Project description:Numerous studies have shown that resistance to oxidative stress is crucial to stay healthy and to reduce the adverse effects of aging. Accordingly, nutritional interventions using antioxidant food-grade compounds or food products are currently an interesting option to help improve health and quality of life in the elderly. Live lactic acid bacteria (LAB) administered in food, such as probiotics, may be good antioxidant candidates. Nevertheless, information about LAB-induced oxidative stress protection is scarce. To identify and characterize new potential antioxidant probiotic strains, we have developed a new functional screening method using the nematode Caenorhabditis elegans as host. C. elegans were fed on different LAB strains (78 in total) and nematode viability was assessed after oxidative stress (3mM and 5mM H2O2). One strain, identified as Lactobacillus rhamnosus CNCM I-3690, protected worms by increasing their viability by 30% and, also, increased average worm lifespan by 20%. We performed a transcriptomic analysis of C. elegans fed with this strain and showed that increased lifespan is correlated with differential expression of the DAF-16/insulin-like pathway, which is highly conserved in humans. Gene expression in C. elegans wild-type strain (N2) was analyzed in worm populations fed with E. coli OP50 (control condition) or the corresponding LAB (Lactobacillus rhamnosus CNCM I-3690 or Lactobacillus rhamnosus CNCM I-4317) . Three days and ten days feeding period was analyzed.
Project description:The presence of tagatose in Lactobacillus rhamnosus strain GG caused induction of a large number of genes associated with carbohydrate metabolism including the phosphotransferase system. In addition, these results indicate the tagatose enhanced the growth of Lactobacillus casei 01 and Lactobacillus rhamnosus strain GG and their probiotic activities by activating tagatose-associated PTS networks. Two-condition experiment, Lactobacillus rhamnosus GG with glucose vs. Lactobacillus rhamnosus GG with tagatose. For preparing the total RNA, Lactobacillus rhamnosus GG cells were grown at 37M-BM-0C in prebiotic minimum medium supplemented with 2% glucose or tagatose for 24 h.
Project description:The bacterium Lactobacillus rhamnosus antagonizes the fungus Candida albicans. The transcriptional response of C. albicans to the presence of L. rhamnosus in an in vitro infection model with and without antibiotic treatment was investigated using microarrays.
Project description:The present study reports comparative surfacomics (study of cell-surface exposed proteins) of the probiotic Lactobacillus rhamnosus strain GG and the dairy strain Lc705.
Project description:Transcriptional profiling of probiotic Lactobacillus rhamnosus strain GG mid-exponential pH-controlled bioreactor cultures before and after exposure to bovine bile (0.2% ox gall). Keywords: bile, stress response Cell samples from four biological replicates were harvested right before (time point 0 min) and 10, 30 and 120 min after bile treatment. Each sample was compared to a common reference sample (time point 0 min, mid-exponential growth phase Lactobacillus rhamnosus GG cultures). A total of 12 hybridizations were performed using balanced dye-swap design. Dyes were balanced between compared sample pairs and between biological replicates.
Project description:The presence of tagatose in Lactobacillus rhamnosus strain GG caused induction of a large number of genes associated with carbohydrate metabolism including the phosphotransferase system. In addition, these results indicate the tagatose enhanced the growth of Lactobacillus casei 01 and Lactobacillus rhamnosus strain GG and their probiotic activities by activating tagatose-associated PTS networks.
Project description:Transcriptional profiling of probiotic Lactobacillus rhamnosus strain GG mid-exponential pH-controlled bioreactor cultures before and after exposure to bovine bile (0.2% ox gall). Keywords: bile, stress response
Project description:Transcriptional profiling of probiotic Lactobacillus rhamnosus GG during growth in industrial-type whey medium in pH-controlled bioreactor cultures at two different growth pH: 4.8 and 5.8. Keywords: growth phase, growth pH
