• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.752-756
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• 2006

The independent anoxic reactor was introduced in biological aerated filters as the regulation of water quality requirement, especially total nitrogen, had been strengthened. The process studied in this work was upflow $Biobead^{(R)}$ process which was used commercial invented for removal of organic materials and nitrification. For the purpose of evaluating the independent anoxic reactor, PCR-DGGE, of the molecular biological methods, was performed. Two types of nitrite reductase genes were selected. One is nirS represented cytocrome $cd_1$ nitrite reductase gene and the other is nirK represented Cu-containing nitrite reductase gene. Denitrifier community in the independent anoxic reactor was analyzed with PCR-DGGE using these two denitrifying functional genes. As the result of the PCR, only nirS gene was detected between nirS and nirK. With the result of the DGGE, specific bands became strong, as the operating days were longer, nitrate loading rate was increased. otherwise those of the initial activated sludge showed various bands. In the consequence of the sequence of DGGE bands, various denitrifiers were sequenced in the initial activated sludge, while specific denitrifiers like alcaligenes faecalis were predominant in the anoxic reactor. Consequently, introduction of the independent anoxic reactor made it possible to achieve 96% denitrification efficiency, and was proper for the modification of BAF process.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.459-464
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• 2016

An outbreak of the migratory locust, Locusta migratoria, in the environment-friendly reclaimed plantations of forage crops in Sanyimyeon, Haenam-gun, Jellanam-do, Korea in August 2014 caused severe damages to various crops. Owing to its first occurrence in the Korean history, the causes underlying the outbreak and phase-transition of the migratory locust were not known. It is critical to establish the genetic relationship of the migratory locust in Sanyimyeon, Haenam-gun with the other previously reported strains in the world in order to understand the mechanisms responsible for its outbreak. The gene sequences of the 16S ribosomal RNA (rRNA) and displacement-loop (D-loop) of the mitochondria of various regional species of the migratory locust were used to perform the phylogenetic analysis. Our results suggested that the migratory locusts in Sanyimyeon, Haenam-gun are closely related with the Eurasian strains of the northern lineage. In future, these two mitochondrial genes can be used for elucidating the genetic population structures in migratory locusts in various regions. In addition, the sequence information of these genes can be used to enhance our understanding of the genetic basis of the outbreak of migratory locusts.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1199-1206
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• 2006

Plasminogen kringle 5 is a potent inhibitor of endothelial tell proliferation like an endogenous angiogenesis inhibitor, angiostatin consisting of plasminogen kringles 1-4. In this study, we produced the recombinant protein of plasminogen kringle 5 (PK5) employing an Pichia expression system and examined its. effect on~endothelial cell migration and its possible inhibitory mechanism. PK5 was expressed in Pichia pastoris GS115 by fusion of the cDNA spanning from Thr456 to Phe546 to the secretion signal sequence of a-factor prepro-peptide. After methanol induction, the secreted PK5 was purified by using S-spin column. SDS-PACE analysis of the purified protein showed one major band of approximately 10kDa. In in vitro migration assays, the purified protein inhibited dose-dependently the migration of human umbilical endothelial cells (HUVECs) induced by basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) with an $IC_{50}$ of approximately 500nM. Accordingly, it inhibited bfGF-stimulated extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in HUVECs at 500nM. In addition, it also potently inhibited bFGF-induced cytoskeletal rearrangement of HUVECs. Thus, these results suggest that Pichia-produced PK5 effectively inhibits endothelial cell migration, in part by suppression of ERK1/2 activation and blocking cytoskeleton rearrangement.

