• Proceedings of the Korean Environmental Health Society Conference
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• 2005.11a
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• pp.110-114
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• 2005

인공적으로 디젤류에 오염시킨 5kg의 토양이 충전된 두 개의 실험 column을 이용해서 외부 온도변화 효과를 최소화하기 위해서 $25^{\circ}C{\pm}2.5$로 유지시켰으며, 유량속도도 10ml/min로 일정하게 유지시켰다. 또한 수분은 활동범위 능력의 $60{\sim}80%$에서 유지시켰다. 따라서 연속식과 간헐 주입식 모드를 운전비용의 감소 및 효율의 향상 측면에서 모드의 평가를 위한 방법으로 이용기간 동안 총세균 수, 유류분해균 수의 변화, 탈수소효소 활성도의 변화 추이 분석을 하였다. 두 venting 모드별로 본 총 종속영양균 수와 유류분해균 수는 모두 대등한 성장률을 보였으며, 반응일 수에 따라 비교된 탈수소효소 활성도 반응 90일 동안 비슷한 활성을 유지 했다.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.129-134
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• 2003

The purpose of the present study was to screen the effective of lactic acid bacteria (LAB) as probiotics, which are able to protect aquacultural fish pathogenic bacteria, and investigate their characterization. Twenty strains of lactic acid bacteria were isolated from fish intestine, fermented fish foods and kimchis. These bacteria were screened for antagonistic activity against fish pathogenic bacteria. Seven tested LAB strains were able to inhibit the fish pathogenic bacteria, including Vibrio anguillarum, Edwardsiella tarda, and Streptococcus sp.. Of the probiotic candidates, BK19 strain isolated from fermented pollack viscera indicated the largest inhibition activity. Moreover, this strain showed a resistance over low pH and antibiotic agents. Therefore this probiotic candidate BK19 was finally selected and identified as a probiotic strain. This particular probiotic bacteria was identified as Lactobacillus sakei BK19 by biochemical characteristics and 165 rRNA PCR amplification.

• Journal of Applied Biological Chemistry
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• v.65 no.2
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• pp.101-105
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• 2022

Quercetin is a major flavonoid in onion and known to antimicrobial activity against several pathogenic bacteria. However, the antibacterial activity of quercetin had not been evaluated against plant pathogenic Xanthomonas campestris and Erwinia carotovora. In here, quercetin and the solvent extracts of onion were investigated their antibacterial activity. Quercetin showed a selective inhibitory activity against X. campestris, and the minimal inhibition concentration (MIC) and minimal bactericidal concentration of quercetin were 15.6 and 20.0 ㎍ mL^-1 respectively. Otherwise, it showed no inhibitory activity against E. carotovora, and no the additive and the synergistic effects with streptomycin on X. campestris. And the EtOAc extract from the peel of onion that contained quercetin showed 2-fold lower MIC (500 ㎍ mL^-1) than the EtOH extract, thus EtOAc was suggested as the extraction solvent for quercetin from onion peel.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.119-125
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• 2009

To understand the ecological function of heterotrophic bacterial community in water column of large freshwater lakes in the permafrost zone, we investigated the structure and function of bacterial community in Lake Khuvsgul, Mongolia. Species composition of overall bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments, and bacteria that can be cultured at 10oC were isolated and characterized. Based on the depth profile of environmental parameters, thermocline and chemocline were recognized at the 5~10 m zone of the water column. The stratified DGGE profile indicated that the discontinuity of water properties might influence the structure of bacterial community: band profiles in the 0~5 m zone were diverse with large change by depth, but the profile was relatively stable at the $\geq$10 m zone, with predominance of the band identified as Acidovorax facilis. Bacterial cultures were screened for protease, cellulase, amylase and lipase activity, and 23 isolates were selected for high activity of the hydrolytic enzymes. The isolates were identified based on their 16S rRNA gene sequences. In the surface water (zero meter depth), Acidovorax defluvii and Sphingobacterium faecium with high cellulase activity were present. Flavobacterium succinicans, Mycoplana bullata and A. facilis were stably predominant isolates at 2 m, 5 m, and $\geq$10 m depths, respectively. F. succinicans isolates showed high protease activity while M. bullata isolates showed moderate levels of protease and celluase activity. A. facilis isolates showed either cellulase or lipase activity, exclusively to each other. According to the profile of growth rates of the isolates in the temperature range of $0\sim42^{\circ}C$, the surface-zone (0~5 m) isolates were facultative psychrophiles while isolates from $\geq$10 m depth were typical mesophiles. This stratification is believed to be due to stratified availability of organic materials to the bacterial decomposers. In the water column below the chemoline, the environment is extremely oligotrophic so that the trait of rapid growth in low temperature might not be demanded by deep-lake decomposers. The stratified distribution of community composition and decomposer activity in Lake Khuvsgul implies that ecological functions of bacterial community in lakes of cold region are sharply divided by water column stratification.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.353-360
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• 2003

