scholarly journals Probiotic Bacteria Influence the Composition and Function of the Intestinal Microbiota

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Paul W. O'Toole ◽  
Jakki C. Cooney
Keyword(s):  
Intestinal Microbiota ◽  
Bacterial Species ◽  
Analytical Techniques ◽  
Probiotic Bacteria ◽  
Mediated Effects ◽  
Molecular Approaches ◽  
Human Intestinal Microbiota ◽  
Altered Immune Response ◽  
And Function

Probiotics have a range of proposed health benefits for the consumer, which may include modulating the levels of beneficial elements in the microbiota. Recent investigations using molecular approaches have revealed a human intestinal microbiota comprising over 1000 phylotypes. Mechanisms whereby probiotics impact on the intestinal microbiota include competition for substrates, direct antagonism by inhibitory substances, competitive exclusion, and potentially host-mediated effects such as improved barrier function and altered immune response. We now have the microbial inventories and genetic blueprints to begin tackling intestinal microbial ecology at an unprecedented level of detail, aided by the understanding that dietary components may be utilized differentially by individual phylotypes. Controlled intervention studies in humans, utilizing latest molecular technologies, are required to consolidate evidence for bacterial species that impact on the microbiota. Mechanistic insights should be provided by metabolomics and other analytical techniques for small molecules. Rigorous characterization of interactions between the diet, microbiota, and probiotic bacteria will provide new opportunities for modulating the microbiota towards improving human health.

scholarly journals Discovery of novel community-relevant small proteins in a simplified human intestinal microbiome

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannes Petruschke ◽  
Christian Schori ◽  
Sebastian Canzler ◽  
Sarah Riesbeck ◽  
Anja Poehlein ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Intestinal Microbiota ◽  
De Novo ◽  
Bacterial Species ◽  
Intestinal Microbiome ◽  
Single Strain ◽  
Small Proteins ◽  
Human Intestinal Microbiota ◽  
Wide Range

Abstract Background The intestinal microbiota plays a crucial role in protecting the host from pathogenic microbes, modulating immunity and regulating metabolic processes. We studied the simplified human intestinal microbiota (SIHUMIx) consisting of eight bacterial species with a particular focus on the discovery of novel small proteins with less than 100 amino acids (= sProteins), some of which may contribute to shape the simplified human intestinal microbiota. Although sProteins carry out a wide range of important functions, they are still often missed in genome annotations, and little is known about their structure and function in individual microbes and especially in microbial communities. Results We created a multi-species integrated proteogenomics search database (iPtgxDB) to enable a comprehensive identification of novel sProteins. Six of the eight SIHUMIx species, for which no complete genomes were available, were sequenced and de novo assembled. Several proteomics approaches including two earlier optimized sProtein enrichment strategies were applied to specifically increase the chances for novel sProtein discovery. The search of tandem mass spectrometry (MS/MS) data against the multi-species iPtgxDB enabled the identification of 31 novel sProteins, of which the expression of 30 was supported by metatranscriptomics data. Using synthetic peptides, we were able to validate the expression of 25 novel sProteins. The comparison of sProtein expression in each single strain versus a multi-species community cultivation showed that six of these sProteins were only identified in the SIHUMIx community indicating a potentially important role of sProteins in the organization of microbial communities. Two of these novel sProteins have a potential antimicrobial function. Metabolic modelling revealed that a third sProtein is located in a genomic region encoding several enzymes relevant for the community metabolism within SIHUMIx. Conclusions We outline an integrated experimental and bioinformatics workflow for the discovery of novel sProteins in a simplified intestinal model system that can be generically applied to other microbial communities. The further analysis of novel sProteins uniquely expressed in the SIHUMIx multi-species community is expected to enable new insights into the role of sProteins on the functionality of bacterial communities such as those of the human intestinal tract.

scholarly journals Changes in Composition and Function of Human Intestinal Microbiota Exposed to Chlorpyrifos in Oil as Assessed by the SHIME® Model

2016 ◽  
Vol 13 (11) ◽  
pp. 1088 ◽  
Author(s):  
Julie Reygner ◽  
Claire Joly Condette ◽  
Aurélia Bruneau ◽  
Stéphane Delanaud ◽  
Larbi Rhazi ◽  
...  
Keyword(s):  
Intestinal Microbiota ◽  
Human Intestinal Microbiota ◽  
And Function

scholarly journals Recent advances in the characterization of Crl, the unconventional activator of the stress sigma factor σS/RpoS

2016 ◽  
Vol 7 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Paola Cavaliere ◽  
Françoise Norel
Keyword(s):  
Transcription Initiation ◽  
Current Knowledge ◽  
Bacterial Species ◽  
Adaptive Responses ◽  
Active Growth ◽  
Recent Advances ◽  
Serovar Typhimurium ◽  
Σ Factor ◽  
And Function

