• Title/Summary/Keyword: sevenband grouper

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Pathogenicity of the fish nodavirus causing viral nervous necrosis of sevenband grouper, Epinephelus septemfasciatus (능성어, Epinephelus septemfasciatus의 바이러스성 신경괴사증 바이러스의 병원성 연구)

  • Sohn, Sang-Gyu;Chun, Seh-Kyu
    • Journal of fish pathology
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    • v.12 no.2
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    • pp.107-113
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    • 1999
  • The pathogenicity of the fish nodavirus causing viral nervous necrosis (VNN) of sevenband grouper, Epinephelus septemfasciatus was examined in sevenband grouper and other marine fish by intramuscular injection. Sevenband groupers of 27~104 g in body weight were highly susceptible to the fish nodavirus, but yellowtail (537 g in body weight), red seabream (207 g), rock bream (43 g), flounder (41 g), tiger puffer (27 g) and rockfish (94 g) of the sizes used to this experiment were not. The pathogenicity of the viral agent to the sevenband grouper was high without regard to fish sizes at rearing water temperature over $20^{\circ}C$, but not at $15^{\circ}C$. Therefore, susceptibility of sevenband grouper to the viral agent causing VNN was thought to be water temperature-dependent rather than fish size (age-dependent). Compared to the infectivity of the viral agent to sevenband grouper with artificial infection methods, fish were successfully affected by intramuscular, intraperitoneal, oral, dipping and cohabitation administrations although there were slight differences in mortalities among infection methods. And survival sevenband grouper after infection with the fish nodavirus was resistant to the reinfection for a long time.

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Development of a Recombinant Protein Vaccine Based on Cell-Free Protein Synthesis for Sevenband Grouper Epinephelus septemfasciatus Against Viral Nervous Necrosis

  • Kim, Jong-Oh;Kim, Jae-Ok;Kim, Wi-Sik;Oh, Myung-Joo
    • Journal of Microbiology and Biotechnology
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    • v.25 no.10
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    • pp.1761-1767
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    • 2015
  • Sevenband grouper, Epinephelus septemfasciatus, is becoming an important aquaculture species in Korea. However, viral nervous necrosis disease is a large problem causing mass mortality in sevenband grouper aquaculture. Recombinant protein vaccines are one of the best methods to reduce these economic losses. However, the cell-based expression method mainly produces inclusion bodies and requires additional procedures. In this study, we expressed a recombinant viral coat protein of sevenband grouper nervous necrosis virus (NNV) using a cell-free protein synthesis system. The purified recombinant NNV coat protein (rNNV-CP) was injected into sevenband grouper at different doses followed by a NNV challenge. Nonimmunized fish in the first trial (20 μg/fish) began to die 5 days post-challenge and reached 70% cumulative mortality. In contrast, immunized fish also starting dying 5 days postchallenge but lower cumulative mortality (10%) was observed. Cumulative morality in the second trial with different doses (20, 4, and 0.8 μg/fish) was 10%, 40%, and 50%, respectively. These results suggest that rNNV-CP can effectively immunize sevenband grouper depending on the dose administered. This study provides a new approach to develop a recombinant vaccine against NNV infection for sevenband grouper.

Production of monoclonal antibodies to immunoglobulin M of sevenband grouper (Epinephelus septemfasciatus) (능성어(Epinephelus septemfasciatus) immunoglobulin M에 대한 단클론 항체 생산)

  • Kim, Si-Woo;Kim, Jong-Oh;Kong, Kyoung-Hui;Oh, Myung-Joo;Kim, Wi-Sik
    • Journal of fish pathology
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    • v.34 no.1
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    • pp.111-115
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    • 2021
  • Immunoglobulin M (IgM) of sevenband grouper (Epinephelus septemfasciatus) was purified by mannan-binding protein (MBP) affinity column. The purified IgM had an apparent molecular weights of 76 (heavy chain) and 28 (light chain) kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Eight hybridoma clones secreting monoclonal antibodies (mAbs) against sevenband grouper IgM were established. Antibody detection enzyme-linked immunosorbent assay (ELISA) with bovine serum albumin (BSA, antigen) and the 8 mAbs revealed that optical density (OD) values were clearly different between sera from BSA-immunization and non-immunization of sevenband grouper. These results suggest that the produced mAbs in this study are specifically reacted with IgM of sevenband grouper.

