• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.109-109
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• 2002

Detection of protozoan parasites Perkinsus sp. and P. atlanticus was developed in this study using a specific polymerase chain reaction (PCR) to diagnose the presence of those organisms that causes extensive mortalities of marine shellfishes. The PCR was conducted together with fluid thioglycollate medium (FTM) method and 2 M NaOH lysis method. For the test, Manila clams, Ruditapes philippinarum, were collected from four coastal locations in Korea including Wando Island, Gimnyeong, Sungsan and Sogwipo in Jeju. In addition, trophozites of Perkinsus sp. cultivated in vitro and the granular ark clam, Tegillarca granosa, taken from Gangjin on the south coast of Korea, were used as positive and negative controls, respectively. Expected DNA bands were detected in the samples from Wando Island, Sungsan and the in vitro cultured Perkinsus sp. when the probes specific for the genus Perkinsus and P. atlanticus were used. The samples were also positively diagnosed by the FTM and 2 M NaOH methods. In contrast, the Manila clams from Gimnyeong and Sogwipo, and the granular arks clams from Gangjin showed no detectable signs of infection with the PCR, the FTM method and the 2 M NaOH lysis method. On the other hand, being amplified by p. atlanticus specific primer, it is suggested that the protozoan parasite Perkinsus sp. found in the Korean Manila clam is P. atlanticus. Finally the PCR- based assay developed in the present study can be used in detection of Perkinsus infection and discrimination of Peykinsus species in quarantine stations or laboratories due to the high sensitivity and specificity as well as its rapid detection.

• Journal of fish pathology
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• v.9 no.2
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• pp.119-126
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• 1996

We report on the variation of infection and histopathological change of Microcotyle sebastisci parasitic on cultured rockfish, Sebastes schlegeli, in Namhae Islands and Kamak Bay from April to October in 1995. Microcotylosis due to Microcotyle sebastisci occurred among cultured rockfish, Sebastes schlegeli. This parasite was not found on the host fish from June to July. Parasite sites were mainly consist of 2nd and 3rd gill arch`s filaments of rockfish. Also, the sites were secreted in large quantity of mucus with a very small bleeding. In Namhae Islands, maximum values of prevalence, relative density and mean intensity were found on September 1995, as 40.0%, 30.7 and 76.8, respectively. In Kamak Bay, maximum values of prevalence, relative density and mean intensity were obtained on October 1995, as 46.0%, 40.5 and 88.0, respectively. Histopathological changes of the heavily infested gills were showed necrosis, epithelium of the gill filaments underwent hyperplasia with fusion of the lamella and filamental clubbing. And a bacterial colony is invaded on the surface of lamella epithelium.

• Journal of fish pathology
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• v.22 no.1
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• pp.9-14
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• 2009

Fifteen diseased rockfish (Sebastes schlegeli) were collected from 4 net-cage farms in Huksan island. Some round transparent nodules were observed on gill filaments in fish. Bacteriological and histopathological examinations on the diseased fish were performed. Any pathogenic bacteria could not be isolated from the internal tissues and histopathological alterations were not found in any of the tissues except the gills. Rock fish were infected with epitheliocystis, Microcotyle sebastes and unknown aetiology on the gills. Cysts of epitheliocystis measuring 44.1-68.9 $\mu{m}$ in diameter were mainly found in the distal portion of the gill filaments and sometimes in the middle portion. But host responses were moderate in spite of formation of the epithelial cysts. Some Microcotyle sebastes captured the secondary filaments with clamps on the opisthohaptor. Attachment of the parasites provoked epithelial proliferation and resulted in gill lamellar fusion.Cysts of unknown origins measuring 26-425 $\mu{m}$ in diameter were found in the cartilage of gill filaments. These cysts contained eosinophilic materials and proliferation of cartilage cells was confirmed around the cysts. But there was no significant pathological changes associated with the presence of the cysts except enlargement of the gill filament with the cysts.

