scholarly journals Variation of glucoraphanin metabolismin vivoandex vivoby human gut bacteria

2011 ◽  
Vol 106 (3) ◽  
pp. 408-416 ◽  
Author(s):  
Fei Li ◽  
Meredith A. J. Hullar ◽  
Shirley A. A. Beresford ◽  
Johanna W. Lampe

Glucosinolates, phytochemicals found in cruciferous vegetables, are metabolised to bioactive isothiocyanates (ITC) by certain bacteria in the human gut. Substantial individual variation in urinary ITC excretion has been observed in previous cruciferous vegetable-feeding studies. We hypothesised that individual differences in gut microbial community contribute to the observed variation in glucosinolate metabolism, i.e. gut microbiota composition between high- and low-ITC excreters differs. We recruited twenty-three healthy individuals and fed them a standardised meal containing 200 g of cooked broccoli. After the meal, 24 h urinary ITC excretion was measured. Study participants with the highest (n5) and lowest (n5) ITC excretion provided faecal samples forex vivobacterial cultivation with 50 μm-glucoraphanin, the major glucosinolate found in broccoli. When grownex vivo,faecal bacteria from the selected high-ITC excreters were able to degrade more glucoraphanin than those from the low-ITC excreters (P = 0·05). However, bacterial fingerprints of faecal andex vivoculture microbiota revealed no statistically significant differences between the high- and low-ITC excreters in terminal restriction fragment length polymorphism analysis of the bacterial 16S ribosomal RNA gene. In conclusion, glucosinolate degradation by faecal bacteriaex vivomay be associated within vivobacterial glucosinolate metabolism capacity, but no direct link to specific bacterial species could be established, possibly due to the complexity and functional redundancy of the gut microbiota.

2021 ◽  
Vol 12 ◽  
Author(s):  
Sudeep Ghimire ◽  
Supapit Wongkuna ◽  
Ranjini Sankaranarayanan ◽  
Elizabeth P. Ryan ◽  
G. Jayarama Bhat ◽  
...  

Dietary fiber and flavonoids have substantial influence on the human gut microbiota composition that significantly impact health. Recent studies with dietary supplements such as quercetin and rice bran have shown beneficial impacts on the host alongside a positive influence of the gut microbiota. The specific bacterial species impacted by quercetin or rice bran in the diet is not well understood. In this study, we used a minibioreactor array system as a model to determine the effect of quercetin and rice bran individually, as well as in combination, on gut microbiota without the confounding host factors. We found that rice bran exerts higher shift in gut microbiome composition when compared to quercetin. At the species level, Acidaminococcus intestini was the only significantly enriched taxa when quercetin was supplemented, while 15 species were enriched in rice bran supplementation and 13 were enriched when quercetin and rice bran were supplemented in combination. When comparing the short chain fatty acid production, quercetin supplementation increased isobutyrate production while propionate dominated the quercetin and rice bran combined group. Higher levels of propionate were highly correlated to the lower abundance of the potentially pathogenic Enterobacteriaceae family. These findings suggest that the combination of quercetin and rice bran serve to enrich beneficial bacteria and reduce potential opportunistic pathogens. In vivo studies are necessary to determine how this synergy of quercetin and rice bran on microbiota impact host health.


Author(s):  
Thomas Gurry ◽  
Le Thanh Tu Nguyen ◽  
Xiaoqian Yu ◽  
Eric J Alm

AbstractThe human gut microbiota is known for its highly heterogeneous composition across different individuals. However, relatively little is known about functional differences in its ability to ferment complex polysaccharides. Through ex vivo measurements from healthy human donors, we show that individuals vary markedly in their microbial metabolic phenotypes (MMPs), mirroring differences in their microbiota composition, and resulting in the production of different quantities and proportions of Short Chain Fatty Acids (SCFAs) from the same inputs. We also show that aspects of these MMPs can be predicted from composition using 16S rRNA sequencing. From experiments performed using the same dietary fibers in vivo, we demonstrate that an ingested bolus of fiber is almost entirely consumed by the microbiota upon passage. We leverage our ex vivo data to construct a model of SCFA production and absorption in vivo, and argue that inter-individual differences in quantities of absorbed SCFA are directly related to differences in production. Taken together, these data suggest that personalized dietary fiber supplementation based on an individual’s MMP is an attractive therapeutic strategy for treating diseases associated with SCFA production.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254004
Author(s):  
Thomas Gurry ◽  
Le Thanh Tu Nguyen ◽  
Xiaoqian Yu ◽  
Eric J. Alm

