• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.229-235
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• 2013

In an effort to develop biopolymer-based antioxidant and antibacterial materials, a chitosan-phloroglucinol conjugate was prepared and cellular antioxidant activity and minimum inhibitory concentration against foodborne pathogens and methicillin-resistant Staphylococcus aureus (MRSA) evaluated. The chitosan-phloroglucinol conjugate showed higher antioxidant activities than the unmodified chitosan (P < 0.05). The chitosan-phloroglucinol conjugate showed 62.29% reactive oxygen species scavenging activity, 56.11% lipid peroxidation inhibition activity, and 2.21-fold increase of glutathione expression in mouse macrophage cells. Additionally, the chitosan-phloroglucinol conjugate exhibited higher antibacterial activities than the unmodified chitosan, and the chitosan-phloroglucinol conjugate showed fourfold higher antibacterial activities against MRSA and clinical isolates and twofold higher activities against foodborne pathogens compared to the unmodified chitosan.

• Korean Journal of Pharmacognosy
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• v.32 no.1 s.124
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• pp.55-60
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• 2001

The comparison of $IC_{50}$ values of Salvia plebeia R. Br. extracts on L1210, $P388D_1$ cancer and Vero normal cell lines showed that the n-hexane soluble extract of S. plebeia R. Br. retains the most growth-inhibitory activity against tumor cell lines. The minimum inhibitory concentration (MIC) of the extract against microorganisms were also examined. Antimicrobial activity of amocla and ketoconazole as references was compared to those of other solvent extracts such as $H_2O$, n-hexane, chloroform, ethyl acetate and methanol. The antimicrobial activity of extract had growth inhibition activity against gramnegative bacteria, gram-positive bacteria and fungi $(MIC\;>\;200\;{\mu}g/ml)$ except for n-hexane extract. Seven bacterial strains were tested for in vitro susceptibility to the extract of S. plebeia R. Br. However the n-hexane extract of S. plebeia R. Br. inhibited the growth of several bacterial strains (MIC values between 100 and $200\;{\mu}g/ml$ for gram positive bacteria, $25\;{\mu}g/ml$ for P. putida).

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.40-44
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• 2018

An isolate capable of inhibiting the growth of gram-positive bacteria was obtained from the soil of Mushim stream, Cheongju. The isolate was identified as Pseudomonas otitidis PS by 16S rRNA gene sequence analysis. P. otitidis PS produced antibiotics as a secondary metabolite when cultured in 1% soybean meal with 0.5% glucose. The maximum yield was about 0.1%. The antibiotic substance of P. otitidis PS extracted using ethyl acetate displayed a minimum inhibitory concentration of $2{\mu}g/ml$ for Staphylococcus aureus KCTC 1261. The antibiotic substance produced an orange halo on chrome azurol S agar due to siderophore activity. Growth inhibition was decreased when the iron was depleted. Since the antibiotic activity was lost upon the addition of the reducing agent ascorbic acid or during anaerobic culture, it was considered that antibiotic of P. otitidis PS strain exerts its bactericidal effect by the generation of reactive oxygen species.

• KSBB Journal
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• v.25 no.2
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• pp.123-129
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• 2010

An endospore-forming, rod-shaped bacterium was isolated from forest soil samples collected at the Taebaek mountain of Gangwon province, Korea, and taxonomically characterized by physiological, biochemical and phylogenetic methods. Its 16S rRNA sequences showed the maximum similarity of 97% with B. amyloliquefaciens. In addition, the isolate BCNU 2002 was determined to have the ability to produce enzymes such as amylase, protease, gelatinase and catalase. The in vitro antifungal activity of Bacillus sp. BCNU 2002 was also examined against human pathogenic fungi such as Aspergillus niger, Candida albicans, Epidermophyton floccosum, Saccharomyces cerevisiae, Trichophyton mentagrophytes and Trichophyton rubrum. A maximum production level of antifungal substances of Bacillus sp. BCNU 2002 was achieved under aerobic incubation at $28^{\circ}C$ for 7 days in LB broth. BCNU 2002 showed strong antifungal activities against T. mentagrophytes and T. rubrum with the range of percentage inhibition from 56.25 to 63.23%. It was also confirmed that ethylacetate extract of cultured broth showed a strong antifungal activity against A. niger, C. albicans, S. cerevisiae and T. rubrum by agar diffusion method. The peptide fraction also exhibited broad antifungal spectrum against various pathogenic fungi. The minimum inhibitory concentration values for active extracts ranged between 125 ${\mu}g$/mL and 1000 ${\mu}g$/mL.

