Over the past five years, an epidemic disease broke out in Pelteobagrus fulvidraco ponds of Zhejiang Province. The diseased fish mainly exhibits head splitting and surface bleeding; dissection results reveal hepatonep...Over the past five years, an epidemic disease broke out in Pelteobagrus fulvidraco ponds of Zhejiang Province. The diseased fish mainly exhibits head splitting and surface bleeding; dissection results reveal hepatonephromegaly and abdominal bleeding. A bacterial strain HSY201301 was isolated from the liver tissue of P. fulvidraco with typical symptoms. Artificial infection experiment confirmed that the isolated strain had a strong virulence to healthy P. fidvidraco, leading to similar symptoms to naturally infected P. fulvidraco. The isolated strain was identified as an Edwardsiella tarda strain according to conventional morphological, physiological, biochemical characteristics and 16S rRNA gene sequence. Results of drug susceptibility test indicated that the isolated strain was sensitive to cipro- floxacin, doxitard, penicillin, doxycycline, and rocephin. This study laid solid foundation for effective prevention and control of E. tarda.展开更多
Trionyx sinensis Hemorrhagic Syndrome Virus(TSHSV)is an arterivirus newly discovered in Chinese softshell turtles.Little is known about the effect of antibodies against the virus or the distribution of the virus in di...Trionyx sinensis Hemorrhagic Syndrome Virus(TSHSV)is an arterivirus newly discovered in Chinese softshell turtles.Little is known about the effect of antibodies against the virus or the distribution of the virus in different organs of infected turtles.In this study,a partial protein of TSHSV-HP4 was produced using a prokaryotic expression system,and its polyclonal antibody was generated.The polyclonal antibody was confirmed by western blot and dot enzyme-linked immunosorbent assay(dot-ELISA).The distribution of TSHSV in different organs of T.sinensis was examined by immunohistochemistry(IHC)and the expression of immune-related genes was analyzed using quantitative real-time polymerase chain reaction(qRT-PCR).The results indicated that the recombinant TSHSV-HP4 protein was successfully expressed,and the generated polyclonal antibody showed specific binding to viral particles in the lung tissues of infected turtles.The IHC assay indicated that the virus was highly localized in various cells,including intestinal lymphocytes,enterocytes,kidney epithelial cells,spleen cells,lung macrophages,and cardiomyocytes.The qRT-PCR analysis revealed that TSHSV was detected in all organs tested,including the lungs,liver,kidneys,spleen,and heart.The numbers of viral mRNA copies in lung and heart tissues were significantly higher in the virus-antibody group than in the virus group.The interferonstimulated genes(ISGs),myxovirus resistance protein 2(MX2)and radical S-adenosyl methionine domain containing 2(RSAD2)were highly upregulated in all groups of infected turtles.Antibody-dependent enhancement(ADE)seemed to occur after stimulation by the polyclonal antibody,because significantly greater expression of the two genes was detected in the virus-antibody group than in the virus group.Overall,these results are important in understanding the cell localization of TSHSV and the immune response of infected turtles.展开更多
文摘Over the past five years, an epidemic disease broke out in Pelteobagrus fulvidraco ponds of Zhejiang Province. The diseased fish mainly exhibits head splitting and surface bleeding; dissection results reveal hepatonephromegaly and abdominal bleeding. A bacterial strain HSY201301 was isolated from the liver tissue of P. fulvidraco with typical symptoms. Artificial infection experiment confirmed that the isolated strain had a strong virulence to healthy P. fidvidraco, leading to similar symptoms to naturally infected P. fulvidraco. The isolated strain was identified as an Edwardsiella tarda strain according to conventional morphological, physiological, biochemical characteristics and 16S rRNA gene sequence. Results of drug susceptibility test indicated that the isolated strain was sensitive to cipro- floxacin, doxitard, penicillin, doxycycline, and rocephin. This study laid solid foundation for effective prevention and control of E. tarda.
基金supported by the Zhejiang Provincial Science and Technology Program(Nos.2020YSZX003 and 2020YSZX010)the Zhejiang Provincial Science Exploratory Program(No.2019TSX01),China。
文摘Trionyx sinensis Hemorrhagic Syndrome Virus(TSHSV)is an arterivirus newly discovered in Chinese softshell turtles.Little is known about the effect of antibodies against the virus or the distribution of the virus in different organs of infected turtles.In this study,a partial protein of TSHSV-HP4 was produced using a prokaryotic expression system,and its polyclonal antibody was generated.The polyclonal antibody was confirmed by western blot and dot enzyme-linked immunosorbent assay(dot-ELISA).The distribution of TSHSV in different organs of T.sinensis was examined by immunohistochemistry(IHC)and the expression of immune-related genes was analyzed using quantitative real-time polymerase chain reaction(qRT-PCR).The results indicated that the recombinant TSHSV-HP4 protein was successfully expressed,and the generated polyclonal antibody showed specific binding to viral particles in the lung tissues of infected turtles.The IHC assay indicated that the virus was highly localized in various cells,including intestinal lymphocytes,enterocytes,kidney epithelial cells,spleen cells,lung macrophages,and cardiomyocytes.The qRT-PCR analysis revealed that TSHSV was detected in all organs tested,including the lungs,liver,kidneys,spleen,and heart.The numbers of viral mRNA copies in lung and heart tissues were significantly higher in the virus-antibody group than in the virus group.The interferonstimulated genes(ISGs),myxovirus resistance protein 2(MX2)and radical S-adenosyl methionine domain containing 2(RSAD2)were highly upregulated in all groups of infected turtles.Antibody-dependent enhancement(ADE)seemed to occur after stimulation by the polyclonal antibody,because significantly greater expression of the two genes was detected in the virus-antibody group than in the virus group.Overall,these results are important in understanding the cell localization of TSHSV and the immune response of infected turtles.
