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Construction and characterization of a Streptococcus suis serotype 2 recombinant expressing enhanced green fluorescent protein.

Chen T, Huang Q, Li Z, Zhang W, Lu C, Yao H - PLoS ONE (2012)

Bottom Line: We did not find significant differences in lethality (50% lethal dose), morbidity and mortality between the two strains.Our results also showed that the Egfp-HA9801 cells grown at 37°C for 36 h displayed greater green fluorescence signals than the cells grown at 28°C for 36 h and 37°C for 24 h.Together, these results indicate that the egfp and spc(r) insertions into the Egfp-HA9801 recombinant did not significantly change the virulence when compared with HA980, and this EGFP labeled strain can be used for future S. suis 2 pathogenesis research.

View Article: PubMed Central - PubMed

Affiliation: 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 spc(r) genes inserted via homologous recombination. To assess the effects of the egfp and spc(r) 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 37°C for 36 h displayed greater green fluorescence signals than the cells grown at 28°C for 36 h and 37°C 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 spc(r) insertions into the Egfp-HA9801 recombinant did not significantly change the virulence when compared with HA980, and this EGFP labeled strain can be used for future S. suis 2 pathogenesis research.

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Bacterial distribution in different organs from mice infected i.p. with HA9801 parent and Egfp-HA9801 recombinant strains.Bacterial loads in the blood (A) are expressed as CFU/ml, and in the liver (B), spleen(C), lung (D), kidney (E) and brain (F) as CFU/0.05 g of tissue. Results are expressed as mean ± SEM of at least three infected mice per p.i. time point. No significant differences were found between the two strains throughout the experiment (P>0.05).
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pone-0039697-g004: Bacterial distribution in different organs from mice infected i.p. with HA9801 parent and Egfp-HA9801 recombinant strains.Bacterial loads in the blood (A) are expressed as CFU/ml, and in the liver (B), spleen(C), lung (D), kidney (E) and brain (F) as CFU/0.05 g of tissue. Results are expressed as mean ± SEM of at least three infected mice per p.i. time point. No significant differences were found between the two strains throughout the experiment (P>0.05).

Mentions: To further investigate the virulence of the Egfp-HA9801 recombinant, in vivo colonization experiments were carried out. According to the results of LD50 assessment, mice were IP inoculated with about 6.0×108 CFU in 1 ml THB of the recombinant or parental strains. The live bacteria were recovered from the lung, liver, kidney, spleen, brain and blood at each designated timepoint. As shown in Fig. 4, bacterial counts from each specific tissue of Egfp-HA9801-infected mice were not significantly different from that of the HA9801-infected mice (P>0.05). These results suggested that the colonization of Egfp-HA9801 had not been obviously influenced by inserting egfp and spcr gene into the S. suis 2 genome. Together with the above results, this shows that Egfp-HA9801 was very similar with HA9801 in terms of virulence, presentation of symptoms and infection process. Therefore, the recombinant strain can be used as an EGFP labeled strain for SS2 pathogenesis research under natural conditions.


Construction and characterization of a Streptococcus suis serotype 2 recombinant expressing enhanced green fluorescent protein.

Chen T, Huang Q, Li Z, Zhang W, Lu C, Yao H - PLoS ONE (2012)

Bacterial distribution in different organs from mice infected i.p. with HA9801 parent and Egfp-HA9801 recombinant strains.Bacterial loads in the blood (A) are expressed as CFU/ml, and in the liver (B), spleen(C), lung (D), kidney (E) and brain (F) as CFU/0.05 g of tissue. Results are expressed as mean ± SEM of at least three infected mice per p.i. time point. No significant differences were found between the two strains throughout the experiment (P>0.05).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3401235&req=5

pone-0039697-g004: Bacterial distribution in different organs from mice infected i.p. with HA9801 parent and Egfp-HA9801 recombinant strains.Bacterial loads in the blood (A) are expressed as CFU/ml, and in the liver (B), spleen(C), lung (D), kidney (E) and brain (F) as CFU/0.05 g of tissue. Results are expressed as mean ± SEM of at least three infected mice per p.i. time point. No significant differences were found between the two strains throughout the experiment (P>0.05).
Mentions: To further investigate the virulence of the Egfp-HA9801 recombinant, in vivo colonization experiments were carried out. According to the results of LD50 assessment, mice were IP inoculated with about 6.0×108 CFU in 1 ml THB of the recombinant or parental strains. The live bacteria were recovered from the lung, liver, kidney, spleen, brain and blood at each designated timepoint. As shown in Fig. 4, bacterial counts from each specific tissue of Egfp-HA9801-infected mice were not significantly different from that of the HA9801-infected mice (P>0.05). These results suggested that the colonization of Egfp-HA9801 had not been obviously influenced by inserting egfp and spcr gene into the S. suis 2 genome. Together with the above results, this shows that Egfp-HA9801 was very similar with HA9801 in terms of virulence, presentation of symptoms and infection process. Therefore, the recombinant strain can be used as an EGFP labeled strain for SS2 pathogenesis research under natural conditions.

Bottom Line: We did not find significant differences in lethality (50% lethal dose), morbidity and mortality between the two strains.Our results also showed that the Egfp-HA9801 cells grown at 37°C for 36 h displayed greater green fluorescence signals than the cells grown at 28°C for 36 h and 37°C for 24 h.Together, these results indicate that the egfp and spc(r) insertions into the Egfp-HA9801 recombinant did not significantly change the virulence when compared with HA980, and this EGFP labeled strain can be used for future S. suis 2 pathogenesis research.

View Article: PubMed Central - PubMed

Affiliation: 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 spc(r) genes inserted via homologous recombination. To assess the effects of the egfp and spc(r) 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 37°C for 36 h displayed greater green fluorescence signals than the cells grown at 28°C for 36 h and 37°C 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 spc(r) insertions into the Egfp-HA9801 recombinant did not significantly change the virulence when compared with HA980, and this EGFP labeled strain can be used for future S. suis 2 pathogenesis research.

Show MeSH
Related in: MedlinePlus