• Korean Journal of Pharmacognosy
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• v.47 no.1
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• pp.43-48
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• 2016

The aim of the study was performed to examine the anticariogenic potential of purified bee venom (Apis mellifera L., PBV) collected using bee venom collector from cariogenic bacteria, Streptococcus mutans, Streptococcus sanguis, Porphyromonas gingivalis, and Fusobacterium nucleatum. The anticariogenic effect of purified bee venom was evaluated by agar well diffusion method, minimum inhibitory concentraion (MIC), minimum bactericidal concentration (MBC), and postantibiotic effect (PAE). The human lower gingiva epithelial cell cytotoxicity of purified bee venom was also evaluated. Purified bee venom exhibited significant inhibition of bacterial growth of S. mutans, S. sanguis, P. gingivalis, and F. nucleatum with MIC value of 0.68, 0.85, 3.49, and $2.79{\mu}g/ml$, respectively. The MBC value of purified bee venom against S. mutans, S. sanguis, P. gingivalis, and F. nucleatum was 1.34, 1.67, 8.5, and $6.8{\mu}g/ml$. Furthermore, the results of PAE values against S. mutans, S. sanguis, P. gingivalis, and F. nucleatum showed the bacterial effect with 3.3, 3.45, 2.0, and 2.0. The concentration below 1 mg/ml of purified bee venom had no cytotoxicity in the human lower gingiva epithelial cell. These results suggested that purified bee venom have great potenial as anticariogenic agents.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.103-108
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• 2016

Salmonellosis is a major bacterial zoonosis that causes self-limited enteritis in animals and foodborne disease and typhoid fever in humans. Recently, multi-drug-resistant strains of Salmonella spp. have increased and caused more serious problems in public health. The present study investigated the antibacterial effects of egg-white lysozyme (EWL) against Salmonella (S.) Typhimurium and the therapeutic effects of EWL for murine salmonellosis. Evaluation of the antibacterial effects of EWL against S. Typhimurium revealed a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EWL of 6.25 and $300{\mu}g/mL$, respectively. In the bacterial growth inhibition test, EWL at 300 (p < 0.05) and $600{\mu}g/mL$ (p < 0.01) significantly inhibited the growth of S. Typhimurium at 4 h post-incubation. EWL administration at MIC (LYS-1), MBC (LYS-2) and $2{\times}MBC$ (LYS-3) for 14 days resulted in mortality of mice infected with S. Typhimurium of 70, 40 and 10%, respectively, while that of control mice (CON) was 90%. Counts of S. Typhimurium in murine spleens were significantly lower in LYS-2 and LYS-3 than CON (p < 0.05). The results of this study indicate that EWL has the potential for treatment of ICR mice infected with S. Typhimurium.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.506-512
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• 2009

