Neuronal PC12 cells induced by nerve growth factor (NGF) have been considered to be postmitotic and lack the ability to divide. However, in this study, we not only detected DNA synthesis but also observed cell division in some morphologically differentiated neuronal PC12 cells bearing long neurites. More interestingly, in addition to the division of perikaryon, the neurites located on the division site of the cell membrane also divided into two parts and were allocated to the two daughter cells. These results demonstrate that the morphologically differentiated neuronal PC12 cells still retain the ability to divide. This is the first report that neuronal PC12 cells as well as their neurites can divide.
Animals ; Cell Differentiation ; drug effects ; Cell Division ; drug effects ; DNA Replication ; drug effects ; physiology ; Nerve Growth Factor ; pharmacology ; Neurites ; drug effects ; Neurons ; cytology ; PC12 Cells ; Rats

This study is to establish a cell-based pharmacological model targeting HIV-1 replication for compounds screening and to screen compounds randomly selected from compounds library by using this pseudotyped viral system. The cell-based HIV-1 replication pharmacological model was set up by HIV-1 core packed with vesicular stomatitis virus glycoprotein. The level of HIV-1 replication was presented by reporter genes expression (luciferase activity or percentage of GFP positive cells). When a compound has inhibitory effect on VSVG/HIV model, VSVG/MLV model would be used to test for specificity. Vesicular stomatitis virus glycoprotein can efficiently mediate HIV core into a wide range of host cells. Expression level of reporter genes showed dose-dependent manner with virion dilution. Among 500 compounds, three compounds dose-dependently inhibit HIV-1 replication, but not MLV replication. VSVG/HIV pseudotyped viral system can be used as a pharmacological model for HIV-1 replication inhibitor screening. Compounds 2-methylthio-5-(4-methylbenzo)amido-l,3,4-thiadiazole, N-(3-hydroxyphenyl)-2-(4-isobutylphenyl) propionamide, and N-(4-picolyl)-4-methylbenzenesulfonamide can specifically inhibit HIV-1 replication with IC50 of 1.92, 5.38, and 3.39 micromol L(-1) respectively.
Anti-HIV Agents ; pharmacology ; DNA Replication ; drug effects ; Didanosine ; pharmacology ; Drug Evaluation, Preclinical ; methods ; Genes, Reporter ; drug effects ; genetics ; HIV-1 ; drug effects ; physiology ; Humans ; Lamivudine ; pharmacology ; Pseudocowpox Virus ; Tumor Cells, Cultured ; Virus Replication ; drug effects ; Zidovudine ; pharmacology

BACKGROUNDTo determine the feasibility of inhibition of duck hepatitis B virus (DHBV) DNA replication by antisense phosphorothioate oligodeoxynucleotides corresponding to DHBV transcription region.

METHODSThe 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.

RESULTSPrimary 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.

CONCLUSIONSThe 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

Betulinic acid is a naturally occurring pentacyclic triterpenoid, which has antiretroviral, antimalarial, and anti-inflammatory properties. The purpose of this study is to investigate the HBV DNA replication inhibition in the mouse model with betulinic acid. Hydrodynamic injection method via the tail vein with the Paywl. 3 plasmid was used to establish the animal mode (n = 15), and the mice were randomly divided into the PBS control group (n = 5), Betulinic acid treatment group (n = 5) and lamivudine control group (n = 5). The day after successful modeling , the mice would have taken Betulinic acid (100 mg x kg(-1)), lamivudine (50 mg x kg(-1)), PBS drugs orally, once daily for 7 days, blood samples were acquired from the orbital venous blood at 3, 5, 7 days after the administering, HBsAg and HBeAg in serum concentration were measured by ELISA and the mice were sacrificed after 7 days, HBV DNA southern detections were used with part of mice livers. The results showed that betulinic acid significantly inhibited the expression of HbsAg in the mice model at the fifth day compared with the control group, and there was no significant differences between the effects of lamivudine and the PBS control group; both the betulinic acid and lamivudine groups had no significant inhibition for the HBeAg expression; the HBV DNA expressions of the liver tissue from the betulinic acid and lamivudine groups were inhibited compared with the control group. Taken together, these results reveal betulinic acid can inhibit the HBsAg expression and replication of the liver HBV DNA in the mouse model.
Acute Disease ; Animals ; Antiviral Agents ; pharmacology ; DNA Replication ; drug effects ; DNA, Viral ; biosynthesis ; Hepatitis B ; blood ; virology ; Hepatitis B Surface Antigens ; blood ; Hepatitis B virus ; drug effects ; genetics ; immunology ; physiology ; Male ; Mice ; Plasmids ; genetics ; Triterpenes ; pharmacology ; Virus Replication ; drug effects

