[Objective] The aim of this study was to analyze the sequence characteristics and molecular evolution of ubiquitins encoded by baculoviruses.[Methods]Clustal W software was used for multiple sequence alignment analysi...[Objective] The aim of this study was to analyze the sequence characteristics and molecular evolution of ubiquitins encoded by baculoviruses.[Methods]Clustal W software was used for multiple sequence alignment analysis,and neighbor-joining method（NJ）and maximum parsimony method（MP）were used for the construction of phylogenetic tree.[Results]The baculoviral ubiquitins showed 73%-86% sequence identity to eukaryotic ubiquitin.Two heterogeneous regions of baculoviral ubiquitins were observed：one was the residues from 15-32,the other was located from residues 53 to 60.The else parts were conserved,where many functional amino acids were also observed.Phylogenetic analysis indicated that baculoviral ubiquitins could be divided into three sub-families,including sub-family GV,sub-family I and sub-family II.The molecular evolution of baculoviral ubiquitins might be under negative selection to maintain their functional and structural stability.[Conclusion]The analysis had provided reference for the researches on functional characterization of baculoviral ubiquitins.展开更多
Insect parasitoids and baculoviruses play important roles in the natural and strategic biological control of insects. The two parasites are frequent competitors within common hosts and much research has focused on the...Insect parasitoids and baculoviruses play important roles in the natural and strategic biological control of insects. The two parasites are frequent competitors within common hosts and much research has focused on the negative impact that baculoviral host infections have on parasitoids. This review summarizes the impacts that parasitoids may have on the virulence and spread of lepidopteran baculoviruses. By changing host behavior and development, parasitoids have been shown to decrease baculovirus virulence and productivity within parasitized baculovirus-susceptible hosts; however, studies of the tools used by hymenopteran parasitoids to overcome their hosts'immune systems, suggest that parasitoids may, in some cases, facilitate baculoviral infections in less susceptible hosts. Laboratory and field research have demonstrated that parasitoids can mechanically transmit baculoviruses between insects, and in this way, increase the efficacy of the viruses. Instances of new, more virulent isolates of baculoviruses have been recorded from specifically parasitoid-targeted hosts suggesting other possible benefits from the transmission or activation of baculoviruses by parasitoids.展开更多
Protein nanotubes(PNTs)can be regarded as two-dimensional(2D)lattices with p1 or p2 symmetry rolled into tubes.However,attempts to re-assemble their building blocks into stable 2D nanomaterials often fail.Here,startin...Protein nanotubes(PNTs)can be regarded as two-dimensional(2D)lattices with p1 or p2 symmetry rolled into tubes.However,attempts to re-assemble their building blocks into stable 2D nanomaterials often fail.Here,starting from two baculoviral capsid proteins,we screened protein variants for the in vitro assembly of various nanotubes and nanosheets.These high-order assemblies were structurally characterized by cryo-electron microscopy techniques.Interfacial analysis of three groups of PNTs revealed that helical heterogeneity is largely the result of the redundancy of p2 symmetry-related contacting interfaces.The assembled nanosheets showed similar interfacial networks to their nanotubular counterparts.In addition,foreign macromolecules could be efficiently displayed on the sizecontrollable double-layered nanosheets.This study sheds light on the rational design of flexible nanosheets,and it also provides novel 2D protein scaffolds for developing biocompatible materials.展开更多
Entomopathogenic viruses,such as baculoviruses and cypoviruses,have been employed as biological pesticides against agricultural and forestry pests.However,their susceptibility to inactivation under field UV radiation ...Entomopathogenic viruses,such as baculoviruses and cypoviruses,have been employed as biological pesticides against agricultural and forestry pests.However,their susceptibility to inactivation under field UV radiation has hindered their broader application.In this study,we effectively improved the UV resistance of insect virus occlusion bodies(OBs)by coating their surfaces with silica nanoparticles(SiO_(2)NPs).Monodisperse SiO_(2)NPs with uniform size distribution and excellent colloidal stability were synthesized using the Stober method.Subsequent amination modification of the SiO_(2)NPs with a silane coupling agent shifted their isoelectric point from 3.2 to 8.1.This modification imparted