• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.71-76
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• 2018

Norovirus is a leading cause of sporadic pathogenic non-bacterial gastroenteritis worldwide. For the detection of norovirus, reverse transcription real-time PCR (RT qPCR) has quickly become a major tool due to its sensitivity and specificity. However, accurate viral RNA extraction methods are essential for RT qPCR analysis. TRIzol reagents are used to extract RNA from biological materials and are therefore widely used for norovirus RNA extraction. In this study, the yield of viral RNA extraction using TRIzol from genogroup II (GII) among the human norovirus genogroup I (GI) and GII, and murine norovirus (GV) depended on the pH of the virus sample solution. The yield of RNA extraction was higher at the alkaline pH than in the acidic region compared with the Ct (threshold cycle) value of the real-time PCR. From the results of this study, it was found that the pH condition is very important for the quantitative analysis of norovirus by extracting GII RNA using TRIzol.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.113-117
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• 1997

Simple sequence repeats (SSR) are widely dispersed throughout eukaryotic genomes, highly polymorphic, and easily typed using polymerase chain reaction (PCR). The objective of this study was to determine the polymorphism of different Chlamydomonas reinhartdtii strains and to determine the mode of inheritance of the SSR locus in Chlamydomonas. A genomic DNA library of C. reinhardtii was constructed and screened with a radiolabeled $(AC)_{11}$ probe for the selection of (CA/GT)n repeat clone. Selected clone was seqeuenced, and PCR primer set flanking (CA/GT)n sequence was constructed. PCR was used to specifically amplify the SSR locus from multiple isolates of C. reinhardtii. The locus was polymorphic in some of the C. reinhardtii isolates. However, the locus was amplified only 4 of 6 isolates of C. reinhardtii, not in other 2 isolates of C. reinhardtii, suggesting that this locus is not extensively conserved. A simple Mendelian inheritance pattern was found, which showed 2:2 segregation in the tetrads resulting from a cross between C. reinhardtii and C. smithii. Our results suggest that this simple sequence repeat DNA polymorphism will be useful for identity testing, population studies, linkage analysis, and genome mapping in Chlamydomonas.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.98-103
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• 1990

Brevibacterium lactofermentum SWA (arg trp) and B. lactofermentum SWB (met ser) were obtained from UV and NTG treatment. The rates of protoplast formation by B. lactofermentum SWA and SWB were 99.93% and 99.98%, respectively when each strain was treated with penicillin G in mid exponential growth phase, followed by incubation with 400 $\mu\textrm{g}$/ml of lysozyme in lysis fluid supplemented with 0.4M sucrose. Frequencies of protoplast regeneration in B. lactofermentum SWA and B. lactofermentum SWB were 9.27% and 10.32% respectively, on regeneration medium containing 0.5M sodium succinate, 50 mM $Mg^{2+}$, and 3% PVP. In intraspecific protoplast fusion between B. lactofermentum SWA and B. lactofermentum SWB, fusion frequency of $2.30\times 10^{-5}$ was observed by using the 100mM $CaCl_{2}$ and 30% PEG 6,000 in fusion fluid. Relative recombinant frequencies in each marker by means of selective media could be used for genetic analysis.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.928-932
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• 2009

Most diseases are caused by complex processes of various factors. Although previous researches have tried to identify the causes of the disease, there are still lots of limitations to clarify the complex factors. Here, we present a disease classification model based on an evolutionary learning approach of combinatorial features using the data sets from the genetics and cohort studies. We implemented a system for finding the combinatorial risk factors and visualizing the results. Our results show that the proposed method not only improves classification accuracy but also identifies biologically meaningful sets of risk factors.

• Korean Journal of Veterinary Service
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• v.39 no.1
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• pp.41-49
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• 2016

In the present study, fast and robust methods for the next generation sequencing (NGS) were developed for analysis of PRRSV full genome sequences, which is a positive sensed RNA virus with a high degree of genetic variability among isolates. Two strains of PRRSVs (VR2332 and VR2332-R) which have been maintained in our laboratory were used to validate our methods and to compare with the sequence registered in GenBank (GenBank accession no. EF536003). The results suggested that both of strains had 100% coverage with the reference; the VR2332 had the coverage depth from minimum 3 to maximum 23,012, for the VR2332-R from minimum 3 to maximum 41,348, and 22,712 as an average depth. Genomic data produced from the massive sequencing capacities of the NGS have enabled the study of PRRSV at an unprecedented rate and details. Unlike conventional sequence methods which require the knowledge of conserved regions, the NGS allows de novo assembly of the full viral genomes. Therefore, our results suggested that these methods using the NGS massively facilitate the generation of more full genome PRRSV sequences locally as well as nationally in regard of saving time and cost.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.141-146
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• 2012

