• Parasites, Hosts and Diseases
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• v.56 no.5
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• pp.437-446
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• 2018

To investigate the prevalence of Toxoplasma gondii in pork on the market in Korea, an in-house enzyme-linked immunosorbent assay for tissue fluid (CAU-tf-ELISA) was developed using a soluble extract of T. gondii RH strain tachyzoites. As the standard positive controls, the piglets were experimentally infected with T. gondii: Group A (1,000 cysts-containing bradyzoites), Group B (500 cysts-containing bradyzoites) and Group C ($1.0{\times}10^3$ or $1.0{\times}10^4$ tachyzoites). The CAU-tf-ELISA demonstrated infection intensity-dependent positivity toward tissue fluids with average cut-off value 0.15: 100% for Group A, 93.8% for Group B and 40.6% for Group C. When tissue-specific cut-off values 0.066-0.199 were applied, CAU-tf-ELISA showed 96.7% sensitivity, 100% specificity, 100% positive and 90.0% negative predictive values. When compared with the same tissue fluids, performance of CAU-tf-ELISA was better than that of a commercial ELISA kit. Of the 583 Korea domestic pork samples tested, anti-T. gondii antibodies were detected from 9.1% of whole samples and 37.9% from skirt meat highest among pork parts. In the 386 imported frozen pork samples, 1.8% (skirt meat and shoulder blade) were positive for anti-T. gondii antibodies. In Korea, prevalence of anti-T. gondii antibodies in the pork on retail markets appeared high, suggesting that regulations on pig farming and facilities are necessary to supply safe pork on the tables.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.654-661
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• 2019

The soybean cyst nematode, Heterodera glycines, is a major plant-parasitic nematode that has caused important economic losses to Korea's soybean production. Four species of cyst nematodes, H. schachtii, H. glycines, H. trifolii, and H. sojae, all belong to schachtii group are coexist in field soil in Korea. The rapid identification of the nematode is crucial for preventing crop damage and in decision making for controlling this nematode. This study aimed to develop a species-specific primer set for quantitative PCR (qPCR) assay of H. glycines. The specific primer set (HGF1 and HGR1) for H. glycines was designed based on the cytochrome c oxidase subunit I (COI) sequence of mitochondrial DNA. After optimization, it is possible to identify the H. glycines using a qPCR assay with DNA extracted from a single cyst and single second-stage juvenile (J2). The specificity was confirmed by the absence of SYBR fluorescent signals of three other Heterodera species. A serial dilution of DNA extracted from a single cyst was obtained for the sensitivity test. The result showed that the standard curve of the test had a highly significant linearity between DNA concentration and Ct value (R² = 0.996, slope = -3.49) and that the detection limit concentration of DNA of the primer set was 10 pg of DNA per reaction. Our findings suggested that H. glycines could be distinguished from H. sojae and other Heterodera species when a qPCR assay is used with a specific primer set.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1716-1721
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• 2021

Chikungunya fever is an arboviral disease caused by the Chikungunya virus (CHIKV). The disease has similar clinical manifestations with other acute febrile illnesses which complicates differential diagnosis in low-resource settings. We aimed to develop a rapid test for CHIKV detection based on the nucleic acid lateral flow immunoassay technology. The system consists of a primer set that recognizes the E1 region of the CHIKV genome and test strips in an enclosed cassette which are used to detect amplicons labeled with FITC/biotin. Amplification of the viral genome was done using open-source PCR, a low-cost open-source thermal cycler. Assay performance was evaluated using a panel of RNA isolated from patients' blood with confirmed CHIKV (n = 8) and dengue virus (n = 20) infection. The open-source PCR-NALFIA platform had a limit of detection of 10 RNA copies/ml. The assay had a sensitivity and specificity of 100% (95% CI: 67.56% - 100%) and 100% (95% CI: 83.89% - 100%), respectively, compared to reference standards of any positive virus culture on C6/36 cell lines and/or qRT-PCR. Further evaluation of its performance using a larger sample size may provide important data to extend its usefulness, especially its utilization in the peripheral healthcare facilities with scarce resources and outbreak situations.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.135-142
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• 1990

The quality improvement of antigen (crude saline extract) of Spirometra maptscni 1)lerocercoid (sparganum) was investigated by protein purificatioll. The crude extract was fractionated by gel filtration through Sephacryl S-300 Superfine. Its third fraction was purified by affinity chromatography using a monoclonal antibody as ligand. When observed by SDS-PAGE, the purified protein was composed of 2 bands of 36 kDa and 29 kDa which were found already as the most sensitive components in the crude extract by immunoblots with patients sera. The quality of the purified antigen was evaluated in comparison with the crude extract by ensyme-linked imnunosorbent assay (ELISA) for the specific (IgG) antibody in sera of human sparganosis, other parasitic and neurologic diseases, and normal control. When the purified antigen was used: the sensitivity was not altered but remained high (96.4%) while the specificity was increased from 86.8% to 96.9%.

