scholarly journals If you eat it, or secrete it, they will grow: the expanding list of nutrients utilized by human gut bacteria

2020 ◽  
Author(s):  
Robert W.P. Glowacki ◽  
Eric C. Martens
Keyword(s):  
Synthetic Biology ◽  
Nutrient Utilization ◽  
Gut Bacteria ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Human Gut ◽  
Host Diet ◽  
Health And Disease ◽  
Gut Symbionts ◽  
Polysaccharide Utilization Loci

In order to persist, successful bacterial inhabitants of the human gut need to adapt to changing nutrient conditions, which are influenced by host diet and a variety of other factors. For members of the Bacteroidetes and several other phyla, this has resulted in diversification of a variety of enzyme-based systems that equip them to sense and utilize carbohydrate-based nutrients from host, diet, and bacterial origin. In this review, we focus first on human gut Bacteroides and describe recent findings regarding polysaccharide utilization loci (PULs) and the mechanisms of the multi-protein systems they encode, including their regulation and the expanding diversity of substrates that they target. Next, we highlight previously understudied substrates such as monosaccharides, nucleosides, and Maillard reaction products that can also affect the gut microbiota by feeding symbionts that possess specific systems for their metabolism. Since some pathogens preferentially utilize these nutrients, they may represent nutrient niches competed for by commensals and pathogens. Finally, we address recent work to describe nutrient acquisition mechanisms in other important gut species such as those belonging to the Gram-positive anaerobic phyla Actinobacteria and Firmicutes, as well as the Proteobacteria. Because gut bacteria contribute to many aspects of health and disease, we showcase advances in the field of synthetic biology, which seeks to engineer novel, diet-controlled nutrient utilization pathways within gut symbionts to create rationally designed live therapeutics.

scholarly journals Microbiota functional activity biosensors for characterizing nutrient utilization in vivo

2020 ◽  
Author(s):  
Darryl A. Wesener ◽  
Zachary W. Beller ◽  
Samantha L. Peters ◽  
Amir Rajabi ◽  
Gianluca Dimartino ◽  
...  
Keyword(s):  
Functional Activity ◽  
Nutrient Utilization ◽  
Human Gut ◽  
Human Diet ◽  
Surface Enhanced ◽  
Health And Disease ◽  
Gnotobiotic Mice ◽  
Functional States ◽  
Covalently Linked

AbstractMethods for measuring gut microbiota biochemical activities in vivo are needed to characterize its functional states in health and disease. To illustrate one approach, an arabinan-containing polysaccharide was purified from pea fiber, its structure defined, and forward genetic and proteomic analyses used to compare its effects, versus unfractionated pea fiber and sugar beet arabinan, on a human gut bacterial strain consortium in gnotobiotic mice. We produced ‘Microbiota Functional Activity Biosensors’ (MFABs) consisting of glycans covalently-linked to the surface of fluorescent paramagnetic microscopic glass beads. Three MFABs, each containing a unique glycan/fluorophore combination, were simultaneously orally gavaged into gnotobiotic mice, recovered from their intestines, and analyzed to directly quantify bacterial metabolism of structurally distinct arabinans in different human diet contexts. Colocalizing pea-fiber arabinan and another polysaccharide (glucomannan) on the bead surface enhanced in vivo metabolism of glucomannan. MFABs represent a potentially versatile platform for developing new prebiotics and more nutritious foods.