A gene encoding the xylanase (XynA) predicted from partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by PCR. This xynA gene consisted of 633 nucleotides, encoding a polypeptide of 211 amino acid residues. The deduced amino acid sequence exhibited 85-89% identity with those of several Paenibacillus xylanases, belonging to the glycosyl hydrolase family 11. As a results of expression of the structural gene by T7 promoter of a pET23a(+) expression vector, xylanase activity was higher in cell-free extract than culture filtrate of a recombinant Escherichia coli BL21(DE3) CodonPlus. However, the expression level of xylanase was not sufficient be detected by SDS-PAGE. The cell-free extract showed maximal xylanase activity at $60^{\circ}C$ and pH 5.5. The predominant products resulting from xylan and xylooligosaccharide hydrolysis were xylose and xylotriose. The enzyme could hydrolyze xylooligosaccharides larger than xylbiose.

• KSBB Journal
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• v.20 no.5 s.94
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• pp.387-391
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• 2005

Totally 16,299 conservative genes, commonly found in 13 thermophilic and hyperthermophilic bacteria, were analyzed. All genes were belong to W 67 COGs (clusters of orthologous groups of proteins). COGs related to protein metabolism were 80 among 167 COGs. Conservative genes were not limited only thermophiles and hyperthermophiles, meaning thermal stability is independent of specific protein. However reverse gyrase was only found in all hyperthermophilic archaebacteria and eubacteria, meaning DNA stability is important in hyperthermophiles. Hyperthermophilic eubacteria and thermophilic archaebacteria had different position between phylogenetic tree of gene content and 165 rRNA gene. Thermophilic archaebacteria hyperthermophilic eubacteria and archaebacteria had similar values by the statistical analysis of distance values with 167 COGs in each organism.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.389-396
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• 2015

A coil design of pulse induction metal detectors has been described. The search coil was demonstrated by using the wire with the diameter of 0.3 mm, 0.5 mm and 1.0 mm and the dielectric plate with the $30cm{\times}30cm$ and $35cm{\times}35cm$, the time constant and the currents of the coil as the variation of the coil size and the number of coil turns was characterized. The coil parameters like the resistance, the inductance and the time constants as the variation of the diameter of the wire, the coil size and the number of coil turns were compared and analysed through the calculation and the measurement. In addition, investigating the coil currents as the variation of the input pulse width, the coil design of pulse induction metal detectors has been discussed.

• Korean Journal of Optics and Photonics
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• v.19 no.5
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• pp.381-385
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• 2008

We have analyzed the effect of the substrate removal and packaging schemes on light output characteristics in InGaN/Sapphire LEDs. The removal of the sapphire substrate helps to dissipate the heat generated in the junction, but the advantage comes only with the detrimental effect of degrading the photon extraction efficiency. If the substrate-removed chip is attached to a metallic mount with good thermal conductivity, the maximum driving current is increased drastically, producing significantly increased light output and therefore compensating the photon extraction efficiency degradation. On a dielectric mount with a relatively poor thermal conductivity, however, it produces smaller light output, over most input current range, than the regular type of chips with the sapphire substrate remaining. Thus, for low power applications, the regular chips may be preferred over the substrate-removed chips, regardless of the chip mounts employed.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.249-253
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• 2000

We have analyzed electrical characteristics of the amorphous $MgTiO_3$thin films deposited by pulsed laser deposition (PLD) technique with the temperature of 400~$500^{\circ}C$. The electrical characteristics of $MgTiO_3$films heavily depend on the deposition temperature. We speculate that the density of anomalous positive charge (APC) substantially increases as the deposition temperature lowers, causing the HF C-V curves shift to the direction of the negative gate voltage. We further observed that both the degree of C-V shift as a function of the deposition temperature and the density of APC were minimized by the use of $SiO_2$with thickness of approximately 100 $\AA$ between $MgTiO_3$films and the Si substrate.