Identification ofLactobacillus plantarumGenes That Are Induced in the Gastrointestinal Tract of Mice

Abstract

Lactobacillus plantarum is a flexible and versatile microorganism that inhabits a variety of environmental niches, including the human gastrointestinal (GI) tract. Moreover, this lactic acid bacterium can survive passage through the human or mouse stomach in an active form. To investigate the genetic background of this persistence, resolvase-based in vivo expression technology (R-IVET) was performed in L. plantarum WCFS1 by using the mouse GI tract as a model system. This approach identified 72 L. plantarum genes whose expression was induced during passage through the GI tract as compared to laboratory media. Nine of these genes encode sugar-related functions, including ribose, cellobiose, sucrose, and sorbitol transporter genes. Another nine genes encode functions involved in acquisition and synthesis of amino acids, nucleotides, cofactors, and vitamins, indicating their limited availability in the GI tract. Four genes involved in stress-related functions were identified, reflecting the harsh conditions that L. plantarum encounters in the GI tract. The four extracellular protein encoding genes identified could potentially be involved in interaction with host specific factors. The rest of the genes are part of several functionally unrelated pathways or encode (conserved) hypothetical proteins. Remarkably, a large number of the functions or pathways identified here have previously been identified in pathogens as being important in vivo during infection, strongly suggesting that survival rather than virulence is the explanation for the importance of these genes during host residence.Traditionally, lactic acid bacteria (LAB) are applied extensively in the production of a wide variety of fermented food and feed products. In addition, certain LAB species, in particular from the genus Lactobacillus, are natural inhabitants of the gastrointestinal (GI) tract and may have probiotic effects in humans and animals (2). Moreover, LAB have great potential to serve as delivery vehicles of health-promoting or therapeutic compounds to the human GI tract (20,48). Among the different species encompassed by this genus, Lactobacillus plantarum is encountered in many environmental niches, including some dairy, meat, and a variety of vegetable fermentations (28). Because of the long tradition of utilization of L. plantarum in industrial and artisanal fermentations, this microbe is generally regarded as safe. In addition to the occurrence of L. plantarum in our diets, this microbe is frequently encountered as a natural inhabitant of the human GI tract (2). The complete 3.3-Mbp genome sequence of L. plantarum WCFS1 has been determined (28). This strain is a single-colony isolate of strain NCIMB8826, which effectively survives passage of the human stomach in an active form, reaches the ileum in high numbers compared to other strains, and is detectable in the colon (51). Intriguingly, genome sequence comparison revealed that the closest relatives of L. plantarum include Listeria innocua and L. monocytogenes, which also naturally inhabit ...

Functional genomics of Lactobacillus casei establishment in the gut

“…As it was done for pathogens, it is essential to develop the cellular microbiology of symbionts and particularly to identify the genes required for their establishment and persistence in the gut. Transcriptomic profiling identified up-regulated genes linked to metabolic functions, stress responses, and pili synthesis during early colonization (11)(12)(13). Comparative genomics among Lactobacilli identified strain-specific candidate genes for extended colonization: In Lactobacillus rhamnosus, persistence was attributed to an spaCBA locus encoding LPXTG-like pilins (14), and in Lactobacillus johnsonii it was attributed to specific glycosyltransferases, a phosphotransfer system, and a protease (15).…”

Differential NF-κB pathways induction by Lactobacillus plantarum in the duodenum of healthy humans correlating with immune tolerance

“…Several studies have addressed its adaptive responses to the mammalian gastrointestinal tract (17)(18)(19). To current knowledge, L. plantarum is perceived via Toll-like receptor (TLR)2-4, CD14 antigen, and nucleotide-binding oligomerization domain-containing 2 (NOD2) (20)(21)(22).…”

Genes involved in obesity: Adipocytes, brain and microflora

“…participated to the identification of genes of Lactobacillus plantarum whose expression was induced during passage of these bacteria through the gastrointestinal tract. Interestingly, 9 of these 72 genes encode sugar-related functions, whereas others are involved in acquisition and synthesis of amino acids, nucleotides, cofactors and vitamins (Bron, 2004).…”