In this study, a 15-mer phage display peptide library was employed to pan against human rotavirus immobilized on solid phase. 4 different peptides were selected and could bind with rotavirus particles specifically. Plaque reduction neutralization test and MTT analysis results indicated that 3 of the peptides can inhibit rotavirus infecting in vitro. A peptide which sequence is QSNPIHIITNTRNHP showed the best efficiency--93% neutralization infectivity. Two other peptides, A and B, showed 40% and 50% neutralization infectivity respectively. Amino sequence analysis results indicate the 3 peptides containing 2 conserved motifs: SNPIHII and NIP. No putative trypsin hydrolysis site was found in C peptide, however, 4 and 3 potential sites were found in A and B peptides respectively. Using trypsin inhibitor, both A and B peptides showed the similar antiviral effect as that of C peptide. It suggests that the intactness of the 2 conserved motifs play an important role in counteracting virus infection. According to the results of this study, peptide C is hopeful to be exploited as an antiviral peptide drug.
Amino Acid Sequence ; Animals ; Antiviral Agents ; isolation & purification ; pharmacology ; Cell Line ; Cell Survival ; drug effects ; Dose-Response Relationship, Drug ; Drug Evaluation, Preclinical ; Humans ; Molecular Sequence Data ; Neutralization Tests ; Peptide Library ; Peptides ; chemistry ; immunology ; pharmacology ; Protein Binding ; Rotavirus ; drug effects ; growth & development ; immunology ; Sequence Analysis, Protein ; Viral Plaque Assay

Based on site-specific transposition of an expression cassette into a baculovirus shuttle vector (Bacmid) which propagated in Escherichia coli, the Bac-to-Bac System provides a rapid and efficient method to generate recombinant baculoviruses and is widely used for high level expression of heterologous proteins. And the efficiency of recombinant baculovirus infecting cells plays an important role on the protein expression. In this study, we introduced an EGFP expression cassette driven by polyhedrin promoter into the p74 locus of Bacmid by homologous recombination. The target Bacmid-egfp was then transformed into E. coli DH10B containing the transposition helper plasmid to gain a new transposition receipt strain E. coli DH10Bac-egfp. Because of the intact attTn7 sites and lacZ', target gene cloned in a pFastBac vector can be transposed into the Bacmid-egfp shutter vector to construct recombinant baculovirus, which would allow the tracing of the target protein expression and the recombinant Bacmid transfection or recombinant baculoviral infection under fluorescence microscopes. Recombinant virus Bac-egfp-DsRed was constructed by transposing DsRed into the Bacmid-egfp in E. coliDHl0Bac-egfp, and the Sf9 cells infected with the recombinant virus expressed DsRed and EGFP efficiently. Another protein IL-6 fused with 6 x his tag was expressed and purified sucessfully from Sf9 cells infected with recombinant virus Bac-egfp-6 x his-IL6 constructed by the improved Bac-to-Bac system.
Animals ; Baculoviridae ; genetics ; Green Fluorescent Proteins ; genetics ; Interleukin-6 ; biosynthesis ; genetics ; Plasmids ; Polymerase Chain Reaction ; Recombinant Proteins ; biosynthesis ; Spodoptera

E.coli single-stranded DNA-binding protein (SSB) plays an important role in replication, recombination and repair of DNA and is thus crucial for the survival of the bacteria.We described a high expression and efficient purification scheme and kinetic assay of interaction with its substrate, single-stranded DNA (ssDNA). A ssb gene (537 bp) for encoding SSB was obtained by PCR amplification from E.coli K-12 genome. The expression vector of the fusion protein SSB was constructed by attaching ssb gene to pQE30. SSB fusion protein was expressed in M15 E.coli strain induced by IPTG. SDS-PAGE analysis revealed that the expected protein with a molecular weight 20.6kDa was soluble and amounted to about 30% of the total bacterial protein. SSB protein was purified by immobilized metal (Ni2+) chelation affinity chromatography and the purity was about 90%. The resulting SSB protein was a correctly folded tetramer analyzed by gel filtration. It could bind ssDNA with equilibrium dissociation constant (KD) of 4.79×10-7 mol/L as determined by surface plasmon resonance.

