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Mol Cell Proteomics. 2014 Oct;13(10):2558-72. doi: 10.1074/mcp.M114.039156. Epub 2014 Jun 25.

Integrated transcriptomic and proteomic analysis of the bile stress response in a centenarian-originated probiotic Bifidobacterium longum BBMN68.

Author information

1
From the ‡Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Municipality, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China;
2
§Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland;
3
¶Core Genomic Facility, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
4
From the ‡Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Municipality, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China; haoyl@cau.edu.cn.

Abstract

Bifidobacteria are natural inhabitants of the human gastrointestinal tract and well known for their health-promoting effects. Tolerance to bile stress is crucial for bifidobacteria to survive in the colon and to exert their beneficial actions. In this work, RNA-Seq transcriptomic analysis complemented with proteomic analysis was used to investigate the cellular response to bile in Bifidobacterium longum BBMN68. The transcript levels of 236 genes were significantly changed (≥ threefold, p < 0.001) and 44 proteins were differentially abundant (≥1.6-fold, p < 0.01) in B. longum BBMN68 when exposed to 0.75 g l(-1) ox-bile. The hemolysin-like protein and bile efflux systems were significantly over produced, which might prevent bile adsorption and exclude bile, respectively. The cell membrane composition was modified probably by an increase of cyclopropane fatty acid and a decrease of transmembrane proteins, resulting in a cell membrane more impermeable to bile salts. Our hypothesis was later confirmed by surface hydrophobicity assay. The transcription of genes related to xylose utilization and bifid shunt were up-regulated, which increased the production of ATP and reducing equivalents to cope with bile-induced damages in a xylan-rich colon environment. Bile salts signal the B. longum BBMN68 to gut entrance and enhance the expression of esterase and sortase associated with adhesion and colonization in intestinal tract, which was supported by a fivefold increased adhesion ability to HT-29 cells by BBMN68 upon bile exposure. Notably, bacterial one-hybrid and EMSA assay revealed that the two-component system senX3-regX3 controlled the expression of pstS in bifidobacteria and the role of this target gene in bile resistance was further verified by heterologous expression in Lactococcus lactis. Taken altogether, this study established a model for global response mechanisms in B. longum to bile.

PMID:
24965555
PMCID:
PMC4188986
DOI:
10.1074/mcp.M114.039156
[Indexed for MEDLINE]
Free PMC Article
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