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 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. 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 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: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 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
Project description:Lactobacillus rhamnosus GG has become one of the most widely marketed and studied probiotic strains. Several genes important for probiotic function have been identified, including the spaCBA-srtC1 gene cluster encoding pili, which have been shown to be important for certain of its probiotic properties. The spaCBA-srtC1 gene cluster has been reported to be unstable in L. rhamnosus GG isolated from liquid dairy products and therefore the present study examined the L. rhamnosus GG genome stability throughout an industrial production process from the original deposit to the freeze-dried products including intermediate fermentations and single colony isolates prepared from these samples. The results showed that the original deposit was identical to the reference ATCC and that the genome sequence stayed fully intact throughout the production process. No SNPs or larger genomic changes occurred in any of the samples throughout the production process and the spaCBA-srtC1 gene locus was fully conserved and intact in all 31 samples examined. In addition, phenotypic expression of pili was demonstrated using immune-gold labelling EM. The images showed that pili production was preserved throughout the production process and that the number of pili were consistent in all batches. The present study extends the scope of previous findings to an industrial setting and shows that the region around the spaCBA-srtC1 cluster exhibits high stability in L. rhamnosus GG in an industrial production process.
Project description:Analysis of human primary macrophages after live Lactobacillus rhamnosus GG (LGG) or LC705 stimulation for 6h and 24h. The results reveal novel mechanisms for probiotics-induced activation of the healthy human innate immune system. Macrophages are phagocytic cells of the innate immune system that perform sentinel functions to initiate appropriate responses to surrounding stimuli. Macrophages that reside at mucosa encounter ingested bacteria. Our understanding of the responses elicited by nonpathogenic bacteria in human innate immune system is limited. Lactobacillus are nonpathogenic bacteria commonly used in food and as supplements with health-promoting probiotic potential. In this study, we have utilized global gene expression profiling to compare the responses of human primary macrophages to two closely related, well-characterized L. rhamnosus strains LGG and LC705. Our results demonstrate that live LGG and LC705 induced quantitatively different gene expression in macrophages. A gene ontology analysis revealed functional similarities and differences in responses to LGG and LC705. Both LGG and LC705 induced IL-1b production in macrophages that required caspase-1 activity. LC705 but not LGG induced a strong type I IFN-dependent gene activation that correlated with the ability of LC705 to prevent influenza A virus replication and production of viral proteins in macrophages. Differentiated 7d human primary macrophages from 18 healthy individuals were stimulated with either live L. rhamnosus GG (LGG) or LC705 for 6 h and 24 h in RPMI medium containing penicillin and streptomycin. As a control, macrophages were stimulated with the medium only. The experiment was performed three times, each time with cells from six different individuals (samples 1-3). For each experiment, macrophages were stimulated separately as described, and macrophages from different donors were pooled after each stimulation experiment. Extracted RNA was hybridized to AffymetrixM-BM-. U133-plus2.0 GeneChipM-BM-. arrays.