Lecture A6-8, pt2 - the mucosal microbiota: mutualists of the gut

What is the effect of urbanization on microbiota diversity?

Urbanization reduces microbial diversity, leading to a loss of VANISH taxa.

Name one key difference between traditional and industrialized microbiota.

Traditional microbiota are enriched in fiber-degrading taxa like Prevotella, while industrialized microbiota have reduced diversity and are linked to inflammation-related diseases.

How do probiotics support epithelial repair?

Probiotics like Lactobacillus stimulate mucin production and epithelial cell regeneration.

What is a common prebiotic, and how does it work?

Inulin, a non-digestible fiber, promotes the growth of SCFA-producing bacteria like Faecalibacterium prausnitzii.

Why is FMT effective for treating C. difficile infections?

FMT restores microbial diversity and competitive exclusion, preventing C. difficile overgrowth.

How does a high-fiber diet influence microbiota composition?

Increases microbial diversity and supports the growth of beneficial SCFA-producing microbes.

How does diet influence gut microbiota composition?

• High-fiber diets: Enhance diversity and SCFA production.

• Low-fiber, high-protein diets: Increase harmful proteolytic fermentation.

What environmental factors reduce microbiota diversity?

Urbanization and antibiotic use.

What is cross-feeding, and give an example?

When one microbial species metabolizes a substrate and provides by-products for another.

• Example: Bacteroides spp. break down polysaccharides, releasing substrates for Faecalibacterium prausnitzii.

How do high-protein diets affect gut health?

Promote harmful metabolites (e.g., ammonia, H₂S), reducing gut health.

How does the microbiota differ between traditional and industrialized populations?

• Traditional microbiota: Enriched in fiber-degrading taxa (e.g., Prevotella, Roseburia), linked to lower disease prevalence.

• Industrialized microbiota: Reduced diversity, loss of VANISH taxa, associated with chronic diseases like IBD and obesity.

Name two common probiotic species and their benefits.

• Bifidobacterium spp.: SCFA production and immune modulation.

• Lactobacillus spp.: Enhances epithelial repair and reduces inflammation.

What are prebiotics, and give an example?

Non-digestible fibers that stimulate beneficial microbes. Example: Inulin.

What is the role of FMT (Faecal Microbiota Transplantation)?

Restores microbial diversity, effective for recurrent C. difficile infections.