scholarly journals Endospores and other lysis-resistant bacteria comprise a widely shared core community within the human microbiota

2017 ◽  
Author(s):  
Sean M. Kearney ◽  
Sean M. Gibbons ◽  
Mathilde Poyet ◽  
Thomas Gurry ◽  
Kevin Bullock ◽  
...  

AbstractEndospore-formers in the human microbiota are well adapted for host-to-host transmission, and an emerging consensus points to their role in determining health and disease states in the gut. The human gut, more than any other environment, encourages the maintenance of endospore formation, with recent culture-based work suggesting that over 50% of genera in the microbiome carry genes attributed to this trait. However, there has been limited work on the ecological role of endospores and other stress-resistant cellular states in the human gut. In fact, there is no data to indicate whether organisms with the genetic potential to form endospores actually form endosporesin situand how sporulation varies across individuals and over time. Here, we applied a culture-independent protocol to enrich for endospores and other stress-resistant cells in human feces to identify variation in these states across people and within an individual over time. We see that cells with resistant states are more likely than those without to be shared among multiple individuals, which suggests that these resistant states are particularly adapted for cross-host dissemination. Furthermore, we use untargeted fecal metabolomics in 24 individuals and within a person over time to show that these organisms respond to shared environmental signals, and in particular, dietary fatty acids, that likely mediate colonization of recently disturbed human guts.

Author(s):  
Eleanor M. Townsend ◽  
Lucy Kelly ◽  
George Muscatt ◽  
Joshua D. Box ◽  
Nicole Hargraves ◽  
...  

The investigation of the microbial populations of the human body, known as the microbiome, has led to a revolutionary field of science, and understanding of its impacts on human development and health. The majority of microbiome research to date has focussed on bacteria and other kingdoms of life, such as fungi. Trailing behind these is the interrogation of the gut viruses, specifically the phageome. Bacteriophages, viruses that infect bacterial hosts, are known to dictate the dynamics and diversity of bacterial populations in a number of ecosystems. However, the phageome of the human gut, while of apparent importance, remains an area of many unknowns. In this paper we discuss the role of bacteriophages within the human gut microbiome. We examine the methods used to study bacteriophage populations, how this evolved over time and what we now understand about the phageome. We review the phageome development in infancy, and factors that may influence phage populations in adult life. The role and action of the phageome is then discussed at both a biological-level, and in the broader context of human health and disease.


2018 ◽  
Vol 43 (11) ◽  
pp. 1122-1130 ◽  
Author(s):  
Baraa K. Al-Khazraji ◽  
J. Kevin Shoemaker

The autonomic nervous system elicits continuous beat-by-beat homeostatic adjustments to cardiovascular control. These modifications are mediated by sensory inputs (e.g., baroreceptors, metaboreceptors, pulmonary, thermoreceptors, and chemoreceptors afferents), integration at the brainstem control centres (i.e., medulla), and efferent autonomic neural outputs (e.g., spinal, preganglionic, and postganglionic pathways). However, extensive electrical stimulation and functional imaging research show that the brain’s higher cortical regions (e.g., insular cortex, medial prefrontal cortex, anterior cingulate cortex) partake in homeostatic regulation of the cardiovascular system at rest and during exercise. We now appreciate that these cortical areas form a network, namely the “cortical autonomic network” (CAN), which operate as part of a larger central autonomic network comprising 2-way communication of cortical and subcortical areas to exert autonomic influence. Interestingly, differential patterns of CAN activity and ensuing cardiovascular control are present in disease states, thereby highlighting the importance of considering the role of CAN as an integral aspect of cardiovascular regulation in health and disease. This review discusses current knowledge on human cortical autonomic activation during volitional exercise, and the role of exercise training on this activation in both health and disease.


2021 ◽  
Author(s):  
Saeed Shoaie ◽  
Sunjae Lee ◽  
Mathieu Almeida ◽  
Gholamreza Bidkhori ◽  
Nicolas Pons ◽  
...  

Abstract The role of gut microbiota in humans is of great interest, and metagenomics provided the possibilities for extensively analysing bacterial diversity in health and disease. Here we explored the human gut microbiome samples across 19 countries, performing compositional, functional and integrative analysis. To complement these data and analyse the stability of the microbiome, we followed 86 healthy Swedish individuals over one year, with four sampling times and extensive clinical phenotyping. The integrative analysis of temporal microbiome changes shows the existence of two types of species with a tendency to vary in abundance with time, here called outflow and inflow species. Importantly, the former tends to be enriched in disease, while the latter is enriched in health. We suggest that the decrease of disease-associated outflow and the increase of health-associated inflow species with time may be a fundamental albeit previously unrecognized aspect of the homeostasis maintenance in a healthy microbiome.


