• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.431-440
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• 2008

Brucellosis is one of the most important zoonosis in worldwide. As one of the control measures, attempts have been made to develop new diagnostic methods using filed isolates as a national policy in many countries. Currently, bovine brucellosis in Korea have been received attention in both public health and economical aspects due to sudden increase of outbreak. Based on the situation, we compared standard strain (B. abortus 1119-3) with field isolates to reveal the differences among them. Biological and biochemical charateristics, antibiotic resistance profiles, outer membrane proteins (OMPs) and lipopolysaccharide analysis of the strains were included in this study. For the diagnostic purpose, an attempt was made to find out a novel antigen from the Korean isolates by serological analysis. There were differences about 55 kDa, 36-38 kDa and 20 kDa in analysis of OMPs by SDS-PAGE and Western blot with positive sera ($\geq$ 1:400 in SAT titer). Also, a serological diagnostic method, ELISA was conducted using OMPs of the strains as novel antigen. Relationships between O.D. and SAT titer were analyzed using field sera showing different SAT titer. High correlation coefficient was observed between SAT titer and ELISA. Results from this study suggested that a new diagnsotic method should be developed using their own field isolates in each country.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.104-110
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• 2004

To determine evolution and genotype of new chromosomal AmpC $\beta$-lactamases among clinical isolates of Enterobacter species, we performed antibiotic susceptibility testing, pI determination, sequencing, and phy-logenetic analysis using developed expression/secretion vector. Six isolates have shown to produce AmpC $\beta$-lactamases. Six genes of AmpC $\beta$-lactamases that are responsible for the resistance to cephamycins (cefoxitin and cefotetan), amoxicillin, cephalothin, and amoxicillin-clavulanic acid were cloned and characterized in pMSG12119. Insert fragment containing the ampC genes was sequenced and found to have an open reading frame coding for 381-amino-acid $\beta$-lactamase. The nucleotide sequence of four ampC genes ($bla_EcloK992004.l$, $bla_EcloK995120.1$, $bla_EcloK99230$, and $bla_EareK9911729$) shared considerable homology with that of chromosomal ampC gene ($bla_EcloMHN1$) of E. cloacae MHN1 (more than 99.6% identity). The sequences of two ampC genes ($bla_EcloK9973$ and $bla_EcloK9914325$) showed close similarity to the chromosomal ampC gene ($bla_EcloQ908R$) of E. clo-acae 908R (99.7% identity). The results from phylogenetic analysis suggested that six ampC genes could be originated from $bla_EcloMHN1$ / or $bla_EcloQ908R$ / MIC patterns and exact pI values of six transformants indicated that the developed expression/secretion vector (pMSG1219) was suitable for the characterization of foreign genes in E. coli strain.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.260-267
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• 2008

The choice of expression vector is very important for industrial production of proteins. Therefore, the systematic mining of promoters over a wider range of genetic resource and/or host is required. We previously reported a novel bidirectional reporting system (pBGR) for the isolation of promoters from metagenome and screened useful promoters that functioned constitutively in E. coli under general culture conditions. Among them, three promoter sequences including each upstream region were amplified by PCR and used to construct new expression vectors. To facilitate subcloning, a multi-cloning site was incorporated into the downstream region of the revere primer sequence. At these sites, GFP, esterase and $\beta$-glucosidase were subcloned and analyzed the constitutive expression ability of new promoter in terms of protein solubility and expression level. As a result, these vectors expressed the proteins constitutively to a level of $2{\sim}3%$ of the total cell protein in soluble fraction (>80 %). This study suggested that excavation of metagenomic promoters for construction of expression vector in a certain strain could provide a way for the development of the expression systems.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.195-204
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• 2004

Poisson's ratio due to multiaxial creep of concrete reported by existing experimental works was controversial. Poisson's ratio calculated from measured strain is very sensitive to small experimental error. This sensitivity make it difficult to find out whether the Poisson's ratio varies with time or remain constant, and whether the Poisson's ratio has different value with stress states or not. A new approach method is needed to resolve the discrepancy and obtain reliable results. This paper presents analytical study on multiaxial creep test results. Microplane model as a new approach method is applied to optimally fitting the test data extracted from experimental studies on multiaxial creep of concrete. Double-power law is used as a model to present volumetric and deviatoric creep evolutions on a microplane. Six parameters representing the volumetric and deviatoric compliance functions are determined from regression analysis and the optimum fits accurately describe the test data. Poisson's ratio is calculated from the optimum fits and its value varies with time. Regression analysis is also performed assuming that Poisson's ratio remains constant with time. Four parameters are determined for this condition, and the error between the optimum fits and the test data is slightly larger than that for six parameter regression results. The constant Poisson's ratio with time is obtained from four parameter analysis results and the constant value can be used in practice without serious error.

• Journal of Mushroom
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• v.4 no.1
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• pp.1-32
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• 2006

According to UPOV (International Union for Protection of New Varieties of Plants), mushroom spawn market have to be opened by the year 2009. Number of commercial strains distributed by the year 2005 were 179 of 24 species of edible and medicinal mushrooms. Only nine strains of oyster mushrooms were registered as protected variety, which is not compatible with those recorded in other advanced countries. Meaning of spawn in broad sense contains commercial strains. Development of commercial strains faces two main problems in Korea : One is the complicated genetic patterns and sexuality of mushroom species, and the other is expensive experimental equipments and fruiting body growing houses. Resolution of these problems leads to development of mushroom strains. This could be achieved as follows; genetic resources collection and assessment, molecular characterization of useful genetic characters, development of new commercial strains by hybridization using typical genetic resources, strengthening of breeding research using "Mushroom Breeding Group", management of spawn research company by consortium, foundation of mushroom general industry, promotion of consumption, and upgrade of competition ability for other countries. These points are under discussion.

