• Korean Journal of Microbiology
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• v.44 no.1
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• pp.74-79
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• 2008

The purpose of this study is to clone cgt gene from Paenibacillus sp. JB-13 and to overexpress the protein in E. coli. For this purpose, the cgt gene was amplified from Paenibacillus sp. JB-13 genomic DNA by PCR using degenerate oligonucleotide primers. The sequence analysis results showed that the cgt gene from Paenibacillus sp. JB-13 has 98% homology with the cgt gene of Bacillus sp. To overexpress the protein, the cgt gene was cloned into pEXP7 expression vector and transformed into E. coli. The production of CGTase by recombinant E. coli was optimized under following conditions: 0.5% glucose, 3.0% polypeptone, 0.3% $K_2HPO_4$, 0.5% NaCl, and 7.0 of initial pH, 2.0% of inoculum, $37^{\circ}C$ of culture temperature for 14 hr. And the optimal agitation was found at 0.1 vvm. The synthesis of 2-O-${\alpha}$-D-Glucopyranosyl L-Ascorbic acid (AA-2G) using the CGTase expressed in E. coli was identified as AA-2G by HPLC and HPLC confirmed that treating AA-2G made by cloned CGTase with ${\alpha}$-glucosidase substantially produced AA and glucose.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.384-390
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• 2018

Air and soil are being contaminated by the environmental pollution as a result of climate change and urbanization, resulting in water pollution reaching serious levels. In this studies, we investigated the use of antimicrobial copper for the removal of biological pollutants from water system. Specifically, we tested its effects against E. coli, B. subtilis, S. aureus, K. pneumoniae and P. aeruginosa. Made a sphere shape having a diameter of 2cm using a strip-shaped copper wire of 0.5g, 1g and 2g. And then, to confirm the antimicrobial activities, each copper ball was equipped in the broth which inoculated each pathogens. The results showed that bacterial growth of the five test bacteria was inhibited by more than 99% after reaction with a 0.5 g copper ball for at least 20 minutes. Based on the these results, if perform the further experiment such cytotoxicity, it is expected that will be enough to be used as a filter for water quality purification. The developed technique is expected to be widely applied in various industries.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.205-211
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• 2006

Jeung-pyun was irradiated at 0, 5, 10 kGy and pH, reducing sugar, microbiological quality, texture profile analysis and sensory quality were investigated during storage for 2 weeks at $25^{\circ}C$. Irradiation significantly reduced total bacteria counts and indicated an increase in hardness with increasing irradiation dose. Treatments with 5, 10 kGy did not cause significant change in the PH, reducing sugar, but pH, reducing sugar, microbacterial counts in 0 kGy were increased during storage. Main putrefactive microorganisms of Jeung-pyun were identified as Bacillus subtlis. In texture profile analysis, cohesiveness and chewiness of all irradiated samples were observed to reduce during storage. In the result of sensory evaluation, the irradiated samples had higher scores than non-irradiated samples after 4 days.

• Preventive Nutrition and Food Science
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• v.9 no.1
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• pp.45-52
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• 2004

Effects of dietary calcium lactate (CaL-A) and Chungkukjang (Korean native fermented soybean) on bone mass, calcium status, body weight, serum glucose and cholesterol levels in young male rats were investigated. Chungkukjang was fermented by mixing 4 types of Bacillus sp., and then dried at 45$^{\circ}C$. Calcium lactate was prepared from the ash of black snail. The rats were fed a commercial rat diet for 1 week and then the experimental diets for 4 weeks. Animals were divided into four dietary groups: one calcium-deficient diet (Ca-De) and one of three with calcium supplemented diets (5 g calcium/kg diet) with either calcium phosphate (Ca-P), CaL-A, or CaL-A + Chuntkukjang (CaL-AC). Calcium supplemented diets contained 39 g Ca-P/kg diet and 28 g/kg of calcium lactate in the CaL-A and CaL-AC diets. Body weight gains during the 4 weeks in the Ca-P, CaL-A, CaL-AC and Ca-De groups were 130.45 g,112.50 g, 143.40 g and 10.20 g, respectively. Feed consumption of the groups from high to low was CaL-AC > Ca-P > CaL-A > Ca-De. The Ca-De group had low femur weights and low serum calcium concentrations, while they were comparatively high in CaL-AC, Ca-P and CaL-A groups. The Ca-De groups excreted less calcium in urine than did the other rats, probably due to increased absorption of the mineral in Ca-P, CaL-A and CaL-AC groups. Microscopic observations revealed that there were many regularly spaced holes in the femur of Ca-De group, while there were much smaller regularly spaced holes in Ca-P group. However, no holes in femur were observed in the CaL-A and CaL-AC groups. Bone surfaces were especially smooth and clean in the CaL-AC group. Serum concentrations of glucose and total cholesterol were remarkably lower in the CaL-AC group than in the other supplemented groups. These results suggest that calcium from CaL-A has higher bioavailability than from Ca-P, and dietary Chungkukjang may have a beneficial effect on calcium metabolism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.401-406
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• 2000

