• Journal of fish pathology
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• v.27 no.1
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• pp.1-9
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• 2014

The olive flounder, Paralichthys olivaceus is susceptible to viral hemorrhagic septicaemia virus (VHSV) at $15^{\circ}C$ but no mortality at $20^{\circ}C$ even though the virus can grow well in vitro at $20^{\circ}C$. Thus, we designed an experiment to know immune response of olive flounder against VHSV when the host reared at $15^{\circ}C$ or $20^{\circ}C$. cDNA microarray analysis was performed to compare the gene expression patterns of the kidney cells between the host reared at $15^{\circ}C$ or $20^{\circ}C$. The expression of MHC class I, IL-8, myeloperoxidae and endonuclease G-like having function for the antigen presentation and chemokine-factor were up-regulted both the $15^{\circ}C$ and $20^{\circ}C$ during VHSV infection. MHC class II gene existing on antigen-presenting cells and B cell lymphocytes, immunoglobulin (Ig) genes and phagocytosis related genes were down-regulated at $15^{\circ}C$ but highly expressed at $20^{\circ}C$. It can be thought that innate immune related antigen presentation by MHC class I and phagocytosis reaction against VHSV are efficiently occur both the temperature but macrophage or B cell related antigen presentation via MHC class II fails to induce downstream immune reactions (adaptive immunity) to make antibody, and it can be one of the reason that causes high mortality only at $15^{\circ}C$.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.134-138
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• 1999

This study investigated the relationship between attachment site preference of the skin parasite, Entobdella hippoglossi and mucous cell density, moucus cell size and epidermis thickness on the surface of the Atlantic halibut Hippoglossus hippoglossus. Parasites occupying the ventral surface of their host were significantly longer and wider than those found on the other zones of the fish (P<0.05). The mean size of the mucous cells on the front region was significantly greater than the other regions on the dorsal and ventral surface (P<0.05). The average numbers of mucous cells and the epidermal thickness in the skin of the halibut were shown that the front region had significantly higher numbers of mucous cells and thicker layer than the rear region on the dorsal and ventral surface of the halibut, respectively (P<0.05).

• Genomics & Informatics
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• v.20 no.3
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• pp.33.1-33.17
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• 2022

Nervous necrosis virus (NNV) is a deadly infectious disease that affects several fish species. It has been found that the NNV utilizes grouper heat shock cognate protein 70 (GHSC70) to enter the host cell. Thus, blocking the virus entry by targeting the responsible protein can protect the fishes from disease. The main objective of the study was to evaluate the inhibitory potentiality of 70 compounds of Azadirachta indica (Neem plant) which has been reported to show potential antiviral activity against various pathogens, but activity against the NNV has not yet been reported. The binding affinity of 70 compounds was calculated against the GHSC70 with the docking and molecular dynamics (MD) simulation approaches. Both the docking and MD methods predict 4 (PubChem CID: 14492795, 10134, 5280863, and 11119228) inhibitory compounds that bind strongly with the GHSC70 protein with a binding affinity of -9.7, -9.5, -9.1, and -9.0 kcal/mol, respectively. Also, the ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties of the compounds confirmed the drug-likeness properties. As a result of the investigation, it may be inferred that Neem plant compounds may act as significant inhibitors of viral entry into the host cell. More in-vitro testing is needed to establish their effectiveness.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1992.07a
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• pp.7-19
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• 1992

Fish pathology is one of the main scientific bases upon which this expansion in aquaculture has been dependent and requires a wide knowledge of the environmental constraints, the physiology and characteristics of the various pathogens, the responses of the host and the methods by which they may be controlled. The primary disease and parasite problems in aquaculture animals relate to viral, bacterial, fungal and protozoan epizootics. Parasitic nematodes, trematodes and cestodes are commonly found in aquaculture animals, but seldom are they present in concentrations sufficinet to cause significant problems. When an epizootic does occur and chemical treatment is indicated, the appropriate chemical must be selected and properly applied. We have antibiotics, sulfa, nitrofuran and other chemicals for treatment of fish diseases. Some may be mixed with the fred during formulation, added to the pellets of feed as a surface coating, given in the dorm of an injection or used as a bath. Even though a drug or chemical has been officially approved for use in aquaculture, the substance should never be used unless there is a clear need. Some of the reasions for this view are as follows: (1) the constant use of antibiotics can lead to the development of resistant strains of bacteria, (2) biofilter efficiency may be impaired or destroyed by chemicals added to closed recirculating water systems, and (3) the injudicious use of chemicals can have a damaging effect on the environment as well as on human.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.4
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• pp.307-313
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• 2010

Stanniocalcin 1 (STC1) is a glycoprotein hormone that is important in the maintenance of calcium and phosphate homeostasis in both fish and mammals. STC1 and its paralog STC2 are expressed in multiple tissues in fishes, although the physiological roles of piscine STCs are still unclear compared with those of mammals. In this study, we cloned olive flounder STC1 (ofSTC1) and ofSTC2 cDNAs into pET28a vector and used E. coli Rosetta (DE3) as the host strain for protein expression. Expression experiments were carried out using isopropyl-$\beta$-D-thiogalactoside (IPTG) and nickel affinity chromatography. We could identify the recombinant proteins as single 29.5 kDa (ofSTC1) and 33.2 kDa (ofSTC2) bands in the insoluble fraction on sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE). These results indicate that ofSTC1 and ofSTC2 were expressed as insoluble proteins in E. coli. Furthermore, the injection of ofSTC1 protein into juvenile tilapia resulted in a decrease of the serum calcium level. These results suggest that the purified fish STC1 and STC2 proteins may be used to elucidate the physiological role of STCs in fishes.

