1,721,145 research outputs found
Probiogenomics as a tool to obtain genetic insights into adaptation of probiotic bacteria to the human gut.
No full textBifidobacteria and lactobacilli are widely exploited as healthpromoting
bacteria in many functional foods. However, the
molecular mechanisms as to how these bacteria positively
impact on host health are far from completely understood. For
this reason these microorganisms represent a growing area of
interest with respect to their genomics, molecular biology and
genetics. Recent genome sequencing of a large number of
strains of bifidobacteria and lactobacilli has allowed access
to the complete genetic makeup of representative members
of these bacteria. Here, we will discuss how the analysis of
genomic data has helped us to understand the mechanisms
by which these bacteria adapt to the specific environment
of the gastrointestinal tract, while also revealing genetic
functions that mediate specific host-microbe interactions
Bifidobacteria: from ecology to genomics
No full textBifidobacteria are high G+C Gram positive bacteria belonging to the phylum Actinobacteria. In recent years bifidobacteria have attracted a lot of attention because of their perceived positive contribution to the functionality of the human gastro intestinal tract. For this reason, scientific research on these bacteria has been rapidly expanding, in particular in areas such as genomics, molecular ecology and genetics. Ecological studies together with genome-based sequencing efforts have provided scientific evidence for the considerable contribution of bifidobacteria to the human gut microbiome. Furthermore, bifidobacterial genomics has revealed various genetic adaptations of these bacteria to the gastrointestinal nich
Insights into endogenous Bifidobacterium species in the human gut microbiota during adulthood
No full textBifidobacteria are among the earliest and most abundant bacterial colonizers of the neonatal gut in many mammals, where they elicit purported host health benefits. While early life-associated dynamics and diversity, as well as the metabolic and beneficial activities, of Bifidobacterium species have been well studied, functional contributions of bifidobacteria to health and well-being of adults remain less explored. In this opinion piece, we discuss the current knowledge regarding the relevance of endogenous Bifidobacterium species associated with adulthood. We identify knowledge gaps and discuss opportunities for microbiota enrichment with rationally selected strains of Bifidobacterium more adapted to the adult host. We propose that current knowledge and future studies in this area will help us to better understand the ecological, metabolic, and functional roles played by Bifidobacterium in the gut ecosystem across various host ages
Editorial: Bifidobacteria and Their Role in the Human Gut Microbiota
No full textThe human intestine is home of an almost inconceivable large number of microorganisms. The human gut microbiota can therefore be pictured as an organ placed within a host organism. The human gut microbiome, which in total may contain >100 times the number of genes present in our genome, endows us with functional features that we did not have to evolve ourselves. It is recognized that intestinal microbiota plays an important role in human health and disease. In fact, gut bacteria other than metabolize dietary components, may play complex roles such as modulation of the immune system and in reduction of gut infections. Variations in the presence and/or abundance of certain components of the intestinal microbiota have repeatedly been observed in patients that suffer from atopic diseases, inflammatory bowel disease, Crohn disease, ulcerative colitis, infectious colitis, colon cancer and diabetes. In this context, bifidobacteria represent one of the most common bacterial members of the human gut microbiota. Bifidobacteria are anaerobic, Gram-positive, irregular or branched rod-shaped bacteria that are commonly found in the gastro-intestinal tracts (GIT) of humans, especially during the first stages of life and most animal and insects. Bifidobacterial fluctuations seem directly associated with health effects and for these reasons they are being exploited as health-promoting or probiotic bacteria. However, despite the extensive commercial exploitation of bifidobacteria as probiotic bacteria, little is known about their impact or dependency on other members of the human gut microbiota or on their host. Genome analyses have highlighted the existence of gene repertoires encoding products that are responsible for the adaptation of bifidobacteria to the human intestine and intense research efforts at international level are ongoing to understand the molecular details of these interactions. Specifically, the molecular interactions that are presumed to exist between bifidobacteria and the human host, as well as interactions between different residents of intestinal microbiota are the main topic of bifidobacterial research communities