• Biomedical Science Letters
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• v.26 no.3
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• pp.230-237
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• 2020

Staphylococcus aureus (S. aureus) is known as a bacterium that can cause skin infections, respiratory system infections, and sinusitis; however, it can exist as a normal flora rather than a pathogen. Recently, methicillin-resistant S. aureus (MRSA) infections have emerged in the community as a new variant of community-associated (CA)-MRSA. In the present study, S. aureus and MRSA were isolated and cultured by collecting samples from facilities and environments where students and educational personnel have multiple contacts on university campuses; specifically, the nostrils and hands of college students were tested from July to September of 2019. The molecular properties of the isolated MRSA were analyzed, and the one MRSA strain was isolated from the university campuses. One MRSA that was isolated and cultured on campus was the mec complex group A and staphylococcal cassette chromosome (SCC) mec type II, which is a characteristic of healthcare-associated (HA)-MRSA, and SCCmec type V, which is a characteristic of CA-MRSA. This result was similar to other studies wherein the SCCmec type II was detected in SCCmec typing analysis in CA-MRSA. To confirm whether there is a new variant of CA-MRSA in the Republic of Korea, additional follow-up studies on the analysis of virulence factors of MRSA are needed by additionally separating CA-MRSA from the body parts of university students and educational personnel.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.180-185
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• 2015

Leaf discs from 'Yeobong' and 'Maehyang' strawberry plants were used as explants for transformation. The Agrobacterium tumefaciens strain EHA105 harboring the monellin gene under the control of the CaMV 35S promoter was used in co-cultivation experiments. The frequencies of callus formation and plant regeneration from leaf explants after co-cultivation in 'Yeobong' were higher than those of 'Maehyang'. These transgenic plants showed normal growth patterns and flowering. PCR and Southern hybridization confirmed that 1 to 2 copies of the monellin gene were integrated into genome of the transgenic strawberry plants. Northern blot analysis confirm that the transcripts were expressed in transgenic strawberry plants. Although long-term subcultured transgenic strawberry plants showed a phenomenon to escape the transgene, the transformation system established in this study provides new opportunities for genetic improvement of strawberry plants.

• Journal of Mushroom
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• v.9 no.1
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• pp.17-21
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• 2011

Dahyang, a CNARES's newly bred cultivar, is a CM061202 strain isolated and selected from 161 single-spores of brown button mushroom. It was selected as a new cultivar after comparison of yield, mycelial growth and quality with No. 705. Mycelial growth of Dahyang on compost extract mushroom complete medium at $25^{\circ}C$ for 15 days was 63mm when it was compared with that of No. 705 with 38mm. The cultivation temperature of Dahyang was 15 to $19^{\circ}C$ which was $2^{\circ}C$ higher than that of No. 705 with 15 to $19^{\circ}C$ cultivated on rice straw bed. The color of pileus of Dahyang was brown. Pinhead producing period was 30 days which is 1 day late than that of No. 705 with 29 days. Dahyang yielded 37% more with $49.1kg/3.3m^2$ than that of No. 705 with $35.8kg/3.3m^2$, respectively. The weight was 16.0g which was heavier than 14.0g of No. 705. The thickness and diameter were also more than those of No. 705. The stipe was shorter and thicker than that of No. 705. Also physical characteristics such as hardness and elasticity were better than that of No. 705.

• Journal of Mushroom
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• v.5 no.2
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• pp.86-90
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• 2007

Jeakdan', a new variety of pink oyster mushroom was bred in Mushroom Research Institute, Gyeonggido Agricultural Research & Extension Services in 2006. This pink oyster mushroom was selected one which cross with monokaryon collected from strain KME20063 and KME20193. The major characteristics of the mushroom were showed a lot of pinheadings, the pink-colored and infundibuliform pileus. The optimum temperature for the mycelial growth was around $26{\sim}30^{\circ}C$ and that for the primordia and growth of fruitbody was around $18{\sim}23^{\circ}C$. Primordia and young fruiting bodies were bright pink but become less intensely colored while the mushroom were mature. Incubation period was required about 20 days in bottle culture and 21 days in bag culture. Number of valid stipes was 31.5/850cc bottle and 47.0/2kg bag. The fruiting body yield was 134.5g/850cc bottle and 350.0g/2kg bag.

• Journal of Mushroom
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• v.15 no.1
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• pp.25-30
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• 2017

'Baekseung', a new variety of Flammulina velutipes, was bred by mating two monokaryotic strains isolated from KMCC 4210 and KMCC 4216 in the Mushroom Research Division, Baekseung ARES in 2016. The Baekseung and Uri1ho strains showed fast mycelial growth and mycelial density on malt extract agar media after 7 days of incubation. The spawn running period on the sawdust substrate required a cultivation period and temperature of 30 days and $25^{\circ}C$, respectively, for primordia formation where in fruiting body development occurred from $11{\pm}1days$ at $14^{\circ}C$ and $14{\pm}1days$ at $7^{\circ}C$. The length of the pilei and stipes of the Baekseung harvested in optimal stag were $11.3{\pm}0.4$ and $89.2{\pm}7.1mm$, respectively, whereas the values for Uri1ho were $10.7{\pm}1.0$ and $91.3{\pm}20.8mm$, respectively. The yield of the Baekseung and Uri1ho strain grown on the sawdust substrate was $153.7{\pm}12.5$ and $139.8{\pm}17.8g$, respectively, per 850 ml in bottle cultivation. The inferred tree exhibited a phylogenetic relationship between the Korean white fruiting body strains of Baekseung, Uri1ho and Fv-14-a-38, Fv-14-a-51, and the Japanese white fruiting body-forming strains of KMCC 4226, and these were confirmed to be genetically related.