a strong positive charge to the NPs within the pH range of 4.5-5.5,while the OBs of insect viruses remained negatively charged in this range.Consequently,the amino-functionalized SiO_(2)NPs were successfully coated onto the surfaces of OBs of three representative insect viruses:nucleopolyhedrovirus,granulovirus,and cypovirus,through electrostatic interactions.Laboratory bioassays confirmed that Mamestra brassicae multiple nucleopolyhedrovirus(MbMNPV)coated with SiO_(2)-NH2 NPs retained its native viral pathogenicity against Spodoptera exigua larvae under normal laboratory condition,while it demonstrated 2.299-2.712 folds higher potency than MbMNPV physically mixed with unmodified SiO_(2)NPs after UV irradiation.Outdoor trials revealed that SiO_(2)-NH_(2)NPs coating significantly improved the survival time of MbMNPV,with the median survival time increased from 1.43 days to 5.15 days.This nanoparticle coating strategy establishes a robust platform for developing photostable biopesticides while preserving their ecological safety profiles.The modular nature of this approach suggests its broad applicability across different entomopathogenic virus formulations.展开更多
Since its discovery in the 1980s,the insect cell-baculovirus expression vector system(IC-BEVS)has been widely used in biomedical applications,such as recombinant protein expression,drug screening,vaccine development,g...Since its discovery in the 1980s,the insect cell-baculovirus expression vector system(IC-BEVS)has been widely used in biomedical applications,such as recombinant protein expression,drug screening,vaccine development,gene therapy and so on[1].As a eukaryotic system,IC-BEVS has great development prospects due to its advantages such as high safety,simple operation,simultaneous expression of multi-subunit proteins,and suitability for large-scale cultivation[2].展开更多
Large DNA viruses normally have complex structures with many of protein components derived from both viral and host origins. The development in proteomics, especially mass spectrometry identification techniques provid...Large DNA viruses normally have complex structures with many of protein components derived from both viral and host origins. The development in proteomics, especially mass spectrometry identification techniques provide powerful tools for analyzing large viruses. In this review, we have summarized the recent achievements on proteomic studies of large DNA viruses, such as herpesvirus, poxvirus, nimavirus and baculoviruse. The proteomics of baculovirus occlusion-derived virions (ODV) were emphasized. Different mass spectrometry techniques used on various baculoviruses were introduced, and the identified structurally associated proteins of baculoviruses are summarized.展开更多
AIM： Enterovirus 71 （EV71） has been implicated as the etiological agent responsible for the recent outbreaks of hand, foot and mouth disease associated with severe neurological diseases in the Asia-Pacific region. ...AIM： Enterovirus 71 （EV71） has been implicated as the etiological agent responsible for the recent outbreaks of hand, foot and mouth disease associated with severe neurological diseases in the Asia-Pacific region. METHODS： The assembly process was hypothesized to occur via an orchestrated proteolytic processing of the P1 precursor by the viral protease 3CD. To test this hypothesis, we constructed 3 recombinant baculoviruses： Bac-P1 expressing P1; Bac-3CD expressing 3CD; and Bac-P1-3CD co-expressing P1 and 3CD. RESULTS： Both single infection by Bac-P1-3CD and coinfection by Bac-P1 and Bac-3CD resulted in correct cleavage of P1 to yield individual proteins VP0, VP1 and VP3, while the former approach yielded higher VLP production. In the cells, the structural proteins selfassembled into clusters of virus-like particles （VLP） resembling the authentic EV71 particle aggregates. After ultracentrifugation purification, the dispersed VLPs were indistinguishable from the authentic virus in size, appearance, composition and surface epitopes, as determined by SDS-PAGE, Western blot, transmission electron microscopy and immunogold labeling. CONCLUSION： Our data, for the first time, suggest that in insect cells EV71 structural proteins adopt a processing and assembly pathway similar to poliovirus assembly. The preservation of particle morphology and composition suggest that the VLP may be a valuable vaccine candidate to prevent EV71 epidemics.展开更多
