Comparative proteomic analysis of Lactobacillus plantarumfor the identification of key proteins in bile tolerance

Abstract

BackgroundLactic acid bacteria are commonly marketed as probiotics based on their putative or proven health-promoting effects. These effects are known to be strain specific but the underlying molecular mechanisms remain poorly understood. Therefore, unravelling the determinants behind probiotic features is of particular interest since it would help select strains that stand the best chance of success in clinical trials. Bile tolerance is one of the most crucial properties as it determines the ability of bacteria to survive in the small intestine, and consequently their capacity to play their functional role as probiotics. In this context, the objective of this study was to investigate the natural protein diversity within the Lactobacillus plantarum species with relation to bile tolerance, using comparative proteomics.ResultsBile tolerance properties of nine L. plantarum strains were studied in vitro. Three of them presenting different bile tolerance levels were selected for comparative proteomic analysis: L. plantarum 299 V (resistant), L. plantarum LC 804 (intermediate) and L. plantarum LC 56 (sensitive). Qualitative and quantitative differences in proteomes were analyzed using two-dimensional electrophoresis (2-DE), tryptic digestion, liquid chromatography-mass spectrometry analysis and database search for protein identification. Among the proteins correlated with differences in the 2-DE patterns of the bacterial strains, 15 have previously been reported to be involved in bile tolerance processes. The effect of a bile exposure on these patterns was investigated, which led to the identification of six proteins that may be key in the bile salt response and adaptation in L. plantarum: two glutathione reductases involved in protection against oxidative injury caused by bile salts, a cyclopropane-fatty-acyl-phospholipid synthase implicated in maintenance of cell envelope integrity, a bile salt hydrolase, an ABC transporter and a F0F1-ATP synthase which participate in the active removal of bile-related stress factors.ConclusionsThese results showed that comparative proteomic analysis can help understand the differential bacterial properties of lactobacilli. In the field of probiotic studies, characteristic proteomic profiles can be identified for individual properties that may serve as bacterial biomarkers for the preliminary selection of strains with the best probiotic potential.

Isolation, Identification and Screening of Potential Probiotic Bacteria in Milk from South African Saanen Goats

“…Although the bile concentration of the human gastrointestinal tract varies, the mean intestinal bile concentration is believed to be 0.3 %, and the staying time is suggested to be 4 hours (Prasad et al, 1998;Dunne et al, 2001). The ability of all the isolates to resist bile salts was revealed after 24 hours of incubation at high ox-gall concentrations is most likely due to the expression of bile-resistance related proteins in the bacterial cells (Hamon et al, 2011). Owing to the high tolerance of bile salt of all the isolates, we expect the strains to be effective in bile salt deconjugation and consequently effective in lowering serum cholesterol.…”

Comparative Genomics Reveals Biomarkers to Identify Lactobacillus Species

“…Use of Lactobacillus to control canine intestinal infections is an interesting proposal [13]. Lactobacillus is an economically important organism, especially as bioactive molecules, probiotic, preservative, fermentation and maturation of the sausages, milk products [14][15][16][17][18]. The dominance of Lactobacillus species such as L. iners, L. jensenii, L. gasseri, and L. crispatus in the vaginal region acts as a barrier for invasion of pathogenic bacteria and virus.…”

“…Lactobacillus plantarum was found to possess genes-mub, fbp and bsh, which encode for mucus-binding protein, fibronectin-binding protein and bile salt hydrolase, respectively. These genes were projected as probiotic identification markers [15]. Multiplex PCR using species-specific primers for amplifying recA gene of the L. plantarum group enabled identification of strains to be L. paraplantarum and L. pentosus [33].…”

Profiles and technological requirements of urogenital probiotics

“…If they will be applied as oral capsule or foods, their survival must be studied in intestinal fluid or into their components, either in one phase assays, or in continuous models resembling the different areas of the intestinal tract [220][221][222][223][224][225][226].. The strains must survive under these conditions and express later their beneficial characteristics [219][220][221][222][223][224][225][226].…”