What are the consequences of the disappearing 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.
- SourceAvailable from: Priscila Chaverri
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- "Similar improvement in host fitness has been reported for insects, in which endosymbiotic species of Burkholderia are acquired horizontally every generation (Kikuchi et al., 2007). Even in humans it has been shown that the disappearance of ancestral indigenous commensal microbiota, which is intimately involved in human physiology, is not beneficial and may have many health consequences (Sears, 2005; Blaser and Falkow, 2009). Protective mutualism conferred by horizontally transmitted microbes has been poorly studied in plants (except for mycorrhizal or rhizobial associations), especially in their native environments (Evans et al., 2003; Berlec, 2012). "
ABSTRACT: It has been shown that the disappearance of, or drastic changes in, ancestral and indigenous (or native) endosymbiotic microbiota can lead to many adverse health consequences. However, the effects of changes in beneficial endosymbionts in plants are poorly known (except for mycorrhizal and rhizobial associations). We sampled and compared endophytes from hundreds of trees belonging to the economically important genus Hevea, the source of natural rubber, in their native range in the Amazon basin and in plantations. We also conducted antagonism tests to determine the potential effects that some of these endophytes may have on selected plant pathogenic fungi. The natural and indigenous endosymbiotic mycota of the rubber tree (Hevea) contains a high diversity of beneficial fungi that may protect against pathogens (protective mutualism). In contrast, plantation trees have a reduced and different diversity of these beneficial fungi. We propose that abundance, and not just presence, of competitive fungal strains and species (i.e., Trichoderma and Tolypocladium) create a protective effect against pathogens in wild trees. This study provides support for the importance of mutualistic endosymbionts in plant health and ecosystem resilience, and calls for awareness of their potential loss by human-related activities.Fungal Ecology 10/2015; 17. DOI:10.1016/j.funeco.2015.04.001 · 2.93 Impact Factor
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- "Co-habitation in humans leads to sharing of microbiota, which is enhanced when dogs also co-habit in the same house (Song et al., 2013). Ironically, hygiene measures aimed at reducing pathogen transmission may have had broad negative impacts on the transmission of commensals and may underlie the loss of diversity observed in the West (Blaser and Falkow, 2009). Who Are They? "
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 · 12.33 Impact Factor
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- "Since the first exposure to microorganisms seems to be crucial to establish immune homeostasis, delay in exposure to bacterial colonizers and, in turn, the lack of a regulatory mechanism may be involved and may even be more relevant than infections (the 'microbiota hypothesis'). This 'new' hygiene hypothesis starts with the assumption that altered gut microbial communities, closely associated with the loss of ancient and coevolved microbes ( " old friends " ) lead to the disruption of the gut immune homeostasis . In 1986, Tim Mosmann and Bob Coffman identified two subsets of activated T helper lymphocytes which differed from each other in their pattern of cytokine production and their functions: those that made interferon (IFN)-γ as their signature cytokine (Th1 cells) and those that produced IL-4 (Th2 cells). "
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 · 2.82 Impact Factor