This study examined the effect of artesunate (Art) on the proliferation, DNA replication, cell cycles and apoptosis of vascular smooth muscle cells (VSMCs). Primary cultures of VSMCs were established from aortas of mice and artesunate of different concentrations was added into the medium. The number of VSMCs was counted and the curve of cell growth was recorded. The activity of VSMCs was assessed by using MTT method and inhibitory rate was calculated. DNA replication was evaluated by [3H]-TdR method and apoptosis by DNA laddering and HE staining. Flowmetry was used for simultaneous analysis of cell apoptosis and cell cycles. Compared with the control group, VSMCs proliferation in Art interfering groups were inhibited and [3H]-TdR incorprating rate were decreased as well as cell apoptosis was induced. The progress of cell cycle was blocked in G0/G1 by Art in a dose-dependent manner. It is concluded that Art inhibits VSMCs proliferation by disturbing DNA replication, inducing cell apoptosis and blocking cell cycle in G0/G1 phase.
Aorta/cytology ; Apoptosis/*drug effects ; Artemisinins/*pharmacology ; Cell Cycle/drug effects ; Cells, Cultured ; DNA Replication/*drug effects ; Muscle, Smooth, Vascular/*cytology ; Sesquiterpenes/*pharmacology

OBJECTIVETo explore the inhibitory effect of norcantharidin (NCTD) on the expression of DNA replication initiation protein Cdc6 in cancer cells.

METHODSMTT assay was performed to detect the inhibitory effect on different cancer cell lines, including HeLa, HepG2, Jurkat and Ramos cells. The effect of NCTD on Cdc6 protein level was detected by Western blotting, and BrdU incorporation assay was used to evaluate the DNA replication of the cells.

RESULTSNCTD significantly inhibited the proliferation of the cells and caused degradation of Cdc6 protein to result in the inhibition of the DNA replication of the cells shown by BrdU incorporation assay.

CONCLUSIONNCTD can induce the degradation of Cdc6 in cancer cells to produce an anti-cancer effect.

Bridged Bicyclo Compounds, Heterocyclic ; pharmacology ; Cell Cycle Proteins ; metabolism ; Cell Line, Tumor ; DNA Replication ; drug effects ; Humans ; Nuclear Proteins ; metabolism

The fluoroquinolones are the most widely used broad-spectrum antibiotics, accounting for 18% of global antibacterial market share. They can kill bacteria rapidly with variety of derivatives available. Different quinolones vary significantly in rate and spectrum of killing, oxygen requirement for metabolism and reliance upon protein synthesis. Further understanding the sophisticated mechanisms of action of this important antibiotic family based on the molecular genetic response of bacteria can facilitate the discovery of better quinolone derivatives. Factors such as SOS response, bacterial toxin-antitoxin system, programmed death, chromosome fragmentation and reactive oxygen have been implicated in the action to some extent. "Two steps characteristic" of quinolones killing is also emphasized, which might inspire future better quinolones modification.
Anti-Bacterial Agents ; pharmacology ; Apoptosis ; drug effects ; Bacteria ; drug effects ; enzymology ; genetics ; Chromosomes, Bacterial ; drug effects ; DNA Cleavage ; drug effects ; DNA Gyrase ; drug effects ; DNA Replication ; drug effects ; DNA Topoisomerases ; drug effects ; Fluoroquinolones ; pharmacology ; Quinolones ; pharmacology ; Reactive Oxygen Species ; SOS Response (Genetics) ; drug effects

OBJECTIVEWe have evaluated the direct effect of ampelopsis (APS) on duck hepatitis B virus (DHBV) replication in ducklings in vivo.