As one of the most important aquatic fish,Micropterus salmoides suffers lethal and epidemic disease caused by rhabdovirus at the juvenile stage.In this study,a new strain of M.salmoides rhabdovirus(MSRV)was isolated f...As one of the most important aquatic fish,Micropterus salmoides suffers lethal and epidemic disease caused by rhabdovirus at the juvenile stage.In this study,a new strain of M.salmoides rhabdovirus(MSRV)was isolated from Yuhang,Zhejiang Province,China,and named MSRV-YH01.The virus infected the grass carp ovary(GCO)cell line and displayed virion particles with atypical bullet shape,300–500 nm in length and 100–200 nm in diameter under transmission electron microscopy.The complete genome sequence of this isolate was determined to include 11 526 nucleotides and to encode five classical structural proteins.The construction of the phylogenetic tree indicated that this new isolate is clustered into the Vesiculovirus genus and most closely related to the Siniperca chuatsi rhabdovirus.To explore the potential for a vaccine against MSRV,a glycoprotein(1–458 amino acid residues)of MSRV-YH01 was successfully amplified and cloned into the plasmid pFastBac1.The high-purity recombinant bacmid-glycoprotein was obtained from DH10Bac through screening and identification.Based on polymerase chain reaction(PCR),western blot,and immunofluorescence assay,recombinant virus,including the MSRV-YH01 glycoprotein gene,was produced by transfection of SF9 cells using the pFastBac1-gE2,and then repeatedly amplified to express the glycoprotein protein.We anticipate that this recombinant bacmid system could be used to challenge the silkworm and develop a corresponding oral vaccine for fish.展开更多
Objective To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Methods Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were press...Objective To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Methods Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred μL 106 TCID50/mL SARS-CoV, 100 μL 106 PFU/mL recombinant baculovirus expressing hamster’s prion protein (haPrP) protein and roughly 106 E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. Results After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. Conclusion Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.展开更多
AIM: To study the inhibitory effect of baculovirus- mediated normal epithelial cell specific-1 (NES1) gene therapy on gastric cancer (GC) in vitro and in vivo. METHODS: We first constructed recombinant baculovirus vec...AIM: To study the inhibitory effect of baculovirus- mediated normal epithelial cell specific-1 (NES1) gene therapy on gastric cancer (GC) in vitro and in vivo. METHODS: We first constructed recombinant baculovirus vectors and then transfected them into gastric cancer cells (SGC-7901). Efficiency of the baculovirus for gene transfer into SGC-7901 cells and cell growth curves were detected by fluorescence microscopy, Western blot and 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro, respectively. The therapeutic effect of this gene therapy on GC was confirmed in xenografted nude mice. Tumor growth was determined by tumor volume, and expression of NES1 in tumor was analyzed by immunohistochemistry. RESULTS: Baculovirus vectors were successfully transfected into SGC-7901 cells. SGC-7901 cells transfected with the NES1 gene inhibited cell growth. In the Bac-NES1 treated group, tumor growth was significantly reduced with a high level of NES1 expression CONCLUSION: Baculovirus-mediated NES1 gene can be used in gene therapy for GC.展开更多
AIM： To study the baculovirus/mammalian cell system for efficient expression of functional large hepatitis delta antigen （L-HDAg）. METHODS： A recombinant baculovirus expressing histidine-tagged L-HDAg （L-HDAgH） ...AIM： To study the baculovirus/mammalian cell system for efficient expression of functional large hepatitis delta antigen （L-HDAg）. METHODS： A recombinant baculovirus expressing histidine-tagged L-HDAg （L-HDAgH） was constructed to transduce baby hamster kidney （BHK） cells by a simplified transduction protocol. RESULTS： The recombinant baculovirus transduced BHK cells with efficiencies higher than 90% as determined by flow cytometry. The expression level was significantly higher than that obtained by plasmid transfection and was further enhanced 3-fold to around 19 pg/cell by the addition of 10 mmol/L sodium butyrate. Importantly, the expressed L-HDAgH was localized to the cell nucleus and correctly isoprenylated as determined by immunofluorescence labeling and confocal microscopy. Moreover, L-HDAgH interacted with hepatitis B surface antigen to form virus-like particles. CONCLUSION： The fusion with histidine tags as well as overexpression of L-HDAgH in the baculovirus-transduced BHK cells does not impair the biological functions. Taken together, the baculovirus/mammalian cell system offers an attractive alternative for high level expression of L-HDAgH or other proteins that require extensive posttranslational modifications.展开更多
