scholarly journals Multi-Method Characterisation of the Human Circulating Microbiome

2018 ◽  
Author(s):  
E. Whittle ◽  
M.O. Leonard ◽  
R. Harrison ◽  
T.W. Gant ◽  
D.P Tonge

AbstractThe term microbiome describes the genetic material encoding the various microbial populations that inhabit our body. Whilst colonisation of various body niches (e.g. the gut) by dynamic communities of microorganisms is now universally accepted, the existence of microbial populations in other “classically sterile” locations, including the blood, is a relatively new concept. The presence of bacteria-specific DNA in the blood has been reported in the literature for some time, yet the true origin of this is still the subject of much deliberation. The aim of this study was to investigate the phenomenon of a “blood microbiome” by providing a comprehensive description of bacterially-derived nucleic acids using a range of complementary molecular and classical microbiological techniques. For this purpose we utilised a set of plasma samples from healthy subjects (n = 5) and asthmatic subjects (n = 5). DNA-level analyses involved the amplification and sequencing of the 16S rRNA gene. RNA-level analyses were based upon thede novoassembly of unmapped mRNA reads and subsequent taxonomic identification. Molecular studies were complemented by viability data from classical aerobic and anaerobic microbial culture experiments. At the phylum level, the blood microbiome was predominated by Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes. The key phyla detected were consistent irrespective of molecular method (DNA vs RNA), and consistent with the results of other published studies.In silicocomparison of our data with that of the Human Microbiome Project revealed that members of the blood microbiome were most likely to have originated from the oral or skin communities. To our surprise, aerobic and anaerobic cultures were positive in eight of out the ten donor samples investigated, and we reflect upon their source. Our data provide further evidence of a core blood microbiome, and provide insight into the potential source of the bacterial DNA / RNA detected in the blood. Further, data reveal the importance of robust experimental procedures, and identify areas for future consideration.

2017 ◽  
Author(s):  
Victoria Cepeda ◽  
Bo Liu ◽  
Mathieu Almeida ◽  
Christopher M. Hill ◽  
Sergey Koren ◽  
...  

ABSTRACTMetagenomic studies have primarily relied on de novo approaches for reconstructing genes and genomes from microbial mixtures. While database driven approaches have been employed in certain analyses, they have not been used in the assembly of metagenomes. Here we describe the first effective approach for reference-guided metagenomic assembly of low-abundance bacterial genomes that can complement and improve upon de novo metagenomic assembly methods. When combined with de novo assembly approaches, we show that MetaCompass can generate more complete assemblies than can be obtained by de novo assembly alone, and improve on assemblies from the Human Microbiome Project (over 2,000 samples).


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Chang Liu ◽  
Meng-Xuan Du ◽  
Rexiding Abuduaini ◽  
Hai-Ying Yu ◽  
Dan-Hua Li ◽  
...  

Abstract Background In gut microbiome studies, the cultured gut microbial resource plays essential roles, such as helping to unravel gut microbial functions and host-microbe interactions. Although several major studies have been performed to elucidate the cultured human gut microbiota, up to 70% of the Unified Human Gastrointestinal Genome species have not been cultured to date. Large-scale gut microbial isolation and identification as well as availability to the public are imperative for gut microbial studies and further characterizing human gut microbial functions. Results In this study, we constructed a human Gut Microbial Biobank (hGMB; homepage: hgmb.nmdc.cn) through the cultivation of 10,558 isolates from 31 sample mixtures of 239 fresh fecal samples from healthy Chinese volunteers, and deposited 1170 strains representing 400 different species in culture collections of the International Depository Authority for long-term preservation and public access worldwide. Following the rules of the International Code of Nomenclature of Prokaryotes, 102 new species were characterized and denominated, while 28 new genera and 3 new families were proposed. hGMB represented over 80% of the common and dominant human gut microbial genera and species characterized from global human gut 16S rRNA gene amplicon data (n = 11,647) and cultured 24 “most-wanted” and “medium priority” taxa proposed by the Human Microbiome Project. We in total sequenced 115 genomes representing 102 novel taxa and 13 previously known species. Further in silico analysis revealed that the newly sequenced hGMB genomes represented 22 previously uncultured species in the Unified Human Gastrointestinal Genome (UHGG) and contributed 24 representatives of potentially “dark taxa” that had not been discovered by UHGG. The nonredundant gene catalogs generated from the hGMB genomes covered over 50% of the functionally known genes (KEGG orthologs) in the largest global human gut gene catalogs and approximately 10% of the “most wanted” functionally unknown proteins in the FUnkFams database. Conclusions A publicly accessible human Gut Microbial Biobank (hGMB) was established that contained 1170 strains and represents 400 human gut microbial species. hGMB expands the gut microbial resources and genomic repository by adding 102 novel species, 28 new genera, 3 new families, and 115 new genomes of human gut microbes.


