scholarly journals Applying mass spectrometry-based assays to explore gut microbial metabolism and associations with disease

2020 ◽  
Vol 58 (5) ◽  
pp. 719-732 ◽  
Author(s):  
Liam M. Heaney

AbstractThe workings of the gut microbiome have gained increasing interest in recent years through the mounting evidence that the microbiota plays an influential role in human health and disease. A principal focus of this research seeks to further understand the production of metabolic by-products produced by bacteria resident in the gut, and the subsequent interaction of these metabolites on host physiology and pathophysiology of disease. Gut bacterial metabolites of interest are predominately formed via metabolic breakdown of dietary compounds including choline and ʟ-carnitine (trimethylamine N-oxide), amino acids (phenol- and indole-containing uremic toxins) and non-digestible dietary fibers (short-chain fatty acids). Investigations have been accelerated through the application of mass spectrometry (MS)-based assays to quantitatively assess the concentration of these metabolites in laboratory- and animal-based experiments, as well as for direct circulating measurements in clinical research populations. This review seeks to explore the impact of these metabolites on disease, as well as to introduce the application of MS for those less accustomed to its use as a clinical tool, highlighting pertinent research related to its use for measurements of gut bacteria-mediated metabolites to further understand their associations with disease.

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.


2020 ◽  
Vol 21 (8) ◽  
pp. 785-798 ◽  
Author(s):  
Abedin Abdallah ◽  
Evera Elemba ◽  
Qingzhen Zhong ◽  
Zewei Sun

The gastrointestinal tract (GIT) of humans and animals is host to a complex community of different microorganisms whose activities significantly influence host nutrition and health through enhanced metabolic capabilities, protection against pathogens, and regulation of the gastrointestinal development and immune system. New molecular technologies and concepts have revealed distinct interactions between the gut microbiota and dietary amino acids (AAs) especially in relation to AA metabolism and utilization in resident bacteria in the digestive tract, and these interactions may play significant roles in host nutrition and health as well as the efficiency of dietary AA supplementation. After the protein is digested and AAs and peptides are absorbed in the small intestine, significant levels of endogenous and exogenous nitrogenous compounds enter the large intestine through the ileocaecal junction. Once they move in the colonic lumen, these compounds are not markedly absorbed by the large intestinal mucosa, but undergo intense proteolysis by colonic microbiota leading to the release of peptides and AAs and result in the production of numerous bacterial metabolites such as ammonia, amines, short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs), hydrogen sulfide, organic acids, and phenols. These metabolites influence various signaling pathways in epithelial cells, regulate the mucosal immune system in the host, and modulate gene expression of bacteria which results in the synthesis of enzymes associated with AA metabolism. This review aims to summarize the current literature relating to how the interactions between dietary amino acids and gut microbiota may promote host nutrition and health.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2335
Author(s):  
Gabriella Pinto ◽  
Sabrina De Pascale ◽  
Maria Aponte ◽  
Andrea Scaloni ◽  
Francesco Addeo ◽  
...  

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6–7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut’s appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.


2021 ◽  
Vol 11 (11) ◽  
pp. 5112
Author(s):  
Julia Vega ◽  
Geniane Schneider ◽  
Bruna R. Moreira ◽  
Carolina Herrera ◽  
José Bonomi-Barufi ◽  
...  

Macroalgae belong to a diverse group of organisms that could be exploited for biomolecule application. Among the biocompounds found in this group, mycosporine-like amino acids (MAAs) are highlighted mainly due to their photoprotection, antioxidant properties, and high photo and thermo-stability, which are attractive characteristics for the development of cosmeceutical products. Therefore, here we revise published data about MAAs, including their biosynthesis, biomass production, extraction, characterization, identification, purification, and bioactivities. MAAs can be found in many algae species, but the highest concentrations are found in red macroalgae, mainly in the order Bangiales, as Porphyra spp. In addition to the species, the content of MAAs can vary depending on environmental factors, of which solar radiation and nitrogen availability are the most influential. MAAs can confer photoprotection due to their capacity to absorb ultraviolet radiation or reduce the impact of free radicals on cells, among other properties. To extract these compounds, different approaches can be used. The efficiency of these methods can be evaluated with characterization and identification using high performance liquid chromatography (HPLC), associated with other apparatus such as mass spectrometry (MS) and nuclear magnetic resonance (NMR). Therefore, the data presented in this review allow a broad comprehension of MAAs and show perspectives for their inclusion in cosmeceutical products.


