To evaluate the effects of duck hepatitis virus-1 （DHV-1） on the body weight gain in duck and the effects of silymarin on it in vivo, 100 10-d-old ducks, both male and female, were collected to be subjected to the t...To evaluate the effects of duck hepatitis virus-1 （DHV-1） on the body weight gain in duck and the effects of silymarin on it in vivo, 100 10-d-old ducks, both male and female, were collected to be subjected to the test. The experiments were conducted in 8 groups： in group 1-3, the animals were inoculated with 1：105 diluted duck hepatitis virus （DHV-1） infected allantoic fluid and given 0, 30, and 50 mg kg^-1 BW d^-1 silymarin orally, respectively. In group 4-6, the animals were inoculated with 1：5 × 105 diluted DHV-1 infected allantoic fluid and given 0, 10, and 30 mg kg^-1 BW d^-1 silymarin orally, respectively. In group 7, the animals were given 10 mg kg^-1 BW d^-1 silymafin only. Group 8 was the control one treated by injecting sterillized saline into the leg muscles. All the silymarin was given from 0 to 4 d after inoculation of the virus. By the 5th d after inoculation, the vein blood was drawn from the dorsal foot vein and the plasma samples were collected and stored at -20℃. The body weight gain （BWG） was measured from 0 to 10 d after inoculation. The plasma IGF-I, T3, and T4 concentrations were measured by radioimmunoassay （RIA）. At the virus dose of 1：5 ×105 diluted virus infected allantoic fluid, the inoculation of the virus enhanced the BWG significantly compared with that of the control （P〈 0.01）, while 10-50 mg kg^-1 BW d^-1 silymarin could counteract the effects of the virus on the BWG dose-dependently. The plasma IGF-I levels showed no correlation with the BWG, but the T3 levels showed a same tropism with the body weight gain. The present results indicated that sublethal DHV-1 enhanced the body weight gain of ducklings significantly, and the silymarin could counteract this effect in vivo.展开更多
The complete genomic sequence of Duck hepatitis virus 1(DHV-1) ZJ-V isolate was sequenced and determined to be 7 691 nucleotides(nt) in length with a 5'-terminal un-translated region(UTR) of 626 nt and a 3'-te...The complete genomic sequence of Duck hepatitis virus 1(DHV-1) ZJ-V isolate was sequenced and determined to be 7 691 nucleotides(nt) in length with a 5'-terminal un-translated region(UTR) of 626 nt and a 3'-terminal UTR of 315 nt(not including the poly(A) tail).One large open reading frame(ORF) was found within the genome(nt 627 to 7 373) coding for a polypeptide of 2 249 amino acids.Our data also showed that the poly(A) tail of DHV-1 has at least 22 A's.Sequence comparison revealed significant homology(from 91.9% to 95.7%) between the protein sequences of the ZJ-V isolate and those of 21 reference isolates.Although DHV-1 has been classified as an unassigned virus in the Picornaviridae family,its genome showed some unique characteristics.DHV-1 contains 3 copies of the 2A gene and only 1 copy of the 3B gene,and its 3'-NCR is longer than those of other picornaviruses.Phylogenetic analysis to do sequence homology based on the VP1 protein sequences showed that the ZJ-V isolate shares high sequence homology with the reported DHV-1 isolates(from 92.9% to 99.2%),indicating that DHV-1 is genetically stable.展开更多
Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds.All members of this family can cause acute and chronic hepatic infec-tio...Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds.All members of this family can cause acute and chronic hepatic infec-tion,which in the case of human hepatitis B virus(HBV) constitutes a major global health problem.Although our knowledge about the molecular biology of these highly liver-specific viruses has profoundly increased in the last two decades,the mechanisms of attachment and productive entrance into the differentiated host hepa-tocytes are still enigmatic.The difficulties in studying hepadnaviral entry were primarily caused by the lack of easily accessible in vitro infection systems.Thus,for more than twenty years,differentiated primary hepato-cytes from the respective species were the only in vitro models for both orthohepadnaviruses(e.g.HBV) and avihepadnaviruses(e.g.duck hepatitis B virus [DHBV]).Two important discoveries have been made recently re-garding HBV:(1) primary hepatocytes from tree-shrews;i.e.,Tupaia belangeri,can be substituted for primary hu-man hepatocytes,and(2) a human hepatoma cell line(HepaRG) was established that gains susceptibility for HBV infection upon induction of differentiation in vitro.A number of potential HBV receptor candidates have been described in the past,but none of them have been confirmed to function as a receptor.For DHBV and prob-ably all other avian hepadnaviruses,carboxypeptidase D(CPD) has been shown to be indispensable for infection,although the exact role of this molecule is still under debate.While still restricted to the use of primary duck hepatocytes(PDH),investigations performed with DHBV provided important general concepts on the first steps of hepadnaviral infection.However,with emerging dataobtained from the new HBV infection systems,the hope that DHBV utilizes the same mechanism as HBV only partially held true.Nevertheless,both HBV and DHBV in vitro infection systems will help to:(1) functionally dis-sect the hepadnaviral entry pathways,(2) perform re-verse genetics(e.g.test the fitness of escape mutants),(3) titrate and map neutralizing antibodies,(4) improve current vaccines to combat acute and chronic infections of hepatitis B,and(5) develop entry inhibitors for future clinical applications.展开更多