Role of sortase-dependent pili of Bifidobacterium bifidum PRL2010 in modulating bacterium-host interactions
No full textTurroni, Francesca et al.Bifidobacteria represent one of the dominant groups of microorganisms colonizing the human infant intestine. Commensal bacteria that interact with a eukaryotic host are believed to express adhesive molecules on their cell surface that bind to specific host cell receptors or soluble macromolecules. Whole-genome transcription profiling of Bifidobacterium bifidum PRL2010, a strain isolated from infant stool, revealed a small number of commonly expressed extracellular proteins, among which were genes that specify sortase-dependent pili. Expression of the coding sequences of these B. bifidum PRL2010 appendages in nonpiliated Lactococcus lactis enhanced adherence to human enterocytes through extracellular matrix protein and bacterial aggregation. Furthermore, such piliated L. lactis cells evoked a higher TNF-α response during murine colonization compared with their nonpiliated parent, suggesting that bifidobacterial sortase-dependent pili not only contribute to adherence but also display immunomodulatory activity.This work was supported in part by Fondazione Cariplo Grant 2010-0678 (to S.G. and V.T.); Irish Research Council for Science, Engineering, and Technology Embark postdoctoral Fellowship (to F.T.); and by PhD Fellowship Spinner 2013, Regione Emilia Romagna (to S.D.) and a Heath Research Board grant (to M.O.M.). D.v.S., M.O.M., and F.T. are members of The Alimentary Pharmabiotic Centre; D.v.S. is also a member of the Alimentary Glycoscience Research Cluster, both funded by Science Foundation Ireland through the Irish Government’s National Development Plan (Grant numbers 07/CE/B1368 and 08/SRC/B1393, respectively). M.O.M. is the recipient of a Health Research Board postdoctoral Fellowship Grant PDTM/20011/9.Peer Reviewe
Genome analysis of Bifidobacterium bifidum PRL2010 reveals metabolic pathways for host-derived glycan foraging
No full textTurroni, Francesca et al.The human intestine is densely populated by a microbial consortium whose metabolic activities are influenced by, among others, bifidobacteria. However, the genetic basis of adaptation of bifidobacteria to the human gut is poorly understood. Analysis of the 2,214,650-bp genome of Bifidobacterium bifidum PRL2010, a strain isolated from infant stool, revealed a nutrient-acquisition strategy that targets host-derived glycans, such as those present in mucin. Proteome and transcriptome profiling revealed a set of chromosomal loci responsible for mucin metabolism that appear to be under common transcriptional control and with predicted functions that allow degradation of various O-linked glycans in mucin. Conservation of the latter gene clusters in various B. bifidum strains supports the notion that host-derived glycan catabolism is an important colonization factor for B. bifidum with concomitant impact on intestinal microbiota ecology.This work was supported by National Institutes of Health–National Institute of Child Health and Human Development Grant 1R01HD061923 (to D.M.). D.v.S., A.Z., and F.B. are members of the Alimentary Pharmabiotic Centre, a Center for Science and Technology funded by Science Foundation Ireland, through the Irish Government’s National Development Plan Grant 07/CE/B1368.Peer Reviewe
Genomics and ecological overview of the genus Bifidobacterium
No full textMembers of the genus Bifidobacterium are high G + C Gram positive bacteria belonging to the phylum Actinobacteria, and represent common inhabitants of the gastro-intestinal tract (GIT) of mammals, birds and certain cold-blooded animals. The overall microbial population that resides in the GIT, referred to as the “gut microbiota”, is an extremely complex community of microorganisms whose functions are believed to have a significant impact on human physiology. Different ecological relationships between bifidobacteria and their host can be developed, ranging from opportunistic pathogenic interactions (e.g. in the case of Bifidobacterium dentium) to a commensal or even health-promoting relationship (e.g. in the case of Bifidobacterium bifidum and Bifidobacterium breve species). Among the known health-promoting or probiotic microorganisms, bifidobacteria represent one of the most dominant group and some bifidobacterial species are frequently used as the probiotic ingredient in many functional foods. However, despite the generally accepted importance of bifidobacteria as constituents of the human microbiota, there is only limited information available on their phylogeny, physiology and genetics. Moreover, host–microbiota interactions and cross-talk between different members of the gut microbiota are far from completely understood although they represent a crucial factor in the development and maintenance of human physiology and immune system. The aim of this review is to highlight the genetic and functional features of bifidobacteria residing in the human GIT using genomic and ecology-based information
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