Surveillance of avian influenza virus in wild bird fecal samples from South Korea, 2003-2008.

Kang, H M,Jeong, O M,Kim, M C,Kwon, J S,Paek, M R,Choi, J G,Lee, E K,Kim, Y J,Kwon, J H,Lee, Y J [Wildlife Disease Association] 2010 JOURNAL OF WILDLIFE DISEASES Vol.46 No.3

<P>We analyzed the results from nationwide surveillance of avian influenza (AI) from birds in South Korea's major wild bird habitats and the demilitarized zone of South Korea, 2003-2008. Of 28,214 fecal samples analyzed, 225 yielded influenza viruses, for a prevalence of 0.8%. Hemagglutinin (HA) subtypes H1-H12 and all nine neuraminidase (NA) subtypes were detected. The dominant HA subtypes were H6, H1, and H4, and the most common NA subtypes were N2, N1, and N6. Among the 38 HA/NA subtype combinations, the most common were H4N6, H6N1, and H5N2. Thirty-seven low-pathogenic AI (LPAI) viruses of the H5 and H7 subtype were detected. Among them, we identified bird species for 16 H5- and H7-positive fecal samples using a DNA bar-coding system instituted in 2007; all birds were identified as Anseriformes. The HA gene of the H5 wild bird isolates belonged to the Eurasian avian lineage, and could be clearly distinguished from the sublineage H5N1 highly pathogenic AI (HPAI) of the Eurasian and American avian lineages. Whereas H7 LPAI viruses did not group as a separate sublineage with H7 HPAI viruses, H7 isolates were closely related with the Eurasian avian lineage.</P>

Pathogenicity and transmission studies of H7N7 avian influenza virus isolated from feces of magpie origin in chickens and magpie

Kim, M.C.,Jeong, O.M.,Kang, H.M.,Paek, M.R.,Kwon, J.S.,Song, C.S.,Kwon, Y.K.,Lee, J.G.,Kwon, J.H.,Lee, Y.J. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.141 No.3

An H7N7 avian influenza virus [A/Magpie/Kr/YJD174/07 (H7N7); Mp/Kr/07 virus] was isolated from magpie feces in the north-western area (Youngjongdo) of South Korea and identified as low pathogenicity by intravenous pathogenic index and amino acid sequence of cleavage site. In genetic analysis, the genome of the Mp/Kr/07 virus was the same as those of two other H7N7 viruses isolated from the Mallard ducks in Ganghwa, 5km north of Youngjongdo, and grouped under the H7-subtype Eurasian linage with the highest similarity to recent two domestic duck isolates in South Korea. In vivo studies of the chickens and magpies, the Mp/Kr/07 virus, though did not caused any clinical signs with histological changes, could replicate in the oropharynx and cloaca of the chickens and was efficiently transmitted to contact chickens. However, the virus was restrictively identified in oropharynx of the magpies and was not spread to magpies by direct contact. These results suggest that magpie are not a biological amplifier of influenza virus and thus play a minimal role in virus transmission as intermediate host.

H₂O₂/HCl 처리한 Ti 임플란트의 생체활성 평가

유재선,권오성,이오연,이민호,송기홍,Yue J. S.,Kwon O. S.,Lee O. Y.,Lee M. H.,Song K. H. 한국재료학회 2005 한국재료학회지 Vol.15 No.5

Surface treatment play an important role in nucleating calcium phosphate deposition on surgical Ti implant. Therefore, the purpose of this study is to examine whether the precipitation of apatite on cp-Ti and Ti alloys are affected by surface modification in HCl and $H_2O_2$ solution. Specimens were then chemically treated with a solution containing 0.1 M HCl and 8.8M $H_2O_2$ at $80^{\circ}C$ for 30 mins, and subsequently heat-treated at $400^{\circ}C$ for 1 hour. All specimens were immersed in the HBSS with pH 7.4 at $36.5^{\circ}C$ for 15 days, and the surface was examined with XRD, SEM, EDX ana XPS. Also, pure Ti, Ti-6Al-4V and Ti-6Al-7Nb alloy specimens with and without surface treatment were implanted in the abdominal connective tissue of mice for 4 weeks. All specimens chemically treated with HCl and $H_2O_2$ solution have the ability to form a apatite layer in the HBSS which has inorganic ion composition similar to human blood plasma. The average thickness of the fibrous capsule surrounding the specimens implanted in the connective tissue was $38.57\;{\mu}m,\;62.27\;{\mu}m\;and\;45.64\;{\mu}m$ in the cp-Ti, Ti-6Al-4V ana Ti-6Al-7Nb alloy specimens with the chemical treatment respectively, and $52.20\;{\mu}m,\;75.62\;{\mu}m\;and\;66.56\;{\mu}m$ in the commercial specimens of cp-Ti, Ti-6Al-4V and Ti-6Al-7Nb without any treatment respectively. The results of this evaluation indicate that the chemically treated cp-Ti, Ti-6Al-4V ana Ti-6Al-7Nb alloys have better bioactivity and biocompatibility compared to the other metals tested.

