Application of the shsp gene, encoding a small heat shock protein, as a food-grade selection marker for lactic acid bacteria.

ABSTRACT: Plasmid pSt04 of Streptococcus thermophilus contains a gene encoding a protein with homology to small heat shock proteins (A. Geis, H. A. M. El Demerdash, and K. J. Heller, Plasmid 50:53-69, 2003). Strains cured from the shsp plasmids showed significantly reduced heat and acid resistance and a lower maximal growth temperature. Transformation of the cloned shsp gene into S. thermophilus St11 lacking a plasmid encoding shsp resulted in increased resistance to incubation at 60 degrees C or pH 3.5 and in the ability to grow at 52 degrees C. A food-grade cloning system for S. thermophilus, based on the plasmid-encoded shsp gene as a selection marker, was developed. This approach allowed selection after transfer of native and recombinant shsp plasmids into different S. thermophilus and Lactococc

SUBMITTER: El Demerdash HA 

PROVIDER: S-EPMC169115 | biostudies-literature | 2003 Aug

REPOSITORIES: biostudies-literature