• Food Science of Animal Resources
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• v.36 no.3
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• pp.421-426
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• 2016

Polylactic acid (PLA) is a biodegradable and renewable polymer, which represents a valuable alternative to plastic packaging films, often associated with environmental problems. In this study, we tested the suitability of PLA as a biodegradable packaging film and assessed the antimicrobial activity of lemongrass oil (LO), incorporated into the PLA film in different concentrations. To obtain the optimal physical properties for PLA films, tensile strength, elongation at break, and water vapor permeability were measured under different preparation conditions. In addition, the antimicrobial activity of the LO contained in the PLA film against Listeria monocytogenes was investigated by disc diffusion and viable cell count. Among all concentrations tested, 2% LO was the most suitable in terms of antimicrobial activity and physical properties of the PLA film. Based on these results, we used the PLA film containing 2% LO to pack pork sausages; after 12 d of storage at 4℃, the population of inoculated L. monocytogenes in the sausage samples wrapped with the PLA film containing 2% LO was reduced by 1.47 Log CFU/g compared with the control samples. Our data indicate that PLA films containing 2% LO represent a valuable means for antimicrobial sausage packaging.

• Journal of Environmental Health Sciences
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• v.38 no.2
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• pp.142-150
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• 2012

Objectives: To estimate the multi-antibiotic resistant bacterial contaminant load discharged from livestock farms, we randomly selected livestock farms specializing in cattle, swine, and fowl and collected bacterial strains from domesticated animal feces and compost samples. Problems with resistance to antibiotics are becoming worldwide issues, and as the consumption of antibiotics appears to be excessive in Korea as well, the emergence of antibiotic resistant bacteria shows the possibility to cause potentially serious social problems. Methods: To monitor multi-antibiotic resistant bacterial constituents, aerobic bacteria and Escherichia coli were isolated from domesticated animal feces and compost. Antibiotic resistance testing was performed by the disc diffusion method using 13 different antibiotics. Results: Examining the degree of sensitivity to antibiotics of the aerobic bacteria originating from domesticated animal feces, fowl feces showed the highest distribution rate (35.5%), followed by swine feces compost (23.1%), swine feces (18.2%), cattle feces (14.9%), and cattle feces compost (8.2%). Antibiotic resistance tests of aerobic bacteria and E. coli originating from domestic animals feces resulted in 83.6% and 73.5% of each strain showing resistance to more than one antibiotic, respectively. Conclusions: These results suggest that increasing multi-antibiotic resistant bacteria in the environment has a close relation to the reckless use of antibiotics in livestock.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.278-283
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• 2014

Cecropins (Cec) are antibacterial peptides and their expression is induced in a pig intestinal parasite Ascaris suum by bacterial infection. To explore the usefulness of its activity as an antibiotic, CecP4 cDNA was prepared and cloned into the pPICZ B expression vector and followed by the integration into AOX1 locus in Pichia pastoris. The supernatants from cell culture were collected after methanol induction and concentrated for the test of antimicrobial activity. The recombinant P. patoris having CecP4 showed antimicrobial activity when tested against Staphyllococcus aureus in disc diffusion assay. We selected one of the CecP4 clones (CecP4-2) and performed further studies with it. The growth of recombinant P. pastoris was optimized using various concentration of methanol, and it was found that 2% methanol in the culture induced more antibacterial activity, compared to 1% methanol. We extended the test of antimicrobial activity by applying the concentrated supernatant of CecP4 culture to Pseudomonas aeruginosa and E. coli respectively. Recombinant CecP4 also showed antimicrobial activity against both Pseudomona and E. coli, suggesting the broad spectrum of its antimicrobial activity. After improvements for the scale-up, it will be feasible to use recombinant CecP4 for supplementation to the feed to control microbial infections in young animals, such as piglets.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.195-202
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• 2017

The objective of this study was to investigate the antioxidant and antimicrobial properties of quinoa cultivated in Korea and to compare it with imported quinoa from the USA and Peru. The highest amount of total flavonoid contents (TFC) with 20.91 mg quercetin equivalents/100 g was measured in quinoa seed extract cultivated in Korea, while the total phenolic contents (TPC) were significantly higher in quinoa from the USA (16.28 mg gallic acid equivalents/100 g). In addition, quinoa extracts cultivated in Korea displayed a superior antioxidant ability in both, ferric reducing antioxidant power and 1,1-diphenyl-2-picrylhydrazyl values. There was a high correlation between TFC and antioxidant activity and a low correlation between TPC and antioxidant activity. The antimicrobial activity of the quinoa extracts was determined using a disc diffusion assay and optical density method. In both assays, the quinoa seed extracts did not have strong antimicrobial activity against foodborne bacteria, including Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Escherichia coli, Salmonella Typhimurium, and Campylobacter jejuni.

• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.185-189
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• 2001

Essential oils of 21 herb plant samples, using spectrophotometric and paper disc agar diffusion methods under anaerobic conditions, were tested in vitro for their growth-inhibiting activities against Bifidobacterium bifidum, B. longum, Lactobacillus casei, Clostridium perfringens, and Escherichia coli. The responses varied with bacterial strains and plant oils. At 10 mg/disk, all essential oils did not inhibit beneficial intestinal bacteria, except for the oil of Alpinia officinarum and Melaleuca alternifolia against L. casei. Due to their strong growth-inhibitory activities against C. perfringens, E. coli, and L. casei, the activites of nine oils were evaluated at low concentrations. In test with C. perfringens at 1 mg/disk, the oils of Amyris balsamifera, Curcuma longa, M. alternifolia, and Trachyspermum ammi showed moderate activities. Moderate activities against E. coli were observed with the oils of M. alternifolia and T. ammi. These results may be indications of at least one of the pharmacological actions of the four herb plants.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2006.11a
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• pp.88-89
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• 2006

Fowl cholera is an infectious disease caused by .Pasteurella multocida, affecting domesticated and wild birds. It usually appears as a septicemia of sudden onset with high morbidity and mortality, but chronic conditions that characterized by localized infections often occur. 13wks broiler breeders were submitted to the Kyung-pook national university for diagnosis. Clinical signs included approximately 1% mortality, severe lameness, ruffled feathers and swollen and/or cloudy eyes. At necropsy, the outstanding lesions were seen swollen hock joint, which were suppurative or caseous exudates, inflammation of conjunctiva, severe pneumonia and epicarditis. The causative agent was isolated from the hock joint, liver, sinus and sternum of the chickens, and performed physiological and biochemical test. To identify the serotype of P. multocida, capsular serotyping was conducted by multiplex polymerase chain reaction (PCR). In the antimicrobial susceptibility test, the isolates were resistance to the aminoglycosides. In this study, we confirmed chronic fowl cholera (FC) caused by P. multocida in broiler breeders in Korea.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.57-63
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• 2013

This study compared the antimicrobial activity and total phenolic content of three Pinus plants (Pinus densiflora, P. thunbergii, P. rigida) for the first time. The antimicrobial activity of the water fraction of methanol extract of fresh leaves was stronger than that of fallen leaves at any concentrations. The water fraction of crude methanol extract from fresh leaves of P. thunbergii showed a higher growth inhibitory activity against gram-positive and gram-negative bacteria than that of P. densiflora and P. rigida. The results from the disc diffusion method followed by measurements of minimal inhibition concentration (MIC) indicate that Bacillus subtilis was the most sensitive microorganism with the lowest MIC value. The highest total phenolic content was found in fresh leaves of P. rigida and P. thunbergii. The assay showed that the fresh leaves of the three Pinus plants contained higher total phenolic content than fallen leaves of the three plants. The antimicrobial activity was related with the total phenolic content.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.187-189
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• 2013

The antimicrobial activities of emodin and its derivatives (anthraquinone, alizarin, and alizarin-3-methyliminodiacetic acid) were evaluated using a paper disc diffusion method against foodborne bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus intermedius, Salmonella typhimurium and Shigella sonnei). Emodin isolated from C. tora seeds has an antimicrobial activity against Bacillus cereus, followed by alizarin-3-methyliminodiacetic acid ($13.0{\pm}2.5mm$) and alizarin ($11.5{\pm}1.2mm$). Furthermore, emodin showed the antimicrobial activity against S. sonnei and S. typhimurium. In conclusion, C. tora seed and its active component derivatives are useful for the development of natural products on food supplemental agents and pharmaceuticals.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1322-1326
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• 2013

New antifungal agents are required to compensate for the increase in resistance to standard antifungal agents of Candida albicans, which is an important opportunistic fungal pathogen that causes minor infections in many individuals but very serious infections in those who are immune-compromised. In this study, combinations of theaflavin and epicatechin are investigated as potential antifungal agents and also to establish whether antifungal synergy exists between these two readily accessible and cost-effective polyphenols isolated from black and green tea. The results of disc diffusion assays showed stronger antibacterial activity of theaflavin:epicatechin combinations against C. albicans NCTC 3255 and NCTC 3179, than that of theaflavin alone. Minimum inhibitory concentrations (MICs) of 1,024 ${\mu}g/ml$ with theaflavin and 128-256 ${\mu}g/ml$ with theaflavin:epicatechin combinations were found. The fractional inhibitory concentration indexes were calculated, and the synergy between theaflavin and epicatechin against both isolates of C. albicans was confirmed. Theaflavin:epicatechin combinations show real potential for future use as a treatment for infections caused by C. albicans.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.37-42
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• 2000

Drug delivery system(DDS) have been actively studied for the past twenty years. Dual action agents are unique chemical entities comprised of two different types of antibacterial compounds covalently linked together in a single molecule in such a way that both components are able to exert their bactericidal properties. In spite of the advent of the antibacterial agent the sulfa agents are the most widely used antibacterial agent today. In this study, new antibacterials derivative was synthesized using glutaraldehyde such as crosslinking agent for the purpose of dual-action as DDS study. Antibacterial activity of these new synthetic derivative between their structures and activities were examined by disc diffusion method. As a result, new synthetic derivative exhibited the broad antibacterial activities against Gram(+) and Gram(-) bacilli. Especially, the antibacterial effect of new synthetic derivative against Gram negative(Esherichia. coli) was much stronger than that against Gram positive.