The human gut microbiota is known for its highly heterogeneous composition across different individuals. However, relatively little is known about functional differences in its ability to ferment complex polysaccharides. Through ex vivo measurements from healthy human donors, we show that individuals vary markedly in their microbial metabolic phenotypes (MMPs), mirroring differences in their microbiota composition, and resulting in the production of different quantities and proportions of Short Chain Fatty Acids (SCFAs) from the same inputs. We also show that aspects of these MMPs can be predicted from composition using 16S rRNA sequencing. From experiments performed using the same dietary fibers in vivo, we demonstrate that an ingested bolus of fiber is almost entirely consumed by the microbiota upon passage. We leverage our ex vivo data to construct a model of SCFA production and absorption in vivo, and argue that inter-individual differences in quantities of absorbed SCFA are directly related to differences in production. Though in vivo studies are required to confirm these data in the context of the gut, in addition to in vivo read outs of SCFAs produced in response to specific fiber spike-ins, these data suggest that optimizing SCFA production in a given individual through targeted fiber supplementation requires quantitative understanding of their MMP.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Shi Huang ◽  
Shuaiming Jiang ◽  
Dongxue Huo ◽  
Celeste Allaband ◽  
Mehrbod Estaki ◽  
...  

Abstract Background Improving probiotic engraftment in the human gut requires a thorough understanding of the in vivo adaptive strategies of probiotics in diverse contexts. However, for most probiotic strains, these in vivo genetic processes are still poorly characterized. Here, we investigated the effects of gut selection pressures from human, mice, and zebrafish on the genetic stability of a candidate probiotic Lactiplantibacillus plantarum HNU082 (Lp082) as well as its ecological and evolutionary impacts on the indigenous gut microbiota using shotgun metagenomic sequencing in combination with isolate resequencing methods. Results We combined both metagenomics and isolate whole genome sequencing approaches to systematically study the gut-adaptive evolution of probiotic L. plantarum and the ecological and evolutionary changes of resident gut microbiomes in response to probiotic ingestion in multiple host species. Independent of host model, Lp082 colonized and adapted to the gut by acquiring highly consistent single-nucleotide mutations, which primarily modulated carbohydrate utilization and acid tolerance. We cultivated the probiotic mutants and validated that these gut-adapted mutations were genetically stable for at least 3 months and improved their fitness in vitro. In turn, resident gut microbial strains, especially competing strains with Lp082 (e.g., Bacteroides spp. and Bifidobacterium spp.), actively responded to Lp082 engraftment by accumulating 10–70 times more evolutionary changes than usual. Human gut microbiota exhibited a higher ecological and genetic stability than that of mice. Conclusions Collectively, our results suggest a highly convergent adaptation strategy of Lp082 across three different host environments. In contrast, the evolutionary changes within the resident gut microbes in response to Lp082 were more divergent and host-specific; however, these changes were not associated with any adverse outcomes. This work lays a theoretical foundation for leveraging animal models for ex vivo engineering of probiotics to improve engraftment outcomes in humans.


2020 ◽  
Author(s):  
Y Liu ◽  
AL Heath ◽  
B Galland ◽  
N Rehrer ◽  
L Drummond ◽  
...  

