• Fisheries and Aquatic Sciences
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• 제3권2호
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• pp.111-117
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• 2000

To clarify the ichthyotoxic mechanisms of a harmful dinoflagellate Cochlodinium polykrikoides, hematological responses of the flounder Paralichthys olivaceus and red sea bream Pagrus major exposed to this algal bloom were investigated. The mortality of red sea bream was considerably larger than that of flounder, and the threshold lethal density of C. polykrikoides to the test fish was approximately 3,000 cells/ml. Blood $PO_2$declined in proportion to the increasing density of algal cells. The blood $PO_2$ of moribund fish was about $40-60\% of control test fish. Particularly, the fishes began to be killed when the blood $PO_2$ fell below 30-40 mmHg. However, the blood pH dropped almost 1.0 unit just before fish kill. Hemoglobin and hematocrit levels of fish exposed to C. polykrikoides of 5,000 cells/ml for 24 h and of moribund fish did not show great difference. The concentrations of plasma $Na^+$, $K^+$ and $Cl^-$ were slightly elevated to different magnitudes except $Ca^{2+}$ and plasma osmolality was also increased in Cochlodinium-exposed fish. In the plasma cortisol level, these values of moribund flounder and red sea bream were 4- 5 times higher than those of control fish. These results suggest that the drop of blood $PO_2$ was may be one of the principal causes of fish kill by C. polykrikoides, and the changes of other hematological parameters were secondary responses elicited by the decrease in blood $PO_2$.

• 한국임상수의학회지
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• 제26권2호
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• pp.150-154
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• 2009

최근 doctor fish(Gara rufa obtusa)를 이용한 Ichthyotherapy는 인간 피부질환의 대체 치료법으로 각광받고 있으며, 근래 doctor fish의 국내 증식 성공으로 인하여 이러한 추세는 증가되고 있다. 그러나 doctor fish의 질병과 생태에 대해서는 아직 연구가 미미한 실정이다. 본 보고는 국내에서 증식되던 doctor fish가 Citrobacter freundii에 감염되어 집단 폐사한 예로서, 병어에 대한 외부 및 내부 진단, 분리된 세균의 형태학적, 생화학적 동정을 통하여 C. freundii를 확정하였으며, 분리된 C. freundii에 대한 항생제 감수성 검사를 수행하였다. 또한 살아남은 병어에 대한 집단 치료를 시도하여 성공적인 치료 효과를 얻을 수 있었다.

• 한국어병학회지
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• 제17권3호
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• pp.213-216
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• 2004

To confirm the possibility of a wild marine crab, Gaetice depressus, as a carrier for white spot syndrome virus (WSSV) and to develop an alternative experimental model for WSSV in winter season, the susceptibility of the crab to WSSV was assessed by artificial challenge and subsequently tested for infection by PCR assay. The results revealed that the crabs were as highly susceptible as penaeid shrimps. WSSV caused 100% mortality in G. depressus within 16 days after intramuscular injection. The presence of WSSV in the moribund crabs was confirmed by PCR and was found in gills and muscle tissue. These results suggest that G. depressus can be naturally infected by WSSV via moribund shrimps, and can act as a potential carrier of WSSV. In addition, G. depressus can be used as an alternative experimental animal for WSSV.

• 한국식품위생안전성학회지
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• 제17권4호
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• pp.193-200
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• 2002

Cochlodinium polykrikoides 적조로 폐사한 어류를 식품원료나 사료로 이용하기 위한 기초연구의 일환으로 방어(Seriola quinqueradiata), 넙치(Paralichthys olivaceus) 및 조피볼락(Sebastes schlegeli) 등 양식어류 3종을 이 적조에 노출하여 치사시켰다. 이 치사어류를 동 적조수에 저장하면서 저장시간에 따른 생균수, 휘발성염기질소 및 관능적 변화 등을 공기 중에서 질식시킨 후 신선한 해수에 저장한 어류와 비교하였다. 시험어 근육중 생균수는 저장 6시간 이후부터 증가하는 경향을 보였고, 휘발성염기질소는 지속적으로 증가하는 경향이었다. 치사 후 해수에 저장된 각 시험어 근육중 휘발성염기질소 및 생균수 함량의 변화는 적조해수에서 치사.저장한 시험구가 공기 중에서 질식시킨 대조구보다 약간 빠른 증가 경향을 보였으나, 시험구와 대조구간의 관능적 변화의 차이는 뚜렷하지 않았다. 적조로 폐사한 어류 3종을 해수에 저장하였을 때 12시간이 경과하여도 근육에서 초기 부패단계의 기준인 VBN 30 mg/100g 및 생균수 $10^{5}$ CFU/g을 초과하지는 않았으나 관능적 변화는 6시간 이후에는 변화가 나타나 적조 폐사어는 6시간 이내에 처리하여야 할 것으로 판단되었다.

• 한국어병학회지
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• 제32권2호
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• pp.81-89
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• 2019

As an epidemiological survey, mortality of marbled rockfish, Sebastiscus tertius observed from a fish farm in Gyeongnam province of South Korea. The major macroscopic sign of the diseased fish was severe multifocal dermal ulceration. Histological observation revealed inflammation, necrosis and colonization of bacteria in various tissues (gill, liver, spleen and kidney). Bacteria was isolated from spleen and kidney in moribund and mortality fish. Seven bacterial isolates from the diseased fish were identified as Aeromonas salmonicida subsp. salmonicida using API 20E and 20NE, API 50CH API ZYM system. Under light microscopy, infected marbled rockfish showed the lifting of the lamella epidermal layer, edematous changes and hypertrophy of epithelial cell in the gill filament. The atrophy of the mucosal fold, erythema in the intestine, and the necrosis of hematopoietic tissue and renal tubule cells with karyolysis were observed in the kidney. In this study was demonstrated the histological reaction of red marbled rockfish infected by Aeromonas salmonicida. Furthermore, this is the first account of extensive dermatitis in Sebastiscus tertius due to atypical A. salmonicida infection, which has high potential in aquaculture among native fish species.