Hepatitis-hydropericardium syndrome(HHS)is an infectious disease caused by fowl adenovirus serotype 4(FAdV-4).Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculo...Hepatitis-hydropericardium syndrome(HHS)is an infectious disease caused by fowl adenovirus serotype 4(FAdV-4).Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculovirus expression system to develop candidate subunit vaccines.However,the protective efficiency of baculovirus-expressed penton base protein has not been assessed.In this study,two recombinant capsid proteins,penton base and fiber-2,were constructed.And then,penton base and fiber-2 were administrated alone or together to specific pathogen-free(SPF)chickens at 14 days of life and boosted at 28 days of life.At 42 days of life,the immunized groups and the control group were challenged with FAdV-4 virulent strain.Results show that inoculating penton base or penton base+fiber-2 provided 100%protection to the chickens.All groups vaccinated with the recombinant protein produced detectable antibodies and showed no apparent lesions.Thus,baculovirus-expressed penton base protein is a promising candidate subunit vaccine.展开更多
AIM:To investigate the feasibility of radionuclide therapy of colon tumor cells by baculovirus vector-mediated transfer of the sodium/iodide symporter(NIS) gene.METHODS:A recombinant baculovirus plasmid carrying the N...AIM:To investigate the feasibility of radionuclide therapy of colon tumor cells by baculovirus vector-mediated transfer of the sodium/iodide symporter(NIS) gene.METHODS:A recombinant baculovirus plasmid carrying the NIS gene was constructed,and the viruses(BacNIS) were prepared using the Bac-to-Bac system.The infection efficiency in the colon cancer cell line SW1116 of a green fluorescent protein(GFP) expressing baculovirus(Bac-GFP) at different multiplicities of infection(MOI) with various concentrations of sodium butyrate was determined by flow cytometry.An in vitro cytotoxicity assay was also conducted after infection of SW1116 cells with Bac-NIS.Iodine uptake of Bac-NIS infected SW1116 cells and inhibition of this uptake by sodium perchlorate was examined,and the effect of Bac-NISmediated 131 I in killing tumor cells was evaluated by cell colony formation tests.RESULTS:Infection and transgene expression in SW1116with Bac-GFP were significantly enhanced by sodium butyrate,as up to 72% of SW1116 cells were infected with the virus at MOI of 400 and sodium butyrate at 0.5 mmol/L.No obvious cytotoxicity was observed under these conditions.Infection of SW1116 with Bac-NIS allowed uptake of 131 I in these tumor cells,which could be inhibited by sodium perchlorate.The viability of SW1116 cells infected with Bac-NIS was significantly lower than with Bac-GFP,suggesting that NIS gene-mediated 131 I uptake could specifically kill tumor cells.CONCLUSION:Baculovirus vector-mediated NIS gene therapy is a potential approach for treatment of colon cancer.展开更多
The newly emerged mosquito-borne Zika virus(ZIKV) strains pose a global challenge owing to its ability to cause microcephaly and neurological disorders. Several ZIKV vaccine candidates have been proposed, including in...The newly emerged mosquito-borne Zika virus(ZIKV) strains pose a global challenge owing to its ability to cause microcephaly and neurological disorders. Several ZIKV vaccine candidates have been proposed, including inactivated and live attenuated virus vaccines, vector-based vaccines, DNA and RNA vaccines. These have been shown to be efficacious in preclinical studies in mice and nonhuman primates, but their use will potentially be a threat to immunocompromised individuals and pregnant women. Virus-like particles(VLPs) are empty particles composed merely of viral proteins, which can serve as a safe and valuable tool for clinical prevention and treatment strategies. In this study, we used a new strategy to produce ZIKV VLPs based on the baculovirus expression system and demonstrated the feasibility of their use as a vaccine candidate. The pre-membrane(prM) and envelope(E) proteins were co-expressed in insect cells and selfassembled into particles similar to ZIKV. We found that the ZIKV VLPs could be quickly and easily prepared in large quantities using this system. The VLPs were shown to have good immunogenicity in immunized mice, as they stimulated high levels of virus neutralizing antibody titers, ZIKV-specific IgG titers and potent memory T cell responses. Thus, the baculovirus-based ZIKV VLP vaccine is a safe, effective and economical vaccine candidate for use against ZIKV.展开更多
