Duck hepatitis B virus (DHBV) belongs to the Avihepadnavirus genus of the Hepadnaviridae, and it not only has the same replication pattern, but also has the similar genomic and antigenic structures to Hepatitis B virus (HBV). The genome of DHBV is a partially double-stranded closed circular DNA. The genome consists of three distinct open reading frames (ORFs): ORF-PreS/S, ORF-PreC/C and ORF-P, which all locate on the negative DNA strand and encode four separate proteins. The ORF-PreS/S encodes envelope proteins L and S, and the ORF-PreC/C and ORF-P encode capsid proteins C and polymerase proteins P, respectively. The characteristics of genome structure,viral proteins features and functions were described in this review in order to provide useful information for the further study of DHBV and the duck model infected by DHBV.
Animals ; Ducks ; Hepadnaviridae Infections ; veterinary ; virology ; Hepatitis B Virus, Duck ; chemistry ; genetics ; isolation & purification ; Hepatitis, Viral, Animal ; virology ; Open Reading Frames ; Protein Structure, Tertiary ; Viral Proteins ; chemistry ; genetics

<b>BACKGROUNDb>To determine the feasibility of inhibition of duck hepatitis B virus (DHBV) DNA replication by antisense phosphorothioate oligodeoxynucleotides corresponding to DHBV transcription region.

<b>METHODSb>The authors designed three antisense phosphorothioate oligodeoxynucleotides which correspond to DHBV PreS1,PreS2 and S antigen gene promotors respectively. The DNA replication level was detected with Southern blot method and cpm calculation.

<b>RESULTSb>Primary duck hepatocyte culture was treated with 1.5 micromol/L antisense oligodeoxynucleotides in vitro, all the antisense fragments caused a firm inhibition of viral DNA replication and the inhibition rates were 61.5%, 69.3% and 62.4%, respectively. In vivo, the animals were treated with 10 microgram/g PreS1 antigen gene promotor antisense oligodeoxynucleotides per day for 6 days and a very strong inhibition rate of 87.9% was obtained.

<b>CONCLUSIONSb>The results demonstrated the potential clinical application of antisense phosphorothioate oligodeoxynucleotides in clinics.

Animals ; DNA Replication ; drug effects ; DNA, Viral ; drug effects ; Ducks ; Hepadnaviridae Infections ; virology ; Hepatitis B Surface Antigens ; blood ; Hepatitis B Virus, Duck ; genetics ; physiology ; Hepatitis, Viral, Animal ; virology ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; Protein Precursors ; blood ; Virus Replication ; drug effects

The aim of this study is to investigate the effect of hyperin on the cccDNA of duck hepatitis B virus and its immunological regulation. Duck hepatitis B virus (DHBV) infection model and normal mouse spleen lymphocyte were used to evaluate the anti-HBV and immunoregulation effects. The DHBV-DNA of serum was detected at different time points by using serum DOT-BLOT hybridization. Polymerase chain reaction (PCR) was used for the determination of nuclear covalent closed circular DNA (cccDNA). Cytokine secretion was determined by ELISA method. DHBV-DNA were inhibited by hyperin (25 or 50 mg x kg(-1)), while cccDNA of liver could be eliminated efficiently by hyperin (25 or 50 mg x kg(-1), P < 0.05, P < 0.01). The T helper 1 effector cytokine was markedly enhanced by hyperin (25 or 50 microg x mL(-1), P < 0.01). In conclusion, hyperin has anti-HBV activity via multiple targets and pathways, and cccDNA may be one of the important targets.
Animals ; Antiviral Agents ; pharmacology ; DNA, Circular ; metabolism ; DNA, Viral ; metabolism ; Hepadnaviridae Infections ; virology ; Hepatitis B Virus, Duck ; genetics ; Hepatitis, Viral, Animal ; virology ; Interferon-gamma ; secretion ; Interleukin-12 ; secretion ; Liver ; virology ; Lymphocytes ; secretion ; Mice ; Quercetin ; analogs & derivatives ; pharmacology ; Spleen ; pathology ; virology

<b>OBJECTIVEb>To study the inhibitory effect of binding peptides on duck hepatitis B virus (DHBV) replication in duck hepatocytes.

<b>METHODSb>Specific binding peptides to duck hepatitis B virus polymerase (DHBVP) were screened by phage display technology (PDT), then were sequenced and synthesized. Binding peptides were added into primary culture of duck hepatocytes infected with DHBV in vitro. DHBV-DNA in the cytoplasm, cell nucleus and medium supernatant was assayed over time.

<b>RESULTSb>Seven binding peptides were obtained after 3-round screening by PDT. Duck primary hepatocytes infected by DHBV were treated with above obtained binding peptides. The DHBV-DNA levels in medium supernatant and cytoplasm of duck hepatocytes treated with synthesized peptides (the 3rd and the 6th peptide) were significantly lower than those of control cells (P<0.05).

