• Parasites, Hosts and Diseases
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• v.52 no.2
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• pp.143-149
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• 2014

To evaluate the seroprevalence against circumsporozoite protein (CSP) of Plasmodium vivax in sera of Korean patients, the central repeating domain (CRD) of CSP was cloned and analyzed. From the genomic DNA of patient's blood, 2 kinds of CSPs were identified to belong to a VK210 type, which is the dominant repeating of GDRA(D/A)GQPA, and named as PvCSPA and PvCSPB. Recombinantly expressed his-tagged PvCSPA or PvCSPB in Escherichia coli reacted well against sera of patients in western blot, with the detecting rate of 47.9% (58/121), which included 15 cases positive for PvCSPA, 6 cases positive for PvCSPB, and 37 cases for both. The mixture of PvCSPA and PvCSPB was loaded to a rapid diagnostic test kit (RDT) and applied with the same set of patient sera, which resulted in detection rates of 57.0% (69/121). When the protein sequences of PvCSPA were compared with those of P. vivax in endemic regions of India and Uganda, they were compatibly homologous to PvCSPA with minor mutations. These results suggested that the recombinant PvCSPA and PvCSPB loaded RDT may be a milestone in latent diagnosis which has been a hot issue of domestic malaria and important for radical therapy in overlapped infections with P. falciparum in tropical and subtropical areas. During the biological process of malarial infection, exposure of CSP to antigen-antibody reaction up to 57.0% is the first report in Korea.

• Parasites, Hosts and Diseases
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• v.55 no.1
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• pp.9-13
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• 2017

Seroprevalence of Toxoplasma gondii infection among the residents of Seokmo-do (Island) in Ganghwa-gun, Incheon, Korea was surveyed for 4 years by a rapid diagnostic test (RDT) using recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A. Sera from 312, 343, 390, and 362 adult residents were collected on a yearly basis from 2010 to 2013, respectively. Total positive seroprevalence regardless of gender was 29.2, 35.3, 38.7, and 45.3% from 2010 to 2013, respectively. Positive seroprevalence in male adults was 43.9, 48.2, 45.4, and 55.3%, which was far higher than that of the corresponding female adults which was 20.7, 29.2, 33.9, and 38.9%, from 2010 to 2013, respectively. This high seroprevalence of toxoplasmosis in Seokmo-do may have been caused in part by peculiar changes in the toxoplasmic environment of the island as it is a relatively isolated area preserving its natural habitat while also being connected by a bridge to the mainland. Further study is necessary to find out symptomatic patients and to confirm the risk factors.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.706-712
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• 2012

The present study was aimed to produce a chicken polyclonal antibody against Cronobacter muytjensii and to develop an immunoassay for its detection. Purification of anti-C. muytjensii IgY from egg yolk was accomplished using various methods such as water dilution and salt precipitation. As a result, sodium dodecyl sulfate-polyacrylamide gel electrophoresis produced two bands around 30 and 66 kDa, corresponding to a light and a heavy chain, respectively. Indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) was performed to determine the effectiveness of the chicken IgY against C. muytjensii. The optimum conditions for detecting C. muytjensii by indirect ELISA and checkerboard titration of the antigen revealed an optimum average absorbance at the concentration of 18 ${\mu}g/mL$, having ca. $10^8$ coated cells per well. The anti-C. muytjensii IgY antibody had high specificity for C. muytjensii and low cross-reactivity with other tested pathogens. In this assay, no cross-reactivity was observed with the other genera of pathogenic bacteria including Escherichia coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, Bacillus cereus, Enterobacter aerogenes, Salmonella Enteritidis and Listeria monocytogenes. In addition, detection of C. muytjensii in infant formula powder showed a low matrix effect on the detection curve of IC-ELISA for C. muytjensii, with similar detection limit of $10^5$ CFU/mL as shown in standard curve. These findings demonstrate that the developed method is able to detect C. muytjensii in infant formula powder. Due to the stable antibody supply without sacrificing animals, this IgY can have wide applications for the rapid and accurate detection of C. muytjensii in dairy foods samples.