• Korean Journal of Plant Taxonomy
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• v.43 no.2
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• pp.81-89
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• 2013

In general, studies of aerial parasitic plants known collectively as mistletoe have been carried out to investigate their ecological and agricultural characteristics. However, with the recently increased level of interest in medicinal resources, research on different types of Korean mistletoe has also increased. This study was carried out to review the work on the taxonomy and ecology of Korean mistletoe in preparation for the industrial use of these plants in the future. Mistletoe types are flowering plants belonging to Santalales, which exist in the form of parasites on the branches of trees or shrubs. In Korea, five taxa of four genera in two families of mistletoe exist: Viscum coloratum (Komarov) Nakai f. coloratum, Viscum coloratum (Komarov) Nakai f. rubroaurantiacum (Makino) Kitagawa and Korthalsella japonica (Thunb.) Engl. in Santalaceae, along with Loranthus tanakae Franch. et Sav. and Taxillus yadoriki (Sieb. ex Maxim.) Danser in Loranthaceae. As taxonomic studies of these species remain insufficient and given that the distribution ranges of these species are very wide, further observations pertaining to the morphological variations in each species are necessary. The distribution of mistletoes is known to be determined by the host specificity, the interval between the hosts, the environmental condition, the habits of the host plant, the eating characteristics of mediators in the area, and their habitat selection features.

• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.149-156
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• 1993

Monoclonal antibodies (Mabs) were produced against crude scolex extract of T solium metacestodes, and applied to ELISA-inhibition test for improving the specificity of serodiagnosis of human cysticercosis. Four hybridomas secreting species-specific anti- cysticercal Mabs (Cya-1, Cya-7, Cya-28 and Cya-31) were selected. Each Mab reacted on antigenic components of 25.5 kDa (Cya-1), 28 kDa (rcya-7), 87.5 kDa (Cya-281), and 12.5 kDa (Cya-31). IFA showed that Cya-1 was located at the calcium corpuscles, and Cya-7 at the loose connective tissue of T soLium metacestode scolex. Cya-28 and Cya-31 reacted on the tegument of the scolex. By conventional ELISA, 23 out of 28 (82.1%) cysticercosis patients were found serologically positive, but 1 out of 9 (11.1%) sparganosls cases and 6 out of 31 (19.4%) paragonlmiasis cases showed false positives. By ELISA-Inhibition test using species-specific anti-cysticercal Mab Cya-7, 19 out of 28 (67.9%) cystlcercosis cases were found serologically positive, but there were no false positives In other parasitic infections.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.359-369
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• 2007

Amoebophrya is an obligate endoparasitic eukaryotic dinoflagellate infecting host species and eventually killing them within a short period. Because of its host specificity and significant impacts on population dynamics of host species, it has long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). For several decades, the difficulties of culturing host - parasite systems have been a great obstacle to further research on the biology of Amoebophrya but recent success of several culture systems reactivates this research field. In this study, as a preliminary work for understanding the impacts of Amoebophrya on the population dynamics of host species, semimonthly occurrence of infected host dinoflagellates by Amoebophrya spp. had been observed in Jinhae Bay for two years and with a host - parasite system cultivated, host specificity of Amoebophrya spp. on several dinoflagellates was tested. Amoebophrya spp. were observed in the cellular organelle and cytoplasm of several species including Akashiwo sanguinea, Ceratium fusus, Dinophysis acuminata, Heterocapsa triquetra, Oblea sp., Prorocentrum minimum, P. triestinum, Scrippsiella spinifera, and S. trochoidea. Among them two host - parasite systems for an athecate dinoflagellate, A. sanguinea, and for a thecate dinoflagellate, H. triquetra, had been able to be successfully established as laboratary cultures. Cross-infection tests for 6 species of dinoflagellates in which Amoebophrya was observed or had been reported to exist confirmed high preference for host species of the parasite. Through the continuous research on Amoebophrya occurring in Korean coastal waters, we need to maintain various host - parasite culture systems, which will be very helpful for understanding its ecological role in marine food webs and for applying the species to biologically control harmful algal blooms.