Microbial Ecology along the Gastrointestinal Tract

Area of Science:

• Microbiology
• Gastroenterology
• Comparative Physiology

Background:

• The human gastrointestinal (GI) tract hosts a complex ecosystem influenced by environmental and dietary factors.
• Microbial composition and function vary significantly along the GI tract, from the oral cavity to the anus.
• Research has historically prioritized Bacteria, with limited focus on Archaea, Eukarya, and Viruses.

Purpose of the Study:

• To review the composition and function of the human GI tract microbiome across different domains (Bacteria, Archaea, Fungi, Viruses).
• To discuss variations within the healthy human GI tract.
• To compare the human GI tract microbiome with those of common animal models (rats, mice, pigs).

Main Methods:

• Literature review of existing studies on human and animal GI tract microbiomes.
• Comparative analysis of microbial diversity and functional roles.
• Discussion of physiological differences impacting microbiome translation from animal models to humans.

Main Results:

• The GI tract presents diverse conditions selecting for specific microbial communities.
• Significant knowledge gaps exist for non-bacterial members of the GI tract microbiome.
• Animal models (rats, mice, pigs) offer insights but require careful physiological and microbiome comparison for human relevance.

Conclusions:

• Understanding the complete human GI tract microbiome (all domains) is crucial.
• Direct human sample collection challenges necessitate animal model studies.
• Clarifying physiological and microbiome differences is key for translating animal model findings to human health.