<b>CONCLUSIONb>Specific binding peptides to DHBVP could inhibit the replication of DHBV.

Animals ; Cells, Cultured ; Ducks ; Hepadnaviridae Infections ; virology ; Hepatitis B Virus, Duck ; drug effects ; genetics ; Hepatitis, Viral, Animal ; virology ; Hepatocytes ; virology ; Peptide Nucleic Acids ; pharmacology ; RNA-Directed DNA Polymerase ; metabolism ; Virus Replication ; drug effects

Animals ; Antiviral Agents ; pharmacology ; therapeutic use ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Ducks ; Glycyrrhizic Acid ; pharmacology ; therapeutic use ; Hepadnaviridae Infections ; drug therapy ; Hepatitis B Virus, Duck ; drug effects ; Hepatitis, Viral, Animal ; drug therapy ; Phytotherapy

<b>OBJECTIVEb>To study the viral inhibitory effect of Shenling Yigan Granule (SYG) on duck hepatitis B virus (DHBV) in vivo.

<b>METHODSb>Chongqing ducks infected with DHBV were used. They were randomly divided into five groups, the small-, medium- and high-dose (1.6 g/kg, 3.2 g/kg, 6.4 g g/kg) SYG groups, the lamivudine positive control group, and the model group. The changes of serum DHBV-DNA, DHB-sAg contents and hepatic pathology were observed.

<b>RESULTSb>The serum content of DHBV-DNA in the three SYG groups and the positive control group was significantly decreased (P < 0.05), while it was rebounded in the latter at day 7 after stopped lamivudine administration. The change of DHBsAg level was insignificantly in all groups. And the hepatic pathological change in the SYG groups and positive control group was slighter than that in the model control group, but showed insignificant difference in comparison between the SYG groups and the model group (P > 0.05).

<b>CONCLUSIONb>SYG has certain in vivo inhibitory effects on DHBV-DNA.

Animals ; Antiviral Agents ; pharmacology ; therapeutic use ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Ducks ; Hepadnaviridae Infections ; drug therapy ; Hepatitis B Virus, Duck ; drug effects ; Hepatitis, Viral, Animal ; drug therapy ; Phytotherapy ; Random Allocation

Brown ducks carrying DHBV were widely used as hepatitis B animal model in the research of the activity and toxicity of anti-HBV dugs. Studies showed that the ratio of DHBV carriers in the brown ducks in Guilin region was relatively high. Nevertheless, the characters of the DHBV genome of Guilin brown duck remain unknown. Here we report the cloning of the genome of Guilin brown duck DHBV and the sequence analysis of the genome. The full length of the DHBV genome of Guilin brown duck was 3 027bp. Analysis using ORF finder found that there was an ORF for an unknown peptide other than S-ORF, PORF and C-ORF in the genome of the DHBV. Vector NTI 8. 0 analysis revealed that the unknown peptide contained a motif which binded to HLA * 0201. Aligning with the DHBV sequences from different countries and regions indicated that there were no obvious differences of regional distribution among the sequences. A fluorescence quantitative PCR for detecting DHBV was establishment based on the recombinant plasmid pGEM-DHBV-S constructed. This study laid the groundwork for using Guilin brown duck as a hepatitis B animal model.
Animals ; Base Sequence ; China ; epidemiology ; Cloning, Molecular ; Ducks ; Genome, Viral ; Hepadnaviridae Infections ; diagnosis ; veterinary ; virology ; Hepatitis B Virus, Duck ; classification ; genetics ; isolation & purification ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction ; methods ; Poultry Diseases ; diagnosis ; virology

Rolling circle amplification (RCA) is a newly developed experimental technique that can specific ally amplify circular DNA. Since 2008, RCA has been extensively used in hepatitis B virus (HBV) research, such as the amplification of the full-length sequence of the HBV genome, and the analysis of the drug-resistant mutations of HBV covalently closed circular DNA (cccDNA), amongst others. To create an easy assay for the analysis of duck hepatitis B virus (DHBV) cccDNA, this study established an RCA-based method. DHBV cccDNA was amplified from the DHBV DNA samples of duck liver with four pairs of sulfur-modified primers, which were designed according to the highly conserved sequence of DHBV using sera DHBV DNA as the negative control. DHBV cccDNA was detected in the obtained RCA products by the sequencing of RCA amplicons that were amplified with primer pairs on both sides of the gap of DH BV relaxed circular DNA, rather than by digesting RCA products with a restriction enzyme. The liver and sera DHBV DNA samples of 39 ducks infected with DHBV were examined with the RCA-based DHBV cccDNA detection method, and the results showed that while DHBV cccDNA was detected from all 39 liver DHBV DNA samples, no DHBV cccDNA was found in any of the sera DHBV DNA samples. These results suggest that the method established in the study is highly specific and sensitive for the detection of DHBV cccDNA. The establishment of this RCA-based DHBV method for cccDNA detection lays the groundwork for using a DHBV model to study the role of cccDNA in the pathogenesis of hepatitis B and to evaluate the effect of anti-virus therapies.
Animals ; DNA Primers ; genetics ; DNA, Circular ; genetics ; DNA, Viral ; genetics ; Ducks ; Hepadnaviridae Infections ; veterinary ; virology ; Hepatitis B Virus, Duck ; genetics ; isolation & purification ; Liver ; virology ; Polymerase Chain Reaction ; methods ; Poultry Diseases ; virology

