With its abilities of trans-synaptic tracing and self-replication and wide host range, pseudorabies virus (PRV) has been applied in the field of neuroanatomy since the 1970s. Four decades of PRV application have made many advances in researches on neuronal tracing with PRV. Mechanism studies focused on investigating infection of primary neurons and tracing direction in secondary neurons, while application studies focused on development of new pathological strains and innovation of tracing techniques. To date, the mechanism and application of viral tracing are not completely figured out yet. Integration of molecular biology technology will improve the efficiency in related researches.
Animals ; Cell Tracking ; Herpesvirus 1, Suid ; genetics ; physiology ; Humans ; Neurons ; virology ; Pseudorabies ; virology

In addition to the structural genes of the coronavirus genome, S, E, M, and N, there are several additional genes called "group-specific or accessory genes". Their gene products are designated as "accessory proteins", as reports to date make it clear that these proteins are not essential for virus replication in vitro. Nevertheless, many of these genes are still maintained in the virus genome under selective pressure, suggesting that they might play a very important role in the survival of the virus in the natural environment of the infected host. This review will summarize the research progress in the functions of coronavirus accessory genes.
Animals ; Coronavirus ; genetics ; metabolism ; Coronavirus Infections ; virology ; Humans ; Open Reading Frames ; Viral Proteins ; metabolism

Oncolytic adenoviruses (Ads), which are live, replication-competent viruses that can selectively replicate in tumor cells and lead to cell lysis, have been used in tumor therapy. But due to the complexity and high mutability of human tumors, it becomes a major strategy to improve the selectivity, efficacy, and safety of oncolytic Ads. The oncolytic Ads that can express short hairpin RNA, cytokines, suicide gene, and matrix-modulating proteins have higher antitumor activity than the wild type. Tumor-specific promoters, especially hTERT and HRE promoters, increase the selectivity of oncolytic Ads for tumor cells. Moreover, oncolytic Ads surface-modified by polyethylene glycol (PEG), liposomes, biodegradable nanoparticles, and polypeptides have reduced immunogenicity and hepatotoxicity and improved antitumor activity when systemically administered, and the selectivity of oncolytic Ads can be significantly increased when linking PEG to antibodies, small peptides, cytokines, and ligands. Therefore, engineered oncolytic Ads combining the advantages of viral and non-viral vectors, as well as immunotherapy, are a promising strategy for improving the efficacy of targeted virotherapy.
Adenoviridae ; genetics ; physiology ; Animals ; Humans ; Neoplasms ; therapy ; virology ; Oncolytic Virotherapy ; trends ; Virus Replication

Wild birds (mainly Anseriformes and Charadriiformes) are recognized as the natural reservoir of avian influenza viruses (AIVs). The long-term surveillance of AIVs in wild birds has been conducted in North America and Europe since 1970s. More and more surveillance data revealed that all the HA and NA subtypes of AIVs were identified in the wild ducks, shorebirds, and gulls, and the AIVs circulating in wild birds were implicated in the outbreaks of AIVs in poultry and humans. Therefore, the AIVs in wild birds pose huge threat to poultry industry and human health. To gain a better understanding of the ecology and epidemiology of AIVs in wild birds, we summarize the transmission of AIVs between wild birds, poultry, and humans, the main results of surveillance of AIVs in wild birds worldwide and methods for surveillance, and the types of samples and detection methods for AIVs in wild birds, which would be vital for the effective control of avian influenza and response to possible influenza pandemic.
Animals ; Animals, Wild ; virology ; Birds ; virology ; Humans ; Influenza A virus ; genetics ; isolation & purification ; physiology ; Influenza in Birds ; epidemiology ; transmission ; virology ; Influenza, Human ; epidemiology ; transmission ; virology ; Sentinel Surveillance ; veterinary

