• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2748-2760
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• 2018

This paper proposes an audio event classification method based on convolutional neural networks (CNNs). CNN has great advantages of distinguishing complex shapes of image. Proposed system uses the features of audio sound as an input image of CNN. Mel scale filter bank features are extracted from each frame, then the features are concatenated over 40 consecutive frames and as a result, the concatenated frames are regarded as an input image. The output layer of CNN generates probabilities of audio event (e.g. dogs bark, siren, forest). The event probabilities for all images in an audio segment are accumulated, then the audio event having the highest accumulated probability is determined to be the classification result. This proposed method classified thirty audio events with the accuracy of 81.5% for the UrbanSound8K, BBC Sound FX, DCASE2016, and FREESOUND dataset.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1242-1248
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• 2007

Genomic analysis of a hyperthermophilic archaeon, Thermococcus onnurineus NA1 [1], revealed the presence of an open reading frame consisting of 1,377 bp similar to ${\alpha}$-amylases from Thermococcales, encoding a 458-residue polypeptide containing a putative 25-residue signal peptide. The mature form of the ${\alpha}$-amylase was cloned and the recombinant enzyme was characterized. The optimum activity of the enzyme occurred at $80^{\circ}C$ and pH 5.5. The enzyme showed a liquefying activity, hydrolyzing maltooligosaccharides, amylopectin, and starch to produce mainly maltose (G2) to maltoheptaose (G7), but not pullulan and cyclodextrin. Surprisingly, the enzyme was not highly thermostable, with half-life ($t_{1/2}$) values of 10 min at $90^{\circ}C$, despite the high similarity to ${\alpha}$-amylases from Pyrococcus. Factors affecting the thermostability were considered to enhance the thermo stability. The presence of $Ca^{2+}$ seemed to be critical, significantly changing $t_{1/2}$ at $90^{\circ}C$ to 153 min by the addition of 0.5 mM $Ca^{2+}$. On the other hand, the thermostability was not enhanced by the addition of $Zn^{2+}$ or other divalent metals, irrespective of the concentration. The mutagenetic study showed that the recovery of zinc-binding residues (His175 and Cys189) enhanced the thermo stability, indicating that the residues involved in metal binding is very critical for the thermostability.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.439-446
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• 2009

The biosynthesis study of antibiotics saframycin (SFM) in Streptomyces lavendulae and safracin (SAC) in Pseudomonas fluorescens demonstrated that 3-hydroxy-S-methyl-O-methyltyrosine (3hSmOmTyr), a nonproteinogenic amino acid, is the precursor of the tetrahydroisoquinoline molecular core. In the biosynthetic gene cluster of SAC/SFM, sacD/sfmD encodes a protein with high homology to each other but no sequence similarity to other known enzymes; sacF/sfmM2 and sacG/sfmM3 encode methyltransferases for C-methylation and O-methylation; and sacE/sfinF encodes a small protein with significant sequence similarity to the MbtH-like proteins, which are frequently found in the biosynthetic pathways of non ribosomal peptide antibiotics and siderophores. To address their function, the biosynthetic cassette of 3h5mOmTyr was heterologously expressed in S. coelicolor and P. putida, and an in-frame deletion and complementation in trans were carried out. The results revealed that (i) SfmD catalyzes the hydroxylation of aromatic rings; (ii) sacD/sacF/sacG in the SAC gene cluster and sfmD/sfmM2/sfmM3 in the SFM cluster are sufficient for the biosynthesis of 3h5mOmTyr; and (iii) the mbtH-like gene is not required for the biosynthesis of the 3h5mOmTyr precursor.

• BMB Reports
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• v.44 no.11
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• pp.725-729
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• 2011

We report a novel mechanism of a CDH1 splicing mutation in a patient with signet ring cell carcinoma of the stomach. A 27-year-old man complaining of aggravated dyspepsia was diagnosed with signet ring cell carcinoma. Both his father and uncle had died of stomach cancer at a young age. DNA sequencing analysis of the CDH1 gene revealed a splice site mutation (c.833-2A>G). By RNA/cDNA sequencing analysis, CDH1 c.833-2A>G generated a new acceptor site within intron 6, causing the insertion of a 79-bp intronic sequence between exon 6 and 7 (r.833-79_833-1ins), and resulting in a frame shift. E-cadherin immunohistochemical staining revealed a loss of CDH1 expression. This study reveals the disease-causing mechanism of this splicing mutation, and emphasizes the need for functional studies using RNA samples for the accurate interpretation of detected splicing variant. This is the first reported case of a CDH1 mutation in a Korean patient.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.11-11
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• 2010

The Korean ginseng, Panax ginseng C. A. Meyer is a popular medicinal herb in Araliaceae. Genetic map in crops provides valuable information for breeding, genetic and genomic researches. However, little information is available for construction of genetic map in ginseng. Up to now, we have produced large amounts of expressed sequence tags (ESTs) from four ginseng cultivars (37Mb, 49Mb, 39Mb, 47Mb from Gopoong, Gumpoong, Chunpoong and Yunpoong respectively using pyrosequencing technique and 5Mb from normalized full-length cDNA library of Chunpoong) to obtain comprehensive information of gene expression, and constructed EST database including ESTs from public database. Till now, we designed 261 SSR primer sets using EST sequences and identified 106 intergenic polymorphic markers. And 44 of the 106 showed polymorphisms among panax ginseng cultivars. Among 44 markers, 27 SSR polymorphic markers were inspected to 51 $F_2$ population from Yunpoong x Chunpoong, which showed good at the fitness of Mendellian segregation ratio 1:2:1. To enrich the number of markers, and thus construct high resolution genetic map which can be used as frame map for further genome sequencing. we are planning to develop large scale EST-derived SNP markers which are available in the F2 population. This study provides genetic information as well as foundation for ginseng researches such as genetics, genomics, breeding, and the final goal for whole genome sequencing. This study was supported by Technology Development Program for Agriculture and Forestry, Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea (Grant No. 609001-051SB210).