© 2020 American Society for Microbiology. Dietary fiber provides growth substrates for bacterial species that belong to the colonic microbiota of humans. The microbiota degrades and ferments substrates, producing characteristic short-chain fatty acid profiles. Dietary fiber contains plant cell wall-associated polysaccharides (hemicelluloses and pectins) that are chemically diverse in composition and structure. Thus, depending on plant sources, dietary fiber daily presents the microbiota with mixtures of plant polysaccharides of various types and complexity. We studied the extent and preferential order in which mixtures of plant polysaccharides (arabinoxylan, xyloglucan, β-glucan, and pectin) were utilized by a coculture of five bacterial species (Bacteroides ovatus, Bifidobacterium longum subspecies longum, Megasphaera elsdenii, Ruminococcus gnavus, and Veillonella parvula). These species are members of the human gut microbiota and have the biochemical capacity, collectively, to degrade and ferment the polysaccharides and produce short-chain fatty acids (SCFAs). B. ovatus utilized glycans in the order β-glucan, pectin, xyloglucan, and arabinoxylan, whereas B. longum subsp. longum utilization was in the order arabinoxylan, arabinan, pectin, and β-glucan. Propionate, as a proportion of total SCFAs, was augmented when polysaccharide mixtures contained galactan, resulting in greater succinate production by B. ovatus and conversion of succinate to propionate by V. parvula. Overall, we derived a synthetic ecological community that carries out SCFA production by the common pathways used by bacterial species for this purpose. Systems like this might be used to predict changes to the emergent properties of the gut ecosystem when diet is altered, with the aim of beneficially affecting human physiology. This study addresses the question as to how bacterial species, characteristic of the human gut microbiota, collectively utilize mixtures of plant polysaccharides such as are found in dietary fiber. Five bacterial species with the capacity to degrade polymers and/or produce acidic fermentation products detectable in human feces were used in the experiments. The bacteria showed preferential use of certain polysaccharides over others for growth, and this influenced their fermentation output qualitatively. These kinds of studies are essential in developing concepts of how the gut microbial community shares habitat resources, directly and indirectly, when presented with mixtures of polysaccharides that are found in human diets. The concepts are required in planning dietary interventions that might correct imbalances in the functioning of the human microbiota so as to support measures to reduce metabolic conditions such as obesity.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Fatemeh Ostadhossein ◽  
Parikshit Moitra ◽  
Esra Altun ◽  
Debapriya Dutta ◽  
Dinabandhu Sar ◽  
...  

AbstractDental plaques are biofilms that cause dental caries by demineralization with acidogenic bacteria. These bacteria reside inside a protective sheath which makes any curative treatment challenging. We propose an antibiotic-free strategy to disrupt the biofilm by engineered clustered carbon dot nanoparticles that function in the acidic environment of the biofilms. In vitro and ex vivo studies on the mature biofilms of Streptococcus mutans revealed >90% biofilm inhibition associated with the contact-mediated interaction of nanoparticles with the bacterial membrane, excessive reactive oxygen species generation, and DNA fragmentation. An in vivo examination showed that these nanoparticles could effectively suppress the growth of S. mutans. Importantly, 16S rRNA analysis of the dental microbiota showed that the diversity and richness of bacterial species did not substantially change with nanoparticle treatment. Overall, this study presents a safe and effective approach to decrease the dental biofilm formation without disrupting the ecological balance of the oral cavity.


2020 ◽  
Vol 69 (6) ◽  
pp. 854-863
Author(s):  
Catherine O'Reilly ◽  
Órla O’Sullivan ◽  
Paul D. Cotter ◽  
Paula M. O’Connor ◽  
Fergus Shanahan ◽  
...  

