• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.32-37
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• 2000

Silver-alginate (Ag-alginate) was prepared with Na-alginate extracted from marine brown algae. The antibacterial effect of Ag-alginate against Staphylococcus aureus and Escherichia coli was carried out by measuring optical density of liquid culture at 600 nm. The cell growth of S. aureus and E. coli was very active at pH 7, and was inhibited by adding Ag-alginate with more than $0.006 wt.{\%}$ of stiver content. The cell growth of S. aureus .and E. coli was also influenced by the characteristics of counter Jon of silver. The cell growth of S. aureus was less inhibitory than E. coli at the same concentration of Ag-a1ginate.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.259-265
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• 2001

Staphylococal infection still remains to be one of the most serious infections, having various complications in the clinical use of indwelling polymeric medical devices. However, there are a few promising systems showing a high antibacterial effect without causing any demage of polymer backbone under biological environments such as blood or body fluid. In order to resolve this problem, we have designed a new antibiotic releasing system via a hydrolysis mechanism. The surface of biomedical polyurethane (PU) was modified by using 1,6-diisocyanatohexane (HMDI) to immobilize the rifampicon. Also, the immobilized rifampicin was designed to be released by a selective cleavage of the unstable carbamate linkage that exists on the rifampicin-immobilized polyurethane (PHR). The immobilization of rifampicin on the surface of polyurethane was confirmed by the disappearance of the characteristics IR absorbance peak of the isocyanate (-NCO) group at $2,267\;cm^{-1}$. The PHR showed a continuous rifampicin release profile under an aqueous environment of 10 mM of PBS (phosphate-buffered saline) for ove 6 days. The rifampicin molecules, which are released from PHR under an optimal bacterial infection environment, had a higher antibacterial activity against both S. aureus and S. epidermidis than rifampicin-incorporated polyurethane (RIP). In addition, the PHR maintained a stable antibacterial effect under a blood-mimic aqueous environment such as bovine calf serum.

• The Korean Journal of Mycology
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• v.13 no.2
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• pp.89-97
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• 1985

To find antibacterial strains of the soil microorganisms in Korea, they were isolated from the soil samples of different locations and screened for antibacterial activity against several standard microorganisms. An isolate among them had antibacterial activities against gram-positive and gram-negative bacteria. The examination of its morphological, biochemical, cultural and physiological characteristics according to the International Streptomyces Project methods showed that it belongs to the genus Streptomyces. This strain appears to be a novel strain when it was compared with those species of the genus which have been so far reported. The antibiotic metabolite was produced in the submerged culture of the strain. This metabolite was extracted from the culture filtrate and purified by ion-exchange column chromatography. Physico-chemical properties of the antibacterial metabolite were characterized.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.61-74
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• 2023

The global increase in multidrug-resistant (MDR) bacteria has inspired researchers to develop new strategies to overcome this problem. In this study, 23 morphologically different, soil-isolated actinomycete cultures were screened for their antibacterial ability against MDR isolates of ESKAPE pathogens. Among them, isolate BOGE18 exhibited a broad antibacterial spectrum, so it was selected and identified based on cultural, morphological, physiological, and biochemical characteristics. Chemotaxonomic analysis was also performed together with nucleotide sequencing of the 16S rRNA gene, which showed this strain to have identity with Streptomyces lienomycini. The ethyl acetate extract of the cell-free filtrate (CFF) of strain BOGE18 was evaluated for its antibacterial spectrum, and the minimum inhibitory concentration (MIC) ranged from 62.5 to 250 ㎍/ml. The recorded results from the in vitro anti-biofilm microtiter assay and confocal laser scanning microscopy (CLSM) of sub-MIC concentrations revealed a significant reduction in biofilm formation in a concentration-dependent manner. The extract also displayed significant scavenging activity, reaching 91.61 ± 4.1% and 85.06 ± 3.14% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. A promising cytotoxic ability against breast (MCF-7) and hepatocellular (HePG2) cancer cell lines was obtained from the extract with IC₅₀ values of 47.15 ± 13.10 and 122.69 ± 9.12 ㎍/ml, respectively. Moreover, based on gas chromatography-mass spectrometry (GC-MS) analysis, nine known compounds were detected in the BOGE18 extract, suggesting their contribution to the multitude of biological activities recorded in this study. Overall, Streptomyces lienomycini BOGE18-derived extract is a good candidate for use in a natural combating strategy to prevent bacterial infection, especially by MDR pathogens.

