ABSTRACT
To investigated the toxin genes distribution and molecular characteristics of Vibrio parahaemolyticus from pa‐tients in Ningbo ,V .parahaemolyticus strains were collected from patients with food poisoning and diarrhea .Thermostable di‐rect hemolysin gene (tdh) and TDH‐related hemolysin gene (trh) were detected by polymerase chain reaction (PCR) .Molecu‐lar characteristics were acquired by multi‐locus sequence typing (MLST ) .Of 248 clinical strains were isolated from 2006 to 2012 .Forty‐eight strains were selected to detect virulence genes and MLST genotyping .Forty‐two isolates were detected as tdh+ and 11 isolates were detected as trh+ .There were 9 STs and one undifferentiated type in Ningbo clinical strains .Thirty‐two strains were classified into ST3 ,5 strains into ST265 and 3 strains into ST120 .ST265 was found in Ningbo strains com‐pared with strains from other regions of China .Strains with tdh+ accounted for the majority in Ningbo clinical strains .Twen‐ty‐five strains of ST3 clone were tdh+ /trh‐.There were 9 STs coexsited in Ningbo clinical strains .ST3 clone was dominant , followed by ST265 and ST120 .Strains with tdh+ /trh‐were dominant in the ST3 clone .The unique ST262 was found in Ning‐bo clinical strains .
ABSTRACT
Summary: A prokaryotic expression recombinant plasmid pET-PIB to express porin B (PIB) of Neisseria gonorrhoeae in E.coli DE3 was constructed in order to provide a basis of research in detection, prophylactic and therapeutic vaccine against the pathogen infection. The gene encoding PIB was amplified by PCR from Neisseria gonorrhoeae and cloned into prokaryotic expression plasmid pET-28a(+) to construct a pET-PIB recombinant, which was verified by restriction endonuclease and DNA sequencing. Protein PIB was expressed in E.coli DE3 induced with IPTG. The antigenicity of the expressed protein was evaluated by indirect ELISA. Rabbits were immunized with the protein and serum was collected after immunization. To assess the immunogenicity of the protein, the titer of serum to protein PIB was determined by ELISA. DNA sequence analysis showed that the nucleic acid sequence of PIB gene was 99.28 % of homology compared with that (NGPIB18) published in GenBank. A 41 kD fused protein was detected by SDS-PAGE and was proven to have reactivity with anti-PIB polyclonal antibody from mouse. A polyclonal antibody to PIB of 1:4000 titer determined by indirect ELISA was obtained from rabbit immunized with the purified product. Recombinant plasmid encoding PIB of Neisseria gonorrhoeae was constructed. Protein PIB with antigenicity and immunogenicity was successfully expressed.
ABSTRACT
In order to provide a rational research basis for clinical detection and genetic engineering vaccine, plasmid pET-28a (+) encoding both Porin gene PIA and PIB of Neisseria gonorrhoeae was constructed and a fusion protein in E. coli DE3 expressed. The fragments of PIA and PIB gene of Neisseria gonorrhoeae were amplified and cloned into prokaryotic expression plasmid pET-28a (+) with double restriction endonuclease cut to construct recombinant pET-PIB-PIA. The recombinant was verified with restriction endonuclease and sequenced and transformed into E. coli DE3 to express the fusion protein PIB-PIA after induced with IPTG. The results showed PIA-PIB fusion DNA fragment was proved correct through sequencing. A 67 kD (1 kD= 0.992 1 ku) fusion protein had been detected by SDS-PAGE. It was concluded that the fusion protein was successively expressed.