<b>OBJECTIVEb>To investigate the effect of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) mediated antiviral activity against hepatitis B virus (HBV) and duck hepatitis B virus (DHBV).

<b>METHODSb>Total RNA was extracted from peripheral blood mononuclear cells (PBMCs), RT-PCR product was cloned into the EcoR I/Hind III restriction sites of the CMV-driven expression vector fused with a hemagglutinin fusion epitope tag at its carboxyl terminal. Replication competent 1.3 fold over-length HBV was constructed with full-length HBV of ayw subtype. The mammalian hepatoma cell HepG2 was cotransfected with the replication competent 1.3 fold over-length HBV and various amounts of CMV-driven expression vector encoding APOBEC3G-HA. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA, HBV DNA. RNA from intracellular core particles was examined using Northern and Southern blot analyses. Chicken hepatoma cell LMH was cotransfected with head-to-tail dimer of an EcoR I monomer of DHBV and various amounts of CMV-driven expression vector encoding APOBEC3G-HA. DHBV DNA from intracellular core particles was examined using Southern blot analysis.

<b>RESULTSb>CMV-driven expression vector encoding APOBEC3G-HA and replication competent 1.3 fold over-length HBV were constructed. There was a dose dependent decrease in the levels of intracellular core-associated viral (HBV and DHBV) DNA and extracellular production of HBsAg and HBeAg. Levels of intracellular core-associated viral RNA were also decreased, but the expression of HBcAg remained almost unchanged.

<b>CONCLUSIONb>APOBEC3G suppresses HBV and DHBV replication and also suppresses HBsAg and HBeAg expression.

APOBEC-3G Deaminase ; Cytidine Deaminase ; genetics ; Hep G2 Cells ; Hepatitis B Surface Antigens ; metabolism ; Hepatitis B Virus, Duck ; physiology ; Hepatitis B e Antigens ; metabolism ; Hepatitis B virus ; physiology ; Humans ; RNA, Messenger ; genetics ; Virus Replication

<b>OBJECTIVEb>To clone and analyze duck hepatitis B virus genome from Chongqing brown duck.

<b>METHODSb>Duck hepatitis B virus (DHBV) DNA extracted from a Chongqing brown duck was amplified by PCR and cloned into PGEM-T vector using T-A clone method. The sequence of this DHBV genome was analyzed with some softwares after identified.

<b>RESULTSb>The duck hepatitis B virus genome from Chongqing brown duck (DHBVcq), which was 3 024 nucleotides long, contained three ORFs whose onset and end nucleotides were in accord with those of HPUGA, encoding P, PreC/C and PreS/S protein respectively. Comparison of this strain with other DHBV reported in GenBank showed that the homology of DHBVcq and M32990 got the highest score of 94.9% at nucleotide level, while DHBVcq and DHBVCG got the least (89.8%). Most of the conserved regulation nucleotides and amino acids sequence found in other DHBV were also identified in DHBVcq. The epsilon region of DHBVcq, which was important for encapsidation of pgRNA and synthesis of minus-strand DNA, differed from that of most other DHBV strains, forming a stem-loop conformation with a three- nucleotides upper stem rather than a common nine-nucleotides one in free status.

<b>CONCLUSIONb>The successful clone and analysis of DHBVcq provide further studies with helpful information.

Animals ; Cloning, Molecular ; DNA, Viral ; chemistry ; genetics ; Ducks ; Hepatitis B Virus, Duck ; classification ; genetics ; Hepatitis Virus, Duck ; genetics ; Open Reading Frames ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; Sequence Homology

<b>OBJECTIVEb>To discuss the possibility of hepatitis B virus (HBV) transmission through dental handpieces.

<b>METHODSb>Investigation was carried on methods for disinfecting and sterilizing dental handpieces and the condition of HBsAg contamination on dental handpieces before and after disinfection and sterilization by randomly sampling all special stomatological hospitals and dental clinics in a same city and 10 dental departments from the third, second and first class hospitals. The possibility of HBV transmission through dental handpieces was probed by investigating whether ducks can be infected by bath liquid of dental handpieces contaminated by DHBV, while in such bath liquid, DHBV can not be detected by serum dot hybridization.

<b>RESULTSb>From 2001 to 2004, in methods to disposing dental handpieces, the use of autoclave was remarkably increased while of the disinfectant wipe, immersion and other methods was remarkably decreased. The positive rate of HBsAg from dental handpieces in practice was 1.65%. It was evident that the bath liquid of dental handpieces contaminated by DHBV can conduct infection in vivo test of duck, while DHBV can not be detected in such bath liquid by serum dot hybridization, it is proved that the negative result of HBsAg in non-sterilized dental handpieces can not eliminate the possibility of HBV transmission through dental handpieces.

<b>CONCLUSIONb>There might exist the possibility of HBV transmission through dental handpieces however, the autoclaves might kill the virus contaminating on dental handpieces.

Animals ; DNA, Viral ; blood ; Dental Instruments ; virology ; Ducks ; virology ; Equipment Contamination ; Hepatitis B ; transmission ; Hepatitis B Virus, Duck ; genetics ; isolation & purification ; Sterilization ; methods ; standards

<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

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

Animals ; DNA, Viral ; genetics ; isolation & purification ; Ducks ; Hepatitis B Virus, Duck ; genetics ; isolation & purification ; Hepatitis, Viral, Animal ; virology ; Organic Chemicals ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity

<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

<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

<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 ; 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