The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Hyun Do Jeong - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of megalocytivirus transmission between bivalve molluscs and rock Bream Oplegnathus fasciatus
Aquaculture, 2014Co-Authors: Ji Woong Jin, Kwang Il Kim, Joong Kyun Kim, Nam Gyu Park, Hyun Do JeongAbstract:Abstract Megalocytivirus is a major viral agent that affects fresh and marine fish, and causes serious economic losses in aquaculture in Asian countries. As filter-feeding organisms, bivalve molluscs may act as viral transmitters following the capture of a released virus into seawater from infected fish. We identified megalocytivirus, rock Bream iridovirus (RBIV) type in Pacific oysters (Crassostrea gigas) and blue mussels (Mytilus edulis) inhabiting the areas around rock Bream farms in Korea. In artificial viral-depuration analysis, the concentration of iridovirus Sachun (IVS) particles, which is a major RBIV strain in Korea, decreased more rapidly in seawater than in the digestive glands of mussels. Cohabitation of mussels with IVS-infected rock Bream (Oplegnathus fasciatus) resulted in the presence of viral particles in the gill, mantle and digestive gland of the mussels. In addition, the virus was retained in the digestive gland for 28 days, regardless of water temperature. Infection with IVS derived from the digestive gland of cohabitating mussels also led to 100% cumulative mortality in rock Breams. In this study, we investigated megalocytivirus carried by bivalve molluscs inhabiting the vicinity of rock Bream farms, and revealed the potential risk posed by these viral particles by modelling the cohabitation of mussels with RBIV-infected rock Bream.
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Quantitative analysis of the clinical signs in marine fish induced by Megalocytivirus infection
Journal of fish pathology, 2011Co-Authors: Ji Woong Jin, Kwang Il Kim, Joon Bum Jeong, Hye-jin Cho, Gyeong-hyun Park, Hyun Do JeongAbstract:In quantitative studies of clinical signs, rock Bream of adults and juveniles infected with Megalocytivirus IVS-1 isolated from rock Bream (Oplegnathus fasciatus) in Korea showed average and of spleen index respectively. In challenge experiments, Megalocytivirus IVS-1 induced 100% cumulative mortality in both adult and juvenile rock Bream. However we found 60% cumulative mortality in juvenile red sea Bream (Pagrus major) even after 30 days of injection, which contradicted with the results of other laboratories. Interestingly, IVS-1 infected red sea Bream of the same juvenile size with rock Bream showed lower spleen index compared to that of rock Bream. In real-time PCR, there was continuous increasing of the numbers of viral copies ( copies/mg) in the spleen of juvenile rock Bream infected, which were different from those in adult rock Bream showing plateau level after reaching to the peak level. Moreover, enlarged cell numbers in the infected spleen were also increased continuously in the juvenile but not in adult of rock Bream, even decreased after reaching to peak level. Consequently, significant differences in clinical signs: cumulative mortality. spleen index and viral copy number were found between rock Bream and red sea Bream, but not between adult and juvenile rock Bream. Certainly quantitative expression of clinical sign as in this study may be a way to compare the progression of megalocitiviral disease more accurately in different species or physiological conditions.
A M Polzonetti-magni - One of the best experts on this subject based on the ideXlab platform.
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Hormonal mechanisms regulating hepatic vitellogenin synthesis in the gilthead sea Bream, Sparus aurata.
American journal of physiology. Cell physiology, 2002Co-Authors: G Mosconi, O Carnevali, H R Habibi, R Sanyal, A M Polzonetti-magniAbstract:Experiments were carried out to study in vitro the effects of 17beta-estradiol (E(2)), homologous pituitary homogenate (HPH), and recombinant red sea Bream growth hormone (sbGH) on vitellogenin (VTG) secretion from cultured sea Bream liver fragments. Basal secretion of VTG was found to be significantly higher in the prespawning period, compared with sea Bream liver in the spawning and postspawning periods. Similarly, the sea Bream liver obtained during the prespawning period responded more significantly to treatments with E(2), HPH, or sbGH compared with sea Bream liver during spawning. In the postspawning period, treatments with E(2), HPH, or sbGH were without significant effect on VTG secretion level in sea Bream liver. The level of E(2) receptors was also analyzed by Western blot analysis. The result demonstrates a significantly higher level of E(2) receptors in the sea Bream liver at the prespawning stage compared with those at the spawning and postspawning stages. The findings support the hypothesis that homologous upregulation of estrogen receptors plays an important role in the estrogen-sensitive control of VTG synthesis in the sea Bream liver.
