scholarly journals Composition and Functions of the Gut Microbiome in Pediatric Obesity: Relationships with Markers of Insulin Resistance

2021 ◽  
Vol 9 (7) ◽  
pp. 1490
Author(s):  
Camila E. Orsso ◽  
Ye Peng ◽  
Edward C. Deehan ◽  
Qiming Tan ◽  
Catherine J. Field ◽  
...  

The gut microbiome is hypothesized to play a crucial role in the development of obesity and insulin resistance (IR); the pathways linking the microbiome to IR in pediatrics have yet to be precisely characterized. We aimed to determine the relationship between the gut microbiome composition and metabolic functions and IR in children with obesity. In a cross-sectional study, fecal samples from children with obesity (10–16 years old) were collected for taxonomical and functional analysis of the fecal microbiome using shotgun metagenomics. The homeostatic model assessment for insulin resistance (HOMA-IR) was determined using fasting glucose and insulin. Associations between HOMA-IR and α-diversity measures as well as metabolic pathways were evaluated using Spearman correlations; relationships between HOMA-IR and β-diversity were assessed by permutational multivariate analysis of variance. Twenty-one children (nine males; median: age = 12.0 years; BMI z-score = 2.9; HOMA-IR = 3.6) completed the study. HOMA-IR was significantly associated with measures of α-diversity but not with β-diversity. Children with higher HOMA-IR exhibited lower overall species richness, Firmicutes species richness, and overall Proteobacteria species Shannon diversity. Furthermore, HOMA-IR was inversely correlated with the abundance of pathways related to the biosynthesis of lipopolysaccharides, amino acids, and short-chain fatty acids, whereas positive correlations between HOMA-IR and the peptidoglycan biosynthesis pathways were observed. In conclusion, insulin resistance was associated with decreased microbial α-diversity measures and abundance of genes related to the metabolic pathways. Our study provides a framework for understanding the microbial alterations in pediatric obesity.

2021 ◽  
Vol 5 (4) ◽  
Author(s):  
Danxia Yu ◽  
Yaohua Yang ◽  
Jirong Long ◽  
Wanghong Xu ◽  
Qiuyin Cai ◽  
...  

ABSTRACT Background Diet is known to affect human gut microbiome composition; yet, how diet affects gut microbiome functionality remains unclear. Objective We compared the diversity and abundance/presence of fecal microbiome metabolic pathways among individuals according to their long-term diet quality. Methods In 2 longitudinal cohorts, we assessed participants’ usual diets via repeated surveys during 1996–2011 and collected a stool sample in 2015–2018. Participants who maintained a healthy or unhealthy diet (i.e., stayed in the highest or lowest quintile of a healthy diet score throughout follow-up) were selected. Participants were excluded if they reported a history of cancer, cardiovascular disease, diabetes, or hypertension; had diarrhea or constipation in the last 7 d; or used antibiotics in the last 6 mo before stool collection. Functional profiling of shotgun metagenomics was performed using HUMAnN2. Associations of dietary variables and 420 microbial metabolic pathways were evaluated via multivariable-adjusted linear or logistic regression models. Results We included 144 adults (mean age = 64 y; 55% female); 66 had an unhealthy diet and 78 maintained a healthy diet. The healthy diet group had higher Shannon α-diversity indexes of microbial gene families and metabolic pathways (both P < 0.02), whereas β-diversity, as evaluated by Bray-Curtis distance, did not differ between groups (both P > 0.50). At P < 0.01 [false discovery rate (FDR) <0.15], the healthy diet group showed enriched pathways for vitamin and carrier biosynthesis (e.g., tetrahydrofolate, acetyl-CoA, and l-methionine) and tricarboxylic acid (TCA) cycle, and increased degradation (or reduced biosynthesis) of certain sugars [e.g., cytidine monophosphate (CMP)-legionaminate, deoxythymidine diphosphate (dTDP)-l-rhamnose, and sucrose], nucleotides, 4-aminobutanoate, methylglyoxal, sulfate, and aromatic compounds (e.g., catechol and toluene). Meanwhile, several food groups were associated with the CMP-legionaminate biosynthesis pathway at FDR <0.05. Conclusions In a small longitudinal study of generally healthy, older Chinese adults, we found long-term healthy eating was associated with increased α-diversity of microbial gene families and metabolic pathways and altered symbiotic functions relevant to human nutrition and health.


