Rapid and label-free bioanalytical method of alpha fetoprotein detection using LSPR chip

Kim, D.,Kim, J.,Kwak, C.H.,Heo, N.S.,Oh, S.Y.,Lee, H.,Lee, G.W.,Vilian, A.T.E.,Han, Y.K.,Kim, W.S.,Kim, G.b.,Kwon, S.,Huh, Y.S. North-Holland Pub. Co 2017 Journal of crystal growth Vol.469 No.-

Alpha fetoprotein (AFP) is a cancer marker, particularly for hepatocellular carcinoma. Normal levels of AFP are less than 20ng/mL; however, its levels can reach more than 400ng/mL in patients with HCC. Enzyme linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) have been employed for clinical diagnosis of AFP; however, these methods are time consuming and labor intensive. In this study, we developed a localized surface plasmon resonance (LSPR) based biosensor for simple and rapid detection of AFP. This biosensor consists of a UV-Vis spectrometer, a cuvette cell, and a biosensor chip nanopatterned with gold nanoparticles (AuNPs). In our LSPR biosensor, binding of AFP to the surface of the sensor chip led to an increasing magnitude of the LSPR signals, which was measured by an ultraviolet-visible (UV-Vis) spectrometer. Our LSPR biosensor showed sufficient detectability of AFP at concentrations of 1ng/mL to 1μg/mL. Moreover, the overall procedure for detection of AFP was completed within 20min. This biosensor could also be utilized for a point of care test (POCT) by employing a portable UV-Vis spectrometer. Owing to the simplicity and rapidity of the detection process, our LSPR biosensor is expected to replace traditional diagnostic methods for the early detection of diseases.

Characterization of a family B DNA polymerase from Thermococcus barophilus Ch5 and its application for long and accurate PCR

Kwon, K.M.,Kang, S.G.,Sokolova, T.G.,Cho, S.S.,Kim, Y.J.,Kim, C.H.,Kwon, S.T. IPC Science and Technology Press ; Elsevier Scienc 2016 Enzyme and microbial technology Vol.86 No.-

<P>The family B DNA polymerase gene from the euryarchaeon Thermococcus barophilus Ch5 (Tba5) contains an open reading frame of 6198 base pairs that encodes 2065 amino acid residues. The gene is split by three inteins that must be spliced out to form the mature DNA polymerase. A Tba5 DNA polymerase gene without inteins (genetically intein-spliced) was expressed under the control of the pET-28b(+)T7lac promoter in E. coli Rosetta 2(DE3)pLysS cells. The molecular mass of the purified Tba5 DNA polymerase was about 90 kDa consistent with the 90,470 Da molecular mass calculated based on the 776 amino acid sequence. The optimal pH for Tba5 DNA polymerase activity was 7.5 and the optimal temperature was 70-75 degrees C. The enzyme possessed 3' -> 5' exonuclease activity and was activated by magnesium ions. PCR amplification using Tba5 DNA polymerase enables high-yield for 1- to 6-kb target DNA products, while 8- to 10-kb target DNA products were amplified at low or inefficient levels. To simultaneously improve product yield and amplification fidelity, Tba5 plus DNA polymerase mixtures were constituted with various amounts of Tba5 DNA polymerase mixed with Taq DNA polymerase. The Tba5 plus DNA polymerase mixtures robustly amplified up to 25-kb lambda DNA fragments. In addition, the PCR error rate of Tba5 plus3 and Tba5 plus4 mixtures were much lower than those of wild-type Tba5 DNA polymerase, Pfu DNA polymerase, Taq DNA polymerase, and Pfu plus DNA polymerase. (C) 2016 Elsevier Inc. All rights reserved.</P>

Fully international system of units-traceable glycated hemoglobin quantification using two stages of isotope-dilution high-performance liquid chromatography-tandem mass spectrometry

Tran, T.T.H.,Lim, J.,Kim, J.,Kwon, H.J.,Kwon, G.C.,Jeong, J.S. Elsevier 2017 Journal of chromatography Vol.1513 No.-

<P>Glycated hemoglobin (HbA(1c)), defined as hemoglobin (Hb) molecules having a stable adduct of glucose on the N-terminal of the beta-chains, has been endorsed as a diagnostic tool for diabetes mellitus and a prediction indicator for the development of diabetes complications. Here we describe an accurate procedure using two stages of isotope dilution-ultra performance liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) for the quantification of HbA(1c) that provides full traceability to International System of Units (SI). First, synthetic peptides representing specific markers of HbA(1c) (G-hexa) and hemoglobin A(0) (Hexa) were certified by amino acid analysis via acid hydrolysis as reference materials (RMs) for the next step. For this peptide certification, three amino acids (proline, valine, and leucine) were determined by hydrolysis with 10 M hydrochloric acid at 130 degrees C for 48 h followed by ID-LC-MS/MS. Then, HbA(1c), content in blood was quantified with the ratio of specific proteolytic peptides from HbA(1c) and HbA(0) via enzyme digestion using ID-LC-MS/MS with the certified peptides as RMs and isotope-labeled peptides as internal standards. Results demonstrate complete traceability to SI-units throughout this procedure. Reliability was confirmed through comparative studies with commercially available RMs for HbA(1c), and other routine HbA(1c) diagnostic methods as well. Following full method validation, we applied this procedure to the certification of candidate hemolysate-certified RMs for HbA(1c) content, as well as 52 real clinical samples. All of the results showed the suitability of this method to act as a primary reference measurement procedure for HbA(1c) in complex biological samples. (C) 2017 Elsevier B.V. All rights reserved.</P>

