What are the consequences of the disappearing human microbiota?
ABSTRACT Humans and our ancestors have evolved since the most ancient times with a commensal microbiota. The conservation of indicator species in a niche-specific manner across all of the studied human population groups suggests that the microbiota confer conserved benefits on humans. Nevertheless, certain of these organisms have pathogenic properties and, through medical practices and lifestyle changes, their prevalence in human populations is changing, often to an extreme degree. In this Essay, we propose that the disappearance of these ancestral indigenous organisms, which are intimately involved in human physiology, is not entirely beneficial and has consequences that might include post-modern conditions such as obesity and asthma.
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ABSTRACT: Plants and animals each have evolved specialized organs dedicated to nutrient acquisition, and these harbor specific bacterial communities that extend the host's metabolic repertoire. Similar forces driving microbial community establishment in the gut and plant roots include diet/soil-type, host genotype, and immune system as well as microbe-microbe interactions. Here we show that there is no overlap of abundant bacterial taxa between the microbiotas of the mammalian gut and plant roots, whereas taxa overlap does exist between fish gut and plant root communities. A comparison of root and gut microbiota composition in multiple host species belonging to the same evolutionary lineage reveals host phylogenetic signals in both eukaryotic kingdoms. The reasons underlying striking differences in microbiota composition in independently evolved, yet functionally related, organs in plants and animals remain unclear but might include differences in start inoculum and niche-specific factors such as oxygen levels, temperature, pH, and organic carbon availability. Copyright © 2015 Elsevier Inc. All rights reserved.Cell host & microbe 05/2015; 17(5):603-616. DOI:10.1016/j.chom.2015.04.009 · 12.19 Impact Factor
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ABSTRACT: The microbial communities that reside in the human gut (microbiota) and their impact on human health and disease are nowadays one of the most exciting new areas of research. A well-balanced microbial intestinal colonization in early postnatal life is necessary for the development of appropriate innate and adaptive immune responses and to establish immune homeostasis later in life. Although the composition and functional characteristics of a 'healthy' gut microbiota remain to be elucidated, perturbations in the microbial colonization of an infant's gastrointestinal tract have been associated with an increased risk of short- and long-term immunologically mediated diseases. Emerging evidence suggests that gut microbiota biomodulators, such as probiotics, prebiotics and synbiotics, may support disease prevention in infants who tend to have a delayed and/or aberrant initial colonization with reduced microbiota diversity (delivery by caesarean section, premature delivery, and excessive use of perinatal antibiotics). Under these dysbiosis conditions probiotics could act as 'surrogate' colonizers to prevent immune-mediated diseases. This review focuses on the influence of delivery mode on the colonization of the infant gastro-intestinal tract. In particular, it examines the manipulation of the gut microbiota composition through the use of gut microbiota biomodulators, in the management of aberrant initial gut colonization and subsequent consequences for the health of the offspring. Copyright © 2015 Elsevier B.V. All rights reserved.Clinica Chimica Acta 02/2015; DOI:10.1016/j.cca.2015.01.022 · 2.76 Impact Factor
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ABSTRACT: We investigated the effects of early colonizing bacteria on the colonic epithelium. We isolated dominant bacteria, Escherichia coli, Enterococcus faecalis, Lactobacillus intestinalis, Clostridium innocuum and a novel Fusobacterium spp., from the intestinal contents of conventional suckling rats and transferred them in different combinations into germfree (GF) adult rats. Animals were investigated after various times up to 21 days. Proliferative cell markers (Ki67, proliferating cell nuclear antigen, phospho-histone H3, cyclin A) were higher in rats monocolonized with E. coli than in GF at all time points, but not in rats monocolonized with E. faecalis. The mucin content of goblet cells declined shortly after E. coli administration whereas the mucus layer doubled in thickness. Fluorescence in situ hybridization analyses revealed that E. coli resides in this mucus layer. The epithelial mucin content progressively returned to baseline, following an increase in KLF4 and in the cell cycle arrest-related proteins p21(CIP1) and p27(KIP1). Markers of colonic differentiated cells involved in electrolyte (carbonic anhydrase II and slc26A3) and water (aquaglyceroporin3 (aqp3)) transport, and secretory responses to carbachol were modulated after E. coli inoculation suggesting that ion transport dynamics were also affected. The colonic responses to simplified microbiotas differed substantially according to whether or not E. coli was combined with the other four bacteria. Thus, proliferation markers increased substantially when E. coli was in the mix, but very much less when it was absent. This work demonstrates that a pioneer strain of E. coli elicits sequential epithelial remodeling affecting the structure, mucus layer and ionic movements and suggests this can result in a microbiota-compliant state.The ISME Journal advance online publication, 11 July 2014; doi:10.1038/ismej.2014.111.The ISME Journal 07/2014; DOI:10.1038/ismej.2014.111 · 9.27 Impact Factor