The double-shelled grass carp reovirus （GCRV） is capable of endogenous RNA transcription and processing.Genome sequence analysis has revealed that the protein VP2,encoded by gene segment 2 （S2）,is the putative RNA...The double-shelled grass carp reovirus （GCRV） is capable of endogenous RNA transcription and processing.Genome sequence analysis has revealed that the protein VP2,encoded by gene segment 2 （S2）,is the putative RNA-dependent RNA polymerase （RdRp）.In previous work,we have ex-pressed the functional region of VP2 that is associated with RNA polymerase activity （denoted as rVP2390-900） in E.coil and have prepared a polyclonal antibody against VP2.To characterize the GCRV RNA polymerase,a recombinant full-length VP2 （rVP2） was first constructed and expressed in a baculovirus system,as a fusion protein with an attached His-tag.Immunofluorescence （IF） assays,together with immunoblot （IB） analyses from both expressed cell extracts and purified Histagged rVP2,showed that rVP2 was successfully expressed in Sf9 cells.Further characterization of the replicase activity showed that purified rVP2 and GCRV particles exhibited poly（C）-dependent poly（G） polymerase activity.The RNA enzymatic activity required the divalent cation Mg2＋,and was optimal at 28 ℃.The results provide a foundation for further studies on the RNA polymerases of aquareoviruses during viral transcription and replication.展开更多
基金Supported by China Postdoctoral Scientific Foundation(201004713-87)Natural Science Foundation for Universities of Jiangsu Province(07KJB180013)Foundation for Talented Man in Jiangsu University(05JDG048)~~
文摘[Objective] The aim of this study was to analyze the sequence characteristics and molecular evolution of ubiquitins encoded by baculoviruses.[Methods]Clustal W software was used for multiple sequence alignment analysis,and neighbor-joining method（NJ）and maximum parsimony method（MP）were used for the construction of phylogenetic tree.[Results]The baculoviral ubiquitins showed 73%-86% sequence identity to eukaryotic ubiquitin.Two heterogeneous regions of baculoviral ubiquitins were observed：one was the residues from 15-32,the other was located from residues 53 to 60.The else parts were conserved,where many functional amino acids were also observed.Phylogenetic analysis indicated that baculoviral ubiquitins could be divided into three sub-families,including sub-family GV,sub-family I and sub-family II.The molecular evolution of baculoviral ubiquitins might be under negative selection to maintain their functional and structural stability.[Conclusion]The analysis had provided reference for the researches on functional characterization of baculoviral ubiquitins.
文摘Insect parasitoids and baculoviruses play important roles in the natural and strategic biological control of insects. The two parasites are frequent competitors within common hosts and much research has focused on the negative impact that baculoviral host infections have on parasitoids. This review summarizes the impacts that parasitoids may have on the virulence and spread of lepidopteran baculoviruses. By changing host behavior and development, parasitoids have been shown to decrease baculovirus virulence and productivity within parasitized baculovirus-susceptible hosts; however, studies of the tools used by hymenopteran parasitoids to overcome their hosts'immune systems, suggest that parasitoids may, in some cases, facilitate baculoviral infections in less susceptible hosts. Laboratory and field research have demonstrated that parasitoids can mechanically transmit baculoviruses between insects, and in this way, increase the efficacy of the viruses. Instances of new, more virulent isolates of baculoviruses have been recorded from specifically parasitoid-targeted hosts suggesting other possible benefits from the transmission or activation of baculoviruses by parasitoids.
基金supported by the National Key Research and Development Program of China(2022YFC2303300 to S.C.)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0490000 to S.C.)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022341 to G.R.)the Major Project of the Guangzhou National Laboratory(GZNL2024A01010 to G.R.).
文摘Protein nanotubes(PNTs)can be regarded as two-dimensional(2D)lattices with p1 or p2 symmetry rolled into tubes.However,attempts to re-assemble their building blocks into stable 2D nanomaterials often fail.Here,starting from two baculoviral capsid proteins,we screened protein variants for the in vitro assembly of various nanotubes and nanosheets.These high-order assemblies were structurally characterized by cryo-electron microscopy techniques.Interfacial analysis of three groups of PNTs revealed that helical heterogeneity is largely the result of the redundancy of p2 symmetry-related contacting interfaces.The assembled nanosheets showed similar interfacial networks to their nanotubular counterparts.In addition,foreign macromolecules could be efficiently displayed on the sizecontrollable double-layered nanosheets.This study sheds light on the rational design of flexible nanosheets,and it also provides novel 2D protein scaffolds for developing biocompatible materials.
基金supported by the Key R&D Program of Ningxia Hui Autonomous Region(2023BCF01045).
