Increase of stress resistance in Lactococcus lactis via a novel food-grade vector expressing a shsp gene from Streptococcus thermophilus
Braz. j. microbiol
;
43(3): 1157-1164, July-Sept. 2012. ilus, graf, tab
Article
in English
| LILACS
| ID: lil-656686
ABSTRACT
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.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Drug Resistance
/
Gene Expression
/
Erythromycin
/
Streptococcus thermophilus
/
Food Microbiology
/
Lactobacillus
Limits:
Humans
Language:
English
Journal:
Braz. j. microbiol
Journal subject:
Microbiology
Year:
2012
Type:
Article
Affiliation country:
China
Institution/Affiliation country:
Agricultural University of Hebei/CN
/
China Agricultural University/CN
/
Institute of Microbiology/CN
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