• Economic and Environmental Geology
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• v.47 no.4
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• pp.431-439
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• 2014

The purposes of this research were to investigate the enrichment of metal-reducing bacteria from KURT groundwater and the identification of the microbial diversity by 16S rRNA as well as to examine microbial Fe(III)/Mn(IV) reduction and to analyze morphological features of interactions between microbes and precipitates and their mineralogical composition. To cultivate metal-reducing bacteria from groundwater sampled at the KURT in S. Korea, different electron donors such as glucose, acetate, lactate, formate, pyruvate and Fe(III)-citrate as an electron accepter were added into growth media. The enriched culture was identified by 16S rRNA gene sequence analysis for the diversity of microbial species. The effect of electron donors (i.e., glucose, acetate, lactate, formate, pyruvate) and electron acceptors (i.e., akaganeite, manganese oxide) on microbial iron/manganese reduction and biomineralization were examined using the 1st enriched culture, respectively. SEM, EDX, and XRD analyses were used to determine morphological features, chemical composition of microbes and mineralogical characteristics of the iron and manganese minerals. Based on 16S rRNA gene analysis, the four species, Fusibacter, Desulfuromonas, Actinobacteria, Pseudomonas sp., from KURT groundwater were identified as anaerobic metal reducers and these microbes precipitated metals outside of cells in common. XRD and EDX analyses showed that Fe(III)-containing mineral, akaganeite (${\beta}$-FeOOH), reduced into Fe(II)/Fe(III)-containing magnetite ($Fe_3O_4$) and Mn(IV)-containing manganese oxide (${\lambda}-MnO_2$) into Mn(II)-containing rhodochrosite ($MnCO_3$) by the microbes. These results implicate that microbial metabolism and respiratory activities under anaerobic condition result in reduction and biomineralization of iron and manganese minerals. Therefore, the microbes cultivated from groundwater in KURT might play a major role to reduce various metals from highly toxic, mobile to less toxic, immobile.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.305-312
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• 2019

This study investigated the effect of diet supplementation with pine cone extracts (pine cone ethanol extract: PCEE; pine cone ethanol-hexane extract: PCEHE) on growth performance, digestive organ characteristics and intestinal microbiota of semi-broiler. Twenty two-weeks-old semi-broilers were divided into four dietary groups (n=5/group; control(-): no antibiotics and pine cone extracts; control(+): 2% antibiotics [20 g/kg basal diet]; PCEE: 2% PCEE [20 g/kg basal diet]; PCEHE: 2% PCEHE [20 g/kg basal diet]). Chicks were reared and their diets were supplemented accordingly for 16 days. Final weight, weight gain and feed intake were lowest (P<0.05) in semi-broilers whose diet was supplemented with pine cone extracts, but both PCEE and PCEHE groups showed lower (P<0.05) feed conversion ratios compared to the control(-) group. Gizzard and small intestinal weight were also lower (P<0.05) in both PCEE and PCEHE groups than in the control(-) group. Intestinal length and villus height were similar for all treatments. Furthermore, cecal microbiota was not improved by PCEE and PCEHE supplementation. These findings suggest that diet supplementation with pine cone extracts improves the feed conversion ratio and affects the digestive organ weight of semi-broilers.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.75-81
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• 2021

Recent gut microbiota studies have revealed the important roles of gut microbiota for our health. Increasing numbers of health functional foods have been developed every year. Development of functional food often includes ex- and in-vivo experiment to verify the beneficial effects of the functional food. To investigate effects of functional food on gut microbiota, animal models were often conducted. Beneficial effects of food can be evaluated based on how gut microbiota was shifted by food, which results in either increase in beneficial bacteria, decrease in potentially pathogenic bacteria or both. As animal experiments are generally time-consuming and laborious, we investigate how well in-vitro investigation of fecal microbiota may reflect dietary health benefits. Here, we tested 15 kinds of diets using two human subjects' fecal materials. Our results showed varying gut microbiota shifts according to diets, which suggested generally known beneficial diets (i.e. Kimchi, Chunggukjang) increased Lactobacillus and Bifidobacterium. Therefore, we suggest that in vitro fecal microbiota analysis could be used to evaluate beneficial effects of diets. Moreover, this method may be ideal to establish personalized diet.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.17-22
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• 2004

Scutellaria baicalensis and Phellodendron amurense, which have been used traditionally in treatment of many kinds of illness including infectious diseases, were extracted with hexane, dichloromethane, methanol and water, respectively and serially. Antimicrobial activities of the extracts were examined by disk diffusion method. Methanol extract from Scutellaria baicalensis revealed high antimicrobial activities against MRSA, Gm-bacteria and Candida albicans, dichloromethnane extract from Phellodendron amurense showed lower activity than the extract of Scutellaria baicalensis. Results suggest that methanol extract from Scutellaria baicalensis could be one of the candidates for new antimicrobial agent against the antibiotic-resistant microorganisms by further steps for the purification, determination of structure and synthesis.