METHODOne-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.

RESULTThe 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.

CONCLUSIONAPS 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

AIMNucleoside analogues have become the most promising candidates of anti-HBV drugs. In this study, beta-L-D4A was synthesized and explored its inhibitiory action against hepatitis B virus (HBV) in 2. 2. 15 cells derived from HepG2 cells transfected with HBV genome.

METHODSbeta-L-D4A was stereo-controlled synthesized from D-glutamic acid, and the structure was identified by IR, 1H NMR and MS. 2. 2. 15 Cells were placed at a density of 5 x 10(4) per well in 12-well tissue culture plates, and treated with various concentrations of beta-L-D4A for 6 days. At the end, medium was processed to obtain virions by a polyethlene glycol precipitation method. At the same time, intracellular DNA was also extracted and digested with Hind III. Both of the above DNA were subjected to Southern blot, hybridized with a 32P-labeled HBV probe and autoradiographed. The intensity of the autoradiographic bands was quantitated by densitometric scans of computer and EC50 was calculated. 2. 2. 15 cells were also seeded in 24-well tissue culture plates, and cytotoxicity with different concentrations was examined by MTT method. IC50 was calculated.

RESULTSThe synthesized compound structure conformed with beta-L-D4A; Autoradiographic bands showed similar for supernatant and intracellular HBV DNA. Episomal HBV DNA was inhibited in a dose-dependent manner. EC50 0.2 micromol x L(-1). The experiment of cytotoxicity gained IC50 200 micromol x L(-10.

CONCLUSIONbeta-L-D4A has been synthesized successfully. beta-L-D4A possessed potent inhibitory effect on replication of HBV in vitro with low cytotoxicity, TI value was 1 000. It is expected to be developed clinically into a new anti-HBV drug.

Antiviral Agents ; chemical synthesis ; chemistry ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA Replication ; drug effects ; DNA, Viral ; drug effects ; Dideoxyadenosine ; analogs & derivatives ; chemical synthesis ; chemistry ; pharmacology ; Genome, Viral ; Hepatitis B virus ; drug effects ; genetics ; physiology ; Humans ; Liver Neoplasms ; pathology ; Transfection ; Virus Replication ; drug effects

OBJECTIVETo investigate the relationships between skin photoaging and point mutations in mitochondrial DNA (mtDNA) control region for replication of dermal fibroblast.

METHODSCultured dermal fibroblasts were treated by 8-methoxypsora len /ultraviolet A (8-MOP/UVA). mtDNA was extracted by one-step-method and th e PCR products of D-loop and adjacent transcription promoter (DLP(6)) fragment of mtDNA control region for replication were detected by polymerase chain reaction-single strain conformation polymorphism and direct sequencing.

RESULTSAfter treated by 8-MOP/UVA, point mutations of 414 T-->G of DLP(6) fragment of mtDNA control region for replication largely accumulated.

CONCLUSIONAccumulation of point mutations of DLP(6) fragment of mtDNA control region for replication may be closely associated with skin photoaging.

Adult ; Binding Sites ; Cells, Cultured ; DNA Replication ; DNA, Mitochondrial ; drug effects ; radiation effects ; Dermis ; cytology ; Fibroblasts ; cytology ; drug effects ; radiation effects ; Humans ; Male ; Methoxsalen ; pharmacology ; Photosensitizing Agents ; pharmacology ; Point Mutation ; Ultraviolet Rays