A basic study for the behaviour control of sevenband grouper, Epinephelus septem fasciatus, to underwater low frequency sound I. The Auditory thresholds of sevenband grouper (수중 저주파에 의한 능성어 (Epinephelus septem fasciatus)의 행동제어에 관한 기초적 연구 I. 능성어의 청각문턱치)

  • 양용수
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.35 no.4
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    • pp.391-396
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    • 1999
  • It is well known that fish hear a wide frequency range of sound using both laterial line and inner ear, and the sound is probably the most effective channel for long-range communication underwater than any other stimulus.The auditory threshold of svenband grouper, Epinephelus septem fasciatus was determined by conditioning method using a sound coupled with electric shock in a tank. The audio-signals and electric shock used in the experiment were pure tones of 100 to 1000Hz and DC 6n.The response of fish to the sound was observed by ECG intervals from precordial leads method (V1·V2 method). The auditory threshold curve for sevenband grouper was V-shaped, with most sensitive threshold at 350Hz in the range of 100~1000Hz. The Sevenband grouper were more sensitive to sounds of 200~400Hz than to adjacent frequencies.

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Studies on Cryopreservation of Sperm in Sevenband grouper, Epinephelus septemfasciatus and Kelp grouper, E. bruneus (능성어, Epinephelus septemfasciatus와 자바리, E. bruneus의 정자동결보존에 관한 연구)

  • Kim, Hyo Gun;Kim, Soo Chel;Kim, Doo Yong;Kim, Jung Woo;Kho, Kang Hee
    • Journal of Marine Life Science
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    • v.2 no.1
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    • pp.1-6
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    • 2017
  • The purpose of this research is to develop the simple freezing method for sperm cryopreservation in the Sevenband grouper and Kelp grouper. The motility and survival rate were checked to investigate the effects of diluent and cryoprotectant on sperm cryopreservation.In cryopreservation experiments, 300 mM glucose and 15% dimethyl sulfoxide (DMSO) were used as a diluent and a cryoprotectant, respectively. As a results of cryopreservation, the motility rate of Sevenband grouper was found to be more than 90%, and that of Kelp grouper was found to be more that 60% in sperm 5 months after cryopreservation.

Prevention Strategies for Viral Nervous Necrosis (VNN) in Sevenband Grouper Epinephelus septemfasciatus Aquaculture Farms (능성어(Epinephelus septemfasciatus) 양식장에서의 바이러스성신경괴사증(VNN) 예방대책)

  • Kim, Wi-Sik;Kim, Jong-Oh
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.4
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    • pp.403-410
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    • 2015
  • Viral nervous necrosis (VNN) is a serious disease of sevenband grouper Epinephelus septemfasciatus in Korean aquaculture farms. However, we suggest the following preventative methods for hatcheries: 1) disinfecting rearing water, 2) selecting spawners via ELISA and PCR, 3) selecting eggs via PCR, 4) disinfecting fertilized eggs, and 5) proper facilities management. When these methods are implemented, nervous necrosis virus (NNV)-free fish are produced because vertical and horizontal transmission is prevented. However, horizontal transmission of NNV through rearing seawater sourced from the environment during grow-out stages in sea cages can still occur. Live NNV vaccines with a low rearing temperature or Poly(I:C) immunization are very effective at preventing horizontal transmission of NNV in rearing farms. Furthermore, even after VNN is contracted, fish mortality can be reduced by administering Poly(I:C).

Reproductive Bioligy of the Sevenband Grouper, Epinephelus septemfasciatus I. The Effect of HCG on Ovulation Induction (능성어, Epinephelus septemfasciatus의 번식생물학적 연구 I. HCG 처리에 의한 배란유도)

  • Kim, Byong-Ho;Kim, Kyong-Min;Lee, Young-Don;Song, Choon Bok;Rho, Sum
    • Journal of Aquaculture
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    • v.10 no.1
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    • pp.55-61
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    • 1997
  • The experiment was conducted to understand the effect of HCG upon ovulation induction and egg maturation in the sevenband grouper, Epinephelus septemfasciatus, as a part of the research for its resources management and seed production. Three different size groups of sevenband groupers showing 300~400g, 1,500~2,000g and 2,500~4,000g, were collected from June to August, 1996. They were treated two or three times with HCG (500~1,000 IU/kg). Gonadal development of the sevenband groupers were examined using the paraffin section method and then stained with haematoxylin and eosin. When smaller groups of sevenband grouper having 300~400g, 1,500~2,00g and 2,500~3,200g in weight were treated two or three time with HCG 9500~1,000 IU/g), their gonads contained oogonia, oocytes with the size of 20~30${\mu}{\textrm}{m}$, and stroma tissues. However, in case of two HCG treatments with a dosage of 1,000 IU/kg on sevenband groupers of 3,400~4,000g, both healthy eggs of $800\mu$m in diameter and regressing eggs were ovulated. A sevenband grouper of 4,000g obvulated 4,252 eggs in total. Of these, healthy and regressing eggs turned out to be 20.8% and 79.2%, respectively. In addition, previtellogenic oocytes of around $50\mu$m, oocytes of 20~$30\mu$m, and ovulation trace were also observed in the gonad.