2020 ◽  
Vol 96 (8) ◽  
Author(s):  
Judith Mogouong ◽  
Philippe Constant ◽  
Robert Lavallée ◽  
Claude Guertin

ABSTRACT The gut microbial communities of beetles play crucial roles in their adaptive capacities. Environmental factors such as temperature or nutrition naturally affect the insect microbiome, but a shift in local conditions like the population density on a host tree could also lead to changes in the microbiota. The emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic wood borer that causes environmental and economic damage to ash trees in North America. This study aimed to describe the taxonomic structure of the EAB gut microbiome and explore its potential relationship with borer population size. The number of EAB adults collected per tree through a 75 km transect from an epicenter allowed the creation of distinct classes of population density. The Gammaproteobacteria and Ascomycota predominated in bacterial and fungal communities respectively, as determined by sequencing of the bacterial 16S rRNA gene and the fungal internal transcribed spacer ITS2. Species richness and diversity of the bacterial community showed significant dependence on population density. Moreover, α-diversity and β-diversity analysis revealed some indicator amplicon sequence variants suggesting that the plasticity of the gut microbiome could be related to the EAB population density in host trees.


2004 ◽  
Vol 94 (2) ◽  
pp. 111-121 ◽  
Author(s):  
P.A.V. Borges ◽  
V.K. Brown

AbstractThe arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local–regional species richness relationship was assessed over relatively fine scales: quadrats (= local scale) and within pastures (= regional scale). Mean plot species richness was used as a measure of local species richness (= α diversity) and regional species richness was estimated at the pasture level (= γ diversity) with the ‘first-order-Jackknife’ estimator. Three related issues were addressed: (i) the role of estimated regional species richness and variables operating at the local scale (vegetation structure and diversity) in determining local species richness; (ii) quantification of the relative contributions of α and β diversity to regional diversity using additive partitioning; and (iii) the occurrence of consistent patterns in different years by analysing independently between-year data. Species assemblages of spiders were saturated at the local scale (similar local species richness and increasing β-diversity in richer regions) and were more dependent on vegetational structure than regional species richness. Sucking insect herbivores, by contrast, exhibited a linear relationship between local and regional species richness, consistent with the proportional sampling model. The patterns were consistent between years. These results imply that for spiders local processes are important, with assemblages in a particular patch being constrained by habitat structure. In contrast, for sucking insects, local processes may be insignificant in structuring communities.


2019 ◽  
Author(s):  
Kittipong Chaisiri ◽  
A. Christina Gill ◽  
Alexandr A. Stekolnikov ◽  
Soawapak Hinjoy ◽  
John W. McGarry ◽  
...  

AbstractScrub typhus, caused by a bacterial pathogen (Orientia spp.), is a potentially life-threatening febrile illness widely distributed in the Asia-Pacific region and is emerging elsewhere. The infection is transmitted by the larval stage of trombiculid mites (“chiggers”) that often exhibit low host specificity. Here, we present an analysis of chigger ecology for 38 species sampled from 11 provinces of Thailand and microbiomes for eight widespread species. In total, >16 000 individual chiggers were collected from 1 574 small mammal specimens belonging to 18 species across four horizontally-stratified habitat types. Chigger species richness was positively associated with higher latitudes, dry seasonal conditions, and host maturity; but negatively associated with increased human land use. Human scrub typhus incidence was found to be positively correlated with chigger species richness. The bacterial microbiome of chiggers was highly diverse, with Sphingobium, Mycobacterium, Neisseriaceae and various Bacillales representing the most abundant taxa. Only Leptotrombidium deliense was found to be infected with Orientia. β-diversity, but not α-diversity, was significantly different between chigger species and geographic regions, although not between habitat types. This first field survey of the chigger microbiome provides a framework for future studies on interactions between pathogens and other symbionts in these understudied vectors.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Kittipong Chaisiri ◽  
A. Christina Gill ◽  
Alexandr A. Stekolnikov ◽  
Soawapak Hinjoy ◽  
John W. McGarry ◽  
...  