文摘Entomopathogenic viruses,such as baculoviruses and cypoviruses,have been employed as biological pesticides against agricultural and forestry pests.However,their susceptibility to inactivation under field UV radiation has hindered their broader application.In this study,we effectively improved the UV resistance of insect virus occlusion bodies(OBs)by coating their surfaces with silica nanoparticles(SiO_(2)NPs).Monodisperse SiO_(2)NPs with uniform size distribution and excellent colloidal stability were synthesized using the Stober method.Subsequent amination modification of the SiO_(2)NPs with a silane coupling agent shifted their isoelectric point from 3.2 to 8.1.This modification imparted a strong positive charge to the NPs within the pH range of 4.5-5.5,while the OBs of insect viruses remained negatively charged in this range.Consequently,the amino-functionalized SiO_(2)NPs were successfully coated onto the surfaces of OBs of three representative insect viruses:nucleopolyhedrovirus,granulovirus,and cypovirus,through electrostatic interactions.Laboratory bioassays confirmed that Mamestra brassicae multiple nucleopolyhedrovirus(MbMNPV)coated with SiO_(2)-NH2 NPs retained its native viral pathogenicity against Spodoptera exigua larvae under normal laboratory condition,while it demonstrated 2.299-2.712 folds higher potency than MbMNPV physically mixed with unmodified SiO_(2)NPs after UV irradiation.Outdoor trials revealed that SiO_(2)-NH_(2)NPs coating significantly improved the survival time of MbMNPV,with the median survival time increased from 1.43 days to 5.15 days.This nanoparticle coating strategy establishes a robust platform for developing photostable biopesticides while preserving their ecological safety profiles.The modular nature of this approach suggests its broad applicability across different entomopathogenic virus formulations.
文摘Since its discovery in the 1980s,the insect cell-baculovirus expression vector system(IC-BEVS)has been widely used in biomedical applications,such as recombinant protein expression,drug screening,vaccine development,gene therapy and so on[1].As a eukaryotic system,IC-BEVS has great development prospects due to its advantages such as high safety,simple operation,simultaneous expression of multi-subunit proteins,and suitability for large-scale cultivation[2].
基金The grants of National Science Foundation of China (30630002, 30670078)973 Program(2009CB118903)Programme Strategic Scientific Alliances between China and the Netherlands (2008AA000238)
文摘Large DNA viruses normally have complex structures with many of protein components derived from both viral and host origins. The development in proteomics, especially mass spectrometry identification techniques provide powerful tools for analyzing large viruses. In this review, we have summarized the recent achievements on proteomic studies of large DNA viruses, such as herpesvirus, poxvirus, nimavirus and baculoviruse. The proteomics of baculovirus occlusion-derived virions (ODV) were emphasized. Different mass spectrometry techniques used on various baculoviruses were introduced, and the identified structurally associated proteins of baculoviruses are summarized.
基金Supported by the National Science Council,No.93-2214-E-007-016 Ministry of Economic Affairs,No.93-EC-17A-17S1-0009
文摘AIM： Enterovirus 71 （EV71） has been implicated as the etiological agent responsible for the recent outbreaks of hand, foot and mouth disease associated with severe neurological diseases in the Asia-Pacific region. METHODS： The assembly process was hypothesized to occur via an orchestrated proteolytic processing of the P1 precursor by the viral protease 3CD. To test this hypothesis, we constructed 3 recombinant baculoviruses： Bac-P1 expressing P1; Bac-3CD expressing 3CD; and Bac-P1-3CD co-expressing P1 and 3CD. RESULTS： Both single infection by Bac-P1-3CD and coinfection by Bac-P1 and Bac-3CD resulted in correct cleavage of P1 to yield individual proteins VP0, VP1 and VP3, while the former approach yielded higher VLP production. In the cells, the structural proteins selfassembled into clusters of virus-like particles （VLP） resembling the authentic EV71 particle aggregates. After ultracentrifugation purification, the dispersed VLPs were indistinguishable from the authentic virus in size, appearance, composition and surface epitopes, as determined by SDS-PAGE, Western blot, transmission electron microscopy and immunogold labeling. CONCLUSION： Our data, for the first time, suggest that in insect cells EV71 structural proteins adopt a processing and assembly pathway similar to poliovirus assembly. The preservation of particle morphology and composition suggest that the VLP may be a valuable vaccine candidate to prevent EV71 epidemics.