• Journal of Life Science
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• v.21 no.1
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• pp.96-101
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• 2011

S-Adenosyl-L-methionine synthtase (SAM-s) catalyzes the biosynthesis of SAM from ATP and L-methionine. SAM plays important roles in the primary and secondary metabolism of cells. A metK encoding a SAM-s was searched from Streptomyces natalensis producing natamycin, a predominantly a strong antifungal agent, inhibiting the growth of both yeasts and molds and preventing the formation of aflatoxin in filamentous fungi. To obtain the metK of S. natalensis, PCR using primers designed from the two highly conserved regions for metK genes of Streptomyces strains was carried out, and an intact 1.2-kb metK gene of S. natalensis was cloned by genomic Southern hybridization with PCR product as a probe. To identify the function of the cloned metK gene, it was inserted into pSET152ET for its high expression in the Streptomyces strain, and then introduced into S. lividans TK24 as a host by transconjugation using E. coli ET12567(pUZ8002). The high expression of metK in S. lividans TK24 induced actinorhodin production on R5 solid medium, and its amount in R4 liquid medium was 10-fold higher than that by exconjugant including only pSET152ET.

• Journal of Life Science
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• v.24 no.9
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• pp.995-1000
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• 2014

The studies of marine viruses in terms of viral isolation and detection have been limited due to the high mutation rate and genetic diversity of marine viruses. Of the modern methods currently used to detect marine viruses, serological methods based on enzyme-linked immunosorbent assay (ELISA) are the most common. They depend largely on the quality of the antibodies and on highly purified suitable antigens. Recently, a new experimental system for using viral capsid protein as an antigen has been developed using the yeast surface display (YSD) technique. In the present study, the capsid protein gene of the red-spotted grouper nervous necrosis virus (RGNNV) was expressed and purified via YSD and HA-tagging systems, respectively. Two regions of the RGNNV capsid protein gene, RGNNV1 and RGNNV2, were individually synthesized and subcloned into a yeast expression vector, pCTCON. The expressions of each RGNNV capsid protein in the Saccharomyces cerevisiae strain EBY100 were indirectly detected by flow cytometry with fluorescently labeled antibodies, while recognizing the C-terminal c-myc tags encoded by the display vector. The expressed RGNNV capsid proteins were isolated from the yeast surface through the cleavage of the disulfide bond between the Aga1 and Aga2 proteins after ${\beta}$-mercaptoethanol treatment, and they were directly detected by Western blot using anti-HA antibody. These results indicated that YSD and HA-tagging systems could be applicable to the expressions and purification of recombinant RGNNV capsid proteins.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.1-8
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• 2017

Measles virus is a highly contagious, exanthematic virus, preventable by the use of an effective live-attenuated vaccine. However, measles virus remains endemic in many area of the world causing nearly 200,000 deaths per year and still a major cause of child mortality, mostly in developing countries. In March 2014, Republic of Korea was certified as a 'national measles elimination' by the WHO as a result of a high-quality case-based surveillance system and population immunity, which was achieved by a high vaccination rate (>95.0% since 1996). But, since the beginning of 2014, the Gyeonggi province has experienced a resurgence of measles cases. In this study, we investigated the characteristics of measles viruses isolated from confirmed measles in Gyeonggi province during January 1, 2014 ~ July 31, 2014, 60 isolates were obtained from 72 confirmed measles specimens. Genotypic distributions and genetic diversities of isolated measles virus were analyzed by sequencing of nucleoprotein (N) gene. 58 (96.7%) imported cases were identified. The predominant genotype was B3, which reflects the circulating measles virus in adjacent countries. The sequences of nucleoprotein (N) gene of isolated MeV were showed that the strains characterized showed the highest degree of identity (99%) with the Philippine related strains in 2013-2014. Therefore, infected traveler returning from the Philippines transmitted secondary infection in Korea.