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A Fish Nodavirus Isolated from Cultured Sevenband Groupe, Epinephelus septemfasciatus (양식 능성어로 부터 Fish Nodavirus 분리)

  • Sohn, Sang-Gyu;Park, Myoung-Ae;Oh, Myung-Joo;Chun, Seh-Kyu
    • Journal of fish pathology
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    • v.11 no.2
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    • pp.97-104
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    • 1998
  • Since 1989, mass mortality has repeatly occurred in cage-cultured sevenband grouper, Epinephelus septemfasciatus along the southern coast of Korea in the summer season and usually reached over 80% within a few months. Diseased fish showed the clinical signs of anorexia, dark coloration, loss of eqilibrium, spinal swimming behaviour, vertebral deformity and inflation of swim bladder. Histopathologically, necrosis and/or vacuolation of the nerve cells in the brain and retina were observed. We previously reported that the causative agent was filtrable. The causative agent was not culturable in various fish cells; RTG-2, CHSE-214, BF-2, EPC and FHM. However, electron microscopic observation revealed unenveloped icosahedral viral particles with about 30 nm in diameter in the cytoplasm of nerve cells of the brain. The characteristics of the virus was tested by an artificial infection with the filtrate of the homogenate of diseased fish. The pathogenicity of the virus was retained after treatment with ether or heat ($50^{\circ}C$, 30 min) but partly lost by pH 3 or 11 treatment. These results suggest that the causative agent are similar to the fish nodavirus. In order to compare the causative agent with a fish nodavirus, Striped Jack Nervous Necrosis Virus (SJNNV), a polymerase chain reaction (PCR) was performed with primers specific to SJNNV. As a result, about 430 by PCR products were detected from the brain and the eye of both naturally and artificially infected sevenband grouper. All these results represent that the mass mortality in the cultured sevenband grouper is caused by the infection of a nodavirus similar to SJNNV and this is the first report of a fish nodavirus from the cultured sevenband grouper in Korea.

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Prevalence of viral nervous necrosis (VNN) in sevenband grouper Epinephelus septemfasciatus farms (능성어 양식장에서의 viral nervous necrosis (VNN) 발생양상)

  • Kim, Choon-Sup;Kim, Wi-Sik;Nishizawa, Toyohiko;Oh, Myung-Joo
    • Journal of fish pathology
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    • v.25 no.2
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    • pp.111-116
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    • 2012
  • Prevalence of viral nervous necrosis (VNN) in sevenband grouper Epinephelus septemfasciatus farms was investigated during the period of 2006-2008. The outbreak of the VNN was observed from August (water temperature: $24-26^{\circ}C$) to September or October ($20-25^{\circ}C$). The viral infection resulted in acute or chronic mortality of the host, where the mortality rate of juvenile fish was higher than that of the adult fish. Phylogenetic analysis based on partial RNA2 coat protein gene nucleotide sequences revealed that all the isolates from sevenband grouper were classified into the genotype redspotted grouper nervous necrosis virus (RGNNV). In conclusion, VNN of juvenile and adult sevenband groupers during the summer season (July to October, water temperature: about $24^{\circ}C$) was caused by virus belonging to the genotype RGNNV.

Ovulation Induction Effect of Sevenband Grouper, Epinephelus septemfasciatus by Treating Hormones (호르몬 처리에 의한 능성어 Epinephelus septemfasciatus의 배란유도 효과)

  • HONG, Chang-Gi;CHO, Jae-Kwon;PARK, Jong-Youn;SON, Maeng-Hyun;PARK, Jae-Min;HAN, Kyeong-Ho;KANG, Hee-Woong
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.4
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    • pp.981-989
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    • 2015
  • This study aims to investigate how ovulation induction of sevenband grouper, Epinephelus septemfasciatus varies when treated with different hormonal substances such as ovaprim, pimozide, LHRHa, and HCG. As for LHRHa, we injected it in different concentrations: $50{\mu}g/kg$, $100{\mu}g/kg$, $150{\mu}g/kg$, and $200{\mu}g/kg$. All hormonal substances including LHRHa were injected into back muscles. As a result, ovulation occurred in all sample groups. The sample group injected with HCG released the largest amount of eggs, and the dimeter of eggs and oil globules were also significantly bigger than those of others. Fertilization rate, embryonic survival rate, and hatching rate were the highest in a LHRHa ($100{\mu}g/kg$) +pimozide ($1,000{\mu}g/kg$) group and buoyant rate in a LHRHa group. Ovulation rate was 100% when LHRHa was injected in different concentrations. The largest amount of eggs was released in $200{\mu}g/kg$. The diameter of eggs and oil globules were the biggest in $200{\mu}g/kg$ and the smallest in $50{\mu}g/kg$. Fertilization rate showed no significant difference through all different levels of concentration: 94.6-95.3%. Buoyant rate was the highest in $100{\mu}g/kg$ and embryonic survival rate and hatching rate in $150{\mu}g/kg$. Based on these experimental results, we concluded that LHRHa in $100{\mu}g/kg$ is the most efficient for the ovulation induction of sevenband grouper.