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PMID:22006318

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Citation

Andersen, JM, Barrangou, R, Abou Hachem, M, Lahtinen, S, Goh, YJ, Svensson, B and Klaenhammer, TR (2011) Transcriptional and functional analysis of galactooligosaccharide uptake by lacS in Lactobacillus acidophilus. Proc. Natl. Acad. Sci. U.S.A. 108:17785-90

Abstract

Probiotic microbes rely on their ability to survive in the gastrointestinal tract, adhere to mucosal surfaces, and metabolize available energy sources from dietary compounds, including prebiotics. Genome sequencing projects have proposed models for understanding prebiotic catabolism, but mechanisms remain to be elucidated for many prebiotic substrates. Although β-galactooligosaccharides (GOS) are documented prebiotic compounds, little is known about their utilization by lactobacilli. This study aimed to identify genetic loci in Lactobacillus acidophilus NCFM responsible for the transport and catabolism of GOS. Whole-genome oligonucleotide microarrays were used to survey the differential global transcriptome during logarithmic growth of L. acidophilus NCFM using GOS or glucose as a sole source of carbohydrate. Within the 16.6-kbp gal-lac gene cluster, lacS, a galactoside-pentose-hexuronide permease-encoding gene, was up-regulated 5.1-fold in the presence of GOS. In addition, two β-galactosidases, LacA and LacLM, and enzymes in the Leloir pathway were also encoded by genes within this locus and up-regulated by GOS stimulation. Generation of a lacS-deficient mutant enabled phenotypic confirmation of the functional LacS permease not only for the utilization of lactose and GOS but also lactitol, suggesting a prominent role of LacS in the metabolism of a broad range of prebiotic β-galactosides, known to selectively modulate the beneficial gut microbiota.

Links

PubMed PMC3203779 Online version:10.1073/pnas.1114152108

Keywords

DNA, Complementary/genetics; Gene Expression Regulation, Bacterial/physiology; Lactobacillus acidophilus/genetics; Lactobacillus acidophilus/metabolism; Membrane Transport Proteins/metabolism; Microarray Analysis; Oligonucleotide Array Sequence Analysis; Oligosaccharides/pharmacokinetics; Prebiotics; Reverse Transcriptase Polymerase Chain Reaction; beta-Galactosidase/genetics; beta-Galactosidase/metabolism

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status


See also

References

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