Proteomic analysis of global changes in protein expression during bile salt exposure of Bifidobacterium longum NCIMB 8809.
Adaptation to and tolerance of bile stress are among the main limiting factors to ensure survival of bifidobacteria in the intestinal environment of humans. The effect of bile salts on protein expression patterns of Bifidobacterium longum was examined. Protein pattern comparison of strains grown with or without bile extract allowed us to identify 34 different proteins whose expression was regulated. The majority of these proteins were induced after both a minor (0.6 g liter(-1)) and a major (1.2 g liter(-1)) exposure to bile. These include general stress response chaperones, proteins involved in transcription and translation and in the metabolism of amino acids and nucleotides, and several enzymes of glycolysis and pyruvate catabolism. Remarkably, xylulose 5-phosphate/fructose 6-phosphate phosphoketolase, the key enzyme of the so-called bifidobacterial shunt, was found to be upregulated, and the activity on fructose 6-phosphate was significantly higher for protein extracts of cells grown in the presence of bile. Changes in the levels of metabolic end products (acetate and lactate) were also detected. These results suggest that bile salts, to which bifidobacteria are naturally exposed, induce a complex physiological response rather than a single event in which proteins from many different functional categories take part. This study has extended our understanding of the molecular mechanism underlying the capacity of intestinal bifidobacteria to tolerate bile.
Sánchez
Borja
B
Unité Flore Lactique et Environnement Carné, INRA, Domaine de Vilvert, 78350 Jouy-en-Josas, France.
Champomier-Vergès
Marie-Christine
MC
Anglade
Patricia
P
Baraige
Fabienne
F
de Los Reyes-Gavilán
Clara G
CG
Margolles
Abelardo
A
Zagorec
Monique
M
D000446:Aldehyde-Lyases / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D001644:Bifidobacterium / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004734:Energy Metabolism / Q000502:physiology; D005636:Fructosephosphates / Q000378:metabolism; D006801:Humans; D007422:Intestines / Q000382:microbiology; D018832:Molecular Chaperones / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology; D040901:Proteomics; D014158:Transcription, Genetic / Q000502:physiology
D000596:Amino Acids; D001426:Bacterial Proteins; D001647:Bile Acids and Salts; D005636:Fructosephosphates; D018832:Molecular Chaperones; D009711:Nucleotides; C027618:fructose-6-phosphate; D000446:Aldehyde-Lyases; C022367:phosphoketolase