• Journal of Veterinary Science
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• v.23 no.1
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• pp.1.1-1.11
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• 2022

Background: The poor bioadhesion capacity of tilmicosin resulting in treatment failure for Staphylococcus aureus small colony variants (SASCVs) mastitis. Objectives: This study aimed to increase the bioadhesion capacity of tilmicosin for the SASCVs strain and improve the antibacterial effect of tilmicosin against cow mastitis caused by the SASCVs strain. Methods: Tilmicosin-loaded chitosan oligosaccharide (COS)-sodium carboxymethyl cellulose (CMC) composite nanogels were formulated by an electrostatic interaction between COS (positive charge) and CMC (negative charge) using sodium tripolyphosphate (TPP) (ionic crosslinkers). The formation mechanism, structural characteristics, bioadhesion, and antibacterial activity of tilmicosin composite nanogels were studied systematically. Results: The optimized formulation was comprised of 50 mg/mL (COS), 32 mg/mL (CMC), and 0.25 mg/mL (TPP). The size, encapsulation efficiency, loading capacity, polydispersity index, and zeta potential of the optimized tilmicosin composite nanogels were 357.4 ± 2.6 nm, 65.4 ± 0.4%, 21.9 ± 0.4%, 0.11 ± 0.01, and -37.1 ± 0.4 mV, respectively; the sedimentation rate was one. Scanning electron microscopy showed that tilmicosin might be incorporated in nano-sized crosslinked polymeric networks. Moreover, adhesive studies suggested that tilmicosin composite nanogels could enhance the bioadhesion capacity of tilmicosin for the SASCVs strain. The inhibition zone of native tilmicosin, tilmicosin standard, and tilmicosin composite nanogels were 2.13 ± 0.07, 3.35 ± 0.11, and 1.46 ± 0.04 cm, respectively. The minimum inhibitory concentration of native tilmicosin, tilmicosin standard, and tilmicosin composite nanogels against the SASCVs strain were 2, 1, and 1 ㎍/mL, respectively. The in vitro time-killing curves showed that the tilmicosin composite nanogels increased the antibacterial activity against the SASCVs strain. Conclusions: This study provides a potential strategy for developing tilmicosin composite nanogels to treat cow mastitis caused by the SASCVs strain.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.552-558
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• 2021

Traditional foods are manufactured according to the characteristics of each region for the nations of the world. Korea has mainly farmed, and seasonings have developed around rice and vegetables. In fermented foods, lactic acid bacteria such as Lactobacillus sp. and Pediococcus sp. and Bacillus sp. were isolated and identified from fermented foods. In this study, lactic acid bacteria were isolated and identified from commercially available traditional Korean fermented foods, and candidate strains were selected through antibacterial activity tests on human and fish disease bacteria. Thereafter, the final strain was selected by examining the resistance to simulated gastric and intestinal fluids, and hemolysis. The three (M1, K1, C13) final selected latic acid bacteria were miced with prebiotics and the antibacterial activity of synbiotics was evaluated. As for the fist antibacterial activity result, C13 showed high antibacterial acitivity in human diseases and fish diseases. Then, M1, K1 and C13, which did not produce β-haemolysis and were resistant to simulated gastric and intestinal fluids, were subjected to the second antibacterial activity of synbiotics. When the three prebiotics (FOS, GOS, Inulin) and probiotics (M1, K1, C13) were mixed, the antibacterial activity was increased or inhibited. Based on the 16S rRNA gene sequencing results, K1 and M1 were analyzed as Bacillus tequiensis 99.72%, Bacillus subtilis 99.65%, Bacillus inaquosorum 99.72%, Bacillus cabrialesii 99.72%, Bacillus stercoris 99.58%, Bacillus spizizenii 99.58%, Bacillus halotolerans 99.58%, and Bacillus mojavensis 99.51%. And C13 was analyzed as Bacillus velezensis 99.71%, Bacillus nematocida 99.36%, Bacillus amyloliquefaciens 99.44%, Bacillus atrophaeus 99.22%, and Bacillus nakamurai 99.44%.