Activation of the transcription factor Nrf2 in macrophages, Caco-2 cells and intact human gut tissue by Maillard reaction products and coffee

Amino Acids ◽  
2012 ◽  
Vol 44 (6) ◽  
pp. 1427-1439 ◽  
Author(s):  
Tanja Sauer ◽  
Martin Raithel ◽  
Jürgen Kressel ◽  
Gerald Münch ◽  
Monika Pischetsrieder
Keyword(s):  
Transcription Factor ◽  
Maillard Reaction ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Human Gut

scholarly journals The Controversial Role of Human Gut Lachnospiraceae

2020 ◽  
Vol 8 (4) ◽  
pp. 573 ◽  
Author(s):  
Mirco Vacca ◽  
Giuseppe Celano ◽  
Francesco Maria Calabrese ◽  
Piero Portincasa ◽  
Marco Gobbetti ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Gut Microbiota ◽  
Short Chain Fatty Acids ◽  
Intestinal Lumen ◽  
Human Gut ◽  
The Core ◽  
Host Diet ◽  
Health And Disease ◽  
Host Physiology

The complex polymicrobial composition of human gut microbiota plays a key role in health and disease. Lachnospiraceae belong to the core of gut microbiota, colonizing the intestinal lumen from birth and increasing, in terms of species richness and their relative abundances during the host’s life. Although, members of Lachnospiraceae are among the main producers of short-chain fatty acids, different taxa of Lachnospiraceae are also associated with different intra- and extraintestinal diseases. Their impact on the host physiology is often inconsistent across different studies. Here, we discuss changes in Lachnospiraceae abundances according to health and disease. With the aim of harnessing Lachnospiraceae to promote human health, we also analyze how nutrients from the host diet can influence their growth and how their metabolites can, in turn, influence host physiology.

scholarly journals Extensive transfer of genes for edible seaweed digestion from marine to human gut bacteria

2020 ◽  
Author(s):  
Nicholas A. Pudlo ◽  
Gabriel Vasconcelos Pereira ◽  
Jaagni Parnami ◽  
Melissa Cid ◽  
Stephanie Markert ◽  
...  
Keyword(s):  
Future Generation ◽  
Gut Bacteria ◽  
Mobile Dna ◽  
Terrestrial Plants ◽  
Human Gut ◽  
Edible Seaweed ◽  
Edible Macroalgae ◽  
Dna Elements ◽  
Gut Symbionts ◽  
Global Exchange

SummaryHumans harbor numerous species of colonic bacteria that digest the fiber polysaccharides in commonly consumed terrestrial plants. More recently in history, regional populations have consumed edible macroalgae seaweeds containing unique polysaccharides. It remains unclear how extensively gut bacteria have adapted to digest these nutrients and use these abilities to colonize microbiomes around the world, especially outside Asia. Here, we show that the ability of gut bacteria to digest seaweed polysaccharides is more pervasive than previously appreciated. Using culture-based approaches, we show that known Bacteroides genes involved in seaweed degradation have mobilized into many members of this genus. We also identify several previously unknown examples of marine bacteria-derived genes, and their corresponding mobile DNA elements, that are involved in degrading seaweed polysaccharides. Some of these genes reside in gut-resident, Gram-positive Firmicutes, for which phylogenetic analysis suggests an origin in the Epulopiscium gut symbionts of marine fishes. Our results are important for understanding the metabolic plasticity of the human gut microbiome, the global exchange of genes in the context of dietary selective pressures and identifying new functions that can be introduced or engineered to design and fill orthogonal niches for a future generation of engineered probiotics.

scholarly journals Metabolic and enzymatic elucidation of cooperative degradation of red seaweed agarose by two human gut bacteria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eun Ju Yun ◽  
Sora Yu ◽  
Na Jung Park ◽  
Yoonho Cho ◽  
Na Ree Han ◽  
...  
Keyword(s):  
Bifidobacterium Longum ◽  
Gut Bacteria ◽  
Specific Gene ◽  
Red Seaweed ◽  
Human Gut ◽  
Metabolic Cooperation ◽  
Red Seaweeds ◽  
Metabolic Intermediates ◽  
Gut Symbionts ◽  
Related Enzyme