• Journal of Life Science
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• v.31 no.2
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• pp.183-191
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• 2021

Euglena gracilis is a microalga of great biotechnological interest that can create high levels of bioactive compounds, such as tocopherol, paramylon, and folic acid. The objective of this study was to investigate the biological activities of extracts from E. gracilis, especially those focused on immunological activity. E. gracilis biomass was extracted with hot water (HWE) and the remaining pellet was continuously extracted with methanol (HWME). First, we examined the effect of two extracts from E. gracilis on the production of nitric oxide (NO) and the expression of pro-inflammation cytokines, including IL-1β, IL-6, and TNF-α in murine macrophage RAW 264.7 cells. HWE treatment dose-dependently increased the production of IL-1β and TNF-α. On the other hand, treatment with HWME significantly decreased the generation of NO and pro-inflammatory cytokines (IL-6 and TNF-α) in lipopolysaccharide (LPS)-stimulated macrophage cells. In addition, other biological activities of the extracts were further analyzed: α-glucosidase inhibition, protein tyrosine phosphatase (PTP1B) inhibition, tyrosinase inhibition, xanthine oxidase (XO) inhibition, and angiotensin-converting enzyme (ACE) inhibition. Analysis of these biological activities showed that HWE has more inhibitory effects than HWME against α-glucosidase, tyrosinase, and XO agents. However, the inhibition of PTP1B and ACE with HWME were higher than with HWE. Taken together, the results suggested that E. gracilis possesses various biological activities―especially immunological capabilities―through regulation of cytokine production. Therefore, E. gracilis extract may be potentially useful for food material with immune-regulating effects.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.242-249
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• 2003

Antimicrobial activity of Caesalpina sappan L. extract (CS extract) against animal husbandry disease-related bacteria was studied. The CS extracts showed a significant antimicrobial activity against Gram(+) bacteria and this antimicrobial activity was most significant against Staphylococcus epidermidis. Minimum inhibitory concentrations (MIC) of CS was in the range of 0.8∼16 mg/ml and 0.8∼10 mg/ml, in the case of MeOH extracts and EtOH extracts, respectively. In addition, the antimicrobial activity of each solvent fraction was most significant with EtOAc layer. The antimicrobial activities of CS extracts against most microbial strains were stable by either heat treatment or acid treatment, whereas those against S. aureus and Sal. typhimurium were reduced by acid treatment. The inhibitory effect of CS extracts on microbial cell growth was further examined by the addition of 0, 100, 300, and 500 ppm of CS extracts into growth medium. The growth of gram(+) bacteria, S. aureus and S. epidermidis, was inhibited for 72 hours in all ranges of CS extracts added, but the growth of gram(-) bacteria was only inhibited when at least 100 ppm of CS extracts were added. Taken together, the antimicrobial activities of CS extracts were more effective against gram(+) bacteria compared to those against gram(-) bacteria.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.243-249
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• 2001

This study was investigated to determine the antimicrobial effect of the ethanol extract of Quercus mongolica leaf on microbial growth. The ethanol extract at the concentration of $250\;\mu\textrm{g}/mL\;and\;500\;\mu\textrm{g}/mL$ inhibited the growth of gram positive and gram negative food-borne disease bacteria for 40 hours in tryptic soy broth, respectively. Antimicrobial activity of the ethanol extract from Quercus mongolica leaf was not affected by pH and heat treatment. The comparision between ethanol extract and commercially available preservatives on antimicrobial activity in food system was conducted. When the 0.1% ethanol extract of Quercus mongolica leaf was added to pine needle drink and carrot juice, antimicrobial activity was similar to those of containing 0.05% benzoic acid and 0.5% grapefruit seed extract. Also addition of 2~3% ethanol extract to the soybean paste inhibited the microbial growth up to 7 week, comparable to the inhibition of 2% ethanol. Thus, this results indicate that the ethanol extract of Quercus mongolica leaf may be useful as natural antimicrobial agents.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.438-444
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• 2002

The purpose of this study is screening of microfloras involved in hydrolysis of sea tangle (Laminaria japonica) and sea mustard ( Undaria pinnatifida), This is a part of studies on the hydrolysis of seaweed using microorganisms. General process is difficult to extract of the useful constituent parts as intercellular mucilage, storage polysaccharide and mineral from seafood. It was screening to thirty-three microflora samples as destructed of tissue in sea tangle and sea mustard to about two hundred microflora samples from mountain, rice field, dry field, sea, seaside and fish market etc. in the neighborhood of Yeosu. Sufficient results of the naked eye observation were obtained at eight microflora samples as a feces of bull, a decayed pine tree, a soil of dry field, the mud of the banks in a rice Held, the water of a ditch in a rice Held, the weed of the banks in a rice field, the water in a rice field and leaved in the air, And the value of chemical analysis of the sample is much better in comparison with control. Accordingly, the hydrolysis of seaweed using microorganisms in the inside of these microflora samples can possibility.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.64-64
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• 2018

