construction and characterization of a streptococcus suis serotype 2 recombinant expressing enhanced green fluorescent protein建设和表征的链球菌血清型2重组表达增强绿色荧光蛋白.pdfVIP

Construction and Characterization of a Streptococcus suis Serotype 2 Recombinant Expressing Enhanced Green Fluorescent Protein Tao Chen, Qin Huang, Zhaolong Li, Wei Zhang, Chengping Lu, Huochun Yao* Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China Abstract Streptococcus suis serotype 2 (S. suis 2) is an important pathogen, responsible for diverse diseases in swine and humans. To obtain a S. suis 2 strain that can be tracked in vitro and in vivo, we constructed the Egfp-HA9801 recombinant S. suis 2 strain with egfp and spcr genes inserted via homologous recombination. To assess the effects of the egfp and spcr genes in HA9801, the biochemical characteristics, growth features and virulence in Balb/C mice were compared between the recombinant and the parent HA9801 strain. We detected the EGFP expression from Egfp-HA9801 by epifluorescence microscopy. The results showed that the biochemical characterization and growth features of the Egfp-HA9801 recombinant were highly similar to that of the parent HA9801. We did not find significant differences in lethality (50% lethal dose), morbidity and mortality between the two strains. Furthermore, the bacterial counts in each various tissues of Egfp- HA9801-infected mice displayed similar dynamic compared with the HA9801-infected mice. Our results also showed that the Egfp-HA9801 cells grown at 37uC for 36 h displayed greater green fluorescence signals than the cells grown at 28uC for 36 h and 37uC for 24 h. The fluorescence in the tissue cryosections of Egfp-HA9801-injected mice was also stronger than that of the HA9801 group. Together, these results indicate that the egfp and spcr insertions into the Egfp-HA9801 recombinant d