scholarly journals Functional and taxonomic comparison of mouse and human gut microbiotas using extensive culturing and metagenomics

Author(s):  
Benjamin S. Beresford-Jones ◽  
Samuel C. Forster ◽  
Mark D. Stares ◽  
George Notley ◽  
Elisa Viciani ◽  
...  

AbstractMouse models are essential for biomedical science and drug discovery, yet it is not known how the bacteria in the mouse microbiota – important determinants of phenotypes of health and disease –affect their relevance to human disease. To interrogate the taxonomic and functional differences between the human and mouse gut microbiotas, we developed the Mouse Microbial Genome Collection (MMGC), a compilation of 276 genomes from cultured isolates and 45,218 metagenome-assembled genomes (MAGs) from 1,960 publicly available mouse metagenomes. The MMGC reveals that while only 2.65% of bacterial species are shared between mouse and human, over 80% of annotatable functions are present in both microbiomes. Using drug metabolism and butyrate synthesis as examples, we illustrate that although the species harbouring these key functions can differ between hosts, the MMGC enables identification of functionally equivalent taxa in the mouse and human microbiotas. The MMGC thereby facilitates the informed use of mice in biomedical research by providing access to the conservation and taxonomic locations of bacterial functions of interest.

Metabolites ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Yao Lu ◽  
Jasmine Chong ◽  
Shiqian Shen ◽  
Joey-Bahige Chammas ◽  
Lorraine Chalifour ◽  
...  

Crosstalk between the gut microbiome and the host plays an important role in animal development and health. Small compounds are key mediators in this host–gut microbiome dialogue. For instance, tryptophan metabolites, generated by biotransformation of tryptophan through complex host–microbiome co-metabolism can trigger immune, metabolic, and neuronal effects at local and distant sites. However, the origin of tryptophan metabolites and the underlying tryptophan metabolic pathway(s) are not well characterized in the current literature. A large number of the microbial contributors of tryptophan metabolism remain unknown, and there is a growing interest in predicting tryptophan metabolites for a given microbiome. Here, we introduce TrpNet, a comprehensive database and analytics platform dedicated to tryptophan metabolism within the context of host (human and mouse) and gut microbiome interactions. TrpNet contains data on tryptophan metabolism involving 130 reactions, 108 metabolites and 91 enzymes across 1246 human gut bacterial species and 88 mouse gut bacterial species. Users can browse, search, and highlight the tryptophan metabolic pathway, as well as predict tryptophan metabolites on the basis of a given taxonomy profile using a Bayesian logistic regression model. We validated our approach using two gut microbiome metabolomics studies and demonstrated that TrpNet was able to better predict alterations in in indole derivatives compared to other established methods.


2021 ◽  
Author(s):  
Samuel C. Forster ◽  
Simon Clare ◽  
Benjamin S. Beresford-Jones ◽  
Katherine Harcourt ◽  
George Notley ◽  
...  

The mammalian gut microbiota consists of hundreds of anaerobic bacterial species that shape intestinal homeostasis and influence host immune responses. Although the causal roles of specific human gut bacterial species in health and disease are emerging, the role of indigenous gut bacteria in driving immunophenotypic variability in mouse models of human disease remains poorly understood. We performed a large-scale experiment using 579 laboratory mice designed to identify and validate the causes of disease variability in the widely used dextran sulphate sodium (DSS) mouse model of inflammatory bowel disease. Using microbiome analysis, coupled with machine learning and targeted anaerobic culturing, we identified and isolated the novel gut pathobiont species Duncaniella muricolitica and Alistipes okayasuensis and fulfilled Koch’s postulates in mice to show that each pathobiont exerts dominant effects in the DSS model leading to variable treatment responses. We show these pathobiont species are common, but not ubiquitous, in mouse facilities around the world, raising experimental design opportunities for improved mouse models of human intestinal diseases.


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.


2019 ◽  
Vol 16 (4) ◽  
pp. 386-391 ◽  
Author(s):  
Kenneth Lundstrom

Epigenetic mechanisms comprising of DNA methylation, histone modifications and gene silencing by RNA interference have been strongly linked to the development and progression of various diseases. These findings have triggered research on epigenetic functions and signal pathways as targets for novel drug discovery. Dietary intake has also presented significant influence on human health and disease development and nutritional modifications have proven important in prevention, but also the treatment of disease. Moreover, a strong link between nutrition and epigenetic changes has been established. Therefore, in attempts to develop novel safer and more efficacious drugs, both nutritional requirements and epigenetic mechanisms need to be addressed.