• Analytical Science and Technology
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• v.17 no.3
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• pp.211-216
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• 2004

Commercial one-step rapid fecal occult blood (FOB) kit which was used as a screening test to detect traces of blood in stool samples was evaluated for the feasibility of the forensic identification of human blood. The sensitivity was determined and compared with the conventional Leucomalichite green (LMG) method. In addition, the specificity of the kit and the effects of various chemicals and environmental factors were examined. FOB kit was specific for human hemoglobin and more sensitive than LMG test (approximately 100 times). FOB kit showed positive band using at least 1,000,000-fold diluted human blood. The antigen was very stable regardless of storage temperature and boiling. The positive reaction was not affected by LMG and Luminol, the traditional tests for identification of bloodstain. As a results, FOB test kit could be effectively applied to identification of human blood at crime scene and crime laboratories.

• Journal of Medicine and Life Science
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• v.17 no.1
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• pp.29-32
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• 2020

As respiratory syncytial virus(RSV) is transmitted either via directly contact with an infected case or via indirectly contaminated fomites or skin, the major preventive measures are strict hand hygiene, early detection of transmitted sources, and rapid isolation of RSV patients. Especially early detection of hidden cases is the most critical control measure when an index case was notified in a postpartum center. The Guideline of Korea Centers for Diseases Control and Prevention defines potential contacts in an epidemiologic survey as admitted newborns, parents of index cases, center's workers, and visitors for 10 days before the first diagnosis day of index case. However, it needs to classify potential contacts in more detail in order to conduct a successful survey. Authors conducted to search related literatures and appraise the evidences. Firstly, potential contacts would be classified into RSV-related symptomatic contacts(SxC) and asymptomatic contacts. And then, mother, caring workers, and visitors of the index cases among asymptomatic contacts would be defined as the asymptomatic close contacts(ASCC). Finally, the rest would be defined as the asymptomatic regular contacts(ASRC). The defined test using reverse transcription-PCR is applied to SxC and ASCC, and decision of isolation or regular activities are made according to the results. The rapid antigen detection test kits are applied to ASRC. These suggestions might be helpful to detect hidden cases earlier and prevent a further infection.

• Annals of Laboratory Medicine
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• v.39 no.1
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• pp.50-57
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• 2019

Background: The Automated Fluorescent Immunoassay System (AFIAS) rotavirus assay (Boditech Med Inc., Chuncheon, Korea) is a new rapid antigen test for rotavirus detection. We evaluated the performance of this assay for detecting rotaviruses and their specific genotypes in clinical stool samples. Methods: AFIAS rotavirus assay was performed in 103 rotavirus-positive and 103 rotavirus-negative stool samples (confirmed by both PCR and ELISA), and its results were compared with those of PCR, ELISA, and immunochromatographic assay (ICA). We evaluated diagnostic sensitivity/specificity, the detectability of rotavirus subtypes, lower limit of detection (LLOD), reproducibility, cross-reactivity, and interference of AFIAS rotavirus assay. Results: Based on PCR and ELISA results, diagnostic sensitivity and specificity of the AFIAS rotavirus assay were both 99.0%. LLOD results showed that the AFIAS assay had sensitivity similar to or greater than ICA and ELISA. High reproducibility was confirmed, and no cross-reactivity or interference was detected. This assay could detect genotypes G1P[8], G2P[4], G3P[8], G4P[6], G4P[8], G8P[4], G8P[8], G9P[4], and G9P[8]. Conclusions: The AFIAS rotavirus assay showed high reproducibility, sensitivity, and specificity as well as excellent agreement with ELISA, PCR, and ICA. It detected the most common as well as unusual genotypes of rotavirus prevalent in Korea. It could be a useful onsite assay for rapid, convenient, and cost-effective detection of rotavirus infection.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.223-224
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• 2015

구제역은 소, 돼지 등 발굽이 두 개로 갈라진 가축들에게 감염을 유발하는 전염성이 매우 높은 바이러스성 질병이다. 구제역 감염 시 입 주변, 구강 내, 코, 발굽사이 등에 수포가 생기며 고열과 식욕이 저하되어 심하게 앓거나 죽게 되는데, 강한 감염 전파력을 가졌음에도 치료제가 없고, 감염확인 즉시 확산 방지를 위한 살 처분만이 이루어지고 있다. 따라서 무엇보다도 빠른 감염여부 진단이 중요하다. 현재까지 구제역을 진단하는 방법으로는 감염 된 가축의 혈액에서 구제역 항원 단백질에 대한 항체형성 여부를 확인하는 항체진단법과 수포액과 같은 체액을 채취하여 세포배양을 통한 구제역 바이러스 분리방법이 있지만 두 가지 모두 짧은 잠복기를 갖는 구제역 바이러스를 빠른 시간 내 진단하기는 어렵다. 따라서 본 연구에서는 보다 빠른 구제역 진단 키트개발을 위해 NCBI Pubmed를 이용하여 구제역바이러스가 가지는 6개의 주요 단백질을 확인하였고, NCBI BLAST를 이용하여 6개의 단백질 중 구제역 바이러스에 특이적인 항원 단백질 peptidase C28을 선정하였다. 선정된 단백질의 아미노산 서열을 이용하여 IEDB analysis resource를 통해 peptidase C28의 epitope 부위를 예측하였다. 예측 된 부위의 아미노산 서열을 NCBI BLAST에서 정상 동물과 비교하여 구제역바이러스 특이 항원 단백질 epitope peptide를 최종 선정하였다. 이를 이용한 구제역 바이러스 진단키트 제작은 보다 빠른 진단을 통해 감염 확산을 조기에 차단하고 경제적 손실과 피해를 최소화 할 수 있다.

