The intestinal microbiota can be defined as a consortium of groups of bacteria.
From: Metabolomics and Microbiomics, 2016
Related terms:
Metabolic Pathway
Polysaccharide
Short-Chain Fatty Acid
Metabolite
Microflora
Electric Potential
Microbiome
Bifidobacterium
Mouse
Human Microbiome in Health and Disease - Part A
Gargi Bhattacharjee, ... Vijai Singh, in Progress in Molecular Biology and Translational Science, 2022
Abstract
Gut microbiota is a highly dense population of different kinds of bacteria residing in the gut which co-evolves with the host. It engages in a number of metabolic and immunological activities. Gut microbiota is associated with maintenance of health, and unbalanced microbiota contributes in the development of several diseases. Alteration of beneficial gut microbiota population triggers gastrointestinal diseases including irritable bowel syndrome, inflammatory bowel disease, celiac disease, colorectal cancer, and many others. Gut microbiota can be affected by multiple factors such as diet, stress, genetic variations. In this chapter, we highlight how gut microbiota plays a key role in pathogenesis of gastrointestinal disease.
Effect on the Host Metabolism
M.H. Sarafian, ... A. Hart, in The Microbiota in Gastrointestinal Pathophysiology, 2017
Abstract
The gut microbiota plays multiple key roles in host metabolism. Sustained interaction between gut microbiota and host is necessary to ensure healthy body functions. Studies have shown the implications of gut microbiota in lipid and energy metabolism via production of short chain fatty acids (SCFAs), phenolics, and other molecules. Gut microbiota dysbiosis initiates and exacerbates pathways related to SCFAs, and can induce disease development, such as Metabolic syndrome. This chapter provides comprehensive insights into physiological mechanisms affected by the gut microbiota. The use of state-of-the-art technologies, are important to provide a better understanding of human gut microbiota. Currently, the use of metagenomics and metabonomics are powerful approaches that contribute to that effort.
Diet-microbiome interactions and the regulation of the epigenome
Iara Cassandra V. Ibay, ... Kristina Martinez-Guryn, in Nutritional Epigenomics, 2019
1 Introduction
The gut microbiota has been implicated in the development of several life-altering diseases such as obesity, diabetes, inflammatory bowel disease, and cardiovascular diseases. However, the mechanisms that link gut microbiota composition and function to disease outcome are only beginning to be discovered. One such mechanism that may drive disease development in response to altered gut microbiota is epigenetic modification. The interaction between gut microbiota and epigenetics is further influenced by dietary-induced shifts in the gut microbiota. Collectively, these factors drive epigenetic programs that influence the development of disease. The goal of this chapter is to describe (1) the general characteristics of the gut microbiota, (2) the dietary impact on the gut microbiota, (3) the microbial impact on epigenetics, and (4) mechanisms underlying diet-microbe interactions on the host epigenome and consequences for host health.
Medicinal Natural Products: A Disease-Focused Approach
Aditya Arya, ... Satyajit D. Sarker, in Annual Reports in Medicinal Chemistry, 2020
2.2.2 Gut microbiota
The gut microbiota of an individual contains trillions of microorganisms that participate in various physiological functions, including vitamin production, maintenance of intestinal cells, development of the immune system and neutralization of pathogens, drugs and toxins.66 The gut microbiota also has an important role in extracting energy from food and could be involved in the development of obesity.67,68 In obese mice, the gut microbiota extracts more energy from food than in lean mice.69 In humans with obesity, treatment with vancomycin for 1 week modulates the gut microbiota and reduces insulin sensitivity, compared with baseline levels.70 Transfer of the gut microbiota from lean individuals to those with obesity improves insulin sensitivity in the recipients.71 These results suggest that modulation of the gut microbiota could have beneficial effects on obesity.
The Microbiome in Health and Disease
Yukuang Guo, ... Hyunyoung Jeong, in Progress in Molecular Biology and Translational Science, 2020
Abstract
Gut bacteria are predominant microorganisms in the gut microbiota and have been recognized to mediate a variety of biotransformations of xenobiotic compounds in the gut. This review is focused on one of the gut bacterial xenobiotic metabolisms, reduction. Xenobiotics undergo different types of reductive metabolisms depending on chemically distinct groups: azo (-N
N-), nitro (-NO2), alkene (-CC-), ketone (-CO), N-oxide (-N
O), and sulfoxide (-SO). In this review, we have provided select examples of drugs in six chemically distinct groups that are known or suspected to be subjected to the reduction by gut bacteria. For some drugs, responsible enzymes in specific gut bacteria have been identified and characterized, but for many drugs, only circumstantial evidence is available that indicates gut bacteria-mediated reductive metabolism. The physiological roles of even known gut bacterial enzymes have not been well defined.
MICROFLORA OF THE INTESTINE | The Natural Microflora of Humans
G.C. Yap, ... B.W. Lee, in Encyclopedia of Food Microbiology (Second Edition), 2014
Aging
The gut microbiota undergoes changes with the aging of the host. Eubacterium and Bacteroides declined whereas Ruminoccus, Clostridium perfringens, and Enterococci increased. There is an abundance of Bifidobacterium and Lactobacillus in the aging human gut microbiota; however, contrasting results were reported when comparing the abundance of Bifidobacterium and Lactobacillus to adult gut microbiota.
