• The Korean Journal of Mycology
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• v.21 no.3
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• pp.188-194
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• 1993

Anastomosis types and hyphal interactions in culture among different location and field isolates of Rhizoctonia solani AG-1(IA), R. oryzae and R. oryzae-sativae were examined. In the pairings of R. solani AG-1(IA) isolates, cytoplasmic fusion only occurred in the self-anastomoses, and non-cytoplasmic fusion occurred in the other combinations. In the pairings of R. oryzae isolates, cytoplasmic fusion occurred in six combinations between different location isolates and in two combinations between different field isolates from the same locations as well as in the self-anastomoses. In that case, four isolates of the fungus reciprocally made the cytoplasmic fusion. In the pairings of R. oryzae-sativae isolates, only non-cytoplasmic fusion occurred among the different location and field isolates, in which cytoplasmic fusion also occurred in the self-anastomoses. When non-cytoplasmic fusion isolates(NCFIs) of R. solani AG-1(IA) were opposed on PDA, a killing zone developed between the NCFls paired after incubation. The killing zone also developed between the NCFls of R. oryzae paired. No killing zone developed between the cytoplasmic fusion isolates(CFIs) of R. oryzae, in which mycelia of the CFIs intermingled with each other without formation of any demarcation line. An entangled zone instead of the killing zone developed between the NCFIs of R. oryzae-sativae.

• Journal of Food Hygiene and Safety
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• v.18 no.4
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• pp.183-188
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• 2003

Bactericidal effect of $Green-Zone^{(TM)}$ was observed, when Staphylococcus aureus, E. coli O157:H7, Salmonella typhimurium, S. enteritidis, Listeria monocytogenes, the causative bacteria of food poisoning, Vibrio parahaemolyticus, and Shigella sonnei were treated with the diluted solution of $Green-Zone^{(TM)}$(33.3%~4.1%) for 30min at $20^{\circ}C$. All the bacteria were killed in 30 sec, when 33.3%-diluted $Green-Zone^{(TM)}$ was applied, except for S. aureus. Coronavirus, the same virus with SARS virus taxonomically, was also lilled with the 20%-diluted $Green-Zone^{(TM)}$. Canine parvovirus and Canine distermper virus were also killed even in the organic matter and hard water when treated with $Green-Zone^{(TM)}$. When applied to food such as raw fish, chilled meat, vegetables, $Green-Zone^{(TM)}$ could also decrease the number of microorganism, expecially for E. Coli. From these results, $Green-Zone^{(TM)}$ is thought to be effective for killing virus and bacteria, and also was proved to be safe when applied directrly to food.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2441-2445
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• 2013

Chitosan non-woven fabrics were acetylated to improve their antimicrobial properties. The active chlorine content, antimicrobial properties, storage stability, and surface properties of acetylated chitosan non-woven fabrics were investigated. The active chlorine content of the fabrics increased upon reduction of the degree of the acetylation or increase in sodium hypochlorite concentration. Acetylated chitosan non-woven fabrics showed powerful antimicrobial activity by efficiently killing Escherichia coli and forming a growth inhibition zone for Staphylococcus aureus. Furthermore, scanning electron microscopy observations demonstrated that the acetylated chitosan non-woven fabrics were not damaged in sodium hypochlorite solution.

• Korean journal of food and cookery science
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• v.31 no.5
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• pp.515-523
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• 2015

In the study reported here, the antimicrobial and antioxidant activities of the ethanol leaf extract of Dendropanax morbiferus Lev. from Jeju Island was investigated. Of the 14 strains of 12 species of microorganisms tested, the extract exhibited antimicrobial activity observed against seven Gram-positive bacteria of four species, but not against six Gram-negative bacteria and a yeast strain. Using the disc diffusion method, the diameter of the inhibition zone increased with application of the extract with every strain and the highest growth inhibition was exhibited with Staphylococcus aureus KCTC 1916 at 5 mg/ml. The minimal inhibitory concentration of the extract (MIC) by turbidity was 2.5 mg/ml against Bacillus cereus KACC 12672 and 15 mg/ml when with Enterococcus faecalis KCTC 3206. The minimum bacterial concentration (MBC) values defined as being $${\geq_-}99.9%$$ reduction in viable cells against the tested strains was higher than the MIC values. Time killing curves using the optimum MIC were performed on seven strains incubated for 48 hr. The growth of B. cereus KACC 12672 was detected after 12 hr and no significant growth was found in the others strains after 48 hr (p<0.05). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity of the ethanol leaf extract was similar to that of butylated hydroxyanisole (BHA) at the same concentration. These results indicate that leaf extract of D. morbiferus Lev. can be utilized as a natural preservative and an antioxidant.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1781-1786
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• 2011

This study was conducted to investigate the cause of microbiological contamination in yogurt and evaluate the effect of physicochemical treatment on the growth inhibition of Hanseniaspora uvarum isolated from yogurt. The yeast strain Hanseniaspora uvarum Y1 was subjected to heat and pH treatments. H. uvarum Y1 was killed at $70^{\circ}C$ and $80^{\circ}C$ after 15 min and survived in a wide pH range from pH 2 to 9. However, it did not survive under pH 1 and over pH 10. In a disk diffusion susceptibility test on H. uvarum Y1, a clear zone (5 mm) of growth inhibition was observed upon treatment with electrolyzed water. The effect of ozone gas on the growth of H. uvarum Y1 was evaluated by viable cell count. Initial cell numbers of $10^2$ and $10^3$ CFU/mL of H. uvarum Y1 were completely killed by treatment for 10 and 30 min, respectively. H. uvarum Y1 was also sterilized by microwave treatment for 1 min. When treated with gamma-irradiation, the rate of killing of H. uvarum Y1 was proportional to the irradiation dose. and complete killing occurred at a dose of 50 kGy.