Microbiota & Human Holobiont: Exam Revision Sheet

1. 📌 Essentials

• The holobiont: host + associated microbes; considered a supra-organism.
• Microota includes bacteria, viruses fungi, archaea; critical for health.
• Major acquisition period: perinatal life; influenced by delivery mode (vaginal vs. C-section).
• Enterotypes: dominant microbiota profiles—Bacteroides, Prevotella, Ruminococcus.
• Microbiota diversity varies but shares core metabolic functions across individuals.
• Critical barriers: mucus layer, antimicrobial peptides, immune tolerance.
• Symbiosis types: mutualism, commensalism, pathogenic (pathobionts).
• Main functions: digestion, vitamin synthesis, immune modulation, energy production.
• Dysbiosis: loss of beneficial microbes, pathogen overgrowth, linked to diseases.
• Microbiota influences neurobehavior via gut-brain axis, producing serotonin (~95%).
• Interventions: probiotics, fecal transplants, targeting microbiome for therapy.
• C-section heightens risks for allergies, autoimmune, neurodevelopmental issues.

2. 🧩 Key Structures & Components