Adult ; Aged ; Aged, 80 and over ; Esophageal and Gastric Varices ; complications ; Female ; Gastrointestinal Hemorrhage ; etiology ; Humans ; Logistic Models ; Male ; Middle Aged ; Young Adult

OBJECTIVETo study the prevalence of severe acute respiratory syndrome coronavirus (SARS-CoV) like virus in animals at a live animal market of Guanzhou in 2004 before and after culling of wild animal action taken by the local authority, in order to predict the re-emerging of SARS from animal originals in this region.

METHODSAnimals at live animal market were sampled for rectal and throat swabs in triplicate. A single step realtime reverse transcription-polymerase chain reaction (RT-PCR) diagnostic kit was performed for screening SARS-CoV like virus, the manual nested RT- PCR and DNA sequencing were performed for confirmation. Only specimens which tested positive for both of the N and P genes by nested RT-PCR were scored as positive.

RESULTSIn 31 animals sampled in January 5 2004 before culling of wild animals at Guangdong Province, including 20 cats (Felis catus), 5 red fox (Vulpes vulpes) and 6 Lesser rice field rats (Rattus losea), 8 (25.8%) animals were tested positive for SARS-CoV like virus by RT-PCR methods, of which 4 cats, 3 red fox and one Lesser rice field rats were included. However, two weeks after culling of animals and disinfection of the market were implemented, in 119 animals sampled in January 20 2004, including 6 rabbits (Oryctolagus cuniculus), 13 cats, 46 red jungle fowl (Gallus gallus), 13 spotbill duck (Anas platyrhynchos), 10 greylag goose (Anser anser), 31 Chinese francolin (Franclinus pintadeanus), only rectal swab from one greylag goose was tested positive for SARS-CoV like virus. Furthermore, in 102 animals that including 14 greylag gooses, 3 cats, 5 rabbits, 9 spotbill duck (Anaspoecilorhyncha), 2 Chinese francolin (Franclinus pintadeanus), 8 common pheasant (Phasianus colchicus), 6 pigeons, 9 Chinese muntjac (Muntiacus reevesi), 19 wild boar (Sus scrofa), 16 Lesser rice field rats, 5 dogs, 1 mink (Mustela vison), 3 goats, 2 green peafowl (Pavo muticus) sampled in April, May, June, July, August and November, only rectal swab from one pig was tested positive. However, of 12 and 10 palm civets sampled in November and December including five of which had been at the live animals market for 2 days, none of them was tested positive.

CONCLUSIONThis findings revealed that animals being sampled in April, May, June, July, August and November of 2004, only one rectal swab from a pig was tested positive as SARS-CoV like virus, much lower than the results from the previous year, suggesting that the possibility of re-emerging of human infection from animal origins is low for the winter of 2004-2005.

Animals ; Animals, Wild ; virology ; China ; DNA, Viral ; analysis ; Felidae ; virology ; Reverse Transcriptase Polymerase Chain Reaction ; SARS Virus ; isolation & purification

To characterize the prevalence and species/genotypes of Cryptosporidium spp. in farmed pigs in the north of the Yangtze River in Anhui Province.A total of 500 samples of pig feces were obtained from seven largescale pig farms in the north of the Yangtze River in Anhui Province. PCR and sequences analysis of the small subunit rDNA gene were used to detect and identify the Cryptosporidium species/genotypes.The overall prevalence of Cryptosporidium was 4.8% (24/500). Additionally, Cryptosporidium prevalence was 40.0% in Qianshan and 6.3% in Chuzhou, respectively. No Cryptosporidium infection was found in other sampling areas. The DNA sequence analysis of the SSUrDNA gene revealed that all of the isolates represented C. scrofarum. The Cryptosporidium infection rate (9.1%) of pigs (> 60 days) was significantly higher than the rates of both pigs (< 30 days) and pigs (30–60 days) (both P < 0.01).C. scrofarum in the farmed pigs in the north of the Yangtze River in Anhui Province may be a source of Cryptosporidium infection and pose a potential public health threat to humans and other animals, and therefore, the status should be paid more attention to.