<b>OBJECTIVEb>To explore the inhibitory effect of combination of lamivudine with thymosin alpha1 (Talpha1) on the replication of duck hepatitis B virus (DHBV).

<b>METHODSb>Peking ducks of 1 d old were challenged with DHBV-positive serum and used as a duck hepatitis B model. After treated with lamivudine for three months, the ducks were randomly grouped and treated with or without Talpha1 for 8 d. Serum DHBV titrate was observed by semi-quantitative PCR, and inflammation and degeneration of hepatocytes were observed by pathology examination.

<b>RESULTSb>The serum DHBV titrate was significantly reduced (4483.2+/-5193.4 compared with 9351.8+/-5059.6) after lamivudine treatment, and it was reduced more significantly(1692.2+/-589.2) after combination treatment with Talpha1. Lamivudine reduced the degeneration degree of hepatocytes (3.2+/-0.8 compared with 4.6+/-0.5) and the inflammation degree of liver (6.2+/-3.3 compared with 8.6+/-2.8). The combination treatment with Talpha1 increased liver inflammation degree (9.0+/-5.2).

<b>CONCLUSIONb>Both Talpha1 and lamivudine may reduce the replication of DHBV in Peking ducks and combination treatment may have the better anti-virus effect and enhance immune response in liver.

Animals ; Animals, Newborn ; Antiviral Agents ; therapeutic use ; Cells, Cultured ; Drug Therapy, Combination ; Ducks ; Hepadnaviridae Infections ; drug therapy ; Hepatitis B Virus, Duck ; drug effects ; genetics ; Hepatitis, Viral, Animal ; drug therapy ; Hepatocytes ; virology ; Lamivudine ; therapeutic use ; Thymosin ; analogs & derivatives ; therapeutic use ; Virus Replication ; drug effects

<b>OBJECTIVEb>To develop a standard duck hepatitis B virus (DHBV) animal model using a local Hubei species of duck, Ma Ya, and use it as an in vivo experimental system to study antiviral strategies against hepatitis B.

<b>METHODSb>Two-day-old Ma Ya ducklings were experimentally infected via intraperitoneal injection with the DHBV inocula which was collected from the transfected culture supernatant of 1.5-fold-overlength genome recombinant plasmid. Blood samples were taken twice or thrice a week during post-inoculation for 50 days. Viremia was quantified by serum real-time PCR to show the peak. Antiviral treatment of the DHBV-infected ducklings was started 3 d post-inoculation. The animals received oral administration of lamivudine (3TC) at a dose of 25 mg/kg/d for 5 d, followed by a maintenance therapy thrice weekly for 3 more weeks. Serum was quantified to show the viremia peak and liver biopsy specimens were analysed by Southern blotting and in-situ hybridization at the end of antiviral drug treatment.

<b>RESULTSb>The experimental infection rate of 2-day-old ducklings was 87.5%. Viremia started to be detectable on day 7 and reached a peak on day 11 post-inoculation, followed by a decrease and fluctuations. Four weeks of oral administration of 3TC led to a significant decrease in viremia peak during. This effect was not sustained, as a rebound in viremia was observed after drug withdrawal. Similarly, the analysis of liver biopsies at the end of 3TC treatment showed a marked decrease in DHBV DNA. However, after drug withdrawal a rebound of intrahepatic DHBV DNA was observed in duck livers.

<b>CONCLUSIONb>The Hubei duck model with experimental DHBV infection of transfected supernatant is more suitable for the hepadnavirus biologic research due to its stability and practicability.

Animals ; Animals, Newborn ; DNA, Viral ; genetics ; metabolism ; Disease Models, Animal ; Ducks ; Hepadnaviridae Infections ; blood ; drug therapy ; virology ; Hepatitis B Virus, Duck ; drug effects ; genetics ; growth & development ; Hepatitis, Viral, Animal ; blood ; drug therapy ; virology ; Lamivudine ; pharmacology ; Liver ; drug effects ; pathology ; virology ; Reverse Transcriptase Inhibitors ; pharmacology ; Viremia ; blood