The antimicrobial activity of water and ethanol extracts from 30 species of algae was measured using the agar diffusion method and minimum inhibitory concentration (MIC) test. In agar diffusion method, the 95% ethanol extracts from 12 of the algae showed growth inhibition against the tested microorganisms. In particular, Ishige okamurai, Ecklonia stolonifera, Sargassum siliquastrum, Sargassum thunbergii, Colpomenia bullosa, and Ecklonia cava had strong antibacterial activities against Gram-positive bacteria at 4 mg/mL. In the results of the MIC test, S. siliquastrum showed the most antimicrobial activity, where its MIC values ranged from 0.005 to 0.0075% against Listeria monocytogenes, Clostridium perfringens, and Basillus subtilis. In the thermal stability test, for the ethanol extracts of I. okamurai, E. cava, S. siliquastrum, S. thunbergii, and C. bullosa, the extracts proved to maintain high antimicrobial activities when they were treated at $121^{\circ}C$ for 15 min. In the pH stability test, the antimicrobial activity of the S. siliquastrum ethanol extract was stable from pH 2 to 10, whereas the activity of the other species ethanol extracts were weakened under pH 10 against several microbes.

• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.212-218
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• 2005

Most of cosmetics are emulsion products that contain the source of nutrition vegetable oil, mineral oil, natural extract and carbohydrate etc. There are many possibilities to be contaminated by microbials. We investigated the effect of antimicrobial and minimum inhibitory concentration(MIC) with thiamine dilauryl sulfate(TDS), which was prepared to use cosmetic lotion formulation. Staphylococcus aureus(S. aureus) and Escherichia col(E. coli) were used as test organism. MIC value of TDS was determined aganist microorganism for the growth inhibition by concentration of TDS. From the MIC results, antimicrobial effect of TDS was generally more effective to gram positive than gram negative. Antimicrobial effect with pH value against some microorganism appeared in the following order : pH 5 > pH 6 > pH 7. It showed strong antimicrobial activities against S. aureus, and weak antimicrobial activities against E. coli. If it was possible to determine the formulations with TDS, it would be effective to reduce the artificial preservatives.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.45-51
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• 2000

Photobacterium phosphoreum was used for the study of bioluminescence response to toxic substances including phenol, As2O3, SoO2, and CrO3 in view of developing monitoring system. measurement of inhibition of bioluminescence in P. phosphoreum has been proposed as a sensitive and raped procedure to monitor toxic substances. The concentration of toxic substance causing 50% light reduction(EC50) in bioluminescence intensity was determined with free and immobilized P. phosphoreum, The minimum inhibitory concentrations (MICs) for bioluminescence emission were found to be 400ppm for As2O3, 800ppm for phenol, 60ppm for SeO2 and 60ppm for CrO3 , respectively. The linear correlation between Gamma value and the concentration of toxic substances was obtained and EC50 wa calculated from the linear correlation. The free cells were shown to be more sensitive to toxic substances than cells immobilized on Sr-alginate and Ca-alginate. However, the linear regression curves were derived from the Sr-alginate immobilized cells indicating the immobilization method in s useful tool for monitoring of toxic substances under the more stable condition of bioluminescence.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.75-81
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• 2009

This study was carried out to assess the antilisterial potential of ethyl acetate (EtOAc) extract of a marine isolate of Aspergillus sp. The in vitro antilisterial efficacy of ethyl acetate extract was examined using disc diffusion, minimum inhibitory concentration (MIC) determination, cell viable count and scanning electron microscopic (SEM) methods against the employed strains of Listeria monocytogenus. The ethyl acetate extract ($300{\mu}g\;disc^{-1}$) exhibited a promising antilisterial effect as diameters of inhibition zones against L. monocytogenes ATCC 19111, 19116, 19118, 19166 and 15313, which were found in the range of 11-17 mm along with their MIC values ranging from 125 to $1000{\mu}g\;ml^{-1}$ respectively. Also the EtOAc extract had strong detrimental effect on the viable count of the tested L. monocytogens ATCC 19166. Furthermore, scanning electron microscopic (SEM) study demonstrated potential detrimental effect of ethyl acetate extract on the morphology of L. monocytogenes ATCC 19116 at the used MIC concentration. These findings strongly support the role of ethyl acetate extract of a marine isolate of Aspergillus sp. as an antiliterial potential.