When the gut microbiota of young adults, elderly, and centenarians are compared, the fecal bacteria compositions of centenarians differ significantly, with fecal composition characterized by a higher abundance of Proteobacteria and Bacilli (Figure 1).
Figure 1. Progression of gut microbiota signatures from birth to elderly. Symbols (↑) and (↓) represent the increase and decrease of bacteria abundance, respectively, as compared with the previous age groups.
Summarized from Eckburg et al. (2005), Tiihonen et al. (2010), and Yatsunenko et al. (2012).Besides the aging process, the differences in gut microbiota observed across aging might be due to various environmental confounders, which include demographic and lifestyle characteristics at different geographic locations. To evaluate the effect of aging on gut microbiota, a longitudinal analysis should be carried out on the same cohort with all the demographic data available.
Changing Brains
Bryan Kolb, ... Robbin Gibb, in Progress in Brain Research, 2013
4.8 Intestinal flora
Gut microbiota have adapted to a symbiotic relationship with many animals. Soon after birth, the gut of mammals is populated by a variety of indigenous microbes that influence both gut and liver functions (e.g., Bjorkholm et al., 2009; Hooper and Gordon, 2001). There are many similarities in the neurochemical organization of the enteric and central nervous systems, so it is reasonable to speculate that gut microbiota might influence brain function. Indeed, epidemiological studies have shown an association between neurodevelopmental disorders including autism and schizophrenia and microbial infections early in life (e.g., Finegold et al., 2002; Mittal et al., 2008). Diaz Heijtz et al. (2011) manipulated gut bacteria in newborn mice and found that gut bacteria influence motor and anxiety-like behaviors, which were associated with changes in the production of synaptic-related proteins in cortex and striatum. This finding is important because it provides a mechanism whereby infections during development could influence brain development as well as a reason why results in different laboratories could be different depending upon dietary selection and which gut microbiota are present in the respective colonies.
The Gut Microbiota and Effects on Metabolism
S. Hussey, M. Bergman, in Pathobiology of Human Disease, 2014
Nutritional Supplements
The gut microbiota composition can also be modified by introducing specific nutritional supplements. Prebiotics are selectively fermented nutrients that promote growth of specific preexisting intestinal bacteria, and probiotics are live nonpathogenic microorganisms that supplement the existing population. Can prebiotics and probiotics change the intestinal microbiota enough to impact metabolic diseases? Early studies suggest yes. For example, when obese women ingested prebiotic dietary fructans for 3 months, population analysis revealed increased levels of Bifidobacterium and Faecalibacterium prausnitzii in the gut microbiota and decreased serum lipopolysaccharide (LPS) levels and also decreased Bacteroides intestinalis, Bacteroides vulgatus, and Propionibacterium and diminished fat mass levels. Oral administration of Lactobacillus reuteri GMNL-263 improves insulin resistance and ameliorates hepatic steatosis in high-fructose-fed rats. These studies hold promise for nutritional manipulation of the gut microbiota to favor better metabolic outcomes.
Gut microbiota-derived metabolites in host physiology
Francesco Strati, Federica Facciotti, in Metabolomics Perspectives, 2022
Abstract
Gut microbiota is a master regulator of host physiology. Intestinal microbes produce numerous metabolites through primary and secondary metabolic pathways, and many of which are dependent on host diet. The effects exerted by these microbial-derived metabolites represent the combined output of host-microbes interactions, which influence host energy metabolism, development and function of the immune system, maintenance of mucosal integrity, as well as intestinal microbiota community dynamics. In this chapter, we provide an overview of the methodologies used in metabolomic studies to dissect and understand host-microbiota interactions. Furthermore, we discuss the current knowledge on specific microbial-derived metabolites, notably secondary bile acids, short chain fatty acids, and tryptophan metabolites and their role in affecting host health.
Relationship Between Gut Microbiota, Energy Metabolism, and Obesity
G.J. Bakker, M. Nieuwdorp, in The Microbiota in Gastrointestinal Pathophysiology, 2017
Abstract
The gut microbiota is increasingly recognized as an important regulator of energy metabolism. Alterations in gut microbiota composition have been associated with the presence of obesity, which is accompanied by a low-grade inflammatory state and increases the risk of several diseases, including type 2 diabetes mellitus. Although causality still needs to be proven, there is a large body of evidence supporting a role for the gut microbiota in the development of obesity and the associated diseases. In this regard, prospective human trials targeting the gut microbiota, using, for example, probiotics or fecal transplantation, are needed. This approach may yield exciting novel diagnostic markers as well as therapeutic targets. In this chapter, we will describe several mechanisms, which may contribute to the influence of the gut microbiota on metabolism, including direct energy extraction from the diet, production of short-chain fatty acids, and bacterial translocation.