O-GlcNAcylation of amyloid-β precursor protein at threonine 576 residue regulates trafficking and processing

Chun, Y.S.,Kwon, O.H.,Chung, S. Academic Press 2017 Biochemical and biophysical research communication Vol. No.

The pathological hallmark of Alzheimer's disease (AD) is associated with the accumulation of amyloid-β (Aβ) derived from proteolytic processing of amyloid-β precursor protein (APP). APP undergoes post-translational modification including N- and O-glycosylation. O-GlcNAcylation is a novel type of O-glycosylation, mediated by O-GlcNAc transferase attaching O-β-N-acetylglucosamine (O-GlcNAc) to serine/threonine residues of the target proteins. O-GlcNAc is removed by O-GlcNAcase. We have previously reported that increasing O-GlcNAcylated APP using the O-GlcNAcase inhibitor, PUGNAc, increases its trafficking rate to the plasma membrane and decreases its endocytosis rate, resulting in decreased Aβ production. However, O-GlcNAc modification sites in APP are unknown. In this study, we mutated three predicted O-GlcNAc modification threonine residues of APP into alanines (T291A, T292A, and T576A) and expressed them in HeLa cells. These APP mutants showed reduced O-GlcNAcylation levels, indicating that these sites were endogenously O-GlcNAcylated. Thr 576 was the major O-GlcNAcylation site when cell was treated with PUGNAc. We also showed that the effects of PUGNAc on APP trafficking to the plasma membrane and Aβ production were prevented in the T576A mutant. These results implicate Thr 576 as the major O-GlcNAcylation site in APP and indicate that O-GlcNAcylation of this residue regulates its trafficking and processing. Thus, specific O-GlcNAcylation of APP at Thr 576 may be a novel and promising drug target for AD therapeutics.

Simultaneous subtyping and pathotyping of the novel reassortant influenza A (H5N8) virus from clinical samples using a diagnostic microarray

Kwon, J. H.,Kim, J. H.,Lee, D. h.,Cho, H.,Hwang, S. Y.,Yuk, S. S.,Erdene-Ochir, T. O.,Noh, J. Y.,Hong, W. T.,Jeong, J. H. Springer Science + Business Media 2016 BioChip Journal Vol.10 No.3

<P>Highly pathogenic avian influenza (HPAI) viruses cause economic losses in the poultry industry and pose a severe threat to human health. Rapid and accurate diagnostic methods are important because they can help prevent further spread of the virus and reduce the time required for eradication of the virus. We developed a low-density microarray for the rapid detection and identification of avian influenza virus subtypes H5, H7, and H9 and their pathotypes in a previous study. In the present study, we report the development of updated probe sets and evaluation of the diagnostic microarray using H5N8 clade 2.3.4.4 HPAI viruses including clinical samples, without the need for egg propagation. Cy3-labeled DNA targets were obtained by reverse transcription polymerase chain reaction using Cy3-labeled universal primers, and labeled amplicons were hybridized to the microarray. All positive samples from RT-PCR showed H5-specific and highly pathogenic pattern in the microarray, without purification of PCR products. Furthermore, it allowed for specific detection of the subtype and pathotype from low DNA concentration samples that did not allow direct sequence analysis. Therefore, this diagnostic microarray has enormous potential for the rapid subtyping and pathotyping from clinical samples without the need for culture.</P>