• Parasites, Hosts and Diseases
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• v.58 no.1
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• pp.67-72
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• 2020

Human infection with Echinostoma aegyptica Khalil and Abaza, 1924 (Trematoda: Echinostomatidae) is extremely rare. In this study, we confirmed E. aegyptica infection in 5 riparian residents living along the Mekong River in Savannakhet Province, Lao PDR. The patients revealed eggs of Opisthorchis viverrini/minute intestinal flukes, echinostomes, and other parasites in fecal examinations using the Kato-Katz technique. Following treatment with praziquantel 30-40 mg/kg and pyrantel pamoate 10-15 mg/kg in a single dose and purging with magnesium salts, adult specimens of various helminth species were collected. Among the trematodes, echinostome flukes of 4.5-7.6 mm in length (n = 134; av. 22.3 specimens per case) were of taxonomic interest and subjected in this study. The flukes were morphologically characterized by having total 43-45 collar spines arranged in 2 alternating rows (corner spines usually 5 on each side) and compatible with previous descriptions of E. aegyptica. The patients were mixed-infected with other helminths, so specific clinical manifestations due to this echinostome fluke were difficult to determine. The present paper describes for the first time human E. aegyptica infections in Lao PDR. This is the second report of human infection (2nd-6th cases) with E. aegyptica in the world following the first one from China.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.586-590
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• 2009

Horsehair worms (Chordodes koreensis) develop as parasites in the bodies of grasshoppers, crickets, cockroaches, and some beetles. Chordodes koreensis is an accidental parasite of humans, livestock, or pets and poses no public health threat. The male of Chordodes koreensis in the later larval stage from canine vomitus was investigated by the scanning and transmission electron microscopy. In cross sections, the body wall is composed of four components namely epicuticle, cuticle, epidermis, and muscle layers. The parenchymal tissue fills the rest of the body and surrounds the visceral organs such as intestine, and ventral nerve cord but testes were not found. The epicuticle is a thin superficial layer whose surface shows rows of polygonal elevations called areoles. The cuticle has 17 layers of collagenous fibers spirally wound about the long axis of the worm. The section through the cuticle reveals the layers of large fibers cut obliquely lengthwise, alternating with layers of fibers sectioned obliquely crosswise. The layers of large fiber formed a double helix about longitudinal axis of the worm. The epidermis is a single layer. The muscles were interrupted by the nervous lamella in the only midventral portion. The medulla of muscle plate is composed of lightly stained cytoplasm, mitochondria, weakly developed endoplasmic reticulum, and glycogen granules. Between the medulla of a cell and the plasmalemma lies a broad cortical zone of myofilaments. The circular muscles are absent. The characteristic feature of the cytoplasm is that there was no content in peripheral mesenchyme, but was an abundance of large clear vacuoles which give the cytosome a foamy appearance. The nucleus of mesenchyme is not easily identified in our specimens.

• Journal of Veterinary Clinics
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• v.17 no.2
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• pp.443-449
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• 2000

A three-year-old male jindo with generalized skin lesions (including seborrhea, hyperk- eratosis, alopecia, papules, and ecchymoses), pruritus lymph node enlargement, and fever was brought to Veterinary Teaching Hospital, College of Veterinary Medicine, Chungbuk National Uni- versity. There were no laboratory findings for parasites and fungi in the hair and skin But, the com- plete blood counts (CBC) showed leukocytosis and severe cosinophilia, It was suspected to be an inflammatory and allergic dermatitis. Thus, prednisoIone (0.5 mg/kg PO, BID for 1 week) and ampi- cillin (10 mg/kg PO, BID for 1 week given. One week later, pruritus and ecchymoses were reduced. These treatments were repeated for 7 day again. Three months later, the dog was presented again due to the relapse and exacerbation of the clinical signs. The signs were as follows; severe pru- ritus, vesicobullous skin lesions, anorexia, emaciation, lameness, and welling of carpal joints that showed inflammatory skin lesion and draining of synovia-like fluid. The values of WBC counts were returned to normal ranges. In contrast, eosinophilia was still observed. Coombs test for patient RBC and serum were negative. Hypoalbuminemia (2.5g/dl) was shown by serum chemistry. The uri- nalysis revealed and presence of leukocytes. Luxation finding of right radial carpal joint by polyarthritis was shown in radiography of affected joints.Lupus eryhematosus(LE) cells also appeared in peripheral blood and synovial fluid of affected joints. Definitely, antinuclear antibody (ANA) of patient serum using feline peripheral blood mononuclear cells was detected by all immu- nofluorescence. Based on these findings such as sedum ANA-Positive. major signs (skin disease, non- erosive polyarthritis with soft tissue swelling. and proteinuria), minor signs (fever), and LE cell-pos- itive, a diagnosis of systemic lupus crythematosus (SLE) was mad\ulcorner in this dog. The dog with SLE was administered with Pre(2.0 mg/kg PO, BID for first 4 week and then QOD) to inhibit the production of autoantibodies and with ampicillin (10 mg/kg PO, BID for first 4 weeks and then QOD) to prevent the secondary infection. The condition of this dog was monitored every 2 weeks by physical examinations, radiography, CBC, serum chemistry and urinalyais. At 8th week of treat- ment, the state of SLE evaluated by physical examinations and laboratory findings was markedly improved except for proteinura.

