Bioscience Chapter Database :: 3635 Chapters Now Online

Chapter category: Gastroenterology

The Commensal Microbiology of the Gastrointestinal Tract

This chapter appears in the following book:

GI Microbiota and Regulation
of the Immune System

Edited by: Gary B. Huffnagle and Mairi C. Noverr
ISBN: 978-0-387-79989-6
» Get more information about this book at landesbioscience.com «

Chapter authors:
Janet M. Manson, Marcus Rauch and Michael S. Gilmore


[+] view image
The gastrointestinal (GI) tract is a dynamic environment and therefore the stability of the commensal community, or microbiota, is under constant challenge. Microscopic observations have revealed that the majority of bacteria present in the GI tract are not detected using standard culturing techniques, however with the application of culture‑independent techniques it has been estimated that between 500 to 1000 bacterial species inhabit the human GI tract. Numerically predominant organisms in the microbiota belong to two eubacterial divisions, the Cytophaga‑Flavobacterium‑Bacteroides (CFB) and the Firmicutes, and fall into three main groups; Clostridium rRNA subcluster XIVa, Clostridium rRNA subcluster IV and Bacteroides. The prevalence and diversity of bacteria in different areas of the GI tract is influenced by the different conditions at these sites and thus the microbiota of the stomach and jejunum varies with that of the large intestine. Additionally, host genotype, age and diet have all been shown to affect microbial diversity in the GI tract. The distal intestine harbours the highest bacterial cell densities for any known ecosystem. Characterizing the species composition of the healthy microbiota may be a key step in identifying bacterial or associated physiological conditions that are present or absent in an unhealthy microbiota.

Janet M. Manson
Department of Ophthalmology, Harvard Medical School; and, Schepens Eye Research Institute

Marcus Rauch
Department of Ophthalmology, Harvard Medical School; and, Schepens Eye Research Institute

Michael S. Gilmore
Department of Ophthalmology, Harvard Medical School; and, Schepens Eye Research Institute

» Access chapter for $19



Additional chapters from this book:

Negative Interactions with the Microbiota: IBD

Charles L. Bevins and Nita H. Salzman

Mucosal surfaces are colonized by a complex microbiota that provides beneficial functions under normal physiological conditions, but is capable of contributing to chronic inflammatory disease in susce...

The “Microflora Hypothesis” of Allergic Disease

Andrew Shreiner, Gary B. Huffnagle and Mairi C. Noverr

Predisposition to allergic disease is a complex function of an individual’s genetic background and, as is the case with multi‑gene traits, environmental factors have important phenotypic consequ...

Overview of Gut Immunology

Katie Lynn Mason, Gary B. Huffnagle, Mairi C. Noverr and John Y. Kao

The gastrointestinal tract (GI tract) plays dual roles in human physiology: digestion and uptake of nutrients and the more daunting task of maintaining immune homeostasis (protecting the body from pot...

Effects of Microbiota on GI Health: Gnotobiotic Research

Robert Doug Wagner

The complex interactions between the GI tract microbiota and the immune system can be simplified for study using gnotobiotic animal models. The importance of cytokines, such as IFN‑γ, TNF&#...

Overview of the Gastrointestinal Microbiota

Vincent B. Young and Thomas M. Schmidt

The community of microbes that inhabits the mammalian intestinal tract exists in a symbiosis with their host. The structure of this community represents the combined effects of selection pressure on t...

The Commensal Microbiology of the Gastrointestinal Tract

Janet M. Manson, Marcus Rauch and Michael S. Gilmore

The gastrointestinal (GI) tract is a dynamic environment and therefore the stability of the commensal community, or microbiota, is under constant challenge. Microscopic observations have revealed that...

Diet, Immunity and Functional Foods

Lesley Hoyles and Jelena Vulevic

Functional foods (specific nutrient and/or food components) should beneficially affect one or more target functions in the body. The use of functional foods as a form of preventive medicine has been t...

Host‑Microbe Symbiosis: The Squid‑Vibrio Association‑A Naturally Occurring, Experimental Model of Animal/Bacterial Partnerships

Margaret McFall-Ngai

Many, if not most, animals have specific symbiotic relationships with bacterial partners. Recent studies suggest that vertebrates create alliances with highly complex consortia of hundreds to thousand...

Host‑Microbe Communication within the GI Tract

Christopher A. Allen and Alfredo G. Torres

The gastrointestinal tract is a biologically diverse and complicated system which carries out essential physiological functions that support human health, while at the same time maintaining itself as ...

Positive Interactions with the Microbiota: Probiotics

Marko Kalliomäki, Seppo Salminen and Erika Isolauri

Rigorous research in the field of probiotics is a fairly new phenomenon although first reports about beneficial effects of specific gut bacteria on human health originated already a century ago. A pre...

The Damage‑Response Framework of Microbial Pathogenesis and Infectious Diseases

Liise-anne Pirofski and Arturo Casadevall

Historical and most currently held views of microbial pathogenesis and virulence are plagued by confusing and imprecise terminology and definitions that require revision and exceptions to accommodate ...


SIGN IN

Email:


Password:


lost password?




[ Home | Authors | Editors | Custom Books | Chapter Reprints | Subscribe | Contact | Biotoons ]