AbstractThe bacterial RNA polymerase (RNAP) holoenzyme is a multisubunit core enzyme associated with a σ factor that is required for promoter-specific transcription initiation. Besides a primary σ responsible for most of the gene expression during active growth, bacteria contain alternative σ factors that control adaptive responses. A recurring strategy in the control of σ factor activity is their sequestration by anti-sigma factors that occlude the RNAP binding determinants, reducing their activity. In contrast, the unconventional transcription factor Crl binds specifically to the alternative σ factor σS/RpoS, and favors its association with the core RNAP, thereby increasing its activity. σS is the master regulator of the general stress response that protects many Gram-negative bacteria from several harmful environmental conditions. It is also required for biofilm formation and virulence of Salmonella enterica serovar Typhimurium. In this report, we discuss current knowledge on the regulation and function of Crl in Salmonella and Escherichia coli, two bacterial species in which Crl has been studied. We review recent advances in the structural characterization of the Crl-σS interaction that have led to a better understanding of this unusual mechanism of σ regulation.

Characterization of high molecular weight coffee fractions and their fermentation by human intestinal microbiota

2009 ◽  
Vol 53 (2) ◽  
pp. 287-299 ◽  
Author(s):  
Nicole Reichardt ◽  
Diana Gniechwitz ◽  
Hans Steinhart ◽  
Mirko Bunzel ◽  
Michael Blaut
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Intestinal Microbiota ◽  
Human Intestinal Microbiota

Approaches and developments in studying the human microbiome network

2015 ◽  
Vol 61 (2) ◽  
pp. 90-94 ◽  
Author(s):  
Mor Nitzan ◽  
Sefi Mintzer ◽  
Hanah Margalit
Keyword(s):  
Bacterial Population ◽  
Bacterial Species ◽  
Human Microbiome ◽  
Structure And Function ◽  
Complex Relationship ◽  
Human Host ◽  
Competition And Cooperation ◽  
Health And Disease ◽  
And Function

The human microbiome is dynamic and unique to each individual, and its role is being increasingly recognized in healthy physiology and in disease, including gastrointestinal and neuropsychiatric disorders. Therefore, characterizing the human microbiome and the factors that shape its bacterial population, how they are related to host-specific attributes, and understanding the ways in which it can be manipulated and the phenotypic consequences of such manipulations are of great importance. Characterization of the microbiome so far has been mostly based on compositional studies alone, where relative abundances of different species are compared in different conditions, such as health and disease. However, inter-relationships among the bacterial species, such as competition and cooperation over metabolic resources, may be an important factor that affects the structure and function of the microbiome. Here we review the network-based approaches in answering such questions and explore the first attempts that focus on the interactions facet, complementing compositional studies, towards understanding the microbiome structure and its complex relationship with the human host.

scholarly journals Metagenomic Characterization of the Human Intestinal Microbiota in Fecal Samples from STEC-Infected Patients

2018 ◽  
Vol 8 ◽  
Author(s):  
Federica Gigliucci ◽  
F. A. Bastiaan von Meijenfeldt ◽  
Arnold Knijn ◽  
Valeria Michelacci ◽  
Gaia Scavia ◽  
...  
Keyword(s):  
Intestinal Microbiota ◽  
Fecal Samples ◽  
Human Intestinal Microbiota

scholarly journals Human intestinal microbiota: Characterization of a simplified and stable gnotobiotic rat model

Gut Microbes ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Natalie Becker ◽  
Julia Kunath ◽  
Gunnar Loh ◽  
Michael Blaut
Keyword(s):  
Intestinal Microbiota ◽  
Rat Model ◽  
Human Intestinal Microbiota

scholarly journals Modulation of Anti-Tumour Immune Responses by Probiotic Bacteria

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 329 ◽  
Author(s):  
Georgios Aindelis ◽  
Katerina Chlichlia
Keyword(s):  
Immune Responses ◽  
Intestinal Microbiota ◽  
Current Knowledge ◽  
Human Subjects ◽  
Bacterial Species ◽  
Probiotic Bacteria ◽  
Response To Treatment ◽  
Malignant Tumours ◽  
Cancer Immunotherapies

There is a growing amount of evidence to support the beneficial role of a balanced intestinal microbiota, or distinct members thereof, in the manifestation and progression of malignant tumours, not only in the gastrointestinal tract but also in distant tissues as well. Intriguingly, bacterial species have been demonstrated to be indispensable modulatory agents of widely-used immunotherapeutic or chemotherapeutic regiments. However, the exact contribution of commensal bacteria to immunity, as well as to neoplasia formation and response to treatment, has not been fully elucidated, and most of the current knowledge acquired from animal models has yet to be translated to human subjects. Here, recent advances in understanding the interaction of gut microbes with the immune system and the modulation of protective immune responses to cancer, either naturally or in the context of widely-used treatments, are reviewed, along with the implications of these observations for future therapeutic approaches. In this regard, bacterial species capable of facilitating optimal immune responses against cancer have been surveyed. According to the findings summarized here, we suggest that strategies incorporating probiotic bacteria and/or modulation of the intestinal microbiota can be used as immune adjuvants, aiming to optimize the efficacy of cancer immunotherapies and conventional anti-tumour treatments.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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