• 한국어병학회지
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• 제21권3호
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• pp.209-217
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• 2008

A disease with mass mortality characterized exophthalmia and abdominal distension by ascites occurred in farmed starry flounder, Platichthys stellatus in Pohang since October of 2007. Severe necrosis and infiltration of inflammatory cells were observed in tissue histopathological sections from liver, kidney, spleen and heart of the diseased fish. The catalase-negative and gram positive cocci with -hemolysis were isolated from moribund fish. Analysis of the API profiles and the multiplex PCR of the isolates showed that strains were identified as Streptococcus parauberis. In API profiles, S. parauberis isolated from starry flounder differed from those of olive flounder, Paralichthys olivaceus to the test of arginine dihydrolase, D-mannitol, D-sorbitol and α-lactose. And the strains, PH0710 and PH0711, were strongly lethal for starry flounder (LD50 ranging from 4.2×103~4.2×102 cfu/fish at 7 days after intraperitoneally inoculation). This is the first report on a S. parauberis infection in starry flounder.

• 한국어병학회지
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• 제23권1호
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• pp.17-25
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• 2010

We have identified an iridovirus CH-1 from sea perch Lateolabrax sp. healthy externally and imported from China to Korea. In a comparison of the nucleotide sequences of the five different genomic regions, the CH-1 appears to be closely related to the ISKNV, IVS-1 and Ehime-1 strains detected in China, Korea and Japan respectively. In quantitative comparison of the viral DNA, level of CH-1 in tissue of imported fish was 10,000 times lower than that of IVS-1 strain presented in the infected rock bream Oplegnathus fasciatus of moribund stage. It allowed us to speculate the possibility of the asymtomatic iridovirus infection in the culturing sea perch. Such possibility of asymptomatic infection was supported by result of no appearance of dead fish with typical symptoms of iridoviral disease in keeping experiment of the imported sea pearch in laboratory for more than three weeks. Such asymptomatic infections with iridovirus were also found in spleen of the culturing and externally healthy sea perch of Korea by the presence of the iridoviral DNA in nested PCR.

• 한국수산과학회지
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• 제35권3호
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• pp.237-241
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• 2002

This study was performed both to explore the host of nervous necrosis virus (NNV) between mariculturing fish species and to examine the phylogenic position of the NNV in Korea. NNV was confirmed on the basis of histopathological and molecular biological examination, then VNN infection was Preyed from either moribund or dead fishes including red drum, Sciaenops ocellatus; oblong rock fish, Sebastes oblongus and flounder, Paralichthys olivaceus. As a result of sequencing for a part of ms, virus from red drum was showed $98\%, $97\%, $86\% and $74\% homology with oblong rock fish, grouper, Japanese flounder and striped jack, respectively. On the other hand, NNV from oblong rock fish was demonstrated $96\%, $85\% and $72\% homology with grouper, Japanese flounder and striped jack, respectively. NNV from red drum and oblong rock fish was exhibited phylogenically distant from the representative NNV, SJNNV originated from striped jack. On the contrary, the viruses appeared to be similar species with Taiwan NNV isolated from culturing grouper.

• 한국어병학회지
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• 제33권2호
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• pp.127-138
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• 2020

코끼리조개 성패 및 유생으로부터 잠재적 병원성 세균 분리 및 동정을 수행하였다. 분리된 균주는 분자생물학적 기법 및 생화학적 검사를 통해 동정하였으며, 명확한 동정 및 계통수 분석을 위해 16S rDNA와 하우스키핑 유전자 (pyrH, recA, rpoA)를 결합하여 분석하는 MLSA를 적용하였다. 총 141개의 균주가 분리되었으며, 건강한 성패에서는 10개, 수포 병변을 보이는 빈사 상태의 성패에서 52개, 유생에서 79개가 분리되었다. 이 중 빈사상태의 성패에서 46개, 유생에서 39개의 균주가 Vibrio 속 세균으로 동정되었으며, 나머지 균주들은 모두 일반해양세균으로 동정되었다. Vibrio 속 세균 중에서는 수포 병변을 보이는 성패에서 Vibrio splendidus가 가장 많이 분리되었으며 기존의 V. splendidus와 함께 동일한 클러스터를 형성하였다. 하지만, 인위감염실험을 실시하지 않았고 건강한 유생에서도 V. splendidus가 분리되어 성패에서 나타난 수포와 V. splendidus와의 관계는 확실하지 않으며, 차후 추가 연구가 필요할 것으로 생각된다.

• 한국어병학회지
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• 제5권2호
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• pp.61-75
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• 1992

틸라피아에 실험적으로 Edwardsiella tarda를 경구감염 시켰다. 틸라피아의 장을 자극시키지 않았을 때는 E. tarda가 감염되지 않았으나 과산화수소로 장을 자극시킨후 E. tarda를 투여하였더니 감염되었다. 150~200g되는 틸라피아 한마리에 $10^6CFU/m{\ell}$, $10^7CFU/m{\ell}$, $10^8CFU/m{\ell}$를 투여한 4일 후부터 죽은 실험어의 간장, 신장, 비장에 농창이 형성되었다. 또한 장관 장해부에서 세균이 증식되어 전신감염으로 급히 발병되어 죽은 예가 많았다. 자연감염어에서 볼 수 있는 증상이 나타났다.