Gut Microbiota - Microbiology Flashcards
What is a microbiome?
A complex community of trillions of bacteria, viruses and fungi that are present in the human body
Where are microbiomes usually found?
Gi tract, oral cavity, lower urogenital tract, upper respiratory system
Which kind of organs do not have microbiomes?
The sterile ones: brain, heart, lower respiratory tract etc.
Why do different parts of the body have different microbiomes?
Because of the differences in the environment, certain bacteria thrive in different environments compared to the rest
What are microbiota?
The types of organisms that are present in an environmental habitat, bacteria, viruses ir eukaryotes.
What are microbiomes mainly composed of?
Bacteria, viruses and fungi are much less
Why is the gut microbiome important to our health?
It performs numerous important biochemical and biological functions for the host.
What is the gut microbiome?
Vast collection of symbiotic microorganisms and metabolites
What is dysbiosis and what does it cause?
Alteration in microbiome and it is associated with disease
What makes gut microbiota important for our health?
Their richness and diversity in microorganisms
What are microbiota?
Beneficial microorganisms that live within us in symbiotic relation –> non-pathogenic
What are pathogens?
Harmful microorganisms that cause disease in human, less than 1% of bacteria are pathogenic
What are opportunistic pathogens?
Cause disease only when the individual is immunocompromised
Where are most gut microbiota present?
In the large intestine and mainly in the cecum, less bacteria are found in the small intestine
Why are there only few bacteria in the stomach?
Because of the acidity of then stomach only few can survive and thrive
How many bacteria does the colon contain compared to the small intestine?
More than 1000 fold more bacteria
Gut Microbiota Distribution:
Colon: > 10^11/ml
Stomach: 10^2 or 10^4 / ml
Small intestine: 10^7 to 10^8/ml
How many bacteria does the human body have compared to human cells?
10 times more bacteria than human cells
How many different species of bacteria have been identified?
10000 different bacterial species
How many genes does the gut microbiome have?
3.3 million genes
Are human microbiomes identical to one another? Why?
No, they are not identical, even if people are twins and live in the same home.
That is because of their different lifestyles, environments and habits.
What is the human microbiome like in healthy conditions?
Diverse, rich and complex
Thick mucus layer
Protects against penetrating pathogens
What are the roles of the gut microbiome?
- Protection against pathogens
- Synthesis of vitamins
- Immune system development
- Promotion of intestinal angiogenesis
- Promotion of fat storage
- Short Chain Fatty Acids Production
- Modulation of CNS
How does the gut microbiome help with immune system development?
Lamina propria knows which the microbiota are and can thus differentiate between them and pathogens
How are short chain fatty acids formed?
Through fermentation of dietary fibre
How is the production of SCFA important?
Promote the gut layers of epithelium and help with immunity.
What are the functions of gut microbiota?
Digestion
Defense
Detoxification
Gut Microbiota Function: Digestion
Synthesise secondary bile acids
Metabolizes indigestible carbohydrates
Gut Microbiota Function: Defence
Maintains gut homeostasis
Stimulates host production of antimicrobial peptides and secretory IgA
Maintains gut mucosal barrier
Gut Microbiota Function: Detoxification
Antibiotics alter the microbiome, certain inactivate orally ingested digoxin
Metabolises environmental chemicals
Which factors influence microbiome development?
Birth and Perinatal Colonisation (C-section or normal birth)
Familial Exposure (Household factors)
Antibiotics & Other Drugs (Impact Diversity & Quality)
Host Susceptibility (Genetic Factors)
Diet & Food Quality (High Fibre & Complex Carbs)
How does C-section affect microbiome?
The newborn does not pass through the vaginal tract so it does not collect the healthy microbiota from the mother.
Higher chance of becoming obese
Where do microbiomes come from?
They are obtained from mother during birth and breast feeding
When is the infant microbiome established?
During the first year of life