• Journal of Life Science
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• v.26 no.6
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• pp.737-748
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• 2016

By this time, insect antimicrobial peptides (AMPs) have been characterized more than 150 peptides since purification of cecropin in the hemolymph of pupae from Hyalophora cecropia in 1980. Therefore, it is considered that insects are good sources of AMP selection. Insect AMPs are small (low molecular weight) and cationic, and amphipathic with variable length, sequence, and structure. They perform a pivotal role on humoral immunity in the insect innate immune system against invading pathogens such as bacteria, fungi, parasites, and viruses. Most of the insect AMPs are induced rapidly in the fat bodies and other specific tissues of insects after septic injury or immune challenge. Then the AMPs subsequently released into the hemolymph to act against microorganisms. These peptides have a broad antimicrobial spectrum against various microbes including anticancer activities. Insect AMPs could be divided into four families based on their structures and sequences. That is the α-helical peptides, cysteine-rich peptides, proline-rich peptides, and glycine-rich peptides/proteins. For instance, cecropins, insect defensins, proline-rich peptides, and attacins are common insect AMPs, but gloverins and moricins have been identified only in lepidopteran species. This review focuses on AMPs from insects and discusses current knowledge and recent progress with potential applications of insect AMPs.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.237-243
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• 2018

The pathogenic free-living amoebas (FLAs), Acanthamoeba spp. and Naegleria fowleri, can cause fatal infections, including amoebic encephalitis. They are ubiquitously distributed in nature, including in diverse bodies of water. In order to survey Acanthamoeba spp. and N. fowleri in source water in Korea, we used culture-based real-time PCR to detect viable FLAs in 52 source water samples collected between July 2017 and December 2017. Acanthamoeba spp. and N. fowleri were detected in 42 samples (80.8%) and 6 samples (11.5%), respectively. Acanthamoeba spp. were detected at approximately the same frequency in all seasons, but N. fowleri was mainly detected in summer and autumn, with no N. fowleri detected in winter. These results demonstrate that these pathogenic FLAs, especially N. fowleri, which has caused deaths in the United States and China, are widely distributed in the Korean aquatic environment.

• Parasites, Hosts and Diseases
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• v.32 no.3
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• pp.195-200
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• 1994

Malaria is estimated to have a worldwide incidence of more than 100 million clinical cases and approximately 1 miuion deaths per year. Korea, although previously tnlown as an endemic area of tertian malaria (Pzosmonin vivax), has been considered free from malaria as there had been no report on indigenous cases since 1984. Recently, however, we experienced an indigenous case of P. viuax infection in a young man who had never been abroad. The patient was a 23-year-old Korean soldier with 18-day history of recurrent fever and chill lasting 4 to 8 hours on alternative days since mid-July 1993. He had lived in Changwon, Hyongsangnam-do, before entering barracks located in Paiu-gun, Kyonggj-do on Jne 1992, and had never been out of Korea. He had no history of blood transfusion nor parenteral use of drugs. The peripheral blood smears showed typical ring forms, trophozoites, and gametocytes of p. uiuox, in addition to mild anemia and thrombocytopenia. After confirmation of the diagnosis, he was treated with hydroxychloroquine and primaquine. Follow-up blood smears no more revealed malaria parasites. It is not certain whether the present case is due to a resurgence of indigenous malaria or a secondary infection from introduced mnuia. Whichever the source of infection the domestic occurrence of mnuia cycle in Korea should be a warning sign in public health point of view.

• Parasites, Hosts and Diseases
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• v.57 no.6
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• pp.671-680
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• 2019

Cathepsin D (CatD, EC 3.4.23.5) is a member belonging to the subfamily of aspartic endopeptidases, which are classified into the MEROPS clan AA, family A1. Helminth parasites express a large set of different peptidases that play pivotal roles in parasite biology and pathophysiology. However, CatD is less well known than the other classes of peptidases in terms of biochemical properties and biological functions. In this study, we identified 2 novel CatDs (CsCatD1 and CsCatD2) of Clonorchis sinensis and partially characterized their properties. Both CsCatDs represent typical enzymes sharing amino acid residues and motifs that are tightly conserved in the CatD superfamily of proteins. Both CsCatDs showed similar patterns of expression in different developmental stages of C. sinensis, but CsCatD2 was also expressed in metacercariae. CsCatD2 was mainly expressed in the intestines and eggs of C. sinensis. Sera obtained from rats experimentally infected with C. sinensis reacted with recombinant CsCatD2 beginning 2 weeks after infection and the antibody titers were gradually increased by maturation of the parasite. Structural analysis of CsCatD2 revealed a bilobed enzyme structure consisting of 2 antiparallel β-sheet domains packed against each other forming a homodimeric structure. These results suggested a plausible biological role of CsCatD2 in the nutrition and reproduction of parasite and its potential utility as a serodiagnostic antigen in clonorchiasis.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.195-200
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• 2020

