Project description:Understanding how the human gut microbiota and host are impacted by probiotic bacterial strains requires carefully controlled studies in humans, and in mouse models of the gut ecosystem where potentially confounding variables that are difficult to control in humans can be constrained. Therefore, we characterized the fecal microbiomes and metatranscriptomes of adult female monozygotic twin pairs through repeated sampling 4 weeks prior to, 7 weeks during, and 4 weeks following consumption of a commercially-available fermented milk product (FMP) containing a consortium of Bifidobacterium animalis subsp. lactis, two strains of Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis subsp. cremoris, and Streptococcus thermophilus. In addition, gnotobiotic mice harboring a 15-species model human gut microbiota whose genomes contain 58,399 known or predicted protein-coding genes were studied prior to and after gavage with all five sequenced FMP strains. 140 samples total. Evaluation of changes in a model community's structure over time after exposure to a consortium of 5 fermented milk product (FMP) strains.
Project description:Introduction: Fermented milk products are part of the staple diet for many Mediterranean populations. Most of these traditional foods are enriched with lactobacilli and other lactic acid bacteria and metabolites resulting from lactose fermentation. There is currently very little scientific knowledge on the influence of diet supplementation with fermented milk on the gut microbiota metabolism and composition. Methods: We integrated 16S rRNA gene-based taxonomic profiling with metaproteomic-based functional analysis to investigate the gut microbiota modifications in rats exposed for 8 weeks to diet supplementation with casu axedu, a traditional fermented milk produced within rural communities in Sardinia (Italy). Results and Discussion: Several taxa showed a significantly increased abundance at the end of the dietary treatment, including Phascolarctobacterium, Prevotella, Blautia glucerasea, and Akkermansia muciniphila, while Bifidobacterium, Lachnoclostridium, Odoribacter, Bacteroides dorei and Dubosiella newyorkensis were decreased compared to the control rats. Metaproteomic analysis highlighted a striking reshape of the Prevotella proteome profile in agreement with its blooming in casu axedu-fed animals, suggesting an increase of the glycolytic activity through the Embden Meyerhof Parnas Pathway over the Entner Doudoroff Pathway. Moreover, an increased production of succinate was observed, which in turn significantly boosted the abundance of Phascolartcobacterium and its production of propionate. Fermented milk consumption was also associated with promotion of microbial synthesis of branched chain essential amino acids L-valine and L-leucine. Finally, metaproteomic data indicated a reduction of bacterial virulence factors and host inflammatory markers, suggesting that the consumption of casu axedu can have beneficial effects on the gut mucosa health.
Project description:Understanding how the human gut microbiota and host are impacted by probiotic bacterial strains requires carefully controlled studies in humans, and in mouse models of the gut ecosystem where potentially confounding variables that are difficult to control in humans can be constrained. Therefore, we characterized the fecal microbiomes and metatranscriptomes of adult female monozygotic twin pairs through repeated sampling 4 weeks prior to, 7 weeks during, and 4 weeks following consumption of a commercially-available fermented milk product (FMP) containing a consortium of Bifidobacterium animalis subsp. lactis, two strains of Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis subsp. cremoris, and Streptococcus thermophilus. In addition, gnotobiotic mice harboring a 15-species model human gut microbiota whose genomes contain 58,399 known or predicted protein-coding genes were studied prior to and after gavage with all five sequenced FMP strains. 73 samples total. Evaluation of changes in a model community's metatranscriptome over time after exposure to a consortium of 5 fermented milk product (FMP) strains (40 samples); evaluation of the gene expression of the FMP strains in other in vitro conditions, including MRS medium (B. animalis subsp. lactis only, 4 samples) and a commercial FMP fermentation (all 5 strains, 6 samples); evaluation of the gene expression of native human microbiomes before and after the consumption of a commercial FMP (23 samples).
Project description:The survival of probiotics could be strongly enhanced by delivery vehicles, but the mechanism was unknown. In this study, whole genome microarray technology was used to detect the gene expression profiles of probiotic Lactobacillus casei Zhang in the absence and presence of fermented milk in simulated gastrointestinal tract. The results showed the gene expression profiles were significantly different under these two different conditions. The change of the gene expression profile may be helpful to comprehend the role of delivery vehicles in enhancing the survival of probiotics. Twelve samples of bacterial cells in the absence and presence of fermented milk were collected at 3 h in simulated gastric juice, 4 h and 8 h in intestinal juice, 2 biological replicates were obtained in each time point. The average of the normalized expression values of the 2 biological replicates for each probe was regarded as the expression value of a predicted gene. To identify the expression pattern of each gene across different treatments, n-fold change ratios were calculated for every gene in pure L. casei Zhang versus L. casei Zhang in fermented milk.