Ki Hong Kim - One of the best experts on this subject based on the ideXlab platform.
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Pathogenicity of marine birnavirus (MABV) on fingerlings of rock Bream (Oplegnathus fasciatus)
Aquaculture, 2007Co-Authors: Hyoung Jun Kim, Ryun Kwon, Eun Hye Lee, Yoon Kwon Nam, Sung Koo Kim, Ki Hong KimAbstract:To investigate the pathogenicity of marine birnavirus (MABV) on rock Bream (Oplegnathus fasciatus), two different sized rock Bream fingerlings were artificially infected with MABV. The experimental MABV strain previously isolated from asymptomatic olive flounder (Paralichthys olivaceus), was not pathogenic for olive flounder. Experimental infection of rock Bream fingerlings with the virus elicited typical signs of birnaviral disease and yielded high cumulative mortality. The presence of MABV in infected rock Bream fingerlings was confirmed by electron microscopy. These results indicate that rock Bream is susceptible to MABV isolated from asymptomatic olive flounder. There were no differences in gene sequence encoding VP5-pVP2 region between the viruses isolated from diseased rock Bream and the virus cultured in fish cell line. These results indicate that the virulence of the present MABV strain is variable according to host fish species, and the gene sequence encoding VP5-pVP2 region is not related at least by itself to the susceptibility of rock Bream to the disease caused by the present MABV strain.
Liu Guangxu - One of the best experts on this subject based on the ideXlab platform.
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Seawater carbonate chemistry and foraging behavior of Acanthopagrus schlegelii
PANGAEA, 2019Co-Authors: Rong Jiahuan, Su Wenhao, Guan Xiaofan, Shi Wei, Zha Shanjie, He Maolong, Wang Haifeng, Liu GuangxuAbstract:In recent years, ocean acidification (OA) caused by oceanic absorption of anthropogenic carbon dioxide (CO2) has drawn worldwide concern over its physiological and ecological effects on marine organisms. However, the behavioral impacts of OA and especially the underlying physiological mechanisms causing these impacts are still poorly understood in marine species. Therefore, in the present study, the effects of elevated pCO2 on foraging behavior, in vivo contents of two important neurotransmitters, and the expression of genes encoding key modulatory enzymes from the olfactory transduction pathway were investigated in the larval black sea Bream. The results showed that larval sea Breams (length of 4.71 +- 0.45 cm) reared in pCO2 acidified seawater (pH at 7.8 and 7.4) for 15 days tend to stall longer at their acclimated zone and swim with a significant slower velocity in a more zigzag manner toward food source, thereby taking twice the amount of time than control (pH at 8.1) to reach the food source. These findings indicate that the foraging behavior of the sea Bream was significantly impaired by ocean acidification. In addition, compared to a control, significant reductions in the in vivo contents of gama-aminobutyric acid (GABA) and Acetylcholine (ACh) were detected in ocean acidification-treated sea Breams. Furthermore, in the acidified experiment groups, the expression of genes encoding positive regulators, the olfaction-specific G protein (Golf) and the G-protein signaling 2 (RGS2) and negative regulators, the G protein-coupled receptor kinase (GRK) and arrestin in the olfactory transduction pathway were found to be significantly suppressed and up-regulated, respectively. Changes in neurotransmitter content and expression of olfactory transduction related genes indicate a significant disruptive effect caused by OA on olfactory neural signal transduction, which might reveal the underlying cause of the hampered foraging behavior
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ocean acidification impairs foraging behavior by interfering with olfactory neural signal transduction in black sea Bream acanthopagrus schlegelii
Frontiers in Physiology, 2018Co-Authors: Rong Jiahuan, Su Wenhao, Guan Xiaofan, Shi Wei, Zha Shanjie, He Maolong, Wang Haifeng, Liu GuangxuAbstract:In recent years, ocean acidification (OA) caused by oceanic absorption of anthropogenic carbon dioxide (CO2) has drawn worldwide concern over its physiological and ecological effects on marine organisms. However, the behavioral impacts of OA and especially the underlying physiological mechanisms causing these impacts are still poorly understood in marine species. Therefore, in the present study, the effects of elevated pCO2 on foraging behavior, in vivo contents of two important neurotransmitters, and the expression of genes encoding key modulatory enzymes from the olfactory transduction pathway were investigated in the larval black sea Bream. The results showed that larval sea Breams (length of 4.71 ± 0.45 cm) reared in pCO2 acidified seawater (pH at 7.8 and 7.4) for 15 days tend to stall longer at their acclimated zone and swim with a significant slower velocity in a more zigzag manner toward food source, thereby taking twice the amount of time than control (pH at 8.1) to reach the food source. These findings indicate that the foraging behavior of the sea Bream was significantly impaired by ocean acidification. In addition, compared to a control, significant reductions in the in vivo contents of γ-aminobutyric acid (GABA) and Acetylcholine (ACh) were detected in ocean acidification-treated sea Breams. Furthermore, in the acidified experiment groups, the expression of genes encoding positive regulators, the olfaction-specific G protein (Golf) and the G-protein signaling 2 (RGS2) and negative regulators, the G protein-coupled receptor kinase (GRK) and arrestin in the olfactory transduction pathway were found to be significantly suppressed and up-regulated, respectively. Changes in neurotransmitter content and expression of olfactory transduction related genes indicate a significant disruptive effect caused by OA on olfactory neural signal transduction, which might reveal the underlying cause of the hampered foraging behavior.
