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Unit 11: The Human Microbiota - Coggle Diagram
Unit 11: The Human Microbiota
The microbiota
Human Microbiome Project
Identify all the major organisms comprising the human microbiota in 'normal' people
Determine if there are associations between change in the microbiota and the development or progression of disease
Develop tools to better conduct studies
The gut microbiota --> best studied human microbiota
Definition
Microorgansims that reside on and within the human body
Functional roles of the microbiota
Gut microbiota
Most microbes in the large intestine
Bacterial phyla in the gut
Colon
Bacteroidetes
Firmicutes
Small intestine
Firmicutes
Proteobacteria
Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, Verrucomicrobia
pH increases, oxygen level decreases along the gut
Availability of nutrients
Functions
Metabolic functions
Vitamin synthesis
Metablize non-digestible carbohydrates
Metabolite transformation and absorption
Structural functions
Intestinal barrier fortification
Tightening of junctions
Immune system development
Protective functions
Pathogen displacement
Production of antimicrobial factors
Metabolites
Short chain fatty acids (SCFA)
Butyrate - key energy source, affects glucose and energy homeostasis, potential anti-cancer activity
Propionate - energy source, transferred to the liver (promotes energy homeostasis), satiety signaling
Acetate - most abundant, co-factor for growth of other bacteria, central appetite regulation
Composition
Commensals - don't benefit or harm the host
Symbionts - health-promoting functions
Pathobionts - have the potential to induce pathology
Colonization resistance
Direct
Bacteriocins
Nutrient depletion
Type VI secretion systems
Indirect
Antimicrobial peptide production
Bile and metabolism
Epithelial barrier maintenance
Changes in the microbiota
Dysbiota
changes in the microbiota are associated with gastrointestinal diseases
less symbionts and diversity and richness
increased pathobionts, immunigenicity
Obesity and gut microbiota
Microbiota transplant to mice --> increased adiposity in the obese twin microbiota transplant mouse
Factors that alter the microbiota
Diet (plant-based vs protein rich)
Diet>genetics
Cigarettes --> increased bacteriodetes and proteobacteria
Antibiotics --> depletion of healthy microbes, decreased bacterial diversity
IBD
Fecal microbiota transplants (FMT)
Reintroducing healthy bacteria to people who have c-diff
Cryoprotector added to poo --> pushed through filter --> frozen and sent out
Inserted through colonoscopy, pill, or nose tube