文摘As one of the most important aquatic fish,Micropterus salmoides suffers lethal and epidemic disease caused by rhabdovirus at the juvenile stage.In this study,a new strain of M.salmoides rhabdovirus(MSRV)was isolated from Yuhang,Zhejiang Province,China,and named MSRV-YH01.The virus infected the grass carp ovary(GCO)cell line and displayed virion particles with atypical bullet shape,300–500 nm in length and 100–200 nm in diameter under transmission electron microscopy.The complete genome sequence of this isolate was determined to include 11 526 nucleotides and to encode five classical structural proteins.The construction of the phylogenetic tree indicated that this new isolate is clustered into the Vesiculovirus genus and most closely related to the Siniperca chuatsi rhabdovirus.To explore the potential for a vaccine against MSRV,a glycoprotein(1–458 amino acid residues)of MSRV-YH01 was successfully amplified and cloned into the plasmid pFastBac1.The high-purity recombinant bacmid-glycoprotein was obtained from DH10Bac through screening and identification.Based on polymerase chain reaction(PCR),western blot,and immunofluorescence assay,recombinant virus,including the MSRV-YH01 glycoprotein gene,was produced by transfection of SF9 cells using the pFastBac1-gE2,and then repeatedly amplified to express the glycoprotein protein.We anticipate that this recombinant bacmid system could be used to challenge the silkworm and develop a corresponding oral vaccine for fish.
基金This work was supported by the National High-Technology Research and Development Program of China (863 Program) 2003AA208402 and2003AA208201.
文摘Objective To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Methods Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred μL 106 TCID50/mL SARS-CoV, 100 μL 106 PFU/mL recombinant baculovirus expressing hamster’s prion protein (haPrP) protein and roughly 106 E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. Results After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. Conclusion Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.
基金The Doctoral Fund from the Ministry of Education of China, No. BXJ0710
文摘AIM: To study the inhibitory effect of baculovirus- mediated normal epithelial cell specific-1 (NES1) gene therapy on gastric cancer (GC) in vitro and in vivo. METHODS: We first constructed recombinant baculovirus vectors and then transfected them into gastric cancer cells (SGC-7901). Efficiency of the baculovirus for gene transfer into SGC-7901 cells and cell growth curves were detected by fluorescence microscopy, Western blot and 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro, respectively. The therapeutic effect of this gene therapy on GC was confirmed in xenografted nude mice. Tumor growth was determined by tumor volume, and expression of NES1 in tumor was analyzed by immunohistochemistry. RESULTS: Baculovirus vectors were successfully transfected into SGC-7901 cells. SGC-7901 cells transfected with the NES1 gene inhibited cell growth. In the Bac-NES1 treated group, tumor growth was significantly reduced with a high level of NES1 expression CONCLUSION: Baculovirus-mediated NES1 gene can be used in gene therapy for GC.
基金Supported by National Health Research Institutes (NHRI-EX94-9412EI) VTY Joint Research Program, Tsou's Foundation (VGHUST94-P6-32)
文摘AIM： To study the baculovirus/mammalian cell system for efficient expression of functional large hepatitis delta antigen （L-HDAg）. METHODS： A recombinant baculovirus expressing histidine-tagged L-HDAg （L-HDAgH） was constructed to transduce baby hamster kidney （BHK） cells by a simplified transduction protocol. RESULTS： The recombinant baculovirus transduced BHK cells with efficiencies higher than 90% as determined by flow cytometry. The expression level was significantly higher than that obtained by plasmid transfection and was further enhanced 3-fold to around 19 pg/cell by the addition of 10 mmol/L sodium butyrate. Importantly, the expressed L-HDAgH was localized to the cell nucleus and correctly isoprenylated as determined by immunofluorescence labeling and confocal microscopy. Moreover, L-HDAgH interacted with hepatitis B surface antigen to form virus-like particles. CONCLUSION： The fusion with histidine tags as well as overexpression of L-HDAgH in the baculovirus-transduced BHK cells does not impair the biological functions. Taken together, the baculovirus/mammalian cell system offers an attractive alternative for high level expression of L-HDAgH or other proteins that require extensive posttranslational modifications.
基金supported by the National Key Research and Development Program of China (2016YFD0500801)
文摘Hepatitis-hydropericardium syndrome(HHS)is an infectious disease caused by fowl adenovirus serotype 4(FAdV-4).Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculovirus expression system to develop candidate subunit vaccines.However,the protective efficiency of baculovirus-expressed penton base protein has not been assessed.In this study,two recombinant capsid proteins,penton base and fiber-2,were constructed.And then,penton base and fiber-2 were administrated alone or together to specific pathogen-free(SPF)chickens at 14 days of life and boosted at 28 days of life.At 42 days of life,the immunized groups and the control group were challenged with FAdV-4 virulent strain.Results show that inoculating penton base or penton base+fiber-2 provided 100%protection to the chickens.All groups vaccinated with the recombinant protein produced detectable antibodies and showed no apparent lesions.Thus,baculovirus-expressed penton base protein is a promising candidate subunit vaccine.