基金supported by the National Natural Science Foundation of China (30571341)Foshan Science and Technology Development Programme,China(04040111)
文摘To evaluate the effects of duck hepatitis virus-1 （DHV-1） on the body weight gain in duck and the effects of silymarin on it in vivo, 100 10-d-old ducks, both male and female, were collected to be subjected to the test. The experiments were conducted in 8 groups： in group 1-3, the animals were inoculated with 1：105 diluted duck hepatitis virus （DHV-1） infected allantoic fluid and given 0, 30, and 50 mg kg^-1 BW d^-1 silymarin orally, respectively. In group 4-6, the animals were inoculated with 1：5 × 105 diluted DHV-1 infected allantoic fluid and given 0, 10, and 30 mg kg^-1 BW d^-1 silymarin orally, respectively. In group 7, the animals were given 10 mg kg^-1 BW d^-1 silymafin only. Group 8 was the control one treated by injecting sterillized saline into the leg muscles. All the silymarin was given from 0 to 4 d after inoculation of the virus. By the 5th d after inoculation, the vein blood was drawn from the dorsal foot vein and the plasma samples were collected and stored at -20℃. The body weight gain （BWG） was measured from 0 to 10 d after inoculation. The plasma IGF-I, T3, and T4 concentrations were measured by radioimmunoassay （RIA）. At the virus dose of 1：5 ×105 diluted virus infected allantoic fluid, the inoculation of the virus enhanced the BWG significantly compared with that of the control （P〈 0.01）, while 10-50 mg kg^-1 BW d^-1 silymarin could counteract the effects of the virus on the BWG dose-dependently. The plasma IGF-I levels showed no correlation with the BWG, but the T3 levels showed a same tropism with the body weight gain. The present results indicated that sublethal DHV-1 enhanced the body weight gain of ducklings significantly, and the silymarin could counteract this effect in vivo.
基金National Natural Science Foundation of China (30670074)
文摘The complete genomic sequence of Duck hepatitis virus 1(DHV-1) ZJ-V isolate was sequenced and determined to be 7 691 nucleotides(nt) in length with a 5'-terminal un-translated region(UTR) of 626 nt and a 3'-terminal UTR of 315 nt(not including the poly(A) tail).One large open reading frame(ORF) was found within the genome(nt 627 to 7 373) coding for a polypeptide of 2 249 amino acids.Our data also showed that the poly(A) tail of DHV-1 has at least 22 A's.Sequence comparison revealed significant homology(from 91.9% to 95.7%) between the protein sequences of the ZJ-V isolate and those of 21 reference isolates.Although DHV-1 has been classified as an unassigned virus in the Picornaviridae family,its genome showed some unique characteristics.DHV-1 contains 3 copies of the 2A gene and only 1 copy of the 3B gene,and its 3'-NCR is longer than those of other picornaviruses.Phylogenetic analysis to do sequence homology based on the VP1 protein sequences showed that the ZJ-V isolate shares high sequence homology with the reported DHV-1 isolates(from 92.9% to 99.2%),indicating that DHV-1 is genetically stable.
基金Supported by grant SFB535/A2 from DFG, EU QLK 2000- 01476 and DFG UR72/1-3, UR72/1-4
文摘Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds.All members of this family can cause acute and chronic hepatic infec-tion,which in the case of human hepatitis B virus(HBV) constitutes a major global health problem.Although our knowledge about the molecular biology of these highly liver-specific viruses has profoundly increased in the last two decades,the mechanisms of attachment and productive entrance into the differentiated host hepa-tocytes are still enigmatic.The difficulties in studying hepadnaviral entry were primarily caused by the lack of easily accessible in vitro infection systems.Thus,for more than twenty years,differentiated primary hepato-cytes from the respective species were the only in vitro models for both orthohepadnaviruses(e.g.HBV) and avihepadnaviruses(e.g.duck hepatitis B virus [DHBV]).Two important discoveries have been made recently re-garding HBV:(1) primary hepatocytes from tree-shrews;i.e.,Tupaia belangeri,can be substituted for primary hu-man hepatocytes,and(2) a human hepatoma cell line(HepaRG) was established that gains susceptibility for HBV infection upon induction of differentiation in vitro.A number of potential HBV receptor candidates have been described in the past,but none of them have been confirmed to function as a receptor.For DHBV and prob-ably all other avian hepadnaviruses,carboxypeptidase D(CPD) has been shown to be indispensable for infection,although the exact role of this molecule is still under debate.While still restricted to the use of primary duck hepatocytes(PDH),investigations performed with DHBV provided important general concepts on the first steps of hepadnaviral infection.However,with emerging dataobtained from the new HBV infection systems,the hope that DHBV utilizes the same mechanism as HBV only partially held true.Nevertheless,both HBV and DHBV in vitro infection systems will help to:(1) functionally dis-sect the hepadnaviral entry pathways,(2) perform re-verse genetics(e.g.test the fitness of escape mutants),(3) titrate and map neutralizing antibodies,(4) improve current vaccines to combat acute and chronic infections of hepatitis B,and(5) develop entry inhibitors for future clinical applications.
