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

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

It has been previously shown that Taraphochlamys affinis possessed anti-hepatitis B virus (HBV) activities. To identify the active ingredients, the total saponins (TSTA) were isolated from T. affinis and the inhibitory effect of TSTA on HBV in the duck HBV model was examined. The results showed that serum levels of DHBV-DNA decreased in all ducks treated with TSTA (1.0 and 2.0 g x kg(-1) x d(-1)) and lamivudine (3TC) (50 mg x kg(-1) x d(-1)) during treatment, but 7 days after the cessation of treatment (p7) with 3TC, the viral replication level returned to the pretreatment baseline. Contrariwise in ducks treated with TSTA, the effect of DHBV DNA inhibition lasted. Compared with model control group,the alanine aminotransferase (ALT), aspartate aminotransferase (AST) and duck hepatitis B surface antigen (DHBsAg) values of 1.0 and 2.0 g x kg(-1) x d(-1)-dose TSTA groups were significantly lower on 7, 14 days after the treatment (d7, d14) and p7, and at p7, the ALT and DHBsAg levels of 2.0 g x kg(-1) x d(-1)-dose TSTA group was significantly lower than that of 3TC group. Furthermore, significant histological improvement was noted in ducklings of TSTA treatment group 7 days after the withdrawal. The study results demonstrate that TSTA possesses potent anti-HBV activity.
Animals ; Antigens, Surface ; blood ; Antiviral Agents ; administration & dosage ; isolation & purification ; pharmacology ; DNA, Viral ; blood ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Hepadnaviridae Infections ; drug therapy ; virology ; Hepatitis B Virus, Duck ; drug effects ; immunology ; Hepatitis, Viral, Animal ; drug therapy ; virology ; Liver ; drug effects ; metabolism ; pathology ; Liver Function Tests ; Saponins ; administration & dosage ; isolation & purification ; pharmacology ; Virus Replication ; drug effects

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>OBJECTIVEb>To construct a lamivudine-resistant plasmid containing 1.2 unit genome of duck hepatitis B virus and identify its replication and drug-resistance in avian LMH hepatica cells.

<b>METHODSb>The recombinant plasmid PBS-DHBV1.2 was constructed using the 1.2-genome length DHBV DNA sequence from a dimer DHBV genome with pcDNA3.1 as the template. With site-directed mutagenesis, we obtained PBS-DHBV1.2-M512V plasmids with polymerase gene mutation from PBS-DHBV1.2. Two constructed plasmids were transiently transfected into LMH cells using FuGENETM6 transfection reagent and cultured in the medium containing different concentrations of lamivudine. Southern blot hybridization was performed to detect DHBV replication intermediates.

<b>RESULTSb>PCR amplification, restriction digestion and plasmid sequencing all confirmed successful construction of PBS-DHBV1.2-M512V recombinant plasmid. Southern blot analysis identified the presence of all the expected DHBV replication intermediates in LMH cells. The replication capacity of the mutant plasmid was decreased by 2.7 times compared with that of the wild plasmid. The IC(50) of lamivudine was 37.12∓8.81 ng/ml for the mutant, greater than that of the wild plasmid (10.90∓4.80 ng/ml).

<b>CONCLUSIONb>Compared with the wild plasmid, the mutant plasmid has a lower replication capacity and sensitivity to lamivudine in vitro.

Antiviral Agents ; pharmacology ; Drug Resistance, Viral ; drug effects ; genetics ; Hepatitis B Virus, Duck ; drug effects ; genetics ; Lamivudine ; pharmacology ; Mutagenesis, Site-Directed ; Plasmids

Previously, we have established an epsilon library and selected out a series of RNA aptamers with higher affinity to P protein based on the in vitro Systematic Evolution of Ligands by Exponential Enrichment (SELEX) in duck hepatitis B virus (DHBV) system. In order to study the structural elements within the epsilon that is essential for initiating priming of HBV reverse transcriptase (P protein), all selected aptamers were subjected to in vitro priming assay and RNA secondary structure probing. We found that all those aptamers supporting priming had an undamaged bulge, while those lacking of the bulge no more support priming. Our results suggest an undamaged bulge within Depsilon is indispensable for initiating priming of P protein.
Base Sequence ; Hepatitis B Virus, Duck ; chemistry ; enzymology ; genetics ; Molecular Sequence Data ; Nucleic Acid Conformation ; RNA, Viral ; chemistry ; genetics ; RNA-Directed DNA Polymerase ; genetics ; metabolism ; Reverse Transcription ; Sequence Alignment ; Viral Proteins ; genetics ; metabolism

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

Animals ; Antiviral Agents ; pharmacology ; Cell Cycle ; Cell Proliferation ; DNA, Circular ; physiology ; DNA, Viral ; physiology ; Ducks ; Half-Life ; Hepatitis B Surface Antigens ; metabolism ; Hepatitis B Virus, Duck ; genetics ; physiology ; Hepatitis B virus ; genetics ; physiology ; Hepatitis, Viral, Animal ; virology ; Hepatitis, Viral, Human ; virology ; Humans ; Liver ; pathology ; virology ; Virus Replication

<b>OBJECTIVEb>We have evaluated the direct effect of ampelopsis (APS) on duck hepatitis B virus (DHBV) replication in ducklings in vivo.

<b>METHODb>One-day-old ducklings were infected with DHBV. After infection for 7 days, the animals were treated with APS at dosages of 70, 150, 300 mg x kg(-1) of body weight via the oral route. The drug was given twice per day for 10 days continuously, and normal saline was used as control. The blood was drawn from the posterior tibial vein of all ducks before treatment (T0), after the medication for 5 (T5), 10 (T10) days and withdrawal of the drug for 3 days (P3). DHBV DNA in duck serum was detected by dot blot.

<b>RESULTb>The duck serum DHBV-DNA levels were reduced in the group of APS (150, 300 mg x kg(-1)) after treated for 5 and 10 days and the levels of DHBV-DNA did not markedly relapse in both groups of APS after withdrawal of the drug for 3 days. We provide the first evidence that APS can efficiently inhibits DHBV replication in ducks in vivo.

<b>CONCLUSIONb>APS therefore warrants further investigation as a potential therapeutic agent for HBV infections.

Ampelopsis ; chemistry ; Animals ; Antiviral Agents ; pharmacology ; DNA, Viral ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Ducks ; blood ; virology ; Hepatitis B Virus, Duck ; drug effects ; metabolism ; physiology ; 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