Hepatitis B ; virology ; Hepatitis B virus ; physiology ; Humans ; Virus Replication

HIV Infections ; virology ; HIV-1 ; physiology ; Virus Replication ; physiology

Herpes simplex virus (HSV), including HSV-1 and HSV-2, is an important pathogen that can cause many diseases. Usually these diseases are recurrent and incurable. After lytic infection on the surface of peripheral mucosa, HSV can enter sensory neurons and establish latent infection during which viral replication ceases. Moreover, latent virus can re-enter the replication cycle by reactivation and return to peripheral tissues to start recurrent infection. This ability to escape host immune surveillance during latent infection and to spread during reactivation is a viral survival strategy and the fundamental reason why no drug can completely eradicate the virus at present. Although there are many studies on latency and reactivation of HSV, and much progress has been made, many specific mechanisms of the process remain obscure or even controversial due to the complexity of this process and the limitations of research models. This paper reviews the major results of research on HSV latency and reactivation, and discusses future research directions in this field.
Herpes Simplex ; virology ; Herpesvirus 1, Human ; physiology ; Humans ; Virus Activation ; physiology ; Virus Latency ; physiology ; Virus Replication

DNA Replication ; Epigenesis, Genetic ; Hepatitis B virus ; genetics ; physiology ; Virus Replication

Real-time quantitative PCR was used to characterize HearNPV DNA replication in exponential and stationary phases of HzAM1 cells. Results showed that the doubling time of HzAM1 cells was 22 h in exponential phases. Most of the exponential cells were in S phase (48.6%), and most of the stationary cells in G2/M phase (72.6%). The replication of viral DNA was completed within 60 h post infection (h p. i.) in different phases of HzAM1 cells. During 14 to 20 h p. i., the doubling time of HearNPV replica-tion was 1.8 h in exponential cells and 1.9 h in stationary cells, and no significant difference was found between them. But the amounts of BV entering and releasing, the final progeny virions and viral protein products in the infected exponential phase cells were obviously higher than that in the stationary phase cells. 25% of the total synthesized viral DNAs were released from infected exponential phase cells, but on-ly 13% from the infected stationary phase cells. Viral DNA started to be replicated from 7-8 h p. i. both in infected exponential phase and in stationary phase cells. But in infected exponential phase cells, BVs were started to release from 18-20 h p. i., and BVs were started to release from 22-25 h p. i. from infected sta-tionary phase cells. During 30-60 h p. i., the BV releasing rate was about 483 copies/cell/h in the expo-nential phase cells, but was 100 copies/cell/h in the stationary-phase cells. The initial viral DNA entering into exponential phase cells was much more than that entered into the stationary phase cells. The data of cell membrane fluidity at exponential and stationary phases suggested that the fluidity of cell membrane played an important role during virus entry.
Animals ; Cell Cycle ; Cell Line ; DNA Replication ; Membrane Fluidity ; Moths ; Nucleopolyhedrovirus ; physiology ; Virus Internalization ; Virus Replication

Norovirus ; chemistry ; genetics ; physiology ; ultrastructure ; Open Reading Frames ; Virus Replication

OBJECTIVETo investigate the change of viral titers under different conditions in cultured cells persistently-infected with different strains of Japanese encephalitis virus (JEV) and find out the factors that influence viral multiplication.

METHODSJEV JaGAr-01 and Nakayama wild strains were used to infect human hepatoma cell line KN73 respectively, and the persistent infection model was established. Viral titers were examined by plaque methods using BHK cells. Human nerve fibroblastoma cell line IMR-32 was infected with the strains of the virus that can cause persistent infection, and the thermal sensitivity of the viral strains was measured at 30 degrees C and 37 degrees C. KN73 cells persistently infected with JEV were infected with two JEV strains respectively, and viral superinfection was studied. To explore the replication of the persistently-infected viruses, KN73 and IMR-32 cells were infected with the viral strains.

RESULTSTwo persistently infected viral strains did not show any thermal difference. The results of superinfection were that the viral titers of JaGAr-01 strains were 1.3 and 8.8 percent of the control, respectively, and the viral titers of Nakayama strain were 80 and 1.7 percent of the control, respectively. JaGAr-01 wild strains, Nakayama wild strains and their persistently-infected strains infected KN73 and IMR-32 respectively. The replication of the persistently-infected strains was obviously lower than the wild strains in KN73 cells, however, in IMR-32 cells their replication was similar.

CONCLUSIONSThe two strains of JEV were not found to be temperature-mutant. It is possible that mutant viruses containing DI particles exist in JEV persistently-infected strains. In different cells there may be different host factors hindering the replication of the persistently-infected strains.