In development of the processed food, it is important not only to make the food delicious but to enhance its storage span and thermal stability without change of the food quality in color, which greatly affects the tastes of customers. Protopectinase (PPase) from Bacillus subtilis EK11 hydrolyses or dissolves protopectin in the middle lamella of plant tissues with the resultant separation of plant cells from each other, called enzymatic maceration. With the PPase, Kiwifruit was enzymatically macerated to separate cells to primary cell wall without damage. Yields of kiwifruit treated with PPase and mechanical maceration were 82% and 60%, respectively. Total and reducing sugars, crude protein and fat in the enzymatic maceration were well preserved as in the mechanical maceration. Importantly, over 95% of vitamin C, which is the most unstable component in application of the mechanical maceration, remained with intact form for one day after the enzymatic treatment. When the suspensions of kiwifruit macerated with both treatments had been stored at $4^{\circ}C for 6 days, the suspension of kiwifruit mechanically macerated was decolorized. whereas decolorization was not found in the enzymatically macerated kiwifruit. Moreover, the mechanically macerated kiwifruit was greatly deteriorated after heat treatment at $100^{\circ}C for 60 min ; the cell suspension of the exzymatically separated kiwifruit appeared to be stable, indicating the thermal stability. Thus, the PPase treatment could be a better choice for preparation of the highly valuable and functional processed food of kiwifruit as well as for prolonging the preservation period of the processed kiwifruit.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.663-669
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• 2007

The solvent extracts of Sargassum muticum, which were extracted by using several solvents with different polarities, were prepared for use as natural preservatives. The S. muticum extract with 80% ethanol was sequentially fractionated with n.hexane, dichloromethane, ethylacetate, and butanol. In order to effectively screen for natural preservatives agents, we first investigated the antioxidant activities such as DPPH radical scavenging capacity, superoxide radical scavenging capacity, and xanthine oxidase inhibitory activity of the S. muticum extracts. Through the screening system, we found that dichloromethane and ethylacetate fraction had high antioxidant activity with increments of the extract concentration. The antimicrobial activities and cell growth inhibition were investigated for each strain with the different concentrations of S. muticum extracts. Antimicrobial activities were shown in ethanol, dichloromethane, and n.hexane fractions of S. muticum. However, butanol, ethylacetate and water fractions showed weak antimicrobial activity against the tested microorganisms. Among the five fractions, dichloromethane fraction showed the highest antimicrobial activities against microorganisms tested, such as Bacillus sublitis, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis and Pseudomonas aeruginosa. The polyphenolic compounds from ethanol, n.hexane, dichloromethane, ethylacetate, butanol, and water fractions were 63.96 mg/g, 8.49 mg/g, 28.11 mg/g, 172.64 mg/g, 114.56 mg/g, and 34.91 mg/g, respectively. The dichloromethane fraction could be suitable for development as a food preservative.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.501-509
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• 2012

A 990 bp full-length gene (xynAHJ2) encoding a 329-residue polypeptide (XynAHJ2) with a calculated mass of 38.4 kDa was cloned from Bacillus sp. HJ2 harbored in a saline soil. XynAHJ2 showed no signal peptide, distinct amino acid stretches of glycoside hydrolase (GH) family 10 intracellular endoxylanases, and the highest amino acid sequence identity of 65.3% with the identified GH 10 intracellular mesophilic endoxylanase iM-KRICT PX1-Ps from Paenibacillus sp. HPL-001 (ACJ06666). The recombinant enzyme (rXynAHJ2) was expressed in Escherichia coli and displayed the typical characteristics of low-temperature-active enzyme (exhibiting optimum activity at $35^{\circ}C$, 62% at $20^{\circ}C$, and 38% at $10^{\circ}C$; thermolability at ${\geq}45^{\circ}C$). Compared with the reported GH 10 low-temperature-active endoxylanases, which are all extracellular, rXynAHJ2 showed low amino acid sequence identities (<45%), low homology (different phylogenetic cluster), and difference of structure (decreased amount of total accessible surface area and exposed nonpolar accessible surface area). Compared with the reported GH 10 intracellular endoxylanases, which are all mesophilic and thermophilic, rXynAHJ2 has decreased numbers of arginine residues and salt bridges, and showed resistance to $Ni^{2+}$, $Ca^{2+}$, or EDTA at 10 mM final concentration. The above mechanism of structural adaptation for low-temperature activity of intracellular endoxylanase rXynAHJ2 is different from that of GH 10 extracellular low-temperature-active endoxylanases. This is the first report of the molecular and biochemical characterizations of a novel intracellular low-temperature-active xylanase.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2159-2170
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• 2016

