• Journal of Life Science
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• v.18 no.2
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• pp.287-290
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• 2008

In order to obtain yeast cells producing a bacteriocin, Subpeptin JM4-A or Subpeptin JM4-B, the 48 bp oligonucleotides corresponding to Subpeptin JM4-A and Subpeptin JM4-B genes including codon for start and stop were chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Escherichia coli and Pseudonomas aeruginosa. This result indicates that yeast cells producing Subpeptin JM4-A or Subpeptin JM4-B possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative E. coli and P. aeruginosa cells. The recombinant yeast strains constructed in this study can be applied in the food preservative or. animal foodfeed.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.276-284
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• 2008

A lactic acid bacterium having antifungal activity was isolated from kimchi. It was identified as Lactobacillus plantarum based on its morphological and biochemical properties, and 16S rRNA sequence, and designated as Lb. plantarum AF1. This isolate inhibited the growth of Aspergillus flavus ATCC 22546, A. fumigatus ATCC 96918, A. petrakii PF-1, A. ochraceus PF-2, A. nidulans PF-3, Epicoccum nigrum KF-1, and Cladosporium gossypiicola KF-2 under a dual culture overlay assay. Also, the antimicrobial activity was found to be active against various species of Gram-positive and Gram-negative bacteria. The antifungal activity was found to be stable after heat ($121^{\circ}C$, 15 min) and proteolytic enzyme treatment, but it was unstable over pH 5.0. The antifungal compound(s) was estimated to have a low molecular mass (below 3,000 Da).

• Journal of Conservation Science
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• v.23
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• pp.81-93
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• 2008

The analysis of ancient DNA (aDNA) in paleogenetics has become an increasingly important subject of archaeological, anthropological, biological as well as public interest. In this study, paleogenetic analyses were carried out on the human skeletal remains from a historical cemetery site in Myeongam-ri, Asan, Korea. Archaeological records show that this particular location had been used as a habitation or mortuary site as early as the Bronze Age and up until the Joseon Dynasty. Human remains of twenty individuals out of forty-nine tombs from the Goryeo to Joseon Dynasty were selected for the analysis of this study. In order to identify the genealogy of the population and traditional burial pattern of the cemetery, we conducted comparative analyses of the hyper variable regions (HVRs) in mitochondrial DNA (mtDNA) of each sample. A number of cautious steps were taken at all experimental stages in order to avoid erroneous recombination by the segmental and modern contaminations derived from the researchers. We sequenced segmental amplicons of HVRs andassigned relevant haplogroups according to the sequence polymorphism on the basis of the known mtDNA database. The result shows that diverse haplogroups were unexpectedly present in the small population group of the Myeongam-ri site. This diversity appears to be related to the geographical conditions and archaeological properties of the Myeongam-ri site.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.101-105
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• 2008

In order to obtain yeast cells producing a bacteriocin OR-7, the 180 bp polynucleotide corresponding to the OR-7 gene including codons for start and stop was chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Campylobacter jeuni, Escherichia coli and Pseudomonas aeruginosa. This result indicates that yeast cells producing OR-7 possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative C. jejuni, E. coli and P. aeruginosa cells. The recombinant yeast strain constructed in this study can be applied in the food preservative or animal feed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1773-1778
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• 2009

Guava (Psidium guajava L.) contains high amount of vitamins and minerals, and its leaves have been reported to be very effective on reducing blood pressure. In this study, antimicrobial characteristics of extracts from four different parts of guava (fruit, branch, leaf, and seed) with four different solvents (methanol, ethanol, acetone, and water) were evaluated. Four targeted food-borne microorganisms were selected; two Gram negatives (Escherichia coli O157:H7 and Salmonella Typhimurium) and two Gram positives (Staphylococcus aureus and Listeria monocytogenes). By the paper disc method, guava extracts showed stronger clear hollow zone against Gram positive bacteria than Gram negatives in nutrient broth agar plate. Especially, extracts of branches and leaves showed significant antibacterial activity. Guava extracts also showed significant inhibition activity on the growth of Gram positive food-borne bacteria in nutrient broth. For example, S. aureus did not grow at all at 200 ppm of acetone extracts of guava branch and leaf. In the case of L. monocytogenes, the same concentration of acetone extracts of guava branch and leaf inhibited the growth 33.5% and 55.4%, respectively, at 32 hrs of incubation time. The results indicated that extracts of guava branch and leaf showed significant antibacterial activities against food-borne Gram positive microorganisms, and that guava branches, the byproducts of guava, might be a valuable resource for antibacterial materials.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.301-308
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• 1987