Abstract Background Scrub typhus, caused by a bacterial pathogen (Orientia spp.), is a potentially life-threatening febrile illness widely distributed in the Asia-Pacific region and is emerging elsewhere. The infection is transmitted by the larval stage of trombiculid mites (“chiggers”) that often exhibit low host specificity. Here, we present an analysis of chigger ecology for 38 species sampled from 11 provinces of Thailand and microbiomes for eight widespread species. Results In total, > 16,000 individual chiggers were collected from 1574 small mammal specimens belonging to 18 species across four horizontally-stratified habitat types. Chigger species richness was positively associated with higher latitudes, dry seasonal conditions, and host maturity; but negatively associated with increased human land use. Human scrub typhus incidence was found to be positively correlated with chigger species richness. The bacterial microbiome of chiggers was highly diverse, with Sphingobium, Mycobacterium, Neisseriaceae and various Bacillales representing the most abundant taxa. Only Leptotrombidium deliense was found to be infected with Orientia and another potential pathogen, Borrelia spp., was frequently detected in pools of this species. β-diversity, but not α-diversity, was significantly different between chigger species and geographic regions, although not between habitat types. Conclusion Our study identified several key environmental and host-derived correlates of chigger species richness across Thailand, which in turn impacted on human scrub typhus incidence. Moreover, this first extensive field survey of the chigger microbiome revealed species- and province-level variation in microbial β-diversity across the country, providing a framework for future studies on interactions between pathogens and other symbionts in these understudied vectors.


2019 ◽  
Vol 15 (5) ◽  
pp. 20190133 ◽  
Author(s):  
Alessandra R. Kortz ◽  
Anne E. Magurran

The world's ecosystems are experiencing unparalleled rates of biodiversity change, with invasive species implicated as one of the drivers that restructure local assemblages. Here we focus on the processes leading to biodiversity change in a biodiversity hotspot, the Brazilian Cerrado. The null expectation that invasion leads to increase in local species richness is supported by our investigation of the grass layer in two key habitats (campo sujo and campo úmido). Our analysis uncovered a linear relationship between total richness and invasive richness at the plot level. However, because the invasive species—even though few in number—are widespread, their contribution to local richness (α-diversity) is offset by their homogenizing influence on composition (β-diversity). We thus identify a mechanism that can help explain the paradox that species richness is not declining in many local assemblages, yet compositional change is exceeding the predictions of ecological theory. As such, our results emphasize the importance of quantifying both α-diversity and β-diversity in assessments of biodiversity change in the contemporary world.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Sabrina Ritz ◽  
Daniela Hahn ◽  
Haleluya T. Wami ◽  
Karin Tegelkamp ◽  
Ulrich Dobrindt ◽  
...  

Abstract Background Exocrine pancreatic insufficiency (EPI) is characterized by the loss of active pancreatic enzymes and a resulting severely reduced food digestion. EPI therapy requires orally applied pancreatic enzyme replacement. The gut microbiome is a known mediator of intestinal diseases and may influence the outcome of EPI and the effects of a pancreatic enzyme replacement therapy (PERT). Here, we analyzed the effects of EPI and PERT on the gut microbiome in the model of pancreatic duct ligated minipigs. Results The microbial community composition in pig feces was analyzed by next generation sequencing of 16S rRNA amplicons. The data were evaluated for α- and β-diversity changes and changes at the different Operational Taxonomic Unit (OTU) levels by Shannon–Wiener and inverse Simpson index calculation as well as by Principal Coordinates Analysis based on Bray–Curtis dissimilarity. Microbial α-diversity was reduced after EPI induction and reverted to nearly healthy state after PERT. Analysis of microbial composition and β-diversity showed distinctive clusters of the three study groups and a change towards a composition comparable to healthy animals upon PERT. The relative abundance of possible pathobionts like Escherichia/Shigella, Acinetobacter or Stenotrophomonas was reduced by PERT. Conclusion These data demonstrate that EPI-induced dysbiosis could be reverted by PERT to a nearly healthy state. Elevated α-diversity and the reduction of bacterial overgrowth after PERT promises benefits for EPI patients. Non-invasive microbiome studies may be useful for EPI therapy monitoring and as marker for response to PERT.