• Korean journal of applied entomology
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• v.21 no.2 s.51
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• pp.87-94
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• 1982

The mymarids egg parasite of rice planthopper, Anagrus nr. flaveolus, were investigated to know their parasitic activities after overwitering in the paddy banks and barley fields, their host preferences and seasonal variations in the pesticide sprayed and unsprayed paddy fields of Gyeongnam province O.R.D. at Jinju from 1977 to 1979. The parasitic activities of Anagrus nr. flaveolus after overwintering in the paddy banks were high early in April and tended to decrease remarkably since mid-April by moving to the barley fields. The parasitic rate of Anagrus nr. flavelous was $47.2\~88\%$ between middle and late in April, the peak of egg deposition period. Anagrus nr. flaveolus parasitized Laodelphax striatellus, Nilaparvata lugens, and Sogatella furcifera, but didn't attack the eggs of Nephotettix cincticeps in the paddy fields. High preference was observed with Laodelphax steriatellus. The parasitic activities of Anagrus nr. flaveolus in the pesticide sprayed paddy fields were high in early July and from late August to early September. The parasitic rate in the pesticide unsprayed fields were higher than those of sprayed fields during the pesticide spraying period, from July to August and parasitic activities were active from October to before coming winter.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.30-41
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• 2017

Mammals in Korea have been studied in various fields such as animal science, veterinary medicine, laboratory animal science, ecology, and genetics. As the importance of biodiversity has been emphasized recently, conservation and management of mammals have attracted much public attention. However, in spite of such an increase in scientific research and public interest, it is still difficult to find a report or summary to grasp the trend of mammalian research in Korea. The purpose of this study is to provide the basic data for future plans of the detailed research area and the related policies by grasping the research trends of mammals in Korea. Using text-ming and co-word analysis, we analyzed 392 mammalian research papers published in Korean national journals as of 2015. Our results showed that the number of mammalian research papers published in Korea has gradually increased and that the research target species have also become increasingly diverse. The major research areas identified through text-mining and co-word analysis are (1) evolution/phylogenetics/genetics, (2) environmental science/ecology, (3) embryology/reproductive biology/cell biology, (4) veterinary medicine related to parasites, (5) parasitology related to rodents, (6) bacteriology/virology, (7) anatomy/cell biology/laboratory animal science, (8) veterinary science related to morphology and anatomy, (9) animal science, (10) marine mammalogy, and (11) Chiroptera (bat) research. Environmental science/ecology has been the most active field among the 11 research areas in recent times, and the proportion of research has increased sharply compared to the past. Environmental science/ecology is the core of biodiversity conservation, and as the importance of biodiversity has been emphasized in recent years, researchers' interest in mammal ecology appears to have increased. We expect that the results of this study will be useful for future research plan and related policies on mammals in Korea.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.65-71
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• 2012

Protozoan parasites belonging to the genus Perkinsus elicit severe inflammatory responses and are associated with mass mortality of commercially important marine shellfish worldwide. In the present study, we examined the external features of P. olseni zoospores in detail using light and scanning electron microscopy. Our study showed that the zoospores have an oval body with a long anterior flagellum and a short posterior flagellum. The anterior flagellum has a unilateral array of mastigonemes. Mean body dimensions were $3.37{\pm}0.33{\mu}m{\times}1.72{\pm}0.22{\mu}m$. The average length of the anterior and posterior flagella was $16.34{\pm}1.52{\mu}m$ and $8.25{\pm}1.39{\mu}m$, respectively. Zoospores of P. olseni found in Korean waters have shorter and narrower bodies, longer anterior flagella, and shorter posterior flagella than zoospores of Perkinsus spp. found in the mollusks of North America and Europe.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.