생물전환(Bioconversion)은 천연소재의 기능성을 증대시키기 위한 방안으로 많은 연구가 진행되고 있으며 다양한 산업에서도 활용되고 있어 유용미생물을 기반 차세대 기술로 각광받고 있다. 이러한 기술의 도입은 식품은 물론 의약품 및 화장품 산업에서도 활발히 사용되고 있으며, 특히 최근 기능성 제품에 대한 소비가 급증함에 따라 그 중요성이 높아지고 있다. 산초(Zanthoxylum schinfolium)는 limonene, citronellal, phellandrene 등의 다양한 유효물질을 함유하고 있으며 유효성분들로부터 유래되는 항산화 활성과 항암활성, 항균활성 등의 효능을 지니는 것으로 보고된바 있다. 본 연구의 생물전환 공정에 사용된 유산균들은 전통 발효식품으로 알려진 다양한 젓갈류로부터 분리하였으며, 16S rDNA 염기서열 분석을 통해 유전학적 특성을 확인하였다. 또한 확보된 유산균들을 사용하여 산초(전북 진안군) 분말의 발효공정을 수행하였으며, 산초의 최적 추출조건을 선정하고 추출물을 제조하여 생물전환 공정 전 후 활성의 변화추이를 관찰하였다. 추출물의 활성평가는 항산화 효능 및 유효성분 함량을 평가하기 위하여 DPPH radical scavenging activity와 total polyphenol 함량을 평가하고 세포주를 활용해 MTT assay, Nitric oxide(NO) 생성억제 효능을 확인하여 세포독성 및 항염증 활성을 확인하였다. 실험결과, 생물전환 공정에 사용할 유용 미생물을 확보하기 위한 실험을 통해 다양한 젓갈류에서 다양한 미생물을 확보할 수 있었으며 약 16종의 유산균을 분리하였다. 분리된 미생물을 사용하여 산초 분말의 생물전환 공정을 실시한 결과, 5종의 유용미생물 처리에서 무처리 대비 DPPH radical 소거능 및 polyphenol 함량이 유의적으로 증가됨을 확인할 수 있었다. 그 중 가장 높은 활성을 나타내는 균주를 16S rDNA 염기서열 분석을 통해 확인한 결과 Weissella confusa D1로 확인되었다. 선별 균주를 활용한 생물전환 공정 후 항산화 활성은 대조군 대비 약 120%의 활성을 나타냈으며, polyphenol의 함량은 약 126%로 증가하는 것을 확인할 수 있었다. 더 나아가 생물전환 공정 후 산초추출물의 세포독성은 처리전과 비교하여 월등히 감소하는 경향을 확인할 수 있었으며, 항염효능 또한 증가하는 경향을 나타내는 것이 확인되었다.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.383-395
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• 2014

When we investigated seed infestation by fungal pathogens from 51 varieties in 9 crops, the contamination rate of rice and sesame seeds was high. Therefore, to control seed-borne diseases, we obtained extracts from commercial products of Kimchi, Gochujang, Doenjang, Ganjang, Makgeolli and Tohajut and their suppressive effects against seed-borne diseases were studied. In addition, bacterial strains were screened to control rice seed-borne diseases in vitro and in vivo. Among forty food extracts, eleven food-extracts suppressed incidence of seedling rots in vitro and five food extracts increased 8-33% of healthy seedling in the greenhouse. Among 218 isolates from 40 fermented foods, 43 isolates showed high antifungal activity against seven fungal pathogens. When we tested 43 isolates for the reduction of rice seed borne disease, 32 isolates were able to reduce the rice seed borne disease. Among 32 isolates, 17 isolates reduced significantly seedling rot and increased healthy seedlings, the other isolates except for Kc4-2 and Mkl 2-2 increased shoot emergence and the percentage of healthy plants. Thirty isolates with high antifungal activity and suppressive effect against rice seedling rots were identified by 16S rRNA sequencing. Twenty one of thirty isolates were identified as Bacillus spp. Three isolates from Makgeolli were identified as Saccharomyces cerevisiae. B. amyloliquifaciens were isolated from six Korean traditional fermented foods except for Ganjang. B. amyloliquifaciens were majority in the effective bacterial population of Gochujang and Jutgal. Relatively diverse Bacillus species including B. subtilis, B. pumilus, and B. amyloliquificiens were isolated from Kimchi. The selected effective microorganisms from Korean fermented foods founded to be effective for controlling seed-borne diseases of rice in vitro and in the greenhouse. We think that Korean fermented foods and their useful microorganisms can be used as biocontrol agents for suppressing rice seed-borne diseases based on above described results.