2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1591-1591
Author(s):  
Jirayu Tanprasertsuk ◽  
Justin Shmalberg ◽  
Aashish Jha ◽  
LeeAnn Perry ◽  
Ryan Honaker

Abstract Objectives Dogs share similar gut microbiome (GM) with humans, making them a great model for investigating the effects of probiotics (PR) on GM and health. This randomized control trial examined changes in MB and health outcomes in household dogs after PR supplementation. Methods All dogs recruited were fed human grade cooked food ≥ 1 mo, not fed any cultured food, PR, prebiotics, or on antibiotics ≥ 3 mo, and absent of major diseases. Dogs were randomized to receive a daily dose of PR (20 billion CFU of L. reuteri, P. acidilactici, E. faecium, L. acidophilus, B. animalis, L. fermentum, L. rhamnosus) or placebo (PL) for 4 weeks. Owners completed a health survey and collected stool samples at baseline and 4 weeks after the intervention in both groups. Additional stool samples were collected 2 weeks after stopping the PR in the PR group. GM profiling was performed with metagenomic sequencing. Results Twenty three dogs in the PR and 19 dogs in the PL group completed the trial (5.6 ± 3.0 y, 69% male). PR had no effect on α-diversity. As compared to baseline, changes in β-diversity at the species level in 4.3% of GM were significantly affected by PR at week 4 (P < 0.001) but not at week 6. A significant increase (adj P < 0.01) for ≥ 2-fold in abundance was observed at week 4 as compared to baseline for 41 bacterial taxa, 29 (71%) of which belong in the Lactobacillus genus. The abundance of E. coli also decreased at week 4 in the PR group (2.8 folds, adj P < 0.01). The abundance of these taxa returned to baseline at week 6. Such changes in diversity or abundance were not observed with PL. Dogs fed PR tended to be at a lower risk of diarrhea during the trial (0% vs 16%, P = 0.08). No change in other health outcomes was observed. Conclusions Oral PR supplementation has a small but significant effect on GM in healthy dogs. Findings warrant further investigation with longer duration in populations at a higher risk of gastrointestinal diseases. Funding Sources NomNomNow Inc.


2011 ◽  
Vol 57 (3) ◽  
pp. 207-211
Author(s):  
Yoni Gavish

In their rebuttal to my comment, Roll et al. (2011) defend their original conclusion, by questioning the theoretical framework on which I based my analysis. They stress the importance of the statistical prediction limits and the treatment of latitudinal location as a covariate. They also add an additional grid-cell-based analysis. Here, I claim that even if provincial species-area relationships (SPAR) are not parallel, they are still different. While relying on Roll et al.'s (2011) analyses, I show that for each taxon there is at least one other provincial SPAR that lies considerably above the Palaearctic SPAR, making Palaearctic countries less favorable to be identified as a global biodiversity hotspot. I further claim that prediction limits should not be used to answer the question in focus and that adding latitude as a covariate does not alter the results. Finally, I address the grid-cell analyses of Roll et al. (2011), claiming that Israel's diversity lies mainly in the species turnover between cells (i.e., β diversity) and not on the average species richness within cells (α diversity). Therefore I hold on to my former conclusion that at least for three taxa—birds, mammals, and reptiles—Israel is indeed a Palaearctic provincial hotspot.


Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1984
Author(s):  
Anthi Oikonomou ◽  
Konstantinos Stefanidis

Disentangling the main drivers of species richness and community composition is a central theme in ecology. Freshwater biodiversity patterns have been poorly explored; yet, it has been shown that different freshwater biota have different, often contrasting responses to environmental gradients. In this study, we investigated the relative contribution of geographical and environmental (habitat-, climate- and water quality-related) factors/gradients in shaping the α- and β-diversity patterns of macrophytes and fish in sixteen natural freshwater lakes of an unexplored Balkan biodiversity hotspot, the Southern Balkan Peninsula. We employed generalized linear modeling to identify drivers of α-diversity, and generalized dissimilarity modeling to explore commonalities and dissimilarities of among-biota β-diversity. Species richness of both biota was significantly associated with lake surface area, whereas macrophytes had an inverse response to altitude, compared to fish. Both species turnover and nestedness significantly contributed to the total β-diversity of macrophytes. In contrast, species turnover was the most significant contributor to the total fish β-diversity. We found that the compositional variation of macrophytes is primarily limited by dispersal and ultimately shaped by environmental drivers, resulting in spatially structured assemblages. Fish communities were primarily shaped by altitude, highlighting the role of species sorting. We conclude that among-biota diversity patterns are shaped by different/contrasting factors, and, thus, effective/sustainable conservation strategies should encompass multiple aquatic biota.


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