ABSTRACT
In the present study, 89 porcine reproductive and respiratory syndrome virus (PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2 (Nsp2) and glycoprotein 5 (GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007-2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates-HH08, DY, and YN-2011-were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.
ABSTRACT
Objective To investigate the effect of different concenrtrations of basic fibroblast growth factor (bFGF) on proliferation of human dental pulp cell in vitro,and to find out the most effective concentration of bFGF. Methods Dental pulp cells were isolated from dental pulp tissue explants.The pulp cells were divided into 5 groups randomly,bFGF was added into each group until the ultimately concentrations were 0.1,1.0,10.0 and 100.0 ?g?L-1respectively while the group without bFGF as control group. The effects of bFGF on dental pulp cells were assayed by absorbency A and relative growth rate(RGR) with MTT colorimetric method. Results bFGF at concentrations of 1.0-100.0 ?g?L-1 promoted the cell proliferation (P0.05). Conclusion bFGF has the capability of promoting the proliferation of human dental pulp cells,and the smallest effective concentration is 1.0 ?g?L-1,the most strong cell proliferation takes place at bFGF concentration of 10.0 ?g?L-1.
ABSTRACT
Objective:To clone and characterize the 16S rRNA of six species in the bacteria infecting respiratory tract to make gene chip.Methods:The primers of the target gene were designed and synthesized,and then the aimed fragment of the 16s rRNA was amplified by PCR and cloned.Finally the recombinant plasmids were characterized.Results:(1)The 16s rRNA gene of six species of bacteria was amplified.It was found that the size of amplified product by PCR was 1 300 bp in E.coli,S.aureus,S.pneumoniae,K.pneumoniae and H.influenzae and that of 1 100 bp in P.aeruginosa.(2)The JM109 transferred by the recombinant plasmid pMD18-T grew in Ampr culture was white colonies.(3)The specific bands could be found by restriction endonuclease and PCR analysis. (4)The sequence of the six bacterial 16s rRNA showed the same as those in the GenBank.Conclusion:The 16s rRNA of six species of bacteria is successfully amplified and cloned into plasmid pMD18-T. It will provide the basis for making gene chip detecting the six species of bacteria infecting respiratory tract.
ABSTRACT
Objective:To construct an eukaryotic expressing vector pCR3 1 15 containing CP15 gene of Crypstosporidium parvum(C.parvum) and express it in Hela cells Methods:CP15 gene of C parvum was obtained from pMD18 T 15 disgested by BglⅡ and was inserted into eukaryotic expressing vector pCR3 1(+) in BamHⅠ site,and then Hela cells were transfected with recombinant by liposomes The transcription and expressed products of CP15 in the transfected Hela cells were assayed by RT PCR,ELISA and indiret immunofluorescence assay after screening with G418 Results:It showed that pCR3 1 15 was constructed successfully CP15 gene was transcripted in transfectants and CP15 protein with obvious biological activity was highly expressed in Hela cells Conclusion:CP15 gene in recombinant vector is proved to be expressed in Hela cells and obvious biological activity of expression production in transfected cells was detected