An outbreak of highly pathogenic H5N1 avian influenza in Korea, 2008

Kim, H.R.,Park, C.K.,Lee, Y.J.,Woo, G.H.,Lee, K.K.,Oem, J.K.,Kim, S.H.,Jean, Y.H.,Bae, Y.C.,Yoon, S.S.,Roh, I.S.,Jeong, O.M.,Kim, H.Y.,Choi, J.S.,Byun, J.W.,Song, Y.K.,Kwon, J.H.,Joo, Y.S. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.141 No.3

In spite of intensive surveillance programs for the control of HPAI, an outbreak of highly pathogenic avian influenza (HPAI) H5N1 in Korea in April 2008 caused serious damage to poultry farms, as did previous outbreaks in 2003/2004 and 2006/2007. Six viruses were selected from the Korean 2008 isolates for genetic analysis, and all eight gene segments from each of the influenza viruses were sequenced. A phylogenetic analysis showed that all of the viruses were of the same virus type and that the hemagglutinin (HA) gene was clustered with that of clade 2.3.2 viruses. However, the internal and neuraminidase (NA) genes were closely related to those of the clade 2.3.4 viruses (recent human and bird isolates from Southeast Asia).

Cross-protective efficacies of highly-pathogenic avian influenza H5N1 vaccines against a recent H5N8 virus

Park, S.J.,Si, Y.J.,Kim, J.,Song, M.S.,Kim, S.m.,Kim, E.H.,Kwon, H.i.,Kim, Y.I.,Lee, O.J.,Shin, O.S.,Kim, C.J.,Shin, E.C.,Choi, Y.K. Academic Press 2016 Virology Vol.498 No.-

<P>To investigate cross-protective vaccine efficacy of highly-pathogenic avian influenza H5N1 viruses against a recent HPAI H5N8 virus, we immunized C57BL/6 mice and ferrets with three alum-adjuvanted inactivated whole H5N1 vaccines developed through reverse-genetics (Rg): [Vietnam/1194/04xPR8 (clade 1), Korea/W149/06xPR8 (clade 2.2), and Korea/ES223N/03xPR8 (clade 2.5)]. Although relatively low cross-reactivities (10-40 HI titer) were observed against heterologous H5N8 virus, immunized animals were 100% protected from challenge with the 20 mLD(50) of H5N8 virus, with the exception of mice vaccinated with 3.5 mu g of Rg Vietnam/1194/04xPR8. Of note, the Rg Korea/ES223N/03xPR8 vaccine provided not only effective protection, but also markedly inhibited viral replication in the lungs and nasal swabs of vaccine recipients within five days of HPAI H5N8 virus challenge. Further, we demonstrated that antibody-dependent cell-mediated cytotoxicity (ADCC) of an antibody-coated target cell by cytotoxic effector cells also plays a role in the heterologous protection of H5N1 vaccines against H5N8 challenge. (C) 2016 Elsevier Inc. All rights reserved.</P>

Validation of egg yolk antibody based C-ELISA for avian influenza surveillance in breeder duck

Jeong, O.M.,Kim, M.C.,Kang, H.M.,Ha, G.W.,Oh, J.S.,Yoo, J.E.,Park, C.H.,Kwon, J.S.,Pack, M.R.,Kim, H.R.,Kim, Y.J.,Kwon, J.H.,Lee, Y.J. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.144 No.3

Active surveillance for avian influenza virus (AIV) has expanded from chicken to various poultry species including duck. To further effective antibody screening in laying breeder ducks, we validated the egg yolk antibody as alternative source to serum for AIV antibody. Sera and eggs were collected at weekly intervals after two types of AIV vaccination, H5N3 and H9N2. The antibody levels were determined by an agar gel immunodiffusion (AGID) test, haemagglutination inhibition (HI) test and the competitive enzyme-linked immunosorbent assay (C-ELISA). AGID test did not detect antibodies in egg yolk, and the agreement between AGID test and either HI test or C-ELISA in serum was slight and fair based on kappa statistics (kappa value (κ)@?0.19 in H5N3 group and κ@?0.37 in H9N2 groups). However, there was almost perfect agreement between HI test and C-ELISA (κ>0.9 in all group). The C-ELISA was as sensitive and specific as the HI test, and could be used as a pre-screening test for the detection of type A avian influenza virus antibody. Comparison was made between egg yolk and serum antibody titers by a regression analysis. A high correlation was observed between serum and yolk antibody titers (r=0.8762 for H5N3 and 0.8914 for H9N2 in HI test; r=1 for H5N3 and 0.9686 for H9N2 in ELISA test), although egg yolk antibodies were detected later and remained lower levels than serum antibodies. In field trials involving 54 duck flocks, the positive rate of egg yolk and serum samples showed agreement for the detection of AIV antibody. We concluded that as an alternative to serum, antibody monitoring of laying breeder duck using egg yolk with C-ELISA is feasible and is recommended.