Rotaviruses, which are recognized as one of the major etiological agents among infants and young children with diarrhea, consist of three concentric layers of protein capsid with the enclosed double-stranded RNA genome. Rotaviruses infect host cells mainly by identifying the specific receptors on cell surfaces and binding to them. Therefore, receptors are important factors for viruses infecting cells. So far, there have been many receptors found to be involved in rotavirus infection, including sialic acid, integrin, Toll-like receptor, and blood group antigen. This article provides an overview of receptors involved in rotavirus infection.
Animals ; Humans ; Receptors, Virus ; genetics ; metabolism ; Rotavirus ; genetics ; physiology ; Rotavirus Infections ; genetics ; metabolism ; virology

Human bocavirus (HBoV) 1-4 have been detected both in respiratory and stool samples since the first HBoV was discovered in 2005. HBoV-1 is mostly associated with respiratory infection, while HBoV 2-4 are usually associated with intestinal tract infection. A variety of signs and symptoms have been described in patients with HBoV infection, including cough, wheezing, pneumonia, and diarrhea, but the research on pathogenic mechanism of HBoV is limited because HBoV cannot be cultured in vitro due to the lack of appropriate host cells. Three-dimensional epithelial cell culture, reverse genetics, and viral metagenomics are identified as novel tools that may promote the research on pathogenic mechanism of HBoV and the discovery of new viruses. This review summaries currently available diagnostic approaches such as electron microscopy, cell culture, PCR, and immunoassay in order to provide a method reference for indepth research on HBoV.
Animals ; Human bocavirus ; genetics ; growth & development ; isolation & purification ; pathogenicity ; Humans ; Parvoviridae Infections ; diagnosis ; virology ; Viral Proteins ; genetics ; metabolism ; Virology ; methods ; Virulence ; Virus Cultivation

Ebola virus (EBOV) and Marburg virus (MARV) belong to the family Filoviridae. Filoviruses cause severe filovirus hemorrhagic fever (FHF) in humans, with high case fatality rates, and represent potential agents for bioterrorism and biological weapons. It is necessary to keep surveillance of filoviruses, even though there is no report of their isolation and patients in China so far. To characterize MARV morphology, the Lake Victoria marburgvirus--Leiden was stained negatively and observed under a transmission electron microscope which is one of important detection methods for filoviruses in emergencies and bioterrorism. MARV showed pleomorphism, with filamentous, rod-shaped, cobra-like, spherical, and branch-shaped particles of uniform diameter but different lengths. Pleomorphism of negatively stained MARV is summarized in this article, so as to provide useful information for possible electron microscopic identification of filoviruses in China.
Animals ; Humans ; Marburg Virus Disease ; virology ; Marburgvirus ; growth & development ; ultrastructure ; Microscopy, Electron, Transmission ; Virion ; growth & development ; ultrastructure

Bombyx mori nucleopolyhedrovirus (BmNPV) bm47 gene is found in all sequenced lepidopteran nucleopolyhedroviruses (NPVs). It is one of the core genes of NPVs. However, the role of bm47 in the biological cycle of NPV remains unknown. In this study, the Red recombination system was used to knock out bm47 from BmNPV to construct bm47-ko-Bacmid in E. coli BW25113 system. Then bm47 gene was introduced back to the viral genome using the Bac-to-Bac system to create the repair virus bm47-re-Bacmid. TCID50 assay and real-time PCR (qPCR) were used to evaluate the effects of bm47 deletion on viral DNA replication, gene transcription, and protein expression. qPCR results showed that bm47 knock-out had no significant effect on viral DNA replication. However, the qPCR results showed that bm47-ko-Bacmid significantly decreased the transcription levels of early gene lef-3, late gene vp39, and very late gene p10 at 48 h and 72 h after viral transfection of BmN cells (P < 0.05). This work will provide a foundation for further studies on the biological function of BmNPV bm47 in viral replication and transcription.
Animals ; Bombyx ; virology ; Gene Deletion ; Gene Expression Regulation, Viral ; Nucleopolyhedrovirus ; genetics ; physiology ; Transcription, Genetic ; Viral Proteins ; genetics ; metabolism ; Virus Replication