AbstractVarious health beneficial outcomes associated with red seaweeds, especially their polysaccharides, have been claimed, but the molecular pathway of how red seaweed polysaccharides are degraded and utilized by cooperative actions of human gut bacteria has not been elucidated. Here, we investigated the enzymatic and metabolic cooperation between two human gut symbionts, Bacteroides plebeius and Bifidobacterium longum ssp. infantis, with regard to the degradation of agarose, the main carbohydrate of red seaweed. More specifically, B. plebeius initially decomposed agarose into agarotriose by the actions of the enzymes belonging to glycoside hydrolase (GH) families 16 and 117 (i.e., BpGH16A and BpGH117) located in the polysaccharide utilization locus, a specific gene cluster for red seaweed carbohydrates. Then, B. infantis extracted energy from agarotriose by the actions of two agarolytic β-galactosidases (i.e., Bga42A and Bga2A) and produced neoagarobiose. B. plebeius ultimately acted on neoagarobiose by BpGH117, resulting in the production of 3,6-anhydro-l-galactose, a monomeric sugar possessing anti-inflammatory activity. Our discovery of the cooperative actions of the two human gut symbionts on agarose degradation and the identification of the related enzyme genes and metabolic intermediates generated during the metabolic processes provide a molecular basis for agarose degradation by gut bacteria.

Metabolism of Maillard reaction products by the human gut microbiota – implications for health

2006 ◽  
Vol 50 (9) ◽  
pp. 847-857 ◽  
Author(s):  
Kieran M. Tuohy ◽  
Davinia J. S. Hinton ◽  
Sarah J. Davies ◽  
M. James C. Crabbe ◽  
Glenn R. Gibson ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Maillard Reaction ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Human Gut ◽  
Human Gut Microbiota

scholarly journals Symbiotic Human Gut Bacteria with Variable Metabolic Priorities for Host Mucosal Glycans

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Nicholas A. Pudlo ◽  
Karthik Urs ◽  
Supriya Suresh Kumar ◽  
J. Bruce German ◽  
David A. Mills ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Community Dynamics ◽  
Gene Clusters ◽  
Gut Bacteria ◽  
Intestinal Bacterium ◽  
Human Gut ◽  
Metabolic Potential ◽  
Content Type ◽  
Individual Gene ◽  
Host Diet

ABSTRACTMany symbiotic gut bacteria possess the ability to degrade multiple polysaccharides, thereby providing nutritional advantages to their hosts. Like microorganisms adapted to other complex nutrient environments, gut symbionts give different metabolic priorities to substrates present in mixtures. We investigated the responses ofBacteroides thetaiotaomicron, a common human intestinal bacterium that metabolizes more than a dozen different polysaccharides, including theO-linked glycans that are abundant in secreted mucin. Experiments in which mucin glycans were presented simultaneously with other carbohydrates show that degradation of these host carbohydrates is consistently repressed in the presence of alternative substrates, even byB. thetaiotaomicronpreviously acclimated to growth in pure mucin glycans. Experiments with media containing systematically varied carbohydrate cues and genetic mutants reveal that transcriptional repression of genes involved in mucin glycan metabolism is imposed by simple sugars and, in one example that was tested, is mediated through a small intergenic region in a transcript-autonomous fashion. Repression of mucin glycan-responsive gene clusters in two other human gut bacteria,Bacteroides massiliensisandBacteroides fragilis, exhibited variable and sometimes reciprocal responses compared to those ofB. thetaiotaomicron, revealing that these symbionts vary in their preference for mucin glycans and that these differences occur at the level of controlling individual gene clusters. Our results reveal that sensing and metabolic triaging of glycans are complex processes that vary among species, underscoring the idea that these phenomena are likely to be hidden drivers of microbiota community dynamics and may dictate which microorganisms preferentially commit to various niches in a constantly changing nutritional environment.IMPORTANCEHuman intestinal microorganisms impact many aspects of health and disease, including digestion and the propensity to develop disorders such as inflammation and colon cancer. Complex carbohydrates are a major component of the intestinal habitat, and numerous species have evolved and refined strategies to compete for these coveted nutrients. Our findings reveal that individual bacteria exhibit different preferences for carbohydrates emanating from host diet and mucosal secretions and that some of these prioritization strategies are opposite to one another. Thus, we reveal new aspects of how individual bacteria, some with otherwise similar metabolic potential, partition to “preferred niches” in the complex gut ecosystem, which has important and immediate implications for understanding and predicting the behavioral dynamics of this community.