Infrared radiation modeling of NO, OH, CO, H₂O, and CO₂ for emissivity/radiance prediction at high temperature

Nam, H.J.,Kwon, O.J. Pergamon 2014 Infrared physics & technology Vol.67 No.-

In the present study, infrared radiation modeling of NO, OH, CO, H<SUB>2</SUB>O, and CO<SUB>2</SUB> molecules was devised based on a line-by-line method by utilizing a structured radiation analysis package, SPRADIAN07, coupled with up-to-date spectroscopic parameters and recent high-resolution radiation databases. An infrared calculation module was newly implemented in SPRADIAN07 for simulating the emissivity/radiance of NO and OH. The line positions of NO and OH molecules were determined by diagonalizing the Hamiltonian matrices of each molecule. The Einstein coefficients were obtained from either radiation databases or available calculated temperature-related line intensities. H<SUB>2</SUB>O, CO<SUB>2</SUB>, and CO were also modeled based on the high-resolution radiation databases, HITEMP2010 and CDSD-4000. When the line-by-line calculations were performed using the radiation databases, a parallel computing technique based on PC clusters was adopted for fast and efficient evaluation. The line-by-line model devised in the present study was validated by comparing the results with existing measurements. The simulations with room air absorption composed of H<SUB>2</SUB>O and CO<SUB>2</SUB> were also carried out. The spectra taken from a plasma torch and those from a rocket plume were calculated by utilizing the present radiation model. It was shown that the calculated spectra are in good agreement with observed ones.

CHF₃ / C₂F6 플라즈마에 의한 실리콘 표면 잔류막의 특성

권광호(K.-H. Kwon),박형호(H.-H. Park),이수민(S. M. Lee),강성준(S. J. Kang),권오준(O.-J. Kwon),김보우(B.W. Kim),성영권(Y.-K. Sung) 한국진공학회(ASCT) 1992 Applied Science and Convergence Technology Vol.1 No.1

실리콘을 CHF₃/C₂F_6 가스 플라즈마를 이용하여 식각하면 실리콘위에 탄소, 불소 및 산소로 이루어진 잔류막이 형성된다. 이 잔류막을 XPS로 분석한 결과 탄소는 C-Si, C-Si, C-C/H, C-CF_x(x≤3), C-F, C-F₂, C-F₃ 결합을 하고 있으며, 불소는 F-Si, F-C 및 F-O 결합으로 이루어져 있음을 알았다. 한편 산소는 O-Si 및 O-F 결합으로, 실리콘은 Si-Si, Si-C 및 Si-O 결합상태를 나타낸다. 잔류막의 수직분포 연구를 통하여 Si-O 및 Si-C 결합이 탄소와 불소의 결합층 아래에 존재하고, 잔류막의 표면부에 F-O 결합이 분포함을 알았다. 또한 건식식각 변수가 잔류막 형성에 미치는 영향이 조사되었으며 CHF₃/C₂F_6 가스 유량비, RF power 벚 압력 등이 잔류막의 두께, 조성비 및 잔류막의 결합상태에 영향을 미침을 알 수 있었다. Si surfaces exposed to CHF₃/C₂F_6 gas plasmas in reactive ion etching (RIE) have been characterized by X-ray photoelectron spectroscopy (XPS). CHF₃/C₂F_6 gas plasma exposure of Si surface leads to the deposition of residual film containing carbon and fluorine. The narrow scan spectra of C 1s show various bonding states of carbon as C-Si, C-Si, C-C/H, C-CF_x(x≤3), C-F, C-F₂, and C-F₃. The chemical bonding states of fluorine are described with F-Si, F-C, and F-O. And the oxygen and silicon are also detected. The effects of parameters for reactive ion etching as CHF₃/C₂F_6 gas ratio, RF power, and pressure are investigated.