Immunodepression can be required for entomopathogenic bacteria to induce their potent pathogenicities to the target insects. Here, we raise a hypothesis that the capacity of a pathogenic bacterium to induce the target insect immunodepression has positive relationship with the degree of pathogenicity. X. nematophilus had 1,200 times as potent as another entomopathogenic bacterium, Staphylococcus gallinarum against the fifth instar larvae of silkworm, Bombyx mori, when they were Injected into the hemocoel. Although both bacteria had significant cytotokic effect on the hemocytes of B. mori, X. nematophilus gave faster and greater cytotoxicity than did S. gallinarum. In cellular immune reactions, B. mori could form 20 hemocyte nodules against the bacterial injection with 5${\times}$10$\^$5/ cells. The number of the hemocyte nodules was significantly depressed when live X. nematophilus was inject-ed, but not in S. gallinarum. Activation of prophenoloxidase (proPO) was depressed in the bacterial injection. The depression of PO activation was significantly greater in X. nematophilus infection than in S. gallinarum injection. Lysozyme activity was induced by the injection of S. gallinarum at 4 h after the treatment, but not induced in X. nematophilus at all the time. These results showed that X. nemato-philus induced greater immunodepression against B. mori and resulted in higher pathogenicity than did S. gallinarum. Therefore, this study suggests that the immunodepression induced by entomopathogenic bacteria has positive relationship with their pathogenicity.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.341-348
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• 2010

Antifungal and antibacterial activities of wood vinegars were investigated in this study in order to apply for the natural fungicides and food preservatives. The antifungal activities of wood vinegars were measured as a hyphal growth inhibition rate using four plant pathogenic, four wood rot and one mushroom pathogenic fungi. Inhibition effect on the fungi growth was explicitly observed at the concentrations higher than 0.5% of unrefined wood vinegar and higher than 1.0% of refined wood vinegar, respectively, suggesting that unrefined wood vinegars showed the higher antifungal activities than that of refined wood vinegars. The highest inhibition effect on the fungi growth was shown in Libertella betulina which is a mushroom pathogenic fungus. In addition, the wood vinegars from Pinus densiflora showed the higher antifungal activities against the plant pathogenic and wood rot fungi than that from Quercus spp.. On the other hand, the antibacterial activities of wood vinegars were determined by a paper disc method using the three gram positive and five gram negative bacteria. The unrefined wood vinegars showed a prominent effect on the suppression of bacteria growth at the concentration of 10%, while the suppression of bacteria growth was not observed in the refined wood vinegars. These results also suggest that the unrefined wood vinegars showed the higher antibacterial activities than the refined wood vinegars. The antibacterial activities of wood vinegars against gram positive bacteria were higher than those of wood vinegars against gram negative bacteria. From these results, it can be inferred that the wood vinegars has the strong antimicrobial activities and can be applied as the natural fungicides and food preservatives.

• The Korean Journal of Ecology
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• v.23 no.5
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• pp.369-375
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• 2000

Although urban soils must be well understood in order to ensure their conservation and optimum use, these intensively managed and disturbed soils have not been extensively investigated up to now. Urban soils from forest, lawn, streetside, and bare ground and under pavement in Inchon had high bulk density as a result of widespread trampling-induced soil compaction. The various urban soils including forests showed lower water content and higher temperature as compared with rural forest soil. Chemically, soils from urban areas had an unusual neutral pH and low organic matter content. Total bacterial numbers in urban soils was only 5∼50% of that in the rural forest soil. An analysis of stepwise multiple regression revealed that soil organic matter was the most important predictor variable on total bacterial number. The dehydrogenase activity of most urban soils was not significantly different from that of rural forest soil, whereas the microbial activity of soils under pavement was lower. Our investigations show that inadequate organic matter of highly compacted soils has adversely affected the abundance of microorganisms involving nutrient cycling in urban soils.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.31-37
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• 1994

