• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.888-897
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• 2009

Lipase diversity in glacier soil was assessed by culture-independent metagenomic DNA fragment screening and confirmed by cell culture experiments. A set of degenerate PCR primers specific for lipases of the hormone-sensitive lipase family was designed based on conserved motifs and used to directly PCR amplify metagenomic DNA from glacier soil. These products were used to construct a lipase fragment clone library. Among the 300 clones sequenced for the analysis, 201 clones encoding partiallipases shared 51-82% identity to known lipases in GenBank. Based on a phylogenetic analysis, five divergent clusters were established, one of which may represent a previously unidentified lipase subfamily. In the culture study, 11 lipase-producing bacteria were selectively isolated and characterized by 16S rDNA sequences. Using the above-mentioned degenerate primers, seven lipase gene fragments were cloned, but not all of them could be accounted for by the clones in the library. Two full-length lipase genes obtained by TAIL-PCR were expressed in Pichia pastoris and characterized. Both were authentic lipases with optimum temperatures of ${\le}40^{\circ}C$. Our study indicates the abundant lipase diversity in glacier soil as well as the feasibility of sequence-based screening in discovering new lipase genes from complex environmental samples.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.696-700
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• 2013

A quick and reliable method for identifying meat origin is developed to ensure species origin of livestock products for consumers. The present study examined the identification of meat sources (duck, chicken, goat, deer, pig, cattle, sheep, and horse) using PCR by exploiting the mitochondrial 12S rRNA and mitochondrial cytochrome b genes. Species-specific primers were designed for some or all mitochondrial 12S rRNA nucleotide sequences to identify meat samples from duck, chicken, goat, and deer. Mitochondrial cytochrome b genes from pig, cattle, sheep, and horse were used to construct species-specific primers, which were used to amplify DNA from different meat samples. Primer sets developed in this study were found to be superior for detecting meat origin when compared to other available methods, for which the discrimination of meat origin was not equally applicable in some cases. Our new development of species-specific primer sets could be multiplexed in a single PCR reaction to significantly reduce the time and labor required for determining meat samples of unknown origin from the 8 species. Therefore, the technique developed in this study can be used efficiently to trace the meat origin in a commercial venture and help consumers to preserve their rights knowing origin of meat products for social, religious or health consciousness.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.235-240
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• 1999

The usefulness of randomly amplified polymorphic DNA (RAPD) was evaluated to access the genetic variation in somaclones derived from different cytotype plants of Scilla scilloides Complex, AA (2n=16), BB (2n=18) and AABB (2n=34). Three arbitrary decamer primers were successfully used to amplify genomic DNA from the somaclones. DNA polymorphism was observed between cytotypes. The total number of bands in AA, BB and AABB somaclones were 110, 116 and 103, and marker bands examined were 15, 19 and 26, respectively. The diversity of types using PCR in AA, AABB and BB somaclones were 39.2%, 72.3% and 45.7%, respectively. RAPD band patterns suggest that type AA is more stable than type BB and AABB. The frequencies of specific band in AA, BB or AABB somaclones were 0.9%, 4.3% and 4.9%, respectively. The applicability and reliability of RAPD markers for evaluating the somaclones are discussed.

• Genomics & Informatics
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• v.10 no.4
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• pp.249-255
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• 2012

In this study, fosmid cloning strategies were used to assess the microbial populations in water from the International Space Station (ISS) drinking water system (henceforth referred to as Prebiocide and Tank A water samples). The goals of this study were: to compare the sensitivity of the fosmid cloning strategy with that of traditional culture-based and 16S rRNA-based approaches and to detect the widest possible spectrum of microbial populations during the water purification process. Initially, microbes could not be cultivated, and conventional PCR failed to amplify 16S rDNA fragments from these low biomass samples. Therefore, randomly primed rolling-circle amplification was used to amplify any DNA that might be present in the samples, followed by size selection by using pulsed-field gel electrophoresis. The amplified high-molecular- weight DNA from both samples was cloned into fosmid vectors. Several hundred clones were randomly selected for sequencing, followed by Blastn/Blastx searches. Sequences encoding specific genes from Burkholderia, a species abundant in the soil and groundwater, were found in both samples. Bradyrhizobium and Mesorhizobium, which belong to rhizobia, a large community of nitrogen fixers often found in association with plant roots, were present in the Prebiocide samples. Ralstonia, which is prevalent in soils with a high heavy metal content, was detected in the Tank A samples. The detection of many unidentified sequences suggests the presence of potentially novel microbial fingerprints. The bacterial diversity detected in this pilot study using a fosmid vector approach was higher than that detected by conventional 16S rRNA gene sequencing.

