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Project description:Background: Based on 32 Escherichia coli and Shigella genome sequences, we have developed an E. coli pan-genome microarray. Publicly available genomes were annotated in a consistent manor to define all currently known genes potentially present in the species. The chip design was evaluated by hybridization of DNA from two sequenced E. coli strains, K-12 MG1655 (a commensal) and O157:H7 EDL933 (an enterotoxigenic E. coli). A dual channel and single channel analysis approach was compared for the comparative genomic hybridization experiments. Moreover, the microarray was used to characterize four unsequenced probiotic E. coli strains, currently marketed for beneficial effects on the human gut flora. Results: Based on the genomes included in this study, we were able to group together 2,041 genes that were present in all 32 genomes. Furthermore, we predict that the size of the E. coli core genome will approach ~1,560 essential genes, considerably less than previous estimates. Although any individual E. coli genome contains between 4,000 and 5,000 genes, we identified more than twice as many (11,872) distinct gene groups in the total gene pool (“pan-genome”) examined for microarray design. Benchmarking of the design based on sequenced control strain samples demonstrated a high sensitivity and relatively low false positive rate. Moreover, the array was highly sufficient to investigate the gene content of apathogenic isolates, despite the strong bias towards pathogenic E. coli strains that have been sequenced so far. Our analysis of four probiotic E. coli strains demonstrate that they share a gene pool very similar to the E. coli K-12 strains but also show significant similarity with enteropathogenic strains. Nonetheless, virulence genes were largely absent. Strain-specific genes found in probiotic E. coli but absent in E. coli K12 were most frequently phage-related genes, transposases and other genes related to mobile DNA, and metabolic enzymes or factors that may offer colonization fitness, which together with their asymptomatic nature may explain their nature. Conclusion: This high-density microarray provides an excellent tool for characterizing either DNA content or gene expression from unknown E. coli strains. Keywords: Comparative genomic hybridizations
2008-01-22 | GSE8595 | GEO
Project description:We have characterized three strains belonging to L. delbrueckii subspecies (bulgaricus, B; lactis, L; L.delbrueckii 23, M) highlighting their divergent origin, different galactose metabolic capabilities and we have demonstrated potential probiotic features.
2017-06-29 | PXD006551 | Pride
Project description:Obesity is a chronic, complex and multifactorial disease that has reached pandemia levels and is becoming a serious health problem. Intestinal microbiota is considered a main factor that affects body weight and fat mass, which points toward a critical role in the development of obesity. In this sense, probiotic bacteria might modulate the intestinal microbiota and the mucosal-associated lymphoid tissue. The aim of this study was to investigate the effects of L. paracasei, L. rhamnosus and B. breve feeding on the intestinal mucosa gene expression in a genetic animal model of obesity. We used microarrays to investigate the global gene expression on intestinal mucosa after the treatment with probiotic strains.
2016-12-25 | GSE73848 | GEO
Project description:A lactobacilli dominated microbiota in most pre and post-menopausal women is an indicator of vaginal health. A Nugent scoring system serves as a proxy for determining the ratio of lactobacilli to other vaginal inhabitants where a high score usually represents a diseased state, whilst an intermediate score represents a warning zone. The objective of this double blinded, placebo-controlled crossover study was to evaluate in 14 post-menopausal women with an intermediate score, the effect of vaginal administration of probiotic L. rhamnosus GR-1 and L. reuteri RC-14 on the microbiota and host response. The probiotic treatment did not result in changes to clinical parameters such as dryness, irritation and comfort, compared to when placebo was applied. Analysis using 16S rRNA sequencing and metabolomics profiling revealed that the proportional abundance of Lactobacillus was increased following probiotic administration as compared to placebo, which was weakly associated with an increase in lactate levels. Analysis of host responses by microarray showed the probiotics had an immune-modulatory response and multiplex cytokine analysis showed up-regulation of IL-5. This is the first study to use an interactomic approach for the study of vaginal probiotic administration in post-menopausal women. It shows that in some cases multifaceted approaches are required to detect the subtle trigger molecular changes induced by the host to instillation of probiotic strains.
2014-07-20 | GSE54363 | GEO