Comparison of expression vectors in Lactobacillus reuteri strains

Michela Lizier, Pier G. Sarra, Roberto Cauda, Franco Lucchini

Research output: Contribution to journalArticle

Abstract

The synthesis of heterologous proteins in lactobacilli is strongly influenced by the promoter selected for the expression. In addition, the activity of the promoters themselves may vary among different bacterial hosts. Three different promoters were investigated for their capability to drive enhanced green fluorescent protein (EGFP) expression in Lactococcus lactis spp. cremoris MG1363, in Lactobacillus reuteri DSM 20016T and in five L. reuteri strains isolated from chicken crops. The promoters of the Lactobacillus acidophilus surface layer protein gene (slp), L. acidophilus lactate dehydrogenase gene (ldhL) and enterococcal rRNA adenine N-6-methyltransferase gene (ermB) were fused to the coding sequence of EGFP and inserted into the backbone of the pTRKH3 shuttle vector (pTRKH3-slpGFP, pTRKH3-ldhGFP, pTRKH3-ermGFP). Besides conventional analytical methods, a new quick fluorimetric approach was set up to quantify the EGFP fluorescence in transformed clones using the Qubit fluorometer. ermB proved to be the most effective promoter in L. reuteri isolates, producing 3.90 × 10-7 g of fluorescent EGFP (mL ODstationary culture) -1. Under the same conditions, the ldhL promoter produced 2.66 × 10-7 g of fluorescent EGFP (mL OD stationary culture)-1. Even though the slp promoter was efficient in L. lactis spp. cremoris MG1363, it was nearly inactive both in L. reuteri DSM 20016T and in L. reuteri isolates.

Original languageEnglish
Pages (from-to)8-15
Number of pages8
JournalFEMS Microbiology Letters
Volume308
Issue number1
DOIs
Publication statusPublished - 2010

Keywords

  • Chicken crop
  • Constitutive promoter
  • ErmB
  • Green fluorescent protein
  • LdhL
  • Slp

ASJC Scopus subject areas

  • Microbiology
  • Genetics
  • Molecular Biology
  • Medicine(all)

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