Many plant-pathogenic bacteria are dependent on quorum sensing (QS) to evoke disease. In this study, the population of QS and quorum quenching (QQ) bacteria was analyzed in a consecutive monoculture system of Pseudostellaria heterophylla. The isolated QS strains were identified as Serratia marcescens with SwrIR-type QS system and exhibited a significant increase over the years of monoculture. Only one QQ strain was isolated from newly planted soil sample and was identified as Bacillus thuringiensis, which secreted lactonase to degrade QS signal molecules. Inoculation of S. marcescens to P. heterophylla root could rapidly cause wilt disease, which was alleviated by B. thuringiensis. Furthermore, the expression of lactonase encoded by the aiiA gene in S. marcescens resulted in reduction of its pathogenicity, implying that the toxic effect of S. marcescens on the seedlings was QS-regulated. Meanwhile, excess lactonase in S. marcescens led to reduction in antibacterial substances, exoenzymes, and swarming motility, which might contribute to pathogensis on the seedlings. Root exudates and root tuber extracts of P. heterophylla significantly promoted the growth of S. marcescens, whereas a slight increase of B. thuringiensis was observed in both samples. These results demonstrated that QS-regulated behaviors in S. marcescens mediated by root exudates played an important role in replanting diseases of P. heterophylla.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.689-699
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• 2020

Brevibacillus brevis GZDF3 is a gram-positive, plant growth-promoting rhizosphere bacterium (PGPR) isolated from the rhizosphere soil of Pinellia ternata (an important herb in traditional Chinese medicine). The GZDF3 strain produces certain active compounds, such as siderophores, which are the final metabolite products of non-ribosomal peptide synthetase (NRPS) and independent non-ribosomal peptide synthetase (NIS) activity. With the present study, we attempted to investigate the siderophore production characteristics and conditions of Bacillus sp. GZDF3. The antibacterial activity of the siderophores on pathogenic fungi was also investigated. Optimal conditions for the synthesis of siderophores were determined by single factor method, using sucrose 15 g/l, asparagine 2 g/l, 32℃, and 48 h. The optimized sucrose asparagine medium significantly increased the production of siderophores, from 27.09% to 54.99%. Moreover, the effects of different kinds of metal ions on siderophore production were explored here. We found that Fe³⁺ and Cu²⁺ significantly inhibited the synthesis of siderophores. The preliminary separation and purification of siderophores by immobilized-metal affinity chromatography (IMAC) provides strong antibacterial activity against Candida albicans. The synergistic effect of siderophores and amphotericin B was also demonstrated. Our results have shown that the GZDF3 strain could produce a large amount of siderophores with strong antagonistic activity, which is helpful in the development of new biological control agents.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.383-392
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• 2006

This study was conducted to investigate the effects of a supplemented mixture of herbs (artemisia, eucommia ulmoids and houttuynia cordata) on the growth performance, nutrient utilization, blood characteristics, microflora population and diarrhea frequency in weanling pigs. Eighty-four pigs were randomly allotted into one of the four dietary treatments, each of which had 3 replicates. Experimental diets were prepared by adding (0.0, 0.5, 1.0 and 2.0%) a mixture of artemisia, eucommia ulmoids and houttuynia cordata to a commercial feed, and were given to pigs for 42 days. Daily feed intake was significantly increased in the groups supplemented with the mixture at 1.0% group and 2.0% group. Digestibility was significantly increased in 1.0% for protein and ether extract, and in 1.0% group and 2.0% group for NFE. Total bacillus and lactobacillus sp. were significantly (p<0.05) improved in 1.0% group and 2.0% group, respectively. Glucose concentrations of serum increased significantly (p<0.05) in 0.5% group and 1.0% group, and HDL increased significantly (p<0.05) in 1.0% group and 2.0% group. Diarrhea decreased by treatments except control (p<0.05). It is concluded that pigs fed the diet supplemented with 1.0% mixture of herbs can improve daily body weight gain, feed efficiency, nutrient utilizations and diarrhea frequency in pigs.