Analysis of Host-Inducing Proteome Changes in Bifidobacterium longum NCC2705 Grown in Vivo

Abstract

To investigate the molecular mechanisms underlying the adaptation of Bifidobacterium longum to the intestinal tract, we utilized a new model for rabbit intestinal culture of B. longum and reported the changes in proteomic profiles after incubation in the in vivo environment. By 2D-PAGE coupled with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and/or electrospray ionization tandem mass spectrometry (ESI-MS/MS) analyses, proteomic profiles of B. longum strain NCC2705 grown in the in vivo and in vitro environments were compared. Confirmed by semiquantitative RT-PCR, which exhibited at least a 3-fold change or greater, 19 up-regulated proteins, 14 down-regulated proteins, and 4 proteins with mobility changes were identified during intestinal growth. These identified proteins include key stress proteins, metabolism-related proteins, and proteins related to translation. Our results indicate that some useful proteins are expressed at higher levels in cells during intestinal growth. These proteins reflected the adaptation of B. longum NCC2705 to the intestine, such as EF-Tu which contributes to the retention or attachment as a Bifidobacterium adhesin-like factor, bile salt hydrolase (BSH) which might play an important role in the molecular mechanisms for the initial interaction of probiotic with the intestinal environment, and stress proteins which defend B. longum against the action of bile salts and other harmful ingredients of the gastrointestinal tract (GIT). The most striking fact of our observation was that four proteins GlnA1, PurC, LuxS, and Pgk exhibit clear post-translational modification. Western blot (WB) analysis and Pro-Q Diamond staining revealed that substances of the GIT trigger Pgk and LuxS phosphorylation at Ser/Thr residues for bacteria grown in vivo. These proteins were identified for the first time as bifidobacterial phosphoproteins. Our data suggest that the phosphorylated autoinducer-2 production protein LuxS of B. longum NCC2705 (LuxS-P) is the active form of LuxS and that LuxS-P may play a key role in the regulation of quorum sensing.

Allelic Variation of Bile Salt Hydrolase Genes in Lactobacillus salivarius Does Not Determine Bile Resistance Levels

“…Exposure of L. salivarius cells to bile or cholate did not induce the expression of bsh1. Genes for Bsh were also not induced by bile in L. acidophilus (45), contrasting with induction of bsh expression in L. plantarum WCFS1 by bile (7) and in B. longum NCC2705 by simulated intestinal stress conditions (63). It remains possible that L. salivarius bsh1 expression is inducible in vivo, modulated by factors other than bile.…”

Impact of the Metabolic Activity of Streptococcus thermophilus on the Colon Epithelium of Gnotobiotic Rats

“…For example, EF-Tu is an elongation factor playing a key role in protein synthesis but also in the maintenance in the GIT. The up-regulation of EF-Tu was observed in vivo for L. lactis (41) and Bifidobacterium (42) and in vitro for L. plantarum (43). Although S. thermophilus reduced most of its translation and protein synthesis machinery, EF-Tu was the sole protein belonging to protein synthesis pathway that was increased at a high level in digestive tract compared with milk (induction factor 12).…”

The cell-envelope proteome of Bifidobacterium longum in an in vitro bile environment

“…The study of the cytoplasmic proteome of B. longum under different gastrointestinal conditions (pH and bile) in vitro (Sánchez et al, 2005(Sánchez et al, , 2007 and in vivo (Yuan et al, 2008) was accomplished in previous studies. Also, the most abundant proteins secreted by this species were identified (Sánchez et al, 2008).…”