baumannii. In the presence of 0.25 µM CecA::ST01, A. baumannii ATCC 17978 strain was completely killed and CCARM 12026 strain was wiped out by 0.5 µM CecA::ST01, which is a clinical isolate of A. baumannii and resistant to multiple drugs including carbapenem. Moreover, the larvae of Galleria mellonella could be rescued up to 58% or 49% by the administration of CecA::ST01 upon infection by A. baumannii 17978 or CCARM 12026 strain. Finally, the antibacterial activity of CecA::ST01 was verified using 31 strains of five gram-negative pathogens by evaluation of minimal inhibitory concentration. Thus, the results indicate that a fusion of antimicrobial peptide to endolysin can enhance antibacterial activity and the spectrum of endolysin where multi-drug resistant gram-negative pathogens can be efficiently controlled.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.78.1-78.13
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• 2022

Background: Florfenicol might be ineffective for treating Staphylococcus aureus small colony variants (SCVs) mastitis. Objectives: In this study, florfenicol-loaded chitosan (CS)-sodium tripolyphosphate (TPP) composite nanogels were prepared to allow targeted delivery to SCV infected sites. Methods: The formulation screening, the characteristics, in vitro release, antibacterial activity, therapeutic efficacy, and biosafety of the florfenicol composite nanogels were studied. Results: The optimized formulation was obtained when the CS and TPP were 10 and 5 mg/mL, respectively. The encapsulation efficiency, loading capacity, size, polydispersity index, and zeta potential of the optimized florfenicol composite nanogels were 87.3% ± 2.7%, 5.8% ± 1.4%, 280.3 ± 1.5 nm, 0.15 ± 0.03, and 36.3 ± 1.4 mv, respectively. Optical and scanning electron microscopy showed that spherical particles with a relatively uniform distribution and drugs might be incorporated in cross-linked polymeric networks. The in vitro release study showed that the florfenicol composite nanogels exhibited a biphasic pattern with the sustained release of 72.2% ± 1.8% at 48 h in pH 5.5 phosphate-buffered saline. The minimal inhibitory concentrations of commercial florfenicol solution and florfenicol composite nanogels against SCVs were 1 and 0.25 ㎍/mL, respectively. The time-killing curves and live-dead bacterial staining showed that the florfenicol composite nanogels were concentration-dependent. Furthermore, the florfenicol composite nanogels displayed good therapeutic efficacy against SCVs mastitis. Biological safety studies showed that the florfenicol composite nanogels might be a biocompatible preparation because of their non-toxic effects on the renal tissue and liver. Conclusions: Florfenicol composite nanogels might improve the treatment of SCV infections.

• The Plant Pathology Journal
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• v.38 no.5
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• pp.461-471
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• 2022

Erwinia amylovora is a causative pathogen of fire blight disease, affecting apple, pear, and other rosaceous plants. Currently, management of fire blight relies on cultural and chemical practices, whereas it has been known that few biological resources exhibit disease control efficacy against the fire blight. In the current study, we found that an SFC20201208-M01 fungal isolate exhibits antibacterial activity against E. amylovora TS3128, and the isolate was identified as a Penicillium brasilianum based on the 𝛽-tubulin (BenA) gene sequence. To identify active compounds from the P. brasilianum culture, the culture filtrate was partitioned with ethyl acetate and n-butanol sequentially. From the ethyl acetate layer, we identified two new compounds (compounds 3-4) and two known compounds (compounds 1-2) based on spectroscopic analyses and comparison with literature data. Of these active compounds, penicillic acid (1) exhibited promising antibacterial activity against E. amylovora TS3128 with a minimal inhibitory concentration value of 25 ㎍/ml. When culture filtrate and penicillic acid (125 ㎍/ml) were applied onto Chinese pearleaf crab apple seedlings prior to inoculation of E. amylovora TS3128, the development of fire blight disease was effectively suppressed in the treated plants. Our results provide new insight into the biocontrol potential of P. brasilianum SFC20201208-M01 with an active ingredient to control fire blight.