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.334-340
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• 1998

This research was conducted to identify plant regulatory regions by gene tagging method. A promoterless GUS coding sequence was introduced to Populus nigra ${\times}$ P. maximowiczii via Agrobacterium strains(LBA4404/EHA101), and putative transgenic poplars were selected by culturing on medium containing G418($60mg/{\ell}$) and by GUS assay. Among them one positive plant was to amplify the native sequences flanking to the introduced GUS gene in plant genome by inverse PCR method and from this 730 by DNA product was obtained. After subcloning and sequencing, it has 88% homology to the Eucalyptus gunnii CAD(cinnamyl alcohol dehydrogenase) gene. The GUS gene fused with the putative promoter reinserted into poplar leaves by particle bombardment method to test the funtional promoter activity. Upon staining with X-gluc, many blue spots appeared on the leaf segments bombarded by the chimeric gene 2-3 days, thus the isolated DNA fragment contain some possible coding region as well as a putative regulatory sequences of poplar CAD gene.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.367-377
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• 1996

Genes on the long arm of Y chromosome, particularly interval 6, are believed to playa critical role in human spermatogenesis. The objective of this study was to validate a sequenced-tagged site(STS)-mapping strategy for the detection of Yq microdeletion and to use this method to determine the proportion of men with Yq microdeletions in idiopathic, obstructive, nonobstructive azoospermia, severe OATS and in normal males. We analyzed three STS markers mapped to interval 6 within long arm of the Y chromosome from 106 nonobstructive, 30 obstructive azoospermia, 15 severe OATS patients, and normal 42 males in Korean men. By PCR, we tested leukocyte DNA, for the presences of STS markers(DAZ, sY129 and sY134) and SRY gene as internal control. And PCR results were confirmed by Southern hybridization, and were investigated by SSCP analysis for DAZ gene mutation. None of 42 normal males and 30 obstructive azoospermia had microdeletions, Of the 15 severe OATS typed with DAZ, sY129 and sY134, 3(20.0%) patients failed to amplify 1 or more STS markers, and of the 106 nonobstructive azoospermia typed with DAZ, sY129 and sY134, 12(11.3%) patients failed to amplify 1 or more STS markers. From these results, high prevalence(12.4%) of Yq deletion(DAZ, sY129, sY134) in men with nonobstructive idopathic azoospermia and severe OATS were observed in Korean infertility patients. To avoid the infertile offspring by assisted reproductive technique using ICSI or ROSI, genetic diagnosis will be needed in IVF-ET program.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.88-89
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• 2013