Soil-transmitted helminths, including Ascaris lumbricoides and Trichuris trichiura, are important intestinal parasites mostly affecting younger people in developing countries. In 2014-2015, we performed mass fecal examinations targeting a total of 2,227 schoolchildren in 3 districts (South Dagon, North Dagon, and Hlaing-thar-yar) of Yangon Region, Myanmar, using the Kato-Katz thick smear technique. The egg positive children were subjected to a mass drug administration (MDA) using a single oral dose of 400 mg albendazole. The pre-treatment egg positive rate (EPG/person) of A. lumbricoides averaged 17.2% (15,532); it was 25.2% (21,796), 14.2% (11,816), and 12.8% (12,983) in 3 districts, respectively, and that of T. trichiura averaged 19.4% (1,074), and was 24.1% (1,040), 12.3% (852), and 21.2% (1,330) in 3 districts, respectively. Follow-up fecal examinations performed 4 months post-MDA revealed considerable decreases of A. lumbricoides prevalence (EPG/person) to av. 8.3% (12,429), and 13.7% (17,640), 8.0% (7,797), and 4.5% (11,849) in 3 districts, respectively. However, T. trichiura did not show any recognizable decrease in the prevalence (EPG/person) remaining at av. 18.2% (862), and 18.5% (888), 11.5% (812), and 23.3% (887) in 3 districts, respectively. The results demonstrated difficulty in short-term control of T. trichiura by MDA using albendazole and suggested necessity of either a long-term MDA (>10 years) or changing the albendazole regimen into 2~3-day course (total 800 or 1,200 mg), or using an alternative drug/drug combination.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.147-152
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• 2020

Malaria is a potent burden on public healthcare worldwide due to requiring rapid diagnosis and treatment. Nowadays, prompt diagnosis with rapid diagnostic tests (RDTs) has been widely accepted as an effective diagnostic technique in malaria-endemic countries, primarily due to their easy operation, fast output, and straightforward interpretation. The global availability and use of RDTs have gradually grown over recent decades as field-applicable diagnostic tests for the reliable confirmation of malaria infection and proper case management. This study was conducted to evaluate diagnostic performance of 3 commercially available malaria RDT kits : BIOCREDIT^TM Malaria Ag Pf(pLDH), Malaria Ag Pf(pLDH/pHRPII), and Malaria Ag Pf/Pv(pLDH/pLDH) (where pLDH and pHRPII stand for plasmodium lactate dehydrogenase and histidine-rich protein 2, respectively) for the specific detection of Plasmodium falciparum. A total of 1,129 blood samples including 95 blood samples, confirmed as vivax malaria infection by microscopic examinations and a nested-PCR method, were tested for falciparum malaria infection. The overall sensitivity and specificity of Malaria Ag Pf(pLDH/pHRPII), Malaria Ag Pf/Pv(pLDH/pLDH), and Pf(pLDH) for P. falciparum were 99.0% and 100%, 95.8% and 100%, and 100% and 100%, respectively. It is proposed that the 3 RDT kits perform reliable level of diagnostic accuracy of detection for P. falciparum parasites.

• Journal of fish pathology
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• v.25 no.3
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• pp.231-241
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• 2012

Diagnostic monitoring in fish farms with land-based tanks and netpen cases were conducted in eastern, western, southern and Jeju island of Korea during summer of 2007~2011. In total, 2413-fish samples of 4 marine fish species were tested for the detection of bacteria and parasite. Fish species tested were olive flounder (Paralichthys olivaceus), black rockfish (Sebastes schlegeli), red sea bream (Pagrus major), pacific white shrimp (Litopenaeus vannamei). During the diagnostic monitoring from 2007 to 2011, the infection rates by single infection of bacterial or parasitic pathogens were relatively higher than the mixed infections. The main bacterial pathogens in olive flounder, black rockfish and pacific white shrimp were Vibrio spp. (V. harveyi, V. ichthyoenteri, Vibrio sp.). The main bacterial pathogens in red sea bream were also Vibrio sp. and Photobacterium damselae subsp. damselae. The main parasitic pathogens were both Miamiensis avidus and Trichodina sp. in olive flounder, Microcotyle sebastes in black rockfish, Microcotyle tai in red sea bream and Zoothamnium sp. in pacific white shrimp.

