scholarly journals Special Issue: Gut Bacteria-Mucus Interaction

2019 ◽  
Vol 7 (1) ◽  
pp. 6 ◽  
Author(s):  
Nathalie Juge

The mucus layer covering the gastrointestinal tract plays a critical role in maintaining a homeostatic relationship with our gut microbiota. [...]

2020 ◽  
Author(s):  
Leonor García-Bayona ◽  
Michael J. Coyne ◽  
Noam Hantman ◽  
Paula Montero-Llopis ◽  
Salena Von ◽  
...  

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.


2020 ◽  
Vol 17 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Pavan K. Mujawdiya ◽  
Suman Kapur

: Quorum Sensing (QS) is a phenomenon in which bacterial cells communicate with each other with the help of several low molecular weight compounds. QS is largely dependent on population density, and it triggers when the concentration of quorum sensing molecules accumulate in the environment and crosses a particular threshold. Once a certain population density is achieved and the concentration of molecules crosses a threshold, the bacterial cells show a collective behavior in response to various chemical stimuli referred to as “auto-inducers”. The QS signaling is crucial for several phenotypic characteristics responsible for bacterial survival such as motility, virulence, and biofilm formation. Biofilm formation is also responsible for making bacterial cells resistant to antibiotics. : The human gut is home to trillions of bacterial cells collectively called “gut microbiota” or “gut microbes”. Gut microbes are a consortium of more than 15,000 bacterial species and play a very crucial role in several body functions such as metabolism, development and maturation of the immune system, and the synthesis of several essential vitamins. Due to its critical role in shaping human survival and its modulating impact on body metabolisms, the gut microbial community has been referred to as “the forgotten organ” by O`Hara et al. (2006) [1]. Several studies have demonstrated that chemical interaction between the members of bacterial cells in the gut is responsible for shaping the overall microbial community. : Recent advances in phytochemical research have generated a lot of interest in finding new, effective, and safer alternatives to modern chemical-based medicines. In the context of antimicrobial research various plant extracts have been identified with Quorum Sensing Inhibitory (QSI) activities among bacterial cells. This review focuses on the mechanism of quorum sensing and quorum sensing inhibitors isolated from natural sources.


2019 ◽  
Vol 97 (9) ◽  
pp. 3741-3757 ◽  
Author(s):  
Nirosh D Aluthge ◽  
Dana M Van Sambeek ◽  
Erin E Carney-Hinkle ◽  
Yanshuo S Li ◽  
Samodha C Fernando ◽  
...  

Abstract A variety of microorganisms inhabit the gastrointestinal tract of animals including bacteria, archaea, fungi, protozoa, and viruses. Pioneers in gut microbiology have stressed the critical importance of diet:microbe interactions and how these interactions may contribute to health status. As scientists have overcome the limitations of culture-based microbiology, the importance of these interactions has become more clear even to the extent that the gut microbiota has emerged as an important immunologic and metabolic organ. Recent advances in metagenomics and metabolomics have helped scientists to demonstrate that interactions among the diet, the gut microbiota, and the host to have profound effects on animal health and disease. However, although scientists have now accumulated a great deal of data with respect to what organisms comprise the gastrointestinal landscape, there is a need to look more closely at causative effects of the microbiome. The objective of this review is intended to provide: 1) a review of what is currently known with respect to the dynamics of microbial colonization of the porcine gastrointestinal tract; 2) a review of the impact of nutrient:microbe effects on growth and health; 3) examples of the therapeutic potential of prebiotics, probiotics, and synbiotics; and 4) a discussion about what the future holds with respect to microbiome research opportunities and challenges. Taken together, by considering what is currently known in the four aforementioned areas, our overarching goal is to set the stage for narrowing the path towards discovering how the porcine gut microbiota (individually and collectively) may affect specific host phenotypes.


Author(s):  
Valentin Sencio ◽  
Marina Gomes Machado ◽  
François Trottein

AbstractBacteria that colonize the human gastrointestinal tract are essential for good health. The gut microbiota has a critical role in pulmonary immunity and host’s defense against viral respiratory infections. The gut microbiota’s composition and function can be profoundly affected in many disease settings, including acute infections, and these changes can aggravate the severity of the disease. Here, we discuss mechanisms by which the gut microbiota arms the lung to control viral respiratory infections. We summarize the impact of viral respiratory infections on the gut microbiota and discuss the potential mechanisms leading to alterations of gut microbiota’s composition and functions. We also discuss the effects of gut microbial imbalance on disease outcomes, including gastrointestinal disorders and secondary bacterial infections. Lastly, we discuss the potential role of the lung–gut axis in coronavirus disease 2019.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna Czech ◽  
Eugeniusz Ryszard Grela ◽  
Martyna Kiesz

AbstractThe aim of the study was to assess the effect of fermented dried soybean (FSBM) and/or fermented rapeseed meal (FRSM) in diets for weaned piglets on production results, nutrient digestibility, gastrointestinal tract histology, and the composition of the gut microbiota. Piglets in the control group received standard diets with soybean meal. Animals in all experimental groups received diets in which a portion of the soybean meal was replaced: in group FR—8% FRSM; in group FR/FS—6% FRSM and 2% FSBM; in group FS/FR—2% FRSM and 6% FSBM and in group FS—8% FSBM. The use of 8% FRSM or 6% FRSM and 2% FSBM in the piglet diets had a positive effect on average daily gains. Piglets from the FR and FR/FS groups had the highest feed conversion rate. Group FS/FR and FS piglets had significantly lower mortality and lower incidence of diarrhoea. Piglets fed a diet with the fermented components, in particular with 8% FRSM or 6% FRSM and 2% FSBM, exhibited a positive effect on the microbiological composition and histology of intestines, which resulted in improved nutrient digestibility coefficients (ATTD and AID).


Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 2029
Author(s):  
Kouya Hattori ◽  
Masahiro Akiyama ◽  
Natsumi Seki ◽  
Kyosuke Yakabe ◽  
Koji Hase ◽  
...  

While poorly-absorbed sugar alcohols such as sorbitol are widely used as sweeteners, they may induce diarrhea in some individuals. However, the factors which determine an individual’s susceptibility to sugar alcohol-induced diarrhea remain unknown. Here, we show that specific gut bacteria are involved in the suppression of sorbitol-induced diarrhea. Based on 16S rDNA analysis, the abundance of Enterobacteriaceae bacteria increased in response to sorbitol consumption. We found that Escherichia coli of the family Enterobacteriaceae degraded sorbitol and suppressed sorbitol-induced diarrhea. Finally, we showed that the metabolism of sorbitol by the E. coli sugar phosphotransferase system helped suppress sorbitol-induced diarrhea. Therefore, gut microbiota prevented sugar alcohol-induced diarrhea by degrading sorbitol in the gut. The identification of the gut bacteria which respond to and degrade sugar alcohols in the intestine has implications for microbiome science, processed food science, and public health.


Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2428
Author(s):  
Małgorzata Guz ◽  
Witold Jeleniewicz ◽  
Anna Malm ◽  
Izabela Korona-Glowniak

A still growing interest between human nutrition in relation to health and disease states can be observed. Dietary components shape the composition of microbiota colonizing our gastrointestinal tract which play a vital role in maintaining human health. There is a strong evidence that diet, gut microbiota and their metabolites significantly influence our epigenome, particularly through the modulation of microRNAs. These group of small non-coding RNAs maintain cellular homeostasis, however any changes leading to impaired expression of miRNAs contribute to the development of different pathologies, including neoplastic diseases. Imbalance of intestinal microbiota due to diet is primary associated with the development of colorectal cancer as well as other types of cancers. In the present work we summarize current knowledge with particular emphasis on diet-microbiota-miRNAs axis and its relation to the development of colorectal cancer.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 69-69
Author(s):  
Dylan Dodd

Abstract The gastrointestinal tract of mammals is home to a dense population of microbes which influence host physiology and health. One of the most concrete ways that the gut microbiota impacts host biology is through the production of hundreds of chemically diverse small molecules. These molecules are absorbed into the bloodstream, where they reach concentrations similar to those achieved by pharmaceuticals and bind host receptors leading to changes in cellular and organ physiology. Here I will summarize recent work from our group and others that show how microbially sourced metabolites alter health and physiology of the host. I will also discuss how mechanistic studies of small molecules from the microbiota are enabling new therapeutic approaches to harness the metabolic potential of the gut microbiota.


2019 ◽  
Vol 25 (37) ◽  
pp. 4946-4967 ◽  
Author(s):  
Anna K. Kiss ◽  
Jakub P. Piwowarski

The popularity of food products and medicinal plant materials containing hydrolysable tannins (HT) is nowadays rapidly increasing. Among various health effects attributable to the products of plant origin rich in gallotannins and/or ellagitannins the most often underlined is the beneficial influence on diseases possessing inflammatory background. Results of clinical, interventional and animal in vivo studies clearly indicate the antiinflammatory potential of HT-containing products, as well as pure ellagitannins and gallotannins. In recent years a great emphasis has been put on the consideration of metabolism and bioavailability of natural products during examination of their biological effects. Conducted in vivo and in vitro studies of polyphenols metabolism put a new light on this issue and indicate the gut microbiota to play a crucial role in the health effects following their oral administration. The aim of the review is to summarize the knowledge about HT-containing products’ phytochemistry and their anti-inflammatory effects together with discussion of the data about observed biological activities with regards to the current concepts on the HTs’ bioavailability and metabolism. Orally administered HT-containing products due to the limited bioavailability of ellagitannins and gallotannins can influence immune response at the level of gastrointestinal tract as well as express modulating effects on the gut microbiota composition. However, due to the chemical changes being a result of their transit through gastrointestinal tract, comprising of hydrolysis and gut microbiota metabolism, the activity of produced metabolites has to be taken into consideration. Studies regarding biological effects of the HTs’ metabolites, in particular urolithins, indicate their strong and structure-dependent anti-inflammatory activities, being observed at the concentrations, which fit the range of their established bioavailability. The impact of HTs on inflammatory processes has been well established on various in vivo and in vitro models, while influence of microbiota metabolites on silencing the immune response gives a new perspective on understanding anti-inflammatory effects attributed to HT containing products, especially their postulated effectiveness in inflammatory bowel diseases (IBD) and cardiovascular diseases.


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