2021 ◽  
pp. 101-112
Author(s):  
Nazar Reehana ◽  
Mohamed Yousuff Mohamed Imran ◽  
Nooruddin Thajuddin ◽  
D. Dhanasekaran

2014 ◽  
Vol 27 (1) ◽  
pp. 94-106 ◽  
Author(s):  
Emma L. Beckett ◽  
Zoe Yates ◽  
Martin Veysey ◽  
Konsta Duesing ◽  
Mark Lucock

A growing number of studies in recent years have highlighted the importance of molecular nutrition as a potential determinant of health and disease. In particular, the ability of micronutrients to regulate the final expression of gene products via modulation of transcription and translation is now being recognised. Modulation of microRNA (miRNA) by nutrients is one pathway by which nutrition may mediate gene expression. miRNA, a class of non-coding RNA, can directly regulate gene expression post-transcriptionally. In addition, miRNA are able to indirectly influence gene expression potential at the transcriptional level via modulation of the function of components of the epigenetic machinery (DNA methylation and histone modifications). These mechanisms interact to form a complex, bi-directional regulatory circuit modulating gene expression. Disease-specific miRNA profiles have been identified in multiple disease states, including those with known dietary risk factors. Therefore, the role that nutritional components, in particular, vitamins and minerals, play in the modulation of miRNA profiles, and consequently health and disease, is increasingly being investigated, and as such is a timely subject for review. The recently posited potential for viable exogenous miRNA to enter human blood circulation from food sources adds another interesting dimension to the potential for dietary miRNA to contribute to gene modulation.


mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
L. Caetano M. Antunes ◽  
Julie A. K. McDonald ◽  
Kathleen Schroeter ◽  
Christian Carlucci ◽  
Rosana B. R. Ferreira ◽  
...  

ABSTRACTThe mammalian gut contains a complex assembly of commensal microbes termed microbiota. Although much has been learned about the role of these microbes in health, the mechanisms underlying these functions are ill defined. We have recently shown that the mammalian gut contains thousands of small molecules, most of which are currently unidentified. Therefore, we hypothesized that these molecules function as chemical cues used by hosts and microbes during their interactions in health and disease. Thus, a search was initiated to identify molecules produced by the microbiota that are sensed by pathogens. We found that a secreted molecule produced by clostridia acts as a strong repressor ofSalmonellavirulence, obliterating expression of theSalmonellapathogenicity island 1 as well as host cell invasion. It has been known for decades that the microbiota protects its hosts from invading pathogens, and these data suggest that chemical sensing may be involved in this phenomenon. Further investigations should reveal the exact biological role of this molecule as well as its therapeutic potential.IMPORTANCEMicrobes can communicate through the production and sensing of small molecules. Within the complex ecosystem formed by commensal microbes living in and on the human body, it is likely that these molecular messages are used extensively during the interactions between different microbial species as well as with host cells. Deciphering such a molecular dialect will be fundamental to our understanding of host-microbe interactions in health and disease and may prove useful for the design of new therapeutic strategies that target these mechanisms of communication.


2000 ◽  
Vol 13 (2) ◽  
pp. 229-254 ◽  
Author(s):  
Toni Steer ◽  
Hollie Carpenter ◽  
Kieran Tuohy ◽  
Glenn R. Gibson

AbstractOne of the most topical areas of human nutrition is the role of the gut in health and disease. Specifically, this involves interactions between the resident microbiota and dietary ingredients that support their activities. Currently, it is accepted that the gut microflora contains pathogenic, benign and beneficial components. Some microbially induced disease states such as acute gastroenteritis and pseudomembranous colitis have a defined aetiological agent(s). Speculation on the role of microbiota components in disorders such as irritable bowel syndrome, bowel cancer, neonatal necrotising enterocolitis and ulcerative colitis are less well defined, but many studies are convincing. It is evident that the gut microflora composition can be altered through diet. Because of their perceived health-promoting status, bifidobacteria and lactobacilli are the commonest targets. Probiotics involve the use of live micro-organisms in food; prebiotics are carbohydrates selectively metabolized by desirable moieties of the indigenous flora; synbiotics combine the two approaches. Dietary intervention of the human gut microbiota is feasible and has been proven as efficacious in volunteer trials. The health bonuses of such approaches offer the potential to manage many gut disorders prophylactically. However, it is imperative that the best methodologies available are applied to this area of nutritional sciences. This will undoubtedly involve a genomic application to the research and is already under way through molecular tracking of microbiota changes to diet in controlled human trials.


2016 ◽  
Vol 113 (33) ◽  
pp. E4801-E4809 ◽  
Author(s):  
Kendrick H. Yim ◽  
Thomas L. Prince ◽  
Shiwei Qu ◽  
Fang Bai ◽  
Patricia A. Jennings ◽  
...  

Because of their importance in maintaining protein homeostasis, molecular chaperones, including heat-shock protein 90 (Hsp90), represent attractive drug targets. Although a number of Hsp90 inhibitors are in preclinical/clinical development, none strongly differentiate between constitutively expressed Hsp90β and stress-induced Hsp90α, the two cytosolic paralogs of this molecular chaperone. Thus, the importance of inhibiting one or the other paralog in different disease states remains unknown. We show that the natural product, gambogic acid (GBA), binds selectively to a site in the middle domain of Hsp90β, identifying GBA as an Hsp90β-specific Hsp90 inhibitor. Furthermore, using computational and medicinal chemistry, we identified a GBA analog, referred to as DAP-19, which binds potently and selectively to Hsp90β. Because of its unprecedented selectivity for Hsp90β among all Hsp90 paralogs, GBA thus provides a new chemical tool to study the unique biological role of this abundantly expressed molecular chaperone in health and disease.


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