Increase of stress resistance in Lactococcus lactis via a novel food-grade vector expressing a shsp gene from Streptococcus thermophilus
AUTOR(ES)
Tian, Hongtao, Tan, Jianxin, Zhang, Lifang, Gu, Xinxi, Xu, Wentao, Guo, Xinghua, Luo, Yunbo
FONTE
Braz. J. Microbiol.
DATA DE PUBLICAÇÃO
2012-09
RESUMO
The effects of the expression of a small heat shock protein (shsp) gene from Streptococcus thermophilus on stress resistance in Lactococcus lactis under different environmental stresses were investigated in this study. pMG36e-shsp, an expression vector, was first constructed by inserting a shsp open reading frame (ORF) cloned from S. thermophilus strain St-QC into pMG36e. Then, a food-grade expression vector, pMG-shsp, was generated by deleting the erythromycin resistance gene from pMG36e-shsp. The transformation rate of pMG-shsp was comparable to that of pMG36e-shsp when each of these two vectors was introduced into L. lactis. These results demonstrated that the shsp ORF could successfully used as a food-grade selection marker in both pMG-shsp and pMG36e-shsp. Furthermore, the growth characteristics were almost the same between L. lactis ML23 transformants harboring pMG36e or pMG-shsp. The survival rate of L. lactis ML23 expressing the shsp ORF were increased to 0.032%, 0.006%, 0.0027%, 0.03%, and 0.16% under the following environmental stresses: heat, acid, ethanol, bile salt and H2O2, respectively. These results indicated that the expression of the shsp gene in the food-grade vector pMG-shsp conferred resistance to environmental stresses without affecting the growth characteristics of L. lactis ML23.
Documentos Relacionados
- Food-Grade Delivery System for Controlled Gene Expression in Lactococcus lactis
- Novel Food-Grade Plasmid Vector Based on Melibiose Fermentation for the Genetic Engineering of Lactococcus lactis
- Food-grade cloning and expression system for Lactococcus lactis.
- A Potential Food-Grade Cloning Vector for Streptococcus thermophilus That Uses Cadmium Resistance as the Selectable Marker
- A Food-Grade Cloning System for Industrial Strains of Lactococcus lactis