• Journal of fish pathology
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• v.25 no.3
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• pp.151-158
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• 2012

Diseased eel (Anguilla bicolor) displayed severe hemorrhages in the gills, and congestion and swelling in the liver. During the epizootic, the water temperature was $28^{\circ}C$ and the morality rates were about 5%. No parasites were found on the gills and skin. Bacteria were not cultured from any internal organs using TSA or SS agar at $28^{\circ}C$ for 48 hrs. Histopathologically, the gills showed epithelial hyperplasia in the base of secondary gill lamellae and hemorrhages in the capillaries. Some cells in the proliferated interlamellar epithelia exhibited marginal hyperchromatosis. And severe vacuolated changes in the parenchymal cells and congestion in the central veins were observed in the liver. The specific amplicon (396 bp) was detected from gills and opercula of affected eel PCR using Anguillid herpesvirus-1 (AngHV-1) -specific primer sets HVAPOLVPSD (5-'GTG TCG GGC TTT GTG GTG C-3') and HVAPOLOOSN (5'-CAT GCC GGG AGT CTT TTT GAT-3'). Sequencing analysis of the amplicon demonstrated that this gene was 99% homologous to the AngHV-1 sequence deposited in GenBank. This is the first report of AngHV-1 outbreak in the farmed shortfin eels (A. bicolor) in Korea. When diseased fish were maintained for 10 days at water temperatures of $32^{\circ}C$ and $35^{\circ}C$, the cumulative mortalities were 100% and 10%, respectively. Even though the AngHV-1 genome in the gills from the eel kept at $35^{\circ}C$ was detected using PCR, the structure of gill filaments was similar with that of normal fish. Increasing the water temperature to $35^{\circ}C$ was an effective way to diminish the mortality of AngHV-1 affected eel.

• Journal of fish pathology
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• v.23 no.3
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• pp.369-377
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• 2010

The epidemiological study was performed to survey the prevalence of fish pathogens of cultured olive flounder, Paralichthys olivaceus collected in Pohang, Ulsan.Gijang, Keoje and Wando area of Korea from 2005 to 2007. In this study, the fish pathogens were detected from 1,528 among 2,238 fish samples and annual incidences were 60.6% in 2005, 66.7% in 2006 and 72.3% in 2007, respectively. Seasonal prevalence was 63.5% in February, 67.3% in May, 75.1% in August and 64.2% in November for three years. The detection rates of parasites, bacteria or viruses were 36.7%, 32.8% and 31.4%, respectively. 775 cases (34.6%) among 2,238 fish samples showed mixed infection with a different pathogens. The distribution of specific diseases showed that detection rates of diseases occurring the most frequently during the study period were Trichodina spp., (28.2%), viral nervous necrosis virus (24.3%), Vibrio (11.6%), viral hemorrhagic septicaemia virus (10.5%).

• Journal of Korean Society of Forest Science
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• v.76 no.4
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• pp.376-389
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• 1987

Higher fungi (Basidiomycetes) were collected from forest stands of Kwangnung Experimental Forest, Kwangnung, Kyonggido, during the summer and fall seasons of 1976, 1984, 1985 and 1986. A total of 257 species and varieties in 104 genera were identified. Saprophytic fungi accounted for 135 species in 75 genera while mycorrhizal fungi accounted for 120 species in 28 genera. Two parasitic species were collected and they were root parasites. Among the mycorrhizal species Amanita, Russula, Lactarius, and species in the Boletaceae were the dominant taxa. The mycorrhizal fungi appear to be an important component in the essential elements needed for forest management in Korea. A reevaluation of the higher fungi previously described in Korea was made and we report 77 higher fungi previously undescribed from Korea. This is from a single experimental forest and suggests that there are many unreported higher fungi which play an important role in Korean forests.