A variety of influenza A viruses from animal hosts are continuously prevalent throughout the world which cause human epidemics resulting millions of human infections and enormous industrial and economic damages. Thus, early diagnosis of such pathogen is of paramount importance for biomedical examination and public healthcare screening. To approach this issue, here we propose a fully integrated Rotary genetic analysis system, called Rotary Genetic Analyzer, for on-site detection of influenza A viruses with high speed. The Rotary Genetic Analyzer is made up of four parts including a disposable microchip, a servo motor for precise and high rate spinning of the chip, thermal blocks for temperature control, and a miniaturized optical fluorescence detector as shown Fig. 1. A thermal block made from duralumin is integrated with a film heater at the bottom and a resistance temperature detector (RTD) in the middle. For the efficient performance of RT-PCR, three thermal blocks are placed on the Rotary stage and the temperature of each block is corresponded to the thermal cycling, namely $95^{\circ}C$ (denature), $58^{\circ}C$ (annealing), and $72^{\circ}C$ (extension). Rotary RT-PCR was performed to amplify the target gene which was monitored by an optical fluorescent detector above the extension block. A disposable microdevice (10 cm diameter) consists of a solid-phase extraction based sample pretreatment unit, bead chamber, and 4 ${\mu}L$ of the PCR chamber as shown Fig. 2. The microchip is fabricated using a patterned polycarbonate (PC) sheet with 1 mm thickness and a PC film with 130 ${\mu}m$ thickness, which layers are thermally bonded at $138^{\circ}C$ using acetone vapour. Silicatreated microglass beads with 150~212 ${\mu}L$ diameter are introduced into the sample pretreatment chambers and held in place by weir structure for construction of solid-phase extraction system. Fig. 3 shows strobed images of sequential loading of three samples. Three samples were loaded into the reservoir simultaneously (Fig. 3A), then the influenza A H3N2 viral RNA sample was loaded at 5000 RPM for 10 sec (Fig. 3B). Washing buffer was followed at 5000 RPM for 5 min (Fig. 3C), and angular frequency was decreased to 100 RPM for siphon priming of PCR cocktail to the channel as shown in Figure 3D. Finally the PCR cocktail was loaded to the bead chamber at 2000 RPM for 10 sec, and then RPM was increased up to 5000 RPM for 1 min to obtain the as much as PCR cocktail containing the RNA template (Fig. 3E). In this system, the wastes from RNA samples and washing buffer were transported to the waste chamber, which is fully filled to the chamber with precise optimization. Then, the PCR cocktail was able to transport to the PCR chamber. Fig. 3F shows the final image of the sample pretreatment. PCR cocktail containing RNA template is successfully isolated from waste. To detect the influenza A H3N2 virus, the purified RNA with PCR cocktail in the PCR chamber was amplified by using performed the RNA capture on the proposed microdevice. The fluorescence images were described in Figure 4A at the 0, 40 cycles. The fluorescence signal (40 cycle) was drastically increased confirming the influenza A H3N2 virus. The real-time profiles were successfully obtained using the optical fluorescence detector as shown in Figure 4B. The Rotary PCR and off-chip PCR were compared with same amount of influenza A H3N2 virus. The Ct value of Rotary PCR was smaller than the off-chip PCR without contamination. The whole process of the sample pretreatment and RT-PCR could be accomplished in 30 min on the fully integrated Rotary Genetic Analyzer system. We have demonstrated a fully integrated and portable Rotary Genetic Analyzer for detection of the gene expression of influenza A virus, which has 'Sample-in-answer-out' capability including sample pretreatment, rotary amplification, and optical detection. Target gene amplification was real-time monitored using the integrated Rotary Genetic Analyzer system.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.379-387
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• 2017

Various sizes (0.2 ~ 1.2 mm) and developmental stages (referred to as Stage 1 ~ 3) of apical and lateral meristems were excised, together or separately, directly from dormant buds of apple 'Hongro'. They were mixed infected by Apple scar skin viroid (ASSVd), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple stem grooving virus (ASGV), which are major viruses attacking apples. A total of 31 callus lines (> 10 mm in diameter) were obtained by culturing the explants on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA), and they were subjected to RT-PCR analysis for virus detection. A high rate of virus elimination (expressed as the percentage of calli that did not amplify during RT-PCR, i.e., RT-PCR negative calli per total number of calli obtained) was achieved for ACLSV (100%), ASSVd (93.7%), and ASPV (93.7%), whereas it was only 25.8% for ASGV. ASPV was detected in the presence of 2 ~ 3 bracts. Simultaneous virus elimination of ASSVd, ASPV, ACLSV, and ASGV occurred during the meristem culture, in which the early stages of the dormant buds (Stage 1) were used, because ASGV was mostly eliminated during that stage. The results of the present study will be valuable for the production of virus-free apple trees.