2021 ◽  
Vol 9 (5) ◽  
pp. 1062
Author(s):  
Chunye Zhang ◽  
Craig L. Franklin ◽  
Aaron C. Ericsson

The gut microbiome (GM), a complex community of bacteria, viruses, protozoa, and fungi located in the gut of humans and animals, plays significant roles in host health and disease. Animal models are widely used to investigate human diseases in biomedical research and the GM within animal models can change due to the impact of many factors, such as the vendor, husbandry, and environment. Notably, variations in GM can contribute to differences in disease model phenotypes, which can result in poor reproducibility in biomedical research. Variation in the gut microbiome can also impact the translatability of animal models. For example, standard lab mice have different pathogen exposure experiences when compared to wild or pet store mice. As humans have antigen experiences that are more similar to the latter, the use of lab mice with more simplified microbiomes may not yield optimally translatable data. Additionally, the literature describes many methods to manipulate the GM and differences between these methods can also result in differing interpretations of outcomes measures. In this review, we focus on the GM as a potential contributor to the poor reproducibility and translatability of mouse models of disease. First, we summarize the important role of GM in host disease and health through different gut–organ axes and the close association between GM and disease susceptibility through colonization resistance, immune response, and metabolic pathways. Then, we focus on the variation in the microbiome in mouse models of disease and address how this variation can potentially impact disease phenotypes and subsequently influence research reproducibility and translatability. We also discuss the variations between genetic substrains as potential factors that cause poor reproducibility via their effects on the microbiome. In addition, we discuss the utility of complex microbiomes in prospective studies and how manipulation of the GM through differing transfer methods can impact model phenotypes. Lastly, we emphasize the need to explore appropriate methods of GM characterization and manipulation.


Author(s):  
Kenneth P. Seastedt ◽  
Nathanael Pruett ◽  
Chuong D. Hoang

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 673
Author(s):  
Alexandra L. Whittaker ◽  
Yifan Liu ◽  
Timothy H. Barker

The Mouse Grimace Scale (MGS) was developed 10 years ago as a method for assessing pain through the characterisation of changes in five facial features or action units. The strength of the technique is that it is proposed to be a measure of spontaneous or non-evoked pain. The time is opportune to map all of the research into the MGS, with a particular focus on the methods used and the technique’s utility across a range of mouse models. A comprehensive scoping review of the academic literature was performed. A total of 48 articles met our inclusion criteria and were included in this review. The MGS has been employed mainly in the evaluation of acute pain, particularly in the pain and neuroscience research fields. There has, however, been use of the technique in a wide range of fields, and based on limited study it does appear to have utility for pain assessment across a spectrum of animal models. Use of the method allows the detection of pain of a longer duration, up to a month post initial insult. There has been less use of the technique using real-time methods and this is an area in need of further research.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
David Pellow ◽  
Alvah Zorea ◽  
Maraike Probst ◽  
Ori Furman ◽  
Arik Segal ◽  
...  

Abstract Background Metagenomic sequencing has led to the identification and assembly of many new bacterial genome sequences. These bacteria often contain plasmids: usually small, circular double-stranded DNA molecules that may transfer across bacterial species and confer antibiotic resistance. These plasmids are generally less studied and understood than their bacterial hosts. Part of the reason for this is insufficient computational tools enabling the analysis of plasmids in metagenomic samples. Results We developed SCAPP (Sequence Contents-Aware Plasmid Peeler)—an algorithm and tool to assemble plasmid sequences from metagenomic sequencing. SCAPP builds on some key ideas from the Recycler algorithm while improving plasmid assemblies by integrating biological knowledge about plasmids. We compared the performance of SCAPP to Recycler and metaplasmidSPAdes on simulated metagenomes, real human gut microbiome samples, and a human gut plasmidome dataset that we generated. We also created plasmidome and metagenome data from the same cow rumen sample and used the parallel sequencing data to create a novel assessment procedure. Overall, SCAPP outperformed Recycler and metaplasmidSPAdes across this wide range of datasets. Conclusions SCAPP is an easy to use Python package that enables the assembly of full plasmid sequences from metagenomic samples. It outperformed existing metagenomic plasmid assemblers in most cases and assembled novel and clinically relevant plasmids in samples we generated such as a human gut plasmidome. SCAPP is open-source software available from: https://github.com/Shamir-Lab/SCAPP.


2020 ◽  
Vol 96 (3) ◽  
Author(s):  
Gavin J Fenske ◽  
Sudeep Ghimire ◽  
Linto Antony ◽  
Jane Christopher-Hennings ◽  
Joy Scaria

ABSTRACT Bacterial communities resident in the hindgut of pigs, have profound impacts on health and disease. Investigations into the pig microbiome have utilized either culture-dependent, or far more commonly, culture-independent techniques using next generation sequencing. We contend that a combination of both approaches generates a more coherent view of microbiome composition. In this study, we surveyed the microbiome of Tamworth breed and feral pigs through the integration high throughput culturing and shotgun metagenomics. A single culture medium was used for culturing. Selective screens were added to the media to increase culture diversity. In total, 46 distinct bacterial species were isolated from the Tamworth and feral samples. Selective screens successfully shifted the diversity of bacteria on agar plates. Tamworth pigs are highly dominated by Bacteroidetes primarily composed of the genus Prevotella whereas feral samples were more diverse with almost equal proportions of Firmicutes and Bacteroidetes. The combination of metagenomics and culture techniques facilitated a greater retrieval of annotated genes than either method alone. The single medium based pig microbiota library we report is a resource to better understand pig gut microbial ecology and function. It allows for assemblage of defined bacterial communities for studies in bioreactors or germfree animal models.


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