基金Supported by Grants from the National Natural Science Foundation of China,No.30570525the Shanghai Leading Academic Discipline Project,No.S30203
文摘AIM:To investigate the feasibility of radionuclide therapy of colon tumor cells by baculovirus vector-mediated transfer of the sodium/iodide symporter(NIS) gene.METHODS:A recombinant baculovirus plasmid carrying the NIS gene was constructed,and the viruses(BacNIS) were prepared using the Bac-to-Bac system.The infection efficiency in the colon cancer cell line SW1116 of a green fluorescent protein(GFP) expressing baculovirus(Bac-GFP) at different multiplicities of infection(MOI) with various concentrations of sodium butyrate was determined by flow cytometry.An in vitro cytotoxicity assay was also conducted after infection of SW1116 cells with Bac-NIS.Iodine uptake of Bac-NIS infected SW1116 cells and inhibition of this uptake by sodium perchlorate was examined,and the effect of Bac-NISmediated 131 I in killing tumor cells was evaluated by cell colony formation tests.RESULTS:Infection and transgene expression in SW1116with Bac-GFP were significantly enhanced by sodium butyrate,as up to 72% of SW1116 cells were infected with the virus at MOI of 400 and sodium butyrate at 0.5 mmol/L.No obvious cytotoxicity was observed under these conditions.Infection of SW1116 with Bac-NIS allowed uptake of 131 I in these tumor cells,which could be inhibited by sodium perchlorate.The viability of SW1116 cells infected with Bac-NIS was significantly lower than with Bac-GFP,suggesting that NIS gene-mediated 131 I uptake could specifically kill tumor cells.CONCLUSION:Baculovirus vector-mediated NIS gene therapy is a potential approach for treatment of colon cancer.
基金supported by the Science and Technology Basic Work Program (2013FY113500) from the Ministry of Science and Technology of Chinathe strategic priority research program of the Chinese Academy of Sciences (ZDRW-ZS2016-4)
文摘The newly emerged mosquito-borne Zika virus(ZIKV) strains pose a global challenge owing to its ability to cause microcephaly and neurological disorders. Several ZIKV vaccine candidates have been proposed, including inactivated and live attenuated virus vaccines, vector-based vaccines, DNA and RNA vaccines. These have been shown to be efficacious in preclinical studies in mice and nonhuman primates, but their use will potentially be a threat to immunocompromised individuals and pregnant women. Virus-like particles(VLPs) are empty particles composed merely of viral proteins, which can serve as a safe and valuable tool for clinical prevention and treatment strategies. In this study, we used a new strategy to produce ZIKV VLPs based on the baculovirus expression system and demonstrated the feasibility of their use as a vaccine candidate. The pre-membrane(prM) and envelope(E) proteins were co-expressed in insect cells and selfassembled into particles similar to ZIKV. We found that the ZIKV VLPs could be quickly and easily prepared in large quantities using this system. The VLPs were shown to have good immunogenicity in immunized mice, as they stimulated high levels of virus neutralizing antibody titers, ZIKV-specific IgG titers and potent memory T cell responses. Thus, the baculovirus-based ZIKV VLP vaccine is a safe, effective and economical vaccine candidate for use against ZIKV.
基金supported by funding from the National Natural Science Foundation of China (grants: 31172434, 31372565)
文摘The double-shelled grass carp reovirus （GCRV） is capable of endogenous RNA transcription and processing.Genome sequence analysis has revealed that the protein VP2,encoded by gene segment 2 （S2）,is the putative RNA-dependent RNA polymerase （RdRp）.In previous work,we have ex-pressed the functional region of VP2 that is associated with RNA polymerase activity （denoted as rVP2390-900） in E.coil and have prepared a polyclonal antibody against VP2.To characterize the GCRV RNA polymerase,a recombinant full-length VP2 （rVP2） was first constructed and expressed in a baculovirus system,as a fusion protein with an attached His-tag.Immunofluorescence （IF） assays,together with immunoblot （IB） analyses from both expressed cell extracts and purified Histagged rVP2,showed that rVP2 was successfully expressed in Sf9 cells.Further characterization of the replicase activity showed that purified rVP2 and GCRV particles exhibited poly（C）-dependent poly（G） polymerase activity.The RNA enzymatic activity required the divalent cation Mg2＋,and was optimal at 28 ℃.The results provide a foundation for further studies on the RNA polymerases of aquareoviruses during viral transcription and replication.
