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Keywords:

  • adhesion;
  • adhesion-associated proteins;
  • Lactobacillus;
  • mucin;
  • mucus

Abstract

Aims:  To identify and characterize adhesion-associated proteins in the potential probiotic Lactobacillus fermentum BCS87.

Methods and Results:  Protein suspensions obtained from the treatment of Lact. fermentum BCS87 with 1 mol 1−1 LiCl were analysed by Western blotting using HRP-labelled porcine mucus and mucin. Two adhesion-associated proteins with relative molecular weight of 29 and 32 kDa were identified. The N-terminal and internal peptides of the 32 kDa protein (32-Mmubp) were sequenced, and the corresponding gene (32-mmub) was found by inverse polymerase chain reaction. The complete nucleotide sequence of 32-mmub revealed an open reading frame of 903 bp encoding a primary protein of 300 amino acids and a mature protein of 272 residues. A basic local alignment search showed 47–99% identity to solute-binding components of ATP binding cassette transporter proteins in Lactobacillus, Streptococcus and Clostridium. An OpuAC-conserved domain was identified and phylogenetic relationship analysis confirmed that 32-Mmubp belongs to the OpuAC family.

Conclusions:  Adhesion of Lact. fermentum BCS87 appeared to be mediated by two surface-associated proteins. 32-Mmubp is a component of ABC transporter system that also functions as an adhesin.

Significance and Impact of the Study:  Characterization of 32-Mmubp and 32-mmub will contribute to understanding the host–bacteria interactions of Lact. fermentum with the intestinal tract of pigs.