Our knowledge of species and functional composition of the human gut microbiome is rapidly increasing, but it is still based on very few cohorts and little is known about variation across the world. By combining 22 newly sequenced faecal metagenomes of individuals from four countries with previously published data sets, here we identify three robust clusters (referred to as enterotypes hereafter) that are not nation or continent specific. We also confirmed the enterotypes in two published, larger cohorts, indicating that intestinal microbiota variation is generally stratified, not continuous. This indicates further the existence of a limited number of well-balanced host-microbial symbiotic states that might respond differently to diet and drug intake. The enterotypes are mostly driven by species composition, but abundant molecular functions are not necessarily provided by abundant species, highlighting the importance of a functional analysis to understand microbial communities. Although individual host properties such as body mass index, age, or gender cannot explain the observed enterotypes, data-driven marker genes or functional modules can be identified for each of these host properties. For example, twelve genes significantly correlate with age and three functional modules with the body mass index, hinting at a diagnostic potential of microbial markers.

/pdf/enterotypes-of-the-human-gut-microbiome-55a88sj7we.pdf

Enterotypes of the human gut microbiome

Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. To carry out analysis on gut microbial content in patients with type 2 diabetes, we developed a protocol for a metagenome-wide association study (MGWAS) and undertook a two-stage MGWAS based on deep shotgun sequencing of the gut microbial DNA from 345 Chinese individuals. We identified and validated approximately 60,000 type-2-diabetes-associated markers and established the concept of a metagenomic linkage group, enabling taxonomic species-level analyses. MGWAS analysis showed that patients with type 2 diabetes were characterized by a moderate degree of gut microbial dysbiosis, a decrease in the abundance of some universal butyrate-producing bacteria and an increase in various opportunistic pathogens, as well as an enrichment of other microbial functions conferring sulphate reduction and oxidative stress resistance. An analysis of 23 additional individuals demonstrated that these gut microbial markers might be useful for classifying type 2 diabetes.

/pdf/a-metagenome-wide-association-study-of-gut-microbiota-in-4gng2ouuna.pdf

A metagenome-wide association study of gut microbiota in type 2 diabetes

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for "consolidated bioprocessing" (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

/pdf/microbial-cellulose-utilization-fundamentals-and-4yec12qx1c.pdf

Microbial cellulose utilization: fundamentals and biotechnology.

Trillions of microbes inhabit the human intestine, forming a complex ecological community that influences normal physiology and susceptibility to disease through its collective metabolic activities and host interactions. Understanding the factors that underlie changes in the composition and function of the gut microbiota will aid in the design of therapies that target it. This goal is formidable. The gut microbiota is immensely diverse, varies between individuals and can fluctuate over time — especially during disease and early development. Viewing the microbiota from an ecological perspective could provide insight into how to promote health by targeting this microbial community in clinical treatments.

/pdf/diversity-stability-and-resilience-of-the-human-gut-2sktyw2s6e.pdf

Diversity, stability and resilience of the human gut microbiota

Recently, substantial advances in the understanding of the molecular pathogenesis of inflammatory bowel disease (IBD) have been made owing to three related lines of investigation. First, IBD has been found to be the most tractable of complex disorders for discovering susceptibility genes, and these have shown the importance of epithelial barrier function, and innate and adaptive immunity in disease pathogenesis. Second, efforts directed towards the identification of environmental factors implicate commensal bacteria (or their products), rather than conventional pathogens, as drivers of dysregulated immunity and IBD. Third, murine models, which exhibit many of the features of ulcerative colitis and seem to be bacteria-driven, have helped unravel the pathogenesis/mucosal immunopathology of IBD.

Unravelling the pathogenesis of inflammatory bowel disease

The present invention relates to a method for diagnosing vaginal infections and for evaluating the efficacy of treatment of vaginal infection detecting the presence or absence of one or more vaginal bacteria in a vaginal fluid sample. The method is also useful for evaluating the relapse after the end of antibiotic treatment.

Identification of vaginal bacteria

Respiratory tract infections (RTIs) are common in childhood and represent one of the main causes of hospitalization in this population. In recent years, many studies have described the association between gut microbiota (GM) composition and RTIs in animal models. In particular, the “inter-talk” between GM and the immune system has recently been unveiled. However, the role of GM in human, and especially infantile, RTIs has not yet been fully established. In this narrative review we provide an up-to-date overview of the physiological pathways that explain how the GM shapes the immune system, potentially influencing the response to common childhood respiratory viral infections and compare studies analysing the relationship between GM composition and RTIs in children. Most studies provide evidence of GM dysbiosis, but it is not yet possible to identify a distinct bacterial signature associated with RTI predisposition. A better understanding of GM involvement in RTIs could lead to innovative integrated GM-based strategies for the prevention and treatment of RTIs in the paediatric population.

/pdf/the-relationship-between-gut-microbiota-and-respiratory-1c1hirsw.pdf

The Relationship between Gut Microbiota and Respiratory Tract Infections in Childhood: A Narrative Review

A short series of N-monosubstituted (aryl, aminoacyl, dipeptidyl)-2-(2-aminothiazol-4-yl)-(Z) -2-methoxyiminoacetamides was synthesized and tested for antimicrobial activity. A few members showed a somewhat interesting inhibitory action against Cryptococcus neoformans (MIC = 150 micrograms/ml).

Synthesis and antimicrobial activity of some N-monosubstituted 2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamides.

Aims: The bacteria‐host molecular cross-talk is the matter of primary importance both in pathogenesis and in commensalism. Principally based on immunological methods, the methodologies commonly utilized for these studies are laborious and require specific antibodies. Here, we developed a new highperformance affinity chromatography (HPAC)-based approach that allows a direct measure of the interaction between whole bacterial cells and host molecules. Methods and Results: Bifidobacterium lactis BI07 cells immobilized on aminoderivatized silica beads were utilized as stationary phase in a high-performance affinity chromatography approach. The analytes plasminogen, collagen I and collagen IV were injected, and interactions were evaluated by the insertion in an HPLC system with UV detection. According to our data, Bif. lactis BI07 is capable of interacting with plasminogen, while it does not exhibit any binding activity to collagen I and IV. Conclusions: In this study, we implemented a high-performance affinity chromatography-based method to characterize the biological interaction between whole micro-organisms and target proteins. Significance and Impact of the Study: With respect to the approaches commonly utilized to study the interaction between bacteria and host proteins, this HPAC-based approach is fast and cheaper than other methods and allows a direct measure of the interaction between bacterial cells and target molecules. Letters in Applied Microbiology ISSN 0266-8254

https://sfamjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1472-765X.2010.02953.x

Development of a high-performance affinity chromatography-based method to study the biological interaction between whole micro-organisms and target proteins.

Patrizia Brigidi

Papers

Identification of vaginal bacteria

The Relationship between Gut Microbiota and Respiratory Tract Infections in Childhood: A Narrative Review

Synthesis and antimicrobial activity of some N-monosubstituted 2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamides.

Development of a high-performance affinity chromatography-based method to study the biological interaction between whole micro-organisms and target proteins.

[Amidine derivatives of 9H-fluorene].