• Parasites, Hosts and Diseases
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• v.54 no.4
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• pp.537-541
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• 2016

Stellantchasmus falcatus (Digenea: Heterophyidae) is first reported from Cambodia through recovery of the metacercariae from mullet fish and adult flukes from an experimentally infected hamster. We purchased 7 mullets, Chelon macrolepis, in a local market of Phnom Penh, Cambodia, and each of them was examined by the artificial digestion method on May 2010. The metacercariae of S. falcatus were detected in all mullets (100%) examined, and their average density was 177 per fish. They were elliptical, $220{\times}168{\mu}m$ in average size. They were orally infected to an hamster to obtain adult flukes. Adults recovered at day 10 post infection were observed with a light microscope and a scanning electron microscope (SEM). They were small, $450{\times}237{\mu}m$ in average size, had a small oral sucker ($41{\times}50{\mu}m$), subglobular pharynx ($29{\times}21{\mu}m$), slender esophagus ($57{\mu}m$), long and thick-walled expulsor ($119{\times}32{\mu}m$), spherical ovary ($58{\times}69{\mu}m$), and 2 ovoid testes (right: $117{\times}74{\mu}m$; left: $114{\times}63{\mu}m$). Eggs were small, yellow, and $23{\times}12{\mu}m$ in average size. In SEM observations, tegumental spines were densely distributed on the whole tegument, and single small type I sensory papillae were distributed around the lip of oral sucker. The small ventral sucker was dextrally located and had 8 type I sensory papillae on the left margin. It has been first confirmed in the present study that the mullet, C. macrolepis, is playing the role of a second intermediate host of S. falcatus in Cambodia.

• Journal of fish pathology
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• v.11 no.2
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• pp.137-141
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• 1998

Temperate phages were effectively induced from presumptive lysogenized cells of 96 strains out of 111 strains of L. garvieae No. 44 strains (phage type B) as the host cell. Similar cultures in distilled water-based TSB did not induce lytic infection in these cells. These temperate phages were also effectively induced by ultraviolet irradiation. All phages isolated were lytic only to L. garvieae No. 44 strain and the lytic nature was different from those of PLgY, PLgW, and PLgS. The virions appeared extracellularly after 1h of induction culture and increased in number until reaching the maximum of $10^6$ PFU/ml after 12h. This phage production was lower than that ($10^{10}$ PFU/ml) of the virulent phage.

• Journal of fish pathology
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• v.18 no.3
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• pp.197-204
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• 2005

This study was performed to understand morphological features and classification of different species of cercaria parasitized in Batillaia cummingi, a marine gastropod. Samples were collected from April 2004 to February 2005 in the mud flat of Naecho-do, which is located in the estuary of the Geum river of the Yellow Sea. The mud flat temperature of the study area ranged from 6$^{\circ}C$ to 27$^{\circ}C$ all around the year. Two species of cercaria, Pygidiopsis summus and Cercaria pseudogranifera, were detected through the gonad examination of the gastropod. The minimum and maximum infection rates of Pygidiopsis summus were 0.67% in October and 20.67% in August, respectively. However, P. summus was not detected in December. The infection rate of Cercaria pseudogranifera showed from 9.3% in June to 66.0% in December. These data indicate that Batillaia cummingi should be added as the intermediate host of these parasites.

• Journal of fish pathology
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• v.22 no.3
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• pp.239-251
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• 2009

The effects of microbiological properties and pathogenicity of Photobacterium damselae subsp. damselae were investigated under different culture conditions, temperature, pH, NaCl and iron concentration on culture media. Favorable conditions for bacterial growth were between 15-30${^{\circ}C}$, pH 5-9, 0-4% NaCl concentration and iron contents of over 10 mM, whereas the bacterial growth was inhibited under iron chelator existence. When P. damselae was cultured in iron-limited tryptic soy broth, total protein concentration of extracellular products, cytotoxic ability of ECPs on cell line, bacterial viability in flounder serum, phospholipase and siderophore activities of ECPs were significantly increased. On the other hand, the activities of P. damselae cultured under iron-added conditions were decreased. In this study, the iron-limited conditions were similar to the host in which iron concentration is low. During infection caused by P. damselae, the conditions could be related to the pathogenesis of the pathogen.

• Journal of fish pathology
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• v.23 no.3
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• pp.313-322
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• 2010

Edible tunicate Halocynthia roretzi, one of the most commercially important aquatic organisms in Korea, has been killed by tunic softness syndrome since last decade. The intracellular protistan parasite observed by the transmission electron microscope in hemocytes of the tunicate was considered to be the causative agent of the mass mortality. The goal of the present work is to examine the characteristic features of the parasite by identifying the 18S rDNA sequences of the parasite. The experiments conducted include amplification of presumptive 18S rDNA from diseased tunicate tissues with UNonMet-PCR and sequencing the product. A preliminary phylogenetic analysis was performed on the presumptive parasite rDNA. A digoxigenin labeled DNA probe was designed on the basis of the sequences of rDNA. Dig-ISH assay was conducted to diagnose the protistan parasite. A PCR using UNonMet-PCR primer generated 595 bp SSU rDNA fragment. Subsequently, PCRs with primer pair expended this sequence to 1542 bp. This is the first partial sequences of SSU rDNA gene to be published on the protistan parasite that has presumed causing the mass mortality of tunicate. Since the Dig-ISH technique demonstrated the presence of infection in hemocytes on the all host tissues, the fragment was confirmed to be the intracellular protistan parasite SSU rDNA. A phylogenetic analysis suggested that the protistan parasite may be a unique eukaryote that is closely related to Apicomplexa.