• KSBB Journal
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• v.21 no.2
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• pp.90-95
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• 2006

Escherichia coli harboring pAC-LYCO4 and pDdxs was used for lycopene production. Three wild type strains of E. coli OW1, MG1655, and W3110 were compared with DH5${\alpha}$ used before for lycopene production. Lycopene productivity of E. coli MG1655 was similar to DH5${\alpha}$ and the highest among those wild type strain. Therefore, MG1655 strain was used for random transposon and NTG mutagenesis to increase lycopene productivity. Through transposon mutation, five transposon mutants with increased lycopene productivity were obtained. It was found that genes knocked out by transposon insertion were treB in Tn1 mutant, B2436 in Tn2 mutant, and rfaH in Tn3, 4, and 5 mutants. Lycopene productivity was the highest in Tn4 mutant among the Tn mutants, which was 6-fold and 8-fold higher in lycopene concentration and content, respectively, in comparison with those obtained with wild type strain. NTG4 mutant was acquired with NTG mutation. The highest lycopene productivity of 6 mg/L and 4 mg/g DCW was obtained from the NTG4 mutant when arabinose of 0.013 mM was added for induction of dxs, rate-limiting gene of MEP pathway. The lycopene productivity of NTG4 mutant was increased 18-fold and 12-fold in lycopene concentration and content, respectively when comparing with the wild type strain.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.2
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• pp.67-74
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• 2013

Approximate string matching problems have been studied in diverse fields. Recently, fast approximate string matching algorithms are being used to reduce the time and costs for the next generation sequencing. To measure the amounts of errors between two strings, we use a distance function such as the edit distance. Given two strings X(|X| = m) and Y(|Y| = n) over an alphabet ${\Sigma}$, the edit distance between X and Y is the minimum number of edit operations to convert X into Y. The edit distance between X and Y can be computed using the well-known dynamic programming technique in O(mn) time and space. The edit distance also can be computed using the Four-Russians' algorithm whose preprocessing step runs in $O((3{\mid}{\Sigma}{\mid})^{2t}t^2)$ time and $O((3{\mid}{\Sigma}{\mid})^{2t}t)$ space and the computation step runs in O(mn/t) time and O(mn) space where t represents the size of the block. In this paper, we present a parallelized version of the computation step of the Four-Russians' algorithm. Our algorithm computes the edit distance between X and Y in O(m+n) time using m/t threads. Then we implemented both the sequential version and our parallelized version of the Four-Russians' algorithm using CUDA to compare the execution times. When t = 1 and t = 2, our algorithm runs about 10 times and 3 times faster than the sequential algorithm, respectively.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.144-150
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• 2010

This study was aimed to screen bacteria of high alginate-degrading activity, to select the nitrogen source and concentration of NaCl and sodium alginate for the production of alginate-degrading enzyme, and to determine reaction conditions of enzyme. A novel alginate-degrading bacterium was isolated from abalone (Haliotis discus hannai) and named Methylobacterium sp. HJM27 by 16S rDNA sequence analysis. The optimum culture conditions for the production of alginate-degrading enzyme were 1.0% sodium alginate, 0.5% peptone, 0.3% yeast extract, 1.5% NaCl, $25^{\circ}C$ and 48 hours incubation time. The raw enzyme showed the highest activity at $25^{\circ}C$ and pH 9, and produced 1.217 g - reducing sugar per liter in 0.8% (w/v) sodium alginate for 30 minutes. Methylobacterium sp. HJM27 and its alginate-degrading enzyme would be useful for the production of bioenergy and biofunctional oligosaccharides from seaweed.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.224-231
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• 1995

To increase the expression of a foreign protein in transgenic plant, the benefits of 5'-untranslated leader sequences of tobacco mosaic virus (TMV) RNA or soybean glycinin gene, Gy2, fused to a protein coding sequence were exploited. pGA643-derived plasmid contains 355 promoter of cauliflower mosaic virus, protein coding sequence of maize 10 kDa zein (10kZ) and Gy2 terminator. The leader from Gy2 or TMV RNA was inserted between the promoter and the coding sequence in each construct. The recombinant DNAs were introduced into tobacco plants by Agrobacterium mediated leaf disc transformation method. Although the transgene without the leader had more transcripts than the others, mRNAs containing the leader were translated more efficiently. It might be due to difference in the length of 5'-untranslated sequence and context surrounding the AUG codon, but could be sequence specific rather. These results suggest that the leader sequences of Gy2 and TMV play important roles as an enhancer in translational control of foreign gene in transgenic tobacco plant.