The results of experiment to find out the optimum pasteurization condition by heating from $50^{\circ}C$ to $70^{\circ}C$ at intervals of $5^{\circ}C$ and to review chemical composition, microbiological aspects and keeping quality were summarized as follows: 1. The milk sample pasteurized at $50-70^{\circ}C$ showed the decreased pH value from 6.55 to 6.42 while the contents of protein, fat, lactose and ash did not have significant changes. 2. Non-casein nitrogen and filterable nitrogen decreased while casein nitrogen and non protein nitrogen increased as the heat treatment increased. 3. The content of calcium and vitamin C decreased and artificial digestibility for the pasteruized milk increased from 14.07% to 20.00% by the heat treatment. 4. Milk pasteurized at $65^{\circ}C$ had viable bacteria counts $1.3{\times}10^4/m{\ell}$, coliforms negative, psychrotrophic bacteria $9.5{\times}10^2/m{\ell}$ and 99.0% pasteurization effect. 5. Milk pasteurized at $65^{\circ}C$ did not show significant changes in chemical composition and microbiological aspects at $4^{\circ}C$ in refrigerator.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.211-215
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• 2018

The aim of this study was to preserve the corticospinal tract during surgery and assess more accurately the motor performance in brain tumor patients around the motor cortex. TceMEP is not entirely reliable, even though there has been no change in waveforms due to a mixture of false positive and false negative signals. For a more detailed examination, DCS was employed to selectively stimulate the motor cortex. In both cases, the indications could find the region to which the cortex was responsible, and constantly check and examine the changes in amplitude, thereby preserving the motor pathway and performing surgery. On the other hand, patients who did not implement the DCS but did implement the TceMEP experienced a decrease in their postoperative motor performance. DCS is a very useful examination and it is a method that can reduce the post-surgery disorder that may occur in patients with the TceMEP in brain tumor surgery.

• Journal of Life Science
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• v.20 no.6
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• pp.934-939
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• 2010

We have previously reported recombinant productions of bacteriocins using yeast expression plasmid pAUR123, which contains the alcohol dehydrogenase (ADH) promoter, in Saccharomyces cerevisiae cells and their antibacterial activities. In order to improve the antibacterial activities of bacteriocidal yeast cells, a strong glyceraldehyde phosphate dehydrogenase (GPD) promoter gene of S. cerevisiae was amplified and inserted upstream into bacteriocin genes such as the OR-7, Subpeptin JM4-A or JM4-B gene in the corresponding recombinant yeast plasmid. Yeast cells transformed by the recombinant plasmid containing the GPD promoter represented higher antibacterial activities against both Gram positive B. subtilis and Gram negative E. coli cells compared to those transformed by the corresponding recombinant plasmid containing the ADH promoter. Thus, yeast cells harboring the recombinant plasmid containing the GPD promoter constructed in this study could be applied in the food preservative or animal feed industries.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.3
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• pp.256-262
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• 2017

Essential oil from herb is known to exert pharmacological effects on the human body. In this study we investigated the antibacterial activity of 4 essential oils (teetree, rosemary, melisa, and lavender), as well as the blended mixture oil of teetree, rosemary, and melisa (TRM) on three bacteria, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Antibacterial analysis was performed using the standard disk diffusion method, and minimum inhibition concentration was determined by the broth microdilution method with different concentrations of essential oils (0.5, 1, 2 and 3 mg/mL). After incubation at $37^{\circ}C$ for 24 h, the antibacterial activity was assessed by measuring the zone of growth inhibition surrounding the disks. Herb oil with the inhibition zones showed varied values ranging from6 to 25 mm. However, the components of herb oil of TRM are as highly active as the teetree oil against pathogens, generating large inhibition zones for both gram negative and positive bacteria (13~22 mm and 8 mm inhibition zones). In the analysis for MIC, TRM showed growth-inhibitory effects at 0.0625% for S. aureus and E. coli, and 1.25% for P. aeruginosa. This result demonstrated that the anti-microbial activity of TRM was greater than a single herb oil, including oxacillin, rosemary, and teetrea. As a single herb oil, both rosemary and teetrea also had an anti-microbial effect by itself, and we can expect that the blended oil mixture may exert a synergistic effect against multidrug resistant bacteria, suggesting its future application in natural preservative agents for health food and cosmetics.

• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.154-161
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• 2010

The aim of this study was to investigate antibacterial activities of essential oil from C. morifolium against four Grampositive bacteria and six Gram-negative bacteria. The antibacterial activity of the oils was determined by agar-well diffusion assay, minimum inhibitory concentration(MIC), and minimum bactericidal concentration(MBC). Essential oil of C. morifolium had a large inhibition zones especially against Salmonella enterica(21 mm) and Bacillus cereus(19 mm). Essential oil of C. morifolium generally showed higher antibacterial activity against Gram-positive bacteria than Gram-negative bacteria. MIC of essential oil from C. morifolium was 5 ${\mu}g/m{\ell}$ against ten food-borne pathogens. MBC values were determined to be from 5 to 20 ${\mu}g/m{\ell}$ against eight bacteria except Salmonella choleraesuis and Listeria monocytogenes. Therefore, the essential oil of C. morifolium and its components have a potent antibacterial activity against food-borne pathogens, and is expected to be used as a novel food preservative.