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.125-128
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• 2005

This paper illustrates potential applications of POM/OPM/BOR, which are used for deterministic reliability evaluation in the operation mode (operational planning and operating) in Korea Power System. Deterministic reliability evaluation in this paper bases the philosophy of the marginality and the limitation of physical quantity (voltage and thermal in main) under contingency analysis. The POM/OPM/BOR tools have been developed by V&R (Vaimann and Research) in USA. Before case studies, main frame and feature of the tools are introduced in brief. Case studies of the actual power system of Korea are demonstrated for checking the application possibility of POM/OPM/BOR.

• Reproductive and Developmental Biology
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• v.32 no.4
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• pp.223-227
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• 2008

Human embryonic stem (ES) cells retain the capacity for self-renewal, are pluripotent and differentiate into the three embryonic germ layer cells. The regulatory transcription factors Oct4, Nanog and Sox2 play an important role in maintaining the pluripotency of human ES cells. The aim of this research was to identify unknown genes upregulated in human ES cells along with Oct4, Nanog, and Sox2. This study characterizes an unknown gene, named chromosome 1 open reading frame 31 (C1orf31) mapping to chromosome 1q42.2. The product of C1orf31 is the hypothetical protein LOC388753 having a cytochrome c oxidase subunit VIb (COX6b) motif. In order to compare expression levels of C1orf31 in human ES cells, human embryoid body cells, vascular angiogenic progenitor cells (VAPCs), cord-blood endothelial progenitor cells (CB-EPCs) and somatic cell lines, we performed RT-PCR analysis. Interestingly, C1orf31 was highly expressed in human ES cells, cancer cell lines and SV40-immortalized cells. It has a similar expression pattern to the Oct4 gene in human ES cells and cancer cells. Also, the expression level of C1orf31 was shown to be upregulated in the S phase and early G2 phase of synchronized HeLa cells, leading us to purpose that it may be involved in the S/G2 transition process. For these reasons, we assume that C1orf31 may play a role in on differentiation of human ES cells and carcinogenesis.

• Journal of Ginseng Research
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• v.33 no.3
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• pp.212-218
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• 2009

Triterpenoid saponins were synthesized in Panax ginseng C.A. Meyer via the isoprenoid pathway by cyclization of 2,3-oxidosqualene to give primarily oleanane (beta-amyrin) or dammarane triterpenoid skeletons. The triterpenoids are backbone and undergoes various modifications (oxidation, substitution and glycosylation), mediated by cytochrome P450 (CYP)-dependent monooxygenases, glycosyltransferase and other enzymes. This is likely to be due in part to the complexity of the molecules and the lack of pathway intermediates for biochemical studies. A cDNA clone encoding a putative CYP gene was isolated from flower bud of ginseng and transformed into the plant(Nicotiana tabacum cv. Xanthi) and confirmed by PCR analysis. The CYP gene (PgCYP) contained an open reading frame(ORF) encoding mature protein of 500 amino acids. The expression of PgCYP were investigated in transgenic tobacco by reverse transcriptase-polymerase chain reaction (RT-PCR).

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.767-771
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• 2005

Expression in yeast may prove more amenable to generating large amounts of viral antigens for a vaccine candidate. We, therefore, cloned the gene encoding the Hepatitis C virus (HCV) structural proteins (C-El-E2, c740) fused in-frame with, and immediately 3' to, the chicken-lysozyme signal peptide (C-SIG) gene and under the control of the yeast glyceraldehyde-3-phosphate dehydrogenase gene promoter. In yeast, the HCV structural proteins were expressed in two different forms: a processed and a nonprocessed aggregated form. Biophysical characterization by sucrose linear gradient centrifugation revealed that both forms were present in the same fractions with a buoyant density of 1.127-1.176 g/$cm^3$. These findings suggest that the efficient synthesis of HCV structural proteins in yeast may be an important tool to study virus assembly and may lead to the development of an HCV vaccine.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.354-361
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• 2005

Vibrio fluvialis, an enteropathogenic bacterium, produces a phospholipase which is thought to be an important factor in the pathogenesis of disease. In this study, the phospholipase gene (vfp) was identified from V fluvialis (KCTC 2473) and its sequence was determined. The entire open reading frame was composed of 1,689 nuc1eotides and 563 amino acids. The phospholipase gene (vfp) was overexpressed in Escherichia coli as a his-tag fused protein. This recombinant protein (rVFP58) was solubilized with 6 M urea and purified by Ni-NTA affinity chromatography. The action mode of rVFP58 was determined by TLC and GC-MS, and it showed phospholipase B activity, which had both phospholipase A and lysophospholipase activities. The rVFP58 showed a maximum activity at pH around 9- 10 and temperature of about 40OC, and it was stable under alkaline condition over pH 9. The cytotoxicity of rVFP58 was evaluated, using a fish cell line, CHSE-2l4, and was found to cause significant cell death after 14 h of exposure to 250 $\mu$g of the protein.