• Korean Journal of Veterinary Service
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• v.24 no.3
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• pp.255-262
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• 2001

Five pigs industry with outbreaks of transmissible gastroenteritis(TGE) in Gyeongbuk province were investigated during the period from January to December 2000. The typical signs of TGE in piglets had transient vomiting and a watery yellowish diarrhea, rapid loss of weight, dehydration and high mortality in pigs under 2 weeks of age. Clinical signs of TGE in growing and finishing pigs and sows were usually limited to inappetence and diarrhea for one or a few days, with vomiting observed in an occasional animal. The detection of TGE viral antigen in epithelial cells of the small intestine had been used in indirect fluorescent antibody test (IFA) for diagnosing TGE in young pigs. WかR had been successfully used to detect the DNA derived from TGEV in specimen of intestinal swabs. Among 5 pigs industry, four showed typical signs of epizootic TGE and one progressing enzootic TGE. It was 22～53 days that the duration of initial clinical disease in TGE outbreaks of pigs investigated in Gyeongbuk province in 2000. However the duration related directly to herd size. Mortality of piglets under 2 weeks of age for duration was 53.2～88.2%, but that of piglets 2～5 weeks of age was 2.5～6.5%. The piglets of 1 weeks of age died mostly during duration of TGE, but varied considerably with husbandry and other environmental factors.

• Rapid Communication in Photoscience
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• v.2 no.2
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• pp.46-51
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• 2013

This study reports a fiber-optic sensor detecting biomolecule by simultaneously monitoring localized surface plasmon resonance (LSPR) from gold nanoparticles (Au NPs) of ca. $50{\pm}5$ nm attached on one end of optical fiber and surface enhanced Raman scattering (SERS) of the reporter molecules adsorbed on the gold surfaces as an additional sensing tool. The sensor was fabricated by immobilizing Au NPs on one end of an optical fiber by chemical reaction. LSPR and SERS signals of the sensor were measured using various refractive indices solutions. Finally, the sensor was applied to observe real-time LSPR sensor-gram and SERS spectra of the reporter molecule of 4-aminothiphenol during the antibody-antigen reaction of interferon-gamma (IFN-${\gamma}$) as a proof-concept experiment of biological applications.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.544-549
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• 2014

Lily symptomless virus (LSV), Lily mottle virus (LMoV), and Cucumber mosaic virus (CMV) are the most prevalent viruses infecting lilies in Korea. Leaf and bulb samples showing characteristic symptoms of virus infection were collected in 2012, and 80 field samples were analyzed by reverse transcription polymerase chain reaction (RT-PCR). The infection frequencies were 79% for LMoV, 5% for LSV, and 3% for CMV. The LMoV coat protein gene was amplified and cloned into the pET21d(+) expression vector to develop serological diagnostic tools to detect LMoV. The resulting carboxy-terminal His-tagged coat proteins were expressed in Escherichia coli strain BL21 (DE3) by induction with IPTG. The recombinant proteins were purified using Ni-NTA agarose beads and used as an antigen to produce polyclonal antibodies in laying hens. The resulting egg yolk immunoglobulin (IgY) specifically recognized LMoV from infected plant tissues in immunoblotting assays and had comparable sensitivity to that of a mammalian antibody. In addition, method of immunocapture RT-PCR using this IgY was developed for sensitive, efficient, and rapid detection of LMoV. Based on these results, large-scale bulb tests and detection of LMoV in epidemiological studies can be performed routinely using this IgY. This is the first report of production of a polyclonal IgY against a plant virus and its use for diagnosis.