A proteomic approach towards understanding the cross-talk between Bacteroides fragilis and Bifidobacterium longum in co-culture

A better understanding of the interactions among intestinal microbes is needed in order to decipher the complex cross-talk that takes place within the human gut. Bacteroides and Bifidobacterium genera are among the most relevant intestinal bacteria and it has been previously reported that co-culture of these two microorganisms affect their survival. Therefore, co-cultures of Bifidobacterium longum NB667 and Bacteriodes fragilis DSMZ2151 were performed with the aim of unravelling the mechanisms involved in their interaction. To this end we applied proteomic (2D-DIGE) analyses and quantified by chromatographic techniques the bacterial metabolites produced during co-incubation. Co-culture stimulated the growth of B. longum retarding that of B. fragilis, with concomitant changes in the production of some proteins and metabolites of both bacteria. The combined culture promoted up-regulation of the bifidobacterial pyruvate kinase and down-regulation of the Bacteroides phoshoenolpyruvate carboxykinase, two enzymes involved in the catabolism of carbohydrates. Moreover, B. fragilis FKBP-type peptidyl-prolyl cis/trans isomerase, a protein with chaperone-like activity, was found to be over-produced in co-culture, suggesting the induction of a stress response in this microorganism. This study provides mechanistic data to deepen our understanding on the interaction between Bacteroides and Bifidobacterium intestinal populations.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author