Introduction. Management of steroid-refractory ulcerative colitis has predominantly involved treatment with systemic cyclosporine A (CyA) and infliximab. Aim. The purpose of this study was to assess the effect of using a colon-targeted delivery system CyA formulation on the composition and functionality of the gut microbiota. Methodology. Ex vivo faecal fermentations from six healthy control subjects were treated with coated minispheres (SmPill) with (+) or without (−) CyA and compared with a non-treated control in a model colon system. In addition, the in vivo effect of the SmPill+CyA formulation was investigated by analysing the gut microbiota in faecal samples collected before the administration of SmPill+CyA and after 7 consecutive days of administration from eight healthy subjects who participated in a pilot study. Results. Analysis of faecal samples by 16S rRNA gene sequencing indicated little variation in the diversity or relative abundance of the microbiota composition before or after treatment with SmPill minispheres with or without CyA ex vivo or with CyA in vivo. Short-chain fatty acid profiles were evaluated using gas chromatography, showing an increase in the concentration of n-butyrate (P=0.02) and acetate (P=0.32) in the faecal fermented samples incubated in the presence of SmPill minispheres with or without CyA. This indicated that increased acetate and butyrate production was attributed to a component of the coated minispheres rather than an effect of CyA on the microbiota. Butyrate and acetate levels also increased significantly (P=0.05 for both) in the faecal samples of healthy individuals following 7 days’ treatment with SmPill+CyA in the pilot study. Conclusion. SmPill minispheres with or without CyA at the clinically relevant doses tested here have negligible direct effects on the gut microbiota composition. Butyrate and acetate production increased, however, in the presence of the beads in an ex vivo model system as well as in vivo in healthy subjects. Importantly, this study also demonstrates the relevance and value of using ex vivo colon models to predict the in vivo impact of colon-targeted drugs directly on the gut microbiota.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jianan Zhang ◽  
Morgan E. Walker ◽  
Katherine Z. Sanidad ◽  
Hongna Zhang ◽  
Yanshan Liang ◽  
...  

AbstractEmerging research supports that triclosan (TCS), an antimicrobial agent found in thousands of consumer products, exacerbates colitis and colitis-associated colorectal tumorigenesis in animal models. While the intestinal toxicities of TCS require the presence of gut microbiota, the molecular mechanisms involved have not been defined. Here we show that intestinal commensal microbes mediate metabolic activation of TCS in the colon and drive its gut toxicology. Using a range of in vitro, ex vivo, and in vivo approaches, we identify specific microbial β-glucuronidase (GUS) enzymes involved and pinpoint molecular motifs required to metabolically activate TCS in the gut. Finally, we show that targeted inhibition of bacterial GUS enzymes abolishes the colitis-promoting effects of TCS, supporting an essential role of specific microbial proteins in TCS toxicity. Together, our results define a mechanism by which intestinal microbes contribute to the metabolic activation and gut toxicity of TCS, and highlight the importance of considering the contributions of the gut microbiota in evaluating the toxic potential of environmental chemicals.


2019 ◽  
Vol 47 (06) ◽  
pp. 1381-1404 ◽  
Author(s):  
Jin Wang ◽  
Li Shao ◽  
Tai Rao ◽  
Wei Zhang ◽  
Wei-Hua Huang

Oplopanax elatus (Nakai) Nakai is an oriental herb, the polyyne-enriched fraction of which (PEFO) showed anticolorectal cancer (anti-CRC) effects. Other concomitant components, which are inevitably bio-transformed by gut microbiota after oral administration, might be interfere with the pharmacodynamics of polyynes. However, the influence of human gut microbiota on molecules from O. elatus possessing anticancer activity are yet unknown. In this study, the compounds in PEFO and PEFO incubated with human gut microbiota were analyzed and tentatively identified by HPLC-DAD-QTOF-MS. Two main polyynes ((3[Formula: see text]8[Formula: see text]-falcarindiol and oplopandiol) were not significantly decomposed, but some new unknown molecules were discovered during incubation. However, the antiproliferative effects of PEFO incubated with human gut microbiota for 72 h (PEFO I) were much lower than that of PEFO on HCT-116, SW-480, and HT-29 cells. Furthermore, PEFO possessed better anti-CRC activity in vivo, and significantly induced apoptosis of the CRC cells, which was associated with activation of caspase-3 according to the Western-blot results ([Formula: see text]). These results suggest anticolorectal cancer activity of polyynes might be antagonized by some bio-converted metabolites after incubation with human gut microbiota. Therefore, it might be better for CRC prevention if the polyynes could be orally administrated as purified compounds.


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