In this study, pEGFP-N1 was chosen as the reporter plasmid and transferred into Ctenopharyngodon idellus kidney (CIK) cells by electroporation, and the optimal electroporation conditions were determined by testing the transfection efficiency with different voltages, pulse times, plasmid amounts, and numbers of shocks. The results showed that the maximum electroporation efficiency was achieved under the following conditions in a 0.2 cm electroporation cuvette containing CIK cells (1.5 x 10(7)/mL, 200 microl): electric voltage 200 V, pulse time 45 ms, plasmid 30 microg, and one electric shock. The total genomic RNA of grass carp reovirus (GCRV) was extracted in this experiment and reversely transcribed into cDNA, which was used to amplify the gene segment of GCRV non-structural protein NS26 using designed specific primers. The PCR product was recombined into pEGFP-N1 vector. The fusion protein EGFP-NS26 was successfully and efficiently expressed in the CIK cells by electroporation, which was confirmed by both fluorescent imaging and Western blot analysis. This experiment laid a foundation for further functional studies of the non-structural protein NS26 of GCRV.
Animals ; Cell Line ; Cyprinidae ; Electroporation ; Fish Diseases ; virology ; Gene Expression ; Kidney ; virology ; Reoviridae ; genetics ; physiology ; Reoviridae Infections ; veterinary ; virology ; Viral Nonstructural Proteins ; genetics ; metabolism

This study aims to construct a eukaryotic expression system for envelope gene of Jaagsiekte sheep retrovirus, observes its localization in 293T cells, and investigates the potential in inducing malignant transformation of NIH3T3 cells. By RT-PCR, the full-length cDNA of envelope gene of Jaagsiekte sheep retrovirus (exJSRV-env) was amplified from the extract of naturally infected sheep lung. The clone of target gene was sub-cloned into eukaryotic expression system pEGFP-C1, and validated by PCR, restriction endonuclease, and sequencing. Bioinformatic analysis concerning biological function and cellular localiza tion of exJSRV-env was also performed. The recombinant clone of exJSRV-env was transfected into 293T cells and NIH3T3 cells by Lipofectamine LTX. The expression and celluar localization in 293T cells were validated by confocal microscopy. Soft agar colony formation assay was employed to test the anchorage-independent growth of NIH3T3. DNA sequencing and restriction enzyme digestion with Kpn I and Hind III indicated the correct construction of the recombinant plasmid, which was named pEGFP-C1/exJSRV-env. Amino acid sequence alignment of exJSRV-env with reference sequences found 85%-100% homogeneity. A YRNM motif was discovered at the cytoplasmic tail of envelope gene, which is exclusively found in exogenous viruses. Phylogenetic tree analysis showed that our clone of exJSRV-env clustered closely with pathogenic exogenous Jaagsiekte sheep retroviruses. Fluorescence microscopy indicated typical membrane localization of exJSRV-env protein. NIH3T3 cells transfected with exJSRV-env lost contact inhibition, and acquired colony forming ability in soft agar. This study indicated that envelope protein of Jaagsiekte sheep retrovirus can induce malignant transformation of mouse fibroblast cell NIH3T3. Discoveries of this study provide a basis for further structural and functional research on Jaagsiekte sheep retrovirus envelope protein.
Amino Acid Sequence ; Animals ; Betaretrovirus ; chemistry ; classification ; genetics ; physiology ; Cell Transformation, Viral ; Green Fluorescent Proteins ; genetics ; metabolism ; Mice ; Molecular Sequence Data ; NIH 3T3 Cells ; Phylogeny ; Retroviridae Infections ; veterinary ; virology ; Sequence Alignment ; Sheep ; Sheep Diseases ; virology ; Transformation, Genetic ; Tumor Virus Infections ; veterinary ; virology ; Viral Envelope Proteins ; chemistry ; genetics ; metabolism