2016 ◽  
Vol 7 (4) ◽  
pp. 1805-1813 ◽  
Author(s):  
Junyi Yang ◽  
Devin J. Rose

A diet high in whole grains, dry beans, and certain vegetables that contributed dietary fiber, plant protein, and B vitamins resulted in high short chain fatty acids, while a diet high in diary and processed meats that provided cholesterol and little fiber resulted in high branched chain fatty acids and ammonia during fecal fermentation of inulin.


Animals ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 149
Author(s):  
Haibo Fu ◽  
Wenjing Li

The division of hard and soft feces is an effective digestion strategy in the order Lagomorpha. Although previous studies have reported that hard and soft feces differ in morphology and component, the discrepancy in the microbiome remains unclear. This study explored the microbiomes of hard and soft feces in plateau pikas by sequencing the V3 and V4 regions of 16S rDNA. We found that hard feces harbored higher Firmicutes, while soft feces harbored higher Akkermansia. Increased rare bacterial taxa were observed in hard feces compared with soft feces. Moreover, hard and soft feces displayed a greater difference in terms of core operational taxonomy units (OTUs) compared to the total OTUs. The soft feces showed enhancements in all predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) functions, indicating an advancing microbial metabolism compared to hard feces. The significantly upregulated pathways in soft feces were mainly enriched in metabolism of energy and carbohydrate, glycan biosynthesis, cofactors and vitamins, and amino acids—all of which are associated with increased contents of microbial proteins, vitamins, and short-chain fatty acids. Our study reports, for the first time, the differential microbiomes between hard and soft feces of pikas and provides direction for the future studies on cecotrophy.


2009 ◽  
Vol 55 (9) ◽  
pp. 1615-1626 ◽  
Author(s):  
Dennis J Dietzen ◽  
Piero Rinaldo ◽  
Ronald J Whitley ◽  
William J Rhead ◽  
W Harry Hannon ◽  
...  

Abstract Background: Almost all newborns in the US are screened at birth for multiple inborn errors of metabolism using tandem mass spectrometry. Screening tests are designed to be sufficiently sensitive so that cases are not missed. The NACB recognized a need for standard guidelines for laboratory confirmation of a positive newborn screen such that all babies would benefit from equal and optimal follow-up by confirmatory testing. Methods: A committee was formed to review available data pertaining to confirmatory testing. The committee evaluated previously published guidelines, published methodological and clinical studies, clinical case reports, and expert opinion to support optimal confirmatory testing. Grading was based on guidelines adopted from criteria derived from the US Preventive Services Task Force and on the strength of recommendations and the quality of the evidence. Three primary methods of analyte measurement were evaluated for confirmatory testing including measurement of amino acids, organic acids, and carnitine esters. The committee graded the evidence for diagnostic utility of each test for the screened conditions. Results: Ample data and experience were available to make strong recommendations for the practice of analyzing amino acids, organic acids, and acylcarnitines. Likewise, strong recommendations were made for the follow-up test menu for many disorders, particularly those with highest prevalence. Fewer data exist to determine the impact of newborn screening on patient outcomes in all but a few disorders. The guidelines also provide an assessment of developing technology that will fuel a refinement of current practice and ultimate expansion of the diseases detectable by tandem mass spectrometry. Conclusions: Guidelines are provided for optimal follow-up testing for positive newborn screens using tandem mass spectrometry. The committee regards these tests as reliable and currently optimal for follow-up testing. .


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