scholarly journals Nanaerobic growth enables direct visualization of dynamic cellular processes in human gut symbionts

2020 ◽  
Author(s):  
Leonor García-Bayona ◽  
Michael J. Coyne ◽  
Noam Hantman ◽  
Paula Montero-Llopis ◽  
Salena Von ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Stress Responses ◽  
Fluorescent Proteins ◽  
Gut Bacteria ◽  
Mucus Layer ◽  
Human Gut ◽  
Terminal Electron Acceptor ◽  
Cellular Processes ◽  
Dynamic Type ◽  
Gut Symbionts

AbstractMechanistic studies of anaerobic gut bacteria have been hindered by the lack of a fluorescent protein system to track and visualize proteins and dynamic cellular processes in actively growing bacteria. Although underappreciated, many gut “anaerobes” are able to respire using oxygen as the terminal electron acceptor. The oxygen continually released from gut epithelial cells creates an oxygen gradient from the mucus layer to the anaerobic lumen (1), with oxygen available to bacteria growing at the mucus layer. Using a combination of analyses, we show that Bacteroides species are metabolically and energetically robust and do not mount stress responses in the presence of 0.10 - 0.14% oxygen, defined as nanaerobic conditions (2). Taking advantage of this metabolic capability, we show that nanaerobic growth provides sufficient oxygen for the maturation of oxygen-requiring fluorescent proteins in Bacteroides species. Type strains of four different Bacteroides species show bright GFP fluorescence when grown nanaerobically versus anaerobically. We compared four different red fluorescent proteins and found that mKate2 yields high fluorescence intensity in our assay. We show that GFP-tagged proteins can be localized in nanaerobically growing bacteria. In addition, we used time-lapse fluorescence microscopy to image dynamic Type VI secretion system processes in metabolically active B. fragilis. The ability to visualize fluorescently-labeled Bacteroides and fluorescently-linked proteins in actively growing nanaerobic gut symbionts ushers in a new age of imaging analyses in these bacteria.SignificanceDespite many recent technological advances to study the human gut microbiota, we still lack a facile system to image dynamic cellular processes in most abundant gut species due to the requirement of oxygen for chromophore maturation of commonly used fluorescent proteins. Here, we took advantage of the ability of anaerobes of the gut microbiota to respire aerobically and grow robustly at 0.10– 0.14% oxygen. This physiologic concentration of oxygen is sufficient for fluorescent proteins to mature, allowing for visualization of biological processes never before imaged in these bacteria. This advance will allow for numerous types of analyses in actively-growing “nanaerobic” gut bacteria including subcellular protein localizations, single-cell analyses, biofilm imaging, and protein interactions with other microbes and the host.

scholarly journals Dietary Maillard Reaction Products: Implications for Human Health and Disease

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S66-S69 ◽  
Author(s):  
J. M Ames
Keyword(s):  
Human Health ◽  
Maillard Reaction ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Advanced Glycation ◽  
Paper Briefly ◽  
Thermally Induced ◽  
Wide Range ◽  
Health Promoting ◽  
Health And Disease

When foods are heat processed, the sugars and lipids react with the proteins they contain via the Maillard and related reactions to form a wide range of products. As a result, the sensory, safety, nutritional and health-promoting attributes of the foods are affected. Reaction products include advanced glycation/lipoxidation endproducts (AGE/ALEs), acrylamide and heterocyclic amines (HAA), all of which may impact on human health and disease. Furthermore, some Maillard reaction products affect the growth of colonic bacteria and thermally-induced modification of dietary protein can affect allergenicity. This paper briefly reviews aspects of the Maillard reaction in food related to human health.

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