농촌지역 수질개선을 위한 인공습지실험시설의 3 년간 실험결과 검토

윤춘경(C . G . Yoon),권순국(S . K . Kwun),우선호(S . H . Woo),권태영(T . Y . Kwon) 한국물환경학회 1999 한국물환경학회지 Vol.15 No.4

Sewage treatment study was performed for three years by constructed wetland experimental system at Konkuk University. The system was a subsurface flow type, and consisted of 60㎝ depth of sand and reeds. It worked continuously including winter time, and the sewage flowed without freezing even when average daily air temperature was below -10℃. Average removal rates of BOD, COD, and SS were in the range of 60∼71%, T-P removal rate was about 50%, and T-N removal rate was 24.3%. The reason for poor T-N removal might be due to high influent concentration and shorter retention times. The effluent of the wetland system often exceeded effluent water quality standards for sewage treatment plant, therefore, further treatment could be required if the effluent needs be discharged to the public water. Wetland system involves relatively large land area and could be suitable for rural area rather than urban area. Therefore, utilization of sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal depending on site specific environmental conditions.

Seroprevalence of equine piroplasms in the Republic of Korea

Seo, M.G.,Yun, S.H.,Choi, S.K.,Cho, G.J.,Park, Y.S.,Kwon, O.D.,Cho, K.H.,Kim, T.H.,Jeong, K.S.,Park, S.J.,Kwon, Y.S.,Kwak, D. Elsevier Scientific Pub. Co 2011 Veterinary parasitology Vol.179 No.1

Equine piroplasms include two tick-borne protozoan parasites, Babesia caballi and Theileria equi. Although no clinical equine piroplasmosis has been reported in the Republic of Korea, the possible existence of the disease has been proposed due to a nationwide distribution of the vector ticks. To determine if the antibodies against B. caballi and T. equi were present, 184 sera of horses (Equus caballus) raised in the Republic of Korea from 2007 to 2010 were assessed using cELISA kits. Two (1.1%) out of 184 sera were positive for T. equi, but none were seropositive for B. caballi. Both samples tested positive came from one region (Gyeonggi province). The accuracy of the cELISA was confirmed by PCR using primers specific to the 18S rRNA of T. equi. This study presents for the first time horses infected by T. equi in the Republic of Korea. Since the infection of T. equi occurred in horses raised in the Republic of Korea, further studies with continuous monitoring of the vector ticks for equine piroplasms and appropriate control programs need to be established.

Influence of N-doping on the structural and photoluminescence properties of graphene oxide films

Van Khai, T.,Na, H.G.,Kwak, D.S.,Kwon, Y.J.,Ham, H.,Shim, K.B.,Kim, H.W. Pergamon Press ; Elsevier Science Ltd 2012 Carbon Vol.50 No.10

Nitrogen (N) was doped into graphene oxide (GO) films at temperatures of 600-900<SUP>o</SUP>C under the flow of a mixture of NH<SUB>3</SUB> and Ar. The N (atomic) concentration was varied in the range of 3.63-7.45%. XPS and FTIR spectra show that there are mainly single C-N and double C?N bonds in the GO sheet. Raman spectra indicate that the G band becomes closer to the position of the G band of graphite with increasing doping temperature, and thus reveal that N doping produces a blue-shift of the G-band. In room-temperature photoluminescence (PL) spectra, N-doping produces an increase not only in the overall PL intensity, but also in the wavelength of the peak maxima. The shift of the induced PL of N-doped graphene is attributed mainly to the increased number of graphitic (or quaternary) N.