• Korean journal of food and cookery science
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• v.27 no.3
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• pp.21-28
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• 2011

In this study, we analyzed flower tea activity against oral bacteria. Lagerstroemia indica, Paeonia suffruticosa and Hemerocallis fulva showed high extract yields. Bellis perennis, Punica granatum and Cercis chinensis showed the high rates of yield by ethanol extraction. Extract yield seemed to be related to the characteristics of the specimens rather than to the solvent. Streptococcus mutans, Streptococcus obrinus, Porphyromonas gingivalis and Prevotella intermedia were used to investigate extracts activity against bacteria; the former two cause dental caries and the latter two cause halitosis. Cornus officinalis, L. indica, P. granatum and P.s uffruticosa showed high antibacterial activities against S. mutans. In specimens extracted with ethanol, P. suffruticosa, Camellia sinensis, Camellia japonica L. and Rosa hybrida showed high antibacterial activities. L. indica, P. granatum and C. officinalis showed high antibacterial activities against S. sobrinus. C. officinalis, P. granatum, L. indica and P. suffruticosa showed high activities for specimens extracted with ethanol. The results show that the warm extracts of C. officinalis, L. indica and P. granatum may be effective to prevent dental caries. In particular, the ethanol-based extracts of C. officinalis, P. suffruticosa and C. sinensis were effective to prevent dental caries and thus may be highly marketable. Chrysanthemum zawadskii, R. hybrida, P. granatum, C. japonica L. and Zinnia elegans showed high antibacterial activity against P.gingivalis. R. hybrida showed the highest ethanol extract activity, followed by P. suffruticosa, P. granatum, C. japonica L. and L. indica. R. hybrida, P. granatum, C. morifolium and C. japonica showed high activity against Pr.intermedia in the order named. C. zawadskii, P. granatum, L. indica, C. japonica and A. princeps showed high ethanol extract activity. Thus, the warm extracts of R. hybrida, P. granatum and C. japonica may be helpful to reduce halitosis. In addition, the ethanol-based extracts of P. granatum, C. japonica and L. indica are expected to be highly marketable as mouthwashes.

• YAKHAK HOEJI
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• v.44 no.1
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• pp.36-40
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• 2000

The photodegradation of pefloxacin, photolabile fluoroquinolone antibacterial agent, was studied. In the presence of $N_2$, photodegradation of pefloxacin was suppressed. The singlet oxygen and free radical generated in the reaction media proceeded photochemical reaction. The photodegradation of peflxacin was sensitized by benzophenone, a triplet state sensitizer.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2002.10a
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• pp.98-98
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• 2002

No Abstract, See Full Text

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.63-65
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• 2008

The functional non-woven fabrics have been applied in various industry fields, such as clothing, hygiene, environment, medical and so forth. The functional non-woven fabrics were manufactured by meltblown and finishing processes. These functional non-woven fabrics were made of 2,000ppm nano-silver resin composite and polypropylene resin. Silver is one of the most universal antimicrobial substances. Nano-technology enables us to expand the surface area of silver particles markedly. Nano-silver particles were successfully produced less than 10nm in size. The functional non-woven fabrics including nano-silver particles showed excellent antibacterial activities against Staphylococcus aureus(ATCC 6538) and Klebsieila pneumoniae (ATCC 4352). From the results, nano-silver particels probably will be available as a good and safe antibiotic alternative.