Objective To construct the recombinant human metapneumovirus(hMPV) (defined as rhMPV NL/1/00 GFP) in vitro by reverse genetics technique. Methods BSR-T7 cells were transfected using LipofectAMINE 2000 with the full-length cDNA plasmid, and four major protein expressing plasmids, pCITE-N, pCITE-P, pCITE-M2.1 and pCITE-L. After 3 d, cells were subjected to one -80℃ freeze-thaw cycle to prepare lysates. The supernatant of lysate was used to inoculate Vero-E6 cells. After 1-4 d, cells were found for the obvious development of cytopathic effects under light microscope and green fluoroscopic signals under fluorescence microscope, and were observed up to 10 d. The supernatant were collected to de-tect virus titer. Viral RNA was extracted from the supernatant and reverse transcriptase polymerase chain re-action (RT-PCR) was used to amplify N, F and G genes of rescued virus. Results Cytopathic effects and green fluoroscopic signals was readily and obviously observed after 1-4 d post-inoculation in Vero-E6 cells, then cytopathic effects got worse and green fluoroscopic signals became stronger gradually up to 10 d. The ti-ters of the 1st, 5th, 10th,15th and 20th generation virus ranged from 105.0 to 106.5 TCID50/ml. Amplicons with size of 910 bp (N), 450 bp (F) and 980 bp (G) by RT-PCR were accordant with expectant. Nucleotide sequence analysis of above cDNA fragments showed 100% similarity with reported sequence of hMPV NI/1/00 strain. The recombinant virus was genetically constant and GFP-labeled after 20 passages in Vero-E6 cells. Conclusion Recombined hMPV was successfully rescued by reverse genetics technique. This study lays ground for exploring pathogenesis of hMPV infection and development of hMPV attenuated vac-cines.

Objective To investigate the character and location of a novel gene R049 and its expressed protein in uropathogenic Escherichia coli(UPEC) strain 132 isolated in China. MethodsThe chromosome library of UPEC132 was constructed by a shotgun strategy and the sequence analysis was carried out by a high-throughput pyrophosphate sequencing. Sequence reads were assembled with the Newbler program.The characters of R049-associated specific fragment were analyzed using the bioinformatics methods. Outer and inner membrane proteins of UPEC132 were extracted and then detected by SDS-PAGE and Western blot analysis together with the whole-cell lysates. ResultsThe 169 022 bp contig containing gene R049 was obtained and its sequence was very similar to the chromosome associated sequence of UPEC strain 536. It showed that a 20 773 bp fragment including R049 replaced the pathogenicity island PAI Ⅲ536 of UPEC536 in above 169 022 bp contig. The fragment had a lower GC content (46.97％) and 16 bp direct repeats in two ends. Significantly it also was adjacented to thrW tRNA, insertion element and genes coding integrase. Thus the 20 773 bp fragment was named R049 genome island(R049-GI). There were 25 ORFs in R049-GI, and gene R049 was located in the thirteenth ORF. The results of SDS-PAGE and Western blot revealed gene R049 encoded an outer membrane protein in the size of 47.0× 103. ConclusionGene R049, encoding an outer membrane protein, was a component part of the genome island in UPEC 132 chromosome acquired by horizontal gene transfer.

Objective To clone and express the new gene R049 of uropathogenic Escherichia coli 132.and to investigate the immunopmtective effects of the R049 recombinant protein on mice.Methods The pmkaryotic expression system of gene R049 was constructed by directed cloning.Thereafter,the R049 recombinant protein Was expressed and purified by Ni affinity chromatography.Polyclonal antibody was pre-pared by immunizing BALB/c mice with R049 recombinant protein.The R049 recombinant protein and whole bacterial proteins of UPEC132 were analyzed by SDS-PAGE and Western blot.BALB/c mice were im-munized with R049 recombinant protein before challenged by UPECl32 through urinary tract.Then the differences of urine and renal colony counts between immunization group and control group were compared.Results The recombinant strain E coli BL21(DE3)/pET32a-R049 ORF was constructed successfully,and the relative molecular mass of the R049 recombinant protein was 66.9×103 and its purity was up to 95% af-ter purification.The titer of polyclonal antibody wag≥1:102 400 analyzed by indirect ELISA.Both of the R049 recombinant protein and whole bacterial proteins of UPECl 32 were confirmed to show specffic reactions on the antiserunl throughh Western blot.The animal experiments showed the urine and renal colony counts of immunization group were significantly lower than that of the control group(P<0.01,P<0.05).Conclu-sion The new gene R049 of uropathogenic E.coli 132 had immunopmtective effects on mice and the defini-tive mechanism would be needed to further study.