Bioethanol Production Using Waste Seaweed Obtained from Gwangalli Beach, Busan, Korea by Co-culture of Yeasts with Adaptive Evolution

Sunwoo, I. Y.,Kwon, J. E.,Nguyen, T. H.,Ra, C. H.,Jeong, G. T.,Kim, S. K. Springer Science + Business Media 2017 Applied biochemistry and biotechnology Vol.183 No.3

<P>Conditions for ethanol production were evaluated using waste seaweed obtained from Gwangalli beach, Busan, Korea, after strong winds on January 15, 2015. Eleven types of seaweed were identified, and the proportions of red, brown, and green seaweed wastes were 26, 46, and 28%, respectively. Optimal pretreatment conditions were determined as 8% slurry content, 286 mM H2SO4 for 90 min at 121 A degrees C. Enzymatic saccharification with 16 units/mL Celluclast 1.5L and Viscozyme L mixture at 45 A degrees C for 48 h was carried out as optimal condition. A maximum monosaccharide concentration of 30.2 g/L was obtained and used to produce ethanol. Fermentation was performed with single or mixed yeasts of non-adapted and adapted Saccharomyces cerevisiae KCTC 1126 and Pichia angophorae KCTC 17574 to galactose and mannitol, respectively. The maximum ethanol concentration and yield of 13.5 g/L and Y-EtOH of 0.45 were obtained using co-culture of adapted S. cerevisiae and P. angophorae.</P>

The development of rapid real-time PCR detection system for <i>Vibrio parahaemolyticus</i> in raw oyster

Kim, J.S.,Lee, G.G.,Kim, J.,Kwon, J.Y.,Kwon, S.-T. Blackwell Publishing Ltd 2008 Letters in applied microbiology Vol.46 No.6

<P>Abstract</P><P>Aims: </P><P>To develop a new rapid real-time polymerase chain reaction (PCR) based detection system for <I>Vibrio parahaemolyticus</I> (<I>V. parahaemolyticus</I>) applicable to raw oyster samples.</P><P>Methods and Results: </P><P><I>V. parahaemolyticus</I> cells were artificially inoculated to oysters. Samples were homogenized in 100 ml of sterile saline water and serially diluted to 1·5 CFU ml<SUP>−1</SUP> level. One millilitre of diluents was centrifuged and the pellet was resuspended with 100 <I>&mgr;</I>l of de-ionized water. DNA was extracted by boiling for 20 min, and 0·5 <I>&mgr;</I>l was used as a template for PCR reaction. Real-time PCR was performed with TMC-1000 system (1 <I>&mgr;</I>l PCR system). The detection system was found to achieve detection limit of 1·5 CFU g<SUP>−1</SUP> for <I>V. parahaemolyticus</I>. Furthermore, the specificities of these assay systems were confirmed with more than 20 bacterial strains, including various <I>Vibrio</I> species.</P><P>Conclusions: </P><P>Rapid and sensitive food-borne pathogen detection techniques for <I>V. parahaemolyticus</I> is important to the food industry and consumers. The direct detection of <I>V. parahaemolyticus</I> from food is possible with micro real-time PCR system.</P><P>Significance and Impact of the Study: </P><P>This study shows that oyster samples can be tested for <I>V. parahaemolyticus</I> with a rapid, specific and simple procedure.</P>

Synthesis and biological evaluation of 2-phenol-4-chlorophenyl-6-aryl pyridines as topoisomerase II inhibitors and cytotoxic agents

Thapa, P.,Kadayat, T.M.,Park, S.,Shin, S.,Thapa Magar, T.B.,Bist, G.,Shrestha, A.,Na, Y.,Kwon, Y.,Lee, E.S. Academic Press ; Academic Press 2016 Bioorganic chemistry Vol.66 No.-

<P>A new series of 2-phenol-4-chlorophenyl-6-aryl pyridines were designed, synthesized, and evaluated for topoisomerase (topo) I and II inhibitory activities as well as cytotoxic activity against four different human cancer cell lines such as HCT15, T47D, DU145, and Hela. Most of the tested compounds exhibited stronger topo II inhibitory activity at 100 mu M as compared to etoposide. All the compounds, except 39, did not show topo I inhibitory activity. Interestingly, compounds that showed better topo II inhibition than etoposide have ortho-or para-chlorophenyl at 4-position of central pyridine, and none of the compounds possess meta-chlorophenyl. SAR study revealed the importance of ortho-or para-chlorophenyl at 4-position of the central pyridine for selective topo II inhibitory activity. Similarly, all compounds possessing meta-or para-hydroxyphenyl moieties showed moderate to significant cytotoxic effects. Particularly, compounds 27-37, and 39 which showed excellent cytotoxicity (IC50 = 0.68-1.25 mu M) against T47D breast cancer cells suggest the importance of meta-or para-hydroxyphenyl moiety at 2-position of the central pyridine for the design of anticancer agents with related scaffolds. (C) 2016 Elsevier Inc. All rights reserved.</P>

t-SNE 기법을 적용한 지중송전케이블 시스템 PD Pulse 분석

정연하(JUNG Y.H.),장태인(JANG T.I.),최민희(CHOI M.H.),이의찬(LEE E.C.),권대혁(Kwon D.H),양희석(YANG H.S),고재홍(GO J.H.),차상국(CHA S.K),황광모(HWANG G.M.),김숙주(KIM S.J.) 대한전기학회 2020 대한전기학회 학술대회 논문집 Vol.2020 No.7