• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.57-58
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• 2005

• Journal of fish pathology
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• v.17 no.3
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• pp.159-169
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• 2004

Bacterial wihte enteritis ocurred by infection of V. ichthyoenteri is a devastating disease in olive flounder (Paralichthys olivaceus) hatcheries in Korea. Since white enteritis has been a problem in aquqtic industries, necessity of a rapid detection method is increased. In an attempt to develop rapid PCR method the detection of V. ichthyoenteri, we examined the 16S-23S rRNA intergenic spacer region(ISR) of V. ichthyoenteri and developed species-specific primer for V. ichthyoenteri. The intergenic spacers were amplified by primers complementary to conserved region of 16S and 23S rRNA genes. The intergenic spacer region between the 16S and 23S rRNA genes of V. ichthoenteri were investigated by PCR fragment length typing and DNA sequencing. Analysis of the ISR sequences showed that V. ichthyoenteri contains one types of polymorphic ISRs. The size of ISRs ranged 348bp length and not contains tRNA genes. Mutiple alignment of representative sequences from different Vibrio species revealed several domains of high sequence variability, and allowed to design species-specific primer for detection of Vibrio ichthyoenteri. PCR. The specific of the primer was examined using genomic DNA prepared from 19 different Vibrio species, isolated 18group Vibrio species. The results showed that the PCR reaction using species-specific primer designed in this study can be used to detect V. ichthyoenteri.

• Journal of fish pathology
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• v.8 no.2
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• pp.99-109
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• 1995

The diseased larvae of the flounder, Paralichthys olivaceus, were sampled several times from a fish hatchery located in Cheju Island between December, 1991 and April, 1992. They turned out to be infected with Vibrio sp. and diagnosed as intestinal necrosis of flounder larvae(INFL) based on morphological, biological, and biochemical examinations. INFL was known to be caused by the live food organism infected with Vibrio sp. The optimal growth conditions of the isolates for temperature, pH, and NaCl concentration were $20\sim30^{\circ}C$, 6~8, and 2~4%, respectively. In the drug sensitivity test, the isolates were sensitive to oxytetracycline, nalidixic acid, kanamycin, and novobiocin, but resistant to ampicillin, erythromycin, spiramycin and sulfa-drug.

• Journal of fish pathology
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• v.19 no.2
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• pp.127-139
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• 2006

From 2002 to 2004, various vibrios were isolated from the olive flounder, Paralichthys olivaceus of culturing size with disease signs. During this survey, it was known that the high proportion of Vibrio ichthyoenteri was occupied among the isolated vibrios. Generally, V. ichthyoenteri is well known as the pathogen of bacterial enteritis of olive flounder larvae. The aim of the present study was the compare the characteristics of two groups of V. ichthyoenteri, culturing sized olive flounder, and larvae of olive flounder showing the intestinal necrosis. The research was focused on the physiology, biochemistry, genetics in the two bacterial groups. The physiological and biochemical characteristics of the tested strains were very similar. The intergenic spacer (IGS) region between the 16S and 23S rRNA genes of 21 isolated strains and 3 reference strains, V. ichthyoenteri, were investigated by PCR fragment length typing and DNA sequencing. After the isolated strains were identified as V. ichthyoenteri, not only phenotypic characteristics of the isolated and reference strains but also homology of 16S-23S IGS of all isolated strains and reference strains as 99.1~100%. The V. ichthyoenteri showed 4 specific 16S-23S patterns and contained no-tRNA, tRNAGlu(TTC) , tRNAIle(GAT) tRNAAla(TGC) type .

• Journal of fish pathology
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• v.26 no.3
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• pp.207-217
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• 2013

Recently high mortality of cultured olive flounder, Paralichthys olivaceus occurred frequently at the fish farms in Ulsan, Korea. The diseased fish showed skinny body and swimming behavior around the water surface with liver atrophy and white enteritis as internal signs. The isolated bacteria were identified to V. scophthalmi by biochemical test, nucleotide analysis of 16S rRNA and dnaJ gene sequencing. The pathogen of this study showed strong pathogenicity as 75% mortality to olive flounder by intraperitoneal injection of $1{\times}10^6$ CFU/fish. The pathological sign was not different between the naturally diseased fish and the artificially infected fish. Histopathological changes were shown to liver atrophy, desquamation of the intestinal mucosa and hyaline droplet like as other previous studies.