Ji Woong Jin - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of megalocytivirus transmission between bivalve molluscs and rock Bream Oplegnathus fasciatus
Aquaculture, 2014Co-Authors: Ji Woong Jin, Kwang Il Kim, Joong Kyun Kim, Nam Gyu Park, Hyun Do JeongAbstract:Abstract Megalocytivirus is a major viral agent that affects fresh and marine fish, and causes serious economic losses in aquaculture in Asian countries. As filter-feeding organisms, bivalve molluscs may act as viral transmitters following the capture of a released virus into seawater from infected fish. We identified megalocytivirus, rock Bream iridovirus (RBIV) type in Pacific oysters (Crassostrea gigas) and blue mussels (Mytilus edulis) inhabiting the areas around rock Bream farms in Korea. In artificial viral-depuration analysis, the concentration of iridovirus Sachun (IVS) particles, which is a major RBIV strain in Korea, decreased more rapidly in seawater than in the digestive glands of mussels. Cohabitation of mussels with IVS-infected rock Bream (Oplegnathus fasciatus) resulted in the presence of viral particles in the gill, mantle and digestive gland of the mussels. In addition, the virus was retained in the digestive gland for 28 days, regardless of water temperature. Infection with IVS derived from the digestive gland of cohabitating mussels also led to 100% cumulative mortality in rock Breams. In this study, we investigated megalocytivirus carried by bivalve molluscs inhabiting the vicinity of rock Bream farms, and revealed the potential risk posed by these viral particles by modelling the cohabitation of mussels with RBIV-infected rock Bream.
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Quantitative analysis of the clinical signs in marine fish induced by Megalocytivirus infection
Journal of fish pathology, 2011Co-Authors: Ji Woong Jin, Kwang Il Kim, Joon Bum Jeong, Hye-jin Cho, Gyeong-hyun Park, Hyun Do JeongAbstract:In quantitative studies of clinical signs, rock Bream of adults and juveniles infected with Megalocytivirus IVS-1 isolated from rock Bream (Oplegnathus fasciatus) in Korea showed average and of spleen index respectively. In challenge experiments, Megalocytivirus IVS-1 induced 100% cumulative mortality in both adult and juvenile rock Bream. However we found 60% cumulative mortality in juvenile red sea Bream (Pagrus major) even after 30 days of injection, which contradicted with the results of other laboratories. Interestingly, IVS-1 infected red sea Bream of the same juvenile size with rock Bream showed lower spleen index compared to that of rock Bream. In real-time PCR, there was continuous increasing of the numbers of viral copies ( copies/mg) in the spleen of juvenile rock Bream infected, which were different from those in adult rock Bream showing plateau level after reaching to the peak level. Moreover, enlarged cell numbers in the infected spleen were also increased continuously in the juvenile but not in adult of rock Bream, even decreased after reaching to peak level. Consequently, significant differences in clinical signs: cumulative mortality. spleen index and viral copy number were found between rock Bream and red sea Bream, but not between adult and juvenile rock Bream. Certainly quantitative expression of clinical sign as in this study may be a way to compare the progression of megalocitiviral disease more accurately in different species or physiological conditions.