Animals ; Cell Line ; Encephalitis Virus, Japanese ; genetics ; physiology ; Encephalitis, Japanese ; virology ; Humans ; Virus Cultivation ; Virus Replication

Viral infection of cells is a highly intricate process that involves the complex virus-cell interactions. Recently, virologists can monitor the virus life cycle at the primary infection site in real-time using various virus tracking techniques. Herpesviruses, a class of large enveloped DNA viruses, are important pathogens threatening the health of humans and animals. This review discussed the applications of different virus tracking techniques in herpesvirus studies, to provide new insights into virus-cell interactions and replication mechanisms of herpesviruses. Though the techniques have widely been exploited, some issues need to be addressed, such as the selection of the optimal site to insert reporters and the inability to track the whole process of the virus life cycle. With the updated tracking techniques, hopefully, more complex replication mechanismsof herpesviruses will be revealed in detail.
Animals ; Herpesviridae ; pathogenicity ; physiology ; Humans ; Virus Diseases ; Virus Physiological Phenomena ; Virus Replication

We investigated inhibition of Moloney leukemia virus 10 (MOV10) upon xenotropic murine leukemia virus-related virus (XMRV) and made a preliminary study of the mechanism of action. Using transfection, infection, western blotting and real-time polymerase chain reaction, we found that MOV10 inhibited XMRV replication. Using MOV10 overexpressed in viral producer cells, MOV10 was shown to reduce the infectivity of XMRV. MOV10 could be incorporated into XMRV, suggesting that MOV10 could undergo encapsidation by XMRV during viral assembly. MOV10 could also restrict the DNA production of XMRV in target cells. We found that the putative RNA-helicase domain of MOV10 maintained most of its XMRV inhibition. These results suggest that MOV10 could be required during the retroviral lifecycle. Perturbation of MOV10 disrupts the generation of infectious viral particles, suggesting that MOV10 has broad antiretroviral activity. Hence, MOV10 could be actively involved in host defense against retroviral infection.
Humans ; Moloney murine leukemia virus ; physiology ; RNA Helicases ; physiology ; Virus Replication

OBJECTIVETo investigate the effect of HS3ST3B1 on hepatitis B virus (HBV) replication.

METHODSHepG2 cells were classified into 7 groups according to the plasmids transfected: (1) Blank group, no plasmid transfected; 2. Positive control, transfected with pCH9-HBV which permits HBV replication; (3) Negative control, transfected with pCH9-HBV + pcDNA3.1 + pTZU6+1; (4) Treatment A, transfected with pCH9-HBV + pCDNA3.1-HS3ST3B1 + pTZU6+1; (5) Interference A, transfected with pCH9-HBV + pCDNA3.1-HS3ST3B1 + psh1126 (a plasmid to interfere HS3ST3B1 expression); (6) Treatment B, transfected with pCH9-HBV + pTZU6+1; (7) Interference B, transfected with pCH9-HBV + psh1126. The levels of HBV DNA were detected in the above groups by Southern blotting. HBV total RNA of Negative control, Treatment A and Interference A were quantified by Real-time PCR to determine the influence of HS3ST3B1 over-expression on the HBV RNA transcription. The activity of the four HBV promoters [core promoter (cp), x promoter(xp), surface antigen promoter1(sp1), surface antigen promoter2 (sp2)] were assayed by Dual-Luciferase Reporter Assay System. The data was analyzed using one way ANOVA, with P < 0.05 indicating statistically meaningful difference.

RESULTSouthern blot data revealed the level of HBV DNA in Treatment A and Interference A accounted for 10% +/- 2% and 31% +/- 4% of that in control. Compared with control, a statistical difference existed between Treatment A and Control, with F value equalling to 20.8 and P value equalling to 0.034 respectively. A statistical difference also existed between Interfere A and Treatment A, with F value equalling to 24.9 and P value equalling to 0.021 respectively. The level of HBV DNA in Experiment B was raised by 130% +/- 11% as compared to that in Interference B, and the levels of HBV DNA showed a dose-dependent decrease when H7 cells were transfected with 0.5, 1.0, 1.5 microg pCDNA3.1-HS3ST3B1 respectively. Statistical differences existed between control and H7 transfected with different dose of pCDNA3.1-HS3ST3B1, with F values equalling to 22.7, 20.3, 26.5 and P values equalling to 0.029, 0.041 and 0.015 respectively. Real-time PCR revealed that the HBV total RNA in Treatment A accounted for 17.0% +/- 2.7% of that in control and there was a statistical difference between Treatment A and control, with F value equalling to 25.6 and P value equalling to 0.018. In addition, HBV DNA in Interference A was restored to 74.0% +/- 3.9% of that in control, and there was also a statistical difference between Treatment A and Interference A, with F value equalling to 21.3 and P value equalling to 0.032. However, the down regulation of HBV total RNA had nothing to do with HBV promoters activity.

CONCLUSIONHS3ST3B1 can inhibit HBV replication and reduce the level of HBV total RNA, but the downregulation of HBV total RNA may not be the result of direct interaction of HS3ST3B1 and HBV promoters.

DNA Replication ; DNA, Viral ; biosynthesis ; Hep G2 Cells ; Hepatitis B virus ; genetics ; physiology ; Humans ; Plasmids ; Sulfotransferases ; genetics ; Transfection ; Virus Replication