• Journal of Gastric Cancer
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• v.3 no.3
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• pp.128-133
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• 2003

Purpose: The benefits of the 'no-touch' isolation techniquethat is usually performed to prevent the circulation of tumor cells are not evident. The aim of this study was to determine whether the no-touch isolation technique for treating gastrointestinal cancers could prevent the circulation of tumor cells detected by reverse transcriptase polymerase chain reaction (RT-PCR). Matrials and Methods: By using RT-PCR to amplify mRNAs for two specific epithelial markers, carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20), we examined 34 gastric cancer patients who had been histologically diagnosed and 22 patients had undergone serosal and peritoneal brushing. Results: In 10 ($29.4\%$) of the 34 gastric cancer patients, we detected CK20 mRNA before manipulation, and in 17 ($51.5\%$) of those patients, after we detected it. The density of the CK20 mRNA band was increased in 11 cases ($33.3\%$) and the density was decreased in 2 cases ($6.1\%$). In 16 ($48.5\%$) of the 34 gastric cancer patients, we detected CEA mRNA before manipulation, and in 17 ($51.5\%$) patients after we detected it. The density of the CEA mRNA band was increased in 8 cases ($24.2\%$) and decreased in 3 cases ($9.1\%$). Conclusion: These result suggest that the ' no-touch isolation technique ' might be useful when operating on advanced gastric cancer patients and that serosal or Douglas pouch brushing can be used to determine the status of micrometastasis.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.41-41
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• 2015

Oomycetes belong to the kingdom Straminipila, a remarkably diverse group which includes brown algae and planktonic diatoms, although they have previously been classified under the kingdom Fungi. These organisms have evolved both saprophytic and pathogenic lifestyles, and more than 60% of the known species are pathogens on plants, the majority of which are classified into the order Peronosporales (includes downy mildews, Phytophthora, and Pythium). Recent phylogenetic investigations based on DNA sequences have revealed that the diversity of oomycetes has been largely underestimated. Although morphology is the most valuable criterion for their identification and diversity, morphological species identification is time-consuming and in some groups very difficult, especially for non-taxonomists. DNA barcoding is a fast and reliable tool for identification of species, enabling us to unravel the diversity and distribution of oomycetes. Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The mitochondrial cox2 gene has been widely used for identification, taxonomy and phylogeny of various oomycete groups. However, recently the cox1 gene was proposed as a DNA barcode marker instead, together with ITS rDNA. To determine which out of cox1 or cox2 is best suited as universal oomycete barcode, we compared these two genes in terms of (1) PCR efficiency for 31 representative genera, as well as for historic herbarium specimens, and (2) in terms of sequence polymorphism, intra- and interspecific divergence. The primer sets for cox2 successfully amplified all oomycete genera tested, while cox1 failed to amplify three genera. In addition, cox2 exhibited higher PCR efficiency for historic herbarium specimens, providing easier access to barcoding type material. In addition, cox2 yielded higher species identification success, with higher interspecific and lower intraspecific divergences than cox1. Therefore, cox2 is suggested as a partner DNA barcode along with ITS rDNA instead of cox1. Including the two barcoding markers, ITS rDNA and cox2 mtDNA, the multi-locus phylogenetic analyses were performed to resolve two complex clades, Bremia lactucae (lettuce downy mildew) and Peronospora effuse (spinach downy mildew) at the species level and to infer evolutionary relationships within them. The approaches discriminated all currently accepted species and revealed several previously unrecognized lineages, which are specific to a host genus or species. The sequence polymorphisms were useful to develop a real-time quantitative PCR (qPCR) assay for detection of airborne inoculum of B. lactucae and P. effusa. Specificity tests revealed that the qPCR assay is specific for detection of each species. This assay is sensitive, enabling detection of very low levels of inoculum that may be present in the field. Early detection of the pathogen, coupled with knowledge of other factors that favor downy mildew outbreaks, may enable disease forecasting for judicious timing of fungicide applications.