For a microbiological study of composting process, screening and assay method for biopolymer degrading enzymes and microorganisms were developed and for the study of the possibility of composting in anaerobic state, distribution of sulfate reducing bacteria which plays a final role in anaerobic degradation was investigated. Substrates used for the development of assay methods for biopolymer degradation are ${\beta}-glucan$, xylan, dextran, CMC(carboxy methly cellulose), casein, and collagen. These substrates were made insoluble by a cross-linking agent and linked with dye to make chromogenic substrates. ${\beta}-glucan$ and xylan substrates could substitute congo-red method for screening of polymer degrading microorganisms without damaging the colonies. Sulfate reducing bacteria contained in the sample sludge showed preference to lactic acid, propionic acid, butyric acid and formic acid and could use acetic acid and valeric acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1317-1324
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• 2015

The objective of this study was to examine both antioxidant activities and quality characteristics of sausages made from a mixture of purple sweet potato powder and pigment. Five sausages were manufactured: F0 (control), F1 (0.15%-sodium nitrite), F2 (0.2%-purple sweet potato pigment), F3 (0.2%-purple sweet potato pigment and 5%-purple sweet potato powder), and F4 (0.2%-purple sweet potato pigment and 10%-purple sweet potato powder). Sausages were stored at $4{\pm}1^{\circ}C$ for 30 days. Total polyphenol, 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging activity, acid value, peroxide value, volatile basic nitrogen (VBN), and total bacterial cell contents were analyzed. Total polyphenol content and DPPH radical scavenging activity increased according to the amount of purple sweet potato, whereas acid value, peroxide value, and VBN decreased. Addition of 0.2% purple sweet potato pigment increased lipid oxidative stability and protein deterioration inhibitory effect compared to F0, but not to the levels of 0.15% sodium nitrite. However, F2 showed the lowest pH during storage due to the pH (2.52) of the pigment. Microorganism analysis revealed that total bacterial counts of sausage added with 0.2% purple sweet potato pigment were significantly lower (P<0.05) than that of sodium nitrite-supplemented sausage. As a result, purple sweet potato powder and pigment demonstrate antioxidative activity and lipid oxidative stability in sausages, making them suitable ingredients for manufacturing sausages.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.311-328
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• 2017

This study was carried out to investigate the changes in soil microorganisms and soil enzymes by split irrigation and organic matter application under no-tillage green house conditions. Soil bacteria and fungi abundances were higher in soybean cake fertilizer than in the soil without the soybean cake fertilizer under whole quantity irrigation. Bacteria and fungi abundances in soil increased with increasing organic fertilizer application rate. Bacteria and fungi amount in the soil increased at half division irrigation in no-treatment of soybean cake fertilizer compared with whole quantity irrigation. Actinomycete amount in the soil decreased with increasing soybean cake fertilizer with whole quantity irrigation while clearly increased in no-treatment of soybean cake fertilizer. Actinomycete amount in soil clearly increased with increasing organic fertilizer input at half division irrigation. Chitinase activity in the soil decreased in soybean cake fertilizer with increasing organic fertilizer input, while increased in no-treatment of soybean cake fertilizer. Chitinase activity in the soil increased at half division irrigation compared with whole quantity irrigation regardless of soybean cake fertilizer input. ${\beta}$-Glucosidase activity in the soil was higher in soybean cake fertilizer than in no-treatment of soybean cake fertilizer with whole quantity irrigation. ${\beta}$-Glucosidase activity in the soil increased with increasing organic fertilizer input, but decreased in above the standard level 66%. ${\beta}$-Glucosidase activity in the soil clearly increased in no-treatment of soybean cake fertilizer at half division irrigation compared with whole quantity irrigation. N-acetyl-${\beta}$-D-glucosaminidase activity was higher in soybean cake fertilizer than in no-treatment of soybean cake fertilizer with whole quantity irrigation. N-acetyl-${\beta}$-D-glucosaminidase activity in the soil increased with increasing organic fertilizer input, but decreased in above the standard level 66%. N-acetyl-${\beta}$-D-glucosaminidase activity in the soil was not significantly different at half division irrigation and whole quantity irrigation in organic fertilizer input, while increased at half division irrigation in no-treatment of soybean cake fertilizer. Acid phosphatase activity increased at standard level 66% in soybean cake fertilizer, while was not significantly different in no-treatment of soybean cake fertilizer. Spore density of Arbuscular Mycorrhizal Fungi (AMF) in the soil increased with increasing organic fertilizer input at whole quantity irrigation in no-treatment of soybean cake fertilizer, while decreased above the standard level 66% in organic fertilizer input. However, spore density of AMF in the soil was not significantly different in soybean cake fertilizer regardless of input amount of organic fertilizer. Root colonization rate of AMF in red pepper roots was not significant difference at two irrigations regardless of soybean cake input.