Objective To investigate the amino acid patterns in penicillin-binding protein 2(PBP2)in Neisseria gonorrhoeae isolates with reduced susceptibility to ceftriaxonc.and the relationship between the amino acid patterns and reduced ceftriaxone susceptibility.Methods DNA was extracted from 13 clinical isolates of N.gonorrhoeae.including 11 strains with decreased susceptibility to ceftriaxone and 2 sensitive isolates.The full-length penA gene encoding the penicillin-binding protein 2 was amplified and sequenced.BLASTn and BLASTx programs were used to assess the insertion and substitution patterns of nucleotides in penA gene and of amino acids in PBP2,respectively.Results BLASTn analysis revealed insertion or substitution of 18-38 nucleotides in the penA gene of gonococcal isolates with reduced ceftriaxone susceptibility.As shown by BLASTX analysis.there were five patterns of amino acid substitution or insertion in PBP2 of the 11 isolates with reduced ceftriaxone susceptibility.However.mosaic structure of PBP2 was not found in any of these isolates.Conclusion Mosaic PBP2 seems not to be the major factor contributing to the decrease in susceptibility of N.gonorrhoeae to ceftriaxone.

OBJECTIVEThis study was conducted to investigate the function of the first intron of porcine growth hormone (pGH) gene in the gene expression.

METHODSPCR method was used to amplify the first intron from pig genomic DNA. The intron was then inserted into pGH cDNA to construct pGH cDNA-intron (pGH cDNA-in). The recombinant adenoviruses containing pGH cDNA and pGH cDNA-in genes under control of CMV promoter were generated by homologous recombination method in HEK 293 cells respectively. The effect of the first intron on gene expression was evaluated by comparing the expression levels of pGH cDNA-in and pGH cDNA mediated by adenovirus vectors in CHO cells.

RESULTSThe expression level of pGH cDNA containing the first intron increased by 117%, which was significantly higher than that of pGH cDNA without the intron (P < 0.001).

CONCLUSIONThe first intron of pGH gene has the function to improve pGH gene expression.

Adenoviridae ; genetics ; Animals ; CHO Cells ; Cricetinae ; DNA Transposable Elements ; DNA, Complementary ; DNA, Recombinant ; Genetic Vectors ; Growth Hormone ; genetics ; Introns ; Swine