Objective To investigate the interaction between uropathogenic Escherichia coli (UPEC) and host uroepithelial cells, define the role uroepithelial cells play in initiating and modulating the host response to infection with UPEC strain. Methods The human bladder transitional epithelial EJ cells were evaluated for their capacities to allow the adherence and invasion by UPEC132, a clinical strain isolated from Tianjin, China, and a cDNA microarray for 22 000 human genes was used to identify the gene expression differences between EJ cells infected with UPEC132 and uninfected EJ cells. Results Microscope observation showed that UPEC132 could adhere to EJ cells with the adherence rate of (73.20 ± 5.26)%. And visualization by confocal microscope revealed that this microorganism could be seen within the cells. EJ cells infected with UPEC132 changed mRNA expression of a total of 29 genes, including 28 genes up-regulated and 1 gene down-regulated. Of these, regulators of growth and proliferation, cytokines, and modulators of apoptotic responses were the most prominent. Conclusion The gene expression profiling of EJ cells is affected by the infection of UPEC strain. The differentially expressed genes may contribute to further investigate the interaction of UPEC and uroepithelial cells.

Objective To study the distribution of the specific fragment R049 of uropathogenic E. coli(UPEC) 132 in UPEC and fecal E. coli strains. Methods The specific fragment R049 was amplified by PCR from 20 UPEC strains and 40 fecal E. coli strains, and 5 genes encoding virulence factors (papC, fimH, hly, aer, cnf1) were detected from fragment R049 positive strains. Pulse field gel electronphoresis (PFGE) was applied for isolating the Xba Ⅰ restriction fragments of the genomes of fragment R049 positive strains, and then Southern blot was applied for analyzing the distribution features of the positive hybridization bands by digoxin-labeled R049 ORF probe. Results The specific fragment R049 was amplified from 8 of 20 UPEC strains (40%) and 3 of 40 fecal E. coli strains (7.5%), and statistics analysis showed significant difference (P<0.01). The specific fragment 11049 was closely related with 5 virulence factors of UPEC in the fragment R049 positive strains. Southern blot showed the sizes of positive bands were 150 kb, 15 kb and 240 kb in 3 fecal E. coli strains, 350 kb in 6 of 8 UPEC strains, and 280 kb and 25 kb in the rest two UPEC strains. Conclusion The specific fragment R049 of UPEC132 possessed the feature of clustering distribu-tion in domestic isolated UPEC strains.

In order to ensure the biosafety of the IFN-gamma antiviral activity assay, we used a replication-deficient VSV carrying GFP as an interferon sensitive indicator virus (VSVdeltaG*G). The antiviral activities of porcine IFN-gamma expressed in Escherichia coli and in baculovirus on MDBK cells were assessed. The results showed that the antiviral activity of porcine IFN-gamma expressed in baculovirus could reach 10(5) IU/mL, while the porcine IFN-gamma expressed in E. coli showed some antiviral activity (32 IU/mL) after refolding. The results of the VSVdeltaG*G-based antiviral assay were almost identical to that of the VSV*GFP-based assay, suggesting it is highly feasible to use VSVdeltaG*G as a substitute for VSV*GFP, making assays for IFN-gamma antiviral activity safer and more accurate.
Animals ; Antiviral Agents ; pharmacology ; Baculoviridae ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Interferon-gamma ; biosynthesis ; genetics ; metabolism ; pharmacology ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology ; Swine ; Vesiculovirus ; drug effects ; physiology

Adaptation, Physiological ; Adenosine Monophosphate ; administration & dosage ; analogs & derivatives ; pharmacology ; therapeutic use ; Administration, Intranasal ; Alanine ; administration & dosage ; analogs & derivatives ; pharmacology ; therapeutic use ; Animals ; Betacoronavirus ; genetics ; physiology ; Chlorocebus aethiops ; Coronavirus Infections ; drug therapy ; virology ; Disease Models, Animal ; Female ; Host Specificity ; genetics ; Lung ; pathology ; virology ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mutation, Missense ; Nasal Mucosa ; virology ; Pandemics ; Pneumonia, Viral ; drug therapy ; virology ; RNA, Viral ; administration & dosage ; genetics ; Turbinates ; virology ; Vero Cells ; Viral Load ; Virus Replication