2018 ◽  
Author(s):  
Qianqian Liu ◽  
Feizhou Zhu ◽  
Liyu Chen ◽  
Meihua Xu ◽  
Jianwei Chen ◽  
...  

The microbiota in the human gut is not only a complicated microecological system but also plays important roles in both health and disease. In order to understand the roles of these gut bacteria, we determined the distribution of microbiota in different regions of the gut by sequencing the 16S rRNA gene V4 region of the bacteria in the saliva, gastric juice, and stool of healthy individuals. The 16S rRNA gene V3-V5 region sequences of saliva and stool microbiota were obtained from Human Microbiome Project (HMP) and the V4 sequence was obtained from the V3-V5 sequences by a program designed by Perl language. We found that the microbiota of the gastric juice is more similar to those in the saliva rather than that in the stool. The frequency of some taxa was significantly different among the three groups with the Streptococcus, Veillonella, Oribacterium, Selenomonas, Actinomyces, and Granulicatella most abundant in the saliva; the Prevotella, Neisseria, Actinobacillus, Treponema, and Helicobacter most abundant in the gastric juice; and the Bacteroides, Parabacteroides, Faecalibacterium, Sutterella, Ruminococcus, Oscillospira and Phascolarctobacterium most abundant in the stool. In addition, results from PICRUSt analyses suggest that the functions of microbiota in the gastric juice are more similar as those in the saliva than in the stool. Moreover, we also found that the membrane transport of the microbiota in the saliva is higher than that in the stool and gastric juice. To our knowledge, this is the first comprehensive comparison of microbiota in the human oral cavity, stomach, and intestine.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 103 ◽  
Author(s):  
Subina Mehta ◽  
Marie Crane ◽  
Emma Leith ◽  
Bérénice Batut ◽  
Saskia Hiltemann ◽  
...  

The Human Microbiome Project (HMP) aided in understanding the role of microbial communities and the influence of collective genetic material (the ‘microbiome’) in human health and disease. With the evolution of new sequencing technologies, researchers can now investigate the microbiome and map its influence on human health. Advances in bioinformatics methods for next-generation sequencing (NGS) data analysis have helped researchers to gain an in-depth knowledge about the taxonomic and genetic composition of microbial communities. Metagenomic-based methods have been the most commonly used approaches for microbiome analysis; however, it primarily extracts information about taxonomic composition and genetic potential of the microbiome under study, lacking quantification of the gene products (RNA and proteins). Conversely, metatranscriptomics, the study of a microbial community’s RNA expression, can reveal the dynamic gene expression of individual microbial populations and the community as a whole, ultimately providing information about the active pathways in the microbiome.  In order to address the analysis of NGS data, the ASaiM analysis framework was previously developed and made available via the Galaxy platform. Although developed for both metagenomics and metatranscriptomics, the original publication demonstrated the use of ASaiM only for metagenomics, while thorough testing for metatranscriptomics data was lacking.  In the current study, we have focused on validating and optimizing the tools within ASaiM for metatranscriptomics data. As a result, we deliver a robust workflow that will enable researchers to understand dynamic functional response of the microbiome in a wide variety of metatranscriptomics studies. This improved and optimized ASaiM-metatranscriptomics (ASaiM-MT) workflow is publicly available via the ASaiM framework, documented and supported with training material so that users can interrogate and characterize metatranscriptomic data, as part of larger meta-omic studies of microbiomes.


2015 ◽  
Author(s):  
Martial Marbouty ◽  
Lyam Baudry ◽  
Axel Cournac ◽  
Romain Koszul

Microbial populations as well as they biochemical activities are important components of environmental ecosystems, including the human microbiome. Deciphering the genomic content of these complex mixes of species is an important challenge but is essential to fully understand the regulation of their ecological balance. Here we apply meta3C, an experimental and computational approach that exploits the physical contacts between chromosomes to characterize large genomic regions of bacterial species mixed together, on a truly complex ecosystem: the mouse gut microbiota. Meta3C, which was initially described and applied onto controlled mixes of microorganisms, allowed the de novo assembly and scaffolding of numerous bacteria present into this natural mix. Importantly, the scaffolds analyzed exhibit the structural properties expected from typical bacterial chromosomes. Meta3C therefore paves the way to the in-depth analysis of genomic structuration of complex populations.


Author(s):  
Chang Liu ◽  
Meng-Xuan Du ◽  
Rexiding Abuduaini ◽  
Hai-Ying Yu ◽  
Dan-Hua Li ◽  
...  

Abstract Background The cultivated gut microbial resource plays essential role in gut microbiome studies such as gut microbial function and their interactions with host. Though several major studies had been performed to understand the cultured human gut microbiota, up to 70% of the Unified Human Gastrointestinal Genome species remain uncultivated and their taxonomy is not clear. Large-scale gut microbial isolation and identification and their access to pubic are imperative for gut microbial studies and for understanding of the human gut microbial functions.Results Here, we report the construction of an human Gut Microbial Biobank (hGMB) (homepage: hgmb.nmdc.cn) by large-scale cultivation of 10,558 isolates from 239 feces of healthy Chinese volunteers, and deposited 1,170 strains representing 404 different species in International Depository Authority for long-term preservation and public access worldwidely. We discovered and denominated 107 new species, and proposed 28 new genera and 3 new families. The new species and their newly sequenced genomes uncovered 16 “most-wanted” or “medium priority” taxa proposed by the Human Microbiome Project and 42 previously-uncultured MAGs in IGGdb, respectively. The hGMB represented over 80% of the common and dominant human gut microbial genera or species of global human gut 16S rRNA gene amplicon data (n=11,647), and covered 70% of the known genes (KEGG Orthologys) and 10% of the functionally-unknown genes in the global human gut gene catalogs. Conclusions A publically accessible human Gut Microbial Biobank (hGMB) that contains 1,170 strains and represents 404 human gut microbial speces is estabolished. The hGMB expands the currently known, taxonomically-characterized gut microbial resources and genomic repository by adding 107 new species and 115 new genomes of human gut microbes. Based on the newly discovered species in this study, 28 new genera and 3 new families of human gut microbes were identified and proposed.


2021 ◽  
Author(s):  
Yunxi Liu ◽  
R. A. Leo Elworth ◽  
Michael D. Jochum ◽  
Kjersti M. Aagaard ◽  
Todd J. Treangen

Computational analysis of host-associated microbiomes has opened the door to numerous discoveries relevant to human health and disease. However, contaminant sequences in metagenomic samples can potentially impact the interpretation of findings reported in microbiome studies, especially in low biomass environments. Our hypothesis is that contamination from DNA extraction kits or sampling lab environments will leave taxonomic bread crumbs across multiple distinct sample types, allowing for the detection of microbial contaminants when negative controls are unavailable. To test this hypothesis we implemented Squeegee, a de novo contamination detection tool. We tested Squeegee on simulated and real low biomass metagenomic datasets. On the low biomass samples, we compared Squeegee predictions to experimental negative control data and show that Squeegee accurately recovers known contaminants. We also analyzed 749 metagenomic datasets from the Human Microbiome Project and identified likely previously unreported kit contamination. Collectively, our results highlight that Squeegee can identify microbial contaminants with high precision. Squeegee is open-source and available at: https://gitlab.com/treangenlab/squeegee


2021 ◽  
Author(s):  
Chang Liu ◽  
Mengxuan Du ◽  
Rexiding Abuduaini ◽  
Hai-Ying Yu ◽  
Dan-Hua Li ◽  
...  

Abstract BackgroundThe cultivated gut microbial resource plays essential roles in gut microbiome studies such as unraveling gut microbial functions and host-microbe interactions. Though several major studies have been performed to understand the cultured human gut microbiota, up to 70% of the Unified Human Gastrointestinal Genome species remain uncultivated. Large-scale gut microbial isolation and identification and their access to public are imperative for gut microbial studies and further understanding of the human gut microbial functions.ResultsHere, we report the construction of a human Gut Microbial Biobank (hGMB) (homepage: hgmb.nmdc.cn) by cultivation of 10,558 isolates from 239 feces samples of healthy Chinese volunteers, and deposited 1,170 strains representing 400 different species in culture collections of International Depository Authority for long-term preservation and public access worldwide. The hGMB enriched the existing cultivable gut microbial repository and represented over 80% of the common and dominant human gut microbial genera and species of global human gut 16S rRNA gene amplicon data (n=11,647).Moreover, 102 new species were characterized and denominated and 28 new genera and 3 new families were proposed, following the rules of International Code of Nomenclature of Prokaryotes. The hGMB uncovered 24 “most-wanted” and “medium priority” taxa proposed by the Human Microbiome Project, while the novel-taxon genomes represented 22 previously-uncultured species in Unified Human Gastrointestinal Genome (UHGG) and contributed 24 potentially “dark-taxon” representatives that were not discovered by UHGG. The 115 newly-sequenced hGMB genomes covered over 50% of the known genes (KEGG Orthologs) in the global human gut gene catalogs and over 10% of the “most-wanted” functionally unknown proteins in FUnkFams database.ConclusionsA publicly accessible human Gut Microbial Biobank (hGMB) is established and contains 1,170 strains and represents 400 human gut microbial species. The hGMB expands gut microbial resources and genomic repository by adding 102 novel species, 28 new genera and 3 new families, and 115 new genomes of human gut microbes.


2019 ◽  
Author(s):  
Zhuye Jie ◽  
Chen Chen ◽  
Lilan Hao ◽  
Fei Li ◽  
Liu Tian ◽  
...  

The gut microbiome has been the center of attention for human commensal microbiome studies. The vaginal microbiome is also densely populated with bacteria, viruses and fungi, and the presence of microorganisms beyond the cervix is increasingly reported in non-infectious conditions1–3. Due to the over 90% of human sequences in female reproductive tract samples3,4, metagenomic information has been very limited. 16S rRNA gene amplicon sequencing studies have identified community types in the vaginal microbiota, and observed its dynamic changes due to menstrual cycles and sexual behaviors in small cohorts5,6. Here we perform metagenomic shotgun sequencing on cervical samples from 516 women of reproductive age (more than 10-fold of the Human Microbiome Project (HMP)4), and dissect major factors, especially pregnancy and delivery histories and contraception methods on the microbiome composition. Features of other body sites, such as mood fluctuations and facial speckles could potentially be deduced from the vagino-cervical microbiome. Our results offer an unprecedented glimpse into the microbiota in the female reproductive tract and imply disease susceptibilities that may be relieved by behavioural changes.


mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Bruce A. Rosa ◽  
Kathie Mihindukulasuriya ◽  
Kymberlie Hallsworth-Pepin ◽  
Aye Wollam ◽  
John Martin ◽  
...  

ABSTRACT Whole-genome bacterial sequences are required to better understand microbial functions, niche-specific bacterial metabolism, and disease states. Although genomic sequences are available for many of the human-associated bacteria from commonly tested body habitats (e.g., feces), as few as 13% of bacterium-derived reads from other sites such as the skin map to known bacterial genomes. To facilitate a better characterization of metagenomic shotgun reads from underrepresented body sites, we collected over 10,000 bacterial isolates originating from 14 human body habitats, identified novel taxonomic groups based on full-length 16S rRNA gene sequences, clustered the sequences to ensure that no individual taxonomic group was overselected for sequencing, prioritized bacteria from underrepresented body sites (such as skin and respiratory and urinary tracts), and sequenced and assembled genomes for 665 new bacterial strains. Here, we show that addition of these genomes improved read mapping rates of Human Microbiome Project (HMP) metagenomic samples by nearly 30% for the previously underrepresented phylum Fusobacteria, and 27.5% of the novel genomes generated here had high representation in at least one of the tested HMP samples, compared to 12.5% of the sequences in the public databases, indicating an enrichment of useful novel genomic sequences resulting from the prioritization procedure. As our understanding of the human microbiome continues to improve and to enter the realm of therapy developments, targeted approaches such as this to improve genomic databases will increase in importance from both an academic and a clinical perspective. IMPORTANCE The human microbiome plays a critically important role in health and disease, but current understanding of the mechanisms underlying the interactions between the varying microbiome and the different host environments is lacking. Having access to a database of fully sequenced bacterial genomes provides invaluable insights into microbial functions, but currently sequenced genomes for the human microbiome have largely come from a limited number of body sites (primarily feces), while other sites such as the skin, respiratory tract, and urinary tract are underrepresented, resulting in as little as 13% of bacterium-derived reads mapping to known bacterial genomes. Here, we sequenced and assembled 665 new bacterial genomes, prioritized from a larger database to select underrepresented body sites and bacterial taxa in the existing databases. As a result, we substantially improve mapping